Privacy Addressing-Based Anonymous Communication for Vehicular Ad Hoc Networks

Vehicle ad-hoc network (VANET) technology is a basic component of the future intelligent transportation system. With the advances in modern information society, privacy issues have become important considerations. However, most routing proposals for VANETs lack privacy support, namely anonymity or pseudonymity and unlinkability aspects. This paper presents a novel privacy addressing-based anonymous communication approach for VANETs, which prevents eavesdroppers from identifying a particular vehicle by its address. The proposed scheme is a kind of end-to-end solution, so it can potentially be extended to work with many traditional routing protocols. Finally, the simulation results show that the proposed scheme outperforms previous approaches with privacy support in terms of protocol overhead and packet latency.     

车载自组织网络的体系结构和通信协议研究

在对车载自组织网络的特点和研究现状分析的基础上,文章给出了车载自组织网络（VANET）中多维多层的理论模型和网络体系结构,讨论了物理层技术及其相关标准以及MAC层、网络层协议设计的重点和难点,阐述了广播协议的设计思路。     

An Enhanced Secure Authentication Scheme for Vehicular Ad Hoc Networks Without Pairings

Wireless Personal Communications - In the recent paper, Nai-Wei Lo and Jia-Lun Tsai mathematically proposed an efficient authentication scheme for vehicular sensor network. It uses elliptic curve...     

Structured Peer-to-Peer Real Time Video Transmission over Vehicular Ad Hoc Networks

Video communication over Vehicular Ad Hoc Networks (VANET) has several applications such as road safety, commercial advertisements and on-road entertainment. In this paper we present a structured peer-to-peer (P2P) network designed for the distribution of live-content, with low bandwidth consumption, within a VANET. This P2P network is modelled using a media distribution graph. The implementation of a structured network allows a peer to schedule consecutive data chunks produced by the media source by means of a scheduling algorithm. In our analysis we obtain a bound for the maximum delay between the media source and any of the peers of the network and the buffer size needed to allow consecutive scheduling. We study a type of media distribution graph and we calculate its order and diameter, which means that under stable conditions we can ensure certain quality-of-service parameters. The results of simulation over NS2 show the fitness of the mathematical analysis.     

车载网络中的数据分发策略

通过车载网络(VAETNs)能够有效提高交通管理系统(TMS)的数据传输。然而,由于通信距离短以及车辆的移动,完成VANETs中的数据传输是一项挑战任务。为此,提出基于复杂网络指标的数据传输(MCDD)策略。MCDD策略依据二跳邻居的信息,并通过介数中心性和度中心性两项性能指标选择转发节点,进而降低开销和缩短传输时延。仿真结果表明,相比于基于区划分的全-分布式流量管理系统(FTMS),MCDD策略的交通拥塞时间缩短了约48.95%,平均行驶速度提高了约8%。     

Analytical Model for Connectivity in Vehicular Ad Hoc Networks

We investigate connectivity in the ad hoc network formed between vehicles that move on a typical highway. We use a common model in vehicular traffic theory in which a fixed point on the highway sees cars passing it that are separated by times with an exponentially distributed duration. We obtain the distribution of the distances between the cars, which allows us to use techniques from queuing theory to study connectivity. We obtain the Laplace transform of the probability distribution of the connectivity distance, explicit expressions for the expected connectivity distance, and the probability distribution and expectation of the number of cars in a platoon. Then, we conduct extensive simulation studies to evaluate the obtained results. The analytical model that we present is able to describe the effects of various system parameters, including road traffic parameters (i.e., speed distribution and traffic flow) and the transmission range of vehicles, on the connectivity. To more precisely study the effect of speed on connectivity, we provide bounds obtained using stochastic ordering techniques. Our approach is based on the work of Miorandi and Altman, which transformed the problem of connectivity distance distribution into that of the distribution of the busy period of an equivalent infinite server queue. We use our analytical results, along with common road traffic statistical data, to understand connectivity in vehicular ad hoc networks.      

Routing in Sparse Vehicular Ad Hoc Wireless Networks

A vehicular ad hoc network (VANET) may exhibit a bipolar behavior, i.e., the network can either be fully connected or sparsely connected depending on the time of day or on the market penetration rate of the wireless communication devices. In this paper, we use empirical vehicle traffic data measured on 1-80 freeway in California to develop a comprehensive analytical framework to study the disconnected network phenomenon and its network characteristics. These characteristics shed light on the key routing performance metrics of interest in disconnected VANETs, such as the average time taken to propagate a packet to disconnected nodes (i.e., the re-healing time). Our results show that, depending on the sparsity of vehicles or the market penetration rate of cars using Dedicated Short Range Communication (DSRC) technology, the network re-healing time can vary from a few seconds to several minutes. This suggests that, for vehicular safety applications, a new ad hoc routing protocol will be needed as the conventional ad hoc routing protocols such as Dynamic Source Routing (DSR) and Ad Hoc On-Demand Distance Vector Routing (AODV) will not work with such long re-healing times. In addition, the developed analytical framework and its predictions provide valuable insights into the VANET routing performance in the disconnected network regime.     

