| 摘要 |
A moveable switching system provides a cell, or small network of cells, which moves with the aircaft or other vehicle on which it is located, but whose operation appears to the user as an ordinary fixed base station of the "host" network to which it is connected. A cellular mobile switching centre (16), on board the aircraft, detects a call attempt or registration attempt from a mobile unit (10) and generates a temporary onboard identity for association with the mobile identity code. The temporary onboard identity code is associated with a node of the onboard part of a satellite communications system. The code is returned to the onboard MSC (16) which sets up a call over a satellite system (13, 6, 3) to the MSC (41) of a host network (4). When such a call is received from the satellite ground station (3) the host MSC (41) routes the call to an interface unit (48) which retrieves the identities of the cellular telephone and the onboard terminal. The cellular identity is passed to a network registration unit (45) to allow a location update to allow calls to the cellular telephone (10) to be routed to the mobile station (41). Consequently, any incoming calls intented for the mobile user will now be directed to the network (4), as the mobile user is currently registered there. The interface unit (48) also passes the temporary onboard identity code to a call diversion instruction unit (46), which generates a "divert on busy" instruction to the VLR 44 (step 615). This causes any calls for the cellular telephone (10) received by the host MSC 41 to be diverted via the satellite link (3, 6, 13) to the node indicated by the temporary onboard identity code, where the call is routed to the onboard MSC (16) and the code re-translated back to the cellular identity code to allow connection to the cellular telephone (10).
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