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Communication-based vehicle safety applications have the potential to take traffic safety to the next level. This type of application envisions that vehicles on the road exchange traffic safety relevant data in order to cooperate toward traffic accident prevention, improved traffic efficiency and better driving experience. In this context, this paper provides an analysis of the vehicle-to-vehicle coverage in a two-lane driving scenario for the visible light communication (VLC) technology. Thus, it provides the experimental evaluation of this coverage range using a VLC prototype based on standard LED vehicle rear lights. The experimental results demonstrate a communication range of at least 50 meters, with an initial 2-8 meters region not covered by the receiver’s FOV, when the vehicles are on adjacent lanes. The analysis of bit error rate results shows that even with an adequate signal processing, the number of errors can increase by about two order of magnitude when the vehicles are located on neighboring lanes.

The use of Visible Light Communications (VLC) in vehicular applications has become a major research area due to its simplicity, high performance to cost ratio, and great deployment potential. In this context, this article provides one of the very few analyses and experimental evaluations concerning the integration of a light dimming function in vehicular VLC systems. For this purpose, a vehicle-to-vehicle VLC prototype has been implemented and used to evaluate the systems’ communication performances in light dimming conditions, while decreasing the duty cycle from 40% to 1%, and increasing the communication range from 1 to 40–50 m. The experimental results showed that in normal lighting conditions, the VLC technology can easily support low duty cycle light dimming for ranges up to 40 m, while maintaining a 10−6 BER. Nevertheless, in strong optical noise conditions, when the system reaches its SNR limit, the communication range can decrease by half, whereas the BER can increase by 2–4 orders of magnitude. This article provides consistent evidence concerning the high potential of the VLC technology to support inter-vehicle communication links, even in light dimming conditions.

The use of visible light communications technology in communication-based vehicle applications is gaining more and more interest as the research community is constantly overcoming challenge after challenge. In this context, this article addresses the issues associated with the use of Visible Light Communications (VLC) technology in Vehicle-to-Vehicle (V2V) communications, while focusing on two crucial issues. On the one hand, it aims to investigate the achievable communication distance in V2V applications while addressing the least favorable case, namely the one when a standard vehicle rear lighting system is used as a VLC emitter. On the other hand, this article investigates another highly unfavorable use case scenario, i.e., the case when two vehicles are located on adjacent lanes, rather than on the same lane. In order to evaluate the compatibility of the VLC technology with the usage in inter-vehicle communication, a VLC prototype is intensively evaluated in outdoor conditions. The experimental results show a record V2V VLC distance of 75 m, while providing a Bit Error Ratio (BER) of 10−7–10−6. The results also show that the VLC technology is able to provide V2V connectivity even in a situation where the vehicles are located on adjacent lanes, without a major impact on the link performances. Nevertheless, this situation generates an initial no-coverage zone, which is determined by the VLC receiver reception angle, whereas in some cases, vehicle misalignment can generate a BER increase that can go up to two orders of magnitude.

Visible light communications are considered as a promising solution for inter-vehicle communications, which in turn can significantly enhance the traffic safety and efficiency. However, the vehicular visible light communications (VLC) channel is highly dynamic, very unpredictable, and subject to many noise sources. Enhancing VLC systems with self-aware capabilities would maximize the communication performances and efficiency, whatever the environmental conditions. Within this context, this letter proposes a novel signal to noise ratio (SNR)-adaptive visible light communication receiver architecture aimed for automotive applications. The novelty of this letter comes from an open loop signal processing technique in which the signal treatment complexity is established based on a real-time SNR analysis. So, the receiver evaluates the SNR, and based on this assessment, it reconfigures its structural design in order to ensure a proper signal treatment, while providing an optimal tradeoff between communication performances and computational resources usage. This approach based on software reconfiguration has the potential to provide the system with enhanced flexibility and enables its usage in resource sharing application. As far as we know, this approach has not been considered in vehicular VLC systems. The performances of the proposed architecture are demonstrated by simulations, which confirm the SNR-adaptive capacity and the optimized performances.

