Vehicular Applications Research Articles

DRL-based Resource Management in Network Slicing for Vehicular Applications

Network Slicing (NS) was proposed as a viable solution in Release 15 of Third Generation Partnership Project (3GPP) to allocate the limited resources among different service types for improving their Quality-of-Service (QoS). However, the advanced vehicular applications such as autonomous driving, platooning, remote driving, etc. have stringent QoS demands and the standard NS architecture is not sustainable for these services. Therefore, we propose a solution compatible with the standard 3GPP NS architecture that implements an Actor-Critic based Deep Reinforcement Learning (DRL) algorithm in the Network Slice Subnet Management Function (NSSMF). The algorithm allocates and manages the limited resources among different slices based on their real-time traffic demands. We generate real-time traffic for each service type and train the algorithm to improve the QoS of each service type in the network. The proposed method is evaluated for the training performance of the proposed algorithm as well as the Service level agreement Satisfaction Ratio (SSR) of each slice. The results exhibit that the proposed method not only improves SSR of each slice, but also performs well in case of increased node density in the network.

Radio wave propagation analysis with dominant path model using MIMO antenna element for vehicular base station application

AbstractA low-profile slant ±45° polarized antenna for a 4G/5G base station with a dominant path wave propagation model (DPM) is reported in this paper. For dual-polarization and wide impedance bandwidth, the two dipole radiators are crisscrossed and a square metallic ring is integrated with the dipole arms and screwed with the four shorting vias. The antenna operates in Band 40/41/42/43 with strong isolation and low ECC (Envelop Correlation Coefficient). Fabricated antenna results show that the predicted wideband antenna has 13.38% bandwidth in 4G, which is Band 40/41, and 29.33% bandwidth in 5G sub-6 GHz Band 42/43. The antenna has a consistent radiation pattern, a 40 dB XPD (Cross Pol Discrimination), and a beam width of 69.5° ±1.5° in the entire frequency band. Three base station sites were explored to deploy the radiation pattern of a dual-polarized antenna in the 3D EM (Electromagnetic Analysis) tool. To evaluate signal quality, strength, radio network planning, and wave propagation analysis by analyzing antenna performance in real-time scenarios with 64 and 256 QAM (Quadrature Amplitude Modulation) techniques. For the proposed four-stream MIMO (Multiple-Input-Multiple-Output) antenna arrangement at deployed cell sites for 4G/5G base station applications, the maximum downlink and uplink data rates are 3.826/2.8 Mbps and 1044/800 Mbps respectively.

Visible light communication for vehicular applications: A novel architecture with proof-of-concept prototype

When there is an increasing interest in visible light communication (VLC), outdoor vehicle VLC has emerged as a promising candidate technology for future intelligent transportation systems. However, in VLC based vehicular applications, several challenges impede successful commercial application of VLC based products. This article first provides a thorough overview of the existing challenges. To overcome these challenges, we propose a novel architecture with tracking and environment sensing ability for practical vehicular applications. Moreover, aproof-of-concept prototype is implemented to validate the feasibility of the proposed system. Experimental and simulation results show that the proposed VLC system can provide reliable communications with a bit-error rate less than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−4</sup> for vehicles under strong interference lights. Finally, based on the evaluations, we propose some key design issues for future studies in this research area.

Start-Up Charging Strategy for a Large-Format NMCA/Graphite Pouch Cell from Subzero Temperature Using an Electrochemical, Thermal, and Mechanical Life Model

Start-up strategy of battery pack in vehicular applications is crucial to secure the performance of the battery system, particularly at subzero temperatures. In this paper, a new strategy for cold start-up is proposed using an electrochemical, thermal, and mechanical life model. Especially, the conventional mechanical model that requires complex multi-dimensional lithium-ion concentration is simplified to reduce the computational cost. The developed model is experimentally validated with voltage responses at −10 °C under various current profiles, which predicts capacity fade by chemical and mechanical degradation. Further analysis is performed using the model, which provides the detailed mechanisms of the degradation. Finally, a new charging algorithm targeting the start-up strategy at subzero temperature is developed. The proposed profile consists of discharge pulses applied at the start to stimulate the increase of the battery temperature and then charging current that optimally minimizes the capacity fade and charging speed. The pulse parameters and charging current profile are optimized using Genetic algorithm and nonlinear model predictive control, respectively. The algorithm is implemented in a battery-in-the-loop system and compared with CC/CV charging methods from a subzero temperature. The results of the new method have shown improved charging efficiency and cycle life.

