Experimental measurements of a joint 5G-VLC communication for future vehicular networks

One of the main revolutionary features of 5G networks is the ultra-low latency that will enable new services such as those for the future smart vehicles. The 5G technology will be able to support extreme-low latency. Thanks to new technologies and the wide flexible architecture that integrates new spectra and access technologies. In particular, Visible Light Communication (VLC) is envisaged as a very promising technology for vehicular communications, since the information can flow by using the lights (as traffic-lights and car lights). This paper describes one of the first experiments on the joint use of 5G and VLC networks to provide real-time information to cars. The applications span from road safety to emergency alarm

LEDs assisted navigation in connected cars

Dissertação de natureza científica para obtenção do grau de Mestre em Engenharia Eletrónica e TelecomunicaçõesAlternative wireless technologies are needed due to the increasing traffic demand and the shortage of RF band. VLC uses the visible light spectrum to encode and transmit information and is a complement to RF, providing additional bandwidth. Traffic lights are the main infrastructures to control access to roads and will soon be replaced by more efficient structures to improve traffic management. The goal of this dissertation is the characterization and test of communication links based on VLC technology for road management applications. Transmitters of the VLC link are tetrachromatic white LEDs used for illumination and data transmission. The characterization of the optical transmitter system is done through MATLAB simulations, using the Lambertian model. Receivers based on a-SiC:H/a-Si:H photodiodes with selective spectral sensitivity are used to. The studied scenario is a crossroad formed by five cells, with a LED at each corner providing a certain coverage and forming nine footprints. The OOK modulation was used, and the transmitted message follows a 64-bit frame structure. The coverage map and footprint map were obtained as outputs. A calibration curve was used in the encoding and decoding process. Two trajectories were tested: vehicle moving from West to East and from West to North. The encoded process was successful, proving that the simulation tool developed produces valid results. The decoding process was successful with the simulated results but not so much with the signals measured in the laboratory. The red LED/channel presented the least error followed by the green, since these are more distinguishable. The blue and violet LED/channel are less distinguishable and presented the most errors. Adjusting the calibration curve or implementing error detection mechanism are proposed as solutions. A GUI was developed to enable easy interaction between the user and the simulation tool.Devido ao aumento da procura de tráfego e diminuição da banda RF disponível são necessárias tecnologias sem fios alternativas. O VLC utiliza o espetro visível para codificar e transmitir informação, sendo um complemento ao RF fornecendo largura de banda adicional. Os semáforos são as principais infraestruturas de controlo de acesso às estradas e serão eventualmente substituídas por estruturas mais eficiente para melhorar a gestão do trânsito. O objetivo desta dissertação é a caracterização e teste da comunicação utilizando a tecnologia VLC em aplicações de gestão rodoviária. Os transmissores usados para iluminação e comunicação são LEDs tetra-cromáticos. A caracterização do transmissor ótico foi realizada em MATLAB usando o modelo Lambertiano. O recetor utilizado é um foto-detetor baseado em estruturas pin de a-SiC:H e a-Si:H que apresentam sensibilidade espectral seletiva. O cenário estudado é um cruzamento formado por cinco células, com um LED em cada canto, proporcionando uma cobertura específica e formando em conjunto nove footprints. Foi usada a modulação OOK e a mensagem enviada utiliza uma estrutura de 64 bits. Como resultados, foram obtidos mapas de cobertura e de footprints. A curva de calibração foi usada para o processo de codificação e descodificação. Foram testadas duas trajetórias: veículos provenientes de Oeste para Este e de Oeste para Norte. O processo de codificação foi bem-sucedido, mostrando que a ferramenta de simulação desenvolvida produz resultados válidos. O processo de descodificação foi bem-sucedido para os resultados simulados, mas apresenta erros para as medidas laboratoriais. O LED/canal vermelho apresentou menos erros, seguido do verde pois estes são mais distinguíveis. O azul e o violeta são menos distinguíveis, apresentando mais erros. As soluções propostas são ajustar a curva de calibração ou implementar de mecanismos de deteção de erros. Foi desenvolvida uma interface gráfica para facilitar a interação entre utilizador e ferramenta de simulação.info:eu-repo/semantics/publishedVersio

Etude et réalisation d'un système de communications par lumière visible (VLC/LiFi). Application au domaine automobile.

