移动网络下流媒体传输拥塞控制机制的研究

在移动网络环境下，实现流媒体数据的传输已经得到非常广泛的应用。由于经典的TCP友好速率控制机制，在网络发生拥塞时，将无线误码丢包误认为拥塞丢包，会降低网络传输速率，导致网络利用率过度降低。如何保证移动网络环境下流媒体发送端正确区分拥塞丢包和无线链路丢包，实现网络传输速率的准确调整是个很重要的研究课题。本文分析了TFRC协议以及AIMD等拥塞控制机制在该数据传输问题中的适用性，提出了在TFRC协议基础上的一种改进的M TFRC协议，添加了丢包区分算法，可以准确区分丢包类型。通过NS2分析仿真，验证了M TFRC相比TFRC提高了网络吞吐量，维持较高的网络利用率，从而保证移动网络环境下流媒体服务质量。

Research on congestion control mechanism of streaming media transmission over wireless network

Streaming media transmission `has widely used over wireless network. Because of the problem of conventional TFRC mechanism concerning incorrect packet loss rate, when it is applied to mobile congestion networks, the streaming media sever can not get the accurate information of the network condition and thus leading to excessive degrade the sending rate of data. Therefore, an important research issue arises, how to realize loss differentiation between congestion losses and wireless losses and accurate adjustment of network sending rate. Some major congress control protocols including TFRC, AIMD are briefly introduced. This paper propose a mechanism called M TFRC in the base of TFRC ,which appends loss differentiation algorithm. The simulation result shows that M TFRC improves network throughput and the network utilization and guarantee service quality of wireless network streaming media.