车联网中的数据聚集研究

发布时间：2018-01-26 08:33

本文关键词： 车联网移动感知网络数据聚集延迟精度　出处：《哈尔滨工业大学》2015年博士论文　论文类型：学位论文

【摘要】：随着无线通信技术、信息传感技术及自动控制技术的快速发展,物联网被广泛应用于农业、交通、物流、家居等领域。作为物联网在交通领域的重要应用,车联网为智能交通的实现提供了技术支持平台。智能交通的许多应用需要收集和分发大量实时信息,但车辆的移动性使车联网中收发信息所需要的通信资源频繁变化,加之这些通信资源又非常有限,因此车联网中的数据收集和分发是一项极具挑战的工作。为了减少数据收发过程中传输数据量,研究者们引入了数据聚集技术,该技术已成为车联网领域中倍受学术界关注的研究热点。虽然数据聚集可以节省数据传输中信带资源的消耗,但也会影响数据的时延和精度。聚集数据的时延和精度直接影响车联网上诸多应用的正确性和有效性。本文研究车联网的数据聚集问题,主要工作及其成果包括以下几个方面。首先,研究了时延约束的单信道车联网数据聚集问题。车联网上许多应用对感知数据的时延有很高要求,但现有研究无法使得聚集数满足时延要求,且没有有效利用连通链路信息使得时限内聚集信息量较少。时延往往是由无线冲突引起的,如果能合理规划传输时刻有效避免冲突,即可实现时延约束的聚集优化。因此,本文提出了时延约束的单信道车联网数据聚集问题,即规划无冲突的传输时刻以优化聚集信息量。给出了该问题的形式化定义,并证明其是NP难的。本文提出了一种时延约束的优化聚集信息量算法。该算法的核心是如何避免数据传输过程中的无线冲突。无线冲突可分为两类,一类是多节点同时向同一节点发送数据引起的冲突,被称为直接冲突;另一类是节点在接收数据时通信范围内存在其他节点干扰引起的冲突,被称为间接冲突。为避免直接冲突,本文利用动态规划技术在候选时刻集上规划节点的聚集传输时刻。为避免间接冲突,本文提出了基于匹配和独立集的候选时刻集过滤技术。利用真实出租车轨迹数据集进行了大量的实验。实验结果表明本文所提出的算法在同一时延界内比现有的算法在数据收集率上提高了近20%,在平均传输数据量上减少至1/3,在平均时延上更加稳定。其次,研究了时延约束的多信道车联网数据聚集问题。为了提高频谱利用率,车联网标准协议栈中引入多信道机制。与单信道不同,多信道采用频分复用减少了无线冲突,但需要额外解决信道分配问题。因此,本文提出了时延约束的多信道车联网数据聚集规划算法。该算法的基本思想是利用多信道资源避免间接冲突。其核心是规划节点的路由使得节点的间接冲突数小于信道个数k进而实现冲突节点采用不同信道规避间接冲突。本文首先基于贪心思想构建k约束优化聚集路由树规划节点的路由,然后利用动态规划技术规划节点的传输时刻和传输信道。该时刻规划可以得到最优解。最后在真实轨迹数据集和模拟轨迹数据集上对本文提出的算法进行了大量实验。结果表明本文的算法在数据收集率上比现有算法提高了25%,达到95%以上;在聚集效率上比现有算法提高了3倍以上。再次,研究了单一精度约束的车联网数据聚集问题。与时延约束不同,精度约束的数据聚集优化核心是在满足精度要求前提下利用数据的相关性降低传输数据量。现有研究引入压缩感知技术高效地压缩数据量同时保证恢复的数据满足精度要求,但压缩感知技术的实现需要满足有限等距约束条件,这意味着数据要依据特定方式进行聚集。由于车联网上的数据是由移动车辆携带,数据的聚集方式受到车辆移动的限制。现有研究采用人工引入车辆控制移动路线解决这一难题,但需要消耗大量资源且没有利用车联网已有的无线通信资源。因此,本文提出了车联网上基于压缩感知的精度约束数据聚集传输协议。该协议利用车之间的无线通信动态调整移动车辆携带的数据实现了满足压缩感知要求的数据聚集,进而实现了精度约束的车联网数据聚集传输。实验结果表明本文所提出的方法利用50%的数据量即可得到满足精度要求的聚集数据。最后,研究了多精度约束的车联网数据聚集问题。由于车联网中动态可用带宽资源有限,实时导航系统在收集实时路况信息时要在满足多用户的导航请求前提下降低传输数据量。导航请求的不均匀分布使得部分路段的数据精度影响较多用户导航响应的准确性。聚集数据的精度决定了传输数据量。各路段基于各自的精度要求进行数据聚集可以实现在满足多用户的导航请求前提下有效地降低传输数据量。与单精度不同,多精度的数据聚集需要获取多精度要求,分发多精度聚集请求,以及多精度约束的数据聚集传输。因此,本文提出了车联网上多精度约束的数据聚集传输协议。该协议首先通过求解精度抽取的几何规划问题得到各路段聚集数据的精度要求,然后构造各路段的带有精度要求的数据聚集请求,最后根据各精度请求进行数据聚集传输实现多精度约束的数据聚集。模拟实验结果表明该协议的数据收集率达到80%左右,比朴素方法提高了20%,消耗的带宽资源为聚集数据量的2.5倍,比朴素方法降低了1/3以上。
[Abstract]:With the development of wireless communication technology, information sensing technology and rapid development of automatic control technology, networking is widely used in agriculture, transportation, logistics, and other fields. Home Furnishing things as an important application in the field of transportation, provides the technical support for the realization of intelligent transportation platform vehicle networking. Intelligent transportation and many applications need to collect and the distribution of a large number of real-time information, but the vehicle mobility makes vehicle communication resources necessary to send and receive information of the network changes frequently, and these communication resources are very limited, so the car networking in data collection and distribution is a very challenging work. In order to reduce the amount of data transmission in the process of sending and receiving data, researchers have introduced the data aggregation technology, the technology has become a vehicle networking in the field of research has been the focus of academic attention. Although the data gathered can save the data transmission with citic resources consumption, but Will also affect the delay and accuracy of data. The correctness and validity of the aggregation delay and accuracy directly affects the data car intranet for many applications. This paper studies the data aggregation of car networking, the main work and achievements are as follows. First, the single channel data of car networking delay constraint aggregation problem. Time delay of car combined application of many online sensing data have high requirements, but the existing research cannot satisfy the delay requirements of the aggregation number, and there is no effective use of link connectivity information makes less information gathered within the time limit. The delay is often caused by wireless conflict, if properly planning transmission time to effectively avoid conflict and realize the optimization of aggregation delay constraint. You can. Therefore, this article presents the problems of single channel data aggregation vehicle network delay constraints, namely the conflict free transmission time planning to optimize the gathered information. The formal definition of the problem is given, and prove that it is NP hard. This paper puts forward the optimization of a delay constrained information aggregation algorithm. The core of the algorithm is how to avoid the conflicts in the process of wireless data transmission. The wireless conflict can be divided into two categories, one is the conflict caused by sending data to multiple nodes the same node at the same time, known as direct conflict; the other is the node in the other node interference caused by the conflict of communication exist within the range of receiving data, known as indirect conflict. In order to avoid direct conflict, the transmission time aggregation node in the candidate set planning time using dynamic programming technology. In order to avoid indirect conflict