Performance evolution of energy detection spectrum sensing technique used in cognitive radio

With the development in wireless communication in last few years, the problem of bandwidth shortage has become more noticeable. The studies made by FCC (Federal Communications Commission) indicated that large portion of the spectrum lies vacant most of the time and that portion is the licensed spectrum; which is utilized by licensed users only. So, to solve this problem of spectrum under-utilization, FCC (Federal Communications Commission) allowed secondary users to utilize the licensed band when it is not in use and called it as Cognitive Radio. To solve the spectrum overcrowding problem, cognitive radio (CR) has developed as a leading technology because it can intelligently sense a vacant spectrum and allocate it to the secondary users without interfering to authorized users. To sense the presence of primary users, spectrum sensing techniques are used. This thesis discusses the conventional energy detection method and proposed improved energy detection method using cubing operation and double-squaring operation. Mathematical Description of energy detection based spectrum sensing techniques is also illustrated for fading channels. According to the simulation presented in this thesis, an improvement of up to 1.3 times for AWGN Channel and up to 0.5 times for Rayleigh channel has been achieved, as the operation is changed from squaring operation to cubing operation in an energy detector and an improvement of up to 2 times for AWGN Channel and up to 0.7 times for Rayleigh Channel has been achieved as the operation changed from squaring operation to double-squaring operation in an energy detector.