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

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

Vehicular Visible Light Communications

Vehicular communications are foreseen to play a key role to increase road safety and realize autonomous driving. In addition to the radio frequency (RF)-based dedicated short range communication (DSRC) and long-term evolution (LTE) communication technologies, vehicular visible light communication (V2LC) is proposed as a complementary solution, utilizing readily deployed vehicle light emitting diode (LED) lights as transmitter with image sensors such as photodetector (PD) and camera as the receivers. V2LC fundamentals including transmitter and receiver characteristics with dimming capabilities are reviewed in this chapter. Depending on the field measurements using off-the-shelf automotive LED light, communication constraints are demonstrated. Moreover, considering the line-of-sight (LoS) characteristics, security aspects of V2LC is compared with the DSRC for a practical vehicle-to-vehicle (V2V) communication scenario. Finally, superiority of V2LC in terms of communication security with the proposed SecVLC method is demonstrated through simulation results

A Free Space Optic/Optical Wireless Communication: A Survey

The exponential demand for the next generation of services over free space optic and wireless optic communication is a necessity to approve new guidelines in this range. In this review article, we bring together an earlier study associated with these schemes to help us implement a multiple input/multiple output flexible platform for the next generation in an efficient manner. OWC/FSO is a complement clarification to radiofrequency technologies. Notably, they are providing various gains such as unrestricted authorizing, varied volume, essential safekeeping, and immunity to interference.

Vehicular Visible Light Positioning using Receiver Diversity with Machine Learning

This paper proposes a 2-D vehicular visible light positioning (VLP) system using existing streetlights and diversity receivers. Due to the linear arrangement of streetlights, traditional positioning techniques based on triangulation or similar algorithms fail. Thus, in this work, we propose a spatial and angular diversity receiver with machine learning (ML) techniques for VLP. It is shown that a multi-layer neural network (NN) with the proposed receiver scheme outperforms other ML algorithms and can offer high accuracy with root mean square (RMS) error of 0.22 m and 0.14 m during the day and night time, respectively. Furthermore, the NN shows robustness in VLP across different weather conditions and road scenarios. The results show that only dense fog deteriorates the performance of the system due to reduced visibility across the road

Performing the high bitrate visible light communications in the foggy weather to anticipate the interference on vehicle communications

We propose transmission media with visible light to communicate between vehicles. We evaluate the research under four scenarios using the modulation of On-Off Keying Non-Return to Zero (OOK-NRZ) and bitrate up to 1 Gbps. These scenarios are (i) ideal conditions, (ii) interference from other vehicle lights, (iii) foggy conditions, and (iv) interference from vehicles and fog conditions. Based on the extensive simulation, the results obtained are that interference and fog conditions can affect and reduce the value of the signal to interference and noise ratio (SNR) and increase the value of the error rate (BER). The results obtained are that interference and fog conditions can affect and reduce the value of the signal to interference and noise ratio (SNR) and increase the value of the error rate (BER). The SNR value in the first scenario is 23.6 dB and the second scenario is 11.1 dB, where this value is still sufficient. The SNR in scenario three is 16.1 dB, and the lowest in the fourth scenario is -7.78326 dB, indicating that the noise is extensive compared to signal power. In addition, we also obtain an optimal distance of communication between vehicles for each scenario sequentially 14.5 m, 13 m, 11.5 m, and 9 m

High speed train communications systems using free space optics

In this work, we propose a broad-band free space optical (FSO) wireless communications system for high-speed trains. The system consists of optical transceivers positioned outside the train and along the railway track. The train receivers are in the coverage area of base stations positioned along the railway track to ensure continuous link availability. In this paper, we present modelling of two cases for over-ground and underground train systems before embarking to practically implement the system in our research laboratory. Also discussed is the protocol for the data distribution along the track as well as the initial experimental demonstration of the proposed link