Mobility Management in Wireless Networks

Abstract

This dissertation discusses mobility management in IP based wireless environments. Mobility management can include both handovers within one technology and selection of access technology in a heterogeneous overlapping environment. IETF has standardized Mobile IP and its IPv6 version for handling mobility management in the IP networks. Even though Mobile IPv6 handles mobility in an application transparent way, several unresolved problems remain. This dissertation focuses on minimizing the Mobile IPv6 handover delays and interface selection in heterogeneous wireless environments.An enhancement called Flow-based Fast Handover for Mobile IPv6 is presented for speeding up the Mobile IPv6 address registration phase. The address registration phase, and thus also packet loss, can be notably decreased. More importantly, the delay is not dependent on the distance of the Corresponding Nodes as is the case with Mobile IPv6. In addition, mechanisms to control Mobile IPv6 handovers to offer the users and applications a best access were researched. Real time information about the link status and quality as well as user preferences are taken into account in the interface selection. The objective is to offer an Always Best Connected access to the user, and seamless handovers.