Recently, developed countries are leading in telecommunications technology, and many studies are being conducted to transmit information through the free space (FSO) or atmosphere using optical frequency light waves. The natural factors that most affect the propagation of optical light waves are fog, rain, and snow. Ulaanbaatar is the capital of Mongolia and has an extreme and variable climate. This paper is devoted to analyzing FSO link performance during data transmission in Ulaanbaatar during heavy rain months (July-August) and simulation using OptiSystem software. Marshall and Palmer's model was used for data transmission using FSO link performance to estimate the rainfall reduction, and several factors such as BER rate and Q factor were investigated. We have made a detailed assessment of the result of rainfall on the FSO system in Mongolia based on the technical data on the weather in Ulaanbaatar in 2018, 2019, and 2020 for the three meteorological station servers of the world weather online site www.worldweatheronline.com.
Rainfall, FSO, Q-factor, Rain Attenuation, Marshall-Palmer distribution
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