VANET中基于RSU辅助签名环形成的方案

车辆自组织网络(Vehicular Ad-hoc Network,VANET)使交通系统更加智能和高效。信道的开放性以及车辆移动的高速性等特点,导致VANET存在诸如身份、传输数据以及位置等隐私信息泄露问题。目前,针对VANET的身份隐私泄露问题,越来越多的学者采用基于环签名的方案,但是车辆如何在行驶过程中与周围车辆组成签名环一直是一个难解决的问题。针对基础设施部署较完善地区,文中提出一种基于RSU(Road-Side Unit)辅助签名环形成的方案。该方案通过RSU收集覆盖区域内车辆的公钥并广播公钥集,从而确定区域内车辆的签名环,并利用双线性对映射实现RSU与车辆间消息传输的基于身份加密的过程。安全分析和实验证明,所提方案在基础设施较完善地区能够拥有较好的效率和安全性。     

基于无证书代理重签名的车载自组网消息认证方案

基于代理重签名和无证书公钥密码体制,提出了一个安全的车载自组网消息认证方案。认证中心利用代理重签名技术,可转换车载单元对消息的签名为路边单元的签名,从而降低了根据签名识别车辆身份的风险,实现通信消息的匿名性。采用无证书公钥密码体制将各实体的私钥分为两部分,有效解决了车载自组网中的证书管理与密钥托管问题。如果车辆发布虚假消息,认证中心能准确追溯到车辆的真实身份,并召回违法车辆。与Huang方案相比,新方案具有较高的安全性和较低的通信开销。     

Restricted usage of anonymous credentials in vehicular ad hoc networks for misbehavior detection

The automobile industry is entering a new era of digitalization with major impact on human mobility and transportation infrastructures. A result of such a convergence between the automobile and information technologies is vehicular ad hoc network (VANET), a type of mobile ad hoc networks that has recently enjoyed a lot of attention from the industry, the research community, lawmakers and privacy activists. In VANET, vehicles frequently broadcast various types of messages, including location data. This enables innovative applications and improvements in safety and driving experience. As messages broadcasted in the VANET are digitally signed and the receiver must be able to verify the sender’s authentication and message integrity, there is a need to ensure broadcast authentication and protect driver’s anonymity. However, communication in VANETs takes place with high frequency, and malicious vehicles can hide behind anonymity in order to duplicate packets and get advantage over other vehicles in the network. Indeed, state-of-the-art approaches to privacy-preserving messages broadcast in the VANET typically ensure that each vehicle has a number of pseudonymous certificates that are changed regularly in order to thwart an automated tracing of its activities. However, the possibility of uncontrolled simultaneous use of pseudonyms by misbehaving vehicles remain unaddressed. This paper proposes a set of anonymous credential system based protocols for VANET that enables the detection and limitation of pseudonym/credential overspending. The revocation of the misbehaving vehicle can be also achieved through the proposed solutions. With the prototypical implementation of the proposed protocols, it has been shown that the successful detection of fraud, i.e., pseudonyms overspending and the subsequent revocation of credentials are possible in VANET.     

车联网的多跳广播协议及移动模型仿真的研究现状

由于车联网(VANET,vehicular Ad Hoc networks)的节点移动速度快、拓扑动态变化以及移动轨迹局限性等特性,多跳广播成为VANET中车间通信的有效方式之一.此外,由于直接在真实环境中评估VANET的性能是非常困难的,仿真成为研究VANET的有效工具.为此,先分析VANET的网络结构,再讨论了广播协议的发展现状,并分析了典型的广播协议.随后论述了VANET移动模型仿真的发展现状,并重点分析、对比了当前交通仿真器和网络仿真器的特点.最后,探讨了车载自组网仿真器未来的发展方向.     

车联网RSU单元下行流量的性能研究

基于802.11p/WAVE的车联网是一项涉及道路交通、无线通信、自组织系统等多学科综合性的技术领域,车联网中,RSU单元可作为AP,让在行驶的汽车中的人们可以随时随地接入Internet,其中,如何建立RSU单元的下行流量模型是一个关键问题.通过引入车辆密度概率质量函数,分析车联网MAC层车辆通过RSU设备访问Internet的信道竞争情形,提出了适用于高速公路交通场景的RSU单元网络吞吐量模型,并推导出RSU上行及下行流量的性能解析式.针对RSU单元通信范围有限、相邻RSU单元之间可能存在盲区的问题,提出了一种利用同向行驶的车辆协助数据下载的VCoDS方案,以达到提高某时间段RSU的下行流量的目标.仿真实验结果证实,VCoDS方案可有效提高RSU单元的下行流量.     

