Transmit Beamforming for Covert Wireless Communication with an Internal Eavesdropper

We investigate the problem of optimal transmit beamforming for maximizing the covert data rate subject to an upper bound for transmit power in a wireless communication system that contains an internal eavesdropper. To find an optimal beamforming vector, we formulate a non-convex optimization problem that takes into consideration the states of the transmitter-receiver channel and the transmitter-eavesdropper channel. We propose a novel algorithm that utilizes linear algebra and sequential convex optimization to efficiently obtain an adequate transmit beamforming vector. Simulation results show that the proposed approach could outperform two alternative schemes.