Depolarisation due to rain: the XPD-CPA relation

Theoretically as well as empirically, it has been shown that there is a certain correlation between depolarisation and attenuation due to rain. This relation provides a practical prediction tool for depolarisation. Using, for example, an equiprobability relation, depolarisation statistics may be derived from attenuation statistics. Furthermore, combined statistics of depolarisation and attenuation can be used to assess the margins of both parameters required for a certain system outage probability. Several theoretical and semi-empirical models for the relation between cross polarisation discrimination (XPD) and copolar attenuation (CPA) have been published, as well as many measurement results of this relation. In this paper, a large group of measurement results is used to assess all different dependencies of this relation empirically.