基于车载自组织网络的消息发送时机研究

车载自组织网络(VANET)是一种节点迅速移动的无线自组织网络,网络的动态密度变化具有明显的特征,呈现出疏密相间的"手风琴"现象。利用汽车之间相遇的机会进行通信需要考虑到网络动态变化对传输的影响。文章利用仿真软件SUMO生成的跟踪轨迹文件,在仿真软件ONE下做网络参数的对比实验。通过模拟道路交通的网络动态密度变化,文章得到结论:最佳发送时机随网络参数不同而变化。     

一种基于可靠性的车载自组织网络路由算法

提出了一种改进的GPSR路由算法.该算法在选择转发节点过程中同时考虑位置和方向,进而提高转发节点选择的正确性来增加通信链路可靠性.用VanetMobisim交通仿真软件构建真实的VANETs网络城市场景,结合NS-2进行仿真研究,结果表明,和传统GPSR算法相比,改进的GPSR路由算法在端到端时延影响不大的条件下,能够有效地提高数据包传递率,降低数据丢包率.因此,改进的GPSR协议更适用于对实时性要求不高、而对可靠性要求较高的VANETs网络.     

Trustworthy Privacy-Preserving Car-Generated Announcements in Vehicular Ad Hoc Networks

Vehicular ad hoc networks (VANETs) allow vehicle-to-vehicle communication and, in particular, vehicle-generated announcements. Provided that the trustworthiness of such announcements can be guaranteed, they can greatly increase the safety of driving. A new system for vehicle-generated announcements is presented that is secure against external and internal attackers attempting to send fake messages. Internal attacks are thwarted by using an endorsement mechanism based on threshold signatures. Our system outperforms previous proposals in message length and computational cost. Three different privacy-preserving variants of the system are also described to ensure that vehicles volunteering to generate and/or endorse trustworthy announcements do not have to sacrifice their privacy.     

车载自组网中的网络与信息安全

因自组织网络无中心的特点,传统有中心网络中成熟的安全保障机制无法得到直接应用。为了使车载通信技术得到更加广泛的应用,安全问题必须得到很好的解决。文章对车载自组网的安全需求及目标进行分析,然后从安全路由、密钥管理和入侵检测3个方面对车载自组网安全研究的现状进行介绍。在这3个方面中,安全路由研究最为广泛,而密钥管理则是保障车载自组网安全的关键。     

A Hybrid Collision Avoidance Scheme for Ad Hoc Networks

A novel hybrid collision avoidance scheme that combines both sender-initiated and receiver-initiated collision-avoidance handshake is proposed for multi-hop ad hoc networks. The new scheme is compatible with the popular IEEE 802.11 MAC protocol and involves only some additional queue management and book-keeping work. Simulations of both UDP- and TCP-based applications are conducted with the IEEE 802.11 MAC protocol, a measurement-based fair scheme and the new scheme. It is shown that the new scheme can alleviate the fairness problem with almost no degradation in throughput. More importantly, it is shown that without explicit information exchange among nodes, the fairness problem cannot be solved conclusively if reasonable throughput is to be maintained. Hence it calls for further work to integrate the new collision avoidance scheme with other schemes that approximate fair queueing and use more contention information in channel access to achieve some QoS assurances in ad hoc networks.     

基于身份的车联网消息认证方案

本文对车联网中常用的椭圆曲线消息认证方法进行比较分析,对现有的方案改进,并对该方案进行了性能分析,在安全性不变的前提下,仿真结果表明增加了19％通信开销,但是消息验证阶段计算开销提升80％以上,签名阶段提升22％.     

A Pairing-Free Certificateless Signcryption Scheme for Vehicular Ad Hoc Networks

Vehicular ad hoe networks (VANETs) cre-ate an vital platform for communication between vehicles,which can realize accident warning,auxiliary driving,road traffi...     

An Intelligent Scheme for Slot Reservation in Vehicular Ad Hoc Networks

Vehicular ad hoc network is a solution for increasing road traffic demand.Non-safety messages are sent during the service channel interval.The slots during whic...     

一维车载Ad Hoc网络连接度分析

In this paper we analyze connectivity of one-dimensional Vehicular Ad Hoc Networks where vehicle gap distribution can be approximated by an exponential distribution. The probabilities of Vehicular Ad Hoc Network connectivity for difference cases are derived. Furthermore we proof that the nodes in a sub-interval [z1,z1 +Δz] of interval [0, z], z>0 where all the nodes are independently uniform distributed is a Poisson process and the relationship of Vehicle Ad hoc Networks and one-dimensional Ad Hoc networks ...     

Detecting Hot Road Mobility of Vehicular Ad Hoc Networks

Vehicular Ad Hoc Networks (VANETs) can provide value-added services to both drivers and passengers with on-board vehicular communication systems. Node mobility and volatile wireless connection in VANETs affect inter-contact time (T _I ) between mobile nodes, which greatly degrades the performance of vehicular applications. Nevertheless, the node spatial distribution in VANETs is another important factor especially in real applications. It positively affects the inter-contact time of vehicular nodes. By leveraging it, we can significantly improve the performance of data transmissions and inter-vehicle communication. To this end, we investigate the data collected from around 4,000 taxisin Shanghai and propose in this paper an efficient hot road mobility model. We find that most taxis distribute on some hot roads, which makes the node spatial distribution follow the power law. Based on this observation, we propose the concepts of indirect contact and heterogeneous inter-contact time (T _H ) to reveal how hot roads can change the distribution of inter-contact time. We find that the tail distribution of T _H also appears the power law, and both node spatial distribution and T _H distribution decay at least as the power law. We further propose a model for detecting vehicle mobility in hot roads, which can generates synthetic traces that captures both spatial and temporal features of nodes in VANETs.