High-efficiency reconciliation for continuous-variable quantum key distribution using MGC-LDPC codes

Increasing the reconciliation efficiency and decreasing the frame error rate (FER) during the reconciliation for continuous-variable quantum key distribution (CV-QKD) can improve the secret key rate of CV-QKD. In this paper, we introduce matryoshka globally coupled low-density parity-check (MGC-LDPC) codes with high error correction performance into CV-QKD to increase the reconciliation efficiency. To decrease the FER, we propose an optimization method for MGC-LDPC codes during the reconciliation, thus improving the secret key rate of CV-QKD. Simulation experiments show that the reconciliation efficiency of CV-QKD can be improved to 98.39% by using the optimized MGC-LDPC codes, and the secure transmission distance can be extended to 190 km.