By looking back to the history of wireless systems, one can reach the conclusion that the industry follows a ten-year cycle. First generation systems were introduced in 1981 followed by the deployment of second generation systems in 1991, ten years later. Moreover, third generation systems are due for deployment in 2001–2002. From the point of view of services, 1G systems offered only voice services, 2G systems also offered support for a primitive type of low-speed data services and 3G systems will enable a vast number of advanced voice and high-speed data services. The trend is towards support for even advanced. | Wireless Networks. P. Nicopolitidis M. S. Obaidat G. I. Papadimitriou and A. S. Pomportsis Copyright 2003 John Wiley Sons Ltd. ISBN 0-470-84529-5 6 Future Trends Fourth Generation 4G Systems and Beyond Introduction By looking back to the history of wireless systems one can reach the conclusion that the industry follows a ten-year cycle. First generation systems were introduced in 1981 followed by the deployment of second generation systems in 1991 ten years later. Moreover third generation systems are due for deployment in 2001-2002. From the point of view of services 1G systems offered only voice services 2G systems also offered support for a primitive type of low-speed data services and 3G systems will enable a vast number of advanced voice and high-speed data services. The trend is towards support for even advanced data services. 3G networks although having the advantage of support for IP and enhanced mobility will suffer from a divergence between several standards. This divergence will limit easy roaming between 3G networks based on different standards thus limiting user mobility. Furthermore 3G networks will have in the best case an upper capacity limit of 2 Mbps. Although more than enough for the application demands of the years to come 3G networks will most likely need to evolve in order to meet the mobile application demands of the next decades. As in all areas of technology the quest for better and more efficient systems never ends and as soon as the time for deployment of a system comes research on the next generation is usually under way. Consequently the imminent deployment of 3G systems is accompanied by initiation of research on the next generation of systems. If the ten-year cycle continues it is logical to expect that the next generation of wireless systems known as Fourth Generation 4G will reach deployment stage somewhere around 2010. As seen later in the chapter the vision for 4G and future systems is towards unification of various mobile and
