WO2022099475A1 - Session management method, terminal device and network device - Google Patents

Abstract

The present application relates to a session management method, a terminal device and a network device. The method may comprise: in the case that a terminal device leaves a first cell supporting first slice information and enters a second cell that does not support the first slice information, the terminal device receives second slice information supported by the second cell; the terminal device releases a session using the first slice information; and the terminal device establishes a session by using the second slice information. According to the embodiments of the present application, in the case that the terminal device leaves a first cell supporting first slice information and enters a second cell that does not support the first slice information, the terminal device receives second slice information supported by the second cell, can release a session using the first slice information, and establishes a session by using the second slice information, thereby helping to maintain the service continuity of the terminal device.

Description

Session management method, terminal device and network device technical field

The present application relates to the field of communications, and more particularly, to a session management method, terminal device and network device.

Background technique

Network slicing can be deployed in fifth-generation communication (5th-Generation, 5G) networks. A network slice can be identified using a single network slice selection assistance information (Single-Network Slice Selection Assistance Information, S-NSSAI). The set of S-NSSAI is called Network Slice Selection Assistance Information (NSSAI). When a User Equipment (UE) needs to use a network slice, it needs to first request the network to use the slice. After the network agrees, a Packet Data Unit (PDU) session is established in the slice to transmit data. During network deployment, base stations in different areas may support different network slices. When a UE moves to an area that supports different network slices, how to ensure service continuity is a problem that needs to be considered.

SUMMARY OF THE INVENTION

The embodiments of the present application provide a session management method, a terminal device, and a network device, which can maintain the service continuity of the terminal device.

The embodiment of the present application provides a session management method, including:

When the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information, the terminal device receives the second slice information supported by the second cell;

The terminal device releases the session using the first slice information;

The terminal device establishes a session using the second slice information.

An embodiment of the present application provides a method in which, when a terminal device leaves a first cell that supports the first slice information and enters a second cell that does not support the first slice information, the network device sends the terminal device the information supported by the second cell. Second slice information.

An embodiment of the present application provides a terminal device, including:

a receiving unit, configured to receive the second slice information supported by the second cell when the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information;

a release unit for releasing the session using the first slice information;

an establishing unit, configured to establish a session by using the second slice information.

An embodiment of the present application provides a network device, including:

A sending unit, configured to send the second slice information supported by the second cell to the terminal device when the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information .

An embodiment of the present application provides a terminal device, including a processor and a memory. The memory is used for storing a computer program, and the processor is used for calling and running the computer program stored in the memory, so that the terminal device executes the above-mentioned session management method.

An embodiment of the present application provides a network device including a processor and a memory. The memory is used for storing a computer program, and the processor is used for calling and running the computer program stored in the memory, so that the network device executes the above-mentioned session management method.

An embodiment of the present application provides a chip for implementing the above session management method.

Specifically, the chip includes: a processor for invoking and running a computer program from the memory, so that the device installed with the chip executes the above-mentioned session management method.

An embodiment of the present application provides a computer-readable storage medium for storing a computer program, and when the computer program is executed by a device, the device enables the device to execute the above-mentioned session management method.

An embodiment of the present application provides a computer program product, including computer program instructions, and the computer program instructions cause a computer to execute the above session management method.

An embodiment of the present application provides a computer program, which, when running on a computer, causes the computer to execute the above-mentioned session management method.

In this embodiment of the present application, when the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information, the terminal device receives the second slice information supported by the second cell and can release the Using the session of the first slice information and establishing the session using the second slice information is conducive to maintaining the service continuity of the terminal device.

Description of drawings

FIG. 1 is a schematic diagram of an application scenario according to an embodiment of the present application.

2 is a schematic diagram of an exemplary 5G network system architecture.

3 is a schematic diagram of an exemplary network slice.

FIG. 4 is a schematic flowchart of a session management method according to an embodiment of the present application.

FIG. 5 is a schematic flowchart of a session management method according to another embodiment of the present application.

FIG. 6 is a schematic flowchart of a session management method according to another embodiment of the present application.

FIG. 7 is a schematic flowchart of a session management method according to another embodiment of the present application.

FIG. 8 is a schematic block diagram of a terminal device according to an embodiment of the present application.

FIG. 9 is a schematic block diagram of a terminal device according to another embodiment of the present application.

FIG. 10 is a schematic block diagram of a network device according to an embodiment of the present application.

FIG. 11 is a schematic block diagram of a network device according to another embodiment of the present application.

FIG. 12 is a schematic block diagram of a communication device according to an embodiment of the present application.

FIG. 13 is a schematic block diagram of a chip according to an embodiment of the present application.

FIG. 14 is a schematic block diagram of a communication system according to an embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

The technical solutions of the embodiments of the present application can be applied to various communication systems, for example: a Global System of Mobile communication (GSM) system, a Code Division Multiple Access (CDMA) system, a wideband Code Division Multiple Access (CDMA) system (Wideband Code Division Multiple Access, WCDMA) system, General Packet Radio Service (General Packet Radio Service, GPRS), Long Term Evolution (Long Term Evolution, LTE) system, Advanced Long Term Evolution (Advanced long term evolution, LTE-A) system , New Radio (NR) system, evolution system of NR system, LTE (LTE-based access to unlicensed spectrum, LTE-U) system on unlicensed spectrum, NR (NR-based access to unlicensed spectrum) unlicensed spectrum, NR-U) system, Non-Terrestrial Networks (NTN) system, Universal Mobile Telecommunication System (UMTS), Wireless Local Area Networks (WLAN), Wireless Fidelity (Wireless Fidelity, WiFi), fifth-generation communication (5th-Generation, 5G) system or other communication systems, etc.

Generally speaking, traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, mobile communication systems will not only support traditional communication, but also support, for example, Device to Device (Device to Device, D2D) communication, Machine to Machine (M2M) communication, Machine Type Communication (MTC), Vehicle to Vehicle (V2V) communication, or Vehicle to everything (V2X) communication, etc. , the embodiments of the present application can also be applied to these communication systems.

Optionally, the communication system in this embodiment of the present application may be applied to a carrier aggregation (Carrier Aggregation, CA) scenario, a dual connectivity (Dual Connectivity, DC) scenario, or a standalone (Standalone, SA) distribution. web scene.

Optionally, the communication system in the embodiment of the present application may be applied to an unlicensed spectrum, where the unlicensed spectrum may also be considered as a shared spectrum; or, the communication system in the embodiment of the present application may also be applied to a licensed spectrum, where, Licensed spectrum can also be considered unshared spectrum.

