Two stage spectrum sensing for Cognitive Radio using CMME

Spectrum sensing is fundamental functionality in Cognitive Radio (CR) to identify spectral white spaces for opportunistic communication. Around last decade thorough study of spectrum sensing suggests that traditional energy detection (ED) performance is better and fast at high SNR and worst in low SNR, whereas cyclostationary and Eigenvalue based methods perform better at low SNR, but implementation complexity is high. As suggested in IEEE 802.22 standard for CR, we propose in this paper, novel two stage spectrum sensing based on energy detection as coarse sensing first stage and combination of maximum-minimum eigen value based detection technique (CMME) as fine sensing second stage. The dual stage threshold parameter is designed to maximize the probability of detection for given constraints on the probability of false alarm. Comparative analysis of single stage ED, Combination of maximum-minimum eigen value based detection (CMME), Cyclostationary detection technique (CSD), Combination of Cyclostationary detection and ED detection and Combination of CMME and ED detection is performed using probability detection (P_d) versus SNR curve.