WO2024027256A1

WO2024027256A1 - Communication method and apparatus

Info

Publication number: WO2024027256A1
Application number: PCT/CN2023/093134
Authority: WO
Inventors: 孙海洋; 韦庆
Original assignee: 华为技术有限公司
Priority date: 2022-08-03
Filing date: 2023-05-10
Publication date: 2024-02-08
Also published as: CN117560742A

Abstract

A communication method and apparatus, for maintaining the service continuity of a UE when S-NSSAI used by the UE needs to be updated. In the present application, the method comprises: a UE determines M pieces of S-NSSAI, M being an integer greater than or equal to 2; the UE sends a PDU session establishment request, wherein the PDU session establishment request comprises the M pieces of S-NSSAI, the PDU session establishment request is used for establishing a PDU session having attributes of N pieces of S-NSSAI, and the M pieces of S-NSSAI comprise the N pieces of S-NSSAI, N being an integer greater than or equal to 2; and the UE accesses a RAN, the RAN supporting any S-NSSAI in the N pieces of S-NSSAI.

Description

A communication method and device

Cross-references to related applications

This application claims priority to the Chinese patent application filed with the China Patent Office on August 3, 2022, with the application number 202210924329.1 and the application title "A communication method and device", the entire content of which is incorporated into this application by reference.

Technical field

The present application relates to the field of communication technology, and in particular, to a communication method and device.

Background technique

The fifth generation mobile communication (the 5th-generation, 5G) system introduces network slicing (NS) technology. Network slicing refers to a logical network customized according to different service requirements on physical or virtual network infrastructure. The terminal equipment (user equipment, UE) establishes a protocol data unit (PDU) session with the corresponding network slice according to the network requirements. The 3rd generation partnership project (3GPP) defines the user route selection policy (UE route selection policy, URSP). URSP is used to determine the PDU session selection parameters required by different applications (applications, APPs), such as Single network slice selection assistance information (S-NSSAI), data network name (DNN) and session service continuity (SSC) mode, etc.

The UE determines the PDU session selection parameters corresponding to the APP based on the URSP. When the UE has established a PDU session that satisfies the PDU session selection parameters corresponding to the APP, the UE routes the APP's data packet (packet) to the PDU session. If there is no PDU session that satisfies the PDU session selection parameters corresponding to the APP, The UE will initiate the establishment of a PDU session and establish a PDU session that meets the PDU session selection parameters corresponding to the APP.

When the S-NSSAI used by the UE needs to be updated, the UE needs to first release the PDU session in the original S-NSSAI, and then establish a PDU session in the new S-NSSAI. In this way, the service continuity of the UE cannot be maintained.

Contents of the invention

This application provides a communication method and device for maintaining the business continuity of the UE when the S-NSSAI used by the UE needs to be updated.

In a first aspect, the present application provides a communication method, which can be executed by a communication device. The communication device can be a terminal equipment (UE), or a module in the terminal equipment, such as a chip.

The communication method includes: the UE determines M S-NSSAIs, where M is an integer greater than or equal to 2. The UE sends a PDU session establishment request. The PDU session establishment request includes M S-NSSAIs. The PDU session establishment request is used to establish a PDU session with the attributes of N S-NSSAIs. The M S-NSSAIs include N S-NSSAIs. -NSSAI, N is an integer greater than or equal to 2. The UE accesses the radio access network (radio access network, RAN) equipment, and the RAN supports any S-NSSAI among N S-NSSAI.

In the above technical solution, when the S-NSSAI used by the UE needs to be updated, as long as the currently accessed RAN supports one or more S-NSSAI among N S-NSSAI, the RAN will not reject the PDU session, so the UE No need Releasing the PDU session helps maintain the business continuity of the UE.

In a possible implementation, M S-NSSAIs are included in the network slice selection assistance information (NSSAI) that is allowed to be used; or M S-NSSAIs are included in the NSSAI of the NSSAI mapping that is allowed to be used. middle. In this way, it is helpful for the UE to successfully request the establishment of the PDU session.

In a possible implementation, before the UE determines M S-NSSAI, it also includes: the UE receives URSP rules, and the URSP rules include multi-slice usage instructions; accordingly, the UE sends a PDU session establishment request, including: the UE sends a PDU session establishment request according to the multi-slice usage indication. Slice usage instructions, send PDU session establishment request. Optionally, the URSP rule includes a route selection descriptor (RSD), and the RSD includes M S-NSSAI and multi-slice usage instructions; or, the URSP rule includes K RSDs and multi-slice usage instructions, and K RSDs. includes M S-NSSAI, and K is a positive integer less than or equal to M. Optionally, the multi-slice usage instruction can additionally indicate which S-NSSAIs in RSDs to use, for example, by including route selection descriptor precedence (RSD precedence) in the multi-slice usage instruction.

In the above technical solution, a multi-slice usage indication is set in the URSP rule, and the UE requests to establish a PDU session with M S-NSSAI attributes according to the multi-slice usage indication in the URSP rule, so that the S-NSSAI used by the UE needs When updating, it helps to maintain the business continuity of the UE.

In a possible implementation, after the UE sends the PDU session establishment request, the method further includes: the UE receives first information, and the first information is used to indicate that the target SMF or target UPF used to establish the PDU session does not support M S-NSSAIs. The first part of S-NSSAI. Correspondingly, the UE determines, based on the first information, that the PDU session has attributes of N S-NSSAIs, and the N S-NSSAIs include other S-NSSAIs among the M S-NSSAIs except the first part of S-NSSAIs.

In the above technical solution, although the UE requests to establish a PDU session with attributes of M S-NSSAI, due to the limitations of the S-NSSAI supported by the target SMF or target UPF, the PDU session finally established supports part of the M S-NSSAI. (That is, N S-NSSAI). In this way, the UE determines that the UE can transmit data to the network side through the N S-NSSAI according to the M S-NSSAI and the first information.

In a second aspect, the present application provides a communication method, which can be executed by a communication device. The communication device can be an access network equipment (RAN), or a module in the RAN, such as a chip. The communication method includes: when the target RAN determines that the UE needs to be handed over from the source RAN to the target RAN, determine N S-NSSAI associated with the PDU session, where the PDU session is requested and established by the UE when accessing the source RAN, N It is an integer greater than or equal to 2; when the target RAN determines that the target RAN supports any S-NSSAI among N S-NSSAI, it accepts the PDU session.

In the above technical solution, when the UE is handed over from the source RAN to the target RAN, as long as the target RAN supports one or more S-NSSAIs among the N S-NSSAI associated with the PDU session, the target RAN will not reject the PDU session. , so the UE does not need to release the PDU session, which helps maintain the UE's business continuity.

In a third aspect, the present application provides a communication method, which can be executed by a communication device. The communication device can be a terminal equipment (UE), or a module in the terminal equipment, such as a chip.

The communication method includes: the UE receives a re-evaluation instruction, and the re-evaluation instruction is used to instruct the UE to re-evaluate the URSP rule corresponding to the first S-NSSAI; accordingly, the UE re-evaluates the URSP rule corresponding to the first S-NSSAI, obtaining Second S-NSSAI; the UE sends a PDU session request, which includes the second S-NSSAI. The PDU session request is used to establish a PDU session with the attributes of the second S-NSSAI, or to modify the established PDU. In the attributes of the session, the first S-NSSAI is the second S-NSSAI.

In the above technical solution, after receiving the re-evaluation instruction, the UE re-evaluates the URSP rule corresponding to the first S-NSSAI to obtain the second S-NSSAI. In this way, the UE requests in advance to establish the second S-NSSAI (that is, after the update). S-NSSAI), or request to modify the attributes of the established PDU session in which the first S-NSSAI is the second S-NSSAI, without the need to request the establishment of the second S-NSSAI after the PDU session is rejected by the RAN. The PDU session of S-NSSAI attributes helps maintain the business continuity of the UE.

In a possible implementation, the UE re-evaluates the URSP rule corresponding to the first S-NSSAI and obtains the second S-NSSAI. Specifically, the UE receives the candidate S-NSSAI, and the UE receives the candidate S-NSSAI according to the candidate S-NSSAI. The URSP rule corresponding to the first S-NSSAI is re-evaluated to obtain the second S-NSSAI, which is included in the candidate S-NSSAI.

In the above technical solution, the candidate S-NSSAI is the S-NSSAI pre-selected by the network side, and the UE selects the second S-NSSAI from the candidate S-NSSAI. The selected second S-NSSAI is more likely to be received by the network side. Improve the success rate of UE requesting to establish/modify PDU sessions.

In a possible implementation, the UE is also handed over from the source RAN to the target RAN, where the target RAN supports the PDU session with the second S-NSSAI attribute and does not support the PDU session with the first S-NSSAI attribute. Optionally, the target RAN does not support the first S-NSSAI, or the first S-NSSAI supported by the target RAN is in a congestion state. The source RAN supports PDU sessions with the first S-NSSAI attribute.

In the above technical solution, after the UE completes the establishment of a PDU session with the attributes of the second S-NSSAI, or modifies the first S-NSSAI in the attributes of the established PDU session to the second S-NSSAI, the UE is sent by the source RAN Switch to the target RAN. The target RAN supports the PDU session with the second S-NSSAI attribute. This helps to maintain the service continuity of the UE.

In the fourth aspect, this application provides a communication method, which can be executed by a communication device. The communication device can be an access and mobility management function network element (access mobile function, AMF), or a module in the AMF, such as a chip;

The communication device may also be a session management function network element (session management function, SMF), or a module in the SMF, such as a chip.

The communication method includes: after the first network element determines that there is a PDU session with the attribute of the second S-NSSAI, the first network element triggers a handover execution process for the UE to switch from the source RAN to the target RAN (or, RAN handover). Execution process); wherein, the second S-NSSAI is obtained by re-evaluating the URSP rule corresponding to the first S-NSSAI; the target RAN supports PDU sessions with the second S-NSSAI attribute, and does not support the first S-NSSAI Properties of the PDU session. In a possible implementation manner, the target RAN does not support the first S-NSSAI, or the first S-NSSAI supported by the target RAN is in a congestion state.

In the above technical solution, the target RAN supports the PDU session with the second S-NSSAI attribute. After the first network element determines that there is a PDU session with the second S-NSSAI attribute between the UE and the DN, the first network element triggers the UE The handover execution process from the source RAN to the target RAN, in this way, the PDU session with the attribute of the second S-NSSAI will be accepted by the target RAN, which helps to maintain the business continuity of the UE.

In a possible implementation, before the first network element determines that there is a PDU session with the attribute of the second S-NSSAI, the first network element also receives an unavailable indication, where the unavailable indication is used to indicate that the target RAN does not support PDU session with the first S-NSSAI attribute. In a possible implementation, during the establishment process of the PDU session, the first network element also sends a business continuity indication to the RAN. The business continuity indication is used to instruct the RAN to send an unavailability indication during the handover preparation process of the RAN. .

