Antenna selection in switched phased array architecture for secure millimeter wave communication

Compared to traditional antenna arrays system, large-scale antenna arrays with multiple transmit antennas can achieve more accurate beam control ability, and decrease sidelobe leakage. However, sensitive eavesdropping receiver can still receive sidelobe signals and recover it, resulting in the unsafe transmission of information. For secure transmission, traditional directional modulation modulate signals in the RF end, but increasing system complexity. In this paper, we use switched phased array transmission architecture in millimeter-wave frequencies to study physical layer security through antenna selection, which disturb undesired direction constellation and have no effect in desired direction. We also proposed an antenna selection algorithm based on iterative fast Fourier transform (FFT) technique, which selects optimized antenna structure with a low sidelobe to constitute codebook for antenna switching. Compared with the traditional genetic algorithm, the proposed algorithm has lower sidelobe level and computational complexity. The simulation results verify the feasibility and effectiveness of the proposed scheme and algorithm.