CO-OFDM系統(tǒng)中相位噪聲的理論和實(shí)驗(yàn)研究
發(fā)布時(shí)間：2018-11-28 18:07
【摘要】：正交頻分復(fù)用技術(shù)以其較強(qiáng)的色散容忍度等優(yōu)勢而成為了下一代高速光傳輸系統(tǒng)中的一種非常有潛力的核心技術(shù)。現(xiàn)階段有兩種主要的光正交頻分復(fù)用技術(shù)：直接探測(?)OFDM技術(shù)和相干探測(?)OFDM技術(shù),其中相干探鋇(?)OFDM已經(jīng)被廣泛應(yīng)用于長距離光纖通信網(wǎng)絡(luò)。和直接探測(?)OFDM技術(shù)相比,相干OFDM技術(shù)有著許多的優(yōu)勢。這篇論文的目的就是從理論和實(shí)驗(yàn)上探討一種長距離光傳輸系統(tǒng)中相干OFDM技術(shù)中的相位噪聲抖動(dòng)補(bǔ)償理論得益于高效的數(shù)字信號處理技術(shù),相干光OFDM接收技術(shù)使得物理層的損傷補(bǔ)償變得可能,這些損傷包括光色度色散、偏振模色散、本振相位噪聲和采樣時(shí)鐘抖動(dòng)。后面兩個(gè)損傷都是造成相位噪聲抖動(dòng)的主要原因。其中,采樣時(shí)鐘抖動(dòng)是用來描述在數(shù)模轉(zhuǎn)換器中采樣時(shí)鐘的誤差導(dǎo)致的相位噪聲。而本地振蕩器的相位噪聲則是由于發(fā)射端激光器和接收端激光器的隨機(jī)時(shí)鐘抖動(dòng)而產(chǎn)生的。理論研究表明本振光的相位噪聲和采樣時(shí)鐘誤差會(huì)相互轉(zhuǎn)換,因此能夠很方便地設(shè)計(jì)出滿足設(shè)計(jì)初衷的最佳系統(tǒng)和數(shù)據(jù)轉(zhuǎn)換效率。基于導(dǎo)頻設(shè)計(jì)和前向最大似然估計(jì)方法,本論文提出了一種新型相位噪聲抖動(dòng)的補(bǔ)償算法。仿真結(jié)果表明,本振光的線寬直接影響著接收端信號的質(zhì)量,而且相比較而言,4QAM有著比16QAM,256QAM信號更好的傳輸性能。為了進(jìn)一步提高接收機(jī)的性能,我們在同步機(jī)制中引入了MMSE算法。仿真也證明,在基于導(dǎo)頻的前向最大似然估計(jì)(PA-FF-ML)算法中使用MMSE算法可以獲得比直接使用簡單的PA-FF-ML算法更好的傳輸性能。本論文通過仿真建立了RMSE算法中導(dǎo)頻符號的數(shù)量和濾波器的抽頭數(shù)量的關(guān)系。此外,本論文還搭建了OFDM系統(tǒng)實(shí)驗(yàn)驗(yàn)證平臺(tái)并證明了仿真結(jié)果的正確性。在沒有使用任何色散補(bǔ)償技術(shù)的前提下,本論文成功將速率為10Gbps的16QAM-OFDM信號傳輸了25公里長的單模光纖,并獲得了非常好的傳輸性能.
