Enhancements for user equipment network slice management

Abstract

To solve a problem in which it has been identified that UE may not properly consider the NSSAI mapping during UE mobility from the HPLMN to the VPLMN or vice versa, which may cause inconsistencies between the UE and a network, which may lead to unpredictable behavior (e.g., releasing PDU sessions) and poor user experience.SOLUTION: In a network architecture, user equipment (UE) sends a registration request message including a request to register to a set of one or more single network slice selection assistance information (S-NSSAI) to an access and mobility management function (AMF), receives a response to the registration request message indicating that the request to register to the set of one or more S-NSSAI is rejected, and locally stores the set of one or more S-NSSAI in a rejected NSSAI list.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] Inventors: Vinay Mysore Viswanath, Vijay Venkataraman and Vivek G. Gupta <Priority Claim / Incorporation by Reference> This application claims priority to U.S. Provisional Patent Application No. 63 / 263,412, entitled “Enhancements for User Equipment Network Slice Management,” filed November 2, 2021, which is incorporated by reference in its entirety. [Background technology]

[0002] A user equipment (UE) may connect to a network that deploys multiple network slices. In general, a network slice refers to an end-to-end logical network configured to provide a particular service and / or having particular network characteristics. Each of the network slices may be isolated from each other but may operate on a shared network infrastructure. Thus, each of the network slices may share network resources but facilitate different functions. Summary of the Invention

[0003] Some example embodiments relate to a method performed by a user equipment (UE), the method including: sending a registration request message to a network, the registration request message including a request to register to a set of one or more Single Network Slice Selection Assistance Information (S-NSSAI), receiving a response to the registration request message, the response indicating that the request to register to the set of the one or more S-NSSAIs is rejected, and storing the set of the one or more S-NSSAIs in a rejected NSSAI list locally at the UE.

[0004] Another example embodiment relates to a method performed by a user equipment (UE), the method including: registering with a first public land mobile network (PLMN), establishing a packet data unit (PDU) session on a first single network slice selection assistance information (S-NSSAI), the first S-NSSAI corresponding to the PLMN, registering with a second PLMN, receiving an authorized NSSAI corresponding to the second PLMN, the authorized NSSAI including a second S-NSSAI, the first S-NSSAI being mapped to the second S-NSSAI, and updating an S-NSSAI associated with the PDU session from the first S-NSSAI to the second S-NSSAI.

[0005] Yet a further exemplary embodiment relates to a method performed by a user equipment (UE), the method including: registering with a first public land mobile network (PLMN), establishing a packet data unit (PDU) session on a first single network slice selection assistance information (S-NSSAI), where the first S-NSSAI corresponds to a VPLMN, registering with a home PLMN (HPLMN), receiving an authorized NSSAI corresponding to the HPLMN, where the authorized NSSAI does not include an S-NSSAI that matches the first S-NSSAI, and releasing the PDU session unless a predetermined condition is met.

[0006] An additional example embodiment relates to a method performed by a user equipment (UE), the method including registering with a Home Public Land Mobile Network (HPLMN), receiving an allowed Network Slice Selection Assistance Information (NSSAI) for the HPLMN, receiving a TAI list including a Tracking Area Identity (TAI) belonging to the HPLMN, receiving a Configuration Update Command (CUC) including an updated TAI list including a TAI belonging to an Equivalent PLMN (EPLMN), and storing the allowed NSSAI in an allowed NSSAI list for the EPLMN. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 illustrates an exemplary network arrangement, in accordance with various exemplary embodiments.

[0008] [Diagram 2] FIG. 1 illustrates an example network architecture in accordance with various exemplary embodiments.

[0009] [Diagram 3] FIG. 1 illustrates an exemplary user equipment (UE), according to various exemplary embodiments.

[0010] [Figure 4] 1 illustrates an exemplary base station in accordance with various exemplary embodiments.

[0011] [Diagram 5] 1 illustrates a signaling diagram for UE initiated allowed network slice selection assistance information (NSSAI) modification in accordance with various exemplary embodiments.

[0012] [Figure 6] 1 illustrates a signaling diagram of an allowed NSSAI modification initiated by a UE, in accordance with various exemplary embodiments.

[0013] [Figure 7] 1 illustrates a signaling diagram for S-NSSAI rejection, according to various exemplary embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The exemplary embodiments can be further understood by reference to the following description and the associated drawings, in which like elements are labeled with the same reference numerals. The exemplary embodiments introduce various enhancements for network slicing. In one aspect, the exemplary embodiments relate to network slice access. In another aspect, the exemplary embodiments relate to how a user equipment (UE) manages a rejected network slice selection assistance information (NSSAI). In a further aspect, the exemplary embodiments relate to NSSAI mapping. In another aspect, the exemplary embodiments relate to how a UE manages an allowed NSSAI for an equivalent public land mobile network (EPLMN). Each of these exemplary aspects is described in detail below.

[0015] The exemplary embodiments are described with respect to a UE. However, the use of the term "UE" is for illustrative purposes only. The exemplary embodiments may be utilized with any electronic component capable of establishing a connection with a network and configured with hardware, software, and / or firmware for exchanging information and data with the network. Accordingly, a UE as described herein is used to represent any suitable electronic component.

[0016] Exemplary embodiments are also described with respect to a fifth generation (5G) network that supports network slicing. In general, network slicing refers to a network architecture in which multiple end-to-end logical networks operate on a shared physical network infrastructure. Each of the network slices may be configured to provide a particular set of capabilities and / or characteristics. Thus, the physical infrastructure of a 5G network may be sliced ​​into multiple virtual networks, each of which is configured for a different purpose. Throughout this description, references to network slices may refer to any type of end-to-end logical network that is configured to serve a particular purpose and is implemented on the 5G physical infrastructure.

[0017] Those skilled in the art will appreciate that 5G may support a variety of different use cases, such as enhanced Mobile BroadBand (eMBB), enhanced Machine Type Communication (eMTC), high-performance machine-type (HMTC), Industrial Internet of Things (IIoT), massive Internet of things (MIoT), ultra-reliable low-latency communication (URLLC), vehicle-to-everything (V2X), and the like. Each type of use case may relate to a variety of different types of applications and / or services. A network slice may be characterized by a type of use case, a type of application and / or service, or an entity that provides an application and / or service through the network slice. In addition, an operator may deploy multiple network slices for different vertical applications, and operator-specific applications may use different network slices. However, any examples in this description that characterize a network slice in a specific manner are provided for illustrative purposes only. Throughout this description, references to network slices are configured to serve a particular purpose and may represent any type of end-to-end logical network implemented in the 5G physical infrastructure.

[0018] A network slice may be identified by a Single Network Slice Selection Assistance Information (S-NSSAI). Each instance of the S-NSSAI may be associated with a Public Land Mobile Network (PLMN) and may include a Slice Service Type (SST) and a Slice Descriptor (SD). The SST may identify the expected behavior of the corresponding network slice in terms of services, features, and characteristics. Those skilled in the art will appreciate that the SST may be associated with standardized SST values. The SD may identify any one or more entities associated with the network slice. For example, the SD may indicate an owner or entity (e.g., a carrier) that manages the network slice and / or an entity (e.g., a third party, an entity providing an application / service, etc.) that provides an application / service over the network slice. In some embodiments, the same entity may own the network slice and provide a service (e.g., a carrier service). Throughout this description, the S-NSSAI refers to a single network slice, and the terms "NSSAI" or "S-NSSAI" may be used interchangeably to refer to one or more network slices.

[0019] A UE may be configured to perform any of a wide variety of different tasks. Thus, a UE may be configured to use one or more network slices. To provide an example, a UE may use a first network slice for one or more carrier services (e.g., voice, Multimedia Messaging Service (MMS), Internet, etc.) and a second, different network slice for third party services. However, the configured purpose of the network slices is beyond the scope of the example embodiments. The example embodiments are not limited to any particular type of network slice.

[0020] Examples described herein may refer to the terms “Allowed NSSAI,” “Configured NSSAI,” “Requested NSSAI,” and “Rejected NSSAI.” Before describing example enhancements, a brief description of each of these terms and how they may relate to one another is provided below.

