A Comprehensive Investigation on Multi-User Interference Effects in Vehicular Visible Light Communications

Abstract

Vehicular visible light communications (VLC) are considered a suitable technology for vehicular platooning applications. Nevertheless, this domain imposes strict performance requirements. Although numerous works have shown that VLC technology is compatible with platooning applications, existing studies are mainly focused on the physical layer performances, mostly ignoring the disruptive effects generated by neighboring vehicular VLC links. Nevertheless, the 5.9 GHz Dedicated Short Range Communications (DSRC) experience has shown that mutual interference can significantly affect the packed delivery ratio, pointing out that these effects should be analyzed for vehicular VLC networks as well. In this context, this article provides a comprehensive investigation focused on the effects of mutual interference generated by neighboring vehicle-to-vehicle (V2V) VLC links. Therefore, this work provides an intensive analytical investigation based on simulation and also on experimental results that demonstrate that although ignored, the influence of mutual interference is highly disruptive in vehicular VLC applications. Hence, it has been shown that without preventive measures, the Packet Delivery Ratio (PDR) can decrease below the imposed 90% limit for almost the entire service area. The results have also shown that although less aggressive, multi-user interference affects V2V links even in short-distance conditions. Therefore, this article has the merit of emphasizing a new challenge for vehicular VLC links and points out the importance of multiple-access techniques integration.

Addressing Multi-User Interference in Vehicular Visible Light Communications: A Brief Survey and an Evaluation of Optical CDMA MAC Utilization in a Multi-Lane Scenario

“…An intensive analytical and experimental evaluation demonstrating the highly disruptive effects of MUI on inter-vehicle VLC can be found in [35]. Here [35], computer simulations and experimental investigations showed that depending on the MUI intensity, the PDR can be significantly affected, reaching in certain conditions values below 40%. The authors of [36,37] perform analyses of the vehicular VLC channel model based on the impact of real vehicle lighting system radiation patters.…”

“…On the other hand, a careful analysis of vehicular VLC systems parameters indicated that coverage area is limited by narrow receiver FOV, whereas the FOV increase leads to a higher number of neighboring vehicles within the Line of Sight (LoS), generating in turn a higher collision probability and lower data delivery percentage [34]. An intensive analytical and experimental evaluation demonstrating the highly disruptive effects of MUI on inter-vehicle VLC can be found in [35]. Here [35], computer simulations and experimental investigations showed that depending on the MUI intensity, the PDR can be significantly affected, reaching in certain conditions values below 40%.…”

The Concept regarding Vehicular Communications Based on Visible Light Communication and the IoT

“…Therefore, this approach is extremely important for the scientific environment and, as a result of the experience accumulated in this field, presents a viable alternative through which this technology will soon be able to branch out into more fields. Even if technological advances favor communication based on the 802.11 p/a standard, 4G, 5G, and even 6G, the complementarity and usefulness of VLC are undeniable [58,59].…”

Experimental Demonstration of a Visible Light Communications System Based on Binary Frequency-Shift Keying Modulation: A New Step toward Improved Noise Resilience

“…Nevertheless, in many cases, the VLC receiver is exposed to other sources of light, not just to the VLC transmitter. In vehicular applications, the VLC receiver can be exposed to multi-user interferences (MUI) [25,26], but it can also be exposed to a multitude of other light sources (artificial and natural) [9]. Among all optical noise sources, sunlight is considered to be the most disruptive, as it can reach intensities that can go above 65,000 µW/cm 2 .…”