Prediction of Rain-Induced Attenuation Along Earth-Space Links at Millimetre Wave Bands over West African Region.

Abstract

The present work characterizes the degree of rain-induced attenuation on 15–80 GHz earth-space commu nication links. Eutelsats 36B and 36C, and NigComSat-1R satellite links over five West African countries were considered through the International Telecommunication Union Radiocommunication Sector (ITU-R) [International Telecommunications Union (ITU)], Bryant, and Syjatogor rain attenuation models. Three locations were selected in each country for the analysis using 2013–2017 rain data obtained from the Global Precipitation Measurement (GPM) missions. ITU-R predicted higher attenuation values than the other two models; while Svjatogor values were close to ITU-R, and the Bryant model predicted the lowest. At 99.99% signal availability, rain attenuation along the earth-space link over the five countries ranged between 22.1 and 34.2 dB for Ku-band (15 GHz) but exceeded the satellites’ link margins at Ka-band (30 GHz). At 0.1% unavailability, the range is 6–21 dB across all the locations for V-band (60 GHz), which implies that the satellites can sustain 99.9% of signal availability across the countries. However, for 99.99% and 99.9% sig nal availability at W-band, earth-space links can experience a total outage across the selected stations. Some locations in the northern parts can have 99% availability, which is an ~ 87 h/yr outage. Hence, the result could be a benchmark for planning trans-horizon radio communication links across West Africa