CN115119279A

CN115119279A - Access control method and communication device

Info

Publication number: CN115119279A
Application number: CN202110307851.0A
Authority: CN
Inventors: 朱强华; 李文正; 吴问付
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-03-23
Filing date: 2021-03-23
Publication date: 2022-09-27

Abstract

The application discloses an access control method and a communication device, wherein the method comprises the following steps: for the terminal device switched from the second communication system to the first communication system, the access and mobility management functions may perform access control on the terminal device according to a CAG subscription of the terminal device. If the first access network device to which the terminal device is switched does not support the CAG subscription of the terminal device, the access and mobility management function may instruct the first access network device to initiate an intra-system switching or release procedure so as to switch the terminal device to a cell under the access network device supporting the CAG subscription in the first communication system, thereby avoiding a switching or access failure and improving a success rate of cross-system switching.

Description

Access control method and communication device

Technical Field

The present application relates to the field of wireless communications technologies, and in particular, to an access control method and a communications apparatus.

Background

A non-public network (NPN) is a non-public fifth generation (5 GS) communication network used to provide network services to specific users. The NPN may be implemented depending on a support of a Public Land Mobile Network (PLMN) or may be implemented independently of a support of a PLMN. The NPN that is realized depending on the support of the PLMN is referred to as a public network integrated NPN (PNI-NPN).

To control the terminal device to access the PNI-NPN, the access network device may use a Closed Access Group (CAG) function. The CAG function refers to: on one hand, one or more CAGs supported by the CAG cell are broadcasted by the CAG cell, each CAG can identify a group of terminal equipment, only the terminal equipment in the group is allowed to access the corresponding CAG cell, and other terminal equipment is not allowed to access the corresponding CAG cell; on the other hand, the terminal device is configured with a CAG subscription, which informs whether the terminal device can only access 5GS through a CAG cell, and which CAGs it is allowed to access (or which CAGs are available). In this way, in 5GS, the CAG cell may determine whether to allow the terminal device to access according to the CAG subscription of the terminal device.

When a terminal device is switched from an Evolved Packet System (EPS) to a 5GS system, because an access control mechanism is not perfect enough, a CAG access of the terminal device cannot be controlled, which may cause the terminal device to be switched to a cell of an access network device that does not support a CAG subscription.

Disclosure of Invention

In the embodiment of the application, an access control method and a communication device are used for performing access control according to a CAG subscription of a terminal device in a cross-system switching scene, so that the terminal device is switched to a cell of an access network device supporting the CAG subscription, switching or access failure is avoided, and the success rate of cross-switching is effectively improved.

In a first aspect, embodiments of the present application provide a cross-system handover method, which may be performed by an access and mobility management function, or may be performed by a component (e.g., a chip or a circuit) configured to the access and mobility management function.

The method comprises the following steps: the access and mobility management function of the first communication system acquires a CAG subscription of the terminal equipment, and the terminal equipment is switched from the second communication system to first access network equipment of the first communication system; the access and mobility management function instructs the first access network device to initiate an intra-system handover or release procedure, and the first access network device does not support the CAG subscription of the terminal device.

In the above technical solution, for a terminal device that is switched from the second communication system to the first communication system, the access and mobility management function may perform access control on the terminal device according to a CAG subscription of the terminal device. If the first access network device to which the terminal device is switched does not support the CAG subscription of the terminal device, the access and mobility management function may instruct the first access network device to initiate an intra-system switching or release procedure so as to switch the terminal device to a cell under the access network device supporting the CAG subscription in the first communication system, thereby avoiding a switching or access failure and improving a success rate of cross-system switching.

In one possible design of the first aspect, the terminal device has an ongoing session associated with PNI-NPN information, the PNI-NPN information comprising S-NSSAI and/or DNN.

In a possible design of the first aspect, the CAG subscription of the terminal device is used to indicate an identity of one or more CAGs allowed by the terminal device and/or whether the terminal device is allowed to access the first communication system only through a CAG cell.

In one possible design of the first aspect, the method further includes: the access and mobility management function receives cell CAG capability information from first access network equipment, wherein the cell CAG capability information is used for indicating whether a cell of the first access network equipment supports a CAG function, and if so, the cell CAG capability information is also used for indicating one or more CAG identifiers supported by the cell; and the access and mobility management function judges whether the first access network equipment supports CAG subscription of the terminal equipment or not according to the CAG capability information of the cell.

In a possible design of the first aspect, the first access network device does not support CAG subscription of the terminal device, and the method includes: a cell of first access network equipment supports a CAG function, but the identification of one or more CAGs supported by the cell is not the identification of a CAG allowed by terminal equipment; or, the cell of the first access network device does not support the CAG function, but the terminal device only allows access to the first communication system through the CAG cell.

In one possible design of the first aspect, the method further includes: the access and mobility management function receives a first message from a first access network device, wherein the first message comprises a registration request of a terminal device, the registration request is used for requesting to register to a first communication system, the registration request comprises mobility information, and the mobility information indicates that the terminal device comes from a second communication system; the access and mobility management function instructs the first access network device to initiate an intra-system handover or release procedure, including: and the access and mobility management function instructs the first access network equipment to initiate an intra-system handover or release process according to the mobility information.

In the above technical solution, the access and mobility management function may perform access control on the terminal device during the registration process of the terminal device. Specifically, the access and mobility management function may learn, according to mobility information in the registration request of the terminal device, that the terminal device is switched from the second communication system to the first communication system, and further instruct the first access network device to initiate an intra-system handover or release procedure when the switched first access network device does not support the CAG subscription of the terminal device.

In a possible design of the first aspect, the first message includes cell CAG capability information of the first access network device.

In a possible design of the first aspect, the instructing, by the access and mobility management function, the first access network device to initiate an intra-system handover or release procedure according to the mobility information includes: and the access and mobility management function sends a second message to the first access network equipment according to the mobility information, wherein the second message is used for indicating or requesting to perform intra-system switching or release on the terminal equipment, and the second message comprises the CAG subscription of the terminal equipment.

In a possible design of the first aspect, the second message includes a cause value, and the cause value is used to indicate that CAG subscription of the terminal device is not supported.

In a possible design of the first aspect, the instructing, by the access and mobility management function, the first access network device to initiate an intra-system handover or release procedure according to the mobility information includes: and the access and mobility management function sends a third message to the first access network device according to the mobility information, wherein the third message comprises registration acceptance and CAG subscription of the terminal device, and the registration acceptance is used for indicating to accept the registration request of the terminal device.

In one possible design of the first aspect, the method further includes: the access and mobility management function receives a forwarding redirection request from a mobility management entity, wherein the forwarding redirection request is used for requesting to redirect the terminal equipment to the access and mobility management function; the access and mobility management function sends a switching request to the first access network device, wherein the switching request is used for requesting to switch the terminal device to the first access network device, and the switching request comprises a CAG subscription of the terminal device; the access and mobility management function receives a switching request response from first access network equipment, wherein the switching request response is used for indicating to accept the switching request, the switching request response comprises first indication information, and the first indication information is used for indicating that terminal equipment needs to be switched or released in a system subsequently; and the access and mobility management function indicates the first access network equipment to initiate an intra-system handover or release process according to the first indication information.

In the above technical solution, in the process of switching the terminal device from the second communication system to the first access network device of the first communication system, if the first access network device does not support the CAG subscription of the terminal device, the first access network device may still receive the switching request, but the access and mobility management function is notified that the terminal device needs to perform intra-system switching or release subsequently by carrying the first indication information in the switching request response. In this way, the access and mobility management function may perform access control on the terminal device according to the first indication information in a registration process of the terminal device after the handover is completed.

In a possible design of the first aspect, the handover request includes handover type information indicating handover from the second communication system to the first communication system.

In a possible design of the first aspect, accessing a CAG subscription with a mobility management function of a terminal device includes: and if the access and mobility management function judges that the terminal equipment has an ongoing session associated with PNI-NPN information or the use type of the terminal equipment is a specific use type, acquiring a CAG subscription of the terminal equipment from unified data management, wherein the PNI-NPN information comprises specific S-NSSAI and/or DNN.

In one possible design of the first aspect, the method further includes: the access and mobility management function receives a fourth message from the first access network device, wherein the fourth message is used for notifying the access and mobility management function that the terminal device is switched, or the fourth message comprises a registration request of the terminal device, and the registration request is used for requesting to register to the first communication system; the access and mobility management function instructs the first access network device to initiate an intra-system handover or release procedure according to the first indication information, including: and the access and mobility management function sends a fifth message to the first access network device according to the first indication information, wherein the fifth message is used for indicating or requesting to perform intra-system handover or release on the terminal device, and the fifth message comprises a cause value which is used for indicating that the CAG subscription of the terminal device is not supported.

In a possible design of the first aspect, the fifth message includes cell CAG capability information of the first access network device.

In one possible design of the first aspect, the method further includes: and the access and mobility management function receives a sixth message from the first access network device, where the sixth message is used to notify the access and mobility management function of waiting for the subsequent triggering of the intra-system handover procedure by the first access network device, or used to notify the access and mobility management function of triggering the release procedure or waiting for the triggering of the release procedure by the first access network device.

In one possible design of the first aspect, the method further includes: the access and mobility management function sends a seventh message to the first access network device; if the sixth message is used to notify the access and mobility management function to wait for the subsequent first access network device to trigger the intra-system handover procedure, the seventh message includes a registration acceptance, and the registration acceptance is used to indicate to accept the registration request of the terminal device; if the sixth message is used to notify the access and mobility management function to trigger the release procedure or wait for the first access network device to trigger the access network release procedure, the seventh message includes a registration rejection, and the registration rejection is used to indicate to reject the registration request of the terminal device.

In a second aspect, embodiments of the present application provide a cross-system handover method, which may be performed by a first access network device, or may be performed by a component (e.g., a chip or a circuit) configured in the first access network device.

The method comprises the following steps: a first access network device of a first communication system receives an indication from an access and mobility management function, the first access network device does not support CAG subscription of a terminal device, and the terminal device is switched to the first access network device from a second communication system; and the first access network equipment initiates an intra-system switching or releasing process according to the indication.

In a possible design of the second aspect, the CAG subscription of the terminal device is used to indicate an identity of one or more CAGs allowed by the terminal device and/or whether the terminal device is only allowed to access the first communication system through a CAG cell.

In one possible design of the second aspect, the method further includes: the first access network equipment sends cell CAG capability information to an access and mobility management function, wherein the cell CAG capability information is used for indicating whether a cell of the first access network equipment supports a CAG function, and if the cell CAG capability information supports the CAG function, the cell CAG capability information is also used for indicating one or more CAG identifiers supported by the cell.

In a possible design of the second aspect, the first access network device does not support CAG subscription of the terminal device, and includes: a cell of first access network equipment supports a CAG function, but the identification of one or more CAGs supported by the cell is not the identification of a CAG allowed by terminal equipment; or, the cell of the first access network device does not support the CAG function, but the terminal device only allows access to the first communication system through the CAG cell.

In one possible design of the second aspect, the method further includes: the first access network equipment sends a first message to an access and mobility management function, wherein the first message comprises a registration request of the terminal equipment, the registration request is used for requesting to register to the first communication system, and the registration request comprises mobility information which indicates that the terminal equipment comes from the second communication system.

In a possible design of the second aspect, the first message includes cell CAG capability information of the first access network device.

In one possible design of the second aspect, the first access network device receives an indication from an access and mobility management function, including: the first access network equipment receives a second message from the access and mobility management function, the second message is used for indicating or requesting to perform intra-system handover or release on the terminal equipment, and the second message comprises CAG subscription of the terminal equipment.

In a possible design of the second aspect, the second message includes a cause value, and the cause value is used to indicate that CAG subscription of the terminal device is not supported.

In one possible design of the second aspect, the first access network device receives an indication from an access and mobility management function, including: and the first access network equipment receives a third message from the access and mobility management function, wherein the third message comprises registration acceptance and CAG subscription of the terminal equipment, and the registration acceptance is used for indicating to accept the registration request of the terminal equipment.

