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Transcript of Seminar Report
GOVERNMENT POLYTECHNIC, SADAR NAGPUR
(An Autonomous Institute of Government of Maharashtra)
SSEMINAREMINAR T TOPICOPIC
UWB TECHNOLOGYUWB TECHNOLOGY(ULTRA WIDE BAND TECHNOLOGY)
UNDER GUIDANCE OF
DINESH ALASPURE SIR
MADE BY
PRATIK SAWALE
ETX III YR ( 0904077 )
CERTIFICATE
THIS IS TO CERTIFY THAT, THE SEMINAR WORK ENTITLED
“UWB TECHNOLOGY”
HAS BEEN SUBMITTED BY
Mr. Pratik Sawale
3rd Year Electronics & Telecommunication
(0904077)
IN A SATISFACTORY MANNER AS A PART OF PARTIAL
FULFILLMENT OF DIPLOMA COURSE IN ELECTRONICS AND
TELECOMMUNICATION. IN GOVT. POLYTECHNIC, NAGPUR
DURING THE ACADEMIC YEAR
2011-2012
D. ALASPURE SIR Prof. S.V.TADAS
SEMINAR GUIDE HEAD OF DEPARTMENT
DEPARTMENT OF ELECTRONICS & TELECOMMUNICATION ENGG.
GOVT. POLYTECHNIC, NAGPUR.
(An autonomous institute of government of Maharashtra)
2011-2012
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ACKNOWLEDGEMENT ACKNOWLEDGEMENT
It is our more duty and responsibility to be loyal and grateful to those
who have shown us the path towards innovation and dynamism contributing
in a big way in complementing me for “UWB TECHNOLOGY” Seminar
report within the stipulated time.
It is worth mentioning here that as a guide, “Prof. MR. D.
ALASPURE SIR” has enlightened us for our seminar report. Let us be
honest to pay his utmost regards for his able guidance to which our seminar
report proved to be successful one.
We are insufficient to show our thankfulness to our Head of the
Department Prof. S. V. TADAS who at every point showed us the telescopic
way in respect of our seminar.
I also extend my thanks to all those teachers who have contributed to
make this seminar a success.
At last, I wish to avail myself of this opportunity, express a sense of
gratitude and love to my friends for their manual support, strength, help and
for everything.
Thank you!
Pratik SawaleElectronics and telecommunication
Enrol. No. 0904077
Page 2
INDEX INDEX
Contents
1. Introduction
2. What is UWB ?
3. How UWB works?
4. Narrowband communication & UWB
5. Modulation types
6. Spectrum
7. UWB Characteristics
8. Comparison with latest technologies
9. Application
10. Conclusion
11. References
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INTRODUCTIONINTRODUCTION
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" electromagnetic. 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.
UWB, or Ultra-Wide Band technology offers many advantages,
especially in terms of very high data transmission rates which are well
beyond those possible with currently deployed technologies such as
802.11a, b, g, WiMax and the like. As such UWB, ultra wideband
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technology is gaining considerable acceptance and being proposed for
use in a number of areas. Already Bluetooth, Wireless USB and others
are developing solutions, and in these areas alone its use should be
colossal.
UWB commonly refers to a signal or system that either has a large
relative bandwidth (BW) that exceeds 20% or a large absolute
bandwidth of more than 500 MHz. A 14 February 2002 report and
order by the federal communications commission (FCC) authorizes the
unlicensed use of UWB in 3.1--10.6 GHz. This is intended to provide
an efficient use of scarce radio bandwidth while enabling both high
data rate personal area network (PAN) wireless connectivity and
longer-range, low data rate applications as well as radar and imaging
systems.
WHAT IS UWB........??WHAT IS UWB........??
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Ultra-wideband is a radio technology that can be used at very low
energy levels for short-range high-bandwidth communications by
using a large portion of the radio spectrum.
Ultra-Wideband (UWB) is a technology for transmitting information
spread over a large bandwidth (>500 MHz) that should, in theory and
under the right circumstances, be able to share spectrum with other
users.
A significant difference between traditional radio transmissions and
UWB radio transmissions is that traditional systems transmit
information by varying the power level, frequency, and/or phase of a
sinusoidal wave. UWB transmissions transmit information by
generating radio energy at specific time instants and occupying large
bandwidth thus enabling a pulse-position or time-modulation. The
information can also be imparted (modulated) on UWB signals
(pulses) by encoding the polarity of the pulse, the amplitude of the
pulse, and/or by using orthogonal pulses. UWB pulses can be sent
sporadically at relatively low pulse rates to support time/position
modulation, but can also be sent at rates up to the inverse of the UWB
pulse bandwidth.
