Abstract: Systems and techniques for handling a protocol data unit (PDU) session by a wireless device implementing an access stratum (AS) layer and a non-access stratum (NAS) layer in a wireless communication system. An example technique includes determining, by the AS layer of the wireless device, whether a user plane for the PDU session is activated or released; transferring, by the AS layer and to the NAS layer of the wireless device based on a determination that the user plane for the PDU session is activated, first information indicating that the user plane for the PDU session is activated; and transferring, by the AS layer and to the NAS layer of the wireless device based on a determination that the user plane for the PDU session is released, second information indicating that the user plane for the PDU session is released.

Abstract: One disclosure of the present specification provides a method for transmitting, by user equipment, a PDU session establishment request. The method comprises the steps of: receiving a session management message based on an SSC mode from an SMF through an AMF in a state in which a back-off timer associated with a DNN-based congestion control is in operation, wherein the session management message is associated with a DNN to which the DNN based congestion control is applied; and transmitting a PDU session establishment request to the AMF for establishment of a new PDU session associated with the DNN on the basis of the session management message, wherein the PDU session establishment request includes information for preventing rejection of the PDU session establishment request, and the information for preventing the rejection may be used to make the AMF ignore the DNN-based congestion control and transmit the PDU session establishment request to the SMF associated with the new PDU session.

Abstract: An aspect of the disclosure relates to a method for supporting a local access data network (LADN) service by an access and mobility management function (AMF) in a wireless communication system, and the method may comprise the steps of: providing LADN information for the LADN service to a terminal, wherein the LADN information includes LADN service area information and LADN data network name (DNN) information; acquiring location information of the terminal; when establishment of a packet data unit (PDU) session for providing the LADN service is determined on the basis of the location information of the terminal, transmitting to the terminal a preset message including a request for the establishment of the PDU session; and receiving, from the terminal, a request message for initiating the establishment of the PDU session.

Abstract: Disclosed in the present specification is a method by which a user equipment (UE) performs access control. The method comprises the steps of: allowing a non-access-stratum (NAS) layer of the UE to transfer information on an important service and a NAS signaling request to a radio resource control (RRC) layer, when the important service is required even if access to a cell is currently interrupted or a back-off timer is operated; and allowing the RRC layer to skip or override an inspection for access control on the basis of the information on the important service, wherein, the information on the important service can be set in advance.

Abstract: Disclosed herein is a network-initiated deregistration method by an access and mobility management function (AMF) in a wireless communication system, including: receiving a first message having a removal reason configured to subscription withdrawn from a unified data management (UDM); and transmitting a deregistration request message for requesting the deregistration to a user equipment (UE), in which the deregistration is enabled to be performed for all accesses in which the UE is registered when the removal cause received from the UDM through the first message indicates the subscription withdrawn of the UE.

Abstract: One disclosure of the present specification provides a method for supporting service continuity after a terminal performs a handover. The method may comprise: a step of transmitting, when re-assigned from a source user plane (UP) functional node to a target UP functional node in accordance with performing a handover to a target base station, a PDU session creation request message to create a new PDU session with the target UP functional node; a step of receiving a PDU session creation response message including a newly allocated second IP address; a step of transmitting a tunneling request message including information on the newly allocated second IP address and information on a service flow requiring service continuity; and a step of encapsulating a packet, which has been generated with an existing first IP address by an upper layer of the terminal, with a new second IP address by a lower layer of the terminal and transmitting the encapsulated packet to the tunneling entity.

Abstract: One disclosure of the present specification provides a method for a terminal creating a session, the terminal supporting next-generation mobile communication. The method may comprise the steps of: determining that a session must be newly created if the creation of a session is not included in a process of attaching to a core network of a next-generation mobile communication; on the basis of service type information, determining that the session being newly created needs to be always-on, or in other words, always-connected; and transmitting, to a control plane (CP) function node for managing the session, a connectivity request message including information indicating that the session that needs to be always-on, or in other words, always-connected, has been requested.

Abstract: According to one aspect of the present invention, a method for supporting a user equipment (UE) handover of a target (T)-access and mobility management function (AMF) in a wireless communication system may comprise the steps of: receiving a UE context creation request message from a source (S)-AMF, wherein the UE context creation request message includes packet data unit (PDU) session identifiers (ID) as a handover target and single (S)-network slice selection assistance information (NSSAI) corresponding to each PDU session ID; determining whether the corresponding S-NSSAI is valid in the T-AMF; and sending, to a session management function (SMF), a PDU session update session management (SM) context request message only for a PDU session ID that corresponds to the S-NSSAI determined to be valid according to the determination result, out of the PDU session IDs.

Abstract: The one disclosure of the present specification proposes a method for managing session. The method may be performed by a session management function, SMF, node and comprise: generating a packet data unit, PDU, session for a user equipment, UE; receiving, from an access and mobility management function, AMF, node, information about the UE; and determining, based on the information, whether to transmit an indication for notifying a user plane function, UPF, node to discard a downlink data for the PDU session of the UE. The determination may be dependent on whether the PDU session corresponds to a first service provided to the UE.

Abstract: In one embodiment of the present invention, a method for enabling a UDM (Unified Data Management) to perform a registration related procedure of an AMF (Access and Mobility Management Function) in a wireless communication system comprises the steps of: receiving, by the UDM, a message related to serving AMF registration of a UE, which includes access type information and ID (Identity) information, from a first AMF; transmitting, by the UDM, a deregistration related message to a second AMF when the second AMF exists, wherein the second AMF is registered as a serving AMF of the UE and related to the access type information.

