Quantum-Enhanced Security Framework for Next-Generation Space–Terrestrial Networks

Guest editorial IJSCN special issue on 3GPP NTN standards for future satellite communications

Integrated terrestrial and non-terrestrial network (TN-NTN) architectures offer a promising solution for expanding coverage and improving capacity for the network. While nonterrestrial networks (NTNs) are primarily exploited for these specific reasons, their role in alleviating terrestrial network (TN) load and enabling energy-efficient operation has received comparatively less attention. In light of growing concerns associated with the densification of terrestrial deployments, this work aims to explore the potential of NTNs in supporting a more sustainable network. In this paper, we propose a novel online optimisation framework for integrated TN-NTN architectures, built on a multi-armed bandit (MAB) formulation and leveraging the Bandit-feedback Constrained Online Mirror Descent (BCOMD) algorithm. Our approach adaptively optimises key system pa-rameters-including bandwidth allocation, user equipment (UE) association, and macro base station (MBS) shutdown-to balance network capacity and energy efficiency in real time. Extensive system-level simulations over a 24 -hour period show that our framework significantly reduces the proportion of unsatisfied UEs during peak hours and achieves up to 19 % throughput gains and 5 % energy savings in low-traffic periods, outperforming standard network settings following 3GPP recommendations.

Remarkable progress has been made in satellite-based quantum key distribution (QKD), which can effectively provide QKD service even at the intercontinental scale and construct an ultralong-distance global quantum network. But there are still some places where terrestrial fiber and ground stations cannot be constructed, like harsh mountainous areas and air space above the sea. So the airborne platform is expected to replace the ground station and provide flexible and relay links for the large-scale integrated communication network. However, the photon transmission rate would be randomly reduced, owing to the randomly distributed boundary layer that surrounds the surface of the aircraft when the flight speed is larger than 0.3 Ma. Previous research of airborne QKD with boundary layer effects is mainly under the air-to-ground scenario in which the aircraft is a transmitter, while the satellite-to-aircraft scenario is rarely reported. In this article, we propose a performance evaluation scheme of satellite-to-aircraft QKD with boundary layer effects in which the aircraft is the receiver. With common experimental settings, the boundary layer would introduce a ∼31 dB loss to the transmitted photons, decrease ∼47% of the quantum communication time, and decrease ∼51% of the secure key rate, which shows that the aero-optical effects caused by the boundary layer cannot be ignored. Our study can be performed in future airborne quantum communication designs.

An integrated Non-Terrestrial Network (NTN) and Terrestrial Network (TN) is a promising solution to satisfy the demands for ubiquitous coverage and increased capacity requirements in mobile cellular networks. In this paper, spectrum sharing mechanism and co-channel interference in TN-NTN integrated system are studied. A novel reverse spectrum pairing mechanism is proposed to mitigate the co-channel interference to the NTN service link. A comprehensive analysis of TN interference to NTN satellite receiver under various scenarios with realistic environment settings is presented. The simulation results show that due to the high directivity of base station antennas, the aggregated base station-to-NTN interference in reverse pairing is much lower than the aggregated UE-to-NTN interference in normal pairing. The proposed reverse pairing overwhelms the normal pairing by a 35 dB higher SINR in the service link. NTN UEs with high elevation angles could also enjoy communication services equivalent to cellular networks in reverse pairing. With a lower co-channel interference to the NTN satellite, the reverse spectrum pairing allows the deployment of an integrated TN-NTN with service link spectrum sharing.

As an important support for quantum communication, quantum key distribution (QKD) networks have achieved a relatively mature level of development, and they face higher requirements for multi-user end-to-end networking capabilities. Thus, QKD networks need an effective management plane to control and coordinate with the QKD resources. As a promising technology, software defined networking (SDN) can separate the control and management of QKD networks from the actual forwarding of the quantum keys. This paper systematically introduces QKD networks enabled by SDN, by elaborating on its overall architecture, related interfaces, and protocols. Then, three-use cases are provided as important paradigms with their corresponding schemes and simulation performances.

We propose a load balancing algorithm for a multi-RAT (radio access technology) network including a non-terrestrial network (NTN) and a terrestrial network (TN). Fifth generation (5G) and beyond-5G networks consider NTNs to provide connectivity and data delivery to large numbers of user equipments (UEs). However, previous load balancing algorithms do not consider the coexistence of NTNs and TNs and ignore the different resource allocation units in a multi-RAT network. Hence, we define a radio resource utilization ratio (RRUR) as a common load metric to measure the cell load of each RAT and employ an adaptive threshold to determine overloaded cells. The proposed algorithm consists of two steps to overcome the uneven load distribution across 5G cells: intra-RAT load balancing and inter-RAT load balancing. Based on the RRUR of a cell, the algorithm first performs intra-RAT load balancing by offloading the appropriate edge UEs of an overloaded cell to underutilized neighboring cells. If the RRUR of the cell is still higher than a predefined threshold, then inter-RAT load balancing is performed by offloading the delay-tolerant data flows of UEs to a satellite link. Furthermore, the algorithm estimates the impact of moving loads to the target cell load to avoid unnecessary load balancing actions. Simulation results show that the proposed algorithm not only distributes the load across terrestrial cells more evenly but also increases network throughput and the number of quality of service satisfied UEs more than previous load balancing algorithms.

