Comparison of Space-Polarization and Space-Frequency Diversities

The effective orders of diversity were measured and compared for quadruple "space-polarization" and "space-frequency\´ configurations over the 375-mile transhorizon tropospheric radio path between East Island, Puerto Rico, and Grand Turk Island, Grand Bahama Islands. For quadruple-diversity configurations and simultaneous operation over the same (four) radio paths, space-polarization diversity was found to be practically equivalent to dual diversity, while space-frequency diversity performance approached that of theoretical quadruple diversity. The difference in diversity performance between these two configurations is attributed to the relatively high cross-correlation coefficients between RF signals transmitted over spaced radio paths at the same frequency, compared to the same factor obtained from RF signals transmitted over the same paths but at two different frequencies.