Research activities on UMTS radio interface, network architectures, and planning

Currently worldwide activities are going on to define third-generation mobile radio systems (IMT-2000 on ITU/UMTS in Europe). These systems aim to support a wide range of services from voice and low-rate data up to high-rate data services, including multimedia services, and circuit- and packet-oriented services. These systems will operate in all radio environments to provide service to anyone, anytime, anywhere. In Europe the European Commission is partly funding research activities in the ACTS framework related to third-generation systems. A spectrum-efficient multiple access scheme proposal is being developed by the ACTS FRAMES project to fulfill the requirements for terrestrial third-generation mobile radio systems. The results and proposals of FRAMES are used as input mainly to the ETSI standardization process. This radio access scheme addresses the different worldwide standardization activities where TDMA and CDMA-based solutions are currently expected. Different proposals for the UMTS system architecture and network issues are currently being discussed in the relevant standardization bodies. On one hand, the GRAN approach envisages a single UMTS access part able to connect with multiple core networks; on the other hand, the generic core network approach proposes to develop UMTS core network functionality able to handle multiple access networks, which can adopt different types of radio access techniques. The ACTS RAINBOW project presents a proposal where both approaches are unified in a system structure. From the network planning viewpoint, the major features of a third-generation mobile system are the wide variety of services provided, the high number of customers expected (especially in urban and densely populated areas), the network architecture flexibility to allow different configurations to be deployed, and the advanced mobility management strategies. From this perspective the ACTS STORMS project is elaborating new planning methodologies tailored to the specific needs of a UMTS operator, and designing and developing a set of software modules covering the whole set of disciplines involved in mobile network planning