WO2025067375A1 - Communication method and apparatus - Google Patents

Abstract

Provided in the embodiments of the present application are a communication method and apparatus. The method comprises: a first device receiving a switching request from a second device, wherein the switching request is used for requesting the switching of a first session to the first device, a network slice associated with the first session is a first network slice, and the first session is used for providing to a terminal device a service corresponding to a second network slice; and when a network slice list supported by a cell managed by the first device does not comprise an identifier of the second network slice, the second device sending first information to the first device, wherein the first information is used for indicating that a processing mode for the first session is rejected access or deactivation. By using the method, when a network slice associated with a first session is different from a network slice that actually provides a service to the first session, the first device can perform access control on the basis of the network slice that actually provides the service, thereby improving the accuracy of session switching, and improving the communication efficiency.

Description

A communication method and device

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on September 27, 2023, with application number 202311282891.X and application name "A Communication Method and Device", all contents of which are incorporated by reference in this application.

Technical Field

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

Background Art

In order to make the communication network flexible and scalable while meeting different business needs, the fifth generation (5G) mobile communication system proposes to provide users with customized network services through end-to-end network slicing (hereinafter referred to as slicing). A slice can be regarded as a logical subnet, and each slice is isolated from each other, so that targeted services can be provided to users. Network slice selection assistance information (NSSAI) is used to indicate one or more single network slice selection assistance information (Single NSSAI, S-NSSAI) (or S-NSSAI list), and S-NSSAI is used to identify and distinguish different logical subnets.

The registration area (RA) of a terminal device includes one or more tracking areas (TA), each of which can provide services corresponding to different slices for the terminal device. TA is the operator's configuration at the cell level. Multiple cells can be configured with the same TA, and a cell can only belong to one TA. The slices supported by the RA of the terminal device can be represented by at least one of the following: Allowed NSSAI, Partially Allowed NSSAI, and/or Partially Rejected NSSAI. Assume that the slice services supported by the cell where the terminal device is currently located include services corresponding to slice 1 and slice 2, and slice 1 belongs to the allowed NSSAI in the RA of the terminal device. When the resources of slice 2 are congested or unavailable on the core network side, in order to ensure the continuity of the terminal device's services, a session associated with slice 1 (i.e., alternative S-NSSAI) may be established, and the service corresponding to slice 2 (i.e., original S-NSSAI) may be provided through the session, that is, the original S-NSSAI of the session is inconsistent with the alternative S-NSSAI.

When a terminal device moves from a source cell (i.e., the current cell) to a target cell, the session of the terminal device needs to be migrated from the management device of the source cell to the management device of the target cell. When the target cell can provide the service corresponding to the replacement S-NSSAI and cannot provide the service corresponding to the original S-NSSAI, how the target cell performs session migration processing on the session needs further study.

Summary of the invention

The embodiments of the present application provide a communication method and apparatus for improving the accuracy of session switching and improving communication efficiency when the original S-NSSAI and the replacement S-NSSAI of the session are inconsistent.

In a first aspect, an embodiment of the present application provides a communication method, the method comprising: a first device receives a switching request from a second device; the switching request is used to request to switch a first session to the first device; the network slice associated with the first session is the first network slice, and the first session is used to provide a terminal device with a service corresponding to the second network slice; the first device is a management device of a first cell, and the list of network slices supported by the first cell includes an identifier of the first network slice, but does not include an identifier of the second network slice; the first device receives first information from the second device; the first information is used to indicate that the processing method for the first session is to deny access or deactivate.

Using this method, when the first device receives a switching request, it also receives first information from the second device; when the network slice list supported by the first cell corresponding to the first device does not include the network slice actually served by the first session (the second network slice, i.e., the original S-NSSAI), the first information indicates that the processing method for the first session is to deny access or deactivate; thereby, the first device can process the first session according to the first information; that is, after the network slice replacement of the session occurs (i.e., the first network slice is different from the second network slice), during the switching process for the session, the first device (i.e., the target base station) can perform access control based on the slice originally associated with the session (i.e., the second network slice), thereby improving the accuracy of session switching and improving communication efficiency.

In a possible design, the first device may also deny access to or deactivate the first session based on the first information.

With such a design, even if the first cell can support the service corresponding to the network slice associated with the first session (the first network slice, i.e., replacing S-NSSAI), the first device can also deny access or deactivate the switching request of the first session based on the first information. In this way, the first information directly indicates the processing method of the first session, thereby improving the accuracy of session switching and improving communication efficiency.

In one possible design, the first information includes an identifier of the second network slice. When the network slice list does not include the identifier of the second network slice, the first device can also deny access to or deactivate the first session.

With such a design, even if the first cell can support the network slice associated with the first session (the first network slice, i.e., replacing S-NSSAI), the first device can also determine how to handle the first session by itself based on the identifier of the second network slice included in the first information. In this way, the first information can indirectly indicate the processing method of the first session, thereby improving the accuracy of session switching and improving communication efficiency.

In a possible design, the first information also includes: an identifier of at least one first-class network slice or an identifier of at least one second-class network slice; the first-class network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device, and the second-class network slice is a network slice that is not allowed to be used in a part of the registration area; the first device can also determine that the identifier of at least one first-class network slice includes the identifier of the second network slice; or, the first device can also determine that the identifier of at least one second-class network slice includes the identifier of the second network slice.

With such a design, the first device can also determine whether the network slice actually served by the first session belongs to a network slice allowed for use in a part of the registration area of the terminal device (or a network slice denied for use in a part of the registration area). In this way, when the first information indirectly indicates the processing method of the first session, the first device can further determine the processing method, thereby improving the accuracy of session switching and improving communication efficiency.

In one possible design, when the terminal device moves from the second cell to the first cell, the second device is a management device of the second cell, and the third device is a core network device.

With such a design, the second device (the management device of the second cell, or the source base station) can instruct the first device (the management device of the first cell, or the target base station) on how to handle the first session through the first information; for example, in an Xn-based switching scenario, the source base station can instruct the target base station on how to handle the session.

In one possible design, the first device may also send a first message to the second device based on the first information; the first message is used to indicate that the first device handles the first session by denying access or deactivating the session; the first device may also send a second message to the third device; the second message is used to indicate that resource establishment of the first session failed.

With such a design, the first device can indicate to the second device, based on the first information, that the processing method for the first session is to deny access or deactivate. Moreover, under the premise that the processing method is to deny access or deactivate, the first device may not establish resources for the first session, and indicate to the third device that the resource establishment of the first session has failed, thereby allowing the first device, the second device, and the third device to reach a consensus on the processing method for the first session, thereby improving communication efficiency.

In one possible design, the first device may also send a third message to the second device; the third message is used to indicate that the first device handles the first session as allowing access; the first device may also send a fourth message to the third device based on the first information; the fourth message is used to indicate that resource establishment of the first session failed.

With such a design, even if the first device indicates to the second device that the processing method for the first session is to allow access, the first device can also choose not to establish resources for the first session based on the first information, thereby interrupting the switching process of the first session, and the first device indicates to the third device that the resource establishment of the first session has failed, thereby ensuring that the request corresponding to the switching request of the first session is not executed, thereby improving the accuracy of session switching and improving communication efficiency.

In a possible design, the first device may also receive a first response message from the third device; the first response message is used to indicate the release of admission resources for the first session.

With such a design, the first device can receive a response message from the third device, so that the first device can release the access resources of the established first session, thereby reducing resource waste.

In one possible design, the first device may also send a third message to the second device; the third message is used to indicate that the first device handles the first session as allowing access; the first device may also send an eighth message to the third device; the eighth message is used to indicate that the resources for the first session are successfully established; the first device may also receive a second response message from the third device, and the second response message is used to indicate the release of the access resources for the first session.

With such a design, even if the first device sets the processing mode of the first session to allow access and establishes access resources for the first session, the first device may receive an instruction from the third device to release the access resources for the first session. That is to say, in the Xn-based switching scenario, the core network device can also instruct the target base station on the processing mode of the session, thereby interrupting the switching process of the first session, which can improve the accuracy of the session switching and improve the communication efficiency. Among them, the specific implementation method of the core network instructing the target base station to process the first session can refer to the discussion of the fourth aspect of the subsequent embodiments of this application, which will not be repeated here.

In one possible design, the second device is a core network device.

With such a design, the second device (core network device) can instruct the first device (the management device of the first cell, or the target base station) on how to handle the first session through the first information; for example, in an NG-based switching scenario, the core network device can instruct the target base station on how to handle the session.

In a possible design, the first device may also send a fifth message to the second device based on the first information; the fifth message is used to indicate that the first device handles the first session by denying access or deactivating the session.

In a possible design, the first device may also send a sixth message to the second device; the sixth message is used to indicate that the first device handles the first session as allowing access.

In a second aspect, an embodiment of the present application provides a communication method, the method comprising: a switching request sent by a second device to a first device; the switching request is used to request to switch a first session to the first device; the network slice associated with the first session is the first network slice, and the first session is used to provide the terminal device with a service corresponding to the second network slice; the first device is a management device of a first cell, and the list of network slices supported by the first cell includes an identifier of the first network slice; when the network slice list does not include the identifier of the second network slice, the second device sends first information to the first device; the first information is used to indicate that the processing method for the first session is to deny access or deactivate.

Using this method, when the list of network slices supported by the first cell corresponding to the first device does not include the network slice actually served by the first session (the second network slice, i.e., the original S-NSSAI), the second device can indicate through the first information that the processing method for the first session is to deny access or deactivate, so that the first device can correctly handle the switching request of the first session and improve communication efficiency.

In one possible design, the first information also includes an identifier of the second network slice.

With such a design, the first information includes the network slice actually served by the first session (the second network slice, i.e., the original S-NSSAI), so that the first device can determine by itself whether the first cell can support the service corresponding to the replacement S-NSSAI, thereby processing the switching request of the first session. In other words, the first information indirectly indicates the processing method of the first session, thereby improving the accuracy of session switching and improving communication efficiency.

In a possible design, the first information also includes: an identifier of at least one first-class network slice or an identifier of at least one second-class network slice; the first-class network slice is a network slice that is allowed to be used in part of the registration area of the terminal device, and the second-class network slice is a network slice that is not allowed to be used in part of the registration area.

With such a design, the first information also includes network slices allowed for use in some areas of the registration area (or network slices denied for use in some areas of the registration area). That is, when the first information indirectly indicates the processing method of the first session, the first device can further determine the processing method, thereby improving the accuracy of session switching and improving communication efficiency.

In a possible design, when the terminal device moves from the second cell to the first cell, the second device is a management device of the second cell.

With such a design, the second device (i.e., the management device of the second cell, or the source base station) can instruct the first device (the management device of the first cell, or the target base station) on how to handle the first session through the first information; for example, in an Xn-based switching scenario, the source base station can instruct the target base station on how to handle the session.

In a possible design, the second device can also receive second information from the terminal device; the second information includes an identifier of a second network slice; the second network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device, or the second network slice is a network slice that is not allowed to be used in a part of the registration area.

With such a design, the terminal device can determine the original S-NSSAI (i.e., the second network slice) corresponding to the first session, and can also determine that the original S-NSSAI is a network slice that is allowed (or not allowed) to be used in a part of the registration area of the terminal device; accordingly, the second device can obtain the second network slice through the terminal device, thereby determining how to handle the switching request for the first session.

In a possible design, the third device is a core network device, and the second device can also receive third information from the third device; the third information includes an identifier of the second network slice, and the third information also includes an identifier of at least one first-class network slice and/or an identifier of at least one second-class network slice list; the first-class network slice is a network slice that is allowed to be used in part of the registration area of the terminal device, and the second-class network slice is a network slice that is not allowed to be used in part of the registration area; the second device can also determine that the identifier of at least one first-class network slice includes the identifier of the second network slice; or, the second device determines that the identifier of at least one second-class network slice includes the identifier of the second network slice.

With such a design, the core network device can send "the original S-NSSAI (i.e., the second network slice) corresponding to the first session" and "the list of network slices related to the terminal device that are allowed (or not allowed) to be used in part of the registration area of the terminal device" to the second device through the third information; accordingly, the second device can obtain the third information to determine how to handle the switching request for the first session.

In a possible design, the second device may also receive a first message from the first device; the first message is used to indicate that the first device handles the first session by denying admission or deactivating the session.

With such a design, the second device can receive the first message, that is, receive the processing method of the first session by the first device, so that the processing method of the first session can be agreed upon between the first device and the second device, thereby improving communication efficiency.

