TABLE OF CONTENTS In the beginning there were analogue mobile telephones; these were bulky, insecure and could only be used in a single country analogue mobile systems are often termed first generation (1G). Next came 2G digital systems, such as GSM, providing secure voice services and, with international standardisation, roaming to over 150 countries today. 2G mobile services are, however, restricted to voice, short messages and the ill-fated dial-up Internet access WAP (wireless application protocol) system. GSM has recently been upgraded to offer low bit rate (10 to 64 kbit/s) data services via GPRS (general packet radio service) the great advances of GPRS being that it can offer per-packet, as opposed to connection-time-based, charging as well as an always-on capability for data. Being always-on means that users are contactable in the data world, for example receiving e-mails and instant messages immediately.
The term third generation (3G) mobile system refers to a family of new air interfaces and access/core networks [1] examples being the European-backed UMTS and North American-backed CDMA2000 systems. These networks are beginning to offer users higher data rates, up to 384 kbit/s, better quality of service support for data, including real-time applications, e.g. video, and new applications, such as location-based services [2]. Within the industry and research communities, there is considerable debate about what form fourth generation (4G) mobile systems will take. In Japan [3] and the ITU [4], 4G has been proposed as a new air interface, probably based...
