Robust AN-Aided Beamforming and Power Splitting Design for Secure MISO Cognitive Radio With SWIPT

摘要

A multiple-input single-output cognitive radio downlink network is studiedwith simultaneous wireless information and power transfer. In this network, asecondary user coexists with multiple primary users and multiple energyharvesting receivers. In order to guarantee secure communication and energyharvesting, the problem of robust secure artificial noise-aided beamforming andpower splitting design is investigated under imperfect channel stateinformation (CSI). Specifically, the transmit power minimization problem andthe max-min fairness energy harvesting problem are formulated for both thebounded CSI error model and the probabilistic CSI error model. These problemsare non-convex and challenging to solve. A one-dimensional search algorithm isproposed to solve these problems based on ${\cal S}\text{-Procedure} $ underthe bounded CSI error model and based on Bernstein-type inequalities under theprobabilistic CSI error model. It is shown that the optimal robust securebeamforming can be achieved under the bounded CSI error model, whereas asuboptimal beamforming solution can be obtained under the probabilistic CSIerror model. A tradeoff is elucidated between the secrecy rate of the secondaryuser receiver and the energy harvested by the energy harvesting receivers undera max-min fairness criterion.