In the above technical solution, in the preparation phase for RAN handover, the RAN sends an unavailability indication to the first network element based on the business continuity indication, and waits for the handover execution instruction from the first network element, and the RAN receives the handover execution instruction from the first network element. The RAN handover execution process is executed only after the unit's handover execution instruction. In this way, when the UE accesses the target RAN, the target RAN rejects the PDU session with the first S-NSSAI attribute, causing the UE to release the PDU session.

In a possible implementation, before the first network element determines that there is a PDU session with the attribute of the second S-NSSAI, the first network element also sends a re-evaluation indication to the UE, and the re-evaluation indication is used to instruct to re-evaluate the first URSP rules corresponding to S-NSSAI. In a possible implementation, before the first network element determines that there is a PDU session with attributes of the second S-NSSAI, the first network element also receives a PDU session request, and the PDU session request includes the second S-NSSAI; A network element establishes a PDU session with the attributes of the second S-NSSAI, or modifies the first S-NSSAI in the attributes of the PDU session to the second S-NSSAI.

In the above technical solution, the first network element instructs the UE to re-evaluate the URSP rules corresponding to the first S-NSSAI to obtain the second S-NSSAI. In this way, the UE requests in advance to establish a network with the second S-NSSAI (that is, the updated S-NSSAI). NSSAI) attribute, or request to modify the attributes of the established PDU session in which the first S-NSSAI is the second S-NSSAI, without the need to request the establishment of the second S-NSSAI after the PDU session is rejected by the RAN. The PDU session of NSSAI attributes helps to maintain the business continuity of the UE.

In a possible implementation, before the first network element determines that there is a PDU session with attributes of the second S-NSSAI, the first network element also determines the candidate S-NSSAI, and the first network element sends the candidate S-NSSAI to the UE. ; Among them, the candidate S-NSSAI includes the second S-NSSAI.

In the above technical solution, the first network element indicates the candidate S-NSSAI to the UE. Correspondingly, the UE selects the second S-NSSAI from the candidate S-NSSAI. The selected second S-NSSAI is more likely to be received by the network side. , improve the success rate of UE requesting to establish/modify PDU sessions.

In a possible implementation, before the first network element determines that there is a PDU session with attributes of the second S-NSSAI, the first network element also sends a PDU session modification indication, and the PDU session modification indication is used to modify the established PDU. The first S-NSSAI in the session attributes is the second S-NSSAI.

In the above technical solution, the first network element can also determine the second S-NSSAI by itself and instruct the first S-NSSAI in the attributes of the PDU session to be modified to the second S-NSSAI, which has the attributes of the second S-NSSAI. The PDU session can be accepted by the target RAN, thus helping to maintain the UE's business continuity.

In a possible implementation, the first network element determines that a PDU session with the attribute of the second S-NSSAI exists when it determines that any of the following conditions are met: the first network element receives a completion indication from the UE, and the completion indication is After the PDU session establishment or modification is completed indicating that the attribute of the second S-NSSAI is present; the first network element determines that the duration of sending the re-evaluation indication to the UE reaches the first preset duration; the first network element is the AMF, and the AMF receives the PDU session modification indication: Send PDU session modification indication to the UE.

In a possible implementation, the first network element triggers the handover execution process of the RAN, including: the first network element sends a handover execution instruction to the target RAN, or the first network element sends a handover execution instruction to the source RAN; the handover execution Indicates the handover execution process used to trigger the RAN.

In the fifth aspect, embodiments of the present application provide a communication device, which has the function of implementing the UE in the above first aspect or any possible implementation manner of the first aspect. The device may be a UE or a UE in the UE. Chip included.

The device has the function of implementing the RAN in the above second aspect or any possible implementation manner of the second aspect. The device may be a RAN or a chip included in the RAN.

The communication device may also have the function of implementing the UE in the above third aspect or any possible implementation manner of the third aspect. The device may be a UE or a chip included in the UE.

The communication device may also have the function of implementing the first network element in the fourth aspect or any possible implementation manner of the fourth aspect. The device may be an AMF or a chip included in the AMF, or the device It can be SMF or a chip included in SMF.

The functions of the above communication device can be implemented by hardware, or can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules or units or means corresponding to the above functions.

In a possible implementation, the structure of the device includes a processing module and a transceiver module, wherein the processing module is configured to support the device to perform the corresponding UE in the above-mentioned first aspect or any implementation of the first aspect. Function, or perform the corresponding function of the RAN in the above second aspect or any implementation of the second aspect, or perform the corresponding function of the UE in the above third aspect or any implementation of the third aspect, or perform the above third aspect Corresponding functions of the first network element in any implementation of the fourth aspect or the fourth aspect. The transceiver module is used to support communication between the device and other communication devices. For example, when the device is a UE, the transceiver module is used for the UE to send a PDU session establishment request. The communication device may also include a storage module, which is coupled to the processing module and stores necessary program instructions and data for the device. As an example, the processing module can be a processor, the communication module can be a transceiver, and the storage module can be a memory. The memory can be integrated with the processor, or can be provided separately from the processor.

In another possible implementation, the structure of the device includes a processor and may also include a memory. The processor is coupled to the memory and can be used to execute computer program instructions stored in the memory, so that the device executes the above-mentioned first aspect or the method in any possible implementation of the first aspect, or executes the above-mentioned second aspect or the second aspect. The method in any possible implementation of the aspect, or the method in any possible implementation of the third aspect or the third aspect, or the method in any possible implementation of the fourth aspect or the fourth aspect. method in the implementation. Optionally, the device further includes a communication interface, and the processor is coupled to the communication interface. When the device is a UE, a RAN or a first network element, the communication interface may be a transceiver or an input/output interface; when the device is a chip included in the UE or a chip included in the RAN or a chip included in the first network element When the communication interface is used, the communication interface may be the input/output interface of the chip. Alternatively, the transceiver may be a transceiver circuit, and the input/output interface may be an input/output circuit.

In a sixth aspect, embodiments of the present application provide a chip system, including: a processor and a memory. The processor is coupled to the memory. The memory is used to store programs or instructions. When the programs or instructions are executed by the processor, the chip system implements The method in the above-mentioned first aspect or any possible implementation of the first aspect, or the method in realizing the above-mentioned second aspect or any possible implementation of the second aspect, or the method in realizing the above-mentioned third aspect or the third aspect A method in any possible implementation of the three aspects, or a method in any possible implementation of the fourth aspect or the fourth aspect.

Optionally, the chip system further includes an interface circuit for communicating code instructions to the processor.

Optionally, there may be one or more processors in the chip system, and the processor may be implemented by hardware or software. When implemented in hardware, the processor may be a logic circuit, an integrated circuit, or the like. When implemented in software, the processor may be a general-purpose processor implemented by reading software code stored in memory.

Optionally, there may be one or more memories in the chip system. The memory can be integrated with the processor or can be provided separately from the processor. For example, the memory may be a non-transient processor, such as a read-only memory ROM, which may be integrated with the processor on the same chip, or may be separately provided on different chips.

In a seventh aspect, embodiments of the present application provide a computer-readable storage medium on which a computer program or instructions are stored. When the computer program or instructions are executed, the computer is caused to execute the first aspect or any one of the first aspects. kind The method in the possible implementation manner, or perform the above second aspect or the method in any possible implementation manner of the second aspect, or perform the above third aspect or any possible implementation manner of the third aspect method, or a method for realizing the above fourth aspect or any possible implementation manner of the fourth aspect.

In an eighth aspect, embodiments of the present application provide a computer program product. When a computer reads and executes the computer program product, it causes the computer to execute the method in the above-mentioned first aspect or any possible implementation of the first aspect, or Perform the above second aspect or the method in any possible implementation of the second aspect, or perform the above third aspect or the method in any possible implementation of the third aspect, or implement the above fourth aspect or Methods in any possible implementation of the fourth aspect.

The technical effects that can be achieved by any one of the above-mentioned second to eighth aspects can be referred to the description of the beneficial effects in the above-mentioned first aspect, and will not be repeated here.

Description of the drawings

Figure 1 is a schematic diagram of a UE selecting a PDU session provided by this application;

Figure 2 is a schematic flow chart of a UE determining whether to establish a PDU session provided in this application;

Figures 3A to 3F are schematic architectural diagrams of a communication system provided by this application;

Figure 4 is a schematic diagram of a PDU session establishment process provided by this application;

Figure 5 is a schematic diagram of a RAN handover execution process provided by this application;

Figure 6 is a schematic flow chart of a communication method provided by this application;

Figure 7 is a schematic flow chart of another communication method provided by this application;

Figure 8 is a schematic structural diagram of a communication device provided by this application;

Figure 9 is a schematic structural diagram of a communication device provided by this application.

Detailed ways

In order to better explain the embodiments of the present application, the professional terms or technologies used in the embodiments of the present application are first explained.

1. 5G network scenario

5G supports three major scenarios: enhanced mobile broadband (eMBB), massive machine type communications (mMTC) and ultra-reliable and low latency communications (URLLC). The three scenarios include a variety of Differentiated applications.

eMBB: used to meet the transmission rate requirements of augmented reality (AR)/virtual reality (VR), high-definition video live broadcast and other applications.

mMTC: With the rapid development of smart cities recently, public facilities such as street lights, manhole covers, and water meters already have network connection capabilities and can be managed remotely. Based on the powerful connection capabilities of the 5G network, public equipment in various industries in the city are connected to the intelligent management platform. These public facilities work together through the 5G network and can be managed uniformly with only a small number of maintenance personnel, greatly improving the city's operational efficiency.

uRRLC: The most typical application in 5G scenarios is autonomous driving. The most common scenarios for autonomous driving include sudden braking, vehicle-to-vehicle, vehicle-to-person, vehicle-to-infrastructure and other multi-channel communications at the same time, which requires a large amount of data processing in an instant. and make decisions. Therefore, the network needs to have the capabilities of large bandwidth, low latency and high reliability at the same time.

2. Network slicing

1. Definition of network slicing

Network slicing uses slicing technology to virtualize multiple end-to-end networks based on a common hardware. Each network has different network functions and adapts to different types of service requirements. After purchasing physical resources, operators analyze the needs of various industries for network functions into requirements for network functions such as network bandwidth, number of connections, latency, and reliability, and then divide network slicing into three types based on application scenarios. They are eMBB type slices, mMTC type slices and URLLC type slices.

2. Choice of network slicing

(1) Single network slice selection assistance information (S-NSSAI), which can be used to identify a network slice. According to the operator's operation or deployment needs, one S-NSSAI can be associated with one or more network slicing instances, and one network slicing instance can be associated with one or more S-NSSAI.

