ABSTRACT
This chapter presents the main differences between cognitive radio ad hoc networks (CRAHN) and regular cognitive radio networks. It addresses the spectrum sharing problem in CRAHN and gives a brief survey of medium access control (MAC) protocols in CRAHN. The chapter also presents scaling laws and CRAHN models and introduces local control schemes and fairness protocols for spectrum sharing. Spectrum sharing is an important function of spectrum management in CRAHNs. Several distributed schemes or algorithms have been proposed in the literature to solve the spectrum sharing problems. In a CRN, the spectrum utilization can be improved if one chooses the appropriate set of channels that meet the transmission rate requirement. The scaling law analysis for wireless networks can give hints to the theoretical bounds of throughput performance. Spectrum availability varies from node to node and from link to link in CRAHNs. The spectrum availability of a CRAHN can be molded as a map by the concept of cellular automaton (CA).
