Garima MaaM, Mobile Com

1. May 28-June1, 2001 R. Z. Ziemer, Colorado Springs, CO Spread spectrum

2. I . History of Spread Spectrum II. Spread Spectrum System Model III. Spread Spectrum Classification IV. Spread Spectrum Techniques Outline

7. System Model: Spread Spectrum Transmission

9. Spread Spectrum Classification

11. Direct Sequence Spread Spectrum Example May 28-June1, 2001 R. Z. Ziemer, Colorado Springs, CO

12. Direct Sequence Spread Spectrum: Transmission Technique

13. Direct Sequence Spread Spectrum Transmitter May 28-June1, 2001 R. Z. Ziemer, Colorado Springs, CO

14. Direct Sequence Spread Spectrum Receiver May 28-June1, 2001 R. Z. Ziemer, Colorado Springs, CO

15. Direct Sequence Spread Spectrum Using BPSK Example May 28-June1, 2001 R. Z. Ziemer, Colorado Springs, CO

16. Approximate Spectrum of DSSS Signal May 28-June1, 2001 R. Z. Ziemer, Colorado Springs, CO

18. Frequency Hopping Spread Spectrum (FHSS) May 28-June1, 2001 R. Z. Ziemer, Colorado Springs, CO

19. Frequency selection in FHSS May 28-June1, 2001 R. Z. Ziemer, Colorado Springs, CO

20. FHSS cycles May 28-June1, 2001 R. Z. Ziemer, Colorado Springs, CO

21. Frequency Hopping Spread Spectrum

22. Bandwidth sharing May 28-June1, 2001 R. Z. Ziemer, Colorado Springs, CO

24. Comparison of different Spread Spectrum Techniques SS Technique advantage disadvantage Direct Sequence 􀂉 best behavior in multi path rejection 􀂉 no synchronization 􀂉 simple implementation 􀂉 difficult to detect 􀂉 near far effect 􀂉 coherent bandwidth Frequency Hopper 􀂉 no need for coherent bandwidth 􀂉 less affected by the near far effect 􀂉 complex hardware 􀂉 error correction needed Time Hopper 􀂉 high bandwidth efficiency 􀂉 less complex hardware 􀂉 less affected by the near far effect 􀂉 error correction needed

25. The Idea In MCM , we split the data in to different streams and transmit using separate Sub Carriers.

26. DS-CDMA Figure: The Principle of DS-CDMA

28. Thank You