Analysis of the interference due to differential rain attenuation induced by an adjacent path on a triple-site diversity Earth-space system

The reliable design of satellite communication systems requires the consideration of interference effects. Interference caused by differential rain attenuation from an adjacent Earth-space system is taken under consideration. In particular, a method to predict rain differential attenuation statistics used for single/double site Earth-space systems is extended to include triple-site diversity ones. The modified method is again based on a model of convective rain cells as well as on the lognormal assumption for the point rainfall rate distribution at the location under consideration. In an analogous fashion with the (C/N) ratio, a "(C/I) diversity gain" is also adopted here and some very useful remarks concerning the effectiveness of the triple-site diversity protection as a countermeasure technique are deduced. As a general conclusion, it can be stated that the triple-site scheme not only reduce the potential large attenuation margins significantly, but also leads to the establishment of the minimum separation between satellites operating under permitted interference levels.