Joint random mapping and artificial noise insertion for securing GPSM access in correlated eavesdropper channels

This paper proposes combined precoding and artificial noise-insertion scheme to enhance the secrecy of generalized precoded spatial modulation when the wiretap channel is partially correlated with the legitimate channel. It is shown that randomizing the modulated and spatial symbols prior to artificial noise insertion can significantly enhance secrecy even with a highly correlated eavesdropper channel. The proposed scheme exploits the channel state information (CSI) of the legitimate channel without requiring knowledge of the eavesdropper channel. The security of the proposed system depends on the amount of power allocation and the number of active receive antennas. Simulation results validate the proposed security scheme and show that the hybrid approach proposed outperforms the one that relies on artificial noise transmission.