QSpace: Quantum Secured Key Distribution Scheme for Reliable Satellite Communication Underlying 5G

The paper proposes a novel scheme, QSpace for secured satellite communication. The scheme is designed to leverage seamless key distribution between satellites and Ground Stations (GS) based on the entanglement based Quantum Key Distribution (QKD) Ekert protocol, with quantum repeaters. Further, it integrates the Fifth Generation (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{5 G}$</tex>) ultra-Reliable Low Latency Communication (uRLLC) to enforce real-time latency constraints. To optimize the channel estimation and equalization, Convolutional Neural Network (CNN) is used to reduce the interference problem. A multi-objective optimization problem is formulated to balance key exchange rate, channel capacity, and latency while minimizing the Signal-to-Noise Ratio (SNR) and enhancing resilience against eavesdropping attacks. The optimization problem is solved using the iterative Stochastic Gradient Descent (SGD) to converge to optimal solution space with minimized cost function. Simulations demonstrate that the scheme achieves significant improvements, including a 30.23% reduction in Quantum Bit Error Rate (QBER), a 25.11% improvement in Frame Error Rate (FER), and a 35.21% decrease in Mean Squared Error (MSE) for 5G Physical Layer (PHY) channel estimation compared to existing approaches, affirming its potential to enhance secure real-time satellite communication.