10 - Cellular telecommunications

Abstract

Cellular telecommunications have evolved significantly since its inception. The chapter examines the three generations of system, generally known as 1G, 2G, and 3G to denote the different generations. The basic concept around which cellular telecommunications operates is that the coverage area is split up into small areas called cells. Each one is covered by a relatively low power base station. This has advantages over the earliest concepts used by relatively high power mobile phones where a single high power station was used to provide coverage over a large area. The cell system enables local area coverage using low power handsets so that at a certain distance away, the frequencies can be reused. Interference is kept to a minimum by the fact that adjacent cells use different frequencies or channels, although a different technique is used for a CDMA system. By arranging that the mobile handset is able to change from one of the channels supported by one cell to one of the channels supported by the adjacent one, virtually seamless coverage can be achieved. Although this creates additional complexity in the base station and handset, it enables much greater use to be made of the available channels.