Fidelity- and Coherence-Aware Entanglement Routing for Regional Quantum Internet Networks

The quantum internet enables secure communication, distributed quantum computing, and remote sensing by distributing entanglement among distant nodes [1], [2]. However, establishing end-to-end entanglement across regional networks remains challenging because quantum links experience photon loss, entanglement generation is probabilistic, quantum memories have limited coherence times, and repeater resources are constrained [2], [3]. Conventional shortest-path routing does not jointly account for these quantum-specific limitations. This paper proposes a Fidelity- and Coherence-Aware Dynamic Entanglement Routing (FCADR) framework for regional quantum internet networks. The network is modelled as a graph containing end nodes, quantum repeaters, quantum memories, and lossy entanglement links. FCADR selects routes by jointly considering estimated end-to-end fidelity, entanglement-generation and swapping success probabilities, available quantum-memory capacity, and expected distribution delay. A discrete-event simulation framework is designed to compare FCADR with shortest-path routing, link-success-based routing, and fidelity-aware routing under varying channel loss, coherence time, traffic load, and node or link failures. Performance is evaluated using end-to-end fidelity, request-success rate, distribution delay, memory utilization, and network resilience. The framework aims to improve routing decisions by incorporating quantum-state quality and resource availability into dynamic path selection.