LESPP: lightweight and efficient strong privacy preserving authentication scheme for secure VANET communication

Authentication in vehicular ad-hoc network (VANET) is still a research challenge, as it requires not only secure and efficient authentication, but also privacy preservation. In this paper, we proposed a lightweight and efficient authentication scheme (LESPP) with strong privacy preservation for secure VANET communication. The proposed scheme utilizes self-generated pseudo identity to guarantee both privacy preservation and conditional traceability, and it only requires a lightweight symmetric encryption and message authentication code (MAC) generation for message signing and a fast MAC re-generation for verification. Compared with currently existing public key based schemes, the proposed scheme significantly reduces computation cost by \(10^2\)–\(10^3\) times and decreases communication overhead by 41.33–77.60 %, thus achieving resilience to denial of service (DoS) attack. In LESPP, only key management center can expose a vehicle’s real identity from its pseudo identity, therefore, LESPP provides strong privacy preservation so that the adversaries cannot trace any vehicles, even if all roadside units are compromised. Furthermore, vehicles in LESPP need not maintain certificate revocation list (CRL), so any CRL related overhead is avoided. Extensive simulations reveal that the novel scheme is feasible and has an outstanding performance of nearly 0 ms network delay and 0 % packet loss ratio, which are especially appropriate for realtime emergency event reporting applications.     

车牌精确定位与实现

车牌识别系统作为自动识别车辆的一种重要形式,是城市智能交通管理系统中不可或缺的重要组成部分,广泛用于路桥、隧道等卡口的自动收费系统、现代住宅小区、停车场、重要机关单位的汽车出入控制、车流监控等重要场合,尤其在高速公路收费系统中,车牌自动识别更是一个重要的环节。车牌定位作为车牌自动识别中的关键步骤,对系统识别率有重要的影响。     

The effect of communicational signals on drivers' subjective appraisal and visual attention during interactive driving scenarios

Communicational signals (e.g. lights and horns) are imperative for on-road interaction between drivers. The aim of the present study was to explore how these signals affect drivers' subjective appraisal and visual attention, and how drivers decode the signals from other vehicles within a variety of interactive contexts. Twenty-five male participants (20 valid samples, ranging from 21 to 29 years of age) were recruited to watch film clips of pre-designed interactive scenarios involving common vehicle signals in a full-view simulator (i.e. including road view and mirror views). Participants' attitudes towards the interacting vehicle's behaviours, emotional responses, fixation metrics, and decoded meanings were recorded and analysed. The majority of tested signals, with the exception of the horn used in the behind vehicles, significantly improved drivers' attitudes and pleasure. All signals significantly increased emotional arousal, as well as the total fixation time and mean fixation duration on the interacting vehicle. When the interacting vehicle was visible in mirrors, the signal usage significantly increased the fixation frequency towards it. Meanwhile, a significant decrease in total fixation time and mean fixation duration on the road was reported. The results also demonstrated that the decoded signal contained several meanings simultaneously depending on both the signal type and its interactive context. This study quantified the communication process via vehicular signals under typical situations involving other vehicles, and also suggested new ideas on how to establish more advanced communication between drivers.     

Multi-Level Planning for Semi-autonomous Vehicles in Traffic Scenarios Based on Separation Maximization

The planning of semi-autonomous vehicles in traffic scenarios is a relatively new problem that contributes towards the goal of making road travel by vehicles free of human drivers. An algorithm needs to ensure optimal real time planning of multiple vehicles (moving in either direction along a road), in the presence of a complex obstacle network. Unlike other approaches, here we assume that speed lanes are not present and that different lanes do not need to be maintained for inbound and outbound traffic. Our basic hypothesis is to carry forward the planning task to ensure that a sufficient distance is maintained by each vehicle from all other vehicles, obstacles and road boundaries. We present here a 4-layer planning algorithm that consists of road selection (for selecting the individual roads of traversal to reach the goal), pathway selection (a strategy to avoid and/or overtake obstacles, road diversions and other blockages), pathway distribution (to select the position of a vehicle at every instance of time in a pathway), and trajectory generation (for generating a curve, smooth enough, to allow for the maximum possible speed). Cooperation between vehicles is handled separately at the different levels, the aim being to maximize the separation between vehicles. Simulated results exhibit behaviours of smooth, efficient and safe driving of vehicles in multiple scenarios; along with typical vehicle behaviours including following and overtaking.     

