Beamformer Design for Physical Layer Security in Dual-polarized Millimeter Wave Channels

We develop a beamforming scheme to enhance the physical layer security in dual-polarized millimeter wave (mmWave) systems. We aim to compute a transmit beamformer that maximizes the secrecy rate of the desired user. Assuming the transmitter has a statistical distribution of a dominant radio path, we compute a single-polarization beamforming vector that makes directional transmissions at mmWave frequencies more secure. Moreover, we propose a channel sounding scheme to obtain a weight vector that combines the dual-polarized antennas for improving the secrecy rate. Simulation results are presented to verify the secrecy rate performances of the proposed beamforming algorithm.