長期演進(jìn)論文：LTE系統(tǒng)下行鏈路的信道估計(jì)研究.doc

長期演進(jìn)論文：LTE系統(tǒng)下行鏈路的信道估計(jì)研究【中文摘要】LTE是未來10年內(nèi)最具影響力的寬帶移動(dòng)通信標(biāo)準(zhǔn)之一,為了提高數(shù)據(jù)傳輸效率和頻譜利用率,LTE系統(tǒng)下行鏈路采用了正交頻分復(fù)用(OFDM)技術(shù)。信道估計(jì)是OFDM系統(tǒng)的關(guān)鍵技術(shù),估計(jì)的精度直接影響整個(gè)系統(tǒng)的性能,本文主要研究常見的信道估計(jì)算法在LTE下行鏈路的應(yīng)用。首先對(duì)LTE的啟動(dòng)背景和物理層做了一個(gè)簡單的介紹,講述了OFDM和MIMO技術(shù)的基本原理。接下來討論了無線信道的基本特性和一些重要的物理參數(shù),并且分析了它們對(duì)無線通信系統(tǒng)的影響。然后對(duì)常見的導(dǎo)頻位置信道估計(jì)算法做了理論推導(dǎo),包括LS估計(jì)算法,基于DFT的信道估計(jì)算法和LMMSE信道估計(jì)算法,同時(shí)介紹了一些常見的插值算法,并對(duì)這些常見的信道估計(jì)算法做了仿真分析。本文把重點(diǎn)放在基于DFT的信道估計(jì)算法在LTE下行鏈路的應(yīng)用研究上,也就是第四章的內(nèi)容。第四章首先提出了一種基于DFT的信道估計(jì)算法在LTE下行鏈路的應(yīng)用方案,然后對(duì)基于DFT的信道估計(jì)算法的不足之處做了分析和改進(jìn)。比較了適用于LTE系統(tǒng)的兩種抑制邊緣效應(yīng)的算法重復(fù)邊緣值法和部分子載波替換法。通過仿真得出重復(fù)邊緣值法性能更好,并將其應(yīng)用到LTE下行鏈路中。接下來提出了一種改進(jìn)的時(shí)域加窗算法,仿真結(jié)果表明改進(jìn)算法有一定的性能提升,而且算法實(shí)現(xiàn)簡單,適合LTE下行鏈路。最后對(duì)LTE下行多天線系統(tǒng)做了性能仿真分析,仿真結(jié)果進(jìn)一步驗(yàn)證了本文所提出方案的可行性?！居⑽恼縇TE is one of the most influential broadband mobile communication standards in the next 10 years. In order to increase data transmission efficiency and spectral efficiency, LTE systems adopted orthogonal frequency division multiplexing (OFDM) technology as the downlink transmission technology. Channel estimation is the key technology of OFDM systems, the estimated accuracy directly affects the system performance. This paper mainly studied the application of common channel estimation algorithm in LTE downlink.Firstly, the start background and the physical layer of LTE are introduced briefly, and the basic principles of OFDM and MIMO technologies are described. The discussion of the basic characteristics and some important parameters of wireless channel are made in this paper, and their impact on the wireless communication systems is analyzed. Then a detailed description of the common channel estimation is made, including the LS estimation algorithm, DFT-based channel estimation algorithm and LMMSE estimation algorithm. Some common interpolation algorithms are also introduced in this paper. The performance of these common channel estimation algorithms is analyzed through computer simulation.The application of DFT-based channel estimation algorithm in downlink of LTE systems is the focus of this paper, that is, the contents of Chapter 4.An application of DFT-based channel estimation algorithm in the downlink of LTE systems is devised in chapter 4, then the analysis and improvement about the shortcomings of DFT-based channel estimation algorithm is made. Two methods to reduce edge effect (edge value repetition method and part of subcarriers replacement method) are compared by computer simulation, the result shows edge value repetition is better, and it is applied to the downlink of LTE. Then an algorithm for time domain windowing operation is improved. The simulation results show that the performance of the improved algorithm is better than traditional algorithm. The improved algorithm is easy to implement by hardware, and is suitable for the downlink of LTE systems. Finally, the performance of multi-antenna systems of LTE is analyzed through computer simulation, and the simulation results further verify the feasibility of the proposed scheme.【關(guān)鍵詞】長期演進(jìn) 正交頻分復(fù)用 信道估計(jì) 邊緣效應(yīng) 時(shí)域加窗【英文關(guān)鍵詞】LTE OFDM Channel estimation Edge effect Time domain windowing operation【目錄】LTE系統(tǒng)下行鏈路的信道估計(jì)研究摘要6-7Abstract7-8第1章 緒論11-211.1 LTE項(xiàng)目的啟動(dòng)背景11-121.2 LTE物理層協(xié)議和關(guān)鍵技術(shù)簡介12-181.2.1 LTE幀結(jié)構(gòu)12-131.2.2 資源單元和資源塊13-141.2.3 LTE中OFDM技術(shù)簡介14-171.2.4 LTE中MIMO技術(shù)簡介17-181.3 信道估計(jì)的意義和研究現(xiàn)狀18-191.4 本文的主要工作和章節(jié)安排19-21第2章 無線信道21-282.1 無線信道的特性21-242.1.1 大尺度衰落21-222.1.2 小尺度衰落22-242.2 無線信道的輸入/輸出模型24-252.3 空間信道模型25-28第3章 信道估計(jì)技術(shù)28-383.1 參考信號(hào)位置的信道估計(jì)算法28-333.1.1 LS算法29-303.1.2 LMMSE算法30-313.1.3 基于DFT降噪的信道估計(jì)算法31-333.2 數(shù)據(jù)位置的信道估計(jì)33-343.2.1 常值插值法333.2.2 線性插值算法333.2.3 基于DFT的插值算法33-343.2.4 階插值算法343.3 信道估計(jì)算法仿真分析34-38第4章 LTE下行信道估計(jì)算法研究38-604.1 LTE下行參考信號(hào)圖案及序列生成38-414.2 基于DFT降噪的信道估計(jì)算法在LTE下行鏈路中的應(yīng)用研究41-514.2.1 一種基于DFT的信道估計(jì)算法在LTE