1. 1 Adaptive Channel Estimation for MB-OFDM Systems under Interfering Environments Presented by 王欽洲 2006.06.30

2. 2 Outline System Descriptions Motivations The time redundancy properties TR Estimators Simulations Conclusions

3. 3 Outline System Descriptions Motivations The time redundancy properties TR Estimators Simulations Conclusions

4. 4 System description Channel h ( t) S/P P/S Insert pilot & FFT Add GI & P/S DAC Signal Mapper FFT S/P & remove GI ADC Signal Demapper Channel EQ Channel Estimator de-interleaver / viterbi decoder / de-scrambler scrambler / convolutional encoder / puncturer / interleaver TFC

5. 5 UWB preamble format Packet Sync Sequence 21 OFDM symbols Frame Sync Sequence 3 OFDM symbols Channel Est Sequence 6 OFDM symbols PS_0PS_1PS_20FS_0FS_1FS_2CE_0CE_1 CE_5

6. 6 Time Frequency Code Table TFC Number BAND_ID for TFC 1123123 2132132 3112233 4113322 5111111 6222222 7333333

7. 7 Outline System Descriptions Motivations The time redundancy properties TR Estimators Simulations Conclusions

8. 8 Scenarios of UWB preamble collisions(1/2) Case (a) Case (b) preamble interference

9. 9 Scenarios of UWB preamble collisions(2/2) Case (a) Case (b)

10. 10 Outline System Descriptions Motivations The time redundancy properties TR Estimators Simulations Conclusions

11. 11 The property exploited(1/3)

12. 12 The property exploited(2/3)

13. 13 The property exploited(3/3)

14. 14 Outline System Descriptions Motivations The time redundancy properties TR Estimators Simulations Conclusions

15. 15 Proposed estimator-TR estimator TR estimator –LSE –Linear Interpolation Combination Schemes –Equal Gain Combining –Maximum Ratio Combining –Select and Repeat Combining

16. 16 Equal Gain Combining(1/2) Case (a) Case (b) preamble interference noise 0.5

17. 17 Equal Gain Combining(2/2) Case (a) Case (b) 0.5

18. 18 Maximum Ratio Combining(1/2) Case (a) Case (b) preamble interference noise

19. 19 Maximum Ratio Combining(2/2) Case (a) Case (b)

20. 20 Select and Repeat Combining(1/2) Case (a) Case (b)

21. 21 Select and Repeat Combining(2/2) Case (a) Case (b)

22. 22 TREO estimator Time Redundancy Even Odd (TREO) –First symbol → even sub-carriers –Second symbol → odd sub-carriers

23. 23 Outline System Descriptions Motivations The time redundancy properties TR Estimators Simulations Conclusions

24. 24 Simulation environment & Criteria OFDM symbol with N=128. ZP length 32. UWB channel CM1 ~ CM4. 528M chip rate. UWB symbol with N=128. ZP length 32. UWB channel CM1 ~ CM4. 528M chip rate.

25. 25 Simulation result – one symbol ZP noise only

26. 26 Simulation result – one symbol ZP low SIR low SNR

27. 27 Simulation result – one symbol ZP low SIR high SNR

28. 28 Simulation result – one symbol ZP low SIR random

29. 29 Simulation result – one symbol ZP high SIR random

30. 30 Simulation result – UWB noise only

31. 31 Simulation result – UWB low SIR

32. 32 Simulation result – UWB high SIR

33. 33 Simulation result – UWB low SIR

34. 34 Simulation result – UWB high SIR

35. 35 Outline System Descriptions Motivations The time redundancy properties TR Estimators Simulations Conclusions

36. 36 Conclusions We can introduce time redundancy by frequency decimation and apply diversity combining. We can expect the improvement by TR estimator. TR estimator can also work well for other applications