Spectrum Management:

Further Consideration of Options to Improve Receiver Performance Needed

GAO-13-265: Published: Feb 22, 2013. Publicly Released: Feb 22, 2013.

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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.

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 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.

For more information, contact Mark Goldstein at (202) 512-2834 or goldsteinm@gao.gov.

Recommendation for Executive Action

  1. Status: Closed - Implemented

    Comments: The Federal Communications Commission (FCC), federal advisory councils, and others have recognized the growing impact of receivers on efficient spectrum use, and adjacent-band interference concerns may increase in the future as spectrum management agencies--including FCC--look to allocate additional spectrum for new services in an already crowded environment. In February 2013, we found that while FCC had studied options to improve receiver performance in the past, the Commission had not collected information on the practical effects of implementing various options, such as setting mandatory receiver standards or interference limits for spectrum users. Therefore, we recommended that FCC consider collecting information on the practical effects of various options to improve receiver performance, including consideration of small-scale pilot tests. In response to our recommendation, FCC issued a public notice in April 2013 to collect comments on two options to improve receiver performance--using an interference limits approach and collecting and publishing existing receiver standards--to understand the effects of these options. In this notice, FCC also invited comments on a white paper on interference limits produced by its Technological Advisory Council to determine what next steps may be appropriate for refining or testing this option, specifically whether FCC should consider pilot tests of this or other options to improve receiver performance and whether there are specific bands that would be appropriate for a pilot. Further, as part of a January 2014 workshop on proposed technical rules for the 3.5 GHz band, FCC sought comments on whether and how to use adjacent channel interference limits in the band. By considering and taking such first steps toward collecting information on the practical effects of options to improve receiver performance, FCC will be better able to make more informed spectrum-management decisions in the future to help prevent harmful interference and ensure the efficient use of spectrum.

    Recommendation: To improve receiver performance and spectrum efficiency, the Chairman of the Federal Communications Commission should consider collecting information on the practical effects of various options to improve receiver performance, including consideration of small-scale pilot tests of these options.

    Agency Affected: Federal Communications Commission

 

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