Beamforming and power control for interference reduction in wireless communications using particle swarm optimization

We consider joint beamforming (BF) and power control to minimize cochannel interference in a CDMA wireless uplink, where an antenna array of different geometries receives from single-antenna wireless users. The problem is to find the optimum beamforming weight vector and the minimum transmission power of each terminal such that the quality of service (QoS) requirements of the users are fulfilled and the so-called near–far effect is alleviated. This will increase the channel capacity and further prolongs the battery lives of the mobile terminals. The particle swarm optimization method is used to determine the optimum beamforming weight vector and the minimum transmission power of each terminal. Uniform linear and circular array geometries are considered, with and without correlated shadow fading. Simulation results illustrate the advantage of using BF jointly with power control and the robustness of the optimization technique used.