Average capacity performance of opportunistic relay selection with outdated CSI

The authors investigate the effect of feedback delay on the average capacity of a decode-and-forward cooperative network with relay selection. In particular, a multi-relay cooperative scenario is considered, where the best relay is selected from a subset of relays that are able to decode the source information correctly. In this selection scenario, the authors assume that the destination terminal estimates the relay-to-destination (R→D) channel-state-information perfectly and sends the index of the best relay to the relay terminals via a delayed feedback link. The authors investigate the performance of the considered scenario in terms of average capacity. Simulation results are presented to corroborate the analytical results.