What you should know about Ultra-Wideband: proponents say Ultra-Wideband wireless technology can quickly and reliably move huge amounts of data throughout the car, making it well-suited for multimedia applications. It also could eliminate the cost, complexity and weight of conventional wire harnesses ... someday.

WHAT IS IT? Ultra-Wideband (UWB) is a short-range wireless communications technology that could be used in vehicles to eliminate the wires between devices and provide a high-speed data transfer link to outside information and entertainment sources. For example, with UWB it would be possible to wirelessly download a DVD-quality movie from a transmitter during refueling, then stream that video to multiple wireless screens in the car.

DOESN'T BLUETOOTH ALSO ELIMINATE WIRES? Bluetooth is fine for things like making wireless connections between from cell phones to car audio system, but its 700-kilobit/second data transfer rate is woefully inadequate compared to UWB's megabits/second of bandwidth.

HOW DOES IT WORK? UWB transmits billions of low-power pulses over a very wide radio spectrum, not the traditional high-power narrowband signal at a specific frequency. This eliminates the multi-path interference that occurs when a narrowband device like a cell phone receives the same signal multiple times. When that happens, the signals effectively cancel each other out. "UWB spreads each bit over 1.5 gigahertz of spectrum," says Jon Adams, director of Radio Technology and Strategy, Freescale Semiconductor Inc. (Austin, TX; www.freescale.com). "This means antenna location doesn't matter for cars. You'll get a signal." UWB's other big advantage is low, 100 microwatt, power consumption. This is 10 to 100 times less energy than Bluetooth requires, despite carrying data at a much faster rate.

WILL UWB REPLACE BLUETOOTH? Not in the near future, or directly. Bluetooth has struggled to meet its initial promise of hassle-free wireless connectivity, and is still far from perfect. However, a tremendous amount of work has been done to create the profiles and protocols needed for Bluetooth devices to talk to each other, which makes it the de facto wireless communication standard within the automobile. Nevertheless, Bluetooth must increase its low data transfer rate or risk being relegated to limited applications. One answer may be for Bluetooth to jettison its narrowband approach and adopt UWB as its radio communication technology. "That could solve a lot of problems," says Adams. "Bluetooth would do everything it does today, but the transfer rate would be faster and the power consumption lower."

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HOW DOES THIS REPLACE CONVENTIONAL WIRE HARNESSES? Proponents say the technology is so robust, reliable and power thrifty it could be used to convey a vehicle's electrical control signals through UWB chipsets located within every ECU. Sensors and switches fitted with inexpensive chips--like a Zigbee chip, a full two-way radio that fits in a 5[mm.sup.2] space--would send and receive the signals. Given that wire harnesses are heavy, costly and devilishly complex to design and assemble, a wireless option could greatly simplify matters. However, UWB would have to prove reliability beyond a reasonable doubt, which won't happen overnight.

AND THE DOWNSIDE OF UWB? Chipset production is just getting underway, so costs will be far higher than acceptable for automotive adoption for years. Also, there is currently no industry-wide standard outlining UWB's exact parameters which has given rise to a dispute over standards between two rival factions.

WHERE IS DEVELOPMENT HEADED? UWB will show up in high-end home theatres by the end of 2005. From there, chipsets will be modified to withstand harsh plant environments, and could be rolled out to the industrial control and sensor market as early as 2007. "Once you've gotten into the industrial space it's not that challenging to get to the automotive space," says Adams. He estimates the first automotive UWB chips could be ready for testing by 2008.

IS THE AUTO INDUSTRY INTERESTED? Adams: "Among the OEMs and major suppliers there are people who are completely uninterested because it sounds like a potential problem for them. But there also are those visionaries who realize there are risks that they need to take. Systems engineers who have to look at the broader picture are especially interested."

By Kermit Whitfield, Senior Associate Editor