Reliability and security concerns have increased demand for Virtual Private Networks (VPNs). Ideally, a VPN service should offer autonomous overlay networks with guaranteed bandwidth allocations over a shared network. Network providers seek an automated VPN creation and management process, while users of a VPN would greatly benefit from secure control over the handling of their traffic. Currently, network infrastructure does not support such partitioning services and, due to its static nature, it cannot be adapted to meet such new demands. Active and Programmable Network research has developed a number of adaptable architectures. However, its current focus is on theoretical service deployment rather than on applicability to large and shared networking environments. This paper presents the application of a new programmable architecture to enable on-demand VPN construction, bandwidth management, and secure autonomous VPN control onto shared commercial infrastructure.

The security of quantum cryptography relies on the foundations of quantum mechanics, in contrast to traditional public key cryptography which relies on the computational difficulty of certain mathematical functions, and cannot provide any indication of eavesdropping or guarantee of key security. The proposal present in this work develops a quantum key distribution model to safeguard security in large networks, in the directions of classical cryptography and quantum cryptography. Two three-party Quantum key distribution are used in this model, one with implicit user authentication and the other with explicit mutual authentication, are proposed to demonstrate the merits of the new combination. The performance of Quantum Key Distribution (QKD) systems have notably progressed since the early experimental demonstrations. The current evolutions in QKD research indicate that the pace of this progression is very likely to be maintained, if not increased, in the future years. In parallel to these improvements of QKD techniques, commercial products are also being developed, making QKD deployment a feasible alternative for securing real data networks. Deployment of a real QKD network is however far from being straightforward. It requires development of a network architecture connecting multiple users that may possibly be very far away from each other. Considering the fact that the existing QKD links are only point-to-point, and intrinsically limited in distance, deployment of a practical QKD network structure is a nontrivial problem. The proposed work describes the proposed architecture for a QKD network specify the requirements relevant to the network design, protocols, and services. The objective of this specification is to define the major components and their main features The proposal provides security against such attacks as man-in-the-middle, eavesdropping and replay. It also improves the efficiency of the quantum key distribution which contains the fewest number of communication rounds among existing Quantum key distributions. In this model two parties can share and use a long-term secret (repeatedly). To prove the security of the proposed schemes, this proposed model provides a primitive called the Unbiased-Chosen Basis (UCB) assumption with the quantum key in angular positions.

The largely used of cyberspace has brought the attention of business interposes across the globe in modern era which resulted in numerous security issues. Business enterprises find it difficult to protect and manage resource sharing and data infrastructure effectively. The business enterprises consider Virtual private network (VPN) as a novel development to protect data and information, and to create a VPN connection, it is significant to consider the type of security protocols to use to make VPN more efficient and more powerful. The significant issue in this research is to study the performance of Secure Socket Layer (SSL) in VPN with intrusion detection systems (IDS) on Linux operating system in terms of Quality of Service (QoS) parameters (throughput, latency and packet loss). We also used two different encryption algorithms, Triple Data Encryption Standard (TDES/3DES) and Advance Encryption Standard (AES). Encryption algorithms are used to encrypt data, so it cannot be read or modify by a third-party while in transit between two end points of a network. This research found that when considering throughput, packet loss and latency in network infrastructures, SSL/3DES offers fair and reasonable performance than SSL/AES. VPN protocols with higher throughput have the best performance and VPN protocol the low packet loss has the best performance. The research indicated deploying SSL/3DES is more effective in business enterprises also indicated that IDS could be able to function effectively on both protected traffic packets (VPN packets) and server log files.

