Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Automated radio network design using ant colony optimization(Montana State University - Bozeman, College of Engineering, 2008) Sharkey, Jeffrey Allen; Chairperson, Graduate Committee: John PaxtonRadio networks can provide reliable communication for rural intelligent transportation systems (ITS). Engineers manually design these radio networks by selecting tower locations and equipment while meeting a series of constraints such as coverage, bandwidth, maximum delay, and redundancy, all while minimizing network cost. As network size and constraints grow, the design process can quickly become overwhelming. In this thesis we model the network design problem (NDP) as a generalized Steiner tree-star (GSTS) problem. Any solution to the minimum Steiner tree (MST) problem on a constructed GSTS graph will directly identify the tower locations and equipment needed to build the network at an optimal cost. The direct MST solution can only satisfy coverage constraints. Because the MST problem is known to be NP-hard, our research applies ant colony optimization (ACO) to find near-optimal MST solutions. Using ACO also allows us to meet bandwidth, maximum delay, and redundancy constraints. We verify that our approach finds near-optimal designs by comparing it against a 2-approximation algorithm in several different scenarios.Item Performance evaluation of routing protocols for QOS support in rural mobile ad hoc networks(Montana State University - Bozeman, College of Engineering, 2008) Bohannan, Chad Brian; Chairperson, Graduate Committee: Jian TangWe evaluate several routing protocols, and show that the use of bandwidth and delay estimation can provide throughput and delay guarantees in Mobile Ad Hoc Networks (MANETs). This thesis describes modifications to the Dynamic Source Routing (DSR) protocol to implement the Quality Aware Source Routing (QASR) network routing protocol operating on an 802.11e link layer. QASR network nodes exchange node location and flow reservation data periodically to provide information necessary to model and estimate both the available bandwidth and the end-to-end delay of available routes during route discovery. Bandwidth reservation is used to provide end-to-end Quality of Service, while also utilizing the differentiated Quality of Service provided by the 802.11e link layer. We show that QASR performs significantly better in several performance metrics over the DSR and the Ad-Hoc On-Demand Distance Vector (AODV) protocols, and performs more consistently in all quality metrics when traffic demand exceeds network capacity.Item Topology control and interference aware resource allocation algorithms using directional antenna for QoS (802.16e) performance in multi-hop wireless networks(Montana State University - Bozeman, College of Engineering, 2010) Annavarapu, Vishwanath; Chairperson, Graduate Committee: Jian TangIn recent years, there has been a lot of research work being done on the wireless networking using Directional antennas. But not many approached the issue together with resource allocation and channel assignment in multi-channel multi-radio networks, especially in multi-hop WiMAX (802.16e) networks. This work also explores the implementation of Directional antenna for communication in mobile scenario where the nodes move either in specified trajectory or randomly. The overall goal of this research is to work towards improving the wireless communication and proposing solutions for some existing issues. The methods of topology control algorithms for maximizing the minimum link capacity and then a different approach to balance the network load should be one of the few pieces of work in this regard. Implementation of these proposed methods have improved the network performance in aspects like throughput, delay, network capacity, interference, traffic congestion and network balance. The major issues that determine the performance of wireless networks include traffic congestion, interference, signal quality, Quality of Service (QoS), mobility issues like handover. These issues for a multi-hop WiMAX scenario that would possibly emerge in future were studied and solution were suggested and tested. Large numbers of WiMAX scenarios of different sizes with different type of applications, models, devices, resources and methodologies have been simulated and various aspects like mobility, QoS, interference control, traffic congestion and network balance have been studied. During the course of research, various wireless communication issues have been addressed by providing feasible to optimal solutions; new designs and methodologies for the WiMAX models is being incorporated to induce useful functionalities; communication models, antennas and other devices and technically enhanced. Also, the QoS in WiMAX networks hasn't been studied much; our research work includes simulation and detailed analysis of various service classes in different conditions and scenarios for WiMAX multi-hop networks.Item Resource allocation algorithm using directional antennas in WiMAX(Montana State University - Bozeman, College of Engineering, 2009) Gurdasani, Neeraj; Chairperson, Graduate Committee: Brendan MumeyThis paper discusses different algorithms to create directional antenna patterns in OPNET Modeler. We describe algorithms to create conical and pencil beam antenna patterns. We also present a version of this algorithm that creates antenna patterns whose gain follows a cosine squared curve. We have also implemented tracking in OPNET to utilize these directional antenna patterns. These algorithms can be used to create antenna patterns for any wireless technology in OPNET such as WiFi and WiMAX. This paper also discusses an integer linear programming (ILP) formulation for a resource allocation problem. This is a centralized optimization algorithm where the base station decides which subscriber station will be assigned to which relay station in the network such that the throughput of the entire network is maximized. We present some simulation results showing 10Mbps improved throughput using directional antennas with the assignment strategy. This is a centralized algorithm and can be used in any technology that has a centralized resource allocation scheme such as WiMAX.