车载自组织网络信息分发机制的研究

发布时间：2018-01-13 22:14

本文关键词：车载自组织网络信息分发机制的研究　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着车辆数目的不断增加,街道日益拥挤,行车安全不能得到有效保证,环境和能源供不应求等问题亟需解决。这些尖锐的问题给国家带来不少经济损失。VANET的概念在不断尝试和探索的过程中诞生。它针对的是以车辆为节点的通信网络,与传统的Ad Hoc网络有很多不一样的特征。VANET中车辆运动速度较快,网络连接关系因时因地实时变化,节点密度分布不一,而且无线通信很容易受到高楼大厦等障碍物的阻挡。传统的路由和MAC协议不再适用于VANET,而它们直接影响报文投递率、时延、网络吞吐量等通信指标。因此,对路由和多信道MAC协议深入的研究势在必行。本论文在第二章中概述了VANET路由当前的研究进展,分析了不同类型路由的优缺点。本文提出GPCR-D的路由,与传统的基于位置的路由不同的是:它考虑了VANET的节点密度。GPCR-D能够动态判定节点密度,并且实时建立和维护节点密度大的局部区域。在节点密度大的局部区域内,车辆移动速度较慢,拓扑结构相对稳定,采用最短路算法进行路由;处于局部区域以外的节点仍然采用贪婪思想转发。同时,本论文改进了GPCR中的“空洞问题”和恢复策略,右手定所选出的下一跳路由很有可能朝着远离目的节点的方向转发,改进后的恢复策略结合了车辆的位置与角度。在需要Qos保证的VANET环境下,单一信道竞争的MAC协议面临非常严重的挑战,它已经不能满足网络容量和传输速率更高的需求。多信道的MAC协议应用而生。本论文提出考虑了节点密度和服务流量的多信道MAC协议,在保证通信性能的前提下,尽可能少的减少切换次数。节点密度较大,并且服务信息流量较大的节点划分为α模式;当节点密度较大,但服务信息流量较小时划分为β模式;其余情况的节点划分为γ模式。根据不同模式的特点,采用不同的报文发送模式,并且给出三种模式之间的判定和切换方法。对于α模式,给出动态调整周期数的PID算法和自适应算法。在保证安全信息的可靠传输条件下,对SCH信道进行合理分配,保证安全信息的发送,尽可能地满足用户的服务需求,提高数据带宽。最后,本论文在OMNET++平台上,以SUMO为交通模拟器。选用Veins这款开源的车辆间通信模拟仿真框架,仿真了GPCR-D和多信道MAC协议。实验结果表明,数据包投递率和传输时延都得到了改善,具有较好的通信性能。
[Abstract]:With the increasing number of vehicles and increasingly crowded streets, traffic safety can not be effectively guaranteed. The problems of environment and energy shortage need to be solved urgently. These sharp problems have brought a lot of economic loss to the country. The concept of VANET has been born in the process of constantly trying and exploring. It is aimed at the vehicle as the node. The communications network. Compared with the traditional Ad Hoc network, there are many different characteristics. The speed of vehicle moving in VANET is relatively fast, the connection relation of the network changes in real time, and the density distribution of nodes is different. And wireless communication is easily blocked by obstacles such as high-rise buildings. Traditional routing and MAC protocols are no longer applicable to VANET.However, they directly affect the message delivery rate and delay. Therefore, it is imperative to study the routing and multi-channel MAC protocols. In the second chapter, this paper summarizes the current research progress of VANET routing. The advantages and disadvantages of different types of routing are analyzed. The routing of GPCR-D is proposed in this paper. Different from the traditional location-based routing, it considers the node density of VANET. GPCR-D can dynamically determine the node density. In the local area with high node density, the speed of vehicle moving is slow and the topology is relatively stable, so the shortest path algorithm is used to route. The nodes outside the local area still use greedy thought to forward. Meanwhile, this paper improves the "cavity problem" and the recovery strategy in GPCR. The next hop routing selected by right-handed decision is likely to be forwarded away from the destination node. The improved recovery strategy combines the position and angle of the vehicle. In the VANET environment which needs Qos guarantee. The MAC protocol of single-channel competition is facing a very serious challenge. It can not meet the demand of higher network capacity and transmission rate. Multi-channel MAC protocol is applied. This paper proposes a multi-channel MAC protocol which takes into account the node density and service traffic. On the premise of ensuring the communication performance, the number of handoffs is reduced as little as possible. The nodes with high node density and large service information flow are divided into 伪 mode. When the node density is high, but the service information flow is divided into 尾 mode. The nodes in the other cases are divided into 纬 modes. According to the characteristics of different modes, different message sending modes are adopted, and the methods of judging and switching between the three modes are given. The PID algorithm and adaptive algorithm for dynamically adjusting the number of periods are given. Under the condition of ensuring the reliable transmission of the security information, the SCH channel is allocated reasonably to ensure the transmission of the security information. As far as possible to meet the service needs of users, improve the data bandwidth. Finally, this paper on the OMNET platform. With SUMO as the traffic simulator, Veins, an open source simulation framework for inter-vehicle communication, is used to simulate GPCR-D and multi-channel MAC protocol. The experimental results show that. The packet delivery rate and transmission delay are improved and have better communication performance.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U495;U463.67;TN929.5

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