基于卡爾曼濾波的光信號偏振態(tài)和載波恢復技術研究
發(fā)布時間：2018-11-16 18:21
【摘要】：將先進調制格式、偏振復用、相干接收、數字信號處理技術相結合是最具潛力提高下一代光通信網絡頻譜利用率以及傳輸距離的方案之一。高性能的信號處理算法可以極大改善接收機性能。本文結合當下研究熱點,圍繞基于卡爾曼濾波器的相干光接收機信號處理技術在偏振態(tài)恢復、頻偏估計以及載波相位恢復方面的應用進行了深入系統的研究,研究過程中使用仿真與實驗相結合的方法,討論了這三種應用環(huán)境中基于卡爾曼濾波的相干光接收機數字信號處理技術性能。在對偏振態(tài)恢復技術的研究中,首先在傳統的基于擴展卡爾曼濾波器的PDM-QPSK信號偏振態(tài)和載波相位同時跟蹤技術基礎上,對濾波器進行了雙測量方程的擴展,使其可以用于PDM-16QAM的偏振態(tài)和載波相位跟蹤,并分別討論了偏振態(tài)旋轉、相位噪聲、剩余頻偏、剩余色散、偏振模色散以及調優(yōu)參量等對濾波器性能的影響;其次為了解決偏振態(tài)和載波相位同時跟蹤的擴展卡爾曼濾波方法頻偏依賴的問題,本文提出一種基于半徑判決輔助的線性卡爾曼濾波器形式用于接收信號的偏振態(tài)跟蹤,對PDM-QPSK信號使用單測量方程,對PDM-16QAM信號使用雙測量方程,實驗結果表明方法具有收斂速度快,可跟蹤的偏振態(tài)旋轉速率高,運算相對簡單的優(yōu)點;隨著研究的深入,本文發(fā)現針對PDM-QPSK的線性卡爾曼偏振態(tài)跟蹤方法可以在不改變?yōu)V波器結構只需適當調整調優(yōu)參數的情況下直接應用于PDM-16QAM、PDM-64QAM甚至PDM-QPSK/16QAM混合傳輸信號的偏振態(tài)跟蹤,這意味著算法具有“全盲”特性,并且具有更小的運算復雜度。在對頻偏估計技術的研究中,在從“角逼近”和“點逼近”兩個角度研究了的基于卡爾曼濾波的頻偏估計技術,并在基于訓練序列去除調制相位和基于M-th power去除調制相位兩種情況下討論了算法的性能,最后將以上四種卡爾曼濾波方法與傳統的ViterbiViterbi方法以及Morelli頻域峰值法進行了性能對比。在對載波相位恢復技術的研究中,本文研究了QPSK信號和16QAM信號的卡爾曼濾波載波相位恢復方法,仿真結果表明對于16QAM信號來說,雙方程結構具有比單方程結構高的估計精度。最后本文討論了QPSK信號和16QAM信號下卡爾曼濾波器的載波相位恢復精度和線寬容忍性。本文結果對于卡爾曼濾波器在相干光接收機數字信號處理技術中的應用具有較強推動作用和實際意義,對卡爾曼濾波器在偏振態(tài)恢復、頻偏估計以及載波相位恢復三種應用中的性能提供了實際參考。
[Abstract]:The combination of advanced modulation format, polarization multiplexing, coherent reception and digital signal processing is one of the most promising schemes to improve the spectrum efficiency and transmission distance of the next generation optical communication network. High performance signal processing algorithm can greatly improve receiver performance. Combined with the current research focus, this paper focuses on the application of coherent optical receiver signal processing technology based on Kalman filter in polarization state recovery, frequency offset estimation and carrier phase recovery. The digital signal processing performance of coherent optical receiver based on Kalman filter in these three application environments is discussed by combining simulation and experiment. In the research of polarization recovery technology, firstly, based on the traditional polarization state and carrier phase tracking technology of PDM-QPSK signal based on extended Kalman filter, the dual measurement equation is extended. The effects of polarization rotation, phase noise, residual frequency offset, residual dispersion, polarization mode dispersion and tuning parameters on the filter performance are discussed. Secondly, in order to solve the problem of frequency offset dependence of extended Kalman filter with polarization state and carrier phase tracking simultaneously, a linear Kalman filter based on radius decision is proposed for polarization tracking of received signals. Single measurement equation is used for PDM-QPSK signal and double measurement equation is used for PDM-16QAM signal. The experimental results show that the method has the advantages of fast convergence, high tracking polarization rotation rate and relatively simple operation. With the development of the research, it is found that the linear Kalman polarization tracking method for PDM-QPSK can be directly applied to PDM-16QAM, without changing the filter structure and only adjusting the tuning parameters properly. Polarization tracking of PDM-64QAM or even PDM-QPSK/16QAM hybrid signals means that the algorithm is "all-blind" and has less computational complexity. In the research of frequency offset estimation technology, the frequency offset estimation technology based on Kalman filter is studied from angle approximation and point approximation. The performance of the algorithm is discussed in two cases: the modulation phase is removed based on training sequence and the modulation phase is removed based on M-th power. Finally, the performance of the above four Kalman filtering methods is compared with the traditional ViterbiViterbi method and the Morelli frequency domain peak value method. In the research of carrier phase recovery technique, the Kalman filter method of QPSK signal and 16QAM signal is studied in this paper. The simulation results show that the double equation structure has higher estimation accuracy than the single equation structure for 16QAM signal. Finally, the carrier phase recovery accuracy and linewidth tolerance of Kalman filter in QPSK signal and 16QAM signal are discussed. The results in this paper have a strong impetus and practical significance for the application of Kalman filter in the digital signal processing technology of coherent optical receiver, and it is also useful for the polarization recovery of Kalman filter. The performance of frequency offset estimation and carrier phase recovery provides practical reference.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN713;TN911.7
