Research On Physical Layer Security In Simultaneous Wireless Information And Power Transfer

Simultaneous wireless information and power transfer(SWIPT)can provide stable and continuous power supply for energy-constrained nodes while maintaining effective communication.However,it still faces the security threat of information leakage as an extension of wireless communication.The physical layer security,which supplements to high-level encryption methods,can make use of the “fingerprints” of wireless channels to protect the communication from being eavesdropped with low complexity,which provides a novel approach for safeguarding SWIPT systems.Since the research on physical layer security technology in SWIPT has just started and related works are still relatively limited,there still remain several problems that need to be resolved: 1)The existing transmission schemes have not fully considered the difference in security requirements of information transmission and power transfer;2)There lack transmission schemes for securing the transmission of uplinks in SWIPT systems;3)The research on multi-cell SWIPT networks has not considered the energy efficiency and the average performance of network.Driven by the above,this paper conducts research on the physical layer security in SWIPT systems supported by the National Natural Science Foundation of China and the National High-Tech Research and Development Program Fund.Detailed speaking,the main content of this paper includes three parts as follows.1.A secure transmission scheme based on dynamic “information-power” switching(DIPS)is proposed for the downlink in a single-cell coverage scenario.Starting with the different security requirements of information transmission and power transfer,we accomplish the scheme design according to the time-varying characteristics of wireless channels.In the scheme,the transmitter acquires the channel state through estimation,and dynamically adjusts the content of transmit signal to perform the transmission of information and power in an opportunistic manner.Simulation results illustrate that the downlink secrecy throughput can be promoted by at least 36.9%.2.An on-off transmission scheme based on energy threshold is proposed for safeguarding the uplink in a single cell coverage scenario.Considering the impact of transmit power on transmission quality,secrecy performance as well as the energy constraint of users,we introduce an energy threshold which allows the user to grasp the uplink transmission status flexibly,and the scheme increases the secrecy performance at cost of bringing certain transmission delay.Simulation results illustrate that the uplink secrecy throughput can be promoted by at least 47.7%.3.A multi-cell coordinated beamforming scheme based on secrecy energy efficiency fairness is proposed for a multi-cell coverage scenario.Considering the aim of achieving green communications and the target of promoting the average secrecy performance,the beamforming and artificial noise vectors are designed by maximizing the minimal secrecy energy efficiency in the network subject to transmit power constraints and Quality of Service(QoS)constraints.Simulations results illustrate that the secrecy energy efficiency fairness can be effectively improved.