RIS Grouping Based Index Modulation for 6G Telecommunications

In this letter, a novel reconfigurable intelligent surface (RIS) grouping based index modulation (RGB-IM) is proposed to enhance spectral efficiency and improve bit error rate (BER). The idea is to divide an RIS into several number of group-surfaces (GR). Furthermore, the incoming data bits are modulated to spatial symbol, which represents the index of one of the available GR that will be activated at a particular time. In addition, the impact of RIS imperfect channel estimation is investigated in this letter. Both spectral efficiency and BER of the proposed system are simulated and validated with theoretical result. The computer simulation results indicate that the RGB-IM outperform a relay-assisted spatial modulation (SM).