Cross-layer Optimization Strategies for Video Transmission over Ieee 802.11e Networks

This paper presents two cross-layer optimization strategies based on the IEEE 802.11e standard that enable a robust video transmission using adaptively Forward Error Correction (FEC) channel codes at transport layer and a Multiple Description Coding (MDC) architecture. The first approach classifies the characteristics of the sequence to be coded and selects the most appropriate coding mode according to the channel conditions obtained through a cross-layer signalling protocol. The second relies on a parametric model of the distortion which is estimated during the coding operations. The performance of the MDC scheme is then improved by a packet classification strategy based on their significance in the multiple description decoding scheme. Experimental results show that both cross-layer optimization algorithms perform well with a small computational effort but different playout delays. As for the MDC packet classification, the PSNR value can be increased up to 2 dB depending on the characteristics of the coded video sequence.