Method and apparatus for dynamic network slice selection in wireless communication system

Abstract

In an embodiment of the present disclosure, a method for operating an access and mobility management function (AMF) in a wireless communication system is provided. The method may comprise the steps of: transmitting a subscription information request message corresponding to a UE to a unified data management (UDM); receiving a notification message regarding updated subscription information from the UDM; determining whether or not to update network slice-related UE configuration information with regard to the UE; transmitting updated UE configuration information to the UE if the network slice-related UE configuration information has been updated; and receiving a message indicating that configuration information update has been completed from the UE.

Description

Method and device for dynamic network slice selection in a wireless communication system

[0001] The present invention relates to a method and device for dynamic network slice selection in a wireless communication system.

[0002] To meet the growing demand for wireless data traffic following the commercialization of 4G (4th generation) communication systems, efforts are being made to develop improved 5G (5th generation) communication systems, or pre-5G communication systems. For this reason, 5G communication systems, or pre-5G communication systems, are also referred to as "Beyond 4G Network" or "Post-LTE" systems. To achieve high data rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (e.g., the 60 GHz band). To mitigate radio wave path loss and increase the transmission range of radio waves in ultra-high frequency bands, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, and large-scale antenna technologies are being discussed in 5G communication systems. In addition, to improve the network of the system, technologies such as evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, moving networks, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation are being developed in 5G communication systems.In addition, advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), as well as advanced access technologies such as FBMC (Filter Bank Multi Carrier), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access) are being developed in 5G systems.

[0003] Meanwhile, the Internet is evolving from a human-centric network where humans create and consume information to an Internet of Things (IoT) network where information is exchanged and processed between distributed components, such as objects. The Internet of Everything (IoE) is also emerging, combining IoT technologies with big data processing technologies, such as those connected to cloud servers. To implement the IoT, technological elements such as sensing technology, wireless and wired communication and network infrastructure, service interface technology, and security technology are required. Recently, research is being conducted on technologies such as sensor networks, Machine-to-Machine (M2M), and Machine-Type Communication (MTC) for connecting objects. In the IoT environment, intelligent IT (Information Technology) services can be provided that collect and analyze data generated from connected objects to create new value in human lives. Through the convergence and integration of existing IT technologies with various industries, the IoT can be applied to areas such as smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0004] Accordingly, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) are being implemented using 5G communication techniques such as beamforming, MIMO, and array antennas. The application of cloud radio access networks (cloud RAN), a big data processing technology described above, can also be considered an example of the convergence of 5G and IoT technologies.

[0005] Additionally, efforts are underway to develop a 6G communication system that will be approximately five times faster than the maximum speed of 5G. Accordingly, implementation in higher frequency bands than 5G is being considered to achieve higher data rates.

[0006] As wireless communication systems have developed as described above, they have become capable of providing various services, and in particular, a method to support session continuity for providing services continuously is required.

[0007] One embodiment of the present disclosure can provide a method and device for effectively providing a service in a wireless communication system.

[0008] A method for operating an AMF (Access and Mobility Management Function) in a wireless communication system disclosed as a technical means for achieving the above-described technical task may include a step of transmitting a subscription information request message corresponding to a terminal to a UDM (Unified Data Management), a step of receiving a notification message for updated subscription information from the UDM, a step of determining whether to update terminal configuration information related to a network slice for the terminal, a step of transmitting the updated terminal configuration information to the terminal when the terminal configuration information related to the network slice is updated, and a step of receiving a message indicating that the update of the configuration information is completed from the terminal.

[0009] A method for operating Unified Data Management (UDM) in a wireless communication system disclosed as a technical means for achieving the above-described technical task may include the steps of receiving a subscription information request message corresponding to a terminal from an Access and Mobility Management Function (AMF), receiving a message including information for selecting or reselecting a network slice from an Application Function (AF), identifying a Subscription Permanent Identifier (SUPI) associated with the terminal, transmitting a request message for obtaining subscriber information for the SUPI to a unified data repository (UDR), and obtaining the subscriber information from the UDR, transmitting a message for updating subscriber information to the UDR, transmitting a notification message for the updated subscription information to the AMF, receiving a subscription information request message for the terminal from the AMF, and transmitting the updated subscription information to the AMF in response to the subscription information request message.

[0010] A method for operating a Policy Control Function (PCF) in a wireless communication system disclosed as a technical means for achieving the above-described technical task may include the steps of: receiving a subscription information request message corresponding to a terminal from an Access and Mobility Management Function (AMF); receiving a message including information for selecting or reselecting a network slice from an Application Function (AF); transmitting a request message for obtaining subscriber information for a Subscription Permanent Identifier (SUPI) associated with the terminal to a unified data repository (UDR) and obtaining the subscriber information from the UDR; transmitting a message for updating subscriber information to the UDR; transmitting a notification message for the updated subscription information to the AMF; receiving a policy information request message for the terminal from the AMF; identifying subscription information stored in the UDR based on the policy information request message; and transmitting the updated subscription information to the AMF in response to the policy information request message.

