  Soft processes in pp and AA interactions are considered in the framework of
phenomenological model with color strings formation and fusion. Elementary
parton collisions are realized in the model as the interaction of two colour
dipoles from projectile and target nucleons. Modeling of the exclusive
distributions of parton momentum fractions and transverse coordinates is
performed. The interaction of colour strings in transverse plane is carried out
in the framework of local string fusion model with the introduction of the
lattice in the impact parameter plane and taking into account the finite
rapidity length of strings. The parameters were fixed with experimental data on
pp total inelastic cross section and charged multiplicity. The model was used
for the calculation of long-range correlations between the multiplicities (n)
and the mean transverse momenta (pt) of charged particles. The dependence of
n-n, pt-n, pt-pt correlations on the width and position of the backward and
forward rapidity windows was studied. Note that the model enables to describe
the AA interactions without referring to the Glauber picture based on the
concept of elementary nucleon-nucleon collisions. In this connection the
charged multiplicity, the mean numbers of participant nucleons and binary
collisions and their variances in the case of PbPb collisions were calculated
and compared with the predictions of alternative models and the experimental
data. The influence of different ways of centrality determination on the
multiplicity fluctuations and long-range correlations was also discussed.
