CN117981393A - Method, device and system for network slice replacement - Google Patents

Abstract

The present disclosure describes methods, systems, and devices for performing network slice replacement during a Protocol Data Unit (PDU) session modification procedure or a service request procedure. A method comprising: selecting, by a Radio Access Network (RAN), single network slice selection assistance information (S-NSSAI) to replace a service of the PDU session S-NSSAI; and sending, by the RAN, a message including network slice replacement information for the PDU session to an access and mobility management function (AMF). Another method comprises the following steps: receiving, by the AMF from the RAN, a message for network slice replacement for the PDU session; and determining, by the AMF based on the message, whether to accept the PDU session requiring slice replacement with the corresponding S-NSSAI.

Description

Method, device and system for network slice replacement

Technical Field

The present disclosure relates generally to wireless communications. In particular, the present disclosure relates to methods, devices and systems for performing network slice replacement during a Protocol Data Unit (PDU) session modification procedure or a service request procedure.

Background

Wireless communication technology is pushing the world to an increasingly connected and networked society. High-speed and low-latency wireless communications rely on efficient network resource management and allocation between one or more user devices and one or more radio access network nodes, including but not limited to base stations. New generation networks are expected to provide high speed, low latency, and ultra-reliable communication capabilities, and to meet demands from different industries and users.

With the rapid development of cellular mobile communication systems, such as in current wireless communication protocols, supporting network slice service continuity may encounter various challenges/problems, in some cases, such as, but not limited to, due to operation, administration and maintenance (OAM) reasons or slice congestion in a Radio Access Network (RAN), supporting network slice service continuity may be challenging.

Disclosure of Invention

The present disclosure describes various embodiments for performing network slice replacement in various situations, e.g., during a session modification procedure and/or a service request procedure, that address at least one of the challenges/problems discussed above. Various embodiments in the present disclosure may improve efficiency and performance of service continuity for UEs, thereby improving user experience and/or technical field in wireless communications.

This document relates to methods, systems, and devices for wireless communications, and more particularly, to methods, systems, and devices for performing network slice replacement during a Protocol Data Unit (PDU) session modification procedure or a service request procedure.

In one embodiment, the present disclosure describes a method for wireless communication. The method comprises the following steps: selecting, by a Radio Access Network (RAN), a single network slice selection assistance information (S-NSSAI) to replace a service S-NSSAI of a Protocol Data Unit (PDU) session; and sending, by the RAN, a message including network slice replacement information for the PDU session to an access and mobility management function (AMF).

In another embodiment, the present disclosure describes a method for wireless communication. The method comprises the following steps: receiving, by an access and mobility management function (AMF), a message from a Radio Access Network (RAN) for a network slice replacement for a Protocol Data Unit (PDU) session; and determining, by the AMF based on the message, whether to accept the PDU session requiring slice replacement with corresponding single network slice selection assistance information (S-NSSAI).

In another embodiment, the present disclosure describes a method for wireless communication. The method comprises the following steps: receiving, by a Session Management Function (SMF), first single network slice selection assistance information (S-NSSAI) corresponding to a Protocol Data Unit (PDU) session requiring slice replacement from an access and mobility management function (AMF); determining, by the SMF, whether to accept the PDU session with the first S-NSSAI; in response to determining to accept the PDU session: triggering, by the SMF, replacement of a second S-NSSAI with the first S-NSSAI for the PDU session, and storing, by the SMF, the S-NSSAI and the second S-NSSAI associated with the same PDU session identification; in response to determining not to accept the PDU session: triggering a PDU session release procedure by the SMF; and sending, by the SMF, an N4 message to a User Plane Function (UPF), the N4 message comprising at least one of: the first S-NSSAI, network instance, or updated rule.

In another embodiment, the present disclosure describes a method for wireless communication. The method comprises the following steps: receiving, by a Session Management Function (SMF) from an access and mobility management function (AMF), a network slice replacement fallback indication, the fallback indication indicating replacement of a first S-NSSAI with second single network slice selection assistance information (S-NSSAI) for an associated PDU session, the second S-NSSAI corresponding to the PDU session at first establishment of the PDU session; determining, by the SMF, whether to accept network slice replacement for the PDU session with the second S-NSSAI; in response to determining to accept the network slice replacement with the second S-NSSAI: removing, by the SMF, the first S-NSSAI stored by the SMF that is associated with the PDU session, and sending, by the SMF, an N4 message to a User Plane Function (UPF), the N4 message including at least one of: the second S-NSSAI, access Network (AN) tunnel information, network instance, or updated rules.

In another embodiment, the present disclosure describes a method for wireless communication. The method comprises the following steps: receiving, by a User Plane Function (UPF), a request message from a Session Management Function (SMF), the request message comprising at least one of: single network slice selection assistance information (S-NSSAI), network instance, or updated rules corresponding to a Protocol Data Unit (PDU) session requiring slice replacement; and sending, by the UPF to the SMF, a response message including Core Network (CN) tunnel information.

In some other embodiments, an apparatus for wireless communication may include a memory storing instructions and processing circuitry in communication with the memory. When the processing circuitry executes the instructions, the processing circuitry is configured to perform the above method.

In some other embodiments, an apparatus for wireless communication may include a memory storing instructions and processing circuitry in communication with the memory. When the processing circuitry executes the instructions, the processing circuitry is configured to perform the above method.

In some other embodiments, a computer-readable medium comprising instructions that, when executed by a computer, cause the computer to perform the above method.

The above and other aspects and implementations thereof are described in more detail in the accompanying drawings, description and claims.

Drawings

Fig. 1A illustrates an example of a wireless communication system including more than one radio access network node and one or more user equipment.

Fig. 1B illustrates an exemplary communication network including various terminal devices, carrier networks, data networks, and service applications.

Fig. 1C illustrates an exemplary network function or network node in a communication network.

Fig. 2 shows an example of a network node.

Fig. 3 shows an example of a user equipment.

Fig. 4A shows a flow chart of a method for wireless communication.

Fig. 4B shows a flow chart of a method for wireless communication.

Fig. 4C shows a flow chart of a method for wireless communication.

Fig. 4D shows a flow chart of a method for wireless communication.

Fig. 4E shows a flow chart of a method for wireless communication.

Fig. 5 shows a schematic diagram of an exemplary embodiment for wireless communication.

Fig. 6 shows a schematic diagram of an exemplary embodiment for wireless communication.

Fig. 7 shows a schematic diagram of an exemplary embodiment for wireless communication.

Fig. 8 shows a schematic diagram of an exemplary embodiment for wireless communication.

Fig. 9 shows a schematic diagram of an exemplary embodiment for wireless communication.

Detailed Description

The present disclosure will now be described in detail below with reference to the attached drawing figures, which form a part of the present disclosure and which show by way of illustration specific examples of embodiments. It should be noted, however, that the present disclosure may be embodied in a variety of different forms and, thus, the covered or claimed subject matter is not to be construed as limited to any of the embodiments set forth below.

Throughout the specification and claims, terms may have, in addition to the meanings explicitly set forth, a implied or implied nuances in the context. Likewise, the phrase "in one embodiment" or "in some embodiments" as used herein does not necessarily refer to the same embodiment, and the phrase "in another embodiment" or "in other embodiments" as used herein does not necessarily refer to different embodiments. The phrase "in one implementation" or "in some implementations" as used herein does not necessarily refer to the same implementation, and the phrase "in another implementation" or "in other implementations" as used herein does not necessarily refer to a different implementation. For example, the claimed subject matter is intended to include all or a combination of some of the example embodiments or implementations.