[0011] FIG. 1 illustrates the structure of a 5G system according to one embodiment of the present disclosure.

[0012] FIG. 2 illustrates a dynamic network slice selection method in a wireless communication system according to one embodiment of the present disclosure.

[0013] FIG. 3 illustrates a dynamic network slice selection method in a wireless communication system according to one embodiment of the present disclosure.

[0014] FIG. 4 is a diagram illustrating a network entity according to one embodiment of the present disclosure.

[0015] In describing the embodiments herein, descriptions of technical details that are well-known in the technical field to which the present invention pertains and are not directly related to the present invention will be omitted. This is to avoid obscuring the gist of the present invention by omitting unnecessary explanations and to convey the gist more clearly.

[0016] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below, along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms.

[0017] The terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc. are provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0018] For convenience of explanation, this disclosure uses terms and names defined in the 3rd Generation Partnership Project New Radio (3GPP NR) standards. However, this disclosure is not limited to these terms and names and can be equally applied to systems conforming to other standards. In this disclosure, a base station may refer to a gNB. Furthermore, the term "terminal" may refer to mobile phones, NB-IoT devices, sensors, and other wireless communication devices.

[0019] Hereinafter, a base station is an entity that performs resource allocation for a terminal, and may be at least one of a gNode B, an eNode B, a Node B, a BS (Base Station), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. Of course, the above examples are not limited thereto.

[0020] This disclosure can be applied to 3GPP NR (the 5th generation mobile communications standard). Furthermore, this disclosure can be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart or connected cars, healthcare, digital education, retail, security, and safety-related services) based on 5G communication technology and IoT-related technologies.

[0021] Wireless communication systems are evolving from providing voice-oriented services in the early days to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards such as 3GPP's HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2's HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE's 802.16e.

[0022] As a representative example of a broadband wireless communication system, the LTE system adopts the OFDM (Orthogonal Frequency Division Multiplexing) method in the downlink (DL) and the SC-FDMA (Single Carrier Frequency Division Multiple Access) method in the uplink (UL). The uplink refers to a wireless link in which a terminal (User Equipment; UE or Mobile Station; MS; eNode B or BS; Base Station) transmits data or control signals to a base station, and the downlink refers to a wireless link in which a base station transmits data or control signals to a terminal. The above multiple access method distinguishes the data or control information of each user by allocating and operating the time-frequency resources to be used to transmit data or control information to each user so that they do not overlap, that is, so as to achieve orthogonality.

[0023] As the future communications system beyond LTE, 5G communication systems must be able to freely reflect the diverse needs of users and service providers. Therefore, they must support services that simultaneously satisfy these diverse requirements. Services being considered for 5G communication systems include Enhanced Mobile Broadband (eMBB), Massive Machine Type Communication (mMTC), and Ultra Reliability Low Latency Communication (URLLC).

[0024] Furthermore, while embodiments of the present invention will be described below using LTE, LTE-A, LTE Pro, or 5G (or NR, next-generation mobile communication) systems as examples, the embodiments of the present invention may also be applied to other communication systems with similar technical backgrounds or channel types. Furthermore, embodiments of the present invention may be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present invention.

[0025] In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Hereinafter, embodiments of the present disclosure will be described with reference to the attached drawings.

[0026] FIG. 1 illustrates the structure of a 5G system according to various embodiments of the present disclosure.

[0027] The 5G mobile communication network is composed of 5G UE (user equipment, terminal), 5G RAN (radio access network, base station), gNB (5G nodeB), eNB (evolved nodeB, etc.), and 5G core network. The 5G core network can be composed of NFs such as AMF (access and mobility management function) that provides UE mobility management function, SMF (session management function) that provides session management function, UPF (user plane function) that performs data transfer role, PCF (policy control function) that provides policy control function, UDM (unified data management) that provides data management function such as subscriber data and policy control data, and UDR (unified data repository) that stores data of various network functions (NFs) such as UDM. The 5G core network can also be composed of NFs such as NSSF (network slice selection function), NWDAF (network data analytic function), AF (application function), DN (data network), NSACF (network slice admission control function).

[0028] In the 3GPP system, a conceptual link connecting NFs within a 5G system is defined as a reference point. For example, referring to Figure 1, the reference points included in the 5G system architecture may be as follows:

[0029] - N1: Reference point between UE and AMF

[0030] - N2: Reference point between (R)AN and AMF

[0031] - N3: Reference point between (R)AN and UPF

[0032] - N4: Reference point between SMF and UPF

[0033] - N5: Reference point between PCF and AF

[0034] - N6: Reference point between UPF and DN

[0035] - N7: Reference point between SMF and PCF

[0036] - N8: Reference point between UDM and AMF

[0037] - N9: Reference point between two core UPFs

[0038] - N10: Reference point between UDM and SMF

[0039] - N11: Reference point between AMF and SMF

[0040] - N12: Reference point between AMF and authentication server function (AUSF)

[0041] - N13: Reference points between UDM and AUSF

[0042] - N14: Reference point between two AMFs

[0043] - N15: Reference point between PCF and AMF for non-roaming scenarios, reference point between PCF and AMF in visited network for roaming scenarios.

