Post-FEC BER Benchmarking for Bit-Interleaved Coded Modulation with Probabilistic Shaping

Fuente: arXiv
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Main Authors: Yoshida, Tsuyoshi, Alvarado, Alex, Karlsson, Magnus, Agrell, Erik
Format: Preprint
Published: 2019
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author Yoshida, Tsuyoshi
Alvarado, Alex
Karlsson, Magnus
Agrell, Erik
author_facet Yoshida, Tsuyoshi
Alvarado, Alex
Karlsson, Magnus
Agrell, Erik
contents Accurate performance benchmarking after forward error correction (FEC) decoding is essential for system design in optical fiber communications. Generalized mutual information (GMI) has been shown to be successful at benchmarking the bit-error rate (BER) after FEC decoding (post-FEC BER) for systems with soft-decision (SD) FEC without probabilistic shaping (PS). However, GMI is not relevant to benchmark post-FEC BER for systems with SD-FEC and PS. For such systems, normalized GMI (NGMI), asymmetric information (ASI), and achievable FEC rate have been proposed instead. They are good at benchmarking post-FEC BER or to give an FEC limit in bit-interleaved coded modulation (BICM) with PS, but their relation has not been clearly explained so far. In this paper, we define generalized L-values under mismatched decoding, which are connected to the GMI and ASI. We then show that NGMI, ASI, and achievable FEC rate are theoretically equal under matched decoding but not under mismatched decoding. We also examine BER before FEC decoding (pre-FEC BER) and ASI over Gaussian and nonlinear fiber-optic channels with approximately matched decoding. ASI always shows better correlation with post-FEC BER than pre-FEC BER for BICM with PS. On the other hand, post-FEC BER can differ at a given ASI when we change the bit mapping, which describes how each bit in a codeword is assigned to a bit tributary.
format Preprint
id arxiv_https___arxiv_org_abs_1911_01585
institution arXiv
publishDate 2019
record_format arxiv
spellingShingle Post-FEC BER Benchmarking for Bit-Interleaved Coded Modulation with Probabilistic Shaping
Yoshida, Tsuyoshi
Alvarado, Alex
Karlsson, Magnus
Agrell, Erik
Signal Processing
Information Theory
Accurate performance benchmarking after forward error correction (FEC) decoding is essential for system design in optical fiber communications. Generalized mutual information (GMI) has been shown to be successful at benchmarking the bit-error rate (BER) after FEC decoding (post-FEC BER) for systems with soft-decision (SD) FEC without probabilistic shaping (PS). However, GMI is not relevant to benchmark post-FEC BER for systems with SD-FEC and PS. For such systems, normalized GMI (NGMI), asymmetric information (ASI), and achievable FEC rate have been proposed instead. They are good at benchmarking post-FEC BER or to give an FEC limit in bit-interleaved coded modulation (BICM) with PS, but their relation has not been clearly explained so far. In this paper, we define generalized L-values under mismatched decoding, which are connected to the GMI and ASI. We then show that NGMI, ASI, and achievable FEC rate are theoretically equal under matched decoding but not under mismatched decoding. We also examine BER before FEC decoding (pre-FEC BER) and ASI over Gaussian and nonlinear fiber-optic channels with approximately matched decoding. ASI always shows better correlation with post-FEC BER than pre-FEC BER for BICM with PS. On the other hand, post-FEC BER can differ at a given ASI when we change the bit mapping, which describes how each bit in a codeword is assigned to a bit tributary.
title Post-FEC BER Benchmarking for Bit-Interleaved Coded Modulation with Probabilistic Shaping
topic Signal Processing
Information Theory
url https://arxiv.org/abs/1911.01585