Outage Constrained Robust Beamforming for Secure Broadcasting Systems With Energy Harvesting

• Published in: IEEE transactions on wireless communications Vol. 15; no. 11; pp. 7610 - 7620
• Main Authors: Zhu, Zhengyu, Chu, Zheng, Wang, Zhongyong, Lee, Inkyu
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Array signal processing; Beamforming; Broadcasting; Communication system security; Complexity; Constraints; Energy harvesting; Iterative algorithms; MISO (control systems); outage probability; Outages; physical-layer secrecy; Power transfer; Receivers; robust optimization; Robustness; Statistical analysis; successive convex approximation; SWIPT; Transmitters; Uncertainty; Wireless communication
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2016.2605102

In this paper, we investigate simultaneous wireless information and power transfer systems for multiuser multiple-input single-output secure broadcasting channels. Considering imperfect channel state information, we introduce a robust secure beamforming design, where the transmit power is minimized subject to the secrecy rate outage probability constraint for legitimate users and the harvested energy outage probability constraint for energy harvesting receivers. The original problem is non-convex due to the presence of the probabilistic constraints. With the aid of Bernstein-type inequalities, we transform the outage constraints into the deterministic forms. Based on a successive convex approximation (SCA) method, we propose a low-complexity approach, which reformulates the original problem as a second-order cone programming problem. Also, we prove the convergence of the SCA-based iterative algorithm. Simulation shows that the proposed scheme outperforms the conventional method with lower complexity.