Generally, the term may be understood, at least in part, from the usage in the context. For example, terms such as "and," "or" and/or "as used herein may include a wide variety of meanings that may depend at least in part on the context in which such terms are used. Generally, "or" if used with an association list (such as A, B or C) is intended to mean A, B and C (used herein in an inclusive sense), and A, B or C (used herein in an exclusive sense). Furthermore, the terms "one or more" or "at least one" as used herein, depending at least in part on the context, may be used to describe any feature, structure, or characteristic in the singular sense, or may be used to describe a combination of features, structures, or characteristics in the plural sense. Similarly, terms such as "a," "an," or "the" may also be construed to convey a singular usage or a plural usage, depending at least in part on the context. Furthermore, the term "based on" or "dependent on" may be understood as not necessarily intended to convey an exclusive set of factors, but instead may allow for the presence of additional factors that need not be explicitly described, again, depending at least in part on the context.

The present disclosure describes various methods and apparatus for performing network slice replacement during a Protocol Data Unit (PDU) session modification procedure or a service request procedure.

Wireless communication technology is pushing the world to an increasingly connected and networked society. High-speed and low-latency wireless communications rely on efficient network resource management and allocation between one or more user devices and one or more radio access network nodes, including but not limited to base stations. New generation networks are expected to provide high speed, low latency, and ultra-reliable communication capabilities, and to meet demands from different industries and users.

With the rapid development of cellular mobile communication systems, such as in current wireless communication protocols, supporting network slice service continuity may encounter various challenges/problems, in some cases, such as, but not limited to, due to operation, administration and maintenance (OAM) reasons or slice congestion in a Radio Access Network (RAN), supporting network slice service continuity may be challenging. One of the difficulties/problems may include an ambiguous solution for the affected core network and/or User Equipment (UE) from an end-to-end system perspective. In some cases, a new generation RAN (NG-RAN) may decide to release some or all PDU sessions established according to a particular single network slice selection assistance information (S-NSSAI), e.g. due to OAM reasons or network slice congestion; also, as such PDU sessions are released, network slice service continuity may not be guaranteed for the affected UEs.

The present disclosure describes various embodiments for network slice replacement during Protocol Data Unit (PDU) session modification procedures or service request procedures in order to support network slice service continuity during UE movement in certain scenarios, where network slices are not available or network slice resources are insufficient in NG-RAN nodes. Various embodiments may address at least the above issues, supporting service continuity for UEs.

In various embodiments of the present disclosure, a Radio Access Network (RAN) may refer to a new generation radio access network (NG-RAN); and/or "RAN" and "NG-RAN" may be used interchangeably in various embodiments. In this disclosure, network slice may refer to a logical network that provides specific network capabilities and network characteristics; and/or a network slice instance may refer to a set of network function instances and required resources (e.g., computing, storage, and networking resources) that form a deployed network slice.

Fig. 1A illustrates a wireless communication system 100 that includes some or all of the following: a core network (CN, 102), one or more access network nodes (or Radio Access Networks (RANs), 118 and 119), and/or one or more User Equipments (UEs) (110, 111, and 112).

The core network (102) may communicate with the one or more access network nodes (118 and/or 119). The UE may be connected to one network node 118, e.g., a Radio Access Network (RAN) node (118 or 119) and/or a Core Network (CN) node (102). The radio network nodes (118 and 119) may comprise network base stations, which may be nodebs (NB, e.g. gNB) in a mobile telecommunication environment. Each of the UEs (110, 111, and 112) may communicate wirelessly with a wireless network node (118 and/or 119) via one or more wireless channels 115. For example, the first UE 110 may wirelessly communicate with the first network node 118 via a channel comprising a plurality of wireless channels during a period of time; during another time period, the first UE 110 may wirelessly communicate with the second network node 119 via a channel comprising a plurality of wireless channels.

An exemplary communication network (shown as 120 in fig. 1B) in various embodiments may include some or all of the following: terminal devices 121 and 122, carrier network 123, various service applications 129, and other data networks 128. For example, the operator network 123 may include an access network (or Radio Access Network (RAN) 124) and a core network 126. Carrier network 123 may be configured to transfer voice, data, and other information (collectively referred to as data traffic) between terminal devices 121 and 122, between terminal devices and service applications 129, and/or between terminal devices and other data networks 128. A communication session and corresponding data path may be established and configured for such data transmission. The access network 124 may be configured to provide network access to the core network 126 to terminal devices. The access network may, for example, support wireless access via radio resources, or wired access. The core network may include various network nodes or network functions configured to control communication sessions and perform network access management and data traffic routing. The service applications may be hosted by various application servers that are accessible by the terminal device through the core network of the operator network. The service application 129 may be deployed as a data network outside the core network. Likewise, other data networks 128 may be accessed by terminal devices through the core network 126 and may appear as data destinations or data sources for particular communication sessions instantiated in the carrier network 123.

The core network 126 of fig. 1B may include various network nodes or functions that are geographically distributed and interconnected to provide network coverage for the service area of the carrier network 123. These network nodes or functions may be implemented as dedicated hardware network elements. Or these network nodes or functions may be virtualized and implemented as virtual machines or software entities. Each network node may be configured with one or more types of network functions. These network nodes or network functions may collectively provide provisioning and routing functions for the core network 126. The terms "network node" and "network function" are used interchangeably in this disclosure.

Fig. 1C also shows an exemplary architecture of a 5G system (5 GS), which also shows an exemplary partitioning of Network Functions (NF) in the core network of the communication network 150. Although only a single instance of a network node or network function is shown in fig. 1C, one of ordinary skill in the art will readily appreciate that each of these network nodes may be instantiated as multiple instances of a network node distributed throughout the core network.

As shown in fig. 1C, the 5GS may include at least one UE (152), at least one RAN (154), at least one core network (155), and/or at least one data network (DN, 170). The core network may include, but is not limited to, some or all of the following: at least one access and mobility management function (AMF), at least one Session Management Function (SMF), and/or at least one User Plane Function (UPF). Exemplary signaling and data exchanges between various types of network nodes/functions over various communication interfaces are indicated by the various connection lines in fig. 1C. Such signaling and data exchanges may be carried by signaling or data messages that follow a predetermined format or protocol.

Referring to at least one RAN (154), during UE movement, an inter-NG-RAN handover procedure may be initiated to handover the UE from a Source NG-RAN (Source NG-RAN) to a Target NG-RAN (Target NG-RAN).

Referring to AMF (156), the Network Function (NF) may include functions such as UE mobility management, reachability management, connection management, and registration management. The AMF terminates the RAN Control Plane (CP) interface N2 and the Non Access Stratum (NAS) interface N1, NAS ciphering and integrity protection. It also transparently transmits N2 SM information between the RAN and the SMF.

Referring to SMF (158), the NF includes the following functions: session establishment, modification and release, UE IP address assignment and management, selection and control of User Plane (UP) functions, etc.

Referring to UPF (160), the NF serves as an anchor for intra/inter Radio Access Technology (RAT) mobility and as an external PDU session interconnect point with a Data Network (DN). The UPF also routes and forwards data packets according to the indication from the SMF. It also buffers Downlink (DL) data when the UE is in idle mode. The UPF may receive uplink user plane traffic from the RAN via the N3 interface and send downlink user plane traffic to the RAN.

