Motivated by ubiquitous communication, both wireless network theory and technology have vigorously developed in the past decades that could support broadband wireless access (BWA), and the current trend continues to replace wired network backbone. Conventional network access is served by network infrastructure, which is deployed at fixed locations and acts as "bridge", i.e., gateway, between wired backbone and mobile clients (MCs) with equipped wired-interface and air-interface. Infrastructures have to be placed at the locations where cables available, including network and power cables, which poses strong constraints on deployment locations, and high cost in cable deployment and maintenance.
Wireless mesh networks (WMNs) are comprised of multi-radio mesh routers (MRs), which interconnect each other using wireless links to form a mesh backbone. This also forms a multi-cell architecture to provide network service for MCs, where Internet gateways (IGWs) are special MRs having wired connection to the Internet. The deployment of MRs is flexible, cost-efficient, self-organizing, etc. Mobile MRs even form a mobile mesh backbone. Due to its advantages, WMN could be one of the promising case of the next generation Internet. However, developing such a network also needs to address many fundamental issues inherited from two-tier network architecture, wireless multi-hop transmission, multi-cell structure, etc.
In this dissertation, we analytically model a two-tier WMN and derive the asymptotic bounds of network capacity and delay, which are essential and tightly related factors in developing a WMN to support delay-sensitive applications such as voice over IP (VoIP), video conference, etc. This dissertation performs the analysis on a WMN backbone formed by self-organizing ad hoc MRs and shows how the network capacity is dominated by the network delay constraints, and the numbers of MCs, MRs and IGWs. We find that the network delay scales to either the number of MRs or the number of IGWs, and dominating factors depends on the type of routing strategy. Some of our results are also applicable to ad hoc networks, which can be equivalent to special case of a self-organizing WMN.
We optimize the backbone capacity by introducing two types of channel assignment schemes in managing spectrum resource and mitigating backbone interference. One is a centralized channel assignment scheme, which is suitable to WMNs deployed by Internet service providers (ISPs), and the other is a distributed channel assignment scheme, which applies to static or mobile self-organizing WMN. In addition, we propose a clustering based fractional frequency reuse for multi-cell coverage of WMNs, which offers resource allocation higher flexibility and better fairness with additional spatial dimension. Our work is to analyze and solve the fundamental problems in developing WMNs for ubiquitous and pervasive access. The results in our dissertation can serve as the guideline in research and design of practical WMNs. We conclude with dissertation with some discussion on future area of research.