發(fā)布時(shí)間：2018-10-29 10:22

【摘要】：本文研究了基于OFDM系統(tǒng)的壓縮感知信道估計(jì)中導(dǎo)頻模式的選取和DDLMMSE信道估計(jì)算法。建立了壓縮感知應(yīng)用于信道估計(jì)中的數(shù)學(xué)模型,并對壓縮感知信道估計(jì)中如何選取最優(yōu)的導(dǎo)頻模式進(jìn)行了研究,提出了一種改進(jìn)的選取方法,通過仿真驗(yàn)證了結(jié)果;闡明了DDLMMSE信道估計(jì)算法存在的不足并提出了改進(jìn)算法,仿真實(shí)驗(yàn)驗(yàn)證了改進(jìn)算法的優(yōu)越性。主要研究內(nèi)容包括:(1)提出了一種改進(jìn)的壓縮感知信道估計(jì)導(dǎo)頻選取方法。理論分析和仿真實(shí)驗(yàn)證明了利用相關(guān)性衡量觀測矩陣并用其最小準(zhǔn)則選取導(dǎo)頻模式存在的缺陷,因而提出利用加權(quán)相關(guān)函數(shù)來代替相關(guān)性,彌補(bǔ)了利用相關(guān)性選取導(dǎo)頻模式的缺陷。將用加權(quán)相關(guān)函數(shù)選出的導(dǎo)頻模式進(jìn)行信道估計(jì),利用OMP及LS算法重構(gòu)出信道響應(yīng)。100次Monte Carlo實(shí)驗(yàn)結(jié)果表明,利用加權(quán)相關(guān)函數(shù)選則的導(dǎo)頻模式進(jìn)行信道估計(jì)的結(jié)果中,30%優(yōu)于相關(guān)性選擇的導(dǎo)頻模式,68%與相關(guān)性選取的導(dǎo)頻模式相同,2%的其他情況;通過對加權(quán)相關(guān)函數(shù)的仿真得出,當(dāng)總的循環(huán)次數(shù)在300次左右時(shí),加權(quán)相關(guān)趨于收斂,因此將循環(huán)次數(shù)設(shè)為300,減少仿真運(yùn)行的時(shí)間。(2)提出了一種改進(jìn)的DDLMMSE信道估計(jì)算法。DDLMMSE信道估計(jì)算法是對LS算法進(jìn)行修正所得,改進(jìn)的DDLMMSE信道估計(jì)算法利用子載波間的相關(guān)性,將DDLMMSE算法中的對角陣擴(kuò)展到K重矩陣,在不顯著增加算法復(fù)雜度的前提下,提高信道估計(jì)的精度。仿真表明,當(dāng)誤碼率一定時(shí),隨著K的增加需要的信噪比減小,K為3時(shí)比K為1時(shí)所需的信噪比約減小0.5d B,因此,可以根據(jù)對性能的要求來選取合適的K。
[Abstract]:In this paper, pilot mode selection and DDLMMSE channel estimation algorithm in compressed perceptual channel estimation based on OFDM system are studied. The mathematical model of compressed sensing applied to channel estimation is established, and how to select the optimal pilot mode in compressed perceptual channel estimation is studied. An improved selection method is proposed, and the results are verified by simulation. The shortcomings of the DDLMMSE channel estimation algorithm are clarified and the improved algorithm is proposed. The simulation results demonstrate the superiority of the improved algorithm. The main contents are as follows: (1) an improved pilot selection method for compressed perceptual channel estimation is proposed. Theoretical analysis and simulation experiments prove the defects of selecting pilot mode by using correlation measurement observation matrix and its minimum criterion. Therefore, a weighted correlation function is proposed to replace correlation. It makes up for the defect of selecting pilot mode by correlation. The pilot mode selected by weighted correlation function is used for channel estimation, and the channel response is reconstructed by using OMP and LS algorithms. The results of 100 Monte Carlo experiments show that the pilot mode of weighted correlation function selection is used for channel estimation. 30% is superior to the pilot mode selected by correlation, 68% is the same as the pilot mode selected by correlation, and 2% is other cases. Through the simulation of the weighted correlation function, when the total number of cycles is about 300 times, the weighted correlation tends to converge, so the number of cycles is set to 300, (2) an improved DDLMMSE channel estimation algorithm is proposed. The DDLMMSE channel estimation algorithm is a modified LS algorithm, and the improved DDLMMSE channel estimation algorithm utilizes the correlation between subcarriers. The diagonal matrix in the DDLMMSE algorithm is extended to the K-multiplicity matrix, which improves the accuracy of channel estimation without significantly increasing the complexity of the algorithm. Simulation results show that when the bit error rate is constant, the SNR required by K decreases with the increase of K, and the SNR required by K at 3 is about 0.5 dB lower than that required by K at 1. Therefore, appropriate Ks can be selected according to the performance requirements.
【學(xué)位授予單位】：天津理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN929.53

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 張建康;陳恩慶;穆曉敏;齊林;;OFDM系統(tǒng)中一種最大似然信道估計(jì)算法[J];兵工學(xué)報(bào);2009年09期

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本文編號：2297420