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5 GHz Wi-Fi spectrum on hold amid fear of interference to radar

WASHINGTON-Nearly two years after the Bush administration announced an agreement to free 5 GHz frequencies for Wi-Fi technology without causing interference to military radar systems, government and industry officials have yet to settle on a solution that fully resolves technical and national security issues.

Industry and government officials plan to huddle again this week to try to fix a problem they believed they had put behind them in early 2003.

“Government and industry engineers have been working together for months to find an acceptable way for 5 GHz devices to detect and avoid extraordinarily advanced radar signals. They’ve made enormous progress, and the key elements of a technical solution are already in place,” said Scott Harris, a lawyer representing a collection of major high-tech firms known as the Wi-Fi Alliance.

Harris said all the issues could be resolved in the next two months or so.

Meantime, the would-be injection of an additional 255 megahertz into the booming Wi-Fi business is still on hold.

The delay has created an embarrassment for an administration that expended considerable political capital on the matter at the 2003 World Radiocommunication Conference in Geneva. In January 2003, the National Telecommunications and Information Administration-an arm of the Commerce Department-boasted it had reached a consensus on 5 GHz Wi-Fi that it would present to other countries at WRC-03.

The agreement-formalized in FCC rules in 2003-requires wireless devices in the 5.250 to 5.350 GHz and the 5.470 to 5.725 GHz bands to employ dynamic frequency selection, or DFS. DFS is designed to identify military radar so Wi-Fi transmissions can avoid disrupting them.

Subsequent testing revealed 5 GHz Wi-Fi devices with DFS capability were mistakenly identifying other radio signals-including Wi-Fi-for military radar. As a result, Wi-Fi devices avoided using radio channels that were otherwise legitimate, resulting in inefficient use of the spectrum.

The trick became how to distinguish military radar from other radio signals. But that requires knowing characteristics of Pentagon radar, which is generally classified information.

Stakeholders suddenly realized what they were up against. The much-ballyhooed 5 GHz Wi-Fi policy had deteriorated into one big fire drill.

“We didn’t see the forest for the trees,” said Edmond Thomas, chief engineer of the Federal Communications Commission.

At the same time, Thomas said he believes relief is in sight. “We’re trying to thread the needle. … I think this is reaching closure very quickly,” he said.

Military brass is especially anxious to see the 5 GHz matter sorted out once and for all.

“The Department of Defense continues to work very closely with NTIA, FCC and representatives of the wireless industry to find a mutually acceptable technical solution that protects military radars while allowing Wi-Fi technology to proceed forward,” said Badri Younes, director of spectrum management at the Pentagon. “We are all working in good faith to resolve lingering technical issues, and I trust that we will achieve a win-win scenario. We believe that everyone is now sensitized to how critical radars are to national security.”

While federal regulators, the military and industry said they are optimistic about crafting a technical solution to the 5 GHz dilemma, the Bush administration is being mostly tight lipped about the situation and appears unwilling to go out on a limb about when the problem can be solved.

“These issues are being discussed, and we feel they can be resolved in the time we have,” said Clyde Ensslin, an NTIA spokesman. Ensslin refused to elaborate further.

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