Cognitive radio (CR) is a kind of wireless communication wherein a transceiver can intelligently sense the vacant and occupied communication channels and promptly move into vacant channels while staving off occupied ones. This enables the optimum use of available Radio-Frequency (RF) spectrum whereas avoiding the interference to other users. Cognitive radio is a key technology that came up with the solution of the problem of underutilization of radio frequency. To explore the capabilities and benefits of CR in better way, researchers now a days are interested in adaptive control paradigms...