In one possible design of the second aspect, the method further includes: the method comprises the steps that a first access network device receives a switching request from an access and mobility management function, the switching request is used for requesting to switch a terminal device to the first access network device, and the switching request comprises a CAG subscription of the terminal device; and if the first access network equipment judges that the CAG subscription of the terminal equipment is not supported, sending a switching request response to the access and mobility management function, wherein the switching request response is used for indicating to receive the switching request, the switching request response comprises first indication information, and the first indication information is used for indicating that the terminal equipment needs to be switched or released in a system subsequently.

In one possible design of the second aspect, the handover request includes handover type information indicating handover from the second communication system to the first communication system; the first access network equipment sends a switching request response to the access and mobility management function, and the switching request response comprises the following steps: and the first access network equipment sends a switching request response to the access and mobility management function according to the switching type information.

In one possible design of the second aspect, the method further includes: the first access network equipment sends a fourth message to the access and mobility management function, wherein the fourth message is used for informing the access and mobility management function that the terminal equipment is switched, or the fourth message comprises a registration request of the terminal equipment, and the registration request is used for requesting to register to the first communication system; the first access network device receiving an indication from an access and mobility management function, comprising: the first access network device receives a fifth message from the access and mobility management function, the fifth message is used for indicating or requesting intra-system handover or release of the terminal device, the fifth message includes a cause value, and the cause value is used for indicating that the CAG subscription of the terminal device is not supported.

In a possible design of the second aspect, the fourth message includes cell CAG capability information of the first access network device.

In one possible design of the second aspect, the method further includes: the first access network device sends a sixth message to the access and mobility management function, where the sixth message is used to notify the access and mobility management function to wait for the subsequent first access network device to trigger an intra-system handover procedure, or to notify the access and mobility management function to trigger a release procedure or wait for the first access network device to trigger a release procedure.

In one possible design of the second aspect, the method further includes: the first access network equipment receives a seventh message from the access and mobility management function; if the sixth message is used for notifying the access and mobility management function to wait for the subsequent first access network equipment to trigger the switching process in the system, the seventh message comprises registration acceptance which is used for indicating to accept the registration request of the terminal equipment; if the sixth message is used to notify the access and mobility management function to trigger the release procedure or wait for the first access network device to trigger the release procedure, the seventh message includes a registration rejection, and the registration rejection is used to indicate to reject the registration request of the terminal device.

In a possible design of the second aspect, the initiating, by the first access network device, an intra-system handover procedure or a release procedure includes: and the first access network equipment signs a contract according to the CAG of the terminal equipment, if second access network equipment supporting the CAG sign is found, the switching process in the system is initiated, and if not, the releasing process is initiated.

The beneficial effects in any possible design of the second aspect may refer to the corresponding descriptions in the first aspect, and are not described again.

In a third aspect, embodiments of the present application provide a cross-system handover method, which may be performed by a first access network device, or may be performed by a component (e.g., a chip or a circuit) configured in the first access network device.

The method comprises the following steps: a first access network device of a first communication system receives a switching request from an access and mobility management function, wherein the switching request is used for requesting to switch a terminal device to the first access network device, and the switching request comprises a CAG (computer aided generation) subscription of the terminal device; if the first access network equipment does not support CAG subscription of the terminal equipment, the first access network equipment sends a switching request response to the access and mobility management function, wherein the switching request response is used for indicating to receive the switching request, the switching request response comprises first indication information, and the first indication information is used for indicating that the terminal equipment needs to perform intra-system switching or release subsequently; and the first access network equipment initiates an intra-system switching or releasing process according to the first indication information.

In the above technical solution, for a terminal device that is switched from a second communication system to a first communication system, in a switching process of the terminal device, if the first access network device does not support a CAG subscription of the terminal device, the first access network device may still receive a switching request, but notifies an access and mobility management function that the terminal device needs to perform intra-system switching or release subsequently by carrying first indication information in a switching request response, and the first access network device actively initiates an intra-system switching or release procedure, so as to switch the terminal device to a cell under an access network device that supports the CAG subscription in the first communication system, thereby avoiding a switching or access failure and improving a success rate of cross-system switching.

In a possible design of the third aspect, the handover request includes handover type information indicating handover from the second communication system to the first communication system; the first access network equipment sends a switching request response to the access and mobility management function, and the switching request response comprises the following steps: and the first access network equipment sends a switching request response to the access and mobility management function according to the switching type information.

In a possible design of the third aspect, before the initiating, by the first access network device, an intra-system handover or release procedure, the method further includes: the first access network equipment sends a fifth message to the access and mobility management function; the fifth message is used for notifying the completion of the switching of the access and mobility management function terminal equipment, or the fifth message includes a registration request of the terminal equipment, and the registration request is used for requesting to register to the first communication system.

In the above technical solution, the first access network device may actively initiate an intra-system handover or release procedure according to the first indication information when the handover of the terminal device is completed or the registration process is started.

In a possible design of the third aspect, the initiating, by the first access network device, an intra-system handover procedure or a release procedure includes: and the first access network equipment signs according to the CAG of the terminal equipment, if second access network equipment supporting the CAG signing is found, an intra-system switching process is initiated, and if not, a releasing process is initiated.

In a fourth aspect, embodiments of the present application provide a cross-system handover method, which may be performed by an access and mobility management function, or may be performed by a component (e.g., a chip or a circuit) configured for the access and mobility management function.

The method comprises the following steps: an access and mobility management function of a first communication system receives a forwarding redirection request from a mobility management entity, wherein the forwarding redirection request is used for requesting to redirect terminal equipment to the access and mobility management function; accessing and acquiring a CAG subscription of the terminal equipment by a mobile management function; the access and mobility management function sends a switching request to the first access network device, wherein the switching request is used for requesting to switch the terminal device to the first access network device, and the switching request comprises a CAG subscription of the terminal device; the access and mobility management function receives a handover request response from a first access network device, where the handover request response is used to indicate that the handover request is accepted, the handover request response includes first indication information, the first indication information is used to indicate that the terminal device needs to perform intra-system handover or release subsequently, and the first access network device does not support CAG subscription of the terminal device.

In a possible design of the fourth aspect, the acquiring, by the access and mobility management function, a closed access group CAG subscription of the terminal device includes: and the access and mobility management function judges that the terminal equipment has an ongoing session associated with PNI-NPN information or the use type of the terminal equipment is a specific use type, and acquires the CAG subscription of the terminal equipment from unified data management, wherein the PNI-NPN information comprises specific S-NSSAI and/or DNN.

In one possible design of the fourth aspect, the handover request includes handover type information indicating handover from the second communication system to the first communication system.

In one possible design of the fourth aspect, the method further includes: the access and mobility management function receives a fifth message from the first access network device; the fifth message is used for notifying the completion of the switching of the access and mobility management function terminal equipment, or the fifth message includes a registration request of the terminal equipment, and the registration request is used for requesting to register to the first communication system.

The beneficial effects in any possible design of the fourth aspect may refer to the corresponding descriptions in the third aspect, and are not described again.

In a fifth aspect, the present embodiments provide a communication apparatus, which may have a function of implementing the access and mobility management functions in any possible design of the above aspects or aspects, or a function of implementing the first access network device in any possible design of the above aspects or aspects. The device may be a network device, or may be a chip included in the network device.

The functions of the communication device may be implemented by hardware, or by hardware executing corresponding software, which includes one or more modules or units or means (means) corresponding to the functions.

In one possible design, the apparatus includes a processing module and a transceiver module in a structure, wherein the processing module is configured to support the apparatus to perform a function corresponding to a mobility management function in any one of the aspects or aspects described above, or to perform a function corresponding to the first access network device in any one of the aspects or aspects described above. The transceiver module is configured to support communication between the apparatus and other communication devices, for example, when the apparatus is an access and mobility management function, the transceiver module may receive a registration request from a terminal device of the first access network device. The communication device may also include a memory module, coupled to the processing module, that retains the necessary program instructions and data for the device. As an example, the processing module may be a processor, the communication module may be a transceiver, the storage module may be a memory, and the memory may be integrated with the processor or provided separately from the processor.

In another possible design, the apparatus may be configured to include a processor and may also include a memory. A processor is coupled to the memory and is operable to execute the computer program instructions stored in the memory to cause the apparatus to perform the methods of any of the possible designs of the above-described aspects or aspects. Optionally, the apparatus further comprises a communication interface, the processor being coupled to the communication interface. When the apparatus is a network device, the communication interface may be a transceiver or an input/output interface; when the apparatus is a chip included in a network device, the communication interface may be an input/output interface of the chip. Alternatively, the transceiver may be a transceiver circuit and the input/output interface may be an input/output circuit.

In a sixth aspect, an embodiment of the present application provides a chip system, including: a processor coupled to a memory for storing a program or instructions that, when executed by the processor, cause the system-on-chip to implement the method in any one of the possible designs of the above-described aspects or aspects.

Optionally, the system-on-chip further comprises an interface circuit for interfacing code instructions to the processor.

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

Optionally, the memory in the system-on-chip may also be one or more. The memory may be integral to the processor or may be separate from the processor. Illustratively, the memory may be a non-transitory processor, such as a read only memory ROM, which may be integrated on the same chip as the processor or may be separately provided on different chips.

In a seventh aspect, embodiments of the present application provide a computer-readable storage medium having stored thereon a computer program or instructions, which when executed, cause a computer to perform the method in any one of the possible designs of the above-mentioned aspects or aspects.

In an eighth aspect, embodiments of the present application provide a computer program product which, when read and executed by a computer, causes the computer to perform the method in any one of the possible designs of the above-described aspect or aspects.

In a ninth aspect, an embodiment of the present application provides a communication system, which includes an access and mobility management function and a first access network device. The access and mobility management function and the first access network device belong to a first communication system. Optionally, the communication system further includes a second access network device, and the second access network device also belongs to the first communication system.

In one possible design, the communication system further includes a mobility management entity and a third access network device, where the mobility management entity and the third access network device belong to the second communication system.

Illustratively, the first communication system is a fifth generation communication system 5GS and the second communication system is a packet evolution system EPS. The first access network device and the second access network device may be a next generation radio access network node/base station NG-RAN in a fifth generation communication system 5GS and the third access network device may be an evolved universal terrestrial radio access network node/base station E-UTRAN in a packet evolution system EPS.

These and other aspects of the present application will be more readily apparent from the following description of the embodiments.

Drawings

Fig. 1 is a schematic diagram of a network architecture of a communication system to which the present application is applicable;

fig. 2 is a schematic diagram of a network architecture of a 5G communication system suitable for the present application;

fig. 3 is a schematic diagram of a network architecture of a joint deployment of a 4G communication system and a 5G communication system, which is applicable to the present application;

fig. 4 is a flowchart illustrating an access control method according to an embodiment of the present application;

fig. 5 is a schematic diagram illustrating a process of acquiring a CAG subscription of a terminal device by an AMF in an embodiment of the present application;

FIG. 6 is a diagram illustrating a related process I according to an embodiment of the present application;

fig. 7, fig. 8 and fig. 9 are several specific examples of the above related procedure one;

FIG. 10 is a diagram illustrating a second related procedure in an embodiment of the present application;

fig. 11 is a specific example of the above related flow chart ii;

fig. 12 is a flowchart illustrating another access control method according to an embodiment of the present application;

fig. 13 is a flowchart illustrating another access control method according to an embodiment of the present application;

fig. 14 is a flowchart illustrating another access control method according to an embodiment of the present application;

fig. 15 is a flowchart illustrating another access control method according to an embodiment of the present application;

fig. 16, fig. 17, or fig. 18 are schematic structural diagrams of a communication device according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in further detail with reference to the accompanying drawings.

The technical solution of the embodiment of the present application may be applied to various communication systems, for example, a Long Term Evolution (LTE) system, a Frequency Division Duplex (FDD) system, a LTE Time Division Duplex (TDD) system, a fifth generation (5th generation, 5G) mobile communication system or a New Radio (NR) system, or may be applied to a future communication system or other similar communication systems.

Please refer to fig. 1, which is a schematic diagram of a network architecture of a communication system applicable to the present application. The network architecture includes four components, which are a terminal device (UE), AN Access Network (AN), a Core network (Core), and a Data Network (DN), respectively, where the access network may be a Radio Access Network (RAN).

