XJ-BP: Express Journey Belief Propagation Decoding for Polar Codes

TL;DR

This paper introduces XJ-BP, a belief propagation decoding algorithm for polar codes that significantly improves efficiency and reduces complexity through a novel message passing schedule and constituent code utilization.

Contribution

The paper proposes a new XJ-BP decoding algorithm that enhances belief propagation for polar codes with a novel scheduling method and reduced computational complexity.

Findings

Simplifies min-sum BP decoder by 40.6%.

Reduces computational complexity of MS BP decoding by 90.4%.

Enables energy-efficient hardware implementation.

Abstract

This paper presents a novel propagation (BP) based decoding algorithm for polar codes. The proposed algorithm facilitates belief propagation by utilizing the specific constituent codes that exist in the factor graph, which results in an express journey (XJ) for belief information to propagate in each decoding iteration. In addition, this XJ-BP decoder employs a novel round-trip message passing scheduling method for the increased efficiency. The proposed method simplifies min-sum (MS) BP decoder by 40.6%. Along with the round-trip scheduling, the XJ-BP algorithm reduces the computational complexity of MS BP decoding by 90.4%; this enables an energy-efficient hardware implementation of BP decoding in practice.