Improved Decoding of Quantum Tanner Codes Using Generalized Check Nodes

Fuente: arXiv
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Auteurs principaux: Mostad, Olai Å., Rosnes, Eirik, Lin, Hsuan-Yin
Format: Preprint
Publié: 2026
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author Mostad, Olai Å.
Rosnes, Eirik
Lin, Hsuan-Yin
author_facet Mostad, Olai Å.
Rosnes, Eirik
Lin, Hsuan-Yin
contents We study the decoding problem for quantum Tanner codes and propose to exploit the underlying local code structure by grouping check nodes into more powerful generalized check nodes for enhanced iterative belief propagation (BP) decoding by decoding the generalized checks using a maximum a posteriori (MAP) decoder as part of the check node processing of each decoding iteration. We mainly study the finite-length setting and show that the proposed enhanced generalized BP decoder for quantum Tanner codes significantly outperforms the standard quaternary BP decoder with memory effects, as well as the recently proposed Relay-BP decoder, even outperforming generalized bicycle (GB) codes with comparable parameters in some cases. For other classes of quantum low-density parity-check (qLDPC) codes, we propose a greedy algorithm to combine checks for generalized BP decoding. However, for GB codes, bivariate bicycle codes, hypergraph product codes, and lifted-product codes, there seems to be limited gain by combining simple checks into more powerful ones. To back up our findings, we also provide a theoretical cycle analysis for the considered qLDPC codes.
format Preprint
id arxiv_https___arxiv_org_abs_2603_05486
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Improved Decoding of Quantum Tanner Codes Using Generalized Check Nodes
Mostad, Olai Å.
Rosnes, Eirik
Lin, Hsuan-Yin
Quantum Physics
Information Theory
We study the decoding problem for quantum Tanner codes and propose to exploit the underlying local code structure by grouping check nodes into more powerful generalized check nodes for enhanced iterative belief propagation (BP) decoding by decoding the generalized checks using a maximum a posteriori (MAP) decoder as part of the check node processing of each decoding iteration. We mainly study the finite-length setting and show that the proposed enhanced generalized BP decoder for quantum Tanner codes significantly outperforms the standard quaternary BP decoder with memory effects, as well as the recently proposed Relay-BP decoder, even outperforming generalized bicycle (GB) codes with comparable parameters in some cases. For other classes of quantum low-density parity-check (qLDPC) codes, we propose a greedy algorithm to combine checks for generalized BP decoding. However, for GB codes, bivariate bicycle codes, hypergraph product codes, and lifted-product codes, there seems to be limited gain by combining simple checks into more powerful ones. To back up our findings, we also provide a theoretical cycle analysis for the considered qLDPC codes.
title Improved Decoding of Quantum Tanner Codes Using Generalized Check Nodes
topic Quantum Physics
Information Theory
url https://arxiv.org/abs/2603.05486