Shifted Successive Decode-and-Forward Relaying: Towards the Optimal Diversity-Multiplexing Tradeoff for a Four-Node Cooperative Network

In this paper, a novel cooperative diversity transmission protocol is proposed for a four-node network where a single-antenna source communicates with its intended N-antenna destination with the help of two K-antenna decode-and-forward (DF) relays. Without requiring complex coding strategies at the relays, a sufficiently strong or weak inter-relay channel, or destination-source feedback, the proposed shifted successive DF relaying (SSDFR) protocol asymptotically achieves the optimal diversity-multiplexing tradeoff performance the four-node network can provide.