Guest editorial: Channel measurements and models for 6G

In the early stage of 6G research, carrying out research on channel measurements and models is one of the fundamental and prerequisite works, as well as full of the challenges. Driven by the demand for multiple frequency bands, versatile scenarios, and various new technologies in the future, 6G channels are expanding in multiple dimensions such as the space-time-frequency domains. Those all make 6G channel measurement and modeling research face a series of new challenges, e.g., non-stationarity in multiple dimensions, the obvious increase in modeling complexity, and changes in theoretical premises and assumptions. It is therefore clear that more efforts are needed to understand propagation characteristics, especially in the new scenes and applications, and to develop a new paradigm for 6G channel modeling.