Adaptation dynamique des débits des couches pour la transmission vidéo multipoint

The heterogeneous environment of multicast video streams naturally raises a network performance issue which can be addressed using a layered transmission scheme. A receiver is able to adapt the flow rate to its capacity by choosing an adequate subscription level among the different layers. A traditional static approach doesn't allow a full usage of the network capacity and should be combined with an adaptive transmission rate in each layer. We study the dynamic rate adaptation problem and develop a framework integrating a multirate adaptation algorithm and a transmission protocol for layered multicast video. Our main focus is the development of an adaptation algorithm offering rates matching the capacities of the receivers. We also want to set up a congestion control scheme and offer fairness towards TCP flows, while keeping a scalable framework. We evaluate and analyze the proposed architecture using simulations to point out its main characteristics.