Measurement Analysis of Amplitude Scintillation for Terrestrial Line-of-Sight Links at 42 GHz

Abstract

Tropospheric scintillation is a rapid fluctuation of the signal amplitude and phase due to irregularities in the refractive index caused by atmospheric turbulence. If not considered properly, amplitude scintillation may affect the performance of a low-power margin communication system. In this paper we study the amplitude scintillation observed on three converging terrestrial 42 GHz links. Probability density functions of amplitude scintillation for different seasons of a year are presented. In addition, the cumulative distributions of the dry and wet amplitude scintillation are shown. The measured long-term probability density functions of the three links are compared with the Moulsley-Vilar model. The results show that for small values of amplitude scintillation the Moulsley-Vilar model fits well the measured statistics, but overestimates the statistics for large values of amplitude scintillation. Good agreements are found between the Gaussian model and the measured short-term amplitude scintillation distributions. In addition, the link diversity of amplitude scintillation over combinations of two and three links are presented. Furthermore, the monthly average wet component of refractivity has been calculated using meteorological measurements, and as expected it shows a peak during the summer time.