Robust Artificial-Noise-Aided Beamforming in Physical Layer Security

Considering that an illegitimate user wants to eavesdrop on the messages which are broadcasted from the base station to two legitimate users, we study the robust artificial-noise aided optimal beamforming scheme where imperfect channel state information(CSI) is assumed. Our aim is to maximize the sum of the achievable secrecy rate, subject to the sum of the power. We propose to apply S-procedure to reformulate it and employ an alternating optimization(AO) algorithm to solve the problem. Simulation results show that our proposed scheme is superior to the non-robust one.