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.