Spectrum 101: An Introduction to Spectrum Management

MTR 04W0000048

MITRE TECHNICAL REPORT

Spectrum 101

An Introduction to Spectrum Management

March 2004

John A. Stine

David L. Portigal

Sponsor: OASD NII Spectrum Policy

Directorate

Contract No.: DAAB07-03-C-N206

Dept. No.: W805 Project No.: 0704C550-CA

Approved for Public Release;

Distribution Unlimited.

Washington C3 Center

McLean, Virginia

Approved for Public Release; Distribution Unlimited

Case # 04-0423

Foreword

Each day the military relies on spectrum-dependent technologies to complete its

missions. New technologies found in radars, sensors, satellites, radios, and wireless devices

make information superiority a reality and are an integral part of military operations. The

effectiveness of ships at sea, soldiers in the field, and planes in the sky depend on the

capabilities of these systems. In turn, the capabilities of these systems are dependent on the

unseen resource of spectrum.

In the past, the availability of this unseen resource was a minor issue for the DoD, as

there was ample spectrum access to meet its needs. However, today, new technologies, the

needs of other users (government and commercial), and the proliferation of wireless

technologies worldwide have made maintaining even current spectrum allocations difficult.

New, exciting wireless communication products are creating a large demand for spectrum.

Wireless subscriber services are growing rapidly worldwide. Emerging countries, in an

effort to modernize, are choosing to deploy wireless infrastructure in lieu of wired

infrastructure since it costs less. All of these factors make a more competitive environment

for worldwide spectrum access.

As the recent operations in Afghanistan and Iraq can attest, the DoD achieves much of its

military capability from exploiting technology, especially information technology. Military

capability is dependent on spectrum availability and the current military transformation will

make it more dependent in the future. Unless the DoD manages spectrum smartly it will

forfeit its potential capability. This document provides a broad background of the issues in

spectrum management so that personnel who work in DoD spectrum management

organizations, members of government and DoD who make decisions affecting the allocation

and allotment of spectrum, and DoD program managers who oversee the development of

spectrum-dependent systems can better grasp the complexity of spectrum management and

their role in protecting military access to spectrum and developing and acquiring systems that

use it efficiently. This document provides a repository of basic concepts that are relevant to

these tasks so that players in spectrum management activities can perform these functions

most effectively.

Transformation of the military to enable the vision of “Network Centric Warfare”

promises more effective and efficient use of military force. This transformation will not be

possible without adequate spectrum access to support it.

iii

Preface

This paper has been written to provide an introduction to Spectrum Management with a

DoD perspective. It assumes an audience that is unfamiliar with radio communications

theory, with the current allocation and use of spectrum, and with the processes involved in

managing spectrum. Therefore, it begins by providing an introduction to basic concepts in

radio communications theory in order to build the novice’s intuition so that he might

subsequently understand the rationale for the current allocations and the methods for

managing spectrum. It attempts to give a historical record of how these processes and

allocations came to be. It describes the current spectrum management process to include the

major players and the procedures they use to make decisions. Finally, it gives a brief

introduction to some new technologies that are being introduced and their ramifications on

the spectrum management process. Thus, this paper has been written as both a tutorial and a

basic reference for new players in the spectrum management business.

Use of this document does not require a sequential reading. Each section is reasonably

self-contained. The key concepts of each section are summarized in its introduction and

conclusion. If the reader feels reasonably confident that he understands the concepts as laid

out in these two subsections, then he has sufficient knowledge to undertake the rest of the

report. The body of each section provides greater depth into the material. If the material

becomes so challenging that the reader is not likely to gain from reading it, we recommend

that the reader just skip to the next subsection and continue from there. The concepts in this

paper are presented in a descriptive way and thus do not rely on the reader’s grasp of the

preceding concepts.

Table of Contents

Section Page

1. The Basics: What is Spectrum? 1-1

1.1 Signals 1-1

1.2 Modulation 1-3

1.2.1 Sinewave Modulation 1-4

1.2.2 Pulse Modulation 1-7

1.3 Frequency Content and Bandwidth 1-9

1.3.1 Frequency Content of Modulated Sine Waves 1-9

1.3.2 Frequency Content of Pulses 1-10

1.3.3 Signal Multiplexing 1-11

1.3.4 Spectrum Capacity 1-11

1.4 Transmission, Propagation, and Reception 1-12

1.4.1 Spreading and Attenuation 1-13

1.4.2 Absorption 1-14

1.4.3 Reflection 1-14

1.4.4 Diffraction 1-14

1.4.5 Refraction 1-15

1.4.6 Interference 1-16

1.4.7 Harmonic and Intermodulation Distortion 1-18

1.5 Transmission Power 1-21

1.5.1 Noise 1-22

1.5.2 Signal to Noise Ratio 1-22

1.5.3 The Decibel 1-23

1.5.4 Other Decibel Units 1-24

1.6 Time of Transmission 1-25

1.7 Frequency 1-27

1.7.1 Effect on Electronics 1-28

1.7.2 Effect on Antennas 1-28

1.7.3 Effect on Propagation 1-29

1.8 Summary 1-31

2. The History of Regulation 2-1

2.1 The Birth of Regulation 2-1

2.2 The Birth of Spectrum Management 2-2

2.3 The Communications Act of 1934 2-4

2.4 Maturing of International Regulation 2-5

vii

2.5 The Formation of the National Telecommunications and Information

Administration (NTIA) 2-6

2.6 Summary 2-6

3. The Basics: Spectrum Allocation 3-1

3.1 The Traditional Administrative Approach to Spectrum Management 3-1

3.2 Definitions (As Defined by the ITU Radio Regulations) 3-2

3.3 United States Frequency Allocations 3-2

3.4 Determining Allocations 3-8

4. Department of Defense Use of Spectrum and Threats to that Use 4-1

4.1 DoD Capabilities Derived from Use of Spectrum 4-1

4.2 Some Salient Factors 4-2

4.3 System Tradeoffs 4-4

4.4 Spectrum Losses and Restrictions 4-5

4.4.1 Low Power Unlicensed Devices 4-5

4.4.2 General Considerations 4-6

4.4.3 Some Specific Cases of Spectrum Loss 4-7

4.4.4 Ultra Wideband 4-9

4.4.5 Public Sector Challenges 4-10

4.4.6 Government Coexistence Challenges 4-10

4.5 Maintenance of Spectrum Capability 4-11

4.6 DoD Use of Spectrum in the United States and its Possessions (US&P) 4-11

4.6.1 Test and Training 4-11

4.6.2 Posts, Camps, Stations, and Ports 4-13

4.6.3 Military Operations 4-14

4.6.4 Coordination with Neighboring Countries 4-14

4.7 DoD Use of Spectrum Outside the US&P 4-15

4.7.1 Host Nation Support 4-15

4.7.2 International Spectrum Supportability 4-15

4.8 Summary 4-16

5. Spectrum Management Organizations and U.S. Participation in World

Radiocommunication Conferences 5-1

5.1 International Spectrum Management 5-1

5.2 National Spectrum Management 5-4

5.2.1 The National Telecommunications and Information Administration (NTIA) 5-4

5.2.2 The Federal Communications Commision (FCC) 5-7

5.3 International Negotiation 5-9

5.3.1 The Department of State Organization that Handles International

Communications Issues 5-9

5.3.2 Procedures for WRC Participation 5-10

viii

5.4 Impact of the Dual Management Scheme 5-12

5.5 Summary 5-13

6. Spectrum Management within the Department of Defense 6-1

6.1 DoD Spectrum Management Organizations 6-1

6.2 DoD Spectrum Management Planning Processes 6-3

6.2.1 Strategic Planning 6-4

6.2.2 Planning for Spectrum Supportabilty 6-7

6.2.3 Operational Planning 6-14

6.3 DoD Spectrum Operations (Assignments) 6-15

6.3.1 Continental United States (CONUS) 6-15

6.3.2 OCONUS Permanent/Fixed 6-16

6.3.3 Battlespace Spectrum Management (BSM) 6-16

6.4 DoD Spectrum Management Systems and Tools 6-18

6.4.1 Spectrum Management and Supportability Tools 6-18

6.4.2 Overarching Spectrum Architecture 6-20

6.5 Summary 6-20

7. Technological Advances and their Impact on Spectrum Management 7-1

7.1 Information Efficient Technologies 7-1

7.1.1 Source Coding 7-2

7.1.2 Redundancy Reduction 7-2

7.1.3 Data Compression 7-2

7.1.4 Error Correction 7-3

7.2 Spectrum Efficient Technologies 7-4

7.2.1 Advanced Modulation 7-4

7.2.2 Pulse Shaping 7-4

7.2.3 Receiver Capability 7-5

7.2.4 Tradeoffs 7-6

7.3 Digital Signal Processing Technology 7-6

7.3.1 Identifying Frequency Content 7-7

7.3.2 Software-Defined Radio 7-8

7.4 Spatial Reuse Technologies 7-8

7.4.1 Directional Antennas 7-8

7.4.2 Networking 7-9

7.4.3 Spread Spectrum Communications 7-11

7.4.4 Signal Polarization 7-14

7.4.5 Smart Antennas 7-14

7.5 Dynamic Spectrum Management 7-17

7.5.1 Spectrum Mining 7-17

7.5.2 Dynamic Channel Assignment 7-18

7.6 Alternative Perspectives on Efficient Spectrum Management 7-20

7.7 Summary 7-21

8. Real World Constraints in Spectrum Management 8-1

8.1 Legacy Allocations 8-1

8.2 Legacy Equipment 8-2

8.3 Desirable Features of Spectrum Assignments 8-2

8.4 Transition Issues 8-3

8.5 Changing Spectrum Use 8-3

8.6 Conclusion 8-4

List of References RE-1

Appendix A. DoD Spectrum Use A-1

Appendix B. Department of Defense Electromagnetic Spectrum Management Plan B-1

Glossary GL-1

Acronyms B-1

Terms B-8

List of Figures

Figure Page

1-1. Representations of a 40kHz sine wave 1-2

1-2. Representation of a 400 Hz square wave 1-4

1-3. Example of a sine wave information signal modulating a higher frequency sine

wave carrier 1-5

1-4. Example modulation of a digital signal 1-6

1-5. Pulse types 1-7

1-6. Pulse modulation methods 1-8

1-7. Frequency content of AM modulated signals 1-9

1-8. Frequency content of a rectangular pulse as a function of its dimensions 1-10

1-9. Frequency content of a rectangular pulse for baseband and sine wave pulses 1-11

1-10. Example of using different carrier frequencies to multiplex multiple signals on

the same media 1-11

1-11. The transmission and reception of EM radiation 1-13

1-12. Reflection of an electromagnetic wave 1-14

1-13. Diffraction of a wave around a building 1-15

1-14. Wave refraction (propagation is slower in Medium 2 than in Medium 1) 1-16

1-15. Multipath interference 1-17

1-16. Cross band interference 1-18

1-17. Outputs of the non-linear mixing of two input signals at frequencies f

and f

1-19

1-18. Antenna end of a typical receiver or transmitter 1-20

1-19. Intermodulation distortion at a receiver 1-21

1-20. Effect of noise on a detected signal in the time domain 1-22

1-21. Signal and noise in the frequency domain 1-23

1-22. EM signal absorption by atmospheric gases 1-30

3-1. Spectrum allocation 3-3

3-2. Allocation of spectrum to federal government and non-federal government use

as a percentage of bandwidth 3-6

3-3. Percentage of total number of assignments and licenses found in each band

3-7

3-4. Percentage of total number of assignments to each federal government function

by band

3-8

3-5. Example frequency allocation entries in the ITU-R Radio Regulations and the

NTIA Red Book 3-9

5-1. Organization of the ITU 5-2

5-2. Spectrum use regions 5-3

5-3. Organization of the NTIA 5-4

5-4. Organization of the NTIA Office of Spectrum Management 5-5

xii

5-5. FCC organization chart 5-8

6-1. Organizations that cooperatively manage DoD spectrum 6-3

6-2. Organization to study allocation issues for WRCs 6-7

6-3. Proposed alignment of spectrum supportability activities and spectrum

certification stages with the defense acquisition management framework 6-10

6-4. The spectrum certification process 6-12

7-1. Comparison of the spectral content of pulses that change gradually vs. rapidly.

The pulse in the time domain is shown on the left and their use of spectrum is

shown on the right. 7-5

7-2. Comparison of omni-directional and directional antenna coverage. 7-9

7-3. Effect of pulse width on spectral content. The shorter pulse width τ

spreads the

spectrum further than the τ pulse width. 7-12

7-4. Example of Direct Sequence Spread Spectrum (DSSS) 7-13

7-5. Anti-jam characteristics of DSSS 7-13

7-6. An example of constructive and destructive interference from two signals that

are transmitted in phase from two adjacent antennas based on direction of

propagation. 7-15

7-7. Differences in received signals caused by multipath arrival of signals at the

receiving antennas 7-16

7-8. Graph of the Erlang C formula showing the benefit of statistically multiplexing

channels to support randomly arriving traffic 7-18

7-9. A notional layout of members of a military formation showing subscription to

multicast groups 7-20

xiii

List of Tables

Table Page

1-1. The International Telecommunications Union – Radiocommunication sector band

designations 1-26

1-2. Letter designations for radar frequency bands (IEEE Std 521 – 2002) 1-27

3-1. Frequency bands where government has exclusive primary status 3-5

3-2. Frequency bands where the government is the exclusive user 3-5

5-1. AAG frequency assignment bands 5-6

6-1. DD Form 1494 submission lead time guidelines from AFI 33-120 6-13

6-2. FAA frequencies and bands 6-16

xiv

Section 1

The Basics: What is Spectrum?

The pervasive presence of commercial radio, wireless telephony, television, Global

Positioning Systems (GPSs), Doppler weather RADAR, and other wireless technologies

provides the average individual with the intuition of the goal of spectrum management.

Multiple radiated signals can be engineered to coexist in the same physical space and then be

selectively detected by using the appropriate equipment and channel. The objective of

spectrum management is to enable the optimum number and types of services to coexist.

Radio signals are able to coexist in the same physical space on account of the ability to

isolate signals by using the physical characteristics of their transmissions. One of these

characteristics is spectrum. Radio frequency spectrum is the continuum of frequencies of

electromagnetic radiation from 9,000 Hz (9 kilohertz) to 300,000,000,000 Hz (300

gigahertz). In the simplest sense, one may isolate multiple users of spectrum by allocating

different bands of this continuum to them.

Spectrum management, however, is much more complicated than simply allocating

frequencies. It is desirable and necessary to reuse spectrum. Thus, other physical

characteristics of transmissions are also used to isolate spectrum users. Spectrum

management is the oversight of all characteristics of electromagnetic radiation. The goal is

to prevent users from harmful interference while allowing the optimum use of the spectrum.

The problem is complex since the characteristics of electromagnetic radiation vary with time,

space, and frequency.

This section provides a simplified description of the process by which information is

modulated onto a signal and then transmitted and received. It explains basic concepts of

signals, frequency, modulation, bandwidth, propagation, and reception to provide the reader

with a technical foundation to understand the approaches that are used to manage spectrum.

1.1 Signals

A signal is broadly defined as a detectable quantity (e.g., current, voltage,

electromagnetic field) that varies in time. An important signal for radio communications is

one where the quantity varies as a periodic sine wave as depicted in Figure 1-1a. This signal

is presented in the time domain, that is, the quantity is shown to change with time. The

horizontal axis is time and the vertical axis is the value of the changing quantity, such as

voltage. As illustrated on the drawing, the portion of the signal that repeats itself is called a

cycle, and the time between repetitions is its period.

0.02 0.04 0.06 0.08 0.10

t (msec)

-A

f (kHz)

612

24 300

d (kilometers)

20 40

80 1000

1 cycle

Period (T)

Wavelength (λ)

a. Time domain representation

b. Frequency domain representation

c. Wave propagation representation

Velocity, V = 3 · 10

m/sec

Propagation direction

-A

AmplitudeAmplitudeAmplitude

Figure 1-1. Representations of a 40kHz sine wave

Frequency is the number of cycles that occur in one second and is defined in units of Hertz,

which is another name for cycle per second. The frequency of a signal is the reciprocal of its

period. The amplitude of the signal is half the peak-to-peak separation of the quantity that is

changing with time, e.g., voltage.

A second way of presenting signals is in the frequency domain. Figure 1-1b presents this

same sine wave in the frequency domain. A pure sine wave appears as a single line in the

frequency domain. Note that the horizontal axis has units of Hz and that the vertical axis has

the units of the changing quantity. The position of the line on the horizontal axis

corresponds to the signal’s frequency and the height of the line corresponds to the signal’s

amplitude. This is the domain that frequency spectrum is understood and managed.

A wave is a signal that exists in space and varies with time and location. We say that

waves propagate through space. If the signal is a wave, then there is still a third way to

present this signal and it looks very similar to the first, see Figure 1-1c. It is a depiction of

the signal’s propagation. Distance units rather than time calibrate the horizontal axis. The

significance of this depiction is that it provides the understanding for wavelength. It is the

distance that separates the start of each cycle. A signal’s wavelength is the product of a

signal’s period and the velocity of its propagation. An observer that remains stationary in a

space through which a wave propagates will observe the varying quantity in the time domain.

Table 1-1 lists frequencies and their corresponding wavelengths.

Any variation to a sine wave will add additional frequency content. A classic method to

illustrate this fact is to observe the frequency content of a square wave. We provide this

example to show that practical signals contain multiple frequencies simultaneously and that a

reasonable replication of the signal can be made with a subset of those frequencies. In

Figure 1-2a we illustrate a 400 Hz square wave. As illustrated in Figure 1-2b, this square

wave has infinite frequency content with the magnitude of each frequency component

decreasing with frequency. (Each of the lines corresponds to a pure sine wave.) It is

undesirable to transmit signals with large frequency content, and they will frequently be

filtered so that only a restricted subset of the frequency content is transmitted. In

Figure 1-2c, we show a reconstructed square wave signal that only includes the frequency

content beneath 5000 Hz. For practical purposes the square wave can be recognized.

Another example demonstrating that frequency content can be lost is seen in sound

reproduction. The human ear, generally, can detect signals between 20 Hz and 20 kHz.

However, a smaller range of the frequency content of sound will not render it unintelligible.

For example, a telephone reproduces sound with frequencies as high as 3 kHz, a commercial

AM radio station reproduces sound up to 5 kHz, and a commercial FM station reproduces

sound with frequencies up to 15 kHz. All are intelligible although there is a definite

difference in fidelity.

1.2 Modulation

Modulation is the process of transferring information onto electromagnetic radiation for

the purpose of information transmission. There are two general types: In the first,

information is transferred onto a continuous sine wave, in the second, pulses are used.

050001

1.5

0 0.002 0.004 0.006 0.008 0.01

a. Time domain representation

b. Frequency domain representation

c. Square wave reproduction using frequency

components beneath 5 kHz

Amplitude

Figure 1-2. Representation of a 400 Hz square wave

1.2.1 Sinewave Modulation

Sine wave modulation is accomplished by changing one of the descriptive parameters of

the sine wave: amplitude, frequency, phase, or time of transmission. In Figure 1-3, we show

an information signal impressed onto a sine wave (a.k.a. sine wave carrier) as an amplitude-

modulated signal and as a frequency-modulated signal. We do not show a phase-modulated

signal for this continuous information signal since it would not be distinguishable from the

FM signal when displayed in this one-dimensional plot. However, if the information signal

0 0.002 0.004 0.006 0.008 0.01

a. Information signal

b. Amplitude modulated signal

c. Frequency modulated signal

Amplitude

AmplitudeAmplitude

Figure 1-3. Example of a sine wave information signal modulating a higher frequency

sine wave carrier

is discrete as in a digital signal, there is a very definite difference in how the modulated

signal looks. In Figure 1-4, we show a digital signal that modulates a carrier using the

frequency and phase

0 0.002 0.004 0.006 0.008 0.01

0.5

0 0.002 0.004 0.006 0.008 0.01

a. Digital information signal

b. Frequency modulated digital signal

aka Frequency shift keying

c. Phase modulated digital signal

aka Phase shift keying

Amplitude

AmplitudeAmplitude

Figure 1-4. Example modulation of a digital signal

characteristics. In this figure we show that a bit of information is associated with each signal

state, as defined by its frequency in Figure 1-4b and by its phase in Figure 1-4c. Modulation

of digital signals can be more complex where the signal can assume multiple different states,

and each state is defined by the combination of its frequency, amplitude, and phase. Each

state of such a signal can represent multiple bits of information rather than just the one bit as

shown. For example, each state of a signal with eight states can represent three bits. The

word “symbol” is frequently used to refer to both the signal state and the combination of bits

that each state represents. Much effort is invested in designing these multiple state signals

since they provide the opportunity to increase the information-carrying capacity of the signal.

Note that there are engineering tradeoffs since these designs require more sophisticated

radios and are more susceptible to the effects of adverse environmental conditions.

1.2.2 Pulse Modulation

A pulse consists of a short burst of radiation. These pulses may be a simple increase in

the electromagnetic field (referred to as baseband, meaning there is no sinusoidal waveform

during the pulse) or a short burst of a sinusoidal wave. Figure 1-5 illustrates the difference

between the two types of pulses. The type of burst and the frequency of the sinusoidal wave

will determine what part of the spectrum the signal uses. Details follow in the next section.

Information is modulated onto the pulses by changing their characteristics. The most

common characteristics used follow:

Pulse amplitude: The amplitude of a pulse within a prescribed time slot is proportional to a

characteristic of the information (e.g., amplitude is proportional to the amplitude of an analog

signal, a.k.a. pulse amplitude modulation [PAM]).

Pulse duration: The width of the pulse is proportional to a characteristic of the information

(e.g. duration is proportional to the amplitude of an analog signal, a.k.a. Pulse width

modulation [PWM]).

a. Baseband pulse

b. Sine wave pulse

Amplitude

Figure 1-5. Pulse types

Pulse position: The position of a pulse within a prescribed time slot is proportional to a

characteristic of the information (e.g., position is proportional to the amplitude of an analog

signal, a.k.a. Pulse Position Modulation [PPM]).

Pulse occurrence: The presence of a pulse in a particular time slot provides the information

(e.g., time slots may correspond to bits and the presence of a pulse may correspond to a

particular value of that bit). Another use for the presence of a pulse is to indicate the relative

change in an analog signal, a.k.a. Pulse Code Modulation (PCM).

Figure 1-6 illustrates the different types of pulse modulation. Pulse type emissions were

used in the earliest communications systems. The first radio invented by Marconi used

baseband pulses. The initial advances in communications were to use sinusoidal pulses.

Pulses are also especially useful in radar applications. Radar systems send pulses and then

wait for an echo from a target. Ultra wideband communications and radars are based on the

use of pulses.

a. Pulse amplitude

b. Pulse duration

c. Pulse position

d. Pulse occurrence

AmplitudeAmplitude

Amplitude

Figure 1-6. Pulse modulation methods

1.3 Frequency Content and Bandwidth

1.3.1 Frequency Content of Modulated Sine Waves

The frequency content of the modulated signal consists of the carrier component and the

upper and lower bands of frequencies associated with the frequency content of the

information. In Figure 1-7, we illustrate the frequency content of the AM modulated signal.

Its content consists of the carrier component and the carrier plus and minus the information

frequency content. An AM signal requires spectrum bandwidth equal to twice that of the

information signal. FM modulated signals and digital signals will also have bands of

frequency content on both sides of a carrier, but the size of these sidebands is generally

larger. Their size depends on how much the frequency is allowed to change in the FM signal

and how rapidly signals are shifted in digital communications. As an example, a commercial

AM station has a bandwidth of 10 kHz, a commercial FM station has a bandwidth of 200

kHz, and a commercial television station has a bandwidth of 6 MHz. A highly efficient form

of AM modulation is single sideband modulation where one of the sidebands of an AM

signal is isolated from the carrier and the other sideband prior to transmission. Its bandwidth

is that of the frequency content of the information signal.

0 2000 4000 6000 8000

-W

a. Frequency content of the AM signal

illustrated in Figure 1-3b

b. Frequency content of a typical AM signal

where W is the bandwidth of the information

AmplitudeAmplitude

Figure 1-7. Frequency content of AM modulated signals

1.3.2 Frequency Content of Pulses

The spectral content of a pulse is a function of its duration, shape, and amplitude. A well

understood pulse is the rectangular pulse. Figure 1-8 illustrates the relation of the breadth of

its frequency content to the dimensions of the pulse. We see that the shorter the pulse, the

wider and lower the spectral content. Figure 1-9 illustrates the difference in frequency

content of a baseband pulse and a sine wave pulse.

-1

a. A pulse in the time domain

b. Spectral content of a pulse

Amplitude

Figure 1-8. Frequency content of a rectangular pulse as a function of its dimensions

a. Baseband pulse: Spectral content starts

at 0 Hz

b. Sine wave pulse: Spectral content centered

at the frequency of the sine wave

Frequency of the

sine wave

Amplitude

Figure 1-9. Frequency content of a rectangular pulse for baseband and sine wave

pulses

1.3.3 Signal Multiplexing

Multiple modulated signals can coexist in the same medium by separating their carrier

frequencies so that their sidebands do not overlap. See Figure 1-10. In Section 7 we

describe modulation techniques that allow multiple signals to occupy the same spectrum

simultaneously.

Figure 1-10. Example of using different carrier frequencies to multiplex multiple

signals on the same media

1.3.4 Spectrum Capacity

As described, bandwidth is a measure of the breadth of spectrum that is used to provide a

service. The amount of information that can be sent in a signal is proportional to its

bandwidth. A well known formula that expresses the limit of capacity for digital signals is

provided by the Shannon–Hartley Theorem:

(

)

log 1CBW SNR=+

where C = channel capacity (b/s)

BW = bandwidth (Hz)

SNR = signal-to-noise power ratio

This formula shows that capacity is also dependent on Signal-to-Noise (SNR). (See Section

1.5.2.) High bandwidth and high power signals will have more capacity than lower

bandwidth and lower power signals. These factors become tradeoffs in the design of

communications systems. For reasons we will explain in Section 1.7.1, higher bandwidth

signals are usually sent at higher frequencies.

1.4 Transmission, Propagation, and Reception

A radio transmits a signal by driving a current on an antenna where the current amplitude

is the changing quantity of the signal. This changing current, in turn, induces an

electromagnetic field about itself, with a field strength that corresponds to the current

amplitude. This electromagnetic field propagates away from the antenna as a wave at the

speed of light. As the signal propagates, it attenuates. At a distant receiver, the

electromagnetic wave passes across the receiver’s antenna and induces a current.

Figure 1-11 illustrates this process. Note that all electromagnetic radiation in the area will

pass across the receiving antenna. In order for the receiver to detect the correct signal, it

must be able to isolate the desired signal from all others. If the receiver is in range of two

transmitters using the same frequency band that it is trying to receive, then the receiver may

not be able to properly capture the desired signal for demodulation and what it does capture

may be unintelligible. The spectrum management process attempts to prevent this situation

from occurring. The goal is not to prevent transmitters from using the same frequencies but

to ensure that receivers are capable of receiving and distinguishing the desired signals. So

there may be more than one transmitter using the same carrier frequency as long as the

receivers are able to distinguish the desired signal over the others.

Transmitter

Current to

the antenna

Induced field

from antenna

current

EM Wave

Propagation

Receiver

Current from

the antenna

Induced current

from changing

EM field

Figure 1-11. The transmission and reception of EM radiation

Terrain, atmosphere, and other factors can affect propagation. Sections 1.4.1 through

1.4.5 describe the basic propagation phenomena that affect signal strength. These

phenomena illustrate exactly how complex signal propagation can be, especially in terrestrial

environments. Reception at an antenna depends on a signal’s strength and the presence of

other signals at the receiver. Sections 1.4.6 and 1.4.7 discuss interference and some of the

unintentional sources of interference that may come from authorized users of spectrum.

1.4.1 Spreading and Attenuation

Spreading and attenuation are the reductions of signal strength that occur as a result of

the distance propagated. Spreading is the loss that occurs due to the geometric dispersion of

the signal. For example, consider a signal that propagates spherically. If we consider the

signal power for each concentric sphere to be the same, the strength per unit area decreases

as the sphere gets larger. Attenuation is the reduction of signal strength that results from

propagating through media.

1.4.2 Absorption

All material media through which signals propagate (e.g. air, glass, water, etc.) consists

of atoms and molecules. As an electromagnetic wave passes through such a medium, energy

is transferred from the wave to the atoms and molecules of the medium. Once absorbed by

the medium, the energy is lost forever.

1.4.3 Reflection

Reflection occurs when a wave strikes the boundary of two media and some or all of the

wave’s energy does not enter the new medium. The wave returns to and continues to

propagate in the first medium although usually in a different direction. Figure 1-12

illustrates electromagnetic wave reflection.

1.4.4 Diffraction

Diffraction is the phenomenon that allows electromagnetic waves traveling in a straight

path to reach behind obstacles. The principle that governs this behavior is referred to as

Huygens’ principle. Huygens’ principle states that every point on a spherical wavefront can

be considered a source of a secondary wavefront. This principle explains how a signal can

be received behind a large obstacle such as a mountain or a large building. Figure 1-13

illustrates diffraction around a building. The portion of the area behind these obstacles that

the secondary wave does not reach is called the shadow zone. The effect of moving in and

out of shadow zones on account of mobility is referred to as slow fading.

Incident wave

Reflected wave

Angle of

incidence

Angle of

reflection

Reflecting surface

Figure 1-12. Reflection of an electromagnetic wave

Shadow zone

Shadow

zone

b. Side view

a. Top view

Figure 1-13. Diffraction of a wave around a building

1.4.5 Refraction

Refraction can be thought of as the bending of the direction of propagation of an

electromagnetic wave. Refraction occurs because of changes in wave velocity that are

caused by differences in the properties of media through which it propagates.. Figure 1-14

illustrates a refracted wave. In this example, the velocity is higher in medium one than

medium two. The portion of the wave front that enters the new medium first will change

velocities before the rest of the wave. Thus, it will travel a different distance than the portion

of the wave in the old medium resulting in the redirection of the wave front. In any specific

medium, the velocity of an electromagnetic wave is inversely proportional to its density.

Since the earth’s atmosphere has different densities at different elevations, signals that are

sent toward the sky at an appropriate angle will refract back toward the earth’s surface.

Similarly, signals directed toward earth may be refracted back toward the sky.

Medium 1

Medium 2

Angle of

incidence

Angle of

refraction

Figure 1-14. Wave refraction (propagation is slower in Medium 2 than in Medium 1)

Refraction may also occur in the ionosphere where the different electron densities cause

the refraction. The ionosphere is created by the ultraviolet radiation from the sun interacting

with the atmospheric gases. At higher elevation a greater percentage of the gases are

ionized, but since the density of gases is lower, the highest density of ions is not at the top of

the ionosphere. A wave propagating toward the sky will first start to bend back toward the

earth; however, if the wave passes the point of highest density it will bend back the other

way.

1.4.6 Interference

Interference occurs when multiple electromagnetic waves in the same spectrum are

coincident in space. When two or more waves meet at a receiver’s antenna, the resulting

detected signal is the linear superposition of the incident waves (i.e., The signals are added to

each other). Such colliding can degrade the quality of the signal a receiver detects.

Interference can be generated by other transmitters or by multiple versions of the same signal

that have arrived at a receiver along different paths. For example, reflected signals can

interfere with signals that propagated on a direct line of site. This type of self-interference

will occur more frequently as there are more surfaces off of which a signal can reflect. For

this reason, terrestrial transmitters have less range than identical transmitters at higher

altitudes. Figure 1-15 illustrates an example of the destructive interference that may occur

on account of this phenomenon. This type of interference is referred to as multipath

interference. The effect of moving in and out of such interference zones is referred to as fast

fading.

Direct line of sight

Reflected

signal

Detected

signal

Direct

signal

Figure 1-15. Multipath interference

Interference may occur between signals in adjacent frequency bands. We use Figure

1-16 to illustrate the issues. In Figure 1-16a we show the ideal case where a receiver detects

two adjacent signals each arriving with the same power. This could happen if both

transmitters use the same power. and the path losses to the receiver are the same. (Path loss

is the energy lost in the signal due to propagation and the environment. We discuss this

further later in this section.) The receivers then isolate the specified band of the desired

signal. The power of the desired signal is substantially higher than that of the sidebands of

the adjacent signal and is easily received. In Figure 1-16b we show what happens when the

receiver is closer to the adjacent band transmitter. In this example, the location gives the

adjacent transmitter a 10x advantage. (This example exaggerates the sideband amplitude but

in real systems the differences in received strength on account of different path loss can be

greater than 100,000x.) The power in its sidebands prevents reception of the desired signal.

Regulations place demands on how much radiation may occur in the sidebands but even then

other measures are taken to mitigate this interference. For example, a channel normally

separates television stations in the same market. A proposal for increasing spectrum

efficiency is to collocate transmitters so that the relative strengths of their signals are the

same to all receivers. Thus, adjacent channels may be used in the same market. This may

only be practical for broadcast services.

a. Signals on adjacent bands received with the same power

b. Signals on adjacent bands where the adjacent signal has a 10x power advantage

Received channel

Desired signal

Detected signal

Interfering

signal

Interfering

signal

Amplitude

Detected signal

Desired signal

Figure 1-16. Cross band interference

1.4.7 Harmonic and Intermodulation Distortion

A well-known phenomenon that occurs in communications systems is the multiplication

and mixing of signal frequencies in non-linear components of the system. This

multiplication and mixing leads to interference to and from other systems that is not obvious

from the basic system design. Figure 1-17 illustrates the phenomenon. In this example, the

outputs after mixing the two signals in the non-linear device are additional signals at

frequencies that are harmonics of the input signals (i.e., integer products of the original

signal frequencies,

or ) and intermodulation products of the input signals (i.e., sums

and differences of integer multiples of the original signal frequencies,

). Such

mixing can involve more than two input signals and the outputs can occur across a vast range

of the spectrum. Harmonic distortion is the name given to the interference that comes from

the harmonic outputs. Intermodulation (IM) distortion is the name given to the interference

that comes from the IM outputs. Generally, the amplitudes of harmonic and IM products are

11 2 2

nf nf±

much less than the input signals and decrease as the order

of the product increases.

Receivers can receive over a large dynamic range of signal strengths so IM products from

neighboring transmitters can interfere with the reception of a weaker signal from a distant

transmitter.

IM can occur at receivers, transmitters, or external to the radios. Receiver IM (RIM) and

transmitter IM (TIM) occur because there are non-linear devices within these components.

External IM (EIM) occurs since signals mix in unintentional non-linear devices such as

antennas or cables.

Frequency

Amplitude

Figure 1-17. Outputs of the non-linear mixing of two input signals at frequencies

and f

Figure 1-17 attempts to show the spread of harmonic and intermodulation products. The

relative amplitude of the products will differ depending on the characteristics of the mixer.

In radios, filters may be added to help eliminate these unwanted outputs.

Mixer circuits and non-linear amplifiers are common components in receivers and

transmitters. Figure 1-18 illustrates the antenna end of typical receivers and transmitters. As

illustrated, they deliberately include a non-linear mixer circuit. Additionally, the radio

frequency (RF) amplifier may also be non-linear as non-linear amplifiers are less expensive

Product order is the sum of the coefficients of the input frequencies so in the example of Figure 1-17 where

there are two inputs the product order m is determined by

mn n

+ .)

to make and to operate. The significance of this type of transceiver design is that harmonic

and IM distortion can be created inside transceivers both prior to transmission and after

reception.

Local

Oscillator

Amplifiers

...

Figure 1-18. Antenna end of a typical receiver or transmitter

The purposes of the blocks are as follows. The RF amplifier operates on signals in the

range of frequencies that the radio is designed to receive or transmit. The intermediate

frequency (IF) section operates at a frequency that does not change. The local oscillator

generates a sinusoidal signal. This type of radio design enables the radio to operate over a

range of channels. Mixing an incoming RF signal with a local oscillator frequency in a

receiver allows the higher frequency RF signal to be down-converted to a lower IF where the

bulk of the signal amplification and processing is accomplished. In a transmitter, the

opposite occurs where the mixer circuit up-converts the IF signal to a higher frequency RF

signal. In this design, the channel is selected by selecting the local oscillator frequency, i.e.,

RF = f

– IF or RF = f

+ IF.

The role of the RF section in a transmitter is to isolate the desired signal from the mixer

circuit and to amplify it for transmission. The role of the RF section in a receiver is to isolate

the received signal and to preamplify it prior to mixing. In transceivers, the RF filters that

isolate the signals for transmission and reception are different blocks.

In reception, it is possible that two received RF channels can be mixed and then both

enter the IF section, i.e., RF

where IF = f

– RF

and RF

where IF = f

+ RF

. The

interfering RF signal’s frequency is called the image frequency. The range of local oscillator

frequencies and the IF are selected, and filters are designed at the RF and IF sections with the

intent of preventing IM products from leaving the radio or an image frequency from entering

the IF section.

The prices of receivers and transmitters increase with the quality of the RF components.

In order to keep prices of radios and televisions at an affordable price for consumers,

especially in the early days of their use, frequency assignments were made in a way to

minimize the occurrence of intermodulation distortion in receivers. Now that spectrum is

becoming more scarce, many experts propose that regulation be used to mandate better

quality receivers so more channels can be used in the same market.

EIM is a major contributor to co-site interference. Two transmitters that operate close to

each other can transmit IM products due to the mixing of signals at one of the transmitters’

antennas. A receiver operated close to two or more transmitters may receive an IM signal

from those transmitters possibly mixed in its own antenna. Figure 1-19 is an example. The

exact device that causes IM can be very difficult to predict and to prevent. Frequency

assignment is frequently used to help prevent IM distortion. A well-known case of the use of

assignment to prevent IM distortion is to avoid making television assignments on channel 32.

The third harmonic of channel 32 interferes with the signals used by the Global Positioning

Satellite system.

Victim

Receiver

Channel 94

Interfering

Transmitter

Channel 102

Interfering

Transmitter

Channel 98

Figure 1-19. Intermodulation distortion at a receiver

1.5 Transmission Power

Transmission power determines the strength of the electromagnetic (EM) field that

radiates from an antenna and the range that the signal can propagate and still be received.

Since it is desirable to reuse spectrum, the spectrum management process will also regulate

the strength of signal emissions. Restricting the power of transmission limits the coverage of

the transmission; thus, reducing the interference it causes and enabling more reuse of the

spectrum.

A receiver is able to receive a signal so long as it is stronger than noise and other

interfering signals. The following subsections provide a more in-depth discussion of noise

and the measures to quantify the relative strength of signals.

1.5.1 Noise

Noise is defined as the unwanted electrical energy in a receiver’s band of reception. This

noise can be further reduced into two types: correlated and uncorrelated. Correlated noise

comes about as a result of distortion of the signal by radio components. Uncorrelated noise,

the noise we are interested in, is noise that is present regardless of whether there is a signal

present. This noise can be caused by natural phenomenal from the atmosphere, the cosmos,

the sun, heat, the operation of man made devices such as motors or other transmitters, and

noise introduced by the circuitry of receivers. Noise is present in all portions of the spectrum

and is generally modeled as being random and as having the same amplitude across the

spectrum. Much of this noise is unavoidable. Figure 1-20 illustrates what noise may look

like in the time domain and how it would affect a detected signal.

Detected

signal

Noise

Signal

Figure 1-20. Effect of noise on a detected signal in the time domain

1.5.2 Signal to Noise Ratio

Signal to noise ratio is a simple mathematical relationship of the signal level with respect

to the noise level. It is normally expressed as either a ratio of voltages or powers using units

of decibels. Figure 1-21 illustrates the detected signal with noise in the frequency domain. If

the signal strength is substantially larger than the noise, i.e., has a large SNR, then the

receiver can detect the signal. If the signal power is low with respect to the noise, then it

cannot be received, despite amplification at the receiver. The specific quantity that is

considered a high SNR will vary based on the modulation that is used and the quality of the

receiver. However, in many applications, an SNR of 10 decibels is considered a minimum

for reliable performance.

Signal

Noise

Figure 1-21. Signal and noise in the frequency domain

1.5.3 The Decibel

The decibel unit was created to explain acoustic phenomena. Telephone engineers in the

1920s needed a measure to express sound levels. Typically, changes in air pressure

associated with sound are measured in micro Pascals (µPa). However, the average human

can detect signals as low as 20 µPa and as large as 200,000,000 µPa. This very large range

of values makes µPa an ineffective measure. Additionally, in perception, differences in

sound are perceived as relative changes rather than linear changes. A change in sound from

100 to 1000 µPa is perceived just as the change from 1000 to 10000 µPa. So the engineers

decided to base the new unit on the ratio of sound levels and used the logarithm base 10 as its

fundamental unit. They called this unit a Bel, naming it after Alexander Graham Bell, the

inventor of the telephone. Subsequently, they divided the Bel into the 10 parts now called

decibels since a decibel was about the minimum change in sound pressure that a human can

detect. The abbreviation for decibel, dB, has a capital B since a Bel was derived from

Alexander Graham Bell’s last name.

A decibel has two major characteristics: first, it is a ratio of power and second, it is based

on a base 10 logarithm. To make this clearer, we provide two examples of how decibels are

calculated. Say you have an amplifier that will increase the power of an incoming signal

from P

to P

. Say the signal entering the amplifier has a power of 1 mWatt, and the output

has a power of 100 mWatts. The amplification in decibels would be calculated as follows

()

10 10

10 log 10 log 100 20 dB.

⎛⎞

×=×=

⎜⎟

⎝⎠

Say an electromagnetic field is measured at a point very close to its source antenna and found

to be 10,000 times stronger than it is at some destination. Then the path loss would be

calculated as follows

10 log 40 dB.

