In this letter, we propose a progressive rate-filling method as a framework to study agile construction of multilevel polar-coded modulation. We show that the bit indices within each component polar code can follow a fixed, precomputed ranking sequence, e.g., the Polar sequence in the 5G standard, while their allocated rates (i.e., the number of information bits of each component polar code) can be fast computed by exploiting the target sum-rate approximation and proper rate-filling methods. In particular, we develop two rate-filling strategies based on the capacity and the rate considering the finite block-length effect. The proposed construction methods can be performed independently of the actual channel condition with ${O\left(m\right)}$ ($m$ denotes the modulation order) complexity and robust to diverse modulation and coding schemes in the 5G standard, which is a desired feature for practical systems.

中文翻译：

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渐进速率填充：多级极性编码调制的敏捷构建框架

在这封信中，我们提出了一种渐进式速率填充方法，作为研究多级极性编码调制的敏捷构造的框架。我们表明，每个分量极性码内的位索引可以遵循固定的，预先计算的排名序列，例如5G标准中的Polar序列，而它们的分配速率（即每个分量极性码的信息位数）可以是通过利用目标总速率近似值和适当的速率填充方法来快速计算。特别是，我们基于容量和速率（考虑了有限的块长效应），开发了两种速率填充策略。