Among them, S-NSSAI includes two parts: slice/servicetype (SST) and slice differentiator (SD). SST refers to the expected behavior of network slicing in terms of features and services. The standard value range of SST is 1, 2, and 3. The value 1 represents eMBB, the value 2 represents URLLC, and the value 3 represents massive internet of things (MIoT). SD is optional information used to supplement SST to distinguish multiple network slices of the same slice/service type. The two parts SST and SD are combined to represent the slice type and multiple slices of the same slice type. For example, the S-NSSAI values are 0x01000000, 0x02000000, and 0x03000000, which respectively represent eMBB type slices, uRLLC type slices, and MIoT type slices. The S-NSSAI values 0x01000001 and 0x01000002 represent eMBB type slices, serving user group 1 and user group 2 respectively.

(2) Network slice selection assistance information (NSSAI) is a collection of S-NSSNI. There are three types of NSSAI used in 5G networks as shown in Table 1.

Table 1

(3) Network slice selection policy (NSSP), the policy control function (PCF) uses NSSP as part of the UE route selection policy (URSP) rules and issues it to the UE through the AMF, NSSP is used for UE associated application identification (APP ID) and S-NSSAI.

(4) URSP, the UE selects an appropriate protocol data unit (PDU) session for the UE's uplink service flow according to the URSP. That is, some uplink services of the UE have certain requirements for the data network name (DNN), slicing, session service continuity mode (SSC mode) of the PDU session used.

The UE may trigger the establishment or modification of a PDU session during the execution of URSP. For example, the UE determines the current When there is no PDU session that meets the requirements, the UE will initiate a PDU session establishment process; when the UE determines that a PDU session that meets the requirements currently exists, it may directly use the existing PDU session. Combined with the example in Figure 1, when the UE is preparing to send the data of application A, it determines that application A's requirements for the PDU session used are DNN1, S-NSSAI-a, and SSC2. Then the UE can determine that application A transmits data through PDU session 2. .

When the UE executes URSP, specifically, every time the UE detects a new application, the UE evaluates whether the application matches the traffic descriptor in the URSP rule in the order of rule precedence. When there is a match, the UE selects the route selection descriptor (RSD) in the URSP rule in the order of route selection descriptor precedence (RSD precedence). When the RSD is invalid (valid, or effective) ), jump to the next RSD, otherwise select the RSD.

The RSD of a URSP rule shall be considered valid only if all the following conditions are met: Condition 1, if any S-NSSAI(s) are present, the S-NSSAI(s) are among the NSSAIs allowed in non-roaming situations ; In the case of roaming, S-NSSAI(s) are included in the mapping of allowed NSSAI to HPLMN S-NSSAI(s). Condition 2, if any DNN exists, and the DNN is a local area data network (LADN) DNN, the UE is in the availability area of this LADN. Condition 3, if a time window exists and the time matches the time indicated in the time window. Condition 4, if there is a location criterion and the UE's location matches what is indicated in the location criterion.

When there is a PDU session that meets the requirements (the attributes are the same as RSD), the UE will route the data packet of the application to the PDU session (when there are multiple PDU sessions, the UE will select one of them based on configuration, etc.). If there is no PDU session that meets the requirements, If the required PDU session is required, the UE will initiate the establishment of a PDU session and establish a PDU session with this attribute. In short, the UE will first detect whether there is a PDU session that meets the application requirements (DNN, network slicing, etc.). If there is, the current application will be mapped to the session. Otherwise, a PDU session that meets the application requirements will be established. as shown in picture 2.

Among them, the attributes of the PDU session include network slicing, DNN and SSC mode. 3GPP defines URSP to determine the correspondence between applications and network slicing, DNN and SSC modes.

Specifically, URSP includes one or more URSP rules. A URSP rule mainly includes two parts: traffic descriptor and RSD. Among them, the traffic descriptor includes the names or identifiers of multiple applications, etc., and the NSSAI corresponding to each application included in the RSD, that is, the NSSAI that is not included in the traffic descriptor and can be used by the application, etc. Among them, URSP can be seen in Table 2, URSP rules can be seen in Table 3, and RSD can be seen in Table 4.

Table 2

table 3

Table 4

Based on the above introduction to the professional terms and technologies involved in this application, the method in this application is explained as follows.

Embodiments of the present application provide a communication method that can be applied to 5G (fifth generation mobile communication system) systems, such as access networks using new radio access technology (New RAT); cloud wireless access Communication systems such as cloud radio access network (CRAN). Among them, the 5G system can be in a non-roaming scenario or a roaming scenario. The 5G system can be used in a service-oriented architecture or an interface-based architecture. There are no specific limitations here. It should be understood that the embodiments of the present application can also be applied to future communications (such as 6G or other networks).

The architecture of the communication system applicable to the communication method provided by the embodiments of the present application may include network opening function network elements, policy control function network elements, data management network elements, application function network elements, access and mobility management function network elements, session Manage functional network elements, UEs, access network equipment, user plane functional network elements and data networks.

The access and mobility management function network element and the UE can be connected through the N1 interface. The access and mobility management function network element can be connected to the access network equipment through the N2 interface. The access network equipment and the user plane function network can be connected through the N2 interface. The elements can be connected through the N3 interface, the session management function network element and the user plane function network element can be connected through the N4 interface, and the user plane function network element and the data network can be connected through the N6 interface. The interface name is just an example, and the embodiment of this application does not specifically limit it. Among them, the network elements in the communication system can be, but are not limited to, the network elements in the 5G architecture. The following uses the network elements in the 5G architecture as an example to describe the functions of each network element in the communication system:

UE, which can also be called user equipment (UE), mobile station (MS), mobile terminal (MT), etc., is a device that provides voice and/or data connectivity to users. . For example, the UE may include a handheld device, a vehicle-mounted device, etc. with a wireless connection function. Currently, UE can be: mobile phone (mobile phone), tablet computer, notebook computer, handheld computer, mobile internet device (mobile internet device, MID), wearable device, virtual reality (VR) device, augmented reality (augmented reality (AR) equipment, wireless terminals in industrial control (industrial control), wireless terminals in self-driving (self-driving), wireless terminals in remote medical surgery, and wireless terminals in smart grids Wireless terminals, wireless terminals in transportation safety, wireless terminals in smart cities Wire terminals, or wireless terminals in smart homes, etc.

The access network device may be an access network (AN), which provides wireless access services to UEs. The access network device is a device in the communication system that connects the UE to the wireless network. Access network equipment is a node in a wireless access network, which can also be called a base station or a radio access network (RAN) node (or device). Currently, some examples of access network equipment are: gNB, transmission reception point (TRP), evolved Node B (eNB), radio network controller (radio network controller, RNC), Node B (Node B, NB), base station controller (BSC), base transceiver station (BTS), home base station (for example, home evolved NodeB, or home Node B, HNB), baseband unit (base band unit (BBU), or wireless fidelity (wireless fidelity, Wifi) access point (access point, AP), etc.

The data network, such as data network (DN), can be the Internet, IP Multi-media Service (IMS) network, regional network (i.e. local network, such as mobile edge computing, MEC) network) etc. The data network includes an application server, which provides business services to the UE through data transmission with the UE.

The access and mobility management function network element can be used to manage the access control and mobility of UE. In practical applications, it includes the mobility management entity (mobility management) in the network framework in long term evolution (LTE). Entity, MME) mobility management function, and added the access management function, specifically responsible for UE registration, mobility management, tracking area update process, reachability detection, session management function network element selection, mobility status Conversion management and more. For example, in 5G, the access and mobility management function network element can be an AMF (access and mobility management function) network element. In future communications, such as 6G, the access and mobility management function network elements can still be AMF network elements, or have other names, which are not limited in this application. When the access and mobility management function network element is an AMF network element, AMF can provide Namf services.

The session management function network element can be used to be responsible for the session management of the UE (including the establishment, modification and release of the session), the selection and reselection of the user plane function network element, the Internet Protocol (IP) address allocation of the UE, and the quality of service. (quality of service, QoS) control, etc. For example, in 5G, the session management function network element can be an SMF (session management function) network element. In future communications, such as 6G, the session management function network element can still be an SMF network element, or have other names. This application No restrictions. When the session management function network element is an SMF network element, SMF can provide Nsmf services.

The policy control function network element can be used to be responsible for policy control decisions, provide functions such as business data flow and application detection, gating control, QoS and flow-based charging control, etc. For example, in 5G, the policy control function network element can be a PCF (policy control function) network element. In future communications, such as 6G, the policy control function network element can still be a PCF network element, or have other names. This application No restrictions. When the policy control function network element is a PCF network element, the PCF network element can provide Npcf services.

The main function of application function network elements is to interact with the 3rd generation partnership project (3GPP) core network to provide services to affect business flow routing, access network capability opening, policy control, etc. For example, in 5G, the application function network element can be an AF (application function) network element. In future communications, such as 6G, the application function network element can still be an AF network element, or have other names. This application does not limit it. . When the application function network element is an AF network element, the AF network element can provide Naf services.

The data management network element can be used to manage the UE's subscription data, UE-related registration information, etc. For example, in 5G, the data management network element can be a unified data management network element (UDM). For example, in 6G, the data management network element can still be a UDM network element, or have other names, which is not limited in this application. When the data management network element is a UDM network element, the UDM network element can provide Nudm services.

Network open function network elements can be used to enable 3GPP to securely provide network service capabilities to third-party AFs (for example, Service Capability Server (SCS), Application Server (AS), etc.). For example, in 5G, network exposure function network elements can be NEF (network exposure function). In future communications, such as 6G, network exposure function network elements can still be NEF network elements, or have other names. This application does not limited. When the network open function network element is an NEF, the NEF can provide Nnef services to other network function network elements.

In addition, the system architecture can also include other network elements, such as network slice selection function (NSSF), network function storage function (NF repository function, NRF), and authentication server function. AUSF) and so on, I will not list them one by one here.

Each of the above network elements can also be called a functional entity, which can be a network element implemented on dedicated hardware, a software instance running on dedicated hardware, or an instance of virtualized functions on an appropriate platform, for example, the above The virtualization platform can be a cloud platform.

FIG. 3A exemplarily shows a possible architectural diagram of a communication system based on service-based interfaces in a non-roaming scenario. Among them, Namf is the service-based interface displayed by AMF. Nsmf is a service-based interface exposed by SMF. Nnef is a service-based interface exposed by NEF. Npcf is the service-based interface exposed by PCF. Nudm is a service-based interface exposed by UDM. Naf is a service-based interface exposed by AF. Nnrf is a service-based interface exposed by NRF. Nausf is a service-based interface exposed by AUSF.

FIG. 3B illustrates a possible architectural diagram of a reference point-based communication system in a non-roaming scenario. Among them, N5 is the reference point between PCF and AF. N7 is the reference point between SMF and PCF. N8 is the reference point between UDM and AMF. N9 is the reference point between the 2 core UPFs. N10 is the reference point between UDM and SMF. N11 is the reference point between AMF and SMF. N12 is the reference point between AMF and AUSF. N14 is the reference point between the 2 AMFs. N15 is the reference point between PCF and AMF. N22 is the reference point between NSSF and AMF.