The terminal device, the (radio) access network and the core network are the main parts of the network architecture, and logically, they can be divided into two parts, namely a user plane and a control plane, wherein the control plane is responsible for the management of the mobile network, and the user plane is responsible for the transmission of service data. Illustratively, as shown in fig. 1, in a 5G communication system, the next generation (NextGen, NG)2 reference point is located between the (radio) access network control plane and the core network control plane, the NG3 reference point is located between the (radio) access network user plane and the core network user plane, and the NG6 reference point is located between the core network user plane and the data network.

The components of the network architecture described above are described in detail below.

1. The terminal device is a device with wireless transceiving function, is an entrance for interaction between a mobile user and a network, and can provide basic computing capability and storage capability, display a service window for the user and receive operation input of the user. The terminal device may communicate with a core network or a data network via a (radio) access network, exchanging voice and/or data with the (radio) access network. Illustratively, in a 5G communication system, the next generation terminal equipment (NextGen UE, NG UE) may employ New Radio (NR) technology to establish signal and data connections with a (wireless) access network to transmit control signals and traffic data to the network.

Illustratively, the terminal device may include a wireless terminal device, a mobile terminal device, a device-to-device (D2D) terminal device, a vehicle networking (V2X) terminal device, a machine-to-machine/machine-type communication (M2M/MTC) terminal device, an internet of things (IoT) terminal device, a subscriber unit (subscriber unit), a subscriber station (subscriber state), a mobile station (mobile state), a remote station (remote state), an access point (access point, AP), a remote terminal (remote terminal), an access terminal (access terminal), a user terminal (user terminal), a user agent (user agent), or a user equipment (user device), etc. For example, the terminal device may be a mobile phone (mobile phone), a tablet computer (Pad), a computer with wireless transceiving function, a portable, pocket, handheld, computer-embedded mobile device, and the like. Also for example, the terminal device may be a Virtual Reality (VR) terminal device, an Augmented Reality (AR) terminal device, a wireless terminal in industrial control (industrial control), a wireless terminal in self driving (self driving), a wireless terminal in remote surgery (remote medical supply), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), a terminal device in future evolution Public Land Mobile Network (PLMN), or a CPE vehicle device in V2X, a customer premise equipment (customer equipment), or the like. For another example, the terminal device may be a Personal Communication Service (PCS) phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), and the like.

By way of example, and not limitation, the terminal device may also be a wearable device. Wearable equipment can also be called wearable smart device or intelligent wearable equipment etc. is the general term of using wearable technique to carry out intelligent design, develop the equipment that can dress to daily wearing, like glasses, gloves, wrist-watch, dress and shoes etc.. The wearable device may be worn directly on the body or may be a portable device integrated into the user's clothing or accessory. The wearable device is not only a hardware device, but also realizes powerful functions through software support, data interaction and cloud interaction. The generalized wearable smart device includes full functionality, large size, and can implement full or partial functionality without relying on a smart phone, such as: smart watches or smart glasses and the like, and only focus on a certain type of application functions, and need to be used in cooperation with other devices such as smart phones, such as various smart bracelets, smart helmets, smart jewelry and the like for monitoring physical signs. The various terminal devices described above, if located on a vehicle (e.g., placed in or installed in the vehicle), may be considered to be vehicle-mounted terminal devices, which are also referred to as on-board units (OBUs), for example.

The terminal equipment can be deployed on land, including indoor or outdoor, handheld, wearable or vehicle-mounted; can also be deployed on the water surface (such as a ship and the like); and may also be deployed in the air (e.g., airplanes, balloons, satellites, etc.). The embodiment of the present application does not limit the specific technology, device form, application scenario, and name used by the terminal device.

2. The (wireless) access network is deployed at a position close to the terminal equipment, provides a network access function for authorized users in a specific area, and can determine transmission tunnels with different qualities according to the grade of the users, the service requirements and the like to transmit user data. The (radio) access network is able to manage and reasonably utilize its own resources, provide access services to the terminal devices as required, and is responsible for forwarding control signals and traffic data between the terminal devices and the core network.

A (radio) access network device is deployed in the (radio) access network for accessing the terminal device to the radio network. The (radio) access network devices may typically be connected to the core network by a wired link, e.g. a fibre optic cable. The (radio) access network device may also be referred to as RAN device/node, or base station.

Exemplarily, the (wireless) access network device may include a base station, an evolved NodeB (eNodeB) in an LTE system or an evolved LTE system (LTE-Advanced, LTE-a), a next generation NodeB (gNB) in a 5G communication system, a Transmission Reception Point (TRP), a baseband unit (BBU), an Access Point (AP) in a Wireless Local Area Network (WLAN), an access backhaul and backhaul (IAB) node, a base station in a future mobile communication system or an access node in a WiFi system, and the like. The radio access network device may also be a module or unit, such as a Centralized Unit (CU) or a Distributed Unit (DU), which performs part of the functions of the base station.

For example, in one network configuration, the (radio) access network device may be a CU node, or a DU node, or a (radio) access network device comprising a CU node and a DU node. The CU node is configured to support Radio Resource Control (RRC), Packet Data Convergence Protocol (PDCP), Service Data Adaptation Protocol (SDAP), and other protocols; the DU node is configured to support a Radio Link Control (RLC) layer protocol, a Medium Access Control (MAC) layer protocol, and a physical layer protocol.

The (wireless) access network devices may be deployed on land, including indoors or outdoors, hand-held, worn, or vehicle-mounted; can also be deployed on the water surface (such as a ship and the like); and may also be deployed in the air (e.g., airplanes, balloons, satellites, etc.). The embodiments of the present application do not limit the specific technologies, device forms, application scenarios, and names used by the (wireless) access network devices. In the embodiment of the present application, the (wireless) access network device may be referred to as AN Access Network (AN) device for short, and the access network devices in the following may be (wireless) access network devices unless otherwise specified.

3. And the core network is responsible for maintaining subscription data of the mobile network, managing network elements of the mobile network, and providing functions of session management, mobility management, policy management, security authentication and the like for the terminal equipment. The method specifically comprises the following steps: when the terminal equipment is attached, providing network access authentication for the terminal equipment; when the terminal equipment has a service request, network resources are distributed to the terminal equipment; updating network resources for the terminal equipment when the terminal equipment moves; when the terminal equipment is idle, a quick recovery mechanism is provided for the terminal equipment; when the terminal equipment is detached, releasing network resources for the terminal equipment; when the terminal device has service data, it is provided with a data routing function, such as forwarding uplink data to the data network, or receiving downlink data from the data network and forwarding to the (radio) access network, so as to send to the terminal device.

4. And the data network is used for providing service for the user. In an actual communication process, the client is usually located in a terminal device, and the server is usually located in a data network. The data network may be a private network, such as a local area network, an external network that is not controlled by an operator, such as the Internet (Internet), or a private network that is deployed by an operator, such as a network that provides an IP multimedia network subsystem (IMS) service.

Fig. 2 shows a more specific network architecture to which the embodiment of the present application is applicable, which may be a network architecture of a 5G communication system. As shown in fig. 2, the network architecture includes a terminal device, an access network device, various types of core network elements/functional entities, and a data network.

The core network user plane includes a User Plane Function (UPF). The core network control plane includes, but is not limited to: access and mobility management function (AMF), Session Management Function (SMF), authentication server function (AUSF), Network Slice Selection Function (NSSF), network open function (NEF), network function repository function (NRF), Policy Control Function (PCF), Unified Data Management (UDM), Application Function (AF).

Specifically, the AMF is mainly responsible for access management and mobility management of the terminal device, for example, is responsible for state maintenance of the terminal device, reachability management of the terminal device, forwarding of a non-mobility management non-access-stratum (MM NAS) message, and forwarding of a Session Management (SM) N2 message.

The SMF is mainly responsible for session management in the mobile network, including establishing a session for a terminal device, allocating and releasing resources for the session, where the resources include quality of service (QoS) of the session, session route, forwarding rules, and the like. For example, an Internet Protocol (IP) address is allocated to the terminal device, and a UPF providing a message forwarding function is selected.

The UPF is mainly responsible for connecting external networks, and performs user packet forwarding according to the routing rule of the SMF, for example, uplink data is sent to a data network or other UPFs, and downlink data is sent to other UPFs or access network devices.

The AUSF is mainly responsible for performing security authentication of the terminal device.

The NSSF is mainly responsible for selecting an appropriate network slice for the traffic of the terminal.

The NEF exposes part of the functionality of the network to applications in a controlled manner.

The NRF is mainly responsible for providing a storage function and a selection function of network function entity information for other network elements.

The PCF is mainly responsible for user policy management, including policy authorization, service quality and charging rule generation, and issues the corresponding rule to the UPF through the SMF, and completes the installation of the corresponding policy and rule.

The UDM is mainly responsible for managing user data including subscription information, context, policy information, etc. It should be noted that although not temporarily shown in fig. 2, a Unified Data Repository (UDR) may also be included in the network architecture shown in fig. 2, and the functions of the UDM may be implemented through interaction with the UDR. The UDR is used for storing data required by the UDM when executing its operation, and the UDM is used for interacting with other network elements. In practical implementation, the UDM and the UDR may be two separate physical entities, and the UDR may also be integrated in the UDM, without limitation.

The AF is mainly responsible for providing service data of various applications to a control plane network element of a communication network of an operator, or obtaining data information and control information of the network from the control plane network element of the communication network.

As an example, in the network architecture shown in fig. 2, an interface between the terminal device and the AMF is referred to as an N1 interface, an interface between the access network device and the AMF is referred to as an N2 interface, an interface between the access network device and the UPF is referred to as an N3 interface, an interface between the UPF and the SMF may be referred to as an N4 interface, and an interface between the UPF and the data network is referred to as an N6 interface. Of course, in future communication systems, the names of these interfaces may be unchanged or replaced by other names, which is not limited in this application.

It should be noted that the core network control plane may adopt a service architecture, each control plane network element is connected to one service bus, and the interaction between the control plane network elements adopts a service invocation mode to replace a point-to-point communication mode in the conventional core network architecture. In the service architecture, the control plane network element opens service to other control plane network elements for the other control plane network elements to call. In point-to-point communication, a communication interface between control plane network elements has a set of specific messages, and the control plane network elements at two ends of the interface can only use the messages during communication.

The embodiment of the application can also be applied to the scene of joint deployment of various communication systems. Illustratively, fig. 3 shows another possible network architecture to which the embodiment of the present application is applicable, in which a 4G communication system and a 5G communication system coexist and interwork. The 4G communication system may be an Evolved Packet System (EPS), and the 5G communication system may be referred to as a 5GS for short.

As shown in fig. 3, the EPS part includes the following network elements:

1. and the access network equipment is used for providing a network access function for the authorized terminal equipment in a specific area, and can use transmission tunnels with different qualities according to the grade of the terminal equipment, the service requirement and the like. In EPS, the access network equipment may be referred to as evolved universal terrestrial radio access network (E-UTRAN) or evolved base station (eNB). In one possible design, the E-UTRAN may communicate with the UE over an air interface.

2. A Mobility Management Entity (MME) for providing mobility management functions. In addition, the MME may also provide functions such as lawful interception and access authorization/authentication. In one possible design, the MME may communicate with the E-UTRAN through an S1-MME interface.

3. A Serving Gateway (SGW) is used for providing functions such as user data forwarding. In one possible design, the SGW may communicate with the E-UTRAN via an S1-U interface, with a packet data network gateway user plane function (PGW-U) via an S5-U interface, and with a packet data network gateway control plane function (PGW-C) via an S5-C interface.

4. And the PGW-U is used for providing the user plane function of the PDN gateway.

5. And the PGW-C is used for providing a control plane function of the PDN gateway.

6. A Home Subscriber Server (HSS) for storing subscriber profiles, performing authentication and authorization of subscribers, and providing information about the physical location of subscribers. In one possible design, the HSS may communicate with the MME over an S6a interface and with the PGW-C over an N10 interface.

The 5GS part comprises the following network elements/functional entities:

1. and the access network equipment is used for providing a network access function for authorized terminal equipment in a specific area and can use transmission tunnels with different qualities according to the grade, service requirements and the like of the terminal equipment. In 5GS, the access network device may be referred to as a next generation radio access network (NG-RAN) or a next generation base station (gNB). In one possible design, the NG-RAN may communicate with the UE over an air interface.

