RIS-Enabled Multi-Domain Joint Rectangular Differential Index Modulation Using RF Mirrors

Reconfigurable intelligent surface (RIS) is a promising technology for future 6G communications. However, channel state information (CSI) for RIS-enabled communication systems is difficult to obtain. This letter proposes a novel multi-domain joint rectangular differential index modulation (MJRDIM) scheme, which is enabled through RIS and radio frequency (RF) mirror technologies to achieve noncoherent index modulation (IM) across space, media, and reflection domains. The proposed scheme designs a space-media precoding (SMP) codebook to jointly control the mirror activation patterns (MAPs) of RF mirrors and antenna activation for more efficient space-media domain mapping. The SMP codebook is further optimized by maximizing the minimum Euclidean distance to improve the bit error rate (BER) performance of MJRDIM. Theoretical analysis and simulation results demonstrate that the proposed MJRDIM scheme achieves significant advantages in BER performance and reduced decoding complexity compared to other schemes.