Practical evaluation of H.264 video streaming over IEEE 802.11e devices by cross-layer signaling

Recent years have seen a growing demand for high quality multimedia traffic over wireless links. Due to the strong demands imposed to all the involved actors, several optimization techniques have been proposed and studied, mostly through theoretical analysis and simulation. In this article we focus on the practical evaluation of H.264 video streaming performance over IEEE 802.11e wireless devices. Measurement results present the effects of employing several key mechanisms which aim to improve the transmission quality over the wireless medium. A cross-layer signaling solution between the application and the MAC layers is implemented, in order to account for the different QoS characteristics of video and elastic traffic. In addition, network support for efficient multiqueue transmission is enabled in the Linux wireless card driver. Measurements also illustrate the effects of changing several H.264 and IEEE 802.11e parameters in the player and driver software.