Figure 3C exemplarily shows a possible architectural diagram of a communication system based on service-based interfaces in a local breakout (LB) roaming scenario. Among them, the security edge protection proxy (SEPP) can be used for topology hiding, signaling filtering and policy formulation of the control plane interface within the public land mobile network (public land mobile network, PLMN), etc. V-SEPP is the roaming domain SEPP, H-SEPP is the local domain SEPP, and N32 is the reference point between V-SEPP and H-SEPP. Namf, Nsmf, Nnef, Npcf, Nudm, Naf, Nnrf and Nausf can be seen in Figure 3A and will not be repeated here.

Figure 3D exemplarily shows a possible architectural diagram of a reference point-based communication system in a local breakout roaming scenario. Among them, V-PCF is the roaming domain PCF, H-PCF is the local domain PCF, and N24 is the reference point between V-PCF and H-PCF. N5, N7, N8, N9, N10, N11, N12, N14, N15 and N22 can be seen in Figure 3B and will not be repeated here.

Figure 3E exemplarily shows a possible architectural diagram of a communication system based on service-based interfaces in a home routed (HR) roaming scenario. Among them, V-SEPP is the roaming domain SEPP, H-SEPP is the local domain SEPP, and N32 is the reference point between V-SEPP and H-SEPP. Namf, Nsmf, Nnef, Npcf, Nudm, Naf, Nnrf and Nausf can be seen in Figure 3A and will not be repeated here.

Figure 3F exemplarily shows a possible architectural diagram of a reference point-based communication system in a home routed roaming scenario. Among them, V-PCF is the roaming domain PCF, H-PCF is the local domain PCF, and N24 is V-PCF and H-PCF. reference points between. N5, N7, N8, N9, N10, N11, N12, N14, N15 and N22 can be seen in Figure 3B and will not be repeated here.

It should be understood that the embodiments of the present application are not limited to the communication systems shown in Figures 3A to 3F. The names of the network elements shown in Figures 3A to 3F are only used as examples here and are not applicable to the methods of this application. Limitation of network elements included in the communication system architecture. In addition, the devices in FIGS. 3A to 3F may be hardware, functionally divided software, or a combination of the above two.

It should be noted that the plurality involved in this application refers to two or more. "And/or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and/or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the related objects are in an "or" relationship. At the same time, it should be understood that although the terms first, second, third, etc. may be used to describe various messages, requests, and network elements in the embodiments of this application, these messages, requests, devices, and core network devices should not be limited to these. the term. These terms are only used to distinguish messages, requests, and network elements from each other.

This application provides a communication method. The UE requests to establish a PDU session, where the PDU session established by the request can support the N S-NSSAI, that is, the attributes of the PDU session include the N S-NSSAI, and N is greater than or equal to an integer of 2. In this way, when the RAN accessed by the UE supports any one of the N S-NSSAIs, it can accept the PDU session, which helps maintain the UE's business continuity.

The explanation is explained with reference to the schematic diagram of a PDU session establishment process exemplarily shown in FIG. 4 and the schematic diagram of a RAN handover (HO) execution process exemplarily shown in FIG. 5 .

In the PDU session establishment process shown in Figure 4:

Step 401: The UE determines M S-NSSAIs, where M is an integer greater than or equal to 2.

It should be noted in advance that before the UE determines M S-NSSAI, the UE obtains a URSP, where the URSP includes one or more URSP rules, where the URSP rules include M S-NSSAI and multi-slice usage instructions, and the multi-slice usage The indication is used to instruct the UE to request the establishment of a PDU session with M S-NSSAI attributes.

In possible mode 1, the URSP rule includes one or more RSDs, and the RSD includes one or more S-NSSAI. When the RSD includes multiple S-NSSAIs, the RSD also includes multi-slice usage instructions. For example, URSP rules include RSD1 and RSD2. RSD1 includes S-NSSAI 1, S-NSSAI 2, S-NSSAI 3, and multi-slice usage instructions; RSD2 includes S-NSSAI 4, S-NSSAI 5, and Instructions for using multiple slices.

In possible mode 2, the URSP rule includes one or more RSDs and multi-slice usage instructions, and the RSD includes one or more S-NSSAI. In the case where the URSP rule includes multiple RSDs, the multiple RSDs each contain different S-NSSAI. For example, URSP rules include RSD1, RSD2 and multi-slice usage instructions. RSD1 includes S-NSSAI 1, S-NSSAI 2, S-NSSAI 3, and RSD2 includes S-NSSAI 4 and S-NSSAI 5. In this implementation, the multi-slice usage instruction can additionally indicate which S-NSSAIs in which RSDs are used, for example, by including RSD precedence in the multi-slice usage instruction.

When the UE selects the URSP rule to be executed from the URSP, specifically, the UE is in a non-roaming scenario (that is, the UE is in HPLMN). If the UE determines that the S-NSSAI in the URSP rule is included in the allowed NSSAI, then This URSP rule can be used as a URSP rule to be executed; the UE is in a roaming scenario (that is, the UE is in a VPLMN). If the UE determines that the S-NSSAI in the URSP rule can be mapped to the allowed NSSAI, or in other words, the URSP rule The S-NSSAI is included in the mapping NSSAI of the allowed NSSAI, and the UE can use the URSP rule as the URSP rule to be executed. Among them, the NSSAI that is allowed to be used, or the mapping NSSAI of the NSSAI that is allowed to be used Specifically, the UE may obtain it from the AMF. The mapping NSSAI of the NSSAI allowed to be used, specifically, the NSSAI obtained when the NSSAI allowed to be used in the VPLMN is mapped to the HPLMN.

For example, if the UE is in a non-roaming scenario, the NSSAI allowed by HPLMN includes S-NSSAI A to S-NSSAI H. When the S-NSSAI in the URSP rule is S-NSSAI A to S-NSSAI E, the UE can Select this URSP rule as the URSP rule to be executed; the UE is in a roaming scenario, and the NSSAI allowed to be used by VPLMN are S-NSSAI a to S-NSSAI h, which are mapped to the S-NSSAI A to S-NSSAI H of HPLMN. When the URSP rule The S-NSSAI in are S-NSSAI A to S-NSSAI E, and the UE can select this URSP rule as the URSP rule to be executed.

When the UE selects a URSP rule as the URSP rule to be executed, the M S-NSSAI included in the selected URSP rule need to be included in the NSSAI that is allowed to be used, or in the NSSAI that is mapped to the NSSAI that is allowed to be used. In addition, it is also possible that the selected URSP rule contains multiple S-NSSAIs, and M S-NSSAIs among the multiple S-NSSAIs are included in the NSSAIs that are allowed to be used, or are included in the NSSAI mapping that is allowed to be used. in NSSAI. It can be understood that the selected URSP rule includes M S-NSSAI and multi-slice usage instructions. Further, the selected URSP rule includes an RSD, and the RSD includes M S-NSSAI and multi-slice usage instructions. Instructions; alternatively, the selected URSP rule includes K RSDs and multi-slice usage instructions, the K RSDs include M S-NSSAIs, and K is a positive integer less than or equal to M.

When executing the URSP rule, the UE determines whether the established PDU session meets the requirements.

Specifically, in the above possible method 1, if the UE determines that the attributes of a certain PDU session that have been established are the same as the RSD (that is, the multiple S-NSSAI included in the attributes of the PDU session are the same as the M S-NSSAI in the RSD) ), it is determined that the established PDU session meets the requirements; if the UE determines that one or more established PDU sessions do not have the same PDU session as the RSD, it is determined that the established PDU session does not meet the requirements.

In the above possible method 2, if the UE determines that the multiple S-NSSAI included in the attributes of a certain PDU session that has been established are the same as the M S-NSSAI included in the URSP rule, then the UE determines that the established PDU session The session meets the requirements; if the UE determines that there are no PDU sessions in one or more established PDU sessions in which the multiple S-NSSAI included in the attributes are the same as the M S-NSSAI included in the URSP rule, then the UE determines that the established PDU session The PDU session does not meet the requirements.

Step 402: The UE sends a PDU session establishment request to the AMF. The PDU session establishment request includes M S-NSSAI. Correspondingly, the AMF receives the PDU session establishment request from the UE.

Step 403: AMF selects a target SMF from multiple SMFs. There are two specific examples:

Example b-1: AMF determines which SMF among multiple SMFs supports the largest number of S-NSSAIs among the M S-NSSAIs, and then uses the determined SMF as the target SMF. Further, when the target SMF supports part of the M S-NSSAIs, the AMF sends the first information to the UE. Among the M S-NSSAIs included in the first information, the AMF does not support the S-NSSAIs that the target SMF does not support. , to indicate to the UE the S-NSSAI that the target SMF does not support.

Example b-2: AMF determines the SMF that supports the M S-NSSAI from multiple SMFs as the target SMF. In this case, if the AMF does not determine an SMF that supports the M S-NSSAIs from multiple SMFs, it may send a response rejecting PDU session establishment to the UE.

Step 404: The AMF sends a PDU session establishment request to the target SMF.

Among them, the PDU session establishment request includes m S-NSSAI, where the m S-NSSAI is M S-NSSAI; or, the m S-NSSAI is the M S-NSSAI excluding the S-NSSAI that is not supported by the target SMF. Other than NSSAI S-NSSAI (that is, the S-NSSAI supported by the target SMF among M S-NSSAI).

Correspondingly, the target SMF receives the PDU session establishment request.

Step 405: The target SMF selects a target UPF from multiple UPFs. There are two specific examples:

Example b-1: The target SMF determines which UPF among multiple UPFs supports the largest number of S-NSSAIs among the m S-NSSAIs, and then uses the determined UPF as the target UPF. Further, when the target UPF supports some S-NSSAIs among the m S-NSSAIs, the target SMF sends the first information to the UE. The first information includes the S-NSSAIs among the m S-NSSAIs that the target UPF does not support. NSSAI to indicate to the UE that the target UPF does not support S-NSSAI.

Example c-1: The target SMF determines the UPF that supports the m S-NSSAI from multiple UPFs as the target UPF. In this case, if the target SMF does not determine a UPF that supports the m S-NSSAIs from multiple UPFs, it may send a response rejecting PDU session establishment to the UE.