In a possible design, the second device may also receive a third message from the first device; the third message is used to indicate that the first device handles the first session as allowing access.

With such a design, the second device can receive the third message, that is, receive the first device's processing method for the first session as allowing access, so that a consensus is reached between the first device and the second device on the processing method of the first session. The second device can perform the next step according to the third message, such as continuing the switching process of the first session (avoiding missing processing), thereby improving the accuracy of session switching and improving communication efficiency.

In one possible design, the second device is a core network device.

With such a design, the core network device can instruct the first device (the management device of the first cell, or the target base station) on how to handle the first session through the first information; for example, in an NG-based switching scenario, the core network device can instruct the target base station on how to handle the session.

In one possible design, the second device may also determine that the second network slice is a network slice that is allowed to be used in a partial area of the registration area of the terminal device; or, the second device determines that the second network slice is a network slice that is not allowed to be used in a partial area of the registration area.

With such a design, the second device can determine whether the network slice actually served by the first session belongs to a network slice allowed for use in part of the registration area of the terminal device (or a network slice denied for use in part of the registration area), thereby further determining the processing method for the first session, improving the accuracy of session switching, and improving communication efficiency.

In a possible design, the second device may also receive a fifth message from the first device; the fifth message is used to indicate that the first device handles the first session by denying admission or deactivating the session.

With this design, the second device can receive the fifth message, that is, receive the first device's processing method for the first session (denying access or deactivating), so that the processing method for the first session can reach a consensus between the first device and the second device, thereby improving communication efficiency.

In a possible design, the second device may also receive a sixth message from the first device; the sixth message is used to indicate that the first device handles the first session as allowing access.

With such a design, the second device can receive the sixth message, that is, receive the first device's processing method for the first session (allowing access), so that the processing method for the first session can reach a consensus between the first device and the second device, and the second device can perform the next step according to the sixth message, such as continuing the switching process of the first session (avoiding missing processing), thereby improving the accuracy of session switching and improving communication efficiency.

In a possible design, when the terminal device moves from the third cell to the first cell, the fourth device is the management device of the third cell, and the second device can also receive a handover request from the fourth device; the second device can also send a third response message to the fourth device; the third response message is used to indicate the release of the admission resources of the first session. The admission resources of the first session in the fourth device (base station side) can be the resources that the base station has allocated for the first session.

With such a design, the second device (core network device) can receive a switching request from the fourth device (the management device of the third cell, or the source base station) and instruct the fourth device to release the access resources of the first session, thereby reducing resource waste. It can also enable the core network device and the source base station to reach a consensus on the processing method of the first session, thereby improving the accuracy of session switching and improving communication efficiency.

In a possible design, when the terminal device moves from the third cell to the first cell, the fourth device is a management device of the third cell, and the second device can also receive the first information from the fourth device.

With such a design, the fourth device (the management device of the third cell, or the source base station) can send the first information to the first device (the management device of the first cell, or the source base station) by transparently transmitting through the second device (core network device), thereby indicating how to handle the switching request for the first session of the first device.

In a third aspect, an embodiment of the present application provides a communication method, the method comprising: a third device receives an eighth message from a first device; the eighth message is used to indicate that resources for a first session are successfully established; the network slice associated with the first session is the first network slice, and the first session is used to provide a service corresponding to a second network slice to a terminal device; the first device is a management device of a first cell, and a list of network slices supported by the first cell includes an identifier of the first network slice; when the network slice list does not include an identifier of the second network slice, the third device sends a second response message to the first device; the second response message is used to indicate the release of access resources for the first session; the third device is a core network device.

Using this method, under the premise that the first device indicates to the third device that the first session resource is successfully established, when the network slice list supported by the first cell corresponding to the first device does not include the network slice actually served by the first session (the second network slice, that is, the original S-NSSAI), The third device may also instruct the first device to release the access resources of the first session, thereby interrupting the switching process of the first session, so as to improve the accuracy of session switching and improve communication efficiency. Among them, the specific implementation method of the core network device instructing the target base station to handle the first session can refer to the discussion of the fourth aspect of the subsequent embodiments of this application, which will not be repeated here.

In one possible design, the third device determines that the second network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device; or, the third device determines that the second network slice is a network slice that is not allowed to be used in a part of the registration area.

With such a design, the third device can further determine whether the network slice actually served by the first session belongs to a network slice allowed for use in part of the registration area of the terminal device (or a network slice denied for use in part of the registration area), thereby improving the accuracy of session switching and improving communication efficiency.

In a fourth aspect, an embodiment of the present application provides a communication method, the method comprising: a fifth device receives a switching request, the switching request is used to request to switch a second session to a sixth device; the network slice associated with the second session is a first network slice, and the second session is used to provide a service corresponding to the second network slice to the terminal device; the fifth device is a core network device; the sixth device is a management device of a first cell, and the list of network slices supported by the first cell includes an identifier of the first network slice; when the network slice list does not include an identifier of the second network slice, the fifth device deactivates the second session.

Using this method, when the network slice list does not include the identifier of the second network slice, the fifth device (core network device) can deactivate the second session, thereby interrupting the switching process of the second session, thereby improving the accuracy of session switching and improving communication efficiency.

In one possible design, the fifth device may also determine that the second network slice is a network slice that is allowed to be used in a partial area of the registration area of the terminal device; or, the fifth device may also determine that the second network slice is a network slice that is not allowed to be used in a partial area of the registration area.

With such a design, the fifth device can further determine whether the network slice actually served by the second session belongs to a network slice allowed for use in a part of the registration area of the terminal device (or a network slice denied for use in a part of the registration area), thereby improving the accuracy of session switching and improving communication efficiency.

In one possible design, the fifth device may deactivate the second session in the following manner: the fifth device may receive a seventh message from the sixth device; the seventh message is used to indicate that the sixth device preprocesses the second session to allow access; when the network slice list does not include the identifier of the second network slice, the fifth device may deactivate the second session in response to the seventh message.

With such a design, even if the fifth device receives a pre-processing signal from the sixth device that the second session is allowed access, the fifth device can also determine to deactivate the second session based on the network slice list, thereby improving the accuracy of session switching and improving communication efficiency.

In a possible design, after receiving the switching request from the sixth device, the fifth device may also send fourth information to the sixth device; the fourth information is used to indicate the release of access resources for the second session.

With such a design, the fifth device can instruct the sixth device to release the access resources of the second session through the fourth information, thereby reducing resource waste.

In one possible design, when the switching request is used to request switching of the second session from the seventh device to the sixth device, the fifth device may also receive a switching request from the seventh device, and the fifth device may also send fifth information to the seventh device, where the fifth information is used to indicate the release of resources allocated by the aforementioned seventh device for the second session.

With such a design, the sixth device can instruct the seventh device (source base station) to release the resources allocated for the second session, thereby reducing resource waste.

In a fifth aspect, the present application further provides a communication device. The communication device can execute the above method design. The communication device can be a chip or circuit capable of executing the function corresponding to the above method, or a device including the chip or circuit.

In one possible design, the communication device includes a communication unit for receiving and sending data; the communication device also includes a processing unit for implementing the steps in the above method. The above functions can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more units corresponding to the above functions.

In a sixth aspect, the present application further provides a communication device. The communication device can execute the above method design. The communication device includes: a memory for storing computer executable program code; and a processor, the processor being coupled to the memory. The program code stored in the memory includes instructions, and when the processor executes the instructions, the communication device or a device equipped with the communication device executes the method in any possible design above.

The communication device may further include a communication interface; or, if the communication device is a chip or a circuit, the communication interface may be an input/output interface of the chip, such as an input/output pin.

In a seventh aspect, the present application provides a communication system, which includes a first device that executes the first aspect, and/or one or more devices in a second device that executes the second aspect.

Optionally, the communication system may further include a third device and/or a fourth device.

In an eighth aspect, the present application provides a communication system, comprising one or more devices in the fifth device, the sixth device, and/or the seventh device that execute the fourth aspect.

In a ninth aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program runs on a device, it executes the method in any one of the possible designs described above.

In a tenth aspect, the present application provides a computer program product, which includes a computer program. When the computer program runs on a device, it executes the method in any possible design described above.

In an eleventh aspect, the present application provides a chip comprising a processor and a memory; the processor is coupled to the memory and is used to read a computer program stored in the memory and execute a method in any possible design described above.

In addition, the technical effects brought about by the fifth to eleventh aspects can be found in the description of the first to fourth aspects above, and will not be repeated here.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a structural diagram of a communication system provided in an embodiment of the present application;

FIG2 is a schematic diagram of a communication scenario provided in an embodiment of the present application;

FIG3 is a schematic diagram of another communication scenario provided in an embodiment of the present application;

FIG4 is a schematic diagram of another communication scenario provided in an embodiment of the present application;

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

FIG6 is a flow chart of another communication method provided in an embodiment of the present application;

FIG7 is a flow chart of another communication method provided in an embodiment of the present application;

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

FIG9 is a schematic diagram of a flow chart of another communication method provided in an embodiment of the present application;

FIG10 is a schematic diagram of a flow chart of another communication method provided in an embodiment of the present application;

FIG11 is an exemplary diagram of a communication method provided in an embodiment of the present application;

FIG12 is an exemplary diagram of another communication method provided in an embodiment of the present application;

FIG13 is a schematic diagram of the structure of a communication device provided in an embodiment of the present application;

FIG14 is a schematic diagram of the structure of another communication device provided in an embodiment of the present application.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and beneficial effects of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

In the description of the present application, unless otherwise specified, "/" means or, for example, A/B can mean A or B; "and/or" in the present application is only a kind of association relationship describing the associated objects, indicating that there can be three relationships, for example, A and/or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the present application, "at least one" refers to one or more items, and "multiple items" refers to two or more items. In the description of the present application, words such as "first" and "second" are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. In the embodiment of the present application, "when...", "under...", and "if..." can represent the same meaning and can be replaced with each other.

The following is an explanation of the terms involved in this application:

(1)TA is a concept established for the location management of terminal devices. Both terminal devices and core network devices can obtain the TA of the terminal device. TA is an operator's configuration at the cell level. Multiple cells can be configured with the same TA, and a cell can only belong to one TA. Each TA can be indicated by a tracking area code (TAC) or a tracking area identity (TAI), where TAI is composed of a public land mobile network (PLMN) identity and a TAC.

(2) RA is a range determined by the core network device for the terminal device when the terminal device registers. The core network can track the terminal device within the RA. RA may include one or more TAs, and each RA may be indicated by the identifier of the TA it contains, such as TAC/TAI. For example, RA = {TAC#1, TAC#2}, which means: RA includes the TA identified by TAC#1 and the TA identified by TAC#2. In one implementation, The core network device may indicate the RA of the terminal device by sending a registration accept message to the terminal device.

(3) Network slicing. The physical network can be abstractly divided into multiple slices. Each slice constitutes an end-to-end logical subnet. Different slices are logically isolated. Each slice can flexibly provide one or more network services according to demand and will not affect other slices.

Different logical subnets can be identified and distinguished by S-NSSAI. Each S-NSSAI can include at least one of the following: slice/service type (SST), slice differentiator (SD). Among them, SST can indicate slice-specific characteristics and service types; SD, as a supplement to SST, can further distinguish multiple slice instances that meet the same SST, and SD is optional.

In the present application, S-NSSAI may be used to indicate a slice; NSSAI is an S-NSSAI list, which may include one or more S-NSSAIs, that is, one or more slices.

In one implementation, the slice list supported by a cell is pre-configured by the operation administration and maintenance (OAM) device according to the TA granularity. Taking the management device corresponding to the cell as a base station as an example, the base station can report the pre-configured slice list to the core network device when establishing an NG interface with the core network device; that is, the support for slices on the base station side is in line with TA homogeneous deployment, and all cells in a specific TA support the same slices. If the base station can also support centralized unit (CU)/distributed unit (DU) separation, further, the DU needs to first send the S-NSSAI list supported by each TA to the CU, and then the CU reports it to the core network device.

In one implementation, the types of NSSAI may include the following seven types:

The first type: Requested NSSAI: may include the network slices requested by the terminal device. For example, if the requested NSSAI includes slice #1 and slice #2, the network slices requested by the terminal device are slice #1 and slice #2.

In one implementation, the requested NSSAI may be carried in a registration request message.

