Beyond massive MIMO: reconfigurable intelligent surface-assisted wireless communications

Abstract

In this chapter, we have provided a brief overview of the concept of RISs, illustrated their potential for future wireless networks over simple propagation scenarios, covered the recent contributions in this frontier, and outlined potential use -cases of RISs in future wireless networks. As discussed earlier, the radical concept of communications through RISs may be a potential remedy for saturated wireless networks under the existing plethora of modern PHY and medium access control layer solutions. The fundamental idea behind the concept of RIS-assisted wireless networks is moving the functions that are usually implemented at the transmitter or receiver ends of communication systems to the environment. Within this perspective, the integration of RISs with emerging technologies, such as massive MIMO, mmWave communications, VLC, THz communication, IoT, and UAV networks, appears as a promising and unexplored research direction. The development of empirical RIS architectures as well as RIS-assisted channel models also stands out as an interesting future research direction.