  Numerical simulations offer the unique possibility to forecast the results of
surveys and targeted observations that will be performed with next generation
instruments like the Square Kilometre Array. In this paper, we investigate for
the first time how future radio surveys in polarization will be affected by
confusion noise. To do this, we produce 1.4 GHz simulated full-Stokes images of
the extra-galactic sky by modelling various discrete radio sources populations.
The results of our modelling are compared to data in the literature to check
the reliability of our procedure. We also estimate the number of polarized
sources detectable by future surveys. Finally, from the simulated images we
evaluate the confusion limits in I, Q, and U Stokes parameters, giving
analytical formulas of their behaviour as a function of the angular resolution.
