A Standardization Framework for Channel Modeling in RIS-Assisted Integrated Sensing and Communication Systems

Reconfigurable intelligent surfaces (RISs) are novel devices that can manipulate the wireless propagation environment, which can bring significant impact to the sensing and communications in sixth generation (6G). The 3rd Generation Partner Project (3GPP) Technical Specification Group Service and System Aspects Working Group 1 (SA1) has outlined some scenarios and requirements for integrated sensing and communication (ISAC). Following the outcomes of SA1, the channel model for ISAC is under intense discussion in Radio Access Network Working Group 1 (RAN1). Given the advantages of RIS in both communications and sensing functionalities, it can be envisaged that RIS-assisted ISAC will likely play an important role in the future generation wireless systems. To fully reap the benefits of RIS-assisted ISAC, a comprehensive ISAC channel model encompassing RIS is essential. This article provides a comprehensive perspective on the channel model for RIS-assisted ISAC, including general procedures, challenges, and solutions within large-scale parameters (LSPs) and small-scale parameters (SSPs) of channel coefficient generation, while discussing insights regarding future research avenues for the interplay between RIS and ISAC.