Secure transmission with artificial noise in millimeter wave systems

The use of millimeter wave is an effective way to meet the data traffic demand of the 5G wireless communication system. For the new propagation characteristics of millimeter wave, in this paper, we study the secure transmission with artificial noise under slow fading channels considering multipath propagation in millimeter wave systems. Firstly, when partial eavesdropper's channel state information is known at the transmitter, an artificial noise transmission strategy which depends on directions of the destination's and the eavesdropper's propagation paths is proposed. Then we analyze the secrecy outage probability (SOP) through an on-off transmission scheme. Furthermore, we minimize the SOP subject to a secrecy rate constraint and derive a closed-form optimal power allocation between the information bearing signal and artificial noise. Numerical results are provided to show the superiority of the proposed scheme.