forward-looking and higher-risks research
Ultra Wideband: an Emerging Wireless
Technology
By
Dr. Ali Hussein Muqaibel
King Fahd University of Petroleum & Minerals
Electrical Engineering Department
EE571-Digital Communications I
1
Topics
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Definition
Advantageous
CRITICALITIES
Applications
Prototypes
UWB Coexistence Issues
Multiple Access UWB Communication
Research Areas in UWB Communication
Research groups & Companies
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
Communication
Electromagnatics
Transient Theory
Signal Processing
Radar
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What is UWB ?
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UWB : the use of extremely short pulses instead of continuous
waves to transmit information.
The pulse directly generates a very wide instantaneous bandwidth
signal according to the time-scaling properties of the Fourier
transform relationship between time and frequency.
UWB is an “old” technology with the potential to
significantly impact the traditional way of
managing the spectrum
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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UWB/NARROWBAND DISCRIMINATION:
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rule of thumb: RF bandwidth/centre frequency 25%
far from/near to sinusoidal signal type
considerable/negligible difference in link attenuation
at lower/upper frequency
transient nature
Density
Power Spectral
SIGNAL STRENGTH
AT DISTANCE R
25% to >100%
< 1%
1/F
FREQUENCY (F)
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Wireless Bandwidth in the Making
“An intriguing alternative which may eventually become practical,
and even legal, for short-range communication between static
terminals is ultra-wideband impulse radio.”
“In fact, the principle of impulse radio is firmly grounded in
information theory: maximum power efficiency is achieved by pulseposition modulation in an infinite bandwidth channel”
“although the whole band occupied by the transmission, say, from
DC to a few gigahertz is “owned” by other systems, much of it is
unused at any given time. Thus, reasonable receiver sensitivity can
indeed be achieved with very low transmitted power”
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Historical Perspective on Ultra-Wideband (UWB)
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History
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<1900 Hertz
generated pulsed
spark discharge
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In 1940’s used for
radar
In 1970’s matured
as solution for
covert military
communications
In 1990’s
developed for
location and
positioning
applications
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Today’s
Environment
Scarcity of available
spectrum for new
applications
Proliferation of
digital consumer
electronics devices
Advances in
microprocessor
power
Numerous
improvements in
process technology
(such as SiGe,
CMOS and GaAs)
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UWB Revolution
By 2000 Large
companies had
applied UWB to
networking
applications
UWB meets
requirements for
high throughput
applications
Recycles scarce
spectrum
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Comparison between NB & UWB
SUMMARY
• spectrum efficiency (bits/Hz/s)
Advantages for:
Narrowband
(system feature)
• flexible resource allocation
(user, geographically, spectrally)
• versatility
UWB
UWB
(comms, sensing, positioning...)
• wide area/global coverage
Narrowband
• service integration
UWB
• Less coding/diversity requirements
UWB
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Promised!: UWB System Advantages
• New technology: considerable development potential.
• Nearly "all-digital", with minimal RF electronics.
• An LPD signature produces minimal interference to proximity systems ,
minimal RF health hazards and is hardly interceptible.
• Extremely high data rate performance in multi-user network applications.
• Can provide very fine range resolution and precision distance and/or
positioning measurement capabilities.
• Relativity immune to multipath cancellation effects as observed in mobile and
in-building environments.
• Low Power Consumption
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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UWB CRITICALITIES
• Coexistence (FCC)
• Multi-user capability
• Real world performance
mobile B
NORMAL
mobile A
• Implementation complexity
mobile C
Interference level
• Cost and competitiveness
• Connectivity with narrowband systems
Do many UWB devices operating within a small area cause serious
interference to existing licensed services ?
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Co-existence Issue: Reply Comments
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1.
2.
3.
4.
Wide agreement that this technology is very promising, there is a
very broad applications range
Strong concern to allow the UWB devices operate below 2 GHz or
even below 3 GHz.
they should be licensed !
This technology should not use (re-use the paid spectrum by
others) the spectrum for free !
This technology is still immature and we don’t know what the
interference problems may rise
Extend the period of time to complete the interference tests
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Some UWB Applications
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Digital Video Networks
Short range radios
High Speed (tens Mb/s) WLANs, microphones, etc.
