020406080

100U

SA

Japa

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Eur

ope

Asia/

Pac

ific

Res

t of

Internet and Mobile Subscriber Penetration Forecast (2004)

Internet

Mobile

Anyone Anywhere Anytime

Cochannel

Interference

Interference

• Let the signal of the user go

• Crush the interferer

Estimation

Filtering

Temporal

Detection

Estimation Estimation

Beamforming

Spatial

Enumeration

Localization

Time Space

Frequency Wave Number

Period Wave Length

Filtering in Time

Filtering in Space

Signals are localized in space.

Get the spatial samples using an

Antenna Array

Array Processing Applications

• Sonar

• Radar

• Seismology

• Medical Imaging

• Radio Telescopes

• Satellites

• Echo-beam Sounder

• Audio Conferencing

• Noise Cancellation

• Hands-free Mobile Communications

• Cellular Communications

Multichannel DSP

Processor

M USIC

ESPRIT

W SM

......

H igh Resolution Techniques

Delay-and-SumBeam form er

M VDR

GSC

......

Low Resolution Techniques

Array Processing Techniques

T2 T6T1 T3 T4 T5

+

G

• Assign the delays, Ti, such that the desired wavefront is received at the output.

Delay between two consecutive sensors:

T2 T1

+

G

d

D = d sin(G) / c

• d: inter-element spacing

• G: angle of arrival

• c: wave speed

... T1Tk ... T3 T2

+

GChoose:

Ti = -(i-1) D

All signal components from sensors arrive at the adder with the same phase.

Signal Amplified

... T1Tk ... T3 T2

+

G

D D D D DW1W2W3W4W5W6

+

W1W2W3W4W5W6

+

G

Choose Wi such that:

• beam in the direction of the desired signal

• null in the direction of interference

Desired Signal Interference

Desired Signal Interference

Space Division Multiple Access

SDMA

Benefits:

• Reduced interference

• Reduced fading effect

• Easier hand-over

• Larger cell size

• Smaller BER

• Lower transmission power

• Smaller handsets

• Longer battery life

• Larger Capacity

Center for Communications Research - University of Bristol

Center for Personkommunikation - Aalborg University

Center for Wireless Telecommunications - Virginia Tech

Cornell University Blind Equalization Research Group

Image Processing & Communications Lab - Queen's University, Ontario

INFOPAD, University of California at Berkeley

Mobile Computing at University of Washington

Mobile Computing Laboratory, Columbia University

Mobile Computing Research at Purdue University

Some Active Research Centers:

Mobile and Portable Radio Research Group (MPRG), Virginia Tech.

Radio Systems Group at the University of Auckland

Research Group for RF Communications - University of Kaiserlautern

Royal Institute of Technology - Signal Processing

Smart Antenna Research Group - Stanford University

Systems and Control Group, Uppsala University

Telecommunications and Information Systems Engineering - University of Texas at Austin

Telecommunications at Georgia Tech

Uppsala University, Signals and Systems

WINLAB, Rutgers University

Wireless Technology Group - McMaster University