Relay Selection in Underlay Cognitive Radio Networks
In this paper, the authors investigate the performance of relay selection in an underlay cognitive radio system in the presence of Primary User (PU) interference. In particular, they consider a secondary multi-relay network operating in the Amplify-and-Forward (AF) mode and only the "Best" relay which satisfies an index of merit is selected. The proposed selection strategy takes into consideration the effect of PU interference, i.e., they assume that a secondary relay network is exposed to unwanted interference from a neighboring PU network. They derive a closed-form outage probability expression for the secondary multi-relay network and further present a thorough asymptotical diversity order analysis.