本文關(guān)鍵詞： 多載波 非線性 OFDM 相干接收 XPM FWM　出處：《北京郵電大學(xué)》2014年博士論文　論文類(lèi)型：學(xué)位論文

【摘要】：近年來(lái),各種高清,超高清視頻業(yè)務(wù)的迅速發(fā)展使得用戶(hù)對(duì)帶寬的需求迅速增加。光纖憑借其良好的抗干擾能力、頻帶寬、損耗低、重量輕及低成本等優(yōu)點(diǎn)被逐步應(yīng)用到骨干網(wǎng)絡(luò)中,“光進(jìn)銅退”已經(jīng)是大勢(shì)所趨。另外,相干光通信的采用使得接收端數(shù)字信號(hào)處理簡(jiǎn)單,色散以及偏振模色散等線性損傷不再是制約速率的關(guān)鍵,而是損耗和非線性效應(yīng)�？梢圆捎瞄_(kāi)發(fā)大有效面積的低損光纖來(lái)解決損耗問(wèn)題,但是非線性效應(yīng)作為世界性的難題,一直是研究中的重點(diǎn)及難點(diǎn),目前還沒(méi)有一種準(zhǔn)確的理論來(lái)估計(jì)或者補(bǔ)償它。所以對(duì)非線性的理論模型分析是值得深入研究的問(wèn)題,只有研究清楚各項(xiàng)系統(tǒng)參數(shù)對(duì)非線性的作用效果,才能進(jìn)一步做出假設(shè),提出非線性的補(bǔ)償算法。 正交頻分復(fù)用(OFDM)是一類(lèi)特殊的多載波調(diào)制技術(shù),由于正交子載波的頻譜可以重疊,具有較高頻譜利用率,是無(wú)線通信中對(duì)抗多徑的關(guān)鍵技術(shù)。自從被引入相干光纖通信中,便以較高的接收機(jī)靈敏度,方便的數(shù)字信號(hào)處理技術(shù),成為下一代超高速長(zhǎng)距離光纖傳輸?shù)氖走x技術(shù)。本文針對(duì)多載波相干光OFDM (CO-OFDM)通信系統(tǒng)中的非線性效應(yīng)的機(jī)理進(jìn)行了深入的研究,從系統(tǒng)平臺(tái)的搭建到線性損傷的信道估計(jì),再到鏈路中非線性作用機(jī)理的分析等,取得了以下創(chuàng)新性的研究成果： 1.針對(duì)多載波CO-OFDM系統(tǒng)中定時(shí)同步敏感的問(wèn)題,提出一種改進(jìn)的的定時(shí)同步算法。該算法能夠有效消除由于循環(huán)前綴產(chǎn)生的定時(shí)測(cè)度曲線峰頂?shù)钠讲ìF(xiàn)象,造成估計(jì)同步時(shí)刻不準(zhǔn)的問(wèn)題,仿真結(jié)果表明該算法能夠準(zhǔn)確估計(jì)符號(hào)定時(shí)時(shí)刻,性能優(yōu)于經(jīng)典的SchimdlCox方法,更適用于光纖信道。 2.針對(duì)112Gbit/s偏分復(fù)用CO-OFDM系統(tǒng),提出一種改進(jìn)的信道估計(jì)算法。這種方法將頻域平均與時(shí)域平均的優(yōu)勢(shì)結(jié)合,可以得到更準(zhǔn)確的信道傳輸矩陣參數(shù),實(shí)現(xiàn)更精確的信道估計(jì)。仿真結(jié)果表明,即使在相對(duì)快速時(shí)變的環(huán)境中系統(tǒng)性能依然平穩(wěn)。當(dāng)群時(shí)延(DGD)等于1000ps時(shí),系統(tǒng)性能相對(duì)符號(hào)內(nèi)頻域平均(ISFA)算法提高了2.2dB,當(dāng)考慮線寬與頻偏的時(shí)候有超過(guò)0.5dB的優(yōu)勢(shì)。 3.針對(duì)112Gbit/s偏分復(fù)用CO-OFDM系統(tǒng)中的非線性問(wèn)題,提出將貝爾實(shí)驗(yàn)室空分編碼(BLAST)算法用來(lái)提高系統(tǒng)的非線性容忍性。本文在不同的色散補(bǔ)償率下進(jìn)行了系統(tǒng)性能的仿真,結(jié)果表明,在無(wú)色散補(bǔ)償,800km傳輸?shù)那闆r下,系統(tǒng)性能相比ISFA算法至少提高了5dB。 4.針對(duì)波分復(fù)用的CO-OFDM系統(tǒng)中的XPM影響,提出采用自相關(guān)特性分析方法分離出交叉相位調(diào)制(XPM)引起的相位噪聲以及偏振串?dāng)_噪聲來(lái)分析系統(tǒng)中XPM的特性。通過(guò)這種分析方法可以清晰的看到系統(tǒng)參數(shù)是如何影響XPM。在OFDM系統(tǒng)中,無(wú)相位恢復(fù)算法情況下驗(yàn)證得出相位噪聲相比串?dāng)_噪聲占主導(dǎo)地位。 5.針對(duì)密集的波分復(fù)用CO-OFDM系統(tǒng)中將鏈路中所有的非線性噪聲看做是四波混頻(FWM)的問(wèn)題,提出由于文獻(xiàn)中過(guò)多的假設(shè)使得該估計(jì)方法不夠精確,從而對(duì)應(yīng)用到其他的調(diào)制格式具有一定的局限性。研究結(jié)果表明,調(diào)整估計(jì)公式中的參數(shù)會(huì)對(duì)理論估計(jì)值產(chǎn)生較大的影響,而在不同的鏈路條件或者系統(tǒng)參數(shù)條件下,使得理論與仿真Q值曲線吻合的最好的的值存在較大的差異,表明這種頻域非線性效應(yīng)估計(jì)方法不夠精確以及不夠完備。 總之,本文從單信道的CO-OFDM系統(tǒng)平臺(tái)出發(fā),從系統(tǒng)的搭建校正,到信道估計(jì),同步估計(jì),相位噪聲估計(jì)再到分析波分復(fù)用CO-OFDM系統(tǒng)中的非線性作用機(jī)理進(jìn)行了比較全面的研究。
[Abstract]:In recent years, the rapid development of a variety of high-definition, ultra high-definition video services makes the demand for bandwidth increases rapidly with its users. The fiber anti-interference ability, good frequency bandwidth, low loss, light weight and low cost has been gradually applied to the backbone network, the "copper back into the light" is represent the general trend. In addition, using coherent optical communication makes the receiving end of the digital signal processing is simple, the dispersion and polarization mode dispersion linear damage is no longer the key control rate, but the loss and the nonlinear effect. Using low loss fiber development of large effective area to solve the problem of loss, but the nonlinear effect as a problem in the world, has been the focus and difficulty of research in, there is not a accurate theory to estimate or compensate it. So the theoretical analysis of the nonlinear model is worthy of further study, only aware of the research The effect of the system parameters on the nonlinearity can be further assumed and the nonlinear compensation algorithm is proposed.
Orthogonal frequency division multiplexing (OFDM) is a kind of special multi carrier modulation technology, the spectrum of orthogonal subcarriers can overlap, has high spectrum efficiency, anti multipath is a key technology in wireless communication. Since being introduced for coherent optical fiber communication, with high sensitivity receiver, digital signal processing technology has become. Ultra high speed long distance optical fiber transmission technology of the next generation. The first choice for multi carrier coherent optical OFDM (CO-OFDM) mechanism of nonlinear effect in communication system are studied, estimated from the system platform to channel linear damage, and then to the mechanism of nonlinear interaction in the link analysis, research achievements the following innovative:
