Although the successive cancellation list (SCL) decoding of polar codes exhibits excellent performance, it retains many decoding paths in the list with negligible contribution to the final output, resulting in high sorting and computational complexity. In this letter, we propose a novel pruning strategy to mitigate the decoding complexity. By leveraging the blockwise soft output extraction process of soft-output SCL and soft-output fast SCL decoding, we provide an accurate approximation of the probability that a decoding path is correct, and thus accordingly prune the paths failing to meet a pre-defined reliability threshold. The complexity reduction achieved by the proposed soft-output-based pruned SCL (SOP-SCL) decoder and its fast version, SOP-FSCL decoder, is significant, without any compromise in error-correction performance. Meanwhile, they also prove to be more efficient than state-of-the-art pruned polar decoders.

翻译：虽然极化码的连续消除列表（SCL）译码展现出优异的性能，但列表中保留了大量对最终输出贡献甚微的译码路径，导致排序与计算复杂度极高。本文提出一种新颖的剪枝策略以降低译码复杂度。通过利用软输出SCL与软输出快速SCL译码的逐块软输出提取过程，我们准确近似了译码路径正确的概率，并据此剪除未达到预设可靠性阈值的路径。所提出的基于软输出的剪枝SCL（SOP-SCL）译码器及其快速版本SOP-FSCL译码器在不损失纠错性能的前提下显著降低了复杂度，同时经证明比现有最先进的剪枝极化译码器更具效率。