Communication method and apparatus

Abstract

A communication method and apparatus. In the method, a first network device determines that a first network slice is unavailable, and sends to a terminal device a mapping relationship between the first network slice and a second network slice and first NSAG information, wherein the first network slice is an allowed network slice of the terminal device, the second network slice is a network slice that replaces the first network slice, and the first NSAG information does not include NSAG information associated with the first network slice. Since the first NSAG information does not include NSAG information associated with the first network slice, when executing cell reselection, the terminal device does not reselect a cell that only supports the first network slice, thereby improving the success rate of the terminal device in initiating a slicing service request after executing cell reselection based on network slicing, or improving the accuracy of an access network device in quickly identifying a service of the terminal device when the terminal device executes random access on the basis of network slicing.

Description

Communication method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on October 31, 2023, with application number 202311436006.9 and application name "A Communication Method and Device", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The embodiments of the present application relate to the field of wireless communications, and in particular to a communication method and apparatus. Background Art

[0004] With the development of mobile communication technology, various new services and application scenarios are constantly emerging. These services have significantly different requirements for network functions, connectivity performance, and security. If a single network is used to carry these services, it will be difficult to simultaneously meet the requirements of high bandwidth, low latency, and high reliability. Establishing a separate network for each service will also incur huge costs. This requires communication systems to be flexible and scalable while being able to meet diverse service requirements. Therefore, 5G communication systems provide users with customized network services through end-to-end network slicing. By flexibly allocating network resources and on-demand networking, 5G communication systems can create multiple, isolated network slices with different characteristics on the same physical infrastructure to provide targeted services to users.

[0005] However, when the network slice deployed in the core network (CN) is congested or unavailable, how to improve the success rate of network slice service requests for idle or inactive user equipment (UE) is a technical problem that needs to be solved.

[0006] Summary of the Invention

[0007] The present application provides a communication method and a communication device for enabling a terminal device in an idle or inactive state to perform cell reselection and / or random access based on network slice access layer group (network slice AS Group, NSAG) information when a network slice deployed in a core network is congested or unavailable.

[0008] In a first aspect, an embodiment of the present application provides a communication method, applied to a first network device, the method comprising: determining that a first network slice is unavailable, and the first network slice belongs to a network slice allowed by a terminal device; sending a mapping relationship between the first network slice and a second network slice and first NSAG information to the terminal device, wherein the second network slice is a network slice that replaces the first network slice to provide services to the terminal device, and the first NSAG information does not include NSAG information associated with the first network slice.

[0009] In the above method, after determining that the first network slice allowed by the terminal device is unavailable, the first network device sends the mapping relationship between the first network slice and the second network slice and the first NSAG information to the terminal device. Since the first NSAG information does not include the NSAG information associated with the first network slice, the terminal device will not reselect to a cell that only supports the first network slice when performing cell reselection, which helps the terminal device to perform network slice-based cell reselection based on the NSAG associated with the second network slice, and helps to improve the success rate of the terminal device initiating a slice service request after performing network slice-based cell reselection; or, helps the terminal device to perform network slice-based random access based on the NSAG associated with the second network slice, and helps to improve the accuracy of the access network device in quickly identifying the terminal device service when the terminal device performs random access based on the network slice.

[0010] Since cell reselection and / or random access based on network slicing needs to be performed according to the NSAG information associated with the network slice, in an embodiment of the present application, performing cell reselection and / or random access based on NSAG information has the same meaning as performing cell reselection and / or random access based on network slicing, and the operations performed by the terminal device are consistent.

[0011] In one possible implementation, the method further includes: when the first network slice becomes available again, sending second NSAG information to the terminal device, where the second NSAG information includes NSAG information associated with the first network slice. When the first network slice is restored, the first network device may further send the NSAG information associated with the first network slice to the terminal device, thereby enabling the terminal device to initiate a service request based on the first network slice, thereby facilitating load balancing.

[0012] In one possible implementation, determining that the first network slice is unavailable includes: receiving a mapping relationship between the first network slice and the second network slice, where the mapping relationship is sent when determining that the first network slice is unavailable. The first network device may not directly determine whether the network slice is available, nor directly determine a second network slice to replace the first network slice, but may determine that the first network slice is unavailable based on the received mapping relationship between the first network slice and the second network slice.

[0013] In one possible implementation, the method further includes: obtaining network slices and third NSAG information supported by the access network device. The first network device may obtain the network slices and third NSAG information supported by the access network device, thereby facilitating the first network device to provide NSAG information to the terminal device during subsequent communication based on the network slices and third NSAG information supported by the access network device.

[0014] In one possible implementation, the third NSAG information does not include the NSAG information associated with the second network slice; after obtaining the network slices and third NSAG information supported by the access network device, the method further includes: sending first indication information, wherein the first indication information is used to indicate that the NSAG information associated with the second network slice is configured; and obtaining the NSAG information associated with the second network slice. When the first network device determines that the NSAG information associated with the second network slice has not been obtained, it may send the first indication information to indicate that the NSAG information associated with the second network slice is configured, and obtain the NSAG information associated with the second network slice, thereby facilitating the sending of the NSAG information associated with the second network slice to the terminal device, so that the terminal device can perform cell reselection and / or random access based on the NSAG information associated with the second network slice.

[0015] In one possible implementation, before sending the first indication information, the method further includes: determining an access network device that supports the second network slice. The first network device may send the first indication information to the access network device that supports the second network slice, so that the access network device that supports the second network slice configures associated NSAG information for the second network slice. Alternatively, the first network device may not determine which access network devices support the second network slice, but instead send the first indication information to multiple access network devices, and the access network devices may determine whether they can configure associated NSAG information for the second network slice.

[0016] In one possible implementation, the first NSAG information includes NSAG information associated with the second network slice. The first network device sends the NSAG information associated with the second network slice to the terminal device, so that the terminal device can perform cell reselection and / or random access based on the NSAG information associated with the second network slice, which helps to improve the success rate of the terminal device initiating a slice service request after performing cell reselection based on the slice and / or the accuracy of the access network device quickly identifying the terminal device service when performing random access based on the slice.

[0017] In one possible implementation, after obtaining network slices and third NSAG information supported by the access network device, the method further includes: sending the third NSAG information; receiving second indication information, the second indication information being used to indicate a slice identifier of a candidate second network slice, the candidate second network slice being a network slice that can be used to replace the first network slice when the first network slice is unavailable, and the NSAG information associated with the candidate second network slice is not included in the third NSAG information; sending third indication information in response to the second indication information, the third indication information being used to indicate that NSAG information associated with the candidate second network slice is configured; and obtaining NSAG information associated with the candidate second network slice. The first network device determines to obtain NSAG information associated with the candidate second network slice based on the received second indication information, and then sends the third indication information to obtain NSAG information associated with the candidate second network slice. After obtaining the NSAG information associated with the candidate second network slice, if the first network slice is unavailable during subsequent communication, the NSAG information associated with the second network slice used to replace the first network slice has been obtained by the first network device, thereby facilitating the first network device to send the NSAG information associated with the second network slice to the terminal device.

[0018] In one possible implementation, before sending the third indication information in response to the second indication information, the method further includes: determining an access network device that supports the candidate second network slice. The first network device may send the third indication information to the access network device that supports the candidate second network slice, so that the access network device that supports the candidate second network slice configures the associated NSAG information for the candidate second network slice. Alternatively, the first network device may not determine which access network devices support the candidate second network slice, but instead send the third indication information to multiple access network devices, and the access network devices may determine whether they can configure the associated NSAG information for the candidate second network slice.

[0019] In one possible implementation, the first NSAG information includes NSAG information associated with the candidate second network slice.

[0020] In one possible implementation, the NSAG information associated with the second network slice is included in the third NSAG information. In this implementation, the network device can determine the second network slice used to replace the first network slice from the network slices that are already associated with the NSAG information, thereby facilitating the first network device to provide the NSAG information associated with the second network slice to the terminal device.

[0021] In a second aspect, an embodiment of the present application provides a communication method, which is applied to a first network device, and the method includes: obtaining network slices and third NSAG information supported by the access network device; sending first indication information, wherein the first indication information is used to indicate the NSAG information associated with the configuration of a second network slice, the second network slice is a network slice that replaces the first network slice to provide services to the terminal device, the first network slice belongs to the network slice allowed by the terminal device, and the third NSAG information does not include the NSAG information associated with the second network slice; obtaining the NSAG information associated with the second network slice.

[0022] In one possible implementation, before sending the first indication information, the method further includes: determining an access network device that supports the second network slice.

[0023] In one possible implementation, the method further includes: sending NSAG information associated with the second network slice to the terminal device.

[0024] In a third aspect, an embodiment of the present application provides a communication method, applied to a first network device, the method comprising: obtaining network slices and third NSAG information supported by the access network device; sending the third NSAG information; receiving second indication information, the second indication information including a slice identifier of a candidate second network slice, the candidate second network slice being a network slice that can be used to replace the first network slice when the first network slice is unavailable, and the NSAG information associated with the candidate second network slice is not included in the third NSAG information; sending third indication information in response to the second indication information, the third indication information being used to indicate the configuration of associated NSAG information for the candidate second network slice; and obtaining NSAG information associated with the candidate second network slice.

[0025] In one possible implementation, before sending the third indication information in response to the second indication information, the method also includes: determining an access network device that supports the candidate second network slice.

[0026] In one possible implementation, the method further includes: sending NSAG information associated with the second network slice to the terminal device, where the second network slice belongs to the candidate second network slice.

[0027] In a fourth aspect, an embodiment of the present application provides a communication method, applied to a first network device, the method comprising: obtaining network slices and third NSAG information supported by the access network device; sending the third NSAG information; obtaining a mapping relationship between the first network slice and the second network slice, the NSAG information associated with the second network slice being included in the third NSAG information, the first network slice belonging to a network slice allowed by the terminal device, and the second network slice being a network slice that replaces the first network slice to provide services to the terminal device.

[0028] In a fifth aspect, an embodiment of the present application provides a communication method, which is applied to a second network device, and the method includes: obtaining third NSAG information, the third NSAG information including NSAG information associated with the configuration of one or more network slices supported by the access network device; when the first network slice is unavailable, determining a second network slice, the first network slice belongs to a network slice allowed by the terminal device, the second network slice is a network slice that replaces the first network slice to provide services to the terminal device, and the third NSAG information includes NSAG information associated with the second network slice; sending a mapping relationship between the first network slice and the second network slice.

[0029] In a sixth aspect, an embodiment of the present application provides a communication method, which is applied to a second network device, and the method includes: obtaining third NSAG information, the third NSAG information including NSAG information associated with the configuration of one or more network slices supported by the access network device; determining a candidate second network slice of the first network slice, the candidate second network slice being a network slice that can be used to replace the first network slice when the first network slice is unavailable, and the third NSAG information does not include NSAG information associated with the candidate second network slice; sending second indication information, the second indication information including an identifier of the candidate second network slice, for indicating the acquisition of NSAG information associated with the candidate second network slice.

[0030] In the seventh aspect, an embodiment of the present application provides a communication method, which is applied to an access network device. The method includes receiving first indication information, where the first indication information includes a slice identifier of a second network slice, and the first indication information is used to indicate the configuration of associated NSAG information for the second network slice; configuring the NSAG information associated with the second network slice; and sending the NSAG information associated with the second network slice.

[0031] In one possible implementation, the configuring of the NSAG information associated with the second network slice includes: when determining that the second network slice is supported, configuring the NSAG information associated with the second network slice.

[0032] In an eighth aspect, an embodiment of the present application provides a communication method, which is applied to a terminal device, and the method includes: obtaining a mapping relationship between a first network slice and a second network slice and NSAG information of a first network slice access layer group, wherein the first network slice belongs to a network slice allowed by the terminal device, and the second network slice is a network slice that replaces the first network slice to provide services for the terminal device, and the first NSAG information is NSAG information associated with the network slice configured for the terminal device, and the first NSAG information includes NSAG information associated with the first network slice; determining second NSAG information based on the mapping relationship and the first NSAG information, and the second NSAG information does not include NSAG information associated with the first network slice; and performing cell reselection and / or random access based on the second NSAG information.

[0033] In a possible implementation, the determining of the second NSAG information based on the mapping relationship and the first NSAG information includes: the non-access layer of the terminal device sends a first network slice identifier list and the first NSAG information to the access layer of the terminal device based on the mapping relationship and one or more network slices used for cell reselection and / or random access, wherein the first network slice identifier list includes identifiers of network slices other than the first network slice in the one or more network slices; the access layer of the terminal device determines the second NSAG information based on the first NSAG information and the first network slice identifier list.

[0034] In one possible implementation, the determining of the second NSAG information based on the mapping relationship and the first NSAG information includes: the non-access layer of the terminal device determines the second NSAG information based on the mapping relationship and the first NSAG information; the non-access layer of the terminal device sends the second NSAG information and the slice identifier of one or more network slices for cell reselection and / or random access to the access layer of the terminal device.

[0035] In a possible implementation, the non-access layer of the terminal device determines the second NSAG information based on the mapping relationship and the first NSAG information, including: the non-access layer of the terminal device determines a first network slice identifier list based on the mapping relationship, the first network slice identifier list including identifiers of network slices other than the first network slice in the one or more network slices; the non-access layer of the terminal device determines the second NSAG information based on the first network slice identifier list and the first NSAG information.

[0036] In one possible implementation, the slice identifiers of the one or more network slices do not include the slice identifier of the first network slice.

