1. Introduction to Smart Antenna Advisor ： Dr. Wen-Jye Huang Student ： Chi-Ting Wu 2004.08.18 Wireless Communication LAB

2. OUTLINE ► Introduction ► What is Smart Antenna ? ► Why Smart Antenna ? ► How Smart Antenna works ?  ULA  UCA ► Conclusion

3. Introduction ► Rapid growth of wireless communication ► Multi-services requirement ► Effective usage of frequency band ► Classic antennas are omni-directional smart antenna smart antenna

4. What is Smart Antenna ► Concept of SDMA system ► Arrange in a particular geometric form ► Use few methods to change EM wave pattern  Switched beam system  Adaptive antenna system

5. Switched beam system 。 select one of several beams to enhance received signals

6. Adaptive antenna system 。 adaptive beam system can adjust its antenna pattern to enhance the desired signal 。 null or reduce interference 。 collect correlated multipath power

7. Why Smart Antenna ► ► Higher capacity (traffic/area) ► ► Better transmission quality and/or coverage

8. Why Smart Antenna ► ► Reduction of transmitter power ► ► Reduction of delay spread ► ► Accurate user position estimation Fixed cell shapeDynamic cell shape

9. Limiting effects of the wireless channel ► ► Multi-path propagation gives rise to ► ► fading ► ► inter-symbol interference ► ► time variation of signals ► ► Co-channel interference gives rise to ► ► increased noise level and hence greater errors

10. Multi-path propagation ► ► Multipath components suffer different delays ► ► This gives rise to ISI ► ► reject or stimulate multipath components by changing their radiation patterns ► ► significantly reduce the requirements of equalization and/or increase CINR Mobile Smart Antenna LoS MP

11. Co-channel interference ► ► Interference from other directions than wanted user ► ► suppress unwanted user by placing nulls in directions of unwanted signals ► ► improved transmission quality and/or system capacity Mobile 2 Smart Antenna LoS MP Mobile 1 Interference

12. How Smart Antenna works ► Uniform Linear Array geometry ► Uniform Circular Array geometry

13. Uniform Linear Array geometry

14. Base-band signal

15. Uniform Circular Array geometry

18. Conclusion ► ► Smart Antenna offer new ways to combat and/or exploit the spatial channel ► Smart Antennas reduce co-channel interference, improve BER performance and hence capacity