车联网环境下基于可靠接入的高效数据传输机制研究

发布时间：2018-05-23 20:35

本文选题：车联网 + 实时定位　；参考：《北京邮电大学》2014年博士论文

【摘要】：车联网是一种基于人、车、环境协同的融合网络系统,其通过信息技术,对人、车、网络通信及道路交通基础设施等环境元素的静态／动态信息进行感知、认知和计算,以解决车联网中的协同通信、资源管理和信息服务的可计算性、可扩展性和可持续性问题,从而最终实现人、车、环境的深度融合,以丰富个人汽车生活,提高交通出行效率,改善城市服务水平,降低社会运行成本。作为车联网协同通信的一个重要研究方向,数据传输主要通过异构无线网络进行人、车、环境(道路、传感设备、网络等)之间的数据传输。然而由于车联网中网络环境的动态多变、物理环境的复杂多样、信息(空间)环境中数据的海量性与稀疏性并存,使得一些传统的数据传输技术并不能对车联网中的数据传输提供很好的支持,因此,迫切需要一种数据传输方法用于保障车联网环境下数据传输的高效性、可靠性／稳定性。所以,如何在车联网环境下,以一种有效的机制或方法保障数据传输的可靠性和高效性,已成为车联网协同通信技术中一个研究热点。虽然国内外的研究工作取得了一定进展,但在保障车联网环境下数据传输的可靠性和高效性研究方面仍然存在不足： 1)尽管面向数据传输的已有车辆定位技术能提高网络接入和分簇路由的效率,但当前车辆定位技术过于依赖GPS,定位方式缺乏灵活性,不能充分发挥各种定位技术在不同环境下的定位优势。 2)面向数据传输的网间切换策略能够为数据传输提供网络支持,然而单一的网间切换策略既不能满足车辆的切换要求,也没有体现用户对网络的具体需求。已有的切换策略对网络相关状态和终端运动状态多条件下的考虑不充分,并且忽略了车辆的移动性和终端业务的变更对网络质量产生的负面影响,导致网络稳定性急剧下降。 3)车联网中接入点的安全性通常能够为数据传输提供可靠性保障,但由于车联网的开放性,众多的陌生节点,导致现有的安全策略难以有效支持大规模、高移动性的节点数量,这使得车联网的安全接入和数据传输的可靠性难以得到保障。 4)车联网中多径路由在节点缓存能力、带宽以及长度上各异,导致数据包次序混乱,重传失效,而低效率的重传将导致网络容量的浪费,增加了端到端时延,这将在很大程度上影响数据传输的效率,尤其较小的数据误差被大幅度的放大,将进一步降低数据传输的效率。为此,针对上述问题,本论文以车联网环境中的网络接入为立足点,以实时定位、垂直切换、安全接入等研究为突破点,以分簇协同通信为呈现点,围绕车联网环境中的高效数据传输机制进行了深入研究,取得了以下研究成果： 1)提出基于可变重要度的车辆实时定位方法。针对多径衰落,阴影效应,定位基站部署不足等影响导致的定位精确度低下问题,提出了一种基于可变重要度的车辆定位方法。该方法首先,通过定位技术相应的误差度确定位置的覆盖区域,然后,根据知识库下的重要度方法分析计算出每个定位技术位置域的重要度,并以重要度的变化作为反馈来优化定位技术的误差度,最后,以位置域的重要度作为复合位置域的权值,加权平均出目标位置。实验结果表明,该方法能够在满足定位实时性的同时,提高定位的准确度。 2)提出基于认知自选择决策树的垂直切换方法。针对网络选择多样性导致的网络稳定性和服务质量低下的问题,提出了一种基于认知自选择决策树的垂直切换方法。该方法通过车辆位置信息构建了多属性的车辆切换概率分布,并根据车辆用户对网络的偏好类型,提出了用户自选择切换决策树算法。实验结果表明,该方法能有效地满足车辆在异构无线网络间的切换和服质量需求。 3)提出了一种车联网接入安全认证方法。针对非安全接入点导致的车联网数据传输可靠性下降的问题,提出一种车联网多级安全认证方法。该方法首先采用基于哈希加密认证的RFID电子车牌进行车辆的身份认证,在确认车辆身份合法的基础上对车辆进行安全信任评估认证。安全信任评估包含直接信任评估和间接信任评估,直接信任评估主要通过服务端参考历史安全度进行信任评估,间接信任评估则通过组网内节点推荐信任进行信任评估。安全认证方法提供了身份认证,接入组网认证以及组网接纳认证。仿真实验表明所提的信任评估方法能有效地对非安全车辆节点进行区分,保障接入节点的安全性。 4)提出了一种基于车联网分簇路由的多径传输方法。针对车联网拓扑变化快,多径干扰导致数据传输效率低下的问题,提出一种基于分簇协同的数据传输方法,该方法根据车辆运动趋势建立车联网分簇模型,在分簇的基础上根据有向图寻路方式发现簇与簇之间的路径,提高了多径路由的效率和网络的稳定性。在此基础上为提高数据传输效率,提出了基于网络编码的数据传输算法,对数据进行编码,重编码和解码操作。仿真实验表明,该方法在提高分簇稳定性的基础上提高了多径路由下数据传输的效率。
[Abstract]:The vehicle network is a kind of integrated network system based on human, car and environment. It can perceive, recognize and calculate the static / dynamic information of environment elements such as human, car, network communication and road traffic infrastructure, which can solve the computability and extensibility of resource management and information service through information technology. And sustainability issues, in order to achieve the ultimate integration of people, cars and environment, to enrich individual car life, improve transportation efficiency, improve the service level of the city, and reduce the cost of social operation.
As an important research direction in the collaborative communication of vehicle networking, data transmission is transmitted mainly through heterogeneous wireless networks for human, vehicle, environment (road, sensor equipment, network, etc.). However, because of the dynamic changes in the network environment in the network of vehicles, the complexity of the physical environment and the mass and dilute of the data in the information (space) environment The coexistence of sparse data makes some traditional data transmission techniques do not provide good support for data transmission in the network of vehicles. Therefore, a data transmission method is urgently needed to ensure the efficiency, reliability and stability of data transmission under the environment of the vehicle network. To ensure the reliability and efficiency of data transmission, the method has become a research hotspot in the cooperative communication technology of vehicle networking.
Although some progress has been made in the research work at home and abroad, there are still shortcomings in the research of reliability and efficiency of data transmission under the network environment.
1) although the existing vehicle positioning technology facing data transmission can improve the efficiency of network access and cluster routing, the current vehicle positioning technology is too dependent on GPS, and the positioning mode is lack of flexibility, and it can not give full play to the positioning advantages of various positioning technologies under different environments.
2) the inter network switching strategy for data transmission can provide network support for data transmission. However, a single Internet switching strategy can neither meet the switching requirements of the vehicle nor reflect the specific requirements of the user on the network. The existing handover strategy is not fully considered for the multiple conditions of the network related state and the terminal movement state. Ignoring the negative effects of vehicle mobility and terminal business changes on network quality, the network stability has dropped dramatically.
