Mobile communication networks were commercially launched as Circuit-Switched (CS) systems centering on speech communication services. The First-Generation (1G) analog system evolved into the Second-Generation (2G) digital system, followed by the introduction of Packet-Switched (PS) communication system. These conventional mobile communication systems were realized with different technologies by country and region, and there was no internationally unified standard. | W-CDMA Mobile Communications System. Edited by Keiji Tachikawa Copyright 2002 John Wiley Sons Ltd. ISBN 0-470-84761-1 4 Network Technologies Makoto Furukawa Hiroshi Kawakami Mutsumaru Miki Daisuke Igarashi Yukichi Saito Toyota Nishi Mayuko Shimokawa Katsumi Kobayashi Yasuhiko Kokubun and Masayuki Nakanishi Overview Mobile communication networks were commercially launched as Circuit-Switched CS systems centering on speech communication services. The First-Generation 1G analog system evolved into the Second-Generation 2G digital system followed by the introduction of Packet-Switched PS communication system. These conventional mobile communication systems were realized with different technologies by country and region and there was no internationally unified standard. The standardization and system development of the Third-Generation 3G International Mobile Telecommunications-2000 IMT-2000 was instigated in response to meet the increasing need to accomplish high-speed data communications adequate for mobile multimedia services and to develop a global system that would allow mobile terminals to be used worldwide. IMT-2000 is standardized on the basis of two regional standard development groups namely 3GPP and 3GPP2 3rd Generation Partnership Projects . This chapter reviews the network technologies with reference to 3GPP which adopts Wideband Code Division Multiple Access W-CDMA for the Radio Access Network RAN and an evolved Global System for Mobile Communications GSM Core Network CNs for CN systems. Figure illustrates the reference model for the CN architecture specified by 3GPP 11 . The functional entities inside CN more or less correspond to the functions in the Personal Digital Cellular PDC model referred to in Chapter 1. The signaling method of CN under 3GPP is based on GSM and General Packet Radio Service GPRS which are used for 2G mobile communication systems worldwide with some newly added functionality and capabilities to meet IMT-2000 requirements. As