[0021] Those skilled in the art will appreciate that the term "authorized NSSAI" refers to a network-provided S-NSSAI that a UE may utilize in a serving PLMN for a particular registration area. As described in more detail below, the authorized NSSAI may be provided to the UE by the network during a registration procedure (e.g., a mobility registration update procedure or any other suitable type of registration procedure). Due to the relationship between registration and authorized NSSAI, in some embodiments, the term "registered network slice" may be used interchangeably with authorized NSSAI to refer to the same concept.

[0022] To keep track of the allowed NSSAIs, the UE may operate an allowed NSSAI list stored locally at the UE or may utilize any other suitable mechanism. The number of network slices that may be considered as allowed NSSAIs for the UE may be limited to a predetermined maximum number of allowed NSSAIs. For example, the 3GPP specification limits the maximum number of allowed NSSAIs to a length of eight S-NSSAIs. However, the exemplary embodiments are not limited to the maximum number of allowed NSSAIs being a length of eight S-NSSAIs and may apply to any suitable maximum number of allowed NSSAIs. In some scenarios, when the S-NSSAI is stored locally as an allowed NSSAI, the UE may attempt to establish a packet data unit (PDU) session on the S-NSSAI. However, when the S-NSSAI is not considered as part of the allowed NSSAIs, the UE may ignore the upper layer request for the S-NSSAI and the PDU session establishment on the network slice may not be initiated by the UE.

[0023] Those skilled in the art will appreciate that the term "configured NSSAI" refers to an S-NSSAI that is provisioned in the UE and applicable to one or more PLMNs. To keep track of the configured NSSAI, the UE may operate a configured NSSAI list stored locally in the UE, or may utilize any other suitable mechanism. When the network slice is stored locally as a configured NSSAI, the value of the S-NSSAI is known to the UE. When the network slice is not stored locally as a configured NSSAI, the UE may not know the value of the S-NSSAI. The number of configured NSSAIs may be limited to a predetermined maximum number of configured NSSAIs. For example, the 3GPP specification limits the maximum number of configured NSSAIs to a length of 16 S-NSSAIs. However, the exemplary embodiments are not limited to the maximum number of configured NSSAIs being a length of 16 S-NSSAIs, and may apply to any suitable number. In some embodiments, the term "subscribed network slice" may be used interchangeably with configured NSSAI to refer to the same concept.

[0024] During operation, the number of configured NSSAIs stored locally at the UE may be greater than the number of permitted NSSAIs stored locally at the UE. Thus, there may be one or more S-NSSAIs that may be considered by the UE to be configured NSSAIs but not part of the permitted NSSAIs. For example, S-NSSAI-A may be part of the configured NSSAI list stored locally at the UE but not part of the permitted NSSAI list stored locally at the UE. In this type of configuration, the UE does not initiate a PDU session establishment on S-NSSAI-A because S-NSSAI-A is not part of the permitted NSSAI list. Throughout this description, any reference to "S-NSSAI-A" is provided merely to distinguish one network slice from other network slices and is not intended to limit the example embodiments in any way.

[0025] Those skilled in the art will understand that the term "requested NSSAI" refers to an NSSAI provided by the UE to the network during the registration procedure. The network may then determine whether the UE is authorized to register to each requested S-NSSAI. For example, the UE may store the S-NSSAI-A as part of the configured NSSAI. The UE may then send a registration request message to the network indicating that the UE wishes to register to one or more network slices, such as the S-NSSAI-A. In response, the network may indicate that the requested S-NSSAI is an authorized NSSAI. The UE may then store the S-NSSAI-A in the authorized NSSAI list.

[0026] Alternatively, in response to the requested NSSAI, the network may indicate that the request for S-NSSAI-A is rejected. To provide some examples, the rejection may be due to a lack of available resources in the registration area or due to a failure to authenticate the UE's access to a particular network slice. The UE may then consider the S-NSSAI-A to be a "rejected NSSAI". To keep track of the rejected NSSAIs, the UE may operate a rejected NSSAI list stored locally at the UE or may utilize any other suitable mechanism. In some scenarios, the UE may be configured to omit or ignore the rejected NSSAI during other operations and / or procedures. For example, under some conditions, the UE may not attempt to register to a network slice that is stored locally as part of the rejected NSSAI.

[0027] The above examples provide a general overview of the relationships between the terms "Allowed NSSAI," "Configured NSSAI," "Requested NSSAI," and "Rejected NSSAI." These examples are not intended to limit the scope of these terms or exemplary embodiments in any way.

[0028] Some of the example embodiments are described with respect to a scenario in which a UE desires to access a network slice that is not part of the authorized NSSAI. To provide an example, consider a scenario in which a UE is deployed in a PLMN and remains stationary for a relatively long duration. While deployed, an application may be downloaded onto the UE that requires connectivity to S-NSSAI-A. However, S-NSSAI-A is not part of the authorized NSSAI. Due to the static behavior of the UE, the UE may not be triggered to initiate a registration procedure. As a result, the UE may not be able to gain access to a desired network slice (e.g., S-NSSAI-A) for an unreasonable amount of time.

[0029] Under conventional circumstances, such as the example given above, the UE may not trigger a change to the authorized NSSAI even though the desired network slice is not part of the authorized NSSAI, and the UE may not gain access to the desired network slice for an unreasonable amount of time. As described in more detail below, in one aspect, the exemplary embodiments introduce techniques that enable the UE to initiate modifications to the authorized NSSAI. These techniques may enable the UE to quickly gain access to the desired network slice even when the network slice is not part of the authorized NSSAI.

[0030] In another aspect, the exemplary embodiment relates to managing a rejected NSSAI stored locally at a UE. Typically, a UE does not register to a network slice that is stored in a rejected NSSAI list. There are various conditions that may trigger the UE to remove a network slice from the rejected NSSAI list. However, it has been identified that under conventional circumstances, there may be scenarios in which a UE should be able to access a particular network slice that was previously rejected, but nothing has triggered the UE to remove the network slice from the rejected NSSAI list. As a result, the UE may prevent itself from registering to a network slice that is actually available to the UE and that the UE is allowed to use. As described in more detail below, the exemplary embodiment introduces a technique that enables the UE to remove an entry from a rejected NSSAI stored locally at the UE.

[0031] In a further aspect, the exemplary embodiment relates to NSSAI mapping. Different PLMNs may interpret the same S-NSSAI value in different ways. It has been identified that the UE does not properly consider the mapping of the S-NSSAI during UE mobility from a Home PLMN (HPLMN) to a Visited PLMN (VPLMN) or vice versa. This may cause inconsistencies between the UE and the network regarding how the S-NSSAI value is interpreted, which may lead to unpredictable behavior and poor user experience by inadvertently deleting PDU sessions. Therefore, the S-NSSAI value may need to be mapped across PLMNs to ensure that the S-NSSAI value is properly interpreted. As described in more detail below, the exemplary embodiment introduces techniques configured to improve how a UE manages S-NSSAI mapping across different PLMNs.

[0032] In another aspect, an exemplary embodiment relates to a UE managing an authorized NSSAI for an EPLMN. It has been identified that the UE does not properly consider Tracking Area Identifiers (TAIs) belonging to different PLMNs when managing the authorized NSSAI. As described in more detail below, the exemplary embodiment introduces techniques configured to improve how the UE manages the authorized NSSAI for an EPLMN. Each of the exemplary enhancements described herein may be used independently of one another, with currently implemented network slicing mechanisms, future implementations of network slicing mechanisms, or independently of other network slicing mechanisms. Specific examples of each of these exemplary enhancements are described in detail below.

[0033] 1 illustrates an exemplary network deployment 100 in accordance with various exemplary embodiments. The exemplary network deployment 100 includes a UE 110. Those skilled in the art will appreciate that the UE 110 may be any type of electronic component configured to communicate over a network, such as, for example, a mobile phone, a tablet computer, a desktop computer, a smartphone, a phablet, an embedded device, a wearable, an Internet of Things (IoT) device, etc. It will also be appreciated that an actual network deployment may include any number of UEs being used by any number of users. Thus, the example of a single UE 110 is for illustrative purposes only.