The embodiments of the present application describe various embodiments in conjunction with network equipment and terminal equipment, where the terminal equipment may also be referred to as user equipment (User Equipment, UE), access terminal, subscriber unit, subscriber station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device, etc.

The terminal device can be a station (STAION, ST) in the WLAN, can be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a personal digital processing (Personal Digital Assistant, PDA) devices, handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, in-vehicle devices, wearable devices, next-generation communication systems such as end devices in NR networks, or future Terminal equipment in the evolved public land mobile network (Public Land Mobile Network, PLMN) network, etc.

In this embodiment of the present application, the terminal device can be deployed on land, including indoor or outdoor, handheld, wearable, or vehicle-mounted; it can also be deployed on water (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons, and satellites) superior).

In this embodiment of the present application, the terminal device may be a mobile phone (Mobile Phone), a tablet computer (Pad), a computer with a wireless transceiver function, a virtual reality (Virtual Reality, VR) terminal device, and an augmented reality (Augmented Reality, AR) terminal Equipment, wireless terminal equipment in industrial control, wireless terminal equipment in self driving, wireless terminal equipment in remote medical, wireless terminal equipment in smart grid , wireless terminal equipment in transportation safety, wireless terminal equipment in smart city or wireless terminal equipment in smart home, etc.

As an example and not a limitation, in this embodiment of the present application, the terminal device may also be a wearable device. Wearable devices can also be called wearable smart devices, which are the general term for the intelligent design of daily wear and the development of wearable devices using wearable technology, such as glasses, gloves, watches, clothing and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothing or accessories. Wearable device is not only a hardware device, but also realizes powerful functions through software support, data interaction, and cloud interaction. In a broad sense, wearable smart devices include full-featured, large-scale, complete or partial functions without relying on smart phones, such as smart watches or smart glasses, and only focus on a certain type of application function, which needs to cooperate with other devices such as smart phones. Use, such as all kinds of smart bracelets, smart jewelry, etc. for physical sign monitoring.

In this embodiment of the present application, the network device may be a device for communicating with a mobile device, and the network device may be an access point (Access Point, AP) in WLAN, or a base station (Base Transceiver Station, BTS) in GSM or CDMA , it can also be a base station (NodeB, NB) in WCDMA, it can also be an evolved base station (Evolutional Node B, eNB or eNodeB) in LTE, or a relay station or access point, or in-vehicle equipment, wearable devices and NR networks The network equipment (gNB) in the PLMN network in the future evolution or the network equipment in the NTN network, etc.

As an example and not a limitation, in this embodiment of the present application, the network device may have a mobile feature, for example, the network device may be a mobile device. Optionally, the network device may be a satellite or a balloon station. For example, the satellite may be a low earth orbit (LEO) satellite, a medium earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, a High Elliptical Orbit (HEO) ) satellite etc. Optionally, the network device may also be a base station set in a location such as land or water.

In this embodiment of the present application, a network device may provide services for a cell, and a terminal device communicates with the network device through transmission resources (for example, frequency domain resources, or spectrum resources) used by the cell, and the cell may be a network device ( For example, the cell corresponding to the base station), the cell can belong to the macro base station, or it can belong to the base station corresponding to the small cell (Small cell). Pico cell), Femto cell (Femto cell), etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

FIG. 1 exemplarily shows a communication system 100 . The communication system includes one network device 110 and two terminal devices 120 . Optionally, the communication system 100 may include multiple network devices 110, and the coverage of each network device 110 may include other numbers of terminal devices 120, which are not limited in this embodiment of the present application.

Optionally, the communication system 100 may further include other network entities such as a mobility management entity (Mobility Management Entity, MME), an access and mobility management function (Access and Mobility Management Function, AMF), to which the embodiments of the present application Not limited.

Wherein, the network equipment may further include access network equipment and core network equipment. That is, the wireless communication system further includes a plurality of core networks for communicating with the access network equipment. The access network equipment may be a long-term evolution (long-term evolution, LTE) system, a next-generation (mobile communication system) (next radio, NR) system, or an authorized auxiliary access long-term evolution (authorized auxiliary access long-term evolution, LAA- The evolved base station (evolutional node B, may be referred to as eNB or e-NodeB for short) in the LTE) system is a macro base station, a micro base station (also called a "small base station"), a pico base station, an access point (AP), Transmission site (transmission point, TP) or new generation base station (new generation Node B, gNodeB), etc.

It should be understood that, in the embodiments of the present application, a device having a communication function in the network/system may be referred to as a communication device. Taking the communication system shown in FIG. 1 as an example, the communication device may include a network device and a terminal device with a communication function, and the network device and the terminal device may be specific devices in this embodiment of the application, which will not be repeated here; It may include other devices in the communication system, for example, other network entities such as a network controller and a mobility management entity, which are not limited in this embodiment of the present application.

It should be understood that the terms "system" and "network" are often used interchangeably herein. The term "and/or" in this article is only an association relationship to describe the associated objects, indicating that there can be three kinds of relationships, for example, A and/or B, it can mean that A exists alone, A and B exist at the same time, and A and B exist independently B these three cases. In addition, the character "/" in this document generally indicates that the related objects are an "or" relationship.

It should be understood that the "instruction" mentioned in the embodiments of the present application may be a direct instruction, an indirect instruction, or an associated relationship. For example, if A indicates B, it can indicate that A directly indicates B, for example, B can be obtained through A; it can also indicate that A indicates B indirectly, such as A indicates C, and B can be obtained through C; it can also indicate that there is an association between A and B relation.

In the description of the embodiments of the present application, the term "corresponding" may indicate that there is a direct or indirect corresponding relationship between the two, or may indicate that there is an associated relationship between the two, or indicate and be instructed, configure and be instructed configuration, etc.

In order to facilitate the understanding of the technical solutions of the embodiments of the present application, the related technologies of the embodiments of the present application are described below. The following related technologies can be arbitrarily combined with the technical solutions of the embodiments of the present application as optional solutions, which all belong to the embodiments of the present application. protected range.

