HANDING OFF A MOBILE STATION BETWEEN A FIRST ACCESS NETWORK SUPPORTING SIP (SESSION INITIATION PROTOCOL) AND A SECOND CELLULAR ACCESS NETWORK

摘要

The invention relates to a method, and device, a mobile station, a database and a mobile services switching center for the handover of calls in a telecommunications system comprising two access networks, a first access network supporting SIP (session initiation protocol), like a WLAN and a second, cellular access network. A demand to change from the first (WLAN) to the second (cellular) network is determined, a connection is set-up to the second network, and the connection to the first access network is released. A device supporting SIP and call control functionality for circuit switch is disclosed. A Data base is disclosed wherein two location identities associated to a mobile station are stored together with an indication on which is the preferred access network via which the mobile station should be reached. In addition, when routing a connection to a mobile station, information on a target mobile services switching centre will be extracted from a message received at an MSC and a paging will be suppressed.