[0044] In 5G systems, network slicing technology refers to the technology and architecture that enables multiple virtualized, independent, logical networks within a single physical network. Network operators provide services by configuring virtual end-to-end networks called network slices to meet the specialized requirements of services or applications. At this time, network slices can be distinguished by an identifier called single-network slice selection assistance information (S-NSSAI). During the UE registration procedure (e.g., UE registration procedure), the network transmits a set of allowed slices (e.g., allowed NSSAI(s)) to the UE, and the UE transmits and receives application data through a PDU (protocol data unit) session created through one of these S-NSSAIs (i.e., network slices).

[0045] FIG. 2 illustrates a method for dynamic network slice selection in a wireless communication system according to one embodiment of the present disclosure. FIG. 2 illustrates a method for providing network slice selection information in a registration procedure according to one embodiment of the present disclosure. Not all steps illustrated in FIG. 2 are essential components, and some steps may be omitted in one embodiment.

[0046] In step 0, the AMF may perform a subscription request to the UDM for subscriber information about the UE. The message may include a Subscription Permanent Identifier (SUPI), which is a UE identifier. In an embodiment where the PCF is used instead of the UDM, the AF may perform a subscription request to the PCF for subscriber information about the UE. If the PCF is used instead of the UDM, the PCF may be applied instead of the UDM in the following description.

[0047] In step 1, the AF can send a message (e.g., Nnef_ParameterProvision_Create, Update, or Delete message) containing information for network slice selection or reselection to the UDM via the network exposure function (NEF).

[0048] In embodiments where PCF is used instead of UDM, AF may send a message (Nnef_AMInfluence_Create, Update, or Delete message) containing information for network slice selection or reselection to PCF via NEF.

[0049] If the AF sends a message directly to the UDM (or PCF), the AF may send the message of step 2 (e.g., Nudm_ParameterProvision_Create, Update, or Delete message) directly to the UDM (or PCF) without going through the NEF.

[0050] Messages sent by AF to NEF (or to UDM) may contain the following information:

[0051] - UE identifier information: May include a Generic Public Subscription Identifier (GPSI) or a Subscription Permanent Identifier (SUPI). Or, an External Group ID representing multiple UEs may be included.

[0052] - Transaction Reference ID: If AF wants to update or delete information from NEF that already exists through a request (for example, by sending an update or delete message), it can include the corresponding Transaction Reference ID.

[0053] - Network Slice Selection Information: Network slice selection information for the terminal, which may include one or more of S-NSSAI(s) information to be used by the terminal, information on other S-NSSAI(s) to be used instead of each S-NSSAI (other S-NSSAI(s) per S-NSSAI), and information on S-NSSAI(s) to be used per application identifier (or per application category identifier). In addition, information on the time at which the S-NSSAI information to be used instead of each S-NSSAI is to be applied (e.g., start time, end time, duration, etc.) may be included.

[0054] - Priority information: Information indicating the priority for applying slice selection information for each terminal may be included. If the S-NSSAI to be used instead of the slice selection information (e.g., an alternative S-NSSAI) is congested, the network can decide whether to allow the terminal to use the alternative S-NSSAI based on the priority for applying the slice selection information.

[0055] In embodiments where PCF is used instead of UDM, the information provided by AF may include an application identifier (e.g., Application ID or AF Service ID).

[0056] When the NEF receives a message from the AF in step 1, it performs authorization for the AF's request. If authorization fails, steps 2 to 5 are skipped and the NEF can transmit a response message including information indicating failure or rejection to the AF in step 6. For example, the NEF can transmit a response message including information indicating failure or rejection if the S-NSSAI(s) included in the AF's request message are not included in the subscriber information of the UE included in the AF's request message.

[0057] If authorization for the AF request is successful, in step 2, the NEF can send a message to the UDM (or PCF) based on the message received in step 1. If the NEF received the create message in step 1, it can generate a Transaction Reference ID. The message that the NEF sends to the UDM (or PCF) may include the information contained in the message received in step 1.

[0058] In step 3, if the message received in step 2 contains a UE identifier other than SUPI, the UDM can identify the SUPI associated with the UE based on the stored information. If the message received in step 2 contains an External Group ID, the UDM can identify the corresponding Internal Group ID based on the stored information.

[0059] The UDM may obtain subscriber information for the corresponding SUPI(s) from the UDR by transmitting a request message to the UDR to obtain subscriber information for the corresponding SUPI(s) in order to authenticate the change of subscriber information according to the request of step 2 for the terminals (e.g., SUPI(s)) corresponding to the request of step 2.

[0060] In embodiments where PCF is used instead of UDM, PCF may obtain information from UDR by transmitting a request message to UDR to obtain subscriber information for corresponding SUPI(s) or Application ID in order to authenticate the change of subscriber information according to the request of step 2 for the terminals (e.g., SUPI(s)) corresponding to the request of step 2.

