Power absorption rate of lower hybrid wave by ions has been estimated by the convection, conduction loss and the charge exchange loss both in the main plasma region and in the boundary region of a circular tokamak. It is shown that when an effective ion heating is performed in the main plasma region the rf power is not dissipated in the boundary region through the parametric decay instabilities. The rate of the dissipated rf power in the boundary region saturate at relatively low power level and does not give the fatal effect on the ion heating in the main region if we select an appropriate plasma parameters.