a

GAO

United States General Accounting Office

Report to Congressional Requesters

May 2004 SPECTRUM 

MANAGEMENT

Better Knowledge 

Needed to Take 

Advantage of 

Technologies That 

May Improve 

Spectrum Efficiency

GAO-04-666
www.gao.gov/cgi-bin/getrpt?GAO-04-666.

To view the full product, including the scope 

and methodology, click on the link above. 

For more information, contact Katherine V. 

Schinasi at (202) 512-4841 or 

schinasik@gao.gov. 

Highlights of GAO-04-666, a report to 

congressional requesters 

May 2004

SPECTRUM MANAGEMENT 

Better Knowledge Needed to Take 

Advantage of Technologies That May 

Improve Spectrum Efficiency 

The nine federal agencies that GAO reviewed—which are among the largest 

users and investors in technologies and systems impacting spectrum use—

have made some investments in technologies that provide improved 

spectrum efficiency. However, these investments have tended to occur when 

agencies needed to make greater use of available spectrum to meet a 

mission requirement—not by an underlying, systematic consideration of 

spectrum efficiency. For example, as a result of growing spectrum 

constraints, the Department of Defense (DOD), the Federal Aviation 

Administration, and the National Aeronautics and Space Administration 

began investing in technologies that would increase the throughput of 

information while using smaller segments of their available spectrum. 

However, agencies also consider other factors—including cost and technical 

and operational concerns—that may dissuade them from investing in 

spectrum efficient technologies. For example, DOD may need to use more 

spectrum to meet an operational requirement to field a jam-proof and 

accurate radar for military aircraft. 

The current structure and management of spectrum use in the United States 

does not encourage the development and use of some spectrum efficient 

technologies. Because the spectrum allocation framework largely 

compartmentalizes spectrum by types of services (such as aeronautical radio 

navigation) and users (federal, nonfederal, and shared), the capability of 

emerging technologies designed to use spectrum in different ways is often 

diminished. For example, software-defined cognitive radios—radios that 

adapt their use of the spectrum to the real-time conditions of their operating 

environments—could be used to sense unused frequencies, or “white 

spaces,” and automatically make use of those frequencies. It may also be 

possible to use software-defined cognitive radios to exploit “gray spaces” in 

the spectrum—areas where emissions exist yet could still accommodate 

additional users without creating a level of interference that is unacceptable 

to incumbent users—to increase spectrum efficiency. Currently, however, 

the spectrum allocation system may not provide the freedom needed for 

these technologies to operate across existing spectrum designations, and 

defining new rules requires knowledge about spectrum that spectrum 

leaders do not have. At the same time, there are few federal regulatory 

requirements and incentives to use spectrum more efficiently. While the 

National Telecommunications and Information Administration (NTIA) is 

responsible for managing the federal government’s use of spectrum and 

ensuring spectrum efficiency, NTIA primarily relies on individual agencies to 

ensure that the systems they develop are as spectrum efficient as possible. 

Agencies’ guidance and policies, however, do not require systematic 

consideration of spectrum efficiency in their acquisitions. The lack of 

economic consequence associated with the manner in which spectrum is 

used has also provided little incentive to agencies to pursue opportunities 

proactively to develop and use technologies that would improve spectrum 

efficiency governmentwide. 

Recent advances in technologies 

that rely on the use of the radiofrequency spectrum have turned 

science fiction of the past into 

reality. Cellular telephones, 

wireless computer networks, global 

positioning system receivers, and 

other spectrum-dependent 

technologies are quickly becoming 

as common to everyday life as 

radios and televisions. Further, 

these technologies have become 

critical to a variety of government 

missions, including homeland 

security and strategic warfare. 

However, with the increased 

demand, the radio-frequency 

spectrum—a resource that once 

seemed unlimited—has become 

crowded and, in the future, may no 

longer be able to accommodate all 

users’ needs. As a result, there has 

been a growing debate among 

spectrum policy leaders about how 

to use spectrum more efficiently. 

To help inform these debates, GAO 

was asked to look at agencies’ 

investments in spectrum efficient 

technologies and how the nation’s 

spectrum management system may 

affect the development and 

adoption of these technologies. 

GAO is making six 

recommendations intended to 

facilitate greater investment by 

federal agencies in spectrum 

efficient technologies. Overall, the 

agencies indicated their 

commitment to promoting greater 

flexibility and more efficient use of 

radio spectrum. 
Page i GAO-04-666 Spectrum Management 

Letter 1

Results in Brief 2

Background 4

Agencies’ Decisions to Invest in New Technologies Are Generally 

Driven by Factors Other Than Achieving Spectrum Efficiency 10

Federal Spectrum Management System May Limit the Development 

and Adoption of Spectrum Efficient Technologies 17

Conclusions 28

Recommendations for Executive Action 28

Agency Comments and Our Evaluation 29

Appendix I Comments from the Department of Commerce 32 

Appendix II Comments from the Federal Communications 

Commission 33 

Appendix III Comments from the Department of Homeland 

Security 36 

Tables 

Table 1: Five Steps Associated with the Command-and-Control 

Approach to Spectrum Management 6

Table 2: Descriptions and Key Examples of Existing or Emerging 

Technologies That Can Improve Spectrum Utilization 9

Table 3: Agency Research and Development Investments in 

Technologies That May Improve Spectrum Efficiency 12

Figure 

Figure 1: NTIA’s Spectrum Measurement Van 22

Contents 
Page ii GAO-04-666 Spectrum Management 

Abbreviations 

AGILE Advanced Generation of Interoperability for Law 

 Enforcement 

DARPA Defense Advanced Research Projects Agency 

DHS Department of Homeland Security 

DOJ Department of Justice 

FAA Federal Aviation Administration 

FCC Federal Communications Commission 

FCS Future Combat Systems 

GHz gigahertz 

IWN Integrated Wireless Network 

JTRS Joint Tactical Radio System 

KHz kilohertz 

NSF National Science Foundation 

NTIA National Telecommunications and Information 

 Administration 

NEXCOM Next Generation Air/Ground Communications 

OMB Office of Management and Budget 

TTNT Tactical Targeting Network Technology 

TSAT Transformational Satellite 

UWB ultra-wideband 

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Page 1 GAO-04-666 Spectrum Management 

May 28, 2004 

The Honorable Tom Davis 

Chairman, Committee on Government Reform 

House of Representatives 

The Honorable Adam Putnam 

Chairman, Subcommittee on Technology, Information 

 Policy, Intergovernmental Relations, and the Census 

Committee on Government Reform 

House of Representatives 

Over the past several decades, the development and use of 

telecommunications and information technology has expanded 

dramatically, greatly increasing the use of the radio-frequency spectrum. 

Cellular telephones, wireless computer networks, and global-positioningsystem receivers are quickly becoming as common to everyday life as 

radios and televisions. Wireless communications have become critical to 

private industry and a variety of government missions—ranging from 

scientific research and public safety to homeland security and strategic 

warfare. As a result, the radio-frequency spectrum, which once seemed 

unlimited, has become crowded and, in the future, may no longer be able 

to accommodate all users’ needs. 

Because of the growing demand for spectrum, there has been increased 

attention in spectrum management policy debates on ways to improve the 

efficient and effective use of spectrum. This has led to a growing interest 

in technologies that can provide more efficient use of spectrum. Therefore, 

you asked us to (1) determine whether federal agencies are investing in 

developing spectrum efficient technologies and the key factors they 

consider in making these investments and (2) determine the extent to 

which the nation’s system for managing government and private sector use 

of spectrum facilitates the development and adoption of these 

technologies. 

Our review focused on federal agencies that are among the largest users of 

technologies and systems impacting spectrum use—the Department of 

Defense (DOD), the Federal Aviation Administration (FAA) within the 

Department of Transportation, the Department of Homeland Security 

(DHS), the Department of Justice (DOJ), and the National Aeronautics and 

Space Administration (NASA)—as well as the National Science 

United States General Accounting Office 

Washington, DC 20548 
Page 2 GAO-04-666 Spectrum Management 

Foundation (NSF), which funds research on spectrum-related 

technologies. To determine whether agencies were investing in 

technologies that might improve spectrum efficiency, we reviewed agency 

budget and investment planning documents and sought additional 

information from agency officials on specific programs and projects. To 

assess the key factors that influenced agency investment decisions, we 

interviewed agency officials and reviewed various documents and studies. 

