Research On Physical Layer Against Eavesdropping Schemes In Full-duplex Relay Systems With Energy Harvesting

Due to the broadcastness and openness of wireless transmission media,information is easily leaked in the wireless transmission process.With the development of multi-antenna technology,signal processing technology and coding technology,the physical layer security technology in wireless communication systems is also constantly improving and developing.Simultaneous wireless information and power transfer(SWIPT)technology which can utilize the radio frequency signals to transmit information and energy is a new effective solution to the problem of energy supply in wireless device.In this paper,the transmission scheme of secrecy information in the full-duplex relay system with SWIPT is studied.The system model is composed of a source node,a relay node,a destination node,and an eavesdropping node,which are equipped with a single antenna.The relay uses full-duplex mode and employs amplify and forward method to forward signals.The energy forwarding signals comes from the energy collected from the radio frequency signals.The destination node also adopts full-duplex mode and sends artificial noise to interfere with the eavesdropping node while receiving information.The main contents are as follows:1.The optimization of secrecy rate in a full-duplex relay system with power splitting SWIPT is studied.The relay node has no fixed energy supply and uses the power splitting method to obtain the energy required for forwarding the signals from the received radio frequency signals.The sources of energy include the signals sent by the source node,the artificial noise sent by the destination node,and self-interference produced by the relay itself.According to whether eavesdropping channel state information is known,the power splitting factor,the allocation factor of signal and artificial noise power are optimized to maximize the secrecy rate of system or channel capacity of legal channel.The simulation results show that optimizing the power splitting factor,the allocation factor of signal and artificial noise power can improve the secrecy rate.2.The optimization of secrecy rate in a full-duplex relay channel with time switching SWIPT is studied.The relay employs the time switching SWIPT method to collect energy from the transmitted signal by the source node for forwarding signals.When the eavesdropping channel state information is known or unknown,the time scaling factor of energy harvesting,the allocation factor between signal and artificial noise power are optimized in order to maximize the secrecy rate of the system or channel capacity of the legal channel.The simulation results show the optimization of the time scaling factor of energy harvesting,the allocation factor between signal and artificial noise power can improve the performance of system.