QoS Provisioning in Wi-Fi Networks: Capacity Modeling and Resource Control

dc.contributor.advisorDr. Arne Nilsson, Committee Memberen_US
dc.contributor.advisorDr. Wenye Wang, Committee Memberen_US
dc.contributor.advisorDr. Michael Devetsikiotis, Committee Chairen_US
dc.contributor.advisorDr. Steve Roberts , Committee Memberen_US
dc.contributor.authorHui, Jieen_US
dc.degree.disciplineComputer Engineeringen_US
dc.description.abstractThe ubiquitous Wireless Fidelity (Wi-Fi) networks, and their increasing quality of service (QoS) requirements for emerging applications, motivate extensive studies of QoS provisioning in such networks. Two tasks, namely, capacity modeling and resource control, are crucial in solving the problem: A performance model is first needed to predict the network QoS metrics from the network settings. We propose a new unified analytical model to study the saturation throughput and delay performance of 802.11e Enhanced Distributed Coordination Function (EDCA), which is easier to apply than the most current ones. In order to find usable mathematical models for most cases where analytical models are not feasible, we first advocate the application of metamodeling techniques to Wi-Fi performance studies and formulate a general metamodeling framework for such purpose. The results in three case studies support the validity of our methodology: our saturation capacity metamodel for 802.11 Distributed Coordination Function (DCF) displays an interesting log-linear relationship between capacity and number of users; our voice over Wi-Fi admission capacity metamodel gives a much tighter bound than bounds existing in the literature; and, finally, our throughput metamodel for a simple ad-hoc network, for the first time, characterizes the cross-layer effects between MAC and network layer. Our work, therefore, points out a new direction for future performance studies of Wi-Fi networks. Then, based on the performance models we derive, control schemes of input parameters can be designed to achieve certain level of QoS outputs in some cases. For example, we are able to design a Weighted Round Robin (WRR) scheduler at the MAC layer to control the share of the radio resources, by applying our analytical model to a special case of EDCA configuration. Furthermore, based on our fitted metamodel for the capacity of voice over Wi-Fi, a more practical admission control scheme is composed.en_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectcall admission controlen_US
dc.subjectcross layeren_US
dc.titleQoS Provisioning in Wi-Fi Networks: Capacity Modeling and Resource Controlen_US


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