The second type: Allowed NSSAI: may include the S-NSSAI allowed by the network side in the requested NSSAI of the terminal device. In one implementation, the allowed NSSAI may be indicated by the allowed NSSAI (Allowed NSSAI) information element in the registration accept message. The allowed NSSAI may include network slices allowed for use in all areas in the RA. For example, if the allowed NSSAI includes slice #1, and the RA includes a TA identified by TAC#1, then the network slice allowed for use in the TA identified by TAC#1 is slice #1.

The third type: Rejected NSSAI: may include the S-NSSAI rejected by the network side in the request NSSAI of the terminal device. The rejected NSSAI may include the network slices rejected for use in all areas of the RA. For example, if the rejected NSSAI includes slice #1, and the RA includes the TA identified by TAC#1, then the network slice rejected for use in the TA identified by TAC#1 is slice #1. In one implementation, the rejected NSSAI may be indicated by the rejected NSSAI (Rejected NSSAI) information element in the registration acceptance message. The rejected NSSAI may also indicate the partially rejected NSSAI in the RA (Rejected S-NSSAI(s) Partially in the RA), that is, the network slices rejected for use in some areas of the RA. For example, if the RA includes the TA identified by TAC#1 and the TA identified by TAC#2, and slice #2 cannot be supported by the TA identified by TAC#1 or slice #2 can only be supported by the TA identified by TAC#2, then the partially rejected NSSAI in the RA includes slice #2.

In one implementation, the partially rejected NSSAI in the RA may be indicated by the rejection reason for rejecting the NSSAI. For example, the rejection reason is partial rejection in the RA, and the terminal device may re-request the corresponding slice service in the area that can support the NSSAI in the RA based on the partially rejected NSSAI in the RA.

The fourth type: Partially Allowed NSSAI: It may include the S-NSSAI that is partially allowed by the network side in the requested NSSAI of the terminal device. The partially allowed NSSAI may include network slices that are allowed to be used in some areas in the RA. For example, if the RA includes a TA identified by TAC#1 and a TA identified by TAC#2, and slice #2 cannot be supported by the TA identified by TAC#1 or slice #2 can only be supported by the TA identified by TAC#2, then the partially allowed NSSAI includes slice #2.

In one implementation, partially allowed NSSAI may be indicated via a Partially Allowed NSSAI element in a Registration Accept message.

In some examples, partially allowed NSSAI and/or partially rejected NSSAI in RA may be used in conjunction with a TA list to indicate network slices allowed and/or rejected in some areas of RA. The TA list may be a list of TAs in RA that can support partially allowed NSSAI and/or partially rejected NSSAI in RA. For example, if RA includes a TA identified by TAC#1 and a TA identified by TAC#2, slice #2 cannot be supported by the TA identified by TAC#1 or slice #2 can only be supported by the TA identified by TAC#2, and the partially allowed NSSAI or partially rejected NSSAI in RA includes slice #2, then the TA list that can support the corresponding NSSAI includes the TA identified by TAC#2. In addition, the TA list may also be a list of TAs in RA that cannot support partially allowed NSSAI and/or partially rejected NSSAI in RA. In this case, in the above example, the partially allowed NSSAI or partially rejected NSSAI in RA includes slice #2, then the TA list that cannot support the corresponding NSSAI includes the TA identified by TAC#1.

In some other examples, one or more of the allowed NSSAI, the partially allowed NSSAI, and the partially rejected NSSAI in the RA may be Used in conjunction with the service area, it indicates the network slices that are allowed and/or denied in some areas of the RA. The service area may also be referred to as the Network Slice Area of Service (NS-AoS), which is used to indicate the area in the RA where resources are allocated or not allocated for the slice in the corresponding NSSAI, and the area may be an area determined based on the TA and the cell list. For example, if the RA includes a TA identified by TAC#1, and the TA identified by TAC#1 includes cells #1 to #4, but no resources are allocated to slice #2 in cell #2, and slice #2 belongs to an NSSAI that is allowed, partially allowed, or partially denied in the RA, then the service area for slice #2 includes cells #1, #3, and #4 in the TA identified by TAC#1.

It should be understood that the partially allowed NSSAI, the partially denied NSSAI in the RA, and the service area, etc. may also be named by other names as long as the same functions are achieved.

Fifth type: Subscribed NSSAI: Subscription data belonging to the user.

Type 6: Default NSSAI: According to the operator's policy, one or more of the user's subscribed NSSAIs may be set as the default NSSAI. If the terminal device does not carry the Allowed NSSAI in the registration request message (registration request), and there is a default NSSAI, the network side will use the default NSSAI to provide services to the terminal device.

Seventh type: Configured NSSAI: The network side configures the NSSAI for the terminal device to use. After receiving the parameters related to the configured NSSAI, the terminal device can determine which S-NSSAI(s) are available in the current network. The network side will carry the parameters related to the configured NSSAI in the "Configured NSSAI" information element of the registration accept message; if the configuration of the terminal device changes after registration, the network side will carry the parameters related to the configured NSSAI in the configuration update command to update the terminal device; the terminal device will save the corresponding configured NSSAI of each network side in the non-volatile storage space; each PLMN can only be configured with one configured NSSAI at most.

(4) Session: A connection between a terminal device, access network device, user plane network element, and data network (DN) established by a session management network element in a mobile communication system for a terminal device, and used to transmit user plane data between the terminal device and the DN. A session is, for example, a protocol data unit (PDU) session.

The terminal device can establish one or more PDU sessions with the mobile communication system (for example, 5G system), and one or more QoS flows can be established in each PDU session. Each QoS flow is used to transmit data with the same QoS requirement (reliability or latency) in a service. QoS flows can be identified by QoS flow identifiers (QFI).

The following introduces the architecture of the communication system to which the method provided in this application is applied.

FIG1 shows an architecture diagram of a communication system applicable to an embodiment of the present application, wherein the communication system includes a terminal device, an access network (core network) device, and a core network device. Optionally, the communication system may include multiple terminal devices and multiple access network devices.

Terminal device is a device with wireless transceiver function, which can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; it can also be deployed on the water (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons and satellites, etc.). Terminal devices can be mobile phones, tablet computers, computers with wireless transceiver functions, virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, user equipment (UE), etc. Terminal devices can realize the function of user access to the network.

Access network equipment is equipment in a wireless network, such as a radio access network (RAN) node or a radio access network device that connects a terminal device to a wireless network. At present, some examples of access network equipment include: next-generation base stations (gNodeB, gNB) in 5G, transmission reception points (TRP), evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved NodeB, or home Node B, HNB), base band unit (BBU), wireless fidelity (Wifi) access point (AP), integrated access and backhaul (IAB), etc. In one implementation, the access network device may also be an access network device in a future communication system (such as a 6G communication system). In an embodiment of the present application, different cells may provide services corresponding to different network slices for terminal devices, and the access network device is the management device of each cell.

The core network equipment provides user connection, user management, and service bearer, and provides an interface to the external network as a bearer network. The core network equipment may include at least one of the following network elements: a mobility management network element, a session management network element, a user plane network element, a data management network element (e.g., a unified data management (UDM) network element), a unified data repository (UDM), and a The network elements include network exposure function (NEF) network element, policy control network element (PCF) network element) or network repository function (NRF) network element. Some of these network elements are described below.

AMF is the main functional unit of the fifth generation (5G) core network, responsible for access control and mobility management capabilities, and ensuring the service continuity of terminal devices during mobility. In 5G, the mobility management network element can be an access and mobility management function (AMF) network element. In future communications such as the sixth generation (6G), the mobility management network element can still be an AMF network element, or have other names, which are not limited in this application.

SMF is responsible for managing the packet data unit (PDU) session of the terminal device. The PDU session is a channel for transmitting PDU. The terminal device needs to transmit PDU to each other with the DN through the PDU session. The PDU session is established, maintained and deleted by the SMF network element. The functions of the session management network element include: session management (such as session establishment, modification and release, including tunnel maintenance between user plane network elements and access network devices), selection and control of user plane network elements, service and session continuity (SSC) mode selection, roaming, etc. In 5G, the session management network element can be a session management function (SMF) network element. In future communications such as 6G, the session management network element can still be an SMF network element, or a network element with other names but with all or part of the functions of a session management network element. This application does not limit it.

Currently, in the RA of a terminal device, different cells may provide services corresponding to different network slices for the terminal device. In this way, when the terminal device moves between different cells, the management devices (i.e., access network devices) of each cell may need to switch and/or release the sessions associated with the network slices.

In one scenario example, when a terminal device that has signed up for a slice service initially joins the network, it can initiate a registration request for a specific network slice by carrying the Requested NSSAI in the radio resource control (RRC) setup complete message. After the aforementioned RRC setup complete message is transparently transmitted to the core network side via the base station (the base station does not parse the registration request), the core network device combines the subscription information of the terminal device in the unified data management (UDM) network element (i.e., subscribed NSSAI) to determine whether the network side (including the RAN side and the core network side) can provide services for the network slice service.

Based on this scenario example, the communication methods between devices for providing services corresponding to the network slice include the following methods A, B and C.

Method A:

If the core network device confirms that the current network can support the service corresponding to the Requested NSSAI, it will return the Allowed NSSAI and the RA range of the terminal device (indicated by the TAC/TAI list) to the terminal device through a registration request message (registration request); if the core network device confirms that the current network cannot support some or all of the S-NSSAI(s) in the Requested NSSAI, it will return the Allowed NSSAI and/or Rejected NSSAI (i.e., the S-NSSAI(s) in the Requested NSSAI that cannot be supported by the current network) and the RA range of the terminal device to the terminal device through a registration accept message. Accordingly, when the terminal device moves within the RA range, the terminal device cannot re-initiate a registration request for the Rejected NSSAI.

For example, as shown in FIG2 , the cells in the TA identified by TAC#1 only support slice #1; the cells in the TA identified by TAC#2 support slice #1 and slice #2. The terminal device can initiate a registration request in the TA identified by TAC#1 (carrying Requested NSSAI = slice #1, slice #2); since the TA identified by TAC#1 cannot support slice #2, after receiving the registration request of the terminal device, the core network device combines the Subscribed NSSAI of the terminal device and the support of the network slice on the base station side, and sends a registration accept message to the terminal device (carrying: Allowed NSSAI = slice #1, Rejected NSSAI = slice #2, RA = {TAC#1}). Based on this, the RA of the terminal device includes the TA identified by TAC#1, and does not include the TA identified by TAC#2. Among them, "{}" in this application represents a list, and "=" in this application represents "include", which is used here to explain Allowed NSSAI, Rejected NSSAI or RA, and will not be repeated later. When the terminal device moves within the RA, it cannot initiate a registration request for slice #2 again.

In some designs, the terminal device can initiate a session establishment request to the core network device based on the Allowed NSSAI (the non-access stratum (NAS) message can be transparently transmitted through the base station). After the core network device determines that it can support the session, it sends a session resource establishment request to the management device of the current cell of the terminal device (such as the base station), that is, one session is associated with one network slice (that is, the S-NSSAI associated with the network slice). After the base station determines and determines that resources can be allocated for the current session, it creates at least one corresponding DRB resource on the air interface.

Considering the mobility of terminal devices, the base station side can implement handover admission control based on network slices. For example, when a terminal device needs to perform inter-station handover, the source base station will send the established session and its associated network slice to the target base station; then, the target base station can decide whether to accept the admission of the above session based on its own support for network slices; if there is a PDU that the target base station does not support, If the target base station refuses to admit the PDU session, the source base station will release the resources corresponding to the session after the terminal device switches to the target base station. In other words, after the cell where the terminal device is currently located switches to the target base station, the PDU session is released on both the source base station and the target base station.

It should be understood that, limited by the scope of RA, sessions in mode A can only be associated with Allowed NSSAI.

Method B:

The network slices supported by the RA of the terminal device may be represented by at least one of the following: allowing NSSAI, partially allowing NSSAI, and/or partially rejecting NSSAI. In this way, on the basis of method A, the scope of the RA of the terminal device can be expanded, so that when the terminal device switches to a TA that supports partially allowing NSSAI (or partially rejecting NSSAI), the terminal device can re-initiate a registration request for partially allowing NSSAI (or partially rejecting NSSAI), so that a session associated with partially allowing NSSAI (or partially rejecting NSSAI) can be established.

