基于matlab环境的ofdm信道估计方法研究.doc

目    录

摘 要....................................................1

Abstract.................................................2  

   第一章  绪论..........................................1

1.1 OFDM的意义和背景........................................1

1.2 OFDM的历史及发展 2

1.3 OFDM系统的优缺点 3

1.3.1 OFDM技术的优点 3

1.3.2 OFDM技术的缺点 4

    第二章  OFDM技术 4

2.1  OFDM基本原理 4

2.2  OFDM的主要传输技术 5

2.2.1 串并转换 5

2.2.2 DFT变换 5

2.2.3 保护间隔和循环前缀 7

2.2.4 加窗技术 8

2.2.5 OFDM基本参数的选择 9

    第三章  信道估计 9

3.1 基础介绍 10

3.2 几种常见的信道估计算法 11

3.2.1 一般系统信道估计模型 11

3.2.2 基于LS算法的信道估计………………………………………….13

3.2.3 基于DFT的信道估计算法 14

3.2.4 基于滤波器的信道估计算法 18

3.2.5 最大似然估计算法 20

3.2.6 信道估计算法总结 23

第四章  基于LS和DFT算法信道估计 24

4.1  基于LS和DFT算法信道估计的MATLAB实现 24

4.2  仿真分析及比较…………………………………………………… .24

    第五章  总结...........,,...........................24

参考文献……………………………………………………………… 26

致  谢..................................................28

附  录…………………………………………………………………29

                                摘　　要

在无线信道环境下，可靠、高速的数据传输是无线通信系统主要目标。正交频分复用(OFDM)作为一种可以有效对抗符号间干扰(ISI)和载波干扰（ICI）的高速传输技术得到了广泛应用，而信道估计技术作为其关键技术之一也得到了很大的发展。信道估计是进行相干检测、解调和均衡的基础，它对OFDM（正交频分复用）技术实现高速率的数据通信起着至关重要的作用。OFDM（正交频分复用）系统以其抗多径衰落和较高的频带利用率，在众多领域得到了应用。OFDM是实现无线通信的关键技术之一，针对OFDM通信系统特点, 本文对其信道估计技术进行研究,首先第一章介绍了OFDM的意义和背景，OFDM的历史及发展和OFDM系统的优缺点。第二章重点介绍了OFDM技术，包括OFDM的基本原理以及OFDM的主要传输技术。第三章在此基础上对信道估计作了重点介绍，先对信道估计作了个基础的介绍，紧接着介绍了几种常见的信道估计算法，最后重点介绍了基于LS算法DFT信道估计算法的OFDM 系统的基本信道估计方法，并用MATLAB语言实现了基于LS算法DFT信道估计算法信道估计的计算机仿真。

关键词： 正交频分复用　　信道估计 LS算法　　DFT信道估计算法　　仿真

      

In the wireless channel environment, reliable, high-speed data transmission is the main goal of a wireless communication system. Orthogonal Frequency Division Multiplexing (OFDM) as a way to effectively combat inter-symbol interference (ISI) and carrier interference (ICI) for high-speed transmission technology has been widely applied, and channel estimation techniques as one of its key technologies have also been very big development. Channel estimation is coherent detection, demodulation and balanced basis, it OFDM (orthogonal frequency division multiplexing) technology to achieve high-speed data communication plays a vital role. OFDM (orthogonal frequency division multiplexing) system with its anti-multipath fading and high bandwidth efficiency, in many areas to the application. OFDM wireless communication is one of the key technologies for OFDM communication system, this paper channel estimation techniques for its study, the first chapter introduces the meaning and context of OFDM, OFDM and OFDM history and development of the system advantages and disadvantages. The second chapter focuses on the OFDM technology, including the basic principles of OFDM and OFDM main transmission technology. Chapter III on the basis of estimates made ​​by the channel focuses first on the basis of channel estimation made ​​a presentation, followed by introduction of several common channel estimation algorithm, and finally focuses on the LS-based channel estimation algorithm of DFT the basic OFDM system channel estimation method and MATLAB language DFT based channel estimation algorithm LS channel estimation algorithm for computer simulation.

Keywords: OFDM Channel estimation; 　LS algorithm; 　DFT　channel estimation algorithm;   simulation;