User equipment, and an apparatus and method used in user equipment are perform a predetermined data transmission in which the user equipment transmits uplink user data when the user equipment is in an RRC inactive state. The user equipment, apparatus and method transmit a random access preamble for the predetermined data transmission to a base station during a random access procedure, and transmit an MSG 3 message together with uplink user data to the base station during the random access procedure. A base station performs a predetermined data transmission in which a user equipment transmits uplink user data when the user equipment is in an RRC inactive state, includes a receiver receiving a random access preamble for the predetermined data transmission during a random access procedure from the user equipment, and receives an MSG 3 message together with uplink user data from the user equipment during the random access procedure.