For example, as shown in FIG3 , the cells within the TA identified by TAC#1 support slice #1, and the cells within the TA identified by TAC#2 support slice #1 and slice #2. If the requested NSSAI of the terminal device includes slice #1 and slice #2, the core network device may send a registration accept message to the terminal device (carrying: Allowed NSSAI = slice #1, Partially Allowed NSSAI = slice #2 (supported by the TA identified by TAC#2), RA = {TAC#1, TAC#2}; or, carrying: Allowed NSSAI = slice #1, Partially Rejected NSSAI = slice #2 can be supported by the TA identified by TAC#2/cannot be supported by the TA identified by TAC#1), RA = {TAC#1, TAC#2}). Obviously, the RA of the terminal device includes the TA identified by TAC#1 and the TA identified by TAC#2; slice #2 can be supported by the TA identified by TAC#2/cannot be supported by the TA identified by TAC#1. In this way, when the terminal device moves within the current RA, for example, when it moves to the TA identified by TAC#2, it can initiate a registration request for slice #2 again.

In some designs, a terminal device establishes a session associated with partially allowed NSSAI (or partially rejected NSSAI) in a TA (including the cell corresponding to the source base station) that can support partially allowed NSSAI (or partially rejected NSSAI); then, the terminal device moves from the source base station to the target base station, and the cell corresponding to the target base station is located in a TA that cannot support partially allowed NSSAI (or partially rejected NSSAI), then the previously established session will not be supported, and therefore the user plane resources of the session should be deactivated, that is, the target base station can deny access to the session or deactivate/suspend it.

Method C:

Assume that the cell where the terminal device is currently located can support the services corresponding to slice #1 and slice #2, and slice #1 is allowed NSSAI in the RA of the terminal device. When the resources of slice #2 (such as session resources) are congested or unavailable on the core network side, in order to ensure the continuity of the service of the terminal device, the network slice replacement process may be executed, that is, a session associated with slice #1 (that is, the replacement S-NSSAI) is established, and the service corresponding to slice #2 (that is, the original S-NSSAI) is provided through the session. In other words, the original S-NSSAI of the session is inconsistent with the replacement S-NSSAI.

Specifically, the core network device sends a mapping relationship between the original S-NSSAI and the replacement S-NSSAI to the terminal device. The time for the core network device to send the aforementioned mapping relationship to the terminal device is not limited (it does not necessarily need to rely on the session to establish the original S-NSSAI to trigger). Optionally, if the allowed NSSAI and/or configured NSSAI of the terminal device does not include the replacement S-NSSAI, the core network device can also add the replacement S-NSSAI to the allowed NSSAI and/or configured NSSAI of the terminal device.

After receiving the aforementioned mapping relationship, the terminal device can initiate a session based on the original S-NSSAI; in the process of initiating the session, it is necessary to carry the original S-NSSAI and the replacement S-NSSAI in the session establishment request. After receiving the session establishment request, the AMF network element in the core network device can send both of the above two S-NSSAIs to the SMF network element; the SMF network element can determine to establish a session associated with the replacement S-NSSAI. That is, the network slice replacement process is completed.

Based on the above scenario example, if the communication methods in method B and method C are combined, when the terminal device moves from the source cell (i.e., the current service cell managed by the source base station) to the target cell (i.e., the target service cell managed by the target base station), and during the session migration (i.e., session switching) of the terminal device, the following situation may occur: When the target cell can provide the service corresponding to the replacement S-NSSAI but cannot provide the service corresponding to the original S-NSSAI, the management device of the target cell cannot clearly know how to perform session migration processing on the session. In this application, session migration is session switching, the session migration process is the session switching process, and the session migration processing is the session switching processing.

For example, as shown in Figure 4, the RA of the terminal device = {TAC#1, TAC#2}, the cells in the TA identified by TAC#1 support slice #1, and the cells in the TA identified by TAC#2 support slice #1 and slice #2. The Allowed NSSAI of the terminal device in the RA = slice #1, the Partially Allowed NSSAI of the terminal device in the RA = slice #2 (or Partially Rejected NSSAI = slice #2), and the terminal device receives and saves the mapping relationship between slice #1 (replacing S-NSSAI) and slice #2 (original S-NSSAI) from the core network device.

In some designs, when the terminal device is located in the TA identified by TAC#2 (including the source cell), the terminal device can request to establish a session with the replacement S-NSSAI as slice #1 and the original S-NSSAI as slice #2; after the core network device completes the network slice replacement process, it instructs the source cell to establish a session associated with slice #1. With the movement of the terminal device, when the terminal device is located in the TA identified by TAC#1 (including the target cell), the source base station needs to migrate the established session with the target base station.

In traditional technology, when the target base station receives a handover request for a session, it can obtain the network slice associated with the session (i.e., replace the S-NSSAI); accordingly, the target base station may determine whether the TA to which it belongs supports the replacement S-NSSAI, thereby determining whether to perform admission processing on the session. For example, in the example shown in Figure 4 above, the network slice associated with the session is slice #1, the target base station is in the TA identified by TAC #1, and the TA identified by TAC #1 can support slice #1, so the target base station can perform admission processing on the session. However, since the session actually provides the service corresponding to slice #2, the TA where the target base station is located cannot support slice #2. Therefore, if the target base station performs admission processing on the session based on slice #2, the session should be denied admission or deactivated/suspended. In the above example, the target base station is not clear about the migration processing of the session during the handover process, which results in the target base station being unable to implement standardized admission control for network slices, and the accuracy of session switching is low.

In order to improve the accuracy of session switching and improve communication efficiency, an embodiment of the present application provides a communication method, which can be implemented in the communication system shown in the aforementioned FIG. 1 .

FIG5 is a schematic diagram of a communication method provided in an embodiment of the present application, the method comprising the following steps:

S501: The second device sends a handover request to the first device, the handover request is used to request to handover the first session to the first device; the network slice associated with the first session is the first network slice, and the first session is used to provide the terminal device with services corresponding to the second network slice; the first device is a management device of the first cell, and the list of network slices supported by the first cell includes the identifier of the first network slice. Accordingly, the first device receives the handover request from the second device; the handover request is used to request to handover the first session to the first device.

Optionally, the handover request can be carried in the handover request signaling.

In the communication system in Figure 1, the access network device is the management device of each cell. The first device may be any access network device in the communication system.

In one possible design, assuming that the management device of the cell where the terminal device is currently located is the source base station, before executing step S501, as shown in Figure 6 or Figure 7, the terminal device can interact with the source base station to implement the establishment process of the first session, or the source base station interacts with the previous base station that provides the service corresponding to the first session to implement the switching process of the first session, so that the terminal device can implement the service processing related to the first session through the source base station. In combination with the communication system shown in Figure 1, the access network device in the communication system includes a source base station; the terminal device can also obtain the mapping relationship between the original S-NSSAI (i.e., the second network slice) and the replacement S-NSSAI (i.e., the first network slice) from the AMF network element of the core network device. After the terminal device accesses the source base station, when the resources of the second network slice are congested or unavailable on the core network side, the terminal device can send a NAS message to the AMF network element, and the NAS message is used to request the establishment of a first session, which is associated with the first network slice and provides services corresponding to the second network slice. After receiving the NAS message, the AMF network element sends the identifier of the first network slice and the identifier of the second network slice to the SMF network element; when the SMF network element determines to establish the first session based on the identifiers of the two network slices, the AMF network element instructs the source base station to prepare resources related to the first session, thereby establishing the first session. Optionally, the AMF network element can instruct the source base station through NGAP signaling (for example, PDU session resources setup request).

In one possible design, when the terminal device moves and leaves the current cell, the operation of step S501 is triggered.

S502: When the list of network slices supported by the first cell does not include the identifier of the second network slice, the second device sends a first message to the first device. The first information is used to indicate that the processing method for the first session is to deny access or deactivate. Correspondingly, the first device receives the first information from the second device. It should be noted that this application does not limit the execution order of step S501 and step S502, that is, step S501 and step S502 can be executed simultaneously, and this application does not limit it.

Optionally, the first information may be carried in a handover request signaling. It should be understood that the handover request in step S501 and the first information in step S502 may be carried in the same handover request signaling, that is, the second device may send the handover request and the first information to the first device.

In an embodiment of the present application, a session may be a PDU session. The state of a PDU session may be in two stable states: active or inactive. Generally speaking, a successfully established PDU session is in an active state, and a successfully released PDU session is in an inactive state. The inactive state may also be referred to as a deactivated state.

Optionally, the "deactivation" processing method described in the embodiments of the present application can also be replaced by a "suspend" processing method for the session, which does not affect the implementation of the communication method in the embodiments of the present application.

Optionally, before the second device sends the first information to the first device, it can also determine whether the second network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device or a network slice that is not allowed to be used in a part of the registration area.

By adopting the method of step S501 and step S502, after the network slice of a session is replaced (i.e., the first network slice is different from the second network slice), during the switching process for the session, the first device (i.e., the target base station) can perform access control based on the slice originally associated with the session (i.e., the second network slice), thereby improving the accuracy of session switching and improving communication efficiency.

In a possible design, the first device may deny access to or deactivate the first session according to the first information. In this way, the first information directly indicates the processing method for the first session, which can improve the accuracy of session switching and improve communication efficiency.

Optionally, the aforementioned first information may include an identifier of the second network slice. When the list of network slices supported by the first cell does not include the identifier of the second network slice, the first device denies access to or deactivates the first session. In this way, the first information can also indirectly indicate the processing method for the first session, which can improve the accuracy of session switching and improve communication efficiency.

Optionally, the aforementioned first information may also include: an identifier of at least one first-class network slice or an identifier of at least one second-class network slice; the first-class network slice is a network slice that is allowed to be used in part of the registration area of the terminal device, and the second-class network slice is a network slice that is not allowed to be used in part of the registration area. Based on this, before the first device denies access to or deactivates the first session, the first device may also determine that the identifier of at least one first-class network slice includes the identifier of the second network slice; or, the first device may also determine that the identifier of at least one second-class network slice includes the identifier of the second network slice. In this way, the first device can further determine how to handle the first session, thereby improving the accuracy of session switching and improving communication efficiency.

In an embodiment of the present application, the interaction between access network devices (for example, between base stations) can be achieved through XnAP signaling, and the interaction between core network devices and access network devices (for example, between AMF network elements and base stations) can be achieved through NGAP signaling. The specific signaling and signal elements in the specific implementation methods below are all examples and are not limited in this application.

Based on the communication method shown in FIG5, in an Xn-based switching scenario, when the terminal device moves from the second cell to the first cell, the second device in the aforementioned steps S501 to S502 is the management device of the second cell, and the third device is the core network device. In conjunction with the communication system shown in FIG1, the second device can be any access network device in the communication system, and the second device is different from the first device; the third device can be a core network device in the communication system. Accordingly, the interaction between the first device and the second device can be achieved through XnAP signaling, and the interaction between the first device and the third device can be achieved through NGAP signaling. The specific signaling and information elements in the specific implementation methods below are examples, and this application does not limit them.

Based on the communication method shown in FIG5, in a possible design in a switching scenario based on Xn, as shown in FIG6, before executing step S502, the second device may also obtain the identifier of the second network slice, that is, obtain the original S-NSSAI of the session. The specific acquisition method may include the following method a and method b.

Method a: The second device receives second information from the terminal device; the second information includes an identifier of a second network slice; the second network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device, or the second network slice is a network slice that is not allowed to be used in a part of the registration area.

Optionally, the second information can be carried in an RRC message. For example, when requesting to establish a first session, the RRC message sent by the terminal device to the AMF network element carries a NAS request message, and the NAS request message is used to request to establish the first session; the RRC message can also carry the original S-NSSAI of the first session. It should be understood that before sending the RRC message, the terminal device has determined that the original S-NSSAI (i.e., the second network slice) is a network slice that is allowed to be used in part of the registration area of the terminal device or a network slice that is not allowed to be used in part of the registration area.

Method b: The second device receives third information from the third device; the third information includes an identifier of the second network slice, for example, the third information includes: the original S-NSSAI of the first session is the second network slice; the third information may also include an identifier of at least one first-class network slice and/or an identifier of at least one second-class network slice list; the first-class network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device, and the second-class network slice is a network slice that is not allowed to be used in a part of the registration area.

When method b is used to obtain the identifier of the second network slice, the second device can also determine that the identifier of at least one first-type network slice includes the identifier of the second network slice; or, the second device determines that the identifier of at least one second-type network slice includes the identifier of the second network slice.

Optionally, the third information may be carried in NGAP signaling (e.g., initial context setup request signaling).