To determine the extent to which the nation’s spectrum management 

system facilitates the development and adoption of these technologies, we 

interviewed officials at the two agencies responsible for spectrum 

management in the United States—the Federal Communications 

Commission (FCC) and the Department of Commerce’s National 

Telecommunications and Information Administration (NTIA)—and 

reviewed these agencies’ spectrum management policies and procedures. 

We reviewed processes established by the federal spectrum management 

system and individual agencies for addressing new technologies. We also 

met with officials at the agencies we reviewed to discuss the challenges of 

developing and adopting new technologies under the current spectrum 

management system. In addition, we interviewed experts and reviewed 

studies from private sector organizations that are examining spectrum 

policies and technologies—including the Center for Strategic and 

International Studies and the National Academy of Sciences—and 

attended several private- and government-sponsored conferences and 

forums on national spectrum management issues and new spectrum 

technologies. 

We performed our work from June 2003 through May 2004 in accordance 

with generally accepted government auditing standards. 

The agencies that we reviewed have made some investments in 

technologies that provide improved spectrum efficiency. However, these 

investments have been primarily driven by the imperatives of their 

individual missions—not by an underlying, systematic consideration of 

spectrum efficiency. For example, as a result of growing spectrum 

constraints, DOD, FAA, and NASA began investing in technologies that 

would increase the throughput of information while using smaller 

segments of their available spectrum. These investments were needed to 

meet mission-specific requirements and goals, such as DOD’s need for 

enhanced communications capabilities to meet its goal of information 

superiority and network-centric war-fighting, and FAA’s need to meet 

growing demands for air traffic control communications. In addition to 

Results in Brief 
Page 3 GAO-04-666 Spectrum Management 

mission requirements, agencies consider other factors and tradeoffs—

including cost and technical and operational concerns when making 

investment decisions. However, some of these considerations may 

dissuade agencies from investing in spectrum efficient technologies. For 

example, to meet an operational requirement to field jam-proof and 

accurate radar for military aircraft, DOD may need to use more spectrum. 

The current structure and management of spectrum use in the United 

States may limit the development and use of some spectrum efficient 

technologies. Because the spectrum allocation structure largely 

compartmentalizes spectrum by types of services (such as aeronautical 

radio navigation) and users (federal, nonfederal, and shared), the 

capability of emerging technologies that are designed to use spectrum in 

different ways is often diminished. For example, technologies like 

software-defined cognitive radios can be adapted to operate in virtually 

any segment of spectrum and, in the future, may be able to adapt to realtime conditions and make use of underutilized spectrum in a given 

location and time. Currently the spectrum allocation system, however, 

may not provide the freedom needed for these technologies to operate 

across existing spectrum designations. Moreover, defining new rules to 

accommodate these emerging technologies requires knowledge about 

spectrum use that is not currently available. For example, NTIA and FCC 

do not have a sufficient understanding of the spectrum environment, 

including how and how much spectrum is used, and lack agreed-upon 

models to assess spectrum efficient technologies. At the same time, there 

are few federal regulatory requirements and incentives for agencies to use 

spectrum more efficiently. While NTIA is responsible for managing the 

federal government’s use of spectrum and ensuring spectrum efficiency,1

NTIA primarily relies on individual agencies to ensure that the systems 

they develop make as efficient use of the spectrum as possible. Agencies’ 

guidance and policies, however, do not require systematic consideration of 

spectrum efficiency in their acquisitions. The lack of economic 

consequence associated with the manner in which spectrum is used has 

also provided little incentive to agencies to pursue opportunities 

proactively to develop and use technologies that would improve spectrum 

efficiency governmentwide. 

 1

 FCC has authority over all nonfederal spectrum use, including the use of spectrum by 

state and local governments. 
Page 4 GAO-04-666 Spectrum Management 

We are making six recommendations to help facilitate greater 

consideration and investment by federal agencies in spectrum efficient 

technologies. Specifically, we are recommending that the NTIA 

Administrator and the FCC Chairman jointly take actions to build more 

flexibility into the spectrum allocation system where feasible and gain a 

better understanding of the current spectrum environment and spectrum 

efficient technologies to increase the use of these technologies. We are 

also recommending that the NTIA Administrator take actions to encourage 

agencies to use spectrum more efficiently. In commenting on the draft 

report, FCC supported our recommendations. The Department of 

Commerce also commented on the draft, though it did not specifically 

address our recommendations. 

The radio-frequency spectrum supports a vast array of government and 

commercial services, including radio and television broadcasts, personal 

communications services, satellite communications, wireless local area 

networks, public safety communications, air traffic control, scientific 

research, and radar-based weather forecasting. The radio spectrum spans 

a range of frequencies within the electromagnetic spectrum from about 3 

kilohertz (kHz) to 300 gigahertz (GHz), but most of its use is concentrated 

in the lowest 1 percent of these frequencies—sometimes referred to as the 

“beachfront property” of the radio spectrum.2

 Advances in technology have 

greatly expanded the usable portions of the radio-frequency spectrum and 

have led to more efficient means of using the available spectrum. 

Simultaneously, these advances have created opportunities to provide new 

spectrum-dependent services, which have led to even greater demand on 

the limited available spectrum.3

 2

 Radio waves are a form of electromagnetic energy, propagating through space at the 

speed of light. The number of waves that pass a given point per second defines the 

frequency of a radio wave in cycles per second, or hertz. Kilohertz (kHz), megahertz (MHz), 

and gigahertz (GHz) describe frequencies of thousands, millions, and billions of hertz, 

respectively. The radio spectrum above 100 MHz and below 3 GHz has propagation 

characteristics that are well suited for services such as mobile phones, radio and television 

broadcasting, some satellite communication systems, radars, and aeronautical telemetry 

systems. 

3

 Nearly 30 years ago, GAO reported that technology was creating demands for spectrum 

faster than it was creating methods to meet those demands. See U.S. General Accounting 

Office, Information on Management and Use of the Radio Frequency Spectrum—A LittleUnderstood Resource, B-159895 (Washington, D.C.: Sept. 13, 1974). 

Background 
Page 5 GAO-04-666 Spectrum Management 

The spectrum is managed to maximize the benefits derived from this 

limited resource, while mitigating interference among various users.4

Within the United States, the spectrum is managed jointly by the NTIA, 

within the Department of Commerce, and the FCC. NTIA is principally 

responsible for developing and articulating domestic and international 

telecommunications policy5

 and for managing the federal government’s 

use of the radio spectrum. FCC has authority over all nonfederal spectrum 

use, including the use of the spectrum by state and local governments. 

In managing the spectrum, FCC and NTIA have largely used a “commandand-control” approach, which dictates how each segment of the radio 

spectrum can be used and who can use it. This approach generally 

involves five steps: allocation, adoption of service rules or technical 

standards, certification, assignment, and enforcement. Table 1 describes 

each step. 

 4

 Interference occurs when two or more radio signals interact in a manner that disrupts or 

degrades the ability of these signals to convey information successfully to their intended 

receivers. However, the extent and impact of interference depends on the technologies 

used both to transmit and receive radio signals, and the types of services and applications 

supported. 

5

 Each country makes its own allocations of spectrum use; therefore, allocation decisions 

may differ in other regions of the world and in other countries. However, because radio 

wave propagation obeys the laws of physics and cannot be forced to respect national 

borders, spectrum management decisions (particularly allocation decisions) generally have 

been coordinated internationally. The International Telecommunication Union (ITU), a 

specialized agency of the United Nations, holds World Radiocommunication Conferences 

every 3 to 4 years to coordinate spectrum decisions and address other pressing 

international spectrum management issues. 
Page 6 GAO-04-666 Spectrum Management 

Table 1: Five Steps Associated with the Command-and-Control Approach to 

Spectrum Management 

Step Actions taken by FCC and NTIA 

Allocation Particular segments, or “bands,” of the radio spectrum are 

designated for specific types of services—for example 

aeronautical radio navigation—with bands of varying widths. 

Adoption of service rules 

or technical standards 

Rules and standards specify the required technical and 

operational characteristics of the radios (or other radiofrequency devices) that will use the allocated band, such as 

radiated power limits, channel bandwidth and location, levels 

of acceptable interference, and other service-specific or 

band-specific rules. 

Certification Major federal systems that directly use the radio-frequency 

spectrum must be certified by NTIA, as required by the Office 

of Management and Budget (OMB) Circular A-11, to be 

assigned a bandwidth. An agency first determines if the 

system it proposes to field is “major”—that is, the system 

could cause significant impact on the radio-frequency 

spectrum—then conducts the necessary technical studies of 

the proposed system, selects potential frequency bands, 

coordinates with other agencies involved, and prepares and 

files a certification application to NTIA for review. FCC 

similarly certifies nonfederal systems. 

