Estimation of the repeater gain required for a wireless link

The question of repeater application arises very frequently in contemporary wireless and cellular communication systems. The paper is intended to show a basic methodology that allows us to estate the gain of antennas used in an active or passive repeater involved in a wireless link. Some key equations governing a link budget of the wireless link with repeaters are briefly described and the influence of the link range, its geometry and attenuation of the dominant obstacle on the repeater gain is discussed. The question concerning the use of passive repeaters is also addressed.