Date Added: Aug 2012
In this paper one of the most important cognitive radio task i.e. spectrum sensing is discussed. Cognitive radio is an intelligent wireless communication technology in order to increase the spectrum efficiency. Increasing efficiency of the spectrum usage is an urgent need as an intrinsic result of the increasing demand for higher data rates, better quality of services and higher capacity. Spectrum sensing and awareness are challenging requirements in Cognitive Radio (CR). To adequately adapt to the changing radio environment, it is necessary for the CR to detect the presence and classify the on-the-air signals. The wireless industry has shown great interest in Orthogonal Frequency Division Multiplexing (OFDM) technology.