  The recently published first measurement of charged hadron multiplicity
density at mid-rapidity $dN_{ch}/d\eta=1584 \pm 4 ({\rm stat.}) \pm 76 ({\rm
sys.})$ in central $Pb+Pb$ collisions at $\sqrt{s} = 2.76$ TeV by the ALICE
Experiment at LHC is in good agreement with the HIJING2.0 prediction within the
experimental errors and theoretical uncertainties. The new data point is used
to carry out a combined fit together with the RHIC data to reduce the
uncertainty in the gluon shadowing parameter $s_{g}$ which controls the overall
magnitude of gluon shadowing at small fractional momentum $x$ in HIJING2.0
model. Predictions on the centrality dependence of charged hadron multiplicity
density at mid-rapidity with reduced uncertainty are given for $Pb+Pb$
collisions at $\sqrt{s}=2.76$ and 5.5 TeV. The centrality dependence is
surprisingly independent of the colliding energy as compared to RHIC energy for
most of centralities starting at $N_{\rm part}=50$ (100) at $\sqrt{s}=2.76$ (7)
TeV. However, it becomes stronger in peripheral collisions at higher colliding
energies.
