Performance evaluation of the physical layer security using artificial noise and relay station

In the physical layer security (PLS), the beam forming with multiple antennas enhances the received signal power at the legitimate user but suppresses it at the other users. The other users hardly demodulate the information without the bit error. However, if the channel state between the legitimate user and the other one is highly correlated, it is possible for the other users to demodulate the information signal. This paper proposes the novel secure communication system with utilizing the artificial noise and the relay station. When the legitimate user emits the artificial noise, the relay station receives the information bearing signal and the artificial noise. The other users cannot demodulate the information due to the interference of artificial noise. After the relay forwards the combined signal between the information bearing signal and the artificial noise to the legitimate user, the artificial noise is removed from the forwarded signal by the legitimate user. As a result, the legitimate user can demodulate the information. Therefore, the secure wireless communication can be constructed. This paper evaluates the secure capacity for the various location of eavesdropper and clarifies the validity of proposed system.