Dynamic Routing and Post-Processing Strategies for Hybrid Quantum Key Distribution Networks

In this paper, we consider hybrid quantum key distribution (QKD) networks with primarily quantum repeaters and a small number of trusted nodes. While the trusted nodes need to be trusted, the use of such nodes, together with efficient routing algorithms, can significantly improve the key generation rate. We show that when trusted nodes are placed at asymmetric locations relative to Alice and Bob, however, existing routing algorithms can lead to low key rate. To address this issue, we develop dynamic routing strategies that adjust routing decisions based on the current key pool conditions in the network. In addition, we investigate new and existing classical post-processing techniques that complement the dynamic routing strategies. Using extensive simulations, we show that our dynamic routing strategies can significantly outperform static strategies, and the post-processing techniques are beneficial in high noise scenarios. In addition, combining the dynamic routing strategies and post-processing techniques can further improve the overall key rate.