Spin transport in the two-dimensional electron gas with strong spin-orbit interaction is examined by using a simple phenomenological simulation. The large spin-orbit interaction and the randomized electron trajectory due to the impurity scattering make the nonlocal voltage of a spin field effect transistor undetectable in the diffusive regime. However, the spin-precessional phase accumulates coherently in the ballistic regime and the nonlocal voltage is given by a function of spin-orbit interaction parameter. If the distance between injector and detector is comparable to the mean free path, a sinusoidal oscillation of nonlocal voltage is restored even for a wide channel. (C) 2010 Elsevier B.V. All rights reserved.