Latency-Sensitive Task Allocation for Fog-Based Vehicular Crowdsensing

The development of the Internet of Vehicles has attracted a large number of innovative vehicular applications. Specifically, vehicular crowdsensing represents an emerging paradigm that utilizes on-board sensing and computing capacity to provide location-based services. The conventional vehicular crowdsensing method aims to improve the quality of service or reduce the cost while guaranteeing coverage and data quality. Inappropriate sensing vehicle selection may cause high execution latency, which, however, has rarely been considered. In this article, we propose a fog-based vehicular crowdsensing scheme, where on-board sensors can act as sensing participants and vehicles can act as fog nodes. It unifies crowdsensing participant selection and computing task allocation to jointly optimize execution latency and cost. Furthermore, we present a heuristic algorithm named as random chemical reaction optimization (RCRO) to solve the proposed problem. Finally, we evaluate the proposed scheme and algorithm by simulating real-world traffic. Numerical results show the performance of the RCRO algorithm and the superiority of the proposed method in comparison with the conventional method.

Tangential Force Noise Reduction of Vehicular PMSM Based on Reference Harmonic Current Analytical Computation

The harmonic current injection can remarkably reduce the noise of the vehicular electric drive system. However, the optimal reference harmonic current is difficult to obtain because of the vehicular motor’s non-linear electromagnetic characteristics. The existing methods are always time-consuming and cannot satisfy the real-time requirement of the vehicular application. This article proposed an analytical computation method of the reference harmonic current for tangential force noise reduction. Specifically, by combining two-dimensional Fourier series decomposition and polynomial fitting, a data-based non-linear model is constructed to accurately describe the tangential force harmonic under arbitrary current excitation. Then, considering the dominant effect of fundamental current, a simplified tangential force model is obtained by local linearization at each fundamental current working point. Meanwhile, by representing the stator current amplitude with a Fourier series combination, the suppression of tangential force harmonics is transferred to solving linear equations concerning each harmonic current vector. Finally, simulation and bench test experiments have been done to verify the effectiveness of the proposed method. The results demonstrate that the reference harmonic current at different speeds/torque can be computed in real-time, and the corresponding tangential noise can be reduced remarkably.

An improved AAPI controller for enhanced DC-link transient performance of six-phase active rectifier application

The permanent magnet synchronous generators (PMSGs), especially those with multi-phase structure, are increasingly adopted to power large-scale vehicular system with DC distribution (e.g. more electric aircraft and electric-propulsion ship). The controller design is critical in these vehicular application as they are required to maintain desired transient performance under large system disturbances. In this paper, an improved adding a power integrator (AAPI) controller is designed and adopted to regulate the six-phase active rectifier, thus enhancing the transient performance of the system. The regulation of the multi-phase active rectifier feeding large amount of dynamic instantaneous constant power load (CPL) is firstly formulated as a second-order system by utilizing a bi-linear coordinate transformation. Then, an improved AAPI finite-time controller is designed considering both asymptotic stability and the transient stability of the system. Last but not least, the effectiveness of the proposal is validated by simulation.

A Review on Image Sensor Communication and Its Applications to Vehicles

Image sensor communication (ISC), also known as optical camera communication, is a form of visible light communication that utilizes image sensors rather than a single photodiode, for data reception. ISC offers spatial separation properties and robustness to ambient noise, making it suitable for outdoor applications such as intelligent transportation systems (ITSs). This review analyzes the research trends in ISC, specifically concerning its application in ITSs. Our focus is on various ISC receivers, including rolling shutter cameras, global shutter high-speed cameras, optical communication image sensors, and event cameras. We analyze how each of these receivers is being utilized in ISC vehicular applications. In addition, we highlight the use of ISC in range estimation techniques and the ability to achieve simultaneous communication and range estimation. By examining these topics, we aim to provide a comprehensive overview of the role of ISC technology in ITSs and its potential for future development.

V-SLAM ENHANCED INS/GNSS FUSION SCHEME FOR LANE LEVEL VEHICULAR NAVIGATION APPLICATIONS IN DYNAMIC ENVIRONMENT

Abstract. With the development of different sensors, such as global navigation satellite system (GNSS), inertial measurement unit (IMU), LiDAR, radar and camera, more localization information is available for autonomous vehicular applications. However, each sensor has its limitations in different circumstances. For example, visual Simultaneous Localization and Mapping (SLAM) easily loses tracking in an open sky area where accurate GNSS measurements can be obtained. Sensors can complement each other by integrated their information in a multi-sensor fusion scheme. In this study, we proposed a visual-SLAM enhanced INS/GNSS localization fusion scheme for a high dynamic environment. Oriented FAST and rotated BRIEF (ORB) SLAM are used to pre-process image sequences from monocular camera, rescaled and refreshed after applying GNSS measurements, and convert to position and velocity information, which can provide updates to the system. The performance of the fusion system was verified through two field tests at different speed ranges (about 30–60 km/s), using a reliable reference system as ground-truth to assess the accuracy of the proposed localization fusion scheme. The results indicated that the proposed system could improve the navigation accuracy compared to INS/GNSS integration scheme and achieve which-lane level or even where-in-lane level.

