Research on Reliable and Efficient Message Dissemination in Cooperative Driving Systems

Abstract

A group of vehicles with common interests can drive in a cooperative manner, namely cooperative driving, which can further improve transportation efficiency and traffic safety. A typical application is the vehicle platooning, in which a vehicle can obtain the timely kinetic information of multiple preceding vehicles with inter-vehicle communication links, and then adopt a suitable control. To support the cooperative driving pattern, vehicles in the same group shall periodically sense their kinetic status (e.g. speed, position, acceleration) and broadcast such information to other vehicles in the same group, and then each vehicle can adopt a suitable control law to achieve a certain objective, such as maintaining a constant inter-vehicle spacing. In the past few years, cooperative driving has attracted significant attention from both academia and industry. For example, the E.U.-sponsored SARTRE program recently demonstrated a platoon that consists of vehicles moving at speeds up to 90 km/h with a gap between consecutive vehicles of no more than 6m.

In this dissertation, some fundamental issues in message dissemination for cooperative driving systems are investigated. These issues include: a consensus-based vehicle control mechanism for supporting vehicle communication, a joint control-communication design for cooperative driving, an infrastructure-assisted message dissemination for supporting heterogeneous driving pattern, and cloud-assisted safety message dissemination in VANET-cellular heterogeneous wireless network.

Clearly, for an efficient cooperative driving system, it is necessary to design not only the advanced control mechanism for vehicles in the same cooperative driving systems, but also the efficient inter-vehicle communication (IVC) protocol to deliver control messages. However, most existing studies consider the two areas separately. For instance, for the platoon control, a few work fully considered the realistic IVC implementation. On the other hand, most existing communication protocols were designed without in-depth understanding on whether the beaconing performance can meet the requirements of platoon control. In this study, we systematically investigate how to support reliable vehicle platooning in the hybrid traffic scenario by a joint control-communication design. Specifically, we propose the coupled design which combines the consensus-based control theory and adaptive communication protocols. To the best of our knowledge, this is a first attempt that vehicle platooning is integrally designed from both communication and control perspective, which deeply explores the interplay between them.

The advances of Internet of Thing (IoT) have greatly promoted the development of intelligent transport systems (ITS). Specifically, by the aid of the advanced sensing, vehicular communication and computing technologies, an individual vehicle can quickly detect traffic anomalies and then notify neighboring vehicles so as to improve traffic safety. most existing studies design distributed communication schemes among vehicles, which cannot fully utilize the advanced capability of infrastructure, such as sensors/cameras deployed along the road, and road side units (RSUs) for communications. In this study, we systematically investigate how to support reliable message dissemination in a hybrid traffic scenario by fully utilizing the context awareness of roadside sensors as well as the vehicle-to-infrastructure (V2I) communication that combines both centralized and distributed approaches. 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.

Although these VANET-based schemes are viable, it is still challenging to timely and reliably disseminate messages to a targeted area under the inherently intermittent vehicular networking environment, due to the limited transmission range of DSRC as well as the contention-based carrier-sense multiple access with collision avoidance (CSMA/CA) scheme in IEEE 802.11p protocol. For long-distance dissemination of safety messages, a better solution is the cellular network. A cloud-assisted VANET can acquire instantaneous traffic flows, have macro control of the geographical position of all vehicles, make an accurate assessment of the cause of the congestion and traffic flow, and determine the targeted area and desired recipients. Therefore, it can send the safety message to vehicles distributed in different areas. In this study, we propose a cloud-assisted safety message dissemination framework for an integrated system that consists of both cloud infrastructure and VANET–cellular heterogeneous wireless networks. Specifically, we consider an integrated VANET–cellular network, where the buses act as mobile gateways. Cloud servers, on the other hand, can acquire instantaneous traffic flow data and the geographical position of all mobile gateways and hence efficiently deliver important traffic information (traffic accident, route recommendation, etc.) to the vehicles in the targeted area.

Date of Award	11 Jan 2018
Original language	English
Awarding Institution	City University of Hong Kong
Supervisor	Jianping WANG (Supervisor) & Libing Wu (External Supervisor)