2. AMF for access management and mobility management functions. In addition, the AMF may also provide functions such as lawful interception and access authorization/authentication. In one possible design, the AMF may communicate with the MME over an N26 interface.

3. UPF is used for functions such as packet routing and forwarding, QoS management of user plane data and the like. In one possible design, the UPF may communicate with the NG-RAN over an N3 interface.

4. The SMF is mainly used for session management, IP address allocation and management of terminal equipment and selection and management of UPF. The SMF may also be a termination point of the policy control and charging function interface. In one possible design, the SMF may communicate with the AMF over an N11 interface.

5. The PCF, a unified policy framework for guiding network behavior, provides policy rule information for control plane function network elements (e.g., AMF, SMF, etc.), and so on. In one possible design, the PCF may communicate with the AMF over an N15 interface.

6. And the UDM is used for managing user subscription data. In addition, the method is also used for user service registration management, terminal equipment identification processing, access authentication and the like. In one possible design, the UDM may communicate with the AMF over an N8 interface.

In the above network architecture, network elements with the same or similar functions may be jointly configured. For example, the UPF and PGW-U may be combined, the SMF and PGW-C may be combined, the HSS and UDM may be combined, and the "+" in fig. 3 indicates that two devices may be combined.

It can be understood that, in the network architecture shown in fig. 3, the terminal device may attach to the EPS and perform cell handover inside the EPS; similarly, the terminal device may attach in 5GS and perform cell handover inside 5G S; possibly, the terminal device may also perform a cross-system cell handover, such as a cross-system handover from the EPS to the 5GS, or a cross-system handover from the 5GS to the EPS. The cross-system handover may also be referred to as a cross-communication indication or a cross Radio Access Technology (RAT) handover.

It should be noted that the network elements/functional entities in the various possible network architectures described above may be network elements in hardware devices, or may be software functions running on dedicated hardware, or may be virtualized functions instantiated on a platform (e.g., a cloud platform). Optionally, the network element or the functional entity may be implemented by one device, or may be implemented by multiple devices together, or may be different functional modules in one device, which is not specifically limited in this embodiment of the present application.

The network architecture and the service scenario described in the embodiment of the present application are for more clearly illustrating the technical solution in the embodiment of the present application, and do not form a limitation on the technical solution provided in the embodiment of the present application, and it can be known by a person of ordinary skill in the art that the technical solution provided in the embodiment of the present application is also applicable to similar technical problems with the evolution of the architecture of the communication system and the occurrence of a new service scenario.

The terms "system" and "network" in the embodiments of the present application may be used interchangeably. The "plurality" means two or more, and in view of this, the "plurality" may also be understood as "at least two" in the embodiments of the present application. "at least one" is to be understood as meaning one or more, for example one, two or more. For example, the inclusion of at least one means that one, two or more are included, and does not limit which is included. For example, at least one of A, B and C is included, then inclusion can be A, B, C, A and B, A and C, B and C, or A and B and C. Similarly, the understanding of the description of "at least one" and the like is similar. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single item(s) or plural items. For example, "at least one of A, B, and C" includes A, B, C, AB, AC, BC, or ABC. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" generally indicates that the preceding and following related objects are in an "or" relationship, unless otherwise specified.

Unless specifically stated otherwise, the embodiments of the present application refer to the ordinal numbers "first", "second", etc., for distinguishing between a plurality of objects, and do not limit the sequence, timing, priority, or importance of the plurality of objects, and the descriptions of "first", "second", etc., do not limit the objects to be necessarily different.

Some technical features related to the embodiments of the present application are explained below. It should be noted that these explanations are for the purpose of making the examples of the present application easier to understand, and should not be construed as limiting the scope of protection claimed in the present application.

1. CAG: since only authorized terminal devices are usually provided with NPN services, a CAG function may be introduced to avoid unauthorized terminal devices accessing and selecting NPN. For example, an authorized terminal device may be configured with an allowed CAG in advance, and the terminal device allowed CAG may be understood as a CAG to which the terminal device is allowed to access or a CAG to which the terminal device belongs. In this way, the NPN service is provided to the terminal device belonging to a certain CAG or to certain CAGs according to the CAGs allowed by the terminal device. From the perspective of a CAG, a CAG may include one or more terminal devices; from the perspective of the terminal device, one terminal device may belong to one or more CAGs. The identification of the CAG is used to identify the CAG.

2. CAG cell (cell): cells that support CAG functionality are referred to as CAG cells. From a cell perspective, one cell may support one or more CAGs. A CAG cell may broadcast the identity of one or more CAGs it supports, and further, may broadcast PLMN information. A CAG cell may also be understood as a cell associated with a CAG. From the perspective of CAG, one CAG may be associated with one or more cells. As such, the one or more CAGs supported by a CAG cell may also be referred to as the one or more CAGs associated with the CAG cell

Correspondingly, a cell that does not support the CAG function is referred to as a non- (non) CAG cell. A non-CAG cell may also be understood as a cell that does not support any CAG or a cell that is not associated with any CAG.

3. Cell CAG capability information: in 5GS, there may be multiple cells under the access network device, and each cell may have corresponding cell CAG capability information. The cell CAG capability information of a cell is used to indicate whether the cell supports a CAG function, if the cell supports the CAG function, the cell is a CAG cell, and the cell CAG capability information may further indicate an identifier of one or more CAGs supported (or broadcasted) by the cell. And if the CAG function is not supported, the cell is a non-CAG cell. Illustratively, the cell CAG capability information may include CAG capability indication information and a list of supported CAGs (list) of the cell. The CAG capability indication information of the cell may be a flag bit of 1 bit. When the flag bit is 1, it indicates that the cell supports the CAG function, and further, the supported CAG list may include an identifier of one or more CAGs supported (or broadcasted) by the cell; when the flag bit is 0, it may indicate that the cell does not support the CAG function.

4. Network Slice Selection Assistance Information (NSSAI): a set of auxiliary information (S-NSSAI) or a list of S-NSSAIs is selected for a single network slice, i.e., one or more S-NSSAIs may be included in an NSSAI. For example, an S-NSSAI may be used to identify a network slice (or the network slice may be identified by an S-NSSAI), and accordingly, an NSSAI may be a set or list of network slice identifications.

Among these, NSSAI may include a variety of, such as: firstly, signing NSSAI (subscribed NSSAI), namely NSSAI subscribed by the terminal equipment, belongs to signing information of the terminal equipment; requesting NSSAI (requested NSSAI), namely one or more S-NSSAIs carried in a request message sent by the terminal equipment during registration; allowing NSSAI (allowed NSSAI), that is, one or more S-NSSAIs allowed to be used by the terminal device by the network in the NSSAI requested by the terminal device, and the network may return a registration response to the terminal device; configuring NSSAI (configured NSSAI), wherein the NSSAI used by the network for the terminal equipment can be returned to the terminal equipment through a registration response, so that the terminal equipment can know which S-NSSAI is available according to the configured NSSAI, and if the configuration of the terminal equipment is changed after registration, the network can inform the terminal equipment to update the configured NSSAI; the terminal device may save the configuration NSSAI configured for it by each network in a non-volatile memory space.

5. CAG subscription of the terminal equipment: the CAG subscription of the terminal device is a part of the mobility restriction in the PLMN subscription data of the terminal device, and is intended to control the terminal device to access the PNI-NPN based on the public network 5GS, for example, to control the terminal device to access the 5GS through an allowed CAG cell, or to control the terminal device to access the 5GS only through the CAG cell and not to access the 5GS through a non-CAG cell.

The CAG subscription of the terminal device is used for indicating the identifier of one or more CAGs allowed by the terminal device (or indicating the identifier of one or more CAGs to which the terminal device belongs), and whether the terminal device allows only 5GS access through a CAG cell.

For example, the CAG subscription of the terminal device may include an available CAG list and/or CAG capability indication information of the terminal device. The available CAG list of the terminal device includes identifiers of one or more CAGs allowed by the terminal device (or identifiers of one or more CAGs to which the terminal device belongs). The CAG capability indication information of the terminal device is used for indicating whether the terminal device only allows access to the 5GS through the CAG cell.

The support capability of the terminal device to the CAG in the embodiment of the application may include the following: capability is that 5GS can be accessed only through CAG cells. Capability 2, 5GS can be accessed through CAG cells, and 5GS can also be accessed through non-CAG cells.

Based on this, in an example, the CAG capability indication information of the terminal device may be a flag bit of 1 bit, and the flag bit is set to 1 or 0 to indicate that the terminal device supports the CAG capability as one of the above-mentioned capability (r) or capability (r). For example, when the flag bit is 1, it indicates that the terminal device can only access 5GS through the CAG cell; when the flag bit is 0, it indicates that the terminal device can access 5GS not only through the CAG cell, i.e., can access 5GS through the CAG cell, but also can access 5GS through a non-CAG cell.

In another example, if the CAG subscription of the terminal device does not include the CAG capability indication information of the terminal device, the terminal device may be considered to have the capability of supporting the CAG in this case, that is, 5GS may be accessed through the CAG cell or 5GS may be accessed through the non-CAG cell. In this case, it can be understood that CAG capability indication information indicating capability ·isimplicit in CAG subscription of the terminal device.

The following describes the access control method provided in the present application in detail.

For convenience of understanding, in the following embodiments, the technical solutions in the present application are described by taking AMF, SMF, UPF, UDM, PCF, and MME as examples. That is, in the following embodiments, the AMFs may be replaced by access and mobility management functions, the SMFs may be replaced by session management functions, the UPFs may be replaced by user plane functions, the UDMs may be replaced by unified data management, the PCFs may be replaced by policy control functions, and the MMEs may be replaced by mobility management entities.

Please refer to fig. 4, which is a flowchart illustrating an access control method according to an embodiment of the present disclosure, where the method is applied in a scenario where a terminal device is switched from a second communication system to a first communication system. Illustratively, the first communication system is a 5G communication system (i.e., 5GS), and the second communication system is a 4G communication system (i.e., EPS), although the first communication system and the second communication system may be other communication systems, and the present application is not limited thereto.

The method comprises the following steps:

step S401, the AMF of the first communication system obtains a CAG subscription of the terminal device, and the terminal device is switched from the second communication system to the first access network device of the first communication system.

In the embodiment of the present application, the CAG subscription of the terminal device is used to indicate one or more identifiers of CAGs allowed by the terminal device and/or whether the terminal device allows access to the first communication system only through a CAG cell. For specific content of the CAG subscription of the terminal device, please refer to the related description above, and details are not repeated here.

The access and mobility management functions may obtain a CAG subscription for the terminal device from the UDM. Optionally, the UDM may be an HSS + UDM network element in which the UDM and the HSS are co-located.

The specific acquisition process may be as shown in fig. 5: step S501, the AMF sends a first request message to the UDM to request the UDM to provide a CAG subscription of the terminal device. Optionally, the first request message may include identification information of the terminal device. Step S502, after receiving the first request message, the UDM determines the CAG subscription of the terminal device, and then carries the CAG subscription of the terminal device in the first response message and sends the first response message to the AMF. Thus, after receiving the first response message, the AMF may obtain the CAG subscription of the terminal device therein by analyzing the first response message. Illustratively, the first Request message may be a Nudm _ SDM _ Get Request message, and the first Response message may be a Nudm _ SDM _ Get Response message.

Optionally, the AMF may determine whether to acquire a CAG subscription of the terminal device according to the context of the terminal device. If the terminal device has an ongoing session associated with the PNI-NPN information or the usage type (usage type) of the terminal device is a specific usage type, the AMF may obtain a CAG subscription of the terminal device from the UDM.

Step S402, the AMF indicates the first access network equipment to initiate an intra-system switching or releasing process.

Accordingly, the first access network device receives the indication from the AMF.

In this embodiment of the application, the AMF may determine whether the first access network device supports CAG subscription of the terminal device, and if it is determined that the first access network device does not support CAG subscription of the terminal device, the AMF may instruct the first access network device to initiate an intra-system handover or release procedure in consideration that the terminal device is handed over from the second communication system to the first communication system.

