基于运行轨迹特征分析的车辆自组织网路由算法

首先基于车辆trace数据提取了粗粒度的车辆移动信息,在此基础上,继续研究了trace数据的细粒度的车辆移动模型;然后基于移动模型提出了车辆自组织网络的路由算法（RPT-D）,根据车辆移动特征将报文更快地传输到目的地;接着将对传输的QoS需求放入报文选路目标中,得到扩展性和选路结果更好的RPT-GA算法;最后通过仿真实验,分别从传输时延、投递成功率、跳数和辅助报文数量等4个性能参数角度,基于车辆trace数据将所提出的路由算法与经典的车辆自组织网路由算法（IGRP和GPSR）进行比较,实验结果验证了所提算法的有效性。     

A new position based routing algorithm for vehicular ad hoc networks

Telecommunication Systems - Recently, the increasing demand for low latency, the explosive growth in the volume of network traffic, the large and growing number of connected devices, and...     

Cluster based emergency message broadcasting technique for vehicular ad hoc network

Broadcasting is one of the major emergency services of Vehicular ad hoc network, since the number of vehicles increases every day. Because of the high density of the vehicles, it is necessary to broadcast emergency messages to all the vehicles to avoid traffic jam and vehicle accidents. Reliable broadcasting of messages in self-organizing Ad hoc networks is a promising research field. In this paper a cluster based emergency message broadcasting algorithm is proposed. In this regard we have proposed cluster based architecture for emergency message dissemination and collision avoidance in VANET. In this paper, first the formation of cluster is done in such a way that it avoids any kind of collision. Once cluster head is selected it takes the responsibility of intra cluster management to avoid interference between the clusters. To increase the reliability during emergency message dissemination two MAC layer broadcasts protocol is used. This assures that message is delivered on time without any hazards. The proposed model is simulated for DSDV, AODV, and DSR protocols with the standards 802.11 and 802.11p in SHWM, Manhattan and freeway mobility models.     

一种基于北斗的混合式无线自组网系统设计

在林业、消防、治安反恐、军事等领域,任务单元之间灵活、可靠的动态自组网数据传递,是提高一体化指挥能力和快速响应能力的关键所在。传统的无线局域自组网技术易受距离、遮挡等条件限制,在大区域、有遮挡条件下的应用有一定局限性。文章基于北斗系统定位和短报文通信能力,结合无线局域自组网技术,利用北斗应用终端设备为骨干构建了分层编组逻辑网络,有效扩大了覆盖范围和增强了组网可靠性。不同参数的网络变化与修复过程的仿真表明,该系统能够实现动态环境中网络修复与重组,提供可靠通信保障,解决了多种场合下所需的精确、无间断一体化指挥要求。     

RSU-coordinated multichannel MAC protocol in vehicular ad hoc network

A road side unit (RSU)-coordinated multichannel media access control (MAC) (RMM) protocol was proposed in vehicular ad hoc network,which aimed to improve the transmission efficiency of non-safety messages.Under the coordination of RSU,nodes had more opportunities to make SCH reservations on control channel,and the contention-free message transmissions were thus realized.The proposed RMM protocol could use the service channel during the whole synchronization interval for non-safety message transmissions,and thus the saturated network throughput and channel utilization were improved,and the transmission delay was reduced.Compared with other existing protocols,extensive analysis and simulation results demonstrate the superiority of the RMM protocol.     

