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. Agencies’ Decisions to Invest in New Technologies Are Generally Driven by Factors Other Than Achieving Spectrum Efficiency

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. Other considerations that influence  agencies’ technology decisions include technical and operational concerns  and costs that may make spectrum efficient technologies impracticable. 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. As a  result, information can be transferred without relying on the radio- frequency spectrum. Operational considerations also can affect  radar aboard military aircraft. Federal Spectrum Management System May Limit the Development and Adoption of Spectrum Efficient Technologies

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. At the same time, there are few regulatory requirements and  incentives to encourage agencies to develop and use spectrum more  efficiently. Current Spectrum Structure and Management Could Constrain Efforts to Use Spectrum More Efficiently

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. 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 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. Lack of Knowledge and Varying Perspectives about Spectrum May Further Constrain the Use of More Spectrum Efficient Technologies

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. Federal Requirements to Invest in Spectrum Efficient Technologies Are Limited

NTIA is responsible for promoting the efficient and effective use of  spectrum that has been assigned to federal users. 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. Ensuring  spectrum supportability could ultimately result in some spectrum  efficiencies. 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. DOJ did not have comments.
Why GAO Did This Study

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.

What GAO Found

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.