Abstract:Intelligent Connected Vehicles (ICVs) rely on high-speed data transmission for efficient and safety-critical services. However, the scarcity of wireless resources limits the capabilities of ICVs. Semantic Communication (SemCom) systems can alleviate this issue by extracting and transmitting task-relevant information, termed semantic information, instead of the entire raw data. Despite this, we reveal that residual redundancy persists within SemCom systems, where not all instances under the same semantic category are equally critical for downstream tasks. To tackle this issue, we introduce Instance Communication (InsCom), which elevates communication from the semantic level to the instance level for ICVs. Specifically, InsCom uses a scene graph generation model to identify all image instances and analyze their inter-relationships, thus distinguishing between semantically identical instances. Additionally, it applies user-configurable, task-critical criteria based on subject semantics and relation-object pairs to filter recognized instances. Consequently, by transmitting only task-critical instances, InsCom significantly reduces data redundancy, substantially enhancing transmission efficiency within limited wireless resources. Evaluations across various datasets and wireless channel conditions show that InsCom achieves a data volume reduction of over 7.82 times and a quality improvement ranging from 1.75 to 14.03 dB compared to the state-of-the-art SemCom systems.