A user equipment in a radio communication system including the user equipment and a base station, including: an uplink transmission power information calculation unit configured to calculate uplink transmission power information of a serving cell using a parameter that may be changed dynamically; and a signal transmission unit configured to include, in control information in which the uplink transmission power information is set, identification information for identifying a parameter used for calculation of the uplink transmission power information, and to transmit the control information in which the identification information is included to the base station.