An Overview of Physical Layer Security for IRS-Assisted Downlink Multi-User Massive MIMO Systems

As a research hot-spot, intelligent reflecting surface (IRS) aided downlink multi-user Massive Multiple-input and Multiple output (MIMO) is one of the most important tech-nologies for the 6th Generation (6G) wireless communications. It significantly improves the spectral efficiency and coverage of wireless communication systems. However, the passive eavesdrop-ping threat becomes much more serious and can not be negligible. In this paper, focusing on the multi-IRS aided downlink multi-user Massive MIMO, an overview for the corresponding physical layer security (PLS) methods is presented, and some potential and valuable future research works on PLS for IRS-assisted downlink Massive MIMO are discussed.