Vehicular communication–a technical overview

Research efforts carried out on Intelligent Transportation Systems (ITS) for improving safety and efficiency of road transportation have been focused on cars, where vehicular communications have demonstrated to enhance the driver awareness with active services that improve fatality statistics. Although common vehicles accidents have been reduced in the last years, those involving vulnerable road users remain. Cyclists and motorcyclists cover a whole area where ITS and telematics should be embedded with no doubt, given the incremental popularity of bikes and motorbikes in urban mobility and short interurban routes. For this reason, this work takes the key objective of integrating two-wheelers within the future cooperative ITS network. Hence, a novel communication device especially adapted to cyclists and motorcyclists has been designed, by integrating vehicular wireless communications (i.e. IEEE 802.11p) and considering interface limitations. From the protocols perspective the work is focused on IPv6, and considers two-wheelers as part of the Future Internet. In fact, a great success of the proposal is exploiting the synergy between IETF (Internet) and ITS-specific protocols coming from ISO and ETSI, creating a novel active system to improve two-wheel transport safety through Cooperative Awareness Messaging (CAM) over IPv6. The embedded communication node for two-wheelers includes the proper software to warn the driver about the approaching of a regular vehicle through audio and visual notifications. Moreover, its counterpart for common cars has also been developed, but using an Android application running on a handheld device connected to a regular IPv6 in-vehicle network.

Recently, the Third Generation Partnership Project (3GPP) introduced new radio (NR) technology for vehicle-to-everything (V2X) communication to enable delay-sensitive and bandwidth-hungry applications in vehicular communication. The NR system is strategically crafted to complement the existing long-term evolution (LTE) cellular-vehicle-to-everything (C-V2X) infrastructure, particularly to support advanced services such as the operation of automated vehicles. It is widely anticipated that the fifth-generation (5G) NR system will surpass LTE C-V2X in terms of achieving superior performance in scenarios characterized by high throughput, low latency, and enhanced reliability, especially in the context of congested traffic conditions and a diverse range of vehicular applications. This article will provide a comprehensive literature review on vehicular communications from dedicated short-range communication (DSRC) to NR V2X. Subsequently, it delves into a detailed examination of the challenges and opportunities inherent in NR V2X technology. Finally, we proceed to elucidate the process of creating and analyzing an open-source 5G NR V2X module in network simulation-3 (ns-3) and then demonstrate the NR V2X performance in terms of different key performance indicators implemented through diverse operational scenarios.

Connected vehicle technology provides many potential benefits on the road such as safety applications, effective traffic management, and mobile Internet access. In order to mitigate the resulting high spectrum demands and provide vehicular connectivity with wider communication range, higher transmission rate, and lower data transfer cost, in this article, we exploit the abundant TV white space with superior propagation characteristics and building penetration performance. We first present the application scenarios exploiting TV white space in heterogeneous connected vehicular communication networks, and discuss white space channel availability and characteristics for vehicular communications. We then propose TV white space geolocation database based vehicular communication architectures for vehicle-to-infrastructure (V2I) communications and vehicle-to-vehicle (V2V) communications. Finally, we highlight the key technical challenges and pinpoint future research directions toward exploiting TV white space for vehicular communication networks.

The rapid development of the Intelligent Transportation System increases the potential of Vehicular communication in a smart transportation network. Although there are several technological attempts to support vehicular communication, they have limitations from various perspectives including mobility, security, resource allocation, and device-to-device communication. In order to address those limitations, this study evaluates the most appropriate communication technology to transmit data in the future Vehicle to Everything (V2X) communication system. First, we conduct a performance evaluation of the current main vehicular communication system requirements. Then, we analyze the applications of communication technologies such as wi-fi, LTE, 5G, and 6G to fulfill the requirements of future V2X communication. Later, we explore the advanced features of 6G in the context of the Intelligent Transportation System. Then, we suggest that 6G technology as the corresponding communication technology to future V2X communication systems based on the analysis. Finally, we propose an architecture for the 6G V2X network and discuss security challenges and suggested solutions for the architecture.

ABSTRACTInformation and communication technologies are being massively applied in the automotive field as the basis of the new generation of active safety systems. In this extensive field of technologies, vehicular communications will constitute the core of a large set of advanced driving assistance systems for improving road safety as well as helping to reduce the environmental impact of transport. These communication technologies are currently under deployment, but their mandatory installation in newly manufactured cars is foreseen in the next 5 years. This equipment will enable the new Advanced Driver Assistance Systems (ADAS) system to be installed in these vehicles. Many of these safety applications are currently under development. However, there are some road users who are not commonly included in this vehicular communication ecosystem, specifically, vulnerable road users, such as pedestrians, cyclists, and motorcyclists. Current assistance systems focused on reducing crashes with this user group are based on sensors installed in the vehicles but do not include vehicular communications. In this article, we present a novel Vulnerable Road User (VRU) warning system based on Vehicle-to-Vehicle (V2V) communications, which is capable of detecting a motorcycle circulating in the vicinity of the connected vehicles, launching sound and visual warnings, and using a smartphone as human-machine interface. The system has been designed, implemented, and tested in the laboratory as well as on real roads in real traffic flow.

