Estimation of cell area coverage and cell-site diversity gain in 30 GHz fixed cellular systems under rainy conditions

The research reported in this thesis was aimed at examining the effects of rain attenuation on cell area coverage and the feasibility of applying cell-site diversity in such cellular systems. The study was conducted by simulating circular radio cells on images of radar-measured reflectivity factors, from which statistics of rain attenuation at 30 GHz and area coverage were derived.; Initial stages of this research were dedicated to derivation of an appropriate set of parameters of the power-law relationship between specific attenuation and radar reflectivity factor to be used later in radar data processing. Examination of a large number of raindrop size measurements made in Montreal and Toronto using JWD (Joss-Waldvogel Disdrometer) and POSS (Precipitation Occurrence Sensor System) was emphasised on the effects of inaccuracies in small-sized drops detection by these instruments on the derived relation between specific attenuation and reflectivity factor. The resulting power-law coefficients from this study show some differences compared to those recommended by the ITU-R, which are the smallest for frequencies around 20–30 GHz. A further study showed that the statistics of rain attenuation on a radio link computed using the power-law resolution is resistant to spatial averaging.; Analysis of cell area coverage under rain with uniformly LOS (line-of-sight) links in the cell area indicated that rain attenuation varies spatially and that the coverage statistics are non-linearly dependent on the cell radius.; Evaluation of average angular correlation function of attenuation on two converging links indicated that cell-site diversity is potentially beneficial especially in heavy rains, even when the two hubs involved are not located in the exactly opposite directions with respect to the position of the subscriber terminal. Detailed evaluation of angular diversity gain of two diversity links with selection combining showed dependence on angular separation &thetas; in a general form of sink(&thetas;/2). The model reduces to an approximately root-sinusoidal form (k = 0.5) when both diversity links are of equal length. (Abstract shortened by UMI.)...