A user equipment in a mobile communication system including a base station and the user equipment, the user equipment comprising: selection means configured to receive a plurality of signaling values and a plurality of maximum transmission power values corresponding to the plurality of signaling values respectively from the base station, to select one signaling value of the plurality of signaling values, and to select a maximum transmission power value corresponding to the selected signaling value; and control means configured to perform cell selection or cell reselection by determining whether at least Equation 1, Srxlev > 0, is satisfied in a cell to be determined in the cell selection or cell reselection, Srxlev denoting a cell selection reception level value, wherein Srxlev in Equation 1 is expressed by Equation 2, Srxlev = Q rxlevmeas - (Q rxlevmin + Q rxlevminoffset) - Pcompensation - Qoffset temp, Q rxlevmeas in Equation 2 denotes a reception level value measured for the cell to be determined, Q rxlevmin in Equation 2 denotes a minimum reception level required for the cell, Q rxlevminoffset in Equation 2 denotes an offset, and Qoffset temp in Equation 2 denotes a parameter used when a timer expires, Pcompensation in Equation 2 is expressed by Equation 3, max (P EMAX1 - P PowerClass, 0) - (min (P EMAX2, P PowerClass) - min (P EMAX1, P PowerClass)), and P EMAX1 in Equation 3 denotes a predetermined maximum transmission power value, P EMAX2 in Equation 3 denotes the maximum transmission power value selected by the selection means, and P PowerClass in Equation 3 denotes a maximum output power value based on a power class of the user equipment. selection means configured to receive a plurality of signaling values and a plurality of maximum transmission power values corresponding to the plurality of signaling values respectively from the base station, to select one signaling value of the plurality of signaling values, and to select a maximum transmission power value corresponding to the selected signaling value; and control means configured to perform cell selection or cell reselection by determining whether at least Equation 1, Srxlev > 0, is satisfied in a cell to be determined in the cell selection or cell reselection, Srxlev denoting a cell selection reception level value, wherein Srxlev in Equation 1 is expressed by Equation 2, Srxlev = Q rxlevmeas - (Q rxlevmin + Q rxlevminoffset) - Pcompensation - Qoffset temp, Q rxlevmeas in Equation 2 denotes a reception level value measured for the cell to be determined, Q rxlevmin in Equation 2 denotes a minimum reception level required for the cell, Q rxlevminoffset in Equation 2 denotes an offset, and Qoffset temp in Equation 2 denotes a parameter used when a timer expires, Pcompensation in Equation 2 is expressed by Equation 3, max (P EMAX1 - P PowerClass, 0) - (min (P EMAX2, P PowerClass) - min (P EMAX1, P PowerClass)), and P EMAX1 in Equation 3 denotes a predetermined maximum transmission power value, P EMAX2 in Equation 3 denotes the maximum transmission power value selected by the selection means, and P PowerClass in Equation 3 denotes a maximum output power value based on a power class of the user equipment.