Evaluation of Wireless Mesh Network Handoff Approaches for Public Safety and Disaster Recovery Networks

In public safety and disaster recovery (PSDR) scenarios, reliable communication is an imperative. Unfortunately, communication infrastructure is often destroyed or overwhelmed by whatever precipitated the scenario (e.g., a hurricane or terrorist attack). Thus, the PSDR workers must often deploy their own communications infrastructure on-site. Wireless mesh networks (WMN) have been identified as being ideally suited to this task. WMN offer a high-capacity wireless backhaul network, provided by mesh routers, through which clients can connect to one another or with external networks. Mobility of clients within the mesh is particularly important for public service and disaster recovery scenarios. This creates a challenging problem as clients may move out of range of the mesh router they were using to connect to the mesh and need to associate with another. Client handoff mechanisms provide this functionality. In this paper we provide a critical survey of client handoff approaches applicable to IEEE 802.11 WMN evaluating them based on the strict QoS requirements established by the US Department of Homeland Security for PSDR networks.