Study On Spectrum Allocation Based On Game Theory In Cognitive Radio System

The fixed division radio spectrum resources caused the spectrum resource utilization rate is not high, and it unable to meet the needs of the rapid growth of wireless communication service. Cognitive radio can realize sharing of spectrum resource, dynamic spectrum allocation, which can effectively improve the spectrum efficiency. Spectrum allocation based on game theory techniques are now widely used method of spectrum allocation. Nash equilibrium ensures system stability and spectrum allocation for each user benefit most effectively improves the spectrum resource utilization rate. This paper summarized the cognitive radio technology, and analysis the spectrum allocation algorithm based on game theory, and then improve the existing algorithm based on the secondary user game model, which users can choose according to different frequency spectrum and realize cooperative spectrum allocation, improve the utilization of spectrum resources effectively.As the price of primary user provided for each secondary user is the same in the traditional spectrum allocation based on secondary user game model. Namely the prices function of each secondary user is the same. Therefore, the utility function of the secondary user cannot reflect the spectrum allocations will of primary users to secondary users, at the same time the primary users cannot change the price to each secondary users according to each secondary users spectrum needs. And actually using spectral bands of different users, transmission quality is different. Aiming at this problem, this article proposes a spectrum allocation algorithm based on spectrum interval factor. By introducing spectrum interval factor and alternative factor, it makes the algorithm reflect the primary’s intention from secondary users’utility function. The primary can make the spectrum price according to different frequency interval, and the secondary users improve the utilization to select spectrum according to different frequency band.In non-cooperative spectrum allocation algorithms in the past, each secondary user pursues their own interests, without concern for other user’s interests and collective interests. To solve this problem, this paper proposes cooperative spectrum allocation algorithm based on interval factor. The product of multiple secondary users’utility function is defined as a new utility function. New algorithm does not care about each secondary user’s interests, only care about the interests of the collective. And it achieves optimal collective interest, efficiency principles of fairness, and the purpose of the cooperation spectrum allocation between secondary users. In addition, the algorithm is introduced priority parameters. Secondary user can allocate spectrum by priority parameters according to the proportion of allocating spectrum. Simulation results show that the improved spectrum allocation algorithm can effectively improve the spectrum efficiency, fair and reasonable allocation of spectrum resources.