Channel assignment in cognitive radio networks: comparison and analysis

Traditional wireless networks are characterized by fixed spectrum assignment policy where a new approach is cognitive radio networks. In a cognitive radio paradigm we opportunistically sense the spectrum and utilize the part of the spectrum which is available. However with the new paradigm of cognitive radio wireless networks we can use spectrum depending upon the licensed user spectrum usage. To utilize the white spaces (the band of frequency, which is not used by a licensed user at particular instance, space) we need to impart cognition to cognitive nodes. In the paradigm of cognitive radio networks the heterogeneity plays the main role. In this survey paper we explained different approaches to tackle the channel assignment in wireless as well in cognitive radio networks. Due to the heterogeneous characteristics of spectrum in cognitive radio networks, efficient channel assignment becomes a challenge. This is because these channels have different ranges, data rates and interference parameter in time and space. We discuss different approaches that cater for the channel assignment problem.