Performance Evaluation of Energy Detector in Cognitive Radio System

The most popular technique to detect unused license spectrum in Cognitive Radio (CR) is Energy Detector (ED). It is a blind detector that prior knowledge of primary user signals for detection is not required. This paper studies detection performance of unused spectrum under Rayleigh fading and additive white Gaussian noise (AWGN). We evaluate detection performance as a function of probability of false detection (Pf) and detector threshold (lambda). Performance of energy detector under Rayleigh fading is compared with energy detection under AWGN. The derived results show that at a certain values, the performance of detection under Rayleigh fading outperforms detection under AWGN.