The Research Of Dynamic Spectrum Sharing Algorithm Based On Cognitive Networks

New technologies and services make the wireless communication fast developed. At the same time the requirement of spectrum also increases fast. So the spectrum which is non-renewable becomes scarce. The traditional spectrum allocation mechanism is called static allocation that allocates fixed spectrum to the fixed services, so the utilization of spectrum is low. How to increase the utilization of spectrum to satisfy the requirement of different services has been a hot point in communication research area. The cognitive radio——a very intelligent spectrum allocation technology can sense the communication environment and change the parameter of system (transmitter power, carrier frequency, modulation) automatically by some leaning algorithms. So the TDMA, CDMA and SDMA are available in order to reduce the constraints of the spectrum and bandwidth.In this paper, the spectrum sharing technology has been studied and the price game algorithm has been proposed. At the same time, the supervising-cooperation mechanism which can keep the network safe is proposed based on stackelberg approach. The main contents of the paper are as follows:In Chapter 1, the background of the study in cognitive radio and the structure of this dissertation are introducedIn Chapter 2, the definition and functions of cognitive radio are introduced briefly and the actualities about the research on CR are summarized. Also the key technologies of cognitive radio are explained. Finally, the target of this paper is pointed.In Chapter 3, algorithms about spectrum sharing are introduced in details, including the Graph Theory algorithm and Game Theory algorithm. Then, the security requirement, security risks and the security problems of the existing cognitive networks are introduced.In Chapter 4, the supervising-cooperation mechanism which can keep the network safe is proposed based on stackelberg approach. And the price game process and the leaning algorithm are proposed. We can find that system price is stable when the parameter is in the given range.In Chapter5, simulations about the analysis in chapter 4 are presented. From the simulation graphs we can find that the price of the system can reach stable value when the rate adjustment parameter is in the given range. And the supervising-cooperation mechanism is proved to keep the network safe.In Chapter6, we summarize the dissertation and point out the directions for further study.