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  本文選題：高階QAM + 盲均衡�。� 參考：《哈爾濱工業(yè)大學(xué)》2017年碩士論文

【摘要】：與低階調(diào)制相比,高階QAM調(diào)制由于其較高的頻帶利用率,更多地應(yīng)用在高速寬帶通信系統(tǒng)中。在實(shí)際信道上進(jìn)行高速數(shù)字信號的傳輸時,由傳輸信道的帶寬受限和多徑效應(yīng)而引起的碼間串?dāng)_,會造成接收信號在幅度和相位上的失真,導(dǎo)致在接收端進(jìn)行符號檢測時產(chǎn)生較大的誤碼率,因而需要對接收信號進(jìn)行均衡。而在不能提供訓(xùn)練序列的場景下,就必須采用盲均衡技術(shù)。在矢量信號分析系統(tǒng)中,隨著QAM調(diào)制階數(shù)和傳輸符號速率的增大,由信道引入的碼間串?dāng)_將對接收信號造成更加惡劣的影響,與此同時,在接收端進(jìn)行盲均衡的復(fù)雜度也會隨之加大。因此,研究適用于矢量信號分析系統(tǒng)的高階QAM盲均衡算法具有重要意義。本文以實(shí)現(xiàn)矢量信號分析系統(tǒng)中64QAM、256QAM的盲均衡為目標(biāo),針對是否存在載波頻偏兩種條件展開理論研究。首先,建立全數(shù)字調(diào)制解調(diào)系統(tǒng)等效基帶模型,為后續(xù)研究奠定基礎(chǔ);然后,在不考慮載波頻偏的條件下,對適用于高階QAM調(diào)制的多模盲均衡算法及其改進(jìn)算法進(jìn)行深入研究和仿真分析,最終采用基于SMMA的雙模式盲均衡算法作為無頻偏條件下的高階QAM盲均衡方案;接著,針對存在較大頻偏的情況,在分析載波頻偏、相偏對盲均衡算法的影響和對幾類閉環(huán)載波恢復(fù)算法研究的基礎(chǔ)之上,給出了兩種盲均衡與載波恢復(fù)聯(lián)合結(jié)構(gòu),通過仿真分析,聯(lián)合結(jié)構(gòu)II與聯(lián)合結(jié)構(gòu)I相比達(dá)到收斂需要的符號數(shù)更少,但前置的CMA均衡器達(dá)到穩(wěn)態(tài)需要消耗一定的時間,進(jìn)而確定適用于矢量信號分析系統(tǒng)的盲均衡與載波恢復(fù)聯(lián)合方案。最后,在算法實(shí)現(xiàn)上,給出適用于矢量信號分析系統(tǒng)中高符號速率下高階QAM的盲均衡與載波恢復(fù)聯(lián)合實(shí)現(xiàn)框架。理論分析和實(shí)際數(shù)據(jù)測試表明,該方案引入的理論殘差可以忽略不計,在實(shí)際300Msps符號速率下消除ISI的同時,能夠?qū)崿F(xiàn)符號速率10%范圍內(nèi)的頻偏校正,且三種頻偏測試條件下系統(tǒng)輸出的EVM都達(dá)到了1%左右,從而驗(yàn)證其有效性。
[Abstract]:Compared with low order modulation, high order QAM modulation is more applied in high speed broadband communication system because of its high bandwidth utilization. When transmitting high speed digital signal on the actual channel, inter code crosstalk caused by bandwidth limitation and multipath effect of the transmission channel will result in distortion on amplitude and phase of received signal. It is necessary to equalizer the received signal, and the blind equalization technique must be adopted in the scene where the training sequence can not be provided. In the vector signal analysis system, the inter code crosstalk introduced by the channel will be butted with the increase of the QAM modulation order and the transmission symbol rate. At the same time, the complexity of blind equalization at the receiver will increase. Therefore, it is of great significance to study the high order QAM blind equalization algorithm for vector signal analysis system. This paper aims at the blind equalization of 64QAM and 256QAM in vector signal analysis system. Firstly, the equivalent baseband model of all digital modulation and demodulation system is established, which lays the foundation for the follow-up study. Then, under the condition of carrier frequency offset, the multi mode blind equalization algorithm and its improved algorithm suitable for high order QAM modulation and its improved algorithm are deeply studied and simulated. Finally, the SMMA based method is used. The double mode blind equalization algorithm is used as the high order QAM blind equalization scheme without frequency offset. Then, based on the analysis of the influence of carrier frequency offset, the phase offset to the blind equalization algorithm and the study of several closed loop carrier recovery algorithms, two kinds of blind equalization and carrier recovery joint structures are given. In comparison with the joint structure II, the number of symbols required for convergence is less than that of the joint structure I, but the pre CMA equalizer needs a certain amount of time to reach the steady state, and then the joint scheme of blind equalization and carrier recovery for vector signal analysis system is determined. Finally, the algorithm is applied to the vector signal analysis system. The blind equalization of high order QAM and carrier recovery are combined to implement the framework. Theoretical analysis and actual data test show that the theoretical residuals introduced by the scheme can be ignored and can eliminate ISI at the actual 300Msps symbol rate, and can realize the frequency offset correction in the 10% range of symbol rate, and the system is under the condition of three frequency offset tests. The output EVM reaches about 1%, so as to verify its effectiveness.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN911.5

【參考文獻(xiàn)】

相關(guān)期刊論文 前9條

1 楊賓;吳瑛;;一種適用于高階QAM信號的均衡與載波恢復(fù)聯(lián)合實(shí)現(xiàn)算法[J];信息工程大學(xué)學(xué)報;2015年03期

2 牛聰;高勇;;一種基于切換步長的加權(quán)多模盲均衡算法[J];現(xiàn)代電子技術(shù);2013年19期

3 李進(jìn);馮大政;劉文娟;;快速Q(mào)AM信號多模盲均衡算法[J];電子與信息學(xué)報;2013年02期

4 王雷;吳長奇;;針對線性群時延畸變的加權(quán)多模盲均衡算法[J];信號處理;2012年07期

5 薛偉;楊小牛;張朝陽;;一種改進(jìn)的加權(quán)多模盲均衡算法[J];系統(tǒng)仿真學(xué)報;2011年03期

6 許小東;戴旭初;徐佩霞;;適合高階QAM信號的加權(quán)多模盲均衡算法[J];電子與信息學(xué)報;2007年06期

7 潘立軍;劉澤民;;兩種改進(jìn)的盲均衡算法[J];電路與系統(tǒng)學(xué)報;2006年02期

8 高鷹,謝勝利;一種變步長LMS自適應(yīng)濾波算法及分析[J];電子學(xué)報;2001年08期

9 蔣明峰,鄭小林,彭承琳;一種新的變步長LMS自適應(yīng)算法及其在自適應(yīng)噪聲對消中的應(yīng)用[J];信號處理;2001年03期

相關(guān)博士學(xué)位論文 前1條

1 李進(jìn);QAM信號盲（半盲）均衡算法研究[D];西安電子科技大學(xué);2015年

相關(guān)碩士學(xué)位論文 前1條

1 梁中法;高階QAM信號盲均衡算法研究[D];西安電子科技大學(xué);2014年

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本文編號：1951933