Noma-cvqkd System Achieves 23% Higher Secret Key Rate with 0.1 Precision under Quantum Attacks

The demand for secure communication networks grows alongside advances in quantum technology, yet scaling quantum key distribution (QKD) to support multiple users presents a significant challenge. Zhichao Dong, Xiaolin Zhou, and Huang Peng, alongside their colleagues, address this problem by investigating a new approach to QKD that leverages non-orthogonal multiple access. Their work introduces a system capable of dramatically increasing the rate at which secure keys can be distributed, achieving up to 23% improvement over existing quantum-orthogonal methods. By combining this innovative access technique with continuous-variable QKD and a carefully designed power allocation algorithm, the team demonstrates a system that supports a substantial number of users, even under challenging conditions such as atmospheric turbulence and long transmission distances, paving the way for practical, large-scale quantum networks. Real-World Quantum Key Distribution Challenges This research explores the integration of Quantum Key Distribution (QKD) with existing classical communication systems, particularly in challenging environments like free-space optical links, underwater channels, and urban settings. Scientists are developing hybrid quantum-classical communication methods, including techniques to transmit quantum and classical signals simultaneously, to combine the security of QKD with the higher data rates of classical systems. The work also investigates network architectures to support QKD and classical communication, considering multi-user scenarios and compatibility with existing infrastructure. The study analyzes various QKD protocols, with a strong focus on Continuous Variable QKD, examining how channel models, such as free-space, underwater, and fiber optic links, impact performance. Researchers investigate the effects of different noise sources and calculate key rates while rigorously assessing security. It also explores the feasibility of QKD in underwater environments, accounting for the absorption and scattering of light. A central theme is the development of techniques for combining quantum and classical signals, such as co-propagation, wavelength division multiplexing, and time division multiplexing. Scientists apply optimization algorithms to improve QKD system performance and resource allocation, and conduct rigorous security analyses to protect against various attacks. Simulation results demonstrate the performance of these techniques, outlining directions for future work, including practical implementation challenges and integration with existing networks. This work represents a significant contribution to the field of Quantum Key Distribution and hybrid quantum-classical communication, providing a comprehensive analysis of challenges and opportunities and proposing novel solutions for secure and high-performance communication networks. Multi-User Quantum Key Distribution with SIC Receiver Scientists have developed a new framework for multi-user quantum key distribution (QKD) designed to maximize secure key exchange rates even under malicious quantum attacks. This system utilizes Gaussian-modulated coherent states and a quantum successive interference cancellation receiver, enabling secure communication between multiple users and a base station. This innovative receiver architecture is specifically designed for multi-user CVQKD systems, allowing the base station to sequentially detect received coherent states and mitigate interference. Researchers derived precise mathematical bounds on the achievable key rates for legitimate users and the amount of information potentially intercepted by eavesdroppers, using the entropy power inequality, the maximum entropy principle, and Holevo information.

The team then developed a successive convex approximation based power allocation algorithm to maximize the overall key exchange rate, guaranteeing convergence to an optimal solution. Extensive simulations confirm the effectiveness of this approach, demonstrating that the proposed system achieves up to 23% higher key exchange rate compared to quantum-orthogonal multiple access. The system supports up to 16 users even with excess noise and maintains robust performance under varying turbulence intensities and transmission distances.

This research establishes a significant advancement in quantum communication, offering a pathway towards scalable and secure quantum networks capable of supporting multiple users in challenging environments.

Enhanced Quantum Key Distribution with NOMA-CVQKD Scientists have achieved a breakthrough in quantum key distribution, developing a new non-orthogonal multiple access based continuous-variable (NOMA-CVQKD) system designed to maximize secure key exchange rates under malicious quantum attacks. This system employs Gaussian-modulated coherent states and a heterodyne receiver, enabling secure key exchange even with an eavesdropper attempting to intercept the information. Researchers derived precise mathematical bounds on the achievable key rates for legitimate users and the amount of information potentially intercepted by eavesdroppers, utilizing the entropy power inequality and maximum entropy principle.

The team then developed a successive convex approximation based power allocation algorithm to maximize the overall key exchange rate, guaranteeing convergence to an optimal solution. Simulation results demonstrate that the proposed NOMA-CVQKD system, when combined with the power allocation algorithm, achieves up to 23% higher key exchange rate compared to quantum-orthogonal multiple access schemes. Experiments reveal the system successfully supports 16 users at a specific noise level, demonstrating its scalability and robustness. Furthermore, the system remains robust under varying turbulence intensities and transmission distances, highlighting its practical applicability in real-world communication scenarios. This advancement represents a significant step towards building a secure and scalable quantum internet, paving the way for future quantum communication networks.

Improved Key Rates Via Interference Cancellation This research presents a new framework for multi-user quantum key distribution (QKD) employing a non-orthogonal multiple access scheme, designed to operate securely despite challenges such as atmospheric turbulence and noise. By utilizing Gaussian-modulated coherent states and a successive interference cancellation receiver, the team derived precise mathematical bounds on the rate at which secure keys can be generated by legitimate users, and the amount of information potentially intercepted by eavesdroppers. A novel power allocation algorithm was developed to maximize the overall key generation rate, demonstrably converging to an optimal solution. Simulations confirm that this new approach achieves a significant improvement, up to 23%, in the key generation rate compared to conventional quantum orthogonal multiple access methods. The system also supports a greater number of users and maintains robust performance under varying channel conditions. The authors acknowledge that this work currently relies on theoretical analysis, and future research will focus on incorporating real-world effects and exploring adaptive modulation schemes. Furthermore, they plan to validate the system through experimental demonstrations using both quantum channel emulation and a laboratory prototype, ultimately aiming to enhance the practicality of this technology for large-scale quantum networks. 👉 More information 🗞 Non-Orthogonal Multiple Access-Based Continuous-Variable Quantum Key Distribution: Secret Key Rate Analysis and Power Allocation 🧠 ArXiv: https://arxiv.org/abs/2512.06748 Tags: