Sources of confusion noise in the infrared wavelength range
  In this paper we use the model of extragalactic background light to
investigate the factors that have influence on the confusion noise. It was
shown that (1) Large-Scale Structure of the Universe is an important factor;
(2) gravitational lensing does not have a significant effect on the confusion
noise; (3) lower redshift limit of objects that contribute to the confusion
noise does not depend on the wavelength and is about $z_{min}\sim 0.5-0.6$,
while upper redshift limit gradually changes from $\sim4$ to $\sim3$ with the
increase of wavelength from 70$\mu m$ up to 2000$\mu m$; (4) at rather short
wavelengths ($\simeq70\mu m$) galaxies with luminosities in the range
$10^7L_\odot$ -- $10^9L_\odot$ give the most contribution to the confusion
noise, while at larger wavelengths (650-2000$\mu m$) their luminosities are
greater than $L\geq10^{10}L_\odot$; (5) contribution from objects with
different color characteristics is considered; (6) the variability of the
extragalactic background on the timescale from 1 day to 1 year is noticeable at
short wavelengths (70--350$\mu m$) and manifests at fluxes ${}^<_\sim$ 1~mJy.
