Business & GA, Commercial

Perspectives: FCC Interference Approach

By Anne Swanson | November 1, 2013

Since the Federal Communications Commission (FCC) released its “National Broadband Plan” in 2010, the agency has been aggressively trying to make more spectrum available for broadband. Besides exploring various allocation and auction mechanisms, the FCC recently released a study from its Technical Advisory Council (TAC) proposing to modify its approach to analyzing interference thresholds as one way of advancing broadband services. The TAC was chaired by the President’s nominee for FCC Chairman, who is expected to be confirmed this fall and likely favors its recommendations, so aviation equipment manufacturers will probably hear much more about them in coming months.

Since its inception, the FCC has always held newcomers responsible for interference they may cause to incumbent services. The TAC study suggests “turning the tables,” proposing an interference limits policy approach that would define the radio environment in which receivers operate. This probabilistic method known as “harm claim thresholds” would place limits on in-band and out-of-band interfering signals that must be exceeded before existing receivers can claim harmful interference.

Although the novel proposal is several administrative steps away from even being proposed as official rules, it drew a number of strong critiques when the FCC sought public comment. In joint comments, the GPS industry, including Garmin, noted that, as the study itself recognized, use of harm claim thresholds may not be appropriate, or may be particularly difficult to administer in certain circumstances, including when adjacent services are dissimilar, receivers are not controlled by license holders, and a service is not under FCC jurisdiction or involves safety-of-life systems like aviation. The GPS interests said the FCC must balance any benefits from this new approach against the cost of equipment replacement, R&D expenditures, and decreased functionality of existing devices. They emphasized that aviation equipment takes more than a decade to develop and certify and that, in the recent LightSquared case, FAA was never able to identify a mutually agreeable interference model that would provide confidence that LightSquared’s proposed service would not compromise aviation safety.

The Aeronautical Frequency Committee (AFC) also filed comments, noting that the proposal is not practical for the unique environment in which aviation services operate; it indicated the study’s proposed implementation process may actually create additional complexity, cost and uncertainty for various spectrum users not the manageable concept the study’s authors envisioned. AFC said any process should incorporate existing international standards, and a uniform “worst case value” should be applied to calculations for all locations. AFC also suggested that any implementation process should provide detailed frequency selection criteria and a notice period affording all interested parties, not just land mobile services, sufficient time to assess the new or revised interference limits; assign a minimum period of validity to any harm claim thresholds, so users will not face short-notice changes to previously agreed upon RF environments; and use a multi-stakeholder process to derive appropriate parameters for the thresholds, clarify areas of responsibility and investigation standards, and assign additional margins to account for unknown effects and protect existing services.

Rockwell Collins also expressed concern that the TAC study fails to consider the great costs, regulatory inefficiency, and potential risks to aviation safety that would result from new harm claim thresholds for GPS receivers. It noted harm claim thresholds are incompatible with existing receiver design and would impose unacceptable retrofitting costs on the installed GPS base. Expert domestic and international bodies already conduct a well-functioning standards process, which should continue for avionics.

Numerous other parties commented on the TAC study, but none specifically addressed aviation interests. These others presented mixed views on whether receiver performance standards in general are necessary and whether harm claim thresholds might improve receiver performance. Most parties opposed a one-size-fits-all solution and advocated the use of multi-stakeholder groups to investigate what thresholds might be appropriate.”For the TAC proposals to become codified rules, the FCC first will have to conduct a notice and comment rulemaking proceeding. That could be preceded by a more informal Notice of Inquiry proceeding to gather initial comments for drafting the proposed rules. Given the significant support the TAC study has within the FCC and broadband communities, aviation interests need to follow the FCC process.

Anne Swanson is a partner at Dow Lohnes PLLC, where she uses her administrative law expertise to help communications, equipment and navigation companies solve their regulatory problems. Her practice also focuses on complex spectrum issues and new technologies, such as unmanned vehicles and “smart transportation” systems.

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