The scientific problematic of this PhD is centered on the usage of Visible LightCommunications (VLC) in automotive applications. By enabling wireless communication amongvehicles and also with the traffic infrastructure, the safety and efficiency of the transportation canbe substantially increased. Considering the numerous advantages of the VLC technologyencouraged the study of its appropriateness for the envisioned automotive applications, as analternative and/or a complement for the traditional radio frequency based communications.In order to conduct this research, a low-cost VLC system for automotive application wasdeveloped. The proposed system aims to ensure a highly robust communication between a LEDbasedVLC emitter and an on-vehicle VLC receiver. For the study of vehicle to vehicle (V2V)communication, the emitter was developed based on a vehicle backlight whereas for the study ofinfrastructure to vehicle (I2V) communication, the emitter was developed based on a traffic light.Considering the VLC receiver, a central problem in this area is the design of a suitable sensorable to enhance the conditioning of the signal and to avoid disturbances due to the environmentalconditions, issues that are addressed in the thesis. The performances of a cooperative drivingsystem integrating the two components were evaluated as well.The experimental validation of the VLC system was performed in various conditions andscenarios. The results confirmed the performances of the proposed system and demonstrated thatVLC can be a viable technology for the considered applications. Furthermore, the results areencouraging towards the continuations of the work in this domain.La problématique scientifique de cette thèse est centrée sur le développement decommunications par lumière visible (Visible Light Communications - VLC) dans lesapplications automobiles. En permettant la communication sans fil entre les véhicules, ou entreles véhicules et l’infrastructure routière, la sécurité et l'efficacité du transport peuvent êtreconsidérablement améliorées. Compte tenu des nombreux avantages de la technologie VLC,cette solution se présente comme une excellente alternative ou un complément pour lescommunications actuelles plutôt basées sur les technologies radio-fréquences traditionnelles.Pour réaliser ces travaux de recherche, un système VLC à faible coût pour applicationautomobile a été développé. Le système proposé vise à assurer une communication très robusteentre un émetteur VLC à base de LED et un récepteur VLC monté sur un véhicule. Pour l'étudedes communications véhicule à véhicule (V2V), l'émetteur a été développé sur la base d’un pharearrière rouge de voiture, tandis que pour l'étude des communications de l'infrastructure auvéhicule (I2V), l'émetteur a été développé sur la base d'un feu de circulation. Considérant lerécepteur VLC, le problème principal réside autour d’un capteur approprié, en mesured'améliorer le conditionnement du signal et de limiter les perturbations dues des conditionsenvironnementales. Ces différents points sont abordés dans la thèse, d’un point de vue simulationmais également réalisation du prototype.La validation expérimentale du système VLC a été réalisée dans différentes conditions etscénarii. Les résultats démontrent que la VLC peut être une technologie viable pour lesapplications envisagées

A Survey of Positioning Systems Using Visible LED Lights

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.As Global Positioning System (GPS) cannot provide satisfying performance in indoor environments, indoor positioning technology, which utilizes indoor wireless signals instead of GPS signals, has grown rapidly in recent years. Meanwhile, visible light communication (VLC) using light devices such as light emitting diodes (LEDs) has been deemed to be a promising candidate in the heterogeneous wireless networks that may collaborate with radio frequencies (RF) wireless networks. In particular, light-fidelity has a great potential for deployment in future indoor environments because of its high throughput and security advantages. This paper provides a comprehensive study of a novel positioning technology based on visible white LED lights, which has attracted much attention from both academia and industry. The essential characteristics and principles of this system are deeply discussed, and relevant positioning algorithms and designs are classified and elaborated. This paper undertakes a thorough investigation into current LED-based indoor positioning systems and compares their performance through many aspects, such as test environment, accuracy, and cost. It presents indoor hybrid positioning systems among VLC and other systems (e.g., inertial sensors and RF systems). We also review and classify outdoor VLC positioning applications for the first time. Finally, this paper surveys major advances as well as open issues, challenges, and future research directions in VLC positioning systems.Peer reviewe