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分布式交通态势感知与传播方法

发布时间:2018-03-01 22:32

  本文关键词: 车辆自组织网络 交通态势感知 广播方法 分布式传输 出处:《电子科技大学》2015年博士论文 论文类型:学位论文


【摘要】:随着经济的迅速发展,私家车保有量急剧增长,虽然城市交通路网也得到了极大提升,但汽车保有量远远超过了路网的承载能力。现有城市智能交通系统的局部信息采集和集中处理与分发机制,已不能适应交通流的大规模聚集和高突发性,交通指挥控制严重滞后,高峰期仍需大量人工干预,无法从根本上缓解城市交通拥堵问题。为此,急需突破现有智能交通系统框架,建设一种新型智能交通控制系统,及时获得并发布高实时性交通态势给所辖或邻居区域,为车辆主动进行拥堵避免和分流提供依据,从而在有效缓解交通拥堵的同时极大地提高道路网络的运行效率。围绕这一课题,论文所在项目组提出了一种基于车辆间通信的分布式智能交通系统框架,其中车辆既是交通态势的感知节点、态势信息的传输(中继)节点,又是态势信息的接收节点和最终受益者。其主要关键技术包括车辆定位、交通态势信息获取/融合/传输、交通流大数据分析及其应用(如实时交通地图更新与发布等)。本论文先给出分布式智能交通系统架构,然后针对交通态势信息感知与传输技术进行研究,具体包括:第一,研究路面上车辆定位、群移动速度获取和交通状态感知方法和技术。首先,针对现有GPS等车辆定位方法不能定位到车辆所在车道、信号易受遮挡等缺陷,提出了一种基于RFID的路面移动车辆主动定位方法(RAVP,RFID based Active Vehicle Positioning),并对RFID标签的安装部署方案、定位性能和成本等进行了详细分析。其次,考虑群移动速度是表征车流的重要参数之一,给出了一种基于聚簇的群速度感知方法。最后,当获取了准确的位置信息和群移动速度后,结合模糊逻辑理论中的模糊映射函数关系得到交通拥堵等级。提出了一种基于VANETs的交通畅通-拥堵状态感知方法(Tra SD-VANET,Traffic Situation Detection method using Vehicular Ad-hoc NETworks)。在车辆密度不同的交通场景中,把Tra SD-VANET与现有方法进行仿真对比,Tra SD-VANET方法不仅可以动态地感知交通状态,而且具有较高的准确度,该感知结果用于交通疏导,可提高车辆的平均行驶速度,减少停等车辆数目,缩短等待时间,提高了路网效率。第二,节点非均匀分布和高速移动使VANETs具有拓扑捷变性、网络节点突发性地大规模聚集性和稀疏节点密度时的网络连接通断性等。针对VANETs的网络特性带来的广播冲突、网络空洞等问题,分析了在VANETs中传播信息时的数据包成功投递率和多跳连通性。首先,为分析2-D VANETs中广播的数据包成功接收率,建立了十字路口场景,分析了隐藏终端、并发节点、广播覆盖范围、载波侦听范围、邻居的干扰范围等因素对数据包接收的影响,推导了数据包的成功接收概率与上述因素间的关系式,仿真验证了分析结论。该结论为后续多跳广播的性能评估及应用需求提供了理论依据。其次,从新的视角分析多跳传输的连通性,研究了网络空洞在VANETs中的产生概率和分布率,给出了采用SCF路由算法解决网络空洞问题时数据包成功传输的时间延迟表达式,并分析了时间延迟在不同车辆环境下的分布,为所提广播方法设定携带时长提供了参考。第三,为了应对信息传播过程中面临的广播冲突、网络过载、网络空洞等问题,提出三种传播方法。首先,针对网络节点的快速移动带来的邻居信息快速失效问题,以及高节点密度环境下频繁地广播信标带来的广播冲突和网络过载问题,提出了一种自适应调节信标广播间隔的方法(SDMB,Self-Decision-Making Beaconing)。在该方法中,节点根据自身及邻居节点的活跃度,确定信标广播的时间间隔,以改善网络性能。结果表明,与IEEE802.11p的WAVE模型中采用的固定速率广播beacon的方法相比,SDMB方法有较高的信标广播成功率和较低的网络负载率。其次,针对由车辆节点的高速移动和非均匀分布导致的网络空洞问题,提出了一种先应式网络空洞发现策略,在此基础上提出时间受限的携带贪婪前传方法(CGFB,Carry Greedy Forward Broadcast)。该方法中的空洞发现策略是依据精确的位置信息建立邻居排序表,通过查询表格中的邻居存无和节点间的几何关系发现网络空洞,再通过携带贪婪前传,有效解决由网络空洞导致的链路中断问题,提高了成功传输数据包的概率。同时,根据网络空洞的分布概率设定携带时长,以降低对缓存资源的消耗。结果表明,CGFB算法在建立连通路径的成功率和节省存储资源方面优于GF和SCF算法。最后,针对事故信息的影响特点以及特定目标区域对信息广播的需求,提出了一种空时受限的交通态势信息传播方法(STLIB,Space-Time Limited Infection Broadcast)。该方法在限定的时间和目标区域内及时广播交通信息,告知后续车辆及时分流绕避交通事件/事故发生路段。结果表明,使用STLIB方法后,车辆排队长度显著缩短,有效缓解了交通拥堵。
[Abstract]:With the rapid development of economy, the rapid growth of private cars, although the city traffic has been greatly improved, but the cars far exceeded the carrying capacity of the road network. The existing city intelligent transportation system local information collection and centralized processing and distribution mechanism, already can not adapt to the traffic flow in large-scale aggregation and bursty. Traffic control is seriously lagging behind, the peak still needs a lot of manual intervention, can not alleviate the city traffic congestion problem fundamentally. Therefore, the urgent need to break the existing framework of intelligent transportation systems, the construction of a new intelligent traffic control system, timely access to and release the high real-time traffic situation to the jurisdiction or neighborhood, for vehicle active congestion to avoid the shunt and provide the basis, thus greatly improve the efficiency of the road network at the same time effectively alleviate traffic congestion. Around this topic, the The project team proposed a framework of distributed intelligent transportation system based on inter vehicle communication, the vehicle is aware node traffic situation, transmission state information (relay) node, and is state information receiving node and the ultimate beneficiaries. Its key techniques include vehicle location, traffic situation information acquisition / fusion / transmission traffic flow, big data analysis and Its Applications (such as real-time traffic map updating and Publishing). This paper first presents a distributed intelligent transportation system architecture, and then according to the traffic situation information sensing and transmission technology research, including: first, vehicle positioning on the road, moving speed and traffic state group gets perception method and technology. First, according to the existing GPS vehicle positioning method cannot navigate to where the vehicle lane, the signal is susceptible to occlusion and other defects, proposed a road mobile vehicle based on RFID Active positioning method (RAVP, RFID based Active Vehicle Positioning), and install the deployment scheme of the RFID tag, the positioning performance and cost are analyzed in detail. Secondly, considering the group moving speed is one of the important parameters of traffic characterization, presents a group velocity sensing method based on