Cellular Phone Base Stations: Technology & Exposures

The principles and practice of cellular radio systems for mobile communications are presented using GSM 1800 as a reference system. In particular, the concepts of small cells and frequency re-use and the components of radio base station technology are described. Public and cellular broadcasting have been widely available for many years and a brief history is given to indicate length of exposure from these sources. National and international guidelines for safe exposure to non-ionising radiation are used hy cellular operators to define exclusion zones around transmitting antennas. A methodology for calculating an exclusion zone is described, together with an example for a typical antenna configuration. Estimated levels of exposure near practical base stations are given and comparisons made with other sources of rf radiation. Finally, the digital nature of today's cellular radio systems, such as GSM, are explained and the implications described.