1. Cooperative Communication in Wireless Networks Aria Nosratinia, University of Texas, Dallas, Todd E. Hunter, Nortel Networks Ahmadreza Hedayat, University of Texas, Dallas Speaker ： Ching-Chung Lin IEEE Communications Magazine October 2004

2. Outline Introduction Assumption Cooperative Communication Performance Conclusion

3. Introduction The mobile wireless channel suffers from fading  signal attenuation can vary significantly Transmitting independent copies of the signal from different location  generates spatial diversity  effectively combat fading

4. A B C

5. Assumption One antenna Each host have one partner  may be assigned mutually by the base station Each host is a both a user and a relay One cooperator forward “overheard” information

6. Cooperative Communication Amplify and forward Decode and forward Coded cooperation

7. Cooperative Communication Amplify and forward Decode and forward Coded cooperation

8. Amplify and forward Assumption  Each user receives a noisy version of the signal transmitted by its partner  The base station knows the interuser channel coefficients to do optimal decoding

9. A B C User relaydestination

10. Cooperative Communication Amplify and forward Decode and forward Coded cooperation

11. Decode an d forward Assumption  each user transmits its own bits detects the other user’s second bit

12. Decode an d forward symbol definition  each user has its own spreading code C1(t) C2(t)  two user’s data bits  Signal amplitudes i ： transmission interval j ： power level ex ：

13. Decode an d forward

16. J. N. Laneman, G. W. Wornell, and D. N. C. Tse, “An Efficient Protocol for Realizing Cooperative Diversity in Wireless Networks,” Proc. IEEE ISIT, Washington, DC,June 2001  When the SNR is high, user enter into cooperative mode.  When the SNR is low, user enter into noncooperative mode.

17. Cooperative Communication Amplify and forward Decode and forward Coded cooperation

18. each user  decode the transmission of its partner  data is encoded into a codeword N bits = N1 + N2

19. A B C N1 bits : userA ’ s data Frame1 N2 bits : userA ’ s data Frame2 N1 bits : userB ’ s data Frame1 N2 bits : userB ’ s data Frame2

20. A B C N1 bits : userA ’ s data Frame1 N1 bits : userB ’ s data Frame1

21. Performance rate-compatible punctured convolutional (RCPC) codes

22. User 1 User 2 destination SNR=X

23. Performance

24. User 1 User 2 destination SNR=X+10 SNR=X

25. Performance

26. conclusion Results to date are indicative of a promising future for cooperative communication.

27. Thank You

28. 英 文： Block Error Rate (BKER, BLER) 台 灣： 塊誤率 大 陸： N/A 修訂時間： 2000/9/13 字組錯誤率，數據組出錯率，信息組差錯率錯誤地接 收方塊 (Blocks) 的數目和送出方塊總數目的比率，來 衡量塊處理效果。