Secured Full-Duplex UAV-Aided Spectrum-Sharing Network Based on NOMA

Non-Orthogonal Multiple Access (NOMA) has emerged as an effective approach for improving spectral efficiency. In addition, Unmanned Aerial Vehicle (UAV)-aided communication offers rapid deployment and flexibility in challenging environments. Studying physical layer security in these scenarios is crucial to protect sensitive data from eavesdropping in spectrum-sharing networks. Nonetheless, there is limited research on comprehensive secrecy analysis in NOMA-based spectrum-sharing networks, particularly in the context of full-duplex UAV-assisted scenarios. In this paper, we investigate the secrecy performance of a UAV-aided and full-duplex NOMA-based spectrum-sharing network. The system primarily involves a primary source communicating with a full-duplex secondary source, which then simultaneously relays combined data from both sources to the primary and secondary receivers. Considering the susceptibility of both transmission stages to an external eavesdropper, the secondary source employs artificial jamming to enhance secrecy for both primary and secondary users. We analytically derive the ergodic secrecy achievable rate (ESAR) for the primary and secondary networks. The closed-form expressions are obtained by characterizing the channels’ probabilistic nature while considering the Nakagami-m fading properties of each channel. Through our analysis and Monte Carlo simulations, we demonstrate that our proposed scheme achieves a positive ESAR and outperforms benchmark schemes relying on OMA.