Electric utilities have asked a federal appeals court to vacate a Federal Communications Commission order that opened airwaves long held by energy and public safety assets to mass-market wireless devices and to force the FCC to put in place better safeguards before making those airwaves available for unlicensed use.
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US airwaves known as spectrum are the invisible infrastructure needed for wireless services. New rules adopted by the FCC in April make 1,200 megahertz of spectrum on the 6 GHz band available for unlicensed operations. That band houses private communications networks deployed by power plants, electric transmission lines, gas pipelines, control centers, substations and other energy assets for their mission-critical operations.
The FCC order was strongly opposed by power companies who asserted throughout the rulemaking proceeding that a flood of new unlicensed users on the 6 GHz band would create an "unreasonably high" potential for radio frequency interference that could disrupt communications systems that underpin the safety and reliability of the grid.
Utility trade groups, public safety officials, and other licensed users of the 6 GHz band argued in a joint legal brief recently filed with the US Court of Appeals for the District of Columbia Circuit that they did not oppose the deployment of new unlicensed devices "under appropriate conditions."
They contend, however, that the FCC unlawfully ignored evidence and committed blatant statistical errors to conclude that there was no "significant risk" of harmful interference.
Although major trade groups in the energy space, as well as the public safety industry, pressed the FCC to mandate a robust automated frequency coordination system for unlicensed operations at all power levels to mitigate interference to incumbent licensees, the agency mandated that only standard-power devices must transmit under the control of an AFC system, with no such requirement for indoor low-power operations.
The brief points out that the FCC order did not find that the requested safeguards would be infeasible or costly, "nor did it dispute that governing law prohibits opening the floodgates to hundreds of millions of unlicensed 6 GHz devices if there is a significant risk that at least some of them will interfere with some of [the] petitioners' licensed operations."
Petitioners in the consolidated case before the DC Circuit include the Edison Electric Institute, Utilities Technology Council, National Rural Electric Cooperative Association and American Public Power Association as well as AT&T, CenturyLink, the Association of Public-Safety Communications Officials International, and the National Association of Broadcasters (AT&T Services v. FCC, 20-1190).
They argue in the brief that the FCC assumed away less common but highly relevant real-world scenarios, such as situations where indoor devices may be used near windows or behind thin walls that do not absorb or weaken device signals and thus "will do little or nothing to protect nearby microwave links."
They further argue that the FCC's conclusions on interference "founder on a basic statistical fallacy" as the Monte Carlo methodology for risk analysis the agency relied on used far too few simulation iterations, failing to achieve the convergence needed for the curve produced to approach the real-life answer.
Specifically, the study quoted in the FCC order modeled 1,500 permutations of different interference-related variables. "But there is no reason to assume, and every reason to doubt, that these 1,500 snapshots in time are sufficient to permit statistically significant conclusions about the likelihood that some episodes of harmful interference will arise across the nation over a multi-year time span," the legal brief said.
Petitioners added in the brief that the FCC appears to have "plucked from thin air a somewhat lower power limit than the one" assumed in the study, but never identified any "reason to conclude that this arbitrary figure will protect the nation's microwave infrastructure and eliminate the 'worst case' scenarios that the FCC itself suggested 'would occur' at the somewhat higher power level."
The energy sector petitioners also asserted that the FCC arbitrarily ignored technical interference studies submitted by electric power entities, instead relying solely on the statistical analysis presented by proponents of the order.
Supported by the tech industry
Tech industry behemoths have contended that the order was necessary to aid 5G deployment and cure perceived Wi-Fi congestion as they looked to widely market a slew of new, inexpensively produced wireless products. The order effectively increased the amount of spectrum available for Wi-Fi by a factor of nearly five, creating greater capacity to support more devices and faster speeds.
A brief from the FCC is due to the court Feb. 16. Technology companies that intervened in the case in support of the order have until March 2 to file their own brief. Those intervenors include Apple, Broadcom, Cisco Systems, Google, Hewlett Packard Enterprise, Intel, Microsoft, Wi-Fi Alliance, and NCTA-The Internet & Television Association.
The energy groups and others will have an opportunity to respond to the FCC and tech sector's assessment of the lawsuit in a reply brief due April 2, with final briefs in the case due April 16. The DC Circuit has not yet set a date for oral argument.