Comparative study of Narrowband and Wideband Opportunistic Spectrum Access Techniques

The radio spectrum is a limited natural resource which is precious due to the drastic growth in the wireless communication. The static allocation of the spectrum has led to an underutilization of the spectrum. Cognitive radio is the promising technology for the dynamic allocation of the spectrum which improves the spectrum utilization. In cognitive radio, an unlicensed (secondary) user can opportunistically access the spectrum when the licensed (primary) user is not transmitting, without causing any harmful interference to the primary user's signal. Spectrum sensing is the key element of cognitive radio, which provides the crucial information regarding the status of the spectrum. The spectrum sensing algorithms aims at detecting whether the primary user is transmitting over the spectrum or the spectrum is empty. Based on the results of the spectrum sensing the secondary user can opportunistically access the spectrum when the spectrum in empty. In this paper, a brief survey of narrow band and wide band spectrum sensing techniques have been discussed.