在无线网络高误码率的环境下,经典TFRC机制会将无线误码丢包误认为拥塞丢包,导致吞吐量过度降低.针对无线网络实时流媒体业务的传输控制问题,提出了一种改进型动态自适应TFRC机制(Adaptive-TFRC).它在接收端利用丢包区分参数来真实反映网络的状态(即拥塞或者误码),然后反馈至发送端,同时对经典TFRC机制的吞吐量模型公式进行改进,最终能够根据实时网络条件动态自适应地调节传输速率.仿真结果表明,Adaptive—TFRC机制能够有效地提高网络吞吐量,降低实时业务流的延时抖动,同时能够进一步改善TCP业务的友好性传输,从而保证无线网络实时流媒体的服务质量.
In the high error rate wireless network environment, packet loss caused by wireless error will be misunderstood as congestion packet loss by the classic mechanism of TFRC, leading to lower throughput. To solve the transmission control problem of the wireless network for real-time streaming media service, the paper proposed a mechanism called Adaptive-TFRC which was an improved mechanism of TFRC, which can reflect the true state of the network by using loss differentiation parameter of the receiving end, then the value of parameter would be sent back to the sending end, also we have improved the throughput model formula of the classic mechanism of TFRC in this paper, finally it can realize the dynamic adaptation of transmission rate. The simulation result shows that Adaptive-TFRC can greatly improve the throughput, reduce the delay jitter of real-time traffic, and it posses TCP friendly characteristic very well, thus guaranteeing service quality of the wireless network real-time streaming media.