Fast handoff scheme based on mobility prediction in public wireless LAN systems

Recently, wireless LAN systems have been widely deployed for public mobile Internet services. Public wireless LAN systems can provide high speed Internet connectivity using portable devices such as laptop computers, personal digital assistants (PDAs), etc. In public wireless LAN systems, reliable user authentication and mobility support are essential issues. However, re-authentication during handoff procedures causes long handoff latency and this affects the quality of service in real-time multimedia applications. A fast handoff scheme based on mobility prediction is proposed. In this scheme, a mobile host entering the area covered by an access point (AP) performs authentication procedures for multiple APs, rather than just the current AP. These multiple APs are selected by a prediction method called the frequent handoff region (FHR) selection algorithm, which takes into account users' mobility patterns, service classes, etc. Since a mobile host is registered and authenticated for an FHR in advance, handoff latency resulting from re-authentication can be significantly reduced. Simulation results show that the proposed scheme is more efficient than other schemes in terms of handoff delay and buffer requirements.