Current research studies envision that the safety and the efficiency of road transportation can be significantly improved with the help of wireless communication technologies that enable inter-vehicle and traffic infrastructure to vehicle data exchange. Nevertheless, some studies also demonstrate that existing wireless technologies can have reliability issues that postpone their market deployment in automotive applications. In this context, this paper provides an analysis concerning the effect of snowfall on the performances of outdoor visible light communications (VLC). Thus, this work provides the results for the experimental evaluation of a 50 meters VLC traffic light to VLC receiver link in snowfall conditions. The experimental results show that moderate snow has a limited effect on VLC performances, whereas intensive snowfall and blizzard episodes significantly affect the Bit Error Ratio. So, the experimental results demonstrate that a physical BER as low as 10-7 can be achieved, whereas snowfall and blizzard can increase the error ratio up to 10-3 values.

As the interest toward communication-based vehicle safety applications is increasing, the development of secure wireless communication techniques has become an important research area. In this context, the article addresses issues that are related to the use of the visible light communication (VLC) technology in vehicular applications. Thus, it provides an extensive presentation concerning the main challenges and issues that are associated to vehicular VLC applications and of some of the existing VLC solutions. Moreover, the article presents the aspects related to the design and intensive experimental evaluation of a new automotive VLC system. The experimental evaluation performed in indoor and outdoor conditions shows that the proposed system can achieve communication distances up to 50 m and bit error ratio (BER) lower than 10&minus, 6, while being exposed to optical and weather perturbations. This article provides important evidence concerning the snowfall effect on middle to long range outdoor VLC, as the proposed VLC system was also evaluated in snowfall conditions. Accordingly, the experimental evaluation showed that snowfall and heavy gust could increase bit error rate by up to 10,000 times. Even so, this article provides encouraging evidence that VLC systems will soon be able to reliably support V2X communications.

Considering the wide deployment of LED lighting sources in the transportation domain, automotive Visible Light Communications arise as a highly promising research area. Nevertheless, due to the high intensity of parasitic light sources associated to rather low power data signals numerous challenges emerge. In this context, this paper is focused on the analysis of linear transimpedance circuit performances in automotive applications. Thus, it presents an analysis regarding the influence of strong sunlight on the photosensitive element. The analysis involves the simulation of a microcontroller-assisted variable gain transimpedance circuit that enables the VLC system to prevent saturation by reducing its sensitivity. By considering the emitted irradiance of lighting systems existing in transportation infrastructure, the maximum communication distance is determined. The results show that a variable gain transimpedance circuit can enable communication distances between 9 and more than 150 meters depending on the sunlight power and on the VLC receiver field of view.

To address the most common issues found in automotive Visible Light Communication applications, a new photodiode amplifier based on an instrumentation amplifier is proposed. In order to improve the results, buffer stages have been replaced with transimpedance amplifiers providing the circuit with offset cancellation loops that enable the sensing of the DC output offset and with T-networks in the feedback path, that reduce the effect of parasitic capacitances. Thus, the resulted output signal will be ready for further processing in the analog-digital conversion (ADC) stage providing improved results in terms of parasitic light resilience and SNR.

As communication-based safety applications are developed for the next generation of vehicle active safety systems, this article focuses on the benefits of using adaptive hysteresis circuits toward the development of environmental-adaptive VLC sensors with significantly enhanced performances. Thus, analytical and numerical approaches to analyze hysteresis systems with noisy input are discussed and the benefits of adaptive hysteresis are presented. Furthermore, a linear relation between optimal hysteresis thresholds and noise strengths is determined. The experimental validation of the theoretical results is performed by using a Schmitt Trigger with threshold values adjusted by digital potentiometers controlled by an embedded microcontroller. Significant BER improvement is obtained by the hysteresis threshold adjustment.

