Distributed Congestion Control of Scalable Video Streams

Abstract

The paper addresses the problem of distributed congestion control in networks where several video stream- ing sessions share joint bottleneck channels. Based on the rate-distortion characteristics of the video streams as well as the requirements of heterogeneous streaming clients, the proposed algorithm determines the utility of rate in- crements in terms of overall quality benefits. We build on the utility-based congestion control framework initially proposed by Kelly (1), (2) and extend it such that it could efficiently handle heterogeneous delays in the network as well as the specific requirements of video streams. We then describe an original implementation of the proposed distributed congestion control algorithm using the common RTP/UDP/IP protocol stack for the efficient streaming of scalable video streams. Each video session independently adapts its streaming rate based on receiver feedbacks, which permits extension to large scale system without central coordination. Finally, we provide extensive simulation results that demonstrate the performance of the proposed solution. It is shown to successfully distribute the network resources among the different sessions such that the overall video quality is maximized. Experiments further demonstrate that the proposed scheme fairly cohabits with TCP, which is certainly an important advantage in today's network architectures.