This thesis addresses the issue of QoS in WiMAX networks and esspecially the dimensioning of management bandwidth WiMAX network mecanisms i.e: Call admission controll, scheduling mecanism and ressource allocation in physical layer. The challenge of these mechanisms are to take into account concepts introduced by the fixed and mobile WiMAX network as well as adaptive modulation, the subchannelization mecanism, mobility and OFDMA and TDMA multiplexing techniques. This by considering application requirements supported by WiMAX. To do this, our approach was to identify relevant QoS management mechanisms presented in literature, and to adapt them to new concepts of WiMAX technology and propose alternative QoS mechanisms. We proposed an end to end QoS module by taking into account applications constraints and the caracteriscs of physical and MAC layers of the WiMAX standard. An important contribution of the thesis lies in the proposed mathematical model to evaluate the performance of our system by considering QoS mechanisms and to determine through the use of heuristics the best possible dimensionning parameters. The first contribution of this thesis proposes a mathematical model with the aim to give guidelines for the dimensioning of WiMAX bandwidth provisioning service to residential customers in fixed WiMAX network, we considered in this work a combined Guaranteed minimim and Upper Limits CAC strategy. The second contribution is to determine, using an analytical model and a heuristic approach, the nearly-optimal sizes of the partition sizes dedicated to each type of connection in mobile WiMAX by considering the Complete partionning CAC. Finally, we propose a wireless resource allocation (mapping) mecanism of a Mobile WiMAX cell based on OFDMA access technique.