[0037] In one possible implementation, when the first NSAG information does not include NSAG information associated with the second network slice, the one or more network slices do not include the second network slice.

[0038] In a possible implementation, the determining of the second NSAG information based on the mapping relationship and the first NSAG information includes: the non-access layer of the terminal device sends the mapping relationship, the first NSAG information and the slice identifiers of one or more network slices used for cell reselection and / or random access to the access layer of the terminal device; the access layer of the terminal device determines a first network slice identifier list based on the mapping relationship, the first network slice identifier list including identifiers of network slices other than the first network slice in the one or more network slices; the access layer of the terminal device determines the second NSAG information based on the first network slice identifier list and the first NSAG information.

[0039] In the ninth aspect, an embodiment of the present application provides a communication device, which includes: a processor, the processor is coupled to a memory, the memory is used to store programs or instructions, and when the program or instructions are executed by the processor, the device executes the method of the first aspect and any possible implementation of the first aspect, or executes the method of the second aspect and any possible implementation of the second aspect, or executes the method of the third aspect and any possible implementation of the third aspect, or executes the method of the second aspect and any possible implementation of the second aspect, or executes the method of the fourth aspect and any possible implementation of the fourth aspect.

[0040] In the tenth aspect, an embodiment of the present application provides a communication device, which includes: a processor, the processor is coupled to a memory, the memory is used to store programs or instructions, when the program or instructions are executed by the processor, the device executes the method as in the fifth aspect and any possible implementation of the fifth aspect, or executes the method as in the sixth aspect and any possible implementation of the sixth aspect.

[0041] In the eleventh aspect, an embodiment of the present application provides a communication device, which includes: a processor, the processor is coupled to a memory, the memory is used to store programs or instructions, when the program or instructions are executed by the processor, the device executes the method as in the seventh aspect and any possible implementation method of the seventh aspect.

[0042] In the twelfth aspect, an embodiment of the present application provides a communication device, which includes: a processor, the processor is coupled to a memory, the memory is used to store programs or instructions, when the program or instructions are executed by the processor, the device executes the method as in the eighth aspect and any possible implementation method of the eighth aspect.

[0043] In a thirteenth aspect, a communication system includes the communication device described in the first, second, third, or fourth aspect, and the communication device described in the fifth or sixth aspect. Furthermore, the system may include the communication device described in the seventh aspect and / or the communication device described in the eighth aspect.

[0044] In the fourteenth aspect, an embodiment of the present application provides a chip, comprising: a processor, the processor being coupled to a memory, the memory being used to store instructions, and when the instructions are executed by the processor, the chip implements the methods described in the above-mentioned first to eighth aspects and any one of their implementation methods.

[0045] In a fifteenth aspect, an embodiment of the present application provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to execute the method described in aspects 1 to 8 and any of their implementations.

[0046] In the sixteenth aspect, an embodiment of the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the method described in the first to eighth aspects and any one of their implementations.

[0047] The technical effects that can be achieved in any of the above-mentioned aspects 9 to 16 can refer to the corresponding technical effects that can be achieved in any of the above-mentioned aspects 1 to 8, and the repetitions will not be discussed here. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] FIG1 is a schematic diagram of a 5G architecture provided in an embodiment of the present application;

[0049] FIG2 is a flow chart of a communication method according to an embodiment of the present application;

[0050] FIG3 is a second flow chart of a communication method provided in an embodiment of the present application;

[0051] FIG4 is a third flow chart of a communication method provided in an embodiment of the present application;

[0052] FIG5 is a fourth flow chart of a communication method provided in an embodiment of the present application;

[0053] FIG6 is a fifth flow chart of a communication method provided in an embodiment of the present application;

[0054] FIG7 is a sixth flow chart of a communication method provided in an embodiment of the present application;

[0055] FIG8 is a seventh flow chart of a communication method provided in an embodiment of the present application;

[0056] FIG9 is a flow chart of a communication method according to an embodiment of the present application;

[0057] FIG10 is a ninth flowchart of a communication method according to an embodiment of the present application;

[0058] FIG11 is a tenth flowchart of a communication method provided in an embodiment of the present application;

[0059] FIG12 is a flow chart of a communication method according to an embodiment of the present application;

[0060] FIG13 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0061] FIG14 is a schematic structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0062] Different network slices can be identified and distinguished by single network slice selection assistance information (S-NSSAI). Each S-NSSAI can include the following information:

[0063] 1. Slice / service type (SST), which indicates the characteristics and service type of the network slice;

[0064] 2. Slice Differentiator (SD), as a supplement to SST, can further differentiate multiple network slices that meet the same SST. SD is optional information.

[0065] Network Slice Selection Assistance Information (NSSAI) can represent one or more network slices, such as a list of S-NSSAI. Regarding NSSAI, it can include the following types:

[0066] 1. Subscribed NSSAI: Subscription data belonging to the UE.

[0067] 2. Default NSSAI: Based on the operator's policy, one or more of the NSSAIs subscribed to by the UE may be set as the default NSSAI. If the UE does not carry an allowed NSSAI in the registration request message, and the UE has a default NSSAI, the network side can use the network slice corresponding to the default NSSAI to provide services to the UE.

[0068] 3. Requested NSSAI: This is the allowed NSSAI or configured NSSAI carried by the UE in the registration request message.

[0069] 4. Allowed NSSAI: Indicates one or more S-NSSAIs allowed by the network in the NSSAI requested by the UE. The allowed S-NSSAIs are sent to the UE via the "Allowed NSSAI" information element (IE) in the registration accept message. The allowed S-NSSAIs are supported in the UE's registration area (RA).

[0070] 5. Partially allowed NSSAI: indicates that one or more S-NSSAIs are supported in some tracking areas (TAs) included in the UE's registration area.

[0071] 6. Configured NSSAI: This field indicates the NSSAI configured by the network for the UE. The network-configured NSSAI can be sent to the UE via the "Configured NSSAI" IE in the Registration Accept message. If the UE's configuration changes after registration, the network can notify the UE of the update via a Configuration Update Command.

[0072] The list of network slices (i.e., slice list) supported by the access network device can be pre-configured by the operation administration and maintenance (OAM) with TA as the granularity, that is, the cells within a TA support the same slices. The access network device can report the above-mentioned pre-configured network slice list to the core network when establishing the NG interface with the core network; if the access network device can also support centralized unit / distributed unit (CU / DU) separation, then the DU can first send the network slice list supported by each TA to the CU, and then the CU reports it to the core network.

[0073] When a UE that has subscribed to the network slicing service initially accesses the network, it can initiate a registration request for a specific network slice by sending an RRC setup complete message carrying the requested NSSAI, which is then transparently transmitted to the core network via the access network device (the access network device does not parse the registration request). The core network combines the UE's subscription information (i.e., subscribed NSSAI) in the unified data management (UDM) network element to determine whether the network side (including the radio access network and the core network) allows the network slice requested by the UE to provide services for the UE. If the core network confirms that the current network side can support the services corresponding to the requested NSSAI, it returns the allowed NSSAI and the UE's RA range to the UE through a registration accept message (the RA range can be represented by a tracking area identity list (TA identity list, TAI list)). If the core network confirms that the current network cannot support the services corresponding to some or all of the S-NSSAI in the requested NSSAI, it returns the allowed NSSAI and / or rejected NSSAI (rejected NSSAI) and the UE's RA range to the UE through a registration accept message. When the UE moves within the RA range, it cannot re-initiate a registration request for the rejected NSSAI.

[0074] The UE can initiate a protocol data unit (PDU) session establishment request to the core network based on the allowed NSSAI (through the transparent transmission of NAS messages by the access network device). After the core network determines that it can support the PDU session, it will send a PDU session resource establishment request to the access network device, which will include the session identifier of the PDU session to be established and the associated S-NSSAI. The base station determines that resources can be allocated for the PDU session based on the S-NSSAI associated with the PDU session to be established indicated by the core network, and creates at least one data radio bearer (DRB) corresponding to the PDU session in the air interface.

[0075] The access network device can notify the UE of the cell reselection priority and specific random access parameters for the network slice by broadcasting. Specifically, the cell reselection priority and specific random access parameters for the network slice can be included in the system information block (SIB) 16 and SIB1, respectively. Taking into account that broadcasting based on network slice granularity may bring relatively large overhead to SIB and there are security risks, the concept of network slice access layer group (NSAG) is proposed, that is, one or more network slices are grouped and managed. Specifically, one or more S-NSSAIs assigned to a group are associated with the corresponding NSAG ID, and the association between the NSAG ID and the S-NSSAI is unique in a specific area. The above-mentioned association relationship has the following specific features:

[0076] 1. Bidirectional association, including the NSAG ID value and the related S-NSSAI.

[0077] 2. OAM configures the access network device, which sends the association relationship to the core network through the NG interface. The core network then provides it to the UE via a non-access stratum (NAS) message.

[0078] 3. The granularity of regional validity is TA. When the core network sends the NSAG association relationship to the UE through the NAS message, it can also carry the TA list (ie, TAI list) corresponding to the effective association relationship.

[0079] 4. Allow network slices not to be associated with any NSAG.

[0080] 5. A network slice can be associated with NSAGs belonging to different purposes, that is, different purposes can have their own independent association relationship between NSAG and network slice. For example, network slice 1 (slice#1) can be associated with NSAG#1 for cell reselection and NSAG#2 for random access at the same time; however, for the same purpose, a network slice is not allowed to be associated with multiple NSAGs.

[0081] 6. You can configure the corresponding NSAG priority for each NSAG.

[0082] When a UE in idle or inactive state needs to perform a cell reselection procedure based on NSAG due to mobility, the cell reselection priority needs to be derived based on the following:

[0083] 1. In the NSAG information provided by the non-access stratum (NAS), the NSAG information associated with one or more network slices provided by the NAS for cell reselection. Currently, after receiving the NSAG information supported in the TA sent by the access network device, the access and mobility management function (AMF) network element can send the NSAG information associated with the UE's configured NSSAI to the UE's non-access stratum through the UE's registration process. The UE non-access stratum (i.e., UE NAS) then transparently transmits the above NSAG information to the UE access stratum (i.e., UE AS). In addition, the UE non-access stratum can also send the requested NSSAI, allowed NSSAI, and partially allowed NSSAI to the UE access stratum (i.e., the non-access stratum provides the access stratum with one or more network slices for cell reselection). Then, the UE access stratum can determine the NSAG information for cell reselection based on the one or more network slices and NSAG information used for cell reselection.

[0084] 2. Slice information (slice info) in broadcast or RRC dedicated messages. This slice information is defined in SIB16 or RRC release messages, including the NSAG IDs supported by the frequency points of the current serving cell and neighboring cells, as well as the corresponding supported frequencies and cell reselection priorities. In other words, the network side configures the cell reselection parameters dedicated to the network slice based on the NSAG ID.

[0085] During the random access process of a UE in an idle or inactive state, in order to enable the access network device to quickly identify the network slice service, the public random access channel (RACH) resources of the air interface can be divided into different parts (partitions), and each RACH partition is configured with a set of RACH resources, which is applicable to one or more NSAG IDs configured on the network side. During the initialization process of the random access parameters, corresponding random access priorities are configured for different random access types. When the UE needs to perform random access, the UE access layer can determine the corresponding random access priority based on the NSAG information for random access provided by the UE non-access layer and the one or more network slices that trigger the random access.

[0086] When the network slice deployed in the core network is congested or unavailable, in order to ensure the service needs of the UE, an alternative S-NSSAI (alternative S-NSSAI) is introduced to replace the allowed S-NSSAI where there is no resource or resource congestion on the core side to provide services to the UE. Among them, the alternative S-NSSAI can be supported within the registration area of ​​the UE; when the UE indicates support for the alternative S-NSSAI, if a certain allowed S-NSSAI is unavailable or congested (then the unavailable allowed S-NSSAI can also be called the original S-NSSAI), the policy control function network element (PCF), the network slice selection function network element (NSSF) or the OAM can provide the corresponding alternative S-NSSAI to the AMF, and the AMF sends the mapping relationship between the alternative S-NSSAI and the original S-NSSAI to the UE through a NAS message, and updates the NSAG information associated with the alternative S-NSSAI to the UE, and adds the alternative S-NSSAI to the UE's allowed NSSAI and / or configured NSSAI (if the alternative S-NSSAI did not previously belong to the above two NSSAIs).

[0087] The above mapping relationship can also be sent to the UE in advance without relying on establishing a PDU session associated with the original S-NSSAI to trigger the sending of the mapping relationship. After receiving the mapping relationship, if the UE needs to initiate a PDU session associated with the original S-NSSAI, it will carry both the original S-NSSAI and the alternative S-NSSAI in the PDU session establishment request. After receiving the PDU session establishment request, the AMF will send both S-NSSAIs to the SMF, and the SMF will determine to establish a PDU session associated with the alternative S-NSSAI, thereby completing the network slice replacement process on the network side.

