  Integrated sensing and communication (ISAC) is expected to play a crucial
role in the sixth-generation (6G) mobile communication systems, offering
potential applications in the scenarios of intelligent transportation, smart
factories, etc. The performance of radar sensing in ISAC systems is closely
related to the characteristics of radar sensing and communication channels.
Therefore, ISAC channel modeling serves as a fundamental cornerstone for
evaluating and optimizing ISAC systems. This article provides a comprehensive
survey on the ISAC channel modeling methods. Furthermore, the methods of target
radar cross section (RCS) modeling and clutter RCS modeling are summarized.
Finally, we discuss the future research trends related to ISAC channel modeling
in various scenarios.
