4g wireless technology
4g wireless technology.doc
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Pick up any newspaper today and it is a safe bet that you will find an article somewhere relating to mobile communications. If it is not in the technology section it will almost certainly be in the business section and relate to the increasing share prices of operators or equipment manufacturers, or acquisitions and take-overs thereof. Such is the pervasiveness of mobile communications that it is affecting virtually everyone’s life and has become a major political topic and a significant contributor to national gross domestic product (GDP).
The major driver to change in the mobile area in the last ten years has been the massive enabling implications of digital technology, both in digital signal processing and in service provision. The equivalent driver now, and in the next five years, will be the all pervasiveness of software in both networks and terminals. The digital revolution is well underway and we stand at the doorway to the software revolution. Accompanying these changes are societal developments involving the extensions in the use of mobiles. Starting out from speech-dominated services we are now experiencing massive growth in applications involving SMS (Short Message Service) together with the start of Internet applications using WAP (Wireless Application Protocol) and i-mode. The mobile phone has not only followed the watch, the calculator and the organiser as an essential personal accessory but has subsumed all of them. With the new Internet extensions it will also lead to a convergence of the PC, hi-fl and television and provide mobility to facilities previously only available on one network.
Limitations of 3G and Drivers for 4G
From its basic conception to the time of roll-out took around ten years for 2G; a similar period will apply to 3G, which will commence service in 2001/2 and reach full deployment by 2005. Thus by 2010 it will be time to deploy 4G networks and, working backwards with the ten year cycle, it is clear that the year 2000 is appropriate to start with visions for 4G and a research programme aimed at the key issues. The Mobile VCE’s second phase research programme has been constructed to meet this aim.
The starting point was to look at current trends. Here we see a phenomenal growth in mobiles with an estimated global user base that will exceed one billion by 2003. Already mobile communications exceed fixed communications in several countries and it is foreseen that mobile communications will subsume fixed by 2010 (fixed—mobile convergence will be complete). Currently short messaging is booming, especially among the younger generation, with averages of upwards of 100 messages per month dominating monthly bills. Business take-up of SMS via information services is also increasing and providing a start for mobile e-commerce, but this is currently very much limited by the bit rates available. This will be improved with the introduction of GPRS.
Analysis of the underlying technical challenges raised by the above vision and its five elements has produced three research areas: Networks and services, Software based systems, Wireless access. These form the basis of the Mobile VCE Phase 2 research programme.
Networks and Services
The aim of 3G is ‘to provide multimedia multirate mobile communications anytime and anywhere’, though this aim can only be partially met. It will be uneconomic to meet this requirement with cellular mobile radio only. 4G will extend the scenario to an all-IP network (access + core) that integrates broadcast, cellular, and cordless, WLAN (wireless local area network), short-range systems and fixed wire. The vision is of integration across these network—air interfaces and of a variety of radio environments on a common, flexible and expandable platform — a ‘network of networks’ with distinctive radio access connected to a seamless IP-based core network a (Fig. 4.1.1).
We have already seen in the previous subsection that to affect terminal and network node reconfigurability we need a middleware layer. This consists of network intelligence in the form of object-oriented distributed processing and supporting environments that offer the openness necessary to break down traditional boundaries to interoperability and uniform service provision. The mobile software agent approach is an especially important building block as it offers the ability to cope with the complexities of distributed systems. Such building blocks may reside at one time in the terminal and then in the network; or they may be composed of other objects that themselves are mobile. Within the mobile system there exists a range of objects whose naming, addressing and location are key new issues. A further step in this development is the application of the Web-service-model rather than the client/server principle; recent industry tendencies show a shift towards this paradigm and XML (extensible Markup Language) is seen as the technology of the future for Web-based distributed services. However this technology has yet to prove its scalability and suitability for future application in mobile networks.
It is always dangerous to predict too far ahead in a fast- moving field such as mobile communications. Almost by definition the eventual 2010 scene will not match exactly that depicted in the 4G vision described herein. However, the key elements—fully converged services, ubiquitous mobile access, diverse user devices, autonomous networks and software dependency—will persist. The 4G Vision is a living document which intends to update and amend as time and knowledge progress. It will act as the umbrella vision to a large research programme and place in context the detailed research work that will take place in the various areas. In this respect it will help to continuously steer the research as it progresses and, therefore, to make it more relevant and beneficial.