[0088] When the AMF determines to send the mapping relationship between the alternative S-NSSAI and the original S-NSSAI to the UE, if the alternative S-NSSAI and the original S-NSSAI are both associated with NSAGs on the radio access network side, since the above two S-NSSAIs both belong to the allowed NSSAI of the UE, the UE will consider the NSAG information associated with the above two S-NSSAIs when performing the cell reselection process based on network slicing. However, the UE may reselect to a cell that does not support the alternative S-NSSAI when performing cell reselection based on the NSAG information corresponding to the original S-NSSAI, resulting in the UE being unable to obtain the data service originally provided by the network slice corresponding to the original S-NSSAI in the reselected cell. Because after the UE reselects to a cell that does not support alternative S-NSSAI, if the UE requests to establish a PDU session associated with the original S-NSSAI, the PDU session establishment request will include the original S-NSSAI and the alternative S-NSSAI. However, since the reselected cell does not support alternative S-NSSAI, the PDU session establishment on the network side will fail, resulting in the UE being unable to obtain the data service originally provided by the network slice corresponding to the original S-NSSAI.

[0089] In addition, if the alternative S-NSSAI has no associated NSAG on the radio access network side (that is, the alternative S-NSSAI is not divided into any NSAG on the radio access network side), the UE cannot subsequently perform cell reselection and / or random access based on the NSAG associated with the alternative S-NSSAI.

[0090] It can be seen that when a UE in an idle or inactive state performs cell reselection and / or random access based on a network slice, it is necessary to obtain one or more network slices used for cell reselection and / or random access and the NSAG information associated with the network slice. When the network slice deployed in the core network corresponding to the original S-NSSAI is congested or unavailable, and the alternative S-NSSAI has no associated NSAG, it may cause the UE to perform cell reselection to a cell that does not support the alternative S-NSSAI and then request the service corresponding to the original S-NSSAI to fail, or when the UE performs random access in a cell that does not support the alternative S-NSSAI, the access network device cannot quickly identify the service initiated by the UE.

[0091] In view of this, an embodiment of the present application provides a communication method for providing a usable network slice to a terminal device in an idle or inactive state when a network slice deployed in a core network is congested or unavailable, so as to ensure the business needs of the terminal device.

[0092] The communication method provided in the embodiment of the present application can be applied to wireless communication systems, such as 5G communication systems, 6G communication systems or other communication systems in the future. Figure 1 exemplarily provides a schematic diagram of a 5G architecture applicable to an embodiment of the present application. As shown in Figure 1, the network architecture may include UE, RAN, AMF, session management function (session management function, SMF), PCF, unified data management (unified data management, UDM), network exposure function (network exposure function, NEF), network storage function (network repository gunction, NRF), network slice selection function (network slice selection function, NSSF), application function (application function, AF), data network (data network, DN), etc.

[0093] Radio access network (RAN) equipment is used to implement functions related to wireless access. The radio access network can also be called access network equipment or base station, which is used to access the terminal to the wireless network. The radio access network can be a base station, an evolved nodeB (eNodeB) in an LTE system or an evolved LTE system (LTE-advanced, LTE-A), a next-generation NodeB (gNB) in a 5G communication system, a transmission reception point (TRP), a baseband unit (BBU), a WiFi access point (AP), a base station in a future mobile communication system, or an access node in a WiFi system. The radio access network can also be a module or unit that completes some of the functions of a base station, for example, it can be a CU, DU, CU-control plane (CP), CU-user plane (UP), or a radio unit (RU). RAN can also be an open access network (open RAN, O-RAN or ORAN). In the ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. The embodiments of this application do not limit the specific technology and specific equipment form adopted by the radio access network. In the following embodiments, the radio access network is referred to as RAN for example.

[0094] A terminal device is a device with wireless transceiver capabilities. The terminal device is connected to a wireless access network device via wireless means, thereby accessing a communication system. The terminal device may also be referred to as a terminal, UE, mobile station, mobile terminal, etc. The terminal device may be a mobile phone, a tablet computer, a computer with wireless transceiver capabilities, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a whole vehicle, a wireless communication module in a whole vehicle, a telematics box (T-box), a roadside unit (RSU), a terminal device in unmanned driving, a terminal device in an Internet of Things (IoT) network, a terminal device in remote medical care, a terminal device in a smart grid, a terminal device in transportation safety, a terminal device in a smart city, or a terminal device in a smart home, etc., and the embodiments of the present application are not limited thereto. For the convenience of description, the following embodiments of the present application will be illustrated using UE as an example.

[0095] The mobility management network element is a control plane network element provided by the operator network, responsible for access control and mobility management of terminal devices accessing the operator network, such as mobile state management, allocation of user temporary identity, authentication and authorization of users, etc. In 5G, the mobility management network element can be AMF. In future communication systems, the mobility management network element can still be AMF or have other names, which are not limited in this application. For the convenience of description, the following embodiments of this application will be illustrated by AMF.

[0096] The session management network element is a control plane network element provided by the operator network, which is responsible for managing the PDU session of the terminal device. The PDU session is a channel for transmitting PDUs, and the terminal device needs to transmit PDUs to each other with the DN through the PDU session. The SMF network element is responsible for establishing, maintaining and deleting the PDU session. The session management network element includes session management (such as session establishment, modification and release, including tunnel maintenance between user plane network elements and access network equipment), selection and control of user plane network elements, service and session continuity (SSC) mode selection, roaming and other session-related functions. In 5G, the session management network element can be SMF. In future communication systems, the session management network element can still be SMF, or have other names, which are not limited in this application.

[0097] The policy control network element (PCNE) is a control plane function provided by the operator, which is used to provide PDU session policies to the session management network element. Policies may include charging-related policies, QoS-related policies, and authorization-related policies. In 5G, the policy control network element may be a PCF. In future communication systems, the policy control network element may still be a PCF or have other names, which are not limited in this application. For ease of description, the following embodiments of this application will use the PCF as an example.

[0098] The network slice selection function network element is used to select the set of network slice instances to serve the UE; determine the allowed NSSA / configured NSSAI, and can also determine the AMF set used to serve the UE, determine the list of candidate AMFs by querying the NRF, determine whether the S-NSSAI must be replaced, and provide the AMF with an indication that the S-NSSAI is unavailable and the corresponding replacement S-NSSAI (that is, to determine the alternative S-NSSAI), etc.

[0099] It should be understood that Figure 1 is only an example of an applicable network architecture, and the network architecture of actual application may include more or fewer network elements than Figure 1. For example, the architecture may also include a network data analytics function (NWDAF), a unified data repository (UDR), an authentication server function (AUSF), etc.

[0100] FIG2 is a flow chart of a communication method provided in an embodiment of the present application. As shown in the figure, the method may include the following steps:

[0101] Step 201: A first network device determines that a first network slice is unavailable, where the first network slice is a network slice allowed by a terminal device.

[0102] The first network device can be the AMF in the 5G communication system, or it can be a network element used for mobility management in a future communication system.

[0103] In an embodiment of the present application, the network slice deployed in the core network is unavailable, which may mean that the network slice has no available resources, or it may mean that the resources of the network slice are congested. Although some resources are still available, they cannot meet the business needs of the terminal device.

[0104] The terminal device may be in an idle state or an inactive state, and the network side (including the wireless access network and the core network) has determined the allowed NSSAI for the terminal device, that is, it has determined one or more network slices that the terminal device is allowed to use. After performing cell reselection and / or random access, the terminal device in an idle or inactive state can request to establish a PDU session associated with the allowed network slice. However, if the first network slice of the one or more network slices allowed by the terminal device is currently unavailable, then after the terminal device performs cell reselection and / or random access, it may not be possible to request to establish a PDU session associated with the first network slice, thereby failing to obtain the service data provided by the first network slice; or, the access network device may not be able to quickly identify the service initiated by the terminal device, thereby failing to perform corresponding processing for different service requirements.

[0105] Therefore, when the first network slice deployed in the core network is unavailable, the first network device executes step 202 so that the terminal device can continue to obtain service data, or the access network device can quickly identify the service initiated by the terminal device.

[0106] Step 202: The first network device sends the mapping relationship between the first network slice and the second network slice and the first NSAG information to the terminal device. The first NSAG information does not include the NSAG information associated with the first network slice.

[0107] The second network slice is a network slice that can replace the first network slice to provide services to the terminal device; the mapping relationship between the first network slice and the second network slice is used to instruct the terminal device to replace the first network slice with the second network slice. When the terminal device needs to establish a PDU session associated with the first network slice, according to the above mapping relationship, the identifiers of the first network slice and the second network slice are carried in the establishment request, so that the network side establishes a PDU session associated with the second network slice and provides service data to the terminal device.

[0108] The first NSAG information may include NSAG information associated with the network slices supported by the access network device, but does not include NSAG information associated with the first network slice. Specifically, the first network device may pre-acquire NSAG information associated with the network slices supported by the access network device; if the acquired NSAG information associated with the network slices supported by the access network device includes NSAG information associated with the first network slice, the first network device removes the NSAG information associated with the first network slice when sending the first NSAG information to the terminal device, so that the first NSAG information sent to the terminal device does not include the NSAG information associated with the first network slice.

[0109] The mapping relationship and the first NSAG information may be sent to the terminal device via the same message, or may be sent to the terminal device via different messages. When sent to the terminal device via different messages, the order of sending the mapping relationship and sending the first NSAG is not limited in this embodiment of the present application.

[0110] Step 203: The terminal device performs cell reselection and / or random access according to the first NSAG information.

[0111] When a terminal device in an idle state or an inactive state needs to perform cell reselection and / or random access, the terminal device may perform cell reselection and / or random access according to the mapping relationship and the first NSAG information sent by the first network device. It should be understood that after receiving the mapping relationship and the first NSAG information sent by the first network device, the terminal device does not necessarily perform cell reselection and / or random access immediately, and the embodiment of the present application does not limit the timing of performing cell reselection and / or random access.

[0112] In the above method, after determining that the first network slice allowed by the terminal device is unavailable, the first network device sends the mapping relationship between the first network slice and the second network slice and the first NSAG information to the terminal device. Since the first NSAG information does not include the NSAG information associated with the first network slice, the terminal device will not reselect to a cell that only supports the first network slice when performing cell reselection, which helps the terminal device to perform network slice-based cell reselection based on the NSAG associated with the second network slice, and helps to improve the success rate of the terminal device initiating a slice service request after performing network slice-based cell reselection; or, helps the terminal device to perform network slice-based random access based on the NSAG associated with the second network slice, and helps to improve the accuracy of the access network device in quickly identifying the terminal device service when the terminal device performs random access based on the network slice.

[0113] In one possible implementation, when the first network device determines in step 201 that the first network slice is unavailable, it may determine that the first network slice is unavailable based on the received mapping relationship between the first network slice and the second network slice after receiving the mapping relationship. In other words, the first network device may not directly determine whether the network slice is available, or even directly determine the second network slice to replace the first network slice, but instead determines that the first network slice is unavailable based on the received mapping relationship between the first network slice and the second network slice. The above mapping relationship may be sent by the second network device to the first network device; optionally, the second network device may be a PCF, NSSF, or OAM.

[0114] Optionally, after the first network device executes step 202, if the first network slice is restored to an available state, that is, the resources of the first network slice can meet the business needs of the terminal device, then the first network device can also send a second NSAG information to the terminal device, wherein the second NSAG information includes the NSAG information associated with the first network slice.

[0115] In a specific embodiment, when the first network slice is restored to an available state on the core network side, the first network device may send a deletion indication message in addition to sending the second NSAG information. The deletion indication message is used to instruct the terminal device to delete the mapping relationship between the first network slice and the second network slice. After receiving the deletion indication message and the second NSAG message, if the terminal device needs to perform cell reselection and / or random access, it performs cell reselection and / or random access according to the second NSAG information; since the second NSAG information includes the NSAG information associated with the first network slice and the mapping relationship between the first network slice and the second network slice is deleted, the terminal device can reselect to the cell that supports the first network slice, and thus can request to establish a PDU session associated with the first network slice. If the terminal device has already established a PDU session associated with the second network slice, the terminal device can also release the PDU session associated with the second network slice and request to establish a PDU session associated with the first network slice; alternatively, the terminal device can perform random access based on the NSAG associated with the first network slice, thereby enabling the access network device to quickly identify the access service initiated by the terminal device.

[0116] In one possible implementation, the first network device may further obtain the network slices supported by the access network device and third NSAG information, where the third NSAG information is the NSAG information associated with the network slice by the access network device. For example, after the access network device is online, it may send the network slices it supports and the configured third NSAG information to the first network device through the NG interface, so that the first network device can subsequently instruct the terminal device to replace the unavailable network slice based on the network slices it supports and the third NSAG information.

[0117] Since the current communication protocol allows a network slice not to be associated with any NSAG, the third NSAG information may include the NSAGs associated with one or more network slices among the network slices supported by the access network device, but does not necessarily include the NSAG information associated with each network slice supported by the access network device. For example, the access network device reports that the supported network slices include network slice 1, network slice 2, and network slice 3, and the third NSAG information reported includes the NSAG information associated with network slice 1 and the NSAG information associated with network slice 2. Since the access network device does not configure the associated NSAG information for network slice 3, the third NSAG information reported to the first network device does not include the NSAG information associated with network slice 3.

[0118] However, if the third NSAG information obtained by the first network device does not include the NSAG information associated with the second network slice used to replace the first network slice, then the first NSAG information sent by the first network device to the terminal device cannot include the NSAG information associated with the second network slice. In this case, it is impossible to ensure that the terminal device performs cell reselection and / or random access based on the NSAG associated with the second network slice, and it is impossible to ensure the success rate of the terminal device initiating a slice service request after performing cell reselection based on the network slice, and it is impossible to ensure the accuracy of the access network device's rapid identification of the terminal device service when the terminal device performs random access based on the network slice. In order to solve this problem, the embodiments of the present application provide the following multiple ways to enable the first network device to obtain the NSAG information associated with the second network slice.

