Space Shift Keying With Reconfigurable Intelligent Surfaces: Phase Configuration Designs and Performance Analysis

Reconfigurable intelligent surface (RIS)-assisted transmission and space shift keying (SSK) appear as promising candidates for future energy-efficient wireless systems. In this article, two RIS-based SSK schemes are proposed to efficiently improve the error throughput performance of conventional systems, respectively. The first one, termed RIS-SSK with passive beamforming (RIS-SSK-PB), employs an RIS targets maximization minimum squared Euclidean distance between any decision points. second Alamouti space-time block coding (RIS-SSK-ASTBC), ASTBC enables transmit its own Alamouti-coded information while reflecting incident signals destination. A low-complexity beamformer efficient maximum-likelihood (ML) detector designed RIS-SSK-PB RIS-SSK-ASTBC, Approximate expressions average bit probabilities source and/or derived in closed-form assuming ML detection. Extensive computer simulations conducted verify analysis. Results show that significantly outperforms existing RIS-free schemes, RIS-SSK-ASTBC highly reliable improvement.