UMTS: The Fusion of Fixed and Mobile Networking

C ellular telecommunications technology is evolving from analog and digital mobile telephony systems into flexible voice-anddata systems that offer users complete global mobility. Systems based on analog transmission were termed first-generation systems and had limited capabilities. Second-generation systems are based on digital transmission and offer some advanced user services (see the sidebar on the next page, “Evolution of Cellular Systems”). The industry is now looking to the next generation of systems, which is expected to provide full personal and terminal mobility between dense metropolitan environments and sparsely populated regions around the globe. In Europe, the name given to the future third-generation system is the Universal Mobile Telecommunications System. This article introduces UMTS technology and looks at the choices facing system designers now and in the years ahead. To help negotiate the landscape of technical and regulatory acronyms that accompany this story, see the sidebar, “Mobile Telecommunications Glossary.”