Assignmenta Once service rules and technical standards have been 

established, portions of the allocated band are assigned—

typically, to individual users or service providers operating 

within a certain geographic area through a variety of 

mechanisms. 

Enforcement Spectrum monitoring, interference reporting, and other 

regulatory mechanisms are used to enforce allocations, 

technical standards and service rules, and unique 

geography-based assignments. 

Source: GAO. 

a

Not all spectrum use requires an assignment. For example, many familiar “unlicensed” wireless 

devices—such as cordless phones, baby monitors, garage door openers, and wireless Internet 

access devices—are allowed to operate within certain spectrum bands provided they do not cause 

harm to assigned users and accept any interference received. 

NTIA and FCC implement the command-and-control approach differently 

because of differences in their missions. For example, NTIA assigns 

spectrum resources through an administrative process that emphasizes 

interdepartmental advice and coordination among federal agencies, while 

FCC has used a number of administrative processes including comparative 

hearings and lotteries as well as its authority to assign spectrum through 
Page 7 GAO-04-666 Spectrum Management 

auctions.6 However, because so much of the spectrum is shared between 

federal and nonfederal users, FCC and NTIA must coordinate their 

management of spectrum.7

For many decades, command-and-control has been the most commonly 

used approach for managing the spectrum. However, as both the usage of 

and demand for spectrum have exploded over the past decade, the 

disadvantages of the command-and-control approach have become 

increasingly apparent. For example, in October 2001, the FCC Chairman 

noted that it is becoming difficult for government officials to determine 

the best use for spectrum and to repeatedly adjust allocations and 

assignments of spectrum to accommodate new spectrum needs and new 

services. The President has similarly noted that the existing legal and 

policy framework for spectrum management has not kept pace with the 

dramatic changes in technology and spectrum use and can discourage the 

introduction of new technologies. 

In June 2002, the FCC Chairman established a Spectrum Policy Task Force 

to help identify and evaluate changes in spectrum management policy and 

to provide specific recommendations to FCC for ways to evolve from the 

current command-and-control approach to a more integrated, marketoriented approach. In November 2002, the Task Force reported its findings 

and recommendations to FCC.8

 While noting that no single regulatory 

model should be applied to all spectrum, the Task Force recommended 

that FCC pursue a spectrum management policy that includes both 

exclusive spectrum usage rights granted through market-based 

mechanisms and creates open access to spectrum “commons,” with 

command-and-control regulation used in limited circumstances. In 

January 2003, we issued a report recommending a commission be 

established to conduct a comprehensive examination of current U.S. 

spectrum policy. 9

 In May 2003, the President signed an executive 

 6

 47 USC § 309(j). 

7

 For more information on how spectrum is managed, see U.S. General Accounting Office, 

Telecommunications: Better Coordination and Enhanced Accountability Needed to 

Improve Spectrum Management, GAO-02-906 (Washington, D.C.: Sept. 30, 2002). 

8

 Federal Communications Commission, Spectrum Policy Task Force Report; ET Docket 

No. 02-135 (Washington, D.C.: Nov. 2002). 

9

 U.S. General Accounting Office, Telecommunications: Comprehensive Review of U.S. 

Spectrum Management with Broad Stakeholder Involvement Is Needed, GAO-03-277

(Washington, D.C.: Jan. 31, 2003). 
Page 8 GAO-04-666 Spectrum Management 

memorandum establishing the federal government’s “Spectrum Policy 

Initiative” to develop recommendations for improving spectrum 

management policies and procedures for the federal government and to 

address state, local, and private spectrum use.10

Although work under the President’s initiative is ongoing, the initiative 

recognizes, along with the findings of the 2002 FCC Task Force, that 

existing and emerging technologies create the potential for future radios 

and other radio-frequency devices and systems to use spectrum more 

efficiently.11 Efficiency may be accomplished through improvements to a 

broad set of technologies and applications. Table 2 provides descriptions 

and key examples of such technologies and applications that can improve 

the utilization of spectrum. 

 10 The initiative consists of two courses of spectrum-related activity: (1) an interagency task 

force to focus on improving spectrum management policies and procedures to stimulate 

more efficient and beneficial use of government spectrum and (2) a series of public 

meetings that will assist the Department of Commerce in developing a detailed set of 

recommendations for improving policies and procedures for use of spectrum by state and 

local governments and the private sector, as well as the spectrum management process as a 

whole. 

11 In addition, the NSF is currently sponsoring a study at the National Academy of Sciences 

on wireless technology advances and associated implications for spectrum management 

policy. 
Page 9 GAO-04-666 Spectrum Management 

Table 2: Descriptions and Key Examples of Existing or Emerging Technologies That Can Improve Spectrum Utilization 

Technology Description Key examples 

Radio frequency 

component-level 

Encompasses a broad set of radio-frequency 

components—transmitters, receivers, and 

antennas (and their enabling technologies)—

that can improve spectrum utilization. 

• “Smart” antennas that can selectively amplify desired 

signals while canceling out competing signals. 

• Modulation and channel coding can also influence how 

much spectrum is needed to transfer encoded voice 

data. 

Other component-level Encompasses a broad set of other (non-radio 

frequency) radio components including digital 

processors and associated algorithms to 

compress data, and batteries for handheld 

devices. 

• More advanced algorithms to encode and digitally 

compress a human voice can greatly reduce the 

radio’s data transfer requirements. 

• Improving the efficiency of a handheld radio’s battery 

can allow it to accomplish more sophisticated data 

compression, modulation and coding, and thus 

indirectly, influence the radio’s ability to use spectrum 

more efficiently. 

Network-level Technologies and related network or 

spectrum management practices that can 

significantly improve information transfer and 

spectrum efficiency as well as mission 

effectiveness. 

• Improvements to an ad-hoc network’s routing 

strategies can enable more efficient use of available 

network resources, including spectrum resources. 

• Advanced quality of service algorithms may enable a 

diverse set of network users with very different 

requirements and mission-driven priorities, to operate 

on a single network and share the spectrum resources 

of the entire network; these algorithms can grant high 

priority to the rapid transmission of critical 

communications and lower priority to routine message 

traffic. 

Other enabling 

technologies 

Includes investments in various technologies 

that may yield improvements to spectrum 

utilization and efficiency. 

• Advancements in microelectronics and semiconductors 

have enabled greater processing power in smaller 

lighter weight packages. These advancements 

continue with the development of semiconductor 

technologies that may greatly improve upon the 

performance of today’s radio-frequency components. 

• Research directed toward improving models of the 

ionosphere can lead to more efficient use of some 

frequency bands. 

Off-loading technologies Technologies that are being developed, which 

would facilitate “off-loading”—that is, 

relocating certain communications 

requirements from highly congested radiofrequency spectrum to higher radio-frequency 

bands and non-radio-frequency portions of 

the electromagnetic spectrum. 

• Research is under way to further the use of lasers to 

communicate at very high data rates. 

Source: GAO. 

Many spectrum efficient technologies have both component-level and 

network-level attributes. For example, some “smart” antennas can 

pinpoint the source signal and selectively amplify it while canceling out 

competing signals. In addition, because smart antennas direct transmitted 
Page 10 GAO-04-666 Spectrum Management 

power toward desired receivers, the level of interference experienced by 

other spectrum users is reduced. This adaptive behavior may be controlled 

by local sensors but may also be cued by information provided through the 

radio’s network. Similarly, software-defined radios, unlike traditional 

radios, have operating parameters (such as the operational frequency and 

modulation type) that are determined by software, meaning they can be 

programmed to transmit and receive on many frequencies and to use any 

desired modulation or transmission format within the limits of their 

hardware designs; as with smart antennas, the programmed operating 

parameters of the radio may be controlled internally or may be cued 

through the radio’s network. 

FCC and NTIA are both charged with promoting the efficient and effective 

use of the radio spectrum. NTIA has told us that ensuring efficient use of 

the spectrum is a major NTIA goal reflected throughout most of its 

spectrum management processes, which include 

• setting standards for equipment that use the radio spectrum, 

• certifying that proposed new systems conform with existing spectrum 

allocations and associated standards, and 

• requiring justification of frequency assignment requests and continuous 

review of existing frequency assignments. 

Additionally, NTIA is responsible for conducting spectrum analyses and 

research to keep abreast of the latest spectrum efficient technologies that 

are appropriate for government use and for developing and adopting 

automated information systems that support the spectrum management 

processes and facilitate appropriate spectrum conservation measures. 

