The Role of Massive MIMO and Intelligent Reflecting Surface in 5G/6G Networks

The fifth generation (5G) mobile communication systems are being widely deployed and tested worldwide, and the key techniques are gradually maturing in 2021. Considering the general needs in the future of the explosive growth of data, researchers around the world are beginning to study the next-generation system, i.e., the sixth generation (6G) communication systems, which will be deployed in the future network of 2030. This review begins with the historical development of communication systems, and elaborates on the current and future innovations of communication technologies. The key technology of 5G, massive multiple-input multiple-output (MIMO), is introduced, especially into the advantages and challenges to the deployment of 5G. Meanwhile, the potential key technology in 6G, intelligent reflecting surface (IRS) is also presented, the concept of IRS and the advantage in the aspect of energy efficiency is given in the paper.