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Ultra-Wideband: Our Vision
In the
future, homes, cars, offices, and many other environments will be
intelligent. These environments will be able to sense objects and the
presence of people in order to perform many different functions,
including adjusting the environment to suit the individual based on
the time of day or day of the week, monitoring the elderly or children
for health and safety purposes, or performing security functions, just
to name a few. These devices will almost certainly need to be small,
inexpensive, rapidly deployable and numerous,. Thus, there will be a
need for power efficient wireless networks that are capable of both
sensing the environment as well as communications. There are a number
of factors that make the realization of this vision challenging. They
include:
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The network must be
able to perform both communications and sensing functions including
accurate position location.
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Network devices must be cheap and power efficient since they will be
deployed rapidly and cannot rely on fixed infrastructure.
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The communications system will be made up of a large number of
wireless devices that must share an already crowded spectrum.
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Innovation in this area will come fast and furious challenging the
FCC’s ability to allocate spectrum effectively.
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The network must be able to control access for hundreds of devices
within close proximity.
Ultra Wideband (UWB) is a
promising technology that has the potential to address each of the
above technological challenges. UWB networks utilize extremely
wideband signals typically using ultra-short pulses (impulse-based
UWB). Through the use of pulse-based, low duty cycle waveforms, the
physical layer of UWB networks is capable of providing both
communications and sensing. Specifically, short (picosecond or
nanosecond) pulses have the ability to provide extremely accurate
position information, especially when used in a network. UWB signals
also have very low power spectral density which means that ideally
they cause little interference to narrowband systems, or to each other
when designed correctly. This allows unregulated use of the spectrum
(or at least minimal regulation). Unregulated spectral use allows
innovation to flourish. Additionally, we believe that ultimately this
is a more efficient use of the spectrum which is a precious resource.
Such efficient use will
be absolutely necessary when large numbers of wireless devices attempt
to share the spectrum. UWB systems are also possibly more efficient
and certainly less expensive than intelligent systems which attempt to
search for “holes” in the spectrum. However, there are currently
several research issues associated with the use of UWB networks. Thus,
the use of UWB-based networks to meet the challenges listed above will
require substantial research some of which are ongoing or currently
being initiated.
The aspects of UWB
we are currently investigating are:
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