Vers des mécanismes de routage robustes et optimisés dans un réseau sans fil métropolitain et collaboratif
Chiraz Houadia · HAL (Le Centre pour la Communication Scientifique Directe) · 2016
Wireless Mesh Networks provide infrastructure to interconnect access stations innetworks of different technologies. They have a mesh topology where all the routersare connected with no central hierarchy. Routing in WMNs must be carried out whileoptimizing network resources and respecting the best user QoS requirements. In thisthesis, we propose a QoS-oriented routing in a metropolitan wireless network usinga cross-layer approach. We first studied the impact of the PHY and MAC layers onrouting to deduce the best combination protocol for a wireless mesh network. We havesubsequently focused our work on studying the behavior of the OLSR routing protocolwith different routing metrics. The results of this study confirmed the limits of exis-ting metrics to reproduce the real link quality and raised a number of optimizationpoints on which we focused. We have, therefore, proposed new metrics that provideinformation about link quality, based on PHY and MAC caracteristics, including thelink availability, the loss rate, the available bandwidth, etc. These low layers parame-ters are acquired using a cross-layer mechanism. These metrics allow to apprehendinter-flow interferences and avoid bottleneck formation by balancing traffic load onthe links. Based on the conflict graph model and calculation of maximal cliques, weproposed a method to estimate the available bandwidth of a path which considers,in addition, intra-flow interferences. Finally, we proposed a routing protocol that sup-ports this metric and we studied by simulation its performances compared to differentexisting routing metrics and protocols. The results revealed the ability of our protocolto support the network scalability as well as its ability to choose routes with highthroughput and limited delay, thus, better delivery of data traffic.