一个VANETs隐私保护实用化系统

针对车辆自组网(VANETs)中的身份和位置隐私保护问题,提出一个面向实用的VANETs隐私保护系统PKU-VPPS,给出该系统的体系架构设计并进行分析和研究。PKU-VPPS系统以TP4RS协议、TC-TPS协议、VLSP协议等为关键技术支撑点,不仅具有对车辆身份隐私和位置隐私进行安全保护能力,还具备良好的实际部署能力和可扩展能力。     

城市车联网中基于路径权值的路由算法

有效的数据传输是车联网(vehicular Ad Hoc networks,VANETs)应用的基本要求,为此,针对VANETs城市场景,提出基于路径权值的路由算法PWRA(path weight based routing algorithm)。从可用路径中选择最可靠的路径,利用网关车辆辅助不同路段间的连通;利用路径连通寿命、平均邻居数以及路径跳数3个参数估计路径权值,选择权值最大的路径传输数据包。仿真结果表明,相比基于贪婪边界转发路由GPSR(greedy perimeter stateless routing)和按需距离矢量路由(Ad Hoc on demand distance vector routing,AODV),PWRA算法的数据包传输率、端到端传输时延性能得到了有效提高。     

IGR:面向车载网的基于地理信息的数据传输协议

由于车辆的高速移动和拓扑的动态变化,基于地理信息的数据传输协议被广泛应用于车载网.然而,现存的多数协议在路由决定时并没有考虑链路的质量,导致数据包丢失率升高,增加了传输时延.为此,提出了新的基于地理信息的数据包传输协议(IGR).IGR协议在路由决策时充分考虑车辆的移动方向、位置和链路质量3项信息.其中,利用beacon接收率体现链路质量.将这3项信息融合成节点权值.源节点择优选择权值高的节点作为下一跳转发节点.与同类协议相比,提出的IGR协议具有低的传输时延和高的传输率.     

基于802.11p协议改进的车辆测距算法

随着交通事故的增长和智能交通的发展,基于车辆碰撞预警和交通管理的新服务引起了广泛关注。目前,基于全球导航卫星系统(GNSS)的定位技术已应用到车辆环境中。由于GNSS存在的盲区(例如森林,隧道等)会导致定位结果不准确,在车辆自组织网络(VANET)中,提出了基于IEEE 802.11p标准的定位方法。提出了用IEEE 802.11p短前导码的高效到达时间(TOA)或测距估计方法,以降低低信噪比(SNR)的影响。使用了自相关和互相关(混合相关)来执行到达时间(TOA)估计,对相关结果进行间隔求和的方法以达到更精确定位的目的。在加性高斯白噪声(AWGN)信道中的仿真结果表明:在低SNR条件中,提出的测距方法相比传统方法达到了更高的精度。     

车联网VANETs中一种分发紧急消息的广播方案

车载网VANETs中的车间通信V2V能够实现车间紧急消息的传递。然而,传统的广播算法采用RTB和CTB握手机制,同时在传递消息后,还需确认ACK环节,降低了紧急消息传递速度、增加了传输时延。为此,提出了一种广播紧急消息的新型算法。该算法利用数据包的信噪比SNR和节点位置坐标信息计算最大竞争窗口,再在最大竞争窗口内随机选择一个时隙用于转发紧急消息,避免了RTB/CTB握手机制。当源节点收到重播的紧急消息,表明紧急消息已成功传到下一节点,将其作为抑制源节点再广播紧急消息指标,避免了ACK确认环节,从而提高了紧急消息的传播效率和速度,降低了传输时延。     

VANETs中通信有效的门限匿名认证方案

在保证可靠性、匿名性和可审核性的同时,提高执行效率和降低通信成本是车载自组织网络( VANETs)的研究热点。针对现有匿名认证方案计算量较大和通信成本较高的问题,提出一种通信有效的门限匿名认证方案。采用基于身份的签名算法提高执行效率,使原始信息可从签名中恢复,从而降低通信成本,利用门限转发机制实现信息的可靠性,使用假名保证发送者的匿名性,通过追踪和撤销机制实现可审核性。分析结果表明,与已有的门限匿名认证方案相比,该方案在保证安全性的同时,具有较低的通信成本和较高的执行效率。     

