UWB has been around for many years in various forms. But in the next few months it will finally make its first appearance in consumer-electronics products. This ought to be cause for rejoicing, for UWB is a low-power technology that supports data-transfer rates measured in hundreds of megabits per second over short distances (such as between two devices in the same room). UWB thus has the potential to do away with the spaghetti behind computers and home-entertainment systems. It will allow camcorders and digital cameras to beam images directly to televisions or PCs. It could even enable your computer to update your portable music player with your latest downloads automatically as you walk past.
Unlike conventional radio transmitters, which transmit on a particular frequency and which cannot be picked up if the receiver is slightly mistuned, UWB devices broadcast at very low power over an extremely wide band of frequencies. This has the advantage that UWB signals can be picked up by suitably designed receivers, but resemble background noise to conventional radio receivers, which are listening on one particular frequency. Conventional and UWB radios can therefore coexist. And that is why America’s telecoms regulator, the Federal Communications Commission (FCC), ruled in February 2002 that UWB devices could operate across a broad swathe of the radio spectrum, from 3.1GHz to 10.6GHz, without requiring spectrum licences.
This unusual approach makes UWB very different from Wi-Fi and Bluetooth, two other unlicensed radio technologies. Rather than operating (as Wi-Fi and Bluetooth do) in unlicensed garbage bands, the radio equivalent of unused wasteland, UWB devices operate across frequency bands that are already licensed for various other purposes, including satellite broadcasts, global-positioning systems and telematics. By keeping power levels low, however, UWB devices can co-exist with these existing systemsan approach known as underlay access. Where Wi-Fi exploits the radio equivalent of wasteland, UWB is like being able to build underground. Its novel approach liberates huge amounts of hitherto untapped transmission capacity.