Recent Activities on Advanced MIMO Technology of 6G Radio Technology Project under XGMF

This paper introduces the activities of the Advanced MIMO Working Group (A-MIMO WG) of the 6G Radio Technology Project under the XG Mobile Promotion Forum (XGMF), established in Japan. This working group aims to build consensus on the evolution of MIMO technology, particularly toward 6G, through extensive discussions and the exchange of research findings among various institutions, including telecom operators, network (NW) and user equipment device (UE) vendors, and academia organizations. A key point highlighted in the discussions is that the demanding requirements for communication quality, strict antenna installation regulations, and the narrow, congested, and complex regional characteristics of Japan have led to a strong focus on distributed massive MIMO technology, resulting in extensive research and development efforts. Including these points, the WG published a white paper compiling their activities, and some of them are introduced here.