  In this work, we maximize the secrecy rate of the wireless-powered untrusted
relay network by jointly designing power splitting (PS) ratio and relay
beamforming with the proposed global optimal algorithm (GOA) and local optimal
algorithm (LOA). Different from the literature, artificial noise (AN) sent by
the destination not only degrades the channel condition of the eavesdropper to
improve the secrecy rate, but also becomes a new source of energy powering the
untrusted relay based on PS. Hence, it is of high economic benefits and
efficiency to take advantage of AN compared with the literature. Simulation
results show that LOA can achieve satisfactory secrecy rate performance
compared with that of GOA, but with less computation time.
