RIS-Assisted Full-Duplex Space Shift Keying: System Scheme and Performance Analysis

To unlock the full potential of next-generation networks, we investigate reconfigurable intelligent surfaces (RIS) assisted wireless communication systems, in which two full-duplex (FD) users simultaneously communicate via the space shift keying (SSK) technique. According to the channel state information, we investigate two schemes, i.e., intelligent phase-shift and blind phase-shift RIS-FD-SSK schemes. Then, we analyze the average bit error probability (ABEP) of the RIS-FD-SSK scheme employing a maximum likelihood detector. For the intelligent phase-shift scheme, the closed-form ABEP expressions are derived, and the exact approximating ABEP is obtained via the Gaussian-Chebyshev quadrature method. To gain more valuable insights, asymptotic ABEP is also provided in this paper. For the blind phase-shift scheme, we derive exact and upper bound ABEP expressions and asymptotic ABEP expression. Furthermore, the analytical derivation results are verified by Monte Carlo simulations. Results demonstrate that the proposed RIS-FD-SSK system outperforms the conventional half-duplex (HD) scheme in terms of ABEP as the capability of the loop-interference cancellation technique increases. Additionally, as the data rate enhances, the RIS-FD-SSK scheme can achieve better ABEP performance than the RIS-HD-SSK scheme.