Luke Pensworth
The FCC has adopted final rules allowing use of white spaces in the United States (pdf final order). White spaces are unused broadcast television channels, between 54-698 MHz (TV Channels 2-51). Google believes they will pave the way for “Wi-Fi on steroids”.
It is the FCC’s first significant release of unlicensed spectrum in 25 years, said Chairman Julius Genachowski.
The decision paves the way for service providers and device makers to begin designing products that take advantage of the spectrum.
In a unanimous vote, the five-member FCC said the airwaves — unused channels between TV stations — will be used for mobile broadband services. Google and Microsoft are among companies that have advocated using whitespaces.
The FCC ditched the expensive “spectrum sensing” technology it initially required back in 2008, says Ars Technica. Google, Dell, and Public Knowledge worried that a requirement to include both the database check and spectrum-sensing hardware would make the new white space devices too costly and too difficult to build.
The FCC’s order, instead, would allow for two channels to be reserved for wireless microphones. New devices would have to meet technological standards set by the FCC that would prevent interference of broadcast shows. Each channel should accommodate 12-16 wireless mics, but large productions can petition the FCC for more spectrum in advance
U.S. Rep. Jay Inslee, D-Wash., sponsored the 2007 Wireless Innovation Act that helped sparked the white-spaces effort. He said in a statement, “This technology will benefit consumers in a variety of ways, not the least of which will be the high speed transmission of data between our energy using devices and our growing smart grid system that will make us far more efficient in our use of energy.”
Google, Microsoft and Dell have long lobbied to use white spaces, reports the Washington Post. Google envisions rural networks and remote meter reading. Microsoft has experimented with its own white-spaces network on its campus in Redmond. Dell believes white spaces will spawn innovations for the home.
FCC chairman Julius Genachowski predicted the white spaces would become a “powerful platform for innovation” and said the U.S. would be the first country to deploy the technology. He also cited an analyst’s estimate that the release could eventually add more than $7 billion to the U.S. economy annually.
Google hopes the FCC soon will name one or more administrators of the geolocation database, and establish the ground rules for its operation. Once the database is up and running, new white spaces devices and tools can begin to roll out to consumers.
White spaces aren’t likely to unset the balance of power anytime soon.
Mobile devices will be limited to 100 mW and fixed transceivers to 1 Watt (4 watts EIRP). But frequencies in the 500MHz range are likely to penetrate walls and concrete much better than 1900/2100 Mhz cellular or WiFi signals (at 2400 Mhz). They may also be used for Smart Meters and in-home communications.
WiFi, by contrast, can legally far exceed 4 watt EIRP in point to point applications. Unlicensed 2.4 and 5 GHz Wi-Fi act like pencil beams when using 18 to 30 db gain antennas, minimizing interference.
Antennas at 500 Mhz need to be much larger, so omnidirectional monopoles will likely be used. While WiFi uses 20 MHz channels, White Spaces would be restricted to 6 MHz channels, so speed may be in the 1 Mbps range.
Whether the FCC ruling will launch a new era in broadband remains to be seen.
TV white spaces availability can be found for any location in the US by downloading the company’s free iPhone application.
In white space tests by Spectrum Bridge, Airspan’s WiMax gear was frequency shifted to work in UHF TV channels and controlled by Spectrum Bridge’s database technology (white space primers).
Each Base Station is equipped with GPS and its location is sent back to centralized servers. Who will administer the database is still an open question. Google and Spectrum Bridge are among the companies that have applied for the job.
A new IEEE committee dubbed 802.11AF, has been formed to develop the standard. IEEE 802.22 was originally designed to “sniff” the air before transmitting, but the requirement was dropped because differentiating between licensed and unlicensed transmitters proved problematic.
