Polarization Sensitive Array Based Physical-Layer Security

We propose a framework exploiting the polarization sensitive array (PSA) to improve the physical layer security of wireless communications. Specifically, the polarization difference among signals is utilized to improve the secrecy rate of wireless communications, especially when these signals are spatially indistinguishable. We firstly investigate the PSA based secure communications for point-to-point wireless systems from the perspectives of both total power minimization and secrecy rate maximization. We then apply the PSA based secure beamforming designs to relaying networks. The secrecy rate maximization for relaying networks is discussed in detail under both the perfect channel state information and the polarization sensitive array pointing error. In the later case, a robust scheme to achieve secure communications for relaying networks is proposed. Simulation results show that the proposed PSA based algorithms achieve lower total power consumption and better security performance compared to the conventional scalar array designs, especially under challenging environments where all received signals at destination are difficult to distinguish in the spatial domain.