[0061] In Step 4, if the subscriber information change authentication in Step 3 was successful, the UDM (or PCF) may send a message to the UDR to update the subscriber information. The message may include the following information:

[0062] - SUPI

[0063] - S-NSSAI(s) per S-NSSAI: The Network Slice Selection Information included in the message of Step 1 described above may be included as is, or information derived based on the information may be included. For example, information on other slice identifier(s) to be used instead for each slice may be included. In this case, S-NSSAI(s) may be included for each S-NSSAI included in the Subscribed S-NSSAI(s) for the UE.

[0064] - Subscribed S-NSSAI(s): If the message of step 1 described above includes S-NSSAI(s) for the UE, when updating the Subscribed S-NSSAI(s) for the UE based on the S-NSSAI(s) information, the Subscribed S-NSSAI(s) configured based on the S-NSSAI(s) for the UE may be included.

[0065] When UDR receives an update message from UDM (or PCF), it can update the subscription information stored in UDR using the SUPI included in the message as a data key. UDR can update the related subscription information based on the information included in the message (e.g., S-NSSAI(s) per S-NSSAI or Subscribed S-NSSAI(s)). If there is existing corresponding subscription information (e.g., subscription information corresponding to S-NSSAI(s) per S-NSSAI or Subscribed S-NSSAI(s)), UDR can overwrite it based on the information included in the message received from UDM (or PCF). If there is no existing corresponding subscription information, UDR can add new subscription information (e.g., subscription information corresponding to S-NSSAI(s) per S-NSSAI or Subscribed S-NSSAI(s)) based on the information included in the message received from UDM (or PCF).

[0066] In step 5, the UDM (or PCF) may send a response message to the request message of step 2 described above to the NEF (or to the AF, if the AF directly requested it). The message may include processing result information for the request of step 2.

[0067] In step 6, when the NEF receives the message of step 5, it may transmit a response message to the message of step 1 described above to the AF. The message may include processing result information for the request of step 1.

[0068] In step 7, if the UDM (or PCF) has updated the subscription information (e.g., the subscription information corresponding to S-NSSAI(s) per S-NSSAI or Subscribed S-NSSAI(s)) (or policy information in an embodiment where the PCF is used) in step 4 described above, the UDM (or PCF) may send a notification message to an NF (e.g., AMF) subscribed to the subscription information (or policy information in an embodiment where the PCF is used). If the information stored in the UDR includes time information together with the S-NSSAI(s) per S-NSSAI (e.g., information on the slice identifier that needs to be changed and the slice identifier to be used instead), the UDM or PCF may send a notification message to the AMF at the time when the S-NSSAI(s) per S-NSSAI should be applied according to the time information. Additionally, the UDM or PCF may send a notification message to the AMF for release (e.g., a notification message for replacement with an existing slice) at the time when the S-NSSAI(s) per S-NSSAI should be released based on the corresponding time information. In this case, the notification message may only contain the identifier of the existing slice that was replaced.

[0069] Additionally, if a slice to be used instead (e.g., a replacement slice) included in the information stored in the UDR is currently congested, the UDM or PCF may not send a notification message to the AMF. Alternatively, if a slice to be used instead (e.g., a replacement slice) included in the information stored in the UDR is currently congested and the information stored in the UDR contains Priority Information indicating a high priority, the UDM or PCF may send a notification message to the AMF in charge of the UE. Additionally, the UDM or PCF may send a notification message to the AMF in charge of the UE to no longer use the slice to be used instead (e.g., a replacement slice) for a UE with lower Priority Information.

[0070] At this time, the notification message may contain the following information:

[0071] - SUPI or Internal Group Identifier: SUPI (i.e. UE identifier) ​​or Internal Group Identifier may be included.

[0072] - S-NSSAI(s) may contain subscription information corresponding to each S-NSSAI.

[0073] - Subscribed S-NSSAI(s) may be included.

[0074] In step 8a, when the AMF receives the notification message of step 7, it can decide whether to update the terminal configuration information related to the network slice for the terminal for the message. In addition, when the AMF receives the message of step 11 described below, if there is a PDU session for the S-NSSAI that needs to be changed, it can send a message to the SMF in charge of the session requesting replacement of the network slice with an alternative S-NSSAI based on the information included in the message received in step 7.

[0075] If NSSF is used, AMF can send a message to NSSF to ask for terminal configuration information. At this time, if the message received in step 7 includes Subscribed S-NSSAI(s), AMF can include the Subscribed S-NSSAI(s) received in step 7 in the message sent to NSSF.