One of the valuable aspects of UWB radio technology is the ability for
a UWB radio system to determine "time of flight" of the direct path of
the radio transmission between the transmitter and receiver at various
frequencies. This helps to overcome multi path propagation, as at least
some of the frequencies pass on radio line of sight. With a cooperative
symmetric two-way metering technique distances can be measured to
high resolution as well as to high accuracy by compensating for local
clock drifts and stochastic inaccuracies.
Another valuable aspect of pulse-based UWB is that the pulses are
very short in space (less than 60 cm for a 500 MHz wide pulse, less
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than 23 cm for a 1.3 GHz bandwidth pulse), so most signal reflections
do not overlap the original pulse, and thus the traditional multipath
fading of narrow band signals does not exist. However, there still is
multipath propagation and inter-pulse interference for fast pulse
systems which have to be mitigated by coding techniques.
The fact that UWB transmissions have such a wide bandwidth means
that they will cross the boundaries of many of the currently licensed
carrier based transmissions. As such one of the fears is that UWB
transmission may cause interference. However the very high
bandwidth used also allows the power spectral density to be very low,
and the power limits on UWB are being strictly limited by the
regulatory bodies. In many instances they are lower than the spurious
emissions from electronic apparatus that has been certified. In view of
this it is anticipated that they will cause no noticeable interference to
other carrier based licensed users. Nevertheless regulatory bodies are
moving forward cautiously so that users who already have spectrum
allocations are not affected.
To date the FCC in the USA has approved UWB, ultra wideband
technology for indoor and short range outdoor communication, but
with restrictions on the frequencies over which the transmission can
spread as well as the power limits. This will enable the UWB ultra
wideband transmissions to communicate successfully, but without
affecting existing 'narrowband' transmissions.
HOW UWB WORKS........??HOW UWB WORKS........??
UWB differs substantially from conventional narrowband radio
frequency (RF) and spread spectrum technologies (SS), such as
Bluetooth Technology and 802.11a/b/g. A UWB transmitter works by
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sending billions of pulses across a very wide spectrum of frequency
several GHz in bandwidth.
The corresponding receiver then translates the pulses into data by
listening for a familiar pulse sequence sent by the transmitter. UWB’s
combination of larger spectrum, lower power and pulsed data
improves speed and reduces interference with other wireless spectra.
In the United States, the Federal Communications Commission (FCC)
has mandated that UWB radio transmissions can legally operate in the
range from 3.1 GHz up to 10.6 GHz, at a limited transmit power of –
41dBm/MHz. The result is dramatic short-range channel capacity and
limited interference.
Ultra Wideband (UWB) systems transmit signals across a much wider
frequency than conventional systems and are usually very difficult to
detect. The amount of spectrum occupied by a UWB signal, i.e. the
bandwidth of the UWB signal is at least 25% of the center frequency.
Thus, UWB's combination of broader spectrum and lower power
improves speed and reduces interference with other wireless spectra.
Specifically, UWB is defined as any radio technology having a
spectrum that occupies a bandwidth greater than 20 percent of the
center frequency, or a bandwidth of at least 500 MHz.
The most common technique for generating a UWB signal is to
transmit pulses with durations less than 1 nanosecond. It is Radio
technology that modulates impulse based waveforms instead of
continuous carrier waves.
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Table : Advantages and benefits of UWB communications over narrowband wireless technologies.
Advantage Benefit
Large channel capacityHigh bandwidth can support real-time high-definition
video streaming.
Ability to work with low SNRs Offers high performance in noisy environments.
Low transmit powerProvides high degree of security with low probability
of detection and intercept.
Resistance to jamming Reliable in hostile environments.
High performance in multipath
channelsDelivers higher signal strengths in adverse conditions.
Simple transceiver architecture
Enables ultra-low power, smaller form factor, and
better mean time between failures, all at a reduced
cost.
MODULATION TYPESMODULATION TYPES
UW
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The most common impulse radio concepts are based on Pulse Position
Modulation. These techniques use time shift of regularly timed pulses,
as it is shown at fig.1b for two modulation states.
Bi-Phase Modulation is modulation of the pulse polarity. Fig. 1c
shows it graphically. BPM is antipodal modulation method, whereas
PPM, when separated by one pulse width delay for each pulse
position, is an orthogonal modulation method. Therefore, BPM has
theoretically the 3dB gain in power efficiency. If PPM delays by one
pulse width, then BPM can send twice number of pulses and, twice the
information.
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PAM is not the preferred modulation method for most short-range
communication. AM signal which has smaller amplitude is more
susceptible to noise than that with larger amplitude.
On Off Keying is a modulation technique where the presence or
absence of a pulse represents pair of modulation states. The major
difficulty with OOK is the presence of echoes of the original or other
pulses. It makes difficult to determine the absence of a pulse. An
example of OOK is in fig. 2c.
