This paper presents a performance evaluation of BB84 and SARG04 quantum key distribution (QKD) proto-cols in high-speed air-to-air communication scenarios using co-directional and anti-directional flight models. By integrating both classical and quantum models with QuTiP for simulating quantum states and noise channels, we analyze secure key rates and quantum bit error rates (QBER) under varying Mach numbers, azimuth angles, and boundary layer effects. Our results indicate that co-directional flights experience lower QBER and higher transmission efficiency compared to anti-directional flights due to reduced turbulence intensity. However, boundary layer-induced turbulence and Mach number variations significantly degrade the effective key rate in both models. The proposed evaluation scheme, leveraging QuTiP's quantum modeling capabilities, provides a comprehensive framework for optimizing airborne QKD systems for secure communication in dynamic flight conditions. Furthermore, the insights gained from this work can be extended to satellite-based communication networks, where similar dynamic conditions-such as relative motion, atmospheric disturbances, and line-of-sight sta-bility-pose significant challenges for secure quantum commu-nication.
This paper presents a performance evaluation of BB84 and SARG04 quantum key distribution (QKD) proto-cols in high-speed air-to-air communication scenarios using co-directional and anti-directional flight models. By integrating both classical and quantum models with QuTiP for simulating quantum states and noise channels, we analyze secure key rates and quantum bit error rates (QBER) under varying Mach numbers, azimuth angles, and boundary layer effects. Our results indicate that co-directional flights experience lower QBER and higher transmission efficiency compared to anti-directional flights due to reduced turbulence intensity. However, boundary layer-induced turbulence and Mach number variations significantly degrade the effective key rate in both models. The proposed evaluation scheme, leveraging QuTiP's quantum modeling capabilities, provides a comprehensive framework for optimizing airborne QKD systems for secure communication in dynamic flight conditions. Furthermore, the insights gained from this work can be extended to satellite-based communication networks, where similar dynamic conditions-such as relative motion, atmospheric disturbances, and line-of-sight sta-bility-pose significant challenges for secure quantum commu-nication.
Airborne platforms offer a potential solution to overcome the challenges of quantum key distribution (QKD) over long distances and in free space. However, the presence of boundary layer around high-speed flying vehicles can introduce unpredictable shifts and disturbances to transmitted photons, affecting their mode. In this article, we propose a performance evaluation scheme for air-to-air QKD with boundary layer effects. Our analysis compares the effects of the boundary layer at the receiver and at the transmitter on QKD performance, as well as an evaluation of two possible air-to-air QKD models. The results indicate that in the co-directional flight model, a particular azimuth can significantly increase the QBER when both ends are affected by the boundary layer, and photon deflection angles are larger when the transmitter is at a relatively low altitude.In the counter-directional flight model, the boundary layer around the aircraft may result in a maximum reduction in secure key rate by approximately 79.6% and introduce average channel loss of around 3.45 dB for transmitted photons. These findings highlight the importance of considering the boundary layer effects in air-to-air QKD and provide insights for the design and optimization of QKD systems in practical scenarios.
Airborne quantum key distribution (QKD) is now becoming a flexible bond between terrestrial fiber and satellite, which is an efficient solution to establish a mobile, on-demand, and real-time coverage quantum network. Furthermore, When the aircraft is flying at a high speed, usually larger than 0.3 Ma, the produced boundary layer will impair the performance of aircraft-based QKD. The boundary layer would introduce random wavefront aberration, jitter and extra intensity attenuation to the transmitted photons. However, previous airborne QKD implementations only considered the influences from atmospheric turbulence and molecular scattering, but ignored the boundary layer effects. In this article, we propose a detailed performance evaluation scheme of airborne QKD with boundary layer effects and estimate the overall photon transmission efficiency, quantum bit error rate and final secure key rate. Through simulations and modeling, in our proposed airborne QKD scenario, the boundary layer would introduce 3.5dB loss to the transmitted photons and decrease 70.7% of the secure key rate, which shows that the aero-optical effects caused by the boundary layer can not be ignored. With tolerated quantum bit error rate set to 10%, the suggested quantum communication azimuth angle between the aircraft and the ground station is within 60 degrees. Moreover, the optimal beacon laser module and adaptive optics module are suggested to be employed to improve the performance of airborne QKD system. Our detailed airborne QKD evaluation study can be performed to the future airborne quantum communication designs.