[0076] If NSSF is used, the AMF may, if the message received in step 7 includes S-NSSAI(s) per S-NSSAI (e.g., information about alternative slice identifiers to be used instead of the corresponding slice for each network slice identifier that needs to be changed), derive a Requested NSSAI (e.g., information about network slice identifiers requested by the UE) based on the alternative slice identifiers included in the information and include it in a message (e.g., Nnssf_NSSelection Get request) to the NSSF, or instead of sending the message to the NSSF, the AMF may check whether there is an S-NSSAI that needs to be changed to the existing Allowed NSSAI for the UE, and if there is, the AMF may generate (or update) slice identifier information (e.g., Mapping of Alternative S-NSSAI) to be used instead of the S-NSSAI that needs to be changed based on the S-NSSAI(s) per S-NSSAI. AMF may update Allowed NSSAI if Allowed NSSAI does not contain a slice identifier to be used instead (e.g., Alternative S-NSSAI). AMF may update Configured NSSAI if Configured NSSAI does not contain a slice identifier to be used instead (e.g., Alternative S-NSSAI).When an update occurs among Allowed NSSAI, Configured NSSAI, or Mapping of Alternative S-NSSAI, AMF may include the corresponding configuration information (e.g., one or more of Allowed NSSAI, Configured NSSAI, or Mapping of Alternative S-NSSAI) in the UE Configuration Update Command message transmitted to the UE through the RAN.

[0077] The NSSF may derive Allowed NSSAI and / or Configured NSSAI based on the message received from the AMF, and include Allowed NSSAI and / or Configured NSSAI in the response message transmitted to the AMF. If the response message received from the NSSF includes Allowed NSSAI or Configured NSSAI, the AMF may include corresponding configuration information (e.g., one or more of Allowed NSSAI and Configured NSSAI) in the UE Configuration Update Command message transmitted to the UE via the RAN.

[0078] If AMF does not use NSSF and the message received in step 7 contains Subscribed S-NSSAI(s), AMF may perform update of Allowed NSSAI and / or Configured NSSAI based on the updated Subscribed S-NSSAI(s). AMF may include corresponding configuration information (e.g., one or more of Allowed NSSAI, Configured NSSAI) in the UE Configuration Update Command message sent to UE via RAN if an update occurs for one or more of Allowed NSSAI, Configured NSSAI.

[0079] If AMF does not use NSSF and the message received in step 7 contains S-NSSAI(s) per S-NSSAI (e.g., information about alternative slice identifiers to use instead of the corresponding slice for each network slice identifier that needs to be changed), AMF can check if there is an S-NSSAI that needs to be changed to the existing Allowed NSSAI for the UE. If there is an S-NSSAI that needs to be changed to the existing Allowed NSSAI for the UE, AMF can derive slice identifier information (e.g., Mapping of Alternative S-NSSAI) to use instead of the S-NSSAI that needs to be changed based on S-NSSAI(s) per S-NSSAI. When an update occurs among Allowed NSSAI, Configured NSSAI, or Mapping of Alternative S-NSSAI, AMF may include the corresponding configuration information (e.g., one or more of Allowed NSSAI, Configured NSSAI, or Mapping of Alternative S-NSSAI) in the UE Configuration Update Command message transmitted to the UE through the RAN.

[0080] If the message received in step 8a includes Allowed NSSAI, the UE may delete the previously stored Allowed NSSAI and store the Allowed NSSAI included in the received message. If the message received in step 8a includes Configured NSSAI, the UE may delete the previously stored Configured NSSAI and store the Configured NSSAI included in the received message. If the message received in step 8a includes Mapping of Alternative S-NSSAI, the UE may delete the previously stored Mapping of Alternative S-NSSAI and store the Mapping of Alternative S-NSSAI included in the received message. If the UE receives Mapping of Alternative S-NSSAI (e.g., information indicating to use Alternative S-NSSAI instead of S-NSSAI), the UE may use the Alternative S-NSSAI instead of the existing S-NSSAI included in the information. For example, if a session is required for application data transmission to an existing S-NSSAI, a session establishment request message for data transmission to an Alternative S-NSSAI may be transmitted instead of the S-NSSAI. However, the session establishment request message may include information about the existing S-NSSAI along with the Alternative S-NSSAI.

[0081] In step 8b, the UE may send a message to the AMF via the RAN indicating that the configuration information update is complete via the message received in step 8a.

[0082] In step 9, the UE may send a registration request message to the AMF via the RAN. The registration request message may be an initial registration request (e.g., a registration request with the registration type set to initial registration) or a mobility registration update request (e.g., a registration request with the registration type set to mobility registration).

[0083] In step 10, the AMF may send a request message including SUPI to the UDM to receive subscription information for the UE. In one embodiment, the AMF may also send a request message including SUPI to the PCF to receive policy information for the UE.

[0084] In step 11, upon receiving the message of step 10, the UDM can obtain the subscription information stored in the UDR through the SUPI included in the received message. The UDM can include the subscription information in the response message sent to the AMF. The subscription information may include the information updated through step 4 described above.

[0085] In one embodiment, upon receiving the message of step 10, the PCF may obtain subscription information stored in the UDR through the SUPI included in the received message. This information may include information updated through step 4 described above.

[0086] If the information stored in the UDR includes time information along with S-NSSAI(s) per S-NSSAI (e.g., information on the slice identifier that needs to be changed and the slice identifier to be used instead), the UDM or PCF may send a notification message to the AMF at the time when the S-NSSAI(s) per S-NSSAI should be applied according to the time information. In addition, the UDM or PCF may send a notification message for release (e.g., a notification message for replacement with an existing slice) to the AMF at the time when the S-NSSAI(s) per S-NSSAI should be released according to the time information. In this case, the notification message may only include the existing slice identifier that was replaced.

