Nature of space diversity in microwave communications via geostationary satellites: a review

Space diversity (the simultaneous use through a common operations centre of two, or more, satellite receivers on the ground to overcome severe path attenuation that might occur on one of the links) is a well known concept and many measurements have been made to assess its potential advantages. The experimental results to date, however, show a large variability in space-diversity performance. The paper reviews all the results known to the author, discusses the influence of various kinds of rainfall and analyses the principal causes giving rise to the variations in space-diversity performance. Microclimate, receiver base-line orientation, site separation and topography are concluded to be the prime causes of the variations in measured space-diversity performance, and broad guidance for selecting the sites for a space-diversity complex is given.