[0119] Method 1: The first network device determines that the third NSAG information obtained does not include the NSAG information associated with the second network slice, and instructs the access network device to associate NSAG information with the second network slice.

[0120] Optionally, after receiving the mapping relationship between the first network slice and the second network slice sent by the second network device, the first network device can determine whether the acquired third NSAG information includes the NSAG information associated with the second network slice; if not, the first network device instructs the access network device to associate the NSAG information with the second network slice.

[0121] Alternatively, after obtaining the network slices and third NSAG information supported by the access network device, the first network device may determine whether the access network device has associated an NSAG for each network slice. If there is a network slice that is not associated with NSAG information, the first network device instructs the access network device to associate an NSAG for the network slice that is not associated with NSAG information. Therefore, the first network device can obtain the NSAG information associated with each network slice supported by the access network device, which also includes the NSAG information associated with the second network slice used to replace the first network slice in the subsequent communication process.

[0122] When a first network device instructs an access network device to associate NSAG information with a second network slice, it may directly send first indication information to the access network device, where the first indication information indicates that the NSAG information is associated with the second network slice. Alternatively, the first network device may send the first indication information to a third network device, where the first indication information similarly indicates that the NSAG information is associated with the second network slice. Upon receiving the first indication information, the third network device instructs the access network device to associate NSAG information with the second network slice. The third network device may be an OAM. The third network device and the second network device may be the same network element or different network elements, as is not limited in this embodiment of the present application. For example, the first network device is an AMF. The AMF sends indication information 1 to OAM1, which manages the AMF, indicating that the NSAG information is associated with the second network slice. OAM1 sends indication information 2 to OAM2, which manages the gNB, indicating that the NSAG information is associated with the second network slice. OAM2 sends indication information 3 to the gNB, indicating that the NSAG information is associated with the second network slice. OAM1, which manages the AMF, and OAM2, which manages the gNB, may be the same network element or different network elements.

[0123] Optionally, when the first network device sends the first indication information to the access network device, it may first determine the access network device that supports the second network slice, and then send the first indication information to the access network device that supports the second network slice. Alternatively, the first network device may not determine which access network devices support the second network slice, and send the first indication information to multiple access network devices; the access network device that receives the first indication information determines whether it supports the second network slice, and if so, associates NSAG information with the second network slice; if not, no NSAG association is required.

[0124] Similarly, when the first network device sends the first indication information to the third network device, the way in which the third network device instructs the access network device to associate NSAG for the second network slice is similar to the way in which the first network device directly sends the first indication information to the access network device. The third network device can send the indication information to the access network device that supports the second network slice, or it is not necessary to determine the access network device that supports the second network slice. After receiving the indication information, the access network device determines whether to associate NSAG information for the second network slice.

[0125] After receiving the indication information sent by the first network device or the third network device, the access network device that supports the second network slice associates NSAG information for the second network slice and reports the NSAG information associated with the second network slice to the first network device. Optionally, when the access network device receives the indication information sent by the first network device, it can directly send the NSAG information associated with the second network slice to the first network device; when the access network device receives the indication information sent by the third network device, it can send the NSAG information associated with the second network slice to the third network device, and the third network device will send the NSAG information associated with the second network slice to the first network device, or the access network device can also directly send the NSAG information associated with the second network slice to the first network device.

[0126] After obtaining the NSAG information associated with the second network slice, the first network device can carry the NSAG information associated with the second network slice in the first NSAG information and send it to the terminal device, so that the terminal device can reselect and / or access the cell supporting the second network slice based on the NSAG information associated with the second network slice.

[0127] In order to more clearly understand the above-mentioned method 1, an example is given below in conjunction with Figure 3. In the specific embodiment shown in Figure 3, the communication method provided in the embodiment of the present application may include the following steps:

[0128] Step 301: The gNB sends the network slices supported by the gNB and the third NSAG information to the AMF.

[0129] The gNB is the access network device, and the AMF is the first network device. Step 301 can be performed after the gNB goes online.

[0130] Assume that the gNB supports network slice 1 (S1), network slice 2 (S2) and network slice 3 (S3), and the gNB associates NSAG ID1 for S1 and S2, but does not associate NSAG for S3; then the supported network slices sent by the gNB to the AMF include S1, S2 and S3, and the third NSAG information includes the association relationship between S1, S2 and NSAG ID1, but does not include the NSAG information associated with S3.

[0131] Step 302: NSSF detects that S1 is unavailable, determines that S3 will replace S1 to provide business services, and sends the mapping relationship between S1 and S3 to AMF.

[0132] For example, NSSF detects that S1 is congested on the core network side and the remaining resources cannot meet the service needs of the UE. Therefore, NSSF determines that S3 replaces S1 to provide service for the UE, that is, determines the mapping relationship between S1 and S3.

[0133] The above-mentioned NSSF may also be replaced by PCF or OAM, that is, the above-mentioned second network device.

[0134] Step 303: The AMF determines that the third NSAG information does not include the NSAG information associated with S3, and sends a first indication message to the gNB. The first indication message is used to instruct the gNB to configure the NSAG information associated with S3.

[0135] After receiving the mapping relationship between S1 and S3, the AMF determines that S1 is currently unavailable and S3 replaces S1 to provide business services for the UE; however, the third NSAG information previously obtained by the AMF does not include the NSAG information associated with S3. Therefore, it needs to obtain the NSAG information associated with S3, so it sends a first indication message to the gNB to enable the gNB to configure the associated NSAG information for S3.

[0136] Exemplarily, the AMF may send the first indication information to the gNB through an AMF configuration update message (AMF configuration update), an initial context setup request (initial context setup request), etc.

[0137] Step 304: The gNB configures the NSAG information associated with S3 and sends the NSAG information associated with S3 to the AMF.

[0138] For example, the gNB may send the NSAG information associated with S3 to the AMF via a RAN configuration update message and an AMF configuration update ack message.

[0139] Step 305: The AMF sends the mapping relationship between S1 and S3 and the first NSAG information to the UE.

[0140] The first NSAG information includes NSAG information associated with S3, but does not include NSAG information associated with S1.

[0141] Step 306: When the UE needs to perform cell reselection and / or random access, the cell reselection and / or random access is performed according to the mapping relationship between S1 and S3 and the first NSAG information.

[0142] Since the first NSAG information does not include the NSAG information associated with S1, the UE will not reselect and / or access the cell that only supports S1; and since the first NSAG information includes the NSAG information associated with S3, the UE can reselect and / or access the cell that supports S3, thereby obtaining business services through S3.

[0143] Method 2: The second network device instructs the first network device to obtain the NSAG information associated with the candidate second network slice, and the first network device instructs the access network device to associate the NSAG information with the candidate second network slice.

[0144] After obtaining the third NSAG information, the first network device may send the obtained third NSAG information to the second network device. The second network device may estimate the network slice that may become unavailable, that is, determine a candidate first network slice, and determine a network slice that can replace the candidate first network slice for the candidate first network slice. Alternatively, the second network device may not estimate the network slice that may become unavailable, but instead treat each network slice as a candidate first network slice and determine a network slice that can replace the candidate first network slice. The candidate first network slice is a network slice supported by the core network or a network slice supported by the first network device.

[0145] Among the network slices that can replace the candidate first network slice, a network slice that is not associated with NSAG information can be referred to as a candidate second network slice. The second network device can send second indication information to the first network device, where the second indication information includes a slice identifier of the candidate second network slice to instruct the first network device to obtain the NSAG associated with the candidate second network slice. After receiving the second indication information, the first network device sends third indication information to indicate that the candidate second network slice is to be associated with NSAG information.

[0146] When the first network device sends the third indication information, the third indication information may be sent directly to the access network device, or the third indication information may be sent to a third network device, so that the third network device indicates that the access network device is associated with the NSAG information as a candidate second network slice. The third network device may be an OAM.

[0147] The first network device may first determine the access network device that supports the candidate second network slice, and then send the third indication information to the access network device that supports the candidate second network slice; or, the first network device may not determine the access network device that supports the candidate second network slice, and send the third indication information to multiple access network devices, and the access network device that receives the third indication information shall determine whether it supports the candidate second network slice, and if so, associate the NSAG information with the candidate second network slice.

[0148] Similarly, when the first network device sends the third indication information to the third network device, the third network device indicates the access network device to associate the NSAG with the candidate second network slice. This is similar to the way the first network device directly sends the third indication information to the access network device. The third network device can send the indication information to the access network device that supports the candidate second network slice, or it is not necessary to determine the access network device that supports the candidate second network slice. After receiving the indication information, the access network device determines whether to associate the NSAG information with the candidate second network slice.

[0149] After receiving the indication information sent by the first network device or the third network device, the access network device that supports the candidate second network slice associates NSAG information for the candidate second network slice and reports the NSAG information associated with the candidate second network slice to the first network device. Optionally, when the access network device receives the third indication information sent by the first network device, it can directly send the NSAG information associated with the candidate second network slice to the first network device; when the access network device receives the indication information sent by the third network device, it can send the NSAG information associated with the candidate second network slice to the third network device, and the third network device will send the NSAG information associated with the candidate second network slice to the first network device, or the access network device can also directly send the NSAG information associated with the candidate second network slice to the first network device.

[0150] After obtaining the NSAG information associated with the candidate second network slice, the first network device may store the NSAG information associated with the candidate second network slice. When the first network device determines that there is an unavailable first network slice, since the first network device has obtained the NSAG information associated with the network slice that can replace the first network slice, the first network device has also obtained the NSAG information associated with the second network slice. The NSAG information associated with the second network slice may be carried in the first NSAG information and sent to the terminal device, so that the terminal device can reselect and / or access the cell that supports the second network slice according to the NSAG information associated with the second network slice.

[0151] In order to more clearly understand the above-mentioned method 1, an example is given below in conjunction with Figure 4. In the specific embodiment shown in Figure 4, the communication method provided in the embodiment of the present application may include the following steps:

[0152] Step 401: The gNB sends the network slices supported by the gNB and the third NSAG information to the AMF.

[0153] The gNB is the access network device, and the AMF is the first network device. Step 401 can be performed after the gNB goes online.

[0154] Assume that the gNB supports network slice 1 (S1), network slice 2 (S2) and network slice 3 (S3), and the gNB associates NSAG ID1 for S1 and S2, but does not associate NSAG for S3; then the supported network slices sent by the gNB to the AMF include S1, S2 and S3, and the third NSAG information includes the association relationship between S1, S2 and NSAG ID1, but does not include the NSAG information associated with S3.

[0155] Step 402: AMF sends the third NSAG information to NSSF.

[0156] Step 403: The NSSF determines that S1 will become unavailable, and determines that S2 and S3 can replace S1, but the third NSAG information does not include the NSAG information associated with S3.

[0157] Step 404: NSSF sends a second indication message to AMF, where the second indication message includes the slice identifier of S3.

[0158] Since the third NSAG information does not include the NSAG information associated with S3, it is necessary to obtain the NSAG information associated with S3. Therefore, the second indication information sent by NSSF to AMF contains the slice identifier of S3, so that AMF obtains the NSAG information associated with S3.

[0159] Step 405: The AMF sends first indication information to the gNB, where the first indication information is used to indicate the NSAG information associated with the S3 configuration.

[0160] Exemplarily, the AMF may send the first indication information to the gNB through an AMF configuration update message (AMF configuration update), an initial context setup request (initial context setup request), etc.

[0161] Step 406: The gNB configures the NSAG information associated with S3 and sends the NSAG information associated with S3 to the AMF.

[0162] For example, the gNB may send the NSAG information associated with S3 to the AMF via a RAN configuration update message and an AMF configuration update ack message.

[0163] Step 407: When S1 is unavailable, NSSF determines that S3 will replace S1 to provide business services and sends the mapping relationship between S1 and S3 to AMF.

[0164] Step 408: The AMF sends the mapping relationship between S1 and S3 and the first NSAG information to the UE.

[0165] The first NSAG information includes NSAG information associated with S3, but does not include NSAG information associated with S1.

[0166] The above-mentioned NSSF may also be replaced by PCF or OAM, that is, the above-mentioned second network device.

[0167] Step 409: When the UE needs to perform cell reselection and / or random access, the cell reselection and / or random access is performed according to the mapping relationship between S1 and S3 and the first NSAG information.

[0168] Since the first NSAG information does not include the NSAG information associated with S1, the UE will not reselect and / or access the cell that only supports S1; and since the first NSAG information includes the NSAG information associated with S3, the UE can reselect and / or access the cell that supports S3, thereby obtaining business services through S3.

[0169] Method three: The second network device determines the second network slice from the network slice associated with NSAG information.

[0170] After obtaining the third NSAG information, the first network device can send the obtained third NSAG information to the second network device. When the second network device detects that the first network slice is unavailable, it determines, based on the obtained third NSAG information, a second network slice to replace the first network slice from the network slices associated with NSAG information. Therefore, the first network device has already obtained the NSAG information associated with the second network slice determined by the second network device, and does not need to instruct the access network device to associate NSAG information with the second network slice.

[0171] The above implementation method can simplify the operation of the first network device and the access network device, and there is no need to associate NSAG information with the second network slice when the first network slice is unavailable or is about to be unavailable.

[0172] In order to more clearly understand the above-mentioned method 1, an example is given below in conjunction with Figure 5. In the specific embodiment shown in Figure 5, the communication method provided in the embodiment of the present application may include the following steps:

[0173] Step 501: The gNB sends the network slices supported by the gNB and the third NSAG information to the AMF.

