Overwater line-of-sight fade and diversity measurements at 37 GHz

The results of line-of-sight propagation measurements at 37 GHz over a 10.0-mile overwater test site are presented. Measurements of the short-term fading statistics, and of the time, space, and frequency diversity parameters are included. Strong negative correlation was observed during both the space and frequency diversity measurements; negative correlation coefficients were as large as -0.8. The diversity improvement obtained was greater than the value expected from correlation calculations, which is attributed to the consistent occurrence of negative correlation in the vicinity of the interference nulls rather than the random occurrence assumed in the calculations. For the optimum case where maximum negative correlation occurs, sufficient diversity improvement is achieved with either space or frequency diversity to permit the elimination of almost the entire fade margin that is needed to overcome the multipath fading associated with reflections from the water surface.