Airborne quantum key distribution (QKD) that can synergize with terrestrial networks and quantum satellite nodes is expected to provide flexible and relay links for the large-scale integrated communication network. However, the photon transmission rate would be randomly reduced, owing to the random distributed boundary layer that surrounding to the surface of the aircraft when the flight speed larger than Mach 0.3. Here, we investigate the airborne QKD performance with the BL effects. Furthermore, we take experimental data of supersonic BL into the model and compare the airborne QKD performance under different conditions. Simulation results show that, owing to the complex small-scale turbulence structures in the supersonic boundary layer, the deflection angle and correspondingly drifted offset of the beam varied obviously and randomly, and the distribution probability of photons are redistributed. And the subsonic and supersonic boundary layer would decrease ~35.8% and ~62.5% of the secure key rate respectively. Our work provides a theoretical guidance towards a possible realization of high-speed airborne QKD.
With the substantial progress of terrestrial fiber-based quantum networks and satellite-based quantum nodes, airborne quantum key distribution (QKD) is now becoming a flexible bond between terrestrial fiber and satellite, which is an efficient solution to establish a mobile, on-demand and real-time coverage quantum network. However, the boundary layer (BL) normally adhere to the surface of the aircraft when its speed is higher than Mach 0.3. The BL would change local refractive index and energy flux density drastically, thus lowering the coupling efficiency and infidelity of quantum states. Here, we investigate the airborne QKD performance with the BL effects, which has been rarely mentioned in existing research. Through simulations and modeling, we present the relation between divergence angle and secure key rate. With the increase of flight speed v, relative flight altitude h and the shortest projection distance d, the key-rate curve is obviously jitter, and the QKD performance is continuously reduced. Simulation results show that, under several typical circumstances, the BL will affect the communicating distance, the transmission efficiency and the generation of secure key rate in varying degrees, which is helpful for future airborne experimental designs.
Quantum Key Distribution (QKD) has emerged as a fundamentally secure approach to communication in the era of quantum computing, offering protection against threats posed to classical cryptographic schemes such as RSA and Diffie-Hellman. This thesis presents a comprehensive performance analysis of satellite-based QKD protocols, focusing on both prepare-and-measure and entanglement-based schemes under realistic atmospheric and operational conditions. The study begins by introducing the theoretical foundations of quantum communication, including qubits, entanglement, and quantum entropy, and motivates the need for satellite-based QKD to overcome the distance limitations of fiber-based systems. Subsequently, the thesis evaluates four prominent QKD protocols-BB84, B92, BBM92, and E91-using a circular beam propagation model that incorporates atmospheric effects such as diffraction, turbulence, attenuation, and pointing errors, along with environmental noise contributions for uplink and downlink. Comparative numerical simulations reveal that protocol performance is strongly influenced by channel asymmetries, beam propagation characteristics, and noise, providing guidance on optimal protocol selection for low Earth orbit (LEO) satellite links. The research further investigates high-dimensional (HD) QKD protocols, specifically HD-BB84 and HD-Extended B92, using the elliptic-beam approximation to account for turbulence-induced distortions for both uplink and downlink. Simulations under vary ing system dimensions, weather conditions, and zenith angles demonstrate that HD-BB84 achieves higher key rates, superior noise tolerance, and more favorable probability distributions of the key rate compared to HD-Extended B92, highlighting the advantages of high-dimensional encoding for robust satellite-based QKD.
Abstract With the substantial progress of terrestrial fiber-based quantum networks and satellite-based quantum nodes, airborne quantum key distribution (QKD) is now becoming a flexible bond between terrestrial fiber and satellite, which is an efficient solution to establish a mobile, on-demand, and real-time coverage quantum network. However, the random distributed boundary layer is always surrounded to the surface of the aircraft when the flight speed larger than 0.3 Ma, which would introduce random wavefront aberration, jitter and extra intensity attenuation to the transmitted photons. In this article, we propose a performance evaluation scheme of airborne QKD with boundary layer effects. The analyzed results about the photon deflection angle and wavefront aberration effects, show that the aero-optical effects caused by the boundary layer can not be ignored, which would heavily decrease the final secure key rate. In our proposed airborne QKD scenario, the boundary layer would introduce ∼3.5 dB loss to the transmitted photons and decrease ∼70.9% of the secure key rate. With tolerated quantum bit error rate set to 8%, the suggested quantum communication azimuth angle between the aircraft and the ground station is within 55∘. Furthermore, the optimal beacon laser module and adaptive optics module are suggested to be employed, to improve the performance of airborne QKD system. Our detailed airborne QKD performance evaluation study can be performed to the future airborne quantum communication designs.