Vehicular Visible Light Communication

This paper presents a novel software-defined radio (SDR) platform designed to measure the bit error rate (BER) in vehicle-to-vehicle visible light communication (V2V VLC) technology under real-world conditions. Unlike previous studies that have primarily relied on simulations or static tests, this research provides empirical evidence from both stationary and dynamic vehicular scenarios. The proposed system functions as an orthogonal frequency division multiplexing (OFDM) transceiver, employing multistate quadrature amplitude modulation (M-QAM) to modulate individual subcarriers. Extensive experiments were conducted to evaluate the system's performance, including the effects of varying headlight beam angles and vehicle distances on BER. Notably, stable communication was achieved using 64-QAM modulation at distances up to 10 meters, maintaining a BER below the critical threshold of 10^-5. These findings demonstrate the feasibility and robustness of integrating VLC with standard vehicle headlight systems, offering a viable solution for enhancing vehicular communication in dynamic traffic environments.

Visible Light Communication (VLC) has the potential to advance Intelligent Transportation Systems (ITS). This study explores the current advancements of VLC in ITS applications that may enhance traffic flow, road safety, and vehicular communication performance. The potential, benefits, and current research trends of VLC in ITS applications are discussed first. Then, the state-of-the-art VLC technologies including overall concept, IEEE communication protocols, hybrid VLC systems, and software-defined adaptive MIMO VLC systems, are discussed. We investigated different potential applications of VLC in ITS, such as signalized intersection and ramp metering control, collision warning and avoidance, vehicle localization and detection, and vehicle platooning using vehicle-vehicle (V2V), infrastructure-vehicle (I2V), and vehicle-everything (V2X) communications. Besides, VLC faces several challenges in ITS applications, and these concerns, e.g., environmental issues, communication range issues, standards and infrastructure integration issues, light conditions and integration issues are discussed. Finally, this paper discusses various advanced techniques to enhance VLC performance in ITS applications, such as machine learning-based channel estimation, adaptive beamforming, robust modulation schemes, and hybrid VLC integration. With this review, the authors aim to inform academics, engineers, and policymakers about the status and challenges of VLC in ITS. It is expected that, by applying VLC in ITS, mobility will be safer, more efficient, and sustainable.

Over the recent few years, optical wireless communication (OWC) has attracted significant attention in both academia and the research community. Contrary to radio frequency (RF) systems, the spatial confinement of the optical beams makes the OWC system a potential system offering higher data rates and secured communication. OWC systems and applications in several areas, such as terrestrial outdoor (free-space optical (FSO) communication), indoor and outdoor visible light communication (VLC), etc. For the terrestrial outdoor FSO systems, spatial diversity techniques are employed over FSO links to enhance the diversity and overall performance. To this end, the spatial diversity techniques corresponding to the state-of-the-art are repetition coding (RC), transmit laser selection (TLS), and orthogonal space-time block codes. Note that, TLS is the optimal transmission scheme in the FSO systems. In this dissertation, we name the conventional TLS scheme as a single TLS (STLS) scheme. However, the performance of the conventional STLS scheme is highly dependent on the feedback errors. On the other side, the outdoor VLC finds applications in vehicle-to-vehicle (V2V) communications, infrastructure-to-vehicle (I2V) communications, etc. Emphasizing the state-of-the-art corresponding to the outdoor V2V-VLC systems, there is a lack of comprehensive modeling and performance investigation under the adverse challenges of the outdoor VLC environment. Moreover, to address the challenges of the next-generation-based outdoor intelligent transportation systems (ITSs), an indoor testbed design for an outdoor I2V-VLC system is still missing.

In order to enhance the diversity and overall performance of the terrestrial outdoor FSO systems, the study begins by proposing two novel TLS schemes. We call the proposed schemes as two TLS (TTLS) and modified error-tolerant weighting scheme iii (METWS). Note that, the conventional STLS scheme gives optimal performance under a perfect feedback scenario. However, its performance degrades significantly under an imperfect feedback scenario. To this end, the two proposed schemes overcome the practical limitations of the conventional STLS scheme. Moreover, we analyze the performance of the two proposed schemes for both perfect and imperfect channel state information (CSI)-based communication scenarios. Further, different performance metrics, such as bit error rate (BER), diversity gain, etc., are thoroughly analyzed. Furthermore, to gain more insights, the performance of the two proposed schemes is also compared with the conventional STLS and RC schemes.

