Energy detection analysis of hybrid cooperative relaying mode in cognitive radio network

In this study, the performance of a cooperative multi-antenna cognitive relay (CR) based system that consists of one primary user (PU) and one cognitive coordinator (CC) is analyzed. The energy detector is implemented at cognitive coordinator to make final decision on PU by using cognitive multi-antenna relay. The cognitive multi-antenna relay employs selection combining (SC) from the signal received from PU through multi-antenna paths, while CC employs maximal ration combining (MRC) and selection combining (SC) of two path signals, one from direct-path PU and another from CR path. To analyze this system, initially two methods viz., CR using two cooperative relaying modes Amplify-and-Forward (AF) and Decode-and-Forward (DF) have been used. In the proposed cooperative relaying mode, CR chooses adaptively either Decode- and-Forward or Amplify-and-Forward (hybrid) based on the received SNR of cooperative relaying modes DF and AF. The analysis for probability of detection and probability of false alarm are evaluated for proposed hybrid mode cooperative spectrum sensing.