Based on the communication method shown in FIG5 , in a possible design in a handover scenario based on Xn, before executing step S502, the second device may also obtain a list of network slices supported by the first cell, that is, a list of network slices supported by the TA where the first cell is located. The second device obtains the network slice list through XnAP signaling interaction. Further, the second device can combine the second information obtained by the aforementioned method a or the third information obtained by the aforementioned method b, and the network slice list supported by the first cell to determine that the network slice list supported by the first cell does not include the identifier of the second network slice.

Based on the communication method shown in FIG5 , in a possible design based on an Xn-based switching scenario, as shown in FIG6 , the subsequent operation of the aforementioned step S502 includes any one of the following methods: method 1, method 2, method 3, and method 4.

Method 1: The first device sends a first message to the second device according to the first information; the first message is used to indicate that the first device handles the first session by denying access or deactivating; the first device sends a second message to the third device; the second message is used to indicate that the resource establishment of the first session failed. Correspondingly, the third device receives the second message from the first device. The resource indicated in the resource establishment failure may be a radio bearer (e.g., a data radio bearer (DRB)) resource corresponding to the first session.

Optionally, the first device receives a first response message from the third device; the first response message is used to indicate the release of admission resources (eg, DRB resources) of the first session.

Optionally, the first message may be carried in XnAP signaling, for example, in a PDU session resources not admitted list (PDU session resources not admitted list) cell in a handover request acknowledgment signaling. The second message may be carried in NGAP signaling, for example, in a PDU session resource failed to setup list (PDU session resource failed to setup list) cell in a path switch request (path switch request) signaling. The first response message is carried in NGAP signaling (for example, a path switch request acknowledgment signaling), which is used to notify the first device of sessions whose user plane paths have been successfully switched and/or sessions whose user plane path switching fails and whose admission resources need to be released.

Using method 1, even if the first cell can support the first network slice associated with the first session, the first device will indicate in the XnAP signaling replied to the second device according to the first information (for example, through a first message indication) that the first session is denied access or deactivated; since the first session is processed by denying access or deactivation, the first device may not establish access resources for the first session, and send a message (second message) to the third device to indicate that resource establishment for the first session failed.

Mode 2: The first device sends a third message to the second device; the third message is used to indicate that the first device handles the first session as allowing access; the first device sends a fourth message to the third device based on the first information; the fourth message is used to indicate that the resource establishment of the first session failed. Correspondingly, the third device receives the fourth message from the first device. The resource indicated in the resource establishment failure may be a radio bearer (e.g., DRB) resource corresponding to the first session.

Optionally, the first device receives a first response message from the third device; the first response message is used to indicate the release of admission resources (eg, DRB resources) of the first session.

Optionally, the third message may be carried in the PDU session resources admitted list cell in the handover request acknowledge signaling. The fourth message may be carried in the PDU session resource failed to setup list cell of the path switch request signaling. The first response message is carried in NGAP signaling (e.g., path switch request acknowledge signaling), which is used to notify the first device of the session corresponding to the user plane path that has been successfully switched.

Using method 2, the first device indicates in the XnAP signaling (third message) replied to the second device that the first session is allowed access; in addition, the first device may not establish access resources for the first session according to the instructions of the first information, and send a message (fourth message) to the third session to indicate that the resource establishment of the first session failed, which can also ultimately achieve the denial of access or deactivation of the first session.

Method three: The first device deactivates the first session according to the first information, or ignores the processing requirements for the first session, and does not establish access resources (such as DRB resources); accordingly, the first device does not carry information related to the first session in the subsequent handover request-related messages (including handover request acknowledgment signaling) sent to the second device. The first device also does not carry information related to the first session in the subsequent handover request-related messages (including path switch request signaling) sent to the third device. For example, the handover request acknowledgment signaling sent by the first device to the second device includes a PDU session resources not admitted list element and a PDU session resources admitted list element, but the aforementioned PDU session resources not admitted list element and PDU session resources admitted list element do not include the identifier of the first session. For another example, the path switch request signaling sent by the first device to the third device includes a PDU session resource switching list (PDU session resource switched list) and a PDU session resource failed to setup list, but the aforementioned PDU session resource switched list and the aforementioned PDU session resource failed to setup list do not include an identifier of the first session. In addition, the first device may send a first message to the second device (reference method one); or, the first device may also send a third message to the second device (reference method two).

In the third approach, after receiving the first information, the first device does not process any subsequent operations of the first session, as an implementation approach of denying access, thereby interrupting the switching process of the first session.

Mode 4: The first device may also send a third message to the second device; the third message is used to instruct the first device to process the first session The method is to allow access. The first device may also send an eighth message to the third device; the eighth message is used to indicate that the resources of the first session are successfully established; accordingly, the third device receives the eighth message from the first device. When the list of network slices supported by the first cell does not include the identifier of the second network slice, the third device may also send a second response message to the first device, and the second response message is used to indicate the release of the access resources of the first session; accordingly, the first device receives the second response message from the third device.

Optionally, in the specific implementation process of method 4, before the third device determines to send a second response message to the first device, the third device may also make a judgment on the network slice (i.e., the second network slice) actually providing services for the first session and the list of network slices supported by the first cell. The judgment process may refer to the actions performed by the fifth device (i.e., the core network device) shown in subsequent steps S801 to S802 of this application, which will not be repeated here. The judgment process may include: the third device determines that the second network slice is a network slice that is allowed to be used in part of the registration area of the terminal device; or the third device determines that the second network slice is a network slice that is not allowed to be used in part of the registration area.

Thus, in method four, even if the first device sets the processing mode for the first session to allow access and establishes access resources for the first session, the first device may receive an instruction from the third device to release the access resources for the first session, thereby interrupting the switching process of the first session.

Based on the communication method shown in Figure 5, in the NG-based handover scenario, the second device in the aforementioned steps S501 to S502 is a core network device. Accordingly, the interaction between the first device and the second device can be implemented through NGAP signaling, and the specific signaling and information elements in the following specific implementation methods are all examples, and this application does not limit them.

Based on the communication method shown in Figure 5, in a possible design based on NG switching scenario, before executing step S501, the second device may also receive a switching request from the source base station; before executing step S502, the second device may also determine that the second network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device; or, the second device may also determine that the second network slice is a network slice that is not allowed to be used in a part of the registration area.

Based on the communication method shown in FIG. 5 , in a possible design based on an NG switching scenario, as shown in FIG. 7 , the subsequent operations of the aforementioned step S502 include the following method 1 and method 2.

Mode 1: The first device sends a fifth message to the second device according to the first information; the fifth message is used to indicate that the first device handles the first session by denying access or deactivating the session.

Optionally, the fifth message can be carried in the PDU session resource failed to setup list element in the handover request acknowledgement signaling.

Mode 2: The first device sends a sixth message to the second device; the sixth message is used to indicate that the first device should allow access to the first session.

Optionally, the sixth message can be carried in the PDU session resources admitted list element in the handover request acknowledgment signaling.

In the specific implementation process of method 2, although the first device indicates in the NGAP signaling (sixth message) replied to the second device that the first session is allowed to be admitted; in addition, the first device may not establish the admission resources (such as DRB resources) of the first session according to the instructions of the first information, and in fact may also realize the refusal of admission or deactivation of the first session.

Based on the communication method shown in FIG5 , in a possible design based on the NG handover scenario, when the terminal device moves from the third cell to the first cell, the fourth device is the management device of the third cell. The fourth device can be any access network device in the communication system shown in FIG1 , and the fourth device is different from the first device. Accordingly, the interaction between the first device and the fourth device can be implemented through XnAP signaling, and the specific signaling and information elements in the specific implementation methods below are examples, and this application does not limit them.

Optionally, before executing step S501, the second device may also receive a handover request (including a handover request of the first session) from the fourth device; after executing step S502, the second device may also send a third response message to the fourth device, the third response message being used to notify the fourth device of the session (including the first session) that needs to be released. The third response message may be carried in a handover command. Optionally, the second device may also deactivate the first session.

Optionally, before the second device sends the third response message to the fourth device, the second device may also make a judgment on the network slice of the first session and the network slice list of the first device. The judgment process may refer to the actions performed by the fifth device (i.e., the core network device) shown in subsequent steps S801 to S802 of this application, which will not be repeated here. The judgment process may include: the second device determines that the second network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device; or the second device determines that the second network slice is a network slice that is not allowed to be used in a part of the registration area.

Optionally, the second device may also receive the first information from the fourth device. That is, after the fourth device determines the first information, The fourth device may transparently transmit the first information to the first device through the second device (eg, the AMF network element in the core network device). Optionally, if the first information is sent by the aforementioned transparent transmission method, the second device does not need to parse the first information.

FIG8 is a schematic diagram of another communication method provided in an embodiment of the present application, the method comprising the following steps:

S801: The fifth device receives a switching request, where the switching request is used to request that the second session be switched to the sixth device; the network slice associated with the second session is the first network slice, and the second session is used to provide the terminal device with services corresponding to the second network slice; the fifth device is a core network device; the sixth device is a management device of the first cell, and the list of network slices supported by the first cell includes the identifier of the first network slice.

Optionally, the handover request can be carried in the handover request signaling.

In the communication system in Figure 1, the access network device is the management device of each cell. The sixth device may be any access network device in the communication system.

In a possible design, assuming that the management device of the cell where the terminal device is currently located is the source base station, and the sixth device is the target base station, before executing step S801, the terminal device can interact with the source base station, through the establishment process or switching process of the second session, so that the terminal device implements the service processing related to the second session through the source base station. The specific implementation of this design can refer to the description in step S501, which will not be repeated here.

In one possible design, when the terminal device moves and leaves the current cell, the operation of step S801 is triggered.

S802: When the list of network slices supported by the first cell does not include the identifier of the second network slice, the fifth device deactivates the second session.

Optionally, before the fifth device deactivates the second session, the fifth device may also determine that the second network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device; or, the fifth device may also determine that the second network slice is a network slice that is not allowed to be used in a part of the registration area.

Based on the communication method shown in FIG8 , in the Xn-based handover scenario, the fifth device is a core network device, and the sixth device is a target base station. Accordingly, the interaction between the fifth device and the source base station can be implemented through XnAP signaling, and the interaction between the fifth device and the sixth device can be implemented through NGAP signaling. The specific signaling and information elements in the following specific implementation methods are examples, and this application does not limit them.

Based on the communication method shown in FIG8 , in a possible design under the Xn-based handover scenario, as shown in FIG9 , before step S801, the source base station sends a handover request for the second session to the sixth device, and the sixth device performs access permission processing for the second session, for example, the sixth device establishes a radio bearer (e.g., DRB) resource corresponding to the second session. Correspondingly, the sixth device may send a fourth response message to the source base station, and the fourth response message is used to indicate that the sixth device pre-processes the second session in a manner that allows access. The fourth response message may be carried in the PDU session resources admitted list element in the handover request acknowledgment signaling.

Optionally, the sixth device may also send a switching request to the fifth device. The sixth device may also send a seventh message to the fifth device; the seventh message is used to indicate that the pre-processing mode of the sixth device for the second session is to allow access. Correspondingly, the fifth device may receive the seventh message from the sixth device.

Optionally, the seventh message may be carried in the PDU session resource to be switched in downlink list (PDU session resource to be switched in downlink list) element in the path switch request signaling.

Based on this design, when the list of network slices supported by the first cell does not include the identifier of the second network slice, the fifth device can deactivate the second session in response to the seventh message. In this way, even if the fifth device receives the pre-processing method of the sixth device for the second session as allowing access, the fifth device can determine to deactivate the second session according to the network slice list, thereby improving the accuracy of session switching and improving communication efficiency.

In a possible design after executing step S802, the fifth device may also send fourth information to the sixth device; the fourth information is used to indicate the release of admission resources for the second session.

Optionally, the fourth information can be carried in the PDU session resource released list (PDU session resource released list) element in the path switch request acknowledgement signaling.

Based on the communication method shown in FIG8 , in a possible design based on the NG switching scenario, as shown in FIG10 , before step S801, the seventh device may also send a switching request for one or more sessions (including the second session) to the fifth device; the switching request is used to request that the aforementioned one or more sessions (including the second session) be switched from the seventh device to the sixth device. The seventh device may be a source base station, that is, a management device of the cell where the terminal device is currently located. Accordingly, the interaction between the fifth device and the sixth device may be implemented through NGAP signaling, and the interaction between the fifth device and the seventh device may be implemented through NGAP signaling. The specific signaling in the specific implementation manner described below will be described. The commands and information elements are examples and are not limited in this application.