clustering. Finally, when the the position information and the moving speed of accurate group, combined with the fuzzy mapping function relationship logic theory in the traffic congestion level. Proposed a method for congestion aware VANETs traffic - based (Tra SD-VANET, Traffic Situation Detection method using Vehicular Ad-hoc NETworks). The density of vehicles in different traffic scenarios, the Tra SD-VANET simulation comparison with the existing methods, Tra SD-VANET method can not only dynamically perceive the traffic state, but also has high accuracy, the sensing results For traffic, the average speed of vehicles can be enhanced, and reduce the number of vehicles, shorten the waiting time, improve the efficiency of road network. Second, non uniform node distribution and high speed mobile VANETs network node topology with Czech degeneration, sudden large-scale aggregation and sparse node density when the network connection continuity. According to the characteristics of VANETs radio network conflict caused by network hole. Analysis of the dissemination of information in VANETs data packet delivery success rate and multi hop connectivity. First of all, for the analysis of 2-D broadcasting in VANETs packet reception success rate, a crossroads scene, analyzes the hidden terminal, concurrent node broadcast the coverage, the carrier sensing range, the range of interference factors of neighbor effect on data packet reception, successful packet reception probability and the above factors were deduced, simulation The conclusions of the analysis. The conclusion provides a theoretical basis for the performance evaluation and application of the needs of the subsequent multi hop broadcast. Secondly, connectivity analysis of multi hop transmission from a new perspective, studies the network empty in VANETs probability and distribution rate, given the packet transmission time delay network problem the expression of SCF routing algorithm, and analyzes the time delay distribution in different vehicle environment, for the broadcast setting method when carrying long reference. Third, in order to cope with the broadcast conflict in the process of information transmission, network overload, network problems such as empty, put forward three kinds of communication methods. Firstly, the problem of fast according to the rapid failure of the mobile network node from the neighbor information, and high node density environment frequently brings conflict and radio broadcasts a beacon network overload problem, we propose an adaptive Method of regulating beacon broadcast interval (SDMB, Self-Decision-Making, Beaconing). In this method, node and neighbor nodes according to their activity, determine the beacon broadcast time interval, in order to improve the network performance. The results show that compared with the fixed rate of broadcast beacon using the WAVE model in IEEE802.11p, the SDMB method has the load rate radio beacon high success rate and low network. Secondly, according to the vehicle by the high-speed mobile nodes and non uniform distribution caused by network hole problem, proposed a proactive network hole discovery strategy based on time constrained greedy methods carry prequel (CGFB, Carry Greedy Forward Broadcast). In the method of empty found method is on the basis of accurate location information of neighbor table, through the query form the neighbor nodes and no deposit geometry relationship found in the network Empty, then carry the greedy prequel, effectively solve the problem of interrupt by the link network empty result, improve the probability of successful packet transmission. At the same time, according to the probability distribution network empty set carry long, in order to reduce the cache resource consumption. The results show that the CGFB algorithm in the establishment of the communication path and the success rate of saving the storage resource is better than GF and SCF algorithm. Finally, the influence of characteristics of accident information and target specific areas of demand for information broadcasting, the traffic situation information dissemination method of space-time constrained (STLIB, Space-Time Limited Infection Broadcast). This method in time and the target area in the limited time radio traffic information. Inform the following vehicle timely triage around to avoid the traffic incident / accident road. The results show that using the STLIB method, the vehicle queue length was significantly shortened, effectively alleviate traffic Traffic jam.

【学位授予单位】:电子科技大学
【学位级别】:博士
【学位授予年份】:2015
【分类号】:U491


本文编号:1553904

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