【正文】 多載波傳輸方案，多載波調(diào)制本質(zhì)上是一種頻分復(fù)用 (FDM, Frequency Division Multiplex)技術(shù)。t be maintained, serious intercarrier interference is introduced. Therefore precise timing and frequency offset estimation is very important for OFDM systems. So we study the synchronization of the OFDM systems in the thesis. Main works in the thesis: Firstly, the principle and the primary technology of OFDM systems is introduced in the article, in addition it introduces the advantages and disadvantages of the OFDM systems. Secondly, we study the synchronization principle and analyze the performance influence in OFDM systems which have the errors of timing synchronization、 frequency synchronization and the sampling rate synchronization. Thirdly, the synchronization algorithm based on cyclic prefix of theory analysis and simulation implementation, put forward a kind of make full use of the cyclic prefix and the corresponding part of the correlation of the improved algorithm, which is the focus of future research. Finally, the graduation design made a summary and outlook Keywords: orthogonal frequency division multiplexing； synchronization； symbol timing offset estimation；frequency offset 目錄 緒論 ........................................................................................................................ 1 研究背景 .......................................................................................................... 1 國(guó)內(nèi)外研究現(xiàn)狀 ............................................................................................... 2 本文的主要工作及內(nèi)容安排 .............................................................................. 3 OFDM 系統(tǒng)原理及關(guān)鍵技術(shù) ....................................................................................... 4 OFDM 系統(tǒng)原理 ................................................................................................... 4 OFDM 系統(tǒng)的基本模型 .............................................................................. 4 OFDM 系統(tǒng)的調(diào)制和解調(diào)原理 ................................................................... 4 保護(hù)間隔和循環(huán)前綴 .............................................................................. 6 建立 OFDM系統(tǒng)仿真模型 .......................................................................... 7 OFDM 技術(shù)的優(yōu)缺點(diǎn) .......................................................................................... 10 OFDM 系統(tǒng)的關(guān)鍵技術(shù) ...................................................................................... 10 本章小結(jié) .......................................................................................................... 12 OFDM 系統(tǒng)的同步技術(shù)分析 ...................................................................................... 12 OFDM 系統(tǒng)中的同步原理 ................................................................................... 12 同步偏差對(duì) OFDM 系統(tǒng)性能的影響 ................................................................. 17 載波同步偏差分析 ............................................................................... 17 OFDM 系統(tǒng)的同步算法 ...................................................................................... 18 本章小結(jié) ........................................................................................................ 19 基于循環(huán)前綴的同步算法 ...................................................................................... 19 OFDM聯(lián)合同步算法 .................................................................. 19 ML 估計(jì)原理 ........................................................................................... 20 ML 算法仿真估計(jì) .................................................................................... 21 本章小結(jié) ........................................................................................................ 24 總結(jié)與展望 ........................................................................................................... 24 全文總結(jié) ........................................................................................................ 24 ............................................................................................ 25 致謝 ............................................................................................................................... 26 參考文獻(xiàn) ........................................................................................................................ 27 第 1 頁(yè) 共 33 頁(yè) 緒論 研究背景 近年來，移動(dòng)通信技術(shù)發(fā)展迅速，已經(jīng)從第一代模擬通信系統(tǒng)過渡到第二代數(shù)字通信系統(tǒng)，并已經(jīng)開始第三代移動(dòng)通信系統(tǒng)的商業(yè)化部署和第四代移動(dòng)通信技術(shù)標(biāo)準(zhǔn)的研究，網(wǎng)絡(luò)的不斷升級(jí)換代帶來了傳輸速率的不斷提高，第三代移動(dòng)通信系統(tǒng)最大傳輸速率可達(dá)到 2Mbps。 其次，研究了 OFDM 系統(tǒng)中的同步原理，并分析了系統(tǒng)中存在的載波同步偏差、樣值同步偏差、符號(hào)定時(shí)同步偏差對(duì)系統(tǒng)性能造成的影響。在 OFDM 系統(tǒng)中，進(jìn)行精確的時(shí)頻偏差估計(jì)非常重要。 題 目 OFDM 的基本原理與關(guān)鍵技術(shù)研究 學(xué)生姓名 陳 悠 學(xué)號(hào) 1113024080 所在學(xué)院 物 理 與 電 信 工 程 學(xué) 院 專業(yè)班級(jí) 通 信 工 程 專 業(yè) 1103 班 指導(dǎo)教師 王 桂 寶 完成地點(diǎn) 物 理 與 電 信 工 程 學(xué) 院 實(shí) 驗(yàn) 室 2020 年 5 月 31 日 OFDM 的基本原理和關(guān)鍵技術(shù)研究 陳悠 （ 陜西理工學(xué)院物理與電信工程學(xué)院通信 1103班，陜西 漢中 723003） 指導(dǎo)教師：王桂寶 [摘 要 ] OFDM(Orthogonal Frequency Division Multiplexing)是未來移動(dòng)通信中具有應(yīng)用前景和競(jìng)爭(zhēng)力的一項(xiàng)技術(shù)。當(dāng)存在頻率偏差時(shí)，子載波之間的正交性遭到破壞，從而引起嚴(yán)重的載波間干擾。并對(duì)系統(tǒng)存在的優(yōu)缺點(diǎn)進(jìn)行了分析和歸納。符號(hào)定時(shí)偏移估計(jì)；頻率偏移估計(jì) Research on basic principle and key technology of OFDM ChenYou (Grade 11,Class 3,Major of Communication Engineering， School of Physics and telemunication Engineering of Shaanxi University of Technology, Hanzhong 723003,China) Tutor: Wang Guibao Abstract: Orthogonal Frequency Division Multiple (OFDM) is an effective and promising technique in future mobile munications. It has efficient bandwidth utilization and the robustness against Multipath delay, and else it is easier to implement the modulation and demodulation. But OFDM is ve