On the Impact of Multiple Access Interference in LTE-V2X and NR-V2X Sidelink Communications

Developing radio access technologies that enable reliable and low-latency vehicular communications have become of the utmost importance with the rise of interest in autonomous vehicles. The Third Generation Partnership Project (3GPP) has developed Vehicle to Everything (V2X) specifications based on the 5G New Radio Air Interface (NR-V2X) to support connected and automated driving use cases, with strict requirements to fulfill the constantly evolving vehicular applications, communication, and service demands of connected vehicles, such as ultra-low latency and ultra-high reliability. This paper presents an analytical model for evaluating the performance of NR-V2X communications, with particular reference to the sensing-based semi-persistent scheduling operation defined in the NR-V2X Mode 2, in comparison with legacy sidelink V2X over LTE, specified as LTE-V2X Mode 4. We consider a vehicle platooning scenario and evaluate the impact of multiple access interference on the packet success probability, by varying the available resources, the number of interfering vehicles, and their relative positions. The average packet success probability is determined analytically for LTE-V2X and NR-V2X, taking into account the different physical layer specifications, and the Moment Matching Approximation (MMA) is used to approximate the statistics of the signal-to-interference-plus-noise ratio (SINR) under the assumption of a Nakagami-lognormal composite channel model. The analytical approximation is validated against extensive Matlab simulations that a show good accuracy. The results confirm a boost in performance with NR-V2X against LTE-V2X, particularly for high inter-vehicle distance and a large number of vehicles, providing a concise yet accurate modeling rationale for planning and adaptation of the configuration and parameter setup of vehicle platoons, without having to resort to extensive computer simulation or experimental measurements.

A Multi-Agent Deep Reinforcement Learning-Based Popular Content Distribution Scheme in Vehicular Networks.

The Internet of Vehicles (IoV) enables vehicular data services and applications through vehicle-to-everything (V2X) communications. One of the key services provided by IoV is popular content distribution (PCD), which aims to quickly deliver popular content that most vehicles request. However, it is challenging for vehicles to receive the complete popular content from roadside units (RSUs) due to their mobility and the RSUs' constrained coverage. The collaboration of vehicles via vehicle-to-vehicle (V2V) communications is an effective solution to assist more vehicles to obtain the entire popular content at a lower time cost. To this end, we propose a multi-agent deep reinforcement learning (MADRL)-based popular content distribution scheme in vehicular networks, where each vehicle deploys an MADRL agent that learns to choose the appropriate data transmission policy. To reduce the complexity of the MADRL-based algorithm, a vehicle clustering algorithm based on spectral clustering is provided to divide all vehicles in the V2V phase into groups, so that only vehicles within the same group exchange data. Then the multi-agent proximal policy optimization (MAPPO) algorithm is used to train the agent. We introduce the self-attention mechanism when constructing the neural network for the MADRL to help the agent accurately represent the environment and make decisions. Furthermore, the invalid action masking technique is utilized to prevent the agent from taking invalid actions, accelerating the training process of the agent. Finally, experimental results are shown and a comprehensive comparison is provided, which demonstrates that our MADRL-PCD scheme outperforms both the coalition game-based scheme and the greedy strategy-based scheme, achieving a higher PCD efficiency and a lower transmission delay.

Design and Modeling of Hybrid Electric Vehicle Powered by Solar and Fuel Cell Energy with Quadratic Buck/Boost Converter