in this paper, the candidate matching and moment independent sets of sets based on filtering technology. Using real taxi trajectory data sets for the experiments. The experimental results show that this proposed algorithm at the same time. Compared with the existing algorithm collection rate increased nearly 20% in the data, the average amount of data transmission to reduce 1/3, more stable in average delay. Secondly, multi channel data of car networking delay constraint aggregation problem. In order to improve the spectrum utilization, car networking into multi-channel mechanism in different standard protocol stack. With a single channel, multi channel using frequency division multiplexing to reduce wireless conflict, but need to solve the channel assignment problem. Therefore, this paper proposes a multi channel vehicle networking data delay constraint aggregation programming algorithm. The basic idea of the algorithm is the use of multi channel resources to avoid indirect conflict. Its core is the number of nodes makes routing planning indirect conflict node is less than the channel number k so as to realize the conflict between nodes by different channels to avoid indirect conflicts. Firstly, based on the greedy idea to construct the optimal aggregation routing tree node K constraint programming The route, then using the dynamic programming technology planning node transmission time and transmission channel. The time planning can get the optimal solution. Finally, in the real trajectory data set and simulated trajectory data sets for the algorithm proposed in this paper. A large number of experimental results show that this algorithm in the data collection rate than the existing algorithm increased by 25%. More than 95%; in the aggregation efficiency than the existing algorithm increases more than 3 times. Once again, the car networking data of single precision constraint aggregation problem. With delay constraint, constraint optimization precision data aggregation is the core in meet the precision request under the premise of using the correlation of data to reduce the amount of data transmission. The existing research into high efficiency to reduce the amount of data at the same time to ensure the recovery of data meet the accuracy requirements of compressed sensing technology, but the realization of compressed sensing technology to meet the needs of the restricted isometry constraints, this means A data according to the specific way of gathering. Because the car Internet data is carried by the mobile vehicle, the data gathered by the mobile vehicle restrictions. The existing research into vehicle control using artificial mobile route to solve this problem, but requires wireless communication resources consume a lot of resources without the help of the car networking. Therefore, this paper presents the accuracy of car networking constraints based on compressed sensing data transmission protocol. The protocol uses aggregation vehicle wireless communications between mobile vehicle dynamic adjustment carry data can meet the requirements of the compressed sensing data aggregation, and then realizes the transmission accuracy of aggregation constraints of car networking data. Experimental results show that the method proposed in this paper are met gather data accuracy using the data quantity to 50%. Finally, car networking data on multiple precision constraint aggregation problem. Because the car network dynamic available bandwidth is limited, real-time navigation system to reduce the amount of data transmission in the premise to meet the user's navigation request in the collection of real-time traffic information. The uneven distribution of the navigation request sections of the data affects the accuracy of user navigation more response accuracy. Aggregate data determines the accuracy of the amount of data transmission. Each section of their precision requirements for data aggregation can effectively reduce the amount of data transmission in the premise to meet the user's navigation request. Based on the different with single precision, multi precision data aggregation needs to get more precision, distributed multi precision aggregation request, and the accuracy of constrained data aggregation transmission. Therefore, this paper puts forward multi precision constrained data aggregation protocol. This protocol has car networking sections first through the geometric programming problem solving precision extraction The aggregation data accuracy requirements, and then construct the sections with the accuracy requirements of the data aggregation request, according to the request of data collection and transmission accuracy for multi precision constrained data aggregation. The simulation results show that the protocol of the data collection rate reached 80%, 20% higher than the naive method, consumption of bandwidth resources for 2.5 times the amount of data aggregation, reduce the 1/3 more than the naive method.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U495;TP391.44;TN929.5

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