IP based network controlled handover management in WLAN access networks

The purpose of this article is to present the different approaches for mobility management within all-IP cellular access networks based on wireless LAN (WLAN) technologies and to propose an innovative approach where handover is controlled by the network which provides target attachment point selection during handovers. This article describes mobility features supported by emerging WLAN technologies as well as mobile IP protocol and enhancements considered in IETF for improving local mobility and handover speed. By analysing the limitations of current mobility management approaches for IP radio access networks based on WLAN technologies, it introduces motivations for a network-controlled mobility management solution consisting of the close integration of WLAN and IP mobility features. Finally, it proposes that such a network-controlled approach can be developed as an extension to the existing hierarchical mobile IPv6 protocol, relying on the implementation of a new network function dedicated to the control of user terminal mobility. This proposal has been validated in a complete test platform and the given experimental and simulation results confirm the gain of such a mobility management in terms of handover efficiency as delays are reduced to a value closed to the radio layer one.