International Journal of Soft Computing and Engineering (IJSCE)
The wireless traffic is increasing in an unparalleled way, which causes radio spectrum shortage. The fixed spectrum assignment policy makes this problem more critical. Cognitive radio is one answer to spectrum scarcity problem. In cognitive radio, the licensed bands are opportunistically accessed when primary user is absent. The first step to a cognitive radio network is the spectrum sensing. An efficient and fast spectrum sensing can make cognitive radio more useful practically. In this paper, the authors discuss several spectrum sensing techniques used in cognitive radio.