We then investigate the diversity-multiplexing tradeoff (DMT) for the OWC systems. To this end, we mainly focus on the indoor VLC and outdoor FSO systems. For the DMT investigation of the indoor VLC system, we consider the random radial movement of the end-user in the proposed system model. The optimal DMT for both the single-input single-output (SISO) and multiple-input multiple-output (MIMO) VLC systems are analyzed. Novel analytical expressions for the probability distribution function (PDF), outage probability, and outage diversity order for the SISO-VLC and MIMO-VLC systems are derived. Moreover, we extend our study to the outdoor FSO system. For the first time in literature, a limited feedback-based DMT is investigated for the FSO system under different transmission scenarios. To this end, we consider a MIMO-FSO setup and investigate the DMT for single-rate and adaptive-rate trans mission scenarios.

Further, we venture into the area of vehicular VLC and comprehensively explore the area of vehicular VLC. To this end, contrary to the state-of-the-art, we emphasize comprehensive modeling of the V2V-VLC system under the practical challenges of an outdoor VLC environment. For the first time, we model the vehicle's mobility as random with a specific PDF. Therefore, we emphasize a more realistic approach to model the vehicle's mobility. Moreover, a novel channel model that incorporates the joint impact of the outdoor V2V-VLC random path loss and atmospheric turbulence (AT) is emphasized. Further, different performance metrics are analytically examined, such as path loss, outage probability, average BER (ABER), diversity order, discrete-input continuous-output memoryless channel (DCMC) capacity, etc., under different weather conditions.

We also extend our work on vehicular VLC by proposing a shadowing/blocking-based V2V-VLC model. In a line-of-sight (LOS) VLC system, the communication link is exposed to temporary shadowing due to physical obstructions by vehicles in the same lane or nearby parked vehicles. Since VLC is highly dependent on the LOS, proposing and analyzing a V2V-VLC model under a shadowing-based transmission scenario is of extreme importance. The performance of the proposed V2V-VLC model is analyzed with the DMT metric. Moreover, to minimize the path loss at the receiver (Rx), a novel hemispherical optical concentrator-based Rx structure (offering an omnidirectional gain) is also proposed. Some striking insights are envisioned for the proposed work.

Finally, as a part of the next-generation-based ITSs, we also develop an indoor testbed for an outdoor I2V-VLC system. For the first time in literature, we experimentally demonstrate the communication between the traffic light acting as the transmitter (Tx) and the camera (i.e., the Rx) under different realistic I2V-VLC scenarios in a controlled indoor environment. Moreover, all the experimental findings are demonstrated for different exposure times of the camera for the first time, which is a very critical parameter when using a camera-based Rx. Further, different performance metrics are experimentally examined, such as BER, peak signal-to-noise ratio (PSNR), and capacity. Furthermore, LOS blockage-based communication scenarios are also experimentally analyzed.

Vehicle-to-vehicle (V2V) communication is crucial in platooning configurations to ensure lateral and longitudinal control of the vehicle trajectory and thus must be reliable. Though radio frequency (RF) systems are widely used for their numerous qualities, their performances can be severely degraded in dense traffic scenario. Visible light communication (VLC), which is not as sensible, could be used as a complementary technology. In this work, a simple and low-cost VLC system suitable for V2V communications is presented. An off-the-shelf central stop lamp, composed of six low-power light-emitting diodes (LED), is used as emitter whereas a photodiode (PD) coupled with an analog processing circuit is used as receiver. This system provides, at a rate of 100 kbps and without errors, a packet delivery ratio (PDR) of 100% over 4.5 m and 77% over 6 m while keeping the transmission latency under 6 ms and is thus compatible with platooning applications.

As the Visible Light Communications (VLC) is growing up, it is not restricted anymore to the traditional indoor applications such as LiFi or positioning, but it finds new customers at outdoor vendors like underwater and vehicle applications. In this paper we looked at VLC challenges in Vehicular Communications from Medium Access Control point of view. We proposed Link Adaptive Protocol where a single handshake association and fast handover algorithms prolong VLC connectivity. Moreover, adaptive modulation has been suggested in order to increase the throughput. Simulation results show the link adaptive protocol outperforms slotted-aloha in outage probability and goodput, properly achieving a trade-off between pilot rate and protocol efficiency.