Federal agencies have made some investments in technologies that may 

provide improved spectrum efficiency. However, their decisions to invest 

in those technologies are primarily driven by their individual missions—

not by an underlying, systematic consideration of spectrum efficiency. 

Agencies generally do not identify spectrum efficiency as a distinct 

category of technology investment. Other considerations that influence 

agencies’ technology decisions include technical and operational concerns 

and costs that may make spectrum efficient technologies impracticable. 

Agencies’ Decisions 

to Invest in New 

Technologies Are 

Generally Driven by 

Factors Other Than 

Achieving Spectrum 

Efficiency 
Page 11 GAO-04-666 Spectrum Management 

Determining investments that may improve spectrum efficiency is difficult 

because agencies do not clearly identify spectrum-related investments in 

their budgets. However, using published budget and other information 

provided to us by each of the nine agencies, we identified projects that 

might result in improved spectrum efficiency and spoke with agency 

officials about their technology investments. Based on this review, we 

identified 335 fiscal year 2004 federally funded projects that potentially 

included funding for spectrum efficient technologies.12 Funding for these 

projects totaled approximately $1.8 billion.13 These investments cover a 

wide range of technologies that can affect spectrum use, including the 

compression of raw source data, advanced radios, and network 

improvements. The military services and Defense Advanced Research 

Projects Agency (DARPA) combined are by far the largest federal 

investors in new technologies that use the spectrum. In contrast, the 

Departments of Justice and Homeland Security have small research and 

development budgets and tend to rely on technologies that are 

commercially available. Table 3 provides the total fiscal-year-2004 funding 

identified for each agency’s projects related to spectrum efficiency and 

highlights major areas of investment. 

 12 Amounts included for NSF are based on funds provided grantees in 2003. 

13 We did not verify the reliability of the funding information, however, it comes from 

published agency budget documents and program officials. 

Agency Mission Is a Key 

Factor in Determining 

Investments in New 

Technologies 
Page 12 GAO-04-666 Spectrum Management 

Table 3: Agency Research and Development Investments in Technologies That May 

Improve Spectrum Efficiency 

(Dollars in millions) 

Agency 

Areas of major investment 

related to spectrum efficiency 

Total funding for 

fiscal year 2004 

DARPA Antenna technologies, laser 

communications, transistor 

technologies, and cognitive 

communications 

$339.7

U.S. Air Force Software defined radio/laser 

communications 

649.4

U.S. Army Software defined radio 381.9

U.S. Navy/Marine Corps Software defined radios 172.4

NASA Optical (laser) communications 41.8

DOJ 0a

DHS 0b

FAA Air traffic control communications 

and digital radar 

165.8

NSF Interference avoidance and 

measurement, networking, antenna 

technologies, data compression, 

error correction, and cognitive radio 

research 

14.8c

Source: GAO. 

Note: Investments include amounts invested in projects undertaken with a stated goal of improving 

radio-frequency spectrum and projects where spectrum efficiency is not a stated goal but a possible 

outcome (including enabling technologies like software defined radios). These investments also 

include projects to off-load/achieve communications in non-radio portions of the electromagnetic 

spectrum, for example, laser communications. Because of the difficulty identifying relevant projects 

and quantifying relevant investments in projects where spectrum efficiency may be only a small 

component, actual investment numbers may be higher or lower. 

a

DOJ focuses on the acquisition of commercial-off-the-shelf equipment. 

b

While DHS is not currently funding research and development into technologies to provide improved 

spectrum efficiency, it expects to in the future. 

c

NSF grants funded in fiscal year 2003. According to agency officials, NSF has recently initiated a 

number of spectrum efficiency projects, including a study of programmable wireless networking, on 

which it plans to allocate at least $8 million per year. 

Agency investments in technologies that provide greater spectrum 

efficiency have tended to occur when agencies need to make greater use 

of available spectrum to meet a mission requirement and the additional 

spectrum is not readily available, as is the case with DOD. Specifically, 

DOD systems are requiring greater bandwidth to transmit intelligence and 

surveillance information, facilitate enhanced communications capabilities, 
Page 13 GAO-04-666 Spectrum Management 

and conduct electronic warfare—which DOD considers essential to 

meeting its key strategic goal of information superiority. As a result, DOD 

has made significant investments in new systems that, in part, address 

problems related to insufficient spectrum, as the following examples 

illustrate: 

• Joint Tactical Radio System (JTRS): To address key 

communications shortfalls and significantly improve military 

capabilities, DOD has begun to make significant investments in 

software-defined radios, which offer the potential of more efficient 

spectrum use in the future without the need for expensive and complex 

hardware changes. In 1997, DOD initiated the JTRS program to develop 

and apply this technology and to bring together separate service-led 

programs into a joint software-defined radio development effort. JTRS 

radios are intended both to interoperate with existing radio systems 

and to provide military users with more flexible communications 

capabilities in the future. 

• Air Force’s Transformational Satellite (TSAT) Program: The Air 

Force is exploring new technologies that enable communications in 

higher radio-frequency bands, which are much less congested, and in 

non-radio-frequency portions of the electromagnetic spectrum. Nonradio-frequency technologies will enable next-generation military 

satellites to communicate at very high data rates using lasers. As a 

result, information can be transferred without relying on the radiofrequency spectrum. 

• DARPA’s Tactical Targeting Network Technology (TTNT) 

Program: TTNT program aims to demonstrate a high-capacity sensor 

data system that could enable networks of strike aircraft to accomplish 

their missions. In particular, certain missions require the rapid sharing 

of targeting sensor data among a large ad-hoc network of strike 

aircraft. Currently, the U.S. military’s airborne tactical data links 

cannot support a large network of aircraft simultaneously due to 

spectrum constraints. TTNT is expected to provide a data rate 10 to 25 

times higher than the current airborne tactical data link in an 

equivalent amount of spectrum. 

Other agencies have made some investments in spectrum efficient 

technologies, and like DOD, these investments were largely driven by 

agency mission, as in the following examples: 

• NASA’s Mars Laser Communications Demonstration Project:

NASA anticipates a significant increase in the near future in demand 
Page 14 GAO-04-666 Spectrum Management 

for long-haul communications services from deep space to Earth. As a 

result, it has undertaken the Mars Laser Communications 

Demonstration Project—a joint project with the Massachusetts 

Institute of Technology’s Lincoln Laboratory—to develop a laser-based 

communications system that would transfer information without 

relying on the radio-frequency spectrum. Such a system would facilitate 

bandwidth-hungry instruments, such as imaging systems and radar to 

be used in deep space exploration. 

• Federal Aviation Administration’s Next Generation Air/Ground 

Communications (NEXCOM) Initiative: In 1990, FAA began the 

NEXCOM initiative in response to growing demands for air-to-ground 

air traffic control communications. By replacing current analog radios 

with digital radios, the program is expected to achieve greater 

spectrum capacity using the same spectrum currently allocated for air 

traffic control communications. Each of NEXCOM’s 25 kHz channels 

will support four voice circuits, instead of the one circuit supported by 

the current system. 

• DOJ’s Integrated Wireless Network (IWN) System: While Justice 

is not investing directly in research and development into technologies 

to improve spectrum efficiency, it has undertaken a joint effort—the 

IWN system—with the Departments of Homeland Security and 

Treasury to provide improved interoperability of communications 

within the federal law-enforcement community. New equipment being 

acquired under the IWN system, such as new land mobile radios, will 

significantly increase spectrum efficiency. 

Besides mission objectives, several other factors, such as technical and 

operational considerations and cost-effectiveness, influence agencies’ 

technology investments. In considering these factors, agencies may 

determine that using more spectrum efficient technologies is impractical. 

If an agency developed a system solely to minimize spectrum usage or 

optimize spectrum efficiency, the system may also include other less 

desirable or unacceptable operational characteristics—that is, 

characteristics that are incompatible with accomplishing an agency 

mission. For example, the Army’s Future Combat Systems (FCS)14—the 

 14 FCS is an information network linking a suite of 18 new manned and unmanned ground 

vehicles, air vehicles, sensors, and munitions. 