车载自组网中可撤销的聚合签名认证方案

为解决车载自组网(VANET)面临的通信安全和隐私保护方面的问题,提出了一种车载自组网中可撤销的聚合签名认证方案.该方案通过匿名认证保障用户隐私,通过使用防篡改设备和聚合签名技术提高认证效率.为实现车辆撤销,要求车辆使用路边单元发放的成员密钥生成签名,当车辆进入路边单元的通信范围时,路边单元实时审查车辆身份,拒绝为撤销...     

Multiple hypothesis tracking for data association in vehicular networks

The introduction of Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communications in Intelligent Transportation Systems of the future brings new opportunities and new challenges into the automotive scene. Vehicular communications broaden the information spectrum that is available to each vehicle, allowing the enhancement of existing applications and the introduction of new ones. Undoubtedly, the impact of this new technology in transportation safety, efficiency and infotainment is expected to be very important.A significant part of research in vehicular networks (VANETs) is dedicated to networking issues like routing and safety. However, perception systems which until now were based on onboard sensors only, need to incorporate the wirelessly received information in order to extend the situation awareness of the vehicle and the driver. This paper presents an algorithm for associating targets tracked from an onboard radar sensor with the position and motion data received from the VANET. The core of the algorithm is a track oriented multiple hypothesis tracker that is modified for incorporating information included in VANET messages. The algorithm is tested in real scenarios using two experimental vehicles and then compared with two other algorithmic approaches. One is using a simpler single hypothesis algorithm for association of VANET messages and the second is using only the onboard sensors for environment perception. As a result, the advantages of the Multiple Hypothesis Algorithm regarding association performance and the added value of wireless information in the perception system are highlighted.     

Real-time vehicle tracking mechanism with license plate recognition from road images

Abstract Information about vehicles on the road is very important for the maintenance of traffic control in current complex traffic condition. Images of vehicles are captured by vehicle-directed cameras. This paper proposes a new vehicle tracking mechanism using license plate recognition technology, which is essential to having information about vehicles on the roads. The proposed method is a real-time processing system using multistep image processing, as well as recognition and tracking processes from 2D and 3D images. The experimental results of real environmental images in recognition and tracking using the proposed method are shown.     

VANET中流调度与路径选择联合优化的传输策略

由于车辆节点与路边设施的强大存储与计算能力、良好的无线通信能力以及不间断的能量供应，车载自组网（vehicular ad-hoc network，简称VANET）可检测车辆行驶环境的变化，评测危险路况并预警，如前方事故现场预警、交叉路口防碰撞预警等，预估司机的反应时间，为安全驾驶及驾驶体验提供技术支持.但VANET中，数据传输面临无线信道质量不稳定、网络拓扑瞬息万变、无线链路寿命短、带宽受限、通信负载量大等多重挑战.因此，如何将数据及时而可靠地传输到"城市大脑"，已成为一个研究热点.考虑存储成本、丢包惩罚与传输奖励，首先提出了面向VANET的混合流调度策略，为不同优先级的数据流分配传输资源；结合链路状况，接着提出了VANET中混合流调度与路径选择联合优化的数据传输策略，满足了强实时数据流对传输时延的需求，同时提高了弱实时数据流的传输可靠性.大量的仿真实验与性能分析表明，这些策略能够为VANET中数据传输提供QoS保障.     

Impact of probabilistic vehicle estimates on communication reliability at intelligent crossroads

Due to the safety-critical nature of intelligent crossroads, ensuring communication reliability between vehicles and the corresponding road side unit (RSU) is of utmost importance. This requires knowledge of the maximum number of vehicles in the system to be able to assess interference. However, due to the open-ended nature of the application, i.e., vehicles can enter and leave at arbitrary points in time, it becomes difficult and inefficient to perform an analysis based on deterministic methods. For this reason, this paper instead proposes a probabilistic technique to estimate the maximum vehicle count at crossroads. To this end, we investigate how different factors like traffic protocol, vehicle density, and vehicle length influence probabilistic estimates of the maximum vehicle count. We then highlight how these estimates impact communication reliability by deriving guarantees towards packet loss in an exemplary crossroad vehicular ad-hoc network (VANET). As shown in a detailed case study and simulations using OMNeT++, pessimism and overdesign can significantly be reduced compared to deterministic approaches, while still maintaining high safety levels.     

