The development of wireless technologies led to the birth of numerical dosimetry for non- ionizing radiation. In another hand, studies of the wireless communication channel improve the knowledge of the electromagnetic environment. This paper studies the impact of wireless channel modelling, especially the cluster concept, on the exposure of a body model. An analytical expression of Whole Body Specific Absorption Rate SARW B mean and its standard deviation are developed and evaluated with different conditions of exposure in order to do a statistical study of SARWB. The point is to identify the parameters of the Wireless Channel which led to significant SARW B variations.