Abstract: Development of new wireless applications and services, spectrum resources are facing unprecedented demand. Currently, spectrum allotment is done by providing each new service with its own fixed frequency band. With each passing day most of these technologies are tending toward fully wireless mode. Spectrum scarcity is one of the huge challenges that the current wireless technologies is facing. As Most of the spectrum band is already assigned. It has become more difficult to incorporate the new technologies or expand the existing services. To address this challenge, cognitive radio has rising technology, which avoids the congestion in wireless communication by feat unused radio spectrum. In this paper one of the spectrum sensing method Energy detection is discussed and compare the ROC (Receiver Operating Characteristics) curve and probability of detection (Pd) versus SNR (Signal-to-noise Ratio) curve for Rayleigh channel using cubic , double-squaring and addition of squaring operations. The double-squaring operation show an improvement up to 0.3 times and addition of squaring operation show an improvement up to 0.7 times as compared to the cubic operation for Rayleigh channel.
Keywords: Cognitive Radio, Rayleigh channel, SNR, ROC.