Marvell Asia Pte., Ltd.

Mario Rafael Hueda

Nestor D Campos

Matias German Schnidrig

Mario Alejandro Castrillion

Damian Alfonso Morero

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.

Optical receiver including constrained frequency-domain circuitry with adaptive equalization

A decoder for a receiver in a communication system includes an interface configured to receive encoded input data via a communication channel. The encoded input data includes forward error correction (FEC) codewords. A processor is configured to decode the FEC codewords using low density parity check (LDPC) codes defined by a parity check matrix. The parity check matrix is defined by both regular column partition (RCP) constraints and quasi-cyclic (QC) constraints. An output circuit is configured to output a decoded codeword based on the FEC codewords decoded by the processor.

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Santa Clara, CA, United States of America

Mario Rafael Hueda