Other Factors That 

Influence Agencies’ 

Investment Decisions 
Page 15 GAO-04-666 Spectrum Management 

centerpiece of the Army’s plan to transform to a lighter, more agile, and 

more capable force—will rely on superior information to see and hit the 

enemy first. Future Combat Systems’ capabilities depend, in part, on the 

ability of the Army’s network to collect, process, and deliver vast amounts 

of information such as imagery and communications that will require 

much higher spectrum usage. Operational considerations also can affect 

radar aboard military aircraft. Such radars must operate in unfriendly and 

stressed conditions, including exposure to enemy jamming capabilities 

and flight speeds of up to 1800 to 2000 kilometers per hour. Aircraft radars 

must also function while the aircraft is conducting evasive maneuvers to 

avoid threats such as enemy missiles. According to DOD officials, the 

bandwidth used by aircraft radars is directly related to the radar’s 

accuracy. As a result, limiting the radar’s bandwidth could result in the 

aircraft engaging a wrong target or other unwanted consequences. Also, 

some federal agencies that intend to operate spectrum-dependent systems 

outside of the United States may have to compromise the application of 

more efficient technologies in order to acquire spectrum access in other 

countries. For example, in developing communications and radio 

navigation systems for aircraft, FAA is largely limited to using globally 

allocated bands that are designated for aeronautical services. 

In addition, agencies need to make tradeoffs between spectrum efficiency 

and cost. For example, a new type of smart antenna, called an adaptive 

array, can extend the range of communications systems and minimize 

interference. Although more efficient in its use of spectrum, this new 

technology is generally more expensive than traditional antenna 

technology, and, as a result, these technologies may not be considered or 

developed unless justified by mission needs. Similarly, the Department of 

Justice’s Advanced Generation of Interoperability for Law Enforcement 

(AGILE) program is coordinating the efforts of federal, local, state, and 

regional public safety organizations to achieve interoperable 

communications. However, local, state, and regional organizations may 

lack funding to replace their legacy radio systems and radio infrastructure 

with the most efficient systems available. As a result, these interoperability 

and funding concerns may dictate what technologies can be selected for 

use in new federal systems and may limit the degree of spectrum 

efficiency achieved. 
Page 16 GAO-04-666 Spectrum Management 

To help manage their investment decisions, some agencies have 

established science and technology planning processes to identify longterm technological needs, establish research and technology priorities, 

and coordinate research activities. These processes enable policy makers 

and implementers to adjust the allocation of agency resources to meet 

changing requirements for fulfilling agency missions. However, the 

agencies’ science and technology planning processes that we reviewed do 

not specify spectrum efficient technologies as an investment area. For 

example, FAA’s research and development strategy does not focus 

specifically on achieving spectrum efficiency; rather, it emphasizes 

improving the overall efficiency of the nation’s air traffic control 

systems—which may require making better use of the spectrum. Similarly, 

the military services’ science and technology planning processes 

emphasize achieving overall operational efficiency and effectiveness, 

which may or may not result in improved spectrum efficiency. A DOD 

official within the Office of the Assistant Secretary of Defense for 

Networks and Information Integration acknowledged that spectrum 

efficiency does not receive the same level of attention as science and 

technology efforts to improve more conventional weapons systems’ 

performance requirements such as lethality and survivability. 

However, DOD has taken initial steps to consider spectrum efficiency by 

revising its policy and guidance on spectrum management. Specifically, 

DOD’s Electromagnetic Spectrum Management Strategic Plan—which was 

issued in December 2002 —has five core principles, including one that 

recognizes the need to invest in new spectrum efficient technologies. In 

addition, the strategic plan established a goal to improve spectrum 

utilization through technological innovation. As part of developing a 

strategy for DOD, the Defense Spectrum Office15 has begun to study 

emerging technologies and future war fighter requirements. In addition, 

DOD convened a group of technologists last year to discuss spectrum 

technologies and how to link them more directly to DOD’s science and 

technology planning process. Because these efforts are in their early 

stages, they have not yet resulted in policy changes or modifications to 

investment plans. Similarly, NASA is working on an electromagnetic 

spectrum management strategy, which is in the final stages of review 

before release. 

 15 The Defense Spectrum Office has the responsibility within DOD for supporting the 

Assistant Secretary of Defense for Networks and Information Integration in establishing 

national and international strategies for new technologies that may affect how spectrum is 

used, occupied, or managed by the department. 

Agencies’ Technology 

Planning Processes Do Not 

Identify Spectrum 

Efficiency as an 

Investment Area 
Page 17 GAO-04-666 Spectrum Management 

The current structure and management of spectrum in the United States—

allocating bands of spectrum to certain users for specific uses—may limit 

the development and adoption of some emerging technologies that 

promise improved spectrum efficiency. However, redefining this structure 

and management of spectrum to take full advantage of future 

opportunities to improve spectrum efficiency could be difficult due, in 

part, to the lack of flexibility in the spectrum allocation system, policy 

makers’ limited knowledge about spectrum use and new and emerging 

technologies, as well as a lack of agreed-upon models to assess these 

technologies. At the same time, there are few regulatory requirements and 

incentives to encourage agencies to develop and use spectrum more 

efficiently. The current federal regulatory framework and system 

certification process tend to focus only on major systems that directly use 

the radio spectrum and their compliance with existing standards to avoid 

interference—not on spectrum efficiency. A lack of incentives to achieve 

spectrum efficiency also limits agencies’ consideration of spectrum 

efficient technologies in the acquisition of systems. However, providing 

such incentives is challenging, in part, because financial considerations 

must be balanced with mission needs. 

To manage the use of the radio-frequency spectrum in the United States, 

FCC and NTIA allocated the spectrum into federal, nonfederal, and shared 

bands and designated specific bands for specific uses, such as broadcast 

radio and television. Historically, this structure has served a valuable 

function. In addition to seeking to avoid interference among users, the 

structure has enabled spectrum leaders to balance government and 

commercial interests, provide stability and design certainty for equipment 

manufacturers, and accommodate a certain level of increased demand by 

apportioning spectrum for future uses. However, the current allocation 

structure has proven effective largely because technologies operated 

within a fairly narrow range of spectrum. While emerging technologies 

that use wider segments of spectrum or move across segments of 

spectrum may be able to operate within current demarcations, greater 

efficiencies may be achievable if these technologies were allowed to 

operate in an environment that provides more operational freedom than 

the current structure. 

With nearly all of the spectrum allocated and access rights granted to 

users, such freedom tends to require increased “sharing” of the 

Federal Spectrum 

Management System 

May Limit the 

Development and 

Adoption of Spectrum 

Efficient Technologies 

Current Spectrum 

Structure and Management 

Could Constrain Efforts to 

Use Spectrum More 

Efficiently 
Page 18 GAO-04-666 Spectrum Management 

spectrum16—that is, allowing more than one user to transmit radio signals 

on the same frequency band.17 In working to increase spectrum sharing, 

spectrum leaders will need to carefully consider the impacts on incumbent 

users’ operations and define appropriate rules to mitigate those impacts. 

However, attaining agreement on such rules may be difficult and could 

result in operational constraints that reduce the promise of increased 

spectrum efficiency. For example, radios that are largely defined by their 

software components could provide greater efficiencies if software 

enabled them to operate in a shared environment—as DOD hopes to do 

with JTRS. Currently, DOD is developing 34 waveforms18 for use in JTRS 

radios. Of these, 33 waveforms are to be operationally identical to their 

respective, already fielded, traditional radio counterparts and, 

consequently, will be able to operate in the current spectrum structure. 

However, these waveforms will be no more efficient than their existing 

radio counterparts. While the remaining waveform promises to achieve 

greater spectrum efficiency in providing voice, video, and data services, it 

requires access to a wider swath of the spectrum, which JTRS program 

officials believe will challenge the current spectrum structure and 

certification process because it could impact other users’ operations. JTRS 

program officials stated that for the near term, some of the concerns 

associated with the new waveform could be addressed by using software 

“lockouts” to ensure that sensitive bands are protected. However, to 

achieve greater efficiency, JTRS program officials believe that spectrum 

sharing issues will need to be worked out, and spectrum policies and rules 

will need to be adjusted. 

 16 Greater freedom could also be achieved through “band clearing”—moving incumbent 

users to other parts of the spectrum. Because this reallocation could take significant time 

and funding to accomplish, band clearing is difficult to implement. 

17 In a shared spectrum allocation, “primary” users have priority over the use of a frequency 

and “secondary” users must defer to the primary user. Users may also be designated as “coprimary,” in which the first operator to obtain authority to use the spectrum has priority to 

use the frequency over another primary operator. 

