Abstract: The rapid growth in wireless communication systems has made the problem of under utilization of spectrum. To solve this problem the concept of cognitive radio (CR) emerged, the main goal of which is to provide adaptability to wireless transmission through dynamic spectrum access (DSA) so that the utilization of the frequency spectrum can be enhanced without losing the bene?ts associated with spectrum allocation. To sense existence of licensed user, Energy Detection based spectrum sensing technique is used over different wireless fading channels. In the energy detection approach, the radio-frequency (RF) energy in the channel or the received signal strength indicator is measured to determine whether the channel is idle or not. This paper gives the primitive study and performance analysis of energy detection based spectrum sensing technique. Performance is done under three different fading channels i.e. Rayleigh, Nakagami and Rician. Probability of detection and Probability of missed detection vs. probability of false alarm for all different channels has been calculated and also simulation comparison among different wireless fading channels is presented.

Keywords: Cognitive Radio , Energy Detection, Fading Channels, Spectrum Sensing, Pd, Pfa, Pmd, nakagami,rayleigh, rician.