Vehicular communications is an important enabler for enhancing the safety on roads by supporting mutual awareness of vehicles as well as for improving the efficiency of transportation through smart traffic management by intelligent transport systems (ITSs). Governments around the world have set ambitious goals for road fatality reduction in the near future; e.g., the European Union targets a 50% reduction of road fatalities by 2020 as compared to the year 2010. Furthermore, traffic telematic systems aim to minimize the environmental impact of transportation and maximize the utilization of available road infrastructure by adaptive traffic management. To realize these challenging targets, autonomous wireless information exchange among vehicles-vehicle to vehicle (V2V)-and with roadside infrastructure-vehicle to infrastructure (V2I)-are central ingredients. In addition to traffic efficiency and safetyrelated issues, vehicular communications is increasingly recognized as an important revenue driver by car manufacturing companies since it enables wirelessly connected in-vehicle entertainment systems that support on-demand video streaming and online Internet access for passengers. Also, in the future, machine-type communication is expected to play a major role in vehicular environments, with more sensors that monitor the internal state of vehicles and autonomously exchange service and maintenance information with cloud servers of manufacturers. Depending on the considered use-case, distinct quality of service (QoS) requirements come into play [1]: infotainment applications for in-car users require high bandwidth and network capacity, active road safety relies on delay- and outage-critical data transmission, whereas information exchange for road traffic efficiency management typically comes without strict QoS requirements and exhibits graceful degradation of performance with increasing latency.

Part 1: Fuel and Feed the World 1. Global Energy Production, Consumption and Potentials of Biomass 2. Bioenergy Crops versus Food Crops 3. Transportation Biofuels 4. Primary Biomass Productivity, Current Yield Potentials, Water and Land Availability 5. Harvesting, Logistic and Delivery of Biomass 6. Technical Overview: Feedstocks, Types of Biofuels and Conversion Technologies 7. Environmental Impact 8. Economic and Social Dimensions 9. Integrated Bionergy Farms and Rural Settlements Part 2: Energy Crops Guide 10. Energy Crops Guide Part 3 11. Ethanol Crops 12. Oil Crops 13. Biogas from Crops 14. Hydrogen and Methanol Crops 15. Underutilized and Unexploited Crops. Appendices

Vehicular communication platforms that provide real-time access to wireless networks have drawn more and more attention in recent years. IEEE 802.11p is the main radio access technology that supports communication for high mobility terminals, however, due to its limited coverage, IEEE 802.11p is usually deployed by coupling with cellular networks to achieve seamless mobility. In a heterogeneous cellular/802.11p network, vehicular communication is characterized by its short time span in association with a wireless local area network (WLAN). Moreover, for the media access control (MAC) scheme used for WLAN, the network throughput dramatically decreases with increasing user quantity. In response to these compelling problems, we propose a reinforcement sensor (RFS) embedded vertical handoff control strategy to support mobility management. The RFS has online learning capability and can provide optimal handoff decisions in an adaptive fashion without prior knowledge. The algorithm integrates considerations including vehicular mobility, traffic load, handoff latency, and network status. Simulation results verify that the proposed algorithm can adaptively adjust the handoff strategy, allowing users to stay connected to the best network. Furthermore, the algorithm can ensure that RSUs are adequate, thereby guaranteeing a high quality user experience.

Recently, electric vehicles (EVs) have been introduced as an alternative method of transportation to help mitigate environmental issues, such as carbon emissions and fuel consumption, caused by conventional transportation systems. The implementation of effective EV charging systems is essential to motivate mass adoption of EVs. Accordingly, fast and reliable communications between the charging systems and the EVs are vital for efficient management of the charging process. Different radio access technologies (RATs) are discussed in the literature to enable communication between the highly mobile EVs and the charging subsystems, to collect and exchange information such as state of charge (SoC), users’ locations, and charging decisions between the different network entities. This information can be used to coordinate charging plans and select the optimal routes for moving vehicles. This paper presents a survey of existing literature on vehicular communications for EV charging coordination and management. The communication requirements and feasible communication technologies for vehicular communication are first discussed in details. A review of the physical layer security strategies is then presented and the role of the different RATs in EV charging coordination and management is described and studied.

Always best connected (ABC) communication is an essential requirement for intelligent transportation system. In this paper, we propose a cognitive vertical handover (CVHO) engine to ensure seamless connectivity on the move. Analytic hierarchy process and artificial neural network are used for the development of the algorithm and MATLAB is used as simulation platform. The CVHO engine, which is knowledge based context aware system, takes into account multiple relevant criteria and previous experiences. This system is capable of performing both voluntary and reflex actions. A detailed literature review is presented to compare this work with the conventional methods of vertical handover. A case study, considering the network selection in a typical highway traffic scenario, which consists of both peer-to-peer (P2P) and mobile networks, is presented for the validation of the design. Three radio access technologies, WLAN (P2P), UMTS and WiMAX (mobile networks), are considered for simulation. The results show that the presented model not only realistically optimizes the best available network on the move but also avoids unnecessary handovers. This algorithm is specific to vehicular communication system and hence variation in network selection with vehicle speed is shown.

