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.