[0034] The UE 110 may be configured to communicate with one or more networks. In the example network configuration 100, the network with which the UE 110 may communicate wirelessly is a 5G NR Radio Access Network (RAN) 120. However, the UE 110 may also communicate with other types of networks (e.g., 5G Cloud RAN, Next Generation RAN (NG-RAN), Long Term Evolution (LTE) RAN, legacy cellular networks, Wireless Local Area Network (WLAN), etc.), and the UE 110 may also communicate with a network by a wired connection. For an example embodiment, the UE 110 may establish a connection with the 5G NR RAN 120. Thus, the UE 110 may have a 5G NR chipset to communicate with the 5G NR RAN 120.

[0035] The 5G NR RAN 120 may be part of a cellular network that may be deployed by a network carrier (e.g., Verizon, AT&T, T-Mobile, etc.). The 5G NR RAN 120 may include, for example, nodes, cells, or base stations (e.g., NodeB, eNodeB, HeNB, eNBS, gNB, gNodeB, macro cell, micro cell, small cell, femto cell, etc.) configured to transmit and receive traffic from UEs equipped with appropriate cellular chipsets.

[0036] Those skilled in the art will appreciate that any association procedure may be performed for the UE 110 to connect to the 5G NR-RAN 120. For example, as described above, the 5G NR-RAN 120 may be associated with a particular cellular provider for which the UE 110 and / or the user of the UE 110 has contract information and credentials (e.g., stored on a SIM card). Upon detecting the presence of the 5G NR-RAN 120, the UE 110 may transmit corresponding authentication information to associate with the 5G NR-RAN 120. More specifically, the UE 110 may associate with a particular base station, e.g., a next generation Node B (gNB) 120A.

[0037] The network deployment 100 also includes a cellular core network 130, an Internet 140, an IP Multimedia Subsystem (IMS) 150, and a network services backbone 160. The cellular core network 130 may be considered as a set of interconnected components that manage the operation and traffic of the cellular network. It may include an Evolved Packet Core (EPC) and / or a 5th Generation Core (5G Core, 5GC). The cellular core network 130 also manages the traffic flowing between the cellular network and the Internet 140. The IMS 150 may generally be described as an architecture for delivering multimedia services to the UE 110 using IP protocols. The IMS 150 may communicate with the cellular core network 130 and the Internet 140 to provide the multimedia services to the UE 110. The network services backbone 160 communicates with the Internet 140 and the cellular core network 130 either directly or indirectly. The network services backbone 160 may generally be described as a set of components (e.g., servers, network storage arrangements, etc.) that implement a suite of services that may be used to extend the functionality of the UE 110 in communicating with various networks.

[0038] 2 illustrates an example network architecture 200 in accordance with various example embodiments. The following description provides a general overview of the various components of the example architecture 200. The specific operations performed by the components for example embodiments are described in more detail following the description of the architecture 200.

[0039] Those skilled in the art will appreciate that the components of the example architecture 200 may reside in various physical and / or virtual locations relative to the network deployment 100 of Figure 1. These locations may include within an access network (e.g., RAN 120), within a core network 130, as separate components outside of the locations discussed with respect to Figure 1, etc.

[0040] In FIG. 2, the various components are shown as being connected via connections (e.g., N1, N2, N11) labeled Nx. Those skilled in the art will appreciate that each of these connections (or interfaces) is defined in the 3GPP specifications. The example architecture 200 uses these connections in the manner in which they are defined in the 3GPP specifications. Additionally, although these interfaces are referred to as connections throughout this description, it should be understood that these interfaces need not be direct wired or wireless connections, e.g., the interfaces may communicate through intervening hardware and / or software components. To provide an example, the UE 110 may exchange signals over the air with the gNB 120A. However, in the architecture 200, the UE 110 is shown as having a connection to the AMF 205. This connection or interface is not a direct communication link between the UE 110 and the AMF 205, but is a connection facilitated by intervening hardware and software components. Thus, throughout this description, the terms "connection" and "interface" may be used interchangeably to describe the Nx interfaces between the various components.

[0041] The architecture 200 includes a UE 110 and a 5G NR RAN 120. The UE 110 and the 5G NR RAN 120 are connected to an Access and Mobility Management Function (AMF) 205. The AMF 205 is generally responsible for connectivity and mobility management in the 5G NR RAN 120. Those skilled in the art will appreciate that the AMF 205 is a control plane function and may perform operations related to registration management and connectivity management. For example, the AMF 205 may perform operations related to registration management between the UE 110 and the core network 130. The exemplary embodiment is not limited to an AMF performing the above referenced operations. Those skilled in the art will appreciate the various different types of operations that the AMF may perform. Furthermore, reference to a single AMF 205 is merely for illustrative purposes and an actual network deployment may include any suitable number of AMFs.

[0042] The AMF 205 is connected to a Session Management Function (SMF) 210. The SMF 210 may perform operations related to session management, such as session establishment, session release, IP address allocation, policy and QoS enforcement, etc. In operation, the UE 110 and the SMF 210 may exchange PDU session establishment requests and PDU session establishment responses. The exemplary embodiments are not limited to the AMF performing the above referenced operations. Those skilled in the art will appreciate the various different types of operations that the SMF may perform. Furthermore, reference to a single SMF 210 is for illustrative purposes only and an actual network deployment may include any suitable number of SMFs.

[0043] Figure 3 illustrates an exemplary UE 110, in accordance with various exemplary embodiments. The UE 110 will be described with respect to the network arrangement 100 of Figure 1. The UE 110 may include a processor 305, a memory arrangement 310, a display device 315, an input / output (I / O) device 320, a transceiver 325, and other components 330. The other components 330 may include, for example, audio input devices, audio output devices, a power source, a data acquisition device, ports for electrically connecting the UE 110 to other electronic devices, and the like.

[0044] The processor 305 may be configured to execute multiple engines of the UE 110. For example, the engines may include an allowed NSSAI engine 335, a rejected NSSAI engine 340, and an NSSAI mapping engine 345. The allowed NSSAI engine 335 may perform various operations related to managing the allowed NSSAI stored locally at the UE 110, including, but not limited to, initiating modifications to the allowed NSSAI and managing the allowed NSSAI for the EPLMN. The rejected NSSAI engine 340 may perform various operations related to managing the rejected NSSAI stored locally at the UE 110. The NSSAI mapping engine 345 may perform various operations related to tracking NSSAI mapping across different PLMNs.

[0045] The above engines 335-345, which are applications (e.g., programs) executed by the processor 305, are each provided for illustrative purposes only. The functionality associated with the engines 335-345 may also be represented as separate built-in components of the UE 110, or may be modular components coupled to the UE 110, such as integrated circuits with or without firmware. For example, an integrated circuit may include input circuitry for receiving signals and processing circuitry for processing signals and other information. The engines may also be implemented as one application or separate applications. Additionally, in some UEs, the functionality described for the processor 305 is split between two or more processors, such as a baseband processor and an application processor. The illustrative embodiments may be implemented in any of these or other configurations of a UE.

[0046] The memory arrangement 310 may be a hardware component configured to store data related to operations performed by the UE 110. The display device 315 may be a hardware component configured to show data to a user, and the I / O device 320 may be a hardware component that allows a user to provide input. The display device 315 and the I / O device 320 may be separate components or may be integrated, such as a touch screen. The transceiver 325 may be a hardware component configured to establish a connection with the 5G NR-RAN 120, an LTE-RAN (not shown), a legacy RAN (not shown), a WLAN (not shown), etc. Thus, the transceiver 325 may operate at a variety of different frequencies or channels (e.g., a set of contiguous frequencies).

[0047] 4 illustrates an exemplary base station 400 in accordance with various exemplary embodiments. The base station 400 may represent a gNB 120A or any other access node with which a UE 110 may establish a connection and manage network operations.

[0048] The base station 400 may include a processor 405, a memory unit 410, input / output (I / O) devices 415, a transceiver 420, and other components 425. The other components 425 may include, for example, audio input devices, audio output devices, a battery, data acquisition devices, ports for electrically connecting the base station 400 to other electronic devices, etc.