Considering technological advancements and international standards mandating reduced greenhouse gas emissions, automobile manufacturers have shifted their focus toward innovative technologies related to fuel-cell electric vehicles. Despite having an all-electric powertrain, fuel cell electric vehicles (FCEVs) utilize a fuel cell stack as their energy source, which runs on hydrogen and results in the emission of only water and heat. Due to the absence of tailpipe pollutants, fuel-cell electric vehicles are considered zero-emission vehicles. Among fuel cell types, low-temperature and low-pressure fuel cells, such as Proton Exchange Membrane Fuel Cells (PEMFCs), are well-suited for vehicular applications as they exhibit high power density, operate at lower temperatures (60-80°C), and are less prone to corrosion than other types of fuel cells. The main objective of this paper is to investigate solar-assisted electric fuel cell vehicles that efficiently integrate the fuel cell system with an electrolyzer and solar power to fulfill the fluctuating power demands of the electric motor and auxiliary systems. A novel EV configuration with a fuel cell, electrolyzer and onboard PV cell is proposed. An onboard PV cell can assist the fuel cell when the irradiation is enough to generate the power. During the idle conditions of vehicles, PV-generated power can be converted into chemical energy using an electrolyzer and generated hydrogen can be stored in a hydrogen tank. To match the voltage required by the motor and sources a quadratic bidirectional buck-boost converter is employed. The proposed configuration is examined by considering variable irradiance and variable speed values. To obtain the maximum power output from the photovoltaic (PV) panel, a Maximum Power Point Tracking (MPPT) algorithm is employed to regulate the PV system. To enhance the efficiency and cost-effectiveness of PV systems, an enhanced version of the incremental conductance algorithm is utilized as the MPPT control strategy. Outer voltage and inner current control are adopted to regulate the DC output voltage of the QBBC converter. An indirect vector-controlled induction motor is used as vehicle drive. Simulations are performed to investigate the proposed EV configuration in MATLAB/SIMULINK.

Pushing the limits of sodium borohydride hydrolysis for on-board hydrogen generation systems

Sodium borohydride (SBH) is a promising hydrogen (H2) carrier; however, its successful deployment has been limited to unmanned aerial vehicle applications. We reevaluated SBH hydrolysis for on-board vehicular applications from an entirely new perspective using solid-phase SBH hydrolysis with a CO2-derived acid at elevated temperatures and pressures, enabling extremely efficient water utilization. This strategy afforded a high H2 storage density of 6.33 wt%, which could be extended to 10.4 wt% via water recovery from fuel cells. High-purity H2 with carbon monoxide levels below 10 ppm was obtained after methanation. Importantly, an energy-efficient SBH regeneration method using residual NaHCO2 was developed. A 1.2-kWe-level SBH hydrogen generation was evaluated with the fuel-cell operation, and a 20-kWe-level compact system was developed with a system-based volumetric H2 storage density of 25 g-H2/L. This technology will accelerate SBH-based vehicular applications at a level of 50 g-H2/L.

Toward the Age of Intelligent Vehicular Networks for Connected and Autonomous Vehicles in 6G

Twenty-two years after the advent of the firstgeneration vehicular network, i.e., dedicated short-range communications (DSRC) standard/IEEE 802.11p, the vehicular technology market has become very competitive with a new player, Cellular Vehicle-to-Everything (C-V2X). Currently, C-V2X technology likely dominates the race because of the big advantages of comprehensive coverage and high throughput/reliability. Meanwhile, DSRC-based technologies are struggling to survive and rebound with many hopes betting on success of the secondgeneration standard, IEEE P802.11bd. While the standards battle to attract automotive makers and dominate the commercial market landing, the research community has started thinking about the shape of the next-generation vehicular networks. This article details the state-of-the-art progress of vehicular networks, particularly the cellular V2X-related technologies in specific use cases, compared to the features of the current generation. Through the typical examples, we also highlight why 5G is inadequate to provide the best connectivity for the vehicular applications and then 6G technologies can fill up the vacancy.

Tex Se1- x Photodiode Shortwave Infrared Detection and Imaging.

Short-wave infrared detectors are playing an increasingly important role in the fields of autonomous driving, food safety, disease diagnosis and scientific research. However, the mature short-wave infrared camera such as InGaAs has the disadvantage of complexly heterogeneous integration with complementary metal-oxide-semiconductor (CMOS) readout circuits, leading to high cost and low imaging resolution. Herein, we report a low-cost, high-performance, and high-stability Tex Se1- x short-wave infrared photodiode detector. The Tex Se1- x thin film is fabricated through CMOS-compatible low-temperature evaporation and post-annealing process, showcasing the potential of direct integration on the readout circuit. The device demonstrates a broad-spectrum response of 300-1600nm, a room-temperature specific detectivity of 1.0 × 1010 Jones, a -3dB bandwidth up to 116kHz, and a linear dynamic range of over 55dB, achieving the fastest response among Te-based photodiode devices and a dark current density 7 orders of magnitude smaller than Te-based photoconductive and field-effect transistor devices. With a simple Si3 N4 packaging, the detector shows high electric stability and thermal stability, meeting the requirements for vehicular applications. Based on the optimized Tex Se1- x photodiode detector, we demonstrate the applications in material identification and masking imaging. Our work paves a new way for CMOS-compatible infrared imaging chips. This article is protected by copyright. All rights reserved.