FIG. 2 exemplarily shows the 5G network system architecture. Among them, the UE connects with the access network (AN, Access Network) through the Uu wireless interface, and exchanges access stratum messages and wireless data transmission. The UE communicates with the access and mobility management functions (AMF, Access and Mobility Management Function) to connect to the non-access stratum (NAS, None Access Stratum) and exchange NAS messages. The AMF is responsible for the access and mobility management network elements in the core network, and the session management function (SMF, Session Management Function) is responsible for the session management network elements in the core network. In addition to the mobility management of the UE, the AMF is also responsible for the Forwarding of session management related messages between UE and SMF. The Policy Control Function (PCF, Policy Control Function) is a policy management function in the core network, and is responsible for formulating policies related to mobility management, session management, and charging of the UE. The User Plane Function (UPF, User Plane Function) is the user plane function in the core network. It transmits data to the external data network through the N6 interface, and transmits data to the AN (or RAN) through the N3 interface.

After the UE accesses the 5G network through the Uu port, it transmits service data through the network. When the service is initiated, the network layer of the UE obtains the QoS requirements of the service from the upper layer (such as the operating system or application), and the UE converts the QoS requirements of the service into the QoS parameters of the Uu interface, and passes the corresponding correspondence between the UE and the UPF under the control of the SMF QoS flow for data transmission.

In a network slicing application scenario, the UE places the requested S-NSSAI in the requested (Requested) NSSAI according to the service, and the Requested NSSAI is included in the registration request (Registration request) and sent to the AMF. The AMF determines the allowed (Allowed) NSSAI according to the scope of the UE subscription and network slice deployment, and sends it to the UE in the Registration accept message, or to the base station RAN (Radio Access) in the message (message) of the N2 interface. Network, wireless access network).

After the UE receives the allowed NSSAI, it needs to establish a PDU session in the slice in the allowed NSSAI. Data can be sent and received only after the PDU session is established.

When the network is deployed, the coverage of each slice may be different. When the AMF decides the allowed NSSAI, it needs to ensure that all slices in the allowed NSSAI can be covered by the Registration area (RA) allocated by the AMF to the UE. For example, the RA may be a tracking area list (TA list) consisting of one or more TAs. The AMF obtains the S-NSSAI supported by the base station and the corresponding Tracking Area (TA) from the base station through NG setup request (setup request) or RAN configuration update (configuration update) signaling.

As shown in the following table, it is an example for the base station to notify the AMF of the slice information currently supported by itself.

Exemplarily, in an application scenario, base stations in different areas may support different network slices. As shown in FIG. 3 , the RA of a certain area and the UE may not completely overlap. Cell 1 supports slice 1, and cell 2 supports slice 2. When the UE moves from cell 1 to cell 2, since cell 2 does not support slice 1, slice 1 can be mapped to slice 2, and slice 2 is used to serve the UE to ensure service continuity.

Illustratively, Service and Session Continuity (SSC) may include multiple modes. For example SSC mode 1, 2, 3. Among them, SSC mode 1 may mean that the anchor (Anchor) UPF used by the PDU session (session) remains unchanged, and the PDU address such as the Internet Protocol (Internet Protocol, IP) address remains unchanged; SSC mode 2 may mean that the old PDU session is released first. If a new PDU session is established, the Anchor UPF will change, and the PDU address will change; SSC mode 3 can mean that a new PDU session is established first, and then the old PDU session is released, the Anchor UPF will change, and the PDU address will change. SSC mode 2 and 3 can achieve business continuity through the PDU layer, such as the Transmission Control Protocol (TCP, Transmission Control Protocol) layer protocol, so that users cannot perceive business interruption. In the embodiments of the present application, different service continuity can be guaranteed for the above scenarios.

FIG. 4 is a schematic flowchart of a session management method 200 according to an embodiment of the present application. The method can optionally be applied to, but not limited to, the systems shown in, for example, Figures 1, 2, and 3 . The method includes at least some of the following.

S210. When the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information, the terminal device receives the second slice information supported by the second cell.

S220. The terminal device releases the session using the first slice information.

S230. The terminal device uses the second slice information to establish a session.

Exemplarily, when the terminal device is in the first cell, a registration process is performed to obtain permitted slice information, such as first slice information, and a PDU session can be established using the first slice information supported by the first cell. If the terminal device leaves the first cell and enters the second cell, a handover process between the first access network device corresponding to the first cell and the second access network device corresponding to the second cell may be triggered. Wherein, if the second cell does not support the first slice information, the PDU session established by the terminal device using the first slice information cannot be successfully handed over to the second access network device. During the handover process or after the handover is completed, the first access network device or the second access network device may notify the first core network device such as the AMF that the session is not successfully handed over. The notification may also carry the mapping relationship between the first slice information and the second slice information; and/or the second slice information and a mapping indication. If the AMF knows the mapping relationship between the first slice information and the second slice information, for example, the mapping relationship is preconfigured on the AMF, the above information may not be carried in the notification.

If the second cell supports the second slice information, the terminal device may receive the second handover information. Then, the terminal device may release the PDU session of the first slice information locally, and establish the PDU session using the second slice information.

Optionally, the first slice information and the second slice information have a mapping relationship.

Optionally, the method further includes:

When the terminal device moves to the second cell, the terminal device acquires slice information supported by the access network device from a system message broadcast by the access network device corresponding to the second cell.

Exemplarily, if the first access network device corresponding to the first cell is the original base station, and the second access network device corresponding to the second cell is the target base station, and the terminal device moves to the second cell, it can start from the second cell. The slice information supported by the target base station is obtained from the system message broadcast by the target corresponding to the cell.

Optionally, the method further includes:

The radio resource control (Radio Resource Control, RRC) layer of the terminal device transmits the slice information supported by the access network device to the non-access stratum (Non-Access-Stratum, NAS) layer of the terminal device, so that in the The NAS layer determines whether the first slice information is available.

Optionally, the terminal device releases the session using the first slice information, further comprising:

The terminal device receives the PDU session release command sent by the network, or, in the case of determining that the first slice information is unavailable, the terminal device locally releases the PDU session using the first slice information.

Optionally, after the handover process is completed, the terminal device executes a new registration process under the condition that the triggering condition of the registration process is satisfied.

Optionally, the trigger condition includes at least one of the following:

The terminal device leaves the registration area;

The first core network equipment such as AMF changes;

The terminal device finds that the second cell does not support the allowed NSSAI saved for the registered PLMN.

For example, after the handover is completed, the terminal device leaves the previously obtained registration area, which can trigger the registration process. For another example, if the AMF of the cell entered by the terminal device changes, the registration process can be triggered. In addition, if the terminal device obtains the slice information supported by the target base station from the system message broadcast by the target corresponding to the second cell, and then finds that the second cell does not support the allowed NSSAI saved for the registered PLMN. There are various conditions for triggering the registration process, which are not specifically limited in this embodiment of the present application.

