Misbehavior Resistant Fair Scheduling in Wireless Backhaul Mesh Networks

IYER, VARAGUR K. Misbehavior Resistant Fair Scheduling in Wireless Backhaul Mesh Networks. (Under the direction of Dr. Peng Ning). Wireless Mesh Networks (WMNs) are increasingly becoming popular as a means to realizing cost-effective and efficient public area networks. WMNs provide improved coverage with relatively cheaper infrastructure and are easy to deploy and expand as compared to Wireless LANs. This is possible due to the use of wireless multihop routing to forward traffic from nodes to a Gateway (GW) that has a wired connection to the Internet. However, there are several issues that need to be addressed to realize the practical deployment of large scale mesh networks serving a vast number of clients. Fairness is one such key issue of concern in WMNs, however, WMNs based on existing 802.11 technology exhibit severe unfairness. Several TDMA based bandwidth scheduling schemes have been proposed as an alternative to ensure fairness in WMNs. Such schemes implicitly trust the nodes in the network and as a result, are vulnerable to threats due to misbehavior by nodes participating in the scheduling. These threats are further amplified in public area mesh networks where nodes have highly varying demand and are vulnerable to capture. While a lot of research has been done on securing routing and topology control protocols against misbehavior, the effects of misbehavior on fair scheduling have not been considered. In this thesis, we address the threats to fair scheduling in wireless backhaul mesh networks from node misbehavior and present a generic verification framework to detect such misbehavior. The verification framework is based on the argument that, while the actions of an individual node might not be trusted, the collective action of all the nodes in the network can be trusted since an attacker is assumed to be incapable of compromising every node in the network. We propose two verification schemes based on this framework, each designed for a particular deployment environment. We conduct an experimental evaluation of the verification schemes by using them to extend an existing fair scheduling scheme. The experimental results show that a fair scheduling scheme relying on the exchange of demand information can be extended by an instance of the verification framework to ensure misbehavior detection while incurring a relatively small amount of overhead. Misbehavior Resistant Fair Scheduling in Wireless Backhaul Mesh Networks by Varagur Karthik Iyer A thesis submitted to the Graduate Faculty of North Carolina State University in partial fullfillment of the requirements for the Degree of Master of Science