The FCC ruling limits the range of UWB transmissions to about ten metres, although longer ranges may be allowed in future once the question of interference has been sorted out. However, UWB is capable of a data rate of at least 100 megabits per second over such distances. So the way is now clear for commercial UWB products to provide wireless links between, say, personal computers and camcorders or music-players. Work is well advanced on a standard to enable UWB devices and peripherals to locate and communicate with each other. Such is the interest in the technology that heavyweights such as Intel are now actively investigating it, in addition to UWB firms such as Time Domain, Pulse-Link and Xtreme Spectrum.
Cellonics, a Singapore-based firm, has an interesting twist on UWB. Inspired by the firing of nerve cells, it has developed a circuit that generates high-frequency bursts of short pulses in response to an input signal, and which lends itself to UWB encoding. Cellonics recently demonstrated a short-range UWB system capable of transmitting at 11.4 megabits per second. It expects the first commercial applications for UWB to be in wireless-networking equipment for homes and offices. When higher-power transmission is allowed, says Lye Hoeng Fai, the firm’s boss, he expects UWB to appear in cellular systems.
Together, UWB and ad hoc architectures are a natural fit, since the UWB devices will have to locate each other and start communicating automatically, tasks that ad hoc networking readily facilitates. The two technologies are thought to have been used together in military applications for some time. UWB pulses, emitted apparently at random, are very difficult to detect or intercept, and are ideal for battlefield transmissions. UWB pulses can also be used for medical imaging, high-resolution radar, and proximity detection. But it is their potential use in communications that is arousing the most interest. Looking beyond 3G networks, and the patchwork of WI-FI and cellular networks that is often referred to as 4G, some are even referring to infrastructureless, ad hoc UWB networks as 5G.
Turned Upside Down
There is thus no shortage of new wireless technologies. But how these and other innovations will shape communications networks remains to be seen. On the one hand, there is a clear trend towards consolidation in wireless telecoms — with the likelihood being that there will be only a handful of global wireless operators by 2010. On the other, many emerging wireless technologies seem to signal a move to a less informal, more decentralised model along the lines of the Internet. Dr Johnson at Rice University suggests that ad hoc networking will create more scope for “mom and pop” network operators and free community networks, all stitched together in a casual, ever-shifting web.
Network operators will still be needed to carry long-haul traffic, but their role could become less (rather than more) important in future. In the process, the entire structure of the industry could shift from a top-down approach to one that is organised from the bottom up. There are already signs of this happening in the emerging area of commercial WI-FI networks, which allow individuals to club together to form a larger network. The business models and billing systems remain uncertain. But one thing is clear: it is still very early days for wireless data.