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International Conference on Recent Advances in Electrical, Electronics, Ubiquitous Communication, and Computational Intelligence (RAEEUCCI)

Design and Analysis of Adaptive Quantum Key Distribution (QKD) for Wireless Communication

Vijayashanthi R S, Arunaachalam G S, Hariharan N, Lingeswaran A, Pawan Sidharth R G

Published Apr 22, 2026• 0 citations
Publisher

Abstract

This paper presents a new adaptive QKD system with a Genetic Algorithm optimizer. The issue of security in modern wireless network is of alarming significance, especially to freespace optical connections in which the dynamics in the environment are hazardous with regard to confidentiality. Quantum Key Distribution (QKD) is now available over air channels and can be used to secure a key exchange but it is highly impaired by atmospheric turbulence, beam misalignment, background radiation, path loss, and scintillation and pointing errors. These weaknesses elevate Quantum Bit Error Rate (QBER) and slow down secret key rate, making it impractical to deploy. In this paper, we present a new adaptive QKD system with a Genetic Algorithm (GAD) optimizer adjusting decoy intensities, the probability of choice of a basis in selecting a detector, detector threshold, and privacy amplification rates dynamically. The active control of channels under different atmospheric conditions by continuous monitoring of channels with pilot frames and the QBER feedback allows intelligent parameter reconfiguration. The performance of the simulation using various turbulence regimes shows that the proposed adaptive one boosts the average secret key rate by The simulation results show a 25-40% improvement in secret key rate, reduced QBER, and increased secure transmission range as well as the range and the resilience of transmission, which confirm the efficiency and practical importance of the proposed adaptation technique.