Combined with the above example b-1 and example c-1, here is an example of how to implement the establishment process of a PDU session initiated by the UE:

The PDU session establishment request initiated by the UE includes S-NSSAI 1 to S-NSSAI 5 (that is, the M S-NSSAI are S-NSSAI 1 to S-NSSAI 5). Correspondingly, AMF determines that the target SMF supports S-NSSAI 1 to S-NSSAI 4 but does not support S-NSSAI 5 based on S-NSSAI 1 to S-NSSAI 5. The AMF sends S-NSSAI 5 to the UE. In this way, the UE determines The attributes of the established PDU session do not include S-NSSAI 5. Further, the target SMF determines that the target UPF supports S-NSSAI 1 to S-NSSAI 3 based on S-NSSAI 1 to S-NSSAI 4. The target SMF sends S-NSSAI 4 to the UE through the AMF. In this way, the UE determines the value of the established PDU session. S-NSSAI 4 is not included in the attributes. That is, the attributes of the PDU session determined by the UE include S-NSSAI 1 to S-NSSAI 3.

The above only describes the implementation method of the UE requesting to establish a PDU session with M S-NSSAI attributes. For how the UE, SMF, AMF, UPF, etc. establish a PDU session, please refer to the description of the existing technology.

It can be understood that although the UE requests to establish a PDU session with attributes of M S-NSSAI, due to the limitations of the S-NSSAI supported by the target SMF or target UPF, the PDU session finally established supports part of the M S-NSSAI (i.e. N S-NSSAI), or in other words, N S-NSSAI are other S-NSSAI among M S-NSSAI except the first part of S-NSSAI that is not supported by the target SMF and/or target UPF. Of course, this application does not rule out that both the target SMF and the target UPF support the M S-NSSAI. In this case, the PDU session finally established by the PDU session establishment process supports the M S-NSSAI (ie, N S-NSSAI). That is, the PDU session establishment request is used to establish a PDU session having N attributes of S-NSSAI.

Step 406: The target SMF sends the attributes of the established PDU session to the RAN.

The attributes of the PDU session include the N S-NSSAI associated with the PDU session. In this way, when the RAN supports any one of the N S-NSSAIs, it can be considered that the RAN can provide communication services for the UE based on the PDU session. , or in other words, the RAN supports the PDU session, the RAN accepts (or does not reject, or does not disconnect) the PDU session, etc. The S-NSSAI provided to the RAN is the S-NSSAI with the serving PLMN value (i.e. HPLMN S-NSSAI in the case of non-roaming or home routing, or VPLMN S-NSSAI in the case of locally groomed roaming).

In the RAN handover (HO) execution flow shown in Figure 5:

Step 501: The UE is handed over from the source RAN to the target RAN. It is explained that during the movement process, the UE moves from the serving cell of the source RAN to the serving cell of the target RAN, and accordingly, the UE accesses the target RAN.

For example, the UE detects the strength of signals from multiple RANs during movement. Based on the signal strengths of the multiple RANs, it is determined that the signal strength of a certain RAN (ie, the target RAN) among the multiple RANs is higher than the current level of the UE. Access When the signal strength of the RAN (that is, the source RAN) is determined, handover from the source RAN to the target RAN is determined.

Step 502: The target RAN obtains N S-NSSAI associated with the PDU session.

The PDU session is the PDU session requested by the UE to be established in the relevant embodiment of Figure 4, and the attributes of the PDU session include N S-NSSAI associated with the PDU session.

Further, the target RAN also obtains the N S-NSSAI associated with the PDU from the source RAN. In the implementation of the target RAN obtaining the N S-NSSAI associated with the PDU, one way is that the target RAN requests the N S-NSSAI associated with the PDU from the source RAN, and then the source RAN sends the N S-NSSAI associated with the PDU to the target RAN. -NSSAI. Another way is that after the PDU session is established, the source RAN sends the N S-NSSAI associated with the PDU to one or more RANs surrounding the source RAN, where the one or more RANs include the target RAN.

Step 503: The target RAN determines that the target RAN supports any one of the N S-NSSAIs.

Optionally, the target RAN determines one or more S-NSSAIs supported by the target RAN, and determines that the target RAN supports the N S-NSSAIs based on the one or more S-NSSAIs supported by the target RAN and the N S-NSSAIs. One or more S-NSSAI in NSSAI (can be recorded as target S-NSSAI).

Further, the target RAN may determine that the target S-NSSAI supported by the target RAN is in a non-congested state. Or it can be understood that after the target RAN determines that the target RAN supports one or more S-NSSAIs among the N S-NSSAIs, the target RAN selects the target RAN from the one or more S-NSSAIs according to the congestion status of the one or more S-NSSAIs. Select the S-NSSAI in the non-congested state as the target S-NSSAI.

Step 504: The target RAN accepts the PDU session. In other words, the target RAN supports the PDU session, the target RAN does not reject/do not disconnect the PDU session, the PDU session can be successfully switched to the target RAN, etc.

In the above technical solution, when the movement of the UE causes the accessed RAN to change, as long as the currently accessed RAN (i.e., the target RAN) supports one or more S-NSSAIs among the N S-NSSAIs, the target RAN will not reject it. This PDU session, so the UE does not need to release the PDU session, which helps maintain the UE's business continuity.

In addition, if the target RAN determines that it does not support any one of the N S-NSSAIs, the target RAN rejects the PDU session. Optionally, the UE initiates a PDU session establishment request or modification request, so that the attributes of the PDU session include the S-NSSAI supported by the target RAN. For details, see the description in the relevant embodiments of Figure 6 or Figure 7 .

This application provides another possible communication method. In the preparation phase of RAN handover, if the first network element determines that the S-NSSAI (recorded as the first S-NSSAI) in the UE's PDU session is about to be unavailable, it instructs the UE to initiate PDU session establishment process/PDU session modification process, or the first network element actively initiates the PDU session modification process, so that there is a new PDU session with available S-NSSAI (recorded as the second S-NSSAI) between the UE and the DN, The first network element triggers the execution phase of RAN handover. Wherein, the first network element may be AMF or SMF.

In order to describe the embodiment of the present application more clearly, the following description is based on whether the first network element is an AMF or an SMF.

In case 1, the first network element is the AMF.

Furthermore, UE movement may also cause AMF handover, and the AMF may be the source AMF or the target AMF.

The flow chart of the communication method is shown in Figure 6.

Step 601: AMF sends a re-evaluation indication to the UE.

It can be understood that when the UE decides to switch from the source RAN to the target RAN, or in the handover preparation process of the RAN, the AMF determines that the first S-NSSAI in the UE's PDU session is about to be unavailable, and then sends a re-evaluation to the UE. instruct. The re-evaluation indication is used to instruct the UE to re-evaluate the URSP rule corresponding to the first S-NSSAI, Get a new available S-NSSAI, that is, the second S-NSSAI. Optionally, the first S-NSSAI is included in the re-evaluation instruction.

The following explanation explains how AMF determines that the first S-NSSAI in a PDU session is about to be unavailable:

Implementation method 1: The target RAN sends an unavailability indication to the AMF. Specifically, there are two examples:

Example 1-1, the target RAN obtains the PDU session context, and the target RAN determines that the target RAN does not support the first S-NSSAI according to the attributes of the PDU session in the PDU session context (that is, including the first S-NSSAI), or determines that the target RAN does not support the first S-NSSAI. The first S-NSSAI is supported but the current first S-NSSAI is in a congested state. The target RAN sends an unavailability indication to the AMF, where the unavailability indication is used to indicate that the target RAN does not support a PDU session having attributes of the first S-NSSAI. For example, the unavailability indication may be a 1-bit field. For example, when the value of this field is 1, it indicates that the target RAN does not support the PDU session having the attributes of the first S-NSSAI.

In this application, the target RAN does not support the PDU session with the attributes of the first S-NSSAI. Specifically, the target RAN does not support the first S-NSSAI, or the first S-NSSAI supported by the target RAN is in a congestion state.

Example 1-2: The target RAN sends an unavailability indication to the AMF. The unavailability indication is specifically the identification information of the target RAN, such as the tunnel information or RAN identification of the target RAN. For example, in Xn-based handover (Xn based HO) or N2-based handover (N2based HO), the target RAN sends the identification information of the target RAN to the AMF in the RAN handover preparation phase (HO preparation phase).

Exemplarily, the AMF determines one or more S-NSSAIs supported by the target RAN based on the identification information of the target RAN. When one or more S-NSSAIs supported by the target RAN does not include the first S-NSSAI, the AMF determines the target. The RAN does not support the first S-NSSAI. As another example, the AMF determines the congestion conditions corresponding to one or more S-NSSAIs supported by the target RAN and one or more S-NSSAIs supported by the target RAN based on the identification information of the target RAN. When one or more S-NSSAIs supported by the target RAN When multiple S-NSSAIs include the first S-NSSAI, but the first S-NSSAI is in a congested state in the target RAN, the AMF determines that the first S-NSSAI supported by the target RAN is in a congested state in the target RAN. In this way, the AMF determines that the target RAN does not support the PDU session having the attributes of the first S-NSSAI.

For example, when RAN establishes/maintains NG links (NG Setup, RAN configuration update), RAN will report one or more S-NSSAI supported by RAN. Correspondingly, the AMF determines one or more S-NSSAI supported by the target RAN based on the identification information of the target RAN.

Implementation Mode 2: The source RAN sends an unavailability indication to the AMF.

Example 2-1: The source RAN sends an unavailability indication to the AMF, where the unavailability indication is specifically the identification information of the target RAN obtained by the source RAN from the target RAN. The identification information of the target RAN is, for example, the tunnel information of the target RAN or the RAN identification. . For example, in N2-based handover, the source RAN decides to handover the UE to the target RAN. During the handover preparation phase of the RAN, the source RAN sends the identification information of the target RAN to the AMF (for example, through the HO required message to the AMF). According to the identification information of the target RAN, the AMF determines that the target RAN does not support the PDU session with the attribute of the first S-NSSAI. Please refer to the description in Example 2 of Implementation Mode 1.

Example 2-2: The source RAN sends an unavailability indication to the AMF. The unavailability indication is used to indicate that the target RAN does not support a PDU session with attributes of the first S-NSSAI. For example, the unavailability indication may be a 1-bit field. For example, when the value of this field is 1, it indicates that the target RAN does not support the PDU session having the attributes of the first S-NSSAI. Optionally, during XN link establishment/maintenance (Xn Setup, gNB configuration update), the source RAN obtains one or more S-NSSAI supported by the target RAN from the target RAN, and then determines that the target RAN does not support the first S-NSSAI. . Alternatively, the source RAN also obtains the congestion conditions corresponding to one or more S-NSSAIs supported by the target RAN from the target RAN, and then determines that the first S-NSSAI supported by the target RAN is in a congestion state. The specific determination method The formula is described in Example 1-1.

Optionally, the AMF also determines the candidate S-NSSAI and sends the determined candidate S-NSSAI to the UE. The candidate S-NSSAI refers to the S-NSSAI that can replace the first S-NSSAI, that is, the services associated with the PDU session of the first S-NSSAI can be delivered on the PDU session associated with the candidate S-NSSAI. The candidate S-NSSAI is the S-NSSAI with the serving PLMN value (i.e. HPLMN S-NSSAI in the case of non-roaming or home routing, or VPLMN S-NSSAI in the case of local grooming roaming). The candidate S-NSSAI can also be HPLMN S-NSSAI.

