Reconfigurable Intelligent Surface-Based Multidimensional Index Modulation Multiple Access

In this article, a reconfigurable intelligent surface-based multidimensional index modulation multiple access (RIS-MD-IMMA) scheme is proposed to fully utilize the potential of index modulation (IM) for multiple access (MA) in an RIS environment. In the proposed scheme, the information of different users is transmitted using symbols with different index entities, and the receiver detects the respective index information independently. Compared with the traditional RIS-assisted nonorthogonal MA (RIS-NOMA) scheme, the proposed scheme mitigates intracluster interference among users and eliminates superposition coding and successive interference cancellation (SIC) operations needed in NOMA. To reduce the required power consumption and computational complexity of the receiver detection, a low-complexity (LC) detection algorithm for RIS-MD-IMMA is proposed. The simulation analysis results show that RIS-MD-IMMA performs better in terms of both the number of serviceable users and bit error rate (BER) performance compared with RIS-NOMA.