Third-generation mobile network architectures for the universal mobile telecommunications system (UMTS)

Mobile telecommunications is the fastest growing sector of the telecommunications industry, with second-generation systems being implemented with great success all over the world. Spectrum limitations and various technical limitations of second-generation systems have led some regions to develop concepts for a third-generation mobile system. Planned to begin operation at the start of the next millennium, third-generation systems are currently the subject of research and development and standardization by the International Telecommunication Union (ITU) and regional standards bodies. This paper addresses the market for third-generation services and several technical issues of network architectures for the Universal Mobile Telecommunications System (UMTS). We place particular emphasis on the collaborative research activity conducted in Europe since 1988, funded by the European Commission. One of their major research projects is Radio Independent Broadband on Wireless (RAINBOW), which is investigating the feasibility of a UMTS network infrastructure based on the concept of radio dependence/independence. This UMTS network infrastructure can support both second- and third-generation multiple air interface standards. Lucent is a major partner in this collaborative research effort, providing the Global System for Mobile Communications (GSM) radio interconnection to the asynchronous transfer mode (ATM)-based network infrastructure of the RAINBOW demonstrator.