[0174] The gNB is the access network device, and the AMF is the first network device. Step 501 can be performed after the gNB goes online.

[0175] Assume that the gNB supports network slice 1 (S1), network slice 2 (S2) and network slice 3 (S3), and the gNB associates NSAG ID1 for S1 and S2, but does not associate NSAG for S3; then the supported network slices sent by the gNB to the AMF include S1, S2 and S3, and the third NSAG information includes the association relationship between S1, S2 and NSAG ID1, but does not include the NSAG information associated with S3.

[0176] Step 502: NSSF detects that S1 is unavailable and determines that both S2 and S3 can replace S1. However, the third NSAG information includes the NSAG information associated with S2 but does not include the NSAG information associated with S3. NSSF determines that S2 replaces S1 to provide business services and sends the mapping relationship between S1 and S2 to AMF.

[0177] The above-mentioned NSSF may also be replaced by PCF or OAM, that is, the above-mentioned second network device.

[0178] Step 503: The AMF sends the mapping relationship between S1 and S2 and the first NSAG information to the UE.

[0179] The first NSAG information includes NSAG information associated with S2, but does not include NSAG information associated with S1.

[0180] Step 504: When the UE needs to perform cell reselection and / or random access, the cell reselection and / or random access is performed according to the mapping relationship between S1 and S2 and the first NSAG information.

[0181] Since the first NSAG information does not include the NSAG information associated with S1, the UE will not reselect and / or access the cell that only supports S1; and since the first NSAG information includes the NSAG information associated with S2, the UE can reselect and / or access the cell that supports S2, thereby obtaining business services through S2.

[0182] An embodiment of the present application also provides a communication method for enabling a first network device to obtain more comprehensive NSAG information, so that when the terminal device performs cell reselection and / or random access, the terminal device can provide the NSAG information associated with the replacement network slice to the terminal device.

[0183] FIG6 is a flow chart of a communication method provided in an embodiment of the present application. As shown in the figure, the method may include the following steps:

[0184] Step 601: The first network device obtains the network slices and third NSAG information supported by the access network device.

[0185] The first network device can be the AMF in the 5G communication system, or it can be a network element used for mobility management in a future communication system.

[0186] The first network device can obtain the network slices and third NSAG information supported by the access network device, where the third NSAG information is the NSAG information associated with the network slice by the access network device. For example, after the access network device is online, it can send the network slices it supports and the configured third NSAG information to the first network device through the NG interface, so that the first network device can subsequently instruct the terminal device to replace the unavailable network slice based on the network slices it supports and the third NSAG information.

[0187] Since the current communication protocol allows a network slice not to be associated with any NSAG, the third NSAG information may include the NSAGs associated with one or more network slices among the network slices supported by the access network device, but does not necessarily include the NSAG information associated with each network slice supported by the access network device. For example, the access network device reports that the supported network slices include network slice 1, network slice 2, and network slice 3, and the third NSAG information reported includes the NSAG information associated with network slice 1 and the NSAG information associated with network slice 2. Since the access network device does not configure the associated NSAG information for network slice 3, the third NSAG information reported to the first network device does not include the NSAG information associated with network slice 3.

[0188] Step 602: The first network device sends a first indication message, where the first indication message is used to indicate the NSAG information associated with the second network slice configuration.

[0189] Among them, the second network slice is a network slice that can replace the first network slice to provide services to the terminal device, the first network slice belongs to the network slice allowed by the terminal device, and the third NSAG information obtained by the first network device does not include the NSAG information associated with the second network slice.

[0190] In one possible implementation, the second network slice is a network slice that is determined to replace the first network slice when the first network slice deployed in the core network is unavailable. When determining that the first network slice is unavailable and the second network slice replaces the first network slice, the first network device can determine whether the acquired third NSAG information contains the NSAG information associated with the second network slice. If not, the above step 602 is executed. If the first network device does not acquire the NSAG information associated with the second network slice, the first network device cannot send the NSAG information associated with the second network slice to the terminal device, and thus cannot guarantee the terminal device's reselection and / or random access to the cell supporting the second network slice, and thus cannot guarantee the success rate of the terminal device initiating a slice service request after performing a cell reselection based on the network slice, nor can it guarantee the accuracy of the access network device's rapid identification of the terminal device's service when the terminal device performs random access based on the network slice. Therefore, the first network device needs to acquire the NSAG information associated with the second network slice.

[0191] For example, the first network device receives the mapping relationship between the first network slice and the second network slice sent by the second network device. The first network device can determine that the first network slice is unavailable based on the mapping relationship and replace the first network slice with the second network slice; then the first network device further determines whether the third NSAG information obtained contains the NSAG information associated with the second network slice. If not, the above step 602 is executed.

[0192] In another possible implementation, the second network slice is a candidate second network slice that can replace the first network slice when the first network slice deployed in the core network is unavailable. That is, the current first network slice may not have entered an unavailable state. If the first network slice enters an unavailable state, the second network slice will be determined from one or more network slices that can replace the first network slice. Among the one or more network slices that can replace the candidate first network slice, a network slice that does not have associated NSAG information can be called a candidate second network slice, and the first network device needs to obtain the NSAG information associated with the candidate second network slice.

[0193] The first network device may directly send the first indication information to the access network device, where the first indication information is used to indicate that the NSAG information is associated with the second network slice. Alternatively, the first network device may also send the first indication information to a third network device, where the first indication information is similarly used to indicate that the NSAG information is associated with the second network slice. Upon receiving the first indication information, the third network device instructs the access network device to associate the NSAG information with the second network slice. The third network device may be an OAM.

[0194] Optionally, when the first network device sends the first indication information to the access network device, it may first determine the access network device that supports the second network slice, and then send the first indication information to the access network device that supports the second network slice. Alternatively, the first network device may not determine which access network devices support the second network slice, and send the first indication information to multiple access network devices; the access network device that receives the first indication information determines whether it supports the second network slice, and if so, associates NSAG information with the second network slice; if not, no NSAG association is required.

[0195] Exemplarily, the first network device may send the first indication information to the access network device through an AMF configuration update message (AMF configuration update), an initial context setup request (initial context setup request), etc.

[0196] Similarly, when the first network device sends the first indication information to the third network device, the way in which the third network device instructs the access network device to associate NSAG for the second network slice is similar to the way in which the first network device directly sends the first indication information to the access network device. The third network device can send the indication information to the access network device that supports the second network slice, or it is not necessary to determine the access network device that supports the second network slice. After receiving the indication information, the access network device determines whether to associate NSAG information for the second network slice.

[0197] Step 603: The first network device obtains the NSAG information associated with the second network slice.

[0198] After receiving the indication information sent by the first network device or the third network device, the access network device that supports the second network slice associates NSAG information for the second network slice and reports the NSAG information associated with the second network slice to the first network device. Optionally, when the access network device receives the indication information sent by the first network device, it can directly send the NSAG information associated with the second network slice to the first network device; when the access network device receives the indication information sent by the third network device, it can send the NSAG information associated with the second network slice to the third network device, and the third network device will send the NSAG information associated with the second network slice to the first network device, or the access network device can also directly send the NSAG information associated with the second network slice to the first network device.

[0199] Exemplarily, the access network device can send the NSAG information associated with the second network slice to the first network device through a RAN configuration update message (RAN configuration update) and an AMF configuration update confirmation message (AMF configuration update ack).

[0200] Optionally, when the first network device determines that the first network slice is unavailable, the first network device can carry the NSAG information associated with the second network slice in the first NSAG information and send it to the terminal device, so that the terminal device can reselect and / or access the cell supporting the second network slice based on the NSAG information associated with the second network slice.

[0201] In the above method, when the first network device determines that the NSAG information associated with the second network slice capable of the first network slice has not been obtained, the first network device sends an indication information to obtain the NSAG information associated with the second network slice, so that the first network device can obtain more comprehensive NSAG information, and thus can provide the NSAG information associated with the second network slice to the terminal device, so as to help the terminal device to reselect and / or access the cell that supports the second network slice, thereby helping to ensure the success rate of the terminal device initiating a slice service request after performing a cell reselection based on the network slice, or helping to ensure the accuracy of the access network device in quickly identifying the terminal device service when the terminal device performs random access based on the network slice.

[0202] An embodiment of the present application also provides a communication method for enabling a first network device to obtain more comprehensive NSAG information, so that when the terminal device performs cell reselection and / or random access, the terminal device can provide the NSAG information associated with the replacement network slice to the terminal device.

[0203] FIG7 is a flow chart of a communication method according to an embodiment of the present application. As shown in the figure, the method may include the following steps:

[0204] Step 701: The first network device obtains the network slices and third NSAG information supported by the access network device.

[0205] The first network device can be the AMF in the 5G communication system, or it can be a network element used for mobility management in a future communication system.

[0206] The first network device can obtain the network slices and third NSAG information supported by the access network device, where the third NSAG information is the NSAG information associated with the network slice by the access network device. For example, after the access network device is online, it can send the network slices it supports and the configured third NSAG information to the first network device through the NG interface, so that the first network device can subsequently instruct the terminal device to replace the unavailable network slice based on the network slices it supports and the third NSAG information.

[0207] Since the current communication protocol allows a network slice not to be associated with any NSAG, the third NSAG information may include the NSAGs associated with one or more network slices among the network slices supported by the access network device, but does not necessarily include the NSAG information associated with each network slice supported by the access network device. For example, the access network device reports that the supported network slices include network slice 1, network slice 2, and network slice 3, and the third NSAG information reported includes the NSAG information associated with network slice 1 and the NSAG information associated with network slice 2. Since the access network device does not configure the associated NSAG information for network slice 3, the third NSAG information reported to the first network device does not include the NSAG information associated with network slice 3.

[0208] Step 702: The first network device sends third NSAG information to the second network device.

[0209] After obtaining the third NSAG information, the first network device can send the obtained third NSAG information to the second network device, so that the second network device can determine which network slice-associated NSAG information needs to be obtained.

[0210] Step 703: The first network device receives second indication information sent by the second network device, where the second indication information includes a slice identifier of the candidate second network slice.

[0211] Among them, the candidate second network slice is a network slice that can be used to replace the first network slice when the first network slice deployed in the core network is unavailable, and the NSAG information associated with the candidate second network slice is not included in the third NSAG information.

[0212] The second network device may estimate network slices that may become unavailable, that is, determine candidate first network slices, and determine network slices that can replace the candidate first network slices. Alternatively, the second network device may not estimate network slices that may become unavailable, but instead use each network slice as a candidate first network slice and determine network slices that can replace the candidate first network slices.

[0213] Among the network slices that can replace the candidate first network slice, the network slice without associated NSAG information can be referred to as a candidate second network slice. The second network device can send second indication information to the first network device, where the second indication information includes a slice identifier of the candidate second network slice to instruct the first network device to obtain the NSAG associated with the candidate second network slice.

[0214] Step 704: The first network device sends third indication information, where the third indication information is used to indicate the NSAG information associated with the candidate second network slice configuration.

[0215] When the first network device sends the third indication information, it can send the third indication information directly to the access network device, or it can send the third indication information to the third network device, so that the third network device indicates that the access network device is the candidate second network slice associated NSAG information, wherein the third network device can be OAM.

[0216] The first network device may first determine the access network device that supports the candidate second network slice, and then send the third indication information to the access network device that supports the candidate second network slice; or, the first network device may not determine the access network device that supports the candidate second network slice, and send the third indication information to multiple access network devices, and the access network device that receives the third indication information shall determine whether it supports the candidate second network slice, and if so, associate the NSAG information with the candidate second network slice.

[0217] Exemplarily, the first network device may send the third indication information to the access network device through an AMF configuration update message (AMF configuration update), an initial context setup request (initial context setup request), etc.

[0218] Similarly, when the first network device sends the third indication information to the third network device, the third network device indicates the access network device to associate the NSAG with the candidate second network slice. This is similar to the way the first network device directly sends the third indication information to the access network device. The third network device can send the indication information to the access network device that supports the candidate second network slice, or it is not necessary to determine the access network device that supports the candidate second network slice. After receiving the indication information, the access network device determines whether to associate the NSAG information with the candidate second network slice.

[0219] Step 705: The first network device obtains the NSAG information associated with the candidate second network slice.

[0220] After receiving the indication information sent by the first network device or the third network device, the access network device that supports the candidate second network slice associates NSAG information for the candidate second network slice and reports the NSAG information associated with the candidate second network slice to the first network device. Optionally, after the access network device receives the indication information sent by the first network device, it can directly send the NSAG information associated with the candidate second network slice to the first network device; after the access network device receives the indication information sent by the third network device, it can send the NSAG information associated with the candidate second network slice to the third network device, and the third network device will send the NSAG information associated with the candidate second network slice to the first network device. Alternatively, the access network device can also directly send the NSAG information associated with the candidate second network slice to the first network device.

[0221] Exemplarily, the access network device can send the NSAG information associated with the candidate second network slice to the first network device through a RAN configuration update message (RAN configuration update) and an AMF configuration update confirmation message (AMF configuration update ack).

[0222] Optionally, after obtaining the NSAG information associated with the candidate second network slice, the first network device may store the NSAG information associated with the candidate second network slice. When the first network device determines that there is an unavailable first network slice, since the first network device has obtained the NSAG information associated with the network slice that can replace the first network slice, the first network device has also obtained the NSAG information associated with the second network slice, and can carry the NSAG information associated with the second network slice in the first NSAG information to the terminal device, so that the terminal device can reselect and / or access the cell that supports the second network slice according to the NSAG information associated with the second network slice.

