The need for high data rates of several Gbit/s in 5G and beyond wireless networks will require capacities of 100 Gbit/s in the backhaul and fronthaul links. 300 GHz wireless links are promising candidates to provide these links. The paper describes the ongoing activities in the EU-Japan project ThoR towards suitable propagation and channel models applicable for the simulation and planning of such links. The corresponding modelling activities are based on ray tracing models, which are enhanced by taking into account atmospheric propagation effects, measured characteristic of building materials and the effect of wind to the poles, where the antennas are mounted. First results applied to realistic simulation scenarios are presented.