A method for transmitting, by a user equipment, UE, uplink data during a random access procedure in a wireless communication, the method comprising: entering a radio resource control, RRC, IDLE state; receiving (S910, S1010, S1210), from a base station, BS, system information including (i) a threshold for early data transmission, EDT, (ii) information informing the UE that the EDT is allowed and (iii) information on at least one random access preamble identifier, RAPID, for the EDT; determining (S920, S1220) that a condition for initiating the EDT is satisfied, based on the system information, by comparing the threshold for the EDT with a size of the uplink data for transmission, wherein the size of the uplink data for transmission is lower than the threshold for the EDT; selecting a RAPID among the at least one RAPID for the EDT, based on initiating the EDT; transmitting, to the BS, a random access preamble with the selected RAPID for the EDT; receiving, from the BS, a random access response message including uplink grant and the RAPID for the EDT; in response to the random access response message, transmitting (S930, S1050, S1230), to the BS, a first RRC message including the uplink data based on the uplink grant during the random access procedure; in response to the first RRC message, receiving, from the BS, a second RRC message indicating acknowledgment of the data, or a third RRC message indicating non-acknowledgment of the data; based on receiving the second RRC message, considering that the transmitted data are acknowledged, and entering the RRC_IDLE state, and based on receiving the third RRC message, considering that the transmitted data are unacknowledged, and entering the RRC_IDLE state. entering a radio resource control, RRC, IDLE state; receiving (S910, S1010, S1210), from a base station, BS, system information including (i) a threshold for early data transmission, EDT, (ii) information informing the UE that the EDT is allowed and (iii) information on at least one random access preamble identifier, RAPID, for the EDT; determining (S920, S1220) that a condition for initiating the EDT is satisfied, based on the system information, by comparing the threshold for the EDT with a size of the uplink data for transmission, wherein the size of the uplink data for transmission is lower than the threshold for the EDT; selecting a RAPID among the at least one RAPID for the EDT, based on initiating the EDT; transmitting, to the BS, a random access preamble with the selected RAPID for the EDT; receiving, from the BS, a random access response message including uplink grant and the RAPID for the EDT; in response to the random access response message, transmitting (S930, S1050, S1230), to the BS, a first RRC message including the uplink data based on the uplink grant during the random access procedure; in response to the first RRC message, receiving, from the BS, a second RRC message indicating acknowledgment of the data, or a third RRC message indicating non-acknowledgment of the data; based on receiving the second RRC message, considering that the transmitted data are acknowledged, and entering the RRC_IDLE state, and based on receiving the third RRC message, considering that the transmitted data are unacknowledged, and entering the RRC_IDLE state.