This paper describes the parameters of a typical impulse response generated by the ray tracer simulator developed by the SIC laboratory of POITIERS. This simulator is based on a physical model, a 3D description of the environment and ray tracing algorithm to research for the multipath components (MPC). UWB channel consists of several MPCs arriving to the receiver in clusters. In fact, an algorithm of identification of clusters using a physical approach was implemented. Then a very particular attention was given to the evolution of the delay spread and the distribution of the received power as a function of the distance. The paper identifies also the distributions of interarrival times of clusters and MPCs within clusters.