Dongyao Jia

A Survey on Platoon-Based Vehicular Cyber-Physical Systems

Vehicles on the road with some common interests can cooperatively form a platoon-based driving pattern, in which a vehicle follows another vehicle and maintains a small and nearly constant distance to the preceding vehicle. It has been proved that, compared with driving individually, such a platoon-based driving pattern can significantly improve road capacity and energy efficiency. Moreover, with the emerging vehicular ad hoc network (VANET), the performance of a platoon in terms of road capacity, safety, energy efficiency, etc., can be further improved. On the other hand, the physical dynamics of vehicles inside the platoon can also affect the performance of a VANET. Such a complex system can be considered a platoon-based vehicular cyber-physical system (VCPS), which has attracted significant attention recently. In this paper, we present a comprehensive survey on a platoon-based VCPS. We first review the related work of a platoon-based VCPS. We then introduce two elementary techniques involved in a platoon-based VCPS, i.e., the vehicular networking architecture and standards, and traffic dynamics, respectively. We further discuss the fundamental issues in a platoon-based VCPS, including vehicle platooning/clustering, cooperative adaptive cruise control, platoon-based vehicular communications, etc., all of which are characterized by the tightly coupled relationship between traffic dynamics and VANET behaviors. Since system verification is critical to VCPS development, we also give an overview of VCPS simulation tools. Finally, we share our view on some open issues that may lead to new research directions.

A Disturbance-Adaptive Design for VANET-Enabled Vehicle Platoon

In highway systems, grouping vehicles into platoons can improve road capacity and energy efficiency. With the advance of technologies, the performance of platoons can be further enhanced by vehicular ad hoc networks (VANETs). In the past few years, many studies have been conducted on the dynamics of a VANET-enabled platoon under traffic disturbance, which is a common scenario on a highway. However, most of them do not consider the impact of platoon dynamics on the behaviors of VANETs. Moreover, most existing studies focus on how to maintain the stability of a platoon and do not address how to mitigate negative effects of traffic disturbance, such as uncomfortable passenger experience, increased fuel consumption, and increased exhaust emission. In this paper, we will investigate the dynamics of the VANET-enabled platoon from an integrated perspective. In particular, we first propose a novel disturbance-adaptive platoon (DA-Platoon) architecture, in which a platoon controller shall adapt to the disturbance scenario and shall consider both VANET and platoon dynamics requirements. Based on a specific realization of the DA-Platoon architecture, we then analyze the traffic dynamics inside a platoon and derive desired parameters, including intraplatoon spacing and platoon size, so as to satisfy VANET constraints under traffic disturbance. To mitigate the adverse effects of traffic disturbance, we also design a novel driving strategy for the leading vehicle of a platoon, with which we can determine the desired interplatoon spacing. Finally, we conduct extensive simulation experiments, which not only validate our analysis but also demonstrate the effectiveness of the proposed driving strategy.

Cloud-Assisted Safety Message Dissemination in VANET–Cellular Heterogeneous Wireless Network

In vehicular ad hoc networks (VANETs), efficient message dissemination is critical to road safety and traffic efficiency. Since many VANET-based schemes suffer from high transmission delay and data redundancy, the integrated VANET–cellular heterogeneous network has been proposed recently and attracted significant attention. However, most existing studies focus on selecting suitable gateways to deliver safety message from the source vehicle to a remote server, whereas rapid safety message dissemination from the remote server to a targeted area has not been well studied. In this paper, we propose a framework for rapid message dissemination that combines the advantages of diverse communication and cloud computing technologies. Specifically, we propose a novel Cloud-assisted Message Downlink dissemination Scheme (CMDS), with which the safety messages in the cloud server are first delivered to the suitable mobile gateways on relevant roads with the help of cloud computing (where gateways are buses with both cellular and VANET interfaces), and then being disseminated among neighboring vehicles via vehicle-to-vehicle (V2V) communication. To evaluate the proposed scheme, we mathematically analyze its performance and conduct extensive simulation experiments. Numerical results confirm the efficiency of CMDS in various urban scenarios.

High-Efficiency Urban Traffic Management in Context-Aware Computing and 5G Communication

With the increasing number of vehicle and traffic jams, urban traffic management is becoming a serious issue. In this article, we propose novel four-tier architecture for urban traffic management with the convergence of VANETs, 5G networks, software-defined networks, and mobile edge computing technologies. The proposed architecture provides better communication and more rapid responsive speed in a more distributed and dynamic manner. The practical case of rapid accident rescue can significantly shorten the rescue time. Key technologies with respect to vehicle localization, data pre-fetching, traffic lights control, and traffic prediction are also discussed. Obviously, the novel architecture shows noteworthy potential for alleviating traffic congestion and improving the efficiency of urban traffic management.

Multi anticipative bidirectional macroscopic traffic model considering cooperative driving strategy

ABSTRACT Recent development of information and communication technologies (ICT) has enabled vehicles to timely communicate with others through wireless technologies, which will form future (intelligent) traffic systems (ITS) consisting of so-called connected vehicles. Cooperative driving with the connected vehicles is regarded as a promising driving pattern to significantly improve transportation efficiency and traffic safety. In the vast literature of traffic flow theory, there are continuum models considering multiple forward anticipative strategy, where the driver reacts to many leaders. Few study effort has been undertaken to include bidirectional driving strategy, where the driver reacts to both direct leader and direct follower, in the continuum traffic flow models. This paper aims to derive a continuum traffic model considering both multiple forward and backward driving strategy. It is shown that the derived model is a generalised version of a current continuum model for ITS and can improve important properties of such bidirectional (continuum) model.

