  Reconfigurable intelligent surfaces (RISs) have emerged as a promising
technology in wireless communications. Simultaneously transmitting and
reflecting RIS (STAR-RISs) in particular have garnered significant attention
due to their dual capabilities of simultaneous transmission and reflection,
underscoring their potential applications in critical scenarios within the
forthcoming sixth-generation (6G) technology landscape. Moreover, full-duplex
(FD) systems have emerged as a breakthrough research direction in wireless
transmission technology due to their high spectral efficiency. This paper
explores the application potential of STAR-RIS in FD systems for future
wireless communications, presenting an innovative technology that provides
robust self-interference cancellation (SIC) capabilities for FD systems. We
utilize the refraction functionality of STAR-RIS enhances the transmission
capacity of FD systems, while its reflection functionality is used to eliminate
self interference within the FD system. We delve into the applications of two
different types of STAR-RIS in FD systems and compare their performance through
simulations. Furthermore, we discuss the performance differences of STAR-RIS
empowered FD systems under various configurations in a case study, and
demonstrate the superiority of the proposed deep learning-based optimization
algorithm. Finally, we discuss possible future research directions for STAR-RIS
empowered FD systems.
