US Patent 11178705 Terminal device, MME, and communication method

To provide a communication procedure such as an attach procedure suitable for a CIoT terminal. A method includes: a step of receiving an ATTACH ACCEPT message from a core network; a step of transmitting user data by using a radio bearer for transmitting and/or receiving a control message in a case that the ATTACH ACCEPT message does not include first identification information; and a step of establishing a Packet Data Network (PDN) connection and/or a radio bearer for user data transmission and/or reception and transmitting user data by using the Packet Data Network (PDN) connection and/or the radio bearer for user data transmission and/or reception, in a case that the ATTACH ACCEPT message includes the first identification information.