In this paper we analyze connectivity of one-dimensional Vehicular Ad Hoc Networks where vehicle gap distribution can be approximat- ed by an exponential distribution. The probabilities of Vehicular Ad Hoc Network con...In this paper we analyze connectivity of one-dimensional Vehicular Ad Hoc Networks where vehicle gap distribution can be approximat- ed 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 ＋ △z] 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 where nodes independently uniform distributed in [zl, z1 ＋ △z] is explained. The analysis is validated by computing the probability of network connectivity and comparing it with the Mont Carlo simu- lation results.展开更多
Due to high node mobility, stability has been always one of the major concerns of vehicle clustering algorithms in vehicular ad hoc networks. In this paper, we propose a novel clustering algorithm based on the informa...Due to high node mobility, stability has been always one of the major concerns of vehicle clustering algorithms in vehicular ad hoc networks. In this paper, we propose a novel clustering algorithm based on the information of routes planned by vehicular navigation systems. In the clustering algorithm, we design a residual route time function to quantitatively calculate the overlapping time among vehicles based on route information, with which a novel clusterhead selection metric is presented. We further design a mechanism of future-clusterhead, which can help avoid message exchanges at intersections and reduce the overhead of cluster maintenance. The simulation results show that, compared with previous works, our clustering algorithm can achieve higher stability and at the same time lower communication cost.展开更多
This paper comes up with a SDN Based Vehicle Ad-Hoc On-Demand Routing Protocol(SVAO),which separates the data forwarding layer and network control layer,as in software defined networking(SDN),to enhance data transmiss...This paper comes up with a SDN Based Vehicle Ad-Hoc On-Demand Routing Protocol(SVAO),which separates the data forwarding layer and network control layer,as in software defined networking(SDN),to enhance data transmission efficiency within vehicle ad-hoc networks(VANETs).The roadside service unit plays the role of local controller and is in charge of selecting vehicles to forward packets within a road segment.All the vehicles state in the road.Correspondingly,a two-level design is used.The global level is distributed and adopts a ranked query scheme to collect vehicle information and determine the road segments along which a message should be forwarded.On the other hand,the local level is in charge of selecting forwarding vehicles in each road segment determined by the global level.We implement two routing algorithms of SVAO,and compare their performance in our simulation.We compare SVAO with popular ad-hoc network routing protocols,including Optimized Link State Routing(OLSR),Dynamic Source Routing(DSR),Destination Sequence Distance Vector(DSDV),and distance-based routing protocol(DB)via simulations.We consider the impact of vehicle density,speed on data transmission rate and average packet delay.The simulation results show that SVAO performs better than the others in large-scale networks or with high vehicle speeds.展开更多
考虑到城市环境中障碍物对网络性能的重要影响,在NS2(Network Simulator version 2)中加入了代表障碍物的概率穿透模型,使仿真环境更接近真实环境。针对AODV(Ad hoc On-Demand Distance Vector Routing)协议应用在城市场景下的缺陷,提...考虑到城市环境中障碍物对网络性能的重要影响,在NS2(Network Simulator version 2)中加入了代表障碍物的概率穿透模型,使仿真环境更接近真实环境。针对AODV(Ad hoc On-Demand Distance Vector Routing)协议应用在城市场景下的缺陷,提出了一种改进的AODV协议——GE-AODV(Geocast Enhanced AODV)协议,该协议是基于位置信息的协议,并采用了多播方式来转发控制信息。仿真表明,GE-AODV降低了网络时延和控制开销,提高了网络可靠性。展开更多
随着车联网VANETs(Vehicular Ad hoc Networks)应用日益受到关注,研究者对VANETs路由协议进行了深入研究。为此,首先总结VANETs的特点及应用,再介绍了基于位置的、基于拓扑以及基于广播路由的概念,并着重分析和总结了近期路由协议的核...随着车联网VANETs(Vehicular Ad hoc Networks)应用日益受到关注,研究者对VANETs路由协议进行了深入研究。为此,首先总结VANETs的特点及应用,再介绍了基于位置的、基于拓扑以及基于广播路由的概念,并着重分析和总结了近期路由协议的核心思想以及特点,此外,还从应用场景、前提条件、虚拟设备要求、电子地图需求、路由恢复策略以及转发模式六个方面对路由协议进行全面比较,最后,展望了VANETs路由技术的未来研究方向。展开更多
Logical behavioral arrangements are a class of conventional arrangements to illustrate the happening of incidents in an appropriate and structured approach in vehicular ad hoc network （VANET）. These incidents are ch...Logical behavioral arrangements are a class of conventional arrangements to illustrate the happening of incidents in an appropriate and structured approach in vehicular ad hoc network （VANET）. These incidents are characterized as a list of path segments that are passed through by the vehicles for the duration of their journeys from a pre-decided local source to a local destination in a structured manner. A set of proper description illustrating the paths traversed by the vehicles as logical behavioral arrangements is describedin this paper. The data gathering scheme based on secure authentication to gather the data