發(fā)布時間：2018-03-17 10:44

  本文選題：多輸入多輸出　切入點(diǎn)：正交頻分復(fù)用　出處：《西安電子科技大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：近年來,無線移動通信技術(shù)和相關(guān)應(yīng)用開始蓬勃發(fā)展起來,但是頻譜資源不足問題已經(jīng)成為阻礙其發(fā)展的瓶頸。如何在保證傳輸可靠性的前提下提高系統(tǒng)頻譜效率和信道容量已成為無線通信領(lǐng)域研究的焦點(diǎn)。多輸入多輸出(MIMO)依靠空間復(fù)用技術(shù)可以提高數(shù)據(jù)傳輸速率,增加信道容量。正交頻分復(fù)用(OFDM)是一種特殊的多載波調(diào)制技術(shù),它的每個子載波之間相互正交,可以提供更高的頻譜利用率。MIMO-OFDM系統(tǒng)同時具備二者的優(yōu)勢方面,然而該系統(tǒng)對同步誤差非常敏感,非理想同步往往會顯著降低系統(tǒng)性能,因此精確的時間和頻率同步對該系統(tǒng)來說尤為重要。本文旨在探討集中式非合作MIMO-OFDM系統(tǒng)在移動無線信道下的盲時頻同步技術(shù),主要工作如下:1.首先對MIMO通信系統(tǒng)模型及其信道容量、OFDM技術(shù)基本原理及其優(yōu)缺點(diǎn)進(jìn)行了闡述;其次對MIMO-OFDM系統(tǒng)模型及其所涉及的主要關(guān)鍵技術(shù)進(jìn)行了重點(diǎn)介紹;最后,對移動無線信道進(jìn)行了詳細(xì)的闡述并進(jìn)行了數(shù)學(xué)建模。2.建立了非合作MIMO-OFDM無線通信系統(tǒng)模型。從系統(tǒng)時域信號模型出發(fā),對非理想定時同步對解調(diào)信號的影響進(jìn)行了理論分析,并對結(jié)果進(jìn)行了計算機(jī)仿真驗證。同時還介紹了現(xiàn)有合作MIMO-OFDM通信中常用的Mody和ZelstSchenk符號定時同步算法。3.針對MIMO-OFDM物理幀結(jié)構(gòu)的循環(huán)前綴特性,設(shè)計了一種有效符號長度盲估計算法。分析了最大似然定時同步算法的不足并對針對它進(jìn)行改進(jìn),提出了基于延遲相關(guān)集系數(shù)的盲幀長與定時同步聯(lián)合估計算法。首先定義延遲相關(guān)集系數(shù),然后將它與幀長在正常取值的有效范圍內(nèi)進(jìn)行二維搜索,從而確定物理幀長度,并根據(jù)此時延遲相關(guān)集系數(shù)隨采樣點(diǎn)位置所呈現(xiàn)的變化規(guī)律確定定時同步位置,最后通過仿真驗證了提出算法的有效性和可靠性。4.分析了非理想頻率同步對MIMO-OFDM系統(tǒng)的影響,介紹了現(xiàn)有合作通信中常用的頻偏估計方案。通過對多徑信道下接收信號模型所具有的數(shù)學(xué)性質(zhì)進(jìn)行深入分析,提出了一種基于聚類的自適應(yīng)MIMO-OFDM盲時頻同步算法,該算法不需要信道參數(shù)、空時編碼類型等先驗信息,可以克服多徑的影響,估計性能較好。最后,通過MATLAB仿真驗證了該算法能夠在非合作移動通信場景下實(shí)現(xiàn)高精度的時頻同步。
[Abstract]:In recent years, wireless mobile communication technology and related applications began to flourish, However, the problem of insufficient spectrum resources has become the bottleneck that hinders its development. How to improve the system spectrum efficiency and channel capacity under the premise of ensuring the transmission reliability has become the focus of research in the field of wireless communication. Using spatial multiplexing technology can improve the data transmission rate. Increasing channel capacity. Orthogonal Frequency Division Multiplexing (OFDM) is a special multicarrier modulation technology. Each of its sub-carriers is orthogonal to each other, which can provide a higher spectrum efficiency. MIMO-OFDM system has the advantages of both. However, the system is very sensitive to synchronization errors, and non-ideal synchronization often significantly reduces the performance of the system. Therefore, accurate time and frequency synchronization is particularly important for the system. This paper aims to discuss the blind time-frequency synchronization technology for centralized non-cooperative MIMO-OFDM systems in mobile wireless channels. The main work is as follows: 1. Firstly, the basic principle, advantages and disadvantages of MIMO communication system model and its channel capacity are described. Secondly, the MIMO-OFDM system model and its main key technologies are introduced emphatically. In this paper, the mobile wireless channel is described in detail and the mathematical model is established. The model of non-cooperative MIMO-OFDM wireless communication system is established. Based on the time-domain signal model of the system, the influence of non-ideal timing synchronization on the demodulation signal is analyzed theoretically. The results are verified by computer simulation. At the same time, Mody and ZelstSchenk symbol timing synchronization algorithms, which are commonly used in cooperative MIMO-OFDM communication, are introduced. 3. The cyclic prefix characteristics of MIMO-OFDM physical frame structure are discussed. An effective blind symbol length estimation algorithm is designed, and the shortcomings of the maximum likelihood timing synchronization algorithm are analyzed and improved. A joint estimation algorithm of blind frame length and timing synchronization based on delay correlation set coefficient is proposed. Firstly, the delay correlation set coefficient is defined, and then two-dimensional search is carried out with the frame length in the valid range of normal values to determine the physical frame length. The timing synchronization position is determined according to the variation of the delay correlation set coefficient with the sample location. Finally, the validity and reliability of the proposed algorithm are verified by simulation. Finally, the influence of non-ideal frequency synchronization on the MIMO-OFDM system is analyzed. This paper introduces the frequency offset estimation schemes commonly used in cooperative communication. By analyzing the mathematical properties of the received signal model in multipath channel, an adaptive MIMO-OFDM blind time-frequency synchronization algorithm based on clustering is proposed. The proposed algorithm does not require prior information such as channel parameters, space-time coding types and so on. It can overcome the influence of multipath and has good estimation performance. Finally, The simulation results of MATLAB show that the proposed algorithm can achieve high precision time-frequency synchronization in non-cooperative mobile communication scenarios.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN929.53

