Secrecy Performance Analysis of Cooperative NOMA with AF and DF Protocol over Rayleigh Channel

The article examined the physical layer security of cooperative non-orthogonal multiple access (NOMA) network over Rayleigh fading channels by considering one eavesdropper. Relaying techniques like decode-and-forward (DF) and amplify-and-forward (AF) protocols are analyzed. The secrecy rate and secrecy outage probability of the system considering NOMA-AF and NOMA-DF systems were derived. Two cases were considered for the analysis, one system model where a near user operates as relay, forwarding the signal to far user; another where a relay is used in forwarding the signal to both users. Simulation results were obtained for different values of power allocation coefficients. These results show that the system model proposed in case 2 provides a better secrecy performance result than NOMA based models proposed in case 1 under both relaying techniques.