Improving the Uplink Performance of Drive-Thru Internet via Platoon-Based Cooperative Retransmission

For many vehicular safety applications, it is critical to timely and reliably deliver multimedia data from a traveling vehicle to a roadside access point (AP) in an error-prone vehicular ad hoc network (VANET), which is a typical uplink scenario for drive-thru Internet. To achieve this goal, we propose a cooperative retransmission scheme that exploits a common phenomenon in reality, in which consecutive vehicles can naturally form a platoon to reduce energy consumption. We develop a 4-D Markov chain to model the proposed scheme and analyze the uplink throughput of drive-thru Internet, which also reveals some fundamental relationships among traffic flow, platoon parameters, and system throughput. We conduct extensive simulation in OMNeT++ to validate our scheme and the analytical model. Numerical results show that the proposed platoon-based cooperative retransmission scheme significantly improves the uplink throughput of drive-thru Internet, considerably decreases the total transmission times for a given quantity of upload data, and, hence, achieves a greener mobile multimedia communication.

A multiclass microscopic model for heterogeneous platoon with vehicle-to-vehicle communication

ABSTRACT Connected and autonomous (CA) vehicles have been verified to significantly improve traffic efficiency. However, there is still a long lifespan for heterogeneous traffic flow consisting of both human-driven and CA vehicles. Thus a deep understanding of the heterogeneous platoon dynamics is critical to the traffic stability issues for the deployment of CA vehicles in the near future. This paper aims to develop a multiclass microscopic model for a heterogeneous platoon which can explicitly demonstrate the interaction between human-driven and CA vehicles. Specifically, the consensus-based control algorithm is adopted to model the dynamics of CA vehicles and a typical car-following model is used to describe the dynamics of human-driven vehicles. We then theoretically and numerically study the linear stability condition of the heterogeneous platoon which takes into account the probabilistic delay in the communication, the penetration of the CA vehicles, and the relative order of the vehicle types in the platoon.

Improving beacon dissemination in VANETs — A cyber-physical system based design

One critical issue for vehicular safety applications is how to timely and reliably disseminate kinetic information, known as beacon, among vehicles. In this paper, we try to improve the beacon dissemination performance in vehicular ad hoc networks (VANETs) especially in drastic disturbance scenarios. To this end, a decentralized beacon dissemination control scheme (DBDCS) is proposed from the cyber-physical system perspective, where both the vehicle dynamics and VANET behaviors are jointly considered. In the envisioned scheme, the control channel interval for beacon dissemination can be adaptively adjusted based on both the current local traffic dynamics and the networking situation. Numerical results show that the proposed scheme can significantly improve the beacon dissemination performance especially in disturbance scenarios.

A Joint Control–Communication Design for Reliable Vehicle Platooning in Hybrid Traffic

Recent studies have shown that traffic safety and efficiency can be substantially improved by vehicle platooning, in which vehicles periodically broadcast their kinetic status to neighbors, known as beacon message dissemination. As a networked control system, vehicle platoon has attracted significant attention from both the control and networking areas. However, few studies consider the practical traffic scenario with both platoons and individual vehicles, and the proposed beaconing schemes lack the deep understanding of relationship between the beaconing performance and the requirements of the control mechanism. To address these challenging issues, we propose a joint control–communication design to achieve reliable vehicle platooning in a more realistic traffic scenario, wherein the traffic consists of both platoons and individual vehicles, and both periodic beacon messages and event-based safety messages shall be delivered together. Specifically, we first develop a comprehensive control-theoretical analysis to understand how the vehicular communication can affect features of platoon driving; based on the understanding, we then propose and analyze an adaptive platoon-based message dissemination scheme; finally, we conduct extensive numerical experiments to validate the effectiveness of the protocol and to confirm the accuracy of the our theoretical analysis.

Infrastructure-Assisted Message Dissemination for Supporting Heterogeneous Driving Patterns

With the advances of Internet of Things technologies, individual vehicles can now exchange information to improve traffic safety, and some vehicles can further improve safety and efficiency by coordinating their mobility via cooperative driving. To facilitate these applications, many studies have been focused on the design of inter-vehicle message dissemination protocols. However, most existing designs either assume individual driving pattern or consider cooperative driving only. Moreover, few of them fully exploit infrastructures, such as cameras, sensors, and road-side units. In this paper, we address the design of message dissemination that supports heterogeneous driving patterns. Specifically, we first propose an infrastructure-assisted message dissemination framework that can utilize the capability of infrastructures. We then present a novel beacon scheduling algorithm that aims at guaranteeing the timely and reliable delivery of both periodic beacon messages for cooperative driving and event-triggered safety messages for individual driving. To evaluate the performance of the protocol, we develop both theoretical analysis and simulation experiments. Extensive numerical results confirm the effectiveness of the proposed protocol.