CO-OFDM系统中相位噪声的理论和实验研究
发布时间：2018-11-28 18:07
【摘要】：正交频分复用技术以其较强的色散容忍度等优势而成为了下一代高速光传输系统中的一种非常有潜力的核心技术。现阶段有两种主要的光正交频分复用技术：直接探测(?)OFDM技术和相干探测(?)OFDM技术,其中相干探钡(?)OFDM已经被广泛应用于长距离光纤通信网络。和直接探测(?)OFDM技术相比,相干OFDM技术有着许多的优势。这篇论文的目的就是从理论和实验上探讨一种长距离光传输系统中相干OFDM技术中的相位噪声抖动补偿理论得益于高效的数字信号处理技术,相干光OFDM接收技术使得物理层的损伤补偿变得可能,这些损伤包括光色度色散、偏振模色散、本振相位噪声和采样时钟抖动。后面两个损伤都是造成相位噪声抖动的主要原因。其中,采样时钟抖动是用来描述在数模转换器中采样时钟的误差导致的相位噪声。而本地振荡器的相位噪声则是由于发射端激光器和接收端激光器的随机时钟抖动而产生的。理论研究表明本振光的相位噪声和采样时钟误差会相互转换,因此能够很方便地设计出满足设计初衷的最佳系统和数据转换效率。基于导频设计和前向最大似然估计方法,本论文提出了一种新型相位噪声抖动的补偿算法。仿真结果表明,本振光的线宽直接影响着接收端信号的质量,而且相比较而言,4QAM有着比16QAM,256QAM信号更好的传输性能。为了进一步提高接收机的性能,我们在同步机制中引入了MMSE算法。仿真也证明,在基于导频的前向最大似然估计(PA-FF-ML)算法中使用MMSE算法可以获得比直接使用简单的PA-FF-ML算法更好的传输性能。本论文通过仿真建立了RMSE算法中导频符号的数量和滤波器的抽头数量的关系。此外,本论文还搭建了OFDM系统实验验证平台并证明了仿真结果的正确性。在没有使用任何色散补偿技术的前提下,本论文成功将速率为10Gbps的16QAM-OFDM信号传输了25公里长的单模光纤,并获得了非常好的传输性能.
[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.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN929.53
本文编号：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.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN929.53
【参考文献】
相关期刊论文 前1条
1 吴毅凌;李巨浩;赵春旭;赵玉萍;张帆;陈章渊;;Coherent optical OFDM scheme with inter-carrier interference self-cancellation and common phase error compensation[J];Chinese Optics Letters;2010年07期
，本文编号：2363815
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