A method of calculating a specified value when entering a second radio resource (RR) mode from a first RR mode is disclosed. More specifically, the method includes calculating a new specified value to be used in the second RR mode using a filter, an iteration index, and a last specified value calculated in the first RR mode if the calculation of the specified value is performed in the first RR mode, and calculating a new specified value to be used in the second RR mode by restarting the filter if the calculation of the specified value is not performed in the first RR mode.