Rate compatible reconciliation for continuous-variable quantum key distribution using Raptor-like LDPC codes

In the practical continuous-variable quantum key distribution (CV-QKD) system, postprocessing process, particularly error correction part, significantly impacts system performance. Multi-edge type low-density parity-check (MET-LDPC) codes are suitable for CV-QKD systems because of their Shannon-limit-approaching performance at a low signal-to-noise ratio (SNR). However, process designing low-rate MET-LDPC code with good is extremely complicated. Thus, we introduce Raptor-like LDPC (RL-LDPC) into exhibiting both rate compatible property Raptor and capacity-approaching codes. Moreover, this technique can reduce cost constructing new matrix. We design RL-LDPC matrix 0.02 easily effectively adjust from 0.016 to 0.034. Simulation results show that achieve more than 98% reconciliation efficiency in range variation using only one support high-speed decoding an SNR less -16.45 dB. This allows maintain high extraction under various SNRs, paving way applications different transmission distances.