VANET动态多路径路由协议

发布时间：2018-01-04 13:17

本文关键词：VANET动态多路径路由协议　出处：《吉林大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着现代城市车辆数目的持续增加，车载电子产品的使用场景变的越来越广泛，这些应用包括道路交通信息查询、交通事故告警、高速公路缴费、拥塞警报和车辆间语音视频通话等，车载成员还能够使用车载自组织网路（Vehicular Ad-hoc Networks,VANET）达到数据共享与传输（如传输文件、上传视频）、连入Internet以及互动游戏等目的。在种种美好、值得期待的VANET互联应用中，路由协议充当了至关重要的角色。然而，找到一个合适的城市环境多跳路由机制仍是一个挑战，这主要有三个因素：首先，车载自组织网络VANET具有节点密度分布不均匀、车辆高速移动和快速的网络拓扑结构变化等特征。其次，路由需要适应大规模网络系统的可伸缩性，然而无线通信距离受限，并且很容易受到不同拓扑结构（如建筑物）的影响。最后，VANET中紧急报文需要较高的数据包投递率和低网络延迟，这点在VANET环境下传统路由模式无法得到满足。与传统的路由协议相比，基于地理位置的路由协议已经被证明更适用于高移动性的VANET网络。这些地理路由多采用贪婪或者既定路线的方式向前传送数据包。但是由于VANET中车辆拓扑结构的频繁变化和道路中车辆密度的不确定性以及传播途径中障碍物的阻挡，导致地理路由经常遇到局部最大和道路车辆稀疏的问题。并且当一段道路中有较多的数据包传输时，由于无线信道的特点，该道路的数据传输延迟增加，丢包率上升。针对以上问题，本文在电子地图和车辆位置获取的基础上提出一种动态多路径路由协议(Dynamic Multi-path Routing，DMPR)。需要说明的是，DMPR主要应用在城市环境的VANET中。由于城市中的车辆移速存在上限，DMPR认为在一个较小的时间段内，可以假设各路径的传输特性不变。DMPR在数据传输开始时选择多条路径传输数据，在传输的过程中监控各条路径的实时传输特性并根据各个路径不同的实时传输特性动态的调整沿各条路径传输的数据量。通过这样的方式，，DMPR利用协议本身的机制动态调整数据沿不同路径的传输比例，使得沿性能相对较好的路途传输较多的信息，减少该数据包在同一路径上与其他较多数据包的信道竞争，从而从整体上提高VANET的数据传输性能。DMPR更适用于源节点和目的节点传输连接时间较长的通信，因为较长的数据传输时间有利于DMPR的动态调整。本文使用NS2（Network Simulator version2）这一网络仿真软件对DMPR进行验证。首先在NS2中编写C++代码实现DMPR路由协议的逻辑机制，再将编写的代码成功安装到NS2中并重新编译，然后使用MOVE模拟真实城市车流信息，最后利用MOVE产生的车流信息使用OTCL实现实验场景。为了说明DMPR在城市环境中具有较好的传输性能，将DMPR与经典的Ad-hoc路由协议AODV、GPSR和GSR在同样的情景下做性能对比，通过实验说明DMPR较其它协议在端到端延迟和数据包投递率上有更好的表现。
[Abstract]:With the number of modern city vehicles continues to increase, the vehicle electronic product usage scenarios become more and more widely, these applications include road traffic information, traffic accident alarm, highway toll, congestion alarm and inter vehicle video calling, vehicle members can also use the vehicular ad hoc network (Vehicular Ad-hoc Networks, VANET) to achieve data share and transfer (such as file transfer, video upload), connected to the Internet and interactive games. In a variety of good, VANET worth looking forward to the Internet applications, routing protocol plays a vital role.
However, to find a suitable city environment of multi hop routing mechanism is still a challenge, there are three main factors: first, VANET VANET nodes with uneven density distribution, vehicle high speed mobile and rapid change of network topology characteristics. Secondly, the need to adapt to the scalability of a large-scale network system however, the wireless communication distance is limited, and are susceptible to different topological structures (such as buildings) influence. Finally, VANET emergency message requires a higher packet delivery ratio and low network delay, which can not be met in the traditional routing model in VANET environment.
Compared with the traditional routing protocol, routing protocol based on geographical location has proved to be more suitable for high mobility VANET network. The use of greedy geographic routing or established route way forward packets. But due to frequent changes and obstacles blocking the density of vehicles in road VANET vehicle topology and the uncertainty in the transmission way in the result, geographic routing often encounter local maximum and road vehicles sparse problems. And when the transmission more road in the packet, due to the characteristics of wireless channel, the data transmission path delay increases, the packet loss rate increases. To solve the above problems, based on the electronic map and vehicle position acquisition proposed a dynamic multi path routing protocol (Dynamic Multi-path Routing, DMPR). That is, DMPR is mainly used in the city environment in VANET.
As a result of the city's vehicle speed ceiling exists, DMPR believes that in time a smaller, can assume the transmission characteristics of each path in the same.DMPR in the beginning of data transmission, select multiple paths to transmit data, data real-time monitoring of transmission characteristics of each path in the process of transmission and the transmission characteristics of each path according to the real-time dynamic different adjustment along the transmission path. By this way, the DMPR mechanism is used to dynamically adjust the data protocol itself along the transmission path of the different proportion, the relative performance of road transport more and better information, reduce the packet channel contention packet and other more data on the same path, so as to improve the the data transmission performance of.DMPR VANET on the whole is more suitable for communication in the transmission source node and destination node connection time longer, because data transmission time is longer in favor of DMP The dynamic adjustment of R.
This paper uses NS2 (Network Simulator version2) the network simulation software to verify the logic mechanism of DMPR. First write C++ code to implement DMPR routing protocol in NS2, then the code successfully installed into NS2 and recompile, and then simulate the real city traffic information using MOVE, finally using MOVE generated traffic information OTCL realize the experimental scene. In order to illustrate DMPR has better transmission performance in the city environment, the routing protocol of Ad-hoc DMPR and the classic AODV, GPSR and GSR performance comparison in the same scenario, through experiments that DMPR compared with other protocols in end-to-end delay and better packet delivery ratio.

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U463.6;U495

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