Siemens Mobile Communications S.p.a.

Marco Berra

Stefano Sartorelli

A station controller (M-BSC) is connected to base transceiver stations BTS of the GSM (Global System for Mobile), or DCS (Digital Cellular System) mobile transceiver system, and to BTSC base transceiver stations of the TD-SCDMA (Time Division Synchronous Code Division Multiple Access) system through code division transceiver access technology, typical of 3G systems, and TDD duplexing. The controller is connected to a MSC circuit switch of GSM type. The new 3G technology shares the GSM core network, which on the contrary ignores the existence of the latter. Transparency of the 3G new technology towards the core network is achieved inhibiting any handover from GSM cells to BTSC cells and enabling the external handover (through MSC intervention) from BTSC cells to GSM cells after appropriate treatment of information to be sent to MSC. The ad hoc procedure is carried out by the station controller and consists in reprocessing the mixed list (2G and 3G) of cells candidate for handover furnished with by BTSC, to obtain two lists of cells differing as to radio technology, selecting a list to be forwarded to MSC according to service qualification criteria, comparing in a local memory the (MS/UE) mobile classmarks owned by MSC with those associated to the selected list and, in case of inconsistency, updating MSC classmarks prior to the forwarding of the selected list.

Controller for GSM and 3G base transceiver stations in a GSM core network with external handover possibility from 3G cells to GSM cells transparent to GSM core network

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Mesero, Italy

Marco Berra