Performance improvement of energy detector in cognitive radio using SECp diversity combining technique over fading channel

Abstract

In this paper, performance of energy detector is analysed over Rayleigh fading environment using different diversity combining techniques. The channel is considered as Independent and Identically Distributed (IID). The closed form expressions for probability of detection using Switch and Stay Combining (SSC) as well as switch and examine combining using post examining selection (SECp) are derived. The performance is compared using the curves of probability of detection for different Signal to Noise Ratio (SNR). Probability of false alarm versus probability of misdetection curves is also compared. These curves are called complementary Receiver Operating Characteristics (ROC) curves. For dual diversity system, SECp is a modified form of SSC. Unlike SSC, when all the paths are tested and none of them has an acceptable SNR, the SECp combiner selects the path having highest SNR. So energy detector's detection performance in a dual diversity system is improved using SECp which is analysed here.