Ultra wide band (UWB) development and applications
- the development and applications for ultra wide band technology
Just as many wireless technologies seem to be moving into
high volume production and becoming established a new technology has hit the
scene and is threatening to turn the industry upside down. Known as Ultra Wide
Band (UWB) this new technology has much to offer both in the performance and
data rates as well as the wide number of application in which it can be used.
Currently ultra wideband (UWB) technology has been proposed for or is being used
in applications from radar and sensing applications right through to high band
width communications. Furthermore ultra wide band, UWB can be used in both
commercial and military applications.
Unlike most other wireless technologies in use today, ultra
wideband (UWB) employs a totally different method of transmission. Rather than
using a specified frequency with a carrier, the technique that is used by
traditional transmissions, UWB uses what may be termed "time domain"
electromagnetics. In other words UWB uses pulses that spread out over a wide
bandwidth, rather than transmissions that are confined within a given channel.
It is the fact that UWB uses a different approach to wireless
or radio transmissions is part of the reason UWB development may appear to be
slow. With wireless transmissions using traditional techniques filling the
airwaves, care has to be taken when establishing UWB, that interference does not
result, and that whatever legislation is introduced, does not have to be changed
later.
Development
The development of UWB technology stems from work that was undertaken by the US
military into defining the behaviour of microwave networks to impulse or
transients. The work which was started in 1962. Traditionally networks had been
characterised according to their response in the frequency domain where
parameters such as amplitude and phase with respect to frequency are important.
However the new approach which was to spawn the first ideas about ultra wide
band or UWB technology looked at the impulse response.
At the time measurements were difficult to make as test
equipment with a sufficiently high bandwidth was not available. The fact that
the research was investigating an area where the supporting technologies such as
test equipment were not sufficiently developed placed restraints on the
research, but nevertheless investigations into the technology continued.
Having looked at the response of microwave networks to
impulses, the next major step forward occurred when the techniques were applied
to radiating systems. Once this work commenced in 1968 it soon became obvious
that UWB technology could be used for radar and communications applications.
The rate at which work was undertaken was increased in the
1970s and 80s as the supporting technologies became available. During this
period it was termed carrier free or impulse technology. The term
ultra wide band or UWB was only coined in the later 1980s by the US Department
of Defense. However by this time many patentees had been awarded and a
considerable degree of development had been invested in the technology.
Development of UWB technology was primarily intended for
military applications and it was classified. As a result little development took
place in the commercial arena. However in the years following 2000, commercial
wireless communications became established. Technologies such as 802.11 (Wi-Fi),
Bluetooth and others became established. These paved the way, and showed the
flexibility offered by wireless communications for a very wide variety of
applications from mobile phone peripheral connectivity to mobility and
connectivity for laptops. These technologies and others grew rapidly.
Accordingly commercial applications for ultra wideband UWB became very apparent
and commercial exploitation started
One of the major limitations to the speed at which UWB could
enter the commercial marketplace was legislation. In view of the fact that UWB
occupies a wide bandwidth, even though at a low power level, it has to exist
alongside traditional transmissions without causing any undue interference.
Accordingly the legislative bodies and in particular the FCC in the USA have
been proceeding with caution. Any changes in direction required will be far more
difficult to address in later years once UWB technology is firmly established.
Despite this UWB transmissions are allowed, provided that they remain within a
given power density and frequency profile. This ensures that the allowed
transmission levels do not cause any noticeable interference to existing
transmissions.
Applications
There is a wide number of applications that UWB technology can be used for. They
range from data and voice communications through to radar and tagging. With the
growing number of way in which wireless technology can be used, the list is
likely to grow.
Although much of the hype about ultra wideband UWB has been
associated with commercial applications, the technology is equally suited to
military applications. One of the advantages is that with the pulses being
spread over a wide spectrum they can be difficult to detect. This makes them
ideal for covert communications.
Commercial:
- High speed LAN / WAN ( >20 Mbps)
- Avoidance radar
- Altimeter (aviation)
- Tags for intelligent transport systems
- Intrusion detection
- Geolocation
Military:
- Radar
- Covert communications
- Intrusion detection
- Precision geo-location
- Data links
Summary
With the growing level of wireless communications, ultra wide band UWB offers
significant advantages in many areas. One of the main attractions for WAN / LAN
applications is the very high data rates that can be supported. With computer
technology requiring ever increasing amounts of data to be transported, it is
likely that standards such as 802.11 and others may not be able to support the
data speeds required in some applications. It is in overcoming this problem
where UWB may well become a major technology of the future.
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