Protocol Design and Optimization for QoS Provisioning in Wireless Mesh Networks
Zhou, Wei (2009) Protocol Design and Optimization for QoS Provisioning in Wireless Mesh Networks. PhD thesis, Iowa State University.
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Wireless Mesh Network (WMN) has been recognized as a promising step towards the goal of ubiquitous broadband wireless Internet access. By exploiting the state-of-the-art radio and multi-hop technologies, mesh nodes in WMN collaboratively form a stationary wireless communication backbone. Data packets between clients and the Internet are routed through a series of mesh nodes via one or multiple paths. Such a mesh structure enables WMN to provide clients high-speed Internet access services with a less expensive and easier-to-deployment wireless infrastructure comparing to the wired counterparts. Due to the unique characteristics of WMN, existing protocols and schemes designed for other well-studied wireless networks, such as Wi-Fi and Mobile Ad-hoc Network, are not suitable for WMN and hence cannot be applied to WMN directly. Therefore, novel protocols specifically designed and optimized for WMN are highly desired to fully exploit the mesh architecture. The goal is to provide high-level Quality-of-Service (QoS) to WMN clients to enable a rich portfolio of applications and scenarios. This dissertation work investigates the following issues related to QoS provisioning in WMN: high throughput routing between WMN clients and the Internet, fairness provisioning among WMN clients and network-level capacity optimization. We propose innovative solutions to address these issues and improve the performance, scalability and reliability of WMN. In addition, we develop CyMesh, a multi-radio multi-channel (MRMC) wireless mesh network testbed to evaluate the capacity and performance of WMN in real wireless environments. Extensive simulation results (using QualNet simulator) and experimental (over the CyMesh testbed) demonstrate the effectiveness of the designed protocols. In particular, we learn that the system capacity of WMN can be improved significantly by exploiting the MRMC network architecture and the antenna directionality of radios equipped on mesh nodes, and our proposed fulfillment based fairness is a reasonable notion for fair service provisioning among WMN clients. Moreover, we report on the encountered problems, key observations and the learned lessons in the design and deployment of CyMesh, and our implementations and feasibility tests have demonstrated enough advantages to motivate further experimenting in MRMC WMNs.
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