基于线型卡尔曼滤波器的双偏振并行载波相位恢复算法
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摘要
针对偏振复用16阶正交幅度调制(16QAM)传输系统(PDM-16QAM),基于线型卡尔曼滤波器,提出了一种计算复杂度更低、线宽容忍度更高的双偏振并行载波相位恢复算法,使用两个偏振态内环和外环的符号信息对两个偏振态同时进行相位噪声估计。仿真结果表明,在传输速率为224Gb/s传输速率下,本文算法相比于单偏振卡尔曼滤波器算法的线宽容忍度提高了7倍,由原来的400kHz提高至2800kHz。此外,相比于单偏振卡尔曼滤波器载波相位恢复算法,本文算法并行处理符号个数提升了4倍左右,有效提高了算法的实时性,但是复杂度有所降低。最后,在传输速率为224Gb/s的PDM-16QAM传输实验中对本文算法进行了验证。
A dual-polarization paralleled carrier phase recovery algorithm with better linewidth tolerance and lower computational complexity is presented for polarization division multiplexing and 16-order quadrature amplitude modulation(PDM-16 QAM)system based on linear Kalman filter(LKF).The symbols in first and third rings of two polarizations are used to perform phase noise estimation.The simulation results for PDM-16 QAM system with the transmission rate of 224 Gb/s demonstrate that the linewidth tolerance of dual-polarization LKF is about seven times of that of single-polarization LKF.The linewidth tolerance is improved to 2800 kHz from 400 kHz.The dualpolarization LKF processes about four times symbols in one block than single-polarization LKF,which reduces the algorithm computational complexity and enhances the real-time performance.Finally,the proposed algorithm is verified in the transmission experiment of PDM-16 QAM system with the transmission rate of 224 Gb/s.
A dual-polarization paralleled carrier phase recovery algorithm with better linewidth tolerance and lower computational complexity is presented for polarization division multiplexing and 16-order quadrature amplitude modulation(PDM-16 QAM)system based on linear Kalman filter(LKF).The symbols in first and third rings of two polarizations are used to perform phase noise estimation.The simulation results for PDM-16 QAM system with the transmission rate of 224 Gb/s demonstrate that the linewidth tolerance of dual-polarization LKF is about seven times of that of single-polarization LKF.The linewidth tolerance is improved to 2800 kHz from 400 kHz.The dualpolarization LKF processes about four times symbols in one block than single-polarization LKF,which reduces the algorithm computational complexity and enhances the real-time performance.Finally,the proposed algorithm is verified in the transmission experiment of PDM-16 QAM system with the transmission rate of 224 Gb/s.
引文
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[11]Dong Y J,Tang Y J,Ren H L,et al.Phase noise compensation algorithm of CO-OFDM system based on unscented Kalman filter[J].Chinese Journal of Lasers,2017,44(11):1106010.董月军,唐英杰,任宏亮,等.基于无迹卡尔曼滤波的CO-OFDM系统相位噪声补偿算法[J].中国激光,2017,44(11):1106010.
[12]Pakala L,Schmauss B.Improved decision directed carrier phase estimation for nonlinearity mitigation in16-QAM systems[C]∥2014 16th International Conference on Transparent Optical Networks(ICTON),July 6-10,2014,Graz,Austria.New York:IEEE,2014:1-4.
[13]Pakala L,Schmauss B.Joint compensation of phase and amplitude noise using extended Kalman filter in coherent QAM systems[C]∥2014 The European Conference on Optical Communication,September21-25,2014,Cannes,France.New York:IEEE,2014:1-3.
[14]Inoue T,Namiki S.Carrier recovery for M-QAMsignals based on a block estimation process with Kalman filter[J].Optics Express,2014,22(13):15376-15387.
[15]Jignesh J,Corcoran B,Lowery A.Parallelized unscented Kalman filters for carrier recovery in coherent optical communication[J].Optics Letters,2016,41(14):3253-3256.
