高速移动下基于链路反馈的网络拥塞算法研究

发布时间：2018-04-04 21:38

本文选题：高速移动　切入点：网络拥塞　出处：《北京交通大学》2017年硕士论文

【摘要】：随着高速铁路的快速发展,高速移动通信网络成为高速铁路信息化建设的重要方向之一。高铁移动通信网主要分为铁路专网和用户开放式网络。本文根据特定的用户开放式高铁移动通信网为研究背景,结合当前高速网络拥塞控制算法的研究现状和发展趋势,对网络拥塞控制算法进行优化与改进,并提出了提高网络服务质量的高速网络拥塞控制算法。算法性能分析和仿真结果表明,该算法在高速铁路特定场景下可以提高网络性能与服务质量。本文的主要工作具体如下:(1)提出了一种基于非线性丢包率的自适应拥塞控制算法,称为GTRED算法。该算法主要解决了 TRED算法队列长度震荡过大的问题。GTRED算法采用分段三次函数计算丢包概率,并将平均队列的长度扩大到2倍的最大阈值,在扩大算法作用范围的基础上,实现了动态网络环境中队列长度的稳定。实验仿真结果表明,该算法可有效权衡高低流量负载之间延迟和吞吐量的关系,解决队列长度震荡过大的问题,具有更好的鲁棒性和稳定性,而且能够有效的提升网络性能。(2)提出了一种基于链路反馈的网络拥塞控制算法,称为Pre-HSTCP算法。通过对HSTCP算法、Fast TCP算法、STCP算法等高速网络拥塞控制算法的深入研究,在对高速铁路特定研究背景的特殊性进行详细分析的基础上,得出其固定路线上的丢包率具有一定规律性的结论,将固定路线上的丢包率规律作为判别网络拥塞情况的条件之一,对高速网络拥塞控制算法进行改进与优化,进一步提高了高速铁路环境下用户开放式移动通信网络的性能。(3)通过NS2实验平台对Pre-HSTCP算法进行仿真实验,其仿真结果充分证明了该算法的性能优势。Pre-HSTCP算法通过提前调整窗口大小的形式,可以有效降低丢包率,充分利用链路带宽,使高速铁路通信网络获得平稳的数据流和较高的网络吞吐量。
[Abstract]:With the rapid development of high-speed railway, high-speed mobile communication network has become one of the important directions of high-speed railway information construction.High-speed railway mobile communication network is mainly divided into railway private network and user open network.In this paper, according to the research background of specific user open high-speed railway mobile communication network, combined with the current research status and development trend of high-speed network congestion control algorithm, the network congestion control algorithm is optimized and improved.A congestion control algorithm for high-speed networks is proposed to improve the quality of service.The performance analysis and simulation results show that the proposed algorithm can improve the network performance and QoS under the specific scenario of high-speed railway.The main work of this paper is as follows: (1) an adaptive congestion control algorithm based on nonlinear packet loss rate, called GTRED algorithm, is proposed.The algorithm mainly solves the problem of excessive queue length oscillation in TRED algorithm. GTRED uses piecewise cubic function to calculate packet loss probability, and extends the average queue length to the maximum threshold of 2 times.The queue length in dynamic network environment is stable.The experimental results show that the proposed algorithm can effectively balance the relationship between the delay and throughput between high and low traffic loads, and solve the problem of excessive queue length fluctuations, and has better robustness and stability.This paper proposes a network congestion control algorithm based on link feedback, which is called Pre-HSTCP algorithm.Through the deep research on the congestion control algorithms of high-speed network, such as HSTCP algorithm, Fast TCP algorithm, and so on, the particularity of the specific research background of high-speed railway is analyzed in detail.It is concluded that the packet loss rate on the fixed route has certain regularity. Taking the law of packet loss rate on the fixed route as one of the conditions for judging the network congestion, the congestion control algorithm of the high-speed network is improved and optimized.The performance of user open mobile communication network in high-speed railway environment is further improved. The simulation experiment of Pre-HSTCP algorithm is carried out through NS2 experimental platform.The simulation results show that the pre-HSTCP algorithm can effectively reduce the packet loss rate and make full use of the link bandwidth by adjusting the window size in advance.Make the high-speed railway communication network to obtain stable data flow and high network throughput.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U285.21;TN929.5

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