User device, control device, and communication control method

At least one control device in a core network for implementing error handling, the at least one control device in the core network comprising:

• a transceiver unit that:
• receives, from a user device, a first Protocol Data Unit (PDU) session modification request message used to initiate a PDU session modification procedure,
• transmits, in the PDU session modification procedure, an No. 46 5G Session Management (5GSM) cause value to the user device in order to indicate that the user device is prohibited from transmitting a second PDU session modification request message for a PDU session for a Local Area Data Network (LADN), and
• receives, from the user device, a registration request message used to initiate a registration procedure for requesting new LADN information, wherein:
• the PDU session for the LADN is established in a PDU session establishment procedure using an LADN Data Network Name (DNN),
• the LADN DNN is provided in the PDU session establishment procedure, the No. 46 5GSM cause value indicates an update to LADN information stored at the user device,
• the registration request message includes an LADN indication information element and is transmitted based on reception of the No. 46 5GSM cause value, and
• the transmission of the second PDU session modification request message for the PDU session for the LADN is prohibited until the registration procedure for requesting the new LADN information is completed.

A communication control method performed by a user device for implementing error handling, the communication control method comprising:

• establishing, with at least one control device in a core network, a Protocol Data Unit (PDU) session for a Local Area Data Network (LADN) in a PDU session establishment procedure that uses an LADN Data Network Name (DNN);
• transmitting, to the at least one control device in the core network, a first PDU session modification request message used to initiate a PDU session modification procedure,
• receiving, in the PDU session modification procedure, an No. 46 5G Session Management (5GSM) cause value from the at least one control device in the core network;
• and
• prohibiting, based on reception of the No. 46 5GSM cause value, transmission of a second PDU session modification request message for the PDU session,
• wherein:
• the LADN DNN is provided by the user device in the PDU session establishment procedure,
• the No. 46 5GSM cause value indicates an update to LADN information stored at the user device,
• the user device requests, based on reception of the No. 46 5GSM cause value, new LADN information by including an LADN indication information element in a registration request message used to initiate a registration procedure for requesting the new LADN information, and
• the transmission of the second PDU session modification request message for the PDU session for the LADN is prohibited until the registration procedure for requesting the new LADN information is completed.