The growing role of secure communication in defense networks has increased the need for systems that remain dependable even under advanced cyber-threat conditions. In this work, we study a Quantum Key Distribution (QKD)-enabled Optical Wireless Communication (OWC) link for short-range building-to-building applications. The system is evaluated using a MATLAB-based simulation framework that models a terrestrial free-space optical channel affected by attenuation, beam divergence, pointing misalignment, turbulence-related penalties, and additive noise. Accordingly, the performance of channel impairments is investigated with respect to QBER and the achievable secret key rate using the BB84 protocol. At the same time, a regression model based on ANN is developed to estimate the secret key rate from the measurable channel parameters. Finally, the derived key is used in the example of QOTP encryption to illustrate the secure end-to-end communication. It is concluded from the results that attenuation of channels has the most profound effect on the performance of QKD, particularly under high-loss situations where the key rate significantly decreases. In summary, the results provide a practical baseline for understanding QKD behavior over terrestrial FSO links and point to the need for future experimental verification.
The growing role of secure communication in defense networks has increased the need for systems that remain dependable even under advanced cyber-threat conditions. In this work, we study a Quantum Key Distribution (QKD)-enabled Optical Wireless Communication (OWC) link for short-range building-to-building applications. The system is evaluated using a MATLAB-based simulation framework that models a terrestrial free-space optical channel affected by attenuation, beam divergence, pointing misalignment, turbulence-related penalties, and additive noise. Accordingly, the performance of channel impairments is investigated with respect to QBER and the achievable secret key rate using the BB84 protocol. At the same time, a regression model based on ANN is developed to estimate the secret key rate from the measurable channel parameters. Finally, the derived key is used in the example of QOTP encryption to illustrate the secure end-to-end communication. It is concluded from the results that attenuation of channels has the most profound effect on the performance of QKD, particularly under high-loss situations where the key rate significantly decreases. In summary, the results provide a practical baseline for understanding QKD behavior over terrestrial FSO links and point to the need for future experimental verification.
Satellite-based free-space optical links can act as time-varying optical wireless interconnects that distribute quantum resources across space-terrestrial infrastructures, complementing the 6G vision of integrated non-terrestrial networks. Among quantum communication services, Quantum Key Distribution (QKD) is the most mature and is therefore adopted as an illustrative use case. This paper develops an attenuation-centric framework for satellite QKD based on weak-coherentpulse BB84. The considered system model links orbital geometry and optical terminal parameters to an equivalent channel transmissivity, which governs detection statistics, quantum bit error rate (QBER), and secret key generation through secrecy bounds. We derive the secret-fraction cutoff behavior with respect to channel attenuation and show how it induces time-dependent secret key rates during satellite overpasses. Numerical results using orbital data and representative parameters from the 'Micius' mission show that the minimum slant range over the onemonth observation window spans approximately 400-2400 km; approximately 34% of passes have minimum slant ranges below 900 km, and favorable passes yield secret key rates on the order of a few kbps. The proposed modeling approach provides a link-level building block for future network-level studies, where scheduling and routing of quantum-secured services can be informed by predicted key generation windows over satellite optical interconnects.
Due to the recent rapid growth of computing technologies, today's encrypted information based on classical computational complexities will soon no longer remain secure. Quantum cryptography, or quantum key distribution (QKD), relying on the physical laws of quantum mechanics, stands out as a more powerful cryptographic solution that enables the secret key to be shared securely over publicly unsecured communication channels in the presence of eavesdroppers. QKD can be possibly implemented over both optical fiber and free-space optical (FSO) links. Compared to optical fiber, FSO has the immediate advantage of flexibility and cost-effectiveness in terms of infrastructure deployment. More interestingly, recent advancements in satellite communications using FSO links promise the future of a global QKD network for highly secure applications. This paper reviews the development of QKD over FSO for both terrestrial and satellite channels, which highlights the most up-to-date QKD protocols. Owing to how the information is encoded, different QKD protocols are classified into technology-focused categories, where their properties are reviewed and compared. The feasibility of current QKD protocols is then investigated with respect to its specific application scenarios for terrestrial and satellite FSO links, equipped with results from both theoretical and experimental studies. Based on the latest free-space QKD achievements, novel perspectives for future developments and challenges to enhance the secrecy performance and reduce implementation cost are then summarized and comprehensively discussed. The potential combination of QKD and physical layer cryptography for the newly emerging wireless mobile communications networks involved with unmanned aerial vehicles (UAV) is also introduced.