[0087] In step 12, when the AMF receives the message of step 11, it can derive terminal configuration information related to the network slice for the terminal for the message. In addition, when the AMF receives the message of step 11, if there is a PDU session for the S-NSSAI that needs to be changed, it can send a message to the SMF in charge of the session requesting replacement of the network slice with an alternative S-NSSAI based on the information contained in the message received in step 7 described above.

[0088] When using NSSF, AMF may send a message to NSSF to request terminal configuration information. If the message received in step 11 includes Subscribed S-NSSAI(s), AMF may include the Subscribed S-NSSAI(s) received in step 11 in the message sent to NSSF.

[0089] When using NSSF, if the message received in step 11 includes S-NSSAI(s) per S-NSSAI (e.g., information about alternative slice identifiers to be used instead of the corresponding slice for each network slice identifier that needs to be changed), the AMF may derive a Requested NSSAI (e.g., information about network slice identifiers requested by the UE) based on the alternative slice identifiers included in the information and include it in a message to be sent to the NSSF (e.g., Nnssf_NSSelection Get request), or instead of sending the message to the NSSF, the AMF may check whether there is an S-NSSAI that needs to be changed to the existing Allowed NSSAI for the UE, and if there is, the AMF may generate (or update) slice identifier information to be used instead of the S-NSSAI that needs to be changed (e.g., Mapping of Alternative S-NSSAI) based on the S-NSSAI(s) per S-NSSAI. AMF may update Allowed NSSAI if Allowed NSSAI does not contain a slice identifier to be used instead (e.g., Alternative S-NSSAI). AMF may update Configured NSSAI if Configured NSSAI does not contain a slice identifier to be used instead (e.g., Alternative S-NSSAI).When an update occurs among Allowed NSSAI, Configured NSSAI, or Mapping of Alternative S-NSSAI, AMF may include the corresponding configuration information (e.g., one or more of Allowed NSSAI, Configured NSSAI, or Mapping of Alternative S-NSSAI) in the registration accept message sent to the UE via RAN.

[0090] The NSSF may derive Allowed NSSAI and / or Configured NSSAI based on the message received from the AMF, and include Allowed NSSAI and / or Configured NSSAI in the response message transmitted to the AMF. If the response message received from the NSSF includes Allowed NSSAI or Configured NSSAI, the AMF may include corresponding configuration information (e.g., one or more of Allowed NSSAI and Configured NSSAI) in the registration accept message transmitted to the UE via the RAN.

[0091] If AMF does not use NSSF and the message received in step 11 contains Subscribed S-NSSAI(s), AMF may perform update of Allowed NSSAI and / or Configured NSSAI based on the updated Subscribed S-NSSAI(s). AMF may include corresponding configuration information (e.g., one or more of Allowed NSSAI, Configured NSSAI) in the registration accept message sent to UE via RAN if an update occurs for one or more of Allowed NSSAI, Configured NSSAI.

[0092] If AMF does not use NSSF and the message received in step 11 contains S-NSSAI(s) per S-NSSAI (e.g., information about alternative slice identifiers to use instead of the corresponding slice for each network slice identifier that needs to be changed), AMF can check if there is an S-NSSAI that needs to be changed to the existing Allowed NSSAI for the UE. If there is an S-NSSAI that needs to be changed to the existing Allowed NSSAI for the UE, AMF can derive slice identifier information (e.g., Mapping of Alternative S-NSSAI) to use instead of the S-NSSAI that needs to be changed based on S-NSSAI(s) per S-NSSAI. When an update occurs among Allowed NSSAI, Configured NSSAI, or Mapping of Alternative S-NSSAI, AMF may include the corresponding configuration information (e.g., one or more of Allowed NSSAI, Configured NSSAI, or Mapping of Alternative S-NSSAI) in the registration accept message sent to the UE via RAN.

[0093] If the message received in step 12 includes Allowed NSSAI, the UE may delete the previously stored Allowed NSSAI and store the Allowed NSSAI included in the received message. If the message received in step 12 includes Configured NSSAI, the UE may delete the previously stored Configured NSSAI and store the Configured NSSAI included in the received message. If the message received in step 12 includes Mapping of Alternative S-NSSAI, the UE may delete the previously stored Mapping of Alternative S-NSSAI and store the Mapping of Alternative S-NSSAI included in the received message. If the UE receives Mapping of Alternative S-NSSAI (e.g., information indicating to use Alternative S-NSSAI instead of S-NSSAI), the UE may use the Alternative S-NSSAI instead of the existing S-NSSAI included in the information. For example, if a session is required for application data transmission to an existing S-NSSAI, a session establishment request message for data transmission to an Alternative S-NSSAI may be transmitted instead of the S-NSSAI. However, the session establishment request message may include information about the existing S-NSSAI along with the Alternative S-NSSAI.