10,000

⎛⎞

×=−

⎜⎟

⎝⎠

Using the decibel unit greatly simplifies the math involved in calculating the total

changes in signal power in a system. Contributions of individual components and

phenomena can be added rather than multiplied. The challenge is that when one is not

accustomed to using logarithms it is difficult to get an appreciation of the magnitude of

changes. Two numbers are useful, 10 and 3. A signal’s power increases 10 times for 10 dB

and 2 times for 3 dB and decreases by 1/10 times for –10 dB and ½ for –3 dB. Say there is a

power change of 86 dB. The relative power change can be calculated as follows

80 dB 10 10 10 10 10 10 10 10 10

6 dB 2 2 4

86 dB 4 10 .

=×××××××=

=×=

=×

1.5.4 Other Decibel Units

A decibel is a unit in the same sense that a “percent” is a unit. It only has a physical

meaning when there is a reference value. Frequently, it is necessary to provide units for an

actual quantity, such as the strength of a signal or the effectiveness of an antenna. In these

cases, the dB scale is retained but modified by a reference to a specific value. We describe

some of the more popular measures below.

dBm: Power relative to 1 mW. A 100 mW signal is also a 20 dBm signal.

dBW: Power relative to 1 W. A 100mW signal is also a –10 dBW signal. dBm units can

be converted into dBW units by subtracting 30 dB.

dBi: Gain of an antenna with respect to an isotropic antenna, an antenna that transmits with

the same power in all directions. The dBi measure would be used to express the advantage

that is gained by using an antenna with some directionality. It expresses the ratio of

transmitted power in the preferred direction of that antenna as compared to what would be

transmitted in that same direction if the antenna were isotropic where both antennas are

excited by the same power.

dBd: Gain of an antenna with respect to a half-wave dipole antenna. A half-wave dipole

antenna, also referred to as a Hertz antenna, consists of two equidistant wires that extend

from the feed point out ¼ wavelength for a total of ½ wavelength end-to-end. The reference

power is measured in the preferred direction of the dipole, which is perpendicular to the

elements. The value for dBd is measured in the same manner as dBi. A dipole antenna has a

gain of 2.4 dBi. A dBd measure can be converted to a dBi measure and vice versa by adding

or subtracting 2.4 dB respectively.

dBc: The power of a signal referenced to a carrier signal, i.e., if a second harmonic signal at

10 GHz is 3 dB lower than a fundamental signal at 5 GHz, then the signal at 10 GHz is -3

dBc. These units are used to describe in decibels how far down signals and noise are relative

to a known signal.

dBr: A relative power relation between a measured power strength and a suitable reference

signal's power strength. It indicates difference as opposed to actual power strength. When

used, the reference is usually identified.

dBsm: A unit used in conjunction with radar cross sections. It measures the power of a

reflected radar signal from an object relative to the power that would be reflected from a

reference of a copper sphere with a 1 meter square cross sectional area.

dB SPL: A unit of sound pressure that is used to specify the loudness of a sound. The

acronym SPL stands for sound pressure level and the reference (0dB SPL) is 0.0002

dyne/cm

, the threshold of what humans can hear. 70 dB SPL is the level of an average

conversation

1.6 Time of Transmission

Time is relevant to the spectrum management problem in two ways. First of all, multiple

users can use the same spectrum by using it at different times. Second, propagation

characteristics can change in time.

When stations do not use a band of frequencies continuously, those frequencies can then

be shared with other users. Time can be used as a parameter to allocate usage.

Propagation characteristics can change in time. These changes often happen on a

periodic basis being driven by some phenomenon. Day-night, seasonal and even sunspot

cycles can affect propagation phenomena. For example, these cycles will affect the electron

concentrations in the ionosphere thus affecting the height at which the ionosphere refracts

signals and the signal frequencies that can be refracted.

Table 1-1. The International Telecommunications Union – Radiocommunication sector band designations

Band Designation

Frequency range

Wavelength

Overall

Utilization

Antenna

Gains

Propagation

Modes

Coverage Susceptibility Predict-

ability

ELF (extremely low

frequency)

30 – 300 Hz

10,000 –

1,000 km

3 VF (voice frequencies) 300 – 3000 Hz 1,000 – 100 km

VLF (very low

frequency)

3 – 30 kHz 100 – 10 km High Low

Groundwave,

skywave

Up to

5000 nmi

Noise, skywave

multipath

High

5 LF (low frequency) 30 – 300 kHz 10 – 1 km High Low

Groundwave,

skywave

Up to

1000 nmi

Noise, skywave

multipath

High

MF (medium

frequency)

300 – 3 000 kHz 1 km – 100 m High Low

Groundwave,

skywave

Up to

1000 nmi

Noise, skywave

multipath

Medium

7 HF (high frequency) 3 – 30 MHz 100 – 10 m High Low-Med

Groundwave,

skywave

Worldwide

Noise, ionospheric

activity

Low

VHF (very high

frequency)

30 – 300 MHz 10 – 1 m

Med

–

High

Low-Med Freespace

Line-of-

Sight (LOS)

Terrain multipath High

UHF (ultra high

frequency)

300 – 3000 MHz 1m – 10 cm

Med

–

High

Low-High Freespace LOS Terrain multipath High

SHF (super high

frequency)

3 – 30 GHz 10 – 1 cm Medium

Med-

Very high

Freespace LOS

Weather, terrain

multipath

Medium

EHF (extremely high

frequency)

30 – 300 GHz 1 cm – 1 mm Low

High –

Very high

Freespace

Limited

LOS

Weather, gaseous

absorption

Medium

12 300 – 3000 GHz

1 mm – 100 µm

13 3 – 30 THz

100 – 10 µm

14 10 – 300 THz

10 – 1 µm

15 300 – 3000 THz

1 µm – 100 nm

16 3 – 30 PHz 100 – 10 nm

17 30 – 300 PHz 10 – 1 nm

18 300 – 3000 PHz 1 nm – 100 pm

, hertz (Hz) ; 10

, kilohertz (kHz); 10

, megahertz (MHz) ; 10

, gigahertz (GHz) ; 10

, terahertz (THz) ; 10

, petahertz (PHz) ;

, kilometer (km) ; 10

, meter (m) ; 10

-2

, centimeter (cm) ; 10

-3

, millimeter (mm) ; 10

-6

micrometer (µm) ; 10

-9

, nanometer (nm) ; 10

-12

, picometer (pm)

1.7 Frequency

Frequency affects the properties of electromagnetic radiation. These effects vary by the

magnitude of the frequency. To simplify the discussion of these effects, bands of frequencies

have been given designations and then properties have been associated with those

designations. There are numerous ways frequency bands have been designated. The

International Telecommunications Bureau Radio Sector designates bands as listed in

Table 1-1. Bands 4 through 11 are the RF bands that they regulate. There are other

approaches to designating frequency bands. During World War II certain radar bands were

given code words so engineers could talk about them without divulging their actual

frequency. They were deliberately non-sequential. Frequently, engineers will still use these

types of designations; however, there is ambiguity as to the exact frequency bands to which

they refer. Over the years, many different references have tried to define these designations,

but they differ. It is at a point where different companies have different designations peculiar

to themselves. From the standpoint of spectrum management, these designations are

obsolete; however, as recently as 2002, the IEEE published a standard for letter designation

of radar-frequency bands. These designations are listed in Table 1-2.

Table 1-2. Letter designations for radar frequency bands (IEEE Std 521 – 2002)

Band Frequency

HF 3 – 30 MHz

VHF 30 – 300 MHz

UHF 300 – 1000 MHz

L 1 – 2 GHz

S 2 – 4 GHz

C 4 – 8 GHz

X 8 – 12 GHz

Ku 12 – 18 GHz

K 18 – 27 GHz

Ka 27 – 40 GHz

V 40 – 75 GHz

W 75 – 110 GHz

mm 110 – 300 GHz

The carrier frequency of a signal affects the properties of the equipment used to generate,

transmit, and receive the signal, as well as the propagation properties of electromagnetic

waves. More detail follows on the impact of carrier frequency on electronics, antennas, and

propagation. Different frequencies are best for different applications.

1.7.1 Effect on Electronics

There are three aspects of electronics that are affected by frequency: carrier generation,

signal filtering, and circuit construction. The difficulty of building a stable signal generator

(i.e., the circuit that makes the carrier signal) or of a tight bandpass filter (i.e., the circuit that

isolates a band of frequencies in the spectrum) is proportional to frequency. A ±0.01% drift

in a 1 MHz carrier signal has a variation of 200 Hz, whereas the same drift in a 1 GHz carrier

signal would be 200 kHz—the bandwidth of 20 commercial AM channels or 1 commercial

FM channel. A measure of the quality of a bandpass filter is its Q, which is defined as the

filter’s center frequency divided by its bandwidth.

A filter that isolates a 10 kHz wide signal at 1 MHz has the same Q as a filter that isolates

a 10 MHz signal at 1 GHz.

Circuit construction is difficult at higher frequencies since components, i.e., wires, come

closer to the wavelength of the signals. At these relative sizes, circuit components can

become antennas and thus interfere with themselves and generate and transmit signals that

interfere with other receivers. At the other end, lower frequencies often require bigger

components, e.g., antennas, making them impractical for mobile applications.

Simply, as the frequency increases, so do the cost and complexity of building the

electronics. Also, it is not generally feasible to build radios that can operate in bands that are

substantially separated in frequency. Some new technologies are changing this, but

currently, most communications systems are designed to work in very specific bands of

frequencies and cannot be moved to others. Reassigning services to other bands will

normally involve replacing the radios currently providing that service.

Finally, systems are generally assigned to operate at higher frequency assignments if they

require greater bandwidths.

1.7.2 Effect on Antennas

There are many nuances associated with antenna design but all designs are frequency

dependent. The gain of antennas and in the case of directional antennas their beamwidth

are

Beamwidth is the effective angle over which an antenna can receive a signal.

dependent on their relative size compared to the wavelength of the signals they are trying to

receive. Higher frequency antennas can be made smaller for an equivalent gain and

beamwidth. High frequency losses (see Section 1.7.3) can be made-up in higher gain

antennas; however, if it is a dish or parabolic antenna, it will also have smaller beamwidth.

Smaller beamwidth can be either an advantage or disadvantage depending on the application.

For example, smaller beamwidths are harder to detect and provide greater directional

resolution in radar applications, but complicate the tracking necessary in aircraft telemetry

applications.

1.7.3 Effect on Propagation

In free space, i.e., outside the earth’s atmosphere in a vacuum, RF signals attenuate with

the square of frequency and the square of distance. The difference in signal power of two

signals at different frequencies at the same range can be determined by

⎛⎞

⎜⎟

⎝⎠

where we want to know the relative strength of the signal with frequency f

as compared to

the signal with frequency f

. For example, at the same range, a 400 MHz signal will be 100

times weaker than a 40 MHz signal. Similarly, the relative strength of a signal after

propagation can be determined by

⎛⎞

⎜⎟

⎝⎠

where we want to know the relative strength of a signal at distance d

compared to the

relative strength of this same signal at distance d

. For example, a signal will be 100 times

weaker at 10 meters from an antenna than at 1 meter from the antenna. The good news is

that it will only be 4 times weaker at 2 kilometers than at 1 kilometer.

In the atmosphere and near the earth’s surface, there are numerous other effects, all

frequency dependent, that change the range a signal propagates. Below are some of these

effects.

Absorption: Atmospheric gases, i.e., oxygen and water vapor, absorb signals. Figure 1-22

illustrates the specific attenuation that occurs because of this absorption. Again, higher

frequencies attenuate more.

Telemetry is the process of transmitting data collected on a remote object to a receiving station.

Foliage losses: Foliage scatters and attenuates signals. This type of attenuation increases

with frequency.

Building penetration: Building penetration decreases as frequency increases.

Seawater penetration: Radio waves penetrate seawater at Extremely low Frequency (ELF)

and to some degree at Very Low Frequency (VLF).

Figure 1-22. EM signal absorption by atmospheric gases

Ducting: A special condition that causes refraction, i.e., the bending of the wave in the

atmosphere. A skyward signal bends in the atmosphere and is redirected toward the earth

where it is reflected, and the effect repeats itself. This can lead to long range propagation

since there is less spreading of the wave. Ducting does not occur at higher frequencies since

the reflecting surface of the earth appears less smooth and scatters the signal, thus breaking

up the wave. Similarly, at low frequencies the sizes of the ducts will not accommodate the

wavelengths.

Ground wave propagation: Vertically polarized

waves at frequencies below 2 MHz can

propagate along the surface of earth. These types of waves induce currents on the earth’s

surface that enable the waves to propagate over the horizon and if conditions are suitable, to

propagate around the world. They propagate best where the earth’s surface conducts best,

like across the ocean. Their propagation is relatively unaffected by changing atmospheric

conditions. Ground waves are frequently used for ship-to-ship and ship-to-shore

communications.

Sky-wave propagation: Signals are reflected or refracted off the earth’s troposphere or

ionosphere allowing greater propagation of signals. This phenomenon affects the high

frequency (HF) band. Specific ranges of the signal depend on which layer of the atmosphere

acts on the signal. This varies with the time of day and some seasonal factors.

Earth-ionosphere waveguide: At frequencies below 30 kHz, both the earth and the

ionosphere behave as conducting mediums. Together they form two spherical shells that

guide waves within. Since electromagnetic waves do not spread out, there is much less

attenuation and thus they can propagate further.

There is a rich diversity in tradeoffs associated with frequency. Although higher

frequencies tend to attenuate more, this attenuation can actually be a feature in a system

where it is desirable to reuse the frequency.

1.8 Summary

In this section, we have provided a brief review of radio communications principles as

they apply to the use o f the RF spectrum. We have demonstrated that management of the

RF spectrum has three components: a frequency component, a spatial component, and a time

component. This provides the basic paradigm for spectrum management. The goal is to

prevent interference among users by separating them in spectrum, separating them in space,

Polarization of a radiated wave refers to the direction of the electric field vector of that wave. If the electric

field remains constant in a direction perpendicular to the surface of the earth then it is linearly and

vertically polarized. A long wire antenna that is perpendicular to the earth generates vertically polarized

waves.

or separating them in time. We have explained that performance of communications systems

varies by the band of frequencies in which they operate and the physical environment in

which they are employed.

Section 2

The History of Regulation

Spectrum management procedures have resulted from a series of needs that arose not

only from technological developments, but from commercial and social pressures. In this

section we provide a brief history of spectrum management that attempts to explain how the

existing spectrum management agencies came into existence and how they function and

interact with each other.

2.1 The Birth of Regulation

The first commercial use of radio, radiotelegraphy, occurred at the beginning of the 20

century. Its primary application was in maritime communication, where it was seen as a

significant advance in safe shipping and control of naval vessels. The state-of-the-art,

however, only allowed single use of the spectrum. Intense unregulated competition resulted

in interference, and worse, commercial restrictions on its free use. The Marconi Wireless

Telegraph Company was very aggressive in its efforts to create a monopoly. Its strategy was

to establish shore stations in the principal maritime countries. These stations were prohibited

from handling messages from ships that used equipment of a different manufacturer, thus

creating the incentive for ships to lease Marconi equipment. These ships, in turn, were also

restricted to communicating only with stations using Marconi equipment. Meanwhile, the

Navy was very concerned that it was forced to compete with commercial interests in

establishing communications stations for naval operations. The Navy became the vocal

proponent for national regulation advocating that they be the central authority for regulation.

Early in 1902, Prince Henry of Prussia attempted to send a message from his ship to

President Roosevelt thanking him after a visit to the United States. He was unable to send

the message because a Marconi equipment operator refused to transfer it from Slaby-Arco

equipment. This so infuriated the Prince that he brought the matter to the attention of his

brother, Kaiser Wilhelm. Shortly thereafter, the German government proposed an

international conference to consider an international convention for regulating maritime

communications.

This convention was held in August 1903 in Berlin with several European

countries and the U.S., in attendance. The convention ended with a proposed protocol that

would have required all stations to inter-communicate and to accept messages from any ship.

Great Britain and Italy, both in contractual arrangements with Marconi, did not concur, but

all delegates left the convention agreeing to submitting it to their respective governments and

to use it as the basis of a future convention tentatively scheduled for the next year.

Users of the German Telefunken equipment had the same restriction on its use as the Marconi equipment

operators.

2-1

The next conference, postponed until 1906 because of the Russo-Japanese War, was

again held in Berlin. At this conference, international participation increased three-fold. The

purpose of the conference was to adopt the protocol proposed in 1903. The United States

delegates took a leading role in this conference, reporting on experiments conducted by the

Navy to use stations of different manufacture. These reports emasculated the countering

argument put forth by the Marconi interests that systems of different manufacture could not

operate with each other effectively. This U.S. delegation also revealed evidence of

outrageous refusals by Marconi-equipped ships to relay information necessary for maritime

safety. These arguments placed the U.S. delegation in the lead for making the conference a

success, and just one month after convening, the delegates signed the documents embodying

its decisions. In addition to requiring all ships to intercommunicate and all shore stations to

accept messages from ships, the conference established an International Bureau at Berne,

Switzerland, for housing and distributing information concerning systems in use and the

wireless stations in each country. This organization is the origin of today’s International

Telecommunications Union Radiocommunication (ITU-R).

The competition between public and private interests in radio communications was no

less prevalent in American politics. Despite the leading role Americans played in getting the

agreement at the first radiotelegraph conference, it took until the dawn of the next

radiotelegraph conference for legislation to be passed. It was actually the impending

conference and the international sentiment against inviting the Americans that drove it to be

reconsidered. Then in April 1912, one of the greatest maritime disasters of all time

occurred—the sinking of the Titanic. The role radiotelegraphy played in that disaster

attracted the public’s attention, and the bill was quickly passed in July that same year. In

addition to ratifying the terms of the 1906 Berlin Conference, this act regulated the character

of emissions and transmission of distress calls, set aside frequencies for government use, and

placed licensing of wireless stations and operators under the Secretary of Commerce and

Labor.

The Third International Radio and Telegraph Conference met in the summer of 1912, in

London. The Titanic disaster further focused the attention of this conference on maritime

safety regulations. The U.S. delegation proposed most of these safety regulations. The

Conference adjourned with the proposed next meeting to be held in Washington in 1917.

Because of World War I, this convention was not held until 1927.

2.2 The Birth of Spectrum Management

Many advances in communications occurred during World War I, but none of these truly

challenged the adequacy of the existing agreements. It was the rise of broadcast radio in the

1920s that proved existing regulation to be inadequate. President Harding directed the

Secretary of Commerce, Herbert Hoover, to convene a conference of interested parties to

study the problem and to make recommendations to resolve it. That year, Hoover established

the Interdepartment Radio Advisory Committee (IRAC) to advise him in these matters. Four

2-2

national conferences were held between 1922 to 1925, and although substantive

recommendations were developed on how spectrum should be allocated, they were without

force of law. This came to a head in 1926 when Hoover entered an agreement with the

Canadian government to allow them exclusive use of six channels. Subsequently a station in

Chicago requested one of these channels. The Commerce Department denied their request,

but the station used it anyway. The government sued the station. A decision was rendered

shortly thereafter that the Secretary of Commerce had no power to refuse licenses to

reputable U.S. citizens. The decision removed any vestige of control the government had to

regulate spectrum use. This embarrassing situation at home and a pending international

conference (to be held in Washington) prompted Congress to pass the Radio Act of 1927 in

February of that year.

The Radio Act of 1927 created a five-member Federal Radio Commission (FRC) with

regulatory powers that gave it authority to license stations, allocate frequency bands to

services, assign frequencies to individual stations, and to control station power. It was

originally envisioned that they would accomplish their job in one year and then the licensing

authority would be returned to the Commerce Department. The political nature of assigning

spectrum to commercial interests kept Congress from approving the appointment of the

commissioners for over half a year, and the delay complicated the FRC’s actions. Congress

reluctantly renewed the FRC’s authority the next year. In the end, the FRC had the

undesirable task of reducing the number of commercial AM stations to a more manageable

number, forcing hundreds to surrender their license.

The Fourth International Radio Conference was held in Washington in October 1927.

This was the first international conference to produce regulations for the management of

frequency. In deference to countries where radio was a commercial venture, the regulations

were divided into two categories: general regulations and supplementary regulations. The

supplementary regulations contained rules of a managerial nature relating to the operation of

radio service and were not to be signed by countries where radio was a commercial venture

and, thus, not by the United States. The general regulations contained the articles that

allocated frequencies. This conference adopted frequency, as opposed to wavelength, as the

standard measurement allocation. Then, rather than making frequency allocations by

country, they allocated frequencies to specific service (e.g. fixed services, mobile services,

broadcast, amateur) thus allowing all nations equal rights to use the specified bands. The

regulations themselves were written in non-definitive terms that encouraged technological

advancement and gave governments the right to further regulate the use of spectrum. The

smooth running of this conference was largely due to the technical preparation that the

United States had done through its national conferences. The impact of this technical

preparation led to the creation of the International Technical Consulting Committee on Radio

Communications. Its purpose was to provide advice and opinions on technical questions of

communications submitted by nations and private interests. This committee advised the

2-3

International Berne Bureau of Communications, which then coordinated the issues with

member nations in preparation for succeeding conferences.

The Fifth and Sixth International Radio Conferences did not have as significant an

impact on the procedures used to manage spectrum as did the Fourth. However, there was

much modification to frequency management regulations to account for advances in the

state-of-the-art and to provide the mobile services that were necessary to accommodate

aviation. Each of these conferences, however, made contributions to the regulatory process.

The Fifth conference accomplished the unification of the international radiotelegraph and

telegraph conventions forming the ITU. The one development that came in preparation for

the Sixth conference in 1938 was the regional conferences that were held in preparation.

There was a North American conference, a Western Hemisphere conference, and several

European conferences all dealing with regional issues in spectrum management. Provisions

were then made to hold regional radio conferences in preparation for all subsequent

international conferences.

2.3 The Communications Act of 1934

The motivation for the Communications Act of 1934 was more to resolve the confusion

over which government agencies controlled the different parts of communications than it was

to deal with specific issues of frequency management. The Post Office Department, the

Interstate Commerce Commission (ICC), and the Department of State (DoS) regulated

telegraphic service. The ICC regulated telephone service. The FRC had authority over

broadcasting. The Communications Act of 1934 created the Federal Communications

Commission (FCC) as the single agency to manage these commercial activities. The FCC

was set-up with seven commissioners (later changed to five). The president appointed these

commissioners and designated one to be the chairman but not more than four commissioners

(later changed to three) could be from a single political party. The FCC, however, was made

part of the legislative, as opposed to executive branch of government, and reports to

Congress.

Also clearly delineated within this act was the separation of the responsibility of

managing frequencies used by government to the President. There was no guidance

concerning the organization to manage these tasks and the role remained within the

Department of Commerce. The IRAC, first created by Herbert Hoover in 1922, continued to

serve as the practical body to manage frequency use.

There have been some organizational changes in the FCC, the latest in 2002, and a series

of changes in the government agencies that manage government spectrum, but the basic

structure of a dual-headed management organization continues to serve the country. The

FCC manages spectrum for commercial, state, and local government interests; and the

Department of Commerce manages spectrum for federal government activities. The current

organizations of these agencies are presented in Section 5.

2-4

2.4 Maturing of International Regulation

The Seventh International Radio Conference did not occur until after World War II and

took place in Atlantic City in 1947. The significance of this conference is that it led to a

major reorganization of the ITU that, for the most part, still exists today. First and foremost

the ITU became a United Nations agency. Its headquarters was later moved from Berne to

Geneva. Second, through the leadership of the U. S., the International Frequency

Registration Board (IFRB) was created. The perceived limitation of previous regulations

was the ambiguity associated with assigning national versus international frequencies. The

general accepted practice was that any administration could assign a frequency to a station

under its jurisdiction so long as it did not cause harmful interference in the radio services of

other countries. If an assignment could cause interference on other countries then it should

be selected according to the table of frequency allocations and be selected to minimize

interference. These practices led to a perception that international communications had

priority in registration. Questions of interference could only be handled by the

administrations of the countries involved. With the increased use of radio frequencies and

the uncoordinated methods used by some administrations to manage frequency, there were

many conflicts. Additionally, the need to retain priori notification and to use dates that

determined precedence served as a disincentive to voluntarily move to avoid interference.

To resolve this situation, the U.S. delegates proposed the creation of the IFRB. Its essential

functions were:

1) To effect an orderly recording of frequency assignments to ensure their formal

international recognition, and

2) To furnish advice to the members of the Union concerning the maximum practicable

number of radio channels in those portions of the spectrum where harmful

international interference might occur.

These regulations effectively required all administrations, before taking action that could

result in harmful international interference, to notify the projected usage to the IFRB. The

IFRB would review these requests for conformity to the radio regulations and determine if

they would interfere with any previously recorded service. The IFRB would then either add

the new usage to the Master Frequency Register, giving it international protection from

harmful interference, or would notify the requestor that it was found to be unsatisfactory. It

is important to note that the IFRB database only contained frequency assignments with a

“global” reach. Nations thus report only HF broadcasting and non-military satellite

frequencies. The IFRB database was not a database of all uses of frequencies and most

national assignments were closely held.

2-5

2.5 The Formation of the National Telecommunications and Information

Administration (NTIA)

NTIA was created in 1978 as part of an Executive Branch reorganization. It transferred

and combined functions of the White House’s Office of Telecommunications Policy (OTP)

and the Commerce Department’s Office of Telecommunications. The OTP had been created

during the Nixon Administration to provide the President a direct hand in the regulation of

media. Its advisory function was placed in NTIA. The NTIA Organization Act of 1992

codified NTIA’s authority and organization. In addition to its frequency management role,

which will be described in detail later, NTIA has yielded information and positions that have

been important to legislation. Its NTIA Infrastructure Report (1991) proposed the

marketplace solutions to the problems created by technological change, specifically the

auctions used to manage wireless communications. A description of the current organization

of NTIA is found in Section 5.

2.6 Summary

This brief history of the creation of organizations to manage frequency spectrum has

attempted to provide the historical basis for the processes that exist today. History has

shown that it is in the interest of all users of spectrum to cooperate in its management;

however, management can frequently be manipulated to support private interests. Through

the creation of organizations and procedures, our government and the international

community have attempted to create a process that is both fair and efficient. Just as these

organizations have changed in the past because of the advancement of technology, they are

likely to change in the future.

2-6

Section 3

The Basics: Spectrum Allocation

The objective of this section is to describe how spectrum management is communicated.

It explains how allowed spectrum use is defined and provides definitions of a subset of the

terminology that is used to assign and regulate spectrum. Finally, it illustrates the current

allocation of frequency within the United States.

3.1 The Traditional Administrative Approach to Spectrum Management

Traditionally, spectrum management has been viewed as a system of frequency

allocations, allotments, and assignments. The entire spectrum is divided into frequency

bands called allocations. The allocations specify the allowed use of the frequencies in the

band. These uses are referred to as radio services (e.g., fixed, mobile, broadcasting,

radiolocation, radionavigation, amateur, satellite, radio astronomy, etc.).

These allocations

may then be further subdivided into allotments. Frequency channels are allotted within the

band in accordance with an agreed plan for use by one or more administrations in one or

more identified countries or geographic areas and under specified conditions. For example,

an allocation to the broadcasting service is subdivided into channel allotments for television

broadcasting in the Western Hemisphere. Allotments attempt to prevent interference among

users that are managed by different administrations. For example, one is the allotment of

channels in plans to avoid interference along borders of countries that are members of the

plan. There are separate allotment plans for maritime mobile, aeronautical mobile route

services, and certain satellite services where frequencies and orbit positions are included in

the allotment plan.

Finally, an assignment is a grant of authority or license to a specific user for a band of

frequencies or a radio frequency channel under specified conditions. Assignments are the

final subdivisions of spectrum. Some assignments are exclusive, meaning the licensee is

protected from interference. Other assignments are issued on a nonexclusive basis, requiring

the users to cooperate on an informal basis to avoid interference. Some bands are available

for specific uses without assignment, such as Citizen Band (CB) radio and the various

Industrial, Scientific, and Medical (ISM) bands.

In the United States, NTIA has authority to grant frequency assignments to government

agencies, while FCC grants authority to use radio frequencies or channels by issuing licenses

to private sector entities and local and state governments.

A definition of terms recognized by the ITU is provided in the Glossary.

3.2 Definitions (As Defined by the ITU Radio Regulations)

Administration: Any governmental department or service responsible for discharging the

obligations undertaken in the Constitution of the International Telecommunication

Union, in the Convention of the International Telecommunication Union and in the

Administrative Regulations.

Allocation (of a frequency band): Entry in the Table of Frequency Allocations of a given

frequency band for the purpose of its use by one or more terrestrial or space

radiocommunication services, or the radio astronomy service under specified conditions.

This term shall also be applied to the frequency band concerned.

Allotment (of a radio frequency or radio frequency channel): Entry of a designated

frequency channel in an agreed plan, adopted by a competent conference, for use by one

or more administrations for a terrestrial or space radiocommunication service. in one or

more identified countries or geographical areas, and under specified conditions.

Assignment (of a radio frequency or radio frequency channel): Authorization given by an

administration for a radio station to use a radio frequency or radio frequency channel

under specified conditions.

3.3 United States Frequency Allocations

Frequency bands are allocated primary and secondary services. Users of the primary

service have priority over the users of the secondary service. Users of secondary services are

usually required to operate with greater restrictions to avoid causing interference and must

accept interference from the primary users. Exceptions to allocations may also occur and

appear as footnotes. These footnotes allow uses of bands under specific conditions for other

services and users than listed as primary.

U.S. frequency allocations are divided further into government and non-government use.

Figure 3-1 illustrates the allocation of spectrum to services and to users in the U.S. and its

Possessions. Unique in this allocation is the subdivision of spectrum into red, green, and

black activities, delineating the portion of the spectrum where the primary use is exclusively

for non-government use, green; government use, red; and shared government and non-

government use, black. This has particular relevance in the current spectrum management

environment where Congress has and may further convert government bands to non-

government use. Current government exclusive allocations are listed in Table 3-1. (A large

version of Figure 3-1 is available at the following URL:

http://www.ntia.doc.gov/osmhome/allochrt.pdf.

Figure 3-1. Spectrum allocation

Table 3-1 contains the remaining bands where the government has exclusive primary status.

Many of these bands, however, allow civil use of the spectrum either in a secondary status or

a primary status through a footnote in the regulations. Table 3-2 lists the subset of bands

where there is no other permitted civil use of the frequency. Note that many of the

government’s higher frequency bands are also used for non-government purposes.

Table 3-1. Frequency bands where government has exclusive primary status

14-19.95 kHz 25.33-25.55 MHz 26.48-26.95 MHz 27.54-28.00 MHz

28.89-29.91 MHz 30-30.56 MHz 32-33 MHz 34-35 MHz

36-37 MHz 38.25-39 MHz 40-42 MHz 46.6-47 MHz

49.6-50 MHz 138-144MHz 150.05-150.8 MHz 157.0375-157.1875 MHz

162.0125-173.2 MHz

173.4-174 MHz 225-328.6 MHz 335.4-399.9 MHz

410.0-450.0 MHz

902-928 MHz

1.215-1.3 GHz 1.35-1.39 GHz

1.429-1.435 GHz 1.755-1.850 GHz 2.200-2.290 GHz 2.7-2.9 GHz

3.1-3.65 GHz 4.4-4.5 GHz 4.8-4.94 GHz 5.25-5.35 GHz

5.65-5.925 GHz

7.125-8.45 GHz 8.4-8.45 GHz 8.5-9.0 GHz

9.5-10.45 GHz 14.4-15.35 GHz 15.7-17.2 GHz 33.4-36 GHz

43.5-45.5 GHz

1. Exceptions in these bands allocate primary use to some non-government users.

These bands are also allotted for industrial, scientific, and medical (ISM) use.

Table 3-2. Frequency bands where the government is the exclusive user

14-19.95 kHz 2.0-2.065 MHz 25.33-25.55 MHz 26.48-26.95 MHz

27.54-28.00 MHz 28.89-28.91 MHz 30-30.56 MHz 32-33 MHz

34-35 MHz 36-37 MHz 38.25-39 MHz 40-42 MHz

46.6-47 MHz 49.6-50 MHz 138-144 MHz 150.05-150.8 MHz

157.0375-157.1875 MHz 162.0375-157.1875 MHz 163.2625–166.2375 MHz 166.2625-169.4125 MHz

169.5375-170.1375 MHz 170.1625-170.2125 MHz 170.3375-170.4125 MHz 170.4375-170-4625 MHz

170.4875-150.5625 MHz 170.5875-171.0125 MHz 171.1375-171.4125 MHz 171.4375-171.4625 MHz

171.4875-171.5625 MHz 171.5875-171.8125 MHz 171.9375-172.2125 MHz 172.2375-172.2625 MHz

172.2875-172.3625 MHz 172.3875-173.0625 MHz 173.0875-173.2000 MHz 173.4-174 MHz

225-328.6 MHz 335.4-399.9 MHz 410.0-412.6125 MHz 412.6375-412.6625 MHz

412.6875-412.7125 MHz 412.7375-412.7625 MHz 412-7875-420.0000 MHz 1.755-1.850 GHz

2.200-2.285 GHz 4.4-4.5 GHz 7.250-8.025 GHz 8.4-8.45 GHz

14.5-14.7145 GHz 43.5-45.5 GHz

This spectrum does not satisfy the full requirements of the Department of Defense

(DoD), so it uses many other bands either in a shared or secondary status. Appendix A

shows a full listing of DoD spectrum usage. Note that much of this spectrum is used on a

non-interference basis (NIB). Since there are separate allocations for government and non-

government uses, the DoD is automatically in a secondary status when it tries to use

spectrum in the non-government bands. This has relevance when the DoD wants to use

commercial equipment designed for non-government bands.

1.42

0.74

6.66

8.49

13.73

4.852.81

22.8218.58

30.64

93.71

96.44

70.5

72.92

55.62

20%

40%

60%

80%

100%

0-3.1 3.1-5.925 5.925 - 30 30 - 300 0 - 300

SHARED

NON-GOVT EXCLUSIVE

GOVT EXCLUSIVE

SPECTRUM ALLOCATION

FREQUENCY BANDS (GHz)

Figure 3-2. Allocation of spectrum to federal government and non-federal government

use as a percentage of bandwidth

Figures 3-2 through 3-4 illustrate three views of government use of spectrum. Figure 3-2

illustrates the portion of each band as a percentage of total bandwidth that is allocated to

federal government and non-federal government use. The government has the smallest

portion. Figure 3-3 illustrates the portion of the total number of assignments and licenses

that are found in each band. Clearly, the 0-3.1 GHz band is the most used spectrum. This

disproportionate use of the first 3.1 GHz of the 300 GHz of RF spectrum is an indication that

this 1% of the total RF spectrum is the most useful and the most coveted. Figure 3-4

illustrates how government assignments are distributed by government function. Although

national defense has the largest percentage of assignments, it still has fewer than half the

government assignments. This data was compiled using older databases and does not reflect

some of the more recent reallocations of spectrum. These reallocations decrease the

These charts were created using data compiled from the NTIA’s Frequency Management Record System

(FMRS) Allocation Table as of 01/29/97, the Government Master File (GMF) as of 07/25/2000, and the

FCC database (DB) as of 1993. This data does not reflect recent reductions in the Government allocations.

allocations for federal government exclusive use and the portion of the government exclusive

use spectrum used for national defense.

20%

40%

60%

80%

100%

0-3.1 3.1-5.925 5.925 - 30 30 - 300

GOVT ASSIGNMENTS

NON-GOVT LICENSES

FREQUENCY BANDS (GHz)

LOCATION OF ASSIGNMENTS AND LICENSES

93.02

95.57

1.17

0.43

5.71

2.66

0.10 0.12

Figure 3-3. Percentage of total number of assignments and licenses found in each band

39.46%

72.41%

46.61%

87.31%

40.30%

20%

40%

60%

80%

100%

0-3.1 3.1-5.925 5.925 - 30 30 - 300 0 - 300

Other Services

Transportation

Resources Mgt Control

Law Enforcement & Security

National Defense

FREQUENCY BANDS (GHz)

DISTRIBUTION OF ASSIGNMENTS TO

GOVERNMENT FUNCTIONS

260554* 3280*

16006* 268*

280108*

* Total number of assignments in the band

Figure 3-4. Percentage of total number of assignments to each federal government

function by band

3.4 Determining Allocations

The most current information concerning international allocations can be found in the

Radio Regulations (RR) that ITU-R Sector produces after each World Radiocommunication

Conference (WRC). The most current information concerning national allocations can be

found in the NTIA Manual of Regulations and Procedures for Federal Radio Frequency

Management, which is more commonly referred to as the Red Book. Figure 3-5 illustrates

the allocations as they are specified in the two documents. The RR identifies allocations by

region. These regions are shown in Figure 5-2. The U.S. is in Region 2. Both these

documents use the convention that primary service allocations are written in upper case and

secondary service allocations are written in lower case. Footnotes provide exceptions to

these allocations. The Red Book provides the same information on the allocation by region

found in the RR and also shows the allocations for federal government and non-federal

government use. Figure 3-5 shows that the band 162.0125-173.2 MHz is allocated to mobile

and fixed services on a primary basis for federal government use. No secondary services are

identified and no services are identified for non-federal government users. Thus, it shows

that the government has exclusive primary use of this band. However, footnotes can provide

exceptions and we see in the footnote US8 that certain non-federal government users may

use certain parts of this spectrum. The 173.2-174 MHz band allocation shows fixed service

has the primary status and land mobile service has secondary status. Both services are

exclusively for non-federal government use and there are no footnotes with exceptions. If

primary services were shown for both the federal government and the non-federal

government then the band would be considered shared.

Allocation to services

Region 1 Region 2 Region 3

156.8375-174

FIXED

MOBILE except aeronautical

mobile

156.8375-174

FIXED

MOBILE

5.226 5.229 5.226 5.230 5.231 5.232

5.231 Additional allocation: in Afghanistan, China and Pakistan, the band 167-174 MHz is also

allocated to the broadcasting service on a primary basis. The introduction of the broadcasting service into

this band shall be subject to agreement with the neighbouring countries in Region 3 whose services are

likely to be affected.

ITU-R Radio Regulations Table of Allocations

NTIA Red Book Table of Allocations

Figure 3-5. Example frequency allocation entries in the ITU-R Radio Regulations and

the NTIA Red Book

Section 4

Department of Defense Use of Spectrum and Threats to

that Use

The DoD is the largest government user of spectrum. It uses the radio spectrum from

ELF band through close to 100 GHz in the Extremely High Frequency (EHF) band.

Appendix A provides a detailed listing of current DoD use of various bands from Very High

Frequency (VHF) to EHF. As was pointed out in Section 1, different parts of the spectrum

are better suited for different purposes. In this section, we demonstrate that the DoD’s use of

spectrum is often based on these differences. The variety of missions and environments in

which the DoD uses spectrum requires this breadth of usage. We have also included brief

descriptions of activities that threaten to deny spectrum from DoD users. We attempt to

convey that losses in spectrum availability not only mean less spectrum overall, but also loss

of capability to provide certain services. These developments are made all the more critical

because DoD’s vision for future warfare hinges on the exploitation of communications and

sensor technologies that use the electromagnetic spectrum.

4.1 DoD Capabilities Derived from Use of Spectrum

Many capabilities that are essential to military operations are derived from the use of

spectrum. We attempt to broadly enumerate these capabilities below.

Strategic and Operational Communications: The DoD maintains a robust network of

terrestrial and satellite communications, spanning the spectrum from ELF to EHF, that

supports survivable command and control, worldwide, of U.S. military forces. DoD also

uses commercial satellite services to support many of these functions.

Tactical Communications: The military uses radio communications for tactical command

and control, dissemination of information for targeting, dissemination of information for

warning, and dissemination of information for situational awareness. These services are

achieved through the integrated use of multiple radio systems.

Control Functions: Radio links are used to control the functions of space systems and

unmanned air vehicles (UAVs).

Surveillance Data: Wide band data links are needed to transmit surveillance data obtained

by satellites, UAVs, and manned aircraft to analysis centers in real time. Use of such data has

been crucial for recent military operations.

Infrastructure Support: The military uses radio for various forms of infrastructure support.

These include Land Mobile Radio (LMR) that support various housekeeping and

4-1

administrative functions, air traffic control communications, and point-to-point links that are

used where it is not feasible to use wireline or cable links.

Radio Location: The military has many operational uses for radar systems. These include

long range early warning, surveillance, tracking of targets and other objects both to support

situation assessment and to support weapons system operations, target acquisition for

weapons systems, and precision mapping. Military forces use terrestrial beacon systems and

the GPS to locate forces and also use GPS and terrain following radars to support precision

targeting. Specialized radio beacon systems are used to identify friendly targets as friendly.

This function is needed to avoid fratricide.

Radio Navigation: The military uses multiple radio navigation systems to support

aeronautical and maritime operations. Some of these are operated by DoD, while others are

operated by other agencies. These include on-board radio altimeters. GPS is also used to

support navigation.

Test Support: Various general and specialized radio capabilities are needed to support the

testing of military systems. These include telemetry systems that download test data from

the systems under test to ground-based analysis facilities, weapons scoring systems, systems

that control unmanned targets, systems to terminate the flight of systems under test if they

threaten public safety, and radio location systems that track the positions of test participants.

Training Support: Specialized radio systems are used to support training operations. These

include air combat training systems and a field instrumentation system that add realism to

training operations and support performance assessments.

Troop Morale: The military operates a Family Radio Service and television broadcast

stations to maintain morale.

