wireless lanThe FCC today took action aimed at maximizing unlicensed use of TV white spaces spectrum after the incentive auction of TV broadcast spectrum in the 600 MHz band is completed. The action took the form of two notices of proposed rulemaking in which the commission also noted the importance of protecting licensed uses of the spectrum from harmful interference from unlicensed devices.

One of the NPRMs proposes changes to Part 15 rules covering unlicensed devices. The other focuses on wireless microphones.

Details about the NPRMs won’t be known until they become publicly available, but FCC officials at today’s monthly FCC meeting offered some hints of what to expect.

“It’s time to kick the lawyers out of the room and let the engineers lead,” said FCC Commissioner Mignon Clyburne at today’s FCC meeting. Clyburne’s reference to lawyers pertains to comments filed with the FCC from parties that currently hold or would like to hold licenses in the 600 MHz band.

It’s not surprising that license holders would protest the idea of sharing spectrum with unlicensed users. But as several commissioners noted, unlicensed technologies such as Wi-Fi have become increasingly important to Internet users at the same time that the country seems to have exhausted all easy sources of new spectrum.

FCC Commissioner Jessica Rosenworcel said stakeholders need to “start by discarding the notion that Wi-Fi only comes at the expense” of licensed users.

Unlicensed Use of TV Spectrum
Broadband wireless equipment is already in use in the TV broadcast spectrum band in geographic areas where spectrum is not licensed to broadcasters or users of wireless microphones.  Advances in database technology have made it possible for equipment to know where spectrum is vacant and to automatically tune themselves to vacant channels. Efforts also are underway to use TV white spaces spectrum for a mobile or nomadic offering that would offer higher bandwidth than today’s Wi-Fi technology.

After the upcoming voluntary auction of TV broadcast spectrum, some 600 MHz spectrum will be licensed to wireless network operators to support mobile broadband service. As a result, the amount of spectrum available for unlicensed use is expected to decrease. Aiming to mitigate the impact of that decrease, the FCC earlier this year adopted a 600 MHz band plan post-auction that calls for allowing unlicensed users to operate in the guard bands, in the duplex gap and on Channel 37 where that channel is not in use by radio astronomers or for medical telemetry.

As adopted, the band plan also called for a portion of the duplex gap to be used by wireless microphones on a licensed basis. Based on comments made at today’s meeting it appears that the NPRM about wireless microphones also calls for opening up some other bands for use by microphones.

Commissioner Ajit Pai said today that the commission should have done more work on spectrum sharing before specifying the parts of the band plan that would be available for unlicensed use.

Rosenworcel said that as developers refine spectrum sharing solutions, there is an “opportunity here to pay dividends” beyond the 600 MHz band.

The FCC’s action comes just one week after the IEEE announced the availability of a new TV white spaces standard aimed at expanding the types of users that could be tracked by white spaces databases.