1.
Trinh, Phuc V.; Sugiura, Shinya; Xu, Chao; Hanzo, Lajos
Toward Quantum SAGINs Harnessing Optical RISs: Applications, Advances, and the Road Ahead Journal Article
In: IEEE Network, vol. 39, no. 3, pp. 215–222, 2025, ISSN: 1558-156X.
Abstract | Links | BibTeX | Tags: Airplanes, Buildings, Drones, free-space optics, Low earth orbit satellites, next-generation network, Optical beams, Optical fiber networks, Optical fibers, optical reconfigurable intelligent surface, Quantum entanglement, quantum Internet, Relays, Satellites, Space-air-ground integrated network, Space-air-ground integrated networks
@article{trinh_toward_2025,
title = {Toward Quantum SAGINs Harnessing Optical RISs: Applications, Advances, and the Road Ahead},
author = {Phuc V. Trinh and Shinya Sugiura and Chao Xu and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/10858146},
doi = {10.1109/MNET.2025.3536848},
issn = {1558-156X},
year = {2025},
date = {2025-05-01},
urldate = {2025-10-08},
journal = {IEEE Network},
volume = {39},
number = {3},
pages = {215–222},
abstract = {The space-air-ground integrated network (SAGIN) concept is vital for the development of seamless next-generation (NG) wireless coverage, integrating satellites, unmanned aerial vehicles, and manned aircraft along with the terrestrial infrastructure to provide resilient ubiquitous communications. By incorporating quantum communications using optical wireless signals, SAGIN is expected to support a synergistic global quantum Internet alongside classical networks. However, long-distance optical beam propagation requires line-of-sight (LOS) connections in the face of beam broadening and LoS blockages. To overcome blockages among SAGIN nodes, we propose deploying optical reconfigurable intelligent surfaces (ORISs) on building rooftops. They can also adaptively control optical beam diameters for reducing losses. This article first introduces the applications of ORISs in SAGINs, then examines their advances in quantum communications for typical SAGIN scenarios. Finally, the road ahead towards the practical realization of ORIS-aided NG quantum SAGINs is outlined.},
keywords = {Airplanes, Buildings, Drones, free-space optics, Low earth orbit satellites, next-generation network, Optical beams, Optical fiber networks, Optical fibers, optical reconfigurable intelligent surface, Quantum entanglement, quantum Internet, Relays, Satellites, Space-air-ground integrated network, Space-air-ground integrated networks},
pubstate = {published},
tppubtype = {article}
}
The space-air-ground integrated network (SAGIN) concept is vital for the development of seamless next-generation (NG) wireless coverage, integrating satellites, unmanned aerial vehicles, and manned aircraft along with the terrestrial infrastructure to provide resilient ubiquitous communications. By incorporating quantum communications using optical wireless signals, SAGIN is expected to support a synergistic global quantum Internet alongside classical networks. However, long-distance optical beam propagation requires line-of-sight (LOS) connections in the face of beam broadening and LoS blockages. To overcome blockages among SAGIN nodes, we propose deploying optical reconfigurable intelligent surfaces (ORISs) on building rooftops. They can also adaptively control optical beam diameters for reducing losses. This article first introduces the applications of ORISs in SAGINs, then examines their advances in quantum communications for typical SAGIN scenarios. Finally, the road ahead towards the practical realization of ORIS-aided NG quantum SAGINs is outlined.
2.
Zhang, Chao; Li, Qingchao; Xu, Chao; Yang, Lie-Liang; Hanzo, Lajos
Space-Air-Ground Integrated Networks: Their Channel Model and Performance Analysis Journal Article
In: IEEE Open Journal of Vehicular Technology, vol. 6, pp. 1501–1523, 2025, ISSN: 2644-1330.
