JCS_V3_N3_RP2 Yamini Verma Neelam Dewangan Journal on Communication Engineering and Systems 2277-5242 3 3 7 13 Cognitive Radio, PU, Spectrum Sensing, Co-Operative Sensing, SNR (Signal - to - Noise Ratio), QoS (Quality of Service) One of the emerging techniques in wireless communication is cognitive radio which is used for the efficient utilization of radio frequency spectrum. One important requirement of cognitive radio is spectrum sensing. In this paper, various types of spectrum sensing techniques are mentioned. Cooperative sensing seemed to be the best method among all spectrum sensing techniques applied to overcome the problem of detection and false alarm associated by using single user. This paper studies the cooperative spectrum sensing scheme as means of optimizing the sensing performance in Rayleigh channels. Plot of SNR versus probability of detection for different values of false alarm is shown in this paper. All this output is achieved using MATLAB. May - July 2014 Copyright © 2014 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=3177