Research of Transparent RIS Technology toward 5G evolution & 6G

Abstract

The introduction of the 5th-generation mobile communications system (5G) commercial services has begun throughout the world, and at present, research toward the further development of 5G (5G evolution) and the development of 6G as the next-generation mobile communications system is being actively pursued. In this article, we describe the intelligent radio environment (IRE), an important concept in "New Radio Network Topology" now under discussion on the road to 5G evolution & 6G. We also describe NTT DOCOMO's initiatives toward the reconfigurable intelligent surface (RIS), an important component of IRE, and metamaterial/metasurface technologies as elemental technologies of RIS.