Date Added: Nov 2011
The limited available spectrum and the inefficiency in the spectrum usage necessitate a new communication technology, referred to as Cognitive Radio (CR) networks. The key characteristic of CR system is that it senses the electromagnetic environment to adapt their operation and dynamically vary its radio operating parameters. A cognitive radio must detect the presence of primary user to avoid interference. Spectrum sensing helps to detect the spectrum holes (unutilized bands of the spectrum) providing high spectral resolution capability. Different spectrum sensing techniques for cognitive radio are discussed in this paper.