[Abstract]:Orthogonal Frequency Division Multiplexing (OFDM) technology has become a potential core technology in the next generation of high-speed optical transmission systems due to its strong dispersion tolerance and other advantages. At present, there are two main optical orthogonal frequency division multiplexing techniques: direct detection (?) OFDM and coherent detection (?) OFDM, in which barium (?) OFDM has been widely used in long distance optical fiber communication networks. Compared with direct detection (?) OFDM technology, coherent OFDM technology has many advantages. The purpose of this paper is to discuss theoretically and experimentally a theory of phase noise jitter compensation in coherent OFDM technology for long distance optical transmission systems, which benefits from the efficient digital signal processing technology. Coherent optical OFDM reception makes it possible to compensate for damage in the physical layer, including chromatic dispersion, polarization mode dispersion, local oscillator phase noise and sampling clock jitter. The latter two injuries are the main cause of phase noise jitter. Sampling clock jitter is used to describe phase noise caused by sampling clock error in DAC. The phase noise of the local oscillator is caused by the random clock jitter of the transmitter laser and the receiver laser. The theoretical study shows that the phase noise and sampling clock errors of the local oscillator can be converted to each other, so it is convenient to design the optimal system and data conversion efficiency to meet the original purpose of the design. Based on pilot design and forward maximum likelihood estimation, a novel phase noise jitter compensation algorithm is proposed in this paper. The simulation results show that the linewidth of the local oscillator directly affects the quality of the receiver signal, and 4QAM has better transmission performance than the 16QAM 256QAM signal. In order to further improve the performance of the receiver, we introduce the MMSE algorithm into the synchronization mechanism. Simulation results also show that using MMSE algorithm in pilot-based forward maximum likelihood estimation (PA-FF-ML) algorithm can achieve better transmission performance than direct use of simple PA-FF-ML algorithm. In this paper, the relationship between the number of pilot symbols and the number of tap of filter in RMSE algorithm is established by simulation. In addition, the OFDM system experimental verification platform is built and the correctness of the simulation results is proved. Without using any dispersion compensation technique, the 16QAM-OFDM signal at the rate of 10Gbps has been successfully transmitted to a single mode fiber with a length of 25 km and a very good transmission performance has been obtained in this paper.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TN929.53
本文編號：2363815
[Abstract]:Orthogonal Frequency Division Multiplexing (OFDM) technology has become a potential core technology in the next generation of high-speed optical transmission systems due to its strong dispersion tolerance and other advantages. At present, there are two main optical orthogonal frequency division multiplexing techniques: direct detection (?) OFDM and coherent detection (?) OFDM, in which barium (?) OFDM has been widely used in long distance optical fiber communication networks. Compared with direct detection (?) OFDM technology, coherent OFDM technology has many advantages. The purpose of this paper is to discuss theoretically and experimentally a theory of phase noise jitter compensation in coherent OFDM technology for long distance optical transmission systems, which benefits from the efficient digital signal processing technology. Coherent optical OFDM reception makes it possible to compensate for damage in the physical layer, including chromatic dispersion, polarization mode dispersion, local oscillator phase noise and sampling clock jitter. The latter two injuries are the main cause of phase noise jitter. Sampling clock jitter is used to describe phase noise caused by sampling clock error in DAC. The phase noise of the local oscillator is caused by the random clock jitter of the transmitter laser and the receiver laser. The theoretical study shows that the phase noise and sampling clock errors of the local oscillator can be converted to each other, so it is convenient to design the optimal system and data conversion efficiency to meet the original purpose of the design. Based on pilot design and forward maximum likelihood estimation, a novel phase noise jitter compensation algorithm is proposed in this paper. The simulation results show that the linewidth of the local oscillator directly affects the quality of the receiver signal, and 4QAM has better transmission performance than the 16QAM 256QAM signal. In order to further improve the performance of the receiver, we introduce the MMSE algorithm into the synchronization mechanism. Simulation results also show that using MMSE algorithm in pilot-based forward maximum likelihood estimation (PA-FF-ML) algorithm can achieve better transmission performance than direct use of simple PA-FF-ML algorithm. In this paper, the relationship between the number of pilot symbols and the number of tap of filter in RMSE algorithm is established by simulation. In addition, the OFDM system experimental verification platform is built and the correctness of the simulation results is proved. Without using any dispersion compensation technique, the 16QAM-OFDM signal at the rate of 10Gbps has been successfully transmitted to a single mode fiber with a length of 25 km and a very good transmission performance has been obtained in this paper.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TN929.53
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 吳毅凌;李巨浩;趙春旭;趙玉萍;張帆;陳章淵;;Coherent optical OFDM scheme with inter-carrier interference self-cancellation and common phase error compensation[J];Chinese Optics Letters;2010年07期
，本文編號：2363815
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