Research on Signal Processing Technology of Intelligent Reflection-Assisted Millimeter Wave Large-Scale MIMO System

Millimeter-wave (mmWave) communication, characterized by its abundant spectrum resources and high data transmission capabilities, is a key technology for 6G. However, its propagation characteristics, such as high path loss and susceptibility to blockage, present significant challenges. Integrating large-scale multiple-input multiple-output (MIMO) technology with intelligent reflecting surfaces (IRS) addresses these challenges by dynamically adjusting the wireless propagation environment, thereby enhancing signal coverage and mitigating interference. This research examines a large-scale mmWave MIMO system enhanced by an Intelligent Reflecting Surface (IRS), the system consists of a base station (BS) with a large antenna array, multiple user equipment (UE) devices, and an intelligent reflecting surface (IRS). Both the BS and the UEs are equipped with mmWave transceivers, while the IRS is placed between the BS and UEs to assist with signal transmission. In this mmWave MIMO system enhanced by the IRS, the objective is to optimize the beamforming by simultaneously adjusting the precoding matrix at the BS and the reflection coefficient matrix at the IRS, with the aim of maximizing the system throughput or reducing the bit error rate (BER). Considering the sparsity of mmWave channel and the reflection characteristics of IRS, an iterative algorithm based on alternate optimization is adopted. Through theoretical analysis and experimental verification, this research puts forward innovative signal processing strategy, which significantly improves the throughput of the system, reduces BER, and enhances the communication quality and the stability and robustness of the link in complex environment. The simulation outcomes indicate a roughly 30% increase in system throughput, a notable reduction in link outage probability, and a steady Bit Error Rate (BER) remaining below 10^-5. These results validate the proposed method's effectiveness in enhancing both the overall communication performance and the reliability of the system.