Browsing by Author "Dr. Ioannis Viniotis, Committee Member"

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    QoS Provisioning and Pricing in Multiservice Networks: Optimal and Adaptive Control over Measurement-based Scheduling
    (2005-08-14) Xu, Peng; Dr. Michael Devetsikiotis, Committee Chair; Dr. George Michailidis, Committee Member; Dr. Peng Ning, Committee Member; Dr. Wenye Wang, Committee Member; Dr. Ioannis Viniotis, Committee Member
    In order to ensure efficient performance under inherently and highly variable traffic in multiservice networks, we propose a generalized adaptive and optimal control framework to handle the resource allocation. Even though this framework addresses rigid Quality of Service concerns for the deterministic delay-bound classes by reserving part of the link capacity and employing appropriate admission control and traffic shaping schemes, our research actually emphasizes the adaptive and optimal control of the shared resources for the flexible delay-bound classes. Therefore, the resource allocation is delivered by a subsystem of this generalized framework, the measurement-based optimal resource allocation (MBORA) system. By applying a simple threshold policy, we first validate the advantages of the adaptivity of our proposed framework through extensive simulation results. Then we introduce a generalized profit-oriented formulation inside decision module of MBORA system, that supplies the network provider with criteria in terms of profit, by leveraging the utility charge revenue and delay-incurred cost. The optimal resource allocation will be affected by the various types of pricing models together with the different levels of service guarantee constraints. As a case study, we investigate this generalized profit-oriented formulation under generalized service models. Combining further with a linear pricing model subject to average queue delay constraints, we propose a fast algorithm for online dynamic and optimal resource allocation under this specific scenario. Finally, we propose a delay-sensitive nonlinear pricing model for the generalized profit-oriented formulation, that realizes two-tier delay differentiation. By better understanding the fluid queueing model, we propose a generalized solution strategy for linear, nonlinear or mixed pricing models that is free of the dimensionality problem and amenable to online implementation.
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    Radio Resource Management in UMTS-WCDMA Systems.
    (2005-12-28) Subramaniam, Kamala; Dr. Wenye Wang, Committee Member; Dr. George Rouskas, Committee Member; Dr. Ioannis Viniotis, Committee Member; Dr. Arne A. Nilsson, Committee Chair
    Universal Mobile Telecommunications System (UMTS) is a Third Generation (3G) cellular technology representing an evolution of a heterogenous mix of services and increased data speeds from today's second generation mobile networks. UMTS uses Wideband Code Division Multiple Access (WCDMA) as its radio air interface. The main advantage of this is its flexibility in resource management. The implementation of WCDMA is a technical challenge because of its complexity and versatility. Billions of dollars have been spent procuring these air interfaces. To exploit the flexibility of the air interface, development of 'Radio Resource Management (RRM)' schemes are imperative. RRM is comprised of power control, handover control, load control and resource allocation algorithms. These ensure optimum network coverage, maximize the system throughput and , guarantee Quality of Service (QoS) requirements to users having different requirements. This research investigates mainly the resource allocation and power control algorithms with which the load control and handover control are intertwined. The state of the art is studied and their pros and cons are discussed, which lays the foundation for the need for more efficient RRM schemes that are eventually presented in this research. The two main schemes considered here are:1)Adaptive Call Admission Control (ACAC) scheme for resource allocation where the system is mathematically modeled as a multi-rate system with priority. Further, a tier based analytical model pertaining to the hierarchical hexagonal cell structure is analyzed and mobility is given importance. 2) Adaptive Uplink Power Control (AUPC) scheme for power control is analyzed where Monte Carlo simulations are used to fine-tune WCDMA link budget parameters. Finally, Location Update (LU) procedures in cellular networks using Bloom Filters is studied where bandwidth gain is given importance. Various performance metrics are observed and two key metrics are given the most importance: the Call Blocking and Call Dropping probabilities. Simulation results are compared to the existing schemes and further strengthened by comparing them to analytical results which validate the entirety of this research.