无线快衰落信道研究毕业论文

武汉轻工大学 毕 业 设 计（论 文）

设计(论文)题目：无线快衰落信道研究

目录

中文摘要................................................................ -1- 英文摘要................................................................ -2- 前言.................................................................... -3- 1 无线移动通信技术的发展及应用........................................... 4

1.1 无线移动通信技术发展历史和趋势[5]..................................... 4 1.2 无线移动通信技术相关业务及频谱 ...................................... 4 1.3 无线移动通信技术应用设想 ............................................ 6 本章小结 ................................................................ 7 2 无线信道的概念和特性................................................... 8

2.1 无线信道的定义 ...................................................... 8 2.2 无线信道的类型 ...................................................... 8

2.2.1 传播路径损耗模型............................................... 8 2.2.2 大尺度传播模型................................................. 9 2.2.3 小尺度传播模型................................................. 9 2.3 无线移动信道的概念 .................................................. 9 2.4 移动信道的特点 ...................................................... 9

2.4.1 移动通信信道的3个主要特点..................................... 9 2.4.2 移动通信信道的电磁波传输...................................... 10 2.4.3 接收信道的3类损耗............................................ 10 2.4.4 三种快衰落（选择性衰落）产生的原因............................ 10 2.4.5 接收信号的4种效应............................................ 10 本章小结 ............................................................... 11 3 移动信道的传输特性和信道模型.......................................... 11

3.1 传输损耗的初步定量分析 ............................................. 11

3.1.1 大范围传输损耗的定量分析...................................... 11 3.1.2 中小范围传输损耗的定量分析.................................... 13 3.1.3 移动信道中的噪声和干扰........................................ 13 本章小结 ............................................................... 14

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4 CDMA技术 ........................................................... 14 4.1 CDMA技术含义 ........................................................ 14 4.2 CDMA技术的优点 ...................................................... 14 结论..................................................................... 16 本章小结................................................................. 15 致谢..................................................................... 16 参考文献................................................................. 17

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中文摘要

摘 要

无线网络技术的日趋成熟成为主流。移动通信的发展速度非常的快，而无线信道是移动通信中传输信号的媒介，只有深刻掌握和了解移动无线信道的特征，我们才能提出解决各种干扰的措施。这对于提高系统的抗噪声性能和提高系统的传输可靠性都具有非常重要的作用。信道是对无线通信中发送端和接收端之间的通路的一种形象比喻，信道具有一定的频率带宽，正如公路有一定的宽度一样。由于移动体周围有许多散射、反射和折射体，引起信号的多径传输，使到达的信号之间相互叠加，其合成信号幅度表现为快速的起伏变化，本论文简要介绍了移动无线信道的基本概念、特点、分类及理论知识上，针对移动无线信道中信号传输环境的复杂性和随机性，结合MATLAB软件运用数字信号处理方法仿真分析了无线信道各信号受多径干扰的情况.主要阐述了无线网络传播路径和传输技术具备的信号特性，以及可以避免衰落最常见的影响。研究关于多径和多普勒效应导致的小范围衰落对通信的破坏力。

关键词：无线通信；快衰落；无线频段；多径传输；移动信道

英文摘要

STUDY ON FAST FADING CHANNEL

ABSTRACT

The maturity of the wireless network technology has become the mainstream. The development speed of mobile communication is very fast, and the wireless channel is the transmission signal media in mobile communication, only to master and understand the characteristics of mobile wireless channel, we can solve all kinds of interference measures. It is very important to improve the anti noise performance of the system and improve the reliability of the transmission system. The channel is an image of channel in wireless communication between the sending end and receiving end of metaphor, the channel is frequency bandwidth, as the road has a certain width. Because there are many scattering, reflection and refraction body moving around the body, caused by the multipath signals, the overlap between signals arriving, the synthetic signal amplitude showed fluctuation changes quickly, this paper briefly introduces the basic concept, the characteristics of wireless channel, classification and theoretical knowledge, for the complexity of the mobile environment signal transmission in wireless channel and randomness, combined with the MATLAB application software of the wireless channel by each signal multipath interference signal simulation processing digital. Mainly expounds the signal characteristics with wireless network transmission path and transmission technology, and can avoid the effect of fading of the most common. A small study about the multipath fading and Doppler effects of fading on the destructive power of communication.

Keywords:

wireless communication; fast fading; wireless spectrum; multipath

propagation; mobile channel