Optionally, in the registration process, the terminal device sends a registration request, where the registration request is used to instruct the first core network device such as the AMF to release the PDU session using the first slice information.

Optionally, the registration request does not include the requested first slice information.

Exemplarily, the terminal device sends a registration request to the AMF through the access network device, and the registration request may not include the first slice information. After receiving the registration request, the AMF determines that the first slice information is no longer requested by the terminal device, and can trigger The SMF releases the PDU session using the first slice information. The registration request may also include the first slice information. The AMF can obtain the current cell of the terminal device or the current TA does not support the first slice information in other ways, and can trigger the SMF to release the PDU session using the first slice information. .

Optionally, the AMF may notify the SMF that the PDU session using the first slice information needs to be released. For example, the AMF sends a session release message to the SMF, where the session release message includes the identifier of the PDU session that needs to be released. After receiving the session release message, the SMF can release the session corresponding to the identifier of the PDU session, that is, the PDU session using the first slice information.

Optionally, the session release message may also include at least one of the following:

the mapping relationship between the first slice information and the second slice information;

The second slice information and the mapping indication.

Optionally, in one manner, the second slice information received by the terminal device is carried by a first NAS message, and the first NAS message is obtained by the first core network device and the second slice information from the second slice information. The second NAS message of the core network device is sent to the terminal device.

Optionally, the first core network device is an access and mobility management network element AMF, and the second core network device is a session management network element SMF.

Optionally, the second NAS message includes the second slice information.

Optionally, the second NAS message is a PDU session release command.

Exemplarily, after the SMF decides to release the PDU session, a second NAS message may be sent to the AMF, and the second NAS message may include an identifier of the PDU session and the like. If the SMF knows the mapping relationship between the first slice information and the second slice information, or the second slice information and the mapping indication, the second NAS message may further include the second slice information. Then the AMF may send the first NAS message to the terminal device through the first access network device or the second access network device, and send the second slice information to the terminal device.

Optionally, in another manner, the second slice information received by the terminal device is carried by a registration accept message, where the registration accept message includes at least one of the following:

The first slice information is mapped to the second slice information;

The allowed slice information is the second slice information.

Optionally, in this manner, the access network device may notify the AMF of the mapping relationship between the first slice information and the second slice information before the terminal device performs a new registration process. For example, before the terminal device performs the initial registration process, the access network device notifies the AMF of the mapping relationship between the first slice information and the second slice information. For another example, during the handover process or after the handover is completed, the access network device notifies the AMF of the mapping relationship between the first slice information and the second slice information.

Optionally, the first slice information and/or the second slice information is the single network slice selection assistance information S-NSSAI.

For example, the first slice information is S-NSSAI 1, the second handover information is S-NSSAI 2, the first cell and its corresponding first access network equipment support S-NSSAI 1, and the second cell and its corresponding first access network equipment support S-NSSAI 1. The second access network equipment does not support S-NSSAI 1 but supports S-NSSAI 2. In the case where the terminal device leaves the first cell and enters the second cell, the terminal device receives S-NSSAI 2. The terminal device releases the PDU session using S-NSSAI 1 and establishes a PDU session using S-NSSAI 2.

FIG. 5 is a schematic flowchart of a session management method 300 according to an embodiment of the present application. The method can optionally be applied to, but not limited to, the systems shown in, for example, Figures 1, 2, and 3 . The method includes at least some of the following.

S310. When the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information, the network device sends the second slice information supported by the second cell to the terminal device.

Optionally, the network device in this embodiment may be a first core network device such as an AMF, and for details, refer to the relevant description about the first core network device in the foregoing embodiment.

Optionally, the method further includes:

The network device receives a notification from the access network device, and the notification includes that the PDU session established using the first slice information in the handover procedure cannot be successfully handed over. For example, the first core network device AMF receives a notification from the original base station or the target base station to know that the PDU session established using the first slice information in the handover process cannot be successfully handed over from the original base station to the target base station.

Optionally, the notification includes at least one of the following:

the mapping relationship between the first slice information and the second slice information;

The second slice information and the mapping indication.

Optionally, the method further includes:

The network device receives the mapping relationship between the first slice information and the second slice information from the access network device. For example, the first core network device AMF receives the mapping relationship between the first slice information and the second slice information from the original base station or the target base station.

Optionally, the method further includes:

The network device sends a session release message to the core network device, where the session release message includes an identifier of the PDU session to be released, and the session release message is used to instruct the core network device to release the PDU session using the first slice information.

Optionally, the core network device such as the second core network device is an SMF.

Exemplarily, the first core network device such as the AMF sends a session release message to the second core network device such as the SMF.

Optionally, the session release message includes at least one of the following:

the mapping relationship between the first slice information and the second slice information;

The second slice information and the mapping indication.

Optionally, the method further includes: the network device receiving a second NAS message from the core network device. For example, the first core network device AMF receives the SMF second NAS message from the second core network device.

Optionally, the second NAS message includes the second slice information.

Optionally, the second NAS message is a PDU session release command.

Optionally, the method further includes:

The network device encapsulates the second slice information and the second NAS message to obtain a first NAS message.

Optionally, the method further includes: the network device sending the first NAS message to the terminal device. For example, the first core network device sends the first NAS message to the terminal device through the access network device.

Optionally, the method further includes:

The network device sends a registration acceptance message to the terminal device, where the registration acceptance message includes at least one of the following:

The first slice information is mapped to the second slice information;

The allowed slice information is the second slice information.

For example, the first core network device sends the above-mentioned registration acceptance message to the terminal device through the access network device.

Optionally, the first slice information and/or the second slice information is S-NSSAI.

For a specific example of the network device executing method 300 in this embodiment, reference may be made to the relevant description of the network device such as the AMF in the foregoing method 200, which is not repeated here for brevity.

Example one:

As shown in FIG. 6, it is a session management method that can maintain business continuity, which may specifically include the following steps:

S10. The UE performs a registration (Registration) process to obtain an allowed (Allowed) NSSAI. The UE establishes a PDU session (PDU session establishment for S-NSSAI 1) according to the S-NSSAI 1 corresponding to the service.

S11. When the UE wants to leave the cell that supports S-NSSAI 1, and the next cell does not support S-NSSAI 1, the RAN, such as the source base station and the target base station, first performs the handover process, and the PDU session using S-NSSAI 1 cannot be used. Switch past.