The DoD’s vision for future warfare hinges on the ability to sense the situation and to

move information. These capabilities are contingent on the availability of spectrum. Just as

the commercial demand for spectrum is increasing, so too is the military’s. Loss of spectrum

not only means a reduced capability when it happens, but it may also mean that a future

capability may not be exploitable.

4.2 Some Salient Factors

The basic factors that affect radio services are frequency, its wavelength, and available

bandwidth. A description of these tradeoffs was presented in Section 1. Here, we list

considerations that are important to DoD uses of the spectrum.

• At low frequency (LF) and below electric charges in the upper atmosphere reflect radio

waves to form an earth-ionosphere waveguide (see Section 1.7.3).

4-2

• Radio waves penetrate seawater at ELF and to some extent at VLF. These frequencies

are required for submarine communications

• At High Frequency (HF), radio waves are refracted off the electrically charged

ionosphere, thus allowing them to propagate long ranges. Prior to communications

satellites, HF (also known as short wave) was the only means of providing long-distance

communications.

• Propagation is limited to line-of-sight for frequencies above HF.

• Atmospheric absorption increases with frequency and ultimately prevents even line of-

sight propagation beyond short distance. Figure 1-22 illustrates atmospheric absorption’s

dependence on frequency.

• Rain attenuates signals even more, especially at SHF and EHF.

• Foliage attenuation is extreme for frequencies starting at UHF and is more severe as

frequency increases. Long range communications at these frequencies require using

higher altitude antennas. For terrestrial communications it requires mounting antennas

on tall masts that can extend above foliage for line-of-sight communications. These

antennas tend to be immobile and may compromise the location of users.

• Hardware, historically, has been developed for lower frequencies first, and later

developed for higher frequencies. Priority of communications service, rather than best

use of spectrum, has been the driving factor in frequency assignments. Some services

occupy lower frequencies since they were the first frequencies available for the service,

not because they were the preferred frequency for the service.

• Wavelength affects the ability of a signal to propagate around or through an obstacle. If

the dimensions of the obstruction are much smaller than a signal’s wavelength, then that

signal can more easily propagate around or through the obstruction.

• When wavelength and obstruction dimensions are comparable, then the wave partially

propagates around the obstruction.

• The wavelength of the radar signals must be much smaller than the dimensions of targets

in order for the target details to be detected.

• The ability of radar to resolve details is also proportional to the bandwidth of the radar

signal.

• Antenna sizes are proportional to the wavelength of signals. As frequencies decrease,

larger antennas are required. It is impractical to put large lower frequency antennas on

mobile platforms.

4-3

• The amount of information that can be transmitted by a communications link is

proportional to the bandwidth that is available to that link. Therefore, with conventional

designs, systems that convey large amounts of information need to operate at higher

frequencies.

• Many operational military systems spread signals over bandwidths that are much wider

than is needed to convey information in order to decrease vulnerability to enemy

jamming or to detection and intercept (see Section 7.4.3). This need for protection

against enemy operations leads to a requirement for much more bandwidth than would be

required to just transmit the same amount of information.

• Achieving efficiency by minimizing the bandwidth used for a service has a

corresponding decrease in reliability, as these signals are more easily detected,

intercepted, and disrupted. They are also more susceptible to noise.

4.3 System Tradeoffs

It is clear from the foregoing considerations that radio system designers need to consider

and trade-off among a large number of factors. Also, it is clear from Appendix A, that the

DoD makes use of a large, varied set of radio services. DoD uses bands throughout the radio

spectrum, as well as spectrum in the lower VHF and the EHF bands which are not

specifically allocated. Communications systems that operate at the lowest frequencies are

used for reliable communications with ships and submarines at sea. However, since the

available bandwidth is low, those systems provide only low data rate messaging. The next

higher frequency bands support both voice and moderate data rate messaging. Appendix A

details DoD spectrum use between 30 MHz to 100 GHz. We see that standard

communications radios generally operate in the VHF and UHF bands, while fixed and

mobile systems that require higher data transfer rates generally operate between 1.3 and 5.0

GHz , with fixed systems operating up to 8.5 GHz. Some terrestrial systems operate at

higher frequencies, but generally, the higher frequencies are used for satellite

communications. The links between satellites and the surface go only a few miles through

the atmosphere, so they are not affected by atmospheric absorption to the same extent as

long-range terrestrial links. Critical command and control facilities and platforms contain a

suite of communications systems that operate in different areas of the spectrum and use

satellite, terrestrial long-range, and terrestrial line-of-sight modes in order to ensure that they

are able to maintain communications with command authorities and with the forces by at

least some means.

Radar designers also need to consider various tradeoffs. Long-range detection radar

systems operate at lower frequencies to take advantage of lower propagation losses. Radars

that resolve details of targets require the use of higher frequencies for two reasons. First, in

order for a signal to resolve details its wavelength must be smaller than the detail it is trying

to resolve. Second, radar antenna directionality is a function of the ratio of the wavelength to

4-4

the antenna size. The smaller wavelengths of higher frequencies enable the use of smaller

antennas to get the desired directionality. The tradeoff for better resolution is shorter radar

range. HF band radar systems provide over-the-horizon detection capability. Long range

land-based radar systems operate in the 1.2-1.4 GHz range. Because of their long

wavelengths, these radar systems cannot resolve details of detected objects or track their

positions precisely. Therefore, such radar systems provide long-range early warning of the

presence of objects. Many target acquisition and tracking radar systems operate in bands in

the 8.5-14 GHz range. The wavelength at 10 GHz is 3 cm, or about one inch, thus radar

systems at this frequency can resolve relatively small details. At this same frequency, an

antenna, about a half meter in size, can resolve direction to a few degrees. These radar

systems usually operate over shorter ranges, due to propagation losses. There are exceptions,

however. Some high-power space surveillance radar systems and experimental missile

defense radar systems operate in these bands. Radar systems that operate in bands between

3-6 GHz provide a mix of long-range and tracking capabilities. In general, tradoffs between

hardware capabilities, antenna sizes, and detection and tracking characteristics make this the

lowest frequency band for airborne and shipborne applications. However, some airborne and

shipborne radar systems do operate in the UHF band. Radar systems that operate in the 15-

35 GHz band are used for short-range precision functions such as terrain-following and

mapping. Experimental research on advance radar techniques is being conducted at higher

frequencies, in the EHF band.

DoD also operates radionavigation systems and uses radionavigation systems that are

operated by other agencies. In particular, DoD provides GPS services using three

frequencies within the 1.1-1.6 GHz band. It operates precision aircraft approach radar

systems in the 9.0-9.2 GHz band, and tactical aircraft landing systems around 15.5 GHz.

These are basically high-resolution, short-range radar systems.

4.4 Spectrum Losses and Restrictions

The current transformation of the armed forces to Network Centric Warfare is dependent

on the availability of additional communications capabilities. Appendix A explicitly

identifies many spectrum bands whose use is expected to increase. Concurrently, the civil

world has discovered the profitability of radio communications. Since these civil services

also need to use large amounts of spectrum, there has been much pressure for the DoD to

share spectrum where feasible and to surrender spectrum for use by those new services where

sharing is not practical. This section reviews various attempts to restrict DoD access to the

radio spectrum and discusses their implications and the measures that have been taken or that

could be taken to ensure that DoD meets its needs for radio spectrum.

4.4.1 Low Power Unlicensed Devices

Under Part 15 of the FCC regulations, low power devices that meet various conditions

are permitted to operate without a license in spectrum bands that are not allocated to critical

4-5

safety services. Many of these devices, including such familiar items as garage door

openers, cordless phones, and baby monitors, operate in bands that are allocated on a primary

basis to military use. Under Part 15, such devices are obliged to accept interference from

users that have proper assignments in that band. Despite this regulatory priority, when users

of such devices have complained about interference from properly assigned military users,

those military users have been directed to modify their operations in order to mitigate such

interference.

This situation may help explain the generally negative reaction to band-sharing

proposals, even when analysis suggests that such sharing would be feasible. If DoD users

are obliged to avoid interference when they have regulatory priority, their position would be

even less secure when the non-government parties that experience interference have equal

status in a band.

4.4.2 General Considerations

In the past decade, many new commercial wireless services have been under

development. These new services require spectrum in order to operate. Most notable among

these are satellite communications and audio broadcast systems, various terrestrial broadband

mobile systems, and ultra wideband (UWB) sensor and communications systems. Based on

their own tradeoffs, most of these systems look for allocations in the 1-4 GHz range, with

some short range systems going up to 6 GHz. However, these bands are already allocated

and heavily used, so allocating spectrum for them to use will necessitate displacing existing

users. Since it is politically more practical to displace government users than to displace

commercial users, government users, specifically DoD, users are especially vulnerable.

Remember, the DoD is the predominant user of government spectrum. In the present and

future, proponents of new technologies are likely to seek to share with or to displace

government users. They will seek to obtain spectrum for their systems through domestic

political and public relations activities. Additionally, many of them may seek allocations

through the ITU. WRC

decisions on allocations have binding treaty status. Moreover, once

a service is allocated in some band by an international body, proponents can readily maintain

that it would be to the advantage of the U.S. to follow the rest of the world.

During the 1990’s, it was recognized that spectrum is a valuable resource and that the

government could obtain revenue by auctioning spectrum that was allocated to support

government activities. Under the Omnibus Budget Reconciliation Act of 1993 (OBRA 93),

102 MHz of spectrum was reallocated from exclusive government use to exclusive non-

government use, and another 133 MHz of spectrum was allocated to mixed government/non-

government use. This reallocation, which affected a number of bands between 1390 and

4685 MHz, affected a large number of DoD operations. In 1997, through the Balanced

This name has been used since 1995; prior to that the name was World Administrative Radio Conference.

4-6

Budget Act of 1997 (BBA 97), 20 MHz of remaining government spectrum was reallocated.

However, it was soon realized that auctions did not meet revenue estimates and that

government operations had been adversely affected by these reallocations. As a

consequence, the 1999 National Defense Authorization Act (NDAA) required reimbursement

to government users for costs related to 1997 and later reallocations. The 2000 NDAA

returned 8 MHz to government use. It also directed that no DoD systems be displaced from

their bands until the Secretaries of Defense and Commerce and the Chairman of the Joint

Chiefs of Staff certify that alternative frequency band(s) are available to retain the essential

military capability that would be otherwise lost.

4.4.3 Some Specific Cases of Spectrum Loss

Digital Audio Broadcast (DAB): The 1992 World Administrative Radiocommunication

Conference (WARC) allocated the 1452-1492 MHz band generally worldwide for satellite

and terrestrial DAB. This is in the middle of a band that is used in the U.S. for aeronautical

flight test telemetry. U.S. telemetry users objected to any loss of this band. Consequently,

the U.S. originally allocated the 2310-2360 MHz band to satellite DAB. This band had also

been used for aeronautical telemetry. Subsequently, half of that band was allocated to other

non-government services. As a result, U.S. aeronautical telemetry users have lost the use of

50 MHz of much needed spectrum.

The WorldSpace Corporation has proposed to launch a satellite in geosynchronous orbit

to provide DAB service to the Western Hemisphere south of the U.S. border. However, in its

initial design, the radiation from this satellite would have interfered with aeronautical

telemetry at many U.S. test ranges. Initially, WorldSpace attempted to maintain that no

interference would ensue. Subsequently, following substantial efforts by various DoD

organizations to assess this issue, WorldSpace agreed to modify the satellite radiation pattern

to conform to requirements of what was then a draft, and is now an accepted, ITU

recommendation on coordinating aeronautical telemetry and geosynchronous broadcast and

communciations satellites. At this time, there is at least one proposal to launch a

constellation of non-geosynchronous DAB satellites to serve Europe. It is not clear what

standards would be used to coordinate this constellation with aeronautical telemetry, since

there are no existing standards for coordination with non-geosynchronous satellites.

Fixed Wireless Access (FWA): Before 1979, there was a primary allocation to

Radiolocation in parts of the world, including the Western Hemisphere, Eastern Asia, and the

Pacific Basin in the 3400-3700 MHz band. The 1979 WARC removed this allocation and

urged governments to remove radar systems from this band by 1985. Nevertheless, the U.S.

operates major defense radar systems in the 3400-3650 MHz band. These include the

Airborne Warning and Control System (AWACS) radar, key naval radar systems, and a

beacon system that maintains flight formation and locates parachute drop sites. Outside of

the U.S., this band is allocated to the Fixed Service and is used by FWA wireless telephone

systems. Recently, vendors of these systems attempted to introduce FWA systems into this

4-7

band on a shared basis with military radar systems. However, DoD was able to demonstrate

that it was not practical to share this band. The FCC dismissed a proposal for reallocation

without prejudice. This does not mean that this issue will not be raised again at some later

time.

Third Generation (3G) Mobile Telecommunications: The 3G systems are envisioned as

being follow-on systems to cell phones that would support high-speed data transfer in

addition to voice. Such systems could provide streaming video, teleconferencing, and

Internet access to vehicle passengers, pedestrians, and occupants of office buildings who are

away from their desks. WARC 92 recommended that certain bands be set aside for 3G, then

known as International Mobile Telecommunications 2000 (IMT-2000). Many nations have

dedicated those bands to 3G communications, but, in the U.S., those bands had already been

allocated to other non-government services. WRC 2000 recommended that some additional

bands, including the 1710-1885 MHz band, be considered for use by 3G services. However,

it is clear from Appendix A that the 1755-1850 MHz band supports many vital DoD services

and that the DoD also uses the 1710-1755 MHz band at various protected sites. An NTIA

study determined that the DoD needed to continue using these bands and that it was not

feasible for the DoD systems that are already in these bands to share them with 3G systems.

A follow-on study proposed that the 1710-1755 MHz band be paired with another band that

is allocated to various non-government services and that DoD systems be cleared from this

band except at two protected sites. This proposal was accepted in 2002.

Radio Local Area Networks (RLANs): RLANs are unlicensed short-range wireless

networks that provide the same services that are now provided by wired LANs. WRC 2003

allocated bands in the 5-6 GHz range for RLAN services on a global basis. One of these

bands is allocated worldwide for radiolocation and is used by DoD antiaircraft and missile

defense systems and by instrumentation radar systems on test ranges. The U.S. intends to

implement this allocation for use by the Unlicensed National Information Infrastructure (U-

NII), using the appropriate Wireless Fidelity (WiFi) standard. The implications of this U-NII

allocation are uncertain. Individual RLAN installations would probably not ordinarily

interfere with radar systems, but uncontrolled proliferation of such systems could increase

background noise to a level that interferes with radar operations.

Operators of radar systems, worldwide, have been concerned by this potential for

interference. In order to mitigate potential interference to radar systems, WRC 2003 required

that RLAN systems implement dynamic frequency selection (DFS) techniques that would

cause them to avoid transmitting on any channel that is being used by a radar, as well as

implement transmitter power control (TPC) to ensure that RLAN systems emit no more

power than is necessary to maintain connectivity. Since the DoD recently committed itself to

the concept of sharing spectrum wherever it can do so without compromising national

security, it has agreed to this U-NII allocation provided adequate DFS is implemented. An

ITU study group has published draft DFS performance recommendations and the FCC is also

considering DFS performance requirements. However, all parties recognize that further

4-8

studies, based on practical experience, are needed to ensure that DFS can be implemented to

adequately protect radar systems from interference by RLAN systems.

Mobile Satellite Service (MSS): The MSS supports satellite communications by and to

mobile users on earth. For a number of years, some MSS operators have been looking for an

additional international allocation in the 1.5-1.6 GHz range and this has been an agenda item

for recent WRCs. Initially, those operators attempted to obtain an allocation in a band

adjacent to one used by GPS, but various studies demonstrated that MSS would cause

unacceptable interference to the GPS signal. As a result, those MSS operators focused on the

1518-1525 MHz band. We see from Appendix A that, in the U.S., this is part of a band that

is dedicated to use by aeronautical telemetry. Before WRC 2003, this band could be used in

the Western Hemisphere outside of the U.S. by MSS, but there is no such use now.

Recently, WRC 2003 allocated this band worldwide to MSS. There are two potential

problems with this reallocation. The direct problem is that MSS systems that are designed to

serve users outside the Western Hemisphere could interfere with U.S. telemetry, particularly

along the East Coast. The indirect problem is that use of this band outside the Western

Hemisphere could encourage its use within that hemisphere as well. This could lead to the

same type of problem that was encountered with the WorldSpace DAB satellite.

Coordination between telemetry and MSS is subject to the same considerations as is

coordination with DAB satellites. The recommendation that was used to coordinate the

WorldSpace system applies to geosynchronous MSS satellites, but there are no accepted

criteria for coordination with non-geosynchronous MSS satellites.

4.4.4 Ultra Wideband

DoD is in an ambiguous position with regard to impulse Ultra Wideband (UWB). On

one hand, systems that can provide vital military services, such as ground and wall

penetrating radar and communications that are difficult to intercept, operate in this mode. On

the other hand, since such systems spread their signal over those lower frequency bands that

support some of the most basic radio services, the uncontrolled proliferation of unlicensed

UWB systems could create a noise background that could interfere with existing uses. NTIA

studies have demonstrated that GPS is particularly vulnerable to UWB transmissions, and

that other radionavigation systems, as well as satellite earth stations, are also vulnerable.

Therefore, some restriction on UWB devices is needed. The FCC has authorized use of these

devices on a limited basis and the possibility of easing those restrictions is still under study.

The use of UWB signals that are modulated onto carrier frequencies that lie toward the

higher end of the radio spectrum should be much less of a problem, since there are fewer

users at such frequencies and since the atmospheric absorption at extremely high frequencies

limits the effective range of any signal.

4-9

4.4.5 Public Sector Challenges

Although most challenges to DoD use of spectrum come from the private sector, the

Department receives challenges from the public sector as well. For example, state and local

government operators of public safety systems need more spectrum to support their

communications systems. Since it is easier to displace federal government users than it is to

displace private users, there has been pressure to reallocate some government spectrum to

use by public safety systems (see Section 4.6.2).

4.4.6 Government Coexistence Challenges

DoD shares spectrum with other Federal agencies and must therefore coordinate with

those agencies. A prime example of coordination for spectrum access, that is required both

within the U.S. and internationally, is the use of the Joint Tactical Information Distribution

System (JTIDS)/Multifunctional Information Distribution System (MIDS) in the frequency

band (960-1215 MHz) that is allocated to the Aeronautical Radionavigation Service (ARNS).

This frequency band, which in the U.S. is a shared band, is used primarily for civil aviation

and safety air traffic control systems. Coordination between the DoD, NTIA, FCC, and the

Federal Aviation Administration (FAA) or the equivalent agencies in each sovereign nation,

is required. NTIA stipulates the conditions under which the DoD can operate the system in

the United States and its Possessions (US&P). As the JTIDS/MIDS has been determined by

the NTIA to provide mainly non-ARNS services, it is authorized to operate, within the

US&P, in the frequency band via a footnote to the U.S. Table of Frequency Allocations, with

the condition that harmful interference not be caused to the ARNS. Such an operational

status in the band requires that conditions and restrictions be placed in the JTIDS/MIDS

Spectrum Support Certification to preclude interference and that the design of the terminals

be certified by NTIA as operating under compatible conditions.

Over the years, the attainment of a spectrum support certification and the certification of

terminals has been very challenging as the FAA and NTIA have insisted on very strict

standards, and the FAA has had its own plans for new systems in the frequency band. An

Electromagnetic Compatibility (EMC) Test Program was initiated in the 1970s and

completed in 1999. Data has been taken and operations have occurred for over 25 years

without an incident of reported interference. A spectrum support certification with

conditions that would support the required levels of DoD training requirements is scheduled

to be completed in the near future.

In 2002, the Department of Transportation (DoT) (mainly the FAA) and the DoD made

agreements for the long term sharing of the frequency band. DoD would agree to build in a

capability to clear a portion of the band in exchange for the following:

1) DoT/FAA would procure systems above 1030 MHz to be compatible with

JTIDS/MIDS;

2) DoT support for some sort of recognition of JTIDS/MIDS in the frequency band;

4-10

3) DoT support for a JTIDS/MIDS spectrum support certification and a US&P

frequency assignment that would meet DoD training requirements;

4) DoT support for a process whereby DoD would self certify the EMC features of their

JTIDS transceivers (a.k.a. Link-16 terminals).

As part of their agreement, DoD will ensure that by 2020, all Link-16 terminals are

capable of re-mapping frequencies from below 1030 MHz to the sub-band above 1030 MHz.

DoD will use this capability as required within the US&P to prevent harmful interference to

aviation systems implemented below 1030 MHz that are approved by NTIA. This capability

would be used to remap the minimum number of frequencies to promote compatibility as

determined by the NTIA.

4.5 Maintenance of Spectrum Capability

In the face of growing needs, coupled with spectrum losses, what do we need to do to

ensure that sufficient spectrum is available? One approach is to use alternate means, where

feasible. For example, we should consider replacing wireless links between fixed sites with

copper or fiber optic cable, and we should also consider laser communications.

In general, however, such alternatives will not be practical and we will need to consider

what can be done to most effectively use the available radio spectrum. No single approach

will suffice. Section 7 discusses a number of approaches, including new modulation

techniques that better confine signals within their assigned bands, the use of antennas that

direct signals to their intended receivers, and various techniques that opportunistically use

inactive radio channels.

4.6 DoD Use of Spectrum in the United States and its Possessions (US&P)

DoD makes extensive use of spectrum within US&P. Uses include training operations,

facility operations, test and evaluation (T&E), access to home bases, North American Air

Defense, and, in the last year, Homeland Security. Spectrum losses and restrictions, together

with the need for more spectrum to support operations, have lead to a number of difficulties.

The magnitude of these difficulties will only increase unless we are able to improve our

utilization of spectrum.

The following subsections address test and training issues; operation of posts, camps,

stations, and ports; and military operations issues. The final section covers the overarching

issue of negotiating the use of this same spectrum with other nations when its use is near our

nation’s borders.

4.6.1 Test and Training

The U.S. armed forces must train in the same manner that they will actually fight in order

to ensure that they are properly prepared for any contingency. The Joint Forces Command

4-11

estimates that 80 percent of this training takes place within the Continental United States

(CONUS) or within 100 miles of its coastline. Most of the major test ranges are located on

the US&P. However, limits on allocated spectrum and various restrictions on the use of

spectrum impair their ability to conduct realistic training. In addition, comprehensive testing

is needed to ensure that military systems are capable of performing their missions. Testing

requires the support of radars, telemetry, and other data transfer systems. Test capabilities

have been adversely impacted by loss of spectrum, as well as the inability to find more

spectrum for ever increasing data transfer requirements. Some specific cases of past and

potential future spectrum losses that impact test and evaluation were discussed in Section

4.3. Certain issues deserve special note.

Many major test and training ranges are located in the Southwest U.S., near the

Mexican border. Currently, there is no protection from interference from Mexico.

Expected future agreements could result in protection for half the spectrum in bands

that are subject to agreement, and loss of use of the remainder of such bands. Many

major test and training facilities lie within the sharing zone for terrestrial systems.

Airborne systems that operate within line-of-sight of the Mexican side of the sharing

zone would also be affected. This could affect operation of test and training ranges

that lie several hundred miles north of the border.

•

Use of electronic attack systems that intentionally jam radio frequencies is extremely

restricted within the US&P. Such jamming is used to defeat targeting by enemy

weapons systems and to disrupt enemy communications. Realistic training requires

that the armed forces train with these systems the way they would be used in actual

operations but they cannot do it because of these restrictions. The armed forces also

need to test their systems in a realistic jamming environment in order to evaluate

system performance. Because of these restrictions, for example, the Marines are

forced to conduct training operations using the EA-6B “Prowler,” the primary

airborne electronic attack system, at least 150 miles offshore. This requirement

impairs crew safety, since the aircraft must operate beyond the range of immediate

Search and Rescue capabilities. If a band is exclusively allocated to military use, it is

more feasible to conduct realistic electronic attack operations against systems in this

band. This was one consideration in the FWA proceeding that was discussed in

Section 4.3.

Restricting DoD systems to a limited number of bands has led to increased

interference between different systems that are needed to support a given operation.

For example, the Marine Corps has identified interference between their Pioneer

Unmanned Air Vehicle (UAV) and their AN/TRC-170 Microwave Radio Terminals,

which operate in the same relatively narrow band. Operations require the

simultaneous employment of both systems. This has proved to be a difficult

undertaking. In general, because of limitations in the availability of radio spectrum,

new systems must be designed so that there is no interference between the new

4-12

system and existing systems that operate in the selected band. This strains

technology and increases system cost.

Some ranges deploy key legacy systems that cannot readily be changed. For

example, the Marine Corps has established a need to protect legacy systems operating

in the 1710-1755 MHz at their Yuma and Cherry Point Air Stations. As a

consequence, protection of these sites was maintained in the 3G reallocation that was

discussed in Section 4.4.3.

•

Range support systems have been particularly vulnerable to reallocation. A

significant amount of spectrum that was previously allocated to range telemetry has

been lost. If the proposed reallocation of the 1755-1850 MHz to 3G had taken place,

then Air Combat Training Systems that support realistic air combat training and the

evaluation of combat performance would have had to find new spectrum. Use of

Flight Termination Systems, which are used to terminate the flight of missiles,

drones, and other unmanned aircraft that deviate from their proper flight path on test

ranges, could have been adversely affected by bilateral agreements with Mexico.

Due to the lack of government-allocated spectrum that was suitable for their

purposes, some training systems were designed to operate in non-government bands

on a non-interference basis. They would, for example, operate on television (TV)

channels that were not assigned for use in the vicinity of their range. However, the

assignment of additional bands to support the introduction of digital TV and the

expansion of other commercial services into remote areas negates this approach.

4.6.2 Posts, Camps, Stations, and Ports

Posts, camps, stations, and ports can be viewed as small cities that use spectrum for daily

operations in addition to their training, testing, and military operations. The additional uses

of spectrum support administration, safety, and security functions. The bands that are

available for these uses are 138-144 MHz, 380-400 MHz, and 406-420 MHz. Additionally,

the Corps of Engineers uses the 162-174 MHz band for their operations nationwide.

Currently, these bands are threatened with encroachment from the bands allotted to state and

local public safety, which include the 150.8-162 MHz and the 450-470 MHz bands. The

proximity of the 138-144 MHz and the 162-174 MHz government bands to the first public

safety band leaves them vulnerable to suggestions for extending the public safety band. The

380-400 MHz and 406-420 MHz bands are similarly threatened. The predominant land

mobile radio that is used for state and local public safety in the 450-470 MHz band is tunable

down to 380 MHz. Thus, the 380-400 MHz and 406-420 MHz bands can be subsumed by

public safety radios with minimum infrastructure costs.

4-13

4.6.3 Military Operations

Several naval ship radars operate in a band that is adjacent to a satellite downlink band.

There have been a number of reports of adjacent band interference with satellite

communications systems and with satellite TV. Generally, interference has been attributed

to poorly designed receivers that do not filter out signals that lie in the radar band. In

general, however, since radars transmit high power and satellite earth stations are very

sensitive, the potential for adjacent band interference exists even for well-designed receivers.

As previously noted in Section 4.4.1, many low power unlicensed devices operate in

military bands. Such devices operating in the vicinity of military bases often experience

interference. In addition, devices that are used in seaports are vulnerable to interference

when naval vessels are in port.

AWACS aircraft radars have been used for surveillance in support of North American

Air Defense and are now also used in support of Homeland Defense. If, as noted in Section

4.4.3, FWA operations had been allocated to share a band with AWACS radar, as proposed,

it would have been difficult to operate AWACS without the potential for interference. Since

the issue of using this band for the FWA may be raised again it is important that those

making decisions on the allocation of spectrum are aware of its significance in Homeland

Defense.

4.6.4 Coordination with Neighboring Countries

Spectrum on border regions must be shared with neighboring countries. Many

restrictions are placed on DoD use of spectrum in these regions. The following discussions

identify the more current issues that pertain to Canada and Mexico.

Canada: There have been recent discussions between the DoD and the Canadian

government on the introduction of FWA systems into Canada. These systems have already

been licensed in rural areas, and the Canadian government proposes to auction spectrum for

use by FWA systems in urban areas in the near future. There is a potential for interference

with AWACS, not only in border areas but also where AWACS is used in Canadian airspace

for North American air defense. There is also a potential for interference between Canadian

FWA in coastal areas and U.S. naval radar systems that operate at sea and in border waters.

As a result of these discussions, the Canadian authorities structured their allocation to

minimize potential interference with AWACS and also worked with DoD to develop

information on potential interference to FWA that could be provided to potential bidders at

the Canadian auction. Previously, the U.S. had worked with Canadian authorities to

coordinate between Canadian terrestrial DAB and U.S. aeronautical telemetry in border

areas. Coordination with Canada is carried out through a bilateral agreement that covers

government and non-government terrestrial radio services above 30 MHz.

4-14

Mexico: The U.S. is in the process of coordinating with Mexico on sharing the use of

various VHF and UHF bands in the border region. There are many DoD test and training

installations in the Southwest in the neighborhood of the Mexican border. As we see in

Appendix A, DoD makes substantial use of these bands for operational and support

communications and for radar systems, so that sharing these bands will have a major impact

on test and training operations. In particular, airborne operations within several hundred

miles of the border could be affected.

4.7 DoD Use of Spectrum Outside the US&P

The DoD uses spectrum worldwide. The allotments and assignments within the US&P

only apply to the US&P. This has three ramifications. First, before the DoD can use

spectrum worldwide, its use must be coordinated with all countries that will be affected.

Second, equipment must be developed to operate on the potential assignments that are or will

be available worldwide. Third, the DoD must ensure that their requirements receive proper

attention at WRCs and before ITU study groups. The following subsections elaborate on the

first two ramifications. The procedures of international regulation and DoD participation in

processes are discussed in Sections 5 and 6.

4.7.1 Host Nation Support

U.S. military forces are stationed in foreign countries around the world. These forces

must operate their radio systems in accordance with the laws, regulations, and allocations of

the host nations. Since no other country maintains a military force on the scale of the U.S.

forces, most countries do not maintain an extensive allocation for military uses, and such

allocations that exist differ between countries. Combatant commanders are responsible for

coordinating the use of spectrum with host nations. It is a misconception that DoD can

disregard these coordination requirements during wartime operations. RF emissions are

rarely confined to the territory of the enemy.

4.7.2 International Spectrum Supportability

U.S. acquisition programs need to allow for host nation spectrum supportability from

their earliest stages. Unfortunately, it is not always feasible to identify what nations will host

a given system and impossible to predict, with the ever increasing requirements for wireless

services, what allocations will be available when a system is finally deployed. The DoD has

invested much effort into developing databases of host nation requirements so potential

conflicts can be identified more easily. Identifying the spectrum in which new systems will

operate is a critical part of their development and acquisition.

To help mitigate the uncertainty of worldwide spectrum availability, newer systems are

being designed to operate over larger bands of spectrum than that sanctioned by US&P

allocations. This increases the potential for supportability in other nations. As an example,

the Joint Tactical Radio System (JTRS) is being designed to operate from 2 MHz to 2 GHz.

4-15

This mitigation technique is not applicable to all systems. As described earlier, some

systems can only achieve the desired performance result in a limited portion of the spectrum.

4.8 Summary

DoD uses the full range of frequencies that are available to provide communications,

radar, and radiolocation services. Since the transformation of the armed forces involves

heavier use of communications and sensor systems, DoD requirements will only increase.

Simultaneously, there is greater demand for commercial availability of spectrum. History

has shown that political entities are more responsive to commercial interest, and that taking

spectrum from defense uses and allocating it to new civilian services is perceived as easier

than reallocating civilian uses of spectrum. Economic benefits to governments through

public auctions make it an even more enticing course of action. History has also caused DoD

users to view spectrum sharing as an undesirable solution as it may, de facto, relegate DoD

users to secondary status even when they have the primary allocation of the band. Civilian

users of commercial equipment that operate in frequency bands where the civilian use has

secondary status are usually unaware of this status and believe by buying the equipment that

they have the right to uninterrupted use. Any interference caused by defense spectrum users

is seen as unwarranted. Civilian complaints to political entities and the latter’s responses

result in restrictions being placed on the DoD users. The DoD has already experienced

numerous losses of spectrum and is continuously struggling to retain the capabilities it needs

to perform its mission.

4-16

Section 5

Spectrum Management Organizations and U.S.

Participation in World Radiocommunication Conferences

In this section we describe the current national and international frequency management

organizations. The objective is to identify the key functions of each organization and how

they contribute to the task of spectrum management.

5.1 International Spectrum Management

The ITU is the United Nations’ agency for matters dealing with the telecommunications

field. Within the ITU, the ITU-R carries out activities concerning all matters dealing with

radio communications and spectrum management. WRCs allocate the international RF

spectrum. The Radiocommunication Bureau (BR) registers frequency assignments and

maintains the master international frequency register. The BR also publishes advance

information and coordination information about upcoming systems and assists in resolving

interference. Periodically, the ITU publishes the RR, which is the recognized framework for

the use of the spectrum. These regulations have treaty status. The frequency management

administrations of ITU member nations generally develop national frequency allocation

policies consistent with the RR. The ITU publishes the RR as agreed at the WRCs. States

are still sovereign and may operate systems pursuant to Section 4.4 of the RR, provided they

do not cause and are willing to accept interference.

Figure 5-1 shows the organization of the ITU. Four of the ITU-R organizations affect

frequency management: the WRC, the Radio Regulations Board (RRB), the BR, and the

Radiocommunication Study Groups (SGs).

WRC meetings occur periodically, currently, ever four years.

Each WRC has a specific

agenda associated with specific radiocommunication services. Each WRC updates the RR,

which contain the allocations of the RF spectrum to the various radio services. These

allocations have worldwide effect except where regional or national requirements differ and

regional members agree to these differences. Figure 5-2 illustrates the three recognized

regions of the world. Tropical areas, the region centered on the equator and shaded in Figure

5-2, have additional provisions to offset their higher electrical noise. Exceptions to

allocations for specific countries appear as footnotes in the allocation tables of the RR.

Section 3.4 provides an example of how allocations are specified in the RR.

A shorter period of two years was tried but it was abandoned since it did not provide adequate time for the

issues to be studied appropriately.

5-1

Plenipotentiary Conference

Supreme organ of the union, establishes overall policy and budget; meets every two years

The International Telecommunication Union

World

Conferences on

International

Telecommuni-

cations

ITU Council

Acts on behalf of the

Plenipotentiary Conference

meets once a year

World

Telecommunication

Advisory Council

Secretary General

Deputy Secretary

General

General Secretariat

Coordination

Committee

Radiocommunication

Sector (ITU-R)

Telecommunication

Standardization Sector (ITU-T)

Telecommunication

Development Sector (ITU-D)

Ensures the rational, equitable,

efficient, and economical use of

radio-frequency spectrum by all radio

services, including those using the

geostationary-satellite orbit

Studies technical, operating, and

tariff questions and adopts

recommendations with a view to

global telecommunications

standardization

Facilitates and enhances

telecommunications development

worldwide

World/Regional

Radiocommunication

Conferences

Radiocommunication Assemblies

Radio

Regulations

Board

Study Groups

Director BR

Radiocommunication

Bureau (BR)

Advisory Group

World Telecommunication

Standardization Conferences

Study Groups

Director TSB

Telecommunication

Standardization

Bureau (TSB)

Advisory Group

World / Regional

Develoment Conferences

Study Groups

Director BDT

Telecommunication

Development

Bureau (BDT)

Advisory Group

Figure 5-1. Organization of the ITU

5-2

7 5

6 0

4 0

3 0

2 0

3 0

4 0

6 0

7 5 °

6 0 °

0 °

3 0 °

2 0 °

0 °

2 0 °

3 0 °

4 0 °

6 0 °

1 7 0 °

1 4 0 °1 6 0 ° 1 0 0 °1 2 0 ° 6 0 °

8 0 °

2 0 °4 0 ° 0 ° 2 0 ° 4 0 ° 6 0 °

8 0 °

1 0 0 ° 1 2 0 ° 1 4 0 ° 1 6 0 ° 1 8 0 °

1 7 0 °

1 7 0

1 4 0 °1 6 0 ° 1 0 0 °1 2 0 ° 6 0 °

8 0 °

2 0 °4 0 ° 0 ° 2 0 ° 4 0 ° 6 0 °

8 0 °

1 0 0 ° 1 2 0 ° 1 4 0 ° 1 6 0 ° 1 8 0 °

1 7 0

ABC

R E G I O N 1

R E G I O N 2

R E G I O N 3

Figure 5-2. Spectrum use regions

The RRB approves the Rules of Procedure used by the BR to register frequency

assignments. It addresses matters referred by the BR that cannot be solved by RR or the

rules. It adjudicates interference conflicts among member nations.

The BR operates under the Rules of Procedure established by the RRB to achieve an

orderly recording and registration of frequency assignments, and, when necessary, the

associated orbital characteristics of satellites. It maintains the Master International

Frequency Register. It also advises member nations and the RRB on technical matters of

interference and spectrum use.

The SGs study a variety of questions relating to radiocommunication issues. The focus

of their work is on the use of RF spectrum in terrestrial and space communications, the

characteristics and performance of radio systems, the operation of radio stations, and the

radiocommunication aspects of distress and safety matters. Currently there are 7 study

groups:

SG 1 - Spectrum management

SG 3 - Radiowave propagation

SG 4 - Fixed-satellite service

SG 6 - Broadcasting services (terrestrial and satellite)

5-3

SG 7 - Science services

SG 8 - Mobile, radiodetermination, amateur and related satellite services

SG 9 - Fixed Service

5.2 National Spectrum Management

The Communications Act of 1934 established a duality in spectrum management in the

U.S. between the President for federal government stations and the FCC under the direction

of Congress. By executive order, the President delegated his functions under the act to the

NTIA which is placed under the Secretary of Commerce.

5.2.1 The National Telecommunications and Information Administration (NTIA)

Figure 5-3 illustrates the organization of NTIA. NTIA performs its spectrum

management function through the Office of Spectrum Management (OSM) governed by the

NTIA Manual of Regulations and Procedures for Federal Radio Frequency Management.

Figure 5-4 illustrates the organization of the OSM. Two committees advise the OSM: the

IRAC and the Spectrum Planning and Policy Advisory Committee (SPAC).

Figure 5-3. Organization of the NTIA

5-4

Figure 5-4. Organization of the NTIA Office of Spectrum Management

The mission of the IRAC is to assist the Assistant Secretary in the discharge of his

responsibilities pertaining to the use of the electromagnetic spectrum. The basic function of

the IRAC is to assist in assigning frequencies to U.S. government radio stations and to

develop and execute policies, programs, procedures, and technical criteria pertaining to the

allocation, management, and use of spectrum. The IRAC consist of representatives

appointed by each of the following member departments and agencies:

Agriculture

Air Force

Army

Broadcasting Board of Governors

Coast Guard

Commerce

Department of Energy

Federal Aviation Administration

Federal Emergency Management Agency

General Services Administration

Health and Human Services

5-5

Interior

Justice

National Aeronautics and Space Administration

National Science Foundation

Navy

State

Treasury

U.S. Postal Service

Department of Veterans Affairs

Several DoD agencies provide observers to the IRAC: i.e., The Office of the Assistant

Secretary of Defense, NII, and the Defense Information Systems Agency (DISA).

Additionally, the FCC provides a liaison to the IRAC.

The IRAC consists of six subcommittees. Their missions and roles follow:

Emergency Planning Subcommittee (EPS): Formulates, guides and reviews National

Security Emergency Preparedness (NSEP) planning for spectrum-dependent systems.

Frequency Assignment Subcommittee (FAS): Carries out those functions related to the

assignment and coordination of radio frequencies and the development and execution of

procedures for this purpose. The FAS is divided into two groups: the Aeronautical

Assignment Group (AAG) and the Military Assignment Group (MAG). As their names

imply, the AAG makes recommendations concerning aeronautical use of the spectrum and

the MAG makes recommendations on military uses. Specifically, the AAG reviews all

assignment of frequencies in the bands listed in Table 5-1 and the MAG reviews assignments

in the 225.0-328.6 MHz and 335.4-399.9 MHz bands:

Table 5-1. AAG frequency assignment bands

190-285 kHz 285-435 kHz 510-535 kHz 74.8-75.2 MHz

108-121.9375 MHz 123.5875-128.8125 MHz 132.0125-136 MHz 328.6-335.4 MHz

978-1020 MHz 1030 MHz 1031-1087 MHz 1090 MHz

1104-1146 MHz 1157-1213 MHz 5000-5250 MHz

Space System Subcommittee (SSS): Is responsible for international registration of

government satellite systems within the ITU forum. It gets involved in all NTIA business

concerning space systems.

Spectrum Planning Subcommittee (SPS): Is responsible to the IRAC for all matters

pertaining to planning the use of electromagnetic spectrum.

5-6

Technical Subcommittee (TSC): Is responsible to the IRAC for functions that relate to the

technical aspects of the use of electromagnetic spectrum. The TSC evaluates and makes

recommendations concerning new or existing radiocommunication techniques that affect the

use of electromagnetic spectrum.

Radio Conference Subcommittee (RCS): Undertakes the preparatory work related to

international radio conferences and matters concerning negotiations with international

organizations.

The Spectrum Planning and Policy Advisory Committee (SPAC) consists of 15 non-

Federal members and 4 Federal members, all appointed by the Secretary of Commerce. The

non-federal members are appointed to provide a balanced representation of relevant matters

such as manufacturing, analysis and planning, commercial and other operational spectrum

use, research, academia, and international negotiations. Their role is to review the

recommendations of the IRAC, review the progress of electromagnetic compatibility

programs, provide recommendations on U.S. proposals on spectrum matters with respect to

ITU conferences, and provide strategic planning and recommendations on the efficient use of

spectrum.

