A Distributed Multichannel MAC Protocol for Cognitive Radio Networks with Primary User Recognition

A Cognitive Radio (CR) network should be able to sense its environment and adapt communication to utilize unused licensed spectrum without interfering with the licensed users. In this paper we will look at CR-enabled networks with distributed control. Since CR nodes will need to hop from channel to channel to make the most use of the spectrum opportunities, we believe distributed multichannel MAC protocols to be key enablers for these networks. Besides the spectrum scarcity, energy is rapidly becoming one of the major bottlenecks of wireless operations and has to be considered as a key design criterion. We present here an energy-efficient distributed multichannel MAC protocol for CR networks. Simulation results show that this protocol significantly improves performance by borrowing licensed spectrum and protects primary users from interference, even in hidden terminal situations. Sensing costs are evaluated and shown to contribute only 5% to the total energy cost.