Handoff Management Schemes in Wireless Mesh Networks
Recent advances in Wireless Mesh Networks (WMNs) have overcome the drawbacks of traditional wired networks and wireless ad hoc networks. WMNs will play a leading role in the next generation of networks, and the question of how to provide smooth mobility for WMNs is the driving force behind the research. The inherent characteristics of WMNs, such as relatively static backbones and highly mobile clients, require new handoff management solutions to be designed and implemented. This thesis first presents our research work on handoff management schemes in traditional WMNs. In general, a handoff process includes two parts, the MAC layer handoff and the network layer handoff. For the MAC layer handoff, a self-configured handoff scheme with dynamic adaptation is presented. Before the mobile node starts the probe process, it configures parameters for each channel to optimize the scan process. Moreover, a fast authentication scheme to reduce authentication latency for WiFi-based mesh networks is introduced. A tunnel is introduced to forward data packets between the new access router and the original reliable access router to recover data communication before the complete authentication process is finished. To minimize the network layer handoff latency, a hybrid routing protocol for forwarding packets is proposed: this involves both the link layer routing and the network layer routing. Based on the hybrid routing protocol, both intra-domain and inter-domain handoff management have been designed to support smooth roaming in WMNs. In addition, we extend our work to Vehicular Mesh Networks (VMNs). Considering the characteristics of VMNs, a fast handoff scheme is introduced to reduce handoff latency by using a multi-hop clustering algorithm. Using this scheme, vehicle nodes are divided into different multi-hop clusters according to the relative mobility. Some vehicle nodes are selected as assistant nodes; and these assistant nodes will help the cluster head node to determine the next access router for minimizing handoff latency. Extensive simulation results demonstrate that the proposed scheme can reduce handoff latency significantly.
Handoff, Wireless Mesh Networks, Smooth roaming
Networked Digital Library of Theses and Dissertations
Université d'Ottawa / University of Ottawa