  In this paper, we consider the secure transmission design for a
multiple-input single-output Femtocell overlaid with a Macrocell in co-channel
deployment. The Femtocell base station sends confidential messages to
information receiving Femtocell users (FUs) and energy signals to energy
receiving (ER) FUs while limiting the interference to Macrocell users (MUs).
The ER FUs have the potential to wiretap the confidential messages. By taking
fairness into account, we propose a sum logarithmic secrecy rate maximization
beamforming design problem under the interference constraints for MUs and
energy harvesting (EH) constraints for ER FUs. The formulated design problem is
nontrivial to solve due to the nonconvexity which lies in the objective and the
constraints. To tackle the design problem, a semidefinite relaxation and
successive convex approximation based algorithm is proposed. Simulation results
demonstrate the effectiveness of the proposed beamforming design.
