  In heavy-ion ({\it A-A}) collisions, the correlations among the particles
produced across wide range in rapidity, probe the early stages of the reaction.
The analyses of forward-backward multiplicity correlations in these collisions
are complicated by several effects, which are absent or minimized in
hadron-hadron collisions. This includes effects, such as the centrality
selection in the {\it A-A} collisions, which interfere with the measurement of
the dynamical correlations. A method, which takes into account the fluctuations
in centrality selection, has been utilized to determine the forward-backward
correlation strength {$b_{\rm corr}$} in {\itA-A} collisions. This method has
been validated by using the HIJING event generator in case of Au-Au collisions
at $\sqrt{s_{NN}}$= 200 GeV and Pb-Pb collisions at $\sqrt{s_{NN}}$= 2.76 TeV.
It is shown that the effect of impact parameter fluctuations is to be
considered properly in order to obtain meaningful results.
