PREDICTION OF ORBITAL DIVERSITY PERFORMANCE IN SATELLITE COMMUNICATION-SYSTEMS AFFECTED BY RAIN ATTENUATION

We have extended the two-layer rain model to predict the gain of any o rbital diversity system, defined as the difference between the attenua tion (dB) in a single link and the attenuation (dB) in the diversity l ink, both exceeded with the same long-term probability. Besides the ob vious geographical data of the site, the geometry of the system and th e frequency and polarization of the electromagnetic waves, the only ph ysical input is a meteorological quantity, i.e. the probability distri bution of rain rate. We have tested the model against experimental dat a in the 12 GHz and 20 GHz bands, collected at two sites in Italy. The agreement between measured and predicted gain is satisfactory up to a ttenuation values for which a significant sample size is ensured. (C) 1997 by John Wiley & Sons, Ltd.