LAUSR

This letter considers a new secure communication scenario where a full-duplex transmitter (Alan) needs to transmit confidential information to a half-duplex receiver (Bob), with an eavesdropper (Eve) that tries to overhear the confidential information. For realizing the secure communication, we design an effective artificial-noise-aided secure scheme (ANAS) which is composed of two phases’ transmissions: in Phase 1, Alan and Bob transmit two independent artificial noises (ANs) simultaneously, while in Phase 2, Alan superimposes the AN received in Phase 1 with its confidential signal and sends out the mixed signal. Since the superimposed AN by Alan in Phase 2 can be effectively cancelled by Bob while remains an interference to Eve, a secrecy rate could then be achieved. Importantly, we derive the approximate closed-form solutions of the average secrecy rate and secrecy outage probability of ANAS under a Rayleigh block-fading channel. Numerical results show that the secrecy rate of ANAS is about twice higher than the benchmark scheme, even though in ANAS half of the time is used to transmit ANs.