ABSTRACT
Cognitive radio networks (CRNs) have been proposed in recent years as a revolutionary solution towards more efficient utilization of scarce spectrum resources in an adaptive and intelligent way through opportunistic use of frequencies reserved for licensed users of the bands. This chapter provides a unified view of CRNs through step-by-step introduction of different associated concepts and techniques. It highlights different applications of CRNs and discusses a case study of wireless medical networks. The basic components of CRNs are the mobile stations, base stations/access points, and backbone/core networks. These basic components compose three kinds of network architectures in CRNs: infrastructure, ad hoc, and mesh architectures. Many researchers are currently engaged in developing the communication technologies and protocols required for CRNs. However, challenges still remain because CR-enabled networks have to coexist with primary users (PUs) as well as secondary users (SUs) and need to mitigate interference in such a way that they can provide better end-to-end support to ensure efficient spectrum-aware communication.
