Cross-Layer Performance Study of Cooperative Diversity System With ARQ

In this paper, a cross-layer design of a wireless communication system is proposed by considering a quadrature signaling (QS)-based cooperative diversity (CD) system employing truncated stop-and-wait automatic repeat request (ARQ) for error control. The proposed CD-ARQ scheme employs selection relaying at the partner, and all the transmission channels are assumed to exhibit Nakagami-m fading. To analyze the cross-layer performance of the proposed scheme, a Markov model is developed by capturing the effects of correlated transmission errors of the Nakagami-m fading cooperative channels. Based on the analysis, the effective cooperative channel of QS-CD-ARQ is uncorrelated when the normalized Doppler shift of at least one of the user-to-destination channels is higher than 0.2. Performance metrics (e.g., channel efficiency, packet loss rate, throughput, average delay, and jitter) are taken into account in the study. Our numerical results show that the QS-CD-ARQ scheme outperforms both an incremental-relaying-based CD system and a non-cooperative system if the average of the received signal is higher than the receiver sensitivity and if the channel between users is better than the direct transmission channel. In addition, QS-CD-ARQ provides the lowest packet loss rate with the lowest delay among all the schemes for any number of maximum retry limits. Moreover, compared with a scheme that employs incremental relaying, the proposed QS-CD-ARQ scheme is less complex to implement.