[0049] The processor 405 may be configured to execute multiple engines of the base station 400. For example, the engines may include a network slicing engine 430. The network slicing engine 430 may perform various operations related to enabling network slicing, including, but not limited to, facilitating communications between the UE 110 and various network components (e.g., the AMF 205, the SMF 210, etc.).

[0050] The engine 430 described above as an application (e.g., program) executed by the processor 405 is merely exemplary. The functionality associated with the engine 430 may also be represented as a separate, integrated component of the base station 400, or may be a modular component coupled to the base station 400, such as an integrated circuit with or without firmware. For example, the integrated circuit may include input circuitry for receiving signals and processing circuitry for processing signals and other information. Additionally, in some base stations, the functionality described for the processor 305 is divided among multiple processors (e.g., baseband processor, application processor, etc.). The exemplary embodiments may be implemented in any of these or other configurations of a base station.

[0051] The memory 410 may be a hardware component configured to store data related to operations performed by the base station 400. The I / O device 415 may be a hardware component or port that allows a user to interact with the base station 400. The transceiver 420 may be a hardware component configured to exchange data with the UE 110 and any other UEs in the system 100. The transceiver 420 may operate at a variety of different frequencies or channels (e.g., a set of contiguous frequencies). Thus, the transceiver 420 may include one or more components (e.g., radios) to enable data exchange with various networks and UEs.

[0052] During operation, for any of a variety of different reasons, UE 110 may desire to gain access to a network slice that is not part of the authorized NSSAI. To give some examples, an application may be installed on UE 110 or a particular feature may be activated by higher layers of UE 110 that requires connectivity to a particular network slice. Under conventional circumstances, UE 110 may not be able to gain access to a desired network slice for an unreasonable amount of time if the desired network slice is not part of the authorized NSSAI.

[0053] In one aspect, the example embodiment introduces techniques that allow the UE to initiate modifications to the allowed NSSAI. Signaling diagram 500 illustrates an example of a UE-initiated authorized NSSAI modification where the desired network slice is part of the configured NSSAI but not part of the allowed NSSAI. Signaling diagram 600 illustrates an example of a UE-initiated authorized NSSAI modification where the desired network slice is not part of the configured or allowed NSSAI. These techniques may enable UE 110 to quickly gain access to a desired network slice even when the network slice is not part of the allowed NSSAI.

[0054] 5 illustrates a signaling diagram 500 of UE initiated allowed NSSAI modification in accordance with various exemplary embodiments. Signaling diagram 500 includes UE 110, AMF 205, and SMF 210. In some examples, references may be made to an application processor and a baseband processor when describing operations performed by UE 110. However, these examples are not intended to limit the exemplary embodiments in any way. UE 110 may perform the operations described herein using any suitable combination of hardware, software, and / or firmware.

[0055] At 505, UE 110 identifies that a desired network slice (e.g., S-NSSAI-A) is part of a configured NSSAI but not part of an authorized NSSAI. To provide an example, consider a scenario in which UE 110 is deployed in a PLMN and has already been provided with an authorized NSSAI by the network. UE 110 is provisioned with S-NSSAI-A and stores it locally as a configured NSSAI. However, at this time, S-NSSAI-A is not part of the authorized NSSAI. An application may then be installed on UE 110 that maps to S-NSSAI-A. However, the example embodiments are not limited to this type of scenario and UE 110 may desire to gain access to a desired network slice for any suitable reason.

[0056] Continuing with the example provided above, in some embodiments, the application processor may determine that a new application has been installed that requires connectivity to the S-NSSAI-A. The application processor may then send a request to the baseband processor for access to the desired S-NSSAI-A. The baseband processor may detect that the UE 110 has subscribed to the S-NSSAI-A but is not registered in the S-NSSAI-A.

[0057] At 510, the UE 110 triggers a mobility registration update procedure to register with the desired network slice. As described in more detail below with respect to 515, the UE 110 may send a registration request message including a requested NSSAI with the desired network slice (e.g., S-NSSAI-A) to the AMF 205 as part of the mobility registration update procedure.

[0058] The one or more trigger conditions for the mobility registration update procedure at 510 are configured to balance the functionality and / or user experience of the network slice in which the UE 110 is already registered and the desired network slice. As indicated above, one example trigger condition for the mobility registration update procedure may include a higher layer (e.g., application processor) request for an NSSAI that is not present in the locally stored allowed NSSAIs but includes one or more S-NSSAIs included as part of the locally stored configured NSSAIs. In other words, the mobility registration update procedure may be triggered in response to detecting that the UE 110 is subscribed to but not registered in one or more S-NSSAIs corresponding to applications running on the UE 110.

[0059] The one or more trigger conditions may also include conditions related to currently stored permitted NSSAIs. One exemplary trigger condition may be a number of stored permitted NSSAIs being less than a predetermined maximum number of permitted NSSAIs. Another exemplary trigger condition may be an permitted NSSAI list that comprises an S-NSSAI that does not include an S-NSSAI corresponding to a new application or feature as indicated in the higher layer request for the NSSAI. When the currently registered network slice does not match the NSSAI requested by the higher layer, this may indicate that the UE 110 maintains a registration to an S-NSSAI that is unlikely to be utilized by the UE 110.

[0060] The one or more trigger conditions may also include a condition related to a 5G mobility management (5GMM) mode of operation of the UE 110. One skilled in the art will appreciate that the UE 110 may be configured in one of a number of different 5GMM modes of operation. When the UE 110 is in a 5GMM-CONNECTED mode, the UE 110 may not trigger a mobility registration update procedure to register to a desired network slice. However, when the UE 110 is in a 5GMM-IDLE mode, the UE 110 may trigger a registration procedure to register the UE 110 to a desired network slice.

[0061] At 515, the UE 110 sends a registration request message to the AMF 205. The registration request message may include a requested NSSAI (e.g., S-NSSAI-A) with the desired network slice. At 520, the AMF 205 sends a registration accept message to the UE 110. The registration accept message may include an allowed NSSAI with the desired network slice S-NSSAI-A. The UE 110 is now registered to the S-NSSAI-A and may establish a PDU session on this network slice. Thus, at 525, the UE 110 sends a PDU session establishment request to the SMF 210 to establish a PDU session on the network slice S-NSSAI-A.

[0062] Continuing with the example described above, in some embodiments, the baseband processor may send the updated allowed NSSAI list to the application processor, which may then detect that S-NSSAI-A is available for the corresponding application and send a request to the baseband processor to establish a data call with a remote server over S-NSSAI-A.

[0063] At 530, SMF 210 sends a registration accept message to UE 110 indicating that a PDU session has been established on network slice S-NSSAI-A. However, the above referenced PDU session establishment procedure is provided for illustrative purposes only. The example enhancements described in signaling diagram 500 are directed to modifying the allowed NSSAI, and what happens after UE 110 is registered on the desired network slice is beyond the scope of the example embodiments.

[0064] 6 illustrates a signaling diagram 600 of UE initiated allowed NSSAI modification in accordance with various exemplary embodiments. The signaling diagram 600 includes the UE 110, the AMF 205, and the SMF 210. In some examples, references may be made to an application processor and a baseband processor when describing operations performed by the UE 110. However, these examples are not intended to limit the exemplary embodiments in any way. The UE 110 may perform the operations described herein using any suitable combination of hardware, software, and / or firmware.

[0065] At 605, UE 110 identifies that the desired network slice (e.g., S-NSSAI-A) is not part of a configured NSSAI. To provide an example, consider a scenario in which UE 110 is deployed in a PLMN, provisioned with a configured NSSAI, and provided with an NSSAI authorized by the network. However, UE 110 is not provisioned with S-NSSAI-A. Then, an application that maps to S-NSSAI-A is installed on UE 110, but S-NSSAI-A is not part of the configured NSSAI for UE 110. Example embodiments are not limited to this type of scenario, and UE 110 may desire to gain access to a desired network slice for any suitable reason.

[0066] Continuing with the example described above, in some embodiments, the application processor may determine that a new application has been installed that requires connectivity to the S-NSSAI-A. The application processor may then send a request to the baseband processor for access to the desired S-NSSAI-A. The baseband processor may then detect that the UE 110 is not subscribed to the S-NSSAI-A.

