Interference control in cognitive radio using joint beamforming and power optimization by applying artificial bee colony

We consider a cognitive radio scenario in which two networks share a licensed spectrum. Primary network is the legitimate network while cognitive radio network utilizes the underutilized frequency sub bands. For this scenario our focus is primarily on controlling the interference to the legitimate user and in addition, to minimize the interference between the secondary users while assuring quality service to secondary as well as primary user. For this one of the most favorable methods we have found is joint beamforming and power control. Main aspiration of this scheme is to minimize the transmission powers to trim down the interference plus to find out the apposite beamforming weights that help in reducing interference. We are presenting artificial bee colony algorithm to optimize this problem. We consider two scenarios. One is cooperative scenario, in which primary network cooperates with cognitive radio network to jointly optimize the power and beamforming weights and second in which there is no cooperation between the two and only cognitive radio optimizes its beam and power to control interference. While optimizing the solution for both the scenarios, we consider some constraints which are different for both scenarios.