Asymptotic Distortion Performance of Source-Channel Diversity Schemes over Relay Channels

Diversity techniques are an effective answer to the challenges presented by fading channels. This paper focuses on studying the performance of systems with diversity of three forms: source coding diversity, channel coding diversity, and user-cooperation diversity. To best reflect a focus on real-time multimedia communications, performance is measured through the distortion exponent, which measures the rate of decay of the end-to-end distortion at high SNRs. User-cooperation diversity takes the form of a relay channel implemented with amplify-and-forward processing at the relay. The results show that channel coding diversity provides the best performance, followed by source coding diversity. The results also show a tradeoff between the quality (resolution) of the source encoder and the amount of cooperation (number of relay nodes).