ABSTRACT
Wireless communication networks provide telephone service to mobile users have been rapidly developed since 1980s. Beginning with the first generation analog systems, which provided voice service, systems have developed to the standardization of third generation systems which will have the capability to offer multimedia services. The most fundamental concepts in the development of economically viable wireless telecommunication networks are the concepts of frequency re-use and accurate transmitter power control which allows the use of a relatively small amount of radio spectrum to serve a large population of mobile users in some population area such as a city. The key issue in the development of these systems has been the maximization of the capacity of the system in terms of the number of users that can be served per base station per unit of bandwidth. Due to the limitation in technology the first generation systems were analog and as a result of propagation impairments they used a relatively inefficient modulation technique – wideband FM. As a result of the rapid success of these systems there was a strong push for the design of second generation systems. The main objective for this development in North America was the capacity issue – where the capacity limit of the early systems was quickly reached in cities such as Chicago and Los Angeles. A goal of 10 times the capacity of the analog system was set for the second generation systems in North America. These systems also had to maintain downward compatibility with the analog system. In Europe the second generation systems were motivated by the need to develop a pan-European system which would work with the same hand terminal in all the countries of Europe. The second generation system was also designed to operate in a new frequency band – hence downward compatibility with the older first generation systems was not necessary.