ad hoc网络中一种基于信任模型的机会路由算法

由于ad hoc网络具有缺乏足够的物理保护、拓扑结构动态变化、采用分布式协作、节点的带宽和计算能力有限等特点,导致传统的路由安全机制不再适合ad hoc网络路由协议的设计。最近当前研究热点之一的机会路由能够在链路不可靠的情况下充分利用无线广播和空间多样性的特性提高网络的吞吐量。因此,考虑在机会路由中引入信任相似性概念设计信任机会路由,建立了基于节点信任度和最小成本的信任机会转发模型,提出了最小成本的机会路由算法MCOR,并对算法进行了理论上的分析和证明。最后采用仿真实验对该算法进行验证,又与经典机会路由协议ExOR以及其他经典的信任路由协议TAODV和Watchdog-DSR进行性能对比。仿真结果表明,MCOR算法能够防范恶意节点的攻击,在吞吐量、端到端时延、期望转发次数(ETX)和成本开销等方面都比其他3种协议表现出性能上的优势。     

车载自组织网中基于蚁群算法的延迟感知路由协议

针对城市道路环境下车载自组织网( VANETs)中通信性能下降以及数据传输失败的问题,提出了一种基于蚁群算法的延迟感知路由( ACDR)协议。首先,建立双向车道的数学延迟模型;然后,根据提出的端点十字路口( EI)的概念,ACDR利用蚁群优化( ACO)寻找最佳路线,其中前向蚂蚁根据本地路段延迟以及当前十字路口与目的节点的端点十字路口之间的全局时延来选择路径,后向蚂蚁则负责在返回路径时更新信息素,同时,相邻十字路口之间利用贪婪转发算法进行数据包的传递。最后仿真比较了ACDR协议与连通性感知路由( CAR)协议的性能,结果表明提出的ACDR协议的数据包的传输延迟小,丢包率低,通信性能好。     

浅析车载自组织网络通信系统的设计与实现

车载自组织是构成职能交通的重要组成部分,能够实现道路上的车辆之间、车辆与道路之间状况的互相通信。其通过车载自组织网络通信系统能够显著降低交通事故,为交通部分提供办案依据。文章主要对车载自组织网络通信系统的设计进行分析,并进一步探讨了车载应用系统实用化。     

Research on video streaming media cooperative downloading in vehicular ad hoc network

The same direction multi-hop downloading network flow model was proposed for vehicle communication range and channel competition under forwarding.According to the model and video streaming media characteristic,the same & opposite direction cooperative downloading quality of service (SODCD-QoS) scheme was presented.First,the same direction vehicles helped the target vehicle to achieve multi-hop cooperative downloading.It can reduce the waste of time which the target vehicle has to wait for opposite direction cooperative vehicle.Secondly,the next base stations loaded data into eligible opposite direction vehicles according to vehicles option strategy based on time first or picture quality first.Then the opposite direction vehicles helped the target vehicle to achieve one-hop cooperative downloading.NS simulations show that the SODCD-QoS scheme is better than DSRelay and VCoDS algorithm in terms of download time.Further,the new scheme can maintain good picture quality PSNR.     

基于城市公共交通云的车联网通信模式研究

在当前交通环境中,大量公交车或出租车上存在可以连入Internet的网络节点,其中很多节点还具有一定的计算和存储能力,根据这一特点建立一种在公共交通基础上的移动云服务与车联网的通信模式,通过在OMNe T++和SUMO平台上进行仿真,验证这种方式下车辆在交通环境下数据的传输可行性。     

车载网中面向高速场景的路由算法

有效地传输数据是提高车联网应用性能的关键。而动态的拓扑结构,给车联网的数据传输提出了挑战。为此,提出基于路径连通概率的车联网路由算法CPB。首先,依据高速公路场景,建立一维车辆移动模型,然后再计算链路的连通概率,最后,计算路径的连通概率,并选择连通概率最高的路径传输数据。仿真结果表明,提出的CPB算法能够有效地提高数据包传递率、端到端传输时延以及吞吐量性能。     

Fireworks: an intelligent location discovery algorithm for vehicular ad hoc networks