Specifically, the AMF may determine whether the first access network device supports CAG subscription of the terminal device according to the cell CAG capability information of the first access network device. For example, the first access network device may send cell CAG capability information to the AMF, and the AMF determines, according to the received cell CAG capability information of the first access network device, whether the first access network device supports CAG subscription of the terminal device. Of course, the AMF may also obtain the cell CAG capability information of the first access network device in other manners, which is not limited in this application.

The cell CAG capability information is used to indicate whether the cell of the first access network device supports CAG functionality, and if so, the cell CAG capability information is also used to indicate the identifier of one or more CAGs supported (broadcasted) by the cell. For specific content of the cell CAG capability information of the first access network device, reference may be made to the related description above, and details are not repeated here.

Based on this, the first access network device supporting the CAG subscription of the terminal device may refer to: the cell of the first access network device supports the CAG function, and the identification of the one or more CAGs supported by the cell includes at least one of the identification of the one or more CAGs allowed by the terminal device. Or at least one or more identifiers of CAGs in the available CAG list of the terminal device are contained in the supported CAG list of the cell of the first access network device. Or, the cell of the first access network device does not support the CAG function, but the terminal device may access the first communication system through the CAG cell, or may access the first communication system through the non-CAG cell.

The first access network device does not support CAG subscription of the terminal device may refer to: the cell of the first access network device supports the CAG function, but the identification of one or more CAGs supported by the cell is not the identification of the CAG allowed by the terminal device; alternatively, the cell of the first access network device does not support the CAG functionality, but the terminal device only allows access to the first communication system through the CAG cell.

It should be noted that there may be one or more cells under the first access network device, and the cell indicated by the cell CAG capability information refers to the cell accessed by the terminal device in the first access network device. The cell may be a CAG cell supporting a CAG function, or may be a non-CAG cell not supporting a CAG function, and the present application is not limited thereto.

If the AMF does not receive the cell CAG capability information from the first access network device, and does not obtain the cell CAG capability information of the first access network device in other ways, the AMF may consider that the first access network device does not support the CAG subscription of the terminal device, and further instruct the first access network device to initiate an intra-system handover or release process based on the judgment and considering that the terminal device is handed over from the second communication system to the first communication system.

Optionally, the AMF may further determine whether the terminal device has an ongoing session associated with the PNI-NPN information according to the context of the terminal device. If it is determined that the first access network device does not support the CAG subscription of the terminal device and the terminal device has an ongoing session associated with the PNI-NPN information, the AMF may further instruct the first access network device to initiate an intra-system handover or release procedure in consideration of the terminal device being handed over from the second communication system to the first communication system. Wherein the PNI-NPN information includes a specific S-NSSAI and/or a Data Network Name (DNN).

And step S403, the first access network equipment initiates an intra-system switching or releasing process according to the indication.

In this embodiment, the first access network device may initiate an intra-system handover or release procedure according to the CAG subscription of the terminal device under the instruction of the AMF. Specifically, the first access network device signs a subscription according to the CAG of the terminal device, and if a second access network device supporting the CAG subscription of the terminal device in the first communication system can be found, an intra-system handover procedure can be initiated to handover the terminal device to the second access network device. If no second access network device supporting the CAG subscription of the terminal device in the first communication system is found, a release procedure may be initiated to release the connection of the terminal device. The release procedure may also be referred to as AN Access Network (AN) release procedure.

Therefore, in the embodiment of the present application, for a terminal device that is switched from a second communication system to a first communication system, the AMF may perform access control on the terminal device according to a CAG subscription of the terminal device. If the first access network device to which the terminal device is switched does not support the CAG subscription of the terminal device, the AMF may instruct the first access network device to initiate an intra-system switching or release flow so as to switch the terminal device to a cell under the access network device supporting the CAG subscription in the first communication system, thereby avoiding a switching or access failure and improving a success rate of cross-system switching.

The flow related to the above steps S401 to S403 will be described in detail below with reference to different decision manners of the AMF. It will be appreciated that the different associated flows may be different embodiments of the access control method provided in figure 4.

Related procedure one

The related procedure relates to a registration procedure after the terminal device is handed over from the second communication system to the first communication system, and the registration procedure may also be referred to as a registration update procedure or a mobility registration update procedure, which is not limited.

The AMF in the first communication system may allow the terminal device to perform handover from the second communication system to the first communication system first, and during the handover, the CAG subscription of the terminal device is not considered for the moment. After the terminal device is switched to a first access network device in a first communication system, the AMF judgment logic is enhanced in the registration process of the terminal device, so that when the first access network device to which the terminal device is currently switched does not support the CAG subscription of the terminal device, the AMF does not directly release the connection of the terminal device, but waits for or requests the first access network device to initiate an intra-system switching process, so that the terminal device is switched to a second access network device which supports the CAG subscription of the first communication system. And if the first access network equipment can not find the second access network equipment supporting the CAG subscription of the terminal equipment in the first communication system, then the release process is initiated, and the connection of the terminal equipment is released. Exemplarily, when the first communication system is 5GS and the second communication system is EPS, the first access network device and the second access network device are NG-RAN.

As shown in fig. 6, the first correlation procedure includes the following steps:

step S601, the first access network device sends a first message to the AMF, where the first message includes a registration request of the terminal device, the registration request is used to request to register to the first communication system, the registration request includes mobility information, and the mobility information indicates that the terminal device is from the second communication system.

Accordingly, the AMF receives a first message from the first access network device.

In this embodiment, before the first access network device sends the first message to the AMF, the first access network device may receive a registration request from the terminal device, and then encapsulate the registration request in the first message and send the first message to the AMF.

And the registration request comprises the mobility information of the terminal equipment, and the mobility information indicates that the terminal equipment comes from the second communication system. Thus, the AMF can know that the terminal device is handed over from the second communication system to the first communication system, that is, performs the cross-system handover, according to the mobility information. Exemplarily, the second communication system is an EPS, and the mobility information may indicate that the terminal device is from the EPS, such as "UE is moving from EPS". Optionally, the registration request may further include registration type information of the terminal device, where the registration type information is used to indicate that the registration type of the terminal device is mobility registration update (mobility registration update).

Optionally, the first access network device may send the cell CAG capability information to the AMF through the first message, where the first message includes the registration request of the terminal device and the cell CAG capability information of the first access network device, so that the AMF determines, after receiving the registration request of the terminal device, whether the first access network device supports CAG subscription of the terminal device according to the cell CAG capability information. It is to be understood that the first access network device may also send the cell CAG capability information to the AMF through other messages, which is not limited in this application.

In one possible design, the first message may be sent by the first access network device over an N2 interface with the AMF, belonging to the N2 message. The registration request may be sent by the terminal device over an air interface with the first access network device as a Non Access Stratum (NAS) message.

The first message and the registration request may be referred to as a registration request message or have other names, and the application is not limited thereto. Illustratively, the first message may be an Uplink NAS Transport message or an Initial UE message, and the Registration Request may be a Registration Request.

Step S602, the AMF obtains the CAG subscription of the terminal equipment.

In this embodiment of the present application, after receiving a registration request of a terminal device, the AMF may obtain, from the UDM, a CAG subscription of the terminal device, and optionally, the UDM is an HSS + UDM network element in which the UDM and the HSS are jointly arranged. The specific implementation of step S602 may refer to the above description related to step S401, and is not repeated herein.

Step S603, if the AMF determines that the first access network device does not support the CAG subscription of the terminal device, the AMF sends a second message or a third message to the first access network device according to the mobility information, where the second message or the third message includes the CAG subscription of the terminal device.

Accordingly, the first access network device receives the second message or the third message from the AMF.

That is, in the first related procedure, the AMF instructs the first access network device to initiate the intra-system handover or release procedure in a manner of sending the second message to the first access network device, and carrying the CAG subscription of the terminal device therein.

Optionally, if the AMF determines that the first access network device does not support the CAG subscription of the terminal device, and the terminal device has an ongoing session associated with the PNI-NPN information, the AMF sends the second message or the third message to the first access network device according to the mobility information. The AMF determines whether the first access network device supports the CAG subscription of the terminal device, and determines that the terminal device has a specific implementation manner of a session in progress, which is associated with the PNI-NPN information, which may be described in the foregoing step S402 and is not described again.

In one possible design, the second message and the third message may be sent by the AMF through an N2 interface with the first access network device, belonging to the N2 message.

It should be noted that, if the first message does not carry the cell CAG capability information of the first access network device, the AMF does not obtain the cell CAG capability information of the first access network device in other manners, in this case, the AMF may consider that the first access network device does not support the CAG subscription of the terminal device, and decide to send the second message or the third message to the first access network device based on the determination (optionally, according to whether the terminal device currently has a session associated with the PNI-NPN information) and the indication of the mobility information, although the determination may be inaccurate at this time. The situation can be understood that, when the AMF cannot determine whether the first access network device supports the CAG subscription of the terminal device or does not support the CAG subscription of the terminal device, the AMF selects to execute the same step or action when the first access network device does not support the CAG subscription of the terminal device, so as to avoid that the terminal device accesses the cell of the access network device which does not support the CAG subscription thereof, and the service cannot be performed.

Step S604, when the first access network device does not support the CAG subscription of the terminal device, initiating an intra-system handover or release procedure according to the CAG subscription of the terminal device.

In the embodiment of the application, after receiving the second message or the third message from the AMF, the first access network device may determine whether it supports the CAG subscription of the terminal device, and if not, initiate an intra-system handover procedure or a release procedure further according to the CAG subscription of the terminal device.

In a possible implementation manner (hereinafter referred to as implementation one), if the AMF determines that the first access network device does not support CAG subscription of the terminal device, the AMF sends a second message to the first access network device according to the mobility information, where the second message is used to indicate or request intra-system handover or release of the terminal device. The second message includes a CAG subscription of the terminal device and a cause value (cause code) indicating that the CAG subscription of the terminal device is not supported.

Thus, after receiving the second message from the AMF, the first access network device may determine that the CAG subscription of the terminal device is not supported according to the cause value therein, and then initiate an intra-system handover or release procedure according to the CAG subscription of the terminal device.

Further, the first access network device may further send a sixth message to the AMF, where the sixth message is used to notify the AMF to wait for the subsequent first access network device to initiate an intra-system handover procedure, or to notify the AMF to initiate a release procedure or wait for the first access network device to initiate a release procedure, in response to the second message.

In the first embodiment, the second message may be referred to as a handover request message or a release request message or by other names, and the sixth message may be referred to as a handover response message or a handover accept/reject message or a release response message or by other names, which are not limited in this application. For example, the second message may be a UE HO request message or a UE (context) release request/Command message, and the sixth message may be a UE HO response message or a UE (context) release response/Ack message.

In this embodiment, it may be understood that the AMF explicitly instructs (or requests) the first access network device to initiate an intra-system handover or release procedure by sending a handover request message or a release request message.

It should be noted that, in the first embodiment, in response to the registration request of the terminal device, the AMF may further send a registration acceptance or a registration rejection to the first access network device, and then send the registration acceptance or the registration rejection to the terminal device through the first access network device, so as to notify the terminal device whether the AMF accepts the registration request.

For example, in one possible design, the AMF may send an N2 message to the first access network device (i.e., send one message over the N2 interface with the first access network device) before sending the second message to the first access network device. The N2 message includes a registration accept of the terminal device, which indicates that the AMF accepts the registration request of the terminal device. The N2 message may be a downlink NAS Transport message or other messages, and the application is not limited thereto.

In another possible design, the AMF may decide whether to accept the registration request of the terminal device based on the content notified by the sixth message (i.e., according to whether the terminal device needs to perform an intra-system handover or a release) after receiving the sixth message from the first access network device, and further send a seventh message to the first access network device. If the terminal equipment needs to perform the intra-system handover, the AMF can accept the registration request of the terminal equipment and carry the registration acceptance of the terminal equipment in the seventh message. If the terminal device needs to be released, the AMF may reject the registration request of the terminal device and carry the registration rejection of the terminal device in the seventh message. In other words, if the sixth message is used to notify the AMF to wait for the subsequent first access network device to initiate the intra-system handover procedure, the seventh message may include a registration acceptance of the terminal device, where the registration acceptance is used to indicate the AMF to accept the registration request of the terminal device; if the sixth message is used to notify the AMF to initiate the release procedure or wait for the first access network device to initiate the release procedure, the seventh message may include a registration rejection of the terminal device, where the registration rejection is used to instruct the AMF to reject the registration request of the terminal device. Further, the first access network device may send the received registration acceptance or registration rejection to the terminal device.

