基于无线网络的流媒体传输拥塞控制的研究

发布时间：2018-04-28 04:50

本文选题：无线网络 + 流媒体　；参考：《重庆大学》2014年硕士论文

【摘要】：流媒体技术的广泛应用和移动互联网的高速发展，使得人们对移动流媒体服务的需求越来越大。大量的流媒体数据在网络中传播，现有的网络资源不足以满足如此大量数据的并行传输，从而产生了网络拥塞。对网络拥塞控制的研究已经持续了十几年，但这类研究并没有针对流媒体数据传输的特点进行优化，特别是在流媒体传输的拥塞预防和流媒体服务质量的保障上，与实际需求有一定的差距。无线网络环境下的拥塞控制研究更是其中的难点和热点之一，也是推动移动流媒体服务发展的重点。本文主要研究无线网络环境下流媒体传输拥塞控制的特点、问题以及解决方法，在对TFRC（TCP Friendly Rate Control Protocol）协议研究的基础上，设计了一种TCP友好的无线流媒体传输拥塞控制系统。本文主要完成的研究工作如下：（1）分析了无线网络的特点以及无线网络环境下数据包丢失的原因；阐述了流媒体传输原理、技术和特点；分析了拥塞控制机制以及拥塞产生的原因，并给出了拥塞控制机制的评价标准。（2）详细分析了TFRC中TCP吞吐量计算方法、TFRC数据包内容和TFRC的工作流程，针对TFRC应用于流媒体传输时存在的问题，对TFRC在拥塞预警、传输平稳性和最小发送速率等方面的不足进行了相应的改进。（3）针对无线网络环境对于TFRC性能的影响，提出了利用ECN（ExplicitCongestion Notification）的特性来进行丢包区分的方法，该方法可以正确区分拥塞丢包和无线误码丢包，根据该方法研究了一种基于ECN的拥塞控制机制及其在Linux系统的实现，并在此基础上设计了TCP友好的无线流媒体拥塞控制系统。（4）对设计的无线流媒体拥塞控制系统进行了测试，依据拥塞控制机制的评价标准，，进行了网络效率、TCP友好性、流媒体播放平稳性和流媒体播放效果等测试并对测试结果进行了分析，测试结果表明本文研究设计的无线流媒体拥塞控制系统达到了预期的设计效果，对同类系统在流媒体传输效果和应用于无线网络环境中的性能等方面有显著提高。综上所述，本文对无线网络环境下的流媒体传输拥塞控制进行了深入研究，并针对现有拥塞控制方法的不足进行了相应改进并设计了无线流媒体拥塞控制系统，最后通过实验验证了新方法的有效性，表明本文设计的无线流媒体拥塞控制系统能够在TCP友好的前提下，保证无线网络环境下流媒体服务的质量。
[Abstract]:With the wide application of streaming media technology and the rapid development of mobile Internet, people need more and more mobile streaming media services. A large number of streaming media data spread in the network, the existing network resources are not enough to meet the parallel transmission of such a large number of data, resulting in network congestion. The research on network congestion control has lasted for more than ten years, but this kind of research has not optimized the characteristics of streaming media data transmission, especially in the congestion prevention of streaming media transmission and the guarantee of streaming media quality of service. There is a certain gap with the actual demand. The research of congestion control in wireless network environment is one of the difficulties and hot spots, and it is also the key to promote the development of mobile streaming media services. This paper mainly studies the characteristics, problems and solutions of congestion control of streaming media transmission in wireless network environment. Based on the research of TFRC(TCP Friendly Rate Control Protocol) protocol, a TCP friendly congestion control system for wireless streaming media transmission is designed. The main work of this paper is as follows: 1) analyzing the characteristics of wireless network and the reasons of packet loss in wireless network environment, expounding the principle, technology and characteristics of streaming media transmission, analyzing the congestion control mechanism and the causes of congestion. The evaluation criteria of congestion control mechanism are also given. In this paper, the method of TCP throughput calculation in TFRC is analyzed in detail, including the content of TCP packet and the workflow of TFRC. Aiming at the problems existing in the application of TFRC in streaming media transmission, the congestion warning of TFRC is given. Some improvements have been made in terms of transmission smoothness and minimum transmission rate. 3) aiming at the influence of wireless network environment on TFRC performance, this paper proposes a method of packet loss discrimination by using the characteristics of ECN(ExplicitCongestion Notification, which can correctly distinguish congestion packet loss from wireless error packet loss. According to this method, a congestion control mechanism based on ECN and its implementation in Linux system are studied, and a TCP friendly congestion control system for wireless streaming media is designed. (4) the designed wireless streaming media congestion control system is tested. According to the evaluation standard of congestion control mechanism, the network efficiency and TCP friendliness are carried out. The test results show that the wireless streaming media congestion control system designed in this paper has achieved the desired design effect. The performance of similar systems in streaming media transmission and wireless network environment has been improved significantly. To sum up, this paper deeply studies the congestion control of streaming media transmission in wireless network environment, and improves the existing congestion control methods and designs the wireless streaming media congestion control system. Finally, the effectiveness of the new method is verified by experiments, which shows that the proposed wireless streaming media congestion control system can guarantee the quality of streaming media service in wireless network environment on the premise of TCP friendly.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.8

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