【摘要】：低軌衛(wèi)星通信系統(tǒng)可以實現(xiàn)全球無縫覆蓋,解決地面通信網(wǎng)的盲區(qū)覆蓋問題或稀有用戶密度區(qū)域的基本通信問題,同時在出現(xiàn)自然災(zāi)害或熱點地區(qū),作為地面通信網(wǎng)的備份和補充。以蜂窩技術(shù)為起點,地面移動通信近年來得到了快速的發(fā)展,為實現(xiàn)更高的數(shù)據(jù)通信速率,3GPP提出OFDMA技術(shù)和MIMO技術(shù),經(jīng)過多年研究最終提出了LTE通信協(xié)議。近幾年來LTE應(yīng)用技術(shù)的快速發(fā)展,將LTE技術(shù)應(yīng)用于低軌衛(wèi)星的通信系統(tǒng)成為了一個全新的研究熱點。本文研究了LTE協(xié)議在低軌衛(wèi)星場景中的應(yīng)用,分析衛(wèi)星信道的特點,提出了低軌衛(wèi)星信道模型,采用LTE通信協(xié)議中的關(guān)鍵技術(shù)搭建并改進適應(yīng)低軌衛(wèi)星的上行鏈路系統(tǒng)。同時本文的仿真分析大都基于該衛(wèi)星上行鏈路系統(tǒng)。本論文首先分析研究了LTE上行隨機接入與同步的過程,分析并提出了LTE標(biāo)準(zhǔn)應(yīng)用于低軌衛(wèi)星場景會產(chǎn)生的問題。設(shè)計新的前導(dǎo)序列結(jié)構(gòu)以適應(yīng)長時延的低軌衛(wèi)星環(huán)境,并仿真驗證在衛(wèi)星鏈路中新前導(dǎo)序列結(jié)構(gòu)的檢測性能。針對LTE系統(tǒng)應(yīng)用到低軌衛(wèi)星上時由于大多普勒頻移帶來的頻率不同步問題,本文分析研究了頻率偏移的估計算法,并根據(jù)低軌衛(wèi)星的應(yīng)用場景對整數(shù)頻偏的估計算法加以改進,并進行仿真驗證其估計性能。最后分析研究傳統(tǒng)的地面LTE系統(tǒng)中的定時提前量TA問題,提出了適應(yīng)于低軌衛(wèi)星大時延場景下的定時提前量策略。同時針對衛(wèi)星鏈路下發(fā)射端與接收端存在定時誤差的問題,采用現(xiàn)有的定時偏移估計算法進行補償,并對現(xiàn)有的時偏估計算法進行改進,通過仿真驗證算法的估計性能,實現(xiàn)了低軌衛(wèi)星定時偏移的估計與補償,提升了鏈路系統(tǒng)的通信性能。
[Abstract]:Leo satellite communication system can achieve seamless global coverage, solve the problem of blind area coverage of terrestrial communication network or the basic communication problem of rare user density area, and at the same time, in areas of natural disasters or hot spots, As a backup and supplement of terrestrial communication network. Based on cellular technology, terrestrial mobile communication has been developed rapidly in recent years. In order to achieve higher data communication rate, 3GPP proposed OFDMA and MIMO technology, and finally proposed LTE communication protocol after many years of research. With the rapid development of LTE application technology in recent years, the application of LTE technology to Leo satellite communication system has become a new research hotspot. In this paper, the application of LTE protocol in Leo satellite scenario is studied, the characteristics of satellite channel are analyzed, the channel model of Leo satellite is proposed, and the key technology of LTE communication protocol is used to build and improve the uplink system adapted to Leo satellite. At the same time, the simulation analysis of this paper is mostly based on the satellite uplink system. In this paper, the process of LTE uplink random access and synchronization is analyzed and studied, and the problems arising from the application of LTE standard in Leo satellite scenarios are analyzed and proposed. A new preamble sequence structure is designed to adapt to the low-orbit satellite environment with long delay, and the detection performance of the new preamble sequence structure in satellite links is verified by simulation. In order to solve the problem of frequency unsynchronization caused by large Doppler frequency shift when LTE system is applied to Leo satellite, this paper analyzes and studies the estimation algorithm of frequency offset, and improves the estimation algorithm of integer frequency offset according to the application scene of Leo satellite. The estimation performance is verified by simulation. Finally, the problem of TA in the traditional ground LTE system is analyzed, and the strategy of timing advance is proposed, which is suitable for the low-orbit satellite with large time-delay. At the same time, aiming at the problem of timing error between transmitter and receiver under satellite link, the existing timing offset estimation algorithm is used to compensate, and the existing time offset estimation algorithm is improved, and the performance of the algorithm is verified by simulation. The timing offset estimation and compensation of Leo satellite is realized, and the communication performance of the link system is improved.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN927.23

【參考文獻】

相關(guān)期刊論文 前7條

1 葉歡;;LTE系統(tǒng)中符號定時同步算法的研究[J];信息技術(shù);2016年07期

2 He Yizhou;Cui Gaofeng;Li Pengxu;Chang Ruijun;Wang Weidong;;Random access preamble design based on time pre-compensation for LTE-satellite system[J];The Journal of China Universities of Posts and Telecommunications;2015年03期

3 米楊;張曉瀛;魏急波;;三維模型中的多普勒功率譜分析[J];通信技術(shù);2015年04期

4 WANG Jun;QIN Qi-zhen;LIU Shou-yin;LI Ting;;Low complexity joint time offset and frequency offset estimations for LTE uplink system[J];The Journal of China Universities of Posts and Telecommunications;2014年06期

5 蔣杭州;陳曉冬;;LTE物理信道容量理論分析[J];電信科學(xué);2013年S1期

6 王淑紅;;多徑衰落的數(shù)學(xué)模型及分析[J];無線電工程;2010年10期

7 鄒銳;全球星系統(tǒng)(Globalstar)技術(shù)介紹[J];電子科技導(dǎo)報;1999年07期

相關(guān)博士學(xué)位論文 前1條

1 何異舟;下一代衛(wèi)星移動通信系統(tǒng)關(guān)鍵技術(shù)研究[D];北京郵電大學(xué);2015年

相關(guān)碩士學(xué)位論文 前4條

1 李源;多天線LTE上行鏈路SC-FDMA系統(tǒng)載波同步技術(shù)研究[D];廣東工業(yè)大學(xué);2014年

2 杜駿t，

本文編號：2443197