Comparison of Different Models for Ground-Level Atmospheric Attenuation Prediction with New Models According to Local Weather Data for FSO Applications

Abstract

A dedicated Free Space Optical Link (FSOL) for the range of 0.5 km at an altitude of 15.25 m is established and explained. The power levels of the received signal with meteorological parameters are continuously measured using the opto-electronic assembly and developed weather station respectively and stored in a computer. The existing models selected for comparative analysis are briefed. Measured meteorological parameters and optical attenuation of size [2000 Â 4] are used for linear regression analysis as well as to design the mathematical models more suitable at the test field. In addition, the prediction accuracy of the proposed and selected models during different seasons in one-year period are investigated and validated in terms of RMSE. The average Root Mean Square Error (RMSE) of 0.041 dB/km for the optical attenuation is achieved in the longer range dynamic of meteorological parameters during different local seasons.

Quality Metrics and Reliability Analysis of Laser Communication System

“…During data transmission, the angle between the T x and R x line of sight and the transmitting beam axis must be kept within a fraction of the transmitting beamwidth which may be as smaller as a few micro-radians as discussed in Section-I. In laser communication, the fluctuations of the P r have to be related with the A att and C n 2 to characterise the turbulent channel effects on the propagated data carrying optical beam 8,10,[18][19][20][21][22][23] . The data carrying modulated optical beam cannot be used to measure the A att and the C n 2 since it bears data (information) and its average power get fluctuated at the receiver plane due to the modulation of the beam even under a favorable atmospheric condition 21,23 .…”

“…In laser communication, the fluctuations of the P r have to be related with the A att and C n 2 to characterise the turbulent channel effects on the propagated data carrying optical beam 8,10,[18][19][20][21][22][23] . The data carrying modulated optical beam cannot be used to measure the A att and the C n 2 since it bears data (information) and its average power get fluctuated at the receiver plane due to the modulation of the beam even under a favorable atmospheric condition 21,23 . One way of simultaneously measuring the A att and C n 2 is using a separate unmodulated optical setups/link, i.e., beacon beam, parallel to the data bearing optical path as a transmissometer for A att and scintillometer for C n 2 as detailed 6,18,21,23 .…”

“…The data carrying modulated optical beam cannot be used to measure the A att and the C n 2 since it bears data (information) and its average power get fluctuated at the receiver plane due to the modulation of the beam even under a favorable atmospheric condition 21,23 . One way of simultaneously measuring the A att and C n 2 is using a separate unmodulated optical setups/link, i.e., beacon beam, parallel to the data bearing optical path as a transmissometer for A att and scintillometer for C n 2 as detailed 6,18,21,23 . This approach will increase the overall cost of the system.…”

“…Furthermore, the atmospheric effect mitigation system is required to stabilize this beam also. Therefore, models yielding more accurate estimation of A att (dB/km) and C n 2 (m -2/3 ) according to the local weather data at our test field are formulated as described 21,23 , and given in Eqns. (2) …”

“…(2) in the Beer Lambert law as detailed in 6,8,23 and the maximum transmittance (T amax ) is obtained when the A att is minimum. , and C 22 = 1.65 e -6 .…”