{"ID":2865030,"CreatedAt":"2026-06-01T04:54:23.091178241Z","UpdatedAt":"2026-06-01T04:54:23.091178241Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2509.21872","arxiv_id":"2509.21872","title":"Hidden Markov Model Decoding for LDPC Codes","abstract":"The paper proposes an iterative Hidden Markov Model (HMM) for decoding a Low Density Parity Check (LDPC) code. It is demonstrated that a first-order HMM provides a natural framework for the decoder. The HMM is time-homogeneous with a fixed transition matrix and is based on a random walk through the encoded frame bits. Each hidden state contains a pair of two encoded bits, and parity checks are naturally incorporated into the observation model. The paper shows that by implementing a forward-backward smoothing estimator for the hidden states, decoding is efficient and requires only a small number of iterations in most cases. The results show that the LDPC decoding threshold is significantly improved compared to belief propagation (BP) on a Tanner graph. Numerical results are presented showing that LDPC codes under the proposed decoder yield a frame error rate (FER) and decoding threshold comparable to that of a Polar code where Successive Cancellation List (SCL) - Cyclic Redundancy Check (CRC) decoding is deployed. This is shown to be achieved even if the frame length is short (on the order of $512$ bits or less) and a regular LDPC code is used. 1","short_abstract":"The paper proposes an iterative Hidden Markov Model (HMM) for decoding a Low Density Parity Check (LDPC) code. It is demonstrated that a first-order HMM provides a natural framework for the decoder. The HMM is time-homogeneous with a fixed transition matrix and is based on a random walk through the encoded frame bits....","url_abs":"https://arxiv.org/abs/2509.21872","url_pdf":"https://arxiv.org/pdf/2509.21872v1","authors":"[\"Jan C Olivier\",\"Etienne Barnard\"]","published":"2025-09-26T04:55:04Z","proceeding":"eess.SP","tasks":"[\"eess.SP\"]","methods":"[]","has_code":false}