Understanding the Performance and Resilience of Large-Scale Multi-Hop Wireless Networks

Abstract

Wireless networks are becoming an important supplementary technology to the traditional wired networks. They offer convenient and flexible network access for the users to communicate with each other. However, wireless networks confront many technical challenges that limit their full utilization. Especially in large-scale multi-hop networks, the communication quality received by each user depends highly on the cooperation of other users in the network, which is constrained by many factors such as the heterogeneity of user communication devices, the limited availability of radio bandwidth, the difficulty in user coordinations, the mobility of users, and the failure of user devices.

We intend to understand the performance and resilience of large-scale multi-hop wireless networks in this dissertation, which will help us utilize the wireless networks effectively, efficiently and reliably. We identify four fundamental performance and resilience aspects to investigate, namely, the information propagation speed, the communication capacity, the topological stability, and the failure resilience. The study on the first two perspectives attempts to minimize the delay and maximize the capacity of large wireless networks, while the study on the last two perspectives evaluates and mitigates the impact of user mobility and failure on the network structure.

Specifically, we make the following contributions toward improving the utilization of large-scale wireless networks. First, we have determined the maximum information propagation speed in wireless networks and designed a new routing algorithm to identify the minimum transmission delay path for fastest information delivery. Second, we have demonstrated that the maximum network capacity can be obtained by scheduling user transmissions in localized areas and proposed a practical solution for capacity maximization. Third, we have analyzed the network topological stability with presence of user mobility and developed methods to extend the network topology lifetime. Last, we have characterized the spread of correlated user failures and suggested strategies to prevent failures from wide spreading in large wireless networks. The work in this disseration advances our understanding and enhances our utilization of large-scale multi-hop wireless networks.