Dual‐band Ganesha‐shaped semi‐transparent antenna for vehicular applications

AbstractIn this paper, work on a Ganesha‐shaped semi‐transparent patch antenna is presented for its use in vehicular application. The design of the antenna is opted from a commercially available Ganesha sticker that is mostly placed on the vehicle's window panes as a symbol of an auspicious deity. The geometry of the sticker without any variation in its dimension is made to work as an antenna. The antenna is fabricated using adhesive copper tape on a glass slab backed by an AgHT‐8 transparent conducting sheet which acts as the ground plane. Microstrip inset feeding technique is used to excite the patch and its return loss performance and free space radiation pattern measurements are carried out. Measured results show promising performances that can be used in future vehicular applications and are in good comparison with that of the simulated results.

A comparative study of single and dual ejector concepts for anodic recirculation system in high-performance vehicular proton exchange membrane fuel cells

The fuel supply system is a critical element in Proton Exchange Membrane Fuel Cell (PEMFC). In vehicular applications, an anode recirculation system (ARS) is required to return residual hydrogen to the fuel line. A 1D model of an ejector-based ARS was created and integrated with a vehicular PEMFC in this study. Therefore, two configurations, single-ejector-based and dual-ejector-based ARS, were developed to regulate the fuel supply and, thus, utilized to examine and conduct a comparative study of their advantages and disadvantages to the dynamic behavior of the stack. The use of ARS was found to improve stack performance and fuel utilization by delivering high stoichiometry, recirculation rate, and relative humidity. Contrary to a single-ejector-based ARS, whose use is restricted due to its limited working range, dual-ejectors can cover all fuel cell stack operating ranges. Sensitivity analysis revealed that primary pressure was the most significant parameter affecting ejector performance and flow characteristics.

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 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.

Analysis of fluctuations of antenna pattern in U-V2X communications

The third-generation partnership project (3GPP) defined several scenarios of vehicle-to-everything (V2X) networks such as vehicle-to-vehicle, vehicle-to-pedestrian, and vehicle-to-infrastructure. Unmanned aerial vehicles (UAVs) exploiting such scenarios for vehicular applications like vehicular-platooning, autonomous driving, and traffic management have shown improved networks’ performance in UAV-V2X (U-V2X) communications. This promising performance is typically obtained by considering high directional UAV antennas. However, the UAV vibration makes UAV antennas’ beam-width sensitive to UAV fluctuations which results in degrading the networks’ performance. Thus, in this paper, the performance of a U-V2X network in the presence of UAV fluctuations is investigated. The UAVs are modeled using an independent homogeneous Poisson Point Process and the vehicular-nodes are modeled using an independent Poisson Line Process. To this end, the association probability and success probability of various links such as vehicular-node connected to a UAV link, vehicular-node connected to a near-by vehicular-node link, and the overall U-V2X link are derived. In addition, the effect of different network settings such as the number of vehicular-nodes, UAVs, roads, and antennas is quantified. Moreover, the spectral efficiency of a U-V2X network is evaluated. Extensive simulations revealed that V2X networks facilitate UAVs and that for less dense areas with fewer roads, buildings, and crowds; UAVs provide more reliable links for connectivity than vehicular-nodes. Furthermore, it is also revealed that UAVs provide less reliable connection for V2X networks with larger UAV antenna fluctuations.

Line-of-sight and non-line-of-sight vehicle-to-vehicle communication using light fidelity

Subject of study. Light fidelity is an alluring complementary communication technology for vehicular applications such as vehicle-to-vehicle and navigation systems. The street light communication system can be utilized for sending data like location, sign boards, traffic ahead, emergencies, speed limit, etc. This can help in easy navigation and reduce traffic congestion. Method. In this paper, a hardware model for vehicle-to-vehicle bidirectional communication along with street-light-to-vehicle communication has been presented. A taillight red color light emitting diode with a headlight white color light emitting diode was employed in the experiment to analyze the range in different situations. Main results. This paper also consists of the simulation of a non-line-of-sight communication channel considering different atmospheric conditions. This is effective in cases where line-of-sight communication is not possible. It has been observed that the Q-factors of the signals were 29.53 and 25.80 in the cases of climatic conditions such as clear and heavy fog, respectively. Practical significance. The transmission distance can be increased using brighter lights like used in real life headlights of cars and better photodiodes with higher photosensitivity and fast response time. The proposed prototype is useful in the case of traffic jams and other traffic scenarios.