This study successfully designed a network plan incorporating a Virtual Private Network (VPN) for Kasipag Microfinancing Incorporated (KMI). Employing a developmental research design approach and following the network development life cycle stages of planning, analysis, design, and simulation, the researchers evaluated the feasibility of the network design for implementation in KMI. The findings strongly recommend KMI to proceed with the implementation of the designed network plan that includes a VPN, as it offers significant benefits and advantages. Implementing a VPN in KMI's network infrastructure will greatly enhance network security and enable secure remote access to valuable resources, which is particularly crucial in today's digital landscape emphasizing remote work and data privacy. The thorough simulation of the network plan confirms its feasibility and ensures KMI will have a reliable and efficient network infrastructure. Additionally, the implementation of the network plan will provide KMI with a competitive edge by enabling seamless communication and streamlined data transfer between branches. This will enhance collaboration, improve operational efficiency, and increase overall organizational effectiveness. The cost analysis conducted by the researchers guarantees that the project remains within budget, offering KMI a clear breakdown of expenses for informed decision-making. In conclusion, the recommended implementation of the network plan incorporating a VPN will empower KMI with improved network security, secure remote access, and a competitive advantage in the microfinancing industry. By embracing these advancements, KMI can foster growth, productivity, and success in the ever-evolving digital landscape.

Quantum key distribution (QKD) can provide point-to-point information-theoretic secure key services for two connected users. In fact, the development of QKD networks needs more focus from the scientific community in order to broaden the service scale of QKD technology to deliver end-to-end secure key services. Of course, some recent efforts have been made to develop secure communication protocols based on QKD. However, due to the limited key generation capability of QKD devices, high quantum secure key utilization is the major concern for QKD networks. Since traditional routing techniques do not account for the state of quantum secure keys on links, applying them in QKD networks directly will result in underutilization of quantum secure keys. Therefore, an efficient routing protocol for QKD networks, especially for large-scale QKD networks, is desperately needed. In this study, an efficient routing protocol based on optimized link-state routing, namely QOLSR, is proposed for QKD networks. QOLSR considerably improves quantum key utilization in QKD networks through link-state awareness and path optimization. Simulation results demonstrate the validity and efficiency of the proposed QOLSR routing protocol. Most importantly, with the growth of communication traffic, the benefit becomes even more apparent.

The fifth generation (5G) of wireless communications offers a plethora of new communications paradigms, scenarios, and services. Among them, the integration of terrestrial and non-terrestrial networks is one of the most relevant aiming at providing seamless ubiquity connectivity and economies of scale for satellite communications. This chapter presents the most relevant experimental testbeds for the demonstration of 5G and beyond 5G adaptations for their use in non-terrestrial networks. In the first sections, a state-of-the-art review is presented including a description of the principal hardware and software components, highlighting OpenAirInterface as the most prominent open-source 5G stack. The latest sections describe the features and capabilities of the most advanced 5G non-terrestrial network testbeds based on OpenAirInterface: the 5G-SpaceLab and the 5G-Lab.

Large-scale quantum networks with thousands of nodes require scalable network protocols and physical hardware to realize. In this paper, we introduce packet switching as a paradigm for quantum data transmission in both future and near-term quantum networks. We propose a classical-quantum data frame structure and explore methods of frame generation and processing. Further, we present conceptual designs for a quantum reconfigurable optical add-drop multiplexer to realize the proposed transmission scheme. Packet switching allows for a universal design for a next-generation Internet where classical and quantum data share the same network protocols and infrastructure. In this quantum networking paradigm, entanglement distribution, as with quantum key distribution, is an application built on top of the quantum network rather than as a network designed especially for those purposes. For analysis of the network model, we simulate the feasibility of quantum packet switching for some preliminary models of quantum key and entanglement distribution. Finally, we discuss how our model can be integrated with other network models toward a realization of the quantum Internet.

We develop a novel key routing algorithm for quantum key distribution (QKD) networks that utilizes a distribution of keys between remote nodes, i.e., not directly connected by a QKD link, through multiple non-overlapping paths. This approach focuses on the security of a QKD network by minimizing potential vulnerabilities associated with individual trusted nodes. The algorithm ensures a balanced allocation of the workload across the QKD network links, while aiming for the target key generation rate between directly connected and remote nodes. We present the results of testing the algorithm on two QKD network models consisting of 6 and 10 nodes. The testing demonstrates the ability of the algorithm to distribute secure keys among the nodes of the network in an all-to-all manner, ensuring that the information-theoretic security of the keys between remote nodes is maintained even when one of the trusted nodes is compromised. These results highlight the potential of the algorithm to improve the performance of QKD networks.

This study quantitatively evaluates the throughput loss of a non-terrestrial network (NTN) user equipment (UE) as a function of its isolation distance from a terrestrial network (TN) cluster when the TN and NTN operate in adjacent frequency bands. A 5 % throughput loss was defined as the interference threshold, and the minimum isolation distance required to satisfy this criterion was derived based on both the average and the 5th-percentile throughput loss values. The results indicate that the minimum isolation distance is approximately 0.197 km for the average case and 1.036 km for the 5th-percentile case, corresponding to a relaxation of about 1.3 km and 0.5 km, respectively, compared with the 1.5 km isolation distance recommended by 3GPP.