Method and apparatus for mobility management, session management, or connection management of user equipment in mobile communication system
The present disclosure relates to a 5G or pre-5G communication system for supporting a higher data transmission rate than a 4G communication system such as LTE. A method for mobility/session/connection management by user equipment (UE) in a mobile communication system, according to an embodiment of the present disclosure, comprise the steps of: when receiving a paging from an access and mobility management function (AMF) while registered with the AMF, transmitting a service request message to the AMF; receiving a service accept from the AMF; and transmitting a protocol data unit (PDU) session modification request message to the AMF, wherein a first timer may start when transmitting the service request message, and a second timer may start when transmitting the PDU session modification request message.
1 . A method performed by a user equipment (UE) in a communication system, the method comprising:
in case that the UE receives a paging from an access and mobility management function (AMF) in a state of being registered in the AMF, transmitting, to the AMF, a service request message;
transmitting, to the AMF, a protocol data unit (PDU) session modification request message; and
in case that a second timer expires before a first timer is stopped, retransmitting, to the AMF, the PDU session modification request message,
wherein the first timer starts in case that the UE transmits the service request message, and the second timer starts in case that the UE transmits the PDU session modification request message.
2 . The method of claim 1 , further comprising, as a response to the PDU session modification request message, receiving, from the AMF, a downlink (DL) non-access stratum (NAS) transport message indicating that the PDU session modification request message is not forwarded to a session management function (SMF).
3 . The method of claim 2 , further comprising retransmitting the PDU session modification request message in case that the second timer expires after the DL NAS transport message is received.
4 . A user equipment (UE) in a communication system comprising:
a transceiver; and
at least one processor coupled with the transceiver and configured to:
in case that the UE receives a paging from an access and mobility management function (AMF) in a state of being registered in the AMF, transmit, to the AMF, a service request message,
transmit, to the AMF, a protocol data unit (PDU) session modification request message, and
in case that a second timer expires before a first timer is stopped, retransmit, to the AMF, the PDU session modification request message,
wherein the first timer starts in case that the UE transmits the service request message, and the second timer starts in case that the UE transmits the PDU session modification request message.
5 . The UE of claim 4 , wherein the at least one processor is further configured to: as a response to the PDU session modification request message, receive, from the AMF, a downlink (DL) non-access stratum (NAS) transport message indicating that the PDU session modification request message is not forwarded to a session management function (SMF).
6 . The UE of claim 5 , wherein the at least one processor is further configured to retransmit the PDU session modification request message in case that the second timer expires after the DL NAS transport message is received.
7 . A method performed by an access and mobility management function (AMF) in a communication system, the method comprising:
transmitting, to a user equipment (UE), a paging;
as a response to the paging, receiving, from the UE, a service request message;
receiving, from the UE, a protocol data unit (PDU) session modification request message; and
in case that a second timer expires before a first timer is stopped, receiving, from the UE, a retransmitted PDU session modification request message,
wherein the first timer starts in case that the UE transmits the service request message to the AMF, and the second timer starts in case that the UE transmits the PDU session modification request message to the AMF.
8 . The method of claim 7 , further comprising transmitting, to the UE, a downlink (DL) non-access stratum (NAS) transport message indicating that the PDU session modification request message is not forwarded to a session management function (SMF).
9 . The method of claim 8 , further comprising receiving, from the UE, the PDU session modification request message in case that the second timer expires after the DL NAS transport message is transmitted.
10 . An access and mobility management function (AMF) in a communication system, the AMF comprising:
a transceiver; and
at least one processor coupled with the transceiver and configured to:
transmit, to a user equipment (UE), a paging,
as a response to the paging, receive, from the UE, a service request message,
receive, from the UE, a protocol data unit (PDU) session modification request message, and
in case that a second timer expires before a first timer is stopped, receive, from the UE, a retransmitted PDU session modification request message,
wherein the first timer starts in case that the UE transmits the service request message to the AMF, and the second timer starts in case that the UE transmits the PDU session modification request message to the AMF.
11 . The AMF of claim 10 , wherein the at least one processor is configured to transmit, to the UE, a downlink (DL) non-access stratum (NAS) transport message indicating that the PDU session modification request message is not forwarded to a session management function (SMF).
12 . The AMF of claim 11 , wherein the at least one processor is configured to receive, from the UE, the PDU session modification request message in case that the second timer expires after the DL NAS transport message is transmitted.