[0223] In the above method, the first network device determines to obtain the NSAG information associated with the candidate second network slice based on the received second indication information, and then sends the third indication information to obtain the NSAG information associated with the candidate second network slice. After obtaining the NSAG information associated with the candidate second network slice, when the first network slice is unavailable in the subsequent communication process, the NSAG information associated with the second network slice used to replace the first network slice has been obtained by the first network device, thereby facilitating the first network device to send the NSAG information associated with the second network slice to the terminal device, which helps to ensure the success rate of the terminal device initiating a slice service request after performing a cell reselection based on the network slice, or helps to ensure the accuracy of the access network device in quickly identifying the terminal device service when the terminal device performs random access based on the network slice.

[0224] An embodiment of the present application also provides a communication method for enabling a first network device to obtain more comprehensive NSAG information, so that when the terminal device performs cell reselection and / or random access, the terminal device can provide the NSAG information associated with the replacement network slice to the terminal device.

[0225] FIG8 is a flow chart of a communication method according to an embodiment of the present application. As shown in the figure, the method may include the following steps:

[0226] Step 801: The first network device obtains the network slices and third NSAG information supported by the access network device.

[0227] The first network device can be the AMF in the 5G communication system, or it can be a network element used for mobility management in a future communication system.

[0228] The first network device can obtain the network slices and third NSAG information supported by the access network device, where the third NSAG information is the NSAG information associated with the network slice by the access network device. For example, after the access network device is online, it can send the network slices it supports and the configured third NSAG information to the first network device through the NG interface, so that the first network device can subsequently instruct the terminal device to replace the unavailable network slice based on the network slices it supports and the third NSAG information.

[0229] Since the current communication protocol allows a network slice not to be associated with any NSAG, the third NSAG information may include the NSAGs associated with one or more network slices among the network slices supported by the access network device, but does not necessarily include the NSAG information associated with each network slice supported by the access network device. For example, the access network device reports that the supported network slices include network slice 1, network slice 2, and network slice 3, and the third NSAG information reported includes the NSAG information associated with network slice 1 and the NSAG information associated with network slice 2. Since the access network device does not configure the associated NSAG information for network slice 3, the third NSAG information reported to the first network device does not include the NSAG information associated with network slice 3.

[0230] Step 802: The first network device sends the third NSAG information to the second network device.

[0231] After obtaining the third NSAG information, the first network device can send the obtained third NSAG information to the second network device, so that the second network device can determine the second network slice used to replace the first network slice from the network slices associated with the NSAG information.

[0232] Step 803: The first network device obtains the mapping relationship between the first network slice and the second network slice.

[0233] Among them, the first network slice belongs to the network slice allowed by the terminal device, the second network slice is the network slice that replaces the first network slice to provide services for the terminal device, and the NSAG information associated with the second network slice is included in the third NSAG information.

[0234] When the second network device detects that the first network slice allowed by the terminal device is unavailable, the second network slice is determined from the network slices associated with the NSAG information based on the obtained third NSAG information to replace the first network slice. Therefore, the NSAG information associated with the second network slice used to replace the first network slice is determined and made available for acquisition by the first network device. The first network device can then provide the NSAG information associated with the second network slice to the terminal device without having to instruct the access network device to associate NSAG information for the second network slice.

[0235] Optionally, the first network device can carry the NSAG information associated with the second network slice in the first NSAG information and send it to the terminal device, so that the terminal device can reselect and / or access the cell supporting the second network slice based on the NSAG information associated with the second network slice.

[0236] In the above method, the first network device sends the acquired third NSAG information to the second network device. When the second network device determines that the first network slice allowed by the terminal device is unavailable, the second network device determines the second network slice to replace the first network slice from the network slices that are already associated with the NSAG information, so that the first network device no longer needs to instruct the access network device to associate NSAG information for the second network slice, and can provide the terminal device with the NSAG information associated with the second network slice, so that the terminal device can reselect and / or access the cell that supports the second network slice, which helps to ensure the success rate of the terminal device initiating a slice service request after performing a cell reselection based on the network slice, or helps to ensure the accuracy of the access network device in quickly identifying the terminal device service when the terminal device performs random access based on the network slice.

[0237] An embodiment of the present application also provides a communication method for preventing a terminal device from reselecting and / or accessing a cell that only supports unavailable network slices when performing cell reselection to obtain random access, thereby helping to improve the success rate of the terminal device initiating a slice service request after performing cell reselection based on network slicing, or helping to improve the accuracy of the access network device's rapid identification of terminal device services when the terminal device performs random access based on network slicing.

[0238] FIG9 is a flow chart of a communication method according to an embodiment of the present application. As shown in the figure, the method may include the following steps:

[0239] Step 901: The terminal device obtains the mapping relationship between the first network slice and the second network slice and the first NSAG information.

[0240] Among them, the first network slice belongs to the network slice allowed by the terminal device. When the terminal device receives the mapping relationship between the first network slice and the second network slice, it means that the first network slice deployed in the core network is currently unavailable, so the first network slice is replaced by the second network slice. When the terminal device has business needs, the second network slice can provide business services to the terminal device.

[0241] The first NSAG information may include NSAG information associated with the network slice configured by the access network device. When the terminal device wants to reselect and / or access a cell that supports a certain network slice, it can perform cell reselection and / or random access based on the NSAG information associated with the network slice.

[0242] The mapping relationship between the first network slice and the second network, and the first NSAG information can be sent by the first network device to the terminal device. Specifically, the first network device can send the above-mentioned mapping relationship and the first NSAG information to the terminal device through a NAS message. The mapping relationship and the first NSAG information can be sent to the terminal device through the same message, or they can be sent to the terminal device separately through different messages. When sent to the terminal device separately through different messages, the embodiment of the present application does not limit the order of sending the mapping relationship and sending the first NSAG. Among them, the first network device can be the AMF in the 5G communication system, or it can also be a network element used for mobility management in a future communication system.

[0243] Step 902: The terminal device determines the second NSAG information based on the above mapping relationship and the first NSAG information, wherein the second NSAG information does not include the NSAG information associated with the first network slice.

[0244] Based on the above mapping relationship, the terminal device can determine that the first network slice deployed in the core network is currently unavailable and the second network slice can replace the first network slice to provide services for the terminal device. In this case, the terminal device should not reselect and / or access a cell that only supports the first network slice. Therefore, if the first NSAG information includes the NSAG information associated with the first network slice, the terminal device can remove the NSAG information associated with the first network slice from the first NSAG information to obtain the second NSAG information.

[0245] Step 903: The terminal device performs cell reselection and / or random access according to the second NSAG information.

[0246] When the terminal device performs cell reselection and / or random access based on the second NSAG information, since the second NSAG information no longer contains the NSAG information associated with the first network slice, the terminal device will not reselect and / or access the cell that only supports the first network slice, thereby avoiding the terminal device being unable to obtain service data.

[0247] When performing cell reselection and / or random access, the terminal device may first determine one or more network slices (hereinafter referred to as one or more network slices) for cell reselection and / or random access, and then perform cell reselection and / or random access based on the one or more network slices and the second NSAG information. Since the second NSAG information does not contain the NSAG information associated with the first network slice, even if the one or more network slices include the first network slice, the terminal device will not reselect and / or access a cell that only supports the first network slice.

[0248] There are multiple ways for the terminal device to determine the second NSAG information, which are introduced below respectively.

[0249] Determination method 1: The non-access layer of the terminal device sends a first network slice identifier list and a first NSAG information to the access layer of the terminal device based on the above-mentioned mapping relationship and the slice identifiers of one or more network slices used for cell reselection and / or random access; the access layer of the terminal device determines the second NSAG information based on the first network slice identifier list and the first NSAG information.

[0250] The first network slice identifier list includes identifiers corresponding to the network slices other than the first network slice in the one or more network slices. In other words, the non-access layer of the terminal device determines, based on the mapping relationship, that the first network slice is unavailable and should exclude the first network slice from the one or more network slices used for cell reselection and / or random access, thereby obtaining the first network slice identifier list.

[0251] After obtaining the first network slice identifier list and the first NSAG information, the access layer of the terminal device determines the second NSAG information. Specifically, after obtaining the first network slice identifier list, the access layer of the terminal device determines that the first network slice identifier is not included in the first network slice identifier list, so the NSAG information associated with the first network slice in the first NSAG information is removed to obtain the second NSAG information.

[0252] Similarly, if the first network slice identifier list does not include the third network slice identifier, and the first NSAG information includes the NSAG information associated with the third network slice, then the access layer of the terminal device can also remove the NSAG information associated with the third network slice in the first NSAG information, and then the obtained second NSAG information includes neither the NSAG information associated with the second network slice nor the NSAG information associated with the third network slice. The third network slice is any one of the network slices allowed by the terminal device (allowed NSSAI), partially allowed network slice (partially Allowed NSSAI) or requested network slice (requested NSSAI).

[0253] In a specific embodiment, the flow chart of the above communication method may be shown in FIG10 , which includes the following steps:

[0254] Step 1001. The AMF sends the mapping relationship between the first network slice and the second network slice and the first NSAG information to the non-access stratum (NAS) of the UE through a NAS message.

[0255] Optionally, AMF may execute the above step 1001 after receiving the mapping relationship between the first network slice and the second network slice sent by PCF / NSSF / OAM.

[0256] Step 1002: UE NAS determines a first network slice identifier list based on the above mapping relationship and the slice identifiers of one or more network slices used for cell reselection and / or random access.

[0257] The first network slice identifier list includes identifiers corresponding to network slices other than the first network slice in the one or more network slices. In other words, the UE NAS removes the first network slice from the one or more network slices used for cell reselection and / or random access, thereby obtaining the first network slice identifier list.

[0258] Optionally, the UE NAS may execute the above step 1002 when the UE needs to perform cell reselection and / or random access; or, the UE NAS may also execute the above step 1002 immediately after receiving the mapping relationship between the first network slice and the second network slice and the first NSAG information sent by the AMF.

[0259] Step 1003: UE NAS sends the first network slice identifier list and the first NSAG information to the UE's access layer (AS).

[0260] If the UE NAS executes the above step 1002 when the UE needs to perform cell reselection and / or random access, then the UE NAS can immediately execute the above step 1003 after executing the above step 1002; if the UE NAS executes the above step 1002 immediately after receiving the mapping relationship between the first network slice and the second network slice and the first NSAG information, then the UE NAS can wait until the UE needs to perform cell reselection and / or random access before executing the above step 1003.

[0261] Step 1004: UE AS determines the second NSAG information based on the first network slice identifier list and the first NSAG information.

[0262] After obtaining the first network slice identifier list, UE AS determines that the first network slice identifier is not included in the first network slice identifier list, so it removes the NSAG information associated with the first network slice in the first NSAG information to obtain the second NSAG information.

[0263] Step 1005: The UE AS performs cell reselection and / or random access according to the second NSAG information.

[0264] Determination method 2: The non-access layer of the terminal device sends the above-mentioned mapping relationship, the first NSAG information and the slice identifier of one or more network slices used for cell reselection and / or random access to the access layer of the terminal device; the access layer of the terminal device determines the first network slice identifier list based on the mapping relationship and the slice identifier of one or more network slices used for cell reselection and / or random access, and the access layer of the terminal device determines the second NSAG information based on the first network slice identifier list and the first NSAG information.

[0265] The first network slice identifier list includes identifiers corresponding to network slices other than the first network slice in the one or more network slices. In other words, the access layer of the terminal device determines, based on the mapping relationship, that the first network slice is unavailable and should exclude the first network slice from the one or more network slices used for cell reselection and / or random access, thereby obtaining the first network slice identifier list.

[0266] After determining the first network slice identifier list, the access layer of the terminal device determines the second NSAG information based on the first network slice identifier list and the first NSAG information. Specifically, after obtaining the first network slice identifier list, the access layer of the terminal device determines that the first network slice identifier is not included in the first network slice identifier list, so the NSAG information associated with the first network slice in the first NSAG information is removed to obtain the second NSAG information.

[0267] Similarly, if the first network slice identifier list does not include the third network slice identifier, and the first NSAG information includes the NSAG information associated with the third network slice, then the access layer of the terminal device can also remove the NSAG information associated with the third network slice in the first NSAG information, and then the obtained second NSAG information includes neither the NSAG information associated with the second network slice nor the NSAG information associated with the third network slice. The third network slice is any one of the network slices allowed by the terminal device (allowed NSSAI), partially allowed network slice (partially Allowed NSSAI) or requested network slice (requested NSSAI).

[0268] In a specific embodiment, the flow chart of the above communication method may be shown in FIG11 , which includes the following steps:

[0269] Step 1101. AMF sends the mapping relationship between the first network slice and the second network slice and the first NSAG information to the UE NAS through a NAS message.

[0270] Optionally, AMF may execute the above step 1101 after receiving the mapping relationship between the first network slice and the second network slice sent by PCF / NSSF / OAM.

[0271] Step 1102: UE NAS sends the above mapping relationship, the first NSAG information, and the slice identifiers of one or more network slices used for cell reselection and / or random access to the UE AS.

