A physical layer security transmission protocol in a two-hop relay system is studied. All nodes are equipped with an antenna and have the ability of energy harvesting. There are direct links between the source node and the eavesdropper as well as the relay node and the eavesdropper. Each transmission time slot is divided into two stages, which are respectively used for energy harvesting and data transmitting. The energy harvested is used to send data. The amplify-and-forward protocol is adopted, and the destination node sends artificial noise to protect the information transmitted in the first and second hop. To maximize the secrecy rate, iterative algorithm is used to optimize two variables of the time for energy harvesting and the power of artificial noise. Simulation results show that the optimization algorithm is accurate and the cooperative jamming can effectively improve the secrecy rate. Considering that eavesdropper can intercept the information transmitted in the two hops, the proposed scheme is more practical and can solve a complicate optimization problem.
MUKHERJEE A, FAKOORIAN S, HUANG J, et al. Principles of physical layer security in multiuser wireless networks: A survey[J]. IEEE Communications Surveys & Tutorials, 2014, 16(3): 1550-1573. doi: 10.1109/SURV.2014. 012314.00178.
[2]
BASSILY R, EKREM E, HE X, et al. Cooperative security at the physical layer: A summary of recent advances[J]. IEEE Signal Processing Magazine, 2013, 30(5): 16-28. doi: 10.1109/ MSP.2013.2260875.
[3]
GOEL S and NEGI R. Guaranteeing secrecy using artificial noise[J]. IEEE Transactions on Wireless Communications, 2008, 7(6): 2180-2189. doi: 10.1109/TWC.2008.060848.
[4]
HAN B, LI J, SU J S, et al. Secrecy capacity optimization via cooperative relaying and jamming for WANETs[J]. IEEE Transactions on Parallel and Distributed Systems, 2015, 26(4): 1117-1128. doi: 10.1109/TPDS.2014.2316155.
[5]
PARK K H, WANG T, and ALOUINI M S. On the jamming power allocation for secure amplify-and-forward relaying via cooperative jamming[J]. IEEE Journal on Selected Areas in Communications, 2013, 31(9): 1741-1750. doi: 10.1109/JSAC. 2013.130908.
[6]
HAGGSTROM F, GUSTAFSSON J, and DELSING J. Energy harvesting technologies for wireless sensors in rotating environments[C]. IEEE Emerging Technology and Factory Automation (ETFA), Barcelona, 2014: 1-4. doi: 10.1109/ETFA.2014.7005364.
[7]
VALENTA C R and DURGIN G D. Harvesting wireless power: survey of energy-harvester conversion efficiency in far-field, wireless power transfer Systems[J]. IEEE Microwave Magezine, 2014, 15(4): 108-120. doi: 10.1109/MMM.2014. 2309499.
[8]
LI Q, MA W K, and SO A M C. Robust artificial noise-aided transmit optimization for achieving secrecy and energy harvesting[C]. IEEE International Conference on Acoustic, Speech and Signal Processing (ICASSP), Florence, 2014: 1596-1600. doi: 10.1109/ICASSP.2014.6853867.
XIE G F. The general formula of real coefficient equations four[OL]. http://wenku.baidu.com/link?url=D8kKnPDyfV fUbp7FlkM6PV484bd_ikEPvZnHkgwquiqapU4rlbgxUzsF1 M9ck3puagGEmFeQAn3A8Du_up4cvW0bRQQkRXj5jHhwrSrrdi_, 2013.
[10]
LEONARD E D. Introduction to the Theory of Algebraic Equations[M]. New York: Rough Draft Printing, 1988: 67-72.
FAN S J. A new extracting formula and a new distinguishing means on the one variable cubic equation[J]. Journal of Hainan Normal University (Natural Science), 1989, 2(2): 91-98.
[12]
ZHU F, GAO F, ZHANG T, et al. Physical-layer security for full-duplex communications with self-interference mitigation [J]. IEEE Transactions on Wireless Communications, 2016, 15(1): 329-340. doi: 10.1109/TWC.2015.2472527.
