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1、精品资料推荐 无无线线城城市市建建设设中中W WL LA AN N 室室外外覆覆盖盖规规划划设设计计与与路路 径径损损耗耗模模型型研研究究 摘要摘要 无线局域网是计算机网络与无线通信技术相结合的产物。它利用射频 （RF）技术，取代旧式的双绞线构成局域网络，提供传统有线局域网的所有功 能。无线网络所需的基础设施不需再埋在地下或隐藏在墙里，并且可以随需移 动或变化。WLAN 已经成为宽带接入的有效手段之一，使用 WLAN 的区域及其承 载的业务愈来愈多。为了更好地构建理想中的无线网络，我们需要进行合理的 布局规划，而为了能够合理地进行布局规划，我们首先要对 WLAN 的路径损耗模 型进行计算分析。
2、本文首先分析了现在常用的几种路径损耗模型，然后用 COST-231-Walfisch-Ikegami 模型来分别计算分析在大城市密集城区环境下不 同的街区轴线和连接发射机和接收机天线的夹角，不同的移动台有效天线高度， 不同的街道宽度对路径损耗的影响，得到以下三条结论(1) 将 WLAN 室外覆盖 系统可容忍最大路径损耗值作为参考进行系统基站 AP 的布局规划, 可进行立 体网布局, 低天线高度的 AP 负责街道、广场和低楼层覆盖, 高天线高度的 AP 负责对较高 楼层的覆盖;(2) 为了扩大单 AP 的覆盖范围, 考虑使用高功率、 高接收灵敏度的 AP/ 基站, 同时考虑使用高增益的天线/ 智
3、能天线或塔顶放大 器来提高系统可容忍最大路径损耗值, 从而实现有效的 WLAN 信号覆盖；（3） 在街道宽度较小的地区部署 WLAN 网络时，离屋顶下沿最近的衍射引起的衰落比 较明显，必须考虑给接收信号强度一个合适的衰落储备，以保证用户接收到的 信号质量。然后对- 模型进行分析计算，对两个模型 进行对比，进一步印证了以上三条结论，并分析了在不同场景下两大模型的优 劣，从而为无线局域网规划时的路径损耗模型选用以及布局策略提供了有价值 的参考信息。 关键词：WLAN ；室外覆盖规划与设计； 路径损耗 ；COST231- Walfish-Ikegami 模型； 模型 Abstract WLAN is
4、 a new technology that combined with computer network technology and wireless communication technology. It uses radio frequency (RF) technology, to 精品资料推荐 replace the old twisted pair constitute a local area network, to provide all the functions that traditional wired Network provided.Wireless netwo
5、rk infrastructure do not need to be buried or hidden in the wall, and can move or change with Customers need .WLAN has become one of the effective means for broadband access, more and more region deployed WLAN and more and more business carried by WLAN .In order to construct the ideal wireless netwo
6、rk, we need to carry on the reasonable layout, and to be able to reasonably layout planning, we should first of all to do the WLAN path loss models calculation and analysis.This paper first analyzed several commonly used path- loss model, and then selected the COST231-Walfish-Ikegami model to analyz
7、e how the loss-path changed with the three Impact factor-the angle between Block axis and the line that connected the transmitter and the receiver,the Mobile stations Height and the Street width .then we get out the following three conclusions： (1) when we put the WLAN outdoor coverage systems maxim
8、um tolerate path -loss value as a reference to planning our systems AP layout planning, we can three- dimensional network layout,low antenna height of the AP is responsible for streets, squares and low-floor coverage,while high antenna height of the AP is responsible for covering the upper floors; (
9、2) in order to expand the coverage of a single AP, we may consider to use the AP/ base station that have high power and high receiver sensitivity ,at the same time to achieve effective WLAN signal coverage ,we need to taking account of the high gain antennas / smart antenna or tower-mounted amplifie
10、rs to improve the systems tolerated maximum path loss value; (3) when deploying WLAN networks in areas with smaller width of the street , the path-loss that caused by the diffraction from the nearest roof-along is more obvious ,so we must consider to give the received signal strength a fading margin
11、 to ensure the users signal quality. Then I analyzed the COST231-Hata model , comparing the two models, and further more confirms the conclusion of the above three references, at the same time I analyzed the pros and cons of the two models in different settings so as to provides some valuable refere
12、nce information for the path loss model selection and layout strategy in wireless LAN planning. Key words: WLAN；outdoor coverage planning and design；path loss； COST231- Walfish-Ikegami model; COST231-hata model 目录目录 第一章 绪论.1 精品资料推荐 1.1 课题来源 .1 1.2 国内外研究现状 .1 第二章 无线城市建设中 WLAN 室外覆盖规划设计.3 2.1 无线城市简介.3 2.2 WLAN 简介 .3 2.2.1 无线局域网的优点.3 2.2.2 无线局域网的理论基础.4 2.2.3 无线局域网的不足之处.5 2.3 WLAN 协议标准 .5 2.3.1IEEE802.11 系列协议.5 2.3.2 蓝牙规范（Bluetooth） .7 2.3.3 HomeRF 标准.7 2.3.4 HyperLAN/2 标准.7 2.4 无线局域网标准的比较 .