During the handover process or after the handover is completed, the original base station or the target base station may notify the AMF that the session has not been handed over successfully. Optionally, the RAN may send an N2 MM message (a mobility management message sent through the N2 interface) to the AMF, and the message may carry the PDU session ID. Optionally, the N2 MM message may also carry the mapping relationship between S-NSSAI 1 and S-NSSAI 2 (S-NSSAI 1 mapped to S-NSSAI 2), or may carry S-NSSAI 2 and a mapping indication. In addition, if the AMF knows that S-NSSAI 1 is mapped to S-NSSAI 2, the N2 MM message may not carry the mapping relationship between S-NSSAI 1 and S-NSSAI 2 (S-NSSAI 1 mapped to S-NSSAI 2), or Can carry S-NSSAI 2 and mapping indication.

After the UE moves to a new cell, if the RRC layer of the UE obtains the slices supported by the base station in the system information broadcast by the base station and transmits it to the NAS layer of the UE, the NAS layer can know that the base station does not support S-NSSAI 1. The UE may release the PDU session using S-NSSAI 1 locally.

After the handover is completed, if the UE leaves the previously obtained Registration Area (RA), the UE can initiate a registration process. Optionally, if the NAS layer knows that the base station does not support S-NSSAI 1, the registration request may not carry S-NSSAI 1. Since the registration request does not carry the S-NSSAI 1, the AMF determines that the S-NSSAI 1 is no longer requested by the UE after receiving the registration request, and can trigger the SMF to release the PDU session using the S-NSSAI 1.

S12. The AMF informs the SMF that the PDU session of the S-NSSAI 1 needs to be released, carrying the PDU session identifier (Identifier, ID). Optionally, the AMF may send an SM content release (context release) message to the SMF, and the message may carry the PDU session ID, and may also carry the mapping relationship between S-NSSAI 1 and S-NSSAI 2, or may carry S-NSSAI 2 and mapping instructions. However, if the isolation of network slicing is considered, the above information may not be sent to SMF.

S13. The SMF initiates a PDU session release, for example, sends the PDU session ID to the AMF through N1N2 message transfer (N1N2 msg transfer). Optionally, the SMF sends a NAS message to the AMF, where the NAS message may be a PDU session release command (session release command). For example, the NAS message may be a PDU session release command, which may include a session ID (session ID), a reactivation request (reactivation required), etc., and optionally, may also include S-NSSAI 2. If the SMF does not know the mapping relationship between S-NSSAI 1 and S-NSSAI 2, it may not carry S-NSSAI 2 in this step.

S14 and S15, the AMF sends an N2 MM message to the RAN. For example, the AMF encapsulates the PDU session release command, the session identifier and the slice information that needs to create a new PDU session in a NAS message and sends it to the UE through the base station. The session identifier may be carried in the encapsulated NAS message. Optionally, the NAS message may also carry S-NSSAI 2. Optionally, the NAS message may also carry a PDU session release command. The PDU session release command may include a session ID (session ID), a reactivation request (reactivation required), etc., and optionally, may also include S-NSSAI 2.

S16, the UE releases the old PDU session, and uses S-NSSAI 2 to establish a new PDU session.

Optionally, the above-mentioned base station may be an original base station or a target base station.

Optionally, the AMF may change in the above process. For example, if the above process includes two AMFs, the AMF in S12 and S13 is the source AMF, the source AMF can transfer the information received in S13 to the target AMF, and the target AMF continues to execute S14.

In this embodiment, the AMF can send the slice information supported by the target base station to the UE through the RAN to ensure service continuity, especially the service continuity of SSC mode 2.

Example two:

As shown in FIG. 7 , it is a session management method that can maintain business continuity, which may specifically include the following steps:

S20, the RAN, for example, the base station notifies the AMF of the mapping relationship between S-NSSAI 1 and S-NSSAI 2 (S-NSSAI 1 mapped to S-NSSAI 2). For example, the base station sends an N2 MM message to the AMF, and the message includes the mapping relationship between S-NSSAI 1 and S-NSSAI2. The specific execution sequence of this step is not limited in this example. For example, before S23, the base station may notify the AMF of the mapping relationship between S-NSSAI 1 and S-NSSAI 2.

S21. The UE first performs a registration (Registration) process to obtain an allowed (Allowed) NSSAI. The UE establishes a PDU session (PDU session establishment for S-NSSAI 1) according to the S-NSSAI 1 corresponding to the service.

S22. When the UE wants to leave the cell that supports S-NSSAI 1 and the next cell does not support S-NSSAI 1, the source base station and the target base station first perform a handover (Handover) process, and the PDU session using S-NSSAI 1 cannot be handed over. .

S23. After the handover is completed, the UE performs a registration (Registration) process, and the UE sends a registration request (Registration request) to the AMF, which optionally carries the requested slice information Requested NSSAI={S-NSSAI 1}. If the RRC layer of the UE obtains the slices supported by the base station in the system information broadcast by the base station, and then transmits it to the NAS layer of the UE, the NAS layer knows that the base station does not support S-NSSAI 1. The UE may not carry S-NSSAI 1. If the UE does not carry S-NSSAI, the UE may locally release the PDU session using S-NSSAI 1.

After receiving the registration request (Registration request), the AMF determines that there is a PDU session using S-NSSAI 1, and S-NSSAI 1 is mapped to S-NSSAI 2.

S24. The AMF notifies the SMF in the S-NSSAI 1 to release the PDU session. For example, the AMF sends a session release message to the SMF, and the session release message includes a session ID (Session ID) that needs to be released.

S25. The AMF maps S-NSSAI 1 to S-NSSAI 2, and puts the allowed slice information allowed NSSAI={S-NSSAI 2} in a Registration accept message and sends it to the UE.

S26. After receiving the mapping from S-NSSAI 1 to S-NSSAI 2, the UE uses S-NSSAI 2 to establish a PDU session. Optionally, if the UE does not release the PDU session in S23, the old PDU session may be released in this step, and the establishment of the PDU session using S-NSSAI 2 is initiated.

Optionally, the above-mentioned base station may be an original base station or a target base station.

Optionally, the AMF may change in the above process. If there are two AMFs, the AMF in S23 and S25 is the new AMF, and the AMF in S24 is the old AMF.

In this embodiment, the RAN may send the mapping relationship between S-NSSAI 1 and S-NSSAI 2 to the AMF. The AMF can send the slice information supported by the target base station to the UE through the RAN to ensure service continuity, especially the service continuity of SSC mode2.