In this work, a vehicle-to-vehicle (V2V) visible light communications (VLC) model for two practical scenarios, is proposed. In scenario 1, the random lateral shift of vehicles and the deterministic longitudinal separation between two communicating vehicles are considered, whereas in scenario 2, longitudinal separation between two vehicles is considered to be random, and lateral shift of vehicles is considered to be deterministic. To this end, we emphasize comprehensive modeling of the practical characteristics of the considered V2V-VLC system, such as random path loss due to the random mobility of the vehicle, random lateral shift and random longitudinal separation of the vehicle. Moreover, we analyze the performance of the proposed V2V-VLC model in terms of different metrics under the consideration of a novel channel model. Considering our findings, it is observed that the random lateral shift of the vehicle and the random longitudinal separation between two vehicles have a significant impact on the V2V-VLC system performance. Further, at a distance of 40 m, for example, the path loss penalties for moderate and dense fog weather scenarios are 2 and 3 dB, respectively, compared with the clear weather. Furthermore, the combined impact of path loss and atmospheric turbulence affects the V2V-VLC performance significantly.

Vehicular Visible light communication (VLC) technology has recently attracted much interest from researchers and scientists. This technology enables connectivity between vehicles and infrastructures along the road by using vehicles' headlights and taillights as wireless transmitters. The reliability of vehicleto-vehicle (V2V) VLC systems is affected by several factors, such as car mobility, optics system design, and visibility conditions, where the first two have the most impact on the VLC system performance. This paper, therefore, focuses on the relative positions of the cars and the design of the optics, especially on the receiving end, which has been proposed with the use of a polar detector instead of the rectangular detectors commonly used in the literature. We investigate the achievable gain compared to the conventional detector for different vehicle locations, utilizing a professional optical system design and ray tracing approach. Then, to improve the performance, we introduce the utilization of an imaging receiver by integrating the polar detector with different optical commercial lens combinations, such as Fresnel and Aspherical lenses. To further improve the V2V system performance, we propose a novel optical lens combination design by integrating double-convex lens with half-Plano-concave lens, which allows the correction of more optical aberrations, such as chromatic and spherical aberration. Utilizing the non-sequential ray tracing tools, we designed these VLC systems and perform a realistic channel modeling study considering the typical 3D CAD models of vehicles and roads as well as the possibility of horizontal and vertical movement between the vehicles. Based on the channel impulse responses (CIRs) obtained from the ray tracing simulations, we analyzed the performance of V2V VLC systems with all lens combinations at different vehicle positions on the road. We further investigated the impact of different system parameters on the overall V2V system performance, such as receiver diameter and bandwidth. The obtained results demonstrated that with a carefully chosen system and lens parameters, the proposed system design of lens combination provides an enhancement of up to 7 dB in total received power compared to the case without a lens. Our results also revealed that the proposed system design outperforms the benchmark ones for all lateral displacements and longitudinal distances.

Visible Light Communications (VLC) can play an important role in the Cooperative Intelligent Transport Systems (C-ITS) by enabling vehicles to communicate with nearby vehicles (V2V) and infrastructure (V2I) by offering virtually unlimited and unregulated spectrum. Whereas extensive R&D efforts have been made on physical layer techniques, almost no study has been made on Multi-Users Interference (MUI), consequently Medium Access Control (MAC), in VLC. This work sheds light on the impacts of MUI on VLC performances for V2V communications. We first develop an analytical model that formulates the Packet Delivery Ratio (PDR) performances of VLC communication in presence of MUI. We then conduct simulation evaluations to confirm the analytical model and evaluate the VLC performance when there is one or more interfering nodes. The obtained results clearly show that, in an absence of MAC, VLC can suffer from MUI in medium to dense traffic density even when message generation rate at each node is relately low.

Visible light communication (VLC) has been recently proposed as an alternative standard to radio-based wireless networks. Originally developed as a physical media for PANs (Personal area Networks) it evolved into universal WLAN technology with a capability to transport internet suite of network and application level protocols. Because of its physical characteristics, and in line with the slogan "what you see is what you send", VLC is considered a secure communication method. In this work we focus on security aspects of VLC communication, starting from basic physical characteristics of the communication channel. We analyze the risks of signal jamming, data snooping and data modification. We also discuss MAC-level security mechanisms as defined in the IEEE 802.15.7 standard. This paper is an extension of work originally reported in Proceedings of the 13th IFAC and IEEE Conference on Programmable Devices and Embedded Systems - PDES 2015

This document is the author's post-print version, incorporating any revisions agreed during the peer-review process. Some differences between the published version and this version may remain and you are advised to consult the published version if you wish to cite from it.

