Cognitive radio spectrum assignment and handoff decision

Spectrum management task is difficult to achieve in a dynamic and distributed network where cognitive radio users may only make local decision and have to react to the environment changes. In this paper, we describe a novel spectrum management approach for a cognitive radio ad-hoc network. Our proposal is based on multi-agent auctions and provides a decentralized control. First, we implement in a realistic way the auction based protocol for spectrum allocation and handoff decision. We make a comparison between two types of spectrum allocations, which are uni-band and multi-band assignments. Second, we introduce a mechanism that takes into consideration the frequency used by the cognitive radio user during the handoff in order to reduce the number of spectrum handoffs. Then, we integrate a learning module in the cognitive radio users´ behaviors to accelerate their spectrum band allocation. Simulation results prove that our algorithm ensures high spectrum utilization rate and confirms the contributions of our protocol in terms of frequency handoff rate and number of users´ attempts before spectrum access.