Quantum technologies are increasingly recognized as groundbreaking advancements set to redefine the landscape of computing, communications, and sensing by leveraging quantum phenomena, like entanglement and teleportation. Quantum technologies offer an interesting set of advantages such as unconditional security, large communications capacity, unparalleled computational speed, and ultra-precise sensing capabilities. However, their global deployment faces challenges related to communication ranges and geographical boundaries. Non-terrestrial networks (NTNs) have emerged as a potential remedy for these challenges through providing free-space quantum links to circumvent the exponential losses inherent in fiber optics. Through the utilization of free-space optical (FSO) and Li-Fi links, NTNs provide an effective method for transmitting quantum states over extensive distances. This paper delves into the dynamic interplay between quantum technologies and NTNs to unveil their synergistic potential. We also investigate their integration challenges and the potential solutions to foster a symbiotic convergence of quantum and NTN functionalities while identifying avenues for enhanced interoperability. Specifically, quantum communication over NTNs imposes challenges in communication channel reliability, network flexibility, and scalability. To enhance channel reliability, multicarrier transmission techniques and spatial diversity strategies, including quantum MIMO (q-MIMO) transmission schemes, can be employed. Introducing the software defined networking (SDN) model facilitates flexible network configurations. In NTN-based quantum infrastructure, technologies like trusted relays, measurement device independent (MDI), and quantum repeaters can address scalability concerns efficiently. This paper not only offers useful insights into the mutual advantages but also presents future research directions, aiming to inspire additional studies and advance this interdisciplinary collaboration.
Quantum technologies are increasingly recognized as groundbreaking advancements set to redefine the landscape of computing, communications, and sensing by leveraging quantum phenomena, like entanglement and teleportation. Quantum technologies offer an interesting set of advantages such as unconditional security, large communications capacity, unparalleled computational speed, and ultra-precise sensing capabilities. However, their global deployment faces challenges related to communication ranges and geographical boundaries. Non-terrestrial networks (NTNs) have emerged as a potential remedy for these challenges through providing free-space quantum links to circumvent the exponential losses inherent in fiber optics. Through the utilization of free-space optical (FSO) and Li-Fi links, NTNs provide an effective method for transmitting quantum states over extensive distances. This paper delves into the dynamic interplay between quantum technologies and NTNs to unveil their synergistic potential. We also investigate their integration challenges and the potential solutions to foster a symbiotic convergence of quantum and NTN functionalities while identifying avenues for enhanced interoperability. Specifically, quantum communication over NTNs imposes challenges in communication channel reliability, network flexibility, and scalability. To enhance channel reliability, multicarrier transmission techniques and spatial diversity strategies, including quantum MIMO (q-MIMO) transmission schemes, can be employed. Introducing the software defined networking (SDN) model facilitates flexible network configurations. In NTN-based quantum infrastructure, technologies like trusted relays, measurement device independent (MDI), and quantum repeaters can address scalability concerns efficiently. This paper not only offers useful insights into the mutual advantages but also presents future research directions, aiming to inspire additional studies and advance this interdisciplinary collaboration.
Satellites and aerial platforms can be significant in the development of new telecommunications networks, allowing to deploy networks with extremely high performance even in remote areas. Recently, considering the development of quantum communication technologies, many studies are concentrated on Free Space Optic (FSO) Non-Terrestrial links, also considering that the studies performed so far on Optical Fibers (OFs) have not pointed out significant results, especially in terms of coverage. Moreover, the decrease of launch costs and the use of new satellite technologies such as CubeSats make the deployment of satellite constellations affordable. Thanks to the deployment of Non-Terrestrial Quantum Networks (NTQNs), the novel services offered by the Quantum Internet (QI) could be made easily accessible to all. In particular, Quantum Computers (QCs) can perform beyond the capabilities of any classical processor, and the interconnection of these devices on a global scale makes it possible to achieve extremely high computational capabilities, thus opening the way to new applications, such as Quantum Cloud (QCloud). Therefore, the recent studies in this area motivate this survey, which in addition to providing some base concept of quantum information, describes the current technologies needed to create quantum NT backbones. Specifically, this survey examines some studies over the period 2010–2023, which are related to the realization of quantum communications using satellites and other aerial platforms such as High Altitude Platforms (HAPS) and quantum drones. Some of the architectures that are described in this survey make use of the Software-Defined Networking (SDN) paradigm, which can be envisaged as a key enabler for the management of heterogeneous QNs in general. Furthermore, through the description of various experiments, the paper shows the applications that can be enabled by the future quantum NT backbones. In particular, in addition to improving the security of current systems through the Quantum Key Distribution (QKD), it could be possible to interconnect clusters of QCs over long distances and create extremely reliable positioning systems. Finally, the paper outlines some possible future developments.