In the implementation manner in which the AMF determines the candidate S-NSSAI, the UDM may specifically determine the candidate S-NSSAI according to the UE's subscription information, (for example, both the candidate S-NSSAI and the first S-NSSAI belong to the S-NSSAI subscribed by the UE, Or the supported DNN is the same, etc.), and then the AMF obtains the candidate S-NSSAI from the UDM; or, the PCF determines the candidate S-NSSAI based on the UE's subscription information or URSP (for example, both the candidate S-NSSAI and the first S-NSSAI belong to The S-NSSAI signed by the UE, or the supported DNN is the same, or the supported applications are the same, etc.), and then the AMF obtains the candidate S-NSSAI from the PCF; or, the AMF obtains the UE's subscription information from the UDM or obtains the URSP from the PCF , determine the candidate S-NSSAI according to the UE's subscription information or URSP (for example, the candidate S-NSSAI and the first S-NSSAI both belong to the S-NSSAI subscribed by the UE, or support the same DNN, or support the same application, etc.).

Step 602: The UE re-evaluates the URSP rule corresponding to the first S-NSSAI to obtain the second S-NSSAI.

After receiving the re-evaluation indication, the UE determines that the first S-NSSAI is about to be unavailable, that is, it considers that the RSD containing the first S-NSSAI is no longer valid. Then, the UE re-evaluates the URSP rule corresponding to the first S-NSSAI. The second S-NSSAI is obtained, where the evaluation method can be found in the above descriptions of professional terms or technical explanations.

Optionally, the UE receives a broadcast message from the target RAN. The broadcast message includes one or more S-NSSAI-related information supported by the target RAN, such as a tracking area (track area, TA) and a supported network slice access group ( network slice as group (NSAG), the UE can determine one or more S-NSSAI related information supported by the target RAN based on the NSAG. The UE re-evaluates the URSP rules corresponding to the pair of first S-NSSAI according to one or more S-NSSAI supported by the target RAN, and obtains the second S-NSSAI. It can be understood that the second S-NSSAI is an S-NSSAI among one or more S-NSSAIs supported by the target RAN, that is, the target RAN supports the second S-NSSAI.

In addition, the UE can also sense that the first S-NSSAI is about to be unavailable, and then re-evaluate the URSP rule corresponding to the first S-NSSAI to obtain the second S-NSSAI. Exemplarily, the UE obtains the S-NSSAI supported by multiple TAs respectively (for example, obtained according to the above-mentioned NSAG). When the UE prepares to move from the first TA to the second TA, the UE obtains the S-NSSAI supported by the first TA and the second TA respectively. -NSSAI, determine the first S-NSSAI. Specifically, the attributes of the PDU session used by the UE in the first TA include the first S-NSSAI, and the UE determines that the second TA does not support the first S-NSSAI, so before moving to the second TA, the UE The URSP rule corresponding to the first S-NSSAI is re-evaluated to obtain the second S-NSSAI, in which the second TA supports the second S-NSSAI.

Optionally, the UE also receives the candidate S-NSSAI indicated by the AMF. The UE re-evaluates the URSP rule corresponding to the first S-NSSAI based on one or more S-NSSAI supported by the target RAN and the candidate S-NSSAI indicated by the AMF, and obtains the second S-NSSAI. It can be understood that the target RAN supports the second S-NSSAI, and the second S-NSSAI is the S-NSSAI among the candidate S-NSSAIs.

Step 603: The UE sends a PDU session request to the AMF, where the PDU session request includes the second S-NSSAI.

In one example, the PDU session request is a PDU session establishment request, and the PDU session establishment request is used to establish a PDU session with attributes of the second S-NSSAI.

Specifically, the UE sends a PDU session establishment request to the AMF, the AMF sends a PDU session establishment request to the SMF, and the SMF establishes a PDU session with attributes of the second S-NSSAI according to the second S-NSSAI in the PDU session establishment request. Or it can be understood that the RAN, AMF, and SMF respectively perform respective actions in the PDU session establishment process according to the second S-NSSAI included in the PDU session establishment request to establish a PDU session with attributes of the second S-NSSAI.

Optionally, after the PDU session establishment process ends, the UE also sends a completion indication to the AMF, where the completion indication is used to indicate that the PDU session establishment with the attributes of the second S-NSSAI is completed. Optionally, when the UE establishes the PDU session associated with the second S-NSSAI, it also carries the identifier (PDU Session ID) of the original PDU session associated with the first S-NSSAI, indicating that the original PDU session is replaced by the now established PDU session. .

In another example, the PDU session request is a PDU session modification request, and the PDU session modification request is used to modify the first S-NSSAI in the attributes of the PDU session to the second S-NSSAI.

Specifically, the UE sends a PDU session modification request to the AMF, the AMF sends a PDU session modification request to the SMF, and the SMF modifies the first S-NSSAI in the attributes of the PDU session to the second based on the second S-NSSAI in the PDU session modification request. S-NSSAI. Or it can be understood that RAN, AMF, and SMF respectively perform their respective actions in the PDU session modification process according to the second S-NSSAI included in the PDU session modification request to modify the first S-NSSAI in the attributes of the PDU session to the second S-NSSAI.

Optionally, after the PDU session modification process ends, the UE also sends a completion indication to the AMF, where the completion indication is used to indicate that the first S-NSSAI in the attributes of the PDU session is modified to the second S-NSSAI.

Step 604: The AMF determines that a PDU session with the attribute of the second S-NSSAI exists between the UE and the DN, and triggers the handover execution process of the RAN.

The AMF may determine the existence of a PDU session with attributes of the second S-NSSAI through one of the following methods.

Method 1: AMF receives the completion indication from the UE. The completion indication is sent by the UE to the AMF after the PDU session establishment process ends or after the PDU session modification process ends.

Method 2: The AMF determines that the time period for sending the re-evaluation indication to the UE reaches the first preset time period. For example, when sending the re-evaluation indication to the UE, the AMF starts a timer. When the timer reaches the first preset duration, the AMF determines that a PDU session with the attribute of the second S-NSSAI exists between the UE and the DN.

Method 3: The AMF determines that the PDU session with the attributes of the second S-NSSAI is successfully established, or determines that the first S-NSSAI in the attributes of the PDU session is modified to the second S-NSSAI. It can be understood that AMF is involved in the establishment process or modification process of the PDU session, and the AMF can sense whether the PDU session is established or modified.

After determining that a PDU session with the attribute of the second S-NSSAI exists between the UE and the DN, the AMF may send a handover execution instruction to the target RAN, or send a handover execution instruction to the source RAN, where the handover execution instruction is used to trigger the RAN switching execution process.

Optionally, during the PDU session establishment process, the AMF sends the S-NSSAI business continuity indication to the RAN. The business continuity indication is used to indicate: S-NSSAI congestion occurs due to UE movement or other reasons or the accessed RAN is no longer available. When the S-NSSAI is supported, the business continuity of the PDU session must still be guaranteed. In this way, in the preparation phase for RAN handover, the source RAN sends an unavailability indication to the AMF based on the business continuity indication, and waits for the handover execution indication from the AMF, and the source RAN performs the RAN handover only after receiving the handover execution indication from the AMF. execution process. In addition, in the preparation phase for RAN handover, the source RAN may also send an available indication to the AMF based on the business continuity indication. The available indication is used to instruct the target RAN to support a PDU session with the attributes of the first S-NSSAI. Correspondingly, the AMF triggers the execution process of RAN handover based on the available indication from the source RAN.

Optionally, AMF can obtain business continuity instructions from UDM. Or the SMF obtains the business continuity indication from the UDM, and then the SMF sends the business continuity indication to the AMF.

Optionally, the business continuity indication may be included in context (such as PDU session context or UE context). In this way, in the event that the AMF changes due to UE mobility or RAN handover, the target RAN or target AMF can obtain the business continuity indication from the context passed by the source RAN or source AMF.

The following examples provide various ways for the target RAN to obtain business continuity instructions:

Method (1), in Xn-based handover, the target RAN obtains the business continuity indication from the context (such as PDU session context or UE context) delivered by the source RAN.

Method (2), in N2-based handover, the target RAN obtains the context in the source RAN (such as PDU session context or UE context) via the core network, and then obtains the business continuity indication from the context; where, the target RAN obtains the context The path can include the target AMF and the source AMF in sequence.

Method (3): The target AMF obtains the business continuity indication from the UE context delivered by the source AMF, and sends the business continuity indication to the target RAN.

In method (4), the target AMF obtains the UE context from the source AMF, sends the UE context to the target RAN, and the target RAN obtains the business continuity indication from the UE context.

In one possible example, the business continuity indication is associated with a PDU session. Combined with the example in Table 5 below, PDU session 1 is associated with the business continuity indication, and PDU session 2 is not associated with the business continuity indication, then PDU session 1 needs to maintain the business continuity of the PDU session; PDU session 2 does not need to maintain the PDU Session business continuity.

table 5

In yet another possible example, the business continuity indication is associated with S-NSSAI. Combined with the example in Table 6 below, S-NSSAI 1 is associated with the business continuity indication, and S-NSSAI 2 is not associated with the business continuity indication, then the S-NSSAI 1 in the PDU session needs to maintain the S-NSSAI 1 Business continuity; S-NSSAI 2 in PDU session, there is no need to maintain business continuity of PDU session.

Table 6

In this implementation, the UE requests to establish a PDU session with the second S-NSSAI attribute, or requests to modify the first S-NSSAI in the PDU session to the second S-NSSAI. Furthermore, when the AMF determines that there is a PDU session with the second S-NSSAI attribute, - After the PDU session of the NSSAI attribute, trigger the RAN handover execution process. At this time, step 604 can also be understood as, for the PDU session associated with the business continuity indication, or the PDU session corresponding to the S-NSSAI associated with the business continuity indication, the AMF determines that an alternative PDU session is established for the above type of PDU session. Or when the above type of PDU session is modified, the RAN handover execution process is triggered. Optional, when all the above types of PDU sessions are When replacing or modifying, AMF triggers the RAN handover execution process.

In this way, when the UE accesses the target RAN, the target RAN accepts the PDU session with the attribute of the second S-NSSAI, which helps maintain the service continuity of the UE.

In case 2, the first network element is SMF.

The flow chart of the communication method is shown in Figure 7.

Step 701: The SMF sends a re-evaluation indication to the UE.

It can be understood that when the UE decides to switch from the source RAN to the target RAN, or in the handover preparation process of the RAN, the SMF determines that the first S-NSSAI in the UE's PDU session is about to be unavailable, and then sends it to the UE through the AMF. Reassess instructions. For the definition of the re-evaluation instruction, please refer to the description in step 601.

