IEEE sets standard for using ‘white space’ spectrum
SAN FRANCISCO — A just-published standard for using the “white spaces” between TV channels could offer as much as 22 Megabits per second over distances as great as 100 kilometers.

The Institute of Electrical and Electronics Engineers announced Wednesday that it has published the IEEE 802.22 standard, which defines the unlicensed use of frequencies between TV channels in the VHF and UHF bands. The IEEE 802.22 Working Group began its standards effort after the U.S. Federal Communications Commission started exploring the use of these frequencies by unlicensed devices. But the group said its standard could be used around the world, especially in rural areas and developing countries where there tend to be more vacant TV channels.

However, it isn’t clear who would take advantage of it. Iain Grant, managing director of SeaBoard Group, a Montreal-based telecommunications consultancy,  said the potential is there but there are obstacles to overcome. The white space bandwidth only offers 6 MHz channels, he said in an email. By comparison, Wi-Fi has channel widths of 20 Mhz and 40 Mzh. If a person is the only user on the network they might get 22 Mbps, but if there’s a few hundred users the speed might drop to 1 Mbps, he wrote.
Using the spectrum in a city is “probably more interesting,” he added, in part because the lower frequencies in this space will be better at penetrating basements and car parks.
EDITOR’S NOTE: After a request for comment, on Friday Industry Canada said it will soon issue a consultation paper on the potential use of TV white space. “Industry Canada has been closely following developments in the U.S. and Europe regarding the potential use of television white space spectrum to help meet the growing demand for spectrum,” the department said in an email. “We have already recieved a number of queries on this subject.”

Microsoft, Google and other big technology players strongly pushed for use of the white spaces in the U.S., going up against strong opposition by TV broadcasters who said unlicensed devices in those bands would interfere with their signals. IEEE 802.22 will not interfere with TV broadcasts, because it incorporates several features to prevent interference, including the use of databases of incumbent spectrum users, the IEEE said in a press release.

By using long-reach frequencies like those that transmit TV across metropolitan areas through walls, IEEE 802.22 could allow service providers to deliver mobile data services with fewer transmitters than ordinary cellular systems. This makes the standard promising for areas that are unserved or underserved, the IEEE said. As with Wi-Fi, use of white spaces won’t require anyone to pay a licensing fee.

The FCC approved the use of unlicensed gear in the white spaces in 2008, and last September it eased the regulations on these uses by removing the need for “spectrum sensing” technology. Devices will still need to have access to databases of what frequencies are being used nearby and be equipped with cognitive radio technology so they can change frequencies when necessary. The IEEE standard incorporates those features.

Consumers have just begun to receive Internet access over white-spaces spectrum, but over the next few years, the technology may be used widely for government applications, consumer services and backhaul from Wi-Fi networks, said Farpoint Group analyst Craig Mathias. TV uses channels in the same general band all over the world, and many countries have adopted white-spaces rules, so there may eventually be a global market for devices that use the technology, he said. High-volume production tends to bring low prices for equipment.

However, white spaces will never be used as widely as Wi-Fi or cellular, Mathias said. He expects its use to be focused on rural and underserved areas.

Even with its long range, the technology might be hard for service providers to use, said Gartner analyst Ken Dulaney.

“If this applies to rural areas, which I think is a target, you have problems with low density and thus have to price it high or lose money,” he said.

(With files by Howard Solomon, Network World Canada)