Enhancing the Secrecy Performance and Secure Energy Efficiency of NOMA Systems Using RIS With Artificial Jamming

ABSTRACT This framework integrates reconfigurable intelligent surface (RIS) with artificial jamming (AJ) to enhance the security performance of nonorthogonal multiple access (NOMA) systems. To evaluate the security performance, the mathematical expressions for the average secrecy capacity (ASC), secrecy outage probability (SOP), and secure energy efficiency (SEE) are derived in two contexts, namely, the RIS‐Jammer‐NOMA system and the RIS‐Non‐Jammer‐NOMA system. Furthermore, to enhance the practicality of the proposed system, we evaluate the impact of imperfect cancellation of the AJ power on the legitimate users, considering imperfect successive interference cancellation (SIC). The numerical results demonstrate that the secrecy performance of the proposed system outperforms those of the non‐jammer system, the conventional relay‐assisted (R) system, and the orthogonal multiple access (OMA) system. Moreover, the effects of several key parameters, including the number of reflecting elements, jamming location, power allocation factors, and jamming cancellation at legitimate users, are thoroughly analyzed to characterize the system performance. Finally, Monte Carlo simulations are conducted to verify the accuracy of the derived expressions.