High-SNR Analysis of Opportunistic Relaying Based on the Maximum Harmonic Mean Selection Criterion

In this letter, we consider a cooperative communication network over Rayleigh fading channels. We assume that the amplify-and-forward (AF) and the selection decode-and-forward (SDF) opportunistic relaying methods are used and that the relay with the largest harmonic mean of the source-relay channel gain and the relay-destination channel gain is selected for forwarding the message to the destination. We derive the high-SNR outage probabilities, which are then compared with the simulation results. We also compare our analytical results with the high-SNR outage probabilities found when the max–min criterion is used to select the opportunistic relay.