In present scenario, the increase in number of users has led to spectrum scarcity. To overcome this problem, Cognitive Radio is an apparent technology. Cognitive Radio allows a group of users to identify the vacant slots and access the available resources using different spectrum management functions. The key feature of  cognitive radio is the spectrum sensing. In Cognitive Radio, the spectrum sensing is performed to locate unused spectrum segments. Thus keeping in view of efficient utilization of the spectrum, it is necessary to investigate the Spectrum Sensing and Spectrum Sharing techniques. Energy detection technique is used in this paper within cooperative sensing to analyze the results. The main motive is to enhance the performance of the system. At last, there are simulation results showing the performance of AWGN and Rayleigh channels at different SNR’s using different modulation techniques to improve the overall detectability. A graph is shown that compares modulation techniques in AWGN environment.