Fig. 2 shows an example of an electronic device 200 for implementing a network base station. The exemplary electronic device 200 may include radio transmit/receive (Tx/Rx) circuitry 208 to transmit/receive communications with UEs and/or other base stations. The electronic device 200 may also include network interface circuitry 209 to communicate base stations with other base stations and/or core networks (e.g., optical or wireline interconnections, ethernet, and/or other data transmission media/protocols). The electronic device 200 may optionally include an input/output (I/O) interface 206 to communicate with an operator or the like.

The electronic device 200 may also include system circuitry 204. The system circuitry 204 may include processor(s) 221 and/or memory 222. Memory 222 may include an operating system 224, instructions 226, and parameters 228. The instructions 226 may be configured for one or more of the processors 124 to perform the functions of the network node. Parameters 228 may include parameters to support execution of instructions 226. For example, the parameters may include network protocol settings, bandwidth parameters, radio frequency map assignments, and/or other parameters.

Fig. 3 shows an example of an electronic device for implementing a terminal device 300, e.g., a User Equipment (UE). The UE 300 may be a mobile device such as a smart phone or a mobile communication module disposed in a vehicle. The UE 300 may include a communication interface 302, system circuitry 304, input/output interfaces (I/O) 306, display circuitry 308, and a storage device 309. The display circuitry may include a user interface 310. The system circuitry 304 may comprise any combination of hardware, software, firmware, or other logic/circuitry. System circuitry 304 may be implemented, for example, with one or more systems on a chip (SoC), application Specific Integrated Circuits (ASICs), discrete analog and digital circuits, and other circuitry. The system circuitry 304 may be part of the implementation of any desired functionality in the UE 300. In this regard, the system circuitry 304 may include logic that facilitates, for example, the following: decoding and playing music and video (e.g., MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV decoding and playback); running an application program; accepting user input; saving and retrieving application data; establishing, maintaining and terminating a cellular telephone call or data connection for an internet connection (as one example); establishing, maintaining, and terminating a wireless network connection, bluetooth connection, or other connection; and displaying the relevant information on the user interface 310. The user interface 310 and input/output (I/O) interface 306 may include a graphical user interface, a touch-sensitive display, haptic feedback or other haptic output, voice or facial recognition input, buttons, switches, speakers, and other user interface elements. Additional examples of I/O interfaces 306 may include microphones, video and still image cameras, temperature sensors, vibration sensors, rotation and orientation sensors, headphones and microphone input/output jacks, universal Serial Bus (USB) connectors, memory card slots, radiation sensors (e.g., I R sensors), and other input types.

Referring to fig. 3, communication interface 302 may include Radio Frequency (RF) transmit (Tx) and receive (Rx) circuitry 316 that processes the transmission and reception of signals through one or more antennas 314. Communication interface 302 may include one or more transceivers. The transceiver may be a wireless transceiver that includes modulation/demodulation circuitry, digital-to-analog converters (DACs), shaping tables, analog-to-digital converters (ADCs), filters, waveform shapers, filters, preamplifiers, power amplifiers, and/or other logic for transmitting and receiving over one or more antennas or (for some devices) over a physical (e.g., wired) medium. The transmitted and received signals may follow any of a variety of different arrays of formats, protocols, modulations (e.g., QPSK, 16-QAM, 64-QAM, or 256-QAM), channels, bit rates, and codes. As a specific example, the communication interface 302 may include a transceiver that supports transmission and reception under 2G, 3G, BT, wiFi, universal Mobile Telecommunications System (UMTS), high Speed Packet Access (HSPA) +, 4G/Long Term Evolution (LTE), 5G, 6G, any new generation telecommunications, and/or any future generation wireless communication standards. However, the techniques described below may be used for other wireless communication techniques that originate from the 3 rd generation partnership project (3 GPP), the GSM Association, 3GPP2, I EEE, or other partnership or standards body.

Referring to fig. 3, system circuitry 304 may include one or more processors 321 and memory 322. Memory 322 stores, for example, an operating system 324, instructions 326, and parameters 328. The processor 321 is configured to execute instructions 326 to perform the desired functions for the UE 300. Parameters 328 may provide and specify configuration and operation options for instructions 326. The memory 322 may also store any BT, wiFi, 3G, 4G, 5G, 6G, any new generation telecommunications or other data that the UE 300 would send or have received over the communication interface 302. In various implementations, the system power for the UE 300 may be provided by a power storage device such as a battery or a transformer.

The present disclosure describes various embodiments that may be implemented in part or in whole on the network base station and/or user equipment described above in fig. 2-3.

Referring to fig. 4A, the present disclosure describes various embodiments of a method 400 for wireless communication. The method 400 may include some or all of the following steps: step 402, selecting, by a Radio Access Network (RAN), a single network slice selection assistance information (S-NSSAI) to replace a service S-NSSAI of a Protocol Data Unit (PDU) session; and step 404, transmitting, by the RAN, a message including network slice replacement information for the PDU session to an access and mobility management function (AMF). In some implementations, S-NSSAI may refer to old S-NSSAI and service S-NSSAI may refer to standby S-NSSAI. In some other implementations, S-NSSAI may refer to standby S-NSSAI and service S-NSSAI may refer to old S-NSSAI. In some other implementations, the message may be an N2 path switch request message.

In some other implementations, the RAN selects S-NSSAI from the Network Slice Selection Assistance Information (NSSAI) to replace a service associated with the PDU session S-NSSAI, and the message includes S-NSSAI. Various implementations may be in a non-roaming and/or Local Breakout (LBO) roaming scenario. S-NSSAI may be standby S-NSSAI and/or service S-NSSAI may be old S-NSSAI.

In some other implementations, NSSAI includes an S-NSSAI list that is allowed for a User Equipment (UE).

In some other implementations, the method 400 may optionally further include: updated CN tunnel information or updated QoS profile for the PDU session is received by the RAN from the AMF.

In some other implementations, in response to determining that a network slice replacement fallback for the PDU session, the message includes a fallback indication indicating to the AMF to replace the service S-NSSAI with the S-NSSAI, the S-NSSAI corresponding to the PDU session when the PDU session was first established. Various implementations may be performed in a fallback scenario. S-NSSAI may be old S-NSSAI; and/or service S-NSSAI may be standby S-NSSAI.

In some other implementations, user Plane (UP) connection activation for the PDU session is not accepted according to the service S-NSSAI in response to the RAN receiving the S-NSSAI and the service S-NSSAI for the PDU session: the RAN accepting the User Plane (UP) connection activation for the PDU session according to the S-NSSAI, the S-NSSAI corresponding to the PDU session when the PDU session is first established; and the message includes one of: a fallback indication and corresponding Access Network (AN) tunnel information, the fallback indication indicating to the AMF to perform the UP connection activation for the PDU session according to the S-NSSAI, or the S-NSSAI and corresponding Access Network (AN) tunnel information. Various implementations may be performed in the context of a UE-initiated service request procedure to activate a User Plane (UP) connection for a PDU session. S-NSSAI may be old S-NSSAI; and/or service S-NSSAI may be standby S-NSSAI.

Referring to fig. 4B, the present disclosure describes various embodiments of a method 420 for wireless communication. Method 420 may include some or all of the following steps: step 422, receiving, by an access and mobility management function (AMF), a message from a Radio Access Network (RAN) for network slice replacement for a Protocol Data Unit (PDU) session; and step 424, determining, by the AMF based on the message, whether to accept the PDU session requiring slice replacement with corresponding single network slice selection assistance information (S-NSSAI).

In some implementations, the message includes a first S-NSSAI; the AMF determines whether to accept the PDU session requiring slice replacement with the first S-NSSAI; and in response to determining to accept the PDU session with the first S-NSSAI, the AMF sends the first S-NSSAI corresponding to the PDU session to a respective Session Management Function (SMF).

