Sigmoid utility function formulation for handoff reducing Access model in cognitive radio

This paper investigates the issue of determining an appropriate utility function to model the Secondary User (SU) preference toward spectrum holes on the basis of their duration. A Sigmoid shaped utility function is proposed and a proper tuning is discussed to improve the representation of SU preference and to involve the radio quality on the access decision process. The performance and the suitability of the proposed utility function is investigated within an access model whose purpose is to reduce handoff process related to PU activity.