Terahertz (THz) communication is a topic of much research in the context of high-capacity next-generation wireless networks. Quantum communication is also a topic of intensive research, most recently in the context of space-based deployments. In this work we explore the use of THz frequencies as a means to achieve quantum communication within a constellation of micro-satellites in Low-Earth-Orbit (LEO). Quantum communication between the micro-satellite constellation and high-altitude terrestrial stations is also investigated. Our work demonstrates that THz quantum entanglement distribution and THz quantum key distribution are viable deployment options in the micro-satellite context. We discuss how such deployment opens up the possibility for simpler integration of global quantum and wireless networks. The possibility of using THz frequencies for quantumradar applications in the context of LEO deployments is briefly discussed.
Terahertz (THz) communication is a topic of much research in the context of high-capacity next-generation wireless networks. Quantum communication is also a topic of intensive research, most recently in the context of space-based deployments. In this work we explore the use of THz frequencies as a means to achieve quantum communication within a constellation of micro-satellites in Low-Earth-Orbit (LEO). Quantum communication between the micro-satellite constellation and high-altitude terrestrial stations is also investigated. Our work demonstrates that THz quantum entanglement distribution and THz quantum key distribution are viable deployment options in the micro-satellite context. We discuss how such deployment opens up the possibility for simpler integration of global quantum and wireless networks. The possibility of using THz frequencies for quantumradar applications in the context of LEO deployments is briefly discussed.
With the rapid advancement of Low Earth Orbit (LEO) satellite constellations, ensuring the security of satellite-to-ground communication has become a critical concern. Traditional cryptographic techniques, while effective against classical attacks, face increasing threats from quantum computing. This paper proposes a quantum key secure transmission method tailored for LEO satellite-ground communication scenarios. The method integrates quantum key distribution (QKD) with dynamic channel estimation and orbital mobility prediction to support secure and low-latency key handshakes between satellites and ground stations. A hybrid encryption strategy is introduced, where QKD-generated keys are used to refresh symmetric session keys in real time, significantly enhancing resistance to eavesdropping and man-in-the-middle attacks. Simulation results demonstrate that the proposed method ensures stable key distribution under Doppler-shifted and intermittent link conditions, achieving improved secrecy capacity and resilience against quantum-level adversaries. This work provides a viable and scalable quantum-safe communication solution for future secure satellite networks.
This article will explore the design and implementation of quantum networks in space integrated with quantum networks on Earth. We propose a three-layer approach, involving GEO and LEO satellites integrated with terrestrial ground stations. We first analyze the channel conditions between the three layers, and then highlight the key role of LEO satellites in the integrated space-terrestrial system – namely the source of entanglement distribution between specified terrestrial stations via direct downlink quantum-optical channels. The GEO satellites in the considered system are used primarily as “coordination” stations, managing and directing the LEO satellites regarding the positioning and timing of entanglement distribution. Complexity, in the form of entanglement distillation and quantum-state correction, is concentrated at the terrestrial stations, and teleportation is used as the primary quantum channel in the LEO uplinks and the inter-terrestrial channels. Although our designs are futuristic in that they assume limited quantum memory at the transceivers, we also discuss some near-term uses of our network in which no quantum memory is available.
The use of LEO satellite systems has become widespread throughout the world, not only from the services standpoint but in large scale communication networks as well, as they make it possible to communicate from any point of the globe. Lately, the communications in the satellite field have been markedly developed thanks to the Low Earth Orbit (LEO) satellites and GEO satellite orbit. This paper deals with the main survey of these networks by a demonstration of satellite constellations constitutions and the different interfering factors, namely the number of satellites in each orbit, modelling the HANDCHECK problems or Handover satellite probably blocking. In order to preserve the information, to make sure that a seamless communication between two satellite zones is ensured the Hand check should continuously be present in satellite networks. Although the achievement of such schemes is routine work in the laboratory, nontrivial problems emerge in long-distance applications. At present, the only suitable system for long-distance quantum communication is photons. The essential work carried out in our research laboratory concerns an approach in software development of the implementation of Quantum Key Distribution (QKD) Networks with LEO orbit satellites and a reduction of the telecommunication interruption risks, which indeed will provide a better communication quality.
Research in quantum communications networks (QCNs), where multiple users desire to generate or transmit common quantum-secured information, is still in its beginning stage. To solve for the problems of both discrete variable- and continuous variable-quantum key distribution (QKD) schemes in a simultaneous manner as well as to enable the next generation of quantum communication networking, in this Special Issue paper we describe a scenario where disconnected terrestrial QCNs are coupled through low Earth orbit (LEO) satellite quantum network forming heterogeneous satellite-terrestrial QCN. The proposed heterogeneous QCN is based on the cluster state approach and can be used for numerous applications, including: (i) to teleport arbitrary quantum states between any two nodes in the QCN; (ii) to enable the next generation of cyber security systems; (iii) to enable distributed quantum computing; and (iv) to enable the next generation of quantum sensing networks. The proposed QCNs will be robust against various channel impairments over heterogeneous links. Moreover, the proposed QCNs will provide an unprecedented security level for 5G+/6G wireless networks, Internet of Things (IoT), optical networks, and autonomous vehicles, to mention a few.
The increasing demand in data rates and new emerging applications require that the future generation of satellite networks will be designed at sub-THz frequencies with ultra-broad bandwidth. Such next generation communication network owing to its own complexity will be prone to cyberattacks. In this study, we design a physical layer security for the next generation LEO satellite link. We consider a scenario where Eve is placed at a certain distance from the legitimate ground station (Bob) while communicating with low-earth orbit (LEO) satellite (Alice). By taking advantage of the uniqueness of THz atmospheric channel, we derive a closed form expression of the optimum power spectral density (PSD) of the transmitted signal so as to maximize the channel capacity. By leveraging the higher losses due to atmospheric channel and optimum PSD, we improve the physical layer security of the satellite link in the considered scenario. The simulation results show that we can enhance the normalized secrecy capacity beyond a small coverage area near the legitimate receiver Bob.
In the recent year, quantum computing and communications (QCC) represented two revolutionary technologies that are rapidly developing and integrating to interconnect heterogeneous quantum devices within the so-called Quantum Internet (QI). Despite several investigations and developments have been performed on terrestrial quantum communications over typical optical fiber links, there are some limitations in terms of extremely high losses that can be faced by deploying several repeaters, which in turns involves impractical costs for network management, especially in terms of forwarding procedures. Quantum Satellite Networks (QSNs) is capable to overcome the constraints of terrestrial optical networks, i.e., the remarkable attenuations over long distances which makes the intercontinental communications unaffordable. The recent technological developments in terms of quantum satellite communications motivated our investigation on an ad hoc quantum satellite backbone interconnecting quantum on Earth Servers in order to achieve an unprecedented computational capacity. Our aim is to investigate existing constellations, spanning from Low Earth Orbit (LEO) up to micro-satellites, to properly derive some guidelines for designing an efficient backbone. Specifically, the focus is on evaluating the impact of forwarding approaches on the end-to-end capacity (i.e., the entanglement generation rate) to achieve a trade-off between performance and cost.