A channel negotiation MAC protocol for distributed cognitive radio network

Abstract

Increasing demand for wireless spectrum bands due to the proliferation of wireless protocols introduc-es novel radio technique, cognitive radio technique. The key idea of the technique is to employ licensed spec-trum bands which remains as idle states at any given location and time. Cognitive radio network has an objective to use white spaces effectively without interfering the primary user activity. A lot of cognitive radio MAC protocols have been proposed to support the functions. Common control channel approach use dedicated control channel. It can suffer from control channel saturation when a large number of nodes access to the channel. Split phase approach divided time into beacon interval which is separated into control phase and data phase. All nodes tune their transceivers to one channel and the other channels are remained as idle states during control phase which cause inefficient spectrum usage. And it requires tight time synchronization that is hard to achieve in a distributed cognitive radio ad hoc network. In frequency hopping approach, all nodes hop together according predefined hopping pattern for exchange of control messages. However, it also requires strict time synchronization which is difficult to attain with a large number of nodes. We propose a novel MAC protocol for distributed cognitive radio network. The contribution made in this paper is twofold: (i) cognitive users have different main channel to exchange control messages for diffuse control channel, (ii) tight time synchronization between nodes aren`t required because each node maintains main channel of neighbors. We compare our protocol with other protocols using common control channel and frequency hopping approach in terms of main channel modification, control overhead and aggregate throughput.