Known for many years but unexploited in the field of communications, ultra wideband systems (UWB) can be a solution to the saturation of the frequency bands. The advantage of such systems is that they are inexpensive in energy because of the limitations imposed by the standard. Our work is to design a high data rate IR-UWB system, through the use of modulation M-OAM (Orthogonal Amplitude Modulation), and the study of the system performances by adding the effect of the propagation channels dedicated to the UWB. The channel modeling is an important step in the implementation of any system, especially for those in development, as is the case of UWB systems. Although this model is one of the key elements of the overall chain system, it must take into account the distance between the two antennas, multipath and signal type. In this paper, we discover the existing models suitable for UWB channels and their implementation on our M-OAM system. The introduction of real channels in our chain of transmission reduces the quality of our system. Therefore, a RAKE receiver is proposed as a solution to improve performance.