IP for 3G - (P2)

An Introduction to 3G Networks IntroductionWhat exactly are 3G networks? 3G is short for Third Generation (Mobile System). Here is a quick run-down: † 1G, or first generation systems, were analogue and offered only a voice service – each country used a different system, in the UK TACS (Total Access Communications System) was introduced in 1980. 1G systems were not spectrally efficient, were very insecure against eavesdroppers, and offered no roaming possibilities (no use on holidays abroad.)....
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IP for 3G - (P2) IP for 3G: Networking Technologies for Mobile Communications Authored by Dave Wisely, Phil Eardley, Louise Burness Copyright q 2002 John Wiley & Sons, Ltd ISBNs: 0-471-48697-3 (Hardback); 0-470-84779-4 (Electronic) 2 An Introduction to 3G Networks2.1 Introduction What exactly are 3G networks? 3G is short for Third Generation (Mobile System). Here is a quick run-down: † 1G, or first generation systems, were analogue and offered only a voice service – each country used a different system, in the UK TACS (Total Access Communications System) was introduced in 1980. 1G systems were not spectrally efficient, were very insecure against eavesdroppers, and offered no roaming possibilities (no use on holidays abroad.). † 2G heralded a digital voice and messaging service, offered encrypted transmissions, and was more spectrally efficient that 1G. GSM (Global System for Mobile communication) has become the dominant 2G stan- dard and roaming is now possible between 1501 countries where GSM is deployed. † 3G – if the popular press is to be believed – will offer true broadband data: video on demand, videophones, and high bandwidth games will all be available soon. 3G systems differ from the second generation voice and text messaging services that everybody is familiar with in terms of both the bandwidth and data capabilities that they will offer. 3G systems are due to be rolled out across the globe between 2002 and 2006. 3G will use a new spectrum around 2 GHz, and the licences to operate 3G services in this spectrum have recently hit the headlines because of the huge amounts of money paid for licences by operators in the UK and Germany (£50 billion or so). Other countries have raised less or given away licences in so-called ‘beauty contests’ of potential operators [1]. 3G systems might be defined by: the type of air interface, the spectrum used, the bandwidths that the user sees, or the services offered. All have been used as 3G definitions at some point in time. In the first wave of deployment, there will be only two flavours of 3G – known as UMTS (developed and promoted by Europe and Japan) and cdma2000 (developed and promoted 22 AN INTRODUCTION TO 3G NETWORKS by North America). Both are tightly integrated systems that specify the entire system – from the air interface to the services offered. Although each has a different air interface and network design, they will offer users broadly the same services of voice, video, and fast Internet access. 3G (and indeed existing second generation systems such as GSM) systems can be divided very crudely into three (network) parts: the air interface, the radio access network, and the core network. The air interface is the technol- ogy of the radio hop from the terminal to the base station. The core network links the switches/routers together and extends to a gateway linking to the wider Internet or public fixed telephone network. The Radio Access Network (RAN) is the ‘glue’ that links the core network to the base stations and deals with most of the consequences of the terminal’s mobility. This chapter concerns the core and access networks of 3G systems – because that is where IP (a network protocol) could make a difference to the performance and architecture of a 3G network. The chapter first reviews the history of 3G developments – from their ‘conception’ in the late 1980s, through their birth in the late 1990s, to the teething troubles that they are currently experiencing. The history of 3G development shows that the concepts of 3G evolved significantly as the responsibility for its development moved from research to standardisation – shedding light on why 3G systems are deigned the way they are. Included in this section is also a ‘who’s who’ of the standards world – a very large number of groups, agencies, and fora have been, and still are, involved in the mobile industry. In the second half of the chapter, we introduce the architecture of UMTS (the European/Japanese 3G system) and look at how the main functional components – QoS, mobility management, se ...