A Two-Phase Inter-Switch Handoff Scheme for Wireless ATM Networks

Supporting mobility in Wireless ATM networks poses a number of technical issues. An important issue is the ability to reroute on-going virtual connections during handoff as mobile users move among base stations. We propose a two-phase inter-switch handoff scheme using permanent virtual paths reserved between adjacent Mobility Enhanced Switches (MES). The virtual paths are used in the first phase to rapidly reroute user connections. In the second phase, a distributed optimization process is initiated to optimally reroute handoff connections. The proposed handoff scheme yields small handoff latency and optimal routes while decreasing system cost and complexity. The paper also describes wireless control and ATM signaling capabilities required for supporting this scheme. Specific ATM UNI/NNI protocol extensions are presented. Using analysis we calculate and study the bandwidth requirement for the reserved virtual paths. We also study the second-phase optimization process overhead as well as the effect of other system design parameters. 1

A framework for fast handoff schemes in wireless ATM networks

Includes bibliographical references.In this research, we focus on providing a framework that extends the fixed ATM standard to support user mobility in future WATM networks. The WATM architecture allows for the migration of fixed ATM networks without major modifications. Thus most of the mobility functions are implemented on the wireless access network. The most important component supporting mobility in a cluster is the Mobility Enhanced Switch (MES). We propose using direct links between adjacent MESs to support Permanent Virtual Channels (PVCs) in order to facilitate fast inter-cluster handoffwith minimum handofflatency. This research addresses a framework on handoff mobility by proposing three fast handoff re-routing schemes based on the support of PVCs