VIsible light communication for advanced Driver Assistant Systems (VIDAS) is an outdoor application using the visible spectrum of light emitting diodes (LED). A simple traffic light set up based on LED traffic lights for traffic information transmission has been analyzed in this paper. Various important design parameters have been optimized through intensive investigation based on gain variation over 100 m of transmission range. This process is expected to simplify the front-end receiver design and enhance the performance of the ...

VIsible light communication for advanced Driver Assistant Systems (VIDAS) is an outdoor application using the visible spectrum of light emitting diodes (LED). A simple traffic light set up based on LED traffic lights for traffic information transmission has been analyzed in this paper. Various important design parameters have been optimized through intensive investigation based on gain variation over 100 m of transmission range. This process is expected to simplify the front-end receiver design and enhance the performance of the ...

VIsible light communication for advanced Driver Assistant Systems (VIDAS) is an outdoor application using the visible spectrum of light emitting diodes (LED). A simple traffic light set up based on LED traffic lights for traffic information transmission has been analyzed in this paper. Various important design parameters have been optimized through intensive investigation based on gain variation over 100 m of transmission range. This process is expected to simplify the front-end receiver design and enhance the performance of the ...

VIsible light communication for advanced Driver Assistant Systems (VIDAS) is an outdoor application using the visible spectrum of light emitting diodes (LED). A simple traffic light set up based on LED traffic lights for traffic information transmission has been analyzed in this paper. Various important design parameters have been optimized through intensive investigation based on gain variation over 100 m of transmission range. This process is expected to simplify the front-end receiver design and enhance the performance of the ...

The IEEE has established the standardization group 802.15.7r1 "Short Range Optical Wireless Communications", which is currently in the process of developing a standard for visible light communication (VLC). As with any other communication system, realistic channel models are of critical importance for VLC system design, performance evaluation, and testing. This article presents the reference channel models that were endorsed by the IEEE 802.15.7r1 Task Group for evaluation of VLC system proposals. These were developed for typical indoor environments, including home, office, and manufacturing cells. While highlighting the channel models, we further discuss physical layer techniques potentially considered for IEEE 802.15.7r1.

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 t...

Visible Light Communication (VLC) technology have recently been suggested as efficient supportive technology for platooning applications over short inter-vehicle distances. Though, ensuring the continuity of Line-of-Sight (LOS) of any optical-based applications is one of the most complex scenarios for an autonomous vehicle control, and still remains as an open challenge for Intelligent Transformation Systems (ITS). Exchanging information about the relative directional position of each member of the platoon, together with front and rear facing directions of each vehicle, can be very useful data for building a smooth geometrical-based compensation method, which results in ensuring that any increase in both incidence and irradiance optical angles will never exceed the Field of View (FOV) limitations and regardless of the trajectory shape. This paper propose a tracking alike compensation method of four vehicles equipped with positioning and VLC systems. We have simulated different scenarios related to different trajectories and compensation angles limits. The simulation results show that trajectories influence on the optical incidence and irradiance angles can be compensated efficiently and without deploying any tracking method.

The major benefits of driving vehicles in controlled close formations such as platoons are that of increasing traffic fluidity and reducing air pollution. While V2V communications is requisite for platooning stability, the existing radio communications technologies (e.g., the IEEE 802.11p) suffer from poor performance in highly dense road scenarios, which are exactly to be created by platooning. This paper studies the applicability of visible light communications (VLC) system for information exchange between the platoon members. A complete VLC model is built enabling precise calculations of Bit-Error-Rate (BER) affected by inter-vehicle distance, background noise, incidence angle and receiver electrical bandwidth. Based on our analytical model, the optical parameters suiting platooning application are defined. Finally, a SIMULINK model is developed to study the performances of a platooning longitudinal and lateral control, where VLC is used for vehicle-to-vehicle information exchange. Our study demonstrates the feasibility of VLC-based platooning control even in the presence of optical noise at significant levels and up to certain degree of road curvature. CONFIDENTIAL. Limited circulation. For review only.

Robust, efficient, secure, and low-cost vehicle-tovehicle (V2V) visible light communication (VLC) protocols, with high transmission rates, are very appealing to alleviate high traffic and to diminish air pollution in high vehicle density environments. In contrast to radio frequency (RF) protocols, where a stable communication cannot be ensured in highly dense road scenarios, VLC has emerged as a revolutionary alternative for the control of road traffic and prevention of accidents. Although last years have witnessed an increasing interest in this subject, VLC is still considered to be in the early phase of research (with several drawbacks to be faced). In this paper is analyzed a cooperative dual-hop visible light network operating with half-duplex and full-duplex protocols in a scenario subject to environmental interference of other vehicle. In particular, we considered four vehicles being the source, the destination, a relay and a potential interferer. The system performance is evaluated considering the bit error rate (BER), and throughput metrics. The results show that the cooperative communication is an effective solution for scenarios where it is not possible a direct transmission between source and destination. Numerical results are compared for the cases with and without interferences in order to show the impacts of interference in the proposed cooperative VLC schemes.