FIG. 8 is a schematic block diagram of a terminal device 400 according to an embodiment of the present application. The terminal device 400 may include:

A receiving unit 410, configured to receive the second slice information supported by the second cell when the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information;

a release unit 420, configured to release the session using the first slice information;

The establishing unit 430 is configured to establish a session by using the second slice information.

Optionally, the first slice information and the second slice information have a mapping relationship.

Optionally, as shown in Figure 9, the terminal device further includes:

The obtaining unit 440 is configured to obtain slice information supported by the access network device from a system message broadcast by the access network device corresponding to the second cell when the terminal device moves to the second cell.

Optionally, the terminal device further includes:

The determining unit 450 is configured to transmit the slice information supported by the access network device to the non-access stratum NAS layer through the RRC layer, so as to determine whether the first slice information is available (available) at the NAS layer.

Optionally, the releasing unit is further configured to release the PDU session using the first slice information locally when it is determined that the first slice information is unavailable.

Optionally, the second slice information received by the terminal device is carried by a first NAS message, and the first NAS message is a combination of the second slice information and the second slice information from the second core network device by the first core network device. NAS messages are sent to the terminal device.

Optionally, the second NAS message includes the second slice information.

Optionally, the second NAS message is a PDU session release command.

Optionally, the first core network device is an access and mobility management network element AMF, and the second core network device is a session management network element SMF.

Optionally, the second slice information received by the terminal device is carried by a registration accept message, where the registration accept message includes at least one of the following:

The first slice information is mapped to the second slice information;

The allowed slice information is the second slice information.

Optionally, the first slice information and/or the second slice information is the single network slice selection assistance information S-NSSAI.

The terminal device 400 in this embodiment of the present application can implement the corresponding functions of the terminal device in the foregoing method embodiments. For the corresponding processes, functions, implementations, and beneficial effects of each module (submodule, unit, or component, etc.) in the terminal device 400, reference may be made to the corresponding descriptions in the foregoing method embodiments, which are not repeated here. It should be noted that the functions described by each module (submodule, unit, or component, etc.) in the terminal device 400 of the application embodiment may be implemented by different modules (submodule, unit, or component, etc.), or may be implemented by the same module Module (submodule, unit or component, etc.) implementation.

FIG. 10 is a schematic block diagram of a network device 500 according to an embodiment of the present application. The network device 500 may include:

The sending unit 510 is configured to send a second slice supported by the second cell to the terminal device when the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information information.

Optionally, as shown in Figure 11, the network device further includes:

The first receiving unit 520 is configured to receive a notification from the access network device, where the notification includes that the PDU session established by using the first slice information in the handover procedure cannot be successfully handed over.

Optionally, the notification includes at least one of the following:

the mapping relationship between the first slice information and the second slice information;

The second slice information and the mapping indication.

Optionally, the network device further includes:

The second receiving unit 530 is configured to receive the mapping relationship between the first slice information and the second slice information from the access network device.

Optionally, the network device further includes:

The sending unit is further configured to send a session release message to the core network device, where the session release message includes an identifier of the PDU session to be released, and the session release message is used to instruct the second core network device to release the PDU using the first slice information session.

Optionally, the session release message includes at least one of the following:

the mapping relationship between the first slice information and the second slice information;

The second slice information and the mapping indication.

Optionally, the network device further includes:

The third receiving unit 540 is configured to receive the second NAS message from the core network device.

Optionally, the second NAS message includes the second slice information.

Optionally, the second NAS message is a PDU session release command.

Optionally, the network device further includes:

The encapsulation unit 550 is configured to encapsulate the second slice information and the second NAS message to obtain a first NAS message.

Optionally, the sending unit is further configured to send the first NAS message to the terminal device.

Optionally, the sending unit is further configured to send a registration acceptance message to the terminal device, where the registration acceptance message includes at least one of the following:

The first slice information is mapped to the second slice information;

The allowed slice information is the second slice information.

Optionally, the network device is AMF.

Optionally, the core network device is an SMF.

Optionally, the first slice information and/or the second slice information is S-NSSAI.

The network device 500 in this embodiment of the present application can implement the corresponding functions of the network device in the foregoing method embodiments. For the corresponding processes, functions, implementations, and beneficial effects of each module (submodule, unit, or component, etc.) in the network device 500, reference may be made to the corresponding descriptions in the foregoing method embodiments, which will not be repeated here. It should be noted that the functions described by each module (submodule, unit, or component, etc.) in the network device 500 of the application embodiment may be implemented by different modules (submodule, unit, or component, etc.), or may be implemented by the same module Module (submodule, unit or component, etc.) implementation.

FIG. 12 is a schematic structural diagram of a communication device 600 according to an embodiment of the present application. The communication device 600 includes a processor 610, and the processor 610 can call and run a computer program from a memory, so that the communication device 600 implements the methods in the embodiments of the present application.

Optionally, the communication device 600 may also include a memory 620 . The processor 610 may call and run a computer program from the memory 620, so that the communication device 600 implements the methods in the embodiments of the present application.

The memory 620 may be a separate device independent of the processor 610 , or may be integrated in the processor 610 .

Optionally, the communication device 600 may further include a transceiver 630, and the processor 610 may control the transceiver 630 to communicate with other devices, specifically, may send information or data to other devices, or receive information or data sent by other devices .

Among them, the transceiver 630 may include a transmitter and a receiver. The transceiver 630 may further include antennas, and the number of the antennas may be one or more.

Optionally, the communication device 600 may be the network device of this embodiment of the present application, and the communication device 600 may implement the corresponding processes implemented by the network device in each method of the embodiment of the present application, which is not repeated here for brevity.

Optionally, the communication device 600 may be a terminal device in this embodiment of the present application, and the communication device 600 may implement corresponding processes implemented by the terminal device in each method in the embodiment of the present application, which is not repeated here for brevity.

FIG. 13 is a schematic structural diagram of a chip 700 according to an embodiment of the present application. The chip 700 includes a processor 710, and the processor 710 can call and run a computer program from a memory, so as to implement the methods in the embodiments of the present application.

Optionally, the chip 700 may further include a memory 720 . The processor 710 may call and run a computer program from the memory 720 to implement the method executed by the terminal device or the network device in the embodiment of the present application.

The memory 720 may be a separate device independent of the processor 710 , or may be integrated in the processor 710 .

