Overview of Mobile Networks
1.1 INTRODUCTION Mobile networks are differentiated from each other by the word 'generation', such as 'first-generation, 'second-generation' etc. This is quite appropriate because there is a big 'generation gap' between the technologies. The first-generation mobile systems were the analogue (or semi-analogue) systems, which came in the early 1980s - they were alsocalled NMT (Nordic Mobile Telephone). They offered mainly speech and related services and were highly incompatible with each other. Thus, their main limitations were the limited services offered and incompatibility. The increasing necessity for a system catering for mobile communication needs, and offering more compatibility, resulted in the birth of the second-generation mobile systems.International bodies played a key role in evolving a system that would provide better services and be more transparent and compatible to networks globally. Unfortunately these secondgeneration network standards could not fulfil the dream of having just one set of standards for global networks. The standards in Europe differed from those in Japan and those in America, and so on. Of all the standards, theGSM went the furthest in fulfilling technical and commercial expectations. But, again, none of the standards in the second generation was able to fulfil the globalisation dream of the standardisation bodies. This would be fulfilled by the third-generation mobile systems. It is expected that these third-generation systems will be predominantly oriented towards data traffic, compared with thesecond-generation networks that were carrying predominantly voice traffic. The major standardisation bodies that play an important role in defining the specifications for the mobile technology are:
Fundamentals of Cellular Network Planning & Optimisation A.R. Mishra. © 2004 John Wiley & Sons, Ltd. ISBN: 0-470-86267-X
OVER VIEW OF MOBILE NETWORKS
ITU (International Telecommunication Union):The ITU, with headquarters in Geneva, Switzerland, is an international organisation within the United Nations, where governments and the private sector coordinate global telecom networks and services. The ITU-T is one of the three sectors of ITU and produces the quality standards covering all the fields of telecommunications. ETSI (European Telecommunication Standard Institute): This body wasprimarily responsible for the development of the specifications for the GSM. Owing to the technical and commercial success of the GSM, this body will also play an important role in the development of third-generation mobile systems. ETSI mainly develops the telecommunication standards throughout Europe and beyond. ARIB (Alliance of Radio Industries and Business): This body is predominant in theAustralasian region and is playing an important role in the development of third-generation mobile systems. ARIB basically serves as a standards developing organisation for radio technology. ANSI (American National Standards Institute): ANSI currently provides a forum for over 270 ANSI-accredited standards developers representing approximately 200 distinct organisations in the private and publicsectors. This body has been responsible for the standards development for the American networks. 3GPP (Third Generation Partnership Project): This body was created to maintain overall control of the specification design and process for third-generation networks. The result of the 3GPP work is a complete set of specifications that will maintain the global nature of the 3G networks.
1.2 MOBILE NETWORKEVOLUTION Mobile network evolution has been categorised into 'generations' as shown in Figure 1.1. A brief overview on each generation is given below.
Figure 1.1 Evolution of mobile networks
MOBILE NETWORK EVOLUTION
The First-generation System (Analogue)
The first-generation mobile system started in the 1980s was based on analogue transmission techniques. At that time,...