Improved Spectrum Sensing Technique using Multiple Energy Detectors for Cognitive Radio Networks

Cognitive radio is an enabling technology to solve the spectrum scarcity problem in wireless communication. This is based on the concept of opportunistic spectrum access. Spectrum sensing is one of the most important functions in cognitive radio (CR) implementation. In this paper, we propose a multiple energy detectors (MED) based scheme with improved detection performance at low signal to noise ratio (SNR). We consider a framework of CR networks in which each CR node is equipped with MEDs and each energy detector with single antenna. An analytical model is developed for performance evaluation in terms of probability of false alarm Pf, and probability of detection Pd. Numerical results obtained in Rayleigh fading channel show that the proposed scheme performs better as compared to conventional energy detector (ED). The proposed scheme is further extended for cooperative detection, which further yield better detection performance. Optimal number of CR users involved in cooperative spectrum sensing is also investigated to reduce overheads and system complexity.