QBCO and NSQBCO Based Multi-User Single-Relay Selection Scheme in Cooperative Relay Networks

In cooperative relay networks with multiple users and multiple potential relays, which relay nodes are selected has great impact on the system performance. It is an optimization problem for selecting suitable relay nodes. The exhaustive search can solve this problem but the complexity will increase factorially with the network size, i.e., the number of users and the number of relays in the network. In this paper, we formulate both single-objective and multi-objective relay selection problems. For single-objective relay selection problem, only one system objective is considered. A novel quantum bee colony optimization (QBCO) based relay selection scheme is proposed. For multiobjective relay selection problem, two contradictive objectives are considered simultaneously. A novel non-dominated sorting quantum bee colony optimization (NSQBCO) based relay selection scheme is proposed. Simulation results show that the proposed relay selection schemes have the ability to find global optimal solution but have less computational complexity compared with exhaustive search scheme.