Performance evaluation and security analysis of ground-to-satellite FSO system with CVQKD protocol

This study evaluates the performance of a secure ground-to-satellite free-space optical (FSO) system using a bipolar pulse amplitude modulation over modulated gamma fading channel. A closed-form expression is derived for the joint probability of a satellite-based continuous-variable quantum key distribution (CV-QKD) protocol that uses dual-threshold detection. Furthermore, to study the system behaviour, closed-form expressions for quantum bit-error-rate (QBER) and quantum bitdiscard rate (QBDR) are given. The accuracy of the proposed derivations is validated using Monte-Carlo simulations and numerical analysis. The dual-threshold range is optimised to satisfy design criteria in terms of QBER and QBDR. Finally, a sufficient selection of transmitter and receiver parameters ensures a guarantee of system security. Additionally, the information capacity is maximised by a scaling coefficient of 0.3 × 10-6. © The Institution of Engineering and Technology 2020.