802.11e中失真驱动的视频传输跨层优化

针对H.264视频在802.11e无线网络中传输时，由丢包和编码量化引起的接收端失真问题，提出了一种以失真为驱动的跨层优化算法，以减少接收端的失真。通过率失真模型得到量化参数(QP)和量化失真之间的关系后，根据不同视频数据分区的丢包率，估计出接收端的传输失真和总体失真；然后，以这个总体失真为依据，提出一个求最优量化参数的选择算法。实验结果表明，所提方法相比只针对H.264视频不同数据分区赋予不同传输优先级的由上向下跨层架构，或者只考虑根据传输丢包率调整编码器量化参数的由下到上的跨层架构，平均峰值信噪比(PSNR)提高了1~2dB，具有更小的接收端失真。

Distortion-driven cross-layer optimization for video transmission over 802.11e

Distortion of H.264 video over 802.11e is jointly caused by transmission packet loss and encoder quantization, to tackle this issue, this paper proposed a distortion-driven cross-layer video transmission optimization. The relationship between Quantization Parameter (QP) and quantization distortion was obtained firstly by a rate-distortion model. Then according to the loss rate of video data partition, the transmission and total distortions at the receiver side were estimated. Based on the total distortion, a selection algorithm of optimal quantization parameter was presented. The experimental results show that, compared with the method of up-bottom cross-layer optimization with various queue priorities for video data partitions and bottom-up cross-layer optimization with an adaptive quantization parameter selection, the proposed method gets 1~2dB average Peak Signal-to-Noise Ratio (PSNR) improvement, and it has less distortion at the receiver side.