[0094] FIG. 3 illustrates a dynamic network slice selection method in a wireless communication system according to one embodiment of the present disclosure. Not all steps illustrated in FIG. 3 are essential components, and some steps may be omitted in one embodiment.

[0095] In step 1, the AMF sends an AM Policy Association establishment request message to the PCF, and the PCF can create an AM Policy and send a response message to the AMF. The PCF can send a message to the binding support function (BSF) to register itself as the responsible PCF for the UE. The message sent by the PCF to the BSF can include the PCF ID and the UE ID (e.g., SUPI or GPSI).

[0096] In step 2a, the AF may send subscription request information to the BSF, either through the NEF or directly, requesting that the BSF notify the UE when a new PCF is registered for the UE.

[0097] In step 2b, after receiving the request in step 2a, the BSF may send a notification message including the corresponding PCF ID to the AF, either through NEF or directly, if a new PCF registration occurs for the corresponding UE (e.g., AM Policy Association Establishment in step 1).

[0098] In step 2c, the AF may decide to provide network slice selection information (e.g., Network Slice Selection Information) to the UE. This may occur in the following cases: for example, when the AF requests that the UE use a different network slice due to a problem with the network slice the UE was previously using, or when the network slice used by the UE needs to be changed due to a change in the user's tariff plan or membership.

[0099] If the AF decides to provide Network Slice Selection Information, it may send a request message to the PCF, AMF or UDM to obtain network slice information for the UE (e.g., one or more of Allowed NSSAI, Subscribed S-NSSAI(s), Requested NSSAI). Upon receiving the message, the PCF, AMF or UDM may include the network slice information for the UE (e.g., one or more of Allowed NSSAI, Subscribed S-NSSAI(s), Requested NSSAI) in a response message sent to the AF.

[0100] In step 2d, if AF decides to provide Network Slice Selection Information, it may send a request message to PCF, either through NEF or directly, containing the following information:

[0101] - UE identifier information: May include a Generic Public Subscription Identifier (GPSI) or a Subscription Permanent Identifier (SUPI). Or, an External Group ID representing multiple UEs may be included.

[0102] - Network Slice Selection Information: Network slice selection information for the terminal, which may include one or more of the following: information on S-NSSAI(s) to be used by the terminal, information on other S-NSSAI(s) to be used instead of each S-NSSAI (other S-NSSAI(s) per S-NSSAI), or information on S-NSSAI(s) to be used per application identifier (or per application category identifier).

[0103] In step 3, the PCF may decide to update the policy if it receives the message of step 2d and if the message includes Network Slice Selection Information. If the message of step 2d includes S-NSSAI(s) per S-NSSAI (e.g., information on alternative slice identifiers to be used instead of the corresponding slice for each network slice identifier for one or more network slice identifiers that need to be changed), the PCF may derive a policy including information (Alternative S-NSSAI) indicating that the UE will use an alternative network slice instead of the existing network slice.

[0104] In Step 4, the PCF may send the updated policy from Step 3 to the AMF in a notification message. The notification message may include one or more of the following information:

[0105] - Alternative S-NSSAI(s) per S-NSSAI

[0106] - UE ID (GPSI, SUPI, or UE Address): UE identifier information

[0107] - Policy Association ID: Information that identifies the policy

[0108] In steps 5a and 5b, the same procedure as steps 8a and 8b of FIG. 2 described above can be performed.

[0109] In step 6, the PCF may send a notification message to the AF indicating that the network slice selection information has been reflected.

[0110] FIG. 4 is a diagram illustrating a network entity (400) according to one embodiment of the present disclosure. In one embodiment, the network entity (400) may correspond to an NSSF, an NWDAF, an UDM, an NSACF, an AMF, an SMF, a PCF, an AF, a UE, a RAN, an AN, an UPF, a DN, an UDR, an NEF, or a BSF illustrated in FIG. 1, FIG. 2, or FIG. 3 described above.

[0111] Referring to FIG. 4, the network entity (400) may be composed of a transceiver (410), a processor (420), and a memory (430). Depending on the communication method of the network entity (400) described above, the transceiver (410), the processor (420), and the memory (430) of the network entity (400) may operate. However, the components of the network entity (400) are not limited to the examples described above. For example, the network entity (400) may include more components than the components described above. In one embodiment, the transceiver (410), the processor (420), and the memory (430) may be implemented in the form of a single chip. In addition, the processor (420) may include one or more processors.

[0112] The transceiver (410) is a general term for the receiver of the network entity (400) and the transmitter of the network entity (400), and can transmit and receive signals with a terminal or base station. The signals transmitted and received with the terminal or base station may include control information and data.

[0113] Additionally, the transceiver (410) can perform functions for transmitting and receiving signals via a wireless channel. For example, the transceiver (410) can receive a signal via a wireless channel, output it to the processor (420), and transmit the signal output from the processor (420) via the wireless channel.

