Performance Analysis of Several Relay Node Selection Schemes for Cooperative Communications

This paper considers a cooperative wireless network where a set of nodes cooperate to relay in parallel the information from the source node to the destination node employing a decode-and-forward approach. The proposed cooperation takes place in two phases. During the first phase, the source node broadcasts signals to the relay nodes and the destination node. During the second phase, some relay nodes are selected to forward the decoded signals to the destination node in light of the given relay node selection scheme. Within the same cooperative system framework, outage probability and diversity-multiplexing tradeoff (DMT) expressions are developed for several relay node selection schemes named as random relay node selection (RRS), best relay node selection (BRS), and all relay nodes selection (ARS), respectively, so as to measure and compare their corresponding performance. Numerical results demonstrate that both of ARS and BRS can achieve significant performance gains over RRS. Furthermore, ARS can also offer some performance gains over BRS at the cost of increasing some computational complexity.