It is to be understood that, in the above two possible designs of the first embodiment, the registration acceptance or the registration rejection may be sent by the first access network device over an air interface with the terminal device, belonging to the NAS message. And the sixth message may be sent by the first access network device over an N2 interface with the AMF as an N2 message, and the seventh message may be sent by the AMF over an N2 interface with the first access network device as an N2 message.

In another possible implementation (hereinafter referred to as implementation two), if the AMF determines that the first access network device does not support the CAG subscription of the terminal device, the AMF sends a third message to the first access network device according to the mobility information, where the third message includes the CAG subscription of the terminal device and a registration acceptance, and the registration acceptance is used to indicate the AMF to accept the registration request of the terminal device.

Thus, after the first access network device receives the third message from the AMF, on one hand, it may determine whether to support the CAG subscription of the terminal device according to the cell CAG capability information, and if not, initiate an intra-system handover or release procedure according to the CAG subscription of the terminal device. Correspondingly, the AMF may wait for the first access network device to initiate an intra-system handover procedure or a release procedure. In another aspect, the first access network device may also send the registration acceptance of the terminal device in the third message to the terminal device to notify the terminal device that it has successfully registered with the first communication system.

In the second embodiment, the third message may be a Downlink NAS Transport message or other messages, which is not limited in this application.

In one possible design, the registration acceptance may be sent by the first access network device over an air interface with the terminal device as a NAS message. For example, the Registration Accept may be a Registration Accept message.

In the second embodiment, it may be understood that, by sending the third message, the AMF implicitly indicates to the first access network device to perform the determination according to the CAG subscription of the terminal device, so as to initiate an intra-system handover or release procedure.

In the second embodiment, the AMF may not determine whether the first access network device supports CAG subscription of the terminal device. That is, the AMF may not determine whether the first access network device supports the CAG subscription of the terminal device, that is, send the third message to the first access network device.

Therefore, in the registration process of the terminal device, the AMF can know that the terminal device is switched from the second communication system to the first communication system according to the mobility information in the registration request of the terminal device. And then, according to the CAG subscription of the terminal equipment and in consideration of the mobility information, performing access control on the terminal equipment. If the first access network device does not support the CAG subscription of the terminal device (or further determines that the terminal device has an ongoing session associated with the PNI-NPN information), considering that the mobility information indicates that the terminal device is from the second communication system, the AMF may not reject the registration request of the terminal device and may not directly release the connection of the terminal device, but instruct the first access network device to initiate an intra-system handover procedure or a release procedure by sending a second message or a third message to the first access network device and carrying the CAG subscription of the terminal device, so as to handover the terminal device to the second access network device supporting the CAG subscription in the first communication system.

Fig. 7 to 9 are some specific examples of the related flow one. For convenience of understanding, in these specific examples, the first communication system is a 5G communication system (i.e., 5GS), the second communication system is a 4G communication system (i.e., EPS), the terminal device is a UE, the first access network device is NG-RAN1, and the second access network device is NG-RAN 2.

Example 1

As shown in fig. 7, example 1 includes the steps of: step S701, the UE sends a registration request to the first access network device, where the registration request is used to request to register the UE to the 5GS, and the registration request includes mobility information, where the mobility information is "UE is moving from EPS" and is used to indicate that the UE is from EPS. Optionally, the registration request further includes registration type information, where the registration type information is used to indicate that the registration type of the UE is mobility registration update. Illustratively, the registration request is a NAS message, such as a registration request.

In step S702, the NG-RAN1 transmits an N2 message to the AMF, the N2 message including a registration request of the UE and cell CAG capability information of the NG-RAN 1. Wherein the cell CAG capability information of the NG-RAN1 is used to indicate whether the cell of the NG-RAN1 supports CAG functionality and, if so, the identity of one or more CAGs supported by the cell (i.e. a supported CAG list of cells). Illustratively, the N2 message is an Uplink NAS Transport message or an Initial UE message.

Step S703, the AMF acquires the CAG subscription of the UE from the UDM. Wherein the CAG subscription of the UE is used to indicate the identity of one or more CAGs allowed by the UE and/or whether the UE is allowed to access the 5GS only through the CAG cell. Illustratively, the AMF may send a numm _ SDM _ Get Request message to the UDM and receive a numm _ SDM _ Get Response message from the UDM, resulting in a CAG subscription for the UE.

In step S704, the AMF determines whether the NG-RAN1 supports CAG subscription of the UE according to the cell CAG capability information of the NG-RAN 1. Optionally, the AMF further determines whether the UE has an ongoing session associated with the PNI-NPN information according to the context of the UE. The step S704 is optional.

In step S705, the AMF sends an N2 message to the NG-RAN1, where the N2 message includes CAG subscription and registration acceptance of the UE. The CAG subscription of the UE is used for the NG-RAN1 to determine whether the NG-RAN1 supports the CAG subscription of the UE, and to decide whether to initiate an intra-system handover procedure or a release procedure, and the registration acceptance is used to indicate the AMF to accept the registration request of the UE. Illustratively, the N2 message is a Downlink NAS Transport, and the registration accept is a NAS message, such as registration accept.

Alternatively, if the AMF determines that the NG-RAN1 does not support CAG subscription for the UE (or further alternatively, that the UE has an ongoing session associated with PNI-NPN information), the AMF sends an N2 message to the NG-RAN 1.

Optionally, the AMF sends an N2 message to the NG-RAN1 based on the mobility information. The AMF sending the N2 message to the NG-RAN1 according to the mobility information may be that the AMF determines that the registration request of the UE includes the mobility information indicating that the UE is from the EPS and sends the N2 message to the NG-RAN1, or that the AMF determines that the UE performs cross-system handover and sends the N2 message to the NG-RAN 1.

In step S706, the NG-RAN1 determines whether or not to support CAG subscription of the UE according to the cell CAG capability information.

Step S707, if the CAG subscription of the UE is not supported, the NG-RAN1 initiates an intra-system handover or release procedure according to the CAG subscription of the UE. For example, the NG-RAN1 initiates a release procedure to release the air interface connection with the UE. Alternatively, NG-RAN1 attempts to discover other NG-RANs in the 5GS that support the CAG subscription for the UE. If the NG-RAN2 is found to be able to support CAG subscription for the UE, then the NG-RAN1 initiates an intra-system handover procedure to handover the UE to the NG-RAN 2. Alternatively, if no NG-RAN2 is found that can support the CAG subscription of the UE, the release procedure is initiated.

Optionally, example 1 further comprises the NG-RAN1 sending a registration acceptance to the UE, step S708. It should be noted that step S708 is executed after step S705, but the order of step S708, step S706 and step S707 is not specifically limited in this application.

As can be seen from the above, in this example 1, when the UE is handed over from the EPS to the NG-RAN1 in the 5GS and the NG-RAN1 does not support the CAG subscription of the UE, the AMF may, after receiving the registration request of the UE, instruct the NG-RAN1 to initiate a handover procedure or a release procedure within the 5GS according to the CAG subscription of the terminal device by sending an N2 message to the NG-RAN1 and carrying the CAG subscription of the terminal device, thereby facilitating handover of the terminal device to another NG-RAN in the 5GS that supports its CAG subscription.

Example 2

As shown in fig. 8, example 2 includes the steps of: in step S801, the UE sends a registration request to the NG-RAN1, where the registration request is used to request that the UE be registered with the 5GS, and the registration request includes mobility information, where the mobility information is "UE is moving from EPS" and is used to indicate that the UE is from EPS. Optionally, the registration request further includes registration type information, where the registration type information is used to indicate that the registration type of the UE is mobility registration update. Illustratively, the registration request is a NAS message, such as a registration request.

At step S802, the NG-RAN1 transmits an N2 message to the AMF, the N2 message including a registration request of the UE and cell CAG capability information of the NG-RAN 1. Wherein the cell CAG capability information of the NG-RAN1 is used to indicate whether the cell of the NG-RAN1 supports CAG functionality and, if so, the identity of one or more CAGs supported by the cell (i.e. a supported CAG list of cells). Illustratively, the N2 message is an Uplink NAS Transport message or an Initial UE message.

Step S803, the AMF acquires CAG subscription of the UE from the UDM. Wherein, the CAG subscription of the UE is used for indicating the identity of one or more CAGs allowed by the UE and/or whether the UE allows only 5GS to be accessed through a CAG cell. Illustratively, the AMF may send a numdm _ SDM _ Get Request message to the UDM and receive a numdm _ SDM _ Get Response message from the UDM, resulting in CAG subscription for the UE.

Step S804, the AMF judges whether the NG-RAN1 supports CAG subscription of the UE according to the cell CAG capability information of the NG-RAN 1. The AMF can further judge whether the UE has an ongoing session associated with the PNI-NPN information according to the context of the UE. The step S804 is optional.

At step S805, the AMF transmits a handover request message including a CAG subscription and a cause value (cause code) of the UE to the NG-RAN 1. Where the CAG subscription of the UE is used for the NG-RAN1 to decide whether to initiate an intra-system handover procedure or a release procedure. The cause value is used to indicate that the CAG subscription of the UE is not supported, or not satisfied. Illustratively, the handover request message is an N2 message, such as a UE HO request message.

Alternatively, if the AMF determines that the NG-RAN1 does not support CAG subscription for the UE (or further that the UE has an ongoing session associated with PNI-NPN information), the AMF sends a handover request message to the NG-RAN 1.

Optionally, the AMF sends a handover request message to the NG-RAN1 based on the mobility information. The AMF sending the handover request message to the NG-RAN1 according to the mobility information may be that the AMF determines that the registration request of the UE includes the mobility information indicating that the UE is from the EPS and sends the handover request message to the NG-RAN1, or that the AMF determines that the UE performs cross-system handover and sends the handover request message to the NG-RAN 1.

In step S806, the NG-RAN1 determines that the CAG subscription of the UE is not supported according to the cause value in the handover request message.

In step S807, NG-RAN1 initiates an intra-system handover or release procedure according to the CAG subscription of the UE. For example, the NG-RAN1 initiates a release procedure to release the air interface connection with the UE. Alternatively, NG-RAN1 attempts to discover other NG-RANs in the 5GS that support the CAG subscription for the UE, and if NG-RAN2 is found to be able to support the CAG subscription for the UE, an intra-system handover procedure is initiated to handover the UE to the NG-RAN 2. Alternatively, if no NG-RAN2 is found that can support the CAG subscription of the UE, the release procedure is initiated.

The NG-RAN1 sends a handover response message to the AMF at step S808. If the NG-RAN1 decides to initiate the intra-system handover procedure, the handover response message includes an acceptance indication message, where the acceptance indication message is used to notify the AMF to wait for the subsequent NG-RAN1 to initiate the intra-system handover procedure, and the handover response message may also be referred to as a handover acceptance message. If the NG-RAN1 decides to initiate the release procedure, the handover response message includes rejection indication information for informing the AMF to initiate the release procedure or waiting for the subsequent NG-RAN1 to initiate the release procedure, and the handover response message may also be referred to as a handover rejection message. Illustratively, the handover response message is an N2 message, such as a UE HO response message, or a UE HO accept message, or a UE HO reject message.

The AMF sends a registration acceptance or a registration rejection to the UE by sending an N2 message to the NG-RAN1 at step S809. Wherein the registration accept indicates that the AMF accepts the registration request of the UE, and the registration reject indicates that the AMF rejects the registration request of the UE. Illustratively, the N2 message is Downlink NAS Transport, and the registration accept and registration reject are NAS messages, for example, registration accept is registration accept and registration reject is registration reject.

Optionally, the AMF sends a registration acceptance or a registration rejection to the UE by sending an N2 message to the NG-RAN1, depending on whether an intra-system handover or release is required for the UE. Illustratively, when the AMF includes the acceptance indication information in the handover response message received at step S808, the AMF transmits a registration acceptance message to the UE by transmitting an N2 message to the NG-RAN 1. When the AMF receives the handover response message including the rejection indication information at S808 or receives the handover reject message, the AMF transmits a registration reject message to the UE by transmitting an N2 message to the NG-RAN 1.

