High-Performance H.264/SVC Video Communications in 802.11e Ad Hoc Networks

This work focuses on improving the performance of video communications based on the recently developed H.264 Scalable Video Coding (SVC) standard over 802.11e wireless networks. The H.264/SVC standard is particularly suitable for wireless communications because of its compression efficiency and the ability to adapt to different network scenarios. The adoption of the H.264/SVC codec in 802.11 networks poses however some issues. In particular, since pictures are encoded into several small video units, the overhead imposed by the 802.11 contention-based channel access mechanism might be large. Thus, the strategy employed for the packetization of the video data plays a key role in determining the performance of the network. This work proposes two network adaptation strategies for H.264/SVC video to efficiently use the QoS-enabled 802.11e extension of the 802.11 standard by designing a scheme for joint optimization of video data aggregation and unequal error protection. Simulations of video transmissions in a realistic home networking scenario characterized by direct communications between devices in ad hoc mode show that the proposed strategies reduce the packet loss rate and significantly improve the quality of the communication with PSNR gains up to about 2 dB. Moreover, the performance of the proposed low-complexity strategy is close to that of the optimal, high-complexity, strategy.