5.2.2 The Federal Communications Commision (FCC)

The FCC regulates non-federal government telecommunications and is directly

responsible to Congress. The Rules and Regulations that the FCC follows are codified in

Title 47 of the Code of Federal Regulations. The FCC maintains a liaison with all IRAC

meetings and subcommittees but is not an IRAC member. This liaison assists in spectrum

management actions requiring FCC coordination.

Figure 5-5 illustrates the current organization of the FCC. The roles and responsibilities

of the different bureaus and the Office of Engineering and Technology (OET) follow. Note

that the OET is the arm of the FCC responsible for spectrum management. These

descriptions are taken from the FCC internet site, http://www.fcc.gov/aboutus.html.

The FCC is directed by five Commissioners appointed by the President and confirmed by

the Senate for 5-year terms, except when filling an unexpired term. The President designates

one of the Commissioners to serve as Chairperson. Only three Commissioners may be

members of the same political party. None of them may have a financial interest in any

Commission-related business.

As the chief executive officer of the Commission, the Chairman delegates management

and administrative responsibility to the Managing Director. The Commissioners supervise all

FCC activities, delegating responsibilities to staff units and Bureaus.

5-7

Figure 5-5. FCC organization chart

The Commission staff is organized by function. There are six operating Bureaus and ten

Staff Offices. The Bureaus’ responsibilities include: processing applications for licenses and

other filings; analyzing complaints; conducting investigations; developing and implementing

regulatory programs; and taking part in hearings. The Offices provide support services. Even

though the Bureaus and Offices have their individual functions, they regularly join forces and

share expertise in addressing Commission issues.

Consumer & Governmental Affairs Bureau: Communicates information to the public

regarding Commission policies, programs, and activities. This Bureau is also charged with

overseeing disability mandates.

Enforcement Bureau: Enforces the Communications Act, as well as the Commission’s

rules, orders, and authorizations.

International Bureau - represents the Commission in satellite and international matters.

Media Bureau: Regulates AM, FM radio and television broadcast stations, as well as

Multipoint Distribution (i.e., cable and satellite) and Instructional Television Fixed Services.

5-8

Wireless Telecommunications: Oversees cellular and PCS phones, pagers and two-way

radios. This Bureau also regulates the use of radio spectrum to fulfill the communications

needs of businesses, local and state governments, public safety service providers, aircraft and

ship operators, and individuals.

Wireline Competition Bureau: Responsible for rules and policies concerning telephone

companies that provide interstate, and under certain circumstances intrastate,

telecommunications services to the public through the use of wire-based transmission

facilities (i.e., corded/cordless telephones).

Office of Engineering And Technology: Allocates spectrum for non-government use and

provides expert advice on technical issues before the Commission.

5.3 International Negotiation

Bilateral and multilateral negotiations and agreements concerning telecommunications

and spectrum use are functions of the Department of State (DoS). The DoS leads the

American participation in all international radio spectrum negotiations. The delegations that

participate in these negotiations are ad hoc. Preparations for these meetings involve inputs

from multiple government organizations and private interests.

5.3.1 The Department of State Organization that Handles International

Communications Issues

The DoS Bureau of Economic and Business Affairs (EB) has responsibility for

international negotiations concerning telecommunications issues. This bureau is managed by

the DoS International Communications and Information Policy (CIP) organization. CIP is

organized into three offices: the Office of Bilateral Affairs (CIP/BA), the Office of

Multilateral Affairs (CIP/MA), and the Office of Strategic Planning and Satellite Policy

(CIP/SP), These offices are led by the Coordinator for International Communications and

Information Policy. All three offices could potentially get involved in spectrum issues, e.g.,

the CIP/BA in spectrum issues affecting neighboring countries, or the CIP/MA in its

participation in international conferences, specifically,

The Asia-Pacific Economic Cooperation (APEC),

The Commission for Inter-American Telecommunications (CITEL),

The Organization for Economic Cooperation and Development (OECD),

The ITU, and

The CIP/SP in all matters concerning satellites.

The CIP is supported by two advisory committees, the Advisory Committee for

International Communications and Information Policy (ACICIP) and the International

5-9

Telecommunications Advisory Committee (ITAC). It is the ITAC that develops U.S.

positions for meetings of international treaty organizations.

The ITAC is divided into sectors and study groups that match those of the ITU. There

are three sectors: Telecommunications Standardization (ITAC-T), Telecommunications

Development (ITAC-D), and Radiocommunications (ITAC-R). These in turn are divided

into the following study groups:

ITAC-T includes three study groups:

Study Group A: U.S. policy, standardization, regulation, and competitive aspects of the

operations and tariffs of telecommunications services.

Study Group B: Switching and signaling for transmission systems, integrated services

digital network (ISDN), and software languages.

Study Group D: Data networks and telematic transmission service, digital video, modem,

and digital circuit multiplication techniques

ITAC-D includes two study groups:

Study Group 1 - Telecommunication development, strategies, and policies

Study Group 2 - Development, harmonization, management and maintenance of

telecommunication networks, and services including spectrum management

ITAC-R includes seven study groups:

Study Group 1: Spectrum management

Study Group 3: Radio wave propagation

Study Group 4: Fixed satellite service

Study Group 6: Broadcast Service

Study Group 7: Science services

Study Group 8: Mobile, radiodetermination, amateur, and related satellite services

Study Group 9: Fixed service

In addition to coordinating frequency use through the ITU, the U.S. also coordinates with

nations on its border. For example, there are separate agreements with Canada and Mexico.

5.3.2 Procedures for WRC Participation

At the conclusion of each WRC, a series of domestic and international meetings are held

in preparation for the next WRC. In the first, the Conference Preparatory Meeting (CPM),

delegates review the agenda items that were adopted by the previous WRC and attempt to

5-10

identify areas requiring study before decisions can be made at the next WRC. Also, as part

of this first CPM, as best possible, the outline of the technical report that the second CPM

will forward to the WRC is developed. These products form the basis of each member

country’s preparation for the next conference.

The DoS then takes several actions.

National participation in the WRC begins with participation in the first CPM. At the

conclusion of the CPM, the study areas that are identified for the next WRC are assigned to

the appropriate ITAC-R study group. Activities under ITAC-R prepare for the international

meetings that will build the technical and operating bases (called the CPM report) for the

next WRC. The ITAC-R and its study groups review the CPM outline, create any additional

joint domestic groups needed to do the preparatory work and develop contributions for the

international meetings that develop the CPM inputs. The preparatory process can involve

about a two to four year effort by private sector interests and government agencies. During

the preparatory process, DoS coordinates the activities of the various study groups, clears

U.S. papers through the ITAC-R national committee for submission to dozens of

international meetings, and accredits and leads U.S. delegations as appropriate.

Shortly after DoS activities get underway the NTIA and FCC begin their respective

preparatory activities. NTIA activates its Radio Conference Subcommittee. During the

NTIA activities, all government agencies review their requirements for international

spectrum support taking account of the existing and planned systems the agencies operate.

Agencies negotiate among themselves any conflicting proposals for spectrum. FCC staff

participate as liaison members to the Radio Conference Subcommittee. The end product is

the recommended government proposals that NTIA forwards to the DoS.

The FCC creates an advisory committee of private sector interests that develops non-

government proposals. Any non-government entity can participate in the FCC advisory

committee. The advisory committee members negotiate among themselves to develop a

report of recommended conference proposals to the FCC. Government agencies may

participate, as appropriate, in meetings of the advisory committee. FCC staff use the

advisory committee report to develop non-government proposals.

There is very close coordination between NTIA and FCC as their respective activities

mature into preliminary views and U.S. draft proposals. On controversial issues, domestic

negotiations between FCC, NTIA, and interested government agencies result in identical

proposals being forwarded to the DoS by FCC and NTIA. There is also close coordination

among FCC, NTIA, and the DoS as the ITAC-R activities unfold to ensure that the technical

preparations are consistent with the evolving proposals being developed. As draft proposals

evolve, they are presented at bilateral, regional, and multilateral meetings to build acceptance

and to take account of other countries’ views before developing the final U.S. proposals.

5-11

As the technical and proposal activities mature, the DoS establishes a Principals Group to

decide U.S. positions in cases where technical assessments will not resolve issues or where

national security issues mandate early decisions. As the conference nears, it forms an intra-

governmental core delegation to participate in the next WRC. Note that the President

appoints the head of the U.S. delegation, so an important part of initial business for the

Principals Group is to recommend possible nominees to the White House. The final

delegation reports to the head of the U.S. delegation.

5.4 Impact of the Dual Management Scheme

The dual management scheme used by the U.S. to manage spectrum is different than

most other countries. Most countries have a single government agency to perform the

spectrum management function. Both approaches have advantages and disadvantages.

When a single agency manages spectrum, it is much easier for those countries to arrive at a

national position on how spectrum should be used. However, depending on the country,

either government or private concerns may dominate in the formation of their decisions. The

dual management scheme makes arriving at a single position more challenging, but it ensures

that private and government concerns are both considered. The commercial potential of

spectrum use is ever increasing. The dual management scheme is seen as a benefit in that it

ensures that decisions concerning commercial interests are made only after considering their

impact on government uses of spectrum. Similarly, decisions concerning government

interests are made while taking into account commercial interests. The process generally

results in U.S. proposals that reflect the overall national interest.

The delegations of many countries to international conferences are composed of the

government agencies and private sector companies that use the radio frequency spectrum.

Commercial interests can influence a large number of votes in international negotiation.

Such interests come from large multinational corporations. Whereas nations may only

participate as one voting entity in an international conference, these multinational companies

can provide delegates to several national delegations. Thus, commercial interests can

influence several votes. (This influence is mitigated in national delegations to the extent that

non-commercial interests, for example, security, safety and science interests, are represented

in these delegations.) The rehearsal that the dual management scheme provides in dealing

with these commercial and non-commercial objectives makes the American delegation to

international conferences better able to articulate alternative solutions when government uses

are at risk.

American delegations to international conferences are generally drawn from the

preparatory mechanisms discussed in Section 5.3.2. These individuals include career

government professionals who are experienced in this type of negotiation and private sector

individuals with extensive technical expertise who have participated in the preparatory

process and past conferences. In general, the preparatory process and delegation selection

5-12

represents the checks and balances found among the competing interests that are

representative of our form of government.

5.5 Summary

Radio regulation is managed at the international level by the ITU. Within the United

States, spectrum management is divided among two agencies: the FCC for the private sector

and state and local governments, and NTIA for federal government users. The DoS has

responsibility for all international negotiations concerning international spectrum usage.

Both NTIA and the FCC advise DoS in this role. Each agency has responsibility to seek

assurance that the multi-year preparatory effort for the conference meets U.S. needs and is

supported by the best technical information available. The international negotiation process

occurs in cycles that match the occurrence of each WRC. Each WRC proposes agenda items

for the next WRC. These lead to a list of issues that must be resolved and proposals that

must be generated. The U.S. begins the WRC cycle by operating within a well-defined

advisory committee process that precedes establishment of the U.S. delegation and

appointment of a head of delegation. Meetings are conducted throughout the cycle to

prepare U.S. positions and strategy. Negotiations are held early in bilateral, multilateral, and

regional conferences to garner support for U.S. positions. U.S. delegations to these

conferences are comprised, for the most part, of those who have participated in the multi-

year process that prepared the U.S. proposals and supporting material.

5-13

5-14

Section 6

Spectrum Management within the Department of Defense

In this section we describe the DoD organizations that cooperatively manage the use of

the frequency spectrum. We break the spectrum management mission into two sets of

activities, those associated with planning and those associated with routine operations. We

describe how the organizations interact and identify the procedures that they follow and the

tools that they use to manage spectrum.

The dominant characteristic of current DoD spectrum management is its evolving

procedures that are attempting to be ever more proactive in their approach to identifying and

resolving spectrum management issues.

6.1 DoD Spectrum Management Organizations

The Defense Reform Initiative Directive #31, dated 23 March 1998, defines the current

DoD Spectrum Management Organization. It divides spectrum management into three

elements: a Spectrum Management Directorate that is now part of the Office of the Assistant

Secretary of Defense (OASD) for Networks and Information Integration (NII); a Defense

Spectrum Office (DSO) reporting to the Defense Information Systems Agency (DISA); and,

the Spectrum Management Offices (SMOs) of each Service. The OASD NII Spectrum

Management Directorate is tasked with carrying out the policy, planning, and oversight

functions associated with DoD spectrum matters. The DSO provides the resources to

coordinate joint spectrum matters and assists OASD NII in strategic spectrum planning. The

SMOs manage all spectrum for their respective services and interact to coordinate joint

issues.

An additional DoD organization that plays a major role in spectrum management is the

Joint Spectrum Center (JSC). The JSC is a DISA organization and serves as the DoD focal

point for electromagnetic compatibility (EMC) analysis matters in support of the unified

commands and DoD agencies. It is responsible for developing spectrum management tools.

In this organization the OASD NII has the central role. The Assistant Secretary of

Defense (ASD) for Networks and Information Integration (ASD NII) serves as the Principal

Staff Assistant and Advisor to the Secretary and Deputy Secretary of Defense on DoD

spectrum management matters. The Deputy Assistant Secretary of Defense for Command,

Control and Communications (DASD NII/S3C3) provides policy oversight and guidance for

spectrum management activities within the DoD. The Directorate of Spectrum Management

serves as the principal advisor for DoD spectrum management activities within the DASD

NII/S3C3 in providing day-to-day policy oversight and guidance to the DoD Spectrum

Management Community and also chairs the DoD Spectrum Management Review Group

(SMRG). The SMRG advises DASD NII/S3C3 on policy related spectrum issues.

6-1

The Chairman of the Joint Chiefs of Staff (CJCS) represents the interests of the

Commanders of the Combatant Commands on operational spectrum matters and provides

operational guidance on DoD spectrum matters. The majority of DoD operational spectrum

issues are processed through the Frequency Panel (FP) structure of the Military

Communications-Electronics Board (MCEB). The MCEB is a DoD organization that is

composed of communications and information systems directors from the Joint Staff, the

Services, and selected DoD agencies, together with invited non-voting members from other

DoD components and other government departments. Its mission is to obtain coordination on

military communications-electronics matters among DoD components, between the DoD and

other governmental departments and agencies, and between the DoD and representatives of

foreign nations; to coordinate operational guidance and direction to DoD components; to

furnish advice and assistance to the DoD and its Components on military communications-

electronics matters; and to inform the DoD Chief Information Officer Council of

communications-electronics matters that require high-level attention. The MCEB FP is a

panel of technical experts, drawn from the components that are represented on the MCEB,

that reviews, develops, and coordinates studies, reports, and DoD positions for consideration

by the MCEB in the areas of radio frequency engineering and spectrum management.

Specific issues concerning the use of spectrum are divided among the following permanent

working groups (PWG).

Commercial Satellite Communications Permanent Working Group (COMSATCOM

PWG)

Equipment Spectrum Guidance Permanent Working Group (ESGPWG)

International Permanent Working Group (IPWG)

Joint Communications-Electronics Operation Instructions Permanent Working Group

(JCEOI PWG)

Joint Tactical Information Distribution System and Joint Mulit-Functional Information

Distribution System Permanent Working Group (JTIDS/MIDS PWG)

Land Mobile Radio Permanent Working Group (LMR PWG)

Software Defined Radio Spectrum Management Permanent Working Group (SDRSM

PWG)

Spectrum Management Architecture Permanent Working Group (SMA PWG)

Spectrum Operation Permanent Working Group (SO PWG)

Space System Permanent Working Group (SSPWG)

Figure 6-1 illustrates the organizations that cooperatively manage DoD’s use of

spectrum. The ASD(NII) Spectrum Management Directorate provides policy guidance to the

6-2

organizations that exist to manage spectrum, the service FMOs and the DSO. Day-to-day

operations and routine national and international matters are handled predominantly by these

organizations through their interaction in the permanent working groups of the MCEB

Frequency Panel (FP). In the next two sections, we provide greater detail on how these parts

of the DoD spectrum management organization interact in spectrum management planning

and spectrum management operations.

DASD for

Spectrum,

Space,

Sensors, and

DASD for

Spectrum,

Space,

Sensors, and

NII, Spectrum

Directorate

NII, Spectrum

Directorate

DISA Director

Air Force

FMA

Air Force

FMA

Navy

NMSC

Navy

NMSC

Army

ASMO

Army

ASMO

Defense

Spectrum Office

Defense

Spectrum Office

ASD NII/

DoD CIO

ASD NII/

DoD CIO

Joint Spectrum

Center

Joint Spectrum

Center

Joint Staff,

MCEB

Strategic planning

WRC coordination,

SM issue coordination

Operational

guidance

Combatant

Commands

Policy guidance

Coordination, policy guidance

DSO

Chairs

MCEB FP

Technical Support to

all other organization

HNA

Support

Organizational relationship

Guidance, coordination, support

Participation

Figure 6-1. Organizations that cooperatively manage DoD spectrum

6.2 DoD Spectrum Management Planning Processes

Spectrum management is becoming ever more complex as a result of the increasing

demand for use of RF spectrum by commercial enterprises and governments worldwide.

Meanwhile, the current transformation of the Armed Services hinges on the exploitation of

communications and sensor technologies that rely on the use of RF spectrum thus

simultaneously increasing the quantity of DoD systems that use spectrum. In order to be

successful in this transformation, spectrum must be available globally. The DoD is actively

updating its spectrum policy and spectrum management procedures to address the changing

environment. Most notable in this transition is greater emphasis in planning to anticipate

spectrum needs, to mitigate the risks associated with the acquisition of new systems, and to

6-3

ensure suitable spectrum is available for future operations. We divide this planning into

three categories: strategic planning to ensure spectrum allocations both nationally and

internationally will support projected needs, supportability planning in the acquisition

process to ensure new systems can be supported with spectrum where their use is anticipated,

and operational planning to ensure spectrum is available in theaters of operations to support

deploying spectrum dependent systems.

6.2.1 Strategic Planning

Strategic planning involves projecting future communications requirements and then

developing a roadmap to ensure spectrum allocations, allotments, and regulations will

support those requirements. This activity is made difficult by the numerous demands for RF

spectrum from DoD, other government agencies, foreign governments, and foreign and

domestic commercial interests and the rapidly evolving technologies that use RF spectrum.

To be effective, strategic planners must be aware of DoD’s future needs and the capabilities

of new technologies that DoD intends on developing and other government and civilian

interests are trying to put in service worldwide. They must be engaged in the international

conferences and domestic debates that determine spectrum allocation and allotments. The

success or failure of strategic planning is manifested in how RF spectrum is allocated and

allotted, both internationally and domestically. Thus, strategic planning is executed by

developing an awareness of current and future technologies, identifying their RF spectrum

effects, projecting where the DoD needs access to spectrum and who is likely to encroach on

its availability, developing a plan to protect or to enable DoD capabilities through allocations

and allotments, and finally, participating in the forums that determine spectrum allocations

and allotments so that these plans can be implemented.

Allocation and reallocation activities are instigated to enable new services or additional

users. The reasons to initiate this process can be as many as there are new services, new

users, or new applications that use spectrum. The process from proposal to revisions in

tables of allocations and allotments can take years.

Spectrum allocations and reallocations, especially internationally, are arrived at by

consensus. To achieve consensus requires an understanding of the concerns of interested

parties, a thorough study of the problem, and full consideration of the technical alternatives.

Delegations at any level are most effective when they can effectively present technical

alternatives that will solve everyone’s needs. The iterative process of meeting, presenting

alternatives, and vetting concerns enables delegations to arrive at alternatives that are most

likely to achieve consensus. Thus, iterative meetings of interested parties separated by

periods of study and analysis, characterize the spectrum allocation processes. We see that

effective strategic planning is about solving everyone’s problems not just those of the DoD.

We divide our discussion of the processes of strategic planning into three activities: what

the DoD is currently doing to keep track of changes in technology and to project the future

6-4

issues of spectrum allocation and allotments; how the DoD participates in national forums

that determine spectrum allocations and allotments, and how they participate in international

forums concerning spectrum allocations.

6.2.1.1 Predicting Spectrum Allocations and Allotment Issues

The DoD learned a significant lesson in the recent reallocations of spectrum to

commercial wireless services. Nationally, it is not sufficient to simply identify which

systems will be displaced and the cost of relocating those services if the goal is to protect

DoD capabilities. Rather, it is necessary to articulate the ramifications of spectrum

reallocation in terms of lost capability both in the present and in the future. Similarly, if the

DoD needs allocations and allotments to support future needs it needs to articulate that

requirement in terms of capabilities that will not be available if these changes do not take

place.

In the process of studying spectrum support for new systems, DoD members may identify

potential benefits that can be obtained through a new allocation. The action taken would

depend on the frequency band of the allocation and where in the world the allocation would

be used. Since consensus is the objective, initiation of the process would require a strong

case supported by technical studies. If the proposal will only affect national allocations, then

the organizations that would be involved in the process would be NTIA for federal

government exclusive bands, the FCC if it affects shared bands, and Congress if a

reallocation between the national allocations is required. If the proposal will affect a

neighboring country, then it may be addressed through a bilateral agreement. If the proposal

will affect international allocations, then it would need to be proposed as an agenda item at a

WRC for future consideration. It can take years for changes to be made, with the number of

years being correlated to the number of organizations that would be involved in the changes

and the number of spectrum users that would be affected by the changes.

6.2.1.2 DoD Participation in National Spectrum Allocation Processes

There are three national entry points for introducing allocation proposals: NTIA, FCC, or

Congress. Allocation proposals are introduced within the IRAC of NTIA when a

government user has a new spectrum requirement. The FCC is made aware of these

proposals through their participation as an observer of the IRAC’s activities. The FCC will

introduce an allocation proposal by issuing a Notice of Inquiry (NOI) for fact gathering if

needed, or will issue a Notice of Proposed Rulemaking (NPRM) inviting comments from

interested parties. The FCC allocation process is open to the public and most proceedings

are also provided to the IRAC for comment via the FCC liaison per agreement between the

NTIA and the FCC. Congressional introduction of allocation proposals comes in the form of

legislation. This legislation will either direct the FCC to support a particular service or will

propose the shifting of federal government, non-federal government, and shared allocations

to enable the FCC to support a service. The perception that legislation is necessary results

6-5

from Congressional interaction with constituents and lobbyists. The option to realign

spectrum allocations is motivated by the perception that the FCC will not be able to support

the service with the existing non-federal government spectrum allocation and, recently, the

potential to obtain money through the sale of the realigned spectrum.

Of the three entry points for allocation proposals, the Congressional causes the greatest

concern since it can result in the greatest loss of spectrum and it generally avoids the public

scrutiny of the FCC’s open proceedings. FCC has authority over non-federal government

radio spectrum and can affect the use of shared spectrum. FCC actions can significantly

affect DoD spectrum use for both in-band and adjacent band systems. Government-initiated

proposals will necessarily consider DoD concerns since the DoD is represented in the IRAC

where these proposals are first vetted. Ensuring that DoD concerns are brought to bear in

Congressional actions requires being aware of the reasons for the proposals, identifying

alternatives, and being able to articulate the impact in terms of lost operational capability

resulting from the loss of the spectrum.

6.2.1.3 DoD Participation in International Spectrum Allocation Processes

International allocations are established and changed through the World

Radiocommunication Conferences (WRCs). Each WRC prepares an agenda for the next

WRC and the preliminary agenda for the WRC after next. These agendas contain the

proposals that ultimately lead to spectrum allocations and new spectrum sharing rules. In

preparation for the next WRC, the ITU-R either assigns the proposal to a Working Group

(WG) or creates a Task Group (TG) formed by members of its Study Groups to study the

technical and regulatory issues stemming from the agenda item. The result of these efforts is

a draft report to the next Conference Preparatory Meeting (CPM) to which all members of

the ITU-R consent. Task groups differ from working groups in that they are not permanent

but exist for WRC-related studies only. Participation in the TGs and WGs is open to ITU

member countries and ITU-R sector members.

National participation in these conferences is characterized by the recreation of the study

and task group organization formed in the ITU-R. There is a mirror group formed in the

ITAC-R organization of the DoS. Both the DoD and NTIA have an organization with the

specific purpose of preparing for international conferences—the Radio Conference

Subcommittee (RCS) of NTIA and the International Permanent Working Group (IPWG) of

the MCEB FP. Figure 6-2 illustrates the organizational structure. Issues are studied and

positions are prepared at each level. It is generally expected that for each meeting, a single

position be forwarded to the next level. Thus, the DoD members in the NTIA RCS would

present and support the DoD position formed in the IPWG and approved by the MCEB. The

federal government members of the ITAC-R would present and support the NTIA position

developed by the RCS. Finally, the delegation to international meetings, both regional and

worldwide, will support a position selected by the DoS/EB/CIP (see Section 5.3.2.) Several

meetings are conducted at each level. Each meeting at each level provides the participants

6-6

the opportunity to learn the current leaning of sister organizations or countries. The

exchange of technical information helps improve proposals so that a final consensus can be

obtained. Positions may be modified from meeting to meeting. The iterative international

meetings are also very important to smaller countries that do not have the resources to study

issues, as it gives them the technical information that enables them to take a position.

ITU-R

SG-1

SG-3

SG-9

...

TG-1-9

ITU

ITAC-R

SG-1

SG-3

SG-9

...

TG-1-9

DoS/EB/CIP

WG-1

MCEB

IPWG

NTIA

IRAC

RCS

International

National

DoD

Federal Gov’t

NII

Figure 6-2. Organization to study allocation issues for WRCs

It is feasible for any qualified person to participate in an international meeting.

Individuals in DoD who want to participate submit their requests to NTIA, which forwards

them to CIP. The White House selects the final delegation to the international meeting. As

stated above, members of the delegation are expected to support the national position at the

meeting.

6.2.2 Planning for Spectrum Supportabilty

Due to the international reach of DoD spectrum use, finding the ideal spectrum for use

with a DoD system involves finding sufficient spectrum to support the operational needs of

that system in all the regions of the world where it will be used. The challenge in this task is

that most spectrum is already in use in most regions of the world. Additionally, spectrum

allocations, allotments, and assignments can vary from region to region, country to country,

even within national boundaries. It is the policy of the United States to respect the sovereign

rights of host nation administrations to manage the use of spectrum within their borders and

to not use spectrum without their approval. Finding spectrum that is equally available in all

countries where systems will be used by the DoD may not be feasible. The objective of

planning for spectrum supportability is to mitigate the risk of acquiring systems that cannot

6-7

be used where they are needed. Recent acquisitions are replete with examples where

supportability was not appropriately addressed. Most notable are the following:

The B-2 Bomber’s radar has a high probability of interfering with primary users in

the radar’s frequency band. It is currently being redesigned.

•

The Enhanced Position Location Reporting System (EPLRS) Situational Awareness

Data Link (SADL) cannot be used in Germany or Korea.

The Global Hawk SATCOM data links use exclusive non-government bands, which

means the Global Hawk can only be employed in the U.S. and its Possessions

(US&P) if it can operate in a non-interference mode with primary users of that

spectrum.

COTS Radio Frequency Identification (RF ID) systems were acquired that operated

in frequencies that precluded their use in some European countries.

These costly mistakes have been a primary motivator in current efforts to redefine DoD

policy and procedures with respect to the acquisition of systems that use RF spectrum.

Although certification and spectrum supportability have always been essential parts of

system acquisition, they are now receiving additional emphasis and being more integrated

with new acquisition procedures. Recent revisions in DoD policy on Electromagnetic

Spectrum – Management and Use (DoDD 4650.1) clearly demonstrates the significance with

the additional policy statement:

Spectrum-dependent equipment or systems shall not be developed or procured

without reasonable assurance that required electromagnetic spectrum is, or shall

be, available to support the development, testing, and operation of that equipment

or system.

This same directive puts greater emphasis on the responsibilities of the acquisition

community to ensure compliance with supportability requirements and to provide oversight

to this whole process prior to and through the developmental test and evaluation phase of the

systems. Meanwhile, the spectrum management organizations identified in Section 6.1 are

attempting to better assist the acquisition community through their efforts to anticipate the

needs of the acquisition community, to define how to do spectrum supportability, to train the

acquisition community in these processes, and to provide tools that can assist system

developers in the supportability task (see Section 6.4 for descriptions of these tools).

Supportability planning consists of multiple processes that try to engineer successful

acquisition. First the spectrum management organizations try to anticipate issues with new

technologies and services and to introduce them promptly so that they can address them as

early as possible in the strategic planning process. The remaining processes are either part of

or can be integrated with the acquisition process. In the subsequent subsections we describe

the activities that are undertaken to anticipate issues, we propose how spectrum

6-8

supportability could be integrated with the Defense Acquisition Management Framework and

the Joint Capabilities Integration and Development System (JCIDS), we describe the

components of spectrum supportability analysis, and then we present greater details on the

activities associated with spectrum certification and host-nation coordination.

Although this section focuses on processes that are part of spectrum supportability, it is

important to realize that spectrum supportability is not an end state but an assessment that

risk is sufficiently low that acquisition may proceed. There is no guarantee that a foreign

administration will continue to allow DoD use of the spectrum a system needs.

6.2.2.1 Keeping Track of Technological Innovation

As described in Section 6.2.1.1, the DoD Spectrum Management agencies are actively

engaged in learning the changes that are occurring in uses of spectrum and in the

technologies that are anticipated for DoD systems. The Emerging Technologies Division of

the DSO performs studies and commissions reports toward this end. There is active

engagement between all of the spectrum management organizations and the science and

technology and research and development communities. The goal is to allow those

knowledgeable in spectrum allocations to understand how new systems will use spectrum so

that they can assist the developers in identifying suitable spectrum to support the systems

and identifying those issues that must be addressed through strategic planning.

6.2.2.2 Integration with the Joint Capabilities Integration and Development System

(JCIDS) and the Acquisition Process

DoD’s goal is to integrate spectrum management processes into the JCIDS and

acquisition processes so that spectrum supportable systems are acquired. Figure 6-3

illustrates the acquisition framework and aligns it with the spectrum supportability activities

and the spectrum certification process. This proposal places the spectrum supportability

analysis and other tasks early in the process during the ‘capabilities definition’ phase, a time

when it can best influence system development to produce a spectrum supportable system.

A stated goal of the acquisition community is to exploit commercial off-the-shelf (COTS)

technologies. Although it is more cost effective to buy fully developed systems than to

develop them from scratch, this offers some critical challenges in the area of spectrum

supportability. It does not allow spectrum supportability to be addressed in the development

phase. Although systems can function, they may be designed for use in exclusive-use, non-

government bands, restricting DoD users to a non-interference basis, or they may be

designed to use frequency bands that are not available in the host nation where the

equipment’s use is intended. These potential constraints make it essential that COTS

systems also be certified and evaluated for spectrum supportability prior to acquisition. The

difference between a supportability analysis that precedes system development and a COTS

acquisition is that in the former this analysis can influence the success of an acquisition but

6-9

in the latter it will either prevent a failure or confirm the supportability of the system.

Current policy in DoDD 4650.1 dictates that:

No spectrum-dependent “off-the-shelf” system shall be purchased or procured

without the assurance that spectrum supportability has been, or can be obtained.

IOC

Concept

Refinement

System Development

& Demonstration

Production &

Deployment

Systems Acquisition

Operations &

Support

Sustainment

FRP Decision

Review

FOC

LRIP

Critical Design

Review

Pre-Systems Acquisition

Technology

Development

(Program Initiation)

Band Selection

Spectrum

Supportability

Analysis

Deployed Support

EMC Analysis

Stage I

Conceptual

Stage 2

Experimental

Stage 3

Developmental

Stage 4

Operational

Initial Capabilities

Document (ICD)

Capabilities Development

Document (CDD)

Start Host

Nation Coord

Concept

Refinement

Decision

Req

Definition

Freq

Assignment

Frequency Assignment

Host Nation Approval

Mitigation Measures

Frequency Assignment

ECP upgrades

and P

Stage 4

* Notes to Holders

Sustainment

Disposal

System

Integration

System

Demonstration

Full-Rate Prod &

Deployment

Delete

Freq

Asgnmt

EOA

DT&E

* Documents changes

to the system

Capabilities Production

Document (CPD)

IOT&EIOT&E FOT&EFOT&E

Figure 6-3. Proposed alignment of spectrum supportability activities and spectrum

certification stages with the defense acquisition management framework

6.2.2.3 Spectrum Supportability Analysis

Spectrum supportability analysis assesses the risk factors affecting spectrum

supportability. It includes, as a minimum, assessments of

1. Battlespace performance.

This assessment considers the interaction of the system being acquired with other

systems that would be used in the same battlespace. It identifies whether these systems are

electromagnetically compatible. This assessment also considers whether the spectrum that

the system uses will provide the performance that is desired for that system

2. Planned operating locations.

6-10

This assessment identifies the regions of the world where the system will be used and

ranks the importance of those regions to each other. If different bands of spectrum can

partially support the complete list, the ranking helps identify which bands are most useful.

3. Host nation regulations and processes.

This assessment identifies the current allocations, allotments, and assignments of

spectrum in the proposed bands in the different regions of the world where use is anticipated.

It assesses the expected availability of spectrum support and the difficulty of getting approval

to use the system in those regions.

4. Future plans in worldwide allocations.

This assessment is forward looking at the current trends in spectrum use and attempts to

identify whether these trends may encroach upon the availability of the spectrum intended

for the system to use.

6.2.2.4 Spectrum Certification (DD FM 1494/J/F-12 Process)

Spectrum certification is a mandated process to ensure that: (1) the operational

frequency band(s) and type of services are in conformance with respective national and

international tables of frequency allocations; (2) the equipment conforms to applicable

standards, specifications, regulations, directives, and statutes, and (3) approval is provided to

authorize expenditure of funds for the procurement/development of RF dependent

equipment. DoDI 5000.2 directs that spectrum certification is required for a Mile Stone

(MS) B decision or MS C decision if there was no MS B decision. All spectrum dependent

equipment/systems owned and operated by the DoD require spectrum certification.

Equipment spectrum certification is supported by the MCEB FP Equipment Spectrum

Guidance Permanent Working Group (ESGPWG) and the NTIA Spectrum Planning

Subcommittee (SPS) and Frequency Assignment Subcommittee (FAS). Figure 6-4 illustrates

the spectrum certification process.

6-11

CONTRACTOR

(Generate DD Form 1494)

PROGRAM OFFICE

(Submit DD Form 1494 and

Releasable DD Form 1494 Data)

SPONSORING MILDEP/FMO

(Review and Submit)

NTIA/SPS

(Comments)

JSC

(Comments)

ESG PWG

(Comments)

MCEB

(Distribute releasable

DD Form 1494)

COCOM/HN

(Comment)

CCEB and

MEMBER NATIONS

(Comment)

MCEB ESG PWG

(Prepare guidance and review)

ESG PWG STEERING MEMBER

(Approval guidance)

IRAC

(Comments)

MCEB (JSC)

(Distribute guidance)

SPONSORING MILDEP/FMO

(Appropriate action)

DD Form 1494 Releasable DD Form 1494

CONUS

OCONUS

Figure 6-4. The spectrum certification process

Program managers initiate spectrum certification with the submission of a DD Form

1494, Application for Equipment Frequency Allocation, to the frequency management office

of the pertinent military service: for the Army, The Army Spectrum Management Office

(AMSO); for the Air Force, the Air Force Frequency Management Agency, (AFFMA); and

for the Navy and Marine Corp, the Navy Marine Corp Spectrum Center (NMSC). This

application must be coordinated through the FP of the MCEB before funds are authorized for

the development of any new equipment that will radiate electromagnetic energy. An

application is also required for equipment receiving RF, if protection is desired. An

approved DD Form 1494 establishes that a particular system has a valid spectrum

requirement. The approved DD Form 1494 is later used for frequency assignment. The FAS

of the IRAC must assign a frequency for any transmitting equipment prior to its operation.

Additionally, the applicant must coordinate with the local frequency manager in the proposed

area of deployment.

The DD Form 1494 is submitted at four different stages of an acquisition program and

the process repeats itself for each. The purposes of these submissions follow:

6-12

Stage 1. Planning or Conceptual: Advises on feasibility of getting spectrum support and

recommends modifications or changes in frequency bands needed to get spectrum support.

Stage 2. Experimental: Provides guidance for assuring spectrum support in later stages, and

is needed before obtaining frequency assignments for experimental testing.

Stage 3. Developmental: Provides guidelines for assuring operational spectrum support

needed before obtaining frequency assignments for developmental testing.

Stage 4. Operational: Certifies availability of spectrum support needed before making

operational frequency assignments.

Each Service provides lead times for submission of the DoD Form 1494. As a general

reference, Table 6-1 provides the guidelines specified in Air Force Instruction (AFI) 33-120.

Table 6-1. DD Form 1494 submission lead time guidelines from AFI 33-120

Acquisition Lead Times

Stage Space Systems Other Systems

Planning or

Conceptual

Not earlier than seven years and not later

than two years before satellite launch

Not less than one year before the planned

date of initial operation

Experimental

No later than four years before satellite

launch

Not less than one year before procuring

equipment

Developmental

No later than three years before satellite

launch

Not less than one year before award of a

developmental contract

Operational

No later than two years before satellite

launch

At least six months for all other equipment if

there are only minor changes from previous

stage submissions; one year for significant

changes

The spectrum certification process is not equivalent to spectrum supportability. All it

checks is conformance to regulatory requirements. It does not ensure spectrum availability

nor grant frequency assignments. It does not include host nation coordination nor the

analysis that evaluates the risk of other users encroaching on the spectrum requested.

These lead times are shown as an example. Although they were derived from the latest AFI, recent changes

in the acquisition processes require they be changed.

6-13

6.2.2.5 Host Nation Coordination

The responsibility for host nation coordination falls under Outside CONUS (OCONUS)

geographical area combatant commands. Each combatant command has a small staff

element, their Joint Frequency Management Office (JFMO), to coordinate this host nation

spectrum support. Effective coordination requires both the spectrum management and

acquisition communities to assist these staffs in this effort. Thus the effort to evaluate

supportability increases with as many combatant commands that will use the new system and

the number of countries that the system will be used in.

Ideally, the host nation coordination results in nations assisting the combatant commands

in finding the best spectrum to use and committing to its availability when the system is

finally developed and deployed. However, host nations have their own processes and in

some cases do not do certification or require that assignments be given within 90 days after

certification. There is even a new trend where host nations provide “horizon dates” for

certification that put time restrictions on their commitment to accommodate the new system.

Host nation supportability is an area of great risk in system acquisition.

6.2.3 Operational Planning

Operational planning is the planning that precedes major operations in a theater.

Characteristics of this planning are efforts to:

1. Identify the spectrum that is needed for the operation.

Identifying spectrum need includes making an inventory of spectrum dependent systems

and identifying the bands and quantity of spectrum needed to achieve the capability desired.

This process is complicated since a large part of the planning process involves building a

communications plan that can support communications requirements. Spectrum needs are

identified as the plan is being developed which can proceed up to the start and through

operations.

2. Coordinate the specific availability of spectrum from host nations.

Again, host nation coordination is the responsibility of the combatant commands. Due to

the visibility of these types of operations additional diplomatic support is usually available.

Thus, effective host nation coordination requires synchronization of several parts of DoD and

the government to articulate the same requirements.

3. Divvying the spectrum among users and the systems that use spectrum for optimum

capability.

Upon getting spectrum for operations there is a process of prioritizing who and what

systems get to use the spectrum and where. The process of prioritizing users of spectrum

will naturally result in identifying shortfalls that are operationally critical. These results feed

6-14

into 1 above. Operational planning is a cyclical process that continuously attempts to build

the capability needed by DoD for an operation.

6.3 DoD Spectrum Operations (Assignments)

Frequency assignment rather than allocation is the more common spectrum management

process. Generally, users of spectrum attempt to fit their use into bands that are already

allocated. The challenge is that these bands are already heavily used and any new uses either

require that the new users not affect established users or that the old users give way.

Frequency assignment can be of two types, those that accompany the acquisition of new

systems and those that identify channels that existing systems can use.

Spectrum operations consist of coordinating the assignment of frequencies for use with

existing equipment in support of military operations and training. The presumption is that

the equipment used by the Services can be assigned some portion of the spectrum in the

geographic region in which it will be employed. Obtaining assignments, or a license to

operate, involves coordination among users and with the local frequency management

offices. In the following subsections, we describe the basic procedures users follow to

acquire frequency assignments for their equipment.

6.3.1 Continental United States (CONUS)

Operations in CONUS have two characteristics. First, spectrum allocations, allotments,

and assignments are established and planning involves working within these bounds.

Second, if spectrum needs extend beyond the established assignments, the national spectrum

management organizations—the FCC and NTIA—must get involved.

6.3.1.1 Installations and Ranges in the US&P

Installations and ranges usually have some set of frequencies assigned for use in their

geographic area. Thus, installations and ranges normally have an office that manages the use

of these assigned frequencies. Users that want to operate equipment on these facilities must

coordinate with the installation spectrum management office on the installation. If the

existing frequencies of the installation cannot service the user’s needs, the installation

spectrum management submits the requests to its major command.

6.3.1.2 United States and Possessions (US&P)

When military organizations plan to operate equipment off an installation but within

range of an installation, they must coordinate the use of frequencies with the area frequency

coordinator (AFC). There are eight AFCs, each manned by one of the Services, and each

responsible for a geographic area. The AFCs are responsible to their military department for

administrative purposes and to the MCEB for policy guidance. The AFC’s role is to ensure

spectrum use will not interfere with any installation’s spectrum-dependent system.

6-15

The Federal Aviation Administration (FAA) is responsible for operation of the air traffic

control system. It has been provided several bands of frequencies for this task that are listed

in Table 6-2. Military organizations that want to use frequencies from this list must

coordinate their use with the FAA.

