Reconfigurable Intelligent metaSurface () is a cross-border innovation of electromagnetic metamaterials and modern wireless communication technology. The technology uses programmable new subwavelength two-dimensional metamaterials to control electromagnetic waves actively and intelligently through digital coding, and realizes controllable reflection and transmission of 5G signals. It can be used for in scenarios such as outdoor coverage blind spots and indoor coverage by outdoor base stations, providing a low-cost, low-power-consumption, and scientific and feasible innovation path for the in-depth coverage of 5G networks and future network evolution.