中文摘要：

基于TCP反馈的主动队列管理算法会无差别地丢弃UDP分组，导致视频质量下降．根据TCP／UDP发送特性和混合流排队机制，推导拥塞窗口、丢弃概率及混合流队列长度的微分方程，通过线性化获得Ad Hoc网络混合流AQM（active queue management）控制模型，提出了一种减少UDP丢弃率的PI-V主动队列管理算法．当视频画质下降时，算法依据视频帧权重与分组长度，动态地调整UDP视频流的丢弃概率．NS（network simulator）仿真表明，PI-V算法优于PI与去尾算法，提高了视频传输质量0．82 dB～2．22 dB的峰值信噪比（PSNR）．

英文摘要：

An active queue management （AQM）algorithm,based on TCP feedback,will drop UDP packets indis-tinguishably,leading to a dropin UDP video quality.Congestion window-size,drop probability,and the dif-ferential equations of the hybrid flow queue length are deduced based on TCP/UDP transmission characteris-ticsand hybrid flow queuing mechanisms.An Ad Hoc network hybrid flow AQM control model is obtained through the linearization of these equations.A PI-V AQMalgorithm is proposed,which reduces the drop-rate of UDPs.This algorithm dynamically modifies the drop probability for UDP video stream,adjusting to video frame weight and packet length as the transmission quality changes.NS （network simulator）simulations dem-onstrate that this PI-V algorithm′s performance is better than that of the PI and drop-tail algorithms.The to-be-discussed PI-V AQMalgorithm improves video transmission quality by 0.82 dB-2.22 dB,as determined from the peak signal-to-noise ratio.