Cognitive Radio and Cooperation among the Primary and Secondary Users

In this paper, a two-hop cooperative cognitive radio network is investigated which is composed of two secondary users and one primary user. In the first hop, all transmitters broadcast their data to the relay network, simultaneously. However, in the second hop, forwarding the received data from the relay network to the destinations, takes place in two time slots. In order to have the maximum received SINR at each destination, a cooperative beamforming method is employed in the relay network. Moreover, through this method, the interference plus noise power imposed on the destinations is controlled. Finally, to investigate the efficiency of our work, simulation results are provided.