中文摘要：

针对IEEE802．11的链路层重传机制和分包策略的不足，研究了基于重传时延最小约束的传输层包长调整策略，提出一种适合于无线局域网（WLAN）流媒体传输的可变包长TCP友好速率控制机制（VPTFRC）．与其他方案不同，该机制进一步考查了无线包错误率对包长调整和速率控制的影响．仿真试验结果验证了采用该方法可获得优于TFRC的有效吞吐量、传输延时及抖动等指标，其中，帧传输时延、时延抖动和丢包率的最大改善程度分可达58％，42％和85％．

英文摘要：

In order to improve the link layer retransmission mechanism and packet fragment strategies for IEEE 802. 11, a VPTFRC （variable packet size TCP-friendly rate control） scheme is proposed which is used for streaming media transmission over WLAN by researching on the policy of packet size adjustment in transport layer, based on minimum retransmit-delay constraint. Unlike other proposals, this mechanism takes the impact of wireless packet error ratio （PER） on the packet size adjustment and performance of rate control into consideration. Simulation results demonstrate our proposed mechanism can simultaneously achieve higher goodput, better fairness, shorter transmission delay and less jitter than that of TFRC. Among them, the maximum improvement ratio of delay, jitter and packet loss rate can reach to 58 %,42 % and 85 % respectively.