Multidimensional Reconciliation for Continuous-Variable Quantum Key Distribution Based on Two-Edge Type Low-Density Parity-Check Codes

In the multidimensional reconciliation process of continuous-variable quantum key distribution (CVQKD), the error correction performance of the low-density parity-check code (1,DPC) directly affects the reconciliation efficiency and transmission distance. Herein, a two-edge type low-density parity-check code ( TET-I,DPC) is constructed. We introduce a cumulative structure similar to that of a repeat-accumulate code into the TET-I,DPC to improve its error correction performance. These codes obtain a smaller convergence signal-to-noise ratio, whereas the reconciliation system achieves higher coordination efficiency and longer transmission distance. The simulation results indicate that at a TET-I,DPC code rate of 0. 5 and a block length of 2 X 10(3), the convergence signal-to-noise ratio of the system is reduced to 1.02 dB, the data reconciliation efficiency is 98. 58 'A, the security key rate reaches 17.61 kb/s, and the CVQKD transmission distance increases to 11.9 km.