1. for multi carrier CO-OFDM system timing sensitive problem, proposes an improved timing synchronization algorithm. The algorithm can effectively eliminate the timing metric curve peak cyclic prefix generated by the flat wave phenomenon caused by the problem of inaccurate estimation of synchronization time, the simulation results show that the algorithm can accurately estimate the symbol timing, SchimdlCox the method is better than the classical, more suitable for optical fiber channel.
2. for 112Gbit/s polarization division multiplexing CO-OFDM system, proposes an improved channel estimation algorithm. This method will be combined with the advantages of the average frequency of time averaging, can get more accurate parameters of the channel matrix, to achieve more accurate channel estimation. The simulation results show that the performance of the system even in relatively fast time-varying environment remains stable when the group delay (DGD) equal to 1000ps, the system performance relative symbol frequency average (ISFA) algorithm to improve the 2.2dB, when considering the linewidth and frequency offset are more than the advantages of 0.5dB.
3. for 112Gbit/s polarization division multiplexing CO-OFDM system nonlinear problem, put forward the Baer laboratory space division encoding (BLAST) algorithm is used to improve the system of nonlinear tolerance. This paper has carried on the simulation of system performance in dispersion compensation rate under different results in dispersion compensation, 800km transmission, system performance compared the ISFA algorithm is increased by at least 5dB.
4. CO-OFDM system for wavelength division multiplexing in XPM, the correlation analysis method of isolated cross phase modulation (XPM) caused by phase noise and polarization crosstalk noise to analyze the characteristics of the system in XPM. Through this analysis method can clearly see how the system parameters affect XPM. in OFDM system. No phase recovery algorithm under the condition of phase noise compared to verify that the crosstalk noise is dominant.
5. for dense wavelength division multiplexing CO-OFDM system will link all nonlinear noise as four wave mixing (FWM) problem is proposed, because of too many hypotheses in the literature that the estimation method is not accurate enough, which has certain limitations to the application of other modulation formats. The results show that the adjustment of parameter estimation formula in this will influence the theoretical value, and the link conditions of different system parameters or conditions, the best values are different so that the theoretical and Simulation of Q value curve is consistent, show that the nonlinear effect of frequency domain estimation method is not accurate enough and not complete.
In conclusion, starting from the single channel CO-OFDM system platform, we have made a comprehensive research on the nonlinear mechanism of the system from the establishment correction to the channel estimation, the synchronization estimation, the phase noise estimation and the analysis of the WDM CO-OFDM system.

【學(xué)位授予單位】：北京郵電大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TN929.11

【參考文獻(xiàn)】

相關(guān)期刊論文 前3條

1 喬耀軍;王戰(zhàn)勝;紀(jì)越峰;;Blind frequency offset estimation based on cyclic prefix and virtual subcarriers in CO-OFDM system[J];Chinese Optics Letters;2010年09期

2 李爐焦;喬耀軍;紀(jì)越峰;;Optimized optical phase conjugation conf iguration for f iber nonlinearity compensation in CO-OFDM systems[J];Chinese Optics Letters;2011年06期

3 ;Analysis and experimentation of key technologies in service-oriented optical internet[J];Science China(Information Sciences);2011年02期

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本文編號(hào)：1480585