18 A waveform is the representation of a signal that includes the frequency, modulation 

type, message format, and/or transmission system. In general usage, the term waveform 

refers to a known set of characteristics, for example, frequency bands (VHF, HF, UHF), 

modulation techniques (FM, AM), message standards, and transmission systems. In JTRS, 

the term waveform is used to describe the entire set of radio functions that occur from the 

user input to the radio-frequency output and vice versa. A JTRS waveform is implemented 

as a re-useable, portable, executable software application that is independent of the JTRS 

operating system, middleware, and hardware. 
Page 19 GAO-04-666 Spectrum Management 

As software-defined radios become more sophisticated, the challenge in 

employing them will become even greater. For example, software-defined 

cognitive radios—radios that adapt their use of the spectrum to the realtime conditions of their operating environments—could be used to sense 

unused frequencies, or “white spaces,” and automatically make use of 

those frequencies. According to FCC, many portions of the radio spectrum 

are not in use for significant periods of time and that tapping into these 

white spaces—both temporal and geographic—could significantly 

increase spectrum available for use.19 It may also be possible to use 

software-defined cognitive radios to exploit “gray spaces” in the 

spectrum—areas where emissions exist but that could accommodate 

additional users without raising the overall noise level in a band to a level 

unacceptable to incumbent users—to increase spectrum efficiency.20

However, employing the technologies needed to exploit these spaces 

could present significant problems of interference. Currently, FCC is 

exploring a new approach to cognitive radios and interference control and 

management21 based on the concept of measuring “interference 

temperature.”22 Under this concept, the interference temperature in a given 

band would be measured, and devices receiving these measurements 

would restrict their operations in order to maintain the interference 

temperature at or below a prescribed limit for that band. In the simplest 

case, the entire process would take place within an individual device, such 

as a software-defined cognitive radio capable of measuring the 

interference temperature at its location and making a decision to transmit 

 19 FCC Spectrum Policy Task Force Report; ET Docket No. 02-135 (Washington, D.C.: Nov. 

2002).

20 DOD’s DARPA has a major effort under way (the Next Generation Communications 

Program) to develop enabling technologies and system concepts to dynamically use the 

spectrum through real-time sensing of the spectrum environment and adjustment of radio 

operations to take advantage of white and gray space opportunities. Its goal is to increase 

spectrum access by a factor of 10. 

21 FCC Notice of Proposed Rulemaking and Order In the Matter of Facilitating 

Opportunities for Flexible, Efficient, and Reliable Spectrum Use Employing Cognitive 

Radio Technologies; FCC 03-322 (Dec. 30, 2003); FCC Notice of Inquiry and Notice of 

Proposed Rulemaking in the Matter of Establishment of an Interference Temperature 

Metric to Quantify and Manage Interference and to Expand Available Unlicensed Operation 

in Certain Fixed, Mobile and Satellite Frequency Bands; FCC 03-289 (Nov. 28, 2003). 

22 “Temperature” refers to a measure of the undesired radio-frequency power in a particular 

band and location. FCC’s Spectrum Policy Task Force developed the concept of an 

interference temperature to characterize and quantify undesired (interfering) transmitters’ 

contributions to radio-frequency energy at a receiver’s location. 
Page 20 GAO-04-666 Spectrum Management 

or not transmit based on this measurement plus its own contribution of 

radio-frequency energy. However, the interference temperature concept is 

controversial and in the view of many has yet to be successfully 

demonstrated in a practical context. NTIA believes that more study is 

needed to determine what might be the “correct” tool for quantitatively 

controlling interference between mobile and unlicensed transmitting 

devices that share spectrum with existing telecommunication facilities. 

The extent to which emerging and future technologies, such as those that 

would exploit white and gray spaces, could be utilized to increase 

spectrum efficiency is dependent on the degree of freedom these 

technologies would be provided to operate across the spectrum. While 

unconstrained operation may not be realistic—given the sensitivity of 

certain uses of spectrum—it may be possible to develop policy-based rules 

to maintain some constraints, such as blocking the use of certain 

frequency bands, while allowing greater freedom in other areas of 

spectrum. Defining such rules, however, requires a level of understanding 

of the spectrum environment—including how and how much spectrum is 

used—and spectrum efficient technologies that NTIA and FCC do not 

currently have. For example, in 2002, the FCC’s Spectrum Policy Task 

Force noted that in order to define rules for the implementation of the 

interference temperature concept, additional knowledge—including the 

need to acquire data on the current ambient noise levels for different 

frequency bands and geographic regions—would be required.23 To that 

end, the Task Force recommended a systematic study of the spectrum 

environment. 

Currently, NTIA has the capability to capture knowledge needed to better 

understand the radio spectrum environment through a radio spectrum 

measurement program, which it established in 1973 to assess whether 

spectrum is being used in accordance with applicable regulations and to 

provide information to prevent or resolve interference problems involving 

federal government systems.24 However, the measurement program is 

 23 Under the proposed approach, an interference temperature metric would establish 

maximum permissible levels of interference, thus characterizing the “worst case” 

environment in which a receiver would be expected to operate. Different threshold levels 

would then be set for each band, geographic region or service based on an understanding 

of the radio frequency environment. 

24 FCC and FAA also have spectrum-monitoring capabilities. 

Lack of Knowledge and 

Varying Perspectives about 

Spectrum May Further 

Constrain the Use of More 

Spectrum Efficient 

Technologies 
Page 21 GAO-04-666 Spectrum Management 

limited to measuring and recording radio signals between 10 kHz and 20 

GHz at selected sites through equipment housed in a single van (see 

fig. 1)25 and in portable suitcases. As such, the van has been used primarily 

to help reach consensus on difficult or unusual interference and spectrum 

sharing problems having a high national importance. For example, such 

measurements have assisted in reaching some consensus on the use of 

ultra-wideband (UWB) devices, expanded 5 GHz unlicensed device 

operation, and broadband over power lines. According to NTIA, all of 

these activities directly support the Administration’s goals related to 

facilitating emerging technologies. However, the last compliance-type 

measurements were conducted in the mid-1980s. According to NTIA, these 

measurements were discontinued because of a lack of resources and 

generally low benefits provided to national spectrum management. NTIA 

has also discontinued its broadband spectrum surveys—which covered 

the spectrum from about 100 MHz to 20 GHz.26 The last broadband survey 

measurements were made in the San Francisco area in 1995 with results 

reported in 1999. 

 25 In fiscal year 2002, NTIA received $2.1 million to replace the van. The replacement van 

was used for the first time in the summer of 2003. 

26 The term “broadband” used in this context refers to a survey of multiple radio frequency 

bands. The use of the term here does not refer to technologies that encompass all evolving 

high-speed digital technologies that provide consumers integrated access to voice, highspeed data, video-on-demand, and interactive delivery services. 
Page 22 GAO-04-666 Spectrum Management 

Figure 1: NTIA’s Spectrum Measurement Van 

In addition, NTIA lacks sufficient information to more accurately model 

and test the impact of emerging technologies to determine their likely 

operational characteristics. For example, NTIA must typically rely on 

federal agencies to provide information on the technical characteristics of 

their radio communication systems. According to NTIA officials, this 

information has been insufficient to perform detailed analyses of some 

technologies. Furthermore, since NTIA and FCC have different spectrum 

management responsibilities—federal and nonfederal, respectively—they 

have different perspectives on spectrum use. NTIA tends to focus on 

protecting the federal government’s use of the spectrum from harmful 

interference—especially in areas critical to national security and safety—

while FCC tends to focus on maximizing public access to and use of the 

spectrum. As a result, NTIA and FCC have different perspectives on the 

assumptions and operational scenarios that should be used to assess 

potential interference from new technologies. This divergence can lead to 

difficulties in establishing agreed-upon service rules and technical 

standards, resulting in delays in accommodating new technologies. 

Source: NTIA.
Page 23 GAO-04-666 Spectrum Management 

The effect of limited knowledge and varying perspectives on defining 

policy-based rules is demonstrated in the government’s recent efforts to 

accommodate commercially developed low-power UWB devices,27 which 

offer greater utilization of the spectrum in a shared environment. Potential 

uses include radar imaging of objects buried underground or behind walls 

and short-range, high-speed data transmissions. Because UWB devices 

transmit over large swaths of spectrum and emit into spectrum used by 

both federal and nonfederal users, NTIA and FCC have shared 

responsibilities in their use. However, there has been considerable debate 

over how much interference UWB devices would cause to other spectrum 

users—with particular concern for protecting the Global Positioning 

System and public safety systems. For example, NTIA was concerned that 

allowing UWB systems to emit intentionally into certain bands would 

cause potential interference to vital federal government services. To 

assess the potential impact of introducing UWB devices into the spectrum 

environment, NTIA had to make assumptions about the devices’ 

characteristics and simulate their transmissions because commercial UWB 

devices were not available for testing. 

