Federated Wireless has been applying what it learned in the Citizens Broadband Radio Service (CBRS) to the 6 GHz band, where it has created new functionality to enable spectrum sharing.
The Federal Communications Commission (FCC) could make a decision about the 6 GHz band as early as April. The FCC issued a Notice of Proposed Rulemaking (NPRM) for the 6 GHz band in December 2018, setting in motion a plan to make 1,200 MHz of spectrum in the band for unlicensed use.
The 6 GHz band currently is used by licensees to provide microwave links for utilities, public safety, transportation and other uses. Federated Wireless’ new automated frequency controller (AFC) would be used to protect those incumbents while allowing for new users in the spectrum.
Federated is trying to replicate the process it went through in CBRS, where it’s now a Spectrum Access System (SAS) administrator, enabling a complex sharing system in the 3.5 GHz band. Its work in the 6 GHz band appears to take a lighter approach, however.
It’s working with equipment vendors and prospective operators so when the 6 GHz spectrum truly becomes available, it’s already done the work ahead of time and it’s a matter of crossing the “t's” and dotting the “i’s.
“We just want to get the process going so that we get the kinks out and can get this spectrum commercialized for new users as soon as possible,” Jennifer McCarthy, vice president of Legal Advocacy at Federated Wireless, told Fierce. Its AFC has been in the works for more than a year and it’s been refined with the help of the Wi-Fi, OEM and other affected communities, she said.
“We think we’ve got a pretty good sense of what people need and would like to see and commercialization could happen definitely by early 2021 and maybe even this calendar year,” she said.
One bone of contention in the FCC’s proceeding is whether or not low power indoor devices need a fail-safe mechanism like being connected to an AFC or if their low power use is sufficiently low that the risk of impacting an incumbent is little to none.
The Wi-Fi community argues that low power indoor operation poses very little risk, if any, and they have argued that there are ways to ensure devices stay indoors with techniques like no weather-proofing. But incumbents are inclined to prefer a fail-safe mechanism and the use of an AFC, which adds to the cost of devices.
Federated Wireless did an analysis in San Francisco, New York and Dallas for a variety of parameters. “We found that there were a couple of channels where even a low power indoor device had the potential to impact an incumbent and therefore … our AFC would have blocked a particular channel for that access point,” she said.
The Wi-Fi community doesn’t like that analysis because it doesn’t take into account things like the device’s activity level, such as whether it’s operating at full power all the time or only a very small portion of the time, but that wasn’t the nature of the study. “Our point to the FCC has always been, if you want to use the AFC to mitigate or correct for interference should it occur, the only way we can do that is if we’re in communication with the devices.”
Whichever way the FCC decides to go, Federated is demonstrating that it's ready to step up to the plate.
“Development of an AFC to enable unlicensed use of the 6 GHz band has been something of a moving target for the wireless industry, with some saying it is technically too difficult to develop and deliver at scale, and others seeing it as necessary to protect incumbent users,” said Monica Paolini, principal, Senza Fili, in a statement. “The Federated Wireless Spectrum Controller shows how an AFC can make spectrum sharing more efficient and foster adoption of Wi-Fi 6 and 5G in the 6 GHz band.”