Optimal Transmit Beamforming for Secure SWIPT in Heterogeneous Networks

TL;DR

This paper develops a beamforming strategy using artificial noise to enhance security and energy harvesting in a two-tier heterogeneous network with SWIPT, optimizing secrecy rate under practical constraints.

Contribution

It introduces a novel SCA-based algorithm for secure beamforming in heterogeneous networks with SWIPT, addressing non-convex optimization challenges.

Findings

Proposed algorithm converges reliably and efficiently.

Enhanced secrecy rate performance demonstrated through simulations.

Effective joint optimization of security and energy harvesting constraints.

Abstract

This letter investigates the artificial noise aided beamforming design for secure simultaneous wireless information and power transfer (SWIPT) in a two-tier downlink heterogeneous network, where one femtocell is overlaid with one macrocell in co-channel deployment. Each energy receiver (ER) in femtocell can be considered as a potential eaves- dropper for messages intended for information receiver (IR). Our objective is to maximize the secrecy rate at IR subject to the signal-to-interference-plus noise ratio (SINR) requirements of macro users (MUs), transmit power constraint and energy harvesting constraint. Due to the non-convexity of the formulated problem, it cannot be solved directly. Thus, we propose a novel reformulation by using first-order Taylor expansion and successive convex approximation (SCA) techniques. Furthermore, an SCA-based algorithm with low complexity is proposed to arrive at provably convergent solution. Finally, numerical results evaluate the performance of the proposed algorithm.