In February 2002—after substantial debate among NTIA, FCC, and other 

interested parties—FCC established rules to allow the development and 

marketing of unlicensed, low-power UWB devices in a limited frequency 

range and with power limitations, based in large measure on standards 

recommended by NTIA.28 However, FCC has expressed its intent to revisit 

the adopted standards eventually because of its concern that the standards 

may be overly stringent—reflecting technical analyses of “worst case” 

scenarios, not real-life operating conditions—and could unnecessarily 

constrain development of UWB technology.29 Conversely, some federal 

agencies remain concerned that not enough is known about how UWB 

interacts with existing systems, including the aggregate effect of large 

numbers of UWB devices. According to FCC officials, UWB device 

manufacturers expressed concerns that their investments in components 

that comply with the adopted standards would be lost if a less restrictive 

order is adopted too soon. In February 2003, FCC made minor changes to 

 27 UWB devices employ very narrow or short duration pulses to create wideband 

transmissions. 

28 NTIA has also established similar rules governing federal use of low-power UWB devices. 

29 The lack of technologies capable of providing users with real-time knowledge of 

spectrum environments has required an approach to spectrum management based on 

worst-case assumptions to minimize interference. 
Page 24 GAO-04-666 Spectrum Management 

UWB regulations but opted not to make any significant changes to the 

existing UWB technical parameters, citing the lack of experience with 

UWB devices and concerns that any major changes to the rules for existing 

UWB product categories would be disruptive to current industry product 

development efforts. 

NTIA is responsible for promoting the efficient and effective use of 

spectrum that has been assigned to federal users. However, the current 

regulatory framework and system certification process for federal 

spectrum use tend to focus on compliance with existing standards to avoid 

interference, not on spectrum efficiency. Furthermore, agency regulations 

do not systematically require the consideration of spectrum efficiency in 

the development and acquisition of systems. 

While NTIA’s certification process helps avoid interference, it does not 

directly consider whether the fielded system would use too much 

spectrum or could incorporate other technologies to improve spectrum 

efficiency. In general, NTIA’s certification process focuses on maintaining 

the integrity of the current spectrum structure by ensuring that 

• fielded systems operate in a frequency band allocated for the type of 

service they provide, such as maritime mobile radio; 

• frequency assignments are available for systems to operate in their 

intended operational environment; and 

• the technical characteristics of fielded systems are compatible with the 

operation of other systems, that is, they will not significantly interfere 

with others. 

NTIA’s ability to influence spectrum use is also somewhat limited because 

it only receives and reviews spectrum certifications for “major” federal 

systems that directly use the radio-frequency spectrum—that is, systems 

that could have significant impact on other users of the radio spectrum—

with each agency determining which of its systems are major. In addition, 

systems that utilize spectrum, but are not direct transmitters or receivers 

of radio waves, such as network routing strategies, are not subject to the 

certification process and therefore not within NTIA’s influence. Finally, 

NTIA officials told us that in general, individual agencies have not 

identified and reported their long-term requirements for spectrum. These 

officials also indicated that telecommunication investments are not easily 

identifiable because agency budget submissions do not break out or 

otherwise provide the ability to readily identify investments for systems 

that require spectrum. Although agencies must obtain spectrum 

Federal Requirements to 

Invest in Spectrum 

Efficient Technologies Are 

Limited 
Page 25 GAO-04-666 Spectrum Management 

certification prior to submitting budget proposals to OMB for approval, as 

required by OMB Circular A-11, NTIA officials told us that OMB does not 

routinely receive this information from NTIA nor systematically review 

and coordinate intended spectrum use during its review of agency budget 

submissions. Because agency investment in radio spectrum dependent 

systems cannot be readily identified, NTIA officials also stated that NTIA 

has generally had to react to spectrum demands as they become apparent 

through the certification process as opposed to planning for future 

spectrum use. 

NTIA has generally relied on agencies to ensure that their systems are as 

spectrally efficient as possible.30 However, the acquisition guidance and 

policies of the agencies we reviewed do not require the systematic 

consideration of spectrum efficiency in the design and development of 

systems. Similar to NTIA’s certification process, these agencies’ internal 

certification procedures tend to focus on avoiding significant interference 

among systems. For example, FAA’s policy for the use of radio spectrum 

identifies spectrum efficiency as a broad objective, but its certification 

process focuses mainly on equipment characteristics and compliance with 

NTIA standards and national and international spectrum allocation rules. 

While DOD’s acquisition policies and procedures require system 

developers and acquirers to consider spectrum supportability, they do not 

specifically require consideration of spectrum efficiency. Ensuring 

spectrum supportability could ultimately result in some spectrum 

efficiencies. However, we have previously reported that DOD’s weapons 

programs often failed to obtain, consider, or act on spectrum 

supportability knowledge during the early stages of acquisition,31 as 

required by DOD policy. Several weaknesses underlie this failure, 

including program managers’ lack of awareness of spectrum certification 

 30 A few NTIA policies and technical standards do specifically require federal agencies to 

improve efficiency in a few portions of the spectrum. For example, in 1992, the Congress 

directed NTIA to adopt and implement a plan for federal agencies with existing mobile 

radio systems to use more spectrum efficient technologies. In response, NTIA required all 

federal agencies to upgrade their land-based mobile systems through narrowbanding, a 

process for reducing the amount of spectrum needed to transmit a voice signal, by 2008. 

NTIA also established a trunking program for land mobile systems in certain areas of the 

country. The trunking technique allows systems to share a common set of voice radio 

channels to conserve spectrum. For more information on NTIA’s efforts to promote 

efficiency through its narrowbanding and trunking policies for land mobile radios, see 

GAO-02-906. 

31 U.S. General Accounting Office, Spectrum Management in Defense Acquisitions, 

GAO-03-617R (Washington, D.C.: Apr. 30, 2003). 
Page 26 GAO-04-666 Spectrum Management 

requirements, out-of-date and unclear spectrum management publications, 

competing demands of program mangers, and a lack of effective 

enforcement mechanisms for existing spectrum certification 

requirements.32

The fact that spectrum is virtually cost free may influence whether 

agencies consider spectrum efficiency and invest in spectrum efficient 

technologies. Currently, agencies have little or no economic incentive to 

use the radio-frequency spectrum more efficiently because they pay only 

small administrative fees for its use. Once it is allocated and users gain 

access to the spectrum, there are generally no financial incentives for 

them to consider accommodating other users, or in many cases, even to 

move to more efficient technologies. Incentives—both governmentwide 

and agencywide—could theoretically go a long way in encouraging 

agencies to proactively develop and use spectrum efficient technologies. 

However, incentives may not be appropriate, desirable, or feasible in all 

circumstances. 

In the private sector, the goals of maximizing profits can be a strong 

incentive to increase efficiency and utilization of the spectrum. For 

example, firms offering cell phone service may use various technologies, 

such as modulation techniques, to increase the number of cell phone users 

in a particular band. While market-based incentives promote efficiency, 

this model is not easy to apply to the federal sector—largely because 

government agencies need to balance their missions of providing public 

benefit with achieving economies and the difficulty of finding ways to 

apply these economies. 

For more than a decade, NTIA and others have considered the use of 

market-based incentives to promote spectrum efficiency in the federal 

government. In its 1991 report U.S. Spectrum Management Policy: 

Agenda for the Future, NTIA suggests exploring with FCC various fee 

proposals that would invoke the forces of supply and demand to create 

market-based mechanisms for spectrum management. Following this 

report, NTIA imposed agency fees to cover its administrative costs, which 

amount to about $55 per assignment. In November 2002, FCC’s Spectrum 

Policy Task Force Report also discussed the use of fees to improve 

 32 In our April 30, 2003, report, we made several recommendations aimed at addressing 

these weaknesses. 

Creating Incentives to 

Encourage the 

Development and Use of 

Spectrum Efficient 

Technologies Is 

Challenging 
Page 27 GAO-04-666 Spectrum Management 

spectrum efficiency in the public sector where market forces may be 

inadequate to spur efficiency. In October 2003, the Center for Strategic and 

International Studies reported that market approaches such as licenses 

that can be traded or sold would allow the market to determine the most 

efficient use of the spectrum.33 The President’s Spectrum Policy Initiative, 

chaired by the Secretary of Commerce, is currently examining issues of 

spectrum efficiency. Adopting market-based incentives to encourage 

spectrum efficiency is not limited to the United States. To varying degrees, 

Australia, Canada, and the United Kingdom have put in place mechanisms 

to reflect the opportunity costs associated with government spectrum use. 

