Dynamic Cross-Layer Adaptation of Scalable Video in Wireless Networking

The recent trend in Internet traffic indicates the proliferation of usage of multimedia services where a substantial part is related to some sort of video transmission. Moreover, an increasing number of Internet users employ wireless access technologies. High-quality video streaming over wireless access in unison with great mobility brings challenges to sustain the mobile user perceived video quality high. Capacities of wireless links vary due to, for instance, coverage area limitations, multipath propagation, and fading. However, novel video codecs utilize a layered encoding/decoding mechanism, which conveniently allows adapting the video quality, and thus the bitrate, by adjusting the number of layers transmitted. In this study, we exploit an extensive cross-layer signaling framework for a dynamic scalable video adaptation in varying network capacity. We focus on comparing a fast and fair MAC-layer packet scheduling with a relatively slow and long-term adaptivity taken place already at the application layer using a real H.264/SVC video. Our results attest the advantages of adaptation through the use of feedback signaling, which enables continuing the use of the current network access despite its capacity variation.