Optical Wireless Communications Lab - VLC - USV

How does LiFi work? How will LiFi connect the world through light, offering faster, more secure and safe wireless communications with unprecedented data and bandwidth?

How Does LiFi Work? How does LiFi work? How will LiFi connect the world through light, offering faster, more secure and safe wireless communications with unprecedented data and ...

Li-Fi holds the potential to unlock a new era in digital communication, resulting in much faster and more reliable wireless connectivity. Unlike Wi-Fi which uses radio waves to transmit data, Li-Fi uses light waves which results in unprecedented transfer speeds over short distances. 802.11bb is an IEEE Standard that has been developed for Li-Fi as its range, bandwidth and future marketability continue to expand. Hear more insights from IEEE Standards Association working group member Volker Jungnicke on IEEE Spectrum: https://bit.ly/3S3zQxx

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


Abstract
Visible Light Communications (VLC) are developing as an omnipresent solution for inter-vehicle communications. Based on intensive research efforts, the performance of vehicular VLC systems has significantly improved in terms of noise resilience, communication range, and latencies. Nevertheless, in order to be ready for deployment in real applications, solutions for Medium Access Control (MAC) are also required. In this context, this article provides an intensive evaluation of several optical CDMA MAC solutions and of their efficiency in mitigating the effect of Multiple User Interference (MUI). Intensive simulation results showed that an adequately designed MAC layer can significantly reduce the effects of MUI, ensuring an adequate Packet Delivery Ratio (PDR). The simulation results showed that based on the use of optical CDMA codes, the PDR can be improved from values as low as 20% up to values between 93.2% and 100%. Consequently, the results provided in this article show the high potential of optical CDMA MAC solutions in vehicular VLC applications, reconfirm the high potential of the VLC technology in inter-vehicle communications, and emphasize the need to further develop MAC solutions designed for such applications.
Keywords: multi-user interference; multi-user interference mitigation; OCDMA; optical interference; vehicle-to-vehicle communications; V2V; VLC; VLC MAC solutions; visible light communications

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 Visible Light Communications (VLC) are developing as an omnipresent solution for inter-vehicle communications. Based on intensive research efforts, the performance of vehicular VLC systems has significantly improved in terms of noise resilience, communication range, and latencies. Nevertheless, in o...

Increasing Vehicular Visible Light Communications Range Based on LED Current Overdriving and Variable Pulse Position Modulation: Concept and Experimental Validation

Due to its unique advantages, the integration of Visible Light Communications (VLC) in vehicle safety applications has become a major research topic. Nevertheless, as this is an emergent technology, several challenges must be addressed. One of the most important of these challenges is oriented toward increasing vehicular VLC systems’ communication range. In this context, this article proposes a novel approach that provides a significant communication distance enhancement. Different from most existing works on this topic, which are based on refining the VLC receiver, this new article is focused on improving the VLC system based on the benefits that can be achieved through the VLC transmitter. The concept is based on Light-Emitting Diode (LED) current overdriving and a modified Variable Pulse Position Modulation (VPPM). Therefore, LED current overdriving provides the VLC receiver higher instantaneous received optical power and improved Signal-to-Noise Ratio (SNR), whereas the use of the VPPM ensures that the VLC transmitter respects eye regulation norms and offers LED protection against overheating. The concept has been experimentally tested in laboratory conditions. The experimental results confirmed the viability of the concept, showing an increase of the communication range by up to 370%, while maintaining the same overall optical irradiance at the VLC transmitter level. Therefore, this new approach has the potential to enable vehicular VLC ranges that cover the requirements of communication-based vehicle safety applications. To the best of our knowledge, this concept has not been previously exploited in vehicular VLC applications.

Keywords: inter-vehicle communications; LED current overdriving; optical communications; optical wireless communications; traffic safety; vehicle to vehicle communications; visible light communication; VLC range; V2V

Increasing Vehicular Visible Light Communications Range Based on LED Current Overdriving and Variable Pulse Position Modulation: Concept and Experimental Validation Due to its unique advantages, the integration of Visible Light Communications (VLC) in vehicle safety applications has become a major research topic. Nevertheless, as this is an emergent technology, several challenges must be addressed. One of the most important of these challenges is oriented towar...

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

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.

Keywords: inter-vehicle communications; multi-user interference; optical interference; V2V; vehicle safety; VLC; visible light communication

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

Experimental Demonstration of a Visible Light Communications Crosswalk Assistance System

In the context in which pedestrians are the most exposed road user category in urban areas, this paper presents the results of an experimental demonstration of a new system designed to assist pedestrians in safely using a crosswalk. The proposed architecture consists of a pedestrian detection and localization unit that detects pedestrians in the crosswalk area, a visible light communications component that transmits this information toward the approaching vehicles using the visible light communications technology and a graphical user interface that enables the driver to receive relevant traffic safety information. The experimental investigation has shown that based on a multi-sensor data fusion approach, pedestrians are detected with an overall 100% detection rate, whereas the low power crosswalk sign VLC emitter can provide a communication range of up to 27 ― 40 meters, with a data rate of 100 kb/s and a BER in the 10– 7 ― 10– 4 range. Therefore, the experimental results indicate that the proposed VLC system has high performance in traffic situations that could pose serious issues to other concepts.

Experimental Demonstration of a Visible Light Communications Crosswalk Assistance System In the context in which pedestrians are the most exposed road user category in urban areas, this paper presents the results of an experimental demonstration of a new system designed to assist pedestrians in safely using a crosswalk. The proposed architecture consists of a pedestrian detection and lo...

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