Reconfigurable intelligent surface assisted multi-user MIMO uplink transmission method

Abstract

The invention provides a reconfigurable intelligent surface assisted multi-user MIMO uplink transmission method. According to the transmission method, a signal sent by a user side is reflected to a base station through an RIS, and the RIS can change the phase of the signal incident on the RIS. Aiming at a bottleneck problem of channel information acquisition of an RIS-assisted multi-user MIMO transmission system, only partial channel state information is utilized, including instantaneous channel state information from the RIS to a base station channel and statistical channel state informationfrom a user to the RIS channel; through an alternate optimization method, a deterministic equivalence principle, a block coordinate descent method, an MM method and the like, a sending covariance matrix and an RIS phase shift matrix of a user are jointly designed to maximize the global energy efficiency of the system or traverse the spectral efficiency; when the channel state information is changed, the user side dynamically implements transmission power distribution with maximum energy or spectral efficiency, and the RIS dynamically adjusts the phase shift matrix. According to the invention,the implementation complexity is low, and the performance of multi-user MIMO uplink transmission can be effectively improved.

Description

technical field [0001] The invention belongs to the field of communication, and in particular relates to a multi-user MIMO uplink transmission method assisted by a reconfigurable smart surface using partial channel state information. Background technique [0002] Reconfigurable Intelligent Surface (RIS) is a programmable surface composed of electromagnetic materials and controlled by integrated electronic devices, which is a two-dimensional application of metamaterials. The RIS is equipped with several reflection units, which can change the phase of the signal incident on it without changing the amplitude of the incident signal. [0003] In a RIS-assisted wireless communication system, RIS can build an intelligent radio environment, that is, a controllable, reconfigurable propagation environment. Furthermore, the wireless communication system can alleviate the influence caused by multipath propagation and Doppler spread of the wireless channel, thereby improving the system ...

AI Technical Summary

Problems solved by technology

Traditional wireless communication transmission optimization problems are often based on instantaneous channel state information, but for RIS-assisted wireless communication systems, it is difficult to obtain instantaneous channel state information, and the use of instantaneous channel state information for transmission will increase the power consumption of RIS

Images