Single-RF MIMO: From Spatial Modulation to Metasurface-Based Modulation

In multiple-input multiple-output (MIMO) systems, multiple radio frequency (RF) chains are usually required to simultaneously transmit data streams. As a special MIMO technology, spatial modulation (SM) activates one antenna by requiring RF chain and exploits the index of active for information transfer at each time slot. Recently, reconfigurable metasurfaces have emerged as promising technology that is able reconfigure wireless propagation environment altering amplitude and/or phase incident signal. this article, we aim implementation single-RF shifting focus from SM metasurface-based modulation. Specifically, principles first presented. After reviewing evolution SM, elaborate on idea metasurface-aided discuss some implementations it in line with notable variants SM. A comparison between antenna-based meta-surface-based made highlight advantages using metasurfaces. We finally investigate research challenges opportunities context