Efficient Transmission Solutions for MIMO Wiretap Channels With SWIPT

This letter studies transmit optimization in three-node multiple-input–multiple-output wiretap channels with simultaneous wireless information and power transfer. In particular, we address the transmit covariance optimization for the energy-harvesting maximization (EHM) problem under the constraint of secrecy rate and transmit power. The problem is nonconvex and hard to tackle. To circumvent it, we first resort to the Taylor series expansion to convert the problem into a convex optimization problem. Then, based on the analysis of its dual problem, an iterative algorithm, which includes a semiclosed-form solution, is proposed to handle this EHM problem. The scenario of imperfect channel state information of an energy receiver (the potential eavesdropper) is also considered. In this scenario, a Bernstein-type inequality-based iterative algorithm is proposed to deal with the challenging outage-constrained EHM problem. Simulation results demonstrate the efficiency of our proposed designs.