Improved decoding method lowers errors for polar codes with CRC
PMR-Aided Shifted-Pruning SCL-Flip Decoding for CRC-Aided Polar Codes
Information Theory
Summary
Polar codes are a way to send data that helps correct errors during transmission, often used with a technique called CRC for checking accuracy. The authors introduce a new decoding method that tries more promising options from earlier attempts to fix errors without needing much extra effort. This method showed fewer mistakes in simulations compared to similar existing approaches, especially in moderate to high-quality signal conditions. Although it can sometimes require more processing steps in the worst cases, overall it offers better error correction for certain code lengths and profiles.
What this means in practice
- •For wireless communication engineers: Enhance decoding performance in wireless channels by reducing error rates using the PMR-aided shifted-pruning decoding method for CRC-polar codes.
- •For satellite communication system designers: Implement improved polar code decoding techniques to increase data integrity over noisy satellite links with moderate additional computational effort.
Authors
Niloufar Hosseinzadeh, Mohammad Morsali, Mohsen Moradi, Hessam Mahdavifar
Abstract
We propose a posterior-mass rescue (PMR)-aided shifted-pruning SCL-flip decoder for CRC-aided polar codes. After CRC-aided SCL (CA-SCL) and differential-metric shifted-pruning recovery fail to find a CRC-valid candidate, PMR locally continues discarded prefixes stored during the initial CA-SCL pass, ranked by estimated posterior mass, without increasing the shifted-pruning retry budget. Simulation results for a (128, 64) code with the Reed-Muller (RM) rate profile and a (256, 128) code with the polarization-weight (PW) rate profile, both using an 11-bit CRC, show lower observed FER than SCLF-Diff (T = 15) and the considered literature baselines under the evaluated recovery budgets, with observed FER close to that of SCLF-Diff (T = 20). At the reported moderate and high SNRs, the average reconstruction-aware path-step count is within a few percent of that of SCLF-Diff (T = 20), while at 2.0 dB it is 9.4% and 4.3% higher for the two codes, respectively. The proposed decoder also has a larger worst-case path-step bound.