Stackelberg game for secure CR-NOMA networks against internal eavesdropper

The combination of Cognitive Radio with Nonorthogonal Multiple Access (CR-NOMA) has enormous potential interest to improve spectral efficiency and increase system capacity in future wireless communication networks. Hence, according to the broadcast nature of the CR-NOMA wireless channel, handling the confidentiality of information is one of the most important requirements of the network. In this paper, Physical Layer Security (PLS) against internal Eavesdropper (Eve) is investigated by the CR-NOMA under the limitations of joint delay and confidentiality rate. First, initial power allocation for Secondary User (SU) based on the Primary User (PU) interference threshold is constructed. Then, a multi-objective problem based on different SUs demands is formulated based on Stackelberg game modeling. After that, the Stackelberg Equilibrium (SE) is studied and explored. At the final stage, an overall algorithm has been proposed whereby SE strategies are frequently updated to find the best parameters for the proposed system model. The simulation results show the superiority of the proposed scheme in achieving a higher average utility function, spectral efficiency, fairness index, up to 44%, 90%, and 54.7%, respectively, and reliability compared to the conventional scheme.