[0067] At 610, the AMF 205 transmits the configured NSSAI comprising the desired network slice (e.g., S-NSSAI-A) to the UE 110. The AMF 205 may transmit the configured NSSAI to the UE 110 in response to an explicit request by the UE 110 or in response to other conditions experienced by the UE 110 and / or the network. In one example, the UE 110 performs an initial registration with an NR network to receive the configured NSSAI. In another example, the UE receives a newly configured NSSAI due to a handover from an LTE radio access technology (RAT) to a 5G NR RAT. In another example, in response to the user subscribing to the desired network slice, the network sends the new configured NSSAI in a registration accept message or a configuration update command (CUC). However, the example embodiments are not limited to these examples, and the UE 110 may receive the configured NSSAI in any suitable manner.

[0068] At 615, the UE 110 identifies that the desired network slice (e.g., S-NSSAI-A) is part of a configured NSSAI but not part of an allowed NSSAI. At 620, the UE 110 triggers a mobility registration update procedure to register with the desired network slice. As described in more detail below with respect to 625, the UE 110 may send a registration request message to the AMF 205 including the requested NSSAI with the desired network slice (e.g., S-NSSAI-A) as part of the registration procedure.

[0069] The one or more trigger conditions for the mobility registration update procedure at 620 are configured to balance the functionality and / or user experience of the currently registered network slice and the desired network slice. As indicated above, one example trigger condition for the mobility registration update procedure may include receiving an S-NSSAI in a configured NSSAI from a network previously requested by a higher layer (e.g., an application processor). In other words, the mobility registration update procedure may be triggered in response to UE 110 detecting that it is currently subscribed to a network slice previously requested by a higher layer.

[0070] The one or more trigger conditions may also include conditions related to currently stored permitted NSSAIs. One exemplary trigger condition may be the number of stored permitted NSSAIs being less than a predetermined maximum number of permitted NSSAIs. Another exemplary trigger condition may be the permitted NSSAI list comprising the S-NSSAI not included in the higher layer request for the NSSAI.

[0071] The one or more trigger conditions may also include a condition related to a 5GMM operating mode of the UE 110. When the UE 110 is in a 5GMM-CONNECTED mode, the UE 110 may not trigger a mobility registration update procedure to register to a desired network slice. However, when the UE 110 is in a 5GMM-IDLE mode, the UE 110 may trigger a registration procedure to register the UE 110 to a desired network slice.

[0072] At 625, the UE 110 sends a registration request message to the AMF 205. The registration request message may include a requested NSSAI (e.g., S-NSSAI-A) with the desired network slice. At 630, the AMF 205 sends a registration accept message to the UE 110. The registration accept message may include an allowed NSSAI with the desired network slice S-NSSAI-A. The UE 110 is now registered to the S-NSSAI-A and may establish a PDU session on this network slice. Thus, at 635, the UE 110 sends a PDU session establishment request to the SMF 210 to establish the PDU session network slice S-NSSAI.

[0073] Continuing with the example described above, in some embodiments, the baseband processor may send the updated allowed NSSAI list to the application processor, which may then detect that S-NSSAI-A is available for the corresponding application and send a request to the baseband processor to establish a data call with a remote server over S-NSSAI-A.

[0074] At 640, SMF 210 sends a REGISTER ACCEPT message to UE 110 indicating that a PDU session has been established on network slice S-NSSAI-A. However, the above referenced PDU session establishment procedure is provided for illustrative purposes only. The example enhancements described in signaling diagram 600 are directed to modifying the allowed NSSAI, and what happens after UE 110 is registered on the desired network slice is beyond the scope of the example embodiments.

[0075] As mentioned above, one of the trigger conditions for UE initiated allowed NSSAI treatment may be 5GMM-IDLE mode. For example, UE 110 may initiate a mobility registration update procedure in 5GMM-IDLE mode to register for a new list of NSSAIs based on i) a change in network slice requested by higher layers due to policy and / or ii) an updated configured NSSAI list received by UE 110 as part of a configuration update command (CUC) or registration accept message.

[0076] In some embodiments, for an initial registration accepted by the network, if the registration accept message includes a network slicing indication IE with a network slicing subscription change indication set to "network slicing subscription change" or includes a configured NSSAI IE with a new configured NSSAI for the current PLMN, UE 110 may wait until entering 5GMM-IDLE mode, and then UE 110 may initiate a mobility registration update procedure to register with a new set of NSSAI based on the new configured NSSAI.

[0077] In some embodiments, for a mobility registration update accepted by the network, if a new configured NSSAI for the current PLMN is included, AMF 205 may also include a mapped S-NSSAI for the configured NSSAI for the current PLMN in the registration accept message, if available, and UE 110 may wait until entering 5GMM-IDLE mode, and UE 110 may initiate a registration procedure for the mobility registration update to register with a new set of NSSAI based on the new configured NSSAI.

[0078] In some embodiments, the trigger conditions for the mobility registration update procedure may also include the status of a 5G system (5GS) mobility management timer. In this example, the timer is called "T3540" defined in various 3GPP specifications. The exemplary embodiment introduces a technique to utilize this timer for an exemplary UE-initiated allowed NSSAI modification procedure. However, the exemplary embodiment is not limited to the T3540 timer and may introduce a new timer for this purpose or utilize any other suitable mechanism.

[0079] In one example, if UE 110 receives a Configuration Update Command (CUC) message that does not indicate "REGISTRATION REQUEST" in the registration request bit of a configuration update indication IE, UE 110 may initiate T3540. Upon expiration of T3540 (and zero or more other trigger conditions), UE 110 may initiate a mobility registration update procedure to register with a network slice based on a new configured NSSAI. For example, within the context of signaling diagram 600, UE 110 may receive a CUC message at 610 and initiate T3540. At 620, UE 110 may trigger a mobility registration update procedure based at least in part on the expiration of T3540.

[0080] Timer T3540 may also be utilized to release the N1 Non-Access Stratum (NAS) signaling connection. In some embodiments, the start of T3540 may be triggered when i) a CUC message does not indicate "Registration Request" in the Registration Request bit of the Configuration Update Indication IE, ii) user plane resources for a PDU session are not set up, and / or iii) an emergency PDU session is not established.

[0081] After T3540 starts, UE 110 may be triggered to stop the timer and perform a specific operation. For example, upon an indication from lower layers that the access stratum connection has been released, UE 110 may stop T3540 and perform a new registration procedure. In another example, in response to an indication from lower layers that user plane resources for a PDU session have been set up, UE may stop T3540 and send user data over the user plane. In this scenario, the new registration procedure may be performed when UE 110 moves to 5GMM-IDLE mode. In another example, UE 110 may stop T3540 and locally release the N1 NAS signaling connection when UE 110 is configured with 3GPP access or receives a request from higher layers to perform emergency service fallback when establishing an emergency PDU session.

[0082] In signaling diagrams 500-600, UE 110 does not need to wait for network or mobility conditions to trigger network slice registration for a desired network slice. Instead, the exemplary embodiments provide fast access to a desired network slice by allowing UE 110 to initiate a modification to the allowed NSSAI when UE 110 desires to access a network slice that is not part of the allowed NSSAI.

[0083] In another aspect, an example embodiment relates to a UE 110 managing a rejected NSSAI. As described above, a requested network slice may be rejected by the AMF 205 during a registration procedure. For example, the AMF 205 may send a message comprising a rejection reason code in response to the requested S-NSSAI. The rejection reason code may indicate a reason for the rejection, for example, the S-NSSAI is not available in the current PLMN, the S-NSSAI is not available in the current registration area, etc.

[0084] The UE 110 may operate on a rejected NSSAI list stored locally at the UE 110. In general, the UE 110 may not register with a network slice if the S-NSSAI is stored as part of the rejected NSSAI list. For example, the UE 110 may ignore or omit an S-NSSAI requested by higher layers for subsequent operation if the S-NSSAI is part of the rejected NSSAI list.

