International Journal of Engineering and Innovative Technology (IJEIT)
The limited available spectrum and the inefficiency in the spectrum usage results in a new communication technology, referred to as cognitive radio networks. Cognitive radio a promising technology which provides a novel way to improve utilization efficiency of available electromagnetic spectrum. Spectrum sensing is a key function of cognitive radio which helps to detect the spectrum holes (underutilized bands of the spectrum) providing high spectral resolution capability to prevent the harmful interference with licensed users and identify the available spectrum for improving the spectrum's utilization. Different spectrum sensing techniques including narrowband and wideband spectrum, single and cooperative spectrum sensing techniques are discussed. Challenges of spectrum sensing process are presented. Blind detector techniques and robust sensing algorithms are also explained and discussed in this paper.