from the vehicles is proposed in this paper. This proposed data gathering scheme based on secure authentication is compared with the existing data gathering schemes by using veins framework and the results of analysis reflect that the proposed scheme outperforms among others. The data collected from the vehicles by the proposed data gathering scheme is stored at distributed road side units （RSUs）. From these collected paths, the common and frequent paths opted by the vehicles in a certain region are determined by using frequent arrangement mining approach. An estimation model is used to decidethe next path and the whole path map opted by the vehicles in unusual situations like accident, jams, or a particular time of day. The proposed scheme will helpthe society in reducing the waiting time in vent of emergency or normal working days.展开更多
车载网络(Vehicular ad hoc networks,VANETs)是一种特殊形式的网络,具有节点高速移动、拓扑频繁的变化的特性。这些特性为消息的传播带来挑战。路由机制是实现消息传递的关键因素。地理位置路由被广泛地应用于VANETS,要求节点周期广播b...车载网络(Vehicular ad hoc networks,VANETs)是一种特殊形式的网络,具有节点高速移动、拓扑频繁的变化的特性。这些特性为消息的传播带来挑战。路由机制是实现消息传递的关键因素。地理位置路由被广泛地应用于VANETS,要求节点周期广播beacon消息。然而,节点周期地广播beacon消息,降低了路由性能,特别是在城市区域,由于节点密集,每个节点均广播beacon消息,恶化了路由性能。为此,针对城市环境,提出基于beacon控制的路由协议RPBC(Routing protocol with beacon control)。在RPBC中,并非每个节点广播beacon消息,而设置有效的机制选择部分节点广播,从而降低了beacon冗余,同时,采用最短路径算法,减少数据传输跳数。仿真结果表明,提出的RBPC在分组投递率、端到端传输时延以及路由开销方面均有较好的性能。展开更多
Vehicular ad hoc networks （VANETs） that use the IEEE 802.11p communication standard face a number of challenges, not least when it comes to safety messages on the VANET control channel （CCH） where short delay time...Vehicular ad hoc networks （VANETs） that use the IEEE 802.11p communication standard face a number of challenges, not least when it comes to safety messages on the VANET control channel （CCH） where short delay times and reliable delivery are of pri- mary importance. In this paper we propose a vehicular machine-to-machine （VM2M） overlay network that uses Long Term Evolu- tion （LTE） physical random access channel （PRACH） to emulate VANET CCH. The overlay network uses dedicated preambles to separate vehicular traffic from regular LTE traffic and a cartier sense multiple access with collision avoidance （CSMA-CA） layer similar to the one used in IEEE 802.15.4 to avoid the four step handshake and the overhead it incurs. The performance of the pro- posed overlay is evaluated under a wide range of PRACH parameters which conform to the scenarios with high vehicle velocities and large distances between roadside units （RSUs） that may be encountered in rural areas and on highways.展开更多
基金supported by National Science Fund for Distinguished Young Scholars (No.60525110)National 973 Program (No. 2007CB307100, 2007CB307103)+2 种基金National Natural Science Foundation of China (No. 60902051)Chinese Universities Scientific Fund (BUP-T2009RC0505)Development Fund Project for Electronic and Information Industry (Mobile Service and Application System Based on 3G)
文摘In this paper we analyze connectivity of one-dimensional Vehicular Ad Hoc Networks where vehicle gap distribution can be approximat- ed 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 ＋ △z] 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 where nodes independently uniform distributed in [zl, z1 ＋ △z] is explained. The analysis is validated by computing the probability of network connectivity and comparing it with the Mont Carlo simu- lation results.
基金partially supported by The National Key Research and Development Program of China(No.2016YFB0200404)National Natural Science Foundation of China(No.61501527,61379157,U1711263)+6 种基金MOE-CMCC Joint Research Fund of China(No.MCM20160104)State’s Key Project of Research and Development Plan(No.2016YFE01229003)the Fundamental Research Funds for the Central Universitiesthe Science,Technology and Innovation Commission of Shenzhen Municipality(JCYJ20160429170032960)Guangdong Science and Technology Project(No.2016B010126003)2016 Major Project of Collaborative Innovation in Guangzhou(No.201604046008)Program of Science and Technology of Guangdong(No.2015B010111001)
文摘Due to high node mobility, stability has been always one of the major concerns of vehicle clustering algorithms in vehicular ad hoc networks. In this paper, we propose a novel clustering algorithm based on the information of routes planned by vehicular navigation systems. In the clustering algorithm, we design a residual route time function to quantitatively calculate the overlapping time among vehicles based on route information, with which a novel clusterhead selection metric is presented. We further design a mechanism of future-clusterhead, which can help avoid message exchanges at intersections and reduce the overhead of cluster maintenance. The simulation results show that, compared with previous works, our clustering algorithm can achieve higher stability and at the same time lower communication cost.