Precision Geo-location Systems
Industrial RF Monitoring Systems
Collision Avoidance Sensors
Motion and Intrusion Detection Radar
Automobile and aircraft proximity radar, including
precision automatic landing
Subsurface in-ground penetration radar
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Prototypes
Time Domain has built several prototypes including the following:
•A full duplex 1.3 GHz system with an average output power of 250 microWatts,
and a variable data rate of either 39 kbps or 156 kbps. The radio has been tested
to beyond 16 kilometers (10 miles).
•A full duplex 1.7 GHz walkie-talkie with an average output power of 2 milliWatts,
a data rate of 32 kbps and a range of 900 meters. The unit was also capable of
measuring the distance between radios with an accuracy of 3 cm (0.1 ft).
•A simplex 2.0 GHz data link with an effective average output power of 50
microWatts, a data rate of 5 Mbps at bit error rate (BER) of 0 with no forward
error correction (FEC) and a range of 10 meters (32 ft) through two walls inside
an office building.
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Received Signal
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Multiple Access, when the physical layer is UWB, is
achieved by using time hopping codes
When the number of users is Nu , the received signal is:
N

st     wrec (t   k (u )  jTf  c (jk ) (u )Tc  d ( kj /)N  (u ))  n(t , u )
u
s
k 1 j  
J=0
J=1
J=2
J=3
k=1
k=2
k=3
k=4
Nu =4
Tf
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
Tc
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Pulse Position Modulation
Reference Signals
1.5
Transmitted Gaussian Monocycle Waveform Wtr
received signal bit=0
received signal bit=1
template signal v(t)
1
1
Gaussian Monocycle
0.8
0.5
0.4
0.2
amplitude
Amplitude / Normalized to A
0.6
0
-0.2
-0.4
0
-0.6
-0.5
-0.8
-1
0
0.5
1
1.5
2
Time (ns)
-1
-1.5
0
0.1
0.2
0.3
0.4
0.5
0.6
t in nanoseconds
0.7
0.8
0.9
1
wrec (t  0.35)  [1  4 (t /  m ) 2 ] exp (4 t /  m  ) with  m  0.2877
2
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Gaussian, Monocycle and
Doublet Waveforms
Gaussian, Gaussian Monocycle and Doublet Waveforms
1
Gaussian, Gaussian Monocycle and Doublet in Frequency Domain
Gaussian
Gaussian Monocycle
Doublet
0
0.8
10
Amplitude / Normalized to 1
Amplitude / Normalized to A
0.6
0.4
0.2
0
-0.2
-0.4
-2
10
-4
10
-6
10
-0.6
Gaussian
Gaussian Monocycle
Doublet
-0.8
-1
0
0.1
0.2
0.3
•
•
•
•
•
0.4
Time (ns)
0.5
0.6
0.7
-8
10
0.8
0
2
4
6
8
Frequency (GHz)
10
12
2GHz (>1Mhz) , noise like.
fc typically 650 MHz – 5MHz.
Tightly controlled pulse-to-pulse interval.
Pulse width 0.2 –1.5 nanoseconds.
Pulse-to-Pulse interval 100-1000 nano-seconds.
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Frame Delay
Transmitted Gaussian Monocycle Waveform Wtr
1
Gaussian Monocycle
0.8
•The quantity wtr (t ) represents the transmitted
monocycle waveform that nominally begins at time
zero on the kth transmitter’s clock.
(k )
Amplitude / Normalized to A
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
0
0.5
1
1.5
2
Time (ns)
Transmitted Gaussian Monocycle Waveform Wtr
1
Gaussian Monocycle
0.8
0.6
Amplitude / Normalized to A
•The quantity wtr (t  jT f ) represents the transmitted
monocycle in the j frame.
Time Frame
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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1
2
3
4
5
Time (ns)
6
7
8
9
16
10
Uniform Pulse Train
Uniform Pulse Train Spacing
1
0.8
•Uniform Pulse train: the frame time (Tf)
may by 100 to 1000 times the monocycle
width, resulting in a signal with very low
duty cycle.