[0085] UE 110 may not register with a network slice stored in the rejected NSSAI list until the network slice is removed from the rejected NSSAI list. Under conventional circumstances, UE 110 may not remove an S-NSSAI from the rejected NSSAI list in a timely manner. This may create a scenario in which an S-NSSAI-A was rejected by the network during the registration procedure, but then conditions change and the cause of the rejection is no longer true. In this type of scenario, UE 110 should be able to access the network slice, but since there was nothing that triggered UE 110 to remove the S-NSSAI from the rejected NSSAI list, UE 110 continues to behave as if the network slice is not available. As described in more detail below, the exemplary embodiment introduces techniques for handling rejected NSSAIs that enable UE 110 to avoid the types of scenarios described above that may occur under conventional circumstances.

[0086] FIG. 7 illustrates a signaling diagram 700 for S-NSSAI rejection according to various exemplary embodiments. Thus, the signaling diagram 700 includes the UE 110 and the AMF 205. The signaling diagram 700 is used to provide a general overview of network slice rejection and to provide a context for exemplary enhancements for managing rejected NSSAIs at the UE 110. In this example, references to PLMN_1 and S-NSSAI-A are not intended to limit the exemplary embodiments in any way. Instead, PLMN_1 is used to distinguish one PLMN from other PLMNs. Similarly, S-NSSAI-A is used to distinguish one S-NSSAI from other S-NSSAIs.

[0087] At 705, the UE 110 sends a registration request message to the AMF 205. The registration request message may include a requested NSSAI comprising at least the S-NSSAI-A.

[0088] At 710, the AMF 205 sends a response (e.g., registration accepted, registration rejected, etc.) to the registration request message that includes an indication of the rejected network slice. For example, the response may include a rejection reason code associated with the S-NSSAI-A indicating why the network did not accept the UE 110 registration request for the S-NSSAI-A. To give some examples, the rejection reason code may indicate that the S-NSSAI is not available in the current PLMN or that the S-NSSAI is not available in the current registration area. In other examples, the rejection reason code may indicate that the network slice quota has been reached. However, these examples are provided merely for illustrative purposes and the reasons why the network rejected the network slice are beyond the scope of the example embodiments.

[0089] One of the example techniques relates to a scenario in which UE 110 is registered to PLMN_1 and has a rejected NSSAI list for PLMN_1. For example, UE 110 may receive a rejected NSSAI for PLMN_1 at 710 of signaling diagram 700. UE 110 also receives a network slicing indication IE with a network slicing subscription change indication set to "network slicing subscription change" in a registration accept message or a CUC message. In response, UE 110 may be triggered to perform mobility registration on PLMN_1.

[0090] On the network side, a change to UE 110 subscription information may be detected. The change may indicate that UE 110 is now authorized to access a previously rejected network slice (e.g., S-NSSAI-A). However, under conventional circumstances, UE 110 may not be triggered to delete the rejected NSSAI list for the current PLMN (e.g., PLMN_1). In addition, there may be no direct mechanism by which the network can ask UE 110 to delete the rejected NSSAI. As a result, even though UE 110 should be able to access S-NSSAI-A because the network slice is no longer considered a rejected NSSAI on the network side, UE 110 may still not be able to access the network slice because the network slice has not been removed from the rejected NSSAI list.

[0091] The example embodiment introduces a technique whereby UE 110 deletes rejected NSSAIs (if present) when UE 110 receives an indication of a change in subscription information from the network. To provide an example, when UE 110 receives a network slicing indication IE with network slicing subscription change indication set to “network slicing subscription change” in a registration accept message or a CUC message, UE 110 may delete network slicing information for each of the PLMNs (except the current PLMN) for which UE 110 has stored slicing information, and UE 110 may also delete any rejected NSSAIs (if present).

[0092] Another example technique relates to a scenario in which UE 110 is registered to PLMN_1 and has a rejected NSSAI list for PLMN_1. For example, UE 110 may receive a rejected NSSAI for PLMN_1 at 710 of signaling diagram 700. UE 110 also performs an inter-RAT (IRAT) transition from N1 mode to S1 mode and remains in a 5GMM registered state. One skilled in the art would understand that N1 mode is a mode of UE 110 that allows access to a 5G core network via a 5G access network, and S1 mode is a mode in which UE 110 applies to both 5G system (5GS) and evolved packet system (EPS). Due to a change in user subscription, one or more network slices stored in the rejected NSSAI list for PLMN_1 are no longer considered as rejected NSSAIs by the 5GS network. In response, UE 110 performs an IRAT transition to move to N1 mode and triggers mobility registration.

[0093] On the network side, a change to UE 110 subscription information may be detected. The change may indicate that UE 110 is now authorized to access a previously rejected network slice (e.g., S-NSSAI-A). Under conventional circumstances, UE 110 may not remove the rejected NSSAI for PLMN_1 upon IRAT transition to S1 mode, and thus UE 110 may not include the rejected NSSAI upon IRAT transition to N1 mode. As a result, UE 110 may not obtain access to a network slice that was previously rejected but has now been removed from the NSSAI rejected by the network.

[0094] The example embodiment introduces a technique in which, when UE 110 performs an IRAT transition from N1 mode to S1 mode and UE 110 is not registered to the current PLMN via another access, the rejected NSSAI for the current PLMN and the rejected NSSAI for a failed or revoked network slice specific authentication and authorization (NSSAA) should be deleted by UE 110. In another technique, when UE 110 performs an IRAT transition from N1 mode to S1 mode, the rejected NSSAI for the current registration area corresponding to the access type shall be deleted by UE 110.

[0095] Another example technique relates to a scenario in which UE 110 is registered on PLMN_1 and has a rejected NSSAI list for PLMN_1. For example, UE 110 may receive the rejected NSSAI for PLMN_1 at 710 of signaling diagram 700. UE 110 also receives a CUC message with the registration requested bit in a configuration update indication IE set to “registration requested” and no other parameters. In response, UE 110 may trigger mobility registration on PLMN_1.

[0096] There may be a change to the allowed NSSAI on the network side. Under conventional circumstances, the UE 110 may not delete the rejected NSSAI for the current PLMN, and the UE 110 may be expected to delete the allowed NSSAI. However, in the above scenario, the UE 110 may not use the rejected NSSAI for subsequent registrations, which may result in the user not having access to slices despite the change to the allowed NSSAI on the network side.

[0097] The exemplary embodiment introduces a technique whereby UE 110 may delete a rejected NSSAI if UE 110 receives a CUC message with the registration requested bit in the configuration update indication IE set to "registration requested" and no other parameters.

[0098] Another example technique relates to two different scenarios. In one scenario, UE 110 is registered on PLMN_1 and has a rejected NSSAI list for PLMN_1. For example, UE 110 may receive a rejected NSSAI for PLMN_1 at 710 of signaling diagram 700. UE 110 then attempts to perform mobility registration on a different PLMN (e.g., PLMN_2) and receives a registration reject message with reason code #62 (e.g., no network slice available) and a rejected NSSAI list for PLMN_2. UE 110 remains in a 5GMM registered state.

[0099] In the above example scenario, UE 110 may be expected to delete the rejected NSSAI upon de-registration following unsuccessful registration to a new PLMN. However, under conventional circumstances, UE 110 may not delete the rejected NSSAI and may retain the rejected NSSAI for PLMN_1 and the rejected NSSAI for PLMN_2.

[0100] In a second scenario, UE 110 is registered on PLMN_1 and receives rejection reason code #62 with a rejected NSSAI that includes all rejected network slices for PLMN_1. UE 110 may not have any other network slices to register with, and UE 110 may disable N1 mode when reason code #62 is received on the current PLMN. In response, UE 110 performs an IRAT transition to S1 mode.

[0101] In the above example scenario, UE 110 is expected to delete the rejected NSSAI upon deregistration following a failed registration in the current PLMN for a 5GMM reason other than reason code # 62. However, in the above scenario, UE 110 may not delete the rejected NSSAI and may retain the rejected NSSAI for PLMN_1.

