Research On Intelligent Reflecting Surface Beamforming Algorithms And Realization Of Its Control System

Fifth generation mobile communication systems(5G)have largely met the growing user demand for communication rates,reliability,low latency and connectivity,but still suffer from serious problems of high hardware costs and energy consumption.In addition,current communication technologies are unable to adapt to the changing wireless propagation environment,making it difficult to guarantee communication quality in harsh wireless environments where signal blockage or fading is severe.Recently,the Intelligent Reflective Surface(IRS)technology has been proposed as a solution that has attracted much attention in the industry as it improves the spectral efficiency and energy efficiency of wireless communication systems and reduces the cost and complexity of communication by influencing the wireless propagation environment to achieve an intelligent radio environment.Based on IRS technology,the problem of optimizing the energy efficiency of user reception for IRS-assisted multiple-input single-output(MISO)systems is investigated,and a joint beam assignment scheme is designed.In addition,an FPGA-based IRS control system is designed and implemented.Details of the research and contributions are as follows.(1)In order to make the beam assignment optimization results closer to the actual engineering implementation,an IRS beam assignment optimization scheme based on the actual phase shift model is investigated.The optimization problem of jointly optimizing the active beam assignment of the base station and the reflected beam assignment of the IRS is established with the objective of maximizing the user reception energy efficiency while considering the transmit power of the base station.For the original non-convex problem,an alternating optimization iteration algorithm based on the block-coordinate descent method and the Dinkelbach method is investigated.The simulation results show that the studied optimization algorithm can effectively improve the user received energy efficiency in the MISO system.(2)IRS control system circuit and software program are designed.The overall design framework of the IRS control system is introduced in detail.The system uses FPGA as the control device,and is designed with serial communication circuit,serial-to-parallel circuit,drive circuit,LED dot matrix and other modules.Finally,the circuit is designed and processed by PCB,and the hardware design and implementation of the control system are completed.(3)Write Verilog program to realize the functional design of IRS control system.After the IRS encoded data is sent to the FPGA for processing through the serial port,the DC bias signal is output to the PIN diodes of each reflection unit of the IRS,and the bias state is adjusted in real time to complete the reflection beamforming.Finally,the actual test and verification of the control system is carried out,which meets the requirements of the control system development.