This article proposes a cost efficient and easy to implement frequency stabilization method orientated toward communication systems operating in an extensive temperature range, as the automotive or the aerospace applications. The proposed solution uses off-the-shelf components and it is optimized for very low power consumption. The novelty of this article is represented by the introduction of the barium strontium titanate capacitor for quartz crystal oscillator active frequency stabilization. After the design was completed, the performances were evaluated and compared to the ones of the uncompensated oscillator. Experimental results confirmed the suitability of the proposed design, achieving 35 times better frequency stability within variable temperature conditions, whereas the power consumption is maintained below 6mW.

Due to numerous advantages, Visible Light Communications are considered to have high potential in various areas. Thus, both new indoor and outdoor applications are being constantly identified. In this paper, we present a demonstration in which the VLC technology is used to transmit the University of Suceava campus radio station through the lighting system. This pilot project is currently implemented in the Optical Communications laboratory, with possible development within other laboratories or in the campus area. Thus, using a rather simple optical receiver based on a phototransistor, one can listen to the campus radio station received through the optical carrier. The purpose of this project is to demonstrate a simple application of VLC and to popularize this technology as an alternative and/or complement to the RF solution.

Wireless communications technologies have the potential to significantly improve the safety and the efficiency of the transportation system. Nevertheless, supporting the requirements imposed by the usage in vehicle safety applications is rather challenging. In such a context, this paper provides an overview of some of the most promising technologies that could be used in communication-based vehicle safety applications. The paper provides an overview of the DSRC technology as a favorite technology for such applications and of the VLC technology as a very promising emergent alternative. Based on this analysis, a hybrid architecture using DSRC and VLC is proposed. This architecture envisions that neighboring vehicles are interconnected based on VLC, whereas non-line of sight vehicles are connected through the DSRC network. Thus, an application for the connection of these network solutions is proposed and evaluated.

In the context of an increasing interest toward reducing the number of traffic accidents and of associated victims, communication-based vehicle safety applications have emerged as one of the best solutions to enhance road safety. In this area, visible light communications (VLC) have a great potential for applications due to their relatively simple design for basic functioning, efficiency, and large geographical distribution. This paper addresses the issues related to the VLC usage in vehicular communication applications, being the first extensive survey dedicated to this topic. Although VLC has been the focus of an intensive research during the last few years, the technology is still in its infancy and requires continuous efforts to overcome the current challenges, especially in outdoor applications, such as the automotive communications. This paper is aimed at providing an overview of several research directions that could transform VLC into a reliable component of the transportation infrastructure. The main challenges are identified and the status of the accomplishments in each direction is presented, helping one to understand what has been done, where the technology stands and what is still missing. The challenges for VLC usage in vehicle applications addressed by this survey are: 1) increasing the robustness to noise; 2) increasing the communication range; 3) enhancing mobility; 4) performing distance measurements and visible light positioning; 5) increasing data rate; 6) developing parallel VLC; and 7) developing heterogeneous dedicated short range communications and VLC networks. Addressing and solving these challenges lead to the perspective of fully demonstrating the high potential of VLC, and therefore, to enable the VLC usage in road safety applications. This paper also proposes several future research directions for the automotive VLC applications and offers a brief review on the associated standardization activities.

International audience; This article presents a novel visible light communications receiver architecture, designed for automotive applications. A central problematic in this area is the design of a suitable receiver able to face the problems caused by the dynamic situations, by the long distances and also by the environmental conditions. In such circumstances, a solution would be to adapt the communication's data rate to channel conditions, meaning that the communication would take place using different data rates depending on the signal to noise ratio (SNR) and the message priority. Considering the digital filtering better performances, the proposed architecture considers the usage of digital signal processing (DSP) as an alternative to the analog signal treatment. The visible light communication receiver proposed in this article addresses the upper mentioned issues and enables a robust communication even at low SNR.

