MIMO systems have raised a lot of interests in the recent years especially in the radar community. For MIMO systems with widely spaced antennas for example it has been shown that channel matrices are decorrelated from one another. The view diversity of an illuminated target is then increased. And as a consequence the detection probability of statistical MIMO systems increases thanks to this gain diversity. In this paper we present the finite scattering point model introduced by Haimovich and demonstrate the equivalence between the MIMO scattering problem using the finite scattering point model and the random walk problem. Studying the convergence of the central limit theorem applied to this problem, we demonstrate that it is possible to estimate the scattering points density for a low number of scatterers in the resolution cell. Finally we show that statistical MIMO system suppresses the interferences between scatterers and maximises the target response.