Directional space-time modulation: A novel approach for secured wireless communication

The paper proposes a novel approach for securing the wireless communication by designing the signal in a way that makes its modulation format direction-dependent. The idea is to exploit the multi antennas at the transmitter to superimpose a space-time varying interfering component (at the modulation rate) while staying orthogonal to the desired receiver´s direction. Unlike conventional interference or artificial noise injection techniques, the proposed approach impedes an arbitrary eavesdropper from blindly separating the information data symbols from the injected interference due to its space-time varying nature.