Publication

Abstract : Presently the wireless networks are operated on the basis of fixed spectrum assignment on long term licensing for specified geographical regions resulting in highly inefficient spectrum utilization. Newer wireless applications and their growing popularity are manifesting in greater demand for spectrum. Software defined radio technology employed in dynamic spectrum access mode enables cognitive radio networks to opportunistically communicate on unutilized portion of spectrum at any instant, thus facilitating wider wireless broadband access to unlicensed networks particularly in rural areas in television bands. However, this provision results in a number of different networks contending for the same vacant slots of frequency bands raising probability of uncontrolled interference within the same as well as to other networks. The issue of coexistence among various licensed primary users and unlicensed cognitive radio network users is surveyed and analyzed in this paper.