Searching for and locating a certain destination in a vehicular ad-hoc network (VANET) are fundamental issues to ensure routing and data dissemination under high mobility and lack of fixed infrastructure. However, naive-flooding searching is too expensive and takes a considerable amount of valuable bandwidth in the network. To overcome this, GPS information of the vehicles can be exploited, which can aid searching and routing in VANETs. In this paper, we present a novel position-based searching algorithm—called Fireworks—that can be used as a location discovery algorithm in VANETs. The proposed scheme is purely reactive and has a limited usage of beacons. Fireworks algorithm provides the position of the destination vehicle without having a Location Information System infrastructure or a proactive mechanism. We show that the method is efficient and reliable while greatly reducing the searching overhead. The simulations show that the algorithm covers as many nodes as naive-flooding with less than one-fifth of the broadcast messages and with less than one-third of the Dynamic Source Routing (DSR). It also performs better than Acknowledgement-Based Broadcast Protocol (ABSM) in terms of total number of broadcast messages, node coverage speed and query success rate.     

Security in vehicular ad hoc networks [security in mobile ad hoc]

Vehicular communication networking is a promising approach to facilitating road safety, traffic management, and infotainment dissemination for drivers and passengers. One of the ultimate goals in the design of such networking is to resist various malicious abuses and security attacks. In this article we first review the current standardization process, which covers the methods of providing security services and preserving driver privacy for wireless access in vehicular environments (WAVE) applications. We then address two fundamental issues, certificate revocation and conditional privacy preservation, for making the standards practical. In addition, a suite of novel security mechanisms are introduced for achieving secure certificate revocation and conditional privacy preservation, which are considered among the most challenging design objectives in vehicular ad hoc networks.     

HOPNET: A hybrid ant colony optimization routing algorithm for mobile ad hoc network

Mobile ad hoc network (MANET) is a group of mobile nodes which communicates with each other without any supporting infrastructure. Routing in MANET is extremely challenging because of MANETs dynamic features, its limited bandwidth and power energy. Nature-inspired algorithms (swarm intelligence) such as ant colony optimization (ACO) algorithms have shown to be a good technique for developing routing algorithms for MANETs. Swarm intelligence is a computational intelligence technique that involves collective behavior of autonomous agents that locally interact with each other in a distributed environment to solve a given problem in the hope of finding a global solution to the problem. In this paper, we propose a hybrid routing algorithm for MANETs based on ACO and zone routing framework of bordercasting. The algorithm, HOPNET, based on ants hopping from one zone to the next, consists of the local proactive route discovery within a node’s neighborhood and reactive communication between the neighborhoods. The algorithm has features extracted from ZRP and DSR protocols and is simulated on GlomoSim and is compared to AODV routing protocol. The algorithm is also compared to the well known hybrid routing algorithm, AntHocNet, which is not based on zone routing framework. Results indicate that HOPNET is highly scalable for large networks compared to AntHocNet. The results also indicate that the selection of the zone radius has considerable impact on the delivery packet ratio and HOPNET performs significantly better than AntHocNet for high and low mobility. The algorithm has been compared to random way point model and random drunken model and the results show the efficiency and inefficiency of bordercasting. Finally, HOPNET is compared to ZRP and the strength of nature-inspired algorithm is shown.     

Simplified gateway selection scheme for multihop relay in vehicular ad hoc network

Integrating vehicular ad hoc network (VANET) and universal mobile telecommunication system (UMTS) could be a promising architecture for future machine‐to‐machine applications. This integration can help vehicles have steady Internet connection through the UMTS network and in communicating with other vehicles. However, dead spot areas and unsuccessful handoff processes caused by the high speed of vehicles can disrupt the implementation of this kind of architecture. In this paper, a new simplified gateway selection (SGS) scheme for multihop relay in a VANET‐UMTS integration network is proposed. The proposed scheme extends the coverage or/and calming of the frequent handoff process and allows vehicles to continue to be connected to the UMTS infrastructure network. An integrated simulation environment that combines VanetMobiSim and NS2 is used to simulate and evaluate the proposed scheme. The simulation results show that the SGS scheme performed better when it was implemented with ad hoc on a demand distance vector routing and destination‐sequenced distance vector routing protocols. Furthermore, the SGS scheme is compared with other cluster‐based gateway selections used in the previous works. The results show that our SGS scheme outperforms other cluster‐based gateway selections scheme in terms of selection delay, control packet overhead, packet delivery ratio, and overall throughput. Copyright © 2013 John Wiley & Sons, Ltd.     