A polarization-selective and reconfigurable Fresnel zone plate consisting of frequency selective surfaces (FSS) loaded with varactor diodes is devised for compact vehicular wireless communication devices. The unit cell constituting the impedance zone exhibits rapid impedance transitions from 0 ohm (electrically-opaque) to 377 ohm (electrically-transparent). An I-shape configuration is employed for the resonant unit cell structure, featuring high compatibility with DC bias voltage network. In addition, double-sided FSS is employed on the top and bottom faces for polarization-selective beamforming. The FSS comprise of a dielectric with near zero thickness ( λ /250 of 2.40 GHz) resulting in intentionally high mutual coupling between the layers. The devised unit cell is designed using an equivalent circuit model analysis and optimized using finite element solver, achieving over 30 dB impedance switching. The proposed unit cell is experimentally confirmed in both vertical and horizontal polarizations. By configuring the DC voltage bias lines, the unit cells of the FSS are transformed into electrically-driven impedance zones formulating alternating and repetitive gratings. The width and the interval of the grating manipulate the constructive and destructive interference resulting in beam scanning range of 30° in both vertical and horizontal polarizations. The proposed approach can provide concise and compact beamforming solutions for future vehicular communications.

In millimeter wave (mmWave) vehicular communications, multi-hop relay disconnection by line-of-sight (LOS) blockage is a critical problem, especially in the early diffusion phase of mmWave-available vehicles, where not all the vehicles have mmWave communication devices. This paper proposes a distributed position control method for autonomous vehicles to make long relays connecting to road side units (RSUs) by avoiding blockages to communicate with each other via LOS paths. Even though vehicles with the proposed method do not use the whole information of the environments and cooperate with each other, they can decide their action (e.g., lane change and overtaking) to form long relays using only information of its surroundings (e.g., surrounding vehicle positions). The decision-making problem is formulated as a Markov decision process so that autonomous vehicles can learn a practical movement strategy of making long relays by a reinforcement learning (RL) algorithm. This paper designs a learning algorithm based on a sophisticated deep reinforcement learning algorithm, asynchronous advantage actor-critic (A3C), which enables vehicles to learn a complex movement strategy quickly by its deepneural-network architecture and multi-agent-learning mechanism. Once the strategy is well trained, vehicles can distributedly move to positions where the long relay to the RSU is established. Simulations results confirm that the proposed method can increase the relay length and coverage even if the traffic conditions and penetration ratio of mmWave communication devices in learning and operation phases are different.

Automotive industry will be greatly benefited by the advent of 5G Networking and the huge boost in performance and coverage it will support. Road safety and traffic efficiency services will be significantly upgraded through seamlessly interconnected devices, while latency decrease will most likely allow autonomous driving to become a commodity, available to everyone. This technology will have a huge societal and economical impact, since it will render severe traffic accidents, long commute times and increased energy consumption obsolete. Current vehicular communication systems are usually equipped with orthogonal frequency division multiplexing (OFDM) transceivers that operate in suboptimal modes for the upcoming 5G standards. The problem originates in the existing intercarrier interference (ICI) on the receiver end, often partially tackled by integrated successive interference cancellation (OSIC) architectures. However, for decreasing complexity, system designers attempt to mitigate ICI by considering only a small number or sub-carriers, leading to error floor introduction and unacceptable bit-error-rates (BER). This paper presents an OSIC-based solution for cancelling interference in OFDM systems operating over specific conditions such as doubly selective channels. The experimental results indicated that the proposed equalizer outperforms all existing non-banded ICI cancellation methods, by achieving lower BER despite operating in a resource-savvy manner.

Edge based authentication protocol for vehicular communications without trusted party communication

Millimeter-wave communications have been recently proposed as a promising candidate to fulfill the connectivity requisites imposed over autonomous driving. The need for transmission capabilities of multiple gigabits per second for autonomous vehicles is the main driving factor for millimeter-wave technology. However, there are other paramount requirements, such as short delays, high reliability, security, and support for both unicast and broadcast communications, which must be carefully addressed before this technology becomes a reality. In this article we first review the state-of-the art modeling frameworks that are being considered for vehicular communications. Then we explore the key technologies that will enhance the suitability of millimeter-wave communications for autonomous driving, and we investigate the main challenges that need to be overcome. Finally, we envision that a combination of analog/ hybrid beamforming with a location-based beam search protocol, using full duplex radio and physical layer key generation, has the potential of fulfilling the requirements of autonomous driving technology.