An efficient relay assignment scheme for multiuser cognitive radio networks with discrete power control

In this paper, we present a binary particle swarm optimization (BPSO)-based low-complexity interference aware relay assignment scheme for multiple-user cognitive radio networks with discrete power control. We consider a network of cognitive radio nodes comprising single source, multiple relays and multiple destinations. For this system, we formulate an optimization problem to allocate power to source and relays and assign the relays to the destinations. The optimization problem is formulated as a mixed integer nonlinear program. Then, we show that the formulation can be reduced into a simpler integer programming problem. Then, we propose a BPSO-based relay assignment scheme to attain a good suboptimal solution to this integer programming problem. The proposed scheme has low computational complexity, and simulation results show that its performance is close to the optimal exhaustive search algorithm.