DOI
10.1109/raeeucci67649.2026.11504964

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This paper presents a new adaptive QKD system with a Genetic Algorithm optimizer. The issue of security in modern wireless network is of alarming significance, especially to freespace optical connections in which the dynamics in the environment are hazardous with regard to confidentiality. Quantum Key Distribution (QKD) is now available over air channels and can be used to secure a key exchange but it is highly impaired by atmospheric turbulence, beam misalignment, background radiation, path loss, and scintillation and pointing errors. These weaknesses elevate Quantum Bit Error Rate (QBER) and slow down secret key rate, making it impractical to deploy. In this paper, we present a new adaptive QKD system with a Genetic Algorithm (GAD) optimizer adjusting decoy intensities, the probability of choice of a basis in selecting a detector, detector threshold, and privacy amplification rates dynamically. The active control of channels under different atmospheric conditions by continuous monitoring of channels with pilot frames and the QBER feedback allows intelligent parameter reconfiguration. The performance of the simulation using various turbulence regimes shows that the proposed adaptive one boosts the average secret key rate by The simulation results show a 25-40% improvement in secret key rate, reduced QBER, and increased secure transmission range as well as the range and the resilience of transmission, which confirm the efficiency and practical importance of the proposed adaptation technique.
We optimize secret key rates (SKRs) of weak coherent pulse (WCP)-based quantum key distribution (QKD) over time-varying free-space optical channels affected by atmospheric turbulence. The random irradiance fluctuation due to scintillation degrades the SKR performance of WCP-based QKD, and to improve the SKR performance, we propose an adaptive scheme in which transmit power is changed in accordance with the channel state information. We first optimize BB84 and decoy state-based QKD protocols for different channel transmittances. We then present our adaptation method, to overcome scintillation effects, of changing the source intensity based on channel state predictions from a linear autoregressive model while ensuring the security against the eavesdropper. By simulation, we demonstrate that by making the source adaptive to the time-varying channel conditions, SKRs of WCP-based QKD can be improved up to over 20%.
Quantum key distribution (QKD) provides information-theoretic security and satellite-based quantum key distribution (SatQKD) has demonstrated the potential to extend this communication security to intercontinental scales. However, atmospheric turbulence induces significant distortion in the spatial distribution of received optical beams, while background noise remains approximately uniform across the detector plane. As a result, single-element qubit (quantum bit) detection can be frequently dominated by noise due to the random spatial pattern of the imaged wavefront, thereby degrading the system performance. To address this limitation, we propose to exploit the spatial degrees of freedom of single-photon detector arrays to reject the excessive noise while adapting to channel variations induced by turbulence. We develop a threshold-based selection method that only activates detector elements that have higher probability of registering qubits. We evaluate the performance of the proposed noise-rejection QKD schemes using Monte Carlo simulations considering the impact of diffraction and atmospheric turbulence on the transmitted optical beam in the presence of background and dark noise. The results show that, compared to conventional schemes, the proposed noise-rejection strategy effectively reduces the quantum bit error rate (QBER) and improves the secret key rate (SKR) performance, while the performance gains depend on the turbulence condition. These findings demonstrate the potential of adaptive array receiver design to enhance the robustness of the SatQKD system under realistic atmospheric conditions.
The unconditional security in the creation of cryptographic keys obtained by quantum key distribution (QKD) protocols will induce a quantum leap in free-space communication privacy in the same way that we are beginning to realize secure optical fiber connections. However, free-space channels, in particular those with long links and the presence of atmospheric turbulence, are affected by losses, fluctuating transmissivity, and background light that impair the conditions for secure QKD. Here we introduce a method to contrast the atmospheric turbulence in QKD experiments. Our adaptive real time selection (ARTS) technique at the receiver is based on the selection of the intervals with higher channel transmissivity. We demonstrate, using data from the Canary Island 143-km free-space link, that conditions with unacceptable average quantum bit error rate which would prevent the generation of a secure key can be used once parsed according to the instantaneous scintillation using the ARTS technique.
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.
Secure data transmission is essential in today's world, and quantum key distribution (QKD) is widely recognized as the technology of choice to enable information-theoretical secure symmetric key generation. While optical fibers are typically used as a transmission channel, wireless transmission offers the flexibility to reach every part of the Earth; moreover, for Earth-Satellite QKD, wireless communication naturally becomes a necessity. In this study, we deployed a fiber-wireless optical system that transmitted a 64-QAM 400 Gbps classical signal for high-rate data exchange and a 1 MHz quantum signal for QKD. The impact of turbulence in the quantum system is evaluated by transmitting single-polarization quantum states through a turbulent free-space channel and by calculating the respective intrinsic quantum bit error rate (QBER). From this, we estimate the system's secret key rate (SKR) and its dependence on turbulence. The effects of atmospheric turbulence on the optical wireless signal were emulated and investigated by using a custom-made atmospheric chamber to induce different turbulent scenarios. The atmospheric chamber allowed us to vary the turbulence in a Rytov variance range from 0.06 to 2.52. The classical signal showed an overall average reliability of 82% for the mentioned turbulence regimes. The results of the quantum signal showed that for Rytov variances up to 1.3, and under the conditions tested, secret key generation is possible, reaching a maximum SKR of 8.7×10−4\mathbf {\times 10^{-4}}×10−4bits per pulse during the produced turbulence regimes.
Quantum Key Distribution (QKD) can provide information-theoretically secure communications and is a strong candidate for the next generation of cryptography. However, in practice, the performance of QKD is limited by "practical imperfections" in realistic sources, channels, and detectors (such as multi-photon components or imperfect encoding from the sources, losses and misalignment in the channels, or dark counts in detectors). Addressing such practical imperfections is a crucial part of implementing QKD protocols with good performance in reality. There are two highly important future directions for QKD: (1) QKD over free space, which can allow secure communications between mobile platforms such as handheld systems, drones, planes, and even satellites, and (2) fibre-based QKD networks, which can simultaneously provide QKD service to numerous users at arbitrary locations. These directions are both highly promising, but so far they are limited by practical imperfections in the channels and devices, which pose huge challenges and limit their performance. In this thesis, we develop adaptive techniques with innovative protocol and algorithm design, as well as novel techniques such as machine learning, to address some of these key challenges, including (a) atmospheric turbulence in channels for free-space QKD, (b) asymmetric losses in channels for QKD network, and (c) efficient parameter optimization in real time, which is important for both free-space QKD and QKD networks. We believe that this work will pave the way to important implementations of free-space QKD and fibre-based QKD networks in the future.