The IEEE, the organization that spearheaded spectrum sharing in the TV white spaces band, has begun work to enhance white spaces standards with the goal of enabling wireless network operators to share spectrum in the 3550 to 3650 MHz band with government users. In an interview Apurva Mody, chairman of the IEEE 802.22 Wireless Regional Area Networking Working Group, explained the concept of using “beacon” technology to keep track of where spectrum is available for commercial use.
Spectrum in the 3550 to 3650 MHz band is currently used by the U.S. Department of Defense for ship-mounted radar and for fixed satellite stations, Mody explained. In December, the FCC proposed allowing mobile network operators to use that spectrum in places where and at times when it is not used by the DOD – a move that was spurred by the success of using database technology to keep track of where TV spectrum is not in use and making that spectrum available for broadband wireless use.
“When you go to 3550 to 3650 MHz, this model may not work,” Mody said. The reason is that the radar-equipped ships come and go from one port to another – and it would be difficult for a database to keep up with those changes.
As an alternative, the IEEE is exploring the use of wireless beacons capable of receiving transmissions from the ships. Commercial users of the spectrum would receive that beacon and would use the 3550-3650 MHz spectrum only when it was not in use by nearby ships, thereby avoiding potential interference issues.
The IEEE aims to add standards for using beaconing to manage spectrum between 2 GHz and 4 GHz to the 802.22.1-2010 standard.
When the FCC proposed shared use of the 3550-3650 GHz band between government and commercial users, the commission recommended that mobile operators use it to support small cells, which have less range and transmit at lower power levels than traditional macrocells. The WhiteSpace Alliance has argued that with the appropriate technology, the spectrum band could support macrocells without interfering with government users and that there is no advantage to limiting the spectrum’s use to small cells.
Mody said the FCC has not yet made a recommendation on whether spectrum in the 3550 -3650 band would be made available to commercial users on an unlicensed basis or whether it would be auctioned to commercial users. A third option he said would be a “licensed light” approach that would enable commercial users to pay a relatively low annual fee for using the spectrum, which would be shared with other commercial users paying the fee (as well as with the government users).