Comparison of Radio Frequency and Visible Light Propagation Channels for Vehicular Communications

Recent research has shown that both radio and visible light waves can be used to enable communications in highly dynamic vehicular environments. However, the roles of these two technologies and how they interact with each other in future vehicular communication systems remain unclear. Understanding the propagation characteristics is an essential step in investigating the benefits and shortcomings of each technology. To this end, we discuss salient properties of radio and visible light propagation channels, including radiation pattern, path loss modeling, noise and interference, and channel time variation. Comparison of these properties provides an important insight that the two communication channels can complement each other’s capabilities in terms of coverage and reliability, thus better satisfying the diverse requirements of future cooperative intelligent transportation systems

Flight: A Flexible Light Communications network architecture for indoor environments

Recent experimental works have demonstrated the feasibility of the visible light based vehicular communications (VVLC) in intelligent transportation systems (ITS). However, in many respects, this technology is in its infancy and requires further research efforts in several areas. This work presents a flexible network architecture named flexible light (Flight), which is designed for VLC to tackle existing mobility challenges in the network environment. Flight proposes a low-latency handover system that decreases the handover delays to a few tens and hundreds of milliseconds. By means of experiments, we emulate and evaluate indoor mobile network scenarios using only VLC technology

A Multi-Hop Relay Based Routing Algorithm for Vehicular Visible Light Communication Networks

The use of visible light communications (VLC) in intelligent transportation systems is becoming highly popular. In this paper, we present a predictionbased channel gain model and propose a multi-hop relaybased routing algorithm for vehicular VLC communication networks. Using the surrogate modeling lab platform SUMO and Matlab we show that, a stationary velocity of vehicles is better suited to form a good prediction, while the proposed routing algorithm offers improved signal-to-noise ratio

A New Vehicle Localization Scheme Based on Combined Optical Camera Communication and Photogrammetry

The demand for autonomous vehicles is increasing gradually owing to their enormous potential benefits. However, several challenges, such as vehicle localization, are involved in the development of autonomous vehicles. A simple and secure algorithm for vehicle positioning is proposed herein without massively modifying the existing transportation infrastructure. For vehicle localization, vehicles on the road are classified into two categories: host vehicles (HVs) are the ones used to estimate other vehicles' positions and forwarding vehicles (FVs) are the ones that move in front of the HVs. The FV transmits modulated data from the tail (or back) light, and the camera of the HV receives that signal using optical camera communication (OCC). In addition, the streetlight (SL) data are considered to ensure the position accuracy of the HV. Determining the HV position minimizes the relative position variation between the HV and FV. Using photogrammetry, the distance between FV or SL and the camera of the HV is calculated by measuring the occupied image area on the image sensor. Comparing the change in distance between HV and SLs with the change in distance between HV and FV, the positions of FVs are determined. The performance of the proposed technique is analyzed, and the results indicate a significant improvement in performance. The experimental distance measurement validated the feasibility of the proposed scheme