Abstract Unmanned aerial vehicles (UAVs) emerge as a flexible and cost‐effective solution for mobile quantum communication, showing significant potential. Despite the challenges posed by environmental noise in free‐space channels for efficient entanglement distribution, the noise‐resistant properties of high‐dimensional (HD) quantum states provide a promising solution to these issues. This work establishes a HD orbital angular momentum (OAM) entanglement distribution model on a UAV platform, systematically analyzing the effects of environmental conditions and platform parameters. Based on this model, a HD subspace coding protocol is investigated, with optimized subspace dimension and mode sets to enhance the performance. Furthermore, the use of the source modulation technique can significantly improve the key rate and transmission distance of the system. This work holds important implications for expanding UAV platform coverage, improving adaptability to environmental factors, and advancing the development of heterogeneous quantum networks.
Abstract Unmanned aerial vehicles (UAVs) emerge as a flexible and cost‐effective solution for mobile quantum communication, showing significant potential. Despite the challenges posed by environmental noise in free‐space channels for efficient entanglement distribution, the noise‐resistant properties of high‐dimensional (HD) quantum states provide a promising solution to these issues. This work establishes a HD orbital angular momentum (OAM) entanglement distribution model on a UAV platform, systematically analyzing the effects of environmental conditions and platform parameters. Based on this model, a HD subspace coding protocol is investigated, with optimized subspace dimension and mode sets to enhance the performance. Furthermore, the use of the source modulation technique can significantly improve the key rate and transmission distance of the system. This work holds important implications for expanding UAV platform coverage, improving adaptability to environmental factors, and advancing the development of heterogeneous quantum networks.
The integration of terrestrial- and satellite-based quantum key distribution (QKD) experiments has markedly advanced global-scale quantum networks, showcasing the growing maturity of quantum technologies. Notably, the use of unmanned aerial vehicles (UAVs) as relay nodes has emerged as a promising method to overcome the inherent limitations of fiber-based and low-Earth orbit (LEO) satellite connections. This paper introduces a protocol for measurement-device-independent QKD (MDI-QKD) using photon orbital angular momentum (OAM) encoding, with UAVs as relay platforms. Leveraging UAV mobility, the protocol establishes a secure and efficient link, mitigating threats from untrusted UAVs. Photon OAM encoding addresses reference frame alignment issues exacerbated by UAV jitter. A comprehensive analysis of atmospheric turbulence, state-dependent diffraction (SDD), weather visibility, and pointing errors on free-space OAM-state transmission systems was conducted. This analysis elucidates the relationship between the key generation rate and propagation distance for the proposed protocol. Results indicate that considering SDD significantly decreases the key rate, halving previous data results. Furthermore, the study identifies a maximum channel loss capacity of 26 dB for the UAV relay platform. This result is pivotal in setting realistic parameters for the deployment of UAV-based quantum communications and lays the foundation for practical implementation strategies in the field.
Abstract The integration of unconditional security of quantum key distribution (QKD) with the flexibility of unmanned aerial vehicles (UAVs) presents significant potential for the deployment of comprehensive quantum networks. However, imperfect components of practical QKD systems offer avenues for eavesdropping, while the limited payload capacity and vibrations of UAVs present substantial challenges. This paper introduces an orbital angular momentum (OAM) encoding strategy combined with decoy‐state and the measurement‐device‐independent QKD (MDI‐QKD) protocol to address security issues and reference frame misalignment in UAV‐based QKD systems. Nevertheless, the communication performance of the OAM‐MDI‐QKD system is significantly affected by complex environmental challenges in the airborne channel. To improve the degraded communication performance in airborne platforms, an enhanced grey wolf optimization‐differential evolution (GWO‐DE) algorithm is developed, utilizing chaotic mapping and a nonlinear decay factor to strengthen global search and convergence capabilities, which effectively addresses the search limitations of local search algorithms (LSA) when dealing with high‐dimensional objective functions. Simulation results demonstrate that the GWO‐DE algorithm outperforms other traditional optimization algorithms in terms of optimization precision and transmission distance enhancement, with computational speed meeting system requirements.
