List decoding of polar codes is an outstanding decoding method, in which a fixed-size list is applied to retain the most probable paths. In general, it is preferable to use a large-size list in the decoding to achieve excellent error-control performance, but this can lead to high complexity. Moreover, the list decoding is still a one-time-pass algorithm with hard-decision outputs, which is not well suited for advanced concatenated coding systems. In this paper, a novel adjustable list decoding is proposed, in which the list size can be adjusted appropriately. Based on the reliability analyses of the decoding list, dynamic thresholds are designed to precisely guide the adjustments. The adjustable list decoding can also achieve excellent error-control performance, but the complexity is significantly reduced. Moreover, we propose an iterative adjustable list decoding scheme with soft-decision outputs for concatenated polar-coding systems, in which a log-likelihood-ratio update strategy is elaborately designed. It can achieve much better error-control performance compared with the existing iterative decoding schemes, such as the belief propagation (BP) decoding, and soft cancellation (SCAN) decoding. As the number of iterations increases, the decoding performance gradually improves, but the complexity increases little due to efficient complexity control designs.

中文翻译：

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Polar码的迭代可调软表解码

极化码的列表解码是一种优秀的解码方法，其中应用固定大小的列表来保留最可能的路径。一般来说，最好在解码中使用大尺寸的列表以实现出色的错误控制性能，但这会导致高复杂度。此外，列表解码仍然是具有硬判决输出的一次性算法，这不太适合高级级联编码系统。在本文中，提出了一种新颖的可调整列表解码，其中可以适当调整列表大小。基于解码列表的可靠性分析，设计动态阈值以精确引导调整。可调整列表解码也可以实现出色的错误控制性能，但复杂度显着降低。而且，我们为级联极坐标编码系统提出了一种具有软判决输出的迭代可调列表解码方案，其中精心设计了对数似然比更新策略。与现有的迭代解码方案（例如置信传播（BP）解码和软消除（SCAN）解码）相比，它可以实现更好的错误控制性能。随着迭代次数的增加，解码性能逐渐提高，但由于有效的复杂度控制设计，复杂度几乎没有增加。例如置信传播（BP）解码和软消除（SCAN）解码。随着迭代次数的增加，解码性能逐渐提高，但由于有效的复杂度控制设计，复杂度几乎没有增加。例如置信传播（BP）解码和软消除（SCAN）解码。随着迭代次数的增加，解码性能逐渐提高，但由于有效的复杂度控制设计，复杂度几乎没有增加。