Research On Physical Layer Security Technology Based On OFDM Simultaneous Wireless Information And Power Transfer

With the continuous development of wireless communication technology,communication devices play an increasingly important role in life,and mobile devices are more widely appearing in life.While wireless communication brings convenience to society,many problems have followed.Mainly because the demand for resources is increasing and the security requirements for information are increasing.Therefore,in the context of limited resources,seeking an effective improvement of resource utilization and information security technology has become an important goal of communication technology development.As a product of the combination of infinite information transmission technology and energy harvesting technology,simultaneous wireless information and power transfer technology collects signals from radio frequency signals through specific technologies,which can carry information and collect energy,effectively improving energy utilization.The emergence of technology has brought tremendous changes and turnarounds to the development of wireless communication technology,and it can largely solve energy-constrained problems and extend the life of mobile devices.However,as the Internet continues to penetrate into every aspect of life,the information security of users is always at risk,and information security has become one of the main problems of wireless communication.In the traditional communication system,the information transmission rate is improved by avoiding signal interference in the system,and the appropriate interference signal is designed to confuse the eavesdropper on the eavesdropping end by the physical layer security method,thereby reducing the signal-to-noise ratio of the eavesdropper and ensuring legality.Improve the information security performance of the system in the case of user signal to noise ratio.Therefore,in the context of wireless communication of wireless information and energy coordinated transmission,this paper combines physical layer security for research and design.main tasks as follows:1.In view of the possibility that the energy receiver may eavesdrop on information,we propose a wireless information and energy cooperative secure transmission method based on Power Splitting(PS)in OFDM system.The energy receiver uses a portion of the received power for energy harvesting on all subcarriers,and another portion for information decoding and information eavesdropping.In order to ensure the secure transmission of the information at the transmitting end,the jammer uses one of the antennas to receive the information of the transmitting end of the information for energy collection,and uses the collected energy to transmit an interference signal on the other antenna to confuse the information receiving of the eavesdropper.By jointly optimizing the power allocation of the information receiving end and the energy receiving end,the information transmission rate of the information receiving end is maximized under the condition that the energy collected by the energy receiving end reaches the minimum requirement.2.Orthogonal Frequency Division Multiplexing(OFDM)technology can dynamically adjust subcarriers and flexibly allocate power on subcarriers.We propose a wireless information and energy cooperative security based on OFDM subcarrier allocation in combination with OFDM technology.Transmission method.The energy receiver uses a part of the subcarriers for energy collection,and another part of the subcarriers is used for information decoding and information eavesdropping.The jammer performs energy harvesting on all subcarriers and then uses the collected energy to transmit the interfering signal to confuse the energy receiver's information reception.We study how the method optimizes the subcarrier and power,and the information transmission rate of the largest information receiving end under the condition of ensuring the minimum energy collection of the energy receiver.