Enhancing the physical layer security in IoT over mixed Rayleigh-Nakagami-m fading channels with untrustworthy relays

The Internet of Things (IoT) enables 5G communication, and it is widely used in many industries owing to its ability to connect a massive number of devices, process data intelligently, and enable remote control. However, the open nature of wireless communications makes information security and privacy critical concerns. In this paper, we investigate the issue of physical layer security (PLS) within a two-hop wireless cooperative network, where communication is facilitated by an untrusted relay. This investigation was performed over mixed Rayleigh-Nakagami-\(\varvec{m}\) fading channels in the presence of multiple non-colluding eavesdroppers. To improve the system’s security, we considered the incorporation of cooperative jamming and opportunistic relaying techniques. We formulated explicit equations for both the secrecy capacity and the secrecy outage probability within the system. Finally, by leveraging numerical results, simulations, and comparisons with existing works, we demonstrated the effectiveness of the proposed approach. This demonstration highlights that the suggested method serves as an effective method to enhance the security of IoT data collection processes, particularly in scenarios involving untrustworthy relays and highly risky eavesdropping threats.