Performance Analysis for Amplify-and-forward Opportunistic Relaying with Quality Based Channel State Reporting

In this paper, we first provide the closed-form outage probability of opportunistic single relay selection in amplify-and-forward (AF) relaying under the arbitrary distributed Rayleigh fading channels. To select the best relay, information exchanging is essential. However, too many information exchanges may rather impair the system performance due to causing congestion in feedback link as well as increasing overhead. In this paper, we will investigate the performances for the AF relaying through the best relay with quality based channel state reporting (QBR) which is one of the widely accepted ones to reduce the feedback amount. We analyze the feedback amount, average capacity, and outage probability for QBR based selection, which are used to make the comparison to the full feedback scheme. Numerical results show that the QBR scheme can reduce the feedback amount remarkably, but achieve as same capacity as the full feedback scheme when the number of relays K is sufficiently large. For the outage performance, QBR scheme induces no performance loss when the threshold is same as the target signal-to-noise ratio (SNR).