Advancements in Non-Terrestrial Network (NTN) technology facilitate ubiquitous network access for users, whereas satellite-based Quantum Key Distribution (QKD) offers a viable solution for long-distance quantum key exchange in scenarios lacking terrestrial network infrastructure. This study explores the feasibility and practical utility of integrating NTN technology with satellite-based QKD and proposes a novel quantum-enhanced security framework for next-generation space–terrestrial networks. We have developed and deployed the first-of-its-kind 5G-enabled (fifth generation mobile communication) NTN prototype system leveraging satellite-based QKD key encryption. This system comprises a quantum satellite system, a communication satellite system, a 5G network infrastructure, and end-to-end encryption/decryption modules, aiming to validate the feasibility and usability of the proposed quantum-encrypted NTN security framework. Comprehensive tests and performance evaluations were carried out on the testbed constructed based on this prototype system, which collected critical Quality of Experience (QoE) metrics, including Round-Trip Time (RTT) and jitter, during user-plane ping measurements. Experimental results demonstrate that the integration of quantum encryption capabilities incurs an RTT overhead of 5 ms (0.75%), a necessary trade-off for systems incorporating supplementary quantum-encrypted transmission. Concurrently, the deployment of Virtual Private Network (VPN) infrastructure mitigates network jitter by 50%. These results hold critical theoretical and practical implications for the development of next-generation NTN security frameworks enabled by satellite-based QKD.
In the coming years, space missions will increasingly require communication systems capable of ensuring high-performance, safe, and reliable data transmission between ground stations and spacecraft. Since classical communication systems will be inadequate and have enormous limitations, this article intends to analyze the potential of quantum networking in addressing future challenges of space communications. We introduce well-known phenomena of quantum mechanics, such as non-cloning, entanglement, quantum measurement, and quantum teleportation, which open up a completely new scenario in the design of the communication network. Finally, we propose a network architecture for space exploration, aiming to take a look at the potential of quantum technology to establish communication between Earth and spacecraft by integrating terrestrial and non-terrestrial quantum networks.
This article envisions the concept of a ``Quantum Internet in the Sky", aiming to establish ubiquitous quantum communication links among distant nodes via free-space optical channels. Our key focus is on deploying quantum communication terminals on non-terrestrial platforms, specifically unmanned aerial vehicles and satellites, at various altitudes. By highlighting the unique characteristics of these platforms compared to terrestrial counterparts, we address inherent challenges and discuss potential solutions through meticulous system designs and analyses of typical non-terrestrial quantum communication scenarios. Finally, we illuminate the path forward by proposing essential future directions that underscore the integration of high-dimensional multipartite quantum communications with sensing, computing, and intelligence for multiple users en route to realizing a fully operational Quantum Internet.
Quantum key distribution (QKD) has emerged as a pillar of secure communication based on the inherent principles of quantum mechanics. Widespread adoption of QKD, however, is hindered by major technical limitations in both fiber-optic and free-space channels. This work explores the integration of QKD with Dense wavelength division multiplexing (DWDM), free space optics (FSO), and radio frequency (RF) networks in a bid to address these challenges. It presents a thorough review of major theories, recent experimental breakthroughs, system architectures, and advantages of hybrid terrestrial and satellite-based systems. The discussion outlines current limitations, security issues, deployment methods, and advancements in standardization initiatives. Additionally, the chapter highlights future research trends, such as RF-assisted switching, trusted node architectures, and cross-technology synchronization. These developments are envisioned to form a crucial aspect of the global networked quantum internet.
In the realm of multi-agent systems (MAS), communication delays emerge as a pivotal challenge, hindering efficient information exchange and synchronization among agents. This research proposes a novel framework leveraging quantum mechanics to address these delays and revolutionize agent interaction dynamics. The study investigates the application of quantum telecommunication and quantum computing technologies within a wireless multi-agent system (MAS) consisting of four agents. Three communication topologies star, mesh, and ring are explored. Quantum teleportation is utilized to enable state transfer between agents by encoding quantum information onto photons using properties such as polarization or phase. In quantum communication, the concept of discrete energy levels in atoms plays a crucial role in facilitating secure and efficient information exchange. These photons are transmitted through free-space optical channels, a form of wireless communication, thereby mitigating communication delays. Additionally, Quantum Key Distribution (QKD) provides unbreakable encryption, ensuring secure information exchange across the network. By integrating these technologies, this work addresses challenges such as noise, decoherence, and infrastructure limitations, demonstrating the potential of quantum telecommunication to transform wireless communication systems. While still in the early stages of development, quantum communication networks have been demonstrated using fiber optic cables and satellites, offering the potential for ultra-secure, long-distance communication. These advancements hold promise for applications in fields such as finance, healthcare, and national security. The integration of quantum telecommunication enables state transfer between agents, reducing communication delays and facilitating instantaneous information exchange by encoding quantum information onto photons using properties like polarization or phase. The findings contribute to the growing body of knowledge in quantum communication and lay the foundation for practical applications of quantum computing in complex systems. By addressing challenges related to scalability, noise resilience, and wireless implementation, this research advances the understanding of quantum technologies and their potential to enhance coordination, security, and efficiency in real-world multi-agent networks.