Delays analysis of Cooperative truncated HARQ with opportunistic relaying and noisy feedback

In this paper, we evaluate the delay experienced by Poisson arriving packets for Cooperative truncated HARQ with opportunistic relaying in the presence of a noisy feedback channel. We derive the theoretical expressions of the expected waiting time and the packet´s sojourn time in the queue of truncated opportunistic cooperativeARQ and Hybrid ARQ I, with and without Packet Combining (PC), and Hybrid ARQ II with Code Combining (CC). The analysis is valid for any number of relays for both Amplify and Forward (AF) and Decode and Forward (DF) relaying strategies and Nakagami-m fading channels. The results indicate a significant improvement of packet delivery delays when compared to the absence of cooperation. Besides, we show that the effects of the noisy feedback can be reduced by coding the ACK message.