The Effects of Power Control on Free-Space Optical Communications during Snowfall and Rainfall

Abstract

Free-space optical (FSO) communication requires a line-of-sight connection between a transmitter and a receiver in which the information signal is modulated by an optical carrier that propagates in free space. The FSO channel is greatly affected by weather conditions such as fog, rain, and snow. In the literature, several adaptive techniques, such as power control (PC), have been suggested to mitigate channel link degradations. In this paper, we investigate the effects of snow and rain attenuation on the bit error rate (BER) of the FSO system using two types of modulations, the on-off keying (OOK) modulation and the pulse-position modulation (16-PPM). The effect of PC on the performance of FSO communications is also examined in this study. We evaluated the system's performance with two types of snow, wet snow and dry snow, as well as with different rain regions. Results show that PC improves the BER of the FSO system; a high rate of improvement is found for wet snow and rain. PC has almost no effect with dry snow because of the high attenuation and the limitations on transmitted power. The BER for 16-PPM is better than that for OOK modulation.

6G Network Architecture Using FSO-PDM/PV-OCDMA System with Weather Performance Analysis

“…The proposed FSO-PDM/PV-OCDMA system is evaluated and simulated using Matlab and Optisystem software version 18 with the parameters mentioned in Table 2 [27][28][29][30][31]. Optisystem is a commercial tool that offers designing, simulation, and optimization of optical components, links, systems, and networks.…”

“…Moreover, the system with eight channels carry information is simulated under different snowfall rates to show the effect of the propagation ranges on the information signal. From Figures 12 and 13, the maximum FSO link for eight simulated channels is 1.15 km under WS, which causes attenuation (13.73 dB/km) less than that caused under DS (attenuation is 96.8 dB/km [31]). So, the FSO range for eight channels is decreased to 0.28 km under DS.…”

“…nal. From Figures 12 and 13, the maximum FSO link for eight simulated channels is 1.15 km under WS, which causes attenuation (13.73 dB/km) less than that caused under DS (attenuation is 96.8 dB/km [31]). So, the FSO range for eight channels is decreased to 0.28 km under DS.…”