Performance improvement of secondary user transmission in cognitive radio networks

In this paper, we present a method for relay selection and power optimization under a cooperative transmission scenario for cognitive radio networks. While ensuring the quality of service (QoS) of primary transmissions, our aim is to improve the performance of secondary transmissions. The best relay selection and single relay selection cooperative communication methods are employed. Power optimization is achieved to ensure optimal power distribution in both methods. Error performance is investigated for cooperative communication and compared with that of the cognitive network. Simulation results show that we attain an improved system throughput in cognitive radio networks.