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Item Efficient Publish/Subscribe System over Mobile Ad-Hoc Network(North Dakota State University, 2012) Liu, ChaoInformation dissemination is an important issue for mobile ad-hoc communities. This issue is very challenging due to the dynamic and fragile nature of the mobile ad-hoc networks, in which participants have limited computing resources and battery, intermittent network connections, and mobile tasks. To address the aforementioned issue, this thesis proposes an efficient semantics-based publish/subscribe strategy. In our proposed publish/subscribe system, distributed mobile participants are organized into clusters based on their location proximity. A compact semantics-based indexing scheme is provided to guide information flow. Intra- and inter- cluster routings are proposed to assist efficient propagation of event notifications. A comprehensive set of simulation experiments prove the effectiveness of the proposed scheme.Item Resource and Bandwidth Allocation in Hybrid Wireless Mobile Networks(North Dakota State University, 2010) Bengfort, Benjamin JohnIn the lead up to the implementation of 802.16 and 4G wireless networks, there have been many proposals for addition of multi-hop MANET zones or relay stations in order to cut the cost of building a new backbone infrastructure from the ground up. These types of Hybrid Wireless Networks will certainly be a part of wireless network architecture in the future, and as such, simple problems such as resource allocation must be explored to maximize their potential. This study explores the resource allocation problem in three distinct ways. First, this study highlights two existing backbone architectures: max-coverage and max-resource, and how hybridization will affect bandwidth allocation, with special emphasis on OFDM-TMA wireless networks. Secondly, because of the different goals of these types of networks, the addition of relay stations or MANET zones will affect resource availability differently, and I will show how the addition of relay stations impacts the backbone network. Finally, I will discuss specific allocation algorithms and policies such as top-down, bottom-up, and auction-based allocation, and how each kind of allocation will maximize the revenue of both the backbone network as well as the mobile subscribers while maintaining a minimum Quality of Service (or fairness). Each of these approaches has merit in different hybrid wireless systems, and I will summarize the benefits of each in a study of a network system with a combination of the elements discussed in the previous chapters.Item Distance-Aware Relay Placement and Scheduling in Wireless Networks.(North Dakota State University, 2011) Bai, ShiThe WiMAX technology and cognitive radio have been active topics in wireless networks. A WiMAX mesh network is able to provide larger wireless coverage, higher network capacity and Non-Line-Of-Sight (NLOS) communications. Cognitive radios enable dynamic spectrum access over a large frequency range. These characteristics make WiMAX mesh networks and cognitive radio networks able to provide users with low-cost, high-speed and long-range wireless communications, as well as better Quality of Service. However, there are still several challenges and problems to be solved in this area, such as relay station placement problems and scheduling problems. In this thesis, I studied a distance-aware relay placement problem and max-min fair scheduling problem in WiMAX mesh networks. To solve these problems, approximation algorithms and heuristic algorithms are proposed. Theoretical analysis and simulation results are provided to evaluate the solutions. I also studied a scheduling problem adopting the idea of cognitive radio technique in wireless networks over water. Two heuristics are presented to solve this unique problem. I provide the numerical results to justify the performance and efficiency of our proposed scheduling algorithms.