Robust Energy Efficient Beamforming in MISOME-SWIPT Systems With Proportional Secrecy Rate

TL;DR

This paper proposes robust beamforming and artificial noise design strategies to maximize secrecy energy efficiency in MISOME-SWIPT systems with imperfect channel information, balancing performance and computational complexity.

Contribution

It introduces a novel SEE maximization framework for MISOME-SWIPT systems considering imperfect CSI, with convex reformulation and suboptimal heuristic solutions.

Findings

Optimal solution achieves highest secrecy energy efficiency.

Suboptimal solutions offer reduced complexity with acceptable performance.

Numerical results confirm effectiveness of proposed algorithms.

Abstract

The joint design of beamforming vector and artificial noise covariance matrix is investigated for the multiple-input-single-output-multiple-eavesdropper simultaneous wireless information and power transferring \mbox{(MISOME-SWIPT)} systems. In the MISOME-SWIPT system, the base station delivers information signals to the legitimate user equipments and broadcasts jamming signals to the eavesdroppers. A secrecy energy efficiency (SEE) maximization problem is formulated for the considered \mbox{MISOME-SWIPT} system with imperfect channel state information, where the SEE is defined as the ratio of sum secrecy rate over total power consumption. Since the formulated SEE maximization problem is non-convex, it is first recast into a series of convex problems in order to obtain the optimal solution with a reasonable computational complexity. Two suboptimal solutions are also proposed based on the heuristic beamforming techniques that trade performance for computational complexity. In addition, the analysis of computational complexity is performed for the optimal and suboptimal solutions. Numerical results are used to verify the performance of proposed algorithms and to reveal practical insights.