How to Extend 3-D GBSM to Integrated Sensing and Communication Channel With Sharing Feature?

Integrated Sensing and Communication (ISAC) is a promising technology in 6G systems. The existing 3D Geometry-Based Stochastic Model (GBSM), standardized for 5G systems, addresses solely communication channel and lacks consideration of the integration with sensing channel. Therefore, this letter extends 3D GBSM to support ISAC research, with a particular focus on capturing the sharing feature of both channels, including shared scatterers, clusters, paths, and similar propagation parameters, which have been experimentally verified in our previous work. The proposed approach can be summarized as follows: Firstly, we propose an ISAC channel model that combines shared and non-shared clusters, where the former co-exist or disappear for communication and sensing. Secondly, to characterize the target, the sensing channel is modeled as a cascade of Tx-target link, target-Rx link, and target scattering response. A novel parameter S is introduced for the extraction of shared targets/scatterers and clusters. Finally, an ISAC channel implementation framework is proposed, allowing flexible configuration of the sharing feature and the joint generation of communication and sensing channels. The proposed ISAC channel model can be well-compatible with the 3GPP standards and offers promising support for ISAC technology evaluation.