Protograph-Based Design for QC Polar Codes

TL;DR

This paper introduces a novel protograph-based design for QC polar codes that enhances decoding performance and complexity, enabling highly parallelized implementation and outperforming traditional polar codes with advanced decoding methods.

Contribution

The paper presents a new protograph-based QC polar code design that improves girth, decoding performance, and parallelization, addressing limitations of belief propagation decoding.

Findings

QC polar codes with high lifting factors outperform traditional polar codes.

The proposed design increases girth, reducing short cycles in the code graph.

Greedy pruning improves the performance-complexity trade-off.

Abstract

We propose a new family of polar coding which realizes high coding gain, low complexity, and high throughput by introducing a protograph-based design. The proposed technique called as quasi-cyclic (QC) polar codes can be highly parallelized without sacrificing decoding complexity. We analyze short cycles in the protograph polar codes and develop a design method to increase the girth. Our approach can resolve the long-standing unsolved problem that belief propagation (BP) decoding does not work well for polar codes due to the inherently short cycles. We demonstrate that a high lifting factor of QC polar codes can improve the performance and that QC polar codes with BP decoding can outperform conventional polar codes with state-of-the-art list decoding. Moreover, we show that a greedy pruning method can improve the performance-complexity trade-off.