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 謝小芳;童崢嶸;萬人瑋;楊秀峰;薛玉明;;相干光正交頻分復(fù)用系統(tǒng)定時同步的改進(jìn)算法[J];光電子.激光;2010年06期

2 王育紅,薛筱明,樊昌信,李建東;一種新的波特率采樣定時同步方法[J];電子科學(xué)學(xué)刊;1998年04期

3 趙亮;李競翔;杜玉海;孫中森;;一種改進(jìn)的符號定時同步算法的研究[J];電波科學(xué)學(xué)報;2013年04期

4 劉旺;朱江;付永明;郄志鵬;;一種并行的定時同步環(huán)路實(shí)現(xiàn)研究[J];通信技術(shù);2013年10期

5 余新強(qiáng);易淼;;全數(shù)字接收機(jī)的定時同步研究[J];大眾科技;2009年01期

6 吳天帆;歸琳;熊箭;;國標(biāo)地面數(shù)字電視接收機(jī)定時同步算法的改進(jìn)[J];電視技術(shù);2010年04期

7 徐翔輝;段田東;韓俊峰;鄭彩美;;一種短波突發(fā)信號的聯(lián)合定時同步結(jié)構(gòu)[J];計算機(jī)應(yīng)用與軟件;2010年07期

8 徐凡;郭見兵;劉永飄;;帶分?jǐn)?shù)延時功能的符號同步環(huán)路的設(shè)計與實(shí)現(xiàn)[J];電視技術(shù);2012年13期

9 龔岳洲;周新力;王文琰;孫小東;;基于最大平均功率的定時同步算法[J];科學(xué)技術(shù)與工程;2012年32期

10 龔岳洲;周新力;孫小東;孟慶萍;;基于正弦波形的定時同步算法[J];計算機(jī)應(yīng)用與軟件;2013年10期

相關(guān)會議論文 前10條

1 楊魁;韓彥明;馬明;;軟件無線電接收機(jī)中的定時同步研究[A];2008年中國高校通信類院系學(xué)術(shù)研討會論文集（下冊）[C];2009年

2 張哲;;MC-CDMA定時同步算法改進(jìn)[A];2006中國西部青年通信學(xué)術(shù)會議論文集[C];2006年

3 李新明;;一種新的基于IEEE802.11n定時同步算法[A];2014年9月建筑科技與管理學(xué)術(shù)交流會論文集[C];2014年

4 潘小飛;劉愛軍;張邦寧;王杭先;方華;;基于EM算法的符號定時同步[A];第十三屆全國信號處理學(xué)術(shù)年會（CCSP-2007）論文集[C];2007年

5 史濟(jì)剛;金寧;金小萍;;IEEE802．16a系統(tǒng)的符號定時同步算法[A];2006通信理論與技術(shù)新進(jìn)展——第十一屆全國青年通信學(xué)術(shù)會議論文集[C];2006年

6 張菊茜;舒治安;郭黎利;;一種新的OFDM系統(tǒng)定時同步算法[A];中國造船工程學(xué)會電子技術(shù)學(xué)術(shù)委員會2006學(xué)術(shù)年會論文集（上冊）[C];2006年

7 代濤;周R，

本文編號：1624391