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020406080
100U
SA
Japa
n
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
