Performance of Free Space Optical Terrestrial Link under Dense Fog Conditions

Abstract

Free-space optical links use modulated beam of light to transmit high amount of data from transmitter to receiver to get line-of-sight communication link. Free-space optical is cost effective solution to provide higher data rate to end-users. Free-space optical links are also considered as a better alternative to RF links due to their advantages of low power consumption and higher data rate of the range Gbps, and are highly secure to electromagnetic interference. Despite of having all these advantages free-space optical links are highly affected by the severe weather conditions like fog, rain, snow, smoke and dust or aerosol particles suspended in air. Fog is one of a major challenge for free-space optical to achieve carrier class availability and causes high amount of attenuation. In this paper we presented the performance analysis of free-space optical links by estimating signal-to-noise ratio, bit error rate, under fog conditions during winter season in Lahore, Pakistan.

Investigation of optimum FSO communication link using different modulation techniques under fog conditions

“…It can be observed that none of these techniques give better results for a 1.8 km link distance [ 12 ]. It is obvious that under clear sky conditions, the system performance can be more impressive and reasonable but for an attenuation level of 25 dB/km link distance is limited [ 15 ]. It is obvious that under clear sky conditions, the system performance can be more impressive and reasonable but for an attenuation level of 25 dB/km link distance is limited.…”

“…These severe weather conditions reduce the visibility of the environmental layer in which optical signals travel toward the receiver side. The low visibility of the environmental channel offers high optical attenuation due to absorption and scattering phenomenon which degrades the efficiency of the communication link by reducing the link margin [ 15 ]. The effect of scintillation also has the degradation effects on the communication link performance.…”

“…Fog is perceived as one of the most crucial factor that substantially degrades the performance of the FSO communication [ 8 ]. Several critical fog events occurred in Lahore, Pakistan for the duration of up to 17 h on the 23rd of December 2014 and during this event, the average attenuation was 350.7 dB/km [ 15 ]. It is hard to find an end-user link with suitable bandwidth because the bottleneck issues of existing wireless communication with licensed or regulated bandwidth are a reason which is required to address.…”

“…The authors discuss the improvement of the capacity of communication using MIMO in attenuation. The performance evaluating parameters of the FSO link is SNR and Q-factor of the received signal can also be improved and BER also decreased by increasing transmitter power up to a limit in fog attenuation conditions [ 15 ]. Transmitter design factors are considered to be very important for an efficient FSO communication link.…”

Performance analysis of FSO communications in desert environments

“…Notably, there is a scarcity of literature and research that specifically investigates the consequences of duststorms on FSO communication. Because dust storms are unpredictable and there is little understanding about their impact on FSO connections, researchers have created dedicated experimental facilities to explore the effects of duststorms on FSO channels [11][12][13][14]. The authors in [15] and [16] have conducted practical experiments to examine the adverse consequences of dusty channels on FSO connections, aiming to enhance performance using various methodologies.…”