Method for managing PLMN attempt counters based on tracking area updating in user equipment supporting MINT-EPS under disaster conditions

1 . An operation method of user equipment (UE), comprising:

determining whether a minimization of service interruption (MINT)-evolved packet system (EPS) is supported;

maintaining a list of public land mobile network (PLMN)-specific attempt counters for a determined PLMN with disaster condition if the UE supports the MINT-EPS;

transmitting a tracking area update request message;

receiving a tracking area update accept message;

resetting a PLMN-specific attempt counter of a first PLMN for the determined PLMN with disaster condition, if the tracking area update accept message is received from the first PLMN and if the tracking area update accept message is for a disaster roaming service; and

if the UE has determined the determined PLMN with disaster condition, and if an additional globally unique temporary identifier (GUTI) is included in the tracking area update request message and does not contain a valid GUTI mapped from a 5G-GUTI which was previously assigned, inserting the determined PLMN with disaster condition into the tracking area update request message.

2 . The method of claim 1 , further comprising:

setting an EPS update type in the tracking area update request message to a disaster roaming update, if the tracking area update request message is for the disaster roaming service.

3 . The method of claim 1 , wherein the tracking area update request message includes the determined PLMN with disaster condition.

4 . The method of claim 1 , further comprising:

if the UE has determined the determined PLMN with disaster condition, and if an additional GUTI is not included in the tracking area update request message and an EPS mobility identity does not contain a valid GUTI mapped from a 5G-GUTI which was previously assigned, inserting the determined PLMN with disaster condition into the tracking area update request message.

5 . A user equipment (UE), the UE comprising:

at least one processor; and

at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed by the at least one processor, perform operations comprising:

determining whether a minimization of service interruption (MINT)-evolved packet system (EPS) is supported;

maintaining a list of public land mobile network (PLMN)-specific attempt counters for a determined PLMN with disaster condition if the UE supports the MINT-EPS;

transmitting a tracking area update request message;

receiving a tracking area update accept message;

resetting a PLMN-specific attempt counter of a first PLMN for the determined PLMN with disaster condition, if the tracking area update accept message is received from the first PLMN and if the tracking area update accept message is for a disaster roaming service; and

if the UE has determined the determined PLMN with disaster condition, and if an additional globally unique temporary identifier (GUTI) is included in the tracking area update request message and does not contain a valid GUTI mapped from a 5G-GUTI which was previously assigned, inserting the determined PLMN with disaster condition into the tracking area update request message.

6 . The UE of claim 5 , wherein the operations further comprise:

setting an EPS update type in the tracking area update request message to a disaster roaming update, if the tracking area update request message is for the disaster roaming service.

7 . The UE of claim 5 , wherein the tracking area update request message includes the determined PLMN with disaster condition.

8 . The UE of claim 5 , wherein the operations further comprise:

if the UE has determined the determined PLMN with disaster condition, and if an additional GUTI is not included in the tracking area update request message and an EPS mobility identity does not contain a valid GUTI mapped from a 5G-GUTI which was previously assigned, inserting the determined PLMN with disaster condition into the tracking area update request message.

9 . A semiconductor chipset, comprising:

at least one processor; and

at least one memory capable of storing instructions and being connected electrically to the at least one processor operably,

wherein operations, performed when the instructions are executed by the at least one processor, includes:

determining whether a minimization of service interruption (MINT)-evolved packet system (EPS) is supported;

maintaining a list of public land mobile network (PLMN)-specific attempt counters for a determined PLMN with disaster condition if the UE supports the MINT-EPS;

transmitting a tracking area update request message;

receiving a tracking area update accept message;

resetting a PLMN-specific attempt counter of a first PLMN for the determined PLMN with disaster condition, if the tracking area update accept message is received from the first PLMN and if the tracking area update accept message is for a disaster roaming service; and

if the UE has determined the determined PLMN with disaster condition, and if an additional globally unique temporary identifier (GUTI) is included in the tracking area update request message and does not contain a valid GUTI mapped from a 5G-GUTI which was previously assigned, inserting the determined PLMN with disaster condition into the tracking area update request message.

10 . The semiconductor chipset of claim 9 , wherein the operations further comprise:

setting an EPS update type in the tracking area update request message to a disaster roaming update, if the tracking area update request message is for the disaster roaming service.

11 . The semiconductor chipset of claim 9 , wherein the tracking area update request message includes the determined PLMN with disaster condition.

12 . The semiconductor chipset of claim 9 , wherein the operations further comprise:

if the UE has determined the determined PLMN with disaster condition, and if an additional GUTI is not included in the tracking area update request message and an EPS mobility identity does not contain a valid GUTI mapped from a 5G-GUTI which was previously assigned, inserting the determined PLMN with disaster condition into the tracking area update request message.