Replacing the Soft FEC Limit Paradigm in the Design of Optical Communication Systems

Fuente: arXiv
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Autori principali: Alvarado, Alex, Agrell, Erik, Lavery, Domanic, Maher, Robert, Bayvel, Polina
Natura: Preprint
Pubblicazione: 2015
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author Alvarado, Alex
Agrell, Erik
Lavery, Domanic
Maher, Robert
Bayvel, Polina
author_facet Alvarado, Alex
Agrell, Erik
Lavery, Domanic
Maher, Robert
Bayvel, Polina
contents The FEC limit paradigm is the prevalent practice for designing optical communication systems to attain a certain bit-error rate (BER) without forward error correction (FEC). This practice assumes that there is an FEC code that will reduce the BER after decoding to the desired level. In this paper, we challenge this practice and show that the concept of a channel-independent FEC limit is invalid for soft-decision bit-wise decoding. It is shown that for low code rates and high order modulation formats, the use of the soft FEC limit paradigm can underestimate the spectral efficiencies by up to 20%. A better predictor for the BER after decoding is the generalized mutual information, which is shown to give consistent post-FEC BER predictions across different channel conditions and modulation formats. Extensive optical full-field simulations and experiments are carried out in both the linear and nonlinear transmission regimes to confirm the theoretical analysis.
format Preprint
id arxiv_https___arxiv_org_abs_1503_05477
institution arXiv
publishDate 2015
record_format arxiv
spellingShingle Replacing the Soft FEC Limit Paradigm in the Design of Optical Communication Systems
Alvarado, Alex
Agrell, Erik
Lavery, Domanic
Maher, Robert
Bayvel, Polina
Information Theory
Optics
The FEC limit paradigm is the prevalent practice for designing optical communication systems to attain a certain bit-error rate (BER) without forward error correction (FEC). This practice assumes that there is an FEC code that will reduce the BER after decoding to the desired level. In this paper, we challenge this practice and show that the concept of a channel-independent FEC limit is invalid for soft-decision bit-wise decoding. It is shown that for low code rates and high order modulation formats, the use of the soft FEC limit paradigm can underestimate the spectral efficiencies by up to 20%. A better predictor for the BER after decoding is the generalized mutual information, which is shown to give consistent post-FEC BER predictions across different channel conditions and modulation formats. Extensive optical full-field simulations and experiments are carried out in both the linear and nonlinear transmission regimes to confirm the theoretical analysis.
title Replacing the Soft FEC Limit Paradigm in the Design of Optical Communication Systems
topic Information Theory
Optics
url https://arxiv.org/abs/1503.05477