[16]Muller R R,Mello D A D A.Phase-offset estimation for joint-polarization phase-recovery in DP-16-QAMsystems[J].IEEE Photonics Technology Letters,2010,22(20):1515-1517.
[2]Savory S J.Digital coherent optical receivers:algorithms and subsystems[J].IEEE Journal of Selected Topics in Quantum Electronics,2010,16(5):1164-1179.
[3]Savory S J.Digital filters for coherent optical receivers[J].Optics Express,2008,16(2):804-817.
[4]Pfau T,Hoffmann S,NoéR.Hardware-efficient coherent digital receiver concept with feedforward carrier recovery for M-QAM constellations[J].Journal of Lightwave Technology,2009,27(8):989-999.
[5]Gao Y L,Lau A P T,Yan S Y,et al.Lowcomplexity and phase noise tolerant carrier phase estimation for dual-polarization 16-QAM systems[J].Optics Express,2011,19(22):21717-21729.
[6]Souto D V,Olsson B E,Larsson C,et al.Jointpolarization and joint-subchannel carrier phase estimation for 16-QAM optical systems[J].Journal of Lightwave Technology,2012,30(20):3185-3191.
[7]Alfredsson A F,Krishnan R,Agrell E.Jointpolarization phase-noise estimation and symbol detection for optical coherent receivers[J].Journal of Lightwave Technology,2016,34(18):4394-4405.
[8]Lu J N,Li X,Fu S N,et al.Joint carrier phase and frequency-offset estimation with parallel implementation for dual-polarization coherent receiver[J].Optics Express,2017,25(5):5217-5231.
[9]Cao G L,Yang Y F,Wang F,et al.Extended Kalman based polarization and carrier phase quickly tracking for PDM-16QAM[J].Acta Optica Sinica,2014,34(12):1206005.曹国亮,杨彦甫,王非,等.基于扩展卡尔曼的PDM-16QAM偏振态和载波相位快速跟踪[J].光学学报,2014,34(12):1206005.
[10]Hou B J,Yang Y F,Xiang Q,et al.A joint frequency offset and phase estimation scheme based on cascaded EKF and LKF[J].Acta Optica Sinica,2018,38(1):0106004.侯冰洁,杨彦甫,向前,等.基于EKF和LKF级联的频偏和相位估计联合方案[J].光学学报,2018,38(1):0106004.
[11]Dong Y J,Tang Y J,Ren H L,et al.Phase noise compensation algorithm of CO-OFDM system based on unscented Kalman filter[J].Chinese Journal of Lasers,2017,44(11):1106010.董月军,唐英杰,任宏亮,等.基于无迹卡尔曼滤波的CO-OFDM系统相位噪声补偿算法[J].中国激光,2017,44(11):1106010.
[12]Pakala L,Schmauss B.Improved decision directed carrier phase estimation for nonlinearity mitigation in16-QAM systems[C]∥2014 16th International Conference on Transparent Optical Networks(ICTON),July 6-10,2014,Graz,Austria.New York:IEEE,2014:1-4.
[13]Pakala L,Schmauss B.Joint compensation of phase and amplitude noise using extended Kalman filter in coherent QAM systems[C]∥2014 The European Conference on Optical Communication,September21-25,2014,Cannes,France.New York:IEEE,2014:1-3.
[14]Inoue T,Namiki S.Carrier recovery for M-QAMsignals based on a block estimation process with Kalman filter[J].Optics Express,2014,22(13):15376-15387.
[15]Jignesh J,Corcoran B,Lowery A.Parallelized unscented Kalman filters for carrier recovery in coherent optical communication[J].Optics Letters,2016,41(14):3253-3256.
[16]Muller R R,Mello D A D A.Phase-offset estimation for joint-polarization phase-recovery in DP-16-QAMsystems[J].IEEE Photonics Technology Letters,2010,22(20):1515-1517.