3) the security of access points in the vehicle network usually provides reliability guarantee for data transmission. However, because of the openness of the Internet of vehicles, many unfamiliar nodes, resulting in the existing security strategies, are difficult to effectively support large scale and high mobility nodes, which makes the reliability of the safe access to the network and the reliability of the data transmission difficult to be guaranteed.
4) the multipath routing in the Internet of vehicles varies with the node caching capability, bandwidth and length, which leads to the chaotic sequence of data packets and retransmission failure, and the low efficiency retransmission will lead to the waste of network capacity and increase the end to end delay. This will greatly affect the efficiency of data transmission, especially the small data error is greatly enlarged. Further reduce the efficiency of data transmission.
Therefore, in view of the above problems, this paper takes the network access in the environment of the car network as the foothold, taking real-time positioning, vertical handover and secure access as the breakthrough point, taking cluster cooperative communication as the presentation point, focusing on the efficient data transmission mechanism in the vehicle network environment, and obtains the following research results:
1) a vehicle real-time positioning method based on variable importance is proposed. A vehicle location method based on variable importance is proposed to solve the problem of low positioning accuracy caused by the influence of multi-path fading, shadow effect and the lack of location of the base station. This method first determines the coverage area of the position by the corresponding error degree of the positioning technique. Then, according to the importance degree method under the knowledge base, the importance of each location technology position domain is analyzed and calculated, and the error degree of the positioning technology is optimized by the change of the importance degree. Finally, the importance of the position domain is taken as the weight value of the compound location domain, and the weighted average of the target position is weighted. The experimental results show that the method can be full. Foot positioning is real-time while improving positioning accuracy.
2) a vertical handoff method based on cognitive self selection decision tree is proposed. A vertical handoff method based on cognitive self selection decision tree is proposed to solve the problem of network stability and low service quality caused by network selection diversity. This method constructs a multi attribute vehicle switching probability distribution through vehicle location information, and it is based on the method of vehicle location information. The user self selection switching decision tree algorithm is proposed by the user's preference type for the network. The experimental results show that the method can effectively meet the switching and service quality requirements of vehicles in heterogeneous wireless networks.
3) a security authentication method for vehicle networking access is proposed. A multilevel security authentication method for vehicle networking is proposed to reduce the reliability of the vehicle network data transmission caused by unsafe access points. This method first uses the RFID electronic license plate based on Hash encryption authentication to authenticated the vehicle, and confirms the legal status of the vehicle. On the basis of the security trust assessment authentication of vehicles, the security trust assessment includes direct trust assessment and indirect trust assessment, and direct trust evaluation mainly evaluates the trust through the service end reference history security, and the indirect trust evaluation is evaluated through the recommendation of the nodes in the network. The security authentication method provides the identity. The simulation experiment shows that the proposed trust evaluation method can effectively distinguish the non safe vehicle nodes and ensure the security of the access nodes.
4) a multipath transmission method based on cluster routing is proposed. In view of the fast change of topology and the low efficiency of multipath interference, a data transmission method based on cluster coordination is proposed. The method is based on the trend of vehicle movement to establish the cluster model of the vehicle network, and based on the clustering, the directed graph is based on the clustering. The path finding between clusters and clusters is found to improve the efficiency of multipath routing and the stability of the network. On the basis of this, a data transmission algorithm based on network coding is proposed to improve the efficiency of data transmission, and the data are coded, encoded and decoded. The simulation experiment shows that the method is based on improving the stability of clustering. The efficiency of data transmission under multipath routing is improved.
【学位授予单位】：北京邮电大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TP391.44;TN929.5

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