In wireless-powered cognitive radio networks, secure information transmission is of paramount importance for the primary system. This letter considers cooperation between a primary system and a wireless-powered secondary system. In particular, we focus on secure information transmission for the primary system when the secondary users (SUs) are the potential eavesdroppers. We aim to jointly design power splitting and secure beamforming to maximize the secondary system data rate subject to the secrecy QoS requirement of the primary system and the secondary transmitter (ST) power constraint. To solve this nonconvex problem, we propose a two-stage optimization approach. Simulation results demonstrate that our proposed scheme achieves a significant transmission rate of the secondary system while provides a high secrecy rate for the primary system compared to the scheme without energy harvesting.
['Li Jiang', 'Hui Tian', 'Cheng Qin', 'Stein Gjessing', 'Yan Zhang']
Secure Beamforming in Wireless-Powered Cooperative Cognitive Radio Networks