Based on the communication method shown in FIG8 , in a possible design under the NG-based handover scenario, after step S802, the fifth device may also send a handover request for one or more sessions (excluding the second session) to the sixth device, and the one or more sessions (excluding the second session) are sessions successfully established by the seventh device. The handover request may be carried in a handover request signaling, and the handover request for the one or more sessions may be carried in a PDU session resource setup list (PDU session resource setup list) cell in the handover request signaling.

Optionally, the sixth device may also send a fifth response message to the fifth device; the fifth response message is used to notify the fifth device of a successful session or a failed session of resource establishment, and the fifth response message does not include the second session. The fifth response message is carried in the handover request acknowledgement signaling.

Optionally, the fifth device may also send a sixth response message to the seventh device; the sixth response message is used to notify the seventh device of the session corresponding to the user plane path that has been successfully switched among the one or more sessions mentioned above (excluding the second session) or the session that needs to be released (including the second session). The sixth response message is carried in the handover command signaling.

FIG11 is an example diagram of a communication method provided by an embodiment of the present application, which shows a partial implementation of the communication method shown in FIG5 and FIG8, and is applied to the Xn-based switching scenario in the scenario shown in FIG4. The method can be applied to the communication system shown in FIG1. In this example, the aforementioned access network device includes a source base station (represented by S-gNB) and a target base station (represented by T-gNB), a terminal device (represented by UE), and the functions of the aforementioned core network device are implemented by AMF network elements and SMF network elements.

Step 1: Establish PDU Session #1.

After the UE accesses the S-gNB, the UE sends a NAS message to the AMF network element, which is used to request the establishment of a PDU session for slice #2. Since the UE has received the mapping relationship between slice #1 and slice #2, the UE will carry the slice identifiers of slice #1 and slice #2 in the NAS message. After receiving the NAS message sent by the UE, the AMF network element will further send the slice identifiers of slice #1 and slice #2 to the SMF network element. The SMF network element determines to establish the PDU Session #1 associated with slice #1, and the AMF network element instructs the S-gNB to prepare RAN side resources for PDU Session #1 through NGAP signaling (such as PDU session resources setup request signaling).

Step 2: The UE moves from the coverage of the S-gNB to the coverage of the T-gNB.

Based on this, S-gNB needs to switch the session corresponding to the UE (including PDU Session#1) to T-gNB. There are two different situations (Sol#1 and Sol#2).

Sol#1: Even if T-gNB can support the slice associated with the PDU session, S-gNB can also instruct T-gNB to deny admission or deactivate (or suspend) the PDU session. The implementation of Sol#1 can refer to the implementation method of the switching scenario based on Xn in Figure 5 above. The specific implementation process of Sol#1 is described as follows.

In the case of Sol#1, it can be achieved through the following two implementations (Opt#1 and Opt#2).

Opt#1 (an implementation method including steps 3 to 6, refer to the above-mentioned method 1):

Step 3-1: The S-gNB indicates the first session set and the second session set to the T-gNB through XnAP signaling (e.g., handover request signaling); the first session set includes one or more PDU sessions that have been established when the UE accesses the S-gNB; the second session set is used to indicate the sessions in the aforementioned one or more PDU sessions that need to be denied access or deactivated/suspended even if the associated slices can be supported by the T-gNB. Among them, the first session set includes PDU Session#1. It should be understood that the first session set can be used to implement the function of the handover request of PDU Session#1. For example, the first session set includes PDU Session#1, which can indicate: "Handover request for at least one session including PDU Session#1"; with reference to the communication method shown in Figure 5 or Figure 6, the second session set is used to implement the function of the first information.

Optionally, the indication method of the second session set can be direct indication or indirect indication. For example (direct indication), the second session set includes PDU Session#1. For another example (indirect indication), the second session set includes the original S-NSSAI of PDU Session#1; for another example, the second session set can also include the UE's partial allowed NSSAI (or partial rejected NSSAI). Based on this, the T-gNB can determine by itself that even if the associated slice can be supported by the T-gNB, the session still needs to be denied access or deactivated/suspended.

Optionally, before executing step 3-1, the S-gNB may obtain the original S-NSSAI associated with one or more sessions (including PDU Session#1) in the first session set and the UE's partial allowed NSSAI (or partial rejected NSSAI) based on the following Alts (Alt#1 and Alt#2), and obtain a list of network slices that can be supported by the T-gNB, thereby determining the aforementioned second session set.

Alt#1: S-gNB obtains the original S-NSSAI of the PDU session from the AMF network element and the UE's partially allowed NSSAI (or partially rejected NSSAI, this possibility will not be repeated later, but the partially allowed NSSAI in the subsequent embodiments can be replaced by partially rejected NSSAI); UE obtains the list of network slices supported by the target cell managed by T-gNB through XnAP signaling interaction. For example, S-gNB obtains the UE's partially allowed NSSAI as slice #2 from the AMF network element, and the original S-NSSAI of PDU Session #1 is also slice #2. Since the list of network slices supported by the target cell does not include slice #2, S-gNB can instruct T-gNB to reject or deactivate/suspend PDU Session #1 through the second session set.

Alt#2: When the UE requests to establish a PDU session in step 1, if the original S-NSSAI of the PDU session is a partially allowed NSSAI, the UE can add the original S-NSSAI indication in the RRC message containing the NAS request, so that the S-gNB obtains the original S-NSSAI of the PDU session; the S-gNB obtains the list of network slices supported by the target cell managed by the T-gNB through the XnAP signaling interaction. For example, when the UE requests to establish PDU Session#1 in step 1, the corresponding original S-NSSAI obtained is slice#2, and slice#2 is a partially allowed NSSAI. Since the list of network slices supported by the target cell does not include slice#2, the S-gNB can instruct the T-gNB to reject or deactivate/suspend PDU Session#1 through the second session set.

Step 4-1: Even if the T-gNB can support the slice #1 associated with PDU Session #1, it will indicate in the XnAP signaling (e.g., handover request acknowledgment signaling) replied to the S-gNB that PDU Session #1 is denied access. For example, the third session set (e.g., PDU session resources not admitted list information element) in the handover request acknowledgment signaling carries the PDU session identifier (PDU Session ID) of PDU Session #1. It should be understood that, with reference to the communication method shown in FIG. 5 or FIG. 6, the third session set can be used to implement the function of the first message.

Step 5-1: T-gNB notifies the AMF network element of the PDU session for which resource preparation failed on the RAN side through the fourth session set in NGAP signaling (e.g., path switch request signaling). For example, the fourth session set (PDU session resource failed to setup list information element) carries the PDU Session ID of PDU Session#1. It should be understood that, with reference to the communication method shown in FIG. 5 or FIG. 6, the fourth session set can be used to implement the function of the second message.

Step 6-1: The AMF network element notifies the T-gNB of the user plane path that has been successfully switched through NGAP signaling (e.g., path switch request acknowledgment signaling). Optionally, referring to the communication method shown in FIG. 5 or FIG. 6 , the AMF network element may also notify the T-gNB to release the access resources of PDU Session#1, for example, the AMF network element sends the aforementioned first response message to the T-gNB.

Opt#2 (another implementation of steps 3 to 6, refer to the above-mentioned method 2):

Step 3-2: The S-gNB indicates the first session set and the second session set to the T-gNB through XnAP signaling (e.g., handover request signaling). The specific implementation process can be referred to step 3-1 and will not be repeated here.

Step 4-2: T-gNB sets PDU Session #1 as admitted in the XnAP signaling (e.g., handover request acknowledge signaling) in reply to S-gNB, but does not actually prepare RAN side resources for the PDU session. For example, the fifth session set (e.g., PDU session resources admitted list IE) in the handover request acknowledge signaling carries the PDU Session ID of PDU Session #1, but does not establish air interface DRB resources for the PDU session. It should be understood that, with reference to the communication method shown in FIG. 5 or FIG. 6, the fifth session set can be used to implement the function of the third message.

Step 5-2: T-gNB notifies the AMF network element of the PDU sessions that have been admitted and the PDU sessions for which the RAN side resource preparation failed through NGAP signaling (e.g., path switch request signaling). It should be understood that, with reference to the communication method shown in FIG. 5 or FIG. 6, the action of step 5-2 can be implemented through the fourth message. The specific implementation process can refer to step 5-1, which will not be repeated here.

Step 6-2: The AMF network element notifies the T-gNB of the user plane path that has been successfully switched through NGAP signaling (e.g., path switch request acknowledge signaling). Optionally, referring to the communication method shown in FIG. 5 or FIG. 6, the AMF network element may also notify the T-gNB to release the access resources of PDU Session#1, for example, the AMF network element sends the aforementioned first response message to the T-gNB. For the specific implementation process, please refer to step 6-1.

Sol#2: T-gNB admits the PDU session according to the slice associated with the PDU session, and the AMF network element instructs T-gNB to release the resources of the PDU session on the RAN side (i.e., the T-gNB side) or deactivate (or suspend) the PDU session. The implementation of Sol#2 can refer to the implementation method based on the Xn switching scenario in Figure 8 above. The specific implementation process of Sol#2 is described as an example below.

In the case of Sol#2, it can be achieved through the following implementation (Opt#3).

Opt#3 (another way to implement steps 3 to 6):

Step 3-3: The S-gNB indicates the first session set to the T-gNB through XnAP signaling (e.g., handover request signaling), and the first session set includes PDU Session#1.

Step 4-3: T-gNB allows PDU Session #1 to be admitted according to slice #1 associated with PDU Session #1, and sets PDU Session #1 as admitted in the reply XnAP signaling (e.g., handover request acknowledge signaling). For example, PDU Session #1 is carried in the sixth session set (e.g., PDU session resources admitted list IE) in the handover request acknowledge signaling. PDU Session ID. At this time, T-gNB will prepare RAN side resources for PDU Session #1, that is, establish the RAN side resources of the PDU session. It should be understood that, with reference to the communication method shown in Figure 8 or Figure 9, the sixth session set can be used to implement the function of the fourth response message.

Step 5-3: T-gNB notifies the AMF network element of the PDU session that has been admitted through NGAP signaling (e.g., path switch request signaling), for example, through the seventh session set in the path switch request signaling (e.g., PDU session resource to be switched in downlink list information element) carrying the PDU Session ID of PDU Session #1. It should be understood that, with reference to the communication method shown in FIG8 or FIG9, the seventh session set can be used to implement the function of the switching request of PDU Session #1 and the function of the seventh message. For example, the seventh session set includes PDU Session #1, which can indicate: "a switching request for at least one session including PDU Session #1, and T-gNB has already performed admission processing on PDU Session #1".

Step 6-3: The AMF network element determines that the original S-NSSAI corresponding to PDU Session #1 is slice #2 that T-gNB cannot support; the AMF network element instructs T-gNB to release the RAN side resources prepared for PDU Session #1 through path switch request acknowledge signaling, for example, the PDU Session ID carrying PDU Session #1 in the eighth session set (e.g., PDU session resource released list information element) in the path switch request acknowledge signaling; the AMF network element may also reject or deactivate/suspend PDU Session #1. It should be understood that, with reference to the communication method shown in FIG. 8 or FIG. 9, the eighth session set may be used to implement the function of the fourth information.

Optionally, the AMF network element may further determine that slice #2 partially allows NSSAI (or partially rejects NSSAI) before sending the path switch request acknowledgment signaling.

FIG12 is an example diagram of another communication method provided by an embodiment of the present application, which shows a partial implementation of the communication method shown in FIG5 and FIG8, and is applied to the NG switching scenario in the scenario shown in FIG4. The method can be applied to the communication system shown in FIG1. In this example, the aforementioned access network equipment includes a source base station (represented by S-gNB) and a target base station (represented by T-gNB), a terminal device (represented by UE), and the functions of the aforementioned core network equipment are implemented by AMF network elements and SMF network elements.

Step a: Establish PDU Session #1. The specific implementation process can be referred to step 1 and will not be repeated here.

Step b: The UE moves from the coverage of the S-gNB to the coverage of the T-gNB.

Step c: The S-gNB indicates the ninth session set (refer to the aforementioned first session set) and/or the tenth session set (refer to the aforementioned second session set) to the AMF network element through NGAP signaling (such as handover required signaling); the ninth session set includes PDU Session#1. The specific implementation process can refer to step 3-1 and will not be repeated here. Optionally, the aforementioned tenth session set can be transparently transmitted to the T-gNB via the AMF network element. It should be understood that the ninth session set can be used to implement the function of the handover request of PDU Session#1. For example, the ninth session set includes PDU Session#1, which can indicate: "Handover request for at least one session including PDU Session#1"; with reference to the communication method shown in Figure 5, the tenth session set is used to implement the function of the first information.

