ach 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 also called 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 second- generation 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, the GSM went the furthest in fulfilling technical and commercial expectations. But, again, none of the standards in the second generation was able to fulfil the globali- sation 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 the second-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 OVERVIEW OF MOBILE NETWORKS ITU (International Telecommunication Union): The ITU, with headquarters in Geneva, Switzerland, is an international organisation within the United Nations, where govern- ments and the private sect