A Two-Phase Handoff Scheme for Mobility Management in Wireless ATM Networks

Abstract

Mobility management in Wireless ATM networks poses a number of technical issues. An important issue is the ability to manage and reroute on-going connections during handoff as mobile users move among base stations. We propose a two- phase handoff management 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 handed-off connections. The paper also describes an adaptive optimization scheme to achieve high reserved bandwidth utilization. We analytically calculate and study the bandwidth requirement for the reserved virtual paths and handoff blocking probability. We also study the impact of processing and signaling load due to the second-phase route optimization. Both ATM CBR and VBR traffic types were considered for mobile users