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Vehicular Visible Light communication (VVLC) presents a new paradigm for providing vehicle connectivity, increasing road safety, and achieving autonomous driving. It can be chosen as an alternative solution to radio frequency-based inter-vehicle communication systems and/or as a complementary solution to ensure redundancy. Nevertheless, there are still significant challenges in incorporating visible light communication systems into vehicular networks. The main purpose of this paper is to provide an outline of the performance metrics of a VVLC system. Furthermore, the study is performed based on a vehicle-to-vehicle dynamic model close to reality, considering the effect of geometrical changes in the LOS path and the variation of the inter-vehicular distance. The analysis of the proposed system is discussed in terms of Signal to noise (SNR), Field of view (FOV), mobility, and average capacity.

This paper proposes a hybrid communication system for Intelligent Transportation System (ITS) utilizing visible light and radio communications for position-based services. The directionality of light communication is used to distribute positionbased keys to vehicles such that they can extract information related only to their desired lanes. The extended coverage of radio communication is used to provide stable data communication complementing the visible light communications (VLC) systems. This paper provides system models and important parameters for designing a hybrid ITS system. The system performance is evaluated by simulation, and the results demonstrate a considerable increase of the effective communication area and receivable information using the proposed hybrid ITS system compared with a VLC system.

Vehicular Visible Light communication (VVLC) presents a new paradigm for providing vehicle connectivity, increasing road safety, and achieving autonomous driving. It can be chosen as an alternative solution to radio frequency-based inter-vehicle communication systems and/or as a complementary solution to ensure redundancy. Nevertheless, there are still significant challenges in incorporating visible light communication systems into vehicular networks. The main purpose of this paper is to provide an outline of the performance metrics of a VVLC system. Furthermore, the study is performed based on a vehicle-to-vehicle dynamic model close to reality, considering the effect of geometrical changes in the LOS path and the variation of the inter-vehicular distance. The analysis of the proposed system is discussed in terms of Signal to noise (SNR), Field of view (FOV), mobility, and average capacity.

Relative vehicle positioning methods can contribute to safer and more efficient autonomous driving in the future by enabling collision avoidance and platooning applications. For full automation, these applications require cm-level positioning accuracy and greater than 50 Hz update rate. Since sensorbased methods (e.g., LIDAR, cameras) have not been able to reliably satisfy these requirements under all conditions so far, complementary methods are sought. Recently, alternative methods that use visible light communication (VLC) signals from vehicle head/tail LED lights for positioning (VLP) have shown significant promise, attaining cm-level accuracy and near-kHz rate in realistic driving scenarios. These methods estimate position in two steps: 1) Relative transmitter bearings (angle) or ranges (distance) are measured based on received VLC signals, and 2) these measurements are combined to estimate relative positions of transmitters (i.e., head/tail lights). In this survey paper, we first review existing bearing/range measurement techniques and positioning algorithms for vehicular VLP. Next, we formulate two new positioning algorithms: One based on consecutive range measurements from a single receiver, and another one based on differential bearing measurements from two receivers. We analyze the performance of all methods by deriving their respective Cramer-Rao lower bounds on positioning accuracy (CRLB) and simulating them in realistic driving scenarios with challenging noise and weather conditions. Our results show that VLP methods can indeed satisfy the accuracy and rate requirements for localization in collision avoidance and platooning applications. Finally, we discuss remaining open challenges that are faced for the deployment of VLP solutions in the automotive sector.

Relative vehicle positioning methods can contribute to safer and more efficient autonomous driving in the future by enabling collision avoidance and platooning applications. For full automation, these applications require cm-level positioning accuracy and greater than 50 Hz update rate. Since sensorbased methods (e.g., LIDAR, cameras) have not been able to reliably satisfy these requirements under all conditions so far, complementary methods are sought. Recently, alternative methods that use visible light communication (VLC) signals from vehicle head/tail LED lights for positioning (VLP) have shown significant promise, attaining cm-level accuracy and nearkHz rate in realistic driving scenarios. These methods estimate position in two steps: 1) Relative transmitter bearings (angle) or ranges (distance) are measured based on received VLC signals, and 2) these measurements are combined to estimate relative positions of transmitters (i.e., head/tail lights). In this survey paper, we firs...

