# Improved Decoding of Staircase Codes: The Soft-aided Bit-marking (SABM) Algorithm

## TL;DR

This paper introduces a soft-aided bit-marking (SABM) decoding algorithm for staircase codes that leverages soft information to enhance decoding performance with minimal complexity increase.

## Contribution

The paper proposes a novel SABM decoding algorithm that partially uses soft information to improve staircase code decoding, achieving significant performance gains with low additional complexity.

## Key findings

- Up to 0.30 dB gain at BER of 10^{-7} for SCCs with 2-error-correcting BCH codes.
- Almost half of the ideal decoder gain is achieved.
- Complexity increase is only around 4% at BER of 10^{-4}.

## Abstract

Staircase codes (SCCs) are typically decoded using iterative bounded-distance decoding (BDD) and hard decisions. In this paper, a novel decoding algorithm is proposed, which partially uses soft information from the channel. The proposed algorithm is based on marking certain number of highly reliable and highly unreliable bits. These marked bits are used to improve the miscorrection-detection capability of the SCC decoder and the error-correcting capability of BDD. For SCCs with $2$-error-correcting Bose-Chaudhuri-Hocquenghem component codes, our algorithm improves upon standard SCC decoding by up to $0.30$~dB at a bit-error rate (BER) of $10^{-7}$. The proposed algorithm is shown to achieve almost half of the gain achievable by an idealized decoder with this structure. A complexity analysis based on the number of additional calls to the component BDD decoder shows that the relative complexity increase is only around $4\%$ at a BER of $10^{-4}$. This additional complexity is shown to decrease as the channel quality improves. Our algorithm is also extended (with minor modifications) to product codes. The simulation results show that in this case, the algorithm offers gains of up to $0.44$~dB at a BER of $10^{-8}$.