... (1) Perfect instantaneous CSI: Most of the existing works have considered transmission design based on the assumption that the instantaneous CSI is perfectly available. Based on this assumption, the performance gains provided by introducing an RIS in various wireless applications have been investigated, such as mmWave/terahertz systems [84], [89], [142]- [145], multicell systems [101], [146], [147], physical layer security systems [83], [87], [88], [97], [98], [148], [149], simultaneous wireless information and power transfer (SWIPT) [99], [108], [113], [150]- [154], mobile edge computing networks [74], [111], [155]- [160], multicast networks [96], [161], cognitive radio networks [138], [162], [163], non-orthogonal multiple access [90], [92], [110], [112], [164]- [169], two-way communications [85], [100], and full-duplex (FD) communication [170]. In these works, the AO method was adopted to alternately optimize the beamforming vectors at the BS and the phase shifts at the RIS, and the phase shift optimization problem was addressed using the algorithms summarized in Subsection III-A. ...