Distributed Multi-RIS-assisted GSM-MIMO Systems with Norm-Based RIS Selection Algorithm

Reconfigurable intelligent surface (RIS)-assisted generalized spatial modulation (GSM) systems have recently been regarded as prospective candidates for the upcoming 6G wireless networks. This is primarily because GSM scheme utilizes the indices of the active antennas to convey extra spatial symbols, and RIS can intelligently adjust the wireless propagation environment, leading to a significant improvement in both network coverage and energy efficiency. This paper explores the potential of integrating multiple distributed RISs into GSM scheme and proposes a norm-based RIS selection algorithm to aid the transmission between the transmitter and receiver by selecting a number of RISs with the largest channel norm values. Simulation results demonstrate that the proposed multi-RIS-assisted GSM system with norm-based RIS selection algorithm exhibits superior bit error rate (BER) performance compared to conventional GSM system and multi-RIS-assisted GSM system without RIS selection. Moreover, the proposed system achieves higher power efficiency compared to multi-RIS-assisted GSM system without the selection strategy.