Table 6-2. FAA frequencies and bands

190 - 285 kHz 285 - 435 kHz 510 - 535 kHz

74.8 - 75.2 MHz 108 - 121.9375 MHz 123.5875 – 128.8125 MHz

132.0125-136 MHz 328.6 – 335.4 MHz 978 – 1020 MHz

1030 MHz 1031 – 1087 MHz 1090 MHz

1104 – 1146 MHz 1157 – 1213 MHz 1215 – 1400 MHz

2700 – 2900 MHz 5000 – 5250 MHz 9000 – 9200 MHz

Regular frequency assignments and temporary assignments for greater than 90 days that

operate near the Canadian border are coordinated by the IRAC with the Canadian

Government. Assignments for less than 90 days are coordinated by the service SMO and the

Canadian National Defense Headquarters.

6.3.2 OCONUS Permanent/Fixed

When operating in another country, users of frequencies coordinate through their major

commands to the appropriate Service component in the theater. The service forwards

frequency requests per theater directives. Each country specifies their own procedures for

assigning frequencies. The Combatant Commander is responsible for coordinating

frequency support with these host nations.

6.3.3 Battlespace Spectrum Management (BSM)

Battlespace spectrum management has many of the characteristics of operational

planning; spectrum is identified for use in an operation and then divvied to users in order to

achieve the most capable fighting force. The scope of our description of BSM includes all

processes that manage spectrum use in a theater. BSM has four characteristics: allotment of

spectrum, decentralization of frequency assignment, identification of restricted frequencies,

and methods to resolve interference problems when they occur.

A Joint Task Forces (JTF) is normally created for missions with limited objectives. It

includes a full staff for planning and managing operations. Within the J-6 staff element, the

Command, Control, Communications, and Computer Systems Directorate, is the JTF

Spectrum Management Element (JSME). The JSME’s primary function is to ensure that

assigned JTF military forces are authorized to use sufficient spectrum to execute their

6-16

designated missions. It is the Joint Forces Commander who is responsible for assigning

frequencies; however, this is normally delegated to the JSME. In turn, the JSME may further

delegate this responsibility to subordinate commands. The JSME begins the process by

identifying the spectrum requirements and the spectrum that is available. As described in

Section 6.2.3, this may require extensive coordination with host nations. The JSME then

allots spectrum to the different subordinate commands considering their relative

requirements, the spectrum available, and the geographic distribution and transmission

characteristics of the assets that will use the spectrum (spectrum may be spatially reused).

Given their allotments, subordinate commands assign frequencies to spectrum users. These

assignments are made using the Revised Battlefield Electronic Communications Electronics

Operation Instruction (CEOI) System (RBECS) (see Section 6.4.1.3). These assignments are

made with the same considerations used by the JSME to allot the spectrum. The subordinate

commands then provide the JSME with their CEOIs and an assessment of specific

frequencies that are most critical to their operations. The JSME consolidates the CEOIs into

a Joint CEOI (JCEOI), considers the critical frequency information from the subordinate

commands, the critical frequencies of the host nation and other spectrum users and produces

a Joint Restricted Frequency List (JRFL). The JFRL consolidates and classifies the spectrum

uses that are most critical to operations and to the host nations. The JFRL is provided to the

electronic warfare components so that they can avoid jamming or otherwise interfering with

critical friendly systems.

All frequency assignments and restricted frequency information is consolidated into a

database using the Spectrum XXI tool (see Section 6.4.1.1). This tool helps identify

assignment conflicts. If there are conflicts with assignments, the spectrum managers of the

subordinate commands or Service components will try to resolve the issue among

themselves. Such resolution may involve changing frequency assignments, separating the

users of the conflicting assignments, making a time sharing arrangement, or using some

technical fixes if available. If resolution cannot be achieved by one of these means, meaning

the only solution is for one user to defer to the other, that decision rests in the hands of the

higher commander. Usually, the authority to make the decision is delegated to the

commander’s operations (J3) staff. The J3 makes the decision by prioritizing the capability

or the significance of the missions that the spectrum supports.

Inevitably, some systems that use spectrum may suffer interference. This interference

can come from another friendly source, a host or neighboring nation source, or an enemy

jammer. The DoD has a Joint Spectrum Interference Resolution (JSIR) process that is used

in both tactical and garrison scenarios. The user of the system that suffers interference

initiates the process by describing the effects. The JSIR process first tries to identify the

source and the location of the interfering system with actions depending on who and what the

source is. If the source is a friendly spectrum user, efforts to resolve the interference are the

same as those used to resolve assignment conflicts.

6-17

More detailed discussions of the processes used by DoD for tactical spectrum

management can be found in CJCSM 3320.01A and for interference resolution, in CJCSM

3320.02. ACP 190(B) provides greater detail on spectrum management in combined

operations.

6.4 DoD Spectrum Management Systems and Tools

As described above and throughout this document spectrum management is quite

complex and is more challenging to DoD than other government agencies and national users

due to its global scope . The vast number of administrations that affect spectrum availability

and the great demand and need that DoD has for spectrum requires the compilation of vast

databases of the worldwide use of spectrum. Also unique to the DoD is the availability of

automated tools to assist in the spectrum management task. Below we provide brief

descriptions of the purpose of a number of present and future tools. The vision within the

DoD is to provide an overarching tool that will assist the acquisition community and

operational planners in identifying the availability of spectrum worldwide. We first describe

individual tools and then the objective overarching spectrum architecture.

6.4.1 Spectrum Management and Supportability Tools

Many spectrum management tools already exist to support DoD spectrum management.

Their functions cover a number of spectrum management activities.

6.4.1.1 Spectrum XXI

Spectrum XXI is the joint standard DoD spectrum management system. It is used to

create, modify, renew, and delete permanent/temporary frequency assignments/proposals

worldwide. All DoD spectrum managers coordinate their assignments through Spectrum

XXI , which provides a real time view of all DoD frequency assignments worldwide. It also

includes information on host nation assignments. This database subsequently supports

interference analysis to determine who could be causing interference, and electronic warfare

deconfliction to assess whether jamming activities will interfere with friendly forces or host

nation frequency assignments . Spectrum XXI includes a propagation modeling tool that

enables the assessment of the range of impact of transmissions from an RF emitter.

6.4.1.2 Spectrum Certification System (SCS)

SCS is a database maintained by the JSC that serves as the central archive repository for

all DoD spectrum certification system data. The DD Form 1494 data is entered into this

database after completion of each stage of the certification process.

6-18

6.4.1.3 Revised Battlefield Electronic CEOI System (RBECS)

RBECS is a PC-based tool that gives major commanders near autonomy in the generation

of CEOIs. CEOIs provide guidance on the periodic changing of frequency assignments and

call signs by users. The purpose of these changes is to support communications security by

thwarting enemy efforts to direction find and to jam. An additional purpose of the CEOI is

to provide a directory of users.

6.4.1.4 Army Communications-Electronic System (ACES)

ACES is a modular system that provides Cryptonet Planning, Electronic Protection (EP)

and frequency planning, as well as the Army Signal Operating Instructions and the Joint

Communications Electronic Operating Instructions.

6.4.1.5 Joint Automated Communications Systems (JACS)

JACS is an application that produces a Joint CEOI. JACS has been selected to replace

RBECS.

6.4.1.6 Host Nation Spectrum Worldwide Database (HNSWD)

HNSWD automates the process of host nation support. It contains a database of

historical and current host nation support actions. Warfighters can use this system to identify

spectrum that is likely to be available and then to make a request for it. Acquisition

managers can use it to find bands of spectrum that have been supported by host nations in the

past, so they mitigate the risk of acquiring unsupportable systems.

6.4.1.7 Warfighter Spectrum Usage Planning Tool (WSUPT)

WSUPT supports planning by providing assessments of RF spectrum demands for

different courses of action. It provides “ballpark” estimates of spectrum usage in bandwidth

and then enables users to dynamically assess changes in usage that result from changes in

plans.

6.4.1.8 Defense Spectrum Supportability System (DS3)

DS3 is the next generation spectrum certification system supporting spectrum

management from acquisition through operations. It has a spiral development cycle that will

have up to seven increments that will incorporate global spectrum awareness, regulatory

awareness, spectrum trend analysis and metrics, and support for emerging technologies.

6-19

6.4.1.9 Acquisition Community Connection (ACC) Spectrum Special Interest

Area/Community of Practice Website

The ACC website provides guidance on a number of acquisition topics. DSO maintains a

Spectrum Special Interest Area /Community of Practice website accessible for the ACC. The

spectrum area has documents on a variety of spectrum topics, including spectrum planning,

spectrum supportability, spectrum certification, and E3. It provides an arena for discussion

between the spectrum community and the acquisition community, as well as an information

portal for program managers and operational spectrum units. The website can be accessed

through http://acc.dau.mil/simplify/ev_en.php by selecting the spectrum compliance topic in

the list of special topics or by going directly to

http://acc.dau.mil/simplify/ev.php?URL_ID=11213&URL_DO=DO_TOPIC&URL_SECTION=201.

6.4.2 Overarching Spectrum Architecture

The vision for future spectrum management is to develop a single architecture for all

spectrum management and engineering processes. This vision is the foundation of the

Global Electromagnetic Spectrum Information System (GEMSIS), which is in the initial

stages of capability definition. It will provide a “network-centric” view of these processes.

It will provide support for all operational, acquisition, and regulatory spectrum management

processes, essentially consolidating all the functions of the systems described above in one

place and providing additional features relevant to spectrum management. It is intended that

GEMSIS will be fully integrated into the Global Information Grid (GIG), thus providing the

network-centric environment that will extend the full functionality of the system to the

battlefield user and enable a real time worldwide view of spectrum usage.

6.5 Summary

Procedures for managing the use of spectrum on an operational basis are well developed

and tested routinely. The vast number of actors and interested parties in these processes, the

technical complexity of equipment that uses RF spectrum, and the rapid changes in

technologies that use spectrum make spectrum management very complex. The most

difficult challenges in DoD spectrum management are in the strategic planning for the

acquisition of new systems. Unique in DoD spectrum management is its global scope.

These factors make active and innovative leadership in strategic planning and policy a

necessity. DoD is meeting these challenges. It has taken steps to anticipate the changes that

are occurring in spectrum usage and to modify its spectrum management processes to

proactively address these changes. DoD is a leader in developing methods and tools to

support spectrum management.

6-20

Section 7

Technological Advances and their Impact on Spectrum

Management

Spectrum management has been based on our earliest understanding of how signals are

modulated and sent. As presented in Sections 1 and 3, the method used to manage spectrum

has involved the isolation of users in frequency band, in location, and in time. Advances in

communications technology have provided a myriad of additional dimensions to the problem

and in some cases this paradigm is no longer suitable. To present these advances, we divide

the topic up according to the objectives of the technology. We broadly define the objectives

as information efficiency, spectrum efficiency, digital signal processing, spatial reuse, and

dynamic spectrum management.

The relative improvement that is achieved by these technologies is very dependent on

how one measures the effective use of spectrum. We note that the choice of any particular

metric of spectrum efficiency will tend to favor one solution over another. For example,

measuring the ability of a particular solution to send the most bits of information in the

narrowest band of spectrum may not capture its vulnerability to hostile actions, which would

make it undesirable for military use. Measuring the use of spectrum over time may

underestimate the military’s requirements where short intense use periods that occur during

military actions and training are separated by longer periods of routine operations where use

of spectrum is substantially less. Assigning spectrum based on average use may keep the

military from having enough spectrum to perform its most important missions. Throughout

our discussion of these technological advances we attempt to identify the tradeoffs involved

in using each technology.

Finally, these technological advances can improve the use of spectrum; but using them

would require a reevaluation of the methods used to manage it. These technologies enable

and, in many cases require, flexibility in how spectrum is managed in order for there to be

any advantage. We conclude this section with a discussion of spectrum management models

and describe how these models, and also regulation, promote one solution over another.

7.1 Information Efficient Technologies

When speaking of information efficient technologies we are referring to technologies

used in digital communications that reduce the number of bits required to send information.

These technologies consist of techniques to encode information, to reduce data redundancy,

and to compress data. Included in these technologies are methods to correct errors. Errors

occur in communications and in most cases need to be corrected. Correction methods also

have different levels of efficiency that are a function of the number of bits sent.

7-1

7.1.1 Source Coding

Source coding is the conversion of an analog signal into a stream of bits. There are two

basic methods for converting the analog signal. The first is waveform encoding. In

waveform encoding, the information signal is sampled and each sample is recorded into a

finite number of bits. The second method is model-based source coding. In model based

source coding a mathematical model for a filter is used as the basis of information signal

encoding. The information signal is converted into parameters for the model and a low rate

excitation signal. This is what is transmitted. These modeling techniques can greatly

increase the efficiency of encoding. For example, a voice stream in the public switched

telephone network (PSTN) uses waveform encoding resulting in a 64 kbps stream. The

coding technique used in the current Code Division Multiple Access (CDMA) cellular

telephone standard uses a model-based approach that encodes speech into a variable rate

signal that varies from 1 to 8 kbps. In the worst case this system uses 1/8

the bandwidth

used by PSTN.

Source coding is lossy, meaning some information about the signal is usually lost in the

process of coding. Thus, different source coding techniques may reduce bandwidth but in so

doing sacrifice fidelity. For example, consider encoding techniques for pictures. Pictures

can be arbitrarily reduced to smaller file sizes by making each pixel stored in the file

represent a larger portion of the picture; however, this results in less picture resolution.

Thus, the selection of a source coding technique must consider whether the resulting output

will meet the requirements of the intended use.

7.1.2 Redundancy Reduction

Reducing the redundant transmission of information reduces the quantity of bits sent.

For example, a video encoder may send only a subset of the bits that define a picture frame,

restricting the data sent to the bits defining the portion of the picture that changes between

frames. In a voice system, silent periods that occur naturally in conversations may be

skipped and not transmitted. If done well, such reduction techniques will present no

perceivable difference in information quality.

7.1.3 Data Compression

Data compression reduces redundancy but just with knowledge of the bit stream. That is,

a block of bits is reduced to a smaller set of bits through some algorithm that allows for exact

lossless replication of the original block of bits when an inverse algorithm is applied.

Programs that convert computer files to and from compressed ZIP files are examples of

applications using compression technology. Standard telephone modems use compression to

increase data transfer rates.

7-2

7.1.4 Error Correction

Data transmissions and encoded analog signals have different requirements for errors.

Generally, data transmissions cannot tolerate errors but real time streams such as voice and

video can. Additional bits are added to digital messages to detect errors. These methods can

be made better than 99.9% effective at identifying errors. Errors in data signals can be dealt

with in two ways. The data can be divided into small packets which are repeated if they are

received in error or the data can be encoded with additional bits such that errors can be

corrected at reception. This latter technique is referred to as forward error correction (FEC).

There are several factors that influence the decision on what technique to use, such as how

noisy the environment is and whether acknowledgements are used in the access protocols.

Even in systems with FEC, data packets may still need to be repeated if errors exceed the

capability of FEC to correct them.

Source coded signals are usually real time streams. If delays are tolerable, i.e., the voice

and video streams are not supporting a two way conversation or a teleconference, then signal

buffering together with the retransmit mechanism can be used to handle errors. The buffer at

the output contains space for some signal duration allowing time for retransmissions of

packets with errors without a resulting jitter in the output. In cases where the stream

supports a conversation or control function, such buffering is impractical. For example, the

rule of thumb for telephone conversations is that the maximum end-to-end delay should be

less than 200 msec. With an 8 kbps coding method, building a 48 byte packet will introduce

48 msecs of delay. Additional delays occur in accessing the channel, in transmitting the

packets, and in processing packets across each link of the connection. Buffering would

require accepting further delays. The delay budget is unlikely to allow a reasonably sized

buffer. For this reason, errors in real time streams are either ignored or protected with FEC.

One observation of the source coding techniques is that bits are not created equal. For

example, if waveform encoding is used, the most significant bits are most important. To

understand the significance of bits, just consider an 8 bit number. An error in the most

significant position would be a difference of 128, while an error in the least significant

position would be a difference of 1. The most significant bit is 128 times more significant

than the least significant bit. Model-based encoding also has bits that are more significant.

The bits of the model parameters would have greater significance than bits of the excitation

signal. The choice of whether to use FEC or to allow errors is dependent on how vulnerable

the encoded signal is to errors. The greater the significance of some bits can result in the

overall signal being more vulnerable. It is common practice to protect the more significant

bits with FEC while not protecting the less significant bits. FEC is used closely with source

coding techniques to balance efficiency with the desired quality and reliability of the signal.

7-3

7.2 Spectrum Efficient Technologies

Spectrum efficient technologies seek to send information using the least spectral

bandwidth possible. We identify three types: advanced modulation techniques, pulse

shaping, and better receivers. Although these techniques offer greater efficiency, they tend

to be more vulnerable to noise and interference. They are especially vulnerable in hostile

environments because they are easily detected, intercepted, and jammed. See Section 7.4,

Spatial Reuse Technologies, for the alternatives. It is very important that these differences

be understood as they form the basis of disagreement between civil users and defense users

as to what is the most efficient way to use spectrum.

7.2.1 Advanced Modulation

In Section 1.2 we described modulation and stated that through modulation information

is transferred to a signal. We defined three features of a sine wave that may be changed, the

frequency, the phase, and the amplitude. We stated that each combination of characteristics

used in the modulation techniques is referred to as a symbol and that each symbol can

represent multiple bits depending on the number of symbols used in the modulation scheme.

Advanced modulation schemes attempt to achieve spectrum efficiency by increasing the

number of distinguishable symbols a sine wave can carry. The tradeoff for increasing the

number of symbols is that as the number of symbols increase they become harder to

distinguish, and noise and interference are more likely to cause them to be misinterpreted.

Since symbols represent multiple bits, an error in symbol detection can mean multiple bits

are incorrectly detected.

In digital communications systems, the occurrence of errors in bursts results in the use of

additional techniques to mitigate errors. Interleaving (mixing the bits up before transmission

and then unmixing them at reception) is used to reduce the effect of errors occurring in

bursts. Thus, errors that occur in bursts during transmission are distributed throughout a

packet after reception enabling FEC to be more effective. So FEC, in addition to being used

with source coding, is also used with channel encoding. As the data rates of the modulation

scheme increase so do the probabilities of error. FEC coding and modulation combinations

are used to achieve reliable transmission while keeping spectrum use efficient.

7.2.2 Pulse Shaping

The spectral content of a signal, i.e., the bandwidth it requires, is related to how the

signal changes states. Generally, with digital signals, the more abrupt and drastic the change

in a signal the greater its spectral content. Reducing spectral content involves designing the

signals to gradually change between states. This can be done by shaping the pulse or by

allowing the signal to change its characteristics less drastically. Figure 7-1 illustrates a

shaped pulse and how the spectral content is affected. Digital signals using multiple symbols

can be made to use less bandwidth by allowing time for a gradual change between states.

7-4

-0.2

0.2

0.4

0.6

0.8

1.2

0 1020304050

0 50 100 150 200 250 300 350 400 450

-0.2

0.2

0.4

0.6

0.8

1.2

0 1020304050

0 50 100 150 200 250 300 350 400 450

Figure 7-1. Comparison of the spectral content of pulses that change gradually vs.

rapidly. The pulse in the time domain is shown on the left and their use of spectrum is

shown on the right.

7.2.3 Receiver Capability

Our focus so far has been on transmission technology. Since the effects of interference

happen at receivers, their design also affects the capability of radio communications.

Specifically, receiver design can determine how large a noise floor a signal must overcome

and how much interference transmissions on adjacent bands will cause. The circuitry of

receivers introduces noise. If the receiver is noisy, then received signals must be stronger.

As receivers become less noisy less transmission power is required. The selectivity of a

receiver determines the band of frequencies that it passes to demodulation. As receivers

become more selective, the perceived interference from adjacent bands decreases. Adjacent

channels can be placed closer together. It is this latter improvement that contributes to

spectrum efficiency.

7-5

7.2.4 Tradeoffs

As described in Sections 7.2.1 and 7.2.2, three different signal features—frequency,

phase, and amplitude—are managed to achieve the most efficient waveform possible.

Waveforms with multiple states are designed to increase the rate at which a modulated signal

can transmit data. Meanwhile FEC decreases the rate of information transmission (i.e., more

bits are used to send the information) for the sake of reliability, and waveform shaping

techniques are used to reduce the actual spectrum used by the waveform with the tradeoff of

reducing the rate at which symbols may change. The combination of these three methods is

balanced in the attempt to reliably send the greatest number of bits per spectrum use.

Assuming these techniques are successful, the signal will occupy the narrowest band of

frequencies possible. This means that the transmitted signal has most of its energy within a

narrow band of frequencies. Thus, the signal is easy to detect, intercept, and jam. It also has

less diversity, which makes the signal more susceptible to environmental effects such as fast

fading, as described in Section 1.4.6.

The DoD is currently exploiting these technologies to improve the efficiency of its non-

tactical assets. Spectrum is being refarmed by converting older and wider bandwidth channel

to multiple narrower bandwidth channels. This administrative process is called narrow-

banding. It affects spectrum users in the 138-150.8 MHz , 162-174 MHz, and 406-420 MHz

bands.

7.3 Digital Signal Processing Technology

The classical methods of generating and transmitting signals have used devices and

circuits to isolate signals. The challenge in designing these circuits is that their performance

is frequency dependent. Although this is quite suitable for transceivers that use just one

frequency, transceivers that operate on multiple channels cannot be so well tuned on any one

of them for the sake of operating on all of them. Spectrum management responded to these

limitations by increasing the separation of channels. Additionally, for various reasons, these

transceivers may only operate over a small band of channels. Digital systems operate in a

different manner. Rather than isolating the signal with a circuit, the signal is isolated using

digital signal processing (DSP). In other words, the frequency content and the modulation of

the signal is synthesized through mathematical operations while in a digital form.

Conversions to and from the waveform that is used for transmission occur in digital-to-

analog (DA) and analog-to-digital (AD) conversion circuits respectively. The ability to

isolate and process signals is no longer dependent on the quality and the tuning of circuits,

but rather on the resolution and speed of the AD and the DA conversion and the speed at

which the digital signal processing can be executed. Such systems can also operate over a

wide band of frequencies.

Radios based on this digital technology have ushered in new concepts of how radio

communications can be executed. First, DSP enables the more efficient use of frequency as

7-6

a signal characteristic for defining different symbols of a modulated waveform. Second, the

radio becomes more generic, enabling a single radio to emulate many different types of

systems. We provide greater details in the next two subsections. In later sections we will

describe how these advances enable more dynamic use of spectrum.

7.3.1 Identifying Frequency Content

In classical radios, filter circuits are tuned to allow some band of frequencies to pass and

to attenuate all the others. The passed frequency band is then acted on by the remaining

circuitry, which has been specifically designed to demodulate the expected signal. Although

frequency is used as a modulation characteristic, these circuits are designed to provide a

single output for whatever instantaneous frequency is observed. To classify the full

frequency content of a signal would require taking a very narrow bandpass filter (i.e., a filter

that allows a very narrow band of frequencies to pass) and sweeping it across the frequency

band of the incoming signal and measuring the amplitude of the signal as it sweeps. This is

impractical in a real time system. With DSP, all of this can be executed digitally. The Fast

Fourier Transform (FFT) algorithm can convert a digitized analog signal to its frequency

content. So the views of the signal shown in Figures 1-1b, 1-2b, 1-5, and 1-6 can be

generated. This capability can be exploited in two ways: it enables new methods of

modulation where signals are created by combining frequencies, and it enables the

identification of unused spectrum for possible exploitation. We discuss the first technique

below and will discuss the relevance of identifying unused spectrum in Section 7.5.

The technique of using multiple frequencies to communicate is sometimes referred to as

tone multiplexing. The most common version of this technique is known as Orthogonal

Frequency Division Multiplexing (OFDM). OFDM uses some number of frequencies to

synthesize a waveform. (i.e., the single frequency signals are added to make the transmitted

waveform.) These single frequency signals are separated precisely from each other so that

during the period of detection, they do not interfere with each other. (Their spectrums

overlap each other but the precise timing of the signals over the signal duration prevents

them from interfering with each other.) This is the meaning of the word orthogonal. Each

frequency used in the waveform corresponds to a bit. For example, if the synthesized

waveform has the frequency, then the bit is one. It is 0, otherwise. So a received signal is

checked for frequency content and this correlates directly to a digital word. One popular

standard using OFDM uses 64 different frequencies; thus, each symbol represents a 64-bit

word.

OFDM signals have great diversity. Each of the frequencies will react with the

environment differently. In complex propagation environments where fast fading is likely,

some of the frequencies will suffer interference and others will not. This is actually a

feature. Some portion of the signal will usually get through to the receiver. The application

of FEC coding can make this a relatively reliable modulation technique for hostile

environments.

7-7

7.3.2 Software-Defined Radio

With the observation that all aspects of signal modulation can take place using DSP

comes the additional observation that all radios can be defined in the software that defines

the DSP algorithms that are used. Radios that are designed to exploit this fact are called

software-defined radios (SDR).

Current methods of frequency management have traditionally resulted in the

development of radios to work within a relative small band of frequencies. SDR works on

the concept that the frequency of operation and the modulation technique are not necessarily

defined at the time of manufacture but can be defined later in software. The attraction to

SDR is that it can be designed to work with legacy systems so they can be replaced in an

evolutionary way. Once all legacy systems are replaced with an SDR, then all the SDR

systems can be upgraded to more efficient modulation schemes and/or can be shifted to

operate on a completely different band of frequencies. All of these changes can be achieved

by simply changing the software. The JTRS is an SDR.

7.4 Spatial Reuse Technologies

Spatial reuse technologies attempt to increase the number of users of the same spectrum

either in the same geographic location or in close proximity to each other. These techniques

achieve spatial reuse by either limiting the area across which signals propagate, thus enabling

more users, or by using the diversity that exists between signals because of differences in

how and where they were transmitted, enable the simultaneous use of the same spectrum in

the same vicinity. Reuse techniques based on the control of signal propagation include

directional antennas and networking. Reuse techniques based on exploiting diversity are

spread spectrum, signal polarization, and smart antennas. All of these techniques are very

attractive for military applications since the radiated signals also possess some very desirable

features that reduce their chances of being detected and intercepted by unintended receivers,

as well as their vulnerability to jamming.

7.4.1 Directional Antennas

Directional antennas increase spatial reuse by reducing the coverage over which

transmitters radiate signals and the directions from which a receiver will detect signals.

Receivers outside the coverage of a radiated signal from a transmitter will not receive the

signal and may be able to hear another transmitter using the same frequency. Similarly, a

receiver may be able to distinguish one transmitter from another although being within range

of both. In operation, directional antennas at transmitters are pointed toward the intended

receivers and directional antennas at receivers are pointed toward the transmitter. There is

no requirement for both a transmitter and a receiver to have directional antennas.

7-8

Figure 7.2 illustrates the difference in the operation of transmitters and receivers that use

directional antennas. This illustration plots the location of two pairs of transmitters and

receivers and shows the effect of their antennas. Because T1 and R1 have omni-directional

antennas, they transmit and receive in all directions equally. But since T2 and R2 use

directional antennas they transmit and receive with increased gain in one direction. We note

that although R1 receives in the direction of T2, it will still receive T1’s signal since T2 does

not radiate in the direction of R1. This is so regardless of whether R2 uses a directional

antenna. Similarly, R2 can receive T2’s transmission even though it is in range of T1 since

its antenna gain is so much greater in the direction of T2. This is so regardless of whether T2

uses a directional antenna. It is possible to increase the density of transmitter-receiver pairs

in a geographic area by increasing the number of radios using directional antennas and by

increasing the directionality of the antennas.

Transmitter

Receiver

Relative gain of

the receiving

antenna

Range of

transmission

Figure 7-2. Comparison of omni-directional and directional antenna coverage.

7.4.2 Networking

Networking increases spatial reuse by enabling communicating sources to send a

communication to a distant destination without having to transmit the communication the full

range of their separation. This is accomplished by relaying the communication through

nodes of the network. Since nodes only transmit a short distance, they can use low power in

their transmission and allow other nodes to use the same channel simultaneously. This also

makes it more difficult to detect and intercept those nodes that do communicate.

We note that there is no requirement that networks be formed solely with nodes that use

wireless links. Being able to move traffic across links that do not use the radio spectrum

7-9

(i.e., wired links or optical links) is another method of increasing the availability of RF

spectrum to more services. Placing such links within a network can greatly increase the

capacity of the network and thus the benefit of the RF spectrum. Wireless networks may be

one of two types, centrally controlled or ad hoc.

7.4.2.1 Centrally Controlled Wireless Networks

Centrally controlled wireless networks consist of relatively smart stations called “access

points” or “base stations” that are physically connected to each other and other mobile, and

relatively dumb stations that send and receive all of their traffic through these access points.

The mobile stations communicate with the closest access point. They have no further

understanding of the network topology. The access points work cooperatively to route

communications between sources and destinations. The coverage of these networks is

dependent on the locations of the access points. Examples of this type of network are

cellular telephone systems, the Army’s Mobile Subscriber Equipment (MSE), and the

trunked radio systems that are found on military installations.

Centrally controlled networks have many advantages over ad hoc networks. The smart

access points can easily manage quality of service. Since the mobile stations need only

communicate with access points and are not involved with routing traffic there is much less

overhead; so scaling of the network is not an issue. However, these networks also have

disadvantages. Mobile stations cannot communicate unless they associate with access points

and these access points can become bottlenecks and central points of failure. Centrally-

controlled networks are quite vulnerable to hostile acts in military environments.

7.4.2.2 Ad Hoc Networking

Mobile ad hoc networks (MANET), also referred to as mesh networks, consist of mobile

stations that work cooperatively to form a network. Mobile stations in these networks

discover each other and cooperate to form a network topology. There is no requirement for a

pre-existing infrastructure. The creation of these networks is quite complex and remains a

very active area of research with no clearly defined best approach. Conceptually, they

provide the best networking paradigm for the military and are the objective of several

ongoing programs. There is no single point of failure and no limit to the area over which

they may operate. The current program to develop the Wideband Networking Waveform

(WNW) for the JTRS radio is an effort to build a terminal that will provide this type of

capability for the military. The advantages of MANETs are that they are rapidly deployable

and require no fixed infrastructure. The disadvantages of MANETs are that they don’t

perform uniformly, they are sensitive to use, and they do not scale well with network size.

7-10

7.4.3 Spread Spectrum Communications

Spread spectrum communications, as the name implies, spread the signals of

communication across a wide frequency band. There are three primary methods: frequency

hopping, time hopping, and direct sequence. Of these, frequency hopping is the most

obvious. Radios, rather than transmitting continuously using one carrier on a regular basis,

hop to different frequencies to send portions of the message. Multiple transmitters can then

use the same spectrum by using and hopping to different frequencies. To enable the use of

multiple channels requires the radios in the band to follow hop sequences that are non-

interfering. In this subsection, however, we want to explore more closely the other forms of

spread spectrum. The difference in these methods is that multiple signal will use the exact

same spectrum simultaneously. Below, we describe how a signal is spread in spectrum and

demonstrate that, once spread, it appears as noise. We then describe the differences between

direct sequence (DS) and the time hopping approach of UWB.

7.4.3.1 More Basics of Signals in the Spectrum

In Figure 1-2 we illustrated the spectrum of a square wave. We saw that the spectrum of

the square wave extended continuously from its fundamental frequency, the frequency of the

square wave, f, with each spike occurring at odd multiples of the fundamental frequency, (i.e.

3f, 5f, 7f, …). Certainly, as the frequency of a square wave increases, so too will the breadth

at which its spectrum is spread. A second method of spreading spectrum is to reduce the

width of the signal pulse. In Figure 7-3 we illustrate the correlation of frequency and pulse

width of the modulating signal to how the transmitted signal is spread in spectrum. The

frequency of the pulses determines the specific frequency components used in the spectrum

and the width of the pulses determine the amplitude of those components. Converting

signals to shorter pulses or to a series of fast pulses will spread their spectrum. When these

pulse trains modulate a carrier signal, the spectrum extends in both directions about the

carrier. The more a signal is spread in the spectrum, the lower the perceived signal strength

in the spectrum. If spread sufficiently, the signal can hide behind the background noise.

7-11

-1

τA

τ A

Figure 7-3. Effect of pulse width on spectral content. The shorter pulse width τ

spreads the spectrum further than the τ pulse width.

7.4.3.2 Direct Sequence Spread Spectrum

The concept of direct sequence spread spectrum (DSSS) is illustrated in Figure 7-4. A

low rate data signal (Figure 7-4a) is mixed with what is called a chip sequence, a.k.a. a

pseudo- noise (PN) sequence, (Figure 7-4b). The output of this operation is a new signal

(Figure 7.4c). Since it involves a faster changing signal, its content is spread across the

spectrum. At the receiving end, the arriving signal is mixed with the same PN sequence and

the intelligence is extracted (Figure 7-4d). If there is an interfering signal present in the

received spectrum, that interfering signal will be spread by the PN sequence at the receiver.

As a result, signals can be detected in the presence of other signals (see Figure 7-5).

Additionally, several DSSS signals can be sent and received at the same time as long as their

spreading sequences are different. This is the concept of CDMA. CDMA works best when

the codes used are orthogonal. This means that when the different PN sequences are

multiplied with each other their product is zero. Highly accurate timing of the arrival of

signals at destinations is required for orthogonal CDMA to work.

7-12

Signal

Pseudo-noise

sequence

Transmitted

signal

Recovered

signal

s(t)

pn(t)

a(t) = s(t) ⊕ pn(t)

b(t) = a(t) ⊕ pn(t)

Figure 7-4. Example of Direct Sequence Spread Spectrum (DSSS)

Jamming

signal

Desired

DSSS signal

Desired

signal after

despreading

Jamming signal

is spread

a. Received signals prior to despreading

b. Received signals after despreading

Figure 7-5. Anti-jam characteristics of DSSS

7-13

7.4.3.3 Ultra Wideband

The concept of UWB is to send information in very short pulses that have a very wide

bandwidth because they are short. Receivers detect these pulses, as opposed to seeing noise,

by knowing when to look for them. If several pulses are observed when they are expected to

be present, then the signal is detected to be present. (See Section 1.2.2.)

It is possible to directly transmit very narrow electromagnetic impulses without

modulating them onto a sine wave. These impulses occupy spectrum from zero Hz up to a

frequency that is approximately the reciprocal of the pulse width. This constitutes one form

of UWB technology. A radar that operates on this principle can resolve objects whose

dimensions are similar to the width of the pulse. Such a system transmits energy over a wide

band of spectrum that has been allocated to many other services, and has the potential to

interfere with those services. However, these radars can penetrate obstacles and provide

radio detection capabilities that are not possible in other bands.

There is another form of UWB, where the pulses modulate a sine wave with a bandwidth

that is a substantial fraction of the carrier frequency. If the carrier frequency is appropriately

selected, such a system could operate in a region of the spectrum that is not much used by

other services. However, the services provided by the UWB signal are frequency dependent.

For example, obstacle-penetrating radar would not be possible at higher frequencies.

7.4.4 Signal Polarization

Just as light has polarization so, too, do electromagnetic RF waves. The polarization of

electromagnetic RF waves is determined by antenna geometry. For example a long-wire

vertical antenna will have linear vertical polarization, while a horizontal long wire antenna

will have linear horizontal polarization. Reciprocally, best reception occurs when the

receiving antenna’s geometry matches the polarization of the electromagnetic waves. Thus,

polarization can be used to separate signals using the same frequency bands in the same

location by designing antennas to transmit and receive the signals at distinguishably different

polarization.

7.4.5 Smart Antennas

As illustrated in Figure 1-11, signals are detected at an antenna when their fields cross the

antenna. If there are multiple antennas that are physically separated from each other, each

will receive the signal at a different time. This difference in the arrival of signals at each

element of an array of antennas can be used to isolate multiple signals simultaneously. In

this subsection, we describe the basic physics that enable this technology to work.

7-14

Observation point

+ =

Observation point

+ =

a. Direction of propagation with in-phase arrival of signals

b. Direction of propagation with out-of-phase arrival of signals

Figure 7-6. An example of constructive and destructive interference from two signals

that are transmitted in phase from two adjacent antennas based on direction of

propagation.

7.4.5.1 Constructive and Destructive Interference

When two identical signals are transmitted from multiple antenna elements they will

create a wavefront that will propagate in different directions. At a distant point from these

source antennas, an antenna will receive both signals, but since they propagate different

distances, the relative phase of these signals may differ. If the phases line up, then there is

constructive interference and the signals reinforce each other; see Figure 7-6a. If the phases

do not line-up, then there is destructive interference and no signal may be detected, see

Figure 7-6b.

7-15

7.4.5.2 Beamforming

It is possible to select a direction that signals from an array of antennas can

constructively interfere. This direction is affected by selecting the phases and amplitudes of

signals at each of a number of arrayed antenna elements. The direction at which signals

optimally reinforce each other is called the main beam of an antenna. Similarly, it is possible

to excite the antenna elements in a way that causes signals to destructively interfere in a

desired direction. A direction where the signals of an antenna array completely cancel each

other is called a null. Simple beam steering can be accomplished by shifting the phases of

signals to antenna elements based on their physical separation from each other.

Signals detected by each

antenna element

Signal source

Receiving

antennas

Figure 7-7. Differences in received signals caused by multipath arrival of signals at the

receiving antennas

7.4.5.3 Spatial Signatures

In practice, signals from the same source will arrive at antennas from many different

directions. See Figure 7.7. The additional signals occur because of reflections that may

occur off the earth and man-made structures. If there is some prior knowledge about an

arriving signal, multiple element antennas can be optimized to receive signals from a specific

source; Transmissions are normally preceded by a training sequence, and then the

destination applies an algorithm to calculate factors that multiply each antenna’s received

signal, prior to adding them, that causes the sum of these signals to be most similar to the

known training signal. The specific way that a signal arrives at the different antenna

elements is referred to as its spatial signature. Antennas and propagation characteristics are

usually reciprocal. If a receiving antenna can learn the spatial signature, it can then use it to

optimize its return signal to the source. Since there is a rich spatial diversity in how signals

7-16

can arrive, this diversity can be used by antennas to enable them to detect the transmission of

a single source even though the signals of multiple sources arrive at the antenna. It also

enables these antennas to receive multiple signals simultaneously that only differ in their

spatial signature. These antennas can also be used to transmit different signals to multiple

destinations simultaneously. Antennas that can do this are referred to as smart antennas.

The effectiveness of these antennas depends on the geometry and number of elements the

antennas have.

7.5 Dynamic Spectrum Management

Dynamic spectrum management technologies enable spectrum users to identify available

spectrum and then to use that spectrum when they need it. Radios that can perform this

function are referred to as “smart radios.” We consider two different technologies. In the

first, radios check to see what spectrum is currently being used and, in an opportunistic way,

use spectrum that is available (spectrum mining). In the second, radios are aware of the

frequency bands they may use and then work cooperatively to share that spectrum for its

maximum use (dynamic channel assignment). Due to the cooperative nature of these

solutions they would likely be implemented together with networking technologies.

7.5.1 Spectrum Mining

In spectrum mining, radios look for spectrum that is not being used and then use it. The

DSP technologies that enable identification of frequency content (See Section 7.3.1) are also

the enabling technologies in this approach. A radio can sample a band of frequencies and

measure the energy that is present in that spectrum to find those portions that are not being

used. The more complicated part of implementing this technology is knowing which

frequency bands the radio may use and then coordinating its use with the intended

receiver(s). If the spectrum is available in a secondary status, its use must be coordinated to

ensure that it does not violate the terms of its use. These terms of use would include

regulatory constraints to ensure primary spectrum users retain their precedence. How to

define these terms and ensure compliance is still an open issue, as is the regulatory priority in

blocks of spectrum encumbered by other opportunistic users such as WiFi or other

unlicensed devices. In addition, the regulatory status of radios employing a spectrum mining

technique would need to be defined such that their use could be regulated in some manner (or

assigned to unlicensed spectrum only under Annex K of the NTIA manual or Part 15 of the

FCC’s rules). From a technical perspective, an additional problem is coordinating a

transmitter’s intent to use a particular piece of spectrum with the intended receiver so that the

receiver can tune to the correct channel. Because of the knowledge and coordination

required, this technology is best implemented with a network. Radios that have the ability to

intelligently detect whether a particular segment of radio spectrum is being used and use it as

described above are called cognitive radios.

7-17

7.5.2 Dynamic Channel Assignment

Multiple channels may be available for radios to use to communicate. This plurality of

channels can be exploited in several ways. In the first, channels can be assigned on a first-

come first-serve basis such as used in cellular phone systems. The dynamic assignment of

channels to calls enables the channels to be used most efficiently. This method of channel

assignment is a form of statistical multiplexing. In systems where most communications are

randomly-occurring point-to-point communications, the concern is probability of blocking—

the probability that a terminal will ask to use a channel and none will be available. In

systems that dynamically assign channels in this manner, the quantity of traffic that the

multiple channel system can support with the same probability of blocking increases

dramatically. We illustrate this improvement in Figure 7-8. Each of the plots in this figure

corresponds to a different blocking probability, p

. For the case of p

= 0.01, a system that

shares 20 channels can support 1200 times the load supported by a 1 channel system

operating with this same blocking probability.

0 5 10 15 20

Number of Channels

Erlangs

= 0.01

= 0.02

= 0.05

Figure 7-8. Graph of the Erlang C formula showing the benefit of statistically

multiplexing channels to support randomly arriving traffic

The second method of dynamic channel assignment is reassigning the same channel to

different groups of nodes based on their current disposition. In some ways this was done by

the original cellular phone system, which reused frequencies in cells that were separated

An Erlang is the maximum capacity of a channel. So 1 channel has 1 Erlang of capacity and 20 channels

have 20 Erlangs of capacity. The Erlang C formula, which generates this graph, correlates the effective use

of the channels with a probability of being blocked assuming Poisson arrival and exponential service times

for the traffic.

