  Based on the vision on the 6G wireless communication network, i.e., global
coverage, all spectrums and all applications, we comprehensively survey 6G
related wireless channel measurements, channel characteristics, and channel
models for all frequency bands and all scenarios. Millimeter wave (mmWave),
terahertz (THz), optical band, satellite, unmanned aerial vehicle (UAV),
maritime, underwater acoustic, high-speed train (HST), vehicle-to-vehicle
(V2V), massive/ ultra-massive multiple-input multiple-output (MIMO), orbital
angular momentum (OAM), and industry Internet of things (IoT) communication
channels were particularly investigated. The related 6G channel measurement and
modeling results were also given. Finally, future research challenges on 6G
channel measurements and modeling were pointed out.

Signal Processing