Transmit beamforming and cooperative jamming for MIMOME wiretap channels

Joint transmit beamforming and cooperative jamming for MIMOME (multiple-input multiple-output multi-antenna-eavesdropper) wiretap channel is studied, where the model consists of a transmitter, a friendly jammer, a receiver and an eavesdropper. The optimization problem of finding transmit and jamming covariances to maximize the secrecy rate is non-convex, and blindly searching will result in local optima. Because of the transmit beamforming, the MIMOME channel can be related to an effective MISOSE channel. Using this relation, we propose an iterative algorithm that in each iteration: 1) searches the jamming covariance for the effective MISOSE channel and 2) updates the effective MISOSE channel. Numerical results show that our proposed algorithm achieves higher objective whereas blind search is trapped at local optima. The proposed algorithm achieves higher secrecy rate than the existing artificial noise scheme.