1 ultra wideband: an emerging wireless technology king fahd university of petroleum & minerals...

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Ultra Wideband: an Emerging Wireless Ultra Wideband: an Emerging Wireless TechnologyTechnology

King Fahd University of Petroleum & MineralsKing Fahd University of Petroleum & MineralsElectrical Engineering DepartmentElectrical Engineering Department

EE571-Digital Communications IEE571-Digital Communications I

forward-looking and higher-risks researchforward-looking and higher-risks research

By Dr. Ali Hussein MuqaibelDr. Ali Hussein Muqaibel

2Ultra Wideband: an Emerging Wireless TechnologyDr. Ali Muqaibel

Topics Topics Definition Advantageous CRITICALITIES Applications Prototypes UWB Coexistence Issues Multiple Access UWB Communication Research Areas in UWB Communication Research groups & Companies

Communication

Electromagnatics

Transient Theory

Signal Processing

Radar


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

What is UWB ?


SIG

NA

L S

TR

EN

GT

H

AT

DIS

TA

NC

E

R

FREQUENCY (F)

1/F

< 1%

25% to >100%

UWB/NARROWBANDNARROWBAND DISCRIMINATION:

Pow

er S

pect

ral

Den

sity

rule of thumb: RF bandwidth/centre frequency 25% far from/near tonear to sinusoidal signal type considerable/negligiblenegligible difference in link attenuation

at lower/upper frequency

transient nature


Wireless Bandwidth in the Wireless Bandwidth in the MakingMaking

“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 pulse-position 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”

Serg

io

Verd

u


Historical Perspective on Ultra-Wideband (UWB)

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)

UWB Revolution

By 2000 Large companies had applied UWB to networking applications

UWB meets requirements for high throughput applications

Recycles scarce spectrum

History

<1900 Hertz generated pulsed spark discharge

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


SUMMARY

• spectrum efficiency (bits/Hz/s)

(system feature)

• flexible resource allocation (user, geographically, spectrally)

• versatility

(comms, sensing, positioning...)

• wide area/global coverage

• service integration

• Less coding/diversity requirements

Advantages for:

Comparison between NB & UWB

Narrowband

UWB

UWB

Narrowband

UWB

UWB


• New technologyNew technology: considerable development potential.• Nearly "all-digital"Nearly "all-digital", with minimal RF electronics.

• An LPD signature produces minimal interference to proximityminimal interference to proximity systemssystems , minimal RF health hazards minimal RF health hazards and is hardly interceptible. hardly interceptible.

• Extremely high data ratehigh data rate performance in multi-user networkmulti-user network applications.

• Can provide very fine range resolutionvery fine range resolution and precision distanceprecision distance and/or positioning measurement capabilities.

• Relativity immune to multipathimmune to multipath cancellation effects as observed in mobile and in-building environments.

• Low Power ConsumptionLow Power Consumption

Promised!: UWB System Advantages


• Coexistence (FCC)

• Multi-user capability

• Real world performance

• Implementation complexity

• Cost and competitiveness

• Connectivity with narrowband systems

UWB CRITICALITIES

NORMALNORMALmobile A

mobile B

mobile CInterference level

Do many UWB devices operating within a small area cause serious interference to existing licensed services ?

Do many UWB devices operating within a small area cause serious interference to existing licensed services ?


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.

1. they should be licensed !2. This technology should not use (re-use the paid spectrum

by others) the spectrum for free !3. This technology is still immature and we don’t know what

the interference problems may rise4. Extend the period of time to complete the interference

tests

Co-existence Issue: Reply Comments


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

Some UWB Applications


PrototypesTime 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 The radio has been tested to beyond 16 kilometers (10 miles).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 measuring the distance between radios with an accuracy of 3 cm (0.1 ft).(0.1 ft).

•A simplex 2.0 GHz data link with an effective average output power of 50 50 microWattsmicroWatts, a data rate of 5 Mbps5 Mbps at bit error rate (BER) of 0 (BER) of 0 with no forward error correction (FEC) and a range of 10 meters (32 ft) through two walls inside two walls inside an office building.an office building.


Received Signal 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:

u

s

N

k j

kNjc

kjfkrec utnudTucjTutwts

1

)(/

)( ),())()()((

kk=1=1

kk=2=2

kk=3=3

kk=4=4

TfNu =4 Tc

J=0 J=1 J=2 J=3


Pulse Position Modulation

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-1.5

-1

-0.5

0

0.5

1

1.5

t in nanoseconds

am

plit

ude

Reference Signals

received signal bit=0received signal bit=1template signal v(t)

2877.0 )/4( exp ])/(41[)35.0( 22 mmmrec withtttw

0 0.5 1 1.5 2-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time (ns)

Am

plitu

de /

Nor

mal

ized

to

A

Transmitted Gaussian Monocycle Waveform Wtr

Gaussian Monocycle


Gaussian, Monocycle and Doublet Waveforms

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time (ns)

Am

plitu

de /

Nor

mal

ized

to

A

Gaussian, Gaussian Monocycle and Doublet Waveforms

Gaussian Gaussian MonocycleDoublet

0 2 4 6 8 10 12

10-8

10-6

10-4

10-2

100

Frequency (GHz)

Am

plitu

de

/ N

orm

aliz

ed

to

1

Gaussian, Gaussian Monocycle and Doublet in Frequency Domain

Gaussian Gaussian MonocycleDoublet

• 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.


