Wireless technology is embedded in our daily routine – laptops, cell phones, sensors – all are Wireless devices and use a finite amount of radio spectrum. As the number of devices increase, they compete for bandwidth and the service level provided to them is degraded. Moreover, traditional fixed spectrum allocation policy can no longer meet the needs and services of the wireless users. According to Federal Communications Commission (FCC), temporal and geographical variations in the utilization of the assigned spectrum range from 15% to 85% in current spectrum allocation policies. So, we need to find out ways to allow wireless devices to efficiently share the em waves. Cognitive Radio (Dynamic Spectrum Access) has been proposed as a potential solution for spectrum inefficiency problems. 1) To study and analyze the performance of energy detection based spectrum sensing technique and cyclic -prefix based spectrum sensing technique using ROC (Receiver Operating characteristics) curves. 2) To implement energy detection and cyclic prefix based spectrum sensing techniques on wireless channels in OFDM system.