车联网中基于雾计算和多TA的条件隐私保护认证方案

车联网在生活中扮演着越来越重要的角色,它可以有效地防止交通拥堵从而减少交通事故。然而,在车联网中总是有非法车辆试图接入车联网并发布虚假消息。此外,现有方案多数存在计算效率低下的问题。针对上述存在的问题进行了研究,提出了一种车联网中基于雾计算和多TA的条件隐私保护认证方案。在保护车辆用户身份的条件下实现了车辆、雾节点、TA三者之间的身份认证,且在车辆追踪阶段可以还原车辆用户的真实身份,从而实现条件隐私保护。雾计算的使用降低了方案的计算和通信开销,同时多TA模型的使用也解决了单TA单点故障的问题。安全性证明和性能分析的结果表明该方案是安全且高效的。最后对当前方案进行了总结以及对未来研究作出了展望。     

基于HSV颜色空间的山区道路中的车牌定位

分析了目前我国山区道路交通事故的路况影响因素及其与山区道路交通事故之间的关系。结合地区的交通发展状况利用全概率公式测算出各因素可能导致交通事故的概率及相应的危险系数;在实时勘测各因素的基础上,结合样本库中的数据,判断出车辆是否处于安全状态,对于处于非安全状态的车辆进行车牌定位。     

Exploiting blockchain for dependable services in zero-trust vehicular networks

The sixth-generation (6G) wireless communication system is envisioned be cable of providing highly dependable services by integrating with native reliable and trustworthy functionalities. Zero-trust vehicular networks is one of the typical scenarios for 6G dependable services. Under the technical framework of vehicle-and-roadside collaboration, more and more on-board devices and roadside infrastructures will communicate for information exchange. The reliability and security of the vehicle-and-roadside collaboration will directly affect the transportation safety. Considering a zero-trust vehicular environment, to prevent malicious vehicles from uploading false or invalid information, we propose a malicious vehicle identity disclosure approach based on the Shamir secret sharing scheme. Meanwhile, a two-layer consortium blockchain architecture and smart contracts are designed to protect the identity and privacy of benign vehicles as well as the security of their private data. After that, in order to improve the efficiency of vehicle identity disclosure, we present an inspection policy based on zero-sum game theory and a roadside unit incentive mechanism jointly using contract theory and subjective logic model. We verify the performance of the entire zero-trust solution through extensive simulation experiments. On the premise of protecting the vehicle privacy, our solution is demonstrated to significantly improve the reliability and security of 6G vehicular networks.     

基于车流信息的车载自组织网络路由协议*

车载自组织网络(VANET)具有高移动性和间歇连通性,而且拓扑变化频繁,特别是在事故或交通堵塞的时候,因此,采用了携带并转发的方式,即移动车辆携带数据直到遇见有可转发的车辆。与现有携带并转发的解决方法不同,本文采用分布式实时估计各路段延时的方法。基于对各路段延时的估计,车辆就能计算车低延时的路由路径,然后提出了分布式实时数据流统计辅助的路由协议(DRTAR)来转发数据。实验结果显示,提出的DRTAR协议性能优于其他算法。     

延迟评估的车载自组织网络数据传输协议

车载自组织网络(VANET)作为一种新的自组织网络,可以极大提高驾驶安全性和交通运输的效率。由于车辆行驶导致的快速拓扑变化,使得设计高效的数据传输协议在车载自组织网络研究中成为挑战。分析了车辆自组织网络的特征,在道路统计信息的基础上,依据不同车辆的行驶方向,提出了一种新的基于延迟评估的车载自组织网络数据传输协议(DEF)。模拟实验证明提出的协议比现有协议具有更低的平均传输延迟。     

基于小波变换的车辆牌照定位研究

车辆牌照的准确定位是智能交通中车辆牌照识别技术的关键,提出一种基于小波变换的车牌质心定位方法,该方法可以很好地解决复杂背景与光照下的车牌定位.经过小波分析的车牌图像利用数学形态学进行车牌特征提取,对特征提取后的车牌图像采用连通区域质心的方法对车牌进行定位,最终得到车牌的准确区域.实验结果表明,该方法能够实现车牌的快速准确定位,是一种有效的车牌定位方法.