To determine the performance of a wireless system, channel characterization must be carried out. In fact, in a wireless system, the propagation of an electromagnetic wave in space is of particular importance. For this reason, it is necessary to study the correctness of this channel before starting to work on it and implementing it in a communication system. It is therefore essential to have knowledge of the mechanisms involved in the propagation channel and of its interactions with the environment in order to be able to predict the chances and conditions for establishing a radio link between a transmitter and a receiver. In this work, we propose some strategies to model the transmission channel in the THz band. Indeed, before we can evaluate a transition system over wireless system, we have to model the propagation channel. First, we present the main tools allowing the modelling of the channel in the THz frequency range, which is considered a key new technology to meet the growing demand for higher speed wireless communications, as well as its impact on radio systems. In this paper, we propose a channel model for a wireless system working in the THz band. Besides, we propose some strategies to model the entire system as well as the propagation channel. We also simulate the proposed channel model. The simulation results show that the proposed system can be considered as an example for evaluating the performance of a communication chain based on a wireless system in the THz bands.