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. 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. 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. 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. 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. 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 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. 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. 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. 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. 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. 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. 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.

Summary: 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. 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.