In some other implementations, the first S-NSSAI is configured to replace a second S-NSSAI, the second S-NSSAI corresponding to the PDU session requiring slice replacement when the PDU session is first established. The second S-NSSAI may be the old S-NSSAI.

In some other implementations, step 424 may optionally include: determining, by the AMF, whether the first S-NSSAI and the second S-NSSAI are supported by the same SMF; responsive to determining that the first S-NSSAI and the second S-NSSAI are supported by the same SMF, determining, by the AMF, to accept the PDU session; and/or in response to determining that the first S-NSSAI and the second S-NSSAI are not supported by the same SMF, determining, by the AMF, not to accept the PDU session.

In some other implementations, method 420 may optionally include, in response to determining to accept the PDU session: the respective N2 SM information and the first S-NSSAI are sent by the AMF to the respective SMF and/or the first S-NSSAI and the second S-NSSAI corresponding to the same PDU session identity are stored by the AMF.

In some other implementations, the message includes: a network slice replacement fallback indication indicating to the AMF to replace a first S-NSSAI with a second S-NSSAI for the PDU session, the second S-NSSAI corresponding to the PDU session when the PDU session was first established; and/or the AMF sends the network slice replacement fallback indication for the PDU session to a respective SMF. The first S-NSSAI may be a standby S-NSSAI; and/or the second S-NSSAI may be old S-NSSAI.

In some other implementations, the message includes a second S-NSSAI, the second S-NSSAI corresponding to the PDU session at the time the PDU session was first established; and/or the AMF sends the message to a corresponding SMF, the message comprising the second S-NSSAI of the PDU session. The second S-NSSAI may be the old S-NSSAI.

Referring to fig. 4C, the present disclosure describes various embodiments of a method 440 for wireless communication. The method 440 may include some or all of the following steps: step 442, receiving, by a Session Management Function (SMF), from an access and mobility management function (AMF), first single network slice selection assistance information (S-NSSAI) corresponding to a Protocol Data Unit (PDU) session requiring slice replacement; step 444, determining, by the SMF, whether to accept the PDU session with the first S-NSSAI; step 446, in response to determining to accept the PDU session: triggering, by the SMF, replacement of a second S-NSSAI with the first S-NSSAI for the PDU session, and/or storing, by the SMF, the S-NSSAI and the second S-NSSAI associated with the same PDU session identification; and/or step 448, in response to determining not to accept the PDU session: triggering a PDU session release procedure by the SMF; and/or transmitting, by the SMF, an N4 message to a User Plane Function (UPF), the N4 message comprising at least one of: the first S-NSSAI, network instance, or updated rule.

Referring to fig. 4D, the present disclosure describes various embodiments of a method 460 for wireless communication. The method 460 may include some or all of the following steps: a step 462 of receiving, by a Session Management Function (SMF) from an access and mobility management function (AMF), a network slice replacement fallback indication, the fallback indication indicating replacement of a first S-NSSAI with second single network slice selection assistance information (S-NSSAI) for an associated PDU session, the second S-NSSAI corresponding to the PDU session at first establishment of the PDU session; step 464, determining, by the SMF, whether to accept network slice replacement for the PDU session with the second S-NSSAI; step 466, in response to determining to accept the network slice replacement with the second S-NSSAI: removing, by the SMF, the first S-NSSAI stored by the SMF that is associated with the PDU session, and/or sending, by the SMF, an N4 message to a User Plane Function (UPF), the N4 message including at least one of: the second S-NSSAI, access Network (AN) tunnel information, network instance, or updated rules. The first S-NSSAI may be a standby S-NSSAI; and/or the second S-NSSAI may be old S-NSSAI.

In some implementations, the SMF provides the first S-NSSAI and the second S-NSSAI to the RAN.

In some other implementations, the SMF sends updated Core Network (CN) tunnel information and updated quality of service (QoS) profiles to the RAN.

Referring to fig. 4E, the present disclosure describes various embodiments of a method 480 for wireless communication. Method 480 may include some or all of the following steps: step 482, receiving, by a User Plane Function (UPF), a request message from a Session Management Function (SMF), the request message comprising at least one of: single network slice selection assistance information (S-NSSAI), network instance, or updated rules corresponding to a Protocol Data Unit (PDU) session requiring slice replacement; and/or a step 484 of sending, by the UPF, a response message to the SMF, the response message including Core Network (CN) tunnel information. In some implementations, the S-NSSAI may refer to the old S-NSSAI. In some other implementations, the S-NSSAI may refer to standby S-NSSAI.

In some other implementations, the method 480 may optionally further include: determining, by the UPF, an internal UPF resource based on the S-NSSAI or the network instance; and/or assigning, by the UPF, the CN tunnel information based on the request message from the SMF.

In the following, the present disclosure describes various exemplary embodiments in more detail, which should be considered as examples only and not imposing any limitation on the various embodiments in the present disclosure. Any portion of a single embodiment or multiple embodiments (e.g., a step or steps) may be combined or arranged in any number or any order, as desired. In some embodiments, one or more steps may be performed in parallel, as desired.

Fig. 5 shows a schematic diagram of an exemplary embodiment of a RAN-requested PDU session modification procedure in a non-roaming and/or Local Breakout (LBO) roaming scenario, including some or all of the following: NG-RAN 582, AMF 590, SMF 592, and/or UPF 594.

Roaming is a feature of telecommunication systems that allows one or more subscribers to use their mobile services outside their home network. Their home network may refer to the coverage area of their service provider. Roaming services may include, but are not limited to, placing or receiving calls, sending or receiving mobile data, performing supplementary services such as call forwarding, etc. In Local Breakout (LBO) roaming, data traffic may be routed directly from a visited (or visitor) network (V-network) to the data network, while authentication and processing of subscription data may be handled by the home network. In some cases, only signaling data may be routed to the home network. In Home Routing (HR) roaming, an IP address may be obtained from the home network; and/or the UE may communicate with a visitor (or visitor) SMF (V-SMF) from the visitor network, a visitor (or visitor) UPF (V-UPF) from the visitor network, a home SMF (H-SMF) from the home network, and/or a home UPF (H-UPF) from the home network.

Referring to step 5-1, the ng-RAN (or RAN) may decide to initiate a PDU session modification procedure for one or more PDU sessions.

Referring to step 5-2, the ng-RAN may initiate the PDU session modification procedure by sending an N2 message (i.e., a PDU session resource modification indication message) to the AMF. The message includes a PDU session resource modification indication list, each item in the list having a PDU session Identifier (ID) and N2 SM information. The list may include one or more PDU sessions. The N2 SM information includes Access Network (AN) tunnel information.

Referring to step 5-3, the amf may send Nsmf _ PDUSess ion _ UpdateSMContext request message to the corresponding SMF associated with the PDU session. The message may include N2 SM information.

Referring to step 5-4, when the SMF decides to accept the PDU session modification, the SMF may update the UPF with N4 rules related to the new or modified quality of service (QoS) flow(s). When the SMF cannot accept the PDU session modification, the SMF includes the PDU session associated with the failure cause in the PDU session resource failed modification list and returns to the NG-RAN.

Referring to step 5-5, the smf updates the UPF with N4 rules associated with the new or modified QoS flow(s).

Referring to steps 5-6, the UPF returns an N4 session modify/establish response message with updated information to the SMF when available.

Referring to steps 5-7, the smf transmits Nsmf _ PDUSess ion _ UpdateSMContext response message including N2 SM information to the AMF. For an accepted PDU session, the N2 SM information includes Core Network (CN) tunnel information, updated parameters for the accepted QoS flows. For a failed PDU session, the N2 SM information includes a corresponding failure cause.