7-18

from each other. However in the cellular phone system this assignment was not dynamic. A

dynamic assignment is accomplished through the ganging of multiple radios where one radio

is on a network. Each user has multiple radios where one is assigned to operate in a network

and the others are assigned logically to multicast groups and are not assigned channels.

Distributed algorithms, implemented in the network, assign the channels. Groups of radios

that want to form a multicast group can be assigned one of the channels available to the

network for one of their non-network radios to use. The network would know which

channels were being used and would assign a channel to the multicast group that was not

being used by any other transmitters in the same vicinity. Transmission characteristics such

as transmit power may also be specified. Thus the network can control the geographic extent

of the spectrum’s use. The network identifies the locations of the nodes of the multicast

group and reassigns the same channel to another multicast group if it is sufficiently separated

in distance from this group. When the second radio is an SDR, it may also be possible to

choose the waveform that is most suitable for the multicast group. This method of dynamic

assignment can greatly reduce the number of channels that are required to support multiple

multicast groups. Through this type of technique, for example, the voice nets of several

different platoons can use the same channel so long as they are separated from each other.

The network can also change the channels of these multicast groups if they maneuver within

range of each other. The assignment and changing of channels can be made totally

transparent to users.

Figure 7-9 illustrates a notional layout of a formation. Each circle represents a member

of the organization. All have a radio on the common ad hoc networking channel. The

numbers adjacent to these circles are the multicast groups that each member subscribes. If a

member has one number it has two radios, one is a member of the common ad hoc network

and the second is available for the multicast group. If a member has two numbers it is a

member of two multicast groups and has three radios total. The dashed lines circumscribe

nodes that belong to the same multicast groups. The number of the multicast group is a

logical association; it does not map directly to a radio channel. Rather, it only indicates that

all nodes that subscribe to the same group should be on the same channel. The network

assigns the channel. Through this approach, multicast groups that are separated from each

other, for example 5 and 9, could be assigned the same channel to use. The spectrum mining

technology would complement this process by verifying the availability of spectrum for

multicast groups to use.

7-19

1, 2

3, 4

2, 4 1, 3

2, 5

2, 6

2,7

3, 8

3, 9

Figure 7-9. A notional layout of members of a military formation showing subscription

to multicast groups

7.6 Alternative Perspectives on Efficient Spectrum Management

There are three models that were proposed by the FCC Spectrum Policy Task Force [23]

in November 2002 for the management of spectrum: the “command-and-control” model, the

“exclusive use” model, and the “commons” model.

The command-and-control model is the traditional process of spectrum management

where the regulatory authority assigns frequencies to spectrum users for specific uses, which

are constrained by rules that limit the characteristics of transmissions. The effectiveness of

the command-and-control model is improved by those technologies that seek spectrum and

information efficiency and by spatial reuse technologies that can be regulated such as the use

of directional antennas.

The exclusive use model gives the licensee the rights to the spectrum within a defined

geographic area and then that licensee manages that spectrum for its optimal use, transferring

the right to use it, if that is appropriate. The mobile phone system is an example of the

exclusive rights model. All of the technologies discussed in this section can be exploited in a

band of frequencies that are available for exclusive use.

The commons model allows significant numbers of unlicensed users to share the

spectrum where usage is governed by technical standards or protocols. There is no right to

protection from interference. The wireless applications authorized for parts of the ISM band,

7-20

where there are no licensed spectrum users, demonstrate this concept. Wireless local area

networks (LANs), Bluetooth devices, cordless phones, and microwave ovens all share the

same frequencies. The spatial reuse technologies that use diversity to allow signals to

coexist in the same space support efficiency in this model. Since transmission power is

limited, networking technologies are exploited to extend the effective range of

communications systems and the type of services they can provide.

The general non-government view is that the exclusive use and commons models will

provide a more efficient management of spectrum, since they decentralize control, making

them more responsive to user needs. In the case of the exclusive use model, licensees can

continuously optimize the assignment of spectrum for best use as defined by the licensee. In

the commons model, users seek to find the best technologies and implementations that

provide the services they need. Although non-government interests often question whether

the government uses spectrum efficiently, the DoD can point to the fact that the exclusive use

model most closely represent how it manages spectrum. As described in Section 6,

frequencies are pooled geographically and provided to users by area coordinators. This

pooling occurs both nationally and internationally. Thus, the DoD, out of necessity, is a

leader in the development and implementation of technologies that are well suited for

dynamic and flexible frequency management

The DoD is at the forefront of developing standards, protocols, and techniques that would

permit flexibility in spectrum use, including the use of the commons model. However, use of

this model for shared government and non-government bands requires further examination

from a technical, regulatory, and political perspective before it should be seriously

considered. Initial use of this model would likely be in dedicated spectrum blocks. More

widespread use may become feasible as technologies and techniques mature and regulatory

issues are addressed. Such improvements may occur as the DoD fields systems that enable

the real time management of spectrum.

7.7 Summary

New communications technologies are providing opportunities to obtain more services

and capacity from spectrum. These technologies improve spectrum use and management in

five general ways:

This statement should not be construed to mean that DoD has established any band as a commons band,

nor, that it currently supports the use of the commons model for the spectrum DoD shares with non-federal

users. Many technical, regulatory, and policy issues remain to make the commons model work in a manner

that will not compromise DoD’s mission capability. The point is that the DoD is a leader in the

development of the technologies that are used in this approach.

7-21

1. Information efficient technologies improve spectrum use by optimizing the quantity of

information that is sent. The goal of information efficient technologies is to reduce the

quantity of bits that must be used to represent information.

2. Spectrum efficient technologies try to reduce the quantity of spectrum needed to send bits

at a specified rate.

3. Digital signal processing technologies change the way signals are processed in

transmitters and receivers. They enable new ways to modulate and detect signals and

make transceivers more flexible. Radio capabilities can be defined in software. DSP has

done for communications transceivers what microprocessors did for the adding machine.

In addition to being able to perform the adding function, computers can do a whole lot

more through software. Similarly, software-defined radios will enable transceivers to do

a whole lot more, many of the capabilities may not as yet have been discovered. At the

very least, they enable transceivers to be continuously upgraded to employ the most

spectrum efficient technologies.

4. Spatial reuse technologies attempt to increase the number of users that may use the same

spectrum simultaneously. It achieves this goal by either reducing the spatial footprint

over which transmissions can be heard, or by using diversity to enable multiple

transmitters to use the same spectrum in the same space at the same time.

5. Dynamic spectrum management enables the management of spectrum in real time.

These systems first identify what spectrum is available and then assign it to users for the

best benefit. These systems may be directed as to what spectrum they might use or may

search for available spectrum and then use it on an opportunistic basis.

None of these technologies is the clear winner in providing the best use of spectrum.

Choosing any particular metric to measure efficient use of spectrum will prefer one

technology over another. Military users of spectrum seek not only the most efficient way to

send bits but also the most reliable way. Metrics that seek spectrum efficiency, i.e.,

bits/seconds/hertz, may favor technologies that are not sufficiently reliable.

Additionally, the model used to manage spectrum may limit or enable the exploitation of

these technologies. There are three management models that have been proposed: command-

and-control, exclusive use, and commons models. The command-and-control model tends to

favor information and spectrum efficient technologies and discourage technologies that

require wider bands of spectrum. The command-and-control model best describes how

management organizations, e.g., ITU, NTIA, and FCC, manage spectrum. While many

believe the exclusive use and commons models provide the most efficient way to manage

Subject to a regulatory regime that would support such use and definition of certain access rights for

opportunistic uses of encumbered spectrum.

7-22

spectrum for its exploitation because they enable the use of all of the technologies described

herein, there are significant regulatory and technical issues associated in implementing these

models, the implications of which have barely begun. It is quite possible the use of these

models may be relegated to dedicated spectrum blocks for the foreseeable future. Although

the DoD is assigned frequencies, they are then pooled and managed by area and by mission.

In effect, the DoD often uses the exclusive use model to manage spectrum use.

Improvements in DoD use of spectrum will follow from the further development of the

technologies we have described and addressing associated regulatory issues.

7-23

7-24

Section 8

Real World Constraints in Spectrum Management

Throughout the century the perception has always been that there is not enough spectrum

available. However, technology continues to resolve this problem by making more spectrum

usable. For example, the upper limit of the spectrum managed by the ITU-R has changed

throughout the years:

Pre 1947 = 200 MHz

1947 = 10.5 GHz

1959 = 40 GHz

1971 = 275 GHz.

300 GHz is at the beginning of the spectrum where electromagnetic radiation starts to

become light; this is the practical limit of radio frequencies. Further increases in radio

spectrum capacity now require us to use the spectrum we have more efficiently. As

described in Section 7, numerous technologies are available to make this possible. However,

the best way to transition is not clear. Ninety years of regulated use and allocations has

created a number of issues that must be considered. The purpose of this section is to

delineate these issues. To do this, we identify four: legacy allocations, legacy equipment, the

desirable features of future spectrum assignments, and transition issues. We follow with a

discussion of how the most recent regulatory actions addressed these challenges—at times

contrary to DoD’s best interests—by providing more spectrum to commercial users.

Specifically, they reallocated federal exclusive use bands for non-federal use.

8.1 Legacy Allocations

The allocation of spectrum has its roots in the order that technology and services were

developed. Generally, the lower the frequency used, the earlier the service was allocated.

There are two issues associated with this sort of development. First, the older technologies

that enabled the services tend to be less efficient. Second, frequencies may not be allocated

in the best way for the services. As described in Section 1, signals operating at different

frequencies perform in different ways. For example, it would be a poor choice to put

emergency and police bands in a frequency band that could not penetrate buildings.

Spectrum management is as much about human nature as it is about science.

Considering the complexity of getting assignments and the role registry plays in a user’s

right to use a frequency, there is great incentive for users that have assignments to hold onto

them even if they are not using them.

8-1

8.2 Legacy Equipment

Improving the use of existing allocations requires the improvement of the equipment.

This most normally requires replacing it. Thus, there is an expense associated with any

changes in how spectrum is allocated. The palatability of any reallocation plan will be

contingent on the number of users of the old allocations. Changing spectrum allocations will

always create an economic loss to someone, and care must be taken to prevent compromising

national security and public safety during the transition.

8.3 Desirable Features of Spectrum Assignments

As one would expect, the new services that are projected for spectrum prefer contiguous

bands of spectrum that are wholly allocated for the exclusive use of the service provider. An

additional consideration is that specific spectrum characteristics that are desired for the

service are frequency dependent.

Anticipated commercial and military uses of spectrum involve supporting multiple users

simultaneously with the same spectrum. The discussions of Section 1 and Section 7

postulate that providing a service that supports multiple users is best accomplished through

assigning contiguous bands of spectrum rather than assigning multiple small slices dispersed

across different bands. Some reasons for this preference are

1. Circuit performance is dependent on frequency.

2. Antenna performance is dependent on frequency.

3. Propagation effects are dependent on frequency.

4. Some advance technologies, such as spread spectrum, require wide bands of

spectrum.

Items 1 to 3 indicate that radios using multiple channels should operate within the same

relative frequencies, or else the transceivers will perform differently for each channel. Thus,

radios are designed and optimized for a specific range of frequencies. Splitting spectrum up

decreases its utility and increases the cost of the devices that are designed to use it.

Referring back to Section 1, we also note that the potential uses of spectrum are

frequency dependent. Any old slice of spectrum will not do; most users want frequency

assignments in the most desirable bands—generally below 3 GHz, in what is commonly

called the “beachfront” portion of the spectrum. The band of frequencies from which an

assignment is given must be selected to provide the propagation characteristics that are

required for the service. For example, a microwave oven can only work in a certain band of

frequencies. Water molecules are especially effective in absorbing energy at about 2.4 GHz

(see Figure 1-22), so most ovens operate near this frequency.

8-2

8.4 Transition Issues

Any decision that directs the reallocation of spectrum or the improvement of the

technologies using it requires a transition. Transitions rarely occur instantaneously. The

natural tendency is for service providers, users, and equipment manufacturers to delay

transitioning until the last moment. This is being played out in the current transition to

digital television. In cases where services are moved from one slice of spectrum to another,

transitions may require providing the same service in two places in the spectrum

simultaneously for the transition period. As equipment is replaced there is the possibility

that incompatible systems will degrade the capability of the service. In cases where

transitions occur in the same band this incompatibility may prevent using the different

equipment simultaneously. These types of problems are especially acute for services that

support public safety and other critical services. Fundamentally important, however, is

maintaining an awareness that technology alone is never the only consideration in spectrum

management. Political issues, regulatory impacts, costs, and legal implications must also be

considered.

8.5 Changing Spectrum Use

Any plan to change the way a particular block of spectrum is used will involve some

level of resistance for the reasons described above. Whether or not technology can overcome

the perceived shortage of spectrum is dependent on some changes in spectrum management.

Policy makers must consider whether projected changes are trying to achieve the best use of

spectrum or simply trying to seize spectrum from those users that will provide the least

resistance or are the easiest to move. If the latter is the motivation, changes are likely to

exacerbate the perceived problem of spectrum shortage. The most recent conversion of

federal exclusive use spectrum to commercial uses has had both an economic and operational

impact on the previous users of that spectrum, most notably, as described in Section 4, on the

DoD.

The historical methods and bureaucracy of spectrum management will tend to favor

spectrum use changes that seek to eliminate inefficient use so that it may be reassigned. This

is not undesirable, but the better solution to any optimization problem requires consideration

of all available resources and desired outcomes in the optimization. Policy makers should be

suspicious of change proposals that focus on eliminating perceived inefficient users rather

than on optimum use of spectrum. Such approaches are opportunistic and are not likely to

achieve the best use of spectrum.

The process of reviewing the use of spectrum and changing the rules to improve the

appropriateness or efficiency of its use is referred to as spectrum refarming. Currently, the

predominant refarming method in the U.S. is “narrow-banding,” where current channels are

being divided into narrower bands.

8-3

8.6 Conclusion

The legacy of over 90 years of spectrum management and the entrenchment of various

users of spectrum create an inertia that works against exploiting technology to improve

spectrum use. Exploiting technology to its fullest will require some changes in the way

spectrum is managed. Unless proper attention is given to optimizing the use of spectrum—

balanced with political, legal, and regulatory consideration—change is unlikely to occur in

the foreseeable future. Political interests will continue to encourage the seizing of federal

allocations. The most recent reallocations of federal exclusive use spectrum have affected

and will continue to affect the ability of the DoD to execute its mission. As pressures

continue to mount for federal users to give-up spectrum, policy makers should be aware that

the modernization of military forces is based on the ability to exploit the communications,

surveillance, and navigation capabilities that are made possible by the use of spectrum. The

evolution of military forces, even with technology improvements, will require more access to

spectrum, not less.

8-4

List of References

1. ITU, Radio Regulations, International Telecommunication Electronic Publishing Service,

2001.

2. DoC NTIA, Manual of Regulations and Procedures for Federal Radio Management,

September 2001.

3. FCC Rules and Regulations (CFR Title 47, Telecommunications, Part 95, Personal Radio

Services)

4. http/:www.itu.int/aboutitu/structure.

5. http/:www.itu.int/aboutitu/overview.

6. http/:www.itu.int/ITU-R.

7. http:/www.state.gov/e/eb/

8. http:/www.state.gov/e/eb/cip/

9. http:/www.state.gov/e/eb/cip/c621.htm

10. http:/www.fcc.gov/fccorgchart.html.

11. http:/www.disa.mil/ops/spectrum.html

12. Defense Spectrum Office Mission and Functions, 2003.

13. Working Group 7 of the Spectrum Planning Subcommittee, Federal Long-Range

Spectrum Plan, NTIA, September 2000.

14. OPNAVINST 2400.20E, Navy Management of the Radio Frequency Spectrum, 19

January 2002.

15. AFMAN 33-120, RadioFrequency (RF) Spectrum Management, 3 April 2002.

16. DoDD 3222.3, Department of Defense Electromagnetic Compatibility Program, 20

August 1990.

17. DoDD 4650.1, “Electromagnetic Spectrum – Management and Use,” XX 2004.

18. DoD Reform Initiative Directive #31 – Realignment of DoD Spectrum Management

Responsibilities.

19. DoDD 5100.35, “Military Communications-Electronics Board (MCEB),” 10 March

1998.

20. Joint Publication 1-02, Department of Defense Dictionary of Military and Associated

Terms, 12 April 2001 as Amended Through 5 September 2003

RE-1

21. DoD Memorandum, “Implementation Guidance on Restructuring Defense Intelligence –

Related Matters” 8 May 2003.

22. CJCSI 3320.01A Electromagnetic Spectrum Use in Joint Military Operations, 30

September 2002.

23. CJCSI 3320.02B, Joint Spectrum Interference Resolution (JSIR) , 12 September 2003.

24. CJCSI 3320.03, Joint Communications Electronics Operation Instructions, 23

September 2003.

25. CJCSM 3320.01A, Joint Operations in the Electromagnetic Battle Space, 27 September

2002.

26. CJCSM 3320.02, Joint Spectrum Interference Resolution (JSIR) Procedures, 8

November 2002.

27. ACP 190(B) Guide to Spectrum Management in Military Operations, May 2003.

28. ACP 190 US Supp-1(C), Guide to Frequency Planning, April 1991.

29. AR 5-12, Army Management of the Electromagnetic Spectrum, 1 October 1997.

30. AFI 33-118, Radio Frequency (RF) Spectrum Management, 3 April 2002.

31. The Communications Act of 1934

32. MCO 2400.2, Marine Corps Management of the Radio Frequency Spectrum, 16 June

1989.

33. Defense Science Board Task Force on DoD Frequency Spectrum Issues, “Coping with

Change: Managing RF Spectrum to Meet DoD Needs,” November 2000.

34. Defense Science Board Task Force on Wideband Radio Frequency Modulation,

“Wideband Radio Frequency Modulation, Dynamic Access to Mobile Information

Networks,” July 2003.

35. FCC “Spectrum Policy Task Force Report” ET Docket No. 02-135, November 2002.

36. Shea, R.M (BG), “Concerning Managing Radio Frequency Spectrum: Military Readiness

and National Security,” Statement before the Subcommittee on National Security,

Veterans Affairs, and International Relations on 23 April 2002.

http:/www.house.gov/reform/ns/statements_witness/shea_april23.html.

37. http:/www.jsc.mil/AcqSup/Gen_spec_policy&info.asp

38.

MCEB PUB 1, Military Communications-Electronics Board Organization, Mission, and

Functions Manual, 1 March 2002.

RE-2

39. MCEB PUB 2, Military Communications-Electronics Board Organization,

Administrative Procedures Manual, 31 May 2002.

40. Howeth, L.S. History of Communications-Electronics in the United States Navy, United

States, Government Printing Office, Washington: 1963. Library of Congress Catalogue

Number: 64-62870.

41. Porter, W.A., “Administrative Aspects of Telecommunications,” IEEE Transactions on

Communications, Vol. 02, Nov 1954, pp. 14 - 17.

42. de Wolf, F.C. “The ITU and Global Communications,” IEEE Transactions on

Communications, Vol. 02, Nov 1954, pp. 18 - 21.

43. Miles, P.D. “International Radio Frequency Management,” IEEE Transactions on

Communications, Vol. 02, Nov 1954, pp. 22 - 25.

44. FCC, “History of Wire and Broadcast Communication,”

http:/www.fcc.gov/cgb/evol.html, May 1993.

45. FCC, “Millimeter Wave Propagation: Spectrum Management Implications,” FCC

Bulletin Number 70, July 1997.

46. IEEE Std 100-192, The New IEEE Standard Dictionary of Electrical and Electronics

Terms, IEEE, 1993.

47. IEEE Std 521

-2002, IEEE Standard Letter Designations for Radar-Frequency Bands,

IEEE, 8 January 2003.

48. http://www.ieeeuse.org/forum/postions/cognitive radio.html, “IEEE USA Position on

Improving Spectrum Usage Through Cognitive Radio Technology.”

49. Kennard, W.E. “Connecting the Globe: A Regulator’s Guide to Building a Global

Information Community,” FCC, June 1999.

50. Maher, R. and Wentland, F., “Spectrum Management Structure and Regulations in the

U.S. – Do we Need to Change in the Twenty First Century,” IEEE Symposium on

Electromagnetic Compatibility, 1990 pp. 380-385.

51. Collin, R.E. Antennas and Radiowave Propagation, McGraw Hill Inc., 1985.

52. Allen, E.W., “The Organization and Functions of the CCIR,” IEEE Transactions on

Communications, Vol. 02, Nov 1954, pp. 26 - 29.

53. MacQuivey, D.R., “Improving Frequency Management to Facilitate Global

Communications,” IEEE Transactions on Communications, Vol. 02, Nov 1954, pp. 30 -

34.

RE-3

54. Smith, E.K. and Kirby, R.C. “The International Radio Consultative Committee (CCIR):

Part 1, IEEE Communications Magazine, Vol. 12, pp. 11 - 18, Jul 1974.

55. Smith, E.K. and Kirby, R.C. “The International Radio Consultative Committee (CCIR):

Part 2, IEEE Communications Magazine, Vol. 12, pp. 12 - 19, Sep 1974.

56. Messere, F. The Federal Communications Commission: An Historical Overview,

http:/www.oswego.edu/~messere, 1996.

57. Merrill, A. B. and Weiskopf, M., “Critical Issues in Spectrum Management for Defense

Space Systems,” http:/www.aero.org/publications/crosslink/winter2002/02.html.

58. I. Brown, A. Kavetsky, M.J. Riccio, and M. Weiskopf, “Spectrum Management and

International Filing: A Program Management Perspective on Process and Recent

Developments,” IEEE Aerospace Conference 2001, Vol. 3, 2001, pp. 3/1261-3/1269.

RE-4

Appendix A

DoD Spectrum Use

Band MHz Military Usage Planned Usage Notes

30-54 Military LMR. This band is used for tactical and

training operations by U.S. military combat net

radio operations that provide command and control

for combat, and combat service support units.

Frequencies also used for air-to-ground

communications for military close air support

requirements as well as some other tactical air-

ground and air-air communications. This band is

broken down into 21 subbands that have different

allocations. Some subbands are not allocated to

Government use. Those subbands are used by the

military services for tactical and training

operations on a non-interference basis.

No changes are planned.

Use expected to

continue.

Multiple

subbands,

some

Government

primary, in

others

military

operates NIB

74.6-74.8 Military LMR. Usage range from administrative

land mobile nets to ground communications for

military aircraft crews

No changes are planned.

Use expected to

continue.

75.2-75.4 Military LMR. Usage ranges from military runway

light control systems to aircrew communications.

No changes are planned.

Use expected to

continue.

76-78 Military LMR. Used primarily for military

services tactical and training operations on a non-

interference basis. No Government allocation.

Use expected to

continue.

Military

operates NIB

108-117.975 Aero-Radionavigation. The military operates

stations in the U.S. and overseas that are available

to all users.

As the U.S. transitions to

satellite-based

radionavigation, these

systems are planned for

partial or full

decommissioning.

This listing is extracted from the Federal Long-Range Spectrum Plan (NTIA, September 2000).

Government primary allocations are mixed into these bands. A full listing of those bands that the

Government has on an exclusive primary basis can be found in Table 3-1.

A-1

Band MHz Military Usage Planned Usage Notes

117.975-

121.9375

Air Traffic Control Communications. Some air

traffic control is provided to military aircraft

equipped with radios that operate in this band.

Use expected to

continue.

123.5875-

128.8125

Air Traffic Control Communications. Some air

traffic control is provided to military aircraft

equipped with radios that operate in this band

Use expected to

continue.

132.0125-

136

Air Traffic Control Communications. Some air

traffic control is provided to military aircraft

equipped with radios that operate in this band

Use expected to

continue.

138-144 Military Communications. This is one of the DOD

primary military and training bands for fixed,

mobile, and aeronautical communications. This is

also used by the Army, Air Force, U.S. Marines,

and the U.S. Coast Guard for non -tactical land

mobile radio that support military functions (i.e.,

fire, crash, security, ambulance, fuels, disaster

preparedness, commanders net, transportation,

etc.) at and in the vicinity of military bases and

numerous military training areas and test ranges.

Also, this band is essential to the Air Force

Auxiliary (Civil Air Patrol) and Auxiliary for

support of and rescue operations. Civil emergency

communications and the Military Affiliate Radio

System (MARS) are also supported in this band.

Use expected to

continue. Use will be

affected by U.S-Mexico

bilateral arrangements in

border area.

148-149.9 Military Communications. This is one of the DOD

primary military tactical and training bands for

fixed, mobile, and aeronautical communications.

This is also used by the Army, Navy, and Air

Force for non-tactical land mobile radio that

maintain military functions (i.e., fire, crash,

security, ambulance, fuels, disaster preparedness,

commanders net, transportation, etc.) at and in the

vicinity of military bases and numerous military

training areas and test ranges.

Use expected to continue

A-2

Band MHz Military Usage Planned Usage Notes

150.05-

150.8

Military LMR. Major users of this band are by the

Army, Navy, and Air Force for non-tactical land

mobile radio that maintain military infrastructure func-

tions (i.e. fire/crash, security, ambulance, fuels, disaster

preparedness, commanders net, transportation, etc.).

Use expected to

continue

162-174 Non Military LMR. The NTIA Manual limits use of

this band by military agencies to non-tactical or on-

base radio operations. The Army Corps of Engineers

uses this band.

Use expected to

continue

Ref 13 shows this

band is used for

non-military

federal operations

216-220 Military Usage. The military uses this band for

communications training, airborne beacon transmitter

locator, test range timing systems, hazardous material

suits (portable-to-portable) communications for air

bases. USA-wide digital telemetry use for nuclear

treaty verification.

Use expected to

continue

220-222 Military LMR. DOD uses frequencies in this band for

tactical and training communications on national and

military test ranges.

Military Radar and Radiolocation operations are

permitted on an NIB basis and are limited to the

military services.

Use expected to

continue

222-225 Military Radar and Radiolocation operations are

permitted on an non-interference basis and are limited

to the military services.

Use expected to

continue

Military operates

NIB.

225-235 Military Communications. Primarily used for A/G and

A/A communications for the control of military

aircraft. Further, the military conducts extensive

fixed, multichannel radio relay training ops in this

band. Major training center instrumentation systems

for data links connecting battle simulation systems on

participants’ platforms (airborne, shipborne, or

surface) to central data processing facilities. The

military services also use this band to perform air and

sea rescues. Rocket testing and other programs'

telemetry systems also operate in this band.

Use expected to

continue

A-3

Band MHz Military Usage Planned Usage Notes

235-322 Military Communications. Primarily used for A/G

and A/A communications for the control of

military aircraft. Further, the military conducts

extensive fixed, multichannel radio relay training

ops in this band. The military services also use this

band to perform air and sea rescues.

MILSATCOM. Tactical and strategic military

satellite communications providing command and

control connectivity between ground, air, and

surface/subsurface mobile platforms, are

conducted in this band.

Use expected to continue

322-328.6 Military Communications. Primarily used for A/G

and A/A communications for the control of

military aircraft. Further, the military conducts

extensive fixed, multichannel radio relay training

ops in this band.

Use expected to continue

335.4-399.9 Military Communications. Primarily used for A/G

and A/A communications for the control of

military aircraft. Further, the military conducts

extensive fixed, multichannel radio relay training

ops in this band. The military services also use this

band to perform air and sea rescues.

MILSATCOM. Tactical and strategic military

satellite communications providing command and

control connectivity between ground, air, and

surface/subsurface mobile platforms, are

conducted in this band.

Use expected to continue

403-406 Military LMR. Military conducts tactical and

training operations in this band on a secondary

basis

Use expected to continue Military

operates on

secondary

basis.

A-4

Band MHz Military Usage Planned Usage Notes

406.1-410 Military LMR. Military conducts tactical and

training operations in this band on a secondary

basis

Undergoing reallotment to

Federal agencies to

provide for restructuring

of channels for use in two

frequency simplex

systems and in

multichannel trunked

system. This will provide

increased spectrum

efficiency.

Military

operates on

secondary

basis.

420-430 Long-Range Radar. This band is used by various

Federal agencies for ground, shipborne, and

airborne long-range surveillance radar systems.

These uses are essential to the nation's aerospace

early warning defense capability, public safety

functions, and the tracking of objects in space.

These radar systems operate with very high power

and wide bandwidths.

Radiolocation. Radiolocation operations are

limited to the military services. This radiolocation

band is also important for and is the only available

radiolocation band for the detection of advanced

technology systems.

Telemetry and Telecommand. NASA and the

military use this band extensively for telemetry

and telecommand.

Flight termination

systems to be moved to

this band from the 406-

420 MHz band.

Use expected to continue.

430-450 Long-Range Radar. This band is used by various

Federal agencies for ground, shipborne, and

airborne long-range surveillance radar. These uses

are essential to the nation's aerospace early

warning defense capability, public safety

functions, and the tracking of objects in space.

These radar systems operate with very high power

and wide bandwidths.

Radiolocation. Radiolocation operations are

limited to the military services. This radiolocation

Use expected to continue

A-5

Band MHz Military Usage Planned Usage Notes

430-450

(cont.)

band is also important for and is the only

radiolocation band for the detection of advanced

technology systems.

Telemetry and Telecommand. NASA and the

military use this band extensively for telemetry

and telecommand

467.5375-

467.7373

Part 95. Military units use Family Radio Service

radios for mobile operations in this band a non-

interference basis.

Use expected to continue Military

operates on

NIB

608-746 Military TV Broadcast Stations 698-746 MHz Band to be

reallocated and auctioned

by 9/30/2002. Otherwise,

use expected to continue.

Military

operates on

NIB.

746-776 Military TV Broadcast Stations at very

remote/isolated sites.

Use expected to continue. Military

operates on

NIB

869-902 Military Radars. Radiolocation operations are

permitted on an non-interference basis and are

limited to the military services.

Use expected to continue. Military

operates on

NIB

902-928 Military Radars. Various Federal agencies operate

mobile and fixed radars in this band. Primary for

military use.

Use expected to continue.

929-932 Military Radars. Radiolocation operations are

permitted on an non-interference basis and are

limited to the military services

Use expected to continue. Military

operates on

NIB

932-935 Point-to-Point. Various Federal agencies use this

band primarily for point-to-point microwave

systems (low density communications links- voice

and/or data) and usually has a paired frequency in

the 941- 944 MHz band.

Military Radars. Radiolocation operations are

permitted on an non-interference basis and are

limited to the military services

Use expected to continue. Military

operates on

NIB

A-6

Band MHz Military Usage Planned Usage Notes

935-941 Military Radars. Radiolocation operations are

permitted on an non-interference basis and are

limited to the military services

Use expected to continue. Military

operates on

NIB

941-944 Point-to-Point. Various Federal agencies use this

band primarily for point-to-point microwave (low

density communications links- voice and/or data)

and usually has a paired frequency in the 932- 935

MHz band.

Military Radars. Radiolocation operations are

permitted on an non-interference basis and are

limited to the military services

Use expected to continue. Military

radars

operate

NIB.

960-1215 Aero-Radionavigation. This band is heavily used for

safety-of-life services within the national and

international airspace systems. Nearly all aspects of

aircraft identification, tracking, control, navigation,

collision avoidance, and landing guidance are carried

out. Major aeronautical radionavigation systems in

this band include the Distance Measuring Equipment

(DME), Air Traffic Control Beacons (ATCRBS),

Mode-S, the military's tactical air navigation system

(TACAN) and Identification Friend or Foe/Selective

Identification Feature (IFF/SIF) systems, and the

Collision Avoidance System (TCAS). These

aeronautical systems are not only essential to civil

and military aircraft, but also to special users such as

the U.S. Space Shuttle Program. Used throughout

the world under International Civil Aviation

Organization agreements.

The Government is allowed to use this band for

communications, navigation, and identification

services on the condition that interference not be

caused to Aeronautical Radionavigation Services.

These systems will be handled on a case-by-case

basis. The military services use the Joint Tactical

Information Distribution System (JTIDS) under this

condition.

Frequency 1176.45 MHz ±

12 MHz is planned for the

new civil GPS signal (L5).

As the U.S. moves to

satellite -based aeronautical,

radionavigation land-based

DME/TACAN will be

reduced to a minimum

operational or

backbonenetwork. Target

phase-down start date is

2008. Sea-based TACAN

will be required in the

foreseeable future. (See

1999 FRP). The FAA has

also targeted this band for

future navigation,

surveillance and data

communications systems

for ATC. A sub-band

centered on 981 MHz is

currently being utilized for

initial trials of the Universal

Access Transceiver (UAT).

Primary to

aero-

radionaviga

-tion,

others uses

are NIB

A-7

Band MHz Military Usage Planned Usage Notes

1215-1240 Surveillance Radars. This band is jointly used by

the FAA and DOD for radiolocation performing

long-range air surveillance and safety-of-flight

enroute air traffic control under Joint Surveillance

System agreements. The military services make

use of the band for high-power long-range

surveillance radars on land and ships in support of

national defense missions. The DOD and FAA

recently deployed a modernized Air-Route

Surveillance Radar Model 4 (ARSR-4) in this

band for air-defense, drug interdiction and air-

traffic control.

Global Positioning System (GPS). The frequency

1227.6 MHz ± 12 MHz is designated for the

Global Positioning System (GPS) as part of the

radionavigation satellite service. This is a 24-hour

satellite constellation system with large numbers

of U.S. and international users.

Use expected to increase.

1240-1300 Surveillance Radars. This band is jointly used by

the FAA and DOD for radiolocation performing

long-range air surveillance and safety-of-flight

enroute air traffic control under Joint Surveillance

System agreements. The military services make

use of the band for high-power long-range

surveillance radars on land and ships in support of

national defense missions. The DOD and FAA

recently deployed a modernized Air-Route

Surveillance Radar Model 4 (ARSR-4) in this

band for air-defense, drug interdiction and air-

traffic control.

Use expected to increase.

1300-1350 Aero-Radionavigation. This band is used heavily

for radiolocation and radionavigation performing

long-range air surveillance and enroute air-traffic

control functions. The DOD and FAA recently

deployed a modernized Air-Route Surveillance

Use expected to increase.

A-8

Radar Model 4 (ARSR-4) in this band for air-

Band MHz Military Usage Planned Usage Notes

1300-1350

(cont.)

defense, drug interdiction and air-traffic control.

Military Aero-Radionavigation. The Air Force

and Navy make use of it for high-power long-

range surveillance radars and air-traffic control

radars, in support of national defense missions.

1350-

1369.05

Military Radars. This band is heavily used for

various military radiolocation applications for

high-power long-range surveillance radars. The

DOD and FAA recently deployed a modernized

Air-Route Surveillance Radar Model 4 (ARSR-4)

in this band for air-defense, drug interdiction and

air-traffic control.

Fixed & Mobile. This band is seeing increased use

for fixed links and mobile links since the Federal

fixed and mobile service allocations were

upgraded to primary in 1989.

Use expected to increase.

1369.05-

1370

Military Radars. This band is heavily used for

various military radiolocation applications for

high-power long-range surveillance radars. The

DOD and FAA recently deployed a modernized

Air-Route Surveillance Radar Model 4 (ARSR-4)

in this band for air-defense, drug interdiction and

air-traffic control.

Fixed & Mobile. This band is seeing increased use

for fixed links and mobile links since the Federal

fixed and mobile service allocations were

upgraded to primary in 1989.

Telecommand Operations. DOD uses this band

for drone telecommand at military test ranges.

Use expected to increase.

1370-1400 Military Radars. This band is heavily used for

various military radiolocation applications for

high-power long-range surveillance radars. The

DOD and FAA recently deployed a modernized

Air-Route Surveillance Radar Model 4 (ARSR-4)

in this band for air-defense, drug interdiction and

NTIA identified 1390-

1400 MHz for

reallocation under OBRA-

93, and reallocated to the

private sector on Jan 1,

1999; however, 17

Any military

use above

1390 MHz

that does not

conform to

noted

A-9

Band MHz Military Usage Planned Usage Notes

1370-1400

(cont.)

air-traffic control.

Fixed & Mobile. This band is seeing increased use

for fixed links and mobile links since the Federal

fixed and mobile service allocations were

upgraded to primary in 1989.

GPS. GPS operates on 1381.05 to relay data on

nuclear bursts detected by orbiting satellites. This

specific requirement is limited to U.S. satellites

Federal sites will continue

to operate for 14 years

(see NTIA Report SP-32).

The band 1385-1390

MHz was returned per the

Defense Authorization

Act of 2000.

exceptions is

NIB

1429-1435 Fixed & Mobile. Though this band was

reallocated for exclusive non-Federal use, essential

Federal operations will continue at 14 sites until

January 2004.

Under the OBRA-93 and

BBA-97, the band 1427-

1435 MHz was identified

for reallocation for

exclusive non-Federal

government use on

January 1999; however,

14 sites were identified to

allow essential Federal

operations to continue

until January 2004

Any military

use after

January 2004

will be NIB.

1435-1525 Aeronautical Telemetry. Vital and extensive use of

the band 1435- 1535 MHz is for aeronautical

telemetry and associate telecommand operations

for flight testing of manned or unmanned aircraft

and missiles, or their major components as well as

for equipment development functions.

Use expected to continue.

1525-1535 INMARSAT. Naval and USCG ships and vessels

use INMARSAT for distress and safety

communications as well as for general

communication services.

Aeronautical Telemetry. Secondary allocation.

Use expected to continue. Military use of

commercial

service.

Aeronautical

telemetry has

secondary

status.

1535-1544 INMARSAT. INMARSAT downlinks to various

Federal agencies' including Naval ships and

vessels for operational use.

Use expected to continue. Military use of

commercial

service

A-10

Band MHz Military Usage Planned Usage Notes

1559-1610 GPS. The Global Positioning System operates on

1575.42 MHz ± 12 MHz (L1link) as part of the

radionavigation-satellite service.

Use expected to continue.

1613.8-

1626.5

Mobile Satellite. Federal government agencies are

users of commercial mobile satellite services

offered in this band supporting terrestrial, ship,

and airborne scientific research experiments and

missions.

Use expected to continue.

1626.5-

1645.5

INMARSAT. Federal government agencies are

users of commercial INMARSAT mobile satellite

services offered in this band in support of natural

disasters and various contingencies

Use expected to continue. Military use

commercial

service

1710-1755 Point-to-Point. Fixed point-to-point medium

capacity microwave systems and tactical radio

relay.

Fixed & Mobile. Mobile use both on ground and

airborne are for air-to-ground video telemetry, air

combat training systems, guided weapons systems

and robotics control.

Under the OBRA-93, the

band 1710- 1755 MHz

was identified for

reallocation to the private

sector for mixed use on

January 1999. Use is

TBD. Also under OBRA-

93, 16 Federal sites

providing essential

operations will be

retained indefinitely in the

band 1710- 1755 MHz.

Under a recent proposal,

military systems would be

cleared from this band at

all but two of those sites.

Reallocation

in process.

Any military

use after

reallocation

will be NIB.

1755-1850 Point-to-Point. Fixed point-to-point medium

capacity microwave systems and tactical radio

relay.

Fixed & Mobile. Mobile use both on ground and

airborne are for air-to-ground video telemetry, air

combat training systems, guided weapons systems

and robotics control. Additionally, some agencies

are using WLANs and tactical point-to-point

Use expected to increase.

A-11

Band MHz Military Usage Planned Usage Notes

1755-1850

(cont.)

communications systems in the 1755-1850 MHz

band.

Space Ops. The Air Force Satellite Control

Network and Satellite Ground Link Subsystem

users have uplink channels for the tracking and

telecommand of various NGSO and GSO satellites

in the 1761-1842 MHz portion of this band.

2200-2290 Aeronautical telemetry except for the flight testing

of manned aircraft.

Space Ops. The Air Force Satellite Control

Network and Satellite Ground Link Subsystem

users have downlink channels for the tracking and

telemetry of various NGSO and GSO satellites in

this band.

Use expected to continue.

2310-2320 Fixed & Mobile. Available, on a secondary basis,

for mobile use both on ground and airborne are for

air-to-ground video telemetry, air combat training

systems, guided weapons systems and robotics

control.

Use expected to continue. Military use

secondary

basis.

2345-2360 Fixed & Mobile. Available, on a secondary basis,

for mobile use both on ground and airborne are for

air-to-ground video telemetry, air combat training

systems, guided weapons systems and robotics

control.

Use expected to continue. Military use

secondary

basis.

2360-2390 Fixed & Mobile. Mobile use both on ground and

airborne are for air-to-ground telemetry and

robotics control.

Telemetry. The 2360-2385 MHz band is used for

defense and commercial aerospace purposes for

telemetry in the flight testing and operation of

aircraft, spacecraft, missiles, and scientific

balloons at military test ranges and NASA centers.

The 2385- 2390 MHz

band was identified for

reallocation to the private

sector on January 1, 2005

under the BBA-97. Use is

expected for Unlicensed

PCS. Use expected to

continue.

The 2385-

2390 MHz

band may be

returned to

original use.

2483.5-2500 Tactical & Training Various tactical and training

operations are conducted in various military test

ranges.

Use expected to continue.

A-12

Band MHz Military Usage Planned Usage Notes

2500-2640 Tactical & Training Various tactical and training

operations are conducted in various military test

ranges on a non-interference basis.

Use expected to continue.

2700-2900 Surveillance Radars. The FAA and military

services operate airport surveillance radars in this

band for the management and control of aircraft in

at around airports and military installations.

Use expected to continue.

2900-3400 Military Radars. This band is used by the military

services' radiolocation systems throughout the U.S.

Use expected to continue.

3400-3500 Military Radars. This is a critical radar band and is

used extensively by all the military services.