Abstract | Links | BibTeX | Tags: Absorption, Atmospheric modeling, Attenuation, Bending, Channel model, Channel models, Doppler effect, Earth, Fading channels, goodput, Meteorology, Performance analysis, Rician channels, Space-air-ground integrated networks
@article{zhang_space-air-ground_2025,
title = {Space-Air-Ground Integrated Networks: Their Channel Model and Performance Analysis},
author = {Chao Zhang and Qingchao Li and Chao Xu and Lie-Liang Yang and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/11018358},
doi = {10.1109/OJVT.2025.3575360},
issn = {2644-1330},
year = {2025},
date = {2025-01-01},
urldate = {2025-10-08},
journal = {IEEE Open Journal of Vehicular Technology},
volume = {6},
pages = {1501–1523},
abstract = {Given their extensive geographic coverage, low Earth orbit (LEO) satellites are envisioned to find their way into next-generation (6G) wireless communications. This paper explores space-air-ground integrated networks (SAGINs) leveraging LEOs to support terrestrial and non-terrestrial users. We first propose a practical satellite-ground channel model that incorporates five key aspects: 1) the small-scale fading characterized by the Shadowed-Rician distribution in terms of the Rician factor K, 2) the path loss effect of bending rays due to atmospheric refraction, 3) the molecular absorption modelled by the Beer-Lambert law, 4) the Doppler effects including the Earth's rotation, and 5) the impact of weather conditions according to the International Telecommunication Union Recommendations (ITU-R). Harnessing the proposed model, we analyze the long-term performance of the SAGIN considered. Explicitly, the closed-form expressions of both the outage probability and of the ergodic rates are derived. Additionally, the upper bounds of bit-error rates and of the Goodput are investigated. The numerical results yield the following insights: 1) The shadowing effect and the ratio between the line-of-sight and scattering components can be conveniently modelled by the factors of K and m in the proposed Shadowed-Rician small-scale fading model. 2) The atmospheric refraction has a modest effect on the path loss. 3) When calculating the transmission distance of waves, Earth's curvature and its geometric relationship with the satellites must be considered, particularly at small elevation angles. 3) High-frequency carriers suffer from substantial path loss, and 4) the Goodput metric is eminently suitable for characterizing the performance of different coding as well as modulation methods and of the estimation error of the Doppler effects.},
keywords = {Absorption, Atmospheric modeling, Attenuation, Bending, Channel model, Channel models, Doppler effect, Earth, Fading channels, goodput, Meteorology, Performance analysis, Rician channels, Space-air-ground integrated networks},
pubstate = {published},
tppubtype = {article}
}
Given their extensive geographic coverage, low Earth orbit (LEO) satellites are envisioned to find their way into next-generation (6G) wireless communications. This paper explores space-air-ground integrated networks (SAGINs) leveraging LEOs to support terrestrial and non-terrestrial users. We first propose a practical satellite-ground channel model that incorporates five key aspects: 1) the small-scale fading characterized by the Shadowed-Rician distribution in terms of the Rician factor K, 2) the path loss effect of bending rays due to atmospheric refraction, 3) the molecular absorption modelled by the Beer-Lambert law, 4) the Doppler effects including the Earth's rotation, and 5) the impact of weather conditions according to the International Telecommunication Union Recommendations (ITU-R). Harnessing the proposed model, we analyze the long-term performance of the SAGIN considered. Explicitly, the closed-form expressions of both the outage probability and of the ergodic rates are derived. Additionally, the upper bounds of bit-error rates and of the Goodput are investigated. The numerical results yield the following insights: 1) The shadowing effect and the ratio between the line-of-sight and scattering components can be conveniently modelled by the factors of K and m in the proposed Shadowed-Rician small-scale fading model. 2) The atmospheric refraction has a modest effect on the path loss. 3) When calculating the transmission distance of waves, Earth's curvature and its geometric relationship with the satellites must be considered, particularly at small elevation angles. 3) High-frequency carriers suffer from substantial path loss, and 4) the Goodput metric is eminently suitable for characterizing the performance of different coding as well as modulation methods and of the estimation error of the Doppler effects.