Low-Complexity Ordered Reliability Direct Error Pattern Testing (ORDEPT) Decoding with Likelihood Thresholding

TL;DR

This paper introduces a low-complexity decoding method for block codes that uses likelihood thresholding to reduce latency and computational effort while maintaining error rate performance.

Contribution

It presents an early termination criterion for ORDEPT decoding, significantly decreasing complexity and latency compared to existing algorithms without sacrificing accuracy.

Findings

Reduced decoding latency and complexity by multiple times.

Maintained block error rate performance comparable to state-of-the-art methods.

Outperformed competitors like Chase II, ORBGRAND, and GCD in efficiency.

Abstract

We propose a reduced complexity approach to pattern-based soft decoding of block codes. We start from the ORDEPT decoding algorithm which tests a list of partial error patterns organized in the order of their likelihood and attempts to complete the patterns creating candidate codewords. We then propose an early termination criterion. Once a candidate codeword is found, its log-likelihood difference to the received sequence is compared to a preset threshold and the decoding decision is instantly made in case the likelihood deviation is below the threshold. We demonstrate that while keeping the same block error rate (BLER) performance, the proposed algorithm's latency and complexity is multiple times smaller than that of the state-of-the art competitors including the Chase II, ORBGRAND, GCD, and the very recent ORDEPT with Soft-Output GRAND termination which necessitates several multiplications in each query processing.