CHARACTERIZATION OF RAIN ATTENUATION AND ITS APPLICATION TO TERRESTRIAL COMMUNICATION SYSTEMS IN SOUTH AFRICA

摘要

The characteristics of rain attenuation for terrestrial communication system design for 3 different geographical locations in South Africa are investigated in this paper. These locations are chosen for study because of their unique climatic features which contributes significantly to their propagation behavioral patterns. These locations are Durban which lies in the coastal region, Cape Town in the mediterranean region and Pretoria which is situated in a temperate climatic environment in South Africa. In this work, a 5-year locally observed rain rate data (2000-2004) in these geographical locations with a 1-year signal attenuation level measurement recorded in Durban (2004) for a 6.73 km horizontally polarized 19.5 GHz terrestrial link has been utilized. Using the ITU-R rain attenuation model on the available rain rate data, the monthly cumulative distributions of rain attenuation averaged over a period of 5 years and the average attenuation distributions over the entire 5 years are estimated in each of these locations. From these distributions, appropriate figures of fade margin are derived for various percentage of link availability. Which when applied to a communication link design, give the necessary allowance needed on a terrestrial link to accommodate any impairment that may occur due to rain.