A Binary BP Decoding Using Posterior Adjustment for Quantum LDPC Codes

Although belief propagation (BP) decoders are efficient and provide significant performance for classical low-density parity-check (LDPC) codes, they will suffer a degradation in performance for quantum LDPC (QLDPC) codes due to the limitations in the quantum field. In this paper, we propose a posterior adjustment of either a single qubit or multiple qubits within binary BP. The adjustment process changes the posterior likelihood ratio for one or multiple qubits according to the designed criterion. Simulations show the performance of both single and multi-qubit adjustment is able to outperform the conventional binary BP decoder and also outperform the BP decoder concatenated with the zero-order ordered-statistics decoding (BP+OSD-0). Moreover, with lower complexity, the performance when using our proposed decoder on the considered QLDPC codes can be close to high-order OSD.