Polarized spatial and directional modulation toward secure wireless transmission

Dear editor, Directional modulation(DM)has been developed as a promising physical layer security(PLS)technique.How-ever,most of the DM techniques cannot guarantee transmis-sion security when eavesdroppers and legitimate users share the same direction.In order to tackle this problem,a DM system with multiple distributed and cooperative receivers,namely DM-CR,was proposed in[1].Then the DM-CR and spatial modulation(SM)techniques were combined into a novel directional modulation(SDM)system[2],which not only maintains the secure transmission in DM-CR systems but also possesses SM's high-throughput characteristics.