本文選題：非合作通信 + 正交頻分復(fù)用　； 參考：《西安電子科技大學(xué)》2014年碩士論文

【摘要】：軍事電子偵察,軍事對(duì)抗是未來信息戰(zhàn)的基礎(chǔ),然而無線信道的多徑衰落、信號(hào)干擾等因素導(dǎo)致信號(hào)產(chǎn)生了嚴(yán)重的碼間串?dāng)_。為了檢測(cè)和恢復(fù)有用信號(hào),針對(duì)這種特殊環(huán)境的非合作通信系統(tǒng),研究人員嘗試通過信號(hào)檢測(cè)技術(shù)、調(diào)制識(shí)別、盲均衡等技術(shù)來降低碼間干擾,抵抗信道的影響,取得了較好的效果。盲均衡是一種新興的自適應(yīng)均衡技術(shù),它僅需要接收序列本身的統(tǒng)計(jì)信息來均衡信道特性,能夠很好地應(yīng)用于非合作通信。正交頻分復(fù)用(OFDM)技術(shù)是典型的多載波調(diào)制方式之一,不僅能夠抵抗多徑帶來的干擾,而且還可以有效地提高系統(tǒng)的帶寬利用率。論文基于OFDM多載波系統(tǒng)模型,在多徑衰落的信道條件下,研究了非合作通信中OFDM的盲均衡技術(shù),在此基礎(chǔ)上,采用數(shù)據(jù)復(fù)用以及變步長(zhǎng)迭代處理了非合作接收中短數(shù)據(jù)的問題,分析了改進(jìn)后算法性能。論文主要工作如下：1.基于OFDM多載波調(diào)制,建立了基于Bussgang性質(zhì)的盲均衡模型,給出了MCMA算法、MMM A算法和DD算法的均衡表達(dá)式。進(jìn)而得到MMMA-DD多模均衡算法的切換準(zhǔn)則和算法框圖。比較了MMMA_DD和MCMA算法均衡后的星座圖,誤符號(hào)率曲線,均方誤差,剩余碼間干擾；研究了不同信噪比、不同多徑信道條件下MMMA_DD多模算法的性能。研究表明,MMMA_DD算法比MCMA算法性能更優(yōu)異。并且MMMA_DD算法在不同信噪比,不同多徑信道條件下都有良好的均衡效果。2.在非合作通信中,針對(duì)短數(shù)據(jù)難以收斂的問題,選擇分段數(shù)據(jù)復(fù)用技術(shù)；為了進(jìn)一步加快收斂速度,提高均衡性能,提出了基于剩余符號(hào)間干擾(ISI)的變步長(zhǎng)迭代技術(shù)。在短數(shù)據(jù)輸入的條件下,驗(yàn)證了復(fù)用技術(shù)對(duì)MMMA_DD的算法均衡性能的改善。研究了在變步長(zhǎng)條件下,MMMA_DD算法的收斂性能。仿真結(jié)果表明,復(fù)用技術(shù)和變步長(zhǎng)技術(shù)可以使MMMA_DD算法獲得很好的均衡效果。本論文研究成果為非合作通信系統(tǒng)多載波調(diào)制的均衡提供一定的理論參考。
[Abstract]:Military electronic reconnaissance and military confrontation are the basis of future information warfare. However, the multipath fading of wireless channel and signal interference cause serious inter-symbol crosstalk. In order to detect and recover useful signals, researchers try to reduce inter-symbol interference (ISI) and resist the influence of channel by signal detection, modulation recognition, blind equalization and so on. Good results have been achieved. Blind equalization is a new adaptive equalization technique. It only needs the statistical information of the received sequence to equalize the channel characteristics. It can be applied to non-cooperative communication. Orthogonal Frequency Division Multiplexing (OFDM) is one of the typical multicarrier modulation schemes, which can not only resist the interference caused by multipath, but also improve the bandwidth efficiency of the system. Based on the OFDM multicarrier system model, the blind equalization technology of OFDM in non-cooperative communication is studied under the condition of multipath fading channel. On this basis, data multiplexing and variable step size iteration are used to deal with the problem of non-cooperative receiving medium and short data. The performance of the improved algorithm is analyzed. The main work of this paper is as follows: 1. The blind equalization model based on Bussgang property is established based on OFDM multicarrier modulation, and the equalization expressions of MCMA algorithm and DD algorithm are given. Then the switching criterion and block diagram of MMMA-DD multimode equalization algorithm are obtained. The constellation diagram, symbol error rate curve, mean square error and residual inter-symbol interference (ISI) of MMMADD and MCMA algorithms are compared, and the performance of MMMASP multimode algorithm with different signal-to-noise ratio and multipath channel is studied. The results show that MMMADD algorithm has better performance than MCMA algorithm. Moreover, MMMA _ s _ DD algorithm has good equalization effect under different SNR and multi-path channels. In non-cooperative communication, the piecewise data multiplexing technique is chosen to solve the problem that short data is difficult to converge. In order to further accelerate the convergence speed and improve the equalization performance, a variable step size iterative technique based on residual Intersymbol interference (ISI) is proposed. Under the condition of short data input, the performance of MMMADD algorithm is improved by multiplexing technology. The convergence performance of MMMADD algorithm with variable step size is studied. The simulation results show that the multiplexing technique and variable step size technique can make MMMADD algorithm achieve a good equalization effect. This paper provides a theoretical reference for multi-carrier modulation equalization in non-cooperative communication systems.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN929.53

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 王萍,單超;神經(jīng)網(wǎng)絡(luò)在通信中的應(yīng)用[J];現(xiàn)代電子技術(shù);2003年13期

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