  In this letter, we study relay-aided networks with presence of single
eavesdropper. We provide joint beamforming design of the source and relay that
can minimize the overall power consumption while satisfying our predefined
quality-of-service (QoS) requirements. Additionally, we investigate the case
that the channel between relay and eavesdropper suffers from channel
uncertainty. Finally, simulation results are provided to verify the
effectiveness of our algorithm.
