架构式车联网接纳控制算法的研究

发布时间：2018-08-14 17:21

【摘要】：随着无线网络服务需求的增长,服务类型呈现多样性。多媒体服务具有对延迟时间敏感的特性,它的服务质量(Quality of Service, QoS)对用户的体验具有重要影响。架构式车联网中,车辆节点的高速移动性及资源的有限性导致通信链路维持时间短、丢包率高,严重降低网络性能,影响用户服务质量。因此,如何保障业务服务质量、合理分配有限的网络资源成为架构式车联网主要研究课题之一。接纳控制机制作为资源管理的重要组成部分,是保障用户服务质量的关键技术。本文在分析传统经典接纳控制算法的基础上,结合车联网的特点,提出了基于移动的接纳控制算法(Mobility-based Call Admission Control Algorithm in VANET, MB-CAC)。为了减少控制帧的传输、降低AP负载,MB-CAC算法在接入点(Access Point, AP)广播的beacon帧中携带了网络资源信息。车辆节点接收到beacon帧后,分析获取当前网络资源的使用情况,初步判断其业务请求是否能够被AP接纳。如果业务请求可以被AP接纳,车辆节点则发送业务请求控制帧,否则,直接放弃业务请求。为了保证高优先级的业务请求优先被AP接纳,MB-CAC算法通过设定信道空闲等待时间AIFS和竞争窗口大小来进行业务区分,从而保证高优先级业务优先访问信道。当AP接收到车辆节点的业务请求时,根据业务开启时间进行分类。如果请求业务是切换业务,则AP执行切换业务接纳原则,否则执行新请求业务接纳原则。在切换业务接纳原则中,为保证切换业务优先级,AP根据相邻AP业务接纳率及切换业务到达概率,预留一定的带宽资源用于切换业务的接纳。在新请求业务接纳原则中,根据新请求业务接纳数量对切换业务的影响,设定新请求业务接纳阈值K。本文分别从数学分析和实验仿真的角度,对MB-CAC算法的切换业务丢失率、新请求业务阻塞率、信道利用率、吞吐量四个性能参数进行了分析。数学分析和仿真实验结果表明,MB-CAC算法降低了切换业务丢失率和新请求业务阻塞率,提高了信道利用率和网络吞吐量。
[Abstract]:With the increasing demand of wireless network services, the types of services are diversified. Multimedia service is sensitive to delay time, and its quality of service (Quality of Service, QoS) has an important impact on the user's experience. The high speed mobility of vehicle nodes and the limitation of resources lead to short communication link maintenance time and high packet loss rate, which seriously reduce the network performance and affect the quality of service of users. Therefore, how to guarantee the service quality and allocate the limited network resources rationally becomes one of the main research topics of the frame vehicle networking. As an important part of resource management, admission control mechanism is the key technology to guarantee the service quality of users. Based on the analysis of the classical admission control algorithm and the characteristics of vehicle networking, a mobile based admission control algorithm (Mobility-based Call Admission Control Algorithm in VANET, MB-CAC) is proposed in this paper. In order to reduce the transmission of the control frame, the AP load MB-CAC algorithm carries the network resource information in the beacon frame broadcast by the access point (Access Point, AP). After receiving the beacon frame, the vehicle node analyzes the usage of the current network resources and preliminarily determines whether the traffic request can be accepted by the AP. If the service request can be accepted by the AP, the vehicle node sends the service request control frame, otherwise, the traffic request is abandoned directly. In order to ensure that high priority traffic requests are first accepted by AP MB-CAC algorithm distinguishes traffic by setting channel idle waiting time (AIFS) and competing window size so as to ensure high priority services to access the channel first. When the AP receives a service request from a vehicle node, it classifies according to the service opening time. If the request service is a handoff service, the AP executes the handoff service admission policy, otherwise the new request service admission principle is executed. In the handoff admission principle, in order to ensure the handoff service priority AP, according to the admission rate of adjacent AP services and the arrival probability of handoff services, a certain bandwidth resource is reserved for the admission of handoff services. In the new request service admission principle, the new request service admission threshold K is set according to the effect of the new request service admission number on the handoff service. From the point of view of mathematical analysis and experimental simulation, this paper analyzes four performance parameters of MB-CAC algorithm, such as handoff traffic loss rate, new request traffic blocking rate, channel utilization rate and throughput. The results of mathematical analysis and simulation experiments show that the MB-CAC algorithm reduces the loss rate of handoff traffic and the blocking rate of new request traffic and improves the channel utilization and network throughput.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U495;TN929.5;TP391.44

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