基金partially supported by National Key Research and Development Program of China(2016YFB0200400)National Natural Science Foundation of China(No.61379157)+1 种基金Program of Science and Technology of Guangdong(No.2015B010111001)MOE-CMCC Joint Research Fund of China(No.MCM20160104)
文摘This paper comes up with a SDN Based Vehicle Ad-Hoc On-Demand Routing Protocol(SVAO),which separates the data forwarding layer and network control layer,as in software defined networking(SDN),to enhance data transmission efficiency within vehicle ad-hoc networks(VANETs).The roadside service unit plays the role of local controller and is in charge of selecting vehicles to forward packets within a road segment.All the vehicles state in the road.Correspondingly,a two-level design is used.The global level is distributed and adopts a ranked query scheme to collect vehicle information and determine the road segments along which a message should be forwarded.On the other hand,the local level is in charge of selecting forwarding vehicles in each road segment determined by the global level.We implement two routing algorithms of SVAO,and compare their performance in our simulation.We compare SVAO with popular ad-hoc network routing protocols,including Optimized Link State Routing(OLSR),Dynamic Source Routing(DSR),Destination Sequence Distance Vector(DSDV),and distance-based routing protocol(DB)via simulations.We consider the impact of vehicle density,speed on data transmission rate and average packet delay.The simulation results show that SVAO performs better than the others in large-scale networks or with high vehicle speeds.
文摘随着车联网VANETs(Vehicular Ad hoc Networks)应用日益受到关注,研究者对VANETs路由协议进行了深入研究。为此,首先总结VANETs的特点及应用,再介绍了基于位置的、基于拓扑以及基于广播路由的概念,并着重分析和总结了近期路由协议的核心思想以及特点,此外,还从应用场景、前提条件、虚拟设备要求、电子地图需求、路由恢复策略以及转发模式六个方面对路由协议进行全面比较,最后,展望了VANETs路由技术的未来研究方向。
文摘针对车辆节点快速移动和非均匀分布导致的车联网网络空洞问题,以及空洞节点采用SCF(store carry forward)方法长期携带过时交通信息导致浪费存储资源的问题,提出一种先应式空洞发现策略以及一种限时携带的贪婪前传广播(CGFB,limited time carry and greedy forward broadcast)方法.CGFB结合了GF(greedy forward)算法和SCF算法的优点,可以提高建立路径的成功概率并降低存储消耗.仿真结果表明,当平均邻居节点数大于4时,CGFB算法成功建立路径的概率可达97%以上;相比SCF算法,当平均邻居节点数为2时,可节省90%以上的存储资源.
文摘Logical behavioral arrangements are a class of conventional arrangements to illustrate the happening of incidents in an appropriate and structured approach in vehicular ad hoc network （VANET）. These incidents are characterized as a list of path segments that are passed through by the vehicles for the duration of their journeys from a pre-decided local source to a local destination in a structured manner. A set of proper description illustrating the paths traversed by the vehicles as logical behavioral arrangements is describedin this paper. The data gathering scheme based on secure authentication to gather the data from the vehicles is proposed in this paper. This proposed data gathering scheme based on secure authentication is compared with the existing data gathering schemes by using veins framework and the results of analysis reflect that the proposed scheme outperforms among others. The data collected from the vehicles by the proposed data gathering scheme is stored at distributed road side units （RSUs）. From these collected paths, the common and frequent paths opted by the vehicles in a certain region are determined by using frequent arrangement mining approach. An estimation model is used to decidethe next path and the whole path map opted by the vehicles in unusual situations like accident, jams, or a particular time of day. The proposed scheme will helpthe society in reducing the waiting time in vent of emergency or normal working days.
文摘车载网络(Vehicular ad hoc networks,VANETs)是一种特殊形式的网络,具有节点高速移动、拓扑频繁的变化的特性。这些特性为消息的传播带来挑战。路由机制是实现消息传递的关键因素。地理位置路由被广泛地应用于VANETS,要求节点周期广播beacon消息。然而,节点周期地广播beacon消息,降低了路由性能,特别是在城市区域,由于节点密集,每个节点均广播beacon消息,恶化了路由性能。为此,针对城市环境,提出基于beacon控制的路由协议RPBC(Routing protocol with beacon control)。在RPBC中,并非每个节点广播beacon消息,而设置有效的机制选择部分节点广播,从而降低了beacon冗余,同时,采用最短路径算法,减少数据传输跳数。仿真结果表明,提出的RBPC在分组投递率、端到端传输时延以及路由开销方面均有较好的性能。
文摘Vehicular ad hoc networks （VANETs） that use the IEEE 802.11p communication standard face a number of challenges, not least when it comes to safety messages on the VANET control channel （CCH） where short delay times and reliable delivery are of pri- mary importance. In this paper we propose a vehicular machine-to-machine （VM2M） overlay network that uses Long Term Evolu- tion （LTE） physical random access channel （PRACH） to emulate VANET CCH. The overlay network uses dedicated preambles to separate vehicular traffic from regular LTE traffic and a cartier sense multiple access with collision avoidance （CSMA-CA） layer similar to the one used in IEEE 802.15.4 to avoid the four step handshake and the overhead it incurs. The performance of the pro- posed overlay is evaluated under a wide range of PRACH parameters which conform to the scenarios with high vehicle velocities and large distances between roadside units （RSUs） that may be encountered in rural areas and on highways.
