Polar code decoding improves error rates on noisy phase channels

Log Density Spectrum Based Decoding of Polar Codes for Channels with Strong Phase Noise

Information Theory

Summary

Some communication channels suffer from strong phase noise, which makes it hard for traditional decoders to correctly interpret received signals. The authors propose a new decoding method that works with distributions of phase noise rather than simple probabilities, capturing more detailed information. To keep computations manageable, they represent log-density functions using spectra and derive formulas for updating these spectra during decoding. Their method shows better error performance than standard decoders and Kalman-based approaches under strong phase noise conditions.

What this means in practice

Authors

Yinuo Mei, Daiming Qu

Abstract

A decoding method is proposed for polar codes under channels with strong phase noise. In contrast to traditional SC decoding, where recursions are performed on scalar soft information such as probabilities, the proposed decoding recurses over probability density functions defined on the phase-noise variable. To make the density-level recursion computationally tractable, we represent each log-density by its spectrum, and derive approximate formulas for the spectrum recursion, therefore, the proposed method is termed log-density spectrum recursion (LDSR). Numerical results are given under strong phase noise and AWGN, showing that a prominent superiority of error performance is achieved by LDSR in comparison with traditional SC and Kalman-based methods.