Transforming ISAC With STAR-RIS: Design, Challenges, and Opportunities

Integrating sensing and communication functionalities are essential for realizing the vision of ubiquitous connectivity and supporting emerging applications in future wireless networks. Integrated sensing and communication (ISAC) offers an efficient approach for sharing resources, such as spectrum and hardware, however, traditional wireless systems face significant challenges in complex real-world environments. Reconfigurable intelligent surfaces (RISs) have emerged as a promising solution, enabling intelligent manipulation of wireless signals to enhance both sensing and communication in an energy-efficient manner. However, conventional RISs, which rely solely on reflection, are limited to half-space coverage. To overcome this limitation, simultaneously transmitting and reflecting RIS (STAR-RIS) has been introduced, expanding network coverage and providing a higher degree of freedom for signal manipulation. This article explores integrating STAR-RIS into ISAC systems, highlighting their potential to revolutionize wireless networks. We examine various deployment scenarios for STAR-RIS-enabled ISAC, discuss their advantages and challenges, and present a case study showcasing performance gains. Furthermore, we identify crucial research directions to address challenges in modeling, deployment, and application, paving the way for the future of intelligent and connected wireless systems.