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[] Kampf um Frequenzen: U.S. Tries to Restrict 5-GHz Wireless LANs; Worried about interference with military,

Computerworld January 6, 2003

U.S. Tries to Restrict 5-GHz Wireless LANs; Worried about interference
with military

By Bob Brewin

The U.S. Department of Defense is seeking to restrict the use of
wireless LANs in the lower portion of the 5-GHz frequency band because
of concerns
about possible interference with military radar.

Portions of the 5-GHz band have already been assigned for unlicensed
WLANuse in the U.S., Europe and Japan. But in a draft position paper
submitted to the International Telecommunication Union (ITU), the U.S.
government said it wants the 5-GHz band protected for radar systems that
pick "smaller and less reflective targets out of background clutter."
That phrase refers to small boats or planes that terrorists could use to
attack U.S.
forces, said John Pike, a defense analyst at in
Washington. He added that the Defense Department is also concerned about
ability to detect stealth aircraft that can hide from most conventional
radar systems.

High Stakes

Badri Younes, director of spectrum management at the Pentagon,
acknowledged that the war on terrorism has raised the stakes for radar
Attackers "could be coming from anywhere," Younes said, adding that the
military has to be able to ensure that its radar systems can work
interference from WLANs.

The government's position paper was prepared for a meeting of the ITU in
Geneva on Nov. 11. The ITU, the United Nations body that oversees
spectrum allocations worldwide, plans to decide on the 5-GHz matter and
other issues at its quadrennial World Radio Conference (WRC) in Geneva

In the draft proposal, a copy of which was obtained by Computerworld,
the U.S. said it wants to restrict the use of Wi-Fi WLANtechnology
5.150 and 5.350 GHz. The government called for radar systems operating
in that band to be protected by a technique known as dynamic frequency
selection (DFS), which would shut down WLAN transmissions if a radar
signal was detected.

Bill Calder, a spokesman for Intel Corp., declined to specify the
DFSrestrictions being sought by the Pentagon. But he said that IT
vendors view them
as too conservative and are trying to reach a compromise with the
government before the WRC meeting.

"We do not want to see that low band unduly restricted," Calder said.

Younes said Pentagon officials are willing to work with companies to
devise a proposal that supports national security interests and the
needs of
WLAN vendors and users.

But Rich Redelfs, president and CEO of Atheros Communications Inc., a
Sunnyvale, Calif.-based maker of chip sets for 5-GHz WLANs, described
the attempt to limit use of the technology as "trying to put the genie
back in the bottle."

Clyde Ensslin, a spokesman for the National Telecommunications and
Information Administration, a division of the U.S. Department of
said the draft proposal represents the views of all federal agencies,
including the Federal Communications Commission.

The radar section pertains to both military and commercial radars,
including advanced systems that commercial pilots could use to detect
small planes,
Ensslin said.

Copyright © 2003 Computerworld, Inc

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