FCC commissioners Tuesday voted to open the spectral white spaces between broadcast television channels for unlicensed use by devices utilizing geo-location solutions as the foundation for avoiding interference with incumbent users in the band.

Many white-spaces proponents argued that sensing technology had advanced enough that devices could be manufactured to determine whether a television station or a wireless microphone was being used on the frequency. However, FCC testing determined that sensing-only devices are not yet completely reliable at the moment.

“Our testing has shown that this [sensing-only] approach, right now, is not ready for prime time,” FCC Commissioner Michael Copps said during the FCC’s open meeting, which was webcast.

Instead, the commission approved devices using geo-location—a solution advocated by Motorola that incorporates GPS location technology with a database of broadcast TV stations’ coverage area to ensure that the device does not interfere with those channels—in the short term. While the FCC did not close the door to sensing-only devices, such devices would be subject to a “vigorous, public, proof-of-performance process,” FCC Chairman Kevin Martin during the meeting.

All FCC commissioners voted in favor of the item, although Commissioner Deborah Tate dissented in part. Tate expressed concern that the new rules do not include the legal responsibilities of those who create interference and noted that she believes at least part of the TV white spaces should be reserved for licensed use.

After the bulk of the spectrum in the last two FCC auctions—the AWS auction and the 700 MHz auction—was secured by incumbent wireless carriers, many industry observers expressed the belief that the commission needed to open the TV white spaces to unlicensed use to foster greater innovation and competition in the broadband wireless arena.

While the unlicensed band at 2.4 GHz has proven to be successful in the introduction of technologies such as Wi-Fi to the marketplace, the propagation characteristics at 2.4 GHz make it economically impractical to deploy wide-area networks using the technology except in dense urban environments. By using white-spaces spectrum below 700 MHz, “Wi-Fi on steroids” technologies can provide longer-range solutions—particularly in rural areas, where there is more white-spaces spectrum available for use.

“Our deregulatory order will allow the marketplace to produce new devices and new applications that we can’t even imagine today,” FCC Commissioner Robert McDowell said during the meeting. “Not only will the lives of millions of Americans be enriched by these new technologies, but I am confident that imaginative use of the TV white spaces could actually improve our safety, as well.”

Most public-safety officials have expressed skepticism that they would use unlicensed devices for their communications needs, particularly in the near term. However, many have viewed an unlicensed regime in the white spaces as an ideal test bed for new technologies that could lead to advancements in software-defined and cognitive radio that could prove valuable to the first-responder community.