Allocation of Opportunistic Spectrum in Cognitive Radio Ad Hoc Networks

Cognitive radios (CRs) address the problems of spectrum scarcity and under-utilization of the spectrum. However, realizing a CR network is neither easy nor straight-forward. The link layer in CR ad hoc networks is responsible for choosing suitable channels, out of the available channels, for setting up communication between nodes. However, the selection of channels amongst the CR nodes in the network is proven to be NP-complete. The need of maximizing the spectrum efficiency in a fair way can be modeled as a graph coloring problem. An edge coloring heuristic and a clique determination heuristic algorithms are proposed in this article. We compare the results of these heuristics with the algorithm proposed in. We also compare the spectrum utilization in all these algorithms.