Frame Delay

)( )(ktr tw•The quantity represents the transmitted

monocycle waveform that nominally begins at time zero on the kth transmitter’s clock.

0 0.5 1 1.5 2-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time (ns)

Am

plitu

de /

Nor

mal

ized

to

A


Gaussian Monocycle

)( ftr jTtw •The quantity represents the transmitted monocycle in the j frame.

0 1 2 3 4 5 6 7 8 9 10-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time (ns)A

mpl

itude

/ N

orm

aliz

ed t

o A


Gaussian Monocycle

Time Frame


Uniform Pulse Train

j fk

tr jTtw )( )(

•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 2 4 6 8 10 12 14 16 18 20-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time (ns)

Am

plit

ud

e /

No

rma

lize

d t

o A

Uniform Pulse Train Spacing


0 2 4 6 8 10 12

10-8

10-6

10-4

10-2

100

Frequency (GHz)

Am

plitu

de

/ N

orm

aliz

ed

to

1

Gaussian Monocycle and Gaussian Monocycle Pulse Train in Frequency Domain

Gaussian Monocycle Monocycle Pulse Train


0 2 4 6 8 10 12 14 16 18 20-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time (ns)

Am

plitu

de /

Nor

mal

ized

to

AUniform Pulse Train Spacing


Random/Pseudorandom Time-Hopping Waveform

0 2 0 3


Spectrum of Random/Pseudorandom Time-Hopping

0 2 4 6 8 10 12

10-8

10-6

10-4

10-2

100

Frequency (GHz)

Am

plitu

de

/ N

orm

aliz

ed

to

1Gaussian Monocycle and Gaussian Monocycle Pulse Train in Frequency Domain

Gaussian Monocycle Monocycle Pulse Train


Pulse GeneratorPico-second Pulse Labs model

4050A/4100Step Generator

Driver

Tektronics 11801/HP 54120A

Digitizing Oscilloscope

Data Acquisition Unit

Balun andwideband transmitting antenna

Balun andwideband receiving antenna

Channel

Running LabView® 6.0i

pretrigger

trigger

trigger input

Time Domain (TD) Measurement Time Domain (TD) Measurement Setup Setup

LN Amplifiers


Acquired SignalsMonocycle

-60

-50

-40

-30

-20

-10

0

10

20

30

40

50

0.0 0.2 0.4 0.6 0.8 1.0

time (nano-seconds)A

mp

litu

de (

mV

)

Sent Impulse

-50

0

50

100

150

200

250

0.0 0.2 0.4 0.6 0.8 1.0

time (nano-seconds)

Am

pli

tud

e (

mV

)

•The transmitted signal get differentiated before it is decoded

•Multiple reflection cannot be avoided


Other Multipath Scenarios

2 4 6 8 10 12 14 16 18 20

-0.01

0

0.01

0.02

Time ns

Am

plitu

de in

V

close to ground

0 2 4 6 8 10 12 14 16 18 20

-0.02

0

0.02

Time ns

Am

plitu

de in

V

Higher


Areas in UWB Research Communication

Interference Measurements Antenna Design Spread Spectrum Techniques Multiple Access Techniques Multi-user detection Time Hopping Codes System Performance Evaluation under different

channel conditions (Gaussian, Raleigh) Coding and Diversity Applications Pulse Shaping and Modulation

MeasurementsMeasurements

Signal ProcessingSignal Processing& &

Receiver DesignReceiver Design

ModelsModels


Research Groups Ultra Wideband Working Group (UWBWG) www.uwb.org Ultra Lab Web ultra.usc.edu/ulab/ 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 Time Domain www.time-domain.com 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


Working Towards UWB Wireless Communication

Dr. Ali Hussein Muqaibel

[email protected]@kfupm.edu.saKing Fahd University of Petroleum & MineralsElectrical Engineering Department

Time Domain and RF Measurements Laboratory

http://tdl.ece.vt.edu/alihttp://tdl.ece.vt.edu/ali

MPRG

http://www.mprg.orghttp://www.mprg.org

1 ultra wideband: an emerging wireless technology king fahd university of petroleum & minerals...

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