Optionally, step S810 is further included, where the NG-RAN1 sends the registration acceptance or the registration rejection of the UE received from the AMF to the UE.

As can be seen from the above, in this example 2, when the UE is handed over from the EPS to the NG-RAN1 in the 5GS and the NG-RAN1 does not support the CAG subscription of the UE, the AMF may decide, by the NG-RAN1, whether to initiate the handover procedure within the 5GS or the release procedure according to the CAG subscription of the terminal device by sending a handover request message to the NG-RAN1 and carrying the CAG subscription of the terminal device after receiving the registration request of the UE, thereby facilitating the handover of the terminal device to the other NG-RAN supporting its CAG subscription in the 5 GS.

Example 3

As shown in fig. 9, example 3 includes the steps of: in step S901, the UE sends a registration request to the NG-RAN1, where the registration request is used to request that the UE be registered in the 5GS, and the registration request includes mobility information, where the mobility information is "UE is moving from EPS" and is used to indicate that the UE is from the EPS. Optionally, the registration request further includes registration type information, where the registration type information is used to indicate that the registration type of the UE is mobility registration update. Illustratively, the registration request is a NAS message, such as a registration request.

At step S902, the NG-RAN1 transmits an N2 message to the AMF, the N2 message including a registration request of the UE and cell CAG capability information of the NG-RAN 1. Wherein the cell CAG capability information of the NG-RAN1 is used to indicate whether the cell of the NG-RAN1 supports CAG functionality and, if so, the identity of one or more CAGs supported by the cell (i.e. a supported CAG list of cells). Illustratively, the N2 message is an Uplink NAS Transport message or an Initial UE message.

Step S903, the AMF acquires CAG subscription of the UE from the UDM. Wherein, the CAG subscription of the UE is used for indicating the identity of one or more CAGs allowed by the UE and/or whether the UE allows only 5GS to be accessed through a CAG cell. Illustratively, the AMF may send a numm _ SDM _ Get Request message to the UDM and receive a numm _ SDM _ Get Response message from the UDM, resulting in a CAG subscription for the UE.

In step S904, the AMF determines whether the NG-RAN1 supports CAG subscription of the UE according to the cell CAG capability information of the NG-RAN 1. The AMF can further judge whether the UE has an ongoing session associated with the PNI-NPN information according to the context of the UE. The step S904 is optional.

Step S905, the AMF sends a release request message to the NG-RAN1, where the release request message includes the CAG subscription and the cause value of the UE, and the CAG subscription of the UE is used by the NG-RAN1 to decide whether to initiate an intra-system handover procedure or a release procedure. The cause value is used to indicate that the CAG subscription of the UE is not supported, or not satisfied. Illustratively, the release request message is an N2 message, such as a UE context release request message. Optionally, the AMF sends a release request message to the NG-RAN1 based on the mobility information.

Alternatively, if the AMF determines that the NG-RAN1 does not support CAG subscription for the UE (or further that the UE has an ongoing session associated with PNI-NPN information), the AMF sends a release request message to the NG-RAN 1.

Alternatively, the AMF sends a release request message to the NG-RAN1 according to the mobility information. The sending, by the AMF, the release request message to the NG-RAN1 according to the mobility information may be that the AMF determines that the registration request of the UE includes the mobility information indicating that the UE is from the EPS and sends the release request message to the NG-RAN1, or that the AMF determines that the UE performs cross-system handover and sends the release request message to the NG-RAN 1.

In step S906, the NG-RAN1 determines that the CAG subscription of the UE is not supported according to the cause value in the release request message.

In step S907, the NG-RAN1 initiates an intra-system handover or release procedure according to the CAG subscription of the UE. For example, the NG-RAN1 initiates a release procedure to release the air interface connection with the UE. Alternatively, NG-RAN1 attempts to discover other NG-RANs in the 5GS that support the CAG subscription for the UE, and if NG-RAN2 is found to be able to support the CAG subscription for the UE, an intra-system handover procedure is initiated to handover the UE to the NG-RAN 2. Alternatively, if no NG-RAN2 is found that can support the CAG subscription of the UE, the release procedure is initiated.

The NG-RAN1 sends a release response message to the AMF at step S908. Wherein, if the NG-RAN1 decides to initiate the intra-system handover procedure, the release response message includes handover indication information, which is used to inform the AMF to wait for the subsequent NG-RAN1 to initiate the intra-system handover procedure. If the NG-RAN1 decides to initiate the release procedure, the release response message includes release indication information, which is used to inform the AMF to initiate the release procedure or wait for the subsequent NG-RAN1 to initiate the release procedure. Illustratively, the release response message is an N2 message, such as a UE context release response message.

The AMF sends a registration acceptance or a registration rejection to the UE by sending an N2 message to the NG-RAN1 at step S909. Wherein the registration accept indicates that the AMF accepts the registration request of the UE, and the registration reject indicates that the AMF rejects the registration request of the UE. Illustratively, the N2 message is Downlink NAS Transport, and the registration accept and registration reject are NAS messages, for example, registration accept is registration accept and registration reject is registration reject.

Optionally, the AMF sends a registration acceptance or a registration rejection to the UE by sending an N2 message to the NG-RAN1, depending on whether an intra-system handover or release is required for the UE. Illustratively, when the AMF includes handover indication information in the release response message received at step S908, the AMF transmits a registration accept message to the UE by transmitting an N2 message to the NG-RAN 1. When the AMF includes the release indication information in the release response message received at S908, the AMF transmits a registration reject message to the UE by transmitting an N2 message to the NG-RAN 1.

Optionally, step S910 is further included, where the NG-RAN1 sends the registration acceptance or the registration rejection of the UE received from the AMF to the UE.

As can be seen from the above, in this example 3, when the UE is handed over from the EPS to the NG-RAN1 in the 5GS and the NG-RAN1 does not support the CAG subscription of the UE, the AMF may decide, by the NG-RAN1, whether to initiate the handover procedure within the 5GS or the release procedure according to the CAG subscription of the terminal device by sending a release request message to the NG-RAN1 and carrying the CAG subscription of the terminal device after receiving the registration request of the UE, thereby facilitating the handover of the terminal device to the other NG-RAN supporting its CAG subscription in the 5 GS.

Correlation procedure two

The second related flow specifically relates to a cross-system handover process of the terminal device from the second communication system to the first communication system and a registration process after handover is completed.

In the cross-system switching process from the second communication system to the first communication system, the AMF in the first communication system may obtain the CAG subscription of the terminal device, and send the CAG subscription of the terminal device and the switching request together to the first access network device in the first communication system. After receiving the CAG subscription and the switching request of the terminal device, the first access network device can judge whether the first access network device supports the CAG subscription of the terminal device. If the CAG subscription of the terminal device is not supported, the first access network device may still accept the handover request, but locally record that intra-system handover or release is subsequently required and notify the AMF. In this way, in the subsequent registration process of the terminal device, when the AMF determines that the first access network device does not support the CAG subscription of the terminal device, the AMF may not directly release the connection of the terminal device, but wait for or request the first access network device to initiate an intra-system handover procedure, so that the terminal device can be handed over to a second access network device supporting the CAG subscription in the first communication system. And if the first access network equipment can not find the second access network equipment supporting the CAG subscription of the terminal equipment in the first communication system, releasing the connection of the terminal equipment.

It will be appreciated that the above-described cross-system handover procedure also involves a third access network device in the second communication system. In the cross-system switching process, the third access network device is a source access network device, and the first access network device is a target access network device. If there is handover in the first communication system after the cross-system handover, the first access network device is a source access network device and the second access network device is a target access network device in the intra-system handover process. Illustratively, when the first communication system is 5GS and the second communication system is EPS, the first access network device and the second access network device are NG-RAN and the third access network device is E-UTRAN.

As shown in fig. 10, the second correlation process includes the following steps:

step S1001, the MME sends a forwarding redirection request to the AMF, where the forwarding redirection request is used to request to redirect the terminal device to the AMF.

Accordingly, the AMF receives a forward redirection request from the MME.

In this embodiment of the present application, before the MME sends the forwarding redirection request to the AMF, the third access network device in the second communication system may execute a handover initialization (handover initialization) process to trigger the terminal device to switch from the second communication system to the first communication system. The third access network device may send a handover required message to the MME, and the MME sends a forward redirection request to the AMF according to the received handover request message.

In one possible design, the forward redirect request may be sent by the MME over an N26 interface with the AMF. The forward redirection request may be referred to as a forward redirection request message or by another name, which is not limited in this application.

Optionally, after receiving the forwarding redirection request from the MME, the AMF may obtain the context of the terminal device. Illustratively, the process may include: the AMF sends an Nsmf _ PDUSESSion _ CreatesMContext Request message to the PGW-C + SMF, and if the terminal equipment is attached to a roaming network, the AMF can forward the message to the PGW-C + SMF through the Default V-SMF. Then, PGW-C + SMF may trigger the SMF Initiated SM Policy Association Modification procedure and the N4Session Modification procedure in sequence. Furthermore, the PGW-C + SMF may send an Nsmf _ pdusesion _ CreateSMContext Response message to the AMF, if the terminal device is attached to the roaming network, the PGW-C + SMF may forward the message to the AMF through the Default V-SMF, and the Default V-SMF may trigger the N4Session Establishment procedure.

Alternatively, assuming that the current AMF is denoted as an initial (initial) AMF, if the initial AMF is suitable for providing service to the terminal device, the AMF may continue to perform subsequent steps, and the AMF described in the following of the present application is the initial AMF. If the initial AMF is not suitable for serving the terminal device, the initial AMF may select a target (target) AMF and send a Namf _ Communication _ CreateUEContext Request message including a context of the terminal device to the target AMF, so as to give a processing right of access control to the target AMF. In this case, the AMF described hereinafter in this application refers to the target AMF, not the initial AMF.

Step S1002, the AMF acquires the CAG subscription of the terminal equipment.

In this embodiment of the present application, the AMF may obtain, from the UDM, a CAG subscription of the terminal device after receiving the forwarding redirection request from the MME, and optionally, the UDM is an HSS + UDM network element where the UDM and the HSS are jointly configured. The specific implementation of step S1002 can refer to the related description of step S401, and repeated descriptions are omitted here.

In one possible design, the AMF may obtain a CAG subscription for the terminal device from the UDM when the terminal device switches from the second communication system to the first communication system. In another possible design, the AMF may determine whether to acquire a CAG subscription of the terminal device according to a context of the terminal device. If the terminal device has an ongoing session associated with the PNI-NPN information or the usage type (usage type) of the terminal device is a specific usage type, the AMF may obtain a CAG subscription of the terminal device from the UDM. The specific process of the AMF obtaining the CAG subscription of the terminal device from the UDM may refer to the related description above, and is not described herein again. It can be understood that, before obtaining the CAG subscription of the terminal device, what kind of determination needs to be performed by the AMF may be configured by the AMF, and the present application is not limited specifically.

Step S1003, the AMF sends a handover request to the first access network device, where the handover request is used to request to handover the terminal device to the first access network device, and the handover request includes a CAG subscription of the terminal device.

Accordingly, the first access network device receives a handover request from the AMF.

In this embodiment of the present application, after receiving a forwarding redirection request from an MME, an AMF may decide to switch a terminal device to a first access network device, and send a switch request to the first access network device.

Optionally, the handover request further includes handover type information, where the handover type information is used to indicate handover from the second communication system to the first communication system. By carrying the switching type information in the switching request, the first access network device can conveniently judge whether to accept the switching request of the terminal device.

In one possible design, the handover request may be sent by the AMF over an N2 interface with the first access network device, belonging to an N2 message. The handover request may be referred to as a handover request (handover request) message or by other names, and the application is not limited thereto.

Step S1004, if the first access network device does not support CAG subscription of the terminal device, the first access network device sends a handover request response to the AMF, where the handover request response is used to indicate that the handover request is accepted, and the handover request response includes first indication information, where the first indication information is used to indicate that the terminal device needs to perform intra-system handover or release subsequently.

Accordingly, the AMF receives a handover request response from the first access network device.

