Energy Efficiency Optimization Of Downlink Multi-user EH Distributed Antenna System

Distributed antenna system is a research hotspot of wireless mobile communication.Compared with the traditional centralized antenna system,the distributed antenna system is easy to deploy.The low power consumption and small size of the remote antenna unit shorten the distance between the user and the antenna,greatly increase the system capacity,and improve the coverage at the edge of the cell.At the same time,as people's demand for high-speed,high-quality and multi-service services increases day by day,the energy consumption of the communication system also increases sharply.This promotes the development of green communication technologies that aim to reduce system energy consumption and improve system energy efficiency,such as energy harvesting(EH)technology,simultaneous wireless and power transfer(SWIPT)technology,etc.Based on this,this paper studies the energy efficiency optimization of the downlink in a multi-user EH distributed antenna system using SWIPT,as follows:Firstly,a multi-user EH distributed antenna system model was established in the downlink communication link,in which the remote antenna unit could collect energy,and the receiver used SWIPT technology.Considering the user information rate constraint and the minimum collected energy constraint,a target optimization problem based on maximizing energy efficiency was formed.In order to solve the optimization problem,a series of problem transformations and decompositions were made to the problem,thereby completing the mathematical analysis.A multiuser EH distributed antenna system energy efficiency optimization algorithm was obtained.And the optimized power split ratio and energy distribution factor were obtained.In order to verify this model,this paper used Matlab to simulate and verify the system model and obtain good results.Secondly,on the basis of the above,considered the inter-user interference in the system,including the interference of the same remote antenna unit and its access users to the target user and the interference of other remote antenna unit access users to the target user,and the EH distribution to the downlink multi-user.The energy efficiency optimization problem of the antenna system has been further studied.The zero-forcing(ZF)precoding technology was used to eliminate the interference between users.The energy efficiency optimization problem was transformed into a joint optimization problem of user power allocation and power split ratio.And the mathematical analysis was completed and the optimization problem was solved.The simulation results showed that this method can effectively eliminate the interference between users and improve the energy efficiency of the system.