Blind and low-complexity modulation format identification scheme using principal component analysis of Stokes parameters for elastic optical networks

Abstract

We propose a blind and low-complexity modulation format identification (MFI) scheme for elastic optical networks (EONs). Since the square operation reduces half the number of the clusters in Stokes space, the scheme directly performs principal component analysis (PCA) on Stokes parameters after square operation. This greatly reduces the dimensionality of received signals from 3 × N to 3 × 3. Subsequently, three obtained principal components (PCs) are employed synthetically to identify the modulation formats. The effectiveness is first verified through 28 GBaud polarization division multiplexing (PDM)-BPSK/-QPSK/-8QAM/-16QAM/-32QAM/-64QAM simulation systems. Only using 2048 symbols, the required minimum optical signal-to-noise ratio (OSNR) values to achieve 100% MFI success rate are all equal to or lower than their corresponding 7% forward error correction (FEC) thresholds. Besides that, the scheme also obtains significant tolerances to residual chromatic dispersion (CD) and differential group delay (DGD). Finally, the proposed scheme is further verified by 20 GBaud PDM-QPSK/-16QAM/-32QAM long-haul transmission experiments. The results demonstrate that the scheme exhibits good resilience towards fiber nonlinear impairments. More importantly, compared with other four kinds of MFI schemes, the used symbol number to achieve 100% MFI success rate notably equals to at most 2/5 as that of other schemes, and its time complexity can be reduced to O(N).

Low-Complexity Modulation Format Identification Based on Amplitude Histogram Distributions for Digital Coherent Receivers

“…By making use of incoming signals identical to those presented above, the performance of the proposed scheme was further evaluated in comparison with schemes using DNN, SVM, modified particle swarm optimization (M-PSO) [20] and principal component analysis of Stokes parameters (PCASP) [8]. The SVM and DNN schemes also adopted the amplitude histogram as the proposed scheme.…”

“…The use of MFI techniques would eliminate the transmissions of signal modulation format information between the transceivers, thus considerably reducing unwanted overhead. The MFI algorithm could be applied before modulation format-dependent algorithms, including polarization demultiplexing, frequency offset compensation and carrier phase recovery [8], ensuring optimal system performance.…”

“…The previously-reported MFI schemes for optical fiber communications were roughly classified into the following three categories: (1) data-aided schemes [9][10][11], in which additional pilot information is introduced and the computational complexity of the MFI scheme is low (at the cost of reduced spectral efficiency); (2) schemes based on Stokes space [7,8,[12][13][14][15][16][17][18][19][20][21][22][23], which are not sensitive to carrier phase noise, frequency offset or polarization mixing; (3) schemes based on signal characteristics arising from constant modulus algorithm (CMA) equalization [24][25][26][27][28][29][30][31][32][33], which are based on CMA-equalized signals and do not require any space mapping. Meanwhile, CMA can also compensate for residual chromatic dispersion (CD) and polarization mode dispersion (PMD).…”

Machine Learning-Aided Optical Performance Monitoring Techniques: A Review

“…PCA was used in Xu et al (2020) to identify the MF of 6 formats (BPSK,QPSK,8,16,32 and 64 QAM). 3 PC's were extracted from 2048 symbols of the stokes parameters from the received signals of a coherent receiver with OSNR varied from 8 to 40 dB and used as a reference database.…”

Modulation Format Identification Using Graph-Based 2D Stokes Plane Analysis for Elastic Optical Network

“…method [24], principal component analysis and singular value decomposition algorithm [25]. For the review of MFI researches above, compared with the decision-parameter based type and aided information based type, machine learning based algorithms have attracted significant attentions with the advantage of flexible and high-performance.…”