1.
Trinh, Phuc V.; Sugiura, Shinya; Xu, Chao; Hanzo, Lajos
Optical RISs Improve the Secret Key Rate of Free-Space QKD in HAP-to-UAV Scenarios Journal Article
In: IEEE Journal on Selected Areas in Communications, vol. 43, no. 8, pp. 2747–2764, 2025, ISSN: 1558-0008.
Abstract | Links | BibTeX | Tags: Atmospheric modeling, Drones, Fluctuations, Free-space optics (FSO), Global Positioning System, high-altitude platforms (HAPs), Laser beams, low-altitude platforms (LAPs), Optical beams, Optical reflection, Power distribution, quantum key distribution (QKD), reconfigurable intelligent surface (RIS), Reconfigurable Intelligent Surfaces, Satellites
@article{trinh_optical_2025,
title = {Optical RISs Improve the Secret Key Rate of Free-Space QKD in HAP-to-UAV Scenarios},
author = {Phuc V. Trinh and Shinya Sugiura and Chao Xu and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/10993364},
doi = {10.1109/JSAC.2025.3568050},
issn = {1558-0008},
year = {2025},
date = {2025-08-01},
urldate = {2025-10-08},
journal = {IEEE Journal on Selected Areas in Communications},
volume = {43},
number = {8},
pages = {2747–2764},
abstract = {Large optical reconfigurable intelligent surfaces (ORISs) are proposed for employment on building rooftops to facilitate free-space quantum key distribution (QKD) between high-altitude platforms (HAPs) and low-altitude platforms (LAPs). Due to practical constraints, the communication terminals can only be positioned beneath the LAPs, preventing direct upward links to HAPs. By deploying ORISs on rooftops to reflect the beam arriving from HAPs towards LAPs from below, reliable HAP-to-LAP links can be established. To accurately characterize the optical beam propagation, we develop an analytical channel model based on extended Huygens-Fresnel principles for representing both the atmospheric turbulence effects and the hovering fluctuations of LAPs. This model facilitates adaptive ORIS beam-width control through linear, quadratic, and focusing phase shifts, which are capable of effectively mitigating the detrimental effects of beam broadening and pointing errors (PE). Consequently, the information-theoretic bound of the secret key rate and the security performance of a decoy-state QKD protocol are analyzed. Our findings demonstrate that quadratic phase shifts enhance the SKR at high HAP-ORIS zenith angles or mild PE conditions by narrowing the beam to optimal sizes. By contrast, linear phase shifts are advantageous at low HAP-ORIS zenith angles or moderate-to-high PE by diverging the beam to mitigate LAP fluctuations.},
keywords = {Atmospheric modeling, Drones, Fluctuations, Free-space optics (FSO), Global Positioning System, high-altitude platforms (HAPs), Laser beams, low-altitude platforms (LAPs), Optical beams, Optical reflection, Power distribution, quantum key distribution (QKD), reconfigurable intelligent surface (RIS), Reconfigurable Intelligent Surfaces, Satellites},
pubstate = {published},
tppubtype = {article}
}
Large optical reconfigurable intelligent surfaces (ORISs) are proposed for employment on building rooftops to facilitate free-space quantum key distribution (QKD) between high-altitude platforms (HAPs) and low-altitude platforms (LAPs). Due to practical constraints, the communication terminals can only be positioned beneath the LAPs, preventing direct upward links to HAPs. By deploying ORISs on rooftops to reflect the beam arriving from HAPs towards LAPs from below, reliable HAP-to-LAP links can be established. To accurately characterize the optical beam propagation, we develop an analytical channel model based on extended Huygens-Fresnel principles for representing both the atmospheric turbulence effects and the hovering fluctuations of LAPs. This model facilitates adaptive ORIS beam-width control through linear, quadratic, and focusing phase shifts, which are capable of effectively mitigating the detrimental effects of beam broadening and pointing errors (PE). Consequently, the information-theoretic bound of the secret key rate and the security performance of a decoy-state QKD protocol are analyzed. Our findings demonstrate that quadratic phase shifts enhance the SKR at high HAP-ORIS zenith angles or mild PE conditions by narrowing the beam to optimal sizes. By contrast, linear phase shifts are advantageous at low HAP-ORIS zenith angles or moderate-to-high PE by diverging the beam to mitigate LAP fluctuations.
2.
Hanzo, Lajos; Babar, Zunaira; Cai, Zhenyu; Chandra, Daryus; Djordjevic, Ivan B.; Koczor, Balint; Ng, Soon Xin; Razavi, Mohsen; Simeone, Osvaldo
Quantum Information Processing, Sensing, and Communications: Their Myths, Realities, and Futures Journal Article
In: Proceedings of the IEEE, pp. 1–51, 2025, ISSN: 1558-2256.
Abstract | Links | BibTeX | Tags: Codes, Encoding, Error correction codes, Europe, Information processing, Next generation networking, Prevention and mitigation, Quantum communications, Quantum computing, quantum error correction coding, quantum error mitigation, quantum key distribution (QKD), Quantum Machine Learning, quantum sensing, quantum-secured direct communications (QSDC), Qubit, Wireless communication
@article{hanzo_quantum_2025,
title = {Quantum Information Processing, Sensing, and Communications: Their Myths, Realities, and Futures},
author = {Lajos Hanzo and Zunaira Babar and Zhenyu Cai and Daryus Chandra and Ivan B. Djordjevic and Balint Koczor and Soon Xin Ng and Mohsen Razavi and Osvaldo Simeone},
url = {https://ieeexplore.ieee.org/document/10828532},
doi = {10.1109/JPROC.2024.3510394},
issn = {1558-2256},
year = {2025},
date = {2025-01-01},
urldate = {2025-10-08},
journal = {Proceedings of the IEEE},
pages = {1–51},
abstract = {The recent advances in quantum information processing, sensing, and communications are surveyed with the objective of identifying the associated knowledge gaps and formulating a roadmap for their future evolution. Since the operation of quantum systems is prone to the deleterious effects of decoherence, which manifests itself in terms of bit-flips, phase-flips, or both, the pivotal subject of quantum error mitigation is reviewed both in the presence and absence of quantum coding. The state of the art, knowledge gaps, and future evolution of quantum machine learning (QML) are also discussed, followed by a discourse on quantum radar systems and briefly hypothesizing about the feasibility of integrated sensing and communications (ISAC) in the quantum domain (QD). Finally, we conclude with a set of promising future research ideas in the field of ultimately secure quantum communications with the objective of harnessing ideas from the classical communications field.},
keywords = {Codes, Encoding, Error correction codes, Europe, Information processing, Next generation networking, Prevention and mitigation, Quantum communications, Quantum computing, quantum error correction coding, quantum error mitigation, quantum key distribution (QKD), Quantum Machine Learning, quantum sensing, quantum-secured direct communications (QSDC), Qubit, Wireless communication},
pubstate = {published},
tppubtype = {article}
}
The recent advances in quantum information processing, sensing, and communications are surveyed with the objective of identifying the associated knowledge gaps and formulating a roadmap for their future evolution. Since the operation of quantum systems is prone to the deleterious effects of decoherence, which manifests itself in terms of bit-flips, phase-flips, or both, the pivotal subject of quantum error mitigation is reviewed both in the presence and absence of quantum coding. The state of the art, knowledge gaps, and future evolution of quantum machine learning (QML) are also discussed, followed by a discourse on quantum radar systems and briefly hypothesizing about the feasibility of integrated sensing and communications (ISAC) in the quantum domain (QD). Finally, we conclude with a set of promising future research ideas in the field of ultimately secure quantum communications with the objective of harnessing ideas from the classical communications field.