Security on VANETs: Privacy, misbehaving nodes, false information and secure data aggregation

This article is a position paper on the current security issues in Vehicular Ad hoc Networks (VANETs). VANETs face many interesting research challenges in multiple areas, from privacy and anonymity to the detection and eviction of misbehaving nodes and many others in between. Multiple solutions have been proposed to address those issues. This paper surveys the most relevant while discussing its benefits and drawbacks. The paper explores the newest trends in privacy, anonymity, misbehaving nodes, the dissemination of false information and secure data aggregation, giving a perspective on how we foresee the future of this research area.First, the paper discusses the use of Public Key Infrastructure (PKI) (and certificates revocation), location privacy, anonymity and group signatures for VANETs. Then, it compares several proposals to identify and evict misbehaving and faulty nodes. Finally, the paper explores the differences between syntactic and semantic aggregation techniques, cluster and non-cluster based with fixed and dynamic based areas, while presenting secure as well as probabilistic aggregation schemes.     

基于区块链的车联网信任机制

车联网（VANETs）中虚假的共享信息会导致负面影响。针对车辆间的信任缺失现象,提出了一种基于区块链的信任解决方案。通过引入贝叶斯推理,基于先验概率进行信任评估,综合考虑了消息可信度和源节点自身可信度。通过超级账本实现信任管理,路侧单元（RSU）将汇聚车辆提交的评价形成信任值并创建区块,利用智能合约进行信任值初始化、查询和更新操作。仿真结果显示,提出方案能有效进行信任评估,准确识别虚假消息。同时与现有方案对比表明,该方案具有更高吞吐量和更低时延,适用于车联网的轻量级资源消耗环境。     

An intelligent hybrid prairie dog optimization algorithm-based stable cluster reliable routing scheme for VANETs

Vehicular ad hoc network (VANET) is most significant for supporting intelligent transportation system (ITS)-based technologies, but it gets hurdled by sparse distribution of vehicles on highways, and dynamically challenging topology that arises due to increase in traffic. Hence, energy stable and optimized cluster construction maximizes the network lifetime. In this paper, Hybrid Prairie Dogs and Beluga Whale Optimization-based Node Clustering (HPDBWOA-NC) mechanism is proposed with the parameters of highway route, node velocity, number of vehicular nodes, and communication for achieving stable cluster construction in VANETs. It is proposed with the balanced exploration and exploitation potential of Prairie Dog Optimization Algorithm (PDOA) and Beluga Whale Optimization Algorithm (BWOA) for establishing optimal clusters that increase the network stability during the routing process. It integrated the exploration and exploitation capabilities of PDOA and BWOA and confirmed better optimized clusters which confirmed reliable data delivery by preventing the issue of premature convergence. It constructed clusters and selected cluster heads (CHs) depending on the fitness factors of energy, interdistance between vehicles, communication range, and vehicular density. The results of the proposed HPDBWOA-NC generated optimal number of CHs in the network which is comparatively 34.21% better than the benchmarked mechanisms. The mean throughput and packet delivery ratio (PDR) achieved by the proposed HPDBWOA-NC are identified to be significantly improved by 25.48% and 28.91% better than the investigated metaheuristic clustering protocols. The statistical study also guaranteed an increased factor of 81, during the processing of optimizing the clusters during the employment of ITS applications in VANETs.     

面向城市VANETs的多跳警告广播协议

为改善道路交叉口处信息向所有方向分发的可靠性以及降低信息分发时延,提出面向城市车载网络多种交通密度、基于位置的多跳警告广播协议MBW.本协议把无线信号一次发射覆盖的道路分为东、南、西、北4个方向.道路交叉路口的中继节点满足两个条件:首先,一个节点至少有两个邻居节点,该节点及邻居的行驶方向都不同,并且与邻居节点之间的距离都大于路宽;其次,ID号在交叉口的节点中最小,交叉路口处中继节点优先广播信息不等待.道路上的中继节点根据WT公式确定,WT值为零时转发信息,并定义此节点为中继节点,本协议支持信息在路上双向传输.MBW协议的中继节点选择策略能够减少中继节点个数和信息分发冗余.仿真结果表明MBW协议和现存的VANETs广播协议相比具有较好的高覆盖率、低延迟、低转发节点率和较低的网络开销.