Secure Downlink Transmission Strategies against Active Eavesdropping in燦OMA Systems: A Zero-Sum Game Approach

Non-orthogonal multiple access technology (NOMA), as a potentially promising in the 5G/B5G era, suffers from ubiquitous security threats due to broadcast nature of wireless medium. In this paper, we focus on artificial-signal-assisted and relay-assisted secure downlink transmission schemes against external eavesdropping context physical layer security, respectively. To characterize non-cooperative confrontation around secrecy rate between legitimate communication party eavesdropper, their interactions are modeled two-person zero-sum game. The existence Nash equilibrium proposed game models is proved, pure strategy mixed-strategy profiles two solved analyzed, numerical simulations conducted validate analytical results, show that improve further enhance performance NOMA systems.