Reconfigurable intelligent surfaces (RIS) as an effective technique for intelligently manipulating channel paths through reflection to serve desired users. Full-duplex (FD) systems, enabling simultaneous transmission and reception from a base station (BS), offer the theoretical advantage of doubled spectrum efficiency. However, the presence of strong self-interference (SI) in FD systems significantly degrades performance, which can be mitigated by leveraging the capabilities of RIS. In this work, we consider joint BS and RIS beamforming for maximizing the downlink (DL) transmission rate while guaranteeing uplink (UL) rate requirement. We propose an FD-RIS beamforming (FRIS) scheme by adopting penalty convex-concave programming. Simulation results demonstrate the UL/DL rate improvements achieved by considering various levels of imperfect CSI. The proposed FRIS scheme validates their effectiveness across different RIS deployments and RIS/BS configurations. FRIS has achieved the highest rate compared to the other approximation method, conventional beamforming techniques, HD systems, and deployment without RIS.

翻译：可重构智能表面（RIS）是一种通过反射智能操控信道路径以服务目标用户的有效技术。全双工（FD）系统支持基站（BS）同时进行收发，理论上具有频谱效率翻倍的优势。然而，FD系统中存在的强自干扰（SI）会显著降低性能，而利用RIS的能力可缓解这一问题。本文考虑联合基站与RIS波束成形，在保障上行（UL）速率要求的同时最大化下行（DL）传输速率。我们提出了一种FD-RIS波束成形（FRIS）方案，采用惩罚凸-凹规划方法。仿真结果表明，在考虑不同程度的不完美信道状态信息（CSI）时，该方案能实现上行/下行速率提升。所提出的FRIS方案在不同RIS部署及RIS/基站配置下的有效性得到了验证。与其他近似方法、传统波束成形技术、半双工（HD）系统及无RIS部署相比，FRIS实现了最高速率。