目    錄

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

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

   第一章  緒論..........................................1

1.1 OFDM的意義和背景........................................1

1.2 OFDM的歷史及發(fā)展 2

1.3 OFDM系統(tǒng)的優(yōu)缺點 3

1.3.1 OFDM技術(shù)的優(yōu)點 3

1.3.2 OFDM技術(shù)的缺點 4

    第二章  OFDM技術(shù) 4

2.1  OFDM基本原理 4

2.2  OFDM的主要傳輸技術(shù) 5

2.2.1 串并轉(zhuǎn)換 5

2.2.2 DFT變換 5

2.2.3 保護間隔和循環(huán)前綴 7

2.2.4 加窗技術(shù) 8

2.2.5 OFDM基本參數(shù)的選擇 9

    第三章  信道估計 9

3.1 基礎(chǔ)介紹 10

3.2 幾種常見的信道估計算法 11

3.2.1 一般系統(tǒng)信道估計模型 11

3.2.2 基于LS算法的信道估計………………………………………….13

3.2.3 基于DFT的信道估計算法 14

3.2.4 基于濾波器的信道估計算法 18

3.2.5 最大似然估計算法 20

3.2.6 信道估計算法總結(jié) 23

第四章  基于LS和DFT算法信道估計 24

4.1  基于LS和DFT算法信道估計的MATLAB實現(xiàn) 24

4.2  仿真分析及比較…………………………………………………… .24

    第五章  總結(jié)...........,,...........................24

參考文獻(xiàn)……………………………………………………………… 26

致  謝..................................................28

附  錄…………………………………………………………………29

                                摘　　要

在無線信道環(huán)境下，可靠、高速的數(shù)據(jù)傳輸是無線通信系統(tǒng)主要目標(biāo)。正交頻分復(fù)用(OFDM)作為一種可以有效對抗符號間干擾(ISI)和載波干擾（ICI）的高速傳輸技術(shù)得到了廣泛應(yīng)用，而信道估計技術(shù)作為其關(guān)鍵技術(shù)之一也得到了很大的發(fā)展。信道估計是進(jìn)行相干檢測、解調(diào)和均衡的基礎(chǔ)，它對OFDM（正交頻分復(fù)用）技術(shù)實現(xiàn)高速率的數(shù)據(jù)通信起著至關(guān)重要的作用。OFDM（正交頻分復(fù)用）系統(tǒng)以其抗多徑衰落和較高的頻帶利用率，在眾多領(lǐng)域得到了應(yīng)用。OFDM是實現(xiàn)無線通信的關(guān)鍵技術(shù)之一，針對OFDM通信系統(tǒng)特點, 本文對其信道估計技術(shù)進(jìn)行研究,首先第一章介紹了OFDM的意義和背景，OFDM的歷史及發(fā)展和OFDM系統(tǒng)的優(yōu)缺點。第二章重點介紹了OFDM技術(shù)，包括OFDM的基本原理以及OFDM的主要傳輸技術(shù)。第三章在此基礎(chǔ)上對信道估計作了重點介紹，先對信道估計作了個基礎(chǔ)的介紹，緊接著介紹了幾種常見的信道估計算法，最后重點介紹了基于LS算法DFT信道估計算法的OFDM 系統(tǒng)的基本信道估計方法，并用MATLAB語言實現(xiàn)了基于LS算法DFT信道估計算法信道估計的計算機仿真。

關(guān)鍵詞： 正交頻分復(fù)用　　信道估計 LS算法　　DFT信道估計算法　　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;