  We propose a phenomenological model of dephasing in mesoscopic transport,
based on the introduction of random phase fluctuations in the computation of
the scattering matrix of the system. A Monte Carlo averaging procedure allows
us to extract electrical and microscopic device properties. We show that, in
this picture, scattering matrix properties enforced by current conservation and
time reversal invariance still hold. In order to assess the validity of the
proposed approach, we present simulations of conductance and magnetoconductance
of Aharonov-Bohm rings that reproduce the behavior observed in experiments, in
particular as far as aspects related to decoherence are concerned.
