EVOLVING MOBILE NETWORKS While the history of mobile communications is long [1–3], and the background of mo bile networks therebyx is also long, in this chapter we focus on the historic evolution in terms of network architecture and services starting with 2nd generation (2G) mobile systems. In particular we consider the development of the architecture of Global Systems for Mobile Communications (GSM), since it is by far the most widespread mobile system in the world today. | The UMTS Network and Radio Access Technology Air Interface Techniques for Future Mobile Systems Jonathan P. Castro Copyright 2001 John Wiley Sons Ltd Print ISBN 0-471-81375-3 Online ISBN 0-470-84172-9 1 Evolving Mobile Networks While the history of mobile communications is long 1-3 and the background of mo bile networks therebyx is also long in this chapter we focus on the historic evolution in terms of network architecture and services starting with 2nd generation 2G mobile systems. In particular we consider the development of the architecture of Global Systems for Mobile Communications GSM since it is by far the most widespread mobile system in the world today. This will provide the basis to cover the introduction of Universal Mobile Telecommunication Services UMTS in relation to its Core Network CN and radio architectures. The latter will in turn serve as the platform to present UMTS Radio Access Technology which is one the aims of this book. The Growth of Mobile Communications Today wireless voice service is one of the most convenient and flexible means of modern communications. GSM technology has been at the leading edge of this wireless revolution. It is the technology of choice in over 120 countries and for more than 200 operators worldwide. Current estimates are that by the year 2001 there will be around 600 million wireless subscribers . mobile telephone users out of which more than 50 will depend on GSM technology. As the wireless revolution has been unfolding the Internet has also shown a phenomenal growth simultaneously. The advent of the World Wide Web and web browsers has propelled TCP IP protocols into the main stream and the Internet is widespread not Figure The growth of mobile and internet services. 2 The UMTS Network and Radio Access Technology only in the corporate environment but also in households. Large number of consumers have embraced the Internet and use it today to access information online for interactive business transactions
