Performance analysis of ARQ cooperative diversity system with multiple two-hop relays over Rayleigh fading channels

Cooperative communication systems can exploit spatial diversity by opportunistically choosing relays to forward information to the destination. In this paper, we investigate the statistical performance analysis of a general cross-layer automatic repeat request cooperative diversity (ACD) system by focusing on the scenario in which decode-and-forward relaying protocol and multiple two-hop relays are employed over Rayleigh fading channel environments. To obtain the theoretical closed-form formulas for end-to-end performance parameters, we develop a time division multiple access (TDMA)-based absorbing Markov model to help find all possible transition probabilities of each transmission process. Based on this proposed model and statistical analysis, we derive two tight closed-form expressions in terms of end-to-end packet delivery failure probability and end-to-end packet delivery delay distribution. In addition, an optimal power allocation scheme under a tight power constraint for the ACD system is proposed for further enhancing the symbol error rate (SER) performance, which outperforms the equal power allocation scheme obviously. Simulation results by Monte Carlo simulations demonstrate the correctness of our analysis eventually. (C) 2013 Elsevier Ltd. All rights reserved.