Secrecy Rate Optimization for RF Powered Two-Hop Untrusted Relay Networks with Non-Linear EH Model

Xiaochen LIU  Yuanyuan GAO  Nan SHA  Guozhen ZANG  Kui XU  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E103-A   No.1   pp.215-220
Publication Date: 2020/01/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.2019CIL0001
Type of Manuscript: Special Section LETTER (Special Section on Cryptography and Information Security)
RF powered networks,  non-linear EH model,  untrusted relay,  secrecy rate,  physical layer security,  

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In this letter, we investigate the secure transmission in radio frequency (RF) powered two-hop untrusted relay networks, where the source node and untrusted relay are both wireless powered by an RF power supplier. Specifically, considering the non-linear energy-harvesting (EH) model, the two-process communication protocol is proposed. The secrecy rate is maximized by jointly designing the beamforming vector at source and beamforming matrix at relay, under the constraints of transmit power at RF power supplier and destination. The secrecy rate maximization (SRM) is non-convex, hence we propose an alternative optimization (AO) based iterative algorithm. Numerical results demonstrate that the proposed scheme can significantly increase the secrecy rate compared to the baseline schemes.