Evolution phases integrating satellite and terrestrial networks in the configuration of S-UMTS

S-UMTS assumes the role of a new generation global system for mobile communications. This paper proposes a possible structure of S-UMTS and discusses steps towards the final architecture. A smooth migration process is suggested resulting in a system with all requested new features which is compatible and involves almost all, previous generation, terrestrial and satellite systems. The first step foresees the interworking of todays operable systems achievable by introducing interworking units (IWUs) which connect the regarded systems and provide some of the needed features. The next step involves introduction of new elements, which should work together with the previous generation systems. By adding elements, in the further steps, the new S-UMTS system becomes independent of the "old" generation systems. However, a complete usage of the previous systems will be sustained. The users will have the possibility to get new services, but also to remain in their "old" systems. In both cases a connection with every single part of any of the "old" or "new" generation networks is possible.