Graph colouring technique for efficient channel allocation in cognitive radio networks

Cognitive radio networks play a vital role in solving the problem of underutilization of spectrum by identifying unused licensed radio spectrum. They solve the problem by distributing this unused spectrum among unlicensed users in an intelligent fashion without interfering with existing users. In this paper, using the conflict graph and graph colouring concepts, a Graph Colouring based Dynamic Channel Allocation (GC-DCA) algorithm is proposed that minimizes the network interference when the primary users (PUs) and secondary users (SUs) share the channel simultaneously. The performance of the GC-DCA algorithm is evaluated using the OMNeT++ network simulator under different topologies, in terms of channel utilization, end-to-end delay, packet delivery ratio, and throughput. Numerical results show that the proposed technique yields 40.40% increase in channel utilization when the PU and SU share the channel simultaneously.