[0114] The memory (430) can store programs and data required for the operation of the network entity (400). In addition, the memory (430) can store control information or data included in a signal acquired from the network entity (400). The memory (430) can be configured as a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, or a combination of storage media. In addition, the memory (430) may not exist separately but may be configured as included in the processor (420). The memory (430) can be configured as a volatile memory, a nonvolatile memory, or a combination of volatile and nonvolatile memories. In addition, the memory (430) can provide stored data upon request of the processor (420).

[0115] The processor (420) may control a series of processes so that the network entity (400) can operate according to the embodiments of the present disclosure described above. For example, the processor (420) may receive control signals and data signals through the transceiver (410) and process the received control signals and data signals. The processor (420) may transmit the processed control signals and data signals through the transceiver (410). In addition, the processor (420) may write or read data to or from the memory (430). The processor (420) may perform functions of a protocol stack required by a communication standard. For this purpose, the processor (420) may include at least one processor or microprocessor. In one embodiment, a portion of the transceiver (410) or the processor (420) may be referred to as a communication processor (CP).

[0116] The above description of the present disclosure is provided for illustrative purposes only, and those skilled in the art will readily appreciate that modifications to other specific forms can be made without altering the technical spirit or essential features of the present disclosure. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, components described as being single may be implemented in a distributed manner, and similarly, components described as being distributed may be implemented in a combined manner.

[0117] The scope of the present disclosure is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present disclosure.

Claims

1. In a method for operating AMF (Access and Mobility Management Function) in a wireless communication system, A step of transmitting a subscription information request message corresponding to a terminal using UDM (Unified Data Management); A step of receiving a notification message regarding updated subscription information from the above UDM; A step for determining whether to update terminal setting information related to network slice for the above terminal; When the terminal setting information related to the above network slice is updated, a step of transmitting the updated terminal setting information to the terminal; and A method comprising the step of receiving a message indicating that update of setting information has been completed from the terminal.

2. A method in the first paragraph, wherein the subscription information request message includes an identifier of the corresponding terminal.

3. A method according to claim 1, wherein a notification message for the updated subscription information is received based on time information stored in the UDR.

4. In a method for operating UDM (Unified Data Management) in a wireless communication system, A step of receiving a subscription information request message corresponding to a terminal from an AMF (Access and Mobility Management Function); A step of receiving a message including information for selecting or reselecting a network slice from an AF (Application Function); A step of identifying a SUPI (Subscription Permanent Identifier) associated with the terminal; A step of transmitting a request message to a UDR (unified data repository) to obtain subscriber information for the SUPI, and obtaining the subscriber information from the UDR; A step of transmitting a message for updating subscriber information to the above UDR; A step of sending a notification message regarding the subscription information updated to the above AMF; A step of receiving a subscription information request message for the terminal from the AMF; and A method comprising the step of transmitting updated subscription information to the AMF in response to the subscription information request message.

5. A method in accordance with claim 4, wherein the subscription information request message includes an identifier of the corresponding terminal.

6. A method in accordance with claim 4, wherein a message including information for selecting or reselecting a network slice includes at least one of UE identifier information, a Transaction Reference identifier, network slice selection information, or information indicating a priority for applying slice selection information.

7. A method in paragraph 4, wherein the message for updating subscriber information includes at least one of SUPI, S-NSSAI information, or subscribed S-NSSAI information.

8. A method according to claim 4, wherein a notification message for the updated subscription information is transmitted based on time information stored in the UDR.

9. A method in accordance with claim 4, wherein the notification message for the updated subscription information includes at least one of SUPI, an internal group identifier, S-NSSAI information, or subscribed S-NSSAI information.

10. In a method for operating PCF (Policy Control Function) in a wireless communication system, A step of receiving a subscription information request message corresponding to a terminal from an AMF (Access and Mobility Management Function); A step of receiving a message including information for selecting or reselecting a network slice from an AF (Application Function); A step of transmitting a request message to a UDR (unified data repository) to obtain subscriber information for a SUPI (Subscription Permanent Identifier) associated with the terminal, and obtaining the subscriber information from the UDR; A step of transmitting a message for updating subscriber information to the above UDR; A step of sending a notification message regarding the subscription information updated to the above AMF; A step of receiving a policy information request message for the terminal from the AMF; A step of identifying subscription information stored in the UDR based on the above policy information request message; and A method comprising the step of transmitting updated subscription information to the AMF in response to the policy information request message.

11. A method in claim 10, wherein the subscription information request message includes an identifier of the corresponding terminal.

12. A method in accordance with claim 10, wherein a message including information for selecting or reselecting a network slice includes at least one of UE identifier information, a Transaction Reference identifier, network slice selection information, or information indicating a priority for applying slice selection information.

13. A method in claim 10, wherein the message for updating subscriber information includes at least one of SUPI, S-NSSAI information, or subscribed S-NSSAI information.

14. A method according to claim 10, wherein a notification message for the updated subscription information is transmitted based on time information stored in the UDR.

15. A method in claim 10, wherein the notification message for the updated subscription information includes at least one of SUPI, an internal group identifier, S-NSSAI information, or subscribed S-NSSAI information.

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