Referring to step 5-8, the amf sends an N2 message, i.e., a PDU session resource modification confirm message, to the NG-RAN. The message includes a PDU session resource modification acknowledgement list with a PDU session ID and corresponding N2 SM information for each PDU session. The list may include zero, one, or multiple PDU sessions. The corresponding N2 SM information includes CN tunnel information and/or updated parameters for the accepted QoS flows. The message may also include a PDU session resource failure to modify list with a PDU session ID and corresponding N2 SM information for each PDU session. The list may include zero, one, or multiple PDU sessions. The corresponding N2 SM information includes a failure cause.

Fig. 6 shows a schematic diagram of an exemplary embodiment for performing network slice replacement during a RAN-requested PDU session modification procedure in a Home Routing (HR) roaming scenario, including some or all of the following: NG-RAN 682, AMF 690, V-SMF 692, V-UPF 694, H-SMF 696 and/or H-UPF 698.

Referring to step 6-1, the ng-RAN (or RAN) may decide to initiate a PDU session modification procedure for one or more PDU sessions.

Referring to step 6-2, the ng-RAN initiates the PDU session modification procedure by sending an N2 message (i.e., PDU session resource modification indication message) to the AMF. The message includes a PDU session resource modification indication list, each item in the list having a PDU session ID and N2 SM information. The list may include one or more PDU sessions. The N2 SM information includes AN tunnel information.

Referring to step 6-3, the amf sends Nsmf _ PDUSess ion _ UpdateSMContext request message to the corresponding V-SMF associated with the PDU session. The message includes N2 SM information.

Referring to step 6-4, the v-SMF sends Nsmf _ PDUSess ion _update request message to the H-SMF. The message includes N2 SM information.

Referring to step 6-5, when the H-SMF decides to accept PDU session modification, the H-SMF may update the H-UPF with the N4 rules associated with the new or modified QoS flow(s). When the H-SMF cannot accept PDU session modification, the H-SMF includes the PDU session associated with the failure cause in a PDU session resource unmodified list and returns to the NG-RAN.

The reference to step 6-6,H-SMF may update the H-UPF with the N4 rule associated with the new or modified QoS flow(s).

Referring to step 6-7, the H-UPF responds to the H-SMF with updated information when available.

The Nsmf _ PDUSess ion _update response message is sent to the V-SMF with reference to steps 6-8,H-SMF. For one or more accepted PDU sessions, the message includes updated CN tunnel information, updated parameters for the accepted QoS flows. For one or more failed PDU sessions, the message includes a corresponding failure cause.

The reference step 6-9,V-SMF may update the V-UPF with the N4 rule associated with the new or modified QoS flow(s).

Referring to steps 6-10, the V-UPF responds to the V-SMF with updated information when available.

Referring to step 6-11, the v-SMF transmits Nsmf _ PDUSess ion _ UpdateSMContext response message including the N2 SM information to the AMF. For one or more accepted PDU sessions, the N2 SM information includes updated CN tunnel information, updated parameters for the accepted QoS flows. For one or more failed PDU sessions, the N2 SM information includes a corresponding failure cause.

Referring to steps 6-12, the amf sends an N2 message, e.g., a PDU session resource modification confirm message, to the NG-RAN. The message includes a PDU session resource modification acknowledgement list with a PDU session ID and corresponding N2 SM information for each PDU session. The list may include zero, one, or multiple PDU sessions. The corresponding N2 SM information includes CN tunnel information, updated parameters for the accepted QoS flows. The message may also include a PDU session resource failure to modify list with a PDU session ID and corresponding N2 SM information for each PDU session. The list may include zero, one, or multiple PDU sessions. The corresponding N2 SM information includes a failure cause.

Fig. 7 shows a schematic diagram of an exemplary embodiment for performing network slice replacement during a RAN-requested PDU session modification procedure in a non-roaming and/or Local Breakout (LBO) roaming scenario, including some or all of: NG-RAN 782, AMF 790, SMF 792, and/or UPF 794. The present exemplary embodiments may enable network slice replacement during a PDU session modification procedure when a network slice is congested or unavailable at the NG-RAN, thereby guaranteeing network slice service continuity for affected UEs, thus solving the problem/problem of poor network slice service continuity for affected UEs due to the NG-RAN initiating a PDU session release procedure for such PDU session when a PDU session is associated with a network slice that is congested or unavailable at the NG-RAN.

Referring to step 7-1, for some or all PDU sessions established according to service S-NSSAI, e.g., due to OAM reasons or service S-NSSAI congestion, the NG-RAN may decide to replace service S-NSSAI with a newly selected alternate S-NSSAI. The standby S-NSSAI is selected, for example, from the UE' S allowed NSSAI.

Referring to step 7-2, the ng-RAN may initiate the PDU session modification procedure by sending an N2 message (e.g., a PDU session resource modification indication message) to the AMF. The message includes a PDU session resource modification indication list, each item in the list having a PDU session ID, selected alternate S-NSSAI, and N2 SM information. The list may include one or more PDU sessions. The N2 SM information includes AN tunnel information. The N2 SM information may include the selected standby S-NSSAI.

Referring to step 7-3, the amf may determine whether the PDU session(s) requiring slice replacement may be forwarded to the corresponding SMF. When a PDU session can be forwarded, for example, service S-NSSAI and standby S-NSSAI of the PDU session can be supported by the same SMF, which forwards the N2 SM information and standby S-NSSAI of the PDU session to the corresponding SMF. The AMF stores the old S-NSSAI and the spare S-NSSAI associated with the same PDU session identification.

When a PDU session cannot be forwarded, e.g., service S-NSSAI and standby S-NSSAI cannot be supported by the same SMF, the AMF notifies the SMF to release such PDU session and includes such PDU session in a PDU session resource unmodified list returned to the NG-RAN.

Referring to step 7-4, the amf sends Nsmf _ PDUSess ion _ UpdateSMContext request message to the SMF. The message includes N2 SM information and standby S-NSSAI.

Referring to step 7-5, when the SMF receives a backup S-NSSAI for the PDU session and the SMF decides to accept the replacement, the SMF triggers replacement of the old S-NSSAI with the backup S-NSSAI for the PDU session. The SMF stores the old S-NSSAI and the spare S-NSSAI associated with the same PDU session identification. When the SMF cannot accept the substitution, the SMF triggers a PDU session release procedure.

Referring to step 7-6, the smf sends an N4 session modification request message to the UPF. The message may include alternate S-NSSAI, network instances (e.g., selected based on alternate S-NSSAI), updated rules such as Packet Detection Rules (PDRs) and QoS Enhancement Rules (QER) (e.g., consider alternate S-NSSAI). The UPF can use parameters such as standby S-NSSAI and network instances to determine internal UPF resources. Depending on the network deployment, the CN tunnel information for the old S-NSSAI and the standby S-NSSAI for UPF may be different. In this case, the SMF may require the UPF to allocate new CN tunnel information.

When the UPF cannot support both the old S-NSSAI and the standby S-NSSAI, a new UPF should be selected that supports both S-NSSAI. When a new UPF is selected, the SMF sends an N4 session setup request message with similar parameters to the UPF.

Referring to step 7-7, the UPF returns an N4 session modify/setup response message with updated CN tunnel information to the SMF when available.

