  In this paper, the question of observability of a heavy charged Higgs in the
mass range 400 GeV < mH < 1000 GeV, is addressed. The production process is set
to pp -> H+ -> tb at 14 TeV LHC. The analysis benefits from top tagging
technique which is based on finding a fat jet as a result of the boosted top
quark decay in signal events. A detailed hadron level analysis is performed and
selection efficiencies are presented with different charged Higgs mass
hypotheses. Finally running toy experiments and using pseudo-data, a fit over
signal plus background distributions is performed to assess possibility of
reconstructing the charged Higgs peak and its invariant mass measurement. It is
shown that the charged Higgs mass can well be reconstructed in the mass range
500 GeV to 1 TeV, with a signal significance which depends on tanbeta.
Eventually 5sigma discovery and 95% C.L. exclusion contours are also provided.
