Action-List Reinforcement Learning Syndrome Decoding for Binary Linear Block Codes

TL;DR

This paper introduces an action-list reinforcement learning decoding scheme for linear block codes, utilizing Markov Decision Processes and deep Q-networks to improve decoding performance and reduce complexity, demonstrated on LDPC codes over BSC.

Contribution

It proposes a novel reinforcement learning-based decoding framework applicable to any code class, including state reduction techniques and leveraging code automorphisms for enhanced decoding.

Findings

Deep-Q network based decoders significantly improve performance.

State reduction via truncated MDPs enhances efficiency.

Reinforcement learning improves existing high-performance decoders.

Abstract

This paper explores the application of reinforcement learning techniques to enhance the performance of decoding of linear block codes based on flipping bits and finding optimal decisions. We describe the methodology for mapping the iterative decoding process into Markov Decision Processes (MDPs) and propose different methods to reduce the number of states in the MDP. A truncated MDP is proposed to reduce the number of states in the MDP by learning a Hamming ball with a specified radius around codewords. We then propose a general scheme for reinforcement learning based decoders applicable to any class of codes to improve the performance of decoders. We call this scheme an action-list decoding. We design an action-list decoder based on the Deep-Q network values that substantially enhance performance. We also get benefit of automorphism group of code to further improve the code performance. Additionally, we propose a feedback-based method to exploit and enhance the performance of existing high-performing decoders by applying reinforcement learning algorithms after the existing decoders. These approaches effectively reduces the complexity of the reinforcement learning block. Finally, we present experimental results for the Low-Density Parity Check (LDPC) codes over the Binary Symmetric Channel (BSC) to demonstrate the efficiency of the proposed methods.