After step c, each device handles PDU Session#1 in two different ways (Sol#3 and Sol#4).

Sol#3: Even if T-gNB can support the slice associated with the PDU session, T-gNB can also deny admission or deactivate (or suspend) the PDU session based on the instruction of the AMF network element. The implementation of Sol#3 can refer to the implementation method based on the NG switching scenario in Figure 5 above. The specific implementation process of Sol#3 is described as follows.

In the case of Sol#3, it can be achieved through the following two implementations (Opt#4 and Opt#5).

Opt#4 (an implementation method including steps d to f, refer to the above-mentioned method 1):

Step d-4: The AMF network element indicates the ninth session set and/or the tenth session set to the T-gNB through NGAP signaling (e.g., handover request signaling); wherein the tenth session set is used to indicate the sessions in the aforementioned one or more PDU sessions that need to be denied admission or deactivated/suspended even if the associated slices can be supported by the T-gNB. Optionally, the aforementioned tenth session set can be transparently transmitted from the S-gNB to the T-gNB via the AMF network element.

Optionally, the indication mode of the tenth session set may be direct indication or indirect indication. The specific implementation process may refer to step 3-1, which will not be described in detail here.

Step e-4: Even if the T-gNB can support slice #1 associated with PDU Session #1, it will indicate in the NGAP signaling (e.g., handover request acknowledgment signaling) replied to the AMF network element that PDU Session #1 is denied access. For example, the eleventh session set (PDU session resources failed to setup list information element) in the handover request acknowledgment signaling carries the PDU Session ID of PDU Session #1. It should be understood that, with reference to the communication method shown in FIG. 5 or FIG. 7, the eleventh session set can be used to implement the function of the fifth message.

Step f-4: The AMF network element may indicate the session to be released to the S-gNB via NGAP signaling (e.g., handover command signaling). For example, the twelfth session set (PDU session resource to release list cell) in the handover command signaling The PDU Session ID of PDU Session#1 is carried in the twelfth session set. It should be understood that, with reference to the communication method shown in FIG. 5 or FIG. 7 , the twelfth session set can be used to implement the function of the third response message.

Opt#5 (another implementation method including steps d to f, refer to the aforementioned method 2):

Step d-5: The AMF network element sends the ninth session set and/or the tenth session set to the T-gNB through NGAP signaling (e.g., handover request signaling). The specific implementation process can refer to step d-4 and will not be repeated here.

Step e-5: T-gNB sets PDU Session #1 as admitted in the reply NGAP signaling (e.g., handover request acknowledge signaling), but does not actually prepare RAN side resources for the PDU session. For example, the thirteenth session set (e.g., PDU session resources admitted list IE) in the handover request acknowledge signaling carries the PDU Session ID of PDU Session #1, but does not establish air interface DRB resources for the PDU session. It should be understood that, with reference to the communication method shown in FIG. 5 or FIG. 7, the thirteenth session set can be used to implement the function of the fourth message.

Step f-5: The AMF network element may indicate to the S-gNB the session to be released through NGAP signaling (e.g., handover command signaling). For example, the PDU Session ID of PDU Session#1 is carried in the fourteenth session set (PDU session resource to release list information element) in the handover command signaling. It should be understood that, with reference to the communication method shown in FIG. 5 or FIG. 7 , the fourteenth session set may be used to implement the function of the third response message.

Optionally, before the AMF network element executes step f-5, the AMF network element may further determine the admitted session indicated by the T-gNB. The judgment process includes: the AMF determines that the original S-NSSAI corresponding to the PDU Session#1 is the slice #2 that the T-gNB cannot support; Optionally, the AMF network element further determines that the slice #2 is partially allowed NSSAI (or partially rejected NSSAI).

Optionally, the AMF network element can also deactivate the PDU session.

Sol#4: The AMF network element deactivates (or suspends) the PDU session. Accordingly, the subsequent session-related signaling (such as handover request signaling) does not include the PDU session. The implementation of Sol#4 can refer to the implementation method in the NG-based handover scenario in Figure 8 above. The specific implementation process of Sol#4 is described as follows.

In the case of Sol#4, it can be achieved by the following implementation (Opt#6).

Opt#6 (another implementation method including steps d to f):

Step d-6: After the AMF network element determines that the original S-NSSAI corresponding to PDU Session #1 is slice #2 that T-gNB cannot support, the AMF network element can deactivate the PDU session so that the PDU Session ID of PDU Session #1 will not appear in the subsequent process. For example, after step d-6, the fifteenth session set (e.g., PDU session resource setup list cell) in the handover request signaling sent by the AMF network element to the T-gNB will not contain the PDU Session ID of the PDU session.

Optionally, the AMF network element may further determine that slice #2 is partially allowed NSSAI (or partially rejected NSSAI).

Step e-6: T-gNB performs admission control according to the established PDU session and its associated slices indicated by the AMF network element, and feeds back the sixteenth session set to the AMF network element through NGAP signaling (e.g., handover request acknowledgment signaling). The sixteenth session set is used to indicate the PDU session of successful/failed admission, and the sixteenth session set does not include PDU Session #1. It should be understood that, with reference to the communication method shown in FIG. 8 or FIG. 10, the sixteenth session set can be used to implement the function of the fifth response message.

Step f-6: The AMF network element may indicate to the S-gNB through NGAP signaling (e.g., through handover command signaling) that the resources for handover on the T-gNB side are ready. For example, the handover command signaling sent by the AMF network element to the S-gNB carries the seventeenth session set, which is used to indicate the successfully switched PDU sessions and/or the PDU sessions that need to be released, and the seventeenth session set does not include PDU Session#1. It should be understood that, with reference to the communication method shown in FIG8 or FIG10, the seventeenth session set can be used to implement the function of the sixth response message.

The method provided in the embodiment of the present application is introduced above in combination with the accompanying drawings. The communication device provided in the embodiment of the present application is introduced below in combination with the accompanying drawings.

Based on the same technical concept, the present application also provides a communication device, which is used to implement the communication method provided in the above embodiments. Referring to Figure 13, the communication device 1300 includes a communication unit 1301 and a processing unit 1302, the communication unit 1301 is used to receive and send data; the processing unit 1302 is used to implement the steps in the communication method shown in Figure 5 or Figure 8. The communication device 1300 can be applied to a terminal device, an access network device or a core network device in the communication system shown in Figure 1, and can implement the communication method provided in the above embodiments and examples of the present application. The functions of each unit in the communication device 1300 are introduced below.

In a possible example, the communication device 1300 can be used to implement the actions of the first device in Figure 5, Figure 6 or Figure 7. The communication unit 1301 is used to: receive a switching request from the second device; the switching request is used to request to switch the first session to the first device; the network slice associated with the first session is the first network slice, and the first session is used to provide the terminal device with a service corresponding to the second network slice; The first device is a management device of the first cell, and the list of network slices supported by the first cell includes the identifier of the first network slice, but does not include the identifier of the second network slice; the communication unit 1301 is also used to: receive first information from the second device; the first information is used to indicate that the processing method for the first session is to deny access or deactivate.

In one possible design, the processing unit 1302 is used to: deny access to or deactivate the first session based on the first information.

In one possible design, the first information includes an identifier of the second network slice. When the network slice list does not include the identifier of the second network slice, the processing unit 1302 is used to deny access to or deactivate the first session.

In a possible design, the first information also includes: an identifier of at least one first-class network slice or an identifier of at least one second-class network slice; the first-class network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device, and the second-class network slice is a network slice that is not allowed to be used in a part of the registration area; the processing unit 1302 is also used to: determine that the identifier of at least one first-class network slice includes the identifier of the second network slice; or, the processing unit 1302 is also used to: determine that the identifier of at least one second-class network slice includes the identifier of the second network slice.

In one possible design, when the terminal device moves from the second cell to the first cell, the second device is a management device of the second cell, and the third device is a core network device.

In one possible design, the communication unit 1301 is also used to: send a first message to a second device based on the first information; the first message is used to indicate that the first device handles the first session by denying access or deactivating the session; the communication unit 1301 is also used to: send a second message to a third device; the second message is used to indicate that resource establishment of the first session failed.

In one possible design, the communication unit 1301 is also used to: send a third message to the second device; the third message is used to indicate that the first device handles the first session as allowing access; the communication unit 1301 is also used to: send a fourth message to the third device based on the first information; the fourth message is used to indicate that resource establishment of the first session failed.

In a possible design, the communication unit 1301 is further used to: receive a first response message from a third device; the first response message is used to indicate the release of access resources for the first session.

In one possible design, the communication unit 1301 is also used to: send a third message to the second device; the third message is used to indicate that the first device handles the first session as allowing access; the communication unit 1301 is also used to: send an eighth message to the third device; the eighth message is used to indicate that the resources for the first session are successfully established; the communication unit 1301 is also used to: receive a second response message from the third device, and the second response message is used to indicate the release of the access resources for the first session.

In one possible design, the second device is a core network device.

In a possible design, the communication unit 1301 is further used to: send a fifth message to the second device based on the first information; the fifth message is used to indicate that the first device handles the first session by denying access or deactivating the session.

In a possible design, the communication unit 1301 is further used to: send a sixth message to the second device; the sixth message is used to indicate that the first device processes the first session as allowing access.

In another possible example, the communication device 1300 can be used to implement the actions of the second device in Figure 5, Figure 6 or Figure 7. The communication unit 1301 is used to: send a handover request to the first device; the handover request is used to request to switch the first session to the first device; the network slice associated with the first session is the first network slice, and the first session is used to provide the terminal device with a service corresponding to the second network slice; the first device is a management device of the first cell, and the list of network slices supported by the first cell includes the identifier of the first network slice; when the network slice list does not include the identifier of the second network slice, the communication unit 1301 is also used to: send first information to the first device; the first information is used to indicate that the processing method for the first session is to deny access or deactivate.

In one possible design, the first information also includes an identifier of the second network slice.

In a possible design, the first information also includes: an identifier of at least one first-class network slice or an identifier of at least one second-class network slice; the first-class network slice is a network slice that is allowed to be used in part of the registration area of the terminal device, and the second-class network slice is a network slice that is not allowed to be used in part of the registration area.

In a possible design, when the terminal device moves from the second cell to the first cell, the second device is a management device of the second cell.

In a possible design, the communication unit 1301 is also used to: receive second information from the terminal device; the second information includes an identifier of a second network slice; the second network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device, or the second network slice is a network slice that is not allowed to be used in a part of the registration area.

In a possible design, the third device is a core network device, and the communication unit 1301 is further used to: receive third information from the third device; the third information includes an identifier of the second network slice, and the third information also includes an identifier of at least one first-class network slice and/or an identifier of at least one second-class network slice list; the first-class network slice is a network slice allowed to be used in a part of the registration area of the terminal device. The second type of network slice is a network slice that is not allowed to be used in part of the registration area; the processing unit 1302 is used to: determine that the identifier of at least one first type of network slice includes the identifier of the second network slice; or the processing unit 1302 is used to: determine that the identifier of at least one second type of network slice includes the identifier of the second network slice.

In a possible design, the communication unit 1301 is further used to: receive a first message from the first device; the first message is used to indicate that the first device handles the first session by denying access or deactivating the session.

In one possible design, the communication unit 1301 is further used to: receive a third message from the first device; the third message is used to indicate that the first device handles the first session as allowing access.

In one possible design, the second device is a core network device.

In one possible design, the processing unit 1302 is used to: determine that the second network slice is a network slice that is allowed to be used in a partial area of the registration area of the terminal device; or, the processing unit 1302 is used to: determine that the second network slice is a network slice that is not allowed to be used in a partial area of the registration area.

In a possible design, the communication unit 1301 is further used to: receive a fifth message from the first device; the fifth message is used to indicate that the first device handles the first session by denying access or deactivating the session.

In a possible design, the communication unit 1301 is further used to: receive a sixth message from the first device; the sixth message is used to indicate that the first device processes the first session as allowing access.

In one possible design, when the terminal device moves from the third cell to the first cell, the fourth device is the management device of the third cell, and the communication unit 1301 is also used to: receive a switching request from the fourth device; the communication unit 1301 is also used to: send a third response message to the fourth device; the third response message is used to indicate the release of the access resources of the first session.