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FREQUENCY SPECTRUMFREQUENCY SPECTRUM
The most part of energy of the UWB signal falls into the frequency
range from 3.1 to 10.6 GHz, and the energy spectral density doesn't
exceed limit determined by Part 15 of FCC
Regulations(-41dBm/MHz). Below 3.1 GHz the signal almost
disappears, its level is lower than -60. The more ideal the form of a
pulse formed with the transmitter, the less the energy goes out of the
1.61.9
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main range. But however that may be, the permissible deviation of the
pulse from the ideal form must be limited, hence the second purport.
The spectral range lower than 3.1 GHz is avoided not to create
problems for GPS systems whose accuracy of operation can suffer a lot
from outside signals even if their density is lower than -41.
The signal, in this way, extends over a large bandwidth (several
gigahertzs) and can be buried in the environment noise in a way that
does not interfere with other services.
UWB CHARACTERISTICSUWB CHARACTERISTICS
Extremely low transmission energy ( less than 1mW)
Very wide fractional and absolute RF bandwidth
Very high bandwidth within short range (200Mbps within 10m)
Extremely difficult to intercept
– Short pulse excitation generates wideband spectra – low energy
densities
– Low energy density also minimizes interference to other
services
Multipath immunity
Very short pulses
Carrier less transmission
High rate communication
Penetrate through walls
Commonality of signal generation and processing architectures
Radar
– Inherent high precision – sub-centimeter ranging
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– Wideband excitation for detection of complex, low RCS targets
Geo location/Positioning
– Sub-centimeter resolution using pulse leading edge detection
– passes through building blocks, walls, etc. (LOS not required)
Low Cost
– Nearly “all-digital” architecture– ideal for microminiaturization into a chipset
Frequency diversity with minimal hardware modifications
COMPARISON WITH LATEST TECHNOLOGIESCOMPARISON WITH LATEST TECHNOLOGIES
Wi-Fi
WiFi is an infrastructure-oriented technology and therefore has
difficulty communicating peer to peer. Also it was not designed for
streaming audio and video. The IEEE standards 802.11b and 802.11g
are used, both operates in the noisy 2.4 GHz ISM band and are subject
to interference. Transfer rate is slower with a top rate of 54Mbps.
Bluetooth
It was designed as a low power technology just to cut down the power
requirements of the wired technologies. Still it consumes 50x more
power as compared to UWB. The recent version of Bluetooth supports
up to a maximum of 12Mbps that is very low as compare to UWB. It
is also having problem of interference as it uses same band as that of
WiFi system.
UWB
A UWB signal centered at 2 GHz would have a minimum bandwidth
of 500 MHz and the minimum bandwidth of a UWB signal centered at
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4 GHz would be 1 GHz. The most common technique for generating a
UWB signal is to transmit pulses with durations less than 1
nanosecond. A traditional UWB transmitter works by sending billions
of pulses across a very wide spectrum of frequency several GHz in
bandwidth.
The corresponding receiver then translates the pulses into data by
listening for a familiar pulse sequence sent by the transmitter.
Specifically, UWB is defined as any radio technology having a
spectrum that occupies a bandwidth greater than 20 percent of the
center frequency, or a bandwidth of at least 500 MHz.
UWB APPLICATIONUWB APPLICATION
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
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Geolocation
Intelligent Transportation Systems, Electronic Signs, Smart
Appliances
Wireless Interconnection
Military:
Radar
Covert communications
Intrusion detection
Precision geo-location
Data links
CONCLUSIONCONCLUSION
UWB is in early stages of developments. It is proving its worth in
various fields with advantages like high bit rate, multimedia connectivity
to wireless personal area network. World is on the verge of freedom from
wires. UWB technology offers a solution for band-width, cost, power
consumption, and size requirements of next generation consumer
electronics.
A number of UWB components and system are in testing phase and
will be releasing in near future. UWB has been redefined as a high data
rate (480+ Mbps), short-range (up to 20 meters) technology that
specifically addresses emerging applications in the consumer electronics,
personal computing and mobile device markets. When compared to other
existing and nascent technologies capable of providing wireless
connectivity, the performance benefits of UWB are compelling.
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
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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.
REFERENCEREFERENCE
INFORMATION SOURCE
http://www.radio-electronics.com/info/wireless/index.php
Ultra-Wideband (UWB) Technology, Technology & Research at Intel
www.intel.com/technology/comms/uwb/
Ultra Wideband (UWB) Frequently Asked Questions (FAQ);
http://www.multispectral.com/UWBFAQ.html
UWB OVERVIEW
Ultra-wideband - Wikipedia, the free encyclopedia
en.wikipedia.org/wiki/Ultra-wideband
UWB MODULATION
http://www.urel.feec.vutbr.cz/ra2008/archive/ra2006/abstracts/088.pdf
UWB DETAILS
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http://www.antd.nist.gov/wctg/manet/NIST_UWB_Report_April03.pdf
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