Imagine the freedom of using a DVD player in one room to watch a movie in a
different room. Imagine using one controller box to watch different programs on
different televisions. Imagine connecting a digital camera to a television
without wires and without line-of-sight (LOS). Thanks to the emerging wireless
ultra-wideband (UWB) technology, consumers may soon be able to enjoy a wide
range of applications, which can utilize very high data-transfer rates, as
shown in Figure
.
Marconi
used spark-gap transmitters to send Morse-code pulse streams across a lab room
without wires. In 1901, after boosting power and building much larger antennas,
the radio pioneer used the device to transmit coded wireless signals across the
Atlantic Ocean. A century later, researchers are once again beaming short
electromagnetic pulses across their lab rooms. Over the years, the technology
has changed. Bulky coils and capacitors have been replaced with tiny integrated
circuits and tunnel diodes. Instead of ragged and erratic spark streams, there
are precisely timed sequences of specially shaped pulses that each last only a
few hundred trillionths of a second. And while Marconi's devices could
convey the equivalent of about 10 bits of data per second, UWB can send more
than 100 million bits of digital information in the same amount of time.
UWB technology is loosely defined as any wireless transmission scheme that
occupies a bandwidth of more than 25 percent of a center frequency, or more
than 1.5 GHz. The first consumer products using UWB chips are expected in late
2003.
The first UWB systems should be able to deliver bandwidth in the
40 to 60 Mbps range, with expectations of very high data transmission speeds,
from 100 to 500 Mbps, across distances of 5 to 10 m (16.4 to 32.8 ft).
Eventually, UWB could even hit data speeds in the 1-Gbps range, and reach
distances of up to 2 km (1.2 miles). This technology will lead to wireless
applications that are currently impossible. Engineers also expect UWB units to
be cheaper, smaller, and less dependent on power than current radio devices.