Referring to step 7-8, the smf transmits Nsmf _ PDUSess ion _ UpdateSMContext response message including the N2 SM information to the AMF. For one or more accepted PDU sessions, the N2 SM information includes CN tunnel information, updated parameters for the accepted QoS flows, optionally updated QoS profile (S) (e.g., taking into account standby S-NSSAI). For one or more failed PDU sessions, the N2 SM information includes a corresponding failure cause. When the SMF decides to accept a slice replacement for a PDU session from old S-NSSAI to standby S-NSSAI, such a PDU session is considered an accepted PDU session. Otherwise, such a PDU session is considered a failed PDU session.

Referring to steps 7-9, the amf sends an N2 message, e.g., a PDU session resource modification confirm message, to the NG-RAN. The message includes a PDU session resource modification acknowledgement list with a PDU session ID and corresponding N2 SM information for each PDU session. The list may include zero, one, or multiple PDU sessions. The corresponding N2 SM information includes CN tunnel information, updated parameters for the accepted QoS flows, optionally updated QoS profile(s). The message may also include a PDU session resource failure to modify list with a PDU session ID and corresponding N2 SM information for each PDU session. The list may include zero, one, or multiple PDU sessions. The corresponding N2 SM information includes a failure cause.

In some other embodiments, the above-described method may be performed in the event that a network slice backoff is requested for a PDU session. For example, by sending a network slice fallback indication to the AMF and the AMF forwarding the indication to the SMF, the NG-RAN requires replacement of the standby S-NSSAI with the old service S-NSSAI. When accepted, the SMF performs slice replacement for the standby S-NSSAI with the old S-NSSAI for the PDU session. After a successful slice rollback, the SMF removes the stored spare S-NSSAI of the PDU session. The SMF sends an indication to the AMF that instructs the AMF to remove the stored standby S-NSSAI. The AMF removes the stored spare S-NSSAI of the PDU session.

Fig. 8 shows a schematic diagram of an exemplary embodiment for performing network slice replacement during a RAN-requested PDU session modification procedure in a Home Routing (HR) roaming scenario, including some or all of the following: NG-RAN 882, AMF 890, V-SMF 892, V-UPF 894, H-SMF 896, and/or H-UPF 898.

Referring to step 8-1, for some or all PDU sessions established according to service S-NSSAI, e.g., due to OAM reasons or service S-NSSAI congestion, the NG-RAN may decide to replace service S-NSSAI with a newly selected alternate S-NSSAI. The standby S-NSSAI is selected, for example, from the allowed NSSAI list of UEs.

Referring to step 8-2, the ng-RAN may initiate the PDU session modification procedure by sending an N2 message (e.g., a PDU session resource modification indication message) to the AMF. The message includes a PDU session resource modification indication list, each item in the list having a PDU session ID, selected alternate S-NSSAI, and N2 SM information. The list may include one or more PDU sessions. The N2 SM information includes AN tunnel information. The N2 SM information may include the selected standby S-NSSAI.

Referring to step 8-3, the AMF retrieves a mapped Home Public Land Mobile Network (HPLMN) S-NSSAI for standby S-NSSAI from NSSF or based on a local configuration. The AMF determines whether the PDU session(s) requiring slice replacement can be forwarded to the corresponding V-SMF and H-SMF. When a PDU session can be forwarded, for example, service S-NSSAI and backup S-NSSAI can be supported by the same V-SMF, and the mapping HPLMN S-NSSAI of service S-NSSAI and the mapping HPLMN S-NSSAI of backup S-NSSAI can be supported by the same H-SMF, which forwards N2 SM information, the mapping HPLMN S-NSSAI of backup S-NSSAI and backup S-NSSAI to the corresponding V-SMF. AMF stores the mapping HPLMN S-NSSAI of old S-NSSAI, standby S-NSSAI, old S-NSSAI, and the mapping HPLMN S-NSSAI of Standby S-NSSAI in association with the same PDU session identification.

When a PDU session cannot be forwarded, for example, service S-NSSAI and backup S-NSSAI cannot be supported by the same V-SMF and/or mapped HPLMN S-NSSAI of service S-NSSAI and mapped HPLMN S-NSSAI of backup S-NSSAI cannot be supported by the same H-SMF, the AMF notifies the V-SMF to release such PDU session and includes such PDU session in an unmodified list of PDU session resources returned to the NG-RAN.

Referring to step 8-4, the amf sends Nsmf _ PDUSess ion _ UpdateSMContext request message to the V-SMF. The message includes N2 SM information, backup S-NSSAI, and a mapping HPLMN S-NSSAI of backup S-NSSAI.

Referring to step 8-5, when the V-SMF receives a backup S-NSSAI for the PDU session and the V-SMF decides to accept replacement of the old S-NSSAI with the backup S-NSSAI, the V-SMF notifies the H-SMF to update the PDU session. Otherwise, the V-SMF informs the H-SMF to release such PDU session and includes such PDU session in the PDU session resource unmodified list returned to the NG-RAN.

Referring to step 8-6, the v-SMF sends Nsmf _ PDUSess ion _update request message to the H-SMF. The message includes N2 SM information and a mapping HPLMN S-NSSAI for the standby S-NSSAI.

Referring to step 8-7, when the H-SMF receives the mapped HPLMN S-NSSAI of the alternate S-NSSAI and the H-SMF decides to accept the substitution, the H-SMF triggers the substitution of the mapped HPLMN S-NSSAI of the old S-NSSAI with the mapped HPLMN S-NSSAI of the alternate S-NSSAI for the PDU session. The H-SMF stores the mapping HPLMN S-NSSAI of the old S-NSSAI and the mapping HPLMN S-NSSAI of the standby S-NSSAI in association with the same PDU session identification. When the H-SMF cannot accept the substitution, the H-SMF includes such PDU session in a PDU session resource unmodified list returned to the NG-RAN and triggers a PDU session release procedure.

The N4 session modification request message is sent to the H-UPF with reference to steps 8-8,H-SMF. The message may include the mapped HPLMN S-NSSAI of Standby S-NSSAI, the network instance (e.g., selected based on the mapped HPLMN S-NSSAI of Standby S-NSSAI), updated rules such as Packet Detection Rules (PDRs) and QoS Enhancement Rules (QER) (e.g., mapped HPLMN S-NSSAI that considers Standby S-NSSAI). The H-UPF can use parameters such as the mapping HPLMN S-NSSAI of the backup S-NSSAI and the network instance to determine the internal H-UPF resources. Depending on the network deployment, the CN tunnel information of the mapping HPLMN S-NSSAI for the old S-NSSAI and the mapping HPLMN S-NSSAI for the standby S-NSSAI may be different for the H-UPF. In this case, the H-SMF may require the H-UPF to allocate new CN tunnel information.

When the H-UPF cannot support both the old S-NSSAI mapped HPLMN S-NSSAI and the alternate S-NSSAI mapped HPLMN S-NSSAI, a new H-UPF should be selected that supports both S-NSSAI. When a new H-UPF is selected, the H-SMF sends an N4 session setup request message with similar parameters to the H-UPF.

Referring to step 8-9, the H-UPF returns an N4 session modify/setup response message with updated CN tunnel information to the H-SMF when available.

Referring to steps 8-10, the H-SMF sends Nsmf _ PDUSess ion _update response message to the V-SMF. For one or more accepted PDU sessions, the message includes updated CN tunnel information, updated parameters for the accepted QoS flows, optionally updated QoS profile (S) (e.g., HPLMN S-NSSAI, which considers the mapping of Standby S-NSSAI). For one or more failed PDU sessions, the message includes a corresponding failure cause.

