Abstract: A disclosure of the present specification provides a method for a wireless communication device to perform communication based on a plurality of SIMs. The method may include the steps of: transmitting a request message to a first network node of a second network, the request message including first information pertaining to the plurality of SIMs; and receiving an acceptance message for the request message from the first network node of the second network.

Abstract: Provided are a method and a device for processing a network slice-specific authentication and authorization (NSSAA) failure caused by a network error or timeout. An access and mobility management function (AMF): starts an NSSAA procedure for an NSSAA function (NSSAAF) and single network slice selection assistance information (S-NSSAI); and restarts the NSSAA procedure after waiting for a certain period, on the basis that the Hypertext Transfer protocol (HTTP) status code “504 Gateway Timeout” is received from the NSSAAF, and/or a response regarding the NSSAA procedure could not be received from the NSSAAF.

Abstract: Provided are a method and device for efficient public land mobile network (PLMN) selection upon authentication failure for each network slice in a roaming network. A user equipment (UE) receives a registration rejection message from an access and mobility management function (AMF) of a first PLMN. The registration rejection message includes rejected network slice selection assistance information (NSSAI) including first single NSSAI (S-NSSAI) and cause value #62 for the rejected NSSAI. The UE: generates second requested NSSAI including second S-NSSAI on the basis that i) the UE does not have allowed NSSAI and configured NSSAI, and ii) default configured NSSAI includes the second S-NSSAI that is not included in the rejected NSSAI and corresponds to a network slice of which the UE requests registration; and transmits a second registration request message including the second requested NSSAI to the AMF of the first PLMN.

Abstract: One disclosure of the present specification provides a communication method, for handling a network error, performed by a terminal. The terminal can receive information relating to a second public land mobile network (PLMN) to which the terminal is subscribed from a base station in a first PLMN. The terminal can be connected to the first PLMN by means of the base station in the first PLMN on the basis of the information relating to the second PLMN. Information notifying of an error which has occurred in the second PLMN can be displayed on a display of the terminal.

Abstract: A disclosure of the present specification provides a method for accessing another Public Land Mobile Network (PLMN) instead of a subscribed third PLMN. According to the method, a terminal may access a second PLMN, which provides a service, instead of a first PLMN that is roaming-agreed with the third PLMN. In addition, according to the method, the terminal may display, on a screen, information indicating that access is made to the second PLMN. The second PLMN may provide only a limited service.

Abstract: One disclosure of the present specification provides a method by which a terminal that joined a first public land mobile network (PLMN) performs a connection. The method may comprise a step for transmitting a first request message to a network node through a base station. The base station may be a base station of a second PLMN that broadcasts system information including information about the first PLMN. The method may comprise a step for receiving, from the network node, a first acceptance message for the first request message. The first acceptance message may include information indicating that there is a service failure in the first PLMN. The method may comprise a step for displaying, on a screen of the terminal, information indicating that the terminal is connected to the second PLMN on the basis of the information.

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: To achieve the aforementioned objective, one disclosure of the present specification may provide a method for transmitting an SM signal to a terminal capable of connecting to a plurality of access networks. The method may comprise the steps of: an AMF node receiving a request for transmission of the SM signal from an SMF node, the request comprising information about an access network to transmit the SM signal; the AMF node determining an access network to transmit the SM signal to the terminal on the basis of information about the access network; and if the terminal is connected to the AMF node via the determined access network, the AMF node transmitting the SM signal to the terminal via the determined access network.

Abstract: Provided in one disclosure in the present specification is a multi-access (MA) protocol data unit (PDU) session method using user equipment (UE). The method can comprise a step of transmitting a first request message for a performance measurement function (PMF) binding request to a PMF layer of a user plane function (UPF) node on the basis of PMF address information about the UPF node included in measurement assistance information (MAI). The PMF binding request can be performed according to quality of service (QoS) flow. The method can comprise a step of receiving a PMF binding response message from the PMF layer of the UPF node. The PMF binding response message can include a reflective QoS indication (RQI).

Abstract: According to one disclosure of the present specification, provided is a method in a network node that manages mobility in a second public land mobile network (PLMN). According to the method, an access request message from a terminal may be received through a base station in the second PLMN. In addition, a response message to an access request of the terminal may be transmitted. The response message may include information indicating rejection to the access request of the terminal, on the basis of the terminal that joined a third PLMN and on the basis of the base station that transmitted system information including information about a first PLMN on behalf of a base station of the first PLMN.

Abstract: A method for transmitting, by user equipment, a PDU session establishment request includes: 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. 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: 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: A disclosure of the present specification provides a method performed by a network node that manages mobility in a first public land mobile network (PLMN). The network node may receive an access request message of a terminal from a base station in the first PLMN. The terminal may be a terminal having joined a second PLMN. On the basis of occurrence of a failure in the second PLMN, the network node may determine whether to allow the terminal to roam to the first PLMN.

Abstract: One disclosure of the present specification provides a method for using a multi-access (MA) protocol data unit (PDU) session of a terminal. The method may comprise the steps of: displaying a configuration screen on whether to use a MA PDU session; displaying information representing the establishment or use of the MA PDU session if the MA PDU session is configured to be usable and if two access networks are both in a usable state; and displaying detailed information on the MA 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: One disclosure of the present specification provides a method for operating in relay user equipment (UE). The method may comprise the steps of: receiving a communication request message directly from a first remote UE; performing a procedure for establishing an access and mobility management function (AMF) entity and a protocol data unit (PDU) session; and storing mapping information between an identifier of a PC5 link with the first remote UE and an identifier of the PDU session on the basis of the PDU session being established for an unstructured PDU session type for unstructured traffic.

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: A disclosure of the present specification provides a method for managing a PDU session performed by an SMF node. The method may comprise the steps of: determining to release an MA PDU session for at least one access of a 3GPP access and a non-3GPP access; and transmitting a message associated with the release of the PDU session to an AMF node.

Abstract: Provided in one disclosure of the present specification is a user equipment (UE) for establishing a Protocol Data Unit (PDU) session. The UE may include: a transmission and reception unit; and a processor for controlling the transmission and reception unit. The processor may perform: a step for assessing whether there is a possibility of the PDU session being handed over to a non-3rd Generation Partnership Project (non-3GPP) access; a step for determining the ID of the PDU session according to the assessment; and a step for transmitting a message including the determined ID of the PDU session.

Abstract: A registration method of a user equipment (UE) in a wireless communication system is disclosed. The registration method includes transmitting a registration request message to an access and mobility management function (AMF), wherein the registration request message includes requested network slice selection assistance information (NSSAI) including single (S)-NSSAI corresponding to a network slice to which the UE intends to register with; and receiving, from the AMF, a registration accept message as a response to the registration request message, wherein if at least one of the S-NSSAI included in the requested NSSAI is rejected by the AMF, the registration accept message includes the rejected S-NSSAI and a reason for refusal for the rejected S-NSSAI.