[0102] The example embodiment introduces a technique for NSSAI storage where, unless N1 mode is disabled as part of processing reason code #62, when UE 110 enters a 5GMM de-registration state following a failed registration for a 5GMM reason other than reason code #62 (e.g., no network slice available) for the current PLMN, UE 110 may delete the rejected NSSAI for the current PLMN and the rejected NSSAI for the failed or cancelled NSSAA. In another technique, when UE 110 enters a 5GMM de-registration state or a 5GMM registration state following an unsuccessful registration to a new PLMN, UE 110 may delete the rejected NSSAI for the current PLMN and the rejected NSSAI for the failed or cancelled NSSAA.

[0103] In another aspect, the exemplary embodiment relates to NSSAI mapping. NSSAIs with similar functions can have different values ​​across PLMNSs. Each S-NSSAI in the HPLMN is mapped to a corresponding S-NSSAI in the VPLMN based on the VPLMN operator's policies and configurations. It has been identified that the UE 110 may not properly consider the NSSAI mapping during UE mobility from the HPLMN to the VPLMN or vice versa. This may cause inconsistencies between the UE and the network, which may lead to unpredictable behavior (e.g., releasing PDU sessions) and poor user experience.

[0104] To provide an example, consider a scenario in which UE 110 is registered with a HPLMN, has an ongoing PDU session with S-NSSAI-A, and has no corresponding mapped S-NSSAI. UE 110 then roams to a VPLMN, registers with the VPLMN, and receives an authorized NSSAI comprising S-NSSAI-B and the corresponding mapped NSSAI S-NSSAI-A. Under conventional circumstances, UE 110 may not update the local S-NSSAI associated with the PDU session, causing an inconsistency between UE 110 and the network.

[0105] To provide another example, consider a scenario in which UE 110 is registered with a VPLMN and has an ongoing PDU session with S-NSSAI-B and a corresponding mapped S-NSSAI as S-NSSAI-A. UE 110 then returns to the HPLMN, registers with the HPLMN, and receives an authorized NSSAI with S-NSSAI-A and no corresponding mapped S-NSSAI. Under conventional circumstances, UE 110 may not update the local S-NSSAI associated with the PDU session, causing an inconsistency between UE 110 and the network.

[0106] As described in more detail below, the example embodiments introduce techniques configured to improve how a UE manages NSSAI mapping across different PLMNs. For an active PDU session at UE 110, if the allowed NSSAI includes a HPLMN S-NSSAI (e.g., a mapped S-NSSAI, if available) that matches the HPLMN S-NSSAI of the PDU session, UE 110 shall locally update the S-NSSAI associated with the PDU session to the corresponding S-NSSAI received in the allowed NSSAI. If the allowed NSSAI does not include a HPLMN S-NSSAI (e.g., a mapped S-NSSAI, if available) that matches the HPLMN S-NSSAI of the PDU session, UE 110 may perform local release of PDU sessions, except for emergency PDU sessions, if any, and except for PDU sessions established when UE 110 registered for onboarding services in a standalone non-public network (SNPN), if any.

[0107] In some embodiments, the AMF 205 may also determine which PDU sessions can no longer be supported based on the new allowed NSSAI, and either indicate in the PDU session status IE which PDU sessions are released locally on the network side or trigger the SMF 210 to initiate the release via 5G session management signaling. In some exemplary embodiments, if a network slice (e.g., S-NSSAI) is no longer available under the same AMF, the AMF indicates to the SMF which PDU session IDs corresponding to the associated S-NSSAI should be released, and the SMF releases the PDU sessions. In other exemplary embodiments, if a network slice (e.g., S-NSSAI) is no longer available at the time of AMF change (e.g., due to a registration area change), the new AMF indicates to the old AMF that the PDU sessions corresponding to the associated S-NSSAI should be released. The old AMF informs the corresponding SMF to release the indicated PDU sessions. The new AMF then modifies the PDU session status accordingly. The PDU session context is released locally in the UE after receiving the PDU session status in the Registration Accept message.

[0108] In another aspect, an example embodiment relates to a UE managing an allowed NSSAI for an equivalent PLMN (EPLMN). It has been identified that the UE does not properly consider TAIs belonging to different PLMNs when managing the allowed NSSAI. To provide an example, consider a scenario in which the UE 110 is registered with a HPLMN and has an allowed NSSAI and a TAI list including the TAIs belonging to the HPLMN. The UE 110 then receives a CUC message including an updated TAI list including TAIs belonging to a different PLMN that is an EPLMN, where there is a new allowed NSSAI. Under conventional circumstances, the UE 110 may not update the allowed NSSAI list associated with those EPLMNs.

[0109] The exemplary embodiment introduces a technique configured to improve how a UE manages allowed NSSAIs for an EPLMN. If the UE 110 receives a new TAI list in a CUC message, the UE 110 may consider the new TAI list as valid and the old TAI list as invalid. Otherwise, the UE 110 may consider the old TAI list as value. If the new TAI list includes a TAI that belongs to a different PLMN that is an EPLMN, and if the UE 110 includes an allowed locally stored NSSAI, the UE 110 may store the allowed NSSAI in each of the allowed NSSAIs associated with each of the EPLMNs. Thus, if the UE 110 with a stored allowed NSSAI receives a CUC message with a registration area that includes an updated TAI list with a different PLMN, the UE 110 may store the allowed NSSAI in each of the allowed NSSAI lists associated with each of the PLMNs.

[0110] Working Example In a first example, the method includes receiving, from a user equipment (UE), a registration request message including a requested network slice selection assistance information (NSSAI) including a single network slice selection assistance information (S-NSSAI), determining whether the UE is authorized to register on the S-NSSAI, and sending a response to the registration request message to the UE based on determining whether the UE is authorized to register on the S-NSSAI.

[0111] In a second example, the method of the first example further includes, when the UE is permitted to be registered in the S-NSSAI, registering the UE to the S-NSSAI, and the response includes a registration accept message indicating that the S-NSSAI is an permitted NSSAI.

[0112] In a third example, the method of the first example, wherein the response includes a registration reject message indicating a reason code for the rejection when the UE is not allowed to register on the S-NSSAI.

[0113] In a fourth example, the network function is configured to perform any of the methods of the first to third examples.

[0114] In a fifth example, one or more processors are configured to perform any of the methods of the first through third examples.

[0115] In a sixth example, a method includes storing, for a user equipment (UE), authorized network slice selection assistance information (NSSAI) comprising one or more single network slice selection assistance information (S-NSSAI), determining that at least one of the S-NSSAI is no longer an authorized NSSAI, and determining that there is an active protocol data unit (PDU) session active for the at least one S-NSSAI.

[0116] In a seventh example, the method of the sixth example further includes indicating to a Session Management Function (SMF) of the network that the PDU session should be released.

[0117] In an eighth example, the method of the sixth example further includes indicating to the UE that the PDU session should be released.

[0118] In a ninth example, in the method of the sixth example, illustrating includes a registration accept message including a PDU session status information element.

[0119] In a tenth example, in the method of the sixth example, the network function is a first Access and Mobility Management Function (AMF) to which the UE is currently registered, and the method further includes indicating to a second AMF to which the UE was previously registered that the PDU session is to be released.

[0120] In an eleventh example, the network function is configured to perform any of the methods of the sixth to tenth examples.

[0121] In a twelfth example, the one or more processors are configured to perform any of the methods of the sixth through tenth examples.

[0122] In a thirteenth example, actions performed by a user equipment (UE) include identifying that a single network slice selection assistance information (S-NSSAI) is a configured NSSAI rather than an allowed NSSAI, initiating a mobility registration update procedure based on one or more trigger conditions, sending a registration request message to a network, where the registration request message includes the requested NSSAI that comprises the S-NSSAI, receiving a response to the registration request message, where the response indicates that the S-NSSAI is an allowed NSSAI, and establishing a packet data unit (PDU) session on the S-NSSAI.

[0123] In a fourteenth example, the method of the thirteenth example further includes, prior to identifying, receiving a requested NSSAI list from the application processor including the S-NSSAI, the requested NSSAI list being received based on a new application, an activated feature, or a higher layer request.

[0124] In a fifteenth example, the method of the fourteenth example, wherein the one or more trigger conditions include detecting that the requested NSSAI list includes a network slice that is a configured NSSAI and is an unauthorized NSSAI.

