Static hybrid Amplify-Decode and Forward Cooperative ARQ with opportunistic relaying

In this paper, we propose an hybrid Amplify-Decode and Forward (AF-DF) approach for cooperative Automatic Repeat reQuest (ARQ) protocols with opportunistic relaying. In the proposed scheme, relay operating mode was fixed with respect to the relay location. When a relay is close to source, it can operate in AF mode. Otherwise, relay operates in DF mode. With opportunistic relaying, the node that offers the high instantaneous Signal to Noise Ratio (SNR) of the relaying link retransmits the packet. This node is selected among the source, all AF relays and DF relays that have correctly decoded the transmitted packet. We evaluate the system performance in terms of average number of transmissions and throughput efficiency. Finally, simulation results are provided to validate our analysis.