Wednesday, November 5, 2008

Wi-Fi on Amphetamines

Almost lost in all the election media frenzy was the FCC’s approval yesterday of a plan to open the white spaces between broadcast TV channels to cell phones, laptops and a wide range of portable consumer electronics devices. These frequencies between 54-698 MHz are highly prized, as they can easily penetrate buildings and other obstructions; they also enable far faster communication than you can get over Wi-Fi, which operates at 2.4 and 5 GHz.

“White spaces are the blank pages on which we write our broadband future,” said Democratic Commissioner Jonathan Adelstein during the meeting. “Let's hope this is not just Wi-Fi on steroids but Wi-Fi on amphetamines as well because it will be that fast.”

How fast is that? Cable modems—the fastest it gets right now—can theoretically deliver 20 Mbps downloads, though mine typically tops out at 5 Mbps when no one else is online and the wind is right. While I haven’t seen any test results, some sources are predicting multi-channel MIMO white-space modems in a few years delivering 40 Mbps—an 8x improvement over the best you can hope for currently.

I Hear You
The decision was hard fought, with Sergey Brin, Larry Page and Bill Gates personally lobbying the commissioners on the importance of opening up these channels, which they claimed would spur both competition and innovation. AT&T and Verizon—who paid heavily for C Block spectrum in the FCC’s recent auction—were against the idea, though their obvious economic self interest didn’t contribute to their credibility.

The strongest opposition came from the entertainment industry, who feared that unlicensed devices on these frequencies would interfere with wireless microphones. Even Dolly Parton weighed in, asking the commissioners to delay the hearing so she could comment further. Dolly Parton appearing before the buttoned-down FCC would certainly have caused enough of a media circus to break into the evening news—and derail the proceedings. In the end Chairman Martin ruled that the public interest was best served by opening up the white spaces for unlicensed portable devices.

Trust and Verify
Low-power, unlicensed wireless devices are covered by Part 15 of Title 47 of the Code of Federal Regulations. Under Part 15 compliance is a self-approval process where the manufacturer performs the necessary tests and determines that the device complies with the rules. The FCC makes the rules and trusts the manufacturer to verify compliance. Every low-power wireless device you own has a Part 15 compliance stamp on it somewhere.

In this case the FCC went one step further, conducting extensive device tests to verify that in fact unlicensed devices could co-exist in the white spaces without causing interference to legacy users. “Normally, the Commission adopts prospective rules about interference and then certifies devices to ensure they are in compliance,” Martin said in a statement. “Here, we took the extraordinary step of first conducting this extensive interference testing in order to prove the concept that white space devices could be safely deployed.”

Hang In There
While the FCC ruling has immediate effect, the white spaces won’t open up until next February, when all U.S. analog TV signals go off the air. It will then take some time for consumer electronics manufacturers to get their new wireless devices certified and into production, and it will take longer to get the wireless infrastructure in place.

So “Wi-Fi on amphetamines” isn’t right around the corner, but it is coming soon. It will be worth the wait.

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