Since more and more vehicles are using the transportation infrastructure, the safety and the efficiency of roads are of absolute importance. A solution to enhance the security of road transportation is by enabling wireless communications between vehicles and also with the traffic infrastructures (e.g., traffic lights, street lighting, or traffic signs). In this area, visible light communications (VLC) is considered of great perspective. A fundamental problematic in vehicular VLC is the design of a proper sensor capable to support long distance communications in dynamic traffic situations and in unfriendly atmospheric conditions. Therefore, this paper is focused on the design of the VLC sensors intended for vehicular communication applications, offering a review of the solutions found to mitigate the effect of the problematic conditions. Furthermore, this paper summarizes these solutions and proposes an environmental adaptive VLC receiver that would be capable to optimally adjust its settings in order to maximize the communication efficiency, but without affecting the communication robustness to noise.

This paper presents the development of an enhanced power supply designed for an intelligent traffic light used as a visible light communications emitter. In the context of an increasing preoccupation for alternative energy sources, the system is being supplied with solar energy which is converted in electric energy by a photovoltaic panel. In order to improve the efficiency of the panel, the system is enhanced with a patented solar tracking system and a microcontroller which is continuously monitoring the provided energy and is deciding its optimal use. The extra energy supplied by the solar panel can be stored in a supercapacitors block and used during unfavorable weather conditions or during the night time.

The study of meteors by radio using a bistatic RADAR configuration in the Low-VHF portion of the spectrum requires the use of receiving antennas that are not always easy to install while fulfilling the imposed requirements. In order to facilitate the implementation of radio meteor detection stations that operate in this frequency range, the parameters of vertical antennas with unusual characteristics were analyzed. These antennas are characterized as having uncommon features in term of geometry and radiation patterns, whereas they should be simple to build, feed and install. Based on this analysis, a directive vertical antenna array which exhibits by design the features that make it suitable for radio meteor detection is proposed and preliminary results are provided.

Communication-based vehicle safety technology represents one of the most promising solutions to enhance the safety and the efficiency of the transportation system. For this purpose, visible light communications (VLC) have great potential of development due to low-cost, widespread distribution, and unregulated radiation spectrum. Nevertheless, existing VLC systems are not able to fully comply with the requirements imposed by vehicle safety applications. One of the main aspects that need further enhancement is the communication distance. Within this context, this paper presents the preliminary experimental results of a novel VLC system achieving a 130 m traffic light to vehicle communication distance. The key elements for obtaining this result are the use of a phototransistor based VLC sensor for better sensitivity, a logarithmic transimpedance amplifier circuit to reduce the strong influence of parasitic light and the possibility of photoelement saturation, a Schmitt trigger with adaptive thresholds to enhance noise mitigation under variable signal-to-noise ratios, and advanced techniques for signal processing. To the best of our knowledge, this is the longest communication distance reported for automotive VLC link.

In the context of an impressive development of software defined networks and of internet technologies, this paper presents the aspects related to the implementation of an online wideband multimode radio receiver. The receiver was developed considering its main application in LEO satellite data reception, for frequencies up to 1.7 GHz. In additional to the hardware implementation description, the paper also provides an example of satellite data reception. An additional but very important utilization of the online receiver is represented by the educational component. Thus, as the receiver is available online, it can be used by students in order to get familiar to the satellite/radio communication notions.

In the context of an increasing preoccupation to reduce the number of road accidents, wireless communications have been identified as a promising solutions in this area. This paper presents the simulation results for a Visible Light Communications (VLC) sensor envisioned for vehicular communication applications. Since the outdoor VLC channel can be affected by multiple noise sources, numerical filters and digital signal processing techniques are used as a solution to increase the robustness to noise and to enhance the sensor's flexibility. Simulations are performed in order to analyze the effect of the modulation frequency, SNR and message length on the BER.

As the number of satellites orbiting around the Earth is significantly increasing, it is important to extend the ground station network, in order to be able to receive as much of the satellite transmitted data. In this context, this paper addresses the aspects related to the implementation of a ground station for LEO satellites, located in Suceava city, focusing on the analysis of the reference antenna's parameters using probe signals from satellites that are not stabilized in attitude. The ground station currently uses a 145 and a 436 MHz omnidirectional antenna, with two more antennas and a remote control station under development.