Power Control Scheme of Reconfigurable Intelligent Surface-Assisted Wireless Communication System Based on Millimeter-Wave Radar

To address the problem of excessive communication system overhead caused by high path loss, low scattering, and frequent switching of high-band communication in complex dynamic wireless environments, a reconfigurable intelligent surface (RIS)-assisted wireless communication system power control scheme based on frequency-modulated continuous-wave millimeter-wave radar (FMCW) is proposed. This paper proposes a power optimization scheme that senses dynamic users and characterizes dynamic environments.The FMCW radar is used to perceive the user and obtains dynamic position information about the user. To maximize the expectation of the signal-to-noise ratio (SNR) of the communication, the upper bound of the system interruption probability is obtained by analysing the effect of the user's location on the system reliability. Moreover, considering the influence of the multipath effect on the system gain, a geometric channel model is established to better reflect the dynamic environment under the multipath effect. Subsequently, while conforming to the constraints of the communication system, the power optimization method based on the binary search algorithm was adopted. Finally, the influence of the FMCW radar perception error on the power control results was analysed, and the error value of the power required for transmission by the base station was 0.4-0.5 dB within the error range. The simulation and analysis results show that the power required for base station transmission obtained using the proposed scheme is approximately 4 dB, which can effectively reduce the power required for system base station transmission.