Since the inherent serial nature of successive cancellation list (SCL) decoding results in a long latency, belief propagation (BP) decoding for polar codes has drawn attention for high-throughput applications. However, its error correction performance is inferior to that of SCL decoding. Therefore, the bit-flipping strategy has been recently applied to BP decoding, which can approach the SCL decoding performance through multiple additional decoding attempts. The original BP flip (BPF) decoding suffers from an inaccurate identification of erroneous bits by a fixed flip set (FS), which has been improved by the generalized BPF (GBPF) decoding. In this article, the GBPF decoding is extended to support multiple bits being flipped in one decoding attempt. In addition, for two types of decoding errors: detected errors and undetected errors, we propose two novel methods to more effectively identify erroneous bits. For detected errors, the concept of loop sets is defined and a loop-based identification method is introduced based on the study of error patterns of BP decoding. On the other hand, a method to generate a more accurate fixed FS is proposed for undetected errors, which considers the bit error distribution under BP decoding. Combining the two methods, the GBPF with merged sets (GBPF-MS) decoding can achieve the SCL-8 performance and outperforms the state-of-the-art BPF, BP list, and SC flip (SCF) decoding, for polar codes with length 1024 and information rate 1/2. Implemented by 40nm CMOS technology, the proposed GBPF-MS decoder with ten flips exhibits an average throughput of 4.19 Gbps at 2.5 dB, which is $1.6\times $ and $1.72\times $ faster than the state-of-the-art SCL-4 and SCF decoders, respectively.

中文翻译：

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具有比特翻转算法的改进置信传播极性解码器

由于连续对消列表 (SCL) 解码的固有串行特性导致长延迟，因此极性码的置信传播 (BP) 解码已引起高吞吐量应用的关注。但是，其纠错性能不如SCL解码。因此，比特翻转策略最近被应用于 BP 解码，它可以通过多次额外的解码尝试来接近 SCL 解码性能。原始的 BP 翻转 (BPF) 解码受到固定翻转集 (FS) 对错误位的不准确识别的影响，这已通过广义 BPF (GBPF) 解码得到改进。在本文中，GBPF 解码被扩展为支持在一次解码尝试中翻转多个位。此外，对于两种类型的解码错误：检测到的错误和未检测到的错误，我们提出了两种新方法来更有效地识别错误位。对于检测到的错误，定义了循环集的概念，并在研究BP解码错误模式的基础上引入了一种基于循环的识别方法。另一方面，针对未检测到的错误提出了一种生成更准确的固定FS的方法，该方法考虑了BP解码下的误码分布。结合这两种方法，GBPF 与合并集 (GBPF-MS) 解码可以实现 SCL-8 性能并优于最先进的 BPF、BP 列表和 SC 翻转 (SCF) 解码，对于具有长度为 1024，信息速率为 1/2。通过 40nm CMOS 技术实现，建议的具有 10 个翻转的 GBPF-MS 解码器在 2.5 dB 下表现出 4.19 Gbps 的平均吞吐量，即 1.6 美元和 1 美元。