Implementation Issues for a Video Streaming Server in IEEE 802.11e WLANs
Gabriel Lazar, Tudor Mihai Blaga, Virgil Dobrota
Recent years have seen a proliferation of real-time multimedia traffic over a more and more heterogeneous Internet. Video streaming at high, consistent quality over wireless links proves to be a difficult task. Several optimization techniques have been proposed and studied, mostly through theoretical analysis and simulation. This article describes the implementation of a cross-layer H.264 video streaming server and the evaluation of its performance in IEEE 802.11e WLANs. Measurements present the benefits of employing several key cross-layer mechanisms which aim to improve the video transmission quality over wireless links. A cross-layer signaling solution is implemented, which addresses important QoS issues between user-space and the kernel traffic control and device driver components. Network support for efficient multiqueue transmission is enabled in the Linux network driver. In addition, the paper discusses the implementation of an enhanced scheduling scheme for the receive-side, in order to provide prioritization of video streams over elastic traffic, and also for better control of latency and improved throughput for multimedia flows.