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The notion of faster, high-bandwidth, long-distance wireless networks got a boost as the U.S. Federal Communications Commission late last week voted to allow wireless devices using ultra-wideband radio technology to be developed and sold in the U.S.

Ultra-wideband proponents say the technology promises, eventually, a spatial capacity (bit/sec/square meter) 1,000 times greater than 802.11b and has the potential to support many more users - at much higher speeds and lower costs - than current wireless LAN systems.

LANs based on 802.11b have maximum data rate of 11M bit/sec, dropping to about 1M bit/sec at a distance of about 300 feet. Some ultra-wideband developers have claimed peak speeds, with current silicon, of 50M bit/sec over 30 feet. The actual distance and data rate will hinge on a range of variables, including signal power and antenna design.

The unanimous vote represented what commissioners called a "conservative" response to the opportunities, and the controversy, sparked by ultra-wideband.

But the vote is unlikely to defuse the battle. Groups as diverse as the Air Transport Association of America, Global Locate Inc., Nortel Networks Corp., Nokia Corp., Qualcomm Inc., and until recently the U.S. Department of Defense, lobbied against the move to broaden the use of ultra-wideband. They charge that ultra-wideband will interfere with Global Positioning System frequencies as well as other public safety and air safety wireless networks, cellular PCS systems and some satellite services. Tests have not been conclusive.

"The FCC said 'let's assume [ultra-wideband] might cause interference; now let's put these products in a frequency range where they won't interfere [with existing spectrum users],'" says Al Haase, CEO of Skycross Inc., a Melbourne, Fla., antenna builder that has adopted ultra-wideband principles to design a new generation of high-performance products. "Now, ultra-wideband should be able to move forward into actual products without the lawsuits and other obstacles that might have appeared if it was operating in lower frequencies."

The vote pledged the FCC to review this initial set of standards within six to 12 months, and to act quickly on any interference complaints.

The change to the FCC rules means that ultra-wideband communications and measurement devices will be restricted to one part of the spectrum, well away from the frequencies used by other technologies. Initial emission guidelines mean that the first products to market will likely be short-range, although it's hard to predict now what exactly what that range will be. A reasonable guess is ultra-wideband distances, depending on the type of network device, will be similar to Bluetooth, up to 30 feet, or to 802.11b, up to 300 feet.

There are also restrictions on how much electronic "noise" the devices can create in the lower frequencies.

Ultra-wideband uses short, low frequency, very fast pulses that are spread over a range of radio frequencies. By contrast, radios in existing wireless LANs create a continuous wave along a narrow frequency.

The technology is in use by the military and intelligence agencies, and some civilian agencies, in the form of highly secure communications and ground or building penetrating radar and imaging systems. Ultra-wideband transmitters in commercial data communications equipment are likely to result in relatively inexpensive devices with low power needs and very high data rates.

Advocates were jubilant. Staff at XtremeSpectrum Inc., a Vienna, Va., company creating ultra-wideband chips, broke open a case of champagne after the vote. Vice President of Marketing Chris Fisher says the company will move forward on building chips and selling these to an array of consumer electronics manufacturers. XtremeSpectrum is targeting video and audio distribution, such as transmitting video to a wall-mounted flat panel screen.

Among the best-known ultra-wideband vendors are Aether Wire and Location Inc., Multispectral Solutions Inc., Pulse-Link Inc., Time Domain Corp. and Xtreme Spectrum. Intel has a laboratory focused on ultra-wideband research. The Ultra Wideband Working Group, an ultra-wideband advocacy organization, lists about 150 organizational members, including Compaq, DaimlerChrysler AG, Intersil Corp., Lockheed Martin Corp., Motorola Inc. and the U.S. Air Force.

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