Fast Block Sequential Decoding of Polar Codes

TL;DR

This paper introduces a low-complexity sequential decoding algorithm for polar codes that decomposes codes into outer codes and uses fast decoding methods, improving efficiency especially with CRC and BCH codes.

Contribution

It presents a novel reduced-complexity sequential decoding algorithm for polar codes utilizing code decomposition and fast decoding techniques, with applicability to CRC and BCH codes.

Findings

Lower average decoding complexity compared to existing algorithms.

Effective decomposition of polar codes into outer codes for decoding.

Compatibility with CRC and BCH codes enhances practical utility.

Abstract

A reduced complexity sequential decoding algorithm for polar (sub)codes is described. The proposed approach relies on a decomposition of the polar (sub)code being decoded into a number of outer codes, and on-demand construction of codewords of these codes in the descending order of their probability. Construction of such codewords is implemented by fast decoding algorithms, which are available for many codes arising in the decomposition of polar codes. Further complexity reduction is achieved by taking hard decisions of the intermediate LLRs, and avoiding decoding of some outer codes. Data structures for sequential decoding of polar codes are described. The proposed algorithm can be also used for decoding of polar codes with CRC and short extended BCH\ codes. It has lower average decoding complexity compared with the existing decoding algorithms for the corresponding codes. \end{abstract}