High-dimensional quantum key distribution (HD-QKD) provides notable advantages over qubit-based QKD, including higher key rates and greater noise resilience. Leveraging the orbital angular momentum states of structured photons to encode information has become a prominent method for implementing HD-QKD. However, practical challenges such as state-dependent diffraction, limited receiving aperture, and atmospheric turbulence impose constraints on the attainable performance and encoding dimension of QKD in free-space links. In this work, we address these challenges with focused, structured photons. Numerical simulations indicate that this method markedly enhances transmission efficiency and improves the robustness against turbulence, resulting in higher key rates and extended transmission distances in free-space HD-QKD. Additionally, focused, structured photons allow us to implement higher-dimensional QKD and enable QKD systems to achieve superior performance with smaller receiving apertures in a turbulent free-space link. This makes our approach particularly advantageous for applications of unmanned aerial vehicles and satellite platforms. Our work contributes to exploring the robust QKD schemes employing structured photons and may promote its application in quantum networks.
Abstract High-dimensional quantum key distribution (HD-QKD) is a topic of growing interest in the quantum communication community, not only for its inherent properties but also for its possible applications. As the typical freedom in HD-QKD, orbital angular momentum (OAM) has made significant advancements in experiments recently. However, in the airborne scenario, different states suffer different amounts of misalignment and turbulence. A complete theoretical analysis model for the transmission characteristics of OAM in atmospheric channels is lacking. In this paper, we systematically analyze the extent to which degeneration including channel power loss and mode crosstalk are influenced by misalignment and turbulence effects. Furthermore, the performance of OAM-encoded HD-QKD system in different dimensions is evaluated while incorporating finite-key effects. We demonstrate that the performance of OAM-encoded HD-QKD will be better at short range, which provide a reference to implement QKD based on task requirements. Since OAM is desired to increase the capacity of QKD system and experiments have already been carried out, our work can not only bridge the gap between theory and practice, but also optimize experimental parameters and improve system performance.
ABSTRACT Quantum communication represents a cutting‐edge research frontier, yet its wide‐area deployment remains constrained by infrastructure limitations. Unmanned aerial vehicle (UAV) technology, with its inherent flexibility and rapid deployability, offers a promising solution for dynamic quantum network expansion, giving rise to the emerging paradigm of UAV quantum networks. However, these networks face critical challenges, including energy and quantum resource constraints, as well as fragile quantum links. To address these issues, we propose an efficient clustering‐based communication scheme and develop an Energy‐Neighbor Weight Adaptive Clustering Algorithm (ENW‐ACA). This algorithm incorporates a multi‐index cluster head election strategy and a multi‐level routing mechanism to achieve low energy dissipation, high quantum resource utilization, and improved network throughput. Simulation results demonstrate that ENW‐ACA significantly outperforms traditional non‐clustering routing across multiple performance metrics, including energy efficiency, quantum resource utilization, and network throughput, while maintaining its advantages as the network scale expands. These findings provide theoretical support for clustering and routing design in UAV quantum networks and establish a technical foundation for their large‐scale deployment.
Unmanned aerial vehicles (UAVs) are a promising platform for flexible quantum communication, complementing fiber and satellite links. However, the performance of UAV-based entanglement distribution is limited by the dynamic atmospheric channel. Traditional statistical models, relying on static assumptions, cannot accurately represent real-time channel variations crucial for optimization. To address this, we propose an AI-driven adaptive prediction framework using the Patch Time Series Transformer (PatchTST) model to forecast UAV-to-ground quantum channel transmittance. Simulations demonstrate that our method accurately predicts dynamic transmittance fluctuations and outperforms standard recurrent neural network benchmarks in capturing relevant channel features. Additionally, it enables reliable estimation of key performance metrics like the BBM92 secure key rate. This work demonstrates an effective deep learning strategy for real-time channel prediction, enhancing adaptive optimization and robustness in UAV-based quantum entanglement distribution.