GSM-interoperable mobile satellite call processing architecture

The future mobile network infrastructure will be comprised of a variety of wireless access networks. The networks will not necessarily work the same way. Modulation, coding, error control, access control, and radio resource management protocols will likely differ for the various access technologies. These networks will, however, be capable of interoperating with the whole set of disparate networks in the areas of mobility management and call control. Mobile satellite (MSAT) networks, as they have only recently emerged upon the scene, are forced by evolutionary circumstances to adapt to existing industry standards for transmission interfaces to public networks, as well as standard signaling procedures for network call control and mobility management. The European Global System for Mobile Communications (GSM) specifications define an elegant system with a well-conceived mobility management scheme that will likely survive in someform as a public standard, and it is viewed that MSATnetworks must adapt to this scheme. MSAT network designers have been prone to meet this challenge by choosing a GSM interface or GSM network element (e.g., the Mobile Services Switching Center (MSQ), to act as a design constraint around which the MSATnetwork isfashioned. This paper explains why such an approach does not work well. The paper also offers a unique architectural solution that is consistent both with the functional models upon which GSM is based, and with the physical attributes of an MSAT network. The architecture is formed through the decomposition of the MSC into two distinctfunctional elements, which operate in conjunction to perform the logicalfunctions of an MSC.