A Review of Medium Access Control Protocols in Cognitive Radio Networks

To improve the spectrum efficiency, Cognitive Radio technology is introduced with dynamic spectrum access. To achieve the dynamic spectrum access, the cognitive radio network is emerging with spectrum key functionalities such as spectrum sensing, spectrum management, spectrum sharing and spectrum mobility. Medium Access Control (MAC) protocol has an important role in most of the spectrum key functionalities like scheduling the available spectrum resources to choose the best channel based on QoS requirement, negotiation between the users for avoiding the collision and vacate the channel when the primary user is detected. In this review, the roles of MAC protocol in cognitive radio functionalities are analyzed. This review concentrated on the research publication in MAC protocol of past ten years. MAC protocols in cognitive radio network are classified and tabled based on the characteristics such as spectrum access, cooperation between the primary and secondary users, the structure of the network and common control channel. Finally, the advantages and the research challenges of the MAC protocol are identified and described.