Spectrum Management: Better Knowledge Needed to Take Advantage of Technologies That May Improve Spectrum Efficiency
Published: 2004-05-28T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: 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.
section_title: What GAO Found
paragraphs: 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.

section_title: Letter
paragraphs: 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-positioning- system 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  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.
subsections: section_title: Background
paragraphs: 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. 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.
The spectrum is managed to maximize the benefits derived from this  limited resource, while mitigating interference among various users.  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 policy 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 “command- and-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.
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  auctions. However, because so much of the spectrum is shared between  federal and nonfederal users, FCC and NTIA must coordinate their  management of spectrum.
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, market- oriented approach. In November 2002, the Task Force reported its findings  and recommendations to FCC. 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.  In May 2003, the President signed an executive  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.
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. 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.
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  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.
section_title: Agencies’ Decisions to Invest in New Technologies Are Generally Driven by Factors Other Than Achieving Spectrum Efficiency
paragraphs: 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.
subsections: section_title: Agency Mission Is a Key Factor in Determining Investments in New Technologies
paragraphs: 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. Funding for these  projects totaled approximately $1.8 billion. 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.
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,  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. Non- radio-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 radio- frequency 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  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.
section_title: Other Factors That Influence Agencies’ Investment Decisions
paragraphs: 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)—the  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.
section_title: Agencies’ Technology Planning Processes Do Not Identify Spectrum Efficiency as an Investment Area
paragraphs: To help manage their investment decisions, some agencies have  established science and technology planning processes to identify long- term 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 Office 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.
section_title: Federal Spectrum Management System May Limit the Development and Adoption of Spectrum Efficient Technologies
paragraphs: 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.
subsections: section_title: Current Spectrum Structure and Management Could Constrain Efforts to Use Spectrum More Efficiently
paragraphs: 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  spectrum—that is, allowing more than one user to transmit radio signals  on the same frequency band. 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 waveforms 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.
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 real- time 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. 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.
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  management based on the concept of measuring “interference  temperature.” 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  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.
section_title: Lack of Knowledge and Varying Perspectives about Spectrum May Further Constrain the Use of More Spectrum Efficient Technologies
paragraphs: 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. 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. However, the measurement program is  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) 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. The last broadband survey  measurements were made in the San Francisco area in 1995 with results  reported in 1999.
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.
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, 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. 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. 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  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.
section_title: Federal Requirements to Invest in Spectrum Efficient Technologies Are Limited
paragraphs: 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  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. 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, as  required by DOD policy. Several weaknesses underlie this failure,  including program managers’ lack of awareness of spectrum certification  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.
section_title: Creating Incentives to Encourage the Development and Use of Spectrum Efficient Technologies Is Challenging
paragraphs: 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  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. 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, 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  regulation, as opposed to a market-oriented approach, is more  appropriate.
section_title: Conclusions
paragraphs: 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.
section_title: Recommendations for Executive Action
paragraphs: 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.
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    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.
section_title: Agency Comments and Our Evaluation
paragraphs: 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  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.
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.
section_title: Appendix I: Comments from the Department of Commerce
section_title: Appendix II: Comments from the Federal Communications Commission
section_title: Appendix III: Comments from the Department of Homeland Security