Asymptotic analysis of amplify-and-forward relaying in Nakagami-fading environments

Amplify-and-forward (AF) relaying strategies are studied for Nakagami-fading channels in an (N + 2)-terminal wireless cooperative system where a source terminal transmits information to a destination terminal with the assistance of N relay terminals. The asymptotic outage behavior is investigated in terms of coding and diversity gains for channel-state information (CSI)-assisted AF relaying and semi-blind AF relaying in various channel profiles. It is shown that semi-blind AF relaying system achieves strictly higher average SNRs. Further, when there exists fading severity difference between the source-to-relay and relay-to-destination links, both AF strategies achieve the same diversity gain whereas semi-blind AF achieves strictly lower coding.