Cutting the Ties that Bind

Better than Bluetooth or WiFi, a robust new wireless scheme promises to deliver multimedia around the office and home without cables or fuss.

Persistent protests from America's Department of Defence, Federal Aviation Administration, satellite-radio companies, and firms hawking GPS (global positioning system) equipment have managed to curb the development of ultra-wideband (UWB) wireless technology for more than three years. They all leaned on the Federal Communications Commission (FCC), saying that UWB—which is, among other things, a nifty way of dispensing with the cables connecting home-entertainment gadgets to one another—would interfere with their navigational-guidance systems, radar and satellite transmissions. The big mobile-phone companies even warned the FCC that ultra-wideband transmissions would block telephone calls.

Caught in the middle, a couple of start-up firms trying to build chipsets for sending and receiving rivers of data using ultra-wideband have responded to each of the new technical hurdles in the hope of being given approval to sell their equipment to the public. Their patience paid off earlier this year, when the FCC at last approved the unlicensed use of the UWB spectrum (3.1 to 10.6 gigahertz).

One of the first to celebrate was Martin Rofheart, co-founder of XtremeSpectrum of Vienna, Virginia. Dr Rofheart has been busy showing off his UWB chipset's performance to consumer-electronics manufacturers from Japan and elsewhere, beaming flawless video and audio between various devices at speeds approaching 100 megabits per second. For applications where more than mere battery power is available, UWB can transmit data at speeds up to 500 megabits per second.

XtremeSpectrum has designed a chipset the size of a business card that electronics firms can incorporate into their own products. The development has proceeded in fits and starts. At one point, the FCC wanted to prevent ultra-wideband from being used in handheld devices. Because of their peripatetic nature, regulators feared that mobile gadgets would interfere with sensitive communications at airports or military installations. But handheld devices such as MP3 players are essential to ultra-wideband's consumer appeal. The technology will allow users to swap thousands of music tracks in seconds instead of minutes or even hours. A compromise was worked out, limiting the frequencies inside which XtremeSpectrum's chipset can operate.

The history of ultra-wideband differs from other wireless schemes, such as Bluetooth and the increasingly popular 802.11 protocol. Bluetooth is a low-power option for transmitting data over short distances at less than one megabit per second, while the 802.11 family offers maximum speeds of either 11 megabits per second or 54 megabits per second. But all three members of the 802.11 family consume too much power and are too expensive for battery-powered devices. In addition, neither Bluetooth nor the 802.11 family are ideal for handling the vast amounts of data exchanged between digital home- entertainment devices or battery-powered MP3 audio players.

However, both are being promoted by industry groups, and have been making inroads as alternatives to traditional hardwired forms of data transmission. Bluetooth's role is as a replacement for wires connecting computers to their peripherals and mobile phones to laptops. And 802.11b, a variant of the standard that has been given the more user-friendly name WiFi, is becoming popular for wireless computer networks in homes, offices and public spaces.

By contrast, ultra-wideband came out of the defence industry. Its origins go back to the 1950s, when military radar technicians were trying to improve existing equipment. Two decades later, their research led to something called “ultra-wideband synthetic aperture radar”. Spy planes and satellites use this kind of radar to see through dense ground cover to locate enemy troops and camouflaged equipment on the ground. It works by showering the target with rapid pulses of broad, low-frequency signals that punch their way through solid objects.

XtremeSpectrum has begun shipping its Trinity chipset to select customers. Dr Rofheart expects leading consumer-electronics firms to begin embedding the chipset into DVD players, VCRs, video-game consoles and home-theatre equipment in time for Christmas 2003. Industry watchers predict that the burgeoning home-networking market will reach $4 billion by 2006. That should leave plenty of room for XtremeSpectrum and its only competitor, Time Domain, which will unveil its own ultra-wideband chipset, called PulsON, later this year.

With their effective broadcasting range limited to only ten metres or so, ultra-wideband chipsets would appear to do what Bluetooth does and more. Apart from linking gadgets together wirelessly, the turf that Bluetooth had staked out for itself includes setting up spontaneous “personal area networks” that allow, say, a smart card in a person's pocket to buy a subway ticket automatically on the way past the barrier. However, with hundreds of times the bandwidth, ultra-wideband has a hefty advantage.

But there could still be room for both. Without the raw speed for swapping video and audio files, Bluetooth would be restricted to the home as a handy wireless-form of “wiring” for low-data-rate connections between computers and their peripherals. Meanwhile, UWB would do the heavy lifting when video and audio needed to move wirelessly around the building.