Maximum Likelihood Detection for Detect-and-Forward Relay Channels

Azlan Abd Aziz, Yasunori Iwanami

.

DOI: 10.4236/ijcns.2011.42011                

Abstract

This paper introduces a simple combining technique for cooperative relay scheme which is based on a Detect-and-Forward (DEF) relay protocol. Cooperative relay schemes have been introduced in earlier works but most of them ignore the quality of the source-relay (S-R) channel in the detection at the destination, although this channel can contribute heavily to the performance of cooperation schemes. For optimal detection, the destination has to account all possible error events at the relay as well. Here we present a Maximum Likelihood criterion (ML) at the destination which considers closed-form expressions for each symbol error rate (SER) to facilitate the detection. Computer simulations show that significant diversity gain and Packet Error Rate (PER) performance can be achieved by the proposed scheme with good tolerance to propagation errors from noisy relays. In fact, diversity gain is increased with additional relay nodes. We compare this scheme against the baseline Cooperative-Maximum Ratio Combining (C-MRC).

Keywords

Cooperative Relay, Detect-and-Forward, Maximum-Likelihood Criterion Detection

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	J. Laneman, D. Tse and G. Wornell, “Cooperative Diversity in Wireless Networks: Efficient Protocols and Outage Behaviour,” IEEE Transactions on Information Theory, Vol. 50, No. 12, December 2004, pp. 3062-3080. doi:10.1109/TIT.2004.838089
[2]	A. Sendonaris, E. Erkip and B. Aazhang, “User Cooperation Diversity Part I and Part II,” IEEE Transactions on Communications, Vol. 51, No. 11, November 2003, pp. 1927-1948. doi:10.1109/TCOMM.2003.818096
[3]	A. Nosratinia and T. E. Hunter, “Diversity through Coded Cooperation,” IEEE Transactions on Wireless Communications, Vol. 5, No. 2, February 2006, pp. 283-289. doi:10.1109/TWC.2006.1611050
[4]	D. Chen and J. N. Laneman, “Modulation and Demodulation for Cooperative Diversity in Wireless Systems,” IEEE Transactions on Wireless Communications, Vol. 5, No. 7, July 2006, pp. 1785-1794. doi:10.1109/TWC.2006.1673090
[5]	A. A. Aziz, Y. Iwanami and E. Okamoto, “On the Improvement of Maximum Likelihood in Multiple Relay Systems,” Proceedings of IEEE Wireless Communications & Networking Conference, Sydney, 18-21 April 2010, pp. 1-6. doi:10.1109/WCNC.2010.5506662
[6]	T. Wang, A. Cano, G. Giannakis and N. Laneman, “High Performance Cooperative Demodulation with Decode-and-Forward Relays,” IEEE Transactions on Wireless Communications, Vol. 55, No. 7, July 2007, pp. 1427-1438.
[7]	B. Djeumou, S. Lasaulce and A. G. Klein “Combining Decoded and Forwarded Signals in Gaussian Cooperative Channels,” Proceedings of IEEE International Symposium on Signal Processing and Information Technology, Vancouver, 27-30 August 2006, pp. 622-627.
[8]	M. R. Souryal and H. You, “Diversity Performance of a Practical Non-Coherent Detect-and-Forward Receiver,” Proceedings of IEEE Global Telecommunications Conference, New Orleans, 30 November-4 December 2008, pp. 1-6.
[9]	M. Benjillali and L. Szczecinski, “A Simple Detect-and-Forward Scheme in Fading Channels,” IEEE Communications Letters, Vol. 13, No. 5, May 2009, pp. 309-311. doi:10.1109/LCOMM.2009.090139
[10]	M. N. Khormuji and E. G. Larsson, “Receiver Design for Wireless Relay Channels with Regenerative Relays,” Proceedings of IEEE International Conference on Communications, Glasgow, 24-28 June 2007, pp. 4034-4039.
[11]	J. P. K. Chu, R. S. Adve and A. W. Eckford, “Using the Bhattacharyya Parameter for Design and Analysis of Cooperative Wireless Systems,” IEEE Transactions on Wireless Communications, Vol. 8, No. 3, March 2009, pp. 1384-1395. doi:10.1109/TWC.2008.080071
[12]	K. Lee and L. Hanzo, “MIMO-Assisted Hard versus Soft Decoding-and-Forwarding for Network Coding Aided Relaying Systems,” IEEE Transactions on Wireless Communications, Vol. 8, No. 1, January 2009, pp. 376-385. doi:10.1109/T-WC.2009.080048
[13]	X. Hu, M. Benjillali and L. Szczecinski. “Bit Error Rate for Rectangular QAM with Arbitrary Constellation Mapping in Nakagami-m Channels,” Wiley Journal on Wireless Communications and Mobile Computing, Vol. 8, No. 1, 2008, pp. 93-99. doi:10.1002/wcm.437
[14]	M. S. Alouini and A. J. Goldsmith, “A Unified Approach for Calculating Error Rates of Linearly Modulated Signals over Generalized Fading Channels,” IEEE Transactions on Communications, Vol. 47, No. 9, September 1999, pp. 1324-1334. doi:10.1109/26.789668