In one possible way, when the AMF determines that the first S-NSSAI in the PDU session is about to be unavailable, the AMF sends an unavailability indication to the SMF. In another possible way, the target RAN sends an unavailability indication to the SMF through the AMF, or the source RAN sends an unavailability indication to the SMF through the AMF. Based on the unavailability indication, the SMF determines that the first S-NSSAI in the PDU session is about to be unavailable. For this specific implementation, please refer to the description in step 601 above.

Optionally, SMF also determines candidate S-NSSAI. For the specific implementation method, please refer to the method in which the AMF determines the candidate S-NSSAI in step 601.

Step 702: The UE re-evaluates the URSP rule corresponding to the first S-NSSAI to obtain the second S-NSSAI. For specific implementation methods, please refer to the description in step 602 above.

Step 703: The UE sends a PDU session request to the AMF, where the PDU session request includes the second S-NSSAI. Correspondingly, the AMF sends the received PDU session request to the SMF, and the SMF establishes/modifies a PDU session with attributes of the second S-NSSAI according to the second S-NSSAI in the PDU session request. For specific implementation methods, please refer to the description in step 603 above.

Step 704: The SMF determines that a PDU session with the attribute of the second S-NSSAI exists between the UE and the DN, and triggers the RAN handover execution process.

The implementation method of SMF determining that there is a PDU session with the attribute of the second S-NSSAI between the UE and the DN can be understood by referring to the description in the above step 604. The above step "AMF" can be replaced with "SMF".

In addition, the AMF may also determine that there is a PDU session with the attribute of the second S-NSSAI between the UE and the DN, triggering the RAN handover execution process. For specific implementation methods, please refer to the description in step 604 above.

In addition, when the SMF determines that the first S-NSSAI in the UE's PDU session is about to be unavailable, the SMF can also initiate a PDU session modification process to modify the first S-NSSAI in the attributes of the PDU session to the second S -NSSAI. In this case, the SMF (and corresponding UPF) needs to support the alternative S-NSSAI. And in this case, after determining that the SMF initiates the PDU session modification process, the AMF can determine that a PDU session with the attributes of the second S-NSSAI exists between the UE and the DN, thereby triggering the RAN handover execution process.

It should also be added that during the PDU session establishment process, SMF can obtain business continuity instructions from UDM. Then, the SMF sends the business continuity indication to the RAN, or the SMF sends the business continuity indication to the RAN through the AMF. Normally, UE mobility or RAN handover does not cause SMF handover. Therefore, SMF can always retain context (such as PDU session context or UE context). Correspondingly, SMF can send context or services in the context to the target RAN. Continuity indication; Alternatively, the SMF may send the context, or the business continuity indication in the context, to the target RAN via the target AMF.

In this implementation, the UE requests to establish a PDU session with the second S-NSSAI attribute, or requests to modify the first S-NSSAI in the PDU session to the second S-NSSAI, or the SMF triggers the modification of the first S-NSSAI in the PDU session. -NSSAI is the second S-NSSAI. Further, after AMF/SMF determines that there is a PDU session with the second S-NSSAI attribute, the RAN handover execution process is triggered. In this way, when the UE accesses the target RAN, the target RAN accepts the PDU session with the attribute of the second S-NSSAI, which helps maintain the service continuity of the UE.

It should be added that in the relevant embodiments of Figure 6 or Figure 7, the first S-NSSAI that is not supported by the target RAN or the first S-NSSAI that is congested can be one or more. Correspondingly, UE, AMF, Network elements such as the SMF can perform the above method based on each first S-NSSAI to maintain business continuity of the PDU session in each first S-NSSAI.

It should be added that the relevant embodiments in Figure 6 or Figure 7 are not only applicable to the RAN switching process caused by UE movement, but also to other RAN switching processes, such as the active and backup RAN switching (RAN Initiated QoS Flow Mobility) process. It can be understood that as long as a handover between two RANs is involved, and the RAN after the handover does not support a PDU session with the attributes of the first S-NSSAI, the embodiments of the present application are applicable and realize the service continuity of the UE. sex.

Based on the above content and the same concept, FIG. 8 and FIG. 9 are schematic structural diagrams of possible communication devices provided by the present application. These communication devices can be used to implement the functions of the UE, RAN or the first network element (such as AMF or SMF) in the above method embodiments, and therefore can also achieve the beneficial effects of the above method embodiments.

In this application, the communication device may be a UE or RAN or AMF or SMF as shown in FIGS. 3A to 3F , or may be a module (such as a chip) applied in the UE or RAN or AMF or SMF.

As shown in FIG. 8 , the communication device 800 includes a processing module 801 and a transceiver module 802 .

When the communication device 800 is used to implement the functions of the UE in the method embodiment shown in Figure 4 or Figure 5 above:

The processing module 801 is used to determine M S-NSSAI, where M is an integer greater than or equal to 2;

The transceiver module 802 is used to send a PDU session establishment request. The PDU session establishment request includes M S-NSSAIs. The PDU session establishment request is used to establish a PDU session with attributes of N S-NSSAIs, wherein the M S-NSSAIs Including N S-NSSAI, N is an integer greater than or equal to 2;

The processing module 801 is also used to access the communication device to the RAN. The RAN supports any S-NSSAI among N S-NSSAI.

In a possible implementation, M S-NSSAIs are included in the NSSAI that is allowed to be used; or M S-NSSAIs are included in the NSSAI mapped by the NSSAI that is allowed to be used.

In a possible implementation, the transceiver module 802 is also used to receive URSP rules before the processing module 801 determines M S-NSSAIs. The URSP rules include multi-slice usage instructions; when the transceiver module 802 sends a PDU session establishment request, , specifically used to send a PDU session establishment request according to the multi-slice usage instructions.

In a possible implementation, the URSP rules include RSDs, and the RSDs include M S-NSSAIs and multi-slice usage instructions; or the URSP rules include K RSDs and multi-slice usage instructions, and the K RSDs include M S-NSSAIs. NSSAI, K is a positive integer less than or equal to M.

In a possible implementation, after sending the PDU session establishment request, the transceiver module 802 is also configured to receive first information. The first information is used to indicate that the target SMF or target UPF used to establish the PDU session does not support M S - the first part of S-NSSAI in the NSSAI; the processing module 801 is also configured to determine, based on the first information, that the PDU session has the attributes of N S-NSSAI, and the N S-NSSAI includes M S-NSSAI except the first part of S- S-NSSAI other than NSSAI.

When the communication device 800 is used to implement the functions of the target RAN in the above method embodiment shown in Figure 4 or Figure 5:

The processing module 801 is configured to determine N S-NSSAI associated with the PDU session when it is determined that the UE needs to be handed over from the source RAN to the target RAN, where the PDU session is requested and established by the UE when accessing the source RAN, N is an integer greater than or equal to 2; and when it is determined that the target RAN supports any S-NSSAI among N S-NSSAI, accept the PDU session. The transceiver module 802 is configured to receive N S-NSSAI associated with the PDU session from the source RAN.

When the communication device 800 is used to implement the functions of the UE in the method embodiment shown in Figure 6 or Figure 7 above:

The transceiver module 802 is used to receive a re-evaluation instruction, and the re-evaluation instruction is used to instruct the UE to re-evaluate the URSP rule corresponding to the first S-NSSAI; the processing module 801 is used to re-evaluate the URSP rule corresponding to the first S-NSSAI. Evaluate and obtain the second S-NSSAI; the transceiver module 802 is also used to send a PDU session request, the PDU session request includes the second S-NSSAI, and the PDU session request is used to establish a PDU session with attributes of the second S-NSSAI, Or, the first S-NSSAI is used to modify the attributes of the established PDU session to the second S-NSSAI.

In a possible implementation, the transceiver module 802 is also used to receive candidate S-NSSAI; the processing module 801 is specifically used to re-evaluate the URSP rules corresponding to the first S-NSSAI and obtain the second S-NSSAI. According to the candidate S-NSSAI, the URSP rule corresponding to the first S-NSSAI is re-evaluated to obtain the second S-NSSAI. The second S-NSSAI is included in the candidate S-NSSAI.

In a possible implementation, the processing module 801 is also used to switch the communication device from the source RAN to the target RAN. The target RAN supports the PDU session with the second S-NSSAI attribute and does not support the first S-NSSAI attribute. PDU session. In a possible implementation manner, the target RAN does not support the first S-NSSAI, or the first S-NSSAI supported by the target RAN is in a congestion state.

When the communication device 800 is used to implement the function of the first network element in the above method embodiment shown in Figure 6 or Figure 7:

The processing module 801 is used to determine that there is a PDU session with the attribute of the second S-NSSAI; and trigger the handover execution process of the UE from the source RAN to the target RAN; wherein the second S-NSSAI is a response to the first S-NSSAI. The corresponding URSP rule is re-evaluated; the target RAN supports PDU sessions with the second S-NSSAI attribute, and does not support PDU sessions with the first S-NSSAI attribute. In a possible implementation manner, the target RAN does not support the first S-NSSAI, or the first S-NSSAI supported by the target RAN is in a congestion state.

In a possible implementation, before determining that there is a PDU session with the attribute of the second S-NSSAI, the processing module 801 is also used to control the transceiver module 802 during the handover preparation process of the UE switching from the source RAN to the target RAN. Receive an unavailable indication, wherein the unavailable indication is used to indicate that the target RAN does not support the PDU session with the first S-NSSAI attribute.

In a possible implementation, before determining that a PDU session with the attribute of the second S-NSSAI exists, the processing module 801 is also configured to control the transceiver module 802 to send a business continuity indication to the RAN during the establishment process of the PDU session. , the business continuity indication is used to instruct the RAN to send an unavailability indication during the handover preparation process.

In a possible implementation, before determining that there is a PDU session with the attribute of the second S-NSSAI, the processing module 801 is also used to control the transceiver module 802 to send a re-evaluation indication to the UE. The re-evaluation indication is used to indicate re-evaluation. The URSP rule corresponding to the first S-NSSAI.

In a possible implementation, the processing module 801 is also used to determine candidate S-NSSAI before determining that there is a PDU session with attributes of the second S-NSSAI; and, control the transceiver module 802 to send the candidate S-NSSAI to the UE. ; Among them, the candidate S-NSSAI includes the second S-NSSAI.

In a possible implementation, before determining that a PDU session with the attribute of the second S-NSSAI exists, the processing module 801 is also used to control the transceiver module 802 to receive a PDU session request, where the PDU session request includes the second S-NSSAI. ; Establish a PDU session with the attributes of the second S-NSSAI, or modify the first S-NSSAI in the attributes of the established PDU session to the second S-NSSAI.