[0125] In a sixteenth example, the method of the fourteenth example, wherein the one or more trigger conditions include detecting that the allowed NSSAI received from the network at a non-access stratum (NAS) layer does not include a network slice that is not part of a requested NSSAI list received from the application processor at the NAS layer.

[0126] In a seventeenth example, the method of the thirteenth example further includes, prior to identifying, receiving a new configured NSSAI list from the network in a configuration update command (CUC) or a registration accept message, wherein the new configured NSSAI is an S-NSSAI.

[0127] In an eighteenth example, the method of the seventeenth example, wherein the one or more trigger conditions include detecting that the updated configured NSSAI list includes a network slice that was previously requested by the upper layer.

[0128] In a 19th example, the method of the 17th example, wherein the one or more trigger conditions include detecting that the allowed NSSAI is part of a new configured NSSAI list received from the network and does not include a network slice previously requested by a higher layer.

[0129] In a twentieth example, the method of the thirteenth example, wherein the one or more trigger conditions include detecting that a stored allowed NSSAI list for a public land mobile network (PLMN) includes a number of network slices that is less than a predetermined maximum number of allowed NSSAIs for the PLMN.

[0130] In a twenty-first example, the method of the thirteenth example, wherein the one or more trigger conditions include a UE fifth generation mobility management (5GMM) idle mode of operation.

[0131] In a twenty-second example, the method of the thirteenth example further includes starting a timer configured to trigger release of the N1 non-access stratum (NSA) signaling connection if i) the configuration update command (CUC) includes a new configured NSSAI, ii) user plane resources for a packet data unit (PDU) session are not set up, iii) an emergency PDU session is not established, and iv) the CUC does not include a registration requested bit set to true in the registration requested bit of the configuration update indication information element (IE).

[0132] In a twenty-third example, the method of the twenty-second example, wherein the one or more trigger conditions include expiration of a timer.

[0133] In a twenty-fourth example, the processor is configured to perform any of the methods of the thirteenth to twenty-third examples.

[0134] In a twenty-fifth example, the user equipment is configured to perform any of the methods of the thirteenth to twenty-third examples.

[0135] It will be appreciated by those skilled in the art that the above exemplary embodiments may be implemented in any suitable hardware or software configuration or combination thereof. Exemplary hardware platforms for executing the exemplary embodiments may include, for example, Intel x86-based platforms, Windows OS, Mac platforms and MAC OS with compatible operating systems, and mobile devices with operating systems such as iOS, Android, etc. Exemplary embodiments of the above methods may be embodied as a program including lines of code stored in a non-transitory computer-readable storage medium that may be compiled and executed in a processor or microprocessor.

[0136] Although the present application describes various embodiments, each having different features in various combinations, it will be understood by those skilled in the art that any of the features of one embodiment may be combined with the features of other embodiments in a manner not specifically disclaimed or that is not functionally or logically inconsistent with the operation or described functionality of the devices of the disclosed embodiments.

[0137] It is well understood that use of personally identifiable information should comply with generally recognized privacy policies and practices that meet or exceed industry or governmental requirements for maintaining user privacy. In particular, personally identifiable information data should be managed and handled in a manner that minimizes the risk of unintended or unauthorized access or use, and the nature of permitted uses should be clearly indicated to users.

[0138] It will be apparent to those skilled in the art that various modifications may be made in the present disclosure without departing from the spirit or scope of the disclosure. Accordingly, the present disclosure is intended to cover modifications and variations of the present disclosure within the scope of the appended claims and their equivalents.

Claims

1. 1. A method performed by a user equipment (UE), comprising: sending a registration request message to the network, the registration request message including a request to register with a set of one or more Single Network Slice Selection Assistance Information (S-NSSAI); receiving a response to the registration request message, the response indicating that the request to register with the set of one or more S-NSSAIs has been denied; storing the set of one or more S-NSSAIs in a locally rejected NSSAI list at the UE; A method comprising:

2. receiving an indication of a network slice subscription change for the UE after storing the set of one or more S-NSSAIs in the rejected NSSAI list; removing the set of one or more S-NSSAIs from the rejected NSSAI list in response to the indication of the network slice subscription change; The method of claim 1 further comprising:

3. performing an Inter-Radio Access Technology (IRAT) transition from an N1 mode to an S1 mode after storing the set of one or more S-NSSAIs in the rejected NSSAI list; removing the set of one or more S-NSSAIs from the rejected NSSAI list in response to the IRAT transition; The method of claim 1 further comprising:

4. performing an Inter-Radio Access Technology (IRAT) transition from an S1 mode to an N1 mode after storing the set of one or more S-NSSAIs in the rejected NSSAI list; removing the one or more S-NSSAIs from the rejected NSSAI list in response to the IRAT transition; The method of claim 1 further comprising:

5. receiving a configuration update command (CUC) having a registration requested bit of a configuration update indication information element (IE) set to a first value after storing the set of one or more S-NSSAIs in the rejected NSSAI list; removing the set of one or more S-NSSAIs from the rejected NSSAI list in response to the CUC; The method of claim 1 further comprising:

6. The method of claim 5 , wherein the CUC does not include other parameters.

7. storing the set of one or more S-NSSAIs in the rejected NSSAI list and entering a 5th Generation Mobility Management (5GMM) registration mode after failing to register with a new Public Land Mobile Network (PLMN); removing the set of one or more S-NSSAIs from the rejected NSSAI list in response to detecting the 5GMM registration mode and detecting that the UE is not registered in a current PLMN via another access; The method of claim 1 further comprising:

8. 1. A method performed by a user equipment (UE), comprising: registering with a first public land mobile network (PLMN); establishing a packet data unit (PDU) session on a first single network slice selection assistance information (S-NSSAI), the first S-NSSAI corresponding to the PLMN; registering in a second PLMN; receiving an authorized NSSAI corresponding to the second PLMN, the authorized NSSAI including a second S-NSSAI, and the first S-NSSAI is mapped to the second S-NSSAI; updating the S-NSSAI associated with the PDU session from the first S-NSSAI to the second S-NSSAI.

9. The method of claim 8 , wherein the first PLMN is a Visited PLMN (VPLMN) and the second PLMN is a Home PLMN (HPLMN).

10. 9. The method of claim 8, wherein the first PLMN is a Home PLMN (HPLMN) and the second PLMN is a Visited PLMN (VPLMN).

11. 1. A method performed by a user equipment (UE), comprising: registering with a first public land mobile network (PLMN); establishing a packet data unit (PDU) session on a first single network slice selection assistance information (S-NSSAI), the first S-NSSAI corresponding to the VPLMN; Registering with the Home PLMN (HPLMN); receiving an authorized NSSAI corresponding to the HPLMN, the authorized NSSAI not including an S-NSSAI that matches the first S-NSSAI; Releasing the PDU session unless a predetermined condition is met; A method comprising:

12. The method of claim 11, wherein the predetermined condition includes that the PDU session is an emergency PDU session.

13. The method of claim 11 , wherein the predetermined condition includes the UE 110 being registered for onboarding services in a standalone non-public network (SNPN).

14. The method of claim 11 , wherein the first PLMN is a Visited PLMN (VPLMN) and the second PLMN is a Home PLMN (HPLMN).

15. The method of claim 11 , wherein the first PLMN is a Home PLMN (HPLMN) and the second PLMN is a Visited PLMN (VPLMN).

16. 1. A method performed by a user equipment (UE), comprising: Registering with a Home Public Land Mobile Network (HPLMN); receiving an authorized network slice selection assistance information (NSSAI) for the HPLMN; and Receiving a Tracking Area Identities (TAI) list including TAIs belonging to the HPLMN; receiving a configuration update command (CUC) including an updated TAI list including TAIs belonging to an equivalent PLMN (EPLMN); storing the authorized NSSAI in an authorized NSSAI list for the EPLMN; A method comprising:

17. receiving a rejected NSSAI for the HPLMN; and storing the rejected NSSAI in a rejected NSSAI list for the EPLMN; The method of claim 16 further comprising:

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