Research On The Power Allocation Of Physical Layer Security Transmission Of Energy Sharing EH-DAS

Distributed Antennas System(DAS)is the key technology of 5G and an important direction of wireless communication development.The ultra-high-speed development of wireless communication makes energy consumption increase day by day.How to use energy harvesting(EH)technology to design new green energy supply methods has become a research hotspot.With the advent of the era of big data,the high-level encryption technology of information is facing huge challenges,and it is imminent how to effectively use physical security technology to achieve safe and reliable data transmission.Therefore,it is particularly important to solve the problem of energy shortage and communication security in DAS.Aiming at these two problems,this paper proposes an EH-DAS physical layer security transmission model based on energy sharing.Based on this model,the secrecy energy efficience of energy sharing EH-DAS physical layer security transmission is studied.According to whether the energy collected by the RAU is preferentially shared or not,two different ways of sharing the collected energy are proposed.The specific summary is as follows:(1)An EH-DAS physical layer security transmission model with excess downlink energy sharing in a single cell is established.Considering the worst case of information security transmission,that is,eavesdropping users use all the signals they receive for information decoding,and combined with the constraints of energy sharing and information security transmission,an optimization problem with the goal of maximizing secrecy energy efficience is formed.Because the secrecy energy efficience of the system will vary with the transmit power of the Remote Antenna Unit(RAU),the optimization problem is further decomposed into the optimal power allocation without considering the harvested energy constraints and the optimal power allocation considering the harvested energy constraints.Two sub-problems,the final RAU optimal transmit power allocation strategy is obtained by solving the sub-problems respectively.MATLAB simulation results show that the introduction of artificial noise(AN)can improve the secrecy energy efficience of EH-DAS,which can effectively reduce the loss of traditional energy while ensuring the security of system communication.(2)In order to fully share the energy collected by the RAUs and be suitable for scenarios with uneven energy distribution,a single-cell downlink energy priority sharing EH-DAS physical layer security transmission model is established,considering the priority transmission of the energy collected by the RAUs.The energy sharing pool is given to the energy sharing pool and stored,and then the energy sharing pool reasonably schedules the stored energy according to the instructions of the baseband processing unit and allocates it to the RAUs in need for information transmission.In order to solve the optimization problem,the Dinkelbach method and the Lagrange multiplier method are used to solve the problem,and the optimal power distribution strategy is obtained by combining with the water injection algorithm.The MATLAB simulation results confirm that the introduction of AN in the transmitted signal can improve the secrecy energy efficience of the system and the system has better stability.