A Combined Rain and Cloud Attenuation Field Simulator and its Application to Gateway Diversity Analysis at Ka, Q and V bands

This contribution presents the benefits of using simulated spatially-correlated fields of tropospheric attenuation to predict the joint attenuation probability distributions underpinning the analysis of a site diversity system. The attenuation field is obtained by first combining three-dimensional rain rate and cloud fields so as to maintain their spatial correlation, and afterwards by simulating the interaction of the wireless system with the complete atmospheric environment. This approach allows a “real-time” combination of the attenuation induced by precipitation and clouds (in contrast to the summation of such contributions on statistical basis as currently recommended by ITU-R) which increases the model’s prediction accuracy and reliability. The paper investigates the gain achievable by multiple-site diversity schemes operating in the Ka and Q bands, for which the impairments due to clouds (not captured by the current ITU-R framework) become more important, in terms of required system wide margins and resulting link spectral efficiency.