ARCHITECTURAL ASPECTS FOR THE EVOLUTION OF MOBILE COMMUNICATIONS TOWARD UMTS

The transition from second-to third-generation mobile systems and the evolution paths of the relevant radio/network configurations are drive n by technical and market considerations, In fact, these are affecting the standardization and research process ongoing at the regional leve l (ETSI, ACTS Program, U.S. Joint Technical Committee, Japanese ARIB) as well as the global level (ITU), The related discussion is becoming more and more meaningful for operators and manufacturers who are perce iving, on the one hand, the new perspectives associated with service, features, and bandwidth management evolution, and on the other hand, t he great impact that such an evolution could have on the existing mark et scenario and system development plans, In addition, due to the wide spread usage of GSM worldwide, this system should also be considered w ithin the evolution scenarios toward third generation, This paper anal yzes the situation emerging from the standards context, identifies som e key characteristics associated with current proposals, and tries to define a possible third-generation systems architecture based on the m ost encouraging propositions, e.g., the separation of radio-dependent and independent functions and the integration with B-ISDN, The paper r ationale and the identified solutions reflect the research activities within the ACTS project RAINBOW (radio access independent broad band o n wireless), addressing architectural solutions for UMTS (universal mo bile telecommunications system), the European developing standard for third-generation systems.