Visible Light Communications (VLC) can play an important role in the Cooperative Intelligent Transport Systems (C-ITS) by enabling vehicles to communicate with nearby vehicles (V2V) and infrastructure (V2I) by offering virtually unlimited and unregulated spectrum. Whereas extensive R&D efforts have been made on physical layer techniques, almost no study has been made on Multi-Users Interference (MUI), consequently Medium Access Control (MAC), in VLC. This work sheds light on the impacts of MUI on VLC performances for V2V communications. We first develop an analytical model that formulates the Packet Delivery Ratio (PDR) performances of VLC communication in presence of MUI. We then conduct simulation evaluations to confirm the analytical model and evaluate the VLC performance when there is one or more interfering nodes. The obtained results clearly show that, in an absence of MAC, VLC can suffer from MUI in medium to dense traffic density even when message generation rate at each nod...

Vehicular Visible Light communication (VVLC) presents a new paradigm for providing vehicle connectivity, increasing road safety, and achieving autonomous driving. It can be chosen as an alternative solution to radio frequency-based inter-vehicle communication systems and/or as a complementary solution to ensure redundancy. Nevertheless, there are still significant challenges in incorporating visible light communication systems into vehicular networks. The main purpose of this paper is to provide an outline of the performance metrics of a VVLC system. Furthermore, the study is performed based on a vehicle-tovehicle dynamic model close to reality, considering the effect of geometrical changes in the LOS path and the variation of the inter-vehicular distance. The analysis of the proposed system is discussed in terms of Signal to noise (SNR), Field of view (FOV), mobility, and average capacity.

The visible light communication (VLC) systems are generally considered secure since the light cannot penetrate through solid objects. However, both in the line of sight (LoS) scenarios as well as in non LoS scenarios with wide and strong optical signal, information security must be considered. The conventional information security technologies used for wireless communications based on radio frequency are not suitable to be applied straight for VLCs because of the limited hardware resources, especially for the optical receivers (oRx). In this paper, a study on the VLC security at the physical layer approach based on optical beamforming to achieve secure transmissions for indoor and underground scenarios is presented.

VIsible light communication for advanced Driver Assistant Systems (VIDAS) is an outdoor application using the visible spectrum of light emitting diodes (LED). A simple traffic light set up based on LED traffic lights for traffic information transmission has been analyzed in this paper. Various important design parameters have been optimized through intensive investigation based on gain variation over 100 m of transmission range. This process is expected to simplify the front-end receiver design and enhance the performance of the ...

Visible Light Communication (VLC) has recently been proposed as a low-cost and low-complexity technology for vehicular communications. In this paper, we propose the usage of dual channel VLC with the goal of providing enhanced vehicular connectivity to disseminate safety-critical messages and perform an experimental study to determine the spatial and angular limits of an off-the-shelf automotive Light Emitting Diode (LED) fog light. Single channel VLC refers to the independent transmission of different data packets from each LED fog light, while the dual channel VLC offers the concurrent transmission of the same data packet from both lights. There is a trade-off between increasing the angular limitation and the performance of dual channel VLC, which needs to be experimentally evaluated to identify its efficient usage. We first show the dependency of the received optical power of single channel VLC on the angle and distance, and demonstrate that Lambertian model does not represent the automotive LED fog light radiation pattern accurately. We then demonstrate that dual channel usage increases the angular limitation by up to 10° compared to the single channel VLC. We also show that dual channel improves the packet delivery error rate performance at only short distances due to the photodiode (PD) saturation led by light intensity overlapping at higher distances.

a variety of challenging telecommunication topics ranging from background fields like signals, traffic, coding, communication basics up to large communication systems and networks, fixed, mobile and integrated, etc. Applications, services, system and network management issues also received significant attention. We are witnessing many technological paradigm shifts imposed by the complexity induced by the notions of fully shared resources, cooperative work, and resource availability. P2P, GRID, Clusters, Web Services, Delay Tolerant Networks, Service/Resource identification and localization illustrate aspects where some components and/or services expose features that are neither stable nor fully guaranteed. Examples of technologies exposing similar behavior are WiFi, WiMax, WideBand, UWB, ZigBee, MBWA and others. Management aspects related to autonomic and adaptive management includes the entire arsenal of self-ilities. Autonomic Computing, On-Demand Networks and Utility Computing to...