Fully Parallelized BP Decoding for Quantum LDPC Codes Can Outperform BP-OSD

Fuente: arXiv
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Main Authors: Wang, Ming, Li, Ang, Mueller, Frank
Format: Preprint
Published: 2025
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author Wang, Ming
Li, Ang
Mueller, Frank
author_facet Wang, Ming
Li, Ang
Mueller, Frank
contents This work presents a hardware-efficient and fully parallelizable decoder for quantum LDPC codes that leverages belief propagation (BP) with a speculative post-processing strategy inspired by classical Chase decoding algorithm. By monitoring bit-level oscillation patterns during BP, our method identifies unreliable bits and generates multiple candidate vectors to selectively flip syndromes. Each modified syndrome is then decoded independently using short-depth BP, a process we refer to as BP-SF (syndrome flip). This design eliminates the need for costly Gaussian elimination used in the current BP-OSD approaches. Our implementation achieves logical error rates comparable to or better than BP-OSD while offering significantly lower latency due to its high degree of parallelism for a variety of bivariate bicycle codes. Evaluation on the [[144,12,12]] bivariate bicycle code shows that the proposed decoder reduces average latency to approximately $70\%$ of BP-OSD. When post-processing is parallelized the average latency is reduced by $55\%$ compared to the single process implementation, with the maximum latency reaching as low as $18\%$. These advantages make it particularly well-suited for real-time and resource-constrained quantum error correction systems.
format Preprint
id arxiv_https___arxiv_org_abs_2507_00254
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fully Parallelized BP Decoding for Quantum LDPC Codes Can Outperform BP-OSD
Wang, Ming
Li, Ang
Mueller, Frank
Quantum Physics
Information Theory
This work presents a hardware-efficient and fully parallelizable decoder for quantum LDPC codes that leverages belief propagation (BP) with a speculative post-processing strategy inspired by classical Chase decoding algorithm. By monitoring bit-level oscillation patterns during BP, our method identifies unreliable bits and generates multiple candidate vectors to selectively flip syndromes. Each modified syndrome is then decoded independently using short-depth BP, a process we refer to as BP-SF (syndrome flip). This design eliminates the need for costly Gaussian elimination used in the current BP-OSD approaches. Our implementation achieves logical error rates comparable to or better than BP-OSD while offering significantly lower latency due to its high degree of parallelism for a variety of bivariate bicycle codes. Evaluation on the [[144,12,12]] bivariate bicycle code shows that the proposed decoder reduces average latency to approximately $70\%$ of BP-OSD. When post-processing is parallelized the average latency is reduced by $55\%$ compared to the single process implementation, with the maximum latency reaching as low as $18\%$. These advantages make it particularly well-suited for real-time and resource-constrained quantum error correction systems.
title Fully Parallelized BP Decoding for Quantum LDPC Codes Can Outperform BP-OSD
topic Quantum Physics
Information Theory
url https://arxiv.org/abs/2507.00254