Experimental Investigation of the Effects of Fog on Optical Camera-based VLC for a Vehicular Environment

Abstract

The widespread increase in the use of light emitting diodes in vehicle's head and taillights and also the use of dashboard cameras provides great prospects for the optical camera based visible light communications (VLC) technology in intelligent transport systems. In this paper, we experimentally investigate the impact of fog on the optical camera based VLC technology for vehicle-to-vehicle (V2V) communications. A range of meteorological visibilities between 5-120 m is considered based on realistic inter-vehicle distances in practical vehicular environments and using a real car taillight as the transmitter. We show a reduction in the index of modulation of the signals from 1 to 0.75 and 0.5 to allow for tracking purposes of the light source when sending '0' symbols. The results show that, the link is error-free up to 20 m meteorological visibility for the three modulation index scenarios and degrades considerably below 10 m meteorological visibility.

Wireless Sensor Networks Using Sub-Pixel Optical Camera Communications: Advances in Experimental Channel Evaluation

“…The features of the chamber are listed in Table 3 . The level of fog was studied by means of the meteorological visibility (V) [ 51 ] measured by a laser source-power meter couple aligned across the chamber, parallel to the OCC link, and the turbulence level was estimated by the well-known refractive-index structure parameter, as derived in [ 42 ], using an array of 20 temperature sensors set up equidistantly across the chamber. The diagram of the setup is shown in Figure 6 .…”

Common-mode noise filtering with space-divided differential 2x2 VLC for V2V applications

“…There are also studies on the specific impact of some dedicated weather conditions (e.g. fog and rain) (Elamassie et al 2018;Eso et al 2019;Kim et al 2015) to the VLC-V2V channel. As VLC-V2V is an alternative to short-range radiofrequency (RF) communication, the VLC channel is compared to the RF-V2V channel in Cheng (2018).…”

“…In most cases, a Line-of-Sight (LOS) transmission is assumed. There are also studies on non-LOS cases, discussed in , with an amount of attenuation caused by weather and other environmental effects (Karbalayghareh et al 2020;Eso et al 2019;Singh et al 2019). The VLC-V2V channel is substantially affected by natural ambient light, sun irradiance Islim et al (2018) and artificial light sources: traffic lights, public lighting, other VLC interference from nearby vehicles or objects (Beshr et al 2015;Chung and Oh 2013).…”

“…Signal, noise and interference on the receiver side (RX) In VLC-V2V links the majority of optical receivers are either high-speed cameras (Eso et al 2019;Halawi 2019;Takai 2014) or photodiode based amplified detectors (Chung and Oh 2013;Ahmed and Bermak 2019). In several experimental VLC-V2V links, only one receiver is attached to the back or the front section of the vehicle.…”

Experimentally Derived Feasibility of Optical Camera Communications under Turbulence and Fog Conditions

“…Works addressing channel characterization in outdoor OCC links [20] are still scarce compared to the amount of research on PD-based VLC. In the previous work [26], we evaluated the feasibility of a global shutter-based OCC link under fog conditions by the success rate of bits of vehicular link experimentally tested with a red brake light and a digital reflex camera. For a modulation index of 75%, the system showed high reliability under dense fog conditions up to a meteorological visibility of 20 m.…”