When the SMF decides to accept a slice replacement for a PDU session from the old S-NSSAI 'S mapping HPLMN S-NSSAI to the alternate S-NSSAI' S mapping HPLMN S-NSSAI, such a PDU session is considered an accepted PDU session. Otherwise, such a PDU session is considered a failed PDU session.

Referring to steps 8-11, for one or more accepted PDU sessions, the V-SMF stores the old S-NSSAI and alternate S-NSSAI associated with the same PDU session identity. The V-SMF triggers the replacement of the old S-NSSAI with a spare S-NSSAI for the PDU session.

Referring to steps 8-12, the V-SMF sends an N4 session modification request message to the V-UPF. The message may include alternate S-NSSAI, network instances (e.g., selected based on alternate S-NSSAI), updated rules such as Packet Detection Rules (PDRs) and QoS Enhancement Rules (QER) (e.g., consider alternate S-NSSAI). The V-UPF can use parameters such as standby S-NSSAI and network instances to determine the internal V-UPF resources. The CN tunnel information for the old S-NSSAI and the spare S-NSSAI for V-UPF may be different depending on the network deployment. In this case, the V-SMF may require the V-UPF to allocate new CN tunnel information.

When the V-UPF cannot support both the old S-NSSAI and the standby S-NSSAI, a new V-UPF should be selected that supports both S-NSSAI. When a new V-UPF is selected, the V-SMF sends an N4 session setup request message with similar parameters to the V-UPF.

Referring to steps 8-13, the V-UPF returns an N4 session modify/setup response message with updated CN tunnel information to the V-SMF when available.

Referring to steps 8-14, the smf transmits Nsmf _ PDUSess ion _ UpdateSMContext response message including the N2 SM information to the AMF. For one or more accepted PDU sessions, the N2 SM information includes updated CN tunnel information, updated parameters for the accepted QoS flows, optionally updated QoS profile (S) (e.g., taking into account standby S-NSSAI). For one or more failed PDU sessions, the N2 SM information includes a corresponding failure cause.

Referring to steps 8-15, the amf sends an N2 message, e.g., a PDU session resource modification confirm message, to the NG-RAN. The message includes a PDU session resource modification acknowledgement list with a PDU session ID and corresponding N2 SM information for each PDU session. The list may include zero, one, or multiple PDU sessions. The corresponding N2 SM information includes CN tunnel information, updated parameters for the accepted QoS flows, optionally updated QoS profile(s). The message also optionally includes a PDU session resource failure to modify list with PDU session ID and corresponding N2 SM information for each PDU session. The list may include zero, one, or multiple PDU sessions. The corresponding N2 SM information includes a failure cause.

In some other embodiments, the above-described method may be performed in the event that a network slice backoff is requested for a PDU session. For example, by sending a network slice fallback indication to the AMF and the AMF forwarding the indication to the SMF, the NG-RAN requires replacement of the standby S-NSSAI with the old service S-NSSAI. When accepted, the SMF performs slice replacement for the standby S-NSSAI with the old S-NSSAI for the PDU session. After a successful slice rollback, the SMF removes the stored spare S-NSSAI of the PDU session. The SMF sends an indication to the AMF that instructs the AMF to remove the stored standby S-NSSAI. The AMF removes the stored spare S-NSSAI of the PDU session.

Fig. 9 shows a schematic diagram of an exemplary embodiment for performing a UE-initiated service request procedure to activate a User Plane (UP) connection for a PDU session, including some or all of the following: UE 980, NG-RAN 982, AMF 990, SMF 992, and/or UPF 994. In some implementations, where the UE has established a PDU session with S-NSSAI (e.g., old S-NSSAI) and the S-NSSAI has been replaced with a standby S-NSSAI, both the old S-NSSAI and standby S-NSSAI are stored in the PDU session context in the SMF when the UE enters the CM-IDLE state or user plane resources of such a PDU session are released. Various embodiments (e.g., the present exemplary embodiment) may provide a mechanism for user plane reactivation for PDU sessions associated with old S-NSSAI and alternate S-NSSAI.

Referring to step 9-1, a UE in a connection management IDLE (CM-IDLE) state or a CM connected (CM-connected) state triggers a service request procedure by transmitting a service request message to the RAN to activate a User Plane (UP) connection for a PDU session(s). The service request message includes a list of PDU sessions to be activated.

Referring to step 9-2, the ran forwards the service request message to the AMF.

Referring to step 9-3, the amf determines the PDU session(s) for which the UP connection(s) may be activated and sends a Nsmf _ PDUSess ion _ UpdateSMContext request message with operation type set to "UP active" to the SMF(s) associated with the PDU session(s) to indicate user plane resources are established for the PDU session(s).

Referring to step 9-4, the SMF knows that the PDU session is associated with the old S-NSSAI and the spare S-NSSAI based on the PDU session context. The SMF requests CN tunnel information and sends an N4 session setup/modification request message to the UPF. The message may include alternate S-NSSAI, the target network instance (e.g., selected based on alternate S-NSSAI), rules such as Packet Detection Rules (PDRs) and QoS Enhancement Rules (QER) (e.g., consider alternate S-NSSAI).

Referring to steps 9-5, the UPF can use parameters, such as standby S-NSSAI and network instances, to determine internal UPF resources. The UPF sends an N4 session setup/modification response message to the SMF. The UPF provides CN tunnel information to the SMF.

Referring to step 9-6, the smf transmits Nsmf _ PDUSess ion _ UpdateSMContext response message including the N2 SM information to the AMF. For PDU sessions for which the SMF has determined to accept UP connection activation, the N2 SM information includes PDU session ID, qoS profile (S), CN N3 tunnel information, old S-NSSAI, and/or Standby S-NSSAI.

Referring to step 9-7, the amf forwards the N2 SM information received from the SMF to the RAN.

Referring to step 9-8, the RAN performs Radio Resource Control (RRC) connection reconfiguration with the UE according to QoS information of all QoS flows of the PDU session(s) whose UP connection is activated.

Referring to steps 9-9, when the RAN accepts UP connection activation for a PDU session according to standby S-NSSAI, the service request procedure may continue as described in other implementations/embodiments or according to existing procedures.

Otherwise, when the RAN does not accept UP connection activation for PDU sessions according to the standby S-NSSAI, instead of the RAN accepting UP connection activation for PDU sessions according to the old S-NSSAI, the RAN provides a back-off indication to the AMF indicating that UP connection for PDU sessions is activated according to the old S-NSSAI, or alternatively, provides the old S-NSSAI and associated AN tunnel information.

Referring to steps 9-10, the amf sends Nsmf _ PDUSess ion _ UpdateSMContext request message to the SMF. The message includes AN indication or old S-NSSAI and AN tunnel information received from the RAN.

Referring to steps 9-11, when the SMF accepts the UP connection activation for the PDU session according to the old S-NSSAI, the SMF removes the stored standby S-NSSAI and sends an N4 session modification request message to the UPF. The message may include AN tunnel information, target network instances (e.g., selected based on old S-NSSAI), rules such as Packet Detection Rules (PDR) and QoS Enhancement Rules (QER) (e.g., accounting for old S-NSSAI).

Referring to steps 9-12, the upf sends an N4 session modification response message to the SMF. The message includes updated CN tunnel information.

Referring to steps 9-13, the smf sends Nsmf _ PDUSess ion _ UpdateSMContext response message to the AMF with an indication instructing the AMF to remove the stored standby S-NSSAI. The AMF removes the stored standby S-NSSAI.

Referring to steps 9-14, the smf sends N2 SM information to the RAN via the AMF, including updated CN tunnel information and QoS profile(s) for the PDU session (when needed).