Use expected to continue.

3500-3600 Military Radars. This is a critical radar band and is

used extensively by all the military services. In

particular, the U.S. Navy uses this band for

surveillance and precision approach radars to

support its naval air operations.

Use expected to continue.

3600-3650 Military Radars. This is a critical radar band and is

used extensively by all the military services. In

particular, the military services operate fixed and

mobile radionavigational systems in this band as

well as performing sensor and navigational system

calibrations.

Use expected to continue.

3700--4200 Earth Stations. The military services operate earth

stations that receive voice, data, video signals from

an international common carrier GSO satellite

system.

Use expected to continue.

4400-4500 Tactical & Training. This band is heavily used for

military tactical and training communications, both

for line-of-sight, troposcatter and tactical data links.

Use expected to increase.

4500-4635 Tactical & Training. This band is heavily used for

military tactical and training communications, both

for line-of-sight and troposcatter. Additionally, the

DOD operates tactical data links, drone command

and control systems, and numerous other systems.

Use expected to increase.

A-13

Band GHz Military Usage Planned Usage Notes

4.635-4.825 Fixed & Mobile. Numerous Federal fixed

operations use this band for point-to-point

microwave, air combat training systems, tactical

data links, drone command and control systems,

and numerous other systems.

Use expected to increase.

4.825-4.940 Tactical & Training. This band is heavily used for

military tactical and training communications, both

for line-of-sight and troposcatter. Additionally, the

DOD operates tactical data links, drone command

and control systems, and numerous other systems.

Use expected to increase.

5.250-5.350 Military Radars. The military services have

various types of radars (missile detection, imaging,

synthetic aperture radar, frequency agile, ship

sensor, etc.) operating in this band.

Use expected to increase.

Proposed allocation for

radio LANs under WRC

03 Agenda Item 1.5

5.350-5.460 Military Radars. The military services employ

transportable and mobile radars in this band.

Use expected to increase

5.460-5.470 Radars. Some radionavigational surveillance

radars operate in this band along with numerous

radiolocation radars. Secondary allocation for

radiolocation.

Use expected to increase.

5.470-5.600 Radars. This band is used extensively for

transportable and mobile radars as well as for

weather radars. Secondary allocation.

Use expected to increase.

Proposed allocation for

radio LANs under WRC

03 Agenda Item 1.5

5.600-5.650 Radars. This band contains fixed, transportable,

and mobile radars whose purposes are used

primarily for weather radars, surveillance radars,

test range instrumentation radars, and experimental

radar testing. The Navy operates its primary

surface search radar in this band. Secondary

allocation.

Use expected to increase.

Proposed allocation for

radio LANs under WRC

03 Agenda Item 1.5

A-14

Band GHz Military Usage Planned Usage Notes

5.650-5.725 Radars. This band contains fixed, transportable,

and mobile radars whose purposes are used

primarily for weather radars, surveillance radars,

test range instrumentation radars, and experimental

radar testing.

Use expected to increase.

Proposed allocation for

radio LANs under WRC

03 Agenda Item 1.5

5.725-5.830 Military Radars. This band contains fixed,

transportable, and mobile radars whose purposes

are used primarily for surveillance radars, test

range instrumentation radars, airborne

transponders and experimental radar testing.

Extensive use of these radars is in support of

national and military test range operations in the

tracking and control of manned and unmanned

airborne vehicles.

Use expected to increase.

5.830-5.875 Military Radars. This band contains fixed,

transportable, and mobile radars whose purposes

are used primarily for surveillance radars, test

range instrumentation radars, airborne

transponders and experimental radar testing.

Extensive use of these radars is in support of

national and military test range operations in the

tracking and control of manned and unmanned

airborne vehicles. Other radars support missile and

satellite tracking during launch and on-orbit.

Use expected to increase.

5.875-5.725 Military Radars. This band contains fixed,

transportable, and mobile radars whose purposes

are used primarily for surveillance radars, test

range instrumentation radars, airborne

transponders and experimental radar testing.

Extensive use of these radars is in support of

national and military test range operations in the

tracking and control of manned and unmanned

airborne vehicles.

Use expected to increase.

A-15

Band GHz Military Usage Planned Usage Notes

5.925-6.425 Earth Stations. Federal agencies operate earth

stations that transmit voice, data, video signals to

an international common carrier GSO satellite

system. Some of the users are BBG, FAA, and

military services.

Use expected to increase.

7.125-7.235 Point-to-Point. This band is used for fixed point-

to-point microwave links associated with many

Federal agencies' missions including the DOD's

national and military test range communications,

and the remoting of data for such functions as air

traffic control radar, weather, vessel traffic

information, power management, etc.

Use expected to continue.

7.235-7.250 Point-to-Point. This band is used for fixed point-

to-point microwave links associated with many

Federal agencies' missions including the DOD's

and the remoting of data for such functions as air

traffic control radar, weather, vessel traffic

information, power management, etc.

Use expected to continue.

7.250-7.750 Point-to-Point. This band is used for fixed point-

to-point microwave links associated with many

Federal agencies' missions including the DOD's

and the remoting of data for such functions as air

traffic control radar, weather, vessel traffic

information, power management, etc.

Military SATCOM. In this band, the DOD uses

the Defense Satellite Communications Systems

downlinks for global voice and data

communications as well as NATO SATCOM .

Use expected to continue.

7.750-7.900 Point-to-Point. This band is used for fixed point-

to-point microwave links associated with many

Federal agencies' missions including the DOD's

and the remoting of data for such functions as air

traffic control radar, weather, vessel traffic

information, power management, etc.

Use expected to continue.

A-16

Band GHz Military Usage Planned Usage Notes

7.900-8.215 Point-to-Point. This band is used for fixed point-

to-point microwave links associated with many

Federal agencies' missions including the DOD's

and the remoting of data for such functions as air

traffic control radar, weather, vessel traffic

information, power management, etc.

Military SATCOM. In this band, the DOD uses

the Defense Satellite Communications Systems

downlinks for global voice and data

communications as well as NATO SATCOM

Use expected to continue.

8.215-8.400 Point-to-Point. This band is used for fixed point-

to-point microwave links associated with many

Federal agencies' missions including the DOD's

and the remoting of data for such functions as air

traffic control radar, weather, vessel traffic

information, power management, etc.

Military SATCOM. In this band, the DOD uses

the Defense Satellite Communications Systems

downlinks for global voice and data

communications.

Use expected to continue.

8.400-8.500 Point-to-Point. This band is used for fixed point-

to-point microwave links associated with many

Federal agencies' missions including the DOD's

and the remoting of data for such functions as air

traffic control radar, weather, vessel traffic

information, power management, etc.

Use expected to continue.

8.500-8.550 Radars. Mobile and fixed radars operate in this

band for RDT&E support, air and surface target

tracking, and for NASA's planetary radar.

Use expected to continue.

8.550-8.650 Military Radars. Various military target tracking

radars and experimental radars undergoing

RDT&E use this band extensively

Use expected to continue.

A-17

Band GHz Military Usage Planned Usage Notes

8.650-9.000 Military Radars. This band is used by the military

services for mobile and transportable target

acquisition radars, radar RDT&E activities on

national and military test ranges, and tactical and

training exercises.

Use expected to continue.

9.000-9.200 Aero-Radionavigation. This band is used

extensively by the military service for precision

approach radars.

Use expected to increase.

9.200-9.300 Military Radars. This band is used by the military

services for mobile and transportable target

acquisition radars, radar RDT&E activities on

national and military test ranges, and tactical and

training exercises.

Use expected to increase.

9.300-9.500 Military Radars. The military services use this

band for their mobile and transportable radars.

Use expected to increase.

9.500-

10.025

Military Radars. Used extensively for military

tactical and training in the use of its various

radar systems. Some Military RDT&E of radar

systems is done in this band.

Use expected to increase.

10.025-

10.450

Military Radars. Used primarily by the military in

the operation of and in the tactical and training of

various Doppler radars-fixed, mobile, and

transportable. Also used for RDT&E of new radar

systems.

Use expected to continue.

11.700-

12.200

Earth Stations. In this band, some Federal agencies

hold commercial satellite leases for common

carrier service provided by a private sector

domestic satellite system. These Federal agencies

operate Earth stations that transmit voice, data, and

video signals.

Use expected to continue.

13.400-

13.750

Military Radars. The military services operate

shipborne radiolocation point defense weapon

systems that include search radars, tracking radars,

and missile & gunfire control radars.

Use expected to continue.

A-18

Band GHz Military Usage Planned Usage Notes

14.0-14.2 Earth Stations. In this band, some commercial

satellite leases are held by Federal agencies

(uplinks) for common carrier service provided by a

private sector domestic satellite system. These

Federal agencies operate Earth stations that

transmit voice, data, and video signals.

Use expected to increase. Military use

commercial

service.

14.3-14.4 Earth Stations. In this band, some commercial

satellite leases are held by Federal agencies

(uplinks) for common carrier service provided by a

private sector domestic satellite system. These

Federal agencies operate Earth stations that

transmit voice, data, and video signals.

Use expected to increase. Military use

commercial

service.

14.4-14.47 Point-to-Point. This band is used predominately by

fixed, mobile, and transportable telemetry

microwave systems that transmit communications

in addition to other ATC video links, CCTV, range

test data, etc. Mobile uses include airborne

downlink data transmissions. Secondary

allocation.

Use expected to continue. Military

operates on

secondary

basis.

14.47-14.5 Point-to-Point. Fixed and mobile microwave

systems operate extensively in this band for

various purposes that transmit video, audio,and

data. Some uses are at the various national and

military test ranges. Secondary allocation.

Use expected to continue. Military

operates on

secondary

basis.

14.5-

14.7145

Point-to-Point. Fixed and mobile microwave

systems operate extensively in this band for

various purposes that transmit video, audio, and

data. Some uses include the support of various

national and military test range operations,

transmission of air traffic control radar video,

power management.

Fixed and Mobile. The military operates fixed,

mobile, and maritime mobile air-to-air and air-to-

ground data links in this band (common data link).

Secondary allocation to Mobile Service.

Use expected to increase.

A-19

Band GHz Military Usage Planned Usage Notes

14.7145-

15.1365

Point-to-Point. Fixed and mobile microwave

systems operate extensively in this band for

various purposes that transmit video, audio, and

data.

Fixed and Mobile. The military operates fixed,

mobile, and maritime mobile air-to-air and air-to-

ground data links in this band (common data link).

Secondary allocation to Fixed Service.

Use expected to increase.

15.1365-

15.2

Point-to-Point. Fixed and mobile microwave

systems operate extensively in this band for

various purposes that transmit video, audio, and

data. Some uses include the support of various

national and military test range operations,

transmission of air traffic control radar video,

power management.

Fixed and Mobile. The military operates fixed,

mobile, and maritime mobile air-to-air and air-to-

ground data links in this band (common data link).

Secondary allocation to Mobile Service.

Use expected to increase.

15.2-15.35 Point-to-Point. Fixed and mobile microwave

systems operate extensively in this band for

various purposes that transmit video, audio, and

data. Some uses include the support of various

national and military test range operations,

transmission of air traffic control radar video,

power management.

Fixed and Mobile. The military operates fixed,

mobile, and maritime mobile air-to-air and air-to-

ground data links in this band (common data link).

Secondary allocation to Mobile Service.

Use expected to increase.

15.4-15.63 Aero-Radionavigation. This band is used primarily

for mobile or transportable tactical aircraft landing

systems- shore and shipborne.

Use expected to continue.

A-20

Band GHz Military Usage Planned Usage Notes

15.63-15.7 Tactical Aero-Radionavigation. The military

services employ transportable aircraft microwave

landing systems in this band.

Use expected to continue.

15.7-16.6 Airborne Military Radars The military services

employ various airborne radars for functions such

as terrain following, forward looking radars, etc.

Use expected to continue.

16.6-17.1 Airborne Military Radars The military services

employ various airborne radars for such functions

such as terrain following, forward looking radars,

etc.

Experimental. This band supports RDT&E of

experimental radars, test range missile guidance

radars, and target tracking radars.

Use expected to continue.

17.1-17.2 Experimental. Various radar RDT&E activities are

supported in this band.

Use expected to continue.

17.8-20.2 Military SATCOM. Federal government fixed-

satellite and mobile-satellite services is limited in

this band to the military services These services

have a co-primary allocation subject to specified

conditions.

FCC is reallocating

various portions of this

band to different non-

Federal government

services.

Military use

subject to

various

conditions.

20.2-21.2 Military SATCOM. Military EHF satellite

communications systems (GSO) are supported in

this band. Federal government fixed-satellite and

mobile-satellite services is limited in this band to

the military services

Use expected to continue.

21.2-23.6 Point-to-Point. This band is extensively used for

low density microwave radiocommunication links

for voice, data, and video at various government

laboratories, test ranges, and air traffic control

facilities.

Use expected to continue.

A-21

Band GHz Military Usage Planned Usage Notes

25.5-27 Point-to-Point. This band is used for low density

microwave radiocommunications links for voice,

data, and video at government laboratories and

test ranges.

Use expected to continue.

Proposed as a possible

future band for flight test

telemetry by Spectrum

Planning Subcommittee.

30-31 Military SATCOM. In this band, the DOD

operates uplinks to GSO and NGSO satellites for

global voice and data communications. Also, space

telecommand of SATCOMs are done in this band.

Use expected to continue.

31.8-32 Military Radars. Military airborne precision

ground mapping radars operate in this band.

Use expected to continue.

32-32.3 Radionavigation. The Navy operates an automatic

aircraft carrier landing system in this band.

Use expected to continue.

33-33.4 Radionavigation. The Navy operates an automatic

aircraft carrier landing system in this band.

Experimental. DOD RDT&E is conducted in this

band to evaluate millimeter wave systems as well

as the accuracy of sensor and navigational

systems.

Use expected to continue.

33.4-34.4 Experimental. DOD RDT&E is conducted in this

band to evaluate new imaging radar systems as

well as the accuracy of sensor and navigational

systems.

Use expected to continue.

34.5-34.7 Military Radars. Military services in this band are

operating vehicle speed guns and cloud height

measuring radars and are conducting experimental

research in radar techniques.

Use expected to continue.

34.7-35.5 Military Radars. This band is used extensively for

fixed and mobile radars supporting operational and

experimental requirements. Military uses include

employment of airborne side-looking radars, the

experimental research of radars and radar

techniques and improving on the accuracy of

sensor and navigational systems.

Use expected to continue.

A-22

Band GHz Military Usage Planned Usage Notes

36.5-37 Point-to-Point. Fixed microwave systems operate

at military test ranges.

Use expected to continue.

37-38 Point-to-Point. On national and military test

ranges, microwave systems support RDT&E

activities as well as serve as range data links. This

band is used extensively by the military services in

the RDT&E of fixed and mobile theater

deployable communications systems.

Use expected to continue.

38.6-39.5 Point-to-Point. This band is used by the military

services in the RDT&E of fixed and mobile theater

deployable communications systems.

Use expected to continue.

43.5-45.5 Military SATCOM. This band is used extensively

by the DOD for EHF Satellite Communications

System (GSO) uplink

No changes are planned.

Use expected to continue.

NATO Joint Frequency

Agreement identifies 43.5-

45.5 GHz as essential

military MSS requirement

for SATCOM uplinks.

50-55 Experimental. Radar cross section measurements.

59-61 Point-to-Point. Fixed microwave links on various

military test ranges support RDT&E activities.

SATCOM: crosslinks between DoD satellites

61.5-64 Experimental. Experimental testing of millimeter

wave radio systems is performed in this band.

SATCOM: crosslinks between DoD satellites

Use expected to continue.

68.5-71.5 Experimental. RDT&E activities involving radar

cross section measurements is performed in this

band.

93.07-93.27 Experimental. RDT&E of various millimeter wave

radar technologies is done in this band.

93.27-95 Experimental. RDT&E of various millimeter wave

radar technologies and antenna testing is done in

this band.

A-23

Band GHz Military Usage Planned Usage Notes

95-97.88 Experimental. RDT&E activities involving radar

cross section measurements and radar techniques

is performed in this band.

A-24

Appendix B

Department of Defense Electromagnetic Spectrum

Management Plan

Appendix B is comprised of a memorandum from the Deputy Secretary of Defense,

regarding the Strategic Plan for DoD Spectrum Management, followed by the actual DoD

Electromagnetic Spectrum Management Plan.

October 2002

Office of Assistant Secretary of Defense

Command, Control, Communications and Intelligence

Washington, DC 20301

October 2002

Office of Assistant Secretary of Defense

Command, Control, Communications and Intelligence

Washington, DC 20301

October 2002

Office of Assistant Secretary of Defense

Command, Control, Communications and Intelligence

Washington, DC 20301

October 2002

Office of Assistant Secretary of Defense

Command, Control, Communications and Intelligence

Washington, DC 20301

October 2002

Office of Assistant Secretary of Defense

Command, Control, Communications and Intelligence

Washington, DC 20301

October 2002

Office of Assistant Secretary of Defense

Command, Control, Communications and Intelligence

Washington, DC 20301

Foreword

U.S. military forces have enjoyed superiority in many dimensions of armed conflict,

but the tragic events of September 11

exposed threats directly aimed at U.S. territory,

sovereignty, and freedom

Protecting against these threats requires a shift in the basis of

defense planning, as outlined in the Quadrennial Defense Review, from a “threat-based”

model in the past to a “capabilities-based” model in the future.

A “capabilities-based” approach focuses on how an adversary might fight rather than

who the adversary might be and where a war might occur. It establishes the need for the

U.S. to identify the forces and capabilities required to deter and defeat radicals who will

rely on surprise, deception, and unconventional warfare to achieve their objectives.

These asymmetric threats require the DoD to enhance the capability and survivability of

U.S. weapon systems and to leverage information technology and new concepts for more

effective joint operations.

Key technological advances in space and cyber space can help the DoD maintain its

superiority in conflict. Exploitation of space and the denial of the use of space to

adversaries is a key objective for future military competition. Developments in these

arenas are the backbone of highly sophisticated networked and wireless capabilities for

both civilian and military applications. These advances and wireless technologies provide

value to the DoD just as they provide economic viability to the private and commercial

sector. Exploiting wireless capabilities to meet DoD needs creates a major challenge due

to the contention for electromagnetic spectrum access.

DoD understands the criticality of electromagnetic spectrum access, and in order to

face current and future challenges that affect the security of the Nation, developed a new

DoD Electromagnetic Spectrum Management Strategic Plan. This plan maintains and

builds upon DoD’s vision of “assured access” for electromagnetic (EM) spectrum, as

originally articulated in the Joint Spectrum Vision (JSV2010) vision, and to operate in an

increasingly more dynamic and competitive EM spectrum environment in the 21

century.

Table of Contents

Foreword

Table of Contents iii

Section 1 1-1

1.1 Strategic Plan Objective 1-1

1.2 The Department’s Electromagnetic Spectrum Vision 1-2

1.3 Challenges Affecting DoD EM Spectrum Management 1-2

Section 2 2-1

DoD EM Spectrum Management Strategic Goals 2-1

1. Goal: - Improve EM spectrum management and E3 business processes 2-1

2. Goal: - Improve EM spectrum utilization through technological innovation 2-4

3. Goal: - Promote EM spectrum and E3 awareness and education

2-6

4. Goal: - Advocate And defend dod's em Spectrum needs in national and international

em spectrum forums 2-7

Section 3 3-1

Summary 3-1

Section 4 4-1

GLOSSARY 4-1

iii

1-1

Section 1

1.1 Strategic Plan Objective

The objective of this Department of Defense’s (DoD) Strategic Plan is two-fold: First,

to identify goals and associated strategies to “assure the availability of, and access to,

sufficient electromagnetic spectrum” based on the conceptual framework outlined in the

Joint Spectrum Vision 2010 (JSV2010)

; second, to enhance collaboration within the

electromagnetic (EM) spectrum management and the Electromagnetic Environmental

Effects (E3) communities.

This strategic plan establishes goals and objectives along with specific initiatives to

guide the DoD toward achieving its EM spectrum vision and is based on five core

principles:

First, spectrum is a vital national resource. DoD understands that its needs must

be balanced with other national needs and, therefore, supports a US spectrum policy that

balances military and economic security.

Second, spectrum is a core enabler of what DoD does, and is indispensable to

national security. Therefore, DoD should not allow a lack of sufficient spectrum to be a

constraint on the US warfighter or on military capabilities.

Third, DoD recognizes that it must be a good spectrum user. DoD must strive to

be as efficient a spectrum user as it can be.

Fourth, DoD commits to continue investing in new, spectrum-efficient

technologies. It will seek to use technology to alleviate DoD’s and the commercial

sector’s long-term needs for additional spectrum.

Fifth, DoD commits to actively supporting US policies and interests in

international spectrum bodies and international and bilateral negotiations for spectrum

allocation and use. To do this, however, DoD must ensure that the national process

continues to yield positions that reflect the balance required between the public interest

and commercial interests.

Joint Spectrum Vision 2010, September 27, 1999

1-2

These five core principles are integral towards meeting the DoD’s vision of

“assured access” for EM spectrum and maintaining battlefield superiority in the 21

century.

1.2 The Department’s Electromagnetic Spectrum Vision

The DoD’s continued, “assured access” to sufficient EM spectrum is vital to ensure

its ability to achieve the new levels of effectiveness envisioned in Joint Vision 2010 and

reiterated in JV2020. JV2020 addresses the new operational concepts that US joint

forces will need to achieve full spectrum dominance. Joint Spectrum Vision 2010

(JSV2010) provides the conceptual framework to assure access to EM spectrum

necessary for effective joint warfighting and emphasizes the necessity of sufficient

assured EM spectrum access required to meet the objectives of JV2020.

As the US Armed Forces transition to meet new operational concepts, they face an

increased reliance on EM spectrum to accomplish their mission in the 21

century. The

EM spectrum is the only transmission medium adequate to support the mobility,

dispersion, and higher tempo of operations envisioned in JV2020.

Challenges confronting the DoD in realizing its vision of assured EM spectrum access

are a direct result of domestic and international EM spectrum management regulatory

changes and new requirements driven by developments. Congressionally mandated EM

spectrum reallocation, and EM spectrum auctions, increased frequency of international

regulatory actions at the International Telecommunication Union (ITU) World

Radiocommunication Conference (WRC), and world-wide market growth in commercial

wireless usage emphasize the necessity for EM spectrum efficiency, increased

coordination, and strategic planning where DoD can take a proactive posture in

protecting its interest both domestically and internationally.

In addition, the effects of the electromagnetic environment on DoD’s EM spectrum

dependent systems must be carefully analyzed to ensure continued mission effectiveness.

As the EM spectrum becomes more congested the need for an effective DoD E3 program

grows. The adverse effects of the electromagnetic environment (EME) have been

experienced numerous times during Joint and Allied operations, and have endangered

lives, platforms, systems, and equipment. Controlling and minimizing these effects is

crucial for successful accomplishment of the Department's missions. It is our objective to

work the EM spectrum issues in concert with technological approaches to ensure that any

EME effects are transparent to the Warfighters.

1.3 Challenges Affecting DoD’s EM Spectrum Management

1-3

Although the military force structure has downsized considerably since the end of the

Gulf War, operational tempo has increased. A sampling of military operations include:

Operations Provide Comfort, Northern/Southern Watch (Iraq), Operation Provide

Promise and Operation Joint Endeavor in Bosnia and Herzegovina, humanitarian relief

operations in Operation Support Hope in Rwanda, Operation Restore Hope in Somalia,

Operation Allied Force in Kosovo, counter-drug Operations, and humanitarian aid for

disaster, flood, and other natural disasters, and most recently Operation Nobel Eagle and

Enduring Freedom. The DoD projects an increase in worldwide operations in support of

homeland security. To meet these obligations with the present force structure, the DoD

must increase its reliance on force multipliers such as increased automation, smarter

weapons, and near real-time situational awareness. These approaches require a far

greater reliance on rapid, sustained information transfer than in the past.

Growth in commercial wireless applications (i.e. cellular, Personal Communications

System, paging, mobile telephony, broadcast and others) worldwide has also placed

increasing pressures on DoD. Future military information superiority requirements

introduce technical developments in areas such as passive and active sensing, high-speed

data links, high-resolution radars, wideband mobile links, and antenna technology. Some

examples of such technical developments are the unmanned aerial vehicle (UAV) and

network centric operations. UAVs can find, identify, and even direct precision munitions

to a target of interest. They can also collect and relay tactical and strategic intelligence.

Network centric operations enhance the common operating picture of the Warfighter with

tremendous improvements in information sharing made possible by networking. Because

of these desired capabilities, military systems find themselves sometimes in direct

competition for use of certain portions of the EM spectrum with commercial wireless

applications.

Congressionally mandated EM spectrum reallocations of some critical DoD’s EM

spectrum have challenged DoD and become a concern in terms of future EM spectrum

availability for operational training and testing. Title VI of the Omnibus Budget

Reconciliation Act (OBRA-93) required the Secretary of Commerce to provide at least

200 MHz of Government allocated EM spectrum for reallocation. Title III of the

Balanced Budget Act of 1997 (BBA 97) required that the Federal Communications

Commission (FCC) and National Telecommunications and Information Administration

(NTIA) identify for auction at least 120 MHz of additional EM spectrum (20 MHz of

which had to be “Government” EM spectrum). The loss of government EM spectrum has

reduced the flexibility critical to operations and training for the DoD. The prospect of

future reallocations only serves to exacerbate these problems. This has challenged DoD

to pursue proactive approaches that would prevent future erosion of critical government

EM spectrum and technologies that preserve the operational flexibility needed by

Warfighters to complete their mission.

This strategic plan establishes goals and objectives along with specific initiatives to

guide the DoD toward achieving its EM spectrum vision. The DoD EM spectrum and E3

1-4

communities must continue to support changing warfighting concepts and support the

fielding of new commercial and military systems. DoD must pursue regulations and

procedures to ensure EM spectrum supportability. DoD must expand its participation in

international and national EM spectrum decision forums to identify and resolve potential

issues at their onset before they become serious problems. DoD must prioritize planning,

programming, and resources to meet technology changes.

2-1

Section 2

DoD EM Spectrum Management Strategic Goals

This section presents the DoD’s EM spectrum management and E3 goals and

associated objectives, which emphasize DoD’s approach towards achievement of

JSV2010. This plan is designed to provide a streamlined, focused, and coordinated DoD

effort, to ensure access to sufficient EM spectrum needed for realization of JV2020.

1. Goal: - Improve EM spectrum management and E3 business

processes

Access to EM spectrum is essential to the success of military operations and is the

preeminent objective of DoD EM spectrum management. The DoD must develop

improved business processes to successfully meet its present and future EM spectrum

needs, and ensure that systems are free of unintentional adverse effects from the

electromagnetic environment.

Objective 1: Obtain user EM spectrum dependent system requirements.

Strategy: Conduct a thorough end-to-end assessment of systems needs, including

technology trend and evolution. Document baseline user EM spectrum dependent system

requirements for current and future DoD systems. Develop a process and establish

parameters to periodically update baseline requirements.

Target: Identify and document all validated DoD user EM spectrum dependent system

requirements. Maximize the identification and documentation of demonstration program

requirements, for the purpose of quantifying and qualifying EM spectrum supportability.

Objective 2: Translate user needs to EM spectrum requirements.

Strategy: Develop and implement a dynamic and repeatable process to translate user

requirements to EM spectrum requirements.

2-2

Target: Review all Mission Needs Statements (MNSs), Capstone Requirements

Documents (CRDs), Operational Requirements Documents (ORDs) and acquisition

documents and participate in Request For Proposal (RFP) development and system

acquisition process to determine EM spectrum required to support user requirements.

Objective 3: Assess and pursue EM spectrum supportability for user requirements.

Strategy: Participation in the Overarching Integrated Product Team (IPT) and Working-

level IPT to ensure that EM spectrum supportability and E3 requirements are addressed

in the acquisition process.

Target: Review all Command, Control, Communications, Computers, Intelligence,

Surveillance and Reconnaissance (C4ISR) supportability plans for EM spectrum

requirements for all DoD systems.

Objective 4: Identify and document E3 and EM Spectrum Certification (SC)

requirements early on during the Requirements Generation, Planning Programming and

Budgeting System (PPBS) and acquisition processes to determine their impact on the

DoD mission.

Strategy: Evaluate and assess programs during the life-cycle phases of the acquisition

process based on existing E3 and SC policies and procedures, and provide resolution to

program managers on potential issues. Provide the warfighter with an E3 and SC

Limitations and Vulnerabilities Report for each program.

Target: DoD program managers address EM spectrum certification and E3 issues at

each milestone.

Objective 5: Ensure identification and timely submission of host nation EM spectrum

support requests early in the acquisition cycle.

Strategy: Update DoD Directive 4650.1 so that it is consistent with the revised DoD

5000 series. Partner with the requirements and acquisition communities to ensure EM

2-3

spectrum supportability requirements and host nation approval are addressed and

submitted in a timely manner.

Target: All EM spectrum dependent systems operating outside of the United States and

its Possessions (OUS&P) have documented requests for host nation support; DoD

program managers address host nation approval at each milestone for all EM spectrum

dependent systems.

Objective 6: Plan for long-term EM spectrum requirements based on required

capabilities in an integrated and coordinated approach.

Strategy: Coordinate and ensure joint EM spectrum management strategic planning,

including analysis of long-term EM spectrum requirements and forecasts, and evaluate

the means to satisfy these requirements.

Target: Develop a plan of action to satisfy and integrate all DoD long-term EM

spectrum requirements.

Objective 7: Associate EM spectrum requirements with C4ISR architectures.

Strategy: Incorporate identified current and future EM spectrum requirements into

C4ISR support plans.

Target: Incorporate EM spectrum requirements for C4ISR systems into the C4ISR

architecture.

Objective 8: Develop an integrated DoD EM spectrum Architecture to support the joint

environment.

Strategy: Document long-range EM spectrum requirements and balance identified EM

spectrum requirements with EM spectrum availability.

2-4

Target: Map out DoD operational requirements with projected EM spectrum

accessibility.

Objective 9: Enhance coordination between the DoD EM spectrum management

organizations.

Strategy: Promote open dialogue sessions and improve existing problem resolution

processes within the EM spectrum management community.

Target: Streamlined coordination processes, and improved dialogue amongst DoD

frequency management organizations.

2. Goal: - Improve EM spectrum utilization through technological

innovation

As the demand for access to limited EM spectrum continues to grow, means must be

developed for efficient utilization of this resource. The DoD must leverage its research,

development and test resources and promote technology as a key enabler to improve EM

spectrum efficiency.

Objective 1: Pursue technological innovations to improve EM spectrum utilization.

Strategy: Require incorporation of EM spectrum efficient technology into all future

DoD systems.

Target: Increased efficient utilization of EM spectrum as a result of improved

technology.

Objective 2: Encourage partnerships with industry and the civil community to develop

new and efficient techniques for EM spectrum sharing.

2-5

Strategy: Encourage cooperative research efforts between government, industry and

academia through conferences and forums.

Target: Improved efficient EM spectrum sharing techniques to meet future DoD EM

spectrum requirements.

Objective 3: Encourage and support the development and adoption of equipment

standards that afford mutually compatible EM spectrum access and sharing between

government and non-government users.

Communication Interoperability

Strategy: Develop and adopt common standards for EM spectrum dependent equipment.

Target: Improved standards to increase EM spectrum sharing and efficiency.

Objective 4: Improve operational EM spectrum management decision support processes

in dynamic environments.

Strategy: Invest in new technologies to increase EM spectrum battlespace awareness,

and enhance EM spectrum management systems performance and information exchange

across various platforms.

2-6

Target: Increase efficiencies and capabilities of EM spectrum databases and automation

capabilities.

3. Goal: - Promote EM spectrum and E3 awareness and education

To ensure spectrum managers, users, operators, military planners, policy makers,

legislators and EM spectrum regulators are aware of EM spectrum and E3 policies and

procedures, the DoD must actively pursue educational programs that focus and augment

EM spectrum awareness in the areas of military planning, system acquisition, and

integrated joint or coalition operations.

Objective 1: Implement educational programs and appropriate training to increase

awareness of EM spectrum and E3.

Strategy: Target audiences that need EM spectrum management and E3 awareness,

develop and implement training programs for frequency/EM spectrum managers,

users/operators, military planners, and provide EM spectrum and E3 awareness to system

acquisition program managers.

Target: Increased EM spectrum and E3 awareness in the acquisition and operational

communities.

Objective 2: Promote awareness of DoD’s EM spectrum requirements and positions on

EM spectrum issues to policy makers, legislators and EM spectrum regulators.

Strategy: Develop and implement national and international programs to increase

awareness of DoD’s EM spectrum requirements.

Target: Policy makers, legislators and EM spectrum regulators are fully aware of DoD’s

EM spectrum requirements and position.

2-7

4. Goal: - Advocate and defend DoD’s EM Spectrum needs in National

and International EM Spectrum Forums

DoD’s current and future EM spectrum needs are driven by the nation’s interests to potentially include

civil and commercial EM spectrum needs both nationally and internationally. Determining these needs and

articulating them into a National Spectrum Strategy will promote coordination of EM spectrum

requirements, increased compatibility, interoperability, and shared access.

Objective 1: Develop a comprehensive EM spectrum use plan.

Strategy: Document the need for DoD’s current and future EM spectrum requirements.

Identify mission impacts where EM spectrum is not available. Emphasize the importance

of national security requirements and homeland security requirements, when balancing

EM spectrum needs with public safety, and the nation’s economic interests.

Target: Incorporation of DoD’s long-range spectrum requirements into Federal and National Spectrum use

plans.

Objective 2: Promote DoD's positions through the national and international EM

spectrum processes.

Strategy: Build and maintain a strong technical team and foster coalition. Partner with

industry and allies and appropriate national and international EM spectrum

representatives to articulate DoD EM spectrum requirements and positions.

Target: Enhance DoD’s ability to secure required amount of EM spectrum.

2-8

3-1

Section 3

Summary

This Plan outlines the key Goals and Objectives to improving EM spectrum

management business practices, EM spectrum planning, efficient EM spectrum

utilization and coordination with E3 programs. To accomplish these Goals, the DoD will

develop appropriate implementation plans for each of the objectives within this plan.

Effective and timely implementation of these plans will assist the DoD towards realizing

its vision of EM spectrum access in the 21

century.

3-2

Section 4

GLOSSARY

Assured spectrum access: Access to the spectrum required to afford the full capability of

the battlefield electronic systems integral to the success of modern military operations.

Electromagnetic Environmental Effects (E3): The impact of the electromagnetic

environment (EME) upon the operational capability of military forces, equipment, systems,

and platforms. It encompasses all electromagnetic disciplines including Electromagnetic

Compatibility (EMC); Electromagnetic Interference (EMI); Electromagnetic Vulnerability

(EMV); Electromagnetic Pulse (EMP); Electronic Protection; Hazards of Electromagnetic

Radiation to Personnel (HERP), Ordnance (HERO), and Volatile Materials; and natural

phenomena effects of lightning and p-static.

E3 Business process: The programmatic efforts undertaken to ensure that E3 control is

effectively integrated into National Security Systems and Information Technology Systems.

These life-cycle efforts include budgeting for E3 design, test, and evaluation; defining E3

performance requirements; developing test and evaluation strategy; performing analysis and

tests; and documenting system limitations and vulnerabilities.

Electromagnetic Environment (EME): The composite electromagnetic energy, including

man-made and natural sources, to which a system or subsystem/equipment will be exposed in

performing its mission. When defined, the environment will be for a particular time and

place.

Electromagnetic (EM) spectrum: The range of radio frequencies of electromagnetic

radiation from 3kHz to 300GHz.

Electromagnetic spectrum allocation: The designation of frequency bands for use in

performing specific telecommunication functions and services. Also called frequency

allocation.

4-1

Electromagnetic spectrum assignment: The authorization granted by an administration for

a radio station to use a radio frequency channel under specified conditions. Also called

frequency assignment.

Electromagnetic spectrum certification: The process by which the development or

procurement of spectrum dependent systems will be reviewed and approved for compliance

with spectrum management policies, allocations, regulations, and technical standards to

ensure that radio-frequency spectrum is available. Also called spectrum certification (SC).

Full Spectrum Dominance: The synergy of new operational concepts of dominant

maneuver, precision engagement, full dimensional protection, and focused logistics, to

enable the US Armed Forces to dominate the full range of military operations from

humanitarian assistance, through peace operations, up to and into the highest intensity

conflict.

Host Nation Authorization: The mechanism for initiating frequency supportability within

DoD through submission of DD Form 1494, Application for Equipment Frequency

Allocation, by the developing program office (PO) program manager (PM) to the frequency

management office of the pertinent military service.

Spectrum Dependent Systems: Systems that require, operate in, or effect the radio

frequency electromagnetic spectrum.

Spectrum Management Business Processes: The processes that DoD Spectrum

management organizations perform in the day-to-day management of the DoD spectrum.

Spectrum Management: Planning, coordinating, and managing joint use of the

electromagnetic spectrum through operational, engineering, and administrative procedures,

with the objective of enabling electronic systems to perform their functions in the intended

environment without causing or suffering unacceptable interference

Telecommunication: Any transmission, emission, or reception of signs, signals, writings,

images, sounds, or information of any nature by wire, radio, visual, or other electromagnetic

compatible systems.