Optionally, the chip 700 may further include an input interface 730 . The processor 710 may control the input interface 730 to communicate with other devices or chips, and specifically, may acquire information or data sent by other devices or chips.

Optionally, the chip 700 may further include an output interface 740 . The processor 710 can control the output interface 740 to communicate with other devices or chips, and specifically, can output information or data to other devices or chips.

Optionally, the chip can be applied to the network device in the embodiment of the present application, and the chip can implement the corresponding processes implemented by the network device in each method of the embodiment of the present application, which is not repeated here for brevity.

Optionally, the chip can be applied to the terminal device in the embodiment of the present application, and the chip can implement the corresponding processes implemented by the terminal device in each method of the embodiment of the present application, which is not repeated here for brevity.

Chips applied to network equipment and terminal equipment can be the same chip or different chips.

It should be understood that the chip mentioned in the embodiments of the present application may also be referred to as a system-on-chip, a system-on-chip, a system-on-chip, or a system-on-a-chip, or the like.

The processor mentioned above may be a general-purpose processor, a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC) or Other programmable logic devices, transistor logic devices, discrete hardware components, etc. The general-purpose processor mentioned above may be a microprocessor or any conventional processor or the like.

The memory mentioned above may be either volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically programmable Erase programmable read-only memory (electrically EPROM, EEPROM) or flash memory. Volatile memory may be random access memory (RAM).

It should be understood that the above memory is an example but not a limitative description, for example, the memory in the embodiment of the present application may also be a static random access memory (static RAM, SRAM), a dynamic random access memory (dynamic RAM, DRAM), Synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchronous connection Dynamic random access memory (synch link DRAM, SLDRAM) and direct memory bus random access memory (Direct Rambus RAM, DR RAM) and so on. That is, the memory in the embodiments of the present application is intended to include but not limited to these and any other suitable types of memory.

FIG. 14 is a schematic block diagram of a communication system 800 according to an embodiment of the present application. The communication system 800 includes a terminal device 810 and a network device 820 .

The terminal device 810 is configured to receive the second slice information supported by the second cell when the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information; release; A session using the first slice information; establishing a session using the second slice information.

The network device 820 is configured to send the second slice supported by the second cell to the terminal device when the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information information.

The terminal device 810 can be used to implement the corresponding functions implemented by the terminal device in the above method, and the network device 820 can be used to implement the corresponding functions implemented by the network device such as the first core network device AMF in the above method. For brevity, details are not repeated here.

Optionally, the communication system may further include a second core network device, and for details, refer to the corresponding function implemented by the SMF in the above method. Optionally, the communication system may further include access network devices such as a first access network device and/or a second access network device. For details, refer to the corresponding functions implemented by the first access network device and/or the second access network device in the above method. For brevity, details are not repeated here.

In the above-mentioned embodiments, it may be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented in software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions according to the embodiments of the present application are generated in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable device. The computer instructions may be stored on or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be transmitted over a wire from a website site, computer, server or data center (eg coaxial cable, optical fiber, Digital Subscriber Line (DSL)) or wireless (eg infrared, wireless, microwave, etc.) means to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a Solid State Disk (SSD)), and the like.

It should be understood that, in various embodiments of the present application, the size of the sequence numbers of the above-mentioned processes does not mean the sequence of execution, and the execution sequence of each process should be determined by its functions and internal logic, and should not be dealt with in the embodiments of the present application. implementation constitutes any limitation.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described systems, devices and units may refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art who is familiar with the technical scope disclosed in the present application can easily think of changes or substitutions. Covered within the scope of protection of this application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (62)

1. A session management method, comprising:

   In the case that the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information, the terminal device receives the second slice information supported by the second cell;

   releasing, by the terminal device, the session using the first slice information;

   The terminal device establishes a session using the second slice information.
2. The method of claim 1, wherein the first slice information and the second slice information have a mapping relationship.
3. The method of claim 1, wherein the method further comprises:

   When the terminal device moves to the second cell, the terminal device acquires slice information supported by the access network device from a system message broadcast by the access network device corresponding to the second cell.
4. The method of claim 3, wherein the method further comprises:

   The radio resource control RRC layer of the terminal device transmits the slice information supported by the access network device to the non-access stratum NAS layer of the terminal device, so as to determine the first slice information at the NAS layer Whether it is available (available).
5. The method according to claim 4, wherein the terminal device releases the session using the first slice information, further comprising:

   If it is determined that the first slice information is unavailable, the terminal device locally releases the PDU session using the first slice information.
6. The method according to any one of claims 1 to 5, wherein the second slice information received by the terminal device is carried by a first NAS message, and the first NAS message is sent by a first core network device sending the second slice information and the second NAS message from the second core network device to the terminal device.
7. The method of claim 6, wherein the second slice information is included in the second NAS message.
8. The method according to claim 6 or 7, wherein the second NAS message is a PDU session release command.
9. The method according to any one of claims 6 to 8, wherein the first core network device is an access and mobility management network element AMF, and the second core network device is a session management network element SMF.
10. The method according to any one of claims 1 to 9, wherein the second slice information received by the terminal device is carried by a registration accept message, and the registration accept message includes at least one of the following:

    the first slice information is mapped to the second slice information;

    The allowed slice information is the second slice information.
11. The method according to any one of claims 1 to 10, wherein the first slice information and/or the second slice information is single network slice selection assistance information S-NSSAI.
12. A session management method, comprising:

    When the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information, the network device sends the second slice information supported by the second cell to the terminal device.
13. The method of claim 12, wherein the method further comprises:

    The network device receives a notification from the access network device, where the notification includes that the PDU session established by using the first slice information in the handover procedure cannot be successfully handed over.
14. The method of claim 13, wherein the notification includes at least one of the following:

    the mapping relationship between the first slice information and the second slice information;

    The second slice information and the mapping indication.
15. The method of any one of claims 12 to 14, wherein the method further comprises:

    The network device receives the mapping relationship between the first slice information and the second slice information from the access network device.
16. The method of any one of claims 12 to 15, wherein the method further comprises:

    The network device sends a session release message to the core network device, where the session release message includes an identifier of the PDU session to be released, and the session release message is used to instruct the core network device to release the PDU session using the first slice information.
17. The method according to claim 16, wherein the session release message includes at least one of the following:

    the mapping relationship between the first slice information and the second slice information;

    The second slice information and the mapping indication.
18. The method of claim 16 or 17, wherein the method further comprises:

    The network device receives the second NAS message from the core network device.
19. 19. The method of claim 18, wherein the second NAS message includes the second slice information.
20. The method of claim 18 or 19, wherein the second NAS message is a PDU session release command.
21. The method of any one of claims 18 to 20, wherein the method further comprises:

    The network device encapsulates the second slice information and the second NAS message to obtain a first NAS message.
22. The method of claim 21, wherein the method further comprises:

    The network device sends the first NAS message to the terminal device.
23. The method of claim 22, wherein the method further comprises:

    The network device sends a registration acceptance message to the terminal device, where the registration acceptance message includes at least one of the following:

    the first slice information is mapped to the second slice information;

    The allowed slice information is the second slice information.
24. The method of any one of claims 12 to 23, wherein the network device is an AMF.
25. The method according to any one of claims 16 to 23, wherein the core network device is an SMF.
26. The method according to any one of claims 12 to 25, wherein the first slice information and/or the second slice information is S-NSSAI.
27. A terminal device including:

    a receiving unit, configured to receive the second slice information supported by the second cell when the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information;

    a release unit, configured to release the session using the first slice information;

    an establishment unit, configured to establish a session by using the second slice information.
28. The terminal device according to claim 27, wherein the first slice information and the second slice information have a mapping relationship.
29. The terminal device according to claim 27, wherein the terminal device further comprises:

    an obtaining unit, configured to obtain slice information supported by the access network device from a system message broadcast by the access network device corresponding to the second cell when the terminal device moves to the second cell .
30. The terminal device according to claim 29, wherein the terminal device further comprises:

    a determining unit, configured to transmit the slice information supported by the access network device to the non-access stratum NAS layer through the radio resource control RRC layer, so as to determine at the NAS layer whether the first slice information is available (available ).
31. The terminal device according to claim 30, wherein the releasing unit is further configured to release the PDU session using the first slice information locally in the case that the first slice information is determined to be unavailable.
32. The terminal device according to any one of claims 27 to 31, wherein the second slice information received by the terminal device is carried by a first NAS message, and the first NAS message is sent by the first core network The device sends the second slice information and the second NAS message from the second core network device to the terminal device.
33. The terminal device according to claim 32, wherein the second slice information is included in the second NAS message.
34. The terminal device according to claim 32 or 33, wherein the second NAS message is a PDU session release command.
35. The terminal device according to any one of claims 32 to 34, wherein the first core network device is an access and mobility management network element AMF, and the second core network device is a session management network element SMF.
36. The terminal device according to any one of claims 27 to 35, wherein the second slice information received by the terminal device is carried by a registration accept message, and the registration accept message includes at least one of the following:

    the first slice information is mapped to the second slice information;

    The allowed slice information is the second slice information.
37. The terminal device according to any one of claims 27 to 36, wherein the first slice information and/or the second slice information is single network slice selection assistance information S-NSSAI.
38. A network device comprising:

    A sending unit, configured to send the second cell supported by the second cell to the terminal device when the terminal device leaves the first cell that supports the first slice information and enters the second cell that does not support the first slice information Slice information.
39. The network device of claim 38, wherein the network device further comprises:

    A first receiving unit, configured to receive a notification from an access network device, where the notification includes that the PDU session established by using the first slice information in the handover procedure cannot be successfully handed over.
40. The network device of claim 39, wherein the notification includes at least one of the following:

    the mapping relationship between the first slice information and the second slice information;

    The second slice information and the mapping indication.
41. The network device according to any one of claims 38 to 40, wherein the network device further comprises:

    The second receiving unit is configured to receive the mapping relationship between the first slice information and the second slice information from the access network device.
42. The network device according to any one of claims 38 to 41, wherein the network device further comprises:

    The sending unit is further configured to send a session release message to the core network device, where the session release message includes an identifier of the PDU session that needs to be released, and the session release message is used to instruct the second core network device to release and use the first slice information on the PDU session.
43. The network device according to claim 42, wherein the session release message includes at least one of the following:

    the mapping relationship between the first slice information and the second slice information;

    The second slice information and the mapping indication.
44. The network device according to claim 42 or 43, wherein the network device further comprises:

    The third receiving unit is configured to receive the second NAS message from the core network device.
45. The network device of claim 44, wherein the second NAS message includes the second slice information.
46. The network device according to claim 44 or 45, wherein the second NAS message is a PDU session release command.
47. The network device according to any one of claims 44 to 46, wherein the network device further comprises:

    An encapsulation unit, configured to encapsulate the second slice information and the second NAS message to obtain a first NAS message.
48. The network device according to claim 47, wherein the sending unit is further configured to send the first NAS message to the terminal device.
49. The network device according to claim 48, wherein the sending unit is further configured to send a registration acceptance message to the terminal device, wherein the registration acceptance message includes at least one of the following:

    the first slice information is mapped to the second slice information;

    The allowed slice information is the second slice information.
50. The network device according to any one of claims 38 to 49, wherein the network device is an AMF.
51. The network device according to any one of claims 42 to 49, wherein the core network device is an SMF.
52. The network device according to any one of claims 38 to 51, wherein the first slice information and/or the second slice information is S-NSSAI.
53. A terminal device, comprising: a processor and a memory, the memory is used to store a computer program, the processor is used to call and run the computer program stored in the memory, so that the terminal device executes the execution of claims 1 to 12 The method of any of the above.
54. A network device, comprising: a processor and a memory, the memory is used to store a computer program, the processor is used to call and run the computer program stored in the memory, so that the network device executes as claimed in claims 13 to 26 The method of any of the above.
55. A chip, comprising: a processor for calling and running a computer program from a memory, so that a device on which the chip is installed executes the method according to any one of claims 1 to 12.
56. A chip, comprising: a processor for invoking and running a computer program from a memory, so that a device on which the chip is installed executes the method as claimed in any one of claims 13 to 26.
57. A computer-readable storage medium for storing a computer program which, when executed by a device, causes the device to perform the method of any one of claims 1 to 12.
58. A computer-readable storage medium for storing a computer program which, when executed by a device, causes the device to perform the method of any one of claims 13 to 26.
59. A computer program product comprising computer program instructions that cause a computer to perform the method of any one of claims 1 to 12.
60. A computer program product comprising computer program instructions that cause a computer to perform the method of any of claims 13 to 26.
61. A computer program that causes a computer to perform the method of any one of claims 1 to 12.
62. A computer program that causes a computer to perform the method of any one of claims 13 to 26.

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