基于哈密顿理论的TCP网络拥塞控制研究

发布时间：2018-06-12 18:36

本文选题：TCP网络 + 拥塞控制　；参考：《东北大学》2014年硕士论文

【摘要】：随着科学技术的不断发展,新型网络应用的出现以及网络用户的不断增加导致网络拥塞成为亟待解决的问题。基于路由器的主动队列管理机制,与TCP协议的拥塞控制相结合,是解决目前TCP网络拥塞控制问题的一个主要途径。考虑到TCP网络的强非线性,本文利用哈密顿理论来设计控制器。哈密顿理论是一种基于能量的控制方法,不仅结构形式简单,而且在控制器设计和稳定性分析方面也具有巨大优势。因此,针对TCP网络系统,本文首次尝试采用哈密顿理论控制方法设计控制器,成功解决了网络拥塞的问题。本文的主要研究内容有：首先介绍TCP网络拥塞控制研究的背景和意义,阐述了网络拥塞发生的原因,总结了国内外拥塞控制算法的研究现状,针对网络拥塞存在的问题,分析了网络拥塞控制算法设计存在的难点,并且说明了哈密顿理论的研究现状。其次阐述了哈密顿控制方法的基础理论,结构特点以及建立哈密顿模型所需要的构造方法。同时考虑到具体的网络是一个参数时变、强非线性的动态系统,为了能够更好的适应网络的变化,利用哈密顿系统是一种基于能量函数的控制方法,能够很好地处理非线性的特点,采用预置反馈方法来建立网络拥塞控制系统模型。然后基于哈密顿理论设计了TCP的网络拥塞控制器。利用前面所建立的基于哈密顿理论的TCP网络数学模型,设计了哈密顿控制器,并且对其稳定性进行了理论分析,最后仿真分析,和传统的PI控制器的仿真图进行了比较,结果表明哈密顿控制器的快速性和稳定性明显优于PI控制器,能够有效避免网络拥塞。再者基于已经建立哈密顿理论的TCP网络拥塞模型,针对系统中的UDP流等干扰,采用极小极大控制法处理干扰项,构造了与性能指标相关的检验函数,充分估计干扰对系统的影响,有效降低了传统干扰处理方法的保守性。同时针对TCP网络系统中的参数不确定性,加入了自适应控制,设计了自适应律。仿真分析表明,所提控制策略有效改善了系统的暂态稳定性和鲁棒性。最后进行了总结与展望。对本课题研究内容做了总结,并分析了哈密顿理论在拥塞控制中的研究前景。
[Abstract]:With the development of science and technology, the emergence of new network applications and the increasing number of network users, network congestion has become an urgent problem to be solved. The active queue management mechanism based on router, combined with the congestion control of TCP protocol, is a main way to solve the congestion control problem of TCP network. Considering the strong nonlinearity of TCP network, the controller is designed by using Hamiltonian theory. Hamiltonian theory is an energy-based control method, which is simple in structure and has great advantages in controller design and stability analysis. Therefore, for the TCP network system, this paper first attempts to use the Hamilton theory control method to design the controller, and successfully solves the problem of network congestion. The main contents of this paper are as follows: firstly, the background and significance of the research on TCP congestion control are introduced, the causes of network congestion are expounded, and the research status of congestion control algorithms at home and abroad is summarized, aiming at the problems existing in network congestion. The difficulties in the design of network congestion control algorithm are analyzed, and the research status of Hamiltonian theory is explained. Secondly, the basic theory of Hamiltonian control method, the structural characteristics and the construction method needed to establish the Hamiltonian model are expounded. Considering that the concrete network is a dynamic system with time-varying parameters and strong nonlinearity, in order to adapt to the change of the network, the Hamiltonian system is a control method based on energy function. The model of network congestion control system is established by preset feedback method. Then a TCP congestion controller based on Hamiltonian theory is designed. Based on the established mathematical model of TCP network based on Hamiltonian theory, the Hamiltonian controller is designed, and its stability is analyzed theoretically. Finally, the simulation results are compared with the traditional Pi controller. The results show that the Hamiltonian controller is superior to Pi controller in speed and stability, and can effectively avoid network congestion. Thirdly, based on the congestion model of TCP network based on Hamiltonian theory, aiming at the interference such as UDP flow in the system, the minimal maximum control method is used to deal with the interference item, and the test function related to the performance index is constructed. The influence of interference on the system is fully estimated, which effectively reduces the conservatism of traditional interference processing methods. At the same time, adaptive control is added to the parameter uncertainty of TCP network system, and an adaptive law is designed. Simulation results show that the proposed control strategy can effectively improve the transient stability and robustness of the system. Finally, the conclusion and prospect are given. The research content of this paper is summarized, and the research prospect of Hamiltonian theory in congestion control is analyzed.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP393.06

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