If you’re anxious to see the latest in
wireless technologies and find out how
you can use them in your next design,
then the International CES is the place
to be—especially for the latest in
Ultra-Wideband (UWB) products. This
short-range technology provides speeds up to
480 Mbits/s at up to 10 m.
UWB has been around a few years, but it
hasn’t gotten much traction as a widespread
wireless technology yet. It has taken a while
to firm up the standard and put out chips that
can be embedded into other products. Several
factors have contributed to this slow-to-market
wireless option.
One of these is the challenge of making
OFDM chip sets that cover the 3.1- to
10.6-GHz band allocated to UWB by the
FCC. The early products focused on the three
lower bands from 3.1 to 4.7 GHz. Many such
chip sets were created, and today, most of
the main semiconductor vendors are offering
second-generation products, mostly in full
CMOS but a few yet with biCMOS SiGe.
Another factor has been the high price
of these chip sets. Of course, like all other
solid-state devices, prices will begin to drop
as volume increases. That volume has been
growing slowly, but there is a clear sign of
greater adoption.
The confusing and conflicting worldwide
spectrum allocations for UWB also limit
adoption. These allocations vary widely from
country to country so it has been hard to
make chip sets that fit all countries. On top of
that, there are still countries trying to firm up
their UWB assignments.
Only one group of bands is valid worldwide,
but that may be changing as new rules
and regulations come out of Asia and Europe.
A new technology called Detect and Avoid
(DAA) also may help as it is adopted, as it enables UWB products to avoid conflicts with
other services in the same spectrum. Most
new chip sets incorporate DAA.
As these challenges are met, the big problem
is getting greater visibility for the technology.
That has been the job of the WiMedia
Alliance, the organization that sets the standards,
performs certification tests for product
compatibility, and promotes the technology.
With the standard firmly in place and many
certified products, WiMedia’s job is primarily
educational, letting the engineering community
know just what UWB offers.
UWB is a great wireless technology, as it
has one of the highest data rates of any of the current crop of wireless standards. It can
handle up to 480 Mbits/s at ranges of about
2 to 3 m. The max range is about 10 m, but
speed typically drops to less than 100 Mbits/s
at that range. Yet that is still faster than most
other offerings. Range is limited by the very
low power requirement of –41.3 dBm/Hz of
bandwidth, which is what keeps UWB signals
from interfering with other overlapping services
in the spectrum.
Currently, the greatest use of WiMedia
UWB is wireless USB dongles and hubs. It
works great as a cable replacement. The USB
Implementer’s Forum standard protocol rides
on the WiMedia MAC and PHY. Dozens of
WiMedia USB products are out there now,
and you should see some new ones at CES.
Even some laptop manufacturers are embedding
wireless USB.
UWB is also being adopted in a variety of
wireless video products (Fig. 1). UWB can be
used to connect the set-top box to the HDTV
set and to the digital video recorder. Even
wireless HDMI is available
(Fig. 2). Audio
is another application, with products now
available for connecting surroundsound 5.1
components around the room. Even digital
cameras and camcorders now use UWB to
connect without wires.