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Contribution à la qualité de service dans les réseaux d'accès sans-fil

Abstract : Abstract : This thesis is a contribution to specifying, modelling and evaluating Quality of Service mechanisms destined to Wireless Local and Metropolitan networks. The first part of this work is the modelling, using Markov chains, of the IEEE 802.11e EDCA access scheme. The model we introduce adds, with regards to state of the art models, mechanisms present in the standard which were not accounted for (explicit consideration of the virtual collision phenomena) and corrects misconceptions with regards to the standard (considering the AIFS periods within the Backoff procedure). The model was rendered synthetic in order to make easier it to use (for this purpose we used the Beizer rules of reduction). The model was then used within a hybrid admission control algorithm, using in its decision process both the model and network state measures. The algorithm was validated and compared to other admission control algorithms using ns-2 simulations. In parallel, we proposed a modification of EDCA's behaviour towards virtual collisions making it fairer. This modification was evaluated using the Markov chain model. A second part of this work was the development, for WiMAX, of bandwidth management framework offering QoS guarantees. This framework is made out of three interacting parts : 1- a bandwidth management for WiMAX that can be modelled as a Latency-Rate server ; 2- an aggregated bandwidth request-response mechanism making the management simpler and more flexible ; 3- an admission control algorithm associated to the architecture guaranteeing its correct functioning. The framework was prospectively developed for heterogeneous wireless networks (WiMAX WMAN interconnecting WiFi WLANs). Our work's perspectives are on this track : defining a complete QoS solution for heterogeneous wireless networks.
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Submitted on : Wednesday, November 18, 2009 - 7:56:52 AM
Last modification on : Friday, October 23, 2020 - 4:36:28 PM
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  • HAL Id : tel-00433043, version 1


Mohamad El Masri. Contribution à la qualité de service dans les réseaux d'accès sans-fil. Informatique [cs]. INSA de Toulouse, 2009. Français. ⟨tel-00433043⟩



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