International Journal of Computer Applications
A relay assisted cooperative beamforming technique can efficiently improve the spectral efficiency and can reduce the interference to primary users in cognitive underlay systems. The authors' objective is to reduce the total power cost of Secondary Users (SUs) while limiting the interference in the direction of Primary Users (PUs). K-mean algorithm which is a partition based clustering algorithm is used here as the clustering algorithm. While considering flexible cooperation as general scheme, they collectively optimize the clustering and the beamforming to lower the overall power consumption while fulfilling the secondary users quality of service and satisfying the primary users interference temperature limits.