RADAR-Q: Resource-Aware Distributed Asynchronous Routing for Entanglement Distribution in Multi-Tenant Quantum Networks

2026-03-29

AI Summary

This work addresses the inefficiency of existing quantum network routing protocols, which often waste fragile quantum states under multi-user contention for relay resources and struggle to support high-concurrency entanglement distribution. The authors propose a decentralized, resource-aware asynchronous routing protocol that, for the first time, incorporates real-time resource contention information into path selection without requiring global coordination or a central node. Built upon a DODAG topology, the protocol leverages lowest common ancestor localization, distributed asynchronous decision-making, Bell-state measurement scheduling, and quantum memory state awareness to perform entanglement swapping locally, thereby significantly shortening swap chains and reducing decoherence exposure. Experiments demonstrate that, on both grid and random topologies, the protocol achieves throughput up to 2.5× and 7.6× that of synchronous and root-centric asynchronous baselines, respectively, maintains end-to-end fidelity consistently above 0.76, attains Jain’s fairness index of 96–98%, and sustains over 50% of ideal throughput within a 1.0 ms coherence window.

Abstract

Scalable quantum networks must support concurrent entanglement requests, yet existing routing protocols fail when users compete for shared repeater resources, wasting fragile quantum states. This paper presents RADAR-Q, a resource-aware decentralized routing protocol embedding real-time resource contention into path selection. Unlike prior designs requiring global coordination or central anchors, RADAR-Q makes intelligent local decisions balancing path length and fidelity, instantaneous quantum memory availability, and intermediate Bell-State Measurement (BSM) operations. By identifying the Nearest Common Ancestor (NCA) within a DODAG hierarchy, RADAR-Q localizes entanglement swapping close to communicating users - avoiding unnecessary central detours and reducing BSM chain length and decoherence exposure. We evaluate RADAR-Q on grid and random topologies against synchronous and root-centric asynchronous baselines. Results show RADAR-Q achieves aggregate throughputs 2.5x and 7.6x higher than synchronized and root-centric designs, respectively. While baselines suffer catastrophic fidelity collapse below the 0.5 threshold under high load, RADAR-Q consistently maintains end-to-end fidelity above 0.76, ensuring pairs remain usable. Furthermore, RADAR-Q exhibits near-perfect fairness (Jain's Fairness Index 96-98%) and retains over 50% of its ideal throughput under stringent 1.0 ms coherence times. These findings establish contention-aware decentralized routing as a scalable foundation for multi-tenant quantum networks.

Problem

• entanglement distribution
• resource contention
• quantum networks
• multi-tenant
• routing

Innovation

• resource-aware routing
• decentralized quantum networking
• entanglement distribution
• Nearest Common Ancestor (NCA)
• Bell-State Measurement (BSM)