本文關(guān)鍵詞：融合DFT及小波去噪的OFDM信道估計算法研究　出處：《江西理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： OFDM 信道估計 DFT 閾值 小波去噪

【摘要】：隨著科技的進步,越來越多的新技術(shù)被提出以及被使用,OFDM技術(shù)作為LTE的關(guān)鍵技術(shù)成為了眾多研究人員研究的熱點。運用OFDM技術(shù)的目的是防止符號間的干擾以及信道之間的干擾。作為OFDM技術(shù)關(guān)鍵部分的信道估計技術(shù)得到了重點關(guān)注,信道估計出現(xiàn)使得恢復(fù)出的信道狀態(tài)信息變得更加精確,使系統(tǒng)性能得到了提升。本文圍繞OFDM估計方法進行深入探究,對于經(jīng)典估計方法不足地方提出相應(yīng)地改進算法,對于研究內(nèi)容以及創(chuàng)新點進行如下闡述。(1)研究了無線信道基本特性,分析了在實際環(huán)境當(dāng)中無線信道經(jīng)歷的各種衰落。對于信號在無線信道之中受到了符號間干擾以及信道間干擾情況,研究OFDM原理以及其關(guān)鍵技術(shù),其中介紹了OFDM導(dǎo)頻的三種結(jié)構(gòu)以及三種常見估計算法。針對如何能夠得出良好信道響應(yīng)值的問題探究了幾種實際運用當(dāng)中常見的插值算法。(2)研究了在閾值基礎(chǔ)上面進行改進DFT估計方法,信號經(jīng)過離散化之后往往會造成頻譜泄露,針對信道當(dāng)中出現(xiàn)的這種情況提出了加入海明窗進行解決。對于經(jīng)典DFT估計算法不能夠濾除掉循環(huán)前綴以內(nèi)噪聲的問題,提出了加入改進閾值進行去噪的方法。該閾值法能夠很好地消除信道中突發(fā)大脈沖噪聲的影響,并對該算法進行MATLAB仿真實驗。實驗結(jié)果顯示,改進算法在誤比特率方面最小以及在均方誤差方面也是最小,所以該改進算法能夠很好地提升估計性能。(3)研究了在小波基礎(chǔ)上面進行改進DFT估計方法,對于傳統(tǒng)的DFT-MMSE估計算法不足提出加入小波改進方法。相對于DFT與閾值相融合算法不足點還提出了運用小波去噪以及閾值去噪相融合的改進算法。該算法是在LS信道估計之后加入小波分解并通過運用軟閾值法對信號進行去除噪聲操作,緊接著對得出的信號進行離散傅里葉反變換后再一次進行閾值處理來更深程度地減少噪聲。通過仿真實驗顯示,這兩種算法能夠很好地減少噪聲影響,提升了系統(tǒng)的性能。
[Abstract]:With the progress of science and technology, more and more new technologies have been proposed and used OFDM technology as the key technology of LTE has become the research focus of many researchers. The use of OFDM technology to prevent interference between inter symbol interference and channel. As the key part of OFDM channel estimation technology has been the focus of attention, channel the estimation of the channel state information recovery becomes more accurate, the system performance has been improved. This paper focuses on the estimation method of OFDM in-depth research, for the classical estimation method deficiencies and put forward corresponding improvement algorithm, the research content and innovation are as follows in this paper. (1) studied the basic characteristics of wireless channel fading, analysis in the actual environment of wireless channel. The signal received through inter symbol interference and channel in wireless channel interference. Status of the principle of OFDM and its key technology, which introduces three kinds of structure of OFDM pilot and three kinds of estimation algorithms. Based on how to obtain the good channel response values of several research practice common interpolation algorithm. (2) studied the estimation method based on improved DFT threshold. After the signal after discretization often caused by spectrum leakage, the channel appeared in the proposed adding Hamming window to solve the problem. For the classical DFT estimation algorithm can not eliminate the problem of noise within the cyclic prefix, puts forward some improved threshold denoising method. The threshold method can effectively eliminate channel burst large pulse noise, and MATLAB simulation experiment of the algorithm. The experimental results show that the improved algorithm in the bit error rate and the minimum mean square error is the most Small, so the improved algorithm can effectively enhance the estimation performance. (3) studied the improved DFT estimation method in wavelet based on the traditional DFT-MMSE estimation algorithm is proposed. With improved wavelet less than DFT and threshold fusion algorithm shortcomings also puts forward improved algorithm using wavelet denoising and threshold denoising the fusion of wavelet decomposition. The algorithm is added by using the soft threshold method to remove noise signal after LS channel estimation, followed by inverse discrete Fourier transform again after threshold processing to a deeper degree of reduce noise on the signal. The simulation results show that the two algorithms can be very good to reduce noise, improve the performance of the system.

【學(xué)位授予單位】：江西理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN929.53

【參考文獻】

相關(guān)期刊論文 前10條

1 朱益民;陳小敏;方竹;朱秋明;;MIMO多中繼系統(tǒng)中基于不完全信道狀態(tài)信息的預(yù)編碼算法研究[J];信號處理;2017年02期

2 韋世紅;周小宇;唐宏;;短波OFDM系統(tǒng)中基于迭代插值的信道估計[J];電視技術(shù);2016年06期

3 劉順蘭;汪佳麗;;改進的基于DFT的OFDM系統(tǒng)信道估計算法[J];計算機工程與應(yīng)用;2016年19期

4 李泳志;陶成;劉留;盧艷萍;劉凱;;萊斯信道下分布式大規(guī)模MIMO系統(tǒng)基站選擇算法的研究[J];電子與信息學(xué)報;2016年04期

5 徐鳳陽;王東;肖揚;寇金鋒;;大規(guī)模MIMO系統(tǒng)中基于子空間跟蹤的半盲信道估計[J];應(yīng)用科學(xué)學(xué)報;2015年05期

6 陳艷杰;王丹;;協(xié)作通信系統(tǒng)信道估計算法研究[J];計算機仿真;2015年08期

7 劉海濤;尹志勝;張學(xué)軍;;頻率選擇性瑞利衰落信道脈沖熄滅OFDM接收機差錯性能分析[J];北京郵電大學(xué)學(xué)報;2015年04期

8 黃天聰;何昊宸;馮文江;賈年龍;;AF-OFDM非對稱通信雙向中繼系統(tǒng)能效優(yōu)化[J];系統(tǒng)工程與電子技術(shù);2015年11期

9 練柱先;余江;徐麗敏;肖文珂;劉言立;夏鍇;;一種快速的LMMSE多徑信道估計算法[J];中南大學(xué)學(xué)報(自然科學(xué)版);2014年12期

10 杜軍;曲彥臣;趙衛(wèi)疆;耿利杰;劉闖;張瑞亮;陳振雷;;相位調(diào)制激光多普勒頻移測量方法的誤差研究[J];光學(xué)學(xué)報;2014年07期

相關(guān)碩士學(xué)位論文 前1條

1 黃茜茜;LTE下行鏈路的信道估計算法研究[D];江西理工大學(xué);2016年

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