•Multiple Access signals composed of
uniformly spaced pulses are vulnerable to
occasional Catastrophic Collisions.
•In frequency domain (Normalized)
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
Uniform Pulse Train Spacing
0
2
4
6
8
10
12
Time (ns)
14
16
18
Gaussian Monocycle
Monocycle Pulse Train
0
10
-2
10
-4
10
-6
10
-8
10
0
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Gaussian Monocycle and Gaussian Monocycle Pulse Train in Frequency Domain
Amplitude / Normalized to 1
 j  wtr (t (k )  jTf )

Amplitude / Normalized to A
0.6
2
4
6
8
Frequency (GHz)
10
12
17
Random/Pseudorandom TimeHopping Waveform
Uniform Pulse Train Spacing
1
0.8
Amplitude / Normalized to A
0.6
0
0.4
2
3
0
0.2
0
-0.2
-0.4
Uniform Pulse Train Spacing
-0.6
-0.8
-1
0
2
4
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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8
10
12
Time (ns)
14
16
18
20
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Spectrum of Random/Pseudorandom TimeHopping
Gaussian Monocycle and Gaussian Monocycle Pulse Train in Frequency Domain
Gaussian Monocycle
Monocycle Pulse Train
0
Amplitude / Normalized to 1
10
-2
10
-4
10
-6
10
-8
10
0
2
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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6
8
Frequency (GHz)
10
12
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Time Domain (TD) Measurement Setup
Tektronics 11801/HP
54120A
Digitizing Oscilloscope
Running
LabView® 6.0i
LN Amplifiers
Data Acquisition
Unit
trigger
input
Channel
Balun and
wideband transmitting antenna
Balun and
wideband receiving antenna
pretrigger
trigger
Pulse Generator
Pico-second Pulse Labs model
4050A/4100
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
Step Generator
Driver
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Acquired Signals
Sent Impulse
Monocycle
250
50
40
200
30
Amplitude (mV)
Amplitude (mV)
20
150
100
10
0
-10
0.0
0.2
0.4
0.6
0.8
1.0
-20
50
-30
-40
0
0.0
0.2
0.4
0.6
0.8
1.0
-50
-60
-50
time (nano-seconds)
time (nano-seconds)
•The transmitted signal get differentiated before it is decoded
•Multiple reflection cannot be avoided
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Other Multipath Scenarios
close to ground
Amplitude in V
0.02
0.01
0
-0.01
Amplitude in V
2
4
6
8
12
10
Time ns
14
16
18
20
Higher
0.02
0
-0.02
0
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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4
6
8
12
10
Time ns
14
16
18
20
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Areas in UWB Research Communication
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Interference Measurements
Measurements
Antenna Design
Spread Spectrum Techniques
Signal Processing
Models
&
Multiple Access Techniques
Receiver Design
Multi-user detection
Time Hopping Codes
System Performance Evaluation under different
channel conditions (Gaussian, Raleigh)
Coding and Diversity Applications
Pulse Shaping and Modulation
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Research Groups
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Ultra Wideband Working Group (UWBWG) www.uwb.org
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Ultra Lab Web ultra.usc.edu/ulab/
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University of Texas, Center of Ultra Wideband Research and
Engineering sgl.arlut.utexas.edu/asd/Cure/impulse.html
Time Domain Laboratory (VT) tdl.ece.vt.edu
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Time Domain www.time-domain.com
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Bibliography Of Ultra-wideband Technology
www.aetherwire.com/CDROM/General/biblio.html
Presentations from the 1st European Ultra Wideband Workshop
www.cordis.lu/ist/ka4/mobile/uwb_workshop.htm
Ultra Wideband (UWB) Frequently Asked Questions (FAQ)
www.multispectral.com/UWBFAQ.html
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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Working Towards UWB Wireless Communication
Dr. Ali Hussein Muqaibel
muqaibel@kfupm.edu.sa
King Fahd University of Petroleum & Minerals
Electrical Engineering Department
Time Domain and RF Measurements Laboratory
http://tdl.ece.vt.edu/ali
MPRG
http://www.mprg.org
Ultra Wideband: an Emerging Wireless Technology
Dr. Ali Muqaibel
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