Abstract: A core network to which a cell of a base station can be connected may not be specified to be one. For example, a cell may be connected to an EPC, may be connected to a next-generation core network, or may be connected to both an EPC and a next-generation core network. The base station may transmit core network information relating to a core network to which the cell is connected, on the cell. A user equipment may determine whether to camp on the cell on the basis of the core network information.

Abstract: A disclosure in the present specification provides a method for user equipment initiating a service request procedure. The method includes a step of the UE receiving a paging message. The UE may be registered to both of a 3rd generation partnership project (3GPP) access and a non-3GPP access within the same PLMN. The paging message may include access type information that is used so as to indicate the non-3GPP access. The method may include a step of initiating a UE triggered service request procedure. The UE triggered service request procedure may be initiated by transmitting a service request message including a list of permitted protocol data unit (PDU) sessions. The service request message may include an empty list of the permitted PDU sessions if there is no PDU sessions that can be reactivated in the 3GPP access.

Abstract: In one embodiment of the present invention, a method for enabling a UDM (Unified Data Management) to perform a registration related procedure of an AMF (Access and Mobility Management Function) in a wireless communication system comprises the steps of: receiving, by the UDM, a message related to serving AMF registration of a UE, which includes access type information and ID (Identity) information, from a first AMF; transmitting, by the UDM, a deregistration related message to a second AMF when the second AMF exists, wherein the second AMF is registered as a serving AMF of the UE and related to the access type information.

Abstract: In an aspect of the present invention, a method for a user equipment to update a policy in a wireless communication system may include transmitting a first registration request message to an access and mobility management function (AMF), wherein the first registration request message includes requested network slice selection assistance information (NSSAI) including single (S)-NSSAI corresponding to a network slice with which the user equipment wants to register; receiving a first registration accept message as a response to the first registration request message from the AMF, wherein the first registration accept message includes an allowed NSSAI including at least one S-NSSAI allowed by the AMF; and requesting the update of a network slice selection policy (NSSP) associated with new S-NSSAI from the AMF when the new S-NSSAI not included in the requested NSSAI is included in the allowed NSSAI and the NSSP associated with the new S-NSSAI is not present.

Abstract: An embodiment of the present invention relates to a method for an access and mobility management function (AMF) transmitting and receiving a signal related to a handover from 5GS to an evolved packet system (EPS) of a user equipment (UE) in a wireless communication system the method comprising a step in which the AMF receives a handover required message from a next-generation radio access network (NG-RAN); a step in which the AMF requests a session management (SM) context to a packet data network gateway+session management function (PGW+SMF); a step of receiving an SM context from the PGW+SMF; and a step in which the AMF transmits a handover command to the NG-RAN, wherein the SM context request is for a PDU session associated with 3GPP access among a plurality of protocol data unit (PDU) sessions.

Abstract: A method performed by a terminal operating in a wireless communication system. Based on that the terminal is located in a non-allowed area, and based on the terminal having a pending uplink signaling to inform a change in a Packet Switch (PS) data off status of the terminal, the terminal transmits a service request message to a network node. The service request message includes service type information that is related to the change in the PS data off status of the terminal. The terminal then receives, from the network node, a response message to the service request message.

Abstract: In an aspect of the present invention, a method for a user equipment (UE) to perform reflective quality of service (QoS) in a wireless communication system may include the steps of receiving a downlink packet from a network, wherein the downlink packet is a packet to which the application of the reflective QoS is indicated; deriving a QoS rule based on the downlink packet; applying a QoS marking of the downlink packet to an uplink packet using the QoS rule and transmitting the uplink packet to the network; and restarting a timer associated with the QoS rule when the downlink packet is received before the timer expires.

Abstract: Systems and techniques for handling a protocol data unit (PDU) session by a wireless device implementing an access stratum (AS) layer and a non-access stratum (NAS) layer in a wireless communication system. An example technique includes determining, by the AS layer of the wireless device, whether a user plane for the PDU session is activated or released; transferring, by the AS layer and to the NAS layer of the wireless device based on a determination that the user plane for the PDU session is activated, first information indicating that the user plane for the PDU session is activated; and transferring, by the AS layer and to the NAS layer of the wireless device based on a determination that the user plane for the PDU session is released, second information indicating that the user plane for the PDU session is released.

Abstract: Disclosed herein is a network-initiated deregistration method by an access and mobility management function (AMF) in a wireless communication system, including: receiving a first message having a removal reason configured to subscription withdrawn from a unified data management (UDM); and transmitting a deregistration request message for requesting the deregistration to a user equipment (UE), in which the deregistration is enabled to be performed for all accesses in which the UE is registered when the removal cause received from the UDM through the first message indicates the subscription withdrawn of the UE.

Abstract: Provided is a tracking area assignment method by an access and mobility management function (AMF) in a wireless communication system. The method may include receiving, from a session management function (SMF), service and session continuity (SSC) mode indication information for a protocol data unit (PDU) session generated for a user equipment (UE), obtaining serving area information for a serving area of a serving user plane function (UPF) associated with the PDU session, determining the assignment of a new tracking area to the UE is necessary based on a tracking area pre-assigned to the UE and the serving area, and performing tracking area update for the assignment of the new tracking area to the UE if it is determined that the assignment of the new tracking area is necessary.