Secure Beamforming for MIMO Broadcasting With Wireless Information and Power Transfer

• Published in: IEEE transactions on wireless communications Vol. 14; no. 5; pp. 2841 - 2853
• Main Authors: Shi, Qingjiang, Xu, Weiqiang, Wu, Jinsong, Song, Enbin, Wang, Yaming
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2015; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithm design and analysis; Algorithms; Array signal processing; Beamforming; block coordinate descent; Broadcasting; Communication system security; Design engineering; Energy harvesting; Energy transmission; Erbium; Maximization; Receivers; Receivers & amplifiers; secrecy rate maximization; semidefinite relaxation; Wireless communication; wireless information and power transfer; semidefinite relaxation; block coordinate descent; Beamforming; secrecy rate maximization; wireless information and power transfer (WIPT)
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2015.2395414

This paper considers a basic MIMO information-energy broadcast system, where a multi-antenna transmitter transmits information and energy simultaneously to a multi-antenna information receiver and a dual-functional multi-antenna energy receiver which is also capable of decoding information. Due to the open nature of wireless medium and the dual purpose of information and energy transmission, secure information transmission while ensuring efficient energy harvesting is a critical issue for such a broadcast system. Providing that physical layer security techniques are adopted for secure transmission, we study beamforming design to maximize the achievable secrecy rate subject to a total power constraint and an energy harvesting constraint. First, based on semidefinite relaxation, we propose global optimal solutions to the secrecy rate maximization (SRM) problem in the single-stream case and a specific full-stream case. Then, we propose inexact block coordinate descent (IBCD) algorithm to tackle the SRM problem of general case with arbitrary number of streams. We prove that the IBCD algorithm can monotonically converge to a Karush-Kuhn-Tucker (KKT) solution to the SRM problem. Furthermore, we extend the IBCD algorithm to the joint beamforming and artificial noise design problem. Finally, simulations are performed to validate the effectiveness of the proposed beamforming algorithms.