【作者】 李彦平；

【导师】 杨家玮；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2003， 硕士

【摘要】 移动自组网(Mobile Ad hoc Networks，简称MANET)属于无基础设施、无中心的移动无线网络，所有节点都能够移动并以任意拓扑方式动态连接，可应用于军事通信、应急通信、临时通信等需要快速布署、动态组网的通信场合。以前对该网络的研究几乎都针对或默认为收发节点采用全向天线，本文主要研究其采用定向天线后的网络实现的关键技术。首先阐述了定向天线在网络空分复用(SDMA)、天线增益、抗干扰等方面的的优势，分析了定向天线用于移动自组网的可行性，接着重点研究了基于定向天线的多址接入协议和路由协议，分析了与全向天线在组网和协议实现中的异同点和优缺点，并对特定的环境下的网络性能作了对比。本文提出的定向路由协议DS_DSR是基于对现有协议DSR的改进下实现的，通过定向邻节点路由表、定向源路由和定向搜索来完成路由发现与维护。研究发现，定向天线的应用，相比全向天线可明显提高网络的总的吞吐量，减少信道干扰、多址干扰，提高信干噪比，且由于定向天线的高增益可实现较远距离、较少跳数的通信，减少了路由发现时间，这样大大减小了传输时延，网络的整体性能得到了不同程度的提高，同时部分地解决安全问题，通过功率控制还可较容易的实现节能的目的。 为了方便网络协议性能仿真，使移动自组网的接入协议和路由协议能够在同一个模板上实现，本文在仿真平台OPNET设计了IEEE802.11框架下的移动自组网节点模型和定向天线模型等，并通过对现有协议的改进，实现了特定网络性能的计算机仿真。更多还原

【Abstract】 Mobile Ad hoc Networks (MANET) is infrastructureless network .It set up by the nodes which can move and link arbitrarily with no centre node in topology, extensively apply in all quick arrangements, dynamic situation ,such as the military ,an emergency correspondence, temporary communication ,etc. Previous research on the Ad hoc network almost aim at omnidirectional antenna of all receivers and transmitters ,or as a default attribution .In my thesis ,firstly I describe the advantages of the directional antenna at many aspects which including spatial division multiple access( SDMA), the antenna gain, anti- interference etc. and analyze the possibility about the directional antenna used for the ad hoc networks, secondly I study its multiple access and routine protocols using the directional antenna. And compare the protocol difference and network" performance between omnidirectional and directional antenna in particular environment. The directional routing protocol DS_DSR put forward by the author is the improvement of the current protocol DSR , complete routine discovery and maintenance by directional neighbor nodes routing table, source routing and directional steering.The research discovers the application of the directional antenna, compare the omnidirectional antenna can increases the networks’ total throughput, obviously reduces the co_channel interference (CCI), multiple access interference ( MAI), enlarges the nodes "signal and interference to noise ratio( SINR), and because of the high gain of directional antenna can realize the communication with farther distance and less jump, end to end delay can decrease deeply, simultaneously, security of networks can be improved partially, the node energy also can be saved easily by power control.For the sake of the convenient network simulation, I select a same framework in my MAC and routine protocols’ simulation, that is IEEE802.11 standard built in soft tool OPNET, by designing my network node model and directional antenna model, and the improvement of the current protocols, I realizes the evaluation of my special networks.更多还原