Dual-Beam Directional Modulation Technique for Physical-Layer Secure Communication

A dual-beam directional modulation (DM) technique is proposed for physical-layer secure communication. The main idea is that the in-phase and quadrature (IQ) baseband signals are used to excite two different antennas unlike a traditional transmitter, which is used to excite the same antenna. In this way, the constellation points of the transmit signal maintain their positions as traditional digital modulation signal at the desired direction, but scramble in the phase at the undesired directions because of the transmit signal both modulated at the baseband and the antenna level. Simulation results show that this dual-beam DM technique offers a security transmission method for wireless communication.