Optimisation de la capacité des réseaux radio maillés
Christelle Molle · HAL (Le Centre pour la Communication Scientifique Directe) · 2009
In this thesis, we focus on optimizing the capacity of wireless mesh networks. These broadband access networks are a promising solution in urban areas and for military operations. We define the capacity of a wireless mesh network as the fair throughput offered to each flow. In order to get theoretical bounds on the network performances, we develop optimization models integrating the cross-layer characteristics of radio communications. More precisely, we study the joint routing and scheduling problem. We develop, for the linear relaxation of the problem, a resolution method based on the column generation process. We derive a linear formulation which focus on the transport capacity available on the network cuts. We prove the equivalence of the models, and adapt the resolution method into a cross line and column generation process. Thorough tests, we point out a contention area located around the mesh gateways which constraints the network capacity. These results are applied to a quantitative study of the effects of acknowledgments on the capacity. We then present a stability study of a protocol which routes a traffic injected arbitrarily. We improve existing results by showing the stability even if the total traffic injected is a maximum flow. All this research work has been implemented in the open-source library MASCOPT (Mascotte Optimisation) dedicated to network optimization problems.