Reference-frame-independent quantum key distribution with two-way classical communication

The data post-processing scheme based on two-way classical communication (TWCC) can improve the tolerable bit error rate and extend the maximal transmission distance when used in a quantum key distribution (QKD) system. In this study, we apply the TWCC method to improve the performance of reference-frame-independent quantum key distribution (RFI-QKD), and analyze the influence of the TWCC method on the performance of decoy-state RFI-QKD in both asymptotic and non-asymptotic cases. Our numerical simulation results show that the TWCC method is able to extend the maximal transmission distance from 175 km to 198 km and improve the tolerable bit error rate from 10.48% to 16.75%. At the same time, the performance of RFI-QKD in terms of the secret key rate and maximum transmission distance are still greatly improved when statistical fluctuations are considered. We conclude that RFI-QKD with the TWCC method is of practical interest.