Spectrum Sharing Among Multiple Secondary Users in Cognitive Radio Networks

In a cognitive radio network (CRN), secondary (or unlicensed) users intend to share unoccupied frequency spectra of primary (or licensed) users in order to improve the efficiency of spectrum usage. In this paper, we address the problem of dynamic spectrum sharing in a CRN consisting of multiple SUs that compete non-cooperatively and independently with each other to demand spectrum access to a single PU. This situation is formulated as an oligopoly market. For SUs, a new revenue function is proposed in terms of their spectrum demands. Furthermore, the Cournot game model (the same as [4]) is used to define SUs' spectrum demands such that maximize their payoffs. Nash equilibrium is considered as the solution of this game. We consider two different cases: Static Game and Dynamic Game; the stability condition of the proposed dynamic game is investigated. We also compare our results with those of [4]. Simulation results show that our proposed model provides larger shared spectrum sizes, revenues and payoffs for SUs, higher offered prices for the PU, and larger stability region.