Improving soft FEC performance for higher-order modulations via optimized bit channel mappings
Artikel i vetenskaplig tidskrift, 2014

Soft forward error correction with higher-order modulations is often implemented in practice via the pragmatic bit-interleaved coded modulation paradigm, where a single binary code is mapped to a nonbinary modulation. In this paper, we study the optimization of the mapping of the coded bits to the modulation bits for a polarization-multiplexed fiber-optical system without optical inline dispersion compensation. Our focus is on protograph-based low-density parity-check (LDPC) codes which allow for an efficient hardware implementation, suitable for high-speed optical communications. The optimization is applied to the AR4JA protograph family, and further extended to protograph-based spatially coupled LDPC codes assuming a windowed decoder. Full field simulations via the split-step Fourier method are used to verify the analysis. The results show performance gains of up to 0.25 dB, which translate into a possible extension of the transmission reach by roughly up to 8%, without significantly increasing the system complexity.

optimization

coded modulation

interleaver

BICM

Bit mapper

spatially coupled

mapping

higher-order modulations

LDPC code

Författare

Christian Häger

Signaler och system, Kommunikationssystem, informationsteori och antenner, Kommunikationssystem

Alexandre Graell i Amat

Signaler och system, Kommunikationssystem, informationsteori och antenner, Kommunikationssystem

Fredrik Brännström

Signaler och system, Kommunikationssystem, informationsteori och antenner, Kommunikationssystem

Alex Alvarado

University College London (UCL)

Erik Agrell

Signaler och system, Kommunikationssystem, informationsteori och antenner, Kommunikationssystem

Optics Express

1094-4087 (ISSN)

Vol. 22 14544-14558

Styrkeområden

Informations- och kommunikationsteknik

Ämneskategorier

Telekommunikation

Kommunikationssystem

Infrastruktur

C3SE (Chalmers Centre for Computational Science and Engineering)

DOI

10.1364/OE.22.014544