In a possible implementation, before determining that there is a PDU session with the attribute of the second S-NSSAI, the processing module 801 is also used to control the transceiver module 802 to send a PDU session modification indication. The PDU session modification indication is used to modify the established The first S-NSSAI in the attributes of the PDU session is the second S-NSSAI.

In a possible implementation, the processing module 801 determines that there is a PDU session with the attribute of the second S-NSSAI when determining that any of the following conditions are met: the transceiver module 802 receives a completion indication from the UE, and the completion indication is used to indicate The establishment or modification of the PDU session with the attributes of the second S-NSSAI is completed; it is determined that the duration of the re-evaluation indication sent by the transceiver module 802 to the UE reaches the first preset duration; the communication device is an AMF, and the transceiver module 802 receives the PDU session modification from the SMF Instruction: Send PDU session modification indication to the UE.

In a possible implementation, when the processing module 801 triggers the handover execution process of the RAN, it is specifically used to: control the transceiver module 802 to send a handover execution instruction to the target RAN, or to send a handover execution instruction to the source RAN; the handover execution instruction is To trigger the switching execution process.

Figure 9 shows a device 900 provided by an embodiment of the present application. The device shown in Figure 9 can be a hardware circuit implementation of the device shown in Figure 8. The device may be adapted to the flow chart shown above to perform the functions of the UE, RAN, or first network element in the above method embodiment. For ease of explanation, Figure 9 shows only the main components of the device.

The device 900 shown in Figure 9 includes a communication interface 910, a processor 920 and a memory 930, where the memory 930 is used to store program instructions and/or data. The processor 920 may cooperate with the memory 930. Processor 920 may execute program instructions stored in memory 930 . When the instructions or programs stored in the memory 930 are executed, the processor 920 is used to perform the operations performed by the processing module 801 in the above embodiment, and the communication interface 910 is used to perform the operations performed by the transceiver module 802 in the above embodiment.

Memory 930 and processor 920 are coupled. The coupling in the embodiment of this application is an indirect coupling or communication connection between devices, units or modules, which may be in electrical, mechanical or other forms, and is used for information interaction between devices, units or modules. At least one of the memories 930 may be included in the processor 920 .

In this embodiment of the present application, the communication interface may be a transceiver, a circuit, a bus, a module, or other types of communication interfaces. In this embodiment of the present application, when the communication interface is a transceiver, the transceiver may include an independent receiver or an independent transmitter; it may also be a transceiver with integrated transceiver functions or a communication interface.

Apparatus 900 may also include communication lines 940. Among them, the communication interface 910, the processor 920 and the memory 930 can be connected to each other through a communication line 940; the communication line 940 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (extended industry standard architecture) , referred to as EISA) bus, etc. The communication line 940 can be divided into an address bus, a data bus, a control bus, etc. For ease of presentation, only one thick line is used in Figure 9, but it does not mean that there is only one bus or one type of bus.

Based on the above content and the same concept, embodiments of the present application provide a computer-readable storage medium on which a computer program or instructions are stored. When the computer program or instructions are executed, the computer is caused to execute the method in the above method embodiment.

Based on the above content and the same concept, embodiments of the present application provide a computer program product. When a computer reads and executes the computer program product, it causes the computer to execute the method in the above method embodiment.

It can be understood that the various numerical numbers involved in the embodiments of the present application are only for convenience of description and are not used to limit the scope of the embodiments of the present application. The size of the serial numbers of the above processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic.

Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the protection scope of the present application. In this way, if these modifications and variations of the present application fall within the scope of the claims of the present application and equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

A communication method, characterized by including:

The terminal equipment UE determines M pieces of single network slice selection assistance information S-NSSAI, where M is an integer greater than or equal to 2;

The UE sends a protocol data unit PDU session establishment request, the PDU session establishment request includes the M S-NSSAI, and the PDU session establishment request is used to establish a PDU session with attributes of N S-NSSAI, where , the M S-NSSAI includes the N S-NSSAI, and the N is an integer greater than or equal to 2;

The UE accesses a radio access network device RAN, and the RAN supports any one of the N S-NSSAIs.
The method of claim 1, wherein the M S-NSSAIs are included in the network slice selection auxiliary information NSSAI that is allowed to be used; or

The M S-NSSAIs are included in the NSSAIs of the allowed NSSAI mapping.
The method according to claim 1 or 2, characterized in that,

Before the UE determines the M S-NSSAI, the method further includes: the UE receives a user routing policy URSP rule, where the URSP rule includes a multi-slice usage indication;

The UE sends a PDU session establishment request, including: the UE sends the PDU session establishment request according to the multi-slice usage indication.
The method of claim 3, wherein the URSP rule includes a path selection descriptor RSD, and the RSD includes the M S-NSSAI and the multi-slice usage indication; or,

The URSP rule includes K RSDs and the multi-slice usage instructions, the K RSDs include the M S-NSSAIs, and the K is a positive integer less than or equal to the M.
The method according to any one of claims 1 to 4, characterized in that after the UE sends a PDU session establishment request, it further includes:

The UE receives first information, the first information is used to indicate that the target SMF or target UPF used to establish the PDU session does not support the first part of the M S-NSSAI;

The UE determines that the PDU session has attributes of the N S-NSSAI according to the first information, and the N S-NSSAI includes the M S-NSSAI except the first part of the S-NSSAI. Other than S-NSSAI.
A communication method, characterized by including:

The terminal equipment UE receives a re-evaluation indication, which is used to instruct the UE to re-evaluate the user routing policy URSP rule corresponding to the first single network slice selection assistance information S-NSSAI;

The UE re-evaluates the URSP rule corresponding to the first S-NSSAI to obtain the second S-NSSAI;

The UE sends a protocol data unit PDU session request, the PDU session request includes the second S-NSSAI, and the PDU session request is used to establish a PDU session with attributes of the second S-NSSAI, or, The first S-NSSAI used to modify the attributes of the established PDU session is the second S-NSSAI.
The method of claim 6, wherein the UE re-evaluates the URSP rule corresponding to the first S-NSSAI to obtain the second S-NSSAI, including:

The UE receives the candidate S-NSSAI;

The UE re-evaluates the URSP rule corresponding to the first S-NSSAI based on the candidate S-NSSAI. It is estimated that the second S-NSSAI is obtained, and the second S-NSSAI is included in the candidate S-NSSAI.
The method of claim 6 or 7, further comprising:

The UE is handed over from the source radio access network device RAN to the target RAN, and the target RAN supports the PDU session with the second S-NSSAI attribute and does not support the PDU session with the first S-NSSAI attribute.
The method of claim 8, wherein the target RAN does not support the first S-NSSAI, or the first S-NSSAI supported by the target RAN is in a congestion state.
A communication method, characterized by including:

The first network element determines that there is a protocol data unit PDU session having attributes of the second single network slice selection assistance information S-NSSAI;

The first network element triggers a handover execution process for the terminal equipment UE to switch from the source radio access network equipment RAN to the target RAN;

Wherein, the second S-NSSAI is obtained by re-evaluating the user routing policy URSP rule corresponding to the first S-NSSAI; the target RAN supports PDU sessions with the second S-NSSAI attribute, and does not support A PDU session having the first S-NSSAI attribute.
The method of claim 10, wherein the target RAN does not support the first S-NSSAI, or the first S-NSSAI supported by the target RAN is in a congestion state.
The method according to claim 10 or 11, characterized in that before the first network element determines that there is a PDU session with attributes of the second S-NSSAI, it further includes:

In the handover preparation process for the UE to switch from the source RAN to the target RAN, the first network element receives an unavailability indication, wherein the unavailability indication is used to indicate that the target RAN does not support the first S -NSSAI attribute PDU session.
The method of claim 12, wherein before the first network element determines that there is a PDU session with attributes of the second S-NSSAI, it further includes:

In the establishment process of the PDU session, the first network element sends a business continuity indication to the RAN, and the business continuity indication is used to instruct the RAN to send the unavailability indication in the handover preparation process.
The method according to any one of claims 10 to 13, characterized in that before the first network element determines that there is a PDU session with attributes of the second S-NSSAI, it further includes:

The first network element sends a re-evaluation indication to the UE, where the re-evaluation indication is used to instruct to re-evaluate the URSP rule corresponding to the first S-NSSAI.
The method according to any one of claims 10 to 14, characterized in that before the first network element determines that there is a PDU session with attributes of the second S-NSSAI, it further includes:

The first network element determines the candidate S-NSSAI;

The first network element sends the candidate S-NSSAI to the UE;

Wherein, the candidate S-NSSAI includes the second S-NSSAI.
The method according to any one of claims 10 to 15, characterized in that before the first network element determines that there is a PDU session with attributes of the second S-NSSAI, it further includes:

The first network element receives a PDU session request, where the PDU session request includes the second S-NSSAI;

The first network element establishes a PDU session with attributes of the second S-NSSAI, or modifies the first S-NSSAI in the attributes of the established PDU session to the second S-NSSAI.
The method according to any one of claims 10 to 13, characterized in that before the first network element determines that there is a PDU session with attributes of the second S-NSSAI, it further includes:

The first network element sends a PDU session modification indication, and the PDU session modification indication is used to modify the first S-NSSAI in the attributes of the established PDU session to the second S-NSSAI.
The method according to any one of claims 10-16, characterized in that, when the first network element determines that any one of the following conditions is met, it determines that there is a PDU session with attributes of the second S-NSSAI:

The first network element receives a completion indication from the UE, where the completion indication is used to indicate that the PDU session establishment or modification with the attributes of the second S-NSSAI is completed;

The first network element determines that the time period for sending the re-evaluation indication to the UE reaches a first preset time period;

The first network element is the access and mobility management function network element AMF. The AMF receives the PDU session modification indication from the session management function network element SMF and sends the PDU session modification indication to the UE.
The method according to any one of claims 10 to 18, characterized in that the first network element triggers a handover execution process of the RAN, including:

The first network element sends a handover execution instruction to the target RAN, or the first network element sends a handover execution instruction to the source RAN; the handover execution instruction is used to trigger the handover execution process.
A communication device, characterized in that it includes a module for performing the method according to any one of claims 1 to 5, or a module for the method according to any one of claims 6 to 9, or one of the methods described in claims 10 to 19. module of any of the methods described.
A communication device, characterized in that it includes a processor and a communication interface. The communication interface is used to receive signals from other communication devices other than the communication device and transmit them to the processor or transfer signals from the processor. The signal is sent to other communication devices other than the communication device, and the processor is used to implement the method according to any one of claims 1 to 5, or 6 to 9 through logical circuits or execution of code instructions. The method described in any one of the above, or the method described in any one of 10 to 19.
A computer-readable storage medium, characterized in that computer programs or instructions are stored in the computer-readable storage medium. When the computer programs or instructions are executed by a communication device, any one of claims 1 to 5 is realized. The method described in one item, or the method described in any one of 6 to 9, or the method described in any one of 10 to 19.