Performance Evaluation of Secured Co-operative Networks using Diversity Combining Techniques

The Spectrum scarcity is a major issue faced in wireless communication nowadays. To mitigate this problem, cognitive radio technology is the solution since utilizes the spectrum in an adaptable manner. The security of the cognitive radio was achieved by implementing relay selection scheme in the Physical layer. In underlay cognitive network due to the coexistence of primary user and secondary user, The Secondary user must in turn guard the primary user from the Eavesdropper. Here Cooperative diversity combining is incorporated with relay nodes in multipath fading environment to improve the secrecy performance in terms of Secrecy Outage Probability and Bit Error Rate (BER). The secrecy rate of the cognitive radio network has been analyzed with and without relay. It is obvious that Maximal ratio combining outperforms Selection combining scheme since the signals from each channel are added together. From the numerical results it is evident that BER comes down to 10−3 which is the required standard value for the wireless fading environment. Also the Outage probability with Amplify and Forward (AF) plus direct transmission gives the best performance compared to direct transmission.