Research On Spectrum Sharing Technology In Cognitive Radio Systems

With the development of the human society, a variety of new applications have been rapidly growth, increasing the demand for radio spectrum resource. Cognitive wireless network technology can intelligently sense idle spectral bands of the wireless system around them, and "opportunistic" access idle spectrum segment to communicate, achieving the spectrum sharing and improving the utilization of radio spectrum resources effectively. Spectrum sharing techniques based on game theory is now widely used in ways of spectrum sharing. It can ensures the maximize benefits of each user by sharing strategies to the Nash equilibrium and improve the utilization of spectrum resources effectively, which has become a popular direction of cognitive radio field for research.This paper studies the basic principle and key technology of cognitive radio. And then we introduces the basic principle and application of game theory. On this basis, the paper gives the applicability analysis of the game theory applied to spectrum sharing technology of cognitive radio system, and puts forward the spectrum sharing algorithm based on price and the spectrum sharing algorithm based on transmission rate.In traditional spectrum sharing algorithm, the spectrum prices only reflect the demand of secondary users, while in practice, spectrum price is not only related with the demand of secondary users, but also related with the supply of primary users, at the same time, the primary users of different spectrum band have a great influence on secondary users. Aiming at this problem, this paper puts forward to the spectrum sharing algorithm based on price, by introducing spectrum supply and spectrum parameters to redefine the price function of secondary users, which reflected the primary users'control of the spectrum supply and the primary users'wishes to share spectrum. Compared with the traditional algorithms, the new algorithm is closer to the actual network conditions.Taking into account that the cognitive radio system should be able to provide business services such as data, voice and others, these businesses have different quality of service (QoS) requirements, the quality of service for the transmission rate is in higher demand, especially. Therefore, this paper proposes spectrum sharing algorithm based on the transmission rate, taking the transmission rate as the objective function and then defining its utility function. Which can meet the maximize needs of secondary users'transmission rate and then adjust the actual transmission rate adaptively according to the minimum requirements of transmission rate. Simulation results show that this algorithm can avoid the waste of spectrum resources and improve the spectrum utilization more effectively.