The present disclosure describes methods, apparatus, and computer-readable media for wireless communication. The present disclosure addresses the problem of performing network slice replacement during a Protocol Data Unit (PDU) session modification procedure or a service request procedure. Methods, apparatus, and computer-readable media described in the present disclosure may facilitate performance of wireless communications by performing network slice replacement during a Protocol Data Unit (PDU) session modification procedure or a service request procedure, thereby improving efficiency and overall performance. The methods, apparatus, and computer readable media described in this disclosure may improve the overall efficiency of a wireless communication system.

Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present technology are in any single implementation thereof. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present technical solution. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.

Furthermore, the described features, advantages, and characteristics of the present technology may be combined in any suitable manner in one or more embodiments. One of ordinary skill in the relevant art will recognize, in view of the description herein, that the present technology may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the present subject matter.

Claims (21)

1. A method for wireless communication, comprising:

Selecting, by a Radio Access Network (RAN), a single network slice selection assistance information (S-NSSAI) to replace a service S-NSSAI of a Protocol Data Unit (PDU) session; and

A message including network slice replacement information for the PDU session is sent by the RAN to an access and mobility management function (AMF).

2. The method according to claim 1, wherein:

the RAN selecting the S-NSSAI from Network Slice Selection Assistance Information (NSSAI) to replace the service S-NSSAI associated with the PDU session, and

The message includes the S-NSSAI.

3. The method according to claim 2, wherein:

The NSSAI includes an S-NSSAI list that is allowed for a User Equipment (UE).

4. The method as recited in claim 2, further comprising:

updated CN tunnel information or updated QoS profile for the PDU session is received by the RAN from the AMF.

5. The method according to claim 1, wherein:

In response to determining that a network slice replacement fallback for the PDU session, the message includes a fallback indication indicating to the AMF to replace the service S-NSSAI with the S-NSSAI, the S-NSSAI corresponding to the PDU session when the PDU session was first established.

6. The method according to claim 1, wherein:

in response to the RAN receiving the S-NSSAI and the service S-NSSAI of the PDU session and not accepting User Plane (UP) connection activation for the PDU session in accordance with the service S-NSSAI:

The RAN accepts the User Plane (UP) connection activation for the PDU session according to the S-NSSAI,

The S-NSSAI corresponds to the PDU session when the PDU session is first established; and

The message includes one of:

a back-off indication indicating to the AMF to the UP connection activation for the PDU session according to the S-NSSAI, and corresponding Access Network (AN) tunnel information, or

The S-NSSAI and corresponding Access Network (AN) tunnel information.

7. A method for wireless communication, comprising:

Receiving, by an access and mobility management function (AMF), a message from a Radio Access Network (RAN) for a network slice replacement for a Protocol Data Unit (PDU) session; and

Determining, by the AMF based on the message, whether to accept the PDU session requiring slice replacement with corresponding single network slice selection assistance information (S-NSSAI).

8. The method of claim 7, wherein:

the message includes a first S-NSSAI;

the AMF determines whether to accept the PDU session requiring slice replacement with the first S-NSSAI; and

In response to determining to accept the PDU session with the first S-NSSAI, the AMF sends the first S-NSSAI corresponding to the PDU session to a respective Session Management Function (SMF).

9. The method according to claim 8, wherein:

the first S-NSSAI is configured to replace a second S-NSSAI, the second S-NSSAI corresponding to the PDU session requiring slice replacement when the PDU session is first established.

10. The method of claim 9, wherein the determining whether to accept the PDU session requiring slice replacement with the first S-NSSAI comprises:

determining, by the AMF, whether the first S-NSSAI and the second S-NSSAI are supported by the same SMF;

Responsive to determining that the first S-NSSAI and the second S-NSSAI are supported by the same SMF, determining, by the AMF, to accept the PDU session; and

In response to determining that the first S-NSSAI and the second S-NSSAI are not supported by the same SMF, determining, by the AMF, not to accept the PDU session.

11. The method as recited in claim 10, further comprising:

In response to determining to accept the PDU session:

Transmitting, by the AMF to the respective SMF, the respective N2 SM information and the first S-NSSAI, and

The first S-NSSAI and the second S-NSSAI, which correspond to the same PDU session identification, are stored by the AMF.

12. The method of claim 7, wherein:

The message includes a network slice replacement fallback indication indicating to the AMF to replace a first S-NSSAI with a second S-NSSAI for the PDU session, the second S-NSSAI corresponding to the PDU session at the time the PDU session was first established; and

The AMF sends the network slice replacement fallback indication for the PDU session to the respective SMF.

13. The method of claim 7, wherein:

the message includes a second S-NSSAI, the second S-NSSAI corresponding to the PDU session when the PDU session is first established; and

The AMF sends the message to a corresponding SMF, the message including the second S-NSSAI of the PDU session.

14. A method for wireless communication, comprising:

Receiving, by a Session Management Function (SMF), first single network slice selection assistance information (S-NSSAI) corresponding to a Protocol Data Unit (PDU) session requiring slice replacement from an access and mobility management function (AMF);

Determining, by the SMF, whether to accept the PDU session with the first S-NSSAI;

In response to determining to accept the PDU session:

triggering by the SMF to replace a second S-NSSAI with the first S-NSSAI for the PDU session, and

Storing, by the SMF, the S-NSSAI and the second S-NSSAI associated with a same PDU session identification;

in response to determining not to accept the PDU session:

Triggering a PDU session release procedure by the SMF; and

Transmitting, by the SMF, an N4 message to a User Plane Function (UPF), the N4 message including at least one of: the first S-NSSAI, network instance, or updated rule.

15. A method for wireless communication, comprising:

Receiving, by a Session Management Function (SMF) from an access and mobility management function (AMF), a network slice replacement fallback indication, the fallback indication indicating replacement of a first S-NSSAI with second single network slice selection assistance information (S-NSSAI) for an associated PDU session, the second S-NSSAI corresponding to the PDU session at first establishment of the PDU session;

Determining, by the SMF, whether to accept network slice replacement for the PDU session with the second S-NSSAI;

In response to determining to accept the network slice replacement with the second S-NSSAI:

Removing, by the SMF, the first S-NSSAI stored by the SMF that is associated with the PDU session, and

Transmitting, by the SMF, an N4 message to a User Plane Function (UPF), the N4 message including at least one of: the second S-NSSAI, access Network (AN) tunnel information, network instance, or updated rules.

16. The method according to any one of claims 14 and 15, wherein:

The SMF provides the first S-NSSAI and the second S-NSSAI to the RAN.

17. The method of any one of claims 14, 15, and 16, wherein:

the SMF sends updated Core Network (CN) tunnel information and updated quality of service (QoS) profiles to the RAN.

18. A method for wireless communication, comprising:

Receiving, by a User Plane Function (UPF), a request message from a Session Management Function (SMF), the request message comprising at least one of: single network slice selection assistance information (S-NSSAI), network instance, or updated rules corresponding to a Protocol Data Unit (PDU) session requiring slice replacement; and

A response message is sent by the UPF to the SMF, the response message including Core Network (CN) tunnel information.

19. The method of claim 18, further comprising:

determining, by the UPF, an internal UPF resource based on the S-NSSAI or the network instance; and

The CN tunnel information is allocated by the UPF based on the request message from the SMF.

20. A wireless communication device comprising a processor and a memory, wherein the processor is configured to read codes from the memory and implement the method of any one of claims 1-19.

21. A computer program product comprising computer readable program medium code stored thereon, which when executed by a processor causes the processor to implement the method according to any of claims 1 to 19.