  The coming Planck and Herschel missions will survey the sky at unprecedented
angular scales and sensitivities. Simulations are needed for better
interpretating the results of the surveys and for testing new methods of, e.g.,
source extraction and component separation. We present new simulations of the
infrared and submillimeter cosmic background, including the correlation between
infrared galaxies. The simulations were used to quantify the source-detection
thresholds for Herschel/SPIRE and Planck/HFI, as well as to study the
detectability of the cosmic infrared background correlated fluctuations.
  The simulations are based on an empirical model of IR galaxy evolution. For
the correlations, we only included the linear clustering, assuming that
infrared galaxies are biased tracers of the dark-matter fluctuation density
field. We used the simulations with different bias parameters to predict the
confusion noise for Herschel/SPIRE and Planck/HFI and the completeness levels.
We also discuss the detectability of the linear clustering in Planck/HFI power
spectra, including the foreground and backgrounds components.
  Simulated maps and catalogs are publicly available online at
http://www.ias.u-psud.fr/irgalaxies/simulations.php