A path selection based routing protocol for urban vehicular ad hoc network (UVAN) environment

Routing in urban environment is a challenging task due to high mobility of vehicles in the network. Many existing routing protocols only consider density, link connectivity, delay, and shortest path information to send the data to the destination. In this paper, a routing protocol is proposed which uses the urban road network information such as multi-lane and flyover to send the data to the destination with a minimum packet forwarding delay. The next path for data forwarding is selected based on a path value calculated by the Road Side Unit for each path connected to a junction. This protocol uses Ground Vehicle to Ground Vehicle (GV2GV) communication, Flyover Vehicle to Flyover Vehicle (FV2FV) communication, and Flyover Vehicle to Ground Vehicle/Ground Vehicle to Flyover Vehicle (FV2GV/GV2FV) communication to enhance the routing performance. Simulation results show that proposed protocol performs better than P-GEDIR, GyTAR, A-STAR, and GSR routing protocols in terms of end-to-end delay, number of network gaps, and number of hops.     

Stable routing protocol based on fuzzy logic system in vehicular ad hoc networks

Vehicular ad‐hoc networks have several roles in alert messages dissemination between vehicles in danger, the most important role is to provide helpful information for drivers (eg, road traffic state). But, some performance improvements are frequently needed in terms of routing. Hence, several clustering approaches have been proposed to optimize the network services. These approaches are based on increasing data delivery, reducing data congestion, and dividing the traffic into clusters. However, a stable clustering algorithm is always required in order to ensure the data dissemination in a dense, mobile, or a large‐scale environment. Therefore, in this paper, we have proposed a stable routing protocol based on the fuzzy logic system, which can deliver alert messages with minimum delay and improve the stability of clusters structure by generating only a small number of clusters in the network. In this work, the fuzzy logic system has been used to create the clusters and select a cluster head for each cluster. We have used the network simulator (NS2) to generate the results. As a result, we could reduce the cluster head changes and increase the cluster member lifetime compared with recent approaches.     

A split reliable transport protocol over the vehicular ad hoc network communication environment

To have reliable transmission in the vehicular ad hoc network (VANET) environment, a split reliable transport protocol (SRTP) is proposed in this paper. The basic idea of SRTP is to separate a long connection into several subconnections in order to reduce the overhead of packet retransmission, in which the length of each subconnection depends on links’ states between vehicles. Three main issues that need to be resolved for SRTP are the following: (i) how to decide the length of each subconnection when a connection is established initially; (ii) how to enhance the connection's stability after the connection is established to deal with the fast topology change in the VANET environment; and (iii) how to deal with packet congestion. An estimative scheme using location and speed information of vehicles to estimate the connectivity time of the links between vehicles are used in SRTP. The estimated values can be used to decide the lengths of subconnections and adjust them dynamically. Another mechanism named channel busy rate aware congestion avoidance is proposed to avoid network congestion in the ad hoc network environment. The simulation results show that SRTP can be operated well in the VANET environment, and the aforementioned three issues can be appropriately resolved. Copyright © 2014 John Wiley & Sons, Ltd.     

车载自组网的现状与发展

简要介绍了车载自组网的发展历史、特点和应用领域。使用分析和比较的方法，讨论各种无线通信技术用于车载自组网的优缺点，并针对车载自组网的应用及特性提出搭建车间通信系统的设计思想和突破方向。为了便于读者跟踪国外先进的研究成果，还介绍了一些在这一领域比较活跃的研究机构以及他们的主要工作。