Scientists, Public Safety Agencies Concerned About 6 GHz Rule Changes

The National Academy of Sciences’ Committee on Radio Frequencies (CORF) and the National Public Safety Telecommunications Council are concerned about an FCC proposal that expands parts of the 6 GHz band where new very-low power (VLP) devices can operate (see 2310190054). Comments were posted on Wednesday in docket 18-295. The FCC has “recognized the public interest need to protect important radio astronomy and remote sensing observations at 6 GHz” and shouldn’t “undercut the protections already enacted in this proceeding,” CORF said. The 6650-6675.2 MHz band is important “for observations of methanol that play a critical role in research into star formation, astrochemistry, and precision astrometry,” the committee said. Frequencies between 6425 and 7250 MHz are used for passive microwave measurements, with 6425-7075 for ocean remote sensing, CORF said: “Observations at these frequencies are an essential component for both weather prediction and observing climate change.” NPSTC counseled against further liberalizing the rules for the 6 GHz band. “Public safety, critical infrastructure, commercial wireless and broadcast entities rely on this spectrum to support licensed microwave links for their respective operations,” the group said. It's clear from decisions made so far that the commission “has no intention of reversing course in this proceeding,” NPSTC said. If that’s the case “it is imperative that 6 GHz licensees have a viable mechanism to report and expeditiously resolve any 6 GHz harmful interference to critical microwave links that occurs.” The Bluetooth Special Interest Group (SIG) said studies show that unlicensed wideband VLP devices can operate at 14 dBm with a power spectral density of 1 dBm/MHz “without causing harmful interference into incumbent services, and that narrowband VLP devices will provide even greater margin.” The SIG has made a push for Bluetooth devices to be allowed to use 6 GHz spectrum (see [Ref2310270027]). “Bluetooth is an essential unlicensed technology that requires additional spectrum to support the volume growth of existing product categories and to support the technological expansion of important Bluetooth products,” the SIG said. The Wireless Innovation Forum told the FCC it’s “eager” to “support the development of geofencing systems,” one of the FCC’s proposals for protecting 6 GHz incumbents. The group said it could develop “specifications for data systems including any needed enhancements” and work on “propagation models to accommodate possible VLP mobility” and addressing “mobility in spectrum availability determinations.”