Post-FEC BER Benchmarking for Bit-Interleaved Coded Modulation With Probabilistic Shaping
Journal article, 2020

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 article, 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.

Probabilistic logic

forward error correction

Decoding

probabilistic shaping

modulation

Bit error rate

Measurement

mutual information

Interleaved codes

Forward error correction

generalized mutual information

optical fiber communication

Benchmark testing

bit-interleaved coded modulation

bitwise decoding

Author

Tsuyoshi Yoshida

Osaka University

Alex Alvarado

Eindhoven University of Technology

Magnus Karlsson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Erik Agrell

Chalmers, Electrical Engineering, Communication and Antenna Systems, Communication Systems

Journal of Lightwave Technology

0733-8724 (ISSN)

Vol. 38 16 4292-4306

Subject Categories

Computer Engineering

Telecommunications

Other Engineering and Technologies not elsewhere specified

DOI

10.1109/JLT.2020.2990620

More information

Latest update

10/13/2020