公开(公告)号：US11996896B2

公开(公告)日：2024-05-28

申请号：US17558236

申请日：2021-12-21

Applicant: Marvell Asia Pte, Ltd.

Inventor： Mario Rafael Hueda ,  Nestor D. Campos

IPC: H04B10/61 ,  H04B10/079 ,  H04B10/40 ,  H04L1/00 ,  H04L7/00 ,  H04L25/03 ,  H04L27/26

CPC classification number: H04B10/6162 ,  H04B10/079 ,  H04B10/615 ,  H04B10/616 ,  H04B10/6161 ,  H04B10/6165 ,  H04L1/0045 ,  H04L7/0075 ,  H04L25/03019 ,  H04L25/03159 ,  H04L27/2662 ,  H04L27/2697 ,  H04B10/40 ,  H04L27/2634

Abstract: A method and structure for equalization in coherent optical receivers. Block-based LMS (BLMS) algorithm is one of the many efficient adaptive equalization algorithms used to (i) increase convergence speed and (ii) reduce implementation complexity. Since the computation of the equalizer output and the gradient of the error are obtained using a linear convolution, BLMS can be efficiently implemented in the frequency domain with the constrained frequency-domain BLMS (FBLMS) adaptive algorithm. The present invention introduces a novel reduced complexity constrained FBLMS algorithm. This new approach replaces the two discrete Fourier transform (DFT) stages required to evaluate the DFT of the gradient error, by a simple frequency domain filtering. Implementation complexity can be drastically reduced in comparison to the standard constrained FBLMS. Furthermore, the new approach achieves better performance than that obtained with the unconstrained FBLMS in ultra-high speed coherent optical receivers.

公开(公告)号：US11212009B2

公开(公告)日：2021-12-28

申请号：US16808055

申请日：2020-03-03

Applicant: Marvell Asia Pte. Ltd.

Inventor： Mario Rafael Hueda ,  Nestor D. Campos

IPC: H04B10/61 ,  H04L25/03 ,  H04L7/00 ,  H04L27/26 ,  H04B10/079 ,  H04L1/00 ,  H04B10/40

Abstract: A method and structure for equalization in coherent optical receivers. Block-based LMS (BLMS) algorithm is one of the many efficient adaptive equalization algorithms used to (i) increase convergence speed and (ii) reduce implementation complexity. Since the computation of the equalizer output and the gradient of the error are obtained using a linear convolution, BLMS can be efficiently implemented in the frequency domain with the constrained frequency-domain BLMS (FBLMS) adaptive algorithm. The present invention introduces a novel reduced complexity constrained FBLMS algorithm. This new approach replaces the two discrete Fourier transform (DFT) stages required to evaluate the DFT of the gradient error, by a simple frequency domain filtering. Implementation complexity can be drastically reduced in comparison to the standard constrained FBLMS. Furthermore, the new approach achieves better performance than that obtained with the unconstrained FBLMS in ultra-high speed coherent optical receivers.