Performance Estimation for 15-GHz Microwave Links as a Function of Rain Attenuation

In this concise paper we present a method to estimate the performance of wide-band 15-GHz microwave line-of-sight communication links as a function of precipitation statistics, given specific fade margins derived from equipment and path parameters. The method is based on the use of theoretical or measured rain attenuation rates, statistics of surface point rainfall rates, and relations between point and path-average rainfall rates derived from measurements in Florida. Results in terms of total path attenuation or maximum usable path lengths for given performance criteria can vary widely depending on the data base used; they are particularly sensitive to the attenuation rate model used and to the rain climate. As a practical matter, the analysis shows that path lengths up to about 30 km for line-line-of-sight links (with adequate terrain clearance) may be usable in climates characterized by moderate rainfall amounts (such as central Europe) even if relatively pessimistic assumptions are made regarding rain attenuation rates.