Research About Streaming Media Congestion Control In Wireless Network Environment

With the wide range of application of the streaming media technologies and therapid development of mobile Internet, the demand for mobile streaming media servicehas become more and more acute. With large amount of streaming media data and otherforms of data spreading in the Internet. The existing network resources are insufficientto meet such large amount of data transmitting in parallel, resulting in networkcongestion. Research on network congestion control has been going on for over tenyears. But these studies are not optimized for the characteristics of streaming media datatransmission, especially in the prevention of congestion and the guarantee of quality ofservice for streaming media transmission, and there is a gap between these studies andactual demand. Congestion control in a wireless network environment is difficult andone of the research heat, and is vital in promoting the development of mobile streamingmedia services.This paper studies the characteristics, problems and solutions of streaming mediatransmission congestion control in wireless network environment. Based on the researchon existing streaming media transmission technologies and TFRC (TCP Friendly RateControl Protocol), this paper designed a streaming media transmission congestioncontrol system in wireless network environment. Main works of the thesis are presentedin four parts as follows:(1)Studied the characteristics of wireless networks, and analyzed the causes forpacket loss in wireless network environment. Studied the principles, technologies andcharacteristics of streaming media transmission. Studied the congestion controlmechanism, and analyzed the causes for congestion. And evaluation criteria of thecongestion control mechanism were given.(2)Researched on the TFRC protocol mechanism, analyzed the TCP throughputequation, packet content and workflow of TFRC in details. Discovered the problems ofTFRC when applied to streaming media transmission. And some correspondingimprovements on the congestion warning, smooth transmission and minimumtransmission rate have been achieved.(3)Studied the impact of performance of TFRC in wireless network environment.Analyzed several classic loss differentiation mechanism. Proposed a method which usesECN (Explicit Congestion Notification) to differentiate loss, this method can distinguish between congestion loss and wireless error packet loss correctly. And modified theimplementation of ECN in the Linux system according to the actual needs. Designed acongestion control mechanism based on ECN, and on this basis, designed a streamingmedia congestion control system.(4)Tested the streaming media congestion control system. In accordance with theevaluation criteria of congestion control mechanisms, network efficiency, TCPfriendliness, smoothness of streaming media playing and the effect of streaming mediaplayback are tested, and the results are analyzed. The test results show that thestreaming media congestion control system proposed achieved the desired effect. Theeffect of streaming media transmission and the performance applied in wireless networkenvironment improved significantly compared with similar systems.In summary, this paper has researched on streaming media transmission congestioncontrol in wireless network environment deeply. Introduced correspondingimprovements for the deficiencies of the existing methods. And finally proved theeffectiveness of the new method through the experiments, the proposed new design ofstreaming media congestion control system can ensure the quality of streaming mediaservices in wireless network environment under TCP-friendly premise.