Availability Assessment of Free-Space-Optics Links With Rain Data From Tropical Climates

Abstract

Rainfall in tropical environments acts as a dominant parameter for estimating the availability of free-space optics (FSO). Long fades are caused by precipitation in particular heavy rains, and this precipitation increases atmospheric attenuation due to rain and reduces the availability of optical power from FSO links. In this paper, the link availability of an FSO system is estimated under the impact of rain in a tropical climate. The influence of rain on the propagation of FSO signal is investigated based on experimental and statistical analyses of rain-rate measurements under tropical conditions. Rain-rate data are measured in Malaysia for three years and used to estimate the availability of FSO links. Models developed in Malaysia are used to predict atmospheric attenuation due to rain. Long-term statistical measurements of rain data can enable good estimation of link availability. Based on the prediction model and measured rain-rate data, the FSO link budget is analyzed, and the link availability as a function of distance is predicted. Carrier class availability limits the FSO link to a few hundred meters only, whereas enterprise class availability can exceed FSO links over a few kilometers long. © 1983-2012 IEEE.

Availability modelling of terrestrial hybrid FSO/RF based on weather statistics from tropical region

“…Haze attenuation statistics are presented in [26]. The attenuation was predicted based on 3 years of measured visibility data in Malaysia, whereas FSO rain attenuation statistics is presented in [31]. The RF rain attenuation prediction is demonstrated in this paper using the measured rain rate in [31].…”

“…The attenuation was predicted based on 3 years of measured visibility data in Malaysia, whereas FSO rain attenuation statistics is presented in [31]. The RF rain attenuation prediction is demonstrated in this paper using the measured rain rate in [31]. The total path rain attenuation exceeding 0.01% of the time for RF can be estimated using the following ITU-R model [32]:…”

Performance analysis of free space optical communication system under rain weather conditions: a case study for inland and coastal locations of India

“…Moreover, heavy rainfall can lead to unavailability of FSOC links also. The scattering caused by rainfall is called non-selective scattering and it is independent of wavelength as radius of rain drops (100-1000 µm) is more than the wavelength used for FSOC links (Basahel et al 2017). Systems operating at frequencies below than 10 GHz are not attenuated by atmospheric weather conditions.…”

Availability Prediction Methods for Terrestrial Free-Space-Optical Link Under Tropical Climate

“…Availability prediction model is varying from one region to another. Each region derives its model which best represent its region and fit with its local weather data.For example, in a tropical climate, rain is the most constant factor that occurs most of the year [10]. Normal haze also be considered as a parameter that influences the optical signal [11]- [12].…”

“…The link availability can be obtained if the received optical power does not exceed the specific receiver sensitivity for the required link distance. Availabilities of the FSO link due to rain are calculated by using CDF of the predicted rain attenuation in [10]. Geometrical loss is predicted using (5) for FSO system parameters presented in Table 1; whereas optical loss assumed to be 4 dB.…”