A Novel Relay Selection Algorithm for Relaying Networks

Cooperative diversity has been recently proposed as a way to form virtual antenna arrays that provide dramatic gains in slow fading wireless environments. In a multiple-relay network, the opportunistic relay selection scheme has been shown to outperform any other strategy that involves the conventional all-participate scheme. The opportunistic relay selection scheme generally supposes the existence of a centralized entity to find out the best relay node. Unfortunately, when the number of relay nodes is increased, the resulting enormous overhead renders the centralized-based relay selection method to be impractical. Accordingly, we develop in this paper a decentralized relay selection algorithm, where each relay node decides to relay or keep silent according to its own instantaneous channel gain and a predefined threshold. Specifically, the proposed method can be considered as a process to eliminate the relay having the worse channel gain at each stage until the best relay node is determined. Simulation results illustrate that the proposed scheme has almost the same performance as that of the opportunistic relay selection method.