Proactive context transfer and forced handover in IEEE 802.11 wireless LAN based access networks

Abstract

In recent years, many protocols have been developed to support user mobility in wireless networks, e.g. Mobile IP suite of protocols designed to support IP routing to mobile nodes. However, support for truly seamless mobility requires more than just routing: every service associated with the mobile user needs to be transferred smoothly to the new access network. In this paper, we will concentrate on the problem of transferring service state (context) at both the link and the IP layers. We propose a method to estimate the best moment in time for transferring context information associated with the mobile user. As one of key issues in the proactive context transfer scheme is accuracy of handover prediction, we suggest and describe a new concept of Forced Handover that can provide very low handover latency. The simulation results and the following discussions show that our scheme is helpful in ensuring seamless mobility, while keeping the number of unnecessary handovers resulting from the proactive nature of the scheme at a controllable level.