Artificial Noise Aided Secure Communications for Cooperative NOMA Networks

Non-orthogonal multiple access (NOMA) has been envisioned as a promising technique to improve spectral efficiency and provide massive connectivity in future wireless networks. However, the inherited security issues with NOMA should be carefully addressed further exploit its potential benefits enabled As such, we consider cooperative network, where source uses simultaneously communicate multi-antenna near-user far-user. While directly communicating near-user, employs full-duplex (FD) decode-and forward (DF) relays establish communication far-user presence of passive eavesdropper. To address eavesdropping this propose new two-phase FD-based artificial noise (AN) scheme different relay selection techniques. In first phase, selected FD emits AN confuse eavesdropper while receiving superimposed signal from source. second performs exclusive OR (XOR) operation on both message intended before broadcasting resulting mixed signal. By utilizing null-space beamforming, self-interference cancellation techniques DF-XOR protocol, proposed can efficiently eliminated at well relay. cannot suppressed which serves purpose through degrading decoding capability We evaluate performance terms security-reliability trade-off (SRT). For AN-aided max-min partial techniques, theoretically derive exact asymptotic closed-form expressions outage probability intercept probability. Numerical results have provided validate derivations. addition, reveal that SRT improved by increasing number antennas relays.