In this paper, we consider a full-duplex (FD) space shift keying (SSK) communication system, where information exchange between two users is assisted only by a reconfigurable intelligent surface (RIS). In particular, the impact of loop interference (LI) between the transmit and receive antennas as well as residual self-interference (SI) from the RIS is considered. Based on the maximum likelihood detector, we derive the conditional pairwise error probability and the numerical integration expression for the unconditional pairwise error probability (UPEP). Since it is difficult to find a closed-form solution, we perform accurate estimation by the Gauss-Chebyshev quadrature (GCQ) method. To gain more useful insights, we derive an expression for UPEP in the high signal-to-noise ratio region and further give the average bit error probability (ABEP) expression. Monte Carlo simulations were performed to validate the derived results. It is found that SI and LI have severe impacts on system performance. Fortunately, these two disturbances can be well counteracted by increasing the number of RIS units.

翻译：本文研究了一种全双工（FD）空间移位键控（SSK）通信系统，其中两个用户之间的信息交换仅由可重构智能表面（RIS）辅助。具体而言，考虑了发射天线与接收天线之间的环路干扰（LI）以及RIS产生的残余自干扰（SI）的影响。基于最大似然检测器，推导了条件成对错误概率，以及无条件成对错误概率（UPEP）的数值积分表达式。由于难以获得闭合解，采用高斯-切比雪夫求积（GCQ）方法进行精确估计。为进一步获取有价值的见解，推导了高信噪比区域下的UPEP表达式，并进一步给出了平均误比特概率（ABEP）表达式。通过蒙特卡洛仿真验证了推导结果。研究发现，SI和LI对系统性能有严重影响。所幸的是，通过增加RIS单元数量，可以有效抵消这两种干扰。