EURASIP Journal on Wireless Communications and Networking 
Volume 2006 (2006), Article ID 17862, 8 pages
doi:10.1155/WCN/2006/17862

Nonregenerative Dual-Hop Cooperative Links with Selection Diversity

Theodoros A. Tsiftsis,1 George K. Karagiannidis,2 P. Takis Mathiopoulos,3 and Stavros A. Kotsopoulos1

 1Department of Electrical & Computer Engineering, University of Patras, Rion, Patras 26500, Greece
2Department of Electrical & Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki 54 124, Greece
3Institute for Space Applications and Remote Sensing (ISARS), National Observatory of Athens, Metaxa & Vas. Pavlou Street, Palaia Penteli, Athens 152 36, Greece
Received 1 November 2005; Revised 11 March 2006; Accepted 17 May 2006

Abstract

The end-to-end performance of dual-hop cooperative diversity systems equipped with nonregenerative relays and a selection combining receiver at the destination terminal over independent and nonidentical Nakagami-m fading channels is studied. Closed-form expressions for the cumulative distribution function and the probability density function of the end-to-end signal-to-noise ratio (SNR) are presented, while analytical formulae are derived for the moments and the moment generating function. Using these statistical results, closed-form expressions for the outage probability are presented for both channel state information and fixed gain relays. Furthermore, for the case of fixed gain relay, the average end-to-end SNR, the amount of fading, and the average bit error rate can be numerically evaluated. The proposed mathematical analysis is complemented by numerical examples, including the effects on the overall performance of the SNRs unbalancing as well as the fading severity.