In a possible design, when the terminal device moves from the third cell to the first cell, the fourth device is a management device of the third cell, and the communication unit 1301 is further used to: receive first information from the fourth device.

In another possible example, the communication device 1300 can be used to implement the actions of the third device in Figure 5 or Figure 6. The communication unit 1301 is used to: receive an eighth message from the first device; the eighth message is used to indicate that the resources of the first session are successfully established; the network slice associated with the first session is the first network slice, and the first session is used to provide the terminal device with a service corresponding to the second network slice; the first device is a management device of the first cell, and the list of network slices supported by the first cell includes the identifier of the first network slice; when the network slice list does not include the identifier of the second network slice, the communication unit 1301 is also used to: send a second response message to the first device; the second response message is used to indicate the release of the access resources of the first session; the third device is a core network device.

In one possible design, the processing unit 1302 is used to: determine that the second network slice is a network slice that is allowed to be used in a partial area of the registration area of the terminal device; or, the processing unit 1302 is also used to: determine that the second network slice is a network slice that is not allowed to be used in a partial area of the registration area.

In another possible example, the communication device 1300 can be used to implement the actions of the fifth device in Figure 8, Figure 9 or Figure 10. The communication unit 1301 is used to: receive a switching request, the switching request is used to request to switch the second session to the sixth device; the network slice associated with the second session is the first network slice, and the second session is used to provide the terminal device with a service corresponding to the second network slice; the fifth device is a core network device; the sixth device is a management device of the first cell, and the list of network slices supported by the first cell includes the identifier of the first network slice; when the network slice list does not include the identifier of the second network slice, the processing unit 1302 is used to: deactivate the second session.

In one possible design, the processing unit 1302 is also used to: determine that the second network slice is a network slice that is allowed to be used in a partial area of the registration area of the terminal device; or, the processing unit 1302 is also used to: determine that the second network slice is a network slice that is not allowed to be used in a partial area of the registration area.

In one possible design, the communication unit 1301 is also used to: receive a seventh message from a sixth device; the seventh message is used to indicate that the sixth device's preprocessing method for the second session is to allow access; when the network slice list does not include the identifier of the second network slice, the processing unit 1302 is also used to: deactivate the second session in response to the seventh message.

In a possible design, the communication unit 1301 is further used to: after receiving a switching request from a sixth device, send fourth information to the sixth device; the fourth information is used to indicate the release of access resources for the second session.

In one possible design, when the switching request is used to request switching the second session from the seventh device to the sixth device, the communication unit 1301 is also used to: receive a switching request from the seventh device, and the communication unit 1301 is also used to: send fifth information to the seventh device, and the fifth information is used to indicate the release of resources allocated by the aforementioned seventh device for the second session.

Based on the same technical concept, the embodiment of the present application also provides another communication device, the communication device 1400 can implement the communication method provided in the above embodiment, and has the functions of the communication device 1300 provided in the above embodiment. Referring to FIG. 14, the communication device 1400 includes: a memory 1402 and a processor 1401. Optionally, the communication device 1400 also includes a communication interface 1403. The communication interface 1403, the processor 1401 and the memory 1402 are connected to each other.

Optionally, the communication interface 1403, the processor 1401 and the memory 1402 are interconnected via a bus 1404. The bus 1404 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, FIG14 is represented by only one thick line, but it does not mean that there is only one bus or one type of bus.

The communication interface 1403 is used to receive and send signals to achieve communication with other devices other than the communication device.

The functions of the processor 1401 can refer to the description in the above embodiments, and will not be repeated here. Among them, the processor 1401 can be a central processing unit (CPU), a network processor (NP) or a combination of CPU and NP, etc. The processor 1401 can further include a hardware chip. The above-mentioned hardware chip can be an application-specific integrated circuit (ASIC), a programmable logic device (PLD) or a combination thereof. The above-mentioned PLD can be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL) or any combination thereof. When the processor 1401 realizes the above-mentioned functions, it can be realized by hardware, and of course, it can also be realized by executing the corresponding software through hardware.

The memory 1402 is used to store program instructions, etc. Specifically, the program instructions may include program codes, which include computer operation instructions. The memory 1402 may include random access memory (RAM), and may also include non-volatile memory (non-volatile memory), such as at least one disk storage. The processor 1401 executes the program instructions stored in the memory 1402 to implement the above functions, thereby implementing the method provided in the above embodiment. Exemplarily, the memory 1402 may include the first device, the second device, the third device, the fourth device, the fifth device, the sixth device or the seventh device shown in the embodiment of the present application.

Based on the same technical concept, an embodiment of the present application further provides a computer program, which, when executed on a computer, enables the computer to execute the method provided in the above embodiment.

Based on the same technical concept, an embodiment of the present application further provides a computer-readable storage medium, in which a computer program is stored. When the computer program runs on a computer, the computer executes the method provided in the above embodiment.

The storage medium may be any available medium that can be accessed by a computer. For example, but not limited to, a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer.

Based on the same technical concept, an embodiment of the present application further provides a chip, which is used to read a computer program stored in a memory to implement the method provided in the above embodiment.

Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

The present application is described with reference to the flowchart and/or block diagram of the method, device (system), and computer program product according to the present application. It should be understood that each process and/or box in the flowchart and/or block diagram, as well as the combination of the process and/or box in the flowchart and/or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the function specified in one process or multiple processes in the flowchart and/or one box or multiple boxes in the block diagram.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims (32)

A communication method, characterized in that the method comprises: The first device receives a switching request from the second device; the switching request is used to request to switch a first session to the first device; the network slice associated with the first session is the first network slice, and the first session is used to provide a service corresponding to the second network slice for the terminal device; the first device is a management device of a first cell, and the list of network slices supported by the first cell includes an identifier of the first network slice, but does not include an identifier of the second network slice; The first device receives first information from the second device; the first information is used to indicate that a processing method for the first session is to deny admission or deactivate. The method according to claim 1, characterized in that the method further comprises: The first device denies admission to or deactivates the first session according to the first information. The method according to claim 1, wherein the first information includes an identifier of the second network slice, and the method further comprises: When the network slice list does not include the identifier of the second network slice, the first device denies admission to or deactivates the first session. The method according to claim 3 is characterized in that the first information further includes: an identifier of at least one first-type network slice or an identifier of at least one second-type network slice; the first-type network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device, and the second-type network slice is a network slice that is not allowed to be used in a part of the registration area; the method further includes: The first device determines that the identifier of the at least one first-type network slice includes the identifier of the second network slice; Alternatively, the first device determines that the identifier of the at least one second-type network slice includes the identifier of the second network slice. The method as described in any one of claims 1-4 is characterized in that when the terminal device moves from the second cell to the first cell, the second device is a management device of the second cell, and the third device is a core network device. The method according to claim 5, characterized in that the method further comprises: The first device sends a first message to the second device according to the first information; the first message is used to indicate that the first device processes the first session in a manner of denying access or deactivating; The first device sends a second message to the third device; the second message is used to indicate that resource establishment of the first session fails. The method according to claim 5, characterized in that the method further comprises: The first device sends a third message to the second device; the third message is used to indicate that the first device processes the first session in a manner of allowing access; The first device sends a fourth message to the third device according to the first information; the fourth message is used to indicate that resource establishment of the first session fails. The method according to claim 6 or 7, characterized in that the method further comprises: The first device receives a first response message from the third device; the first response message is used to indicate the release of admission resources of the first session. The method according to claim 5, characterized in that the method further comprises: The first device sends a third message to the second device; the third message is used to indicate that the first device processes the first session in a manner of allowing access; The first device sends an eighth message to the third device; the eighth message is used to indicate that resources of the first session are successfully established; The first device receives a second response message from the third device, wherein the second response message is used to indicate the release of the first session Access resources for calls. The method according to any one of claims 1-4 is characterized in that the second device is a core network device. The method according to claim 10, characterized in that the method further comprises: The first device sends a fifth message to the second device according to the first information; the fifth message is used to indicate that the first device handles the first session in a manner of denying admission or deactivating. The method according to claim 10, characterized in that the method further comprises: The first device sends a sixth message to the second device; the sixth message is used to indicate that the first device processes the first session in a manner of allowing access. A communication method, characterized in that the method comprises: A handover request sent by the second device to the first device; the handover request is used to request to switch the first session to the first device; the network slice associated with the first session is the first network slice, and the first session is used to provide the terminal device with a service corresponding to the second network slice; the first device is a management device of the first cell, and the list of network slices supported by the first cell includes an identifier of the first network slice; When the network slice list does not include the identifier of the second network slice, the second device sends first information to the first device; the first information is used to indicate that the processing method for the first session is to deny access or deactivate. The method as claimed in claim 13 is characterized in that the first information also includes an identifier of the second network slice. The method as claimed in claim 13 or 14 is characterized in that the first information also includes: an identifier of at least one first-class network slice or an identifier of at least one second-class network slice; the first-class network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device, and the second-class network slice is a network slice that is not allowed to be used in a part of the registration area. The method as described in any one of claims 13-15 is characterized in that when the terminal device moves from the second cell to the first cell, the second device is a management device of the second cell. The method according to claim 16, characterized in that the method further comprises: The second device receives second information from the terminal device; the second information includes an identifier of the second network slice; the second network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device, or the second network slice is a network slice that is not allowed to be used in a part of the registration area. The method according to claim 16 or 17, wherein the third device is a core network device, and the method further comprises: The second device receives third information from the third device; the third information includes an identifier of the second network slice, and the third information also includes an identifier of at least one first-type network slice and/or an identifier of at least one second-type network slice list; the first-type network slice is a network slice that is allowed to be used in a part of the registration area of the terminal device, and the second-type network slice is a network slice that is not allowed to be used in a part of the registration area; The second device determines that the identifier of the at least one first-type network slice includes the identifier of the second network slice; or, the second device determines that the identifier of the at least one second-type network slice includes the identifier of the second network slice. The method according to any one of claims 13 to 18, characterized in that the method further comprises: The second device receives a first message from the first device; the first message is used to indicate that the first device handles the first session in a manner of denying admission or deactivating. The method according to any one of claims 13 to 19, characterized in that the method further comprises: The second device receives a third message from the first device; the third message is used to indicate that the first device should allow access to the first session. The method as described in any one of claims 13-15 is characterized in that the second device is a core network device. The method according to claim 21, characterized in that the method further comprises: The second device determines that the second network slice is a network slice that is allowed to be used in a partial area of the registration area of the terminal device; or, the second device determines that the second network slice is a network slice that is not allowed to be used in a partial area of the registration area. The method according to claim 21 or 22, characterized in that the method further comprises: The second device receives a fifth message from the first device; the fifth message is used to indicate that the first device handles the first session in a manner of denying admission or deactivating. The method according to claim 21 or 22, characterized in that the method further comprises: The second device receives a sixth message from the first device; the sixth message is used to indicate that the first device processes the first session in a manner of allowing access. The method according to any one of claims 21 to 24, characterized in that when the terminal device moves from the third cell to the first cell, the fourth device is a management device of the third cell, and the method further comprises: The second device receives the switching request from the fourth device; The second device sends a third response message to the fourth device; the third response message is used to indicate that the processing method for the first session is to deny admission or deactivate. The method according to any one of claims 21 to 25, characterized in that when the terminal device moves from the third cell to the first cell, the fourth device is a management device of the third cell, and the method further comprises: The second device receives the first information from the fourth device. A communication device, characterized in that it comprises: a communication unit and a processing unit; The communication unit is used to receive and send data; The processing unit is used to execute the method as described in any one of claims 1-26. A communication device, characterized in that it comprises: at least one processor and a memory; The at least one processor is coupled to the memory, and the at least one processor is configured to read the computer program stored in the memory to execute the method according to any one of claims 1 to 26. A computer-readable storage medium, characterized in that the computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are called by a computer, the computer executes the method as described in any one of claims 1-26. A chip system, characterized by comprising a communication interface and a processor: The communication interface is used to input and/or output signaling or data; The processor is used to execute a computer executable program so that a device equipped with the chip system executes a method as described in any one of claims 1 to 26. A computer program product, characterized in that computer executable instructions are stored in the computer program product, and when the computer executable instructions are called by a computer, the computer executes the method as described in any one of claims 1-26. A communication system, characterized in that it includes a first device and a second device, wherein the first device is used to execute the method as described in any one of claims 1-12, and the second device is used to execute the method as described in any one of claims 13-26.