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In the name of God

In the name of God. Smart Antenna for Mobile Communications. Shahrokh Valaee. The Final Goal. Anyone. Anywhere. Anytime. Cochannel Interference. Cellular Communications. Sectorization. Interference. Fading. What is a Smart Antenna?. What a Smart Antenna should do?.

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In the name of God

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  1. In the name of God Smart Antenna for Mobile Communications Shahrokh Valaee

  2. The Final Goal Anyone Anywhere Anytime

  3. Cochannel Interference Cellular Communications

  4. Sectorization

  5. Interference

  6. Fading

  7. What is a Smart Antenna?

  8. What a Smart Antenna should do? • Let the signal of the user go • Crush the interferer

  9. We produce signals in Time

  10. ... and in Space

  11. Temporal Spatial Detection Enumeration Estimation Localization Estimation Estimation Filtering Beamforming Statistical Signal Processing

  12. Time Frequency Period Space Wave Number Wave Length Filtering in Time Filtering in Space

  13. Signals are localized in space. Get the spatial samples using an Antenna Array

  14. Array Geometry

  15. Sonar Radar Seismology Medical Imaging Radio Telescopes Satellites Echo-beam Sounder Audio Conferencing Noise Cancellation Hands-free Mobile Communications Cellular Communications Array Processing Applications

  16. Multichannel DSP Processor

  17. G T2 T6 T1 T3 T4 T5 + Delay-and-Sum Beamformer • Assign the delays, Ti, such that the desired wavefront is received at the output.

  18. G T2 T1 d + Delay between two consecutive sensors: • D = d sin(G) / c • d: inter-element spacing • G: angle of arrival • c: wave speed

  19. G ... T1 Tk ... T3 T2 + Choose: Ti = -(i-1) D All signal components from sensors arrive at the adder with the same phase. Signal Amplified

  20. G ... T1 Tk ... T3 T2 + D D D D D W6 W5 W4 W3 W2 W1 + Similarities between Antenna Arrays and FIR Filters

  21. G W6 W5 W4 W3 W2 W1 + Minimum Variance Distortionless Response (MVDR) • Choose Wi such that: • beam in the direction of the desired signal • null in the direction of interference

  22. Desired Signal Desired Signal Interference Interference DS-BF MVDR

  23. Two Approaches: Switching Strategy Adaptive Strategy

  24. Switch between pre-defined beams

  25. In Adaptive beamforming the beam tracks the vehicle

  26. Comparing the two techniques

  27. Cell Radius Extension

  28. SDMA Space Division Multiple Access

  29. Benefits: • Lower transmission power • Smaller handsets • Longer battery life • Larger Capacity • Reduced interference • Reduced fading effect • Easier hand-over • Larger cell size • Smaller BER

  30. Some Active Research Centers: • 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

  31. 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

  32. There is a race on the way!

  33. Where do you stand in this race?

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