We devoted to analyzing information transfer in quantum channels in terms of the performance of quantum key distribution (QKD) free-space optical (FSO) communication systems through Bennett and Brassard 84 (BB84) protocol by taking into account the combined effect of attenuation, turbulence, pointing error, and angle of arrival (AOA) fluctuations. Path loss is modeled by Beer-Lambert law, and the turbulent channel is assumed to be Fisher-Snedecor F distributed. The pointing error and AOA fluctuations are modeled by Hoyt and Rayleigh distributions, respectively. The error and sift probabilities, quantum bit error rate, and secret key rate of a QKD FSO system are obtained in analytical form, and results are presented depending on various parameters. It is shown that increased beam waist, beam deviation, AOA fluctuations, and propagation distance cause performance degradation and less secure information transmission. However, an increase in the ratio of horizontal and vertical beam misalignments, field of view, average photon number per pulse, visibility of the atmospheric environment, and optical beam wavelength impact the performance of QKD FSO systems positively. The effect of the turbulence structure constant is observed to be modest on the performance of the QKD FSO system.
The purpose of this research is to analyze and explore quantum theorems as a wireless telecommunications security solution in the future. This study uses a quantitative approach through simulation and performance analysis of QKD systems in wireless channels, by combining literature studies and comparative analysis between QKD and PQC. Meanwhile, the wireless communication simulation model, using the QKD protocol and PQC algorithm, with Free Space Optics (FSO), WiFi, and LiFi-based network scenarios. The simulation was carried out using MATLAB. This study is based on QKD, which uses BB84 and CV-QKD protocols on FSO 100m and LiFi wireless channels. And based on PQC, which uses the Kyber algorithm, with AES authentication for communication. Both models were simulated and tested based on the parameters of Quantum Bit Error Rate, Key Generation Rate, latency, and resistance to third-party attacks (wiretapping detection). Furthermore, the analysis was carried out quantitatively and comparatively to compare the performance of QKD and PQC based on the QBER, latency, KGR, and wiretapping detection of implementation. This analysis are combined with data based on the literature, to formulate optimal implementation strategies in the context of future wireless networks. The results indicate that QKD, specifically CV-QKD, has significant potential for use in attack-sensitive wireless communications, such as military, government, and industrial applications. However, this model requires more complex hardware and infrastructure investments in its implementation. Meanwhile, PQC offers a more ready-to-use and cost-effective solution for everyday communications that remains resilient to quantum attacks.
Unmanned aerial vehicles (UAV) based on free-space optical (FSO) systems combine the benefits of both the high data rate of the FSO and the mobility of UAV. However, cumulative effects of laser beam divergence and turbulence-induced fading on the received irradiance in the FSO link might allow an external eavesdropper located near the authorized receiver to break the transmission under certain conditions. Quantum key distribution (QKD) is a technique of secure communication that employs quantum mechanics-based cryptography principles. A combination of a continuous-variable quantum key distribution (CV-QKD) and Gaussian modulation of quantum coherent states (GMCS) enables a relatively secure communication system against collective attacks over FSO transmission links. However, the performance is restricted and degraded due to the influence of atmospheric turbulence and excess noise. This paper aims to evaluate the performance of a secured UAV-based FSO system utilizing prepare and measure CV-QKD protocol based on GMCS under collective attack in terms of quantum bit error rate (QBER), outage probability, and secret key rate (SKR) considering the impairments of the FSO channel, link budget, deviations in the position and attitude angles of the UAV, channel fluctuating transmittance, and excess noise. The system parameters, including transmit power, receiver’s field-of-view, and beam divergence angle, are optimized to satisfy the system’s design criteria of threshold-QBER=10−3and threshold outage probability=10−2. The proposed system tolerates boresight displacement up to 7 cm with the optimized values. The Closed-form expressions and analytical results are confirmed by Monte-Carlo simulations.
Abstract With increasing demands for secure high-speed wireless communications, integration of quantum key distribution (QKD) into light fidelity (LiFi) systems is a promising method for boosting data confidentiality in optical wireless networks. The BB84 protocol and Mach–Zehnder modulator (MZM) are utilized with a pump-assisted continuous wave laser at 1,550 nm and polarization control components to encode quantum states onto photons. They are transmitted on free space optical (FSO) links with a length ranging from 2 km to 8 km and received using Avalanche photodiodes (APDs) and optical filters. Performance analysis conducted using bit error rate (BER) and Q-factor analysis. BER maintained at zero across all tested configuration and transmission distance up to 8 km indicating excellent signal integrity and security. A highest Q-factor achieved a maximum of 3,055.9, which ensures signal integrity and low interference noise. The system operates at a simulated data rate of 10 Gbps, suitable for high speed optical wireless communication. Consistently high eye height (∼172,210 units) and stable decision thresholds confirm minimal inter-symbol interference and accurate symbol recognition. And the Poincaré sphere showed even polarization stability for different optical power levels. This work presents a simulation-based implementation of a polarization encoded QKD system over a LiFi-enabled FSO communication channel, aiming to enhance secure optical wireless communication. Calculated based on quantum bit error rate (QBER) and included in the theoretical analysis to demonstrate practical secure throughput.