本文編號：2336272
[Abstract]:The combination of advanced modulation format, polarization multiplexing, coherent reception and digital signal processing is one of the most promising schemes to improve the spectrum efficiency and transmission distance of the next generation optical communication network. High performance signal processing algorithm can greatly improve receiver performance. Combined with the current research focus, this paper focuses on the application of coherent optical receiver signal processing technology based on Kalman filter in polarization state recovery, frequency offset estimation and carrier phase recovery. The digital signal processing performance of coherent optical receiver based on Kalman filter in these three application environments is discussed by combining simulation and experiment. In the research of polarization recovery technology, firstly, based on the traditional polarization state and carrier phase tracking technology of PDM-QPSK signal based on extended Kalman filter, the dual measurement equation is extended. The effects of polarization rotation, phase noise, residual frequency offset, residual dispersion, polarization mode dispersion and tuning parameters on the filter performance are discussed. Secondly, in order to solve the problem of frequency offset dependence of extended Kalman filter with polarization state and carrier phase tracking simultaneously, a linear Kalman filter based on radius decision is proposed for polarization tracking of received signals. Single measurement equation is used for PDM-QPSK signal and double measurement equation is used for PDM-16QAM signal. The experimental results show that the method has the advantages of fast convergence, high tracking polarization rotation rate and relatively simple operation. With the development of the research, it is found that the linear Kalman polarization tracking method for PDM-QPSK can be directly applied to PDM-16QAM, without changing the filter structure and only adjusting the tuning parameters properly. Polarization tracking of PDM-64QAM or even PDM-QPSK/16QAM hybrid signals means that the algorithm is "all-blind" and has less computational complexity. In the research of frequency offset estimation technology, the frequency offset estimation technology based on Kalman filter is studied from angle approximation and point approximation. The performance of the algorithm is discussed in two cases: the modulation phase is removed based on training sequence and the modulation phase is removed based on M-th power. Finally, the performance of the above four Kalman filtering methods is compared with the traditional ViterbiViterbi method and the Morelli frequency domain peak value method. In the research of carrier phase recovery technique, the Kalman filter method of QPSK signal and 16QAM signal is studied in this paper. The simulation results show that the double equation structure has higher estimation accuracy than the single equation structure for 16QAM signal. Finally, the carrier phase recovery accuracy and linewidth tolerance of Kalman filter in QPSK signal and 16QAM signal are discussed. The results in this paper have a strong impetus and practical significance for the application of Kalman filter in the digital signal processing technology of coherent optical receiver, and it is also useful for the polarization recovery of Kalman filter. The performance of frequency offset estimation and carrier phase recovery provides practical reference.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN713;TN911.7
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