A subscriber signalling gateway between CDMA mobile station and GSM mobile switching center

A new multiple access scheme called CDMA offers the increased capacity due to the efficient frequency reuse and the exploitation of speech activity. It is to be very attractive for various mobile and personal communications. On the other hand, CCITT PLMN or ETSI GSM is expected to be adopted widely by many PTTs because it may cover wide area and provide speedy and efficient mobility managements such as location update, handover, authentication, etc., by means of the well-established CCITT Common Channel Signalling System No.7 (CCS#7). However, no attempts to bridge these two promising technologies have been reported yet in the literature. This paper introduces a subscriber signalling gateway which resides in a Base Station (BS) and converts signalling messages bidirectionally between the Qualcomm´s CDMA CAI (Common Air Interface) based MS and the GSM SS (Subscriber Signalling) based MSC. The layer 3 functions of the gateway consist of three functional components: CDMA-RR/GSM-RR converter for handover (handoff) handling, CDMA-MM/GSM-MM converter for location update (registration) handling, and CDMA-CC/GSM-CC converter for call setup and clearing. Interworking scenarios and functions of these converters are discussed. Furthermore message flow examples for location update, handover, and call control are presented. The successful interworking of these technologies will graft these two promising technologies so that the advantages of them could be provided throughout the mobile communication network