Download
introduction to smart antenna n.
Skip this Video
Loading SlideShow in 5 Seconds..
Introduction to Smart Antenna PowerPoint Presentation
Download Presentation
Introduction to Smart Antenna

Introduction to Smart Antenna

306 Vues Download Presentation
Télécharger la présentation

Introduction to Smart Antenna

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Introduction to Smart Antenna 指導老師:黃文傑 博士 姓 名: 吳 濟 廷 2003.11.07 無線通訊實驗室

  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

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

  6. Why Smart Antenna • Reduction of transmitter power • Reduction of delay spread • Accurate user position estimation Fixed cell shape Dynamic cell shape

  7. 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

  8. Smart Antenna LoS MP Mobile 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

  9. Smart Antenna Interference LoS MP Mobile 2 Mobile 1 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

  10. How Smart Antenna works • Wave propagation • Parametric data model • Uniform Linear Array geometry • Uniform Circular Array geometry

  11. Wave propagation • From Maxwell’s equations • Homogeneous wave equation • f satisfy homogeneous wave equation

  12. Where B is the bandwidth of s(t)

  13. Parametric data model Base-band signal Array propagation vector

  14. Uniform Linear Array geometry

  15. Base-band signal

  16. Uniform Circular Array geometry

  17. 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