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Tom Simonite

A View from Tom Simonite

Long Range Wi-Fi Edges Nearer With FCC Decision

Wireless gadgets that weave signals between TV stations are a step closer.

  • September 23, 2010

A new class of devices able to create Wi-Fi-like connections that span miles rather than meters just jumped significantly closer to market. The Federal Communications Commission (FCC) has made a crucial decision on the rules that will regulate such devices, which will use the “white spaces” between TV channels that were freed up by the analog switch off.

Although the FCC voted in November 2008 to open up these white spaces, the exact rules governing how they could be used were not decided. Companies of all sizes, ranging from Google to startups, with plans for gadgets and services using white spaces have been waiting since then. Some have spent money lobbying for rules favorable to rapid development of a whole new sector.

A key concern was whether the FCC would stick with a previous suggestion that white spaces devices must constantly listen for broadcasts from TV stations and wireless microphones to ensure they wouldn’t cause interference. Today the commission decided that this isn’t necessary. Instead, the rules will require devices to be capable of knowing their location and using an online database to find out which channels are active in their area.

“The ruling is in the right direction to help quickly get white spaces devices onto the market, Ranveer Chandra of Microsoft Research, who built the world’s first white spaces network on the company’s Redmond campus, told me. “Making hardware able to get sensing right is very difficult, particularly for wireless microphones which all have different signals.” False positives are a problem when listening for wireless mics, says Chandra, because their signals are so low-powered. Being able to use the software-centric database approach will allow much speedier development compared to the alternative, which would mean coming up with new chip designs, he says.

Although Chandra and colleagues experimented with sensing too, the Microsoft network also demonstrates how a database could be used. They developed a cloud-based service to which a device can supply its location and receive an accurate description of the white spaces available, based on the position, power and height of nearby transmitters. They also built a website where you can check the white spaces in your area.

A new and very valuable sector is opening up. In a statement today FCC chairman Julius Genachowski pointed out that a so-called “junk band” of spectrum, which was allowed in 1985 to be unlicensed, supports billions of dollars of value. “The result was eventually a real game changer: Wi-Fi.” What he dubbed “super Wi-Fi”–long range Internet access like the Microsoft network, as well as another trial network connecting a school in rural Virginia–will be the first white spaces applications to come to market, he said.

This new entrant into the mobile ecosystem may complicate the business model for wireless companies currently spending billions on 4G cellular networks, though. They use licensed spectrum acquired at considerable cost for long-range communications.

Hear more from Microsoft at EmTech Digital.

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