Space-Time Block Coded Reconfigurable Intelligent Surfaces-Based Generalized Spatial Modulation

Abstract

In this paper, we propose a novel scheme named RIS-ASTBC-GSM by introducing both Alamouti space time block code (ASTBC) and generalized spatial modulation (GSM) into reconfigurable intelligent surface (RIS), which could effectively enhance the diversity and spectral efficiency in RIS-assisted wireless communication system. In the proposed scheme, the RIS could transmit extra information bits through generalized spatial modulation. Specifically, we divide the RIS into several groups, and different groups corresponds to different group selection patterns. Additionally, we establish a relational mapping between group selection patterns and information bits. Then, the modulated symbols are transmitted by utilizing the determined group selection pattern. Moreover, a mathematical framework is derived for RIS-ASTBC-GSM to characterize the theoretical average bit error probability (ABEP) of the system by employing the moment generating function (MGF). Finally, the superiority of the RIS-ASTBC-GSM is confirmed through simulation results, which outperforms the performance of RIS-assisted Alamouti's scheme at the same bit per channel use (bpcu).