Optimization of the Relay Selection Scheme in Cooperative Retransmission Networks
While the benefits of cooperative diversity have been well studied in the literature, cooperative MAC protocol design has attracted more and more attention recently. In single-relay Cooperative Automatic Repeat reQuest (C-ARQ) protocol, the best relay node is selected in a distributed manner by relays using different backoff time before packet retransmission. However, this relay selection scheme does not work efficiently in a dense network scenario, due to high collision probability among different contending relays. In this paper, the authors propose an optimized relay selection scheme to maximize the system throughput by reducing the collision probability. The performance improvement in terms of throughput and packet delivery ratio by the proposed optimal relay selection scheme is verified by simulations.