[0272] Optionally, the UE NAS may execute the above step 1102 when the UE needs to perform cell reselection and / or random access; alternatively, the UE NAS may also execute the above step 1102 immediately after receiving the mapping relationship between the first network slice and the second network slice and the first NSAG information sent by the AMF.

[0273] Step 1103: UE AS determines a first network slice identifier list based on the above mapping relationship and the slice identifiers of one or more network slices used for cell reselection and / or random access.

[0274] The first network slice identifier list includes identifiers corresponding to the network slices other than the first network slice in the one or more network slices. That is, the UE AS removes the first network slice from the one or more network slices used for cell reselection and / or random access, thereby obtaining the first network slice identifier list.

[0275] Step 1104: UE AS determines the second NSAG information based on the first network slice identifier list and the first NSAG information.

[0276] After obtaining the first network slice identifier list, UE AS determines that the first network slice identifier is not included in the first network slice identifier list, so it removes the NSAG information associated with the first network slice in the first NSAG information to obtain the second NSAG information.

[0277] Step 1105: The UE AS performs cell reselection and / or random access according to the second NSAG information.

[0278] Determination method 3: The above step of determining the second NSAG information can be specifically performed by the non-access layer of the terminal device.

[0279] The non-access layer of the terminal device can determine the second NSAG information based on the above-mentioned mapping relationship and the first NSAG information, and then send the second NSAG information and the slice identifier of one or more network slices used for cell reselection and / or random access to the access layer of the terminal device; the access layer of the terminal device performs cell reselection and / or random access based on the second NSAG information and the slice identifier of the above-mentioned one or more network slices.

[0280] Specifically, the non-access layer of the terminal device can determine that the first network slice is unavailable based on the above-mentioned mapping relationship, and the NSAG information associated with the first network slice should be removed. Therefore, the non-access layer of the terminal device removes the NSAG information associated with the first network slice from the first NSAG information, obtains the second NSAG information, and sends the second NSAG information and the slice identifiers of one or more network slices to the access layer of the terminal device.

[0281] In a specific example, the non-access layer of the terminal device can first determine the first network slice identifier list based on the above-mentioned mapping relationship, wherein the first network slice identifier list includes identifiers corresponding to the network slices other than the first network slice in the above-mentioned one or more network slices. That is, the non-access layer of the terminal device determines, based on the mapping relationship, that the first network slice is unavailable, and the first network slice should be removed from the one or more network slices used for cell reselection and / or random access, thereby obtaining the first network slice identifier list. Then, the non-access layer of the terminal device determines the second NSAG information based on the first network slice identifier list and the first NSAG information. After obtaining the first network slice identifier list, the non-access layer of the terminal device determines that the first network slice identifier is not included in the first network slice identifier list, so the NSAG information associated with the first network slice in the first NSAG information is removed to obtain the second NSAG information.

[0282] Optionally, the slice identifier of one or more network slices sent by the non-access layer of the terminal device to the access layer of the terminal device for cell reselection and / or random access may also be the slice identifier after removing the slice identifier of the first network slice.

[0283] Since the second NSAG information obtained by the access layer of the terminal device does not include the NSAG information associated with the first network slice, even if the above one or more network slices include the first network slice, the access layer of the terminal device will not reselect and / or access the cell that only supports the first network slice.

[0284] In the above-mentioned determination method 2 and determination method 3, the non-access stratum of the terminal device needs to send the slice identifiers of one or more network slices used for cell reselection and / or random access to the access stratum of the terminal device. Optionally, when the first NSAG information acquired by the terminal device does not include the NSAG information associated with the second network slice, the slice identifiers of one or more network slices used for cell reselection and / or random access sent by the non-access stratum of the terminal device to the terminal device may not include the slice identifier of the second network slice.

[0285] In a specific embodiment, the flow chart of the above communication method may be shown in FIG12 , which includes the following steps:

[0286] Step 1201: AMF sends the mapping relationship between the first network slice and the second network slice and the first NSAG information to the UE NAS through a NAS message.

[0287] Optionally, AMF may execute the above step 1201 after receiving the mapping relationship between the first network slice and the second network slice sent by PCF / NSSF / OAM.

[0288] Step 1202: UE NAS determines a first network slice identifier list based on the above mapping relationship and the slice identifiers of one or more network slices used for cell reselection and / or random access.

[0289] The first network slice identifier list includes identifiers corresponding to network slices other than the first network slice in the one or more network slices. In other words, the UE NAS removes the first network slice from the one or more network slices used for cell reselection and / or random access, thereby obtaining the first network slice identifier list.

[0290] Step 1203: UE NAS determines the second NSAG information based on the first network slice identifier list and the first NSAG information.

[0291] After obtaining the first network slice identifier list, UE NAS determines that the first network slice identifier is not included in the first network slice identifier list, so the NSAG information associated with the first network slice in the first NSAG information is removed to obtain the second NSAG information.

[0292] Optionally, the UE NAS may execute the above steps 1202 and 1203 when the UE needs to perform cell reselection and / or random access, or may execute the above steps 1202 and 1203 immediately after receiving the mapping relationship between the first network slice and the second network slice and the first NSAG information sent by the AMF.

[0293] Step 1204: UE NAS sends the second NSAG information and the slice identifiers of one or more network slices used for cell reselection and / or random access to the UE AS.

[0294] If the UE NAS executes steps 1202 and 1203 when the UE needs to perform cell reselection and / or random access, then the UE NAS may immediately execute step 1204 after executing step 1203. If the UE NAS executes steps 1202 and 1203 immediately after receiving the mapping relationship between the first network slice and the second network slice and the first NSAG information, then the UE NAS may wait until the UE needs to perform cell reselection and / or random access before executing step 1204. Alternatively, steps 1202 to 1204 may be executed immediately after the UE receives the mapping relationship and the first NSAG information sent by the AMF, and step 1205 may be executed when the UE needs to perform cell reselection and / or random access.

[0295] Step 1205: The UE AS performs cell reselection and / or random access according to the second NSAG information.

[0296] Figure 13 is a schematic diagram of a communication device provided according to an embodiment of the present application. The communication device includes a processing module 1301 and a transceiver module 1302. The processing module 1301 is used to implement data processing by the communication device. The transceiver module 1302 is used to receive content from the communication device to other units or network elements, or to send content from the communication device to other units or network elements. It should be understood that the processing module 1301 in the embodiment of the present application can be implemented by a processor or a processor-related circuit component (or, referred to as a processing circuit), and the transceiver module 1302 can be implemented by a receiver / transmitter or a receiver / transmitter-related circuit component.

[0297] Exemplarily, the communication device may be a communication device, or may be a chip used in the communication device, or other combined devices, components, etc. having the functions of the above-mentioned communication device.

[0298] When the communication device is a first network device, the processing module 1301 determines that the first network slice is unavailable, and the first network slice belongs to the network slice allowed by the terminal device; the mapping relationship between the first network slice and the second network slice and the first NSAG information are sent to the terminal device through the transceiver module 1302, and the second network slice is a network slice that replaces the first network slice to provide services for the terminal device, and the first NSAG information does not include the NSAG information associated with the first network slice.

[0299] In addition, the above modules can also be used to support other processes executed by the first network device in the embodiments shown in Figures 2 to 5. The beneficial effects can be referred to the above description and will not be repeated here.

[0300] When the communication device is a first network device, the processing module 1301 obtains the network slices and third NSAG information supported by the access network device; sends the first indication information through the transceiver module 1302, and the first indication information is used to indicate the NSAG information associated with the second network slice configuration, the second network slice is a network slice that replaces the first network slice to provide services for the terminal device, the first network slice belongs to the network slice allowed by the terminal device, and the third NSAG information does not include the NSAG information associated with the second network slice; obtains the NSAG information associated with the second network slice through the transceiver module 1302.

[0301] In addition, the above modules can also be used to support other processes executed by the first network device in the embodiment shown in Figure 6. The beneficial effects can be referred to the above description and will not be repeated here.

[0302] When the communication device is a first network device, the processing module 1301 obtains the network slices and third NSAG information supported by the access network device; sends the third NSAG information through the transceiver module 1302; receives second indication information through the transceiver module 1302, the second indication information including the slice identifier of the candidate second network slice, the candidate second network slice being a network slice that can be used to replace the first network slice when the first network slice is unavailable, and the NSAG information associated with the candidate second network slice is not included in the third NSAG information; sends third indication information through the transceiver module 1302 in response to the second indication information, the third indication information being used to indicate the configuration of associated NSAG information for the candidate second network slice; obtains the NSAG information associated with the candidate second network slice.

[0303] In addition, the above modules can also be used to support other processes executed by the first network device in the embodiment shown in Figure 7. The beneficial effects can be referred to the above description and will not be repeated here.

[0304] When the communication device is a first network device, the processing module 1301 obtains the network slices and third NSAG information supported by the access network device; sends the third NSAG information through the transceiver module 1302; obtains the mapping relationship between the first network slice and the second network slice through the transceiver module 1302, the NSAG information associated with the second network slice is included in the third NSAG information, the first network slice belongs to the network slice allowed by the terminal device, and the second network slice is a network slice that replaces the first network slice to provide services for the terminal device.

[0305] In addition, the above modules can also be used to support other processes executed by the first network device in the embodiment shown in Figure 8. The beneficial effects can be referred to the above description and will not be repeated here.

[0306] When the communication device is a second network device, the processing module 1301 obtains third NSAG information through the transceiver module 1302, and the third NSAG information includes the NSAG information associated with the configuration of one or more network slices supported by the access network device; determines a candidate second network slice of the first network slice, and the candidate second network slice is a network slice that can be used to replace the first network slice when the first network slice is unavailable, and the third NSAG information does not include the NSAG information associated with the candidate second network slice; sends second indication information through the transceiver module 1302, and the second indication information includes the identifier of the candidate second network slice, which is used to indicate the acquisition of NSAG information associated with the candidate second network slice.

[0307] In addition, the above modules can also be used to support other processes executed by the second network device in the embodiment shown in Figure 7. The beneficial effects can be referred to the above description and will not be repeated here.

[0308] When the communication device is a second network device, the processing module 1301 obtains the third NSAG information through the transceiver module 1302, and the third NSAG information includes the NSAG information associated with the configuration of one or more network slices supported by the access network device; when the first network slice is unavailable, the second network slice is determined, the first network slice belongs to the network slice allowed by the terminal device, the second network slice is the network slice that replaces the first network slice to provide services for the terminal device, and the third NSAG information includes the NSAG information associated with the second network slice; the mapping relationship between the first network slice and the second network slice is sent through the transceiver module 1302.

[0309] In addition, the above modules can also be used to support other processes executed by the second network device in the embodiment shown in Figure 8. The beneficial effects can be referred to the above description and will not be repeated here.

[0310] When the communication device is an access network device, the processing module 1301 receives the first indication information through the transceiver module 1302, where the first indication information includes a slice identifier of the second network slice, and the first indication information is used to indicate the configuration of associated NSAG information for the second network slice; configure the NSAG information associated with the second network slice; and send the NSAG information associated with the second network slice through the transceiver module 1302.

[0311] In addition, the above modules can also be used to support other processes executed by the access network devices in the embodiments shown in Figures 2 to 7. The beneficial effects can be referred to the above description and will not be repeated here.

[0312] When the communication device is a terminal device, the processing module 1301 obtains the mapping relationship between the first network slice and the second network slice and the NSAG information of the first network slice access layer group through the transceiver module 1302, the first network slice belongs to the network slice allowed by the terminal device, the second network slice is a network slice that replaces the first network slice to provide services for the terminal device, the first NSAG information is the NSAG information associated with the network slice configured for the terminal device, and the first NSAG information includes the NSAG information associated with the first network slice; the second NSAG information is determined according to the mapping relationship and the first NSAG information, and the second NSAG information does not include the NSAG information associated with the first network slice; and cell reselection and / or random access is performed according to the second NSAG information.

[0313] In addition, the above modules can also be used to support other processes executed by the terminal device in the embodiments shown in Figures 9 to 12. The beneficial effects can be referred to the previous description and will not be repeated here.

[0314] Figure 14 is a schematic diagram of another communication device provided according to an embodiment of the present application, which includes: a processor 1401, a communication interface 1402, and further includes a memory 1403 and a bus 1404. The processor 1401, the communication interface 1402 and the memory 1403 can be interconnected through a bus 1404; the bus 1404 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The above-mentioned bus 1404 can be divided into an address bus, a data bus and a control bus, etc. For ease of representation, only one line is used in Figure 14, but it does not mean that there is only one bus or one type of bus.

[0315] Processor 1401 may be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and an NP. The processor may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof. Memory 1403 may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. Volatile memory can be random access memory (RAM), which acts as external cache memory.

[0316] The processor 1401 is used to implement data processing operations of the communication device, and the communication interface 1402 is used to implement receiving operations and sending operations of the communication device.

[0317] When the communication device is a first network device, the processor 1401 determines that the first network slice is unavailable, and the first network slice belongs to the network slice allowed by the terminal device; the mapping relationship between the first network slice and the second network slice and the first NSAG information are sent to the terminal device through the communication interface 1402, and the second network slice is a network slice that replaces the first network slice to provide services for the terminal device, and the first NSAG information does not include the NSAG information associated with the first network slice.

[0318] In addition, the above components can also be used to support other processes executed by the first network device in the embodiments shown in Figures 2 to 5. The beneficial effects can be referred to the previous description and will not be repeated here.

