FCC eyes midband spectrum between 3.7 and 24 GHz

The draft notice of inquiry on midband spectrum that FCC Chairman Ajit Pai circulated on Thursday asks a lot of detailed questions about three midrange bands, including whether a framework akin to the 3.5 GHz CBRS band would be appropriate for the 3.7-4.2 GHz band.

It also asks whether unlicensed use should be expanded within the 5.925-6.425 GHz band either under the FCC’s current rules governing U-NII devices or under other provisions, and seeks comment on the potential for more intensive fixed or flexible use of the 6.425-7.125 GHz band.

In addition to those specific spectrum bands, the FCC is asking about other potential opportunities for expanded flexible broadband use, on a licensed or unlicensed basis, in other bands within the 3.7 to 24 GHz range. It's also soliciting comments on whether auctions or incentive auctions like those that just closed for 600 MHz could be used to increase the availability of spectrum in the bands within the 3.7 to 24 GHz range.

The FCC will consider the midband spectrum item at its August 3 open meeting.

Separately, the commission is evaluating the feasibility of U-NII devices sharing the 5.85-5.925 GHz band with Dedicated Short-Range Communications (DSRC) systems operating under the Intelligent Transportation Service, a move that has agitated the automobile community, which is pursuing DSRC for vehicle safety.

At last Thursday’s open FCC meeting, the commission voted to expand the spectrum available for vehicular radars, including collision avoidance and adaptive cruise control, expanding the 76-77 GHz spectrum allocation to include the entire 76-81 GHz band and transitioning radar out of the 24 GHz band.

Commissioner Michael O’Rielly, who has been a big proponent of unleashing more upper 5 GHz spectrum for Wi-Fi along with former Commissioner Jessica Rosenworcel—who’s been nominated by President Donald Trump to return to the commission—said before the commission’s vote on Thursday that he had been more than hesitant to allocate such a large swath of spectrum to auto safety systems. He took the opportunity to note that it’s been almost two decades since the commission allocated 5.9 GHz spectrum for DSRC systems, and there’s still little to show for it.

However, he voted for the item because it consolidates all radars in one place in the 76-81 GHz band and the auto industry agreed to vacate other bands, such as the 16.2-17.7 GHz and 22-29 GHz band, over time, and it’s consistent with efforts to globally harmonize spectrum for vehicular radar operations in the 76-81 GHz band, he said.

Meanwhile, the FCC is sure to hear from myriad users and potential users of spectrum as part of the midband spectrum inquiry.

For example, the Fixed Wireless Communications Coalition (FWCC) filed a petition last October asking regulators to update the rules for the 3.7-4.2 GHz band so that more of that spectrum can be used for terrestrial applications. The satellite industry immediately registered its opposition, saying the FWCC filing just reiterates stale and unsupported allegations that were brought up in 1999 about the “supposed adverse effect of full-band, full-arc licensing of fixed-satellite satellite service (FSS) earth stations on the terrestrial fixed service (FS).”