Joint relay and jammer selection for secure cooperative networks with a full-duplex active eavesdropper

In this study, the authors investigate the secure transmission of a cooperative network, in which a sourcecommunicates with a destination via multiple cooperative nodes in the presence of a full-duplex active eavesdropper, which canintercept the confidential signals and transmit jamming signals simultaneously. To safeguard the security of legitimatecommunication, two joint relay and jammer selection schemes are proposed according to the availability of the eavesdropper'schannel state information, namely, optimal relay and random jammer selection scheme and optimal relay and optimal jammerselection scheme. The authors first derive the exact closed-form expressions of the secrecy outage probability (SOP) fordifferent selection schemes. Aiming at minimising SOP, they then adopt the deep feedforward neural network to determine theoptimal power allocation between the selected relay and jammer. Further, the asymptotic expressions for SOP in the highsignal-to-noise ratio regime are derived. Numerical results verify the analysis and demonstrate the performance advantage ofthe proposed scheme over conventional relay selection scheme with optimal power allocation.