Joint Relay Selection and Spectrum Allocation Scheme in Cooperative Relay Networks

Joint relay selection and spectrum allocation scheme with multiple source-destination pairs and multiple potential relays in cooperative relay networks is proposed in this paper. In cooperative relay networks, the selected relay nodes and spectrum resource allocated to each source-destination pair have great impact on the system performance. It is an optimization problem for which relay nodes are selected and which spectrum resources are assigned. The exhaustive search can solve this problem but the complexity will increase factorially with the network size (i.e., the number of source-destination pairs and the number of relays in the network) and exponentially with the number of available spectrum resources. This paper proposes a novel quantum particle swarm optimization (QPSO) based relay selection and spectrum allocation scheme which can maximize three definitions of system throughput but has less computational complexity. Simulation results show that QPSO based scheme has the ability to find global optimal solution compared with other schemes in the literature.