4-2

Glossary

Acronyms

3G Third Generation

AAG Aeronautical Assignment Group

ACICIP Advisory Committee for International Communications and Information

Policy

ACP Allied Communications Publication

AD Analog to Digital

AFC Area Frequency Controller

AFCA Air Force Communications Agency

AFFMA Air Force Frequency Management Agency

AFI Air Force Instruction

AFMAN Air Force Manual

AM Amplitude Modulation

APEC Asia-Pacific Economic Cooperation

AR Army Regulation

ARNS Aeronautical Radionavigation Service

ARSA Air Route Surveillance Radar

ASD(C3I) Assistant Secretary of Defense (Command, Control, Communications, and

Intelligence)

ASD(NI2) Assistant Secretary of Defense (Networks and Information Integration)

ASMO Army Spectrum Management Office

ATCRBS Air Traffic Control Beacons

AWACS Airborne Warning and Control System

BBA 97 Balanced Budget Act of 1997

BBG Broadcast Board of Governors

BER Bit Error Ratio

BR Radiocommunication Bureau

BSM Battlespace Spectrum Management

CB Citizen Band

CCEB Combined Communications Electronics Board

CCTV closed circuit television

CDD Capabilities Development Document

CDMA Code Division Multiple Access

CEOI Communications Electronics Operation Instruction

CIO chief information officer

GL-1

CIP International Communications and Information Policy

CIP/BA International Communications and Information Policy Office of Bilateral

Affairs

CIP/MA International Communications and Information Policy Office of

Multilateral Affairs

CIP/SP International Communications and Information Policy Office of Strategic

Planning and Satellite Policy

CITEL Commission for Inter-American Telecommunications

CJCSI Chairman of the Joint Chiefs of Staff Instruction

CJCSM Chairman of the Joint Chiefs of Staff Manual

COMSATCOM Commercial Satellite Communications

CONUS Continental United States

COTS Commercial Off-The-Shelf

CPD Capabilities Production Document

CPM Conference Preparatory Meeting

CR Cognitive Radio

CSMA Carrier Sense Multiple Access

DA Digital to Analog

DAB Digital Audio Broadcast

DASD Deputy Assistant Secretary of Defense

dB Decibel

DDN Defense Data Network

DFS Dynamic Frequency Selection

DISA Defense Information Systems Agency

DME Distance Measuring Equipment

DoC Department of Commerce

DoD Department of Defense

DoS Department of State

DSN Defense Switched Network

DSO Defense Spectrum Office

DSP Digital Signal Processing

DSSS Direct Sequence Spread Spectrum

DoT Department of Transportation

E3 Electromagnetic Environmental Effect

EB DoS Bureau of Economic and Business Affairs

EHF Extremely High Frequency

EIM External Intermodulation Distortion

ELF Extremely Low Frequency

EM Electromagnetic

GL-2

EMC Electromagnetic Compatibility

EME Electromagnetic Environment

EMI Electromagnetic Interference

EPS Emergency Planning Subcommittee

ESGPWG Equipment Spectrum Guidance Permanent Working Group

EW Electronic Warfare

FAA Federal Aviation Administration

FAS Frequency Assignment Subcommittee

FCC Federal Communications Commission

FEC Forward Error Correction

FFT Fast Fourier transform

FM Frequency Modulation

FMRS Frequency Management Records System

FOC Final Operational Capability

FP Frequency Panel (MCEB)

FRC Federal Radio Commission

FRP Full-Rate Production

FWA Fixed Wireless Access

GEMSIS Global Electromagnetic Spectrum Information System

GHz Gigahertz (10

)

GMF Government Master File

GPS Global Positioning System

GSO Geo-Synchronous Orbit

HF High Frequency

HNA Host Nation Approval

HNSWD Host Nation Spectrum Worldwide Database

Hz Hertz

ICC Interstate Commerce Commission

ICD Initial Capabilities Document

IEEE Institute of Electrical and Electronics Engineers

IF Intermediate Frequency

IFF Identification, Friend or Foe

IFRB International Frequency Registration Board

ILS DEFINE

IM Intermodulation

IMT-2000 International Mobile Telecommunications 2000

INMARSAT International Maritime Satellite Organization

GL-3

INTELSAT International Telecommunications Satellite Organization

IOC Initial Operational Capability

IPWG International Permanent Working Group

IRAC Interdepartment Radio Advisory Committee

ISDN Integrated Service Digital Network

ISM Industrial, Scientific, and Medical

ITAC International Telecommunications Advisory Committee

ITAC-D International Telecommunications Advisory Committee-

Telecommunications Development Sector

ITAC-R International Telecommunications Advisory Committee-

Radiocommuncations Sector

ITAC-T International Telecommunications Advisory Committee-

Telecommunications Standardization Sector

ITU International Telecommunications Union

ITU-R International Telecommunication Union – Radiocommunications Sector

JCEOI Joint Communications Electronics Operation Instruction

JCEOI PWG Joint Communications-Electronics Operation Instructions Permanent

Working Group

JCIDS Joint Capabilities Integration and Development System

JFMO Joint Frequency Management Office

JRFL Joint Restricted Frequency List

JSC Joint Spectrum Center

JSIR Joint Spectrum Interference Resolution

JSME Joint Spectrum Management Entity

JSV Joint Spectrum Vision

JTIDS Joint Tactical Information Distribution System

JTRS Joint Tactical Radio System

kHz Kilohertz (10

)

LAN Local Area Network

LF Low Frequency

LMR Land Mobile Radio

LMR PWG Land Mobile Radio Permanent Working Group

LOS Line Of Sight

MAG Military Assignment Group

MANET Mobile Ad Hoc Network

MARS Military Affiliate Radio System

GL-4

MCO Marine Corps Order

MHz Megahertz (10

)

MIDS Multifunctional Information Distribution System

MILSATCOM Military Satellite Communications

MOA Memorandum of Agreement

MRFL Master Radio Frequency List

MSE Mobile Subscriber Equipment

MSS Mobile Satellite Service

NASA National Aeronautical Space Administration

NATO North Atlantic Treaty Organization

NDAA National Defense Authorization Act

NGSO Non-Geosynchronous Orbit

NIB Non-interference basis

NII National Information Infrastructure

NMSC Navy Marine Corp Spectrum Center

NSEP National Security Emergency Preparedness

NTIA National Telecommunications and Information Administration

OASD Office of the Assistant Secretary of Defense

OBRA 93 Omnibus Budget Reconciliation Act of 1993

OCONUS Outside the Continental United States

OECD Organization for Economic Cooperation and Development

OET Office of Engineering and Technology

OFDM Orthogonal Frequency Division Multiplexing

OPNAVINST Staff of the Chief of Naval Operations Instruction

OSM Office of Spectrum Management

OTP Office of Telecommunications Policy

PAM Pulse Amplitude Modulation

PCM Pulse Code Modulation

PCS Personal Communications System

PN Pseudo Noise

PPM Pulse Position Modulation

PSTN Public Switched Telephone System

PWG Permanent Working Group

PWM Pulse Width Modulation

RADAR Radio Detection and Ranging

RBECS Revised Battlefield Electronic CEOI System

GL-5

RCS Radio Conference Subcommittee

RDT&E Research, Development, Test, and Evaluation

RF Radio Frequency

RIM Receiver intermodulation distortion

RLAN Radio Local Area Network

RR Radio Regulations

RRB Radio Regulations Board

SATCOM Satellite Communications

SCS Spectrum Certification System

SDR Software Defined Radio

SDRSM PWG Software Defined Radio Spectrum Management Permanent Working

Group

SG Study Group

SHF DEFINE

SIF Selective Identification Feature

SM Spectrum Management

SMA PWG Spectrum Management Architecture Permanent Working Group

SMO Spectrum Management Office

SMRG Spectrum Management Review Group

SNR Signal to Noise Ratio

SO PWG Spectrum Operation Permanent Working Group

SPAC Spectrum Planning and Advisory Committee

SPS Spectrum Planning Subcommittee

SSPWG Space System Permanent Working Group

SSS Space System Subcommittee

T&E Test and Evaluation

TCAS Traffic Alert and Collision Avoidance System

TG Task Group

THz Terahertz (10

)

TIM Transmitter Intermodulation distortion

TPC Transmitter Power Control

TSC Technical Subcommittee

TV Television

UAT Universal Access Transceiver

UAV Unmanned Air Vehicle

UHF Ultra High Frequency

U-NII Unlicensed National Information Infrastructure

US&P United States and its Possessions

GL-6

USA CESO U.S. Army Communications Electronics Services Organization

USCG United States Coast Guard

USMCEB United States Military Communications-Electronics Board

UTC Coordinated Universal Time

UWB Ultra Wideband

VHF Very High Frequency

VLF Very Low Frequency

WARC World Administrative Radiocommunication Conference

WiFi Wireless Fidelity (IEEE 802.11)

WLAN Wireless Local Area Network

WNW Wideband Networking Waveform

WRC World Radiocommunication (or Radio) Conference

WSUPT Warfighter Spectrum Usage Planning Tool

GL-7

Terms

The sources of term definitions are provided in parenthesis. When the definitions from

two sources are the same we noted the source as the higher precedence document. For

example, many of the definitions in NTIA’s Red Book are the same as those in the ITU’s

Radio Regulations. We site only the ITU Radio Regulations as the source. The following

reference abbreviations for the definition source were used:

(RR) - ITU’s Radio Regulations

(NTIA) - NTIA’s Red Book

(IEEE Std 100-1992). The New IEEE Standard Dictionary of Electrical and Electronics

Terms

(DoDD 4650.1) DoDD 4650.1, “Electromagnetic Spectrum – Management and Use”

absorption (radio wave propagation). The irreversible conversion of the energy of an

electromagnetic wave into another form of energy as a result of wave interaction with

matter. (IEEE Std 100-1992)

accepted interference. Interference at a higher level than that defined as permissible

interference and which has been agreed upon between two or more administrations

without prejudice to other administrations. (RR)

active satellite. A satellite carrying a station intended to transmit or retransmit

radiocommunication signals. (RR)

active sensor. A measuring instrument in the earth exploration-satellite service or in the

space research service by means of which information is obtained by transmission and

reception of radio waves. (RR)

adaptive system. A radiocommunication system which varies its radio characteristics

according to channel quality. (RR)

administration. Any governmental department or service responsible for discharging the

obligations undertaken in the constitution of the International Telecommunication Union,

in the convention of the International Telecommunication Union and in the

Administrative Regulations (RR)

aeronautical earth station. An earth station in the fixed-satellite service, or, in some cases,

in the aeronautical mobile-satellite service, located at a specified fixed point on land to

provide a feeder link for the aeronautical mobile-satellite service. (RR)

aeronautical mobile off-route (OR)

service. An aeronautical mobile service intended for

communications, including those relating to flight coordination, primarily outside

national or international civil air routes. (RR)

GL-8

aeronautical mobile route (R) service. An aeronautical mobile service reserved for

communications relating to safety and regularity of flight, primarily along national or

international civil air routes. (RR)

aeronautical mobile service. A mobile service between aeronautical stations and aircraft

stations, or between aircraft stations, in which survival craft stations may participate;

emergency position-indicating radiobeacon stations may also participate in this service

on designated distress and emergency frequencies. (RR)

aeronautical mobile-satellite (OR)

service. An aeronautical mobile-satellite service

intended for communications, including those relating to flight coordination, primarily

outside national and international civil air routes. (RR)

aeronautical mobile-satellite R (R)

service An aeronautical mobile-satellite service

reserved for communications relating to safety and regularity of flights, primarily along

national or international civil air routes. (RR)

aeronautical mobile-satellite service. A mobile-satellite service in which mobile earth

stations are located on board aircraft; survival craft stations and emergency position-

indicating radiobeacon stations may also participate in this service. (RR)

aeronautical radionavigation service. A radionavigation service intended for the benefit

and for the safe operation of aircraft. (RR)

aeronautical radionavigation-satellite service. A radionavigation-satellite service in which

earth stations are located on board aircraft. (RR)

aeronautical station. A land station in the aeronautical mobile service.

In certain instances, an aeronautical station may be located, for example, on board a ship

or on a platform at sea. (RR)

aircraft earth station. A mobile earth station in the aeronautical mobile-satellite service

located on board an aircraft. (RR)

aircraft station. A mobile station in the aeronautical mobile service, other than a survival

craft station, located on board an aircraft. (RR)

allocation (of a frequency band). Entry in the Table of Frequency Allocations of a given

frequency band for the purpose of its use by one or more terrestrial or space

radiocommunication services or the radio astronomy service under specified conditions.

This term shall also be applied to the frequency band concerned. (RR)

allotment (of a radio frequency or radio frequency channel). Entry of a designated

frequency channel in an agreed plan, adopted by a competent conference, for use by one

or more administrations for a terrestrial or space radiocommunication service in one or

more identified countries or geographical areas and under specified conditions. (RR)

GL-9

altitude of the apogee or of the perigee. The altitude of the apogee or perigee above a

specified reference surface serving to represent the surface of the Earth. (RR)

amateur service A radiocommunication service for the purpose of self-training,

intercommunication and technical investigations carried out by amateurs, that is, by duly

authorized persons interested in radio technique solely with a personal aim and without

pecuniary interest. (RR)

amateur station. A station in the amateur service. (RR)

amateur-satellite service. A radiocommunication service using space stations on earth

satellites for the same purposes as those of the amateur service. (RR)

assigned frequency. The center of the frequency band assigned to a station. (RR)

assigned frequency band. The frequency band within which the emission of a station is

authorized; the width of the band equals the necessary bandwidth plus twice the absolute

value of the frequency tolerance. Where space stations are concerned, the assigned

frequency band includes twice the maximum Doppler shift that may occur in relation to

any point of the Earth's surface. (RR)

assignment (of a radio frequency or radio frequency channel). Authorization given by an

administration for a radio station to use a radio frequency or radio frequency channel

under specified conditions. (RR)

attenuation (of an electromagnetic wave). The decrease in amplitude of a field with the

distance or with changes in the propagation path in excess of the decrease due to

geometrical spreading. (IEEE Std 100-1992)

authorized bandwidth. The necessary bandwidth required for transmission and reception of

intelligence (does not include allowance for transmitter drift and Doppler shift) (NTIA)

base earth station. An earth station in the fixed-satellite service or, in some cases, in the

land mobile-satellite service, located at a specified fixed point or within a specified area

on land to provide a feeder link for the land mobile-satellite service. (RR)

base station. A land station in the land mobile service. (RR)

broadcasting service. A radiocommunication service in which the transmissions are

intended for direct reception by the general public. This service may include sound

transmissions, television transmissions or other types of transmission (CS). (RR)

broadcasting station. A station in the broadcasting service. (RR)

broadcasting-satellite service. A radiocommunication service in which signals transmitted

or retransmitted by space stations are intended for direct reception by the general public.

GL-10

In the broadcasting-satellite service, the term “direct reception” shall encompass both

individual reception and community reception. (RR)

carrier power (of a radio transmitter). The average power supplied to the antenna

transmission line by a transmitter during one radio frequency cycle taken under the

condition of no modulation. (RR)

characteristic frequency. A frequency which can be easily identified and measured in a

given emission.

A carrier frequency may, for example, be designated as the characteristic frequency. (RR)

class of emission. The set of characteristics of an emission, designated by standard symbols,

e.g., type of modulation of the main carrier, modulating signal, type of information to be

transmitted, and also, if appropriate, any additional signal characteristics. (RR)

coast earth station. An earth station in the fixed-satellite service or, in some cases, in the

maritime mobile-satellite service, located at a specified fixed point on land to provide a

feeder link for the maritime mobile-satellite service. (RR)

coast station. A land station in the maritime mobile service. (RR)

cognitive radio. A radio frequency transmitter/receiver that is designed to intelligently

detect whether a particular segment of the radio spectrum is currently in use, and to jump

into (and out of, as necessary) the temporarily-unused spectrum very rapidly, without

interfering with the transmissions of other authorized users. (IEEE USA Position on

Improving Spectrum Usage Through Cognitive Radio Technology)

community reception (in the broadcasting-satellite service). The reception of emissions

from a space station in the broadcasting-satellite service by receiving equipment, which

in some cases may be complex and have antennae larger than those used for individual

reception, and intended for use:

by a group of the general public at one location; or •

• through a distribution system covering a limited area. (RR)

coordinated universal time (UTC). Time scale, based on the second (SI), as defined in

ITU-R Recommendation ITU-R TF.460-5. For most practical purposes associated with

the Radio Regulations, UTC is equivalent to mean solar time at the prime meridian (0°

longitude), formerly expressed in GMT. (RR)

coordination area. When determining the need for coordination, the area surrounding an

earth station sharing the same frequency band with terrestrial stations, or surrounding a

transmitting earth station sharing the same bidirectionally allocated frequency band with

receiving earth stations, beyond which the level of permissible interference will not be

exceeded and coordination is therefore not required. (RR)

GL-11

coordination contour. The line enclosing the coordination area. (RR)

coordination distance. When determining the need for coordination, the distance on a given

azimuth from an earth station sharing the same frequency band with terrestrial stations, or

from a transmitting earth station sharing the same bidirectionally allocated frequency

band with receiving earth stations, beyond which the level of permissible interference

will not be exceeded and coordination is therefore not required. (RR)

deep space. Space at distances from the Earth equal to, or greater than, 2 × 10

km. (RR)

decibel. A standard unit for expressing the ratio between two parameters using logarithms to

the base 10. Decibels provide a convenient format to express voltages or powers that

range several orders of magnitude for a given system. (IEEE Std 100-1992)

diffraction (radio-wave propagation). The deviation of the direction of energy flow of a

wave, not attributable to reflection and or refraction, when it passes an obstacle, a

restricted aperture, or other inhomogeneities in a medium. (IEEE Std 100-1992)

duplex operation. Operating method in which transmission is possible simultaneously in

both directions of a telecommunication channel

. (RR)

earth exploration-satellite service. A radiocommunication service between earth stations

and one or more space stations, which may include links between space stations, in

which:

•

information relating to the characteristics of the earth and its natural phenomena,

including data relating to the state of the environment, is obtained from active sensors

or passive sensors on earth satellites;

similar information is collected from airborne or earth-based platforms;

such information may be distributed to earth stations within the system concerned;

platform interrogation may be included.

This service may also include feeder links necessary for its operation. (RR)

earth station. A station located either on the Earth's surface or within the major portion of

the earth's atmosphere and intended for communication:

with one or more space stations; or

In general, duplex operation and semi-duplex operation require two frequencies in radiocommunication;

simplex operation may use either one or two.

GL-12

with one or more stations of the same kind by means of one or more reflecting

satellites or other objects in space. (RR)

•

effective antenna gain contour (of a steerable satellite beam). An envelope of antenna gain

contours resulting from moving the boresight of a steerable satellite beam along the

limits of the effective boresight area. (RR)

effective boresight area (of a steerable satellite beam). An area on the surface of the Earth

within which the boresight of a steerable satellite beam is intended to be pointed.

There may be more than one unconnected effective boresight area to which a single

steerable satellite beam is intended to be pointed. (RR)

effective monopole radiated power (e.m.r.p.) (in a given direction). The product of the

power supplied to the antenna and its gain relative to a short vertical antenna in a given

direction. (RR)

effective radiated power (e.r.p.) (in a given direction). The product of the power supplied

to the antenna and its gain relative to a half-wave dipole in a given direction. (RR)

electromagnetic compatibility (EMC). The condition that prevails when

telecommunications equipment is performing its individually designed function in a

common electromagnetic environment without causing or suffering unacceptable

degradation due to unintentional electromagnetic interference (EMI) to or from other

equipment in the same environment. (NTIA) The ability of systems, equipment, and

devices that utilize the electromagnetic spectrum to operate in their intended operational

environments without suffering unacceptable degradation or causing unintentional

degradation because of electromagnetic radiation or response. It involves the application

of sound electromagnetic spectrum management; system, equipment, and device design

configuration that ensures interference-free operation; and clear concepts and doctrines

that maximize operational effectiveness. (4650.1)

electromagnetic interference (EMI). Any electromagnetic disturbance that interrupts,

obstructs, or otherwise degrades or limits the effective performance of electronics or

electrical equipment. It can be induced intentionally, as in some forms of electronic

warfare, or unintentionally, as a result of spurious emissions and responses,

intermodulation products, and the like.

emergency position-indicating radiobeacon station. A station in the mobile service the

emissions of which are intended to facilitate search and rescue operations. (RR)

emission. Radiation produced, or the production of radiation, by a radio transmitting station.

For example, the energy radiated by the local oscillator of a radio receiver would not be

an emission but a radiation. (RR)

GL-13

equipment spectrum certification. The statement(s) of adequacy received from authorities

of sovereign nations after their review of the technical characteristics of a spectrum-

dependent equipment or system regarding compliance with their national spectrum

management policy, allocations, regulations, and technical standard. Equipment

spectrum certification is alternately called “spectrum certification.” (4650.1)

equivalent isotropically radiated power (e.i.r.p.). The product of the power supplied to the

antenna and the antenna gain in a given direction relative to an isotropic antenna

(absolute or isotropic gain). (RR)

equivalent satellite link noise temperature. The noise temperature referred to the output of

the receiving antenna of the earth station corresponding to the radio frequency noise

power which produces the total observed noise at the output of the satellite link excluding

noise due to interference coming from satellite links using other satellites and from

terrestrial systems. (RR)

experimental station. A station utilizing radio waves in experiments with a view to the

development of science or technique.

This definition does not include amateur stations. (RR)

facsimile. A form of telegraphy for the transmission of fixed images, with or without half-

tones, with a view to their reproduction in a permanent form. (RR)

fading. (radio-wave propagation). The temporal variation of received signal power caused

by changes in the transmission medium or path(s). (IEEE Std 100-1992)

feeder link. A radio link from an earth station at a given location to a space station, or vice

versa, conveying information for a space radiocommunication service other than for the

fixed-satellite service. The given location may be at a specified fixed point, or at any

fixed point within specified areas. (RR)

filter. A transducer for separating waves on the basis of their frequency. (IEEE Std 100-

1992)

fixed service. A radiocommunication service between specified fixed points. (RR)

fixed station. A station in the fixed service. (RR)

fixed-satellite service. A radiocommunication service between earth stations at given

positions, when one or more satellites are used; the given position may be a specified

fixed point or any fixed point within specified areas; in some cases this service includes

satellite-to-satellite links, which may also be operated in the inter-satellite service; the

fixed-satellite service may also include feeder links for other space radiocommunication

services. (RR)

GL-14

frequency (radio-wave propagation). The number of identical cycles per second of a

periodic oscillation or wave. (IEEE Std 100-1992)

frequency tolerance. The maximum permissible departure by the centre frequency of the

frequency band occupied by an emission from the assigned frequency or, by the

characteristic frequency of an emission from the reference frequency.

The frequency tolerance is expressed in parts in 10

or in hertz. (RR)

frequency-shift telegraphy. Telegraphy by frequency modulation in which the telegraph

signal shifts the frequency of the carrier between predetermined values. (RR)

full carrier single-sideband emission. A single-sideband emission without reduction of the

carrier. (RR)

fundamental frequency. (1) (Signal-transmission system) The reciprocal of the period of a

wave. (2)(Mathematically) The lowest frequency component in the Fourier

representation of a periodic quantity. (IEEE Std 100-1992)

gain of an antenna. The ratio, usually expressed in decibels, of the power required at the

input of a loss-free reference antenna to the power supplied to the input of the given

antenna to produce, in a given direction, the same field strength or the same power flux-

density at the same distance. When not specified otherwise, the gain refers to the

direction of maximum radiation. The gain may be considered for a specified polarization.

Depending on the choice of the reference antenna a distinction is made between:

a) absolute or isotropic gain (G

), when the reference antenna is an isotropic antenna

isolated in space;

b) gain relative to a half-wave dipole (G

), when the reference antenna is a half-wave

dipole isolated in space whose equatorial plane contains the given direction;

c) gain relative to a short vertical antenna (G

), when the reference antenna is a linear

conductor, much shorter than one quarter of the wavelength, normal to the surface of

a perfectly conducting plane which contains the given direction. (RR)

geostationary satellite. A geosynchronous satellite whose circular and direct orbit lies in

the plane of the Earth's equator and which thus remains fixed relative to the Earth; by

extension, a satellite which remains approximately fixed relative to the Earth. (RR)

geostationary-satellite orbit. The orbit of a geosynchronous satellite whose circular and

direct orbit lies in the plane of the Earth's equator. (RR)

geosynchronous satellite. An earth satellite whose period of revolution is equal to the

period of rotation of the Earth about its axis. (RR)

GL-15

harmful interference. Interference which endangers the functioning of a radionavigation

service or of other safety services or seriously degrades, obstructs, or repeatedly

interrupts a radiocommunication service operating in accordance with Radio Regulations

(CS). (RR)

harmonic. A sinusoidal component of a periodic wave or quantity having a frequency that is

an integral multiple of the fundamental frequency. (IEEE Std 100-1992)

harmonic distortion. Nonlinear distortion of a system or transducer characerized by the

appearance in the output of harmonics other than the fundamental component when the

input wave is sinusoidal. (IEEE Std 100-1992)

high altitude platform station. A station located on an object at an altitude of 20 to 50 km

and at a specified, nominal, fixed point relative to the Earth. (RR)

inclination of an orbit (of an earth satellite). The angle determined by the plane containing

the orbit and the plane of the Earth’s equator measured in degrees between 0º and 180º

and in counter-clockwise direction from the Earth’s equatorial plane at the ascending

node of the orbit. (RR)

individual reception (in the broadcasting-satellite service). The reception of emissions from

a space station in the broadcasting-satellite service by simple domestic installations and

in particular those possessing small antennae. (RR)

industrial, scientific and medical (ISM) applications (of radio frequency energy).

Operation of equipment or appliances designed to generate and use locally radio

frequency energy for industrial, scientific, medical, domestic or similar purposes,

excluding applications in the field of telecommunications. (RR)

instrument landing system (ILS). A radionavigation system which provides aircraft with

horizontal and vertical guidance just before and during landing and, at certain fixed

points, indicates the distance to the reference point of landing. (RR)

ILS glide path. A system of vertical guidance embodied in the ILS which that indicates the

vertical deviation of the aircraft from its optimum path of descent. (RR)

ILS localizer. A system of horizontal guidance embodied in the ILS which that indicates the

horizontal deviation of the aircraft from its optimum path of descent along the axis of the

runway. (RR)

interference. The effect of unwanted energy due to one or a combination of emissions,

radiations, or inductions upon reception in a radiocommunication system, manifested by

any performance degradation, misinterpretation, or loss of information which could be

extracted in the absence of such unwanted energy. (RR)

GL-16

intermodulation distortion. Nonlinear distortion of a system or transducer characterized by

the appearance of frequencies at the output equal to the sums and differences of integral

multiples of the two or more component frequencies present at the input. (IEEE Std 100-

1992)

inter-satellite service. A radiocommunication service providing links between artificial

satellites. (RR)

ionospheric scatter. The propagation of radio waves by scattering as a result of

irregularities or discontinuities in the ionization of the ionosphere. (RR)

ionospheric sounder. A device that transmits signals for the purpose of determining

ionospheric conditions. (NTIA)

land earth station. An earth station in the fixed-satellite service or, in some cases, in the

mobile-satellite service, located at a specified fixed point or within a specified area on

land to provide a feeder link for the mobile-satellite service. (RR)

land mobile earth station. A mobile earth station in the land mobile-satellite service

capable of surface movement within the geographical limits of a country or continent.

(RR)

land mobile service. A mobile service between base stations and land mobile stations, or

between land mobile stations. (RR)

land mobile station. A mobile station in the land mobile service capable of surface

movement within the geographical limits of a country or continent. (RR)

land mobile-satellite service. A mobile-satellite service in which mobile earth stations are

located on land. (RR)

land station. A station in the mobile service not intended to be used while in motion. (RR)

left-hand (anticlockwise) polarized wave. An elliptically- or circularly-polarized wave, in

which the electric field vector, observed in any fixed plane, normal to the direction of

propagation, whilst while looking in the direction of propagation, rotates with time in a

left-hand or anticlockwise direction. (RR)

maritime mobile service. A mobile service between coast stations and ship stations, or

between ship stations, or between associated on-board communication stations; survival

craft stations and emergency position-indicating radiobeacon stations may also

participate in this service. (RR)

maritime mobile-satellite service. A mobile-satellite service in which mobile earth stations

are located on board ships; survival craft stations and emergency position-indicating

radiobeacon stations may also participate in this service. (RR)

GL-17

maritime radionavigation service. A radionavigation service intended for the benefit and

for the safe operation of ships. (RR)

maritime radionavigation-satellite service. A radionavigation-satellite service in which

earth stations are located on board ships. (RR)

marker beacon. A transmitter in the aeronautical radionavigation service which radiates

vertically a distinctive pattern for providing position information to aircraft. (RR)

mean power (of a radio transmitter) . The average power supplied to the antenna

transmission line by a transmitter during an interval of time sufficiently long compared

with the lowest frequency encountered in the modulation taken under normal operating

conditions. (RR)

meteorological aids service. A radiocommunication service used for meteorological,

including hydrological, observations, and exploration. (RR)

meteorological-satellite service. An earth exploration-satellite service for meteorological

purposes. (RR)

mobile earth station. An earth station in the mobile-satellite service intended to be used

while in motion or during halts at unspecified points. (RR)

mobile service. A radiocommunication service between mobile and land stations, or

between mobile stations (CV). (RR)

mobile station. A station in the mobile service intended to be used while in motion or

during halts at unspecified points. (RR)

mobile-satellite service. A radiocommunication service:

between mobile earth stations and one or more space stations, or between space

stations used by this service; or

•

• between mobile earth stations by means of one or more space stations.

This service may also include feeder links necessary for its operation. (RR)

modulation. A controlled variation with time of any property of a wave for the purpose of

transferring information. (IEEE Std 100-1992)

multi-satellite link. A radio link between a transmitting earth station and a receiving earth

station through two or more satellites, without any intermediate earth station.

A multi-satellite link comprises one up-link, one or more satellite-to-satellite links and

one down-link. (RR)

GL-18

necessary bandwidth. For a given class of emission, the width of the frequency band which

is just sufficient to ensure the transmission of information at the rate and with the quality

required under specified conditions. (RR)

occupied bandwidth. The width of a frequency band such that, below the lower and above

the upper frequency limits, the mean powers emitted are each equal to a specified

percentage β/2 of the total mean power of a given emission.

Unless otherwise specified in an ITU-R Recommendation for the appropriate class of

emission, the value of β/2 should be taken as 0.5%. (RR)

on-board communication station. A low-powered mobile station in the maritime mobile

service intended for use for internal communications on board a ship, or between a ship

and its lifeboats and life-rafts during lifeboat drills or operations, or for communication

within a group of vessels being towed or pushed, as well as for line handling and

mooring instructions. (RR)

orbit. The path, relative to a specified frame of reference, described by the centre of mass of

a satellite or other object in space subjected primarily to natural forces, mainly the force

of gravity. (RR)

out-of-band emission. Emission on a frequency or frequencies immediately outside the

necessary bandwidth which results from the modulation process, but excluding spurious

emissions. (RR)

passive sensor. A measuring instrument in the earth exploration-satellite service or in the

space research service by means of which information is obtained by reception of radio

waves of natural origin. (RR)

peak envelope power (of a radio transmitter). The average power supplied to the antenna

transmission line by a transmitter during one radio frequency cycle at the crest of the

modulation envelope taken under normal operating conditions. (RR)

period (of a satellite). The time elapsing between two consecutive passages of a satellite

through a characteristic point on its orbit. (RR)

permissible interference. Observed or predicted interference which complies with

quantitative interference and sharing criteria contained in these Regulations or in ITU-R

Recommendations or in special agreements as provided for in these Regulations. (RR)

port operations service. A maritime mobile service in or near a port, between coast stations

and ship stations, or between ship stations, in which messages are restricted to those

relating to the operational handling, the movement and the safety of ships, and, in

emergency, to the safety of persons.

GL-19

Messages which that are of a public correspondence nature shall be excluded from this

service. (RR)

port station. A coast station in the port operations service. (RR)

power. Whenever the power of a radio transmitter, etc. is referred to it shall be expressed in

one of the following forms, according to the class of emission, using the arbitrary

symbols indicated:

peak envelope power (PX or pX); •

•

mean power (PY or pY);

carrier power (PZ or pZ).

For different classes of emission, the relationships between peak envelope power, mean

power, and carrier power, under the conditions of normal operation and of no

modulation, are contained in ITU-R Recommendations, which may be used as a guide.

For use in formulae, the symbol p denotes power expressed in watts and the symbol P

denotes power expressed in decibels relative to a reference level. (RR)

primary radar. A radiodetermination system based on the comparison of reference signals

with radio signals reflected from the position to be determined. (RR)

protection ratio (R.F.). The minimum value of the wanted-to-unwanted signal ratio, usually

expressed in decibels, at the receiver input, determined under specified conditions such

that a specified reception quality of the wanted signal is achieved at the receiver output.

(RR)

public correspondence. Any telecommunication which the offices and stations must, by

reason of their being at the disposal of the public, accept for transmission (CS). (RR)

radar. A radiodetermination system based on the comparison of reference signals with radio

signals reflected, or retransmitted, from the position to be determined. (RR)

radar beacon (racon). A transmitter-receiver associated with a fixed navigational mark

which, when triggered by a radar, automatically returns a distinctive signal which can

appear on the display of the triggering radar, providing range, bearing, and identification

information. (RR)

radiation. The outward flow of energy from any source in the form of radio waves. (RR)

radiation hazard (RADHAZ). RADHAZs are of three types. One deals with the effects

on the human body of nonionizing radiation caused by exposure to high-power

transmitters or electronic equipment that produces x-rays. The other types deal with the

danger of RF transmissions accidentally detonating explosive devices or igniting fuels.

GL-20

radio. A general term applied to the use of radio waves. (RR)

radio altimeter. Radionavigation equipment, on board an aircraft or spacecraft, used to

determine the height of the aircraft or the spacecraft above the earth's surface or another

surface. (RR)

radio astronomy. Astronomy based on the reception of radio waves of cosmic origin. (RR)

radio astronomy service. A service involving the use of radio astronomy. (RR)

radio astronomy station. A station in the radio astronomy service. (RR)

radio direction-finding. Radiodetermination using the reception of radio waves for the

purpose of determining the direction of a station or object. (RR)

radio direction-finding station. A radiodetermination station using radio direction-finding.

(RR)

radio waves or hertzian waves. Electromagnetic waves of frequencies arbitrarily lower

than 3,000 GHz, propagated in space without artificial guide. (RR)

radiobeacon station. A station in the radionavigation service the emissions of which are

intended to enable a mobile station to determine its bearing or direction in relation to the

radiobeacon station. (RR)

radiocommunication service. A service as defined in this section involving the

transmission, emission and/or reception of radio waves for specific telecommunication

purposes.

Usually, radiocommunication service relates to terrestrial radiocommunication. (RR)

radiocommunication. Telecommunication by means of radio waves. (RR)

radiodetermination. The determination of the position, velocity and/or other characteristics

of an object, or the obtaining of information relating to these parameters, by means of the

propagation properties of radio waves. (RR)

radiodetermination service. A radiocommunication service for the purpose of

radiodetermination. (RR)

radiodetermination station. A station in the radiodetermination service. (RR)

radiodetermination-satellite service. A radiocommunication service for the purpose of

radiodetermination involving the use of one or more space stations. This service may

also include feeder links necessary for its own operation. (RR)

radiolocation. Radiodetermination used for purposes other than those of radionavigation.

(RR)

GL-21

radiolocation land station. A station in the radiolocation service not intended to be used

while in motion. (RR)

radiolocation mobile station. A station in the radiolocation service intended to be used

while in motion or during halts at unspecified points. (RR)

radiolocation service. A radiodetermination service for the purpose of radiolocation. (RR)

radiolocation-satellite service. A radiodetermination-satellite service used for the purpose

of radiolocation. This service may also include the feeder links necessary for its

operation. (RR)

radionavigation. Radiodetermination used for the purposes of navigation, including

obstruction warning. (RR)

radionavigation land station. A station in the radionavigation service not intended to be

used while in motion. (RR)

radionavigation mobile station. A station in the radionavigation service intended to be

used while in motion or during halts at unspecified points. (RR)

radionavigation service. A radiodetermination service for the purpose of radionavigation.

(RR)

radionavigation-satellite service. A radiodetermination-satellite service used for the

purpose of radionavigation. (RR)

radiosonde. An automatic radio transmitter in the meteorological aids service usually

carried on an aircraft, free balloon, kite or parachute, and which transmits meteorological

data. (RR)

radiotelegram. A telegram, originating in or intended for a mobile station or a mobile earth

station transmitted on all or part of its route over the radiocommunication channels of the

mobile service or of the mobile-satellite service. (RR)

radiotelemetry. Telemetry by means of radio waves. (RR)

radiotelephone call. A telephone call, originating in or intended for a mobile station or a

mobile earth station, transmitted on all or part of its route over the radiocommunication

channels of the mobile service or of the mobile-satellite service. (RR)

radiotelex call. A telex call, originating in or intended for a mobile station or a mobile earth

station, transmitted on all or part of its route over the radiocommunication channels of

the mobile service or the mobile-satellite service. (RR)

reduced carrier single-sideband emission. A single-sideband emission in which the degree

of carrier suppression enables the carrier to be reconstituted and to be used for

demodulation. (RR)

GL-22

reference frequency. A frequency having a fixed and specified position with respect to the

assigned frequency. The displacement of this frequency with respect to the assigned

frequency has the same absolute value and sign that the displacement of the characteristic

frequency has with respect to the center of the frequency band occupied by the emission.

(RR)

reflected wave (radio-wave propagation). For two media, separated by a planar interface,

that part of the incident wave which is returned to the first medium. (IEEE Std 100-1992)

reflecting satellite. A satellite intended to reflect radiocommunication signals. (RR)

refraction (radio-wave propagation). The change in direction of propagation of a traveling

wave resulting from the spatial variation of refractive index of the medium. (IEEE Std

100-1992)

restricted radiation device. A device in which the generation of RF energy is intentionally

incorporated into the design, and in which the RF energy is conducted along wires or is

radiated, exclusive of the transmitter for which provisions are made under parts of

Chapter 7 of NTIA Manual other than part 7.9, and exclusive of ISM equipment. (NTIA)

right-hand (clockwise) polarized wave. An elliptically- or circularly-polarized wave, in

which the electric field vector, observed in any fixed plane, normal to the direction of

propagation—while looking in the direction of propagation—rotates with time in a right-

hand or clockwise direction. (RR)

safety service. Any radiocommunication service used permanently or temporarily for the

safeguarding of human life and property. (RR)

satellite. A body which revolves around another body of preponderant mass and which has a

motion primarily and permanently determined by the force of attraction of that other

body. (RR)

satellite emergency position-indicating radiobeacon. An earth station in the mobile-

satellite service the emissions of which are intended to facilitate search and rescue

operations. (RR)

satellite link. A radio link between a transmitting earth station and a receiving earth station

through one satellite. A satellite link comprises one up-link and one down-link. (RR)

satellite network. A satellite system or a part of a satellite system, consisting of only one

satellite and the cooperating earth stations. (RR)

satellite system. A space system using one or more artificial earth satellites. (RR)

secondary radar. A radiodetermination system based on the comparison of reference

signals with radio signals retransmitted from the position to be determined. (RR)

GL-23

semi-duplex operation. A method which is simplex operation at one end of the circuit and

duplex operation at the other.

ship earth station. A mobile earth station in the maritime mobile-satellite service located on

board ship. (RR)

ship movement service. A safety service in the maritime mobile service other than a port

operations service, between coast stations and ship stations, or between ship stations, in

which messages are restricted to those relating to the movement of ships. Messages

which are of a public correspondence nature shall be excluded from this service. (RR)

ship station. A mobile station in the maritime mobile service located on board a vessel

which is not permanently moored, other than a survival craft station. (RR)

ship's emergency transmitter. A ship's transmitter to be used exclusively on a distress

frequency for distress, urgency, or safety purposes. (RR)

Signal. The physical representation of information (IEEE Std.100-1992)

simplex operation. Operating method in which transmission is made possible alternately in

each direction of a telecommunication channel, for example, by means of manual

control.

(RR)

single-sideband emission. An amplitude modulated emission with one sideband only. (RR)

space operation service. A radiocommunication service concerned exclusively with the

operation of spacecraft, in particular space tracking, space telemetry and space

telecommand. These functions will normally be provided within the service in which the

space station is operating. This service may also include feeder links necessary for its

operation. (RR)

space radiocommunication. Any radiocommunication involving the use of one or more

space stations or the use of one or more reflecting satellites or other objects in space.

(RR)

space research service. A radiocommunication service in which spacecraft or other objects

in space are used for scientific or technological research purposes. (RR)

space station. A station located on an object which is beyond, is intended to go beyond, or

has been beyond, the major portion of the earth's atmosphere. (RR)

space system. Any group of cooperating earth stations and/or space stations employing

space radiocommunication for specific purposes. (RR)

space telecommand. The use of radiocommunication for the transmission of signals to a

space station to initiate, modify, or terminate functions of equipment on an associated

space object, including the space station. (RR)

GL-24

space telemetry. The use of telemetry for the transmission from a space station of results of

measurements made in a spacecraft, including those relating to the functioning of the

spacecraft. (RR)

space tracking. Determination of the orbit, velocity, or instantaneous position of an object

in space by means of radiodetermination, excluding primary radar, for the purpose of

following the movement of the object. (RR)

spacecraft. A man-made vehicle which is intended to go beyond the major portion of the

earth's atmosphere. (RR)

special service. A radiocommunication service, not otherwise defined in this section, carried

on exclusively for specific needs of general utility, and not open to public

correspondence. (RR)

spectrum-dependent systems. Those systems, subsystems, devices, and/or equipment that

depend on the use of the electromagnetic spectrum for the acquisition or acceptance,

processing, storage, display, analysis, protection, disposition, and transfer of information.

(4650.1)

spectrum management. The planning, coordinating, and managing of joint use of the

electromagnetic spectrum through operational, engineering, and administrative

procedures. The objective of spectrum management is to enable electronic systems to

perform their functions in the intended environment without causing or suffering

unacceptable interference. (4650.1)

spectrum supportability. The determination as to whether the electromagnetic spectrum

necessary to support the operation of a spectrum-dependent equipment or system during

its expected life cycle is, or will be, available (i.e., from system development through

developmental and operational testing, to actual operation in the electromagnetic

environment). The assessment of an equipment or system as having “spectrum

supportability” is based upon, at a minimum, receipt of equipment spectrum certification,

reasonable assurance of the availability of sufficient frequencies for operation, and

consideration of EMC. (4650.1)

spread spectrum. A modulation technique for multiple access, or for increasing immunity

to noise and interference. Spread spectrum systems makes use of a sequential noise-like

signal structure, e.g., pseudonoise (PN)) codes, to spread the normally narrowband

information over a relatively wide band of frequencies. The receiver correlates these

signals to retrieve the original information signal. (IEEE Std 100-1992)

spreading loss (wave propagation). The reduction in radiant-power surface density due to

spreading. (IEEE Std 100-1992)

GL-25

spurious emission. Emission on a frequency or frequencies which are outside the necessary

bandwidth and the level of which may be reduced without affecting the corresponding

transmission of information. Spurious emissions include harmonic emissions, parasitic

emissions, intermodulation products, and frequency conversion products, but exclude

out-of-band emissions. (RR)

standard frequency and time signal service. A radiocommunication service for scientific,

technical and other purposes, providing the transmission of specified frequencies, time

signals, or both, of stated high precision, intended for general reception. (RR)

standard frequency and time signal station. A station in the standard frequency and time

signal service. (RR)

standard frequency and time signal-satellite service A radiocommunication service using

space stations on earth satellites for the same purposes as those of the standard frequency

and time signal service. This service may also include feeder links necessary for its

operation. (RR)

station. One or more transmitters or receivers or a combination of transmitters and

receivers, including the accessory equipment, necessary at one location for carrying on a

radiocommunication service, or the radio astronomy service. Each station shall be

classified by the service in which it operates permanently or temporarily. (RR)

steerable satellite beam. A satellite antenna beam that can be re-pointed. (RR)

suppressed carrier single-sideband emission. A single-sideband emission in which the

carrier is virtually suppressed and not intended to be used for demodulation. (RR)

survival craft station. A mobile station in the maritime mobile service or the aeronautical

mobile service intended solely for survival purposes and located on any lifeboat, life-raft,

or other survival equipment. (RR)

telecommand, The use of telecommunication for the transmission of signals to initiate,

modify, or terminate functions of equipment at a distance. (RR)

telecommunication. Any transmission, emission or reception of signs, signals, writings,

images and sounds or intelligence of any nature by wire, radio, optical, or other

electromagnetic systems. (RR)

telegram. Written matter intended to be transmitted by telegraphy for delivery to the

addressee. This term also includes radio telegrams unless otherwise specified (CS). In

this definition the term telegraphy has the same general meaning as defined in the

Convention. (RR)

telegraphy. A form of telecommunication in which the transmitted information is intended

to be recorded on arrival as a graphic document; the transmitted information may

GL-26

sometimes be presented in an alternative form or may be stored for subsequent use (CS

1016). A graphic document records information in a permanent form and is capable of

being filed and consulted; it may take the form of written or printed matter or of a fixed

image. (RR)

telemetry. The use of telecommunication for automatically indicating or recording

measurements at a distance from the measuring instrument. (RR)

telephony. A form of telecommunication primarily intended for the exchange of

information in the form of speech (CS 1017). (RR)

television. A form of telecommunication for the transmission of transient images of fixed or

moving objects. (RR)

terrestrial radiocommunication. Any radiocommunication other than space

radiocommunication or radio astronomy. (RR)

terrestrial station. A station effecting terrestrial radiocommunication. (RR)

tropospheric scatter. The propagation of radio waves by scattering as a result of

irregularities or discontinuities in the physical properties of the troposphere. (RR)

unwanted emissions. Consist of spurious emissions and out-of-band emissions. (RR)

GL-27