HAP-Aided Relaying Satellite FSO/QKD Systems for Secure Vehicular Networks

This paper proposes a high-altitude platform (HAP)-aided relaying satellite free-space optics (FSO) quantumkey distribution (QKD) system for the secure vehicular networks supporting unmanned vehicles (UAV) and regular vehicles. The subcarrier intensity modulation (SIM) binary phase shift keying (BPSK) and dual-threshold/direct detection (DT/DD) receiver are employed. The relaying HAP is equipped with optical amplifyand-forward (OAF) relaying node. We analytically derive the ergodic secret-key rate of the proposed system under the impact of atmospheric turbulence and other noises. Gaussian beam model is used to evaluate the impact of geometrical spreading on the signal received by the legitimate users and the probability of being eavesdropped. The numerical results confirm the feasibility of the proposed system.