Towards City-Scale Quantum Timing: Wireless Synchronization via Quantum Hubs

TL;DR

This paper introduces a city-scale wireless quantum synchronization system using entangled photons and passive CCR arrays, enabling secure, sub-nanosecond timing without active circuitry.

Contribution

It develops a comprehensive analytical model for quantum synchronization incorporating physical-layer effects and proposes a low-power, infrastructure-free solution for smart city timing.

Findings

Analytical model accurately predicts synchronization errors.

Trade-offs identified among beam waist, CCR size, and background light.

Simulation confirms system feasibility and robustness.

Abstract

This paper presents a novel wireless quantum synchronization framework tailored for city-scale deployment using entangled photon pairs and passive corner cube retroreflector (CCR) arrays. A centralized quantum hub emits entangled photons, directing one toward a target device and the other toward a local reference unit. The target, equipped with a planar CCR array, reflects the incoming photon without active circuitry, enabling secure round-trip quantum measurements for sub-nanosecond synchronization and localization. We develop a comprehensive analytical model that captures key physical-layer phenomena, including Gaussian beam spread, spatial misalignment, atmospheric turbulence, and probabilistic photon generation. A closed-form expression is derived for the single-photon detection probability under Gamma-Gamma fading, and its distribution is used to model photon arrival events and synchronization error. Moreover, we analyze the impact of background photons, SPAD detector jitter, and quantum generation randomness on synchronization accuracy and outage probability. Simulation results confirm the accuracy of the analytical models and reveal key trade-offs among beam waist, CCR array size, and background light. The proposed architecture offers a low-power, infrastructure-free solution for secure timing in next-generation smart cities.