The FCC is considering putting new restrictions on wireless use of C-Band spectrum, including a nationwide power reduction, as the Biden Administration works on how best to free up that spectrum for 5G without risking interference to critical aviation communications.
Wireless deployments in the band were delayed from fall given concerns by the Federal Aviation Administration, but are now scheduled to launch January 5, 2022.
That is according to FCC chair Jessica Rosenworcel in written answers to questions posed by Senate Commerce chair Maria Cantwell (D-Wash.) in advance of her confirmation to a new, five-year, term.
Also: Aviation Groups Warn of Serious Impacts From C-Band 5G Rollouts
According to a copy of those answers, Rosenworcel said that information it received* after adopting the framework for C-Band spectrum sharing suggested that the presence of C-Band operations could cause some erroneous altimeter readings.
Given that new info, she told Cantwell, the FCC is taking the report "very seriously," serious enough to open a proceeding to review the findings and whether any changes need to be made to the C-Band rules.
But she also said that, "out of an abundance of caution," the FCC, as part of ongoing discussions with the FAA, is considering a number of potential new interference mitigation strategies, including creating exclusion zones around airports and helipads, reducing power nationwide, and limiting "skyward" transmissions.
Last month, AT&T and Verizon, the biggest winners in the C-Band auction, said they would delay until January their use of the spectrum for which they paid billions of dollars at auction. That decision came after the FAA expressed its continuing interference concerns about C-Band to The Wall Street Journal and put out a bulletin advising pilots, aircraft owners, manufacturers and others on the potential impact of 5G flexible use operations in the C-Band on radio altimeters (RAs), which gauge how close a plane is to terrain.
But while the companies agreed to reduce 5G power levels, the coalition said those mitigation efforts were "inadequate and far too narrow." The coalition pitched the FCC on its own counter-proposal that "provides additional safeguards in, around, and on the approach to airports and heliports," one of those mitigation strategies the FCC is considering.
The FCC voted in 2020 to free up 300 MHz of C-Band (3.7-4.2 GHz) satellite spectrum for terrestrial 5G broadband, 280 of that to be auctioned and 20 MHz to be used as a guard band between wireless users and the incumbent satellite operators that are being relocated to the remaining upper 200 MHz to continue to deliver network programming to broadcasters and cable operators (and other) clients, and to relay video from the field to the studio.
*A report submitted by Radio Technical Commission for Aeronautics (RTCA) titled "Assessment of C-Band Mobile Telecommunications Interference Impact on Low Range Radar Altimeter Operations." ■
