UMTS-WLAN Interworking Strategies for Reducing Handover Delays

During handover between heterogeneous networks such as the 3G mobile telecommunication systems and the Wireless LAN systems, a subscriber authentication, the Mobile IP operations for IP mobility and an accessing to a data gateway are heavy burdens due to its time-taken operations and overheads. So they are main factors of handover delays. This paper proposes the handover strategies for reducing handover delays in the UMTS (Universal Mobile Telecommunications System) and the Wireless LAN overlay networks. For decreasing the delays, mandatory use of a fast re-authentication is applied and newly added features of one for the UMTS are introduced. And simplified MIPv6 operations and an optimized gateway approach to minimize the network access time are proposed. These proposed approaches are analyzed and evaluated with the results of an authentication test bed and a network simulation.