Biologically-Inspired Distributed Spectrum Access for Cognitive Radio Network

Cognitive radio is an emerging technique to improve the utilization of the scarce radio frequency spectrum, which is characterized by the dynamic spectrum access of the secondary users coexisting with the primary users. In cognitive radio network, secondary users strive for temporally unused spectrum access opportunities offered by primary services; as a result, the opportunistic nature of the spectrum utilization among secondary users leads to great threats to primary users. Considering the fact that the cognitive ability of secondary users in cognitive radio network are similar to the intelligent behaviors of ant colonies in biological environment. Therefore, in this paper, the dynamic spectrum access problem is modeled as an adaptive task assignment in ant colonies. Furthermore, we propose to use the ACO algorithm to assign a set of secondary users to a given number of available spectrum bands owned by a special primary service subject to minimal cost constraint. So the basic idea of the ACO algorithm is to let each secondary user distributively select a spectrum band with a good enough quality and without interfering with the primary users, meanwhile minimize spectrum cost of the primary service. Performance evaluation has also been conducted and the results recorded after 100 runs have shown the optimal spectrum assignment.