These mechanisms include auctions and incentive-based fees, more 

flexible licenses, and secondary markets. The three countries have 

reported more flexibility in reassigning and allocating spectrum to its most 

efficient use. 

However, creating viable economic incentives to achieve spectrum 

efficiency in the U.S. federal government may be difficult. As we have 

previously reported,34 NTIA could face several challenges if it decides to 

use such incentives. First, implementing a market-based approach may be 

difficult for some agency functions that are critical and unique, such as 

public safety and national defense. Second, incentives that would require 

greater flexibility among license holders of spectrum may ultimately result 

in problems of interference. Although flexibilities have resulted in 

improved spectrum efficiency in other countries, these flexibilities may 

not apply to the United States because of the unique and worldwide 

missions of the U.S. military and the divided structure and missions of the 

U.S. spectrum management system. Third, it is unclear whether licensees 

would have the right to buy and sell spectrum, and what rights would be 

conferred and under what circumstances rights would be granted. Finally, 

while it may be possible to impose fees on federal agencies’ use of 

assigned spectrum, it is far from obvious how such fees or other economic 

incentives could be applied to agencies’ opportunistic use of white and 

gray spaces in the spectrum—as would be the case with software-defined 

cognitive radios, which adapt their use of the spectrum in real time. In its 

2002 report, FCC also acknowledged that there are instances where 

 33 Center for Strategic and International Studies, Spectrum Management for the 21st 

Century: A Report of the CSIS Commission on Spectrum Management, (Washington, D.C.: 

Oct. 2003). 

34 GA0-03-277. 
Page 28 GAO-04-666 Spectrum Management 

regulation, as opposed to a market-oriented approach, is more 

appropriate. 

With the rapid advances in telecommunications technology and the 

increasing demand—both public and private—for radio-frequency 

spectrum, NTIA and FCC are faced with the daunting task of achieving 

greater spectrum efficiency while maintaining the level of services that 

users have come to expect. Further development and use of spectrum 

efficient technologies may provide an answer to this dilemma without 

negatively affecting the ability of agencies to carry out their missions; 

however, users have not actively pursued these technologies because 

there are few regulatory requirements or incentives to do so and because 

factors associated with the nation’s current spectrum management system 

may not encourage the use of these technologies. To ensure the most 

efficient use of spectrum, it will be necessary to rethink the current 

environment in which spectrum is managed, define requirements, and 

examine the requirements and incentives needed to encourage agencies to 

promote new and emerging technologies for achieving spectrum 

efficiency. Efforts currently under way at the national level, such as the 

President’s Spectrum Policy Initiative, provide an opportunity to establish 

appropriate policies and mechanisms, including incentives, to facilitate 

greater consideration of spectrum efficiency and create a more flexible, 

adaptable spectrum management environment that allows emerging 

technologies to fulfill their potential of spectrum efficiency. Without 

greater flexibility and incentives, efficiency may remain an unmet promise, 

and the growing demand for spectrum may soon threaten agencies’ ability 

to meet their missions. 

We are making six recommendations to help increase the development 

and adoption of spectrum efficient technologies. Specifically, we 

recommend that the NTIA Administrator and the FCC Chairman jointly 

• assess and determine the feasibility of redefining the spectrum 

allocation system to build in greater flexibility where appropriate to 

facilitate emerging technologies; 

• develop and implement plans to gain a more thorough and on-going 

understanding of the current spectrum environment; and 

• strengthen efforts to develop jointly accepted models and 

methodologies to assess the impact of new technologies on overall 

spectrum use and increase opportunities to permit testing of those 

technologies. 

Conclusions 

Recommendations for 

Executive Action 
Page 29 GAO-04-666 Spectrum Management 

To better ensure federal agencies consider and invest in spectrum efficient 

technologies, we further recommend that the NTIA Administrator 

• establish guidance for agencies to determine and report their future 

spectrum requirements; 

• strengthen NTIA’s spectrum certification process to more directly 

address spectrum efficiency; and 

• determine approaches, where appropriate, for providing incentives to 

agencies to use spectrum more efficiently and then pilot and measure 

the effectiveness of those approaches. 

We provided a draft of this report to the agencies that we reviewed. The 

Department of Commerce, FCC, and DHS provided written comments 

(reprinted as appendixes I, II, and III, respectively), and DOD, DOT, NASA, 

and NSF provided oral comments. DOJ did not have comments. 

FCC in commenting on the draft report supported our recommendations 

and indicated it would work with NTIA to incorporate the report’s findings 

and recommendations in future work. FCC also emphasized a number of 

actions it has taken to encourage and facilitate new technologies that 

might improve spectrum efficiency. The Department of Commerce did not 

comment on our recommendations but noted that NTIA and FCC “have 

met regularly to explore areas of common focus in spectrum 

management.” While we agree that meeting regularly is an important step 

toward building a more cohesive spectrum management process, it is not 

clear that these discussions have addressed or will address our 

recommendations to improve spectrum efficiency. Continued difficulty in 

reaching consensus between NTIA and FCC will hinder opportunities to 

accommodate new technologies and users and improve spectrum 

efficiency. 

Several of the agencies’ comments indicated their commitment to 

promoting greater flexibility and more efficient use of radio spectrum. 

Overall, the comments from agencies, other than NTIA and FCC, were 

generally technical in nature and were incorporated where appropriate. In 

addition, the agencies provided a few comments relating to our findings 

and recommendations. Most notably as follows: 

• NSF observed that future use of spectrum through software-defined 

cognitive radios could adversely affect the operation of sensitive radio 

telescopes that NSF supports. We agree that this is a valid concern 

because these systems are “passive”—or receive only—and their use of 

Agency Comments 

and Our Evaluation 
Page 30 GAO-04-666 Spectrum Management 

spectrum could go unnoticed. As noted in this report, when seeking to 

increase spectrum sharing, spectrum leaders will need to carefully 

consider incumbent users operations and define appropriate rules to 

obviate those impacts. 

• NSF, as well as DHS, also commented on our recommendations 

directed to the NTIA Administrator. Specifically, NSF noted that 

incorporating spectrum efficiency measures into the certification 

process of major systems could prove difficult and suggested either 

deleting or modifying the recommendation to focus on incentives. 

However, our recommendation does not call for the creation of 

measures but rather emphasizes the need for NTIA to focus on 

efficiency when considering certification. But in doing so, NTIA may 

determine that measures are an appropriate means to help increase 

spectrum efficiency and may be applicable in some cases. Further, we 

have recommended that NTIA take action to determine appropriate 

incentives for agencies to use spectrum more efficiently. Therefore, we 

did not modify our recommendations. Contrary to NSF, DHS stated 

that incentives do not apply to the government. While we recognized 

that incentives may not be applicable or desirable in all circumstances, 

we believe that there may be opportunities to use incentives to 

promote consideration of spectrum efficiency, and therefore 

recommended that such opportunities be explored. 

We are sending copies of this report to the Acting Assistant Secretary of 

Commerce for Communications and Information and Administrator of the 

NTIA, the Chairman of the Federal Communications Commission, the 

other agencies we reviewed, and interested congressional committees. We 

will also make copies available to others upon request. In addition, the 

report will be available at no charge on the GAO Web site at 

http://www.gao.gov. 
Page 31 GAO-04-666 Spectrum Management 

If you or your staffs have any questions about this report, please contact 

me at (202) 512-4841 or John Oppenheim at (202) 512-3111. Other 

individuals making key contributions to this report are Bruce Thomas, Jay 

Tallon, Gary Middleton, Karen Sloan, and Allison Bawden. 

Katherine V. Schinasi 

Managing Director 

Acquisition and Sourcing Management 
Appendix I: Comments from the Department 

of Commerce 

Page 32 GAO-04-666 Spectrum Management 

Appendix I: Comments from the Department 

of Commerce 
Appendix II: Comments from the Federal 

Communications Commission 

Page 33 GAO-04-666 Spectrum Management 

Appendix II: Comments from the Federal 

Communications Commission 
Appendix II: Comments from the Federal 

Communications Commission 

Page 34 GAO-04-666 Spectrum Management 
Appendix II: Comments from the Federal 

Communications Commission 

Page 35 GAO-04-666 Spectrum Management 
Appendix III: Comments from the Department 

of Homeland Security 

Page 36 GAO-04-666 Spectrum Management 

Appendix III: Comments from the 

Department of Homeland Security 
Appendix III: Comments from the Department 

of Homeland Security 

Page 37 GAO-04-666 Spectrum Management (120254) 
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