FCC manages  spectrum use for nonfederal users, including commercial, private, and  state and local government users. Selected Manufacturers and Commercial Licensees Have Taken a Variety of Actions to Improve Receiver Performance

To improve receiver performance, manufacturers and commercial  licensees have developed voluntary standards that are used to design  and procure receiver equipment for some services. Voluntary Industry Standards

Some industry-led organizations have adopted voluntary standards for  receivers. For example, the National Institute of  Standards and Technology—in partnership with other industry  representatives, the public safety community, and other government  agencies—has a testing process for public-safety land mobile radios. The Federal Government Has Used Standards, Procurement, and Other Actions to Improve Receiver Performance

To improve receiver performance, federal spectrum users have mandated  use of industry standards for receivers, specified system requirements to  procure equipment, and negotiated with other spectrum users to resolve  interference concerns. NTIA has mandated the use of standards for many  federal spectrum users while FCC has not done so for nonfederal  spectrum users, but both spectrum management agencies have taken  actions to resolve specific cases of interference and conducted research  to improve receiver performance. FCC has not set mandatory receiver standards for nonfederal spectrum  users. Therefore, FCC has generally relied on the  marketplace to incentivize nonfederal licensees and manufacturers to  produce receivers that can reject unwanted signals and limit interference. These challenges include the lack of  coordination across industries when developing receiver standards, the  lack of incentives to improve receivers, and the difficulty accommodating  a changing spectrum environment. Lack of Coordination among Those Developing Standards

Standards are often developed for a single industry operating within a  defined area of spectrum, such as the cellular industry. As one industry  researcher explained, there are no incentives for manufacturers to build  more robust receivers, primarily because the manufacturers will not  receive the benefits. As FCC attempts to accommodate new services and users, the  Commission often alters how licensees can use spectrum bands. Moreover, several stakeholders  we interviewed also said that it would be difficult and could take  considerable time to upgrade or replace receivers and equipment  currently in use once deployed. Stakeholders and Reports Identified Standards, Interference Limits, and Other Options to Improve Receiver Performance

Given the challenges that exist to improving receiver performance,  stakeholders we interviewed identified options that could be taken or led  by FCC and NTIA, with the aim of increasing spectrum efficiency. In fact, many stakeholders we  interviewed indicated that each case of adjacent-band interference is  unique, so a one-size-fits-all solution is likely not desirable or possible. FCC, NTIA, and others have studied many of these options,  and at a conceptual level, the advantages and disadvantages are well  known. Therefore, the  practical effects of each option, that is, what would happen if the option is  implemented, are not well known. Additional Information on Spectrum Use

Many stakeholders we interviewed said that additional transparency and  sharing of information on spectrum use and system characteristics by  FCC and NTIA could help mitigate interference problems involving  receivers by facilitating greater understanding of the systems already in  place and thus the potential for interference to arise from the deployment  of a new system in adjacent spectrum. Several options  have not been implemented, such as safe harbor standards and  interference limits, and others, such as mandatory standards, have only  been implemented for certain federal users, and it is unclear how these  experiences would translate to nonfederal users. Recommendation for Executive Action

To improve receiver performance and spectrum efficiency, we  recommend that the Chairman of the Federal Communications  Commission consider collecting information on the practical effects of  various options to improve receiver performance, including consideration  of small-scale pilot tests of these options. In particular, the report provides  information on (1) actions taken by selected manufacturers and  commercial licensees to improve receiver performance; (2) actions taken  by the federal government to improve receiver performance; (3)  challenges, if any, to improving receiver performance; and (4) options  identified by stakeholders and reports to improve receiver performance. Scope and Methodology

To address the engagement’s objectives, we reviewed relevant statutes  and regulations, and Federal Communications Commission (FCC) and  National Telecommunications and Information Administration (NTIA)  documents related to spectrum management, interference, and  transmission systems, with a focus on receivers.
Why GAO Did This Study

The growth of commercial wirelessbroadband services and government missions, including public safety and defense, has increased demand for radio-frequency spectrum. FCC and NTIA attempt to meet this demand while protecting existing users from harmful interference that can arise as new services and users come on line. To manage harmful interference, FCC and NTIA have historically focused on transmitters—the equipment that emitssignals. But, receivers also play a role. Congress and others are considering if further action to improve receiver performance to reduce harmful interference could help enhance spectrum efficiency and meet the growing demand for spectrum.
The Middle Class Tax Relief and Job Creation Act of 2012 directed GAO to study spectrum efficiency and receiver performance; GAO studied four areas related to improving receiver performance, including (1) actions taken by manufacturers and commercial licensees, (2) actions taken by the federal government, (3) challenges, and (4) options identified by stakeholders. GAO reviewed federal regulations and reports prepared by FCC, NTIA, industry stakeholders, and other researchers, and interviewed spectrum users, industry associations, and other stakeholders.

What GAO Found

Manufacturers and commercial licensees have taken a variety of actions to improve receiver performance. For some services, industry associations-- comprised of manufacturers, commercial licensees, and others--have developed voluntary standards that are often used to design and procure receivers, such as those in cell phones and televisions, and to help improve receiver performance. Stakeholders also reported privately negotiating to resolve interference problems and sharing of information as having helped improve receiver performance.
The federal government has used standards and taken other actions to improve receiver performance. Some federal spectrum users, like the Coast Guard and Department of Transportation, have specified or mandated use of industry standards for receivers using certain agency spectrum-based services. The National Telecommunications and Information Administration (NTIA), which manages the federal government's use of spectrum, has also mandated receiver standards for many federal spectrum assignments, such as those for land mobile radios used by emergency responders and radar systems. The Federal Communications Commission (FCC), which manages commercial and other nonfederal spectrum use, believes it lacks general authority to impose receiver standards and rather relies on the marketplace to improve receiver performance. In specific cases, FCC has provided incentives for nonfederal spectrum users to improve receivers. Both NTIA and FCC have taken additional actions to improve receiver performance, like undertaking studies and hosting public workshops.
Although industry and government have taken actions, stakeholders identified three challenges to improving receiver performance:
Lack of coordination across industries when developing voluntary standards: Standards are often developed for a single industry and not coordinated with those using adjacent spectrum.
Lack of incentives for manufacturers or spectrum users to incur costs associated with using more robust receivers: The benefits of improved receiver performance, namely freed-up spectrum for new services and users, often accrue to others and not those incurring the costs to improve receivers.
Difficulty accommodating a changing spectrum environment: When spectrum is repurposed for a new use, upgrading or replacing receivers currently in use to mitigate interference can be difficult and take considerable time.
In addition to greater use of voluntary industry standards, stakeholders GAO interviewed identified several other options to improve receiver performance. For example, interference limits would explicitly set a level of interfering signals that a receiver must tolerate before a user could seek government action to resolve interference problems. Each option entails trade-offs, and many stakeholders noted that a one-size-fits-all solution is likely not desirable or possible. Further, some options, such as interference limits, have not been implemented, and others, such as mandatory standards, have only been implemented for a limited number of users, primarily federal users. Therefore, the practical effects of these options--that is, what would happen if these options were individually or collectively implemented--are not well known, particularly for nonfederal users.

What GAO Recommends

FCC should consider collecting information on the practical effects of options to improve receiver performance. FCC replied that it had initiated such a fact-gathering process; GAO believes FCC's process to date may not provide information on the practical effects of these options.