Progressive Rate-Filling: A Framework for Agile Construction of Multilevel Polar-Coded Modulation

TL;DR

This paper introduces a progressive rate-filling framework for efficiently constructing multilevel polar-coded modulation schemes, enabling rapid and robust rate allocation independent of channel conditions.

Contribution

It proposes a novel, low-complexity rate-filling method that uses fixed bit rankings and target sum-rate approximation for agile multilevel polar coding.

Findings

The method achieves $O(m)$ complexity, suitable for practical systems.

It is robust across various modulation and coding schemes.

The approach simplifies rate allocation without channel-dependent computations.

Abstract

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.