Cooperative game theory and auctioning for spectrum allocation in cognitive radios

This paper addresses the problem of spectrum sharing in cognitive radios where secondary users (SUs) cooperatively sense the spectrum for identifying and accessing unoccupied spectrum bands. It is shown that spectrum sensing and sharing scenario can be modeled as a transferable utility (TU) cooperative game and that Vickrey-Clarke-Groves (VCG) auction mechanism can be used to allocate spectrum resources fairly to each user. SUs form coalitions to jointly sense the spectrum. The worth of each SU is calculated according to the work done for the coalition in terms of the information obtained about primary user (PU) activity from sensing the spectrum. The resulting games are balanced and superadditive and each SU gets a pay-off according to her worth in the coalition. Depending upon their spectrum needs, SUs use this pay-off to bid for unoccupied bands of spectrum through an VCG auction. VCG auction mechanism provides SUs with an incentive to bid truthfully according to their demand and is socially optimal. The concepts and results are illustrated using a simple example.