| 摘要 |
A mobile handset is capable of establishing communication through a cellular network (2) and a local access system (7, 8, 27), which has an interface (9) with the cellular network to allow the handset's presence to be logged by the switching centre of the cellular system (2). If the handset requires a handover between local access systems (7, 27), this is provided for by a handover processor (97) in the interface (9), instead of in the mobile switching centre (2). This allows the connection between the mobile access bridge (9) and the mobile switching centre (2) to remain unchanged, and sessions are still routed by the mobile switching centre (2) to the mobile access bridge (9), which emulates a base site controller. Thus, in the event that a handset makes such a transition, the mobile switching centre (2) has no visibility of that handover, and the same network identity can be used for the handset (1), by way of the mobile access bridge (9), throughout the time the handset is connected to the local wireless connections rather than directly to the cellular network through a base station (21). This allows network facilities that are only available through the access networks (7, 27), but not through the cellular system (2), to be maintained seamlessly during the handover.
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