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

【摘要】：軍事電子偵察,軍事對抗是未來信息戰(zhàn)的基礎,然而無線信道的多徑衰落、信號干擾等因素導致信號產生了嚴重的碼間串擾。為了檢測和恢復有用信號,針對這種特殊環(huán)境的非合作通信系統(tǒng),研究人員嘗試通過信號檢測技術、調制識別、盲均衡等技術來降低碼間干擾,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均衡技術,它僅需要接收序列本身的統(tǒng)計信息來均衡信道特性,能夠很好地應用于非合作通信。正交頻分復用(OFDM)技術是典型的多載波調制方式之一,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,在此基礎上,采用數(shù)據復用以及變步長迭代處理了非合作接收中短數(shù)據的問題,分析了改進后算法性能。論文主要工作如下：1.基于OFDM多載波調制,建立了基于Bussgang性質的盲均衡模型,給出了MCMA算法、MMM A算法和DD算法的均衡表達式。進而得到MMMA-DD多模均衡算法的切換準則和算法框圖。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,針對短數(shù)據難以收斂的問題,選擇分段數(shù)據復用技術；為了進一步加快收斂速度,提高均衡性能,提出了基于剩余符號間干擾(ISI)的變步長迭代技術。在短數(shù)據輸入的條件下,驗證了復用技術對MMMA_DD的算法均衡性能的改善。研究了在變步長條件下,MMMA_DD算法的收斂性能。仿真結果表明,復用技術和變步長技術可以使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.
【學位授予單位】：西安電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.53

【參考文獻】

相關期刊論文 前1條

1 王萍,單超;神經網絡在通信中的應用[J];現(xiàn)代電子技術;2003年13期

，

本文編號：2066313