Research On Dynamic Spectrum Sharing Algorithm Based On Game Theory

Cognitive radio technology has the ability to sense the wireless communication environment, utilizing the idle radio resources of authorized users in the frequency domain, time domain, and airspace to achieve the efficient utilization of spectrum resources in the heterogeneous network environments and to ease the tense situation of spectrum resources. Spectrum sharing technology is one of the key technologies of cognitive radio, which mainly solves the problems about how to coordinate the use of idle spectrum between primary users and secondary users or among secondary users after sensing the idle frequency band.Game theory studies the strategic choice or confrontation among the decision-making bodies in the competitive case. Spectrum allocation and power control in the spectrum sharing are also related to the strategic choice. Therefore, game theory can be introduced into cognitive radio system to analyze the spectrum sharing problems. In the paper, the spectrum sharing based on game theory is investigated, and the main contents are as follows:1) The spectrum sharing in the different system models based on cooperative game and non-cooperative game are studied. The existence and uniqueness of the Nash equilibrium or Nash Bargaining solution are proved.2) A non-cooperative spectrum sharing algorithm based on interference coordination is developed. And the new utility function and potential function are constructed with potential game theory. The new utility not only takes into account into the amount of interferences but also the secondary user’s throughput. Thus, the secondary users choose the appropriate channel to mitigate interferences without excessive loss of its transmission rate. The existence and uniqueness of the Nash equilibrium point are also proved. The simulation results show that the proposed algorithm in the paper minimizes interference at the same time improves the total throughout of secondary users. The overall performance of the system is enhanced. 3) A joint design of spectrum sharing and admission control algorithm is proposed.The quality of service demands and the deceiving deeds of secondary users are considered in the proposed sharing strategy.In the access control mechanism, a penalty function has been introduced to force the secondary users to compete the spectrum resources according to their actual requirements. Simulation results show that the joint design of spectrum sharing and admission control scheme proposed in this paper maximizes the total profit of secondary users and possesses a high fairness at the same time. With the help of admission control, it not only guarantees to meet the minimum rate demands from the secondary users, but also prevents secondary users from exaggerating their rate requirements.