Research On Hopf Bifurcation Control And Stability Of Internet Congestion Control Model

With the rapid development of the Internet in the world, the Internet has in-depth all walks of life, has also been widely used and developed. At the same time, there have been many technical problems, which restricts the development of the Internet, especially the network congestion control algorithms. So to solve the problems of network congestion is an effective way to improve the network quality of service.This paper studies the Hopf bifurcation problem of the network congestion control system and adopt a new control method to delay or eliminate bifurcation, which is to design a new effective congestion control algorithm provides a theoretical guidance.The research contents and innovation points of this dissertation can be summarized as follows:(1).The control of Hopf bifurcation in a Dual model of Internet congestion control system is studied. In order to solve the insufficient of the standard delayed feedback control method, this paper proposes a dynamic delayed feedback control method based on the washout filter. It is based on the original feedback controller, combined with a dynamic compensation structure, which is a good way to control Hopf bifurcation of the system.(2).The Hopf bifurcation problem of a fluid-flow model for the congestion control in the wireless networks is studied. The standard delayed and dynamic delayed feedback control methods need some previous information of the system, but to obtain these information is often quite difficult in the actual project. Because the dynamic delayed feedback control method increases dimension of the phase space, the difficulty of theoretical analysis increases. To overcome these shortcomings, a state feedback control method is proposed. By choosing the communication delay as a bifurcation parameter, it is proved that with the controller, one can change the critical value of bifurcation and enlarge the stable region, the Hopf bifurcation of the system has been delayed.Moreover, by choosing the appropriate parameters. We can also easily change the stability and direction of bifurcating periodic solutions. Theoretical analysis and numerical results are verified that this method can effectively control Hopf bifurcation of the system.(3).For different bifurcation control methods, the performance of Hopf bifurcation control is different. Therefore, this paper will explore the validity and differences of three bifurcation control methods, which are the standard delayed feedback control method, hybrid control method and state feedback control method. Numerical results are verified that the state feedback control method can most effectively control Hopf bifurcation of the system. Studies of these control methods will improve the performance of congestion control in the wireless network, especially its application in wireless network of large delay and high link errors, it is possible to improve the stability and network transmission efficiency.