[0319] When the communication device is a first network device, the processor 1401 obtains the network slices and third NSAG information supported by the access network device; sends a first indication message through the communication interface 1402, and the first indication information is used to indicate the NSAG information associated with the second network slice configuration, the second network slice is a network slice that replaces the first network slice to provide services for the terminal device, the first network slice belongs to the network slice allowed by the terminal device, and the third NSAG information does not include the NSAG information associated with the second network slice; obtains the NSAG information associated with the second network slice through the communication interface 1402.

[0320] In addition, the above components can also be used to support other processes executed by the first network device in the embodiment shown in Figure 6. The beneficial effects can be referred to the previous description and will not be repeated here.

[0321] When the communication device is a first network device, the processor 1401 obtains the network slices and third NSAG information supported by the access network device; sends the third NSAG information through the communication interface 1402; receives second indication information through the communication interface 1402, the second indication information including the slice identifier of the candidate second network slice, the candidate second network slice being a network slice that can be used to replace the first network slice when the first network slice is unavailable, and the NSAG information associated with the candidate second network slice is not included in the third NSAG information; sends third indication information through the communication interface 1402 in response to the second indication information, the third indication information being used to indicate the configuration of associated NSAG information for the candidate second network slice; obtains the NSAG information associated with the candidate second network slice.

[0322] In addition, the above components can also be used to support other processes executed by the first network device in the embodiment shown in Figure 7. The beneficial effects can be referred to the previous description and will not be repeated here.

[0323] When the communication device is a first network device, the processor 1401 obtains the network slices and third NSAG information supported by the access network device; sends the third NSAG information through the communication interface 1402; obtains the mapping relationship between the first network slice and the second network slice through the communication interface 1402, the NSAG information associated with the second network slice is included in the third NSAG information, the first network slice belongs to the network slice allowed by the terminal device, and the second network slice is a network slice that replaces the first network slice to provide services for the terminal device.

[0324] In addition, the above components can also be used to support other processes executed by the first network device in the embodiment shown in Figure 8. The beneficial effects can be referred to the previous description and will not be repeated here.

[0325] When the communication device is a second network device, the processor 1401 obtains third NSAG information through the communication interface 1402, and the third NSAG information includes NSAG information associated with the configuration of one or more network slices supported by the access network device; determines a candidate second network slice of the first network slice, and the candidate second network slice is a network slice that can be used to replace the first network slice when the first network slice is unavailable, and the third NSAG information does not include NSAG information associated with the candidate second network slice; sends second indication information through the communication interface 1402, and the second indication information includes an identifier of the candidate second network slice, which is used to indicate the acquisition of NSAG information associated with the candidate second network slice.

[0326] In addition, the above components can also be used to support other processes executed by the second network device in the embodiment shown in Figure 7. The beneficial effects can be referred to the previous description and will not be repeated here.

[0327] When the communication device is a second network device, the processor 1401 obtains third NSAG information through the communication interface 1402, and the third NSAG information includes NSAG information associated with the configuration of one or more network slices supported by the access network device; when the first network slice is unavailable, the second network slice is determined, the first network slice belongs to the network slice allowed by the terminal device, and the second network slice is a network slice that replaces the first network slice to provide services for the terminal device, and the third NSAG information includes NSAG information associated with the second network slice; the mapping relationship between the first network slice and the second network slice is sent through the communication interface 1402.

[0328] In addition, the above components can also be used to support other processes executed by the second network device in the embodiment shown in Figure 8. The beneficial effects can be referred to the previous description and will not be repeated here.

[0329] When the communication device is an access network device, the processor 1401 receives first indication information through the communication interface 1402, where the first indication information includes a slice identifier of a second network slice, and the first indication information is used to indicate the configuration of associated NSAG information for the second network slice; configure the NSAG information associated with the second network slice; and send the NSAG information associated with the second network slice through the communication interface 1402.

[0330] In addition, the above components can also be used to support other processes executed by the access network equipment in the embodiments shown in Figures 2 to 7. The beneficial effects can be referred to the previous description and will not be repeated here.

[0331] When the communication device is a terminal device, the processor 1401 obtains the mapping relationship between the first network slice and the second network slice and the NSAG information of the first network slice access layer group through the communication interface 1402, the first network slice belongs to the network slice allowed by the terminal device, the second network slice is a network slice that replaces the first network slice to provide services for the terminal device, the first NSAG information is NSAG information associated with the network slice configured for the terminal device, and the first NSAG information includes NSAG information associated with the first network slice; the second NSAG information is determined according to the mapping relationship and the first NSAG information, and the second NSAG information does not include the NSAG information associated with the first network slice; and cell reselection and / or random access is performed according to the second NSAG information.

[0332] In addition, the above components can also be used to support other processes executed by the terminal device in the embodiments shown in Figures 9 to 12. The beneficial effects can be referred to the previous description and will not be repeated here.

[0333] Based on the same technical concept, an embodiment of the present application also provides a computer-readable storage medium, in which computer-readable instructions are stored. When the computer-readable instructions are executed on a computer, the method described in any possible implementation method described above is executed.

[0334] An embodiment of the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the above method embodiment to be executed.

[0335] An embodiment of the present application provides a chip, including: a processor, the processor is coupled to a memory, the memory is used to store instructions, and when the instructions are executed by the processor, the chip implements the method steps executed by any of the above nodes.

[0336] An embodiment of the present application provides a communication system, which includes the first network device and the second network device described above, and further includes an access network device and / or a terminal device.

[0337] In the description of the embodiments of this application, "and / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone. The term "plurality" used in this application refers to two or more.

[0338] In addition, it should be understood that, in the description of the present application, words such as "first" and "second" are only used for the purpose of distinguishing the description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order. References to "one embodiment" or "some embodiments" described in this specification mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0339] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in a random access memory, a flash memory, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, a register, a hard disk, a mobile hard disk, a CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in a base station or a terminal. Of course, the processor and the storage medium can also exist in a base station or a terminal as discrete components.

[0340] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0341] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0342] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

Claims

1. A communication method, characterized in that: Applied to a first network device, the method comprises: Determining that a first network slice is unavailable, the first network slice being a network slice allowed by the terminal device; The mapping relationship between the first network slice and the second network slice and the first NSAG information are sent to the terminal device, where the second network slice is a network slice that replaces the first network slice to provide services for the terminal device, and the first NSAG information does not include the NSAG information associated with the first network slice.

2. The method according to claim 1, characterized in that The method further comprises: When the first network slice becomes available again, second NSAG information is sent to the terminal device, where the second NSAG information includes NSAG information associated with the first network slice.

3. The method according to claim 1 or 2, characterized in that: The determining that the first network slice is unavailable includes: Receive a mapping relationship between the first network slice and the second network slice, where the mapping relationship is sent when it is determined that the first network slice is unavailable.

4. The method according to any one of claims 1 to 3, characterized in that: The method further comprises: Get the network slices and third NSAG information supported by the access network device.

5. The method according to claim 4, characterized in that The third NSAG information does not include NSAG information associated with the second network slice; After acquiring the network slices and the third NSAG information supported by the access network device, the method further includes: Sending first indication information, where the first indication information is used to indicate NSAG information associated with the second network slice configuration; Obtain the NSAG information associated with the second network slice.

6. The method according to claim 5, characterized in that Before sending the first indication information, the method further includes: Determine an access network device that supports the second network slice.

7. The method according to claim 5 or 6, characterized in that: The first NSAG information includes NSAG information associated with the second network slice.

8. The method according to claim 4, characterized in that After acquiring the network slices and the third NSAG information supported by the access network device, the method further includes: Sending the third NSAG information; receiving second indication information, where the second indication information is used to indicate a slice identifier of a candidate second network slice, where the candidate second network slice is a network slice that can be used to replace the first network slice when the first network slice is unavailable, and the NSAG information associated with the candidate second network slice is not included in the third NSAG information; sending third indication information in response to the second indication information, wherein the third indication information is used to indicate NSAG information associated with the candidate second network slice configuration; Obtain the NSAG information associated with the candidate second network slice.

9. The method according to claim 8, characterized in that Before sending third indication information in response to the second indication information, the method further includes: Determine an access network device that supports the candidate second network slice.

10. The method according to claim 8 or 9, characterized in that: The first NSAG information includes NSAG information associated with the candidate second network slice.

11. The method according to claim 4, characterized in that The NSAG information associated with the second network slice is included in the third NSAG information.

12. A communication method, characterized in that: Applied to a first network device, the method comprises: Obtain the network slices and third NSAG information supported by the access network device; Sending first indication information, where the first indication information is used to indicate NSAG information associated with the configuration of a second network slice, where the second network slice is a network slice that replaces the first network slice to provide services for the terminal device, the first network slice belongs to a network slice allowed by the terminal device, and the third NSAG information does not include NSAG information associated with the second network slice; Obtain the NSAG information associated with the second network slice.

13. The method according to claim 12, characterized in that Before sending the first indication information, the method further includes: Determine an access network device that supports the second network slice.

14. The method according to claim 12 or 13, characterized in that The method further comprises: Send the NSAG information associated with the second network slice to the terminal device.

15. A communication method, characterized in that: Applied to a first network device, the method comprises: Obtain the network slices and third NSAG information supported by the access network device; Sending the third NSAG information; receiving second indication information, where the second indication information includes a slice identifier of a candidate second network slice, where the candidate second network slice is a network slice that can be used to replace the first network slice when the first network slice is unavailable, and the NSAG information associated with the candidate second network slice is not included in the third NSAG information; sending third indication information in response to the second indication information, wherein the third indication information is used to indicate NSAG information associated with the candidate second network slice configuration; Obtain the NSAG information associated with the candidate second network slice.

16. The method according to claim 15, characterized in that Before sending third indication information in response to the second indication information, the method further includes: Determine an access network device that supports the candidate second network slice.

17. The method according to claim 15 or 16, characterized in that The method further comprises: The NSAG information associated with the second network slice is sent to the terminal device, and the second network slice belongs to the candidate second network slice.

18. A communication method, characterized in that: Applied to a first network device, the method comprises: Obtain the network slices and third NSAG information supported by the access network device; Sending the third NSAG information; Obtain a mapping relationship between the first network slice and the second network slice, the NSAG information associated with the second network slice is included in the third NSAG information, the first network slice belongs to the network slice allowed by the terminal device, and the second network slice is a network slice that replaces the first network slice to provide services for the terminal device.

19. A communication method, characterized in that: Applied to a terminal device, the method comprises: Obtain a mapping relationship between a first network slice and a second network slice and NSAG information of a first network slice access layer group, wherein the first network slice belongs to a network slice allowed by the terminal device, and the second network slice is a network slice that replaces the first network slice to provide services for the terminal device, and the first NSAG information is NSAG information associated with a network slice configured for the terminal device, and the first NSAG information includes NSAG information associated with the first network slice; Determine second NSAG information according to the mapping relationship and the first NSAG information, where the second NSAG information does not include NSAG information associated with the first network slice; Perform cell reselection and / or random access according to the second NSAG information.

20. The method according to claim 19, characterized in that The determining the second NSAG information according to the mapping relationship and the first NSAG information includes: The non-access layer of the terminal device sends a first network slice identifier list and the first NSAG information to the access layer of the terminal device according to the mapping relationship and one or more network slices for cell reselection and / or random access, where the first network slice identifier list includes identifiers of network slices other than the first network slice in the one or more network slices; The access layer of the terminal device determines the second NSAG information based on the first NSAG information and the first network slice identifier list.

21. The method according to claim 19, characterized in that The determining the second NSAG information according to the mapping relationship and the first NSAG information includes: The non-access layer of the terminal device determines the second NSAG information according to the mapping relationship and the first NSAG information; The non-access layer of the terminal device sends the second NSAG information and slice identifiers of one or more network slices used for cell reselection and / or random access to the access layer of the terminal device.

22. The method according to claim 21, characterized in that The non-access layer of the terminal device determines the second NSAG information according to the mapping relationship and the first NSAG information, including: The non-access layer of the terminal device determines a first network slice identifier list according to the mapping relationship, where the first network slice identifier list includes identifiers of network slices other than the first network slice in the one or more network slices; The non-access layer of the terminal device determines the second NSAG information based on the first network slice identifier list and the first NSAG information.

23. The method according to claim 21, characterized in that The slice identifiers of the one or more network slices do not include the slice identifier of the first network slice.

24. The method according to any one of claims 21 to 23, characterized in that: When the first NSAG information does not include NSAG information associated with the second network slice, the one or more network slices do not include the second network slice.

25. The method according to claim 19, characterized in that The determining the second NSAG information according to the mapping relationship and the first NSAG information includes: The non-access layer of the terminal device sends the mapping relationship, the first NSAG information, and the slice identifiers of one or more network slices for cell reselection and / or random access to the access layer of the terminal device; The access layer of the terminal device determines a first network slice identifier list according to the mapping relationship, where the first network slice identifier list includes identifiers of network slices other than the first network slice in the one or more network slices; The access layer of the terminal device determines the second NSAG information based on the first network slice identifier list and the first NSAG information.

26. A communication device, characterized in that: include: A processing module and a communication module, wherein the processing module is used to send and receive messages through the communication module to execute the method as described in any one of claims 1-25.

27. A communication device, characterized in that: include: A processor, wherein the processor is coupled to a memory, wherein the memory is used to store a program or an instruction, and when the program or the instruction is executed by the processor, the device executes the method according to any one of claims 1 to 25.

28. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed on a computer, the computer is enabled to execute the method according to any one of claims 1 to 25.

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