In this embodiment of the present application, after receiving a handover request from the AMF, the first access network device may determine whether or not it supports CAG subscription of the terminal device according to the cell CAG capability information. If the first access network device does not support the CAG subscription of the terminal device, the first access network device may still accept the handover request, and send a handover request response to the AMF, indicating that the handover request is accepted, but carrying the first indication information in the handover request response, so as to notify the AMF that the terminal device needs to perform intra-system handover or release subsequently.

The first indication information may also be understood as being used to notify the AMF to not reject registration of the terminal device because the CAG subscription is not satisfied in the registration process of the subsequent terminal device, or directly release the connection of the terminal device, but to instruct (or request) the AMF to initiate an intra-system handover or release procedure. The first indication information may also be referred to as a subsequent handover indication or have other names, and the application is not limited thereto.

Optionally, the first access network device may further consider handover type information in the handover request when deciding whether to accept the handover request. That is, when the first access network device does not support the CAG subscription of the terminal device and the handover type information indicates that the handover is a cross-system handover from the second communication system to the first communication system, the first access network device may still accept the handover request and send a handover request response to the AMF, but the first indication information is carried in the handover request response.

In one possible design, the handover request response may be sent by the first access network device over an N2 interface with the AMF, belonging to the N2 message. The handover request response may be referred to as a handover request acknowledgement message or by other names, and the application is not limited thereto.

Step S1005, the first access network device sends a fourth message to the AMF, where the fourth message is used to notify the AMF that the terminal device is switched, or the fourth message includes a registration request of the terminal device, and the registration request is used to request to register to the first communication system.

In this embodiment of the application, if the fourth message is used to notify the AMF terminal device that the handover is completed, the fourth message may be a handover notification (handover notify) message. The fourth message may be a registration request message if the registration request of the terminal device is included in the fourth message. Illustratively, the fourth message may be an Uplink NAS Transport message or an Initial UE message, and the Registration Request may be a Registration Request.

Optionally, the fourth message includes cell CAG capability information of the first access network device, so that the AMF may subsequently determine whether the first access network device supports CAG subscription of the terminal device according to the cell CAG capability information.

In one possible design, the fourth message may be sent by the first access network device over an N2 interface with the AMF, belonging to the N2 message.

It should be noted that, after the first access network device sends the handover request response to the AMF to indicate that the handover request is accepted, the terminal device may complete the handover procedure from the third access network device of the second communication system to the first access network device of the first communication system. The Handover procedure may include all or part of the following operations or steps, for example, the AMF sends a redirection response message to the MME, the MME sends a Handover command message to the third access network device, the third access network device sends a Handover command message to the terminal, the terminal device receives a Handover command from the third access network device, performs random access to the first access network device according to the Handover command, sends a Handover completion to the first access network device, and the first access network device sends a Handover notification (Handover notification) to the AMF. Subsequent operations or steps belong to the registration procedure of the terminal device after the first access network device sends the fourth message to the AMF. Wherein the handover notification message indicates completion of the handover procedure and the registration request message indicates start of the registration procedure.

Optionally, after the inter-system handover of the terminal device is completed, the intra-system handover or release may be subsequently performed, so that after receiving a handover request response from the first access network device, the AMF may set a flag information (flag) in the memory according to the first indication information, so as to remind that the CAG subscription of the terminal device is not satisfied, and further determination may be performed in the registration process, so as to perform the intra-system handover or release. The flag information may be cleared when the terminal device completes an intra-system handover or release.

Step S1006, the AMF sends a fifth message to the first access network device according to the first indication information, where the fifth message is used to indicate or request to perform intra-system handover or release on the terminal device, and the fifth message includes a cause value, where the cause value is used to indicate that the CAG subscription of the terminal device is not supported.

Accordingly, the first access network device receives the fifth message from the AMF.

That is, in the second related procedure, the AMF instructs the first access network device to initiate the intra-system handover or release procedure in a manner of sending the fifth message to the first access network device, where the fifth message carries the cause value.

In a possible implementation, after receiving the fourth message from the first access network device, the AMF may send a fifth message to the first access network device according to the previously received first indication information (i.e. considering that the terminal device needs to perform an intra-system handover or release) to instruct the first access network device to initiate an intra-system handover or release procedure.

In another possible implementation, the AMF may determine, after receiving the fourth message from the first access network device, whether the first access network device supports CAG subscription of the terminal device, or further determine whether the terminal device has an ongoing session associated with PNI-NPN information. If the AMF determines that the first access network device does not support CAG subscription of the terminal device and the terminal device has an ongoing session associated with the PNI-NPN information, the AMF may send a fifth message to the first access network device according to the first indication information (that is, considering that the terminal device needs to perform intra-system handover or release) to indicate the first access network device to initiate an intra-system handover or release procedure.

In one possible design, the fifth message may be sent by the AMF over an N2 interface with the first access network device, belonging to the N2 message.

Step S1007, when the first access network device does not support the CAG subscription of the terminal device, initiating an intra-system switching or releasing process according to the CAG subscription of the terminal device.

In the embodiment of the application, after receiving the fifth message from the AMF, the first access network device may determine that the CAG subscription of the terminal device is not supported according to the cause value therein, and then initiate an intra-system handover procedure or a release procedure according to the CAG subscription of the terminal device.

Further, after deciding to initiate the intra-system handover or release procedure, the first access network device may further send a sixth message to the AMF, where the sixth message is used to notify the AMF to wait for the subsequent first access network device to initiate the intra-system handover procedure, or to notify the AMF to initiate the release procedure or wait for the first access network device to initiate the release procedure, in response to the fifth message.

In the related flow two, the fifth message may be referred to as a handover request message or a release request message or have other names, and the sixth message may be referred to as a handover response message or a handover accept/reject message or a release response message or have other names, which are not limited in this application. For example, the fifth message may be a UE HO request message or a UE (context) release request/Command message, and the sixth message may be a UE HO response message or a UE (context) release response/Ack message.

It should be noted that, in response to the registration request of the terminal device, the AMF may further send a registration acceptance or a registration rejection to the first access network device, and then send the registration acceptance or the registration rejection to the terminal device through the first access network device, so that the terminal device knows whether the AMF accepts its registration request.

For example, in one possible design, the AMF may send an N2 message to the first access network device before sending the fifth message to the first access network device, the N2 message including a registration accept for the terminal device, the registration accept indicating that the AMF accepts the registration request for the terminal device. After receiving the N2 message, the first access network device may further send a registration acceptance thereof to the terminal device.

In another possible design, the AMF may decide whether to accept the registration request of the terminal device based on the content notified by the sixth message (i.e., according to whether the terminal device needs to perform an intra-system handover or a release) after receiving the sixth message from the first access network device, and then send the seventh message to the first access network device. If the terminal equipment needs to perform the intra-system handover, the AMF can accept the registration request of the terminal equipment and carry the registration acceptance of the terminal equipment in the seventh message. If the terminal device needs to be released, the AMF may reject the registration request of the terminal device and carry the registration rejection of the terminal device in the seventh message. In other words, if the sixth message is used to notify the AMF to wait for the subsequent first access network device to trigger the intra-system handover procedure, the seventh message includes the registration acceptance of the terminal device, where the registration acceptance is used to indicate that the AMF accepts the registration request of the terminal device. If the sixth message is used to notify the AMF to trigger the release procedure or wait for the first access network device to trigger the release procedure, the seventh message includes a registration rejection of the terminal device, where the registration rejection is used to instruct the AMF to reject the registration request of the terminal device.

In one possible design, the seventh message may be sent by the AMF over an N2 interface with the first access network device, belonging to the N2 message. The registration accept may be sent by the first access network device over an air interface with the terminal device, belonging to a NAS message.

Therefore, in the cross-system switching process of the terminal device, the first access network device may determine according to the CAG subscription of the terminal device in the switching request, and when the CAG subscription of the terminal device is not supported and the terminal device is switched from the second communication system to the first communication system, the first access network device still receives the switching request, but carries the first indication information in the switching request response to indicate that the AMF subsequently needs to perform intra-system switching or release on the terminal device. Furthermore, in the registration process of the terminal device, after receiving the fifth message from the first access network device, the AMF may perform access control on the terminal device according to the first indication information. If the first access network device does not support the CAG subscription of the terminal device (or further the terminal device has an ongoing session associated with the PNI-NPN information), considering that the first indication information indicates that the terminal device needs to perform intra-system handover or release, the AMF may not reject the registration request of the terminal device, and may not directly release the connection of the terminal device, but send a sixth message to the first access network device and carry a cause value to indicate that the first access network device initiates an intra-system handover procedure or a release procedure because the CAG subscription of the terminal device is not satisfied, so as to switch the terminal device to a second access network device supporting its CAG subscription in the first communication system.

Fig. 11 is a specific example of the related flow two. For convenience of understanding, in this specific example, the first communication system is a 5G communication system (i.e., 5GS), the second communication system is a 4G communication system (i.e., EPS), the terminal device is a UE, the first access network device is NG-RAN1, the second access network device is NG-RAN2, and the third access network device is E-UTRAN.

Example 4

As shown in fig. 11, example 4 includes the steps of: step S1101, the UE establishes a Packet Data Network (PDN) session in the EPS.

Step S1102, the E-UTRAN executes a handover initialization (handover initialization) process to trigger the UE to switch from the EPS to the 5 GS.

Step S1103, the E-UTRAN sends a handover request to the MME, and the handover request is used for requesting to handover the terminal equipment to the 5 GS. Illustratively, the handover request is a handover required message.

Step S1104, the MME sends a forwarding redirection request to the AMF, where the forwarding redirection request is used to request to redirect the UE to the AMF, and the forwarding redirection request includes a context of the UE. Illustratively, the forward redirection request is a forward redirection request message.

In step S1105, the AMF acquires and updates the context of the UE. Exemplarily, the AMF sends an Nsmf _ PDUSESS _ CreatesMContext Request message to the PGW-C + SMF; if the UE is attached to the roaming network, the AMF may forward the message to the PGW-C + SMF through the Default V-SMF. Then, PGW-C + SMF may trigger the SMF Initiated SM Policy Association Modification procedure and the N4Session Modification procedure in sequence. Furthermore, the PGW-C + SMF may send an Nsmf _ pdusesion _ CreateSMContext Response message to the AMF, where the message includes a PDU Session ID, an S-NSSAI, and an SMF ID of a PDU Session of the UE, and if the UE is attached to the roaming network, the PGW-C + SMF may forward the message to the AMF through the Default V-SMF, and the Default V-SMF may trigger the N4Session Establishment procedure. And the AMF updates the context of the UE according to the Nsmf _ PDUSESS _ CreateSSContextResponse message, namely, the received association of the PDU Session ID, DNN, S-NSSAI and SMF ID of the PDU Session of the UE is stored in the context of the UE.

In other words, through step S1105, the AMF verifies the UE context acquired through step S1104, and updates information therein such as DNN, S-NSSAI, and SMF ID.

In step S1106, the AMF obtains the CAG subscription of the UE from the UDM.

Optionally, the AMF determines according to the context of the UE, and if the UE has an ongoing session associated with the PNI-NPN information, or a usage type (usage type) of the UE is a specific usage type, the AMF obtains a CAG subscription of the UE from the UDM. Wherein, the CAG subscription of the UE is used for indicating the identification of one or more CAGs to which the UE belongs and/or whether the UE only allows the 5GS access through the CAG cell. Illustratively, the AMF may send a numm _ SDM _ Get Request message to the UDM and receive a numm _ SDM _ Get Response message from the UDM, resulting in a CAG subscription for the UE.

In step S1107, the AMF sends a handover request to the NG-RAN1, the handover request requesting that the UE be handed over to the NG-RAN1, the handover request including the CAG subscription of the UE and handover type information indicating handover from EPS to 5 GS. Illustratively, the handover request is a handover request message.

In step S1108, the NG-RAN1 determines whether the CAG subscription of the UE is supported, and if the CAG subscription of the UE is not supported, the handover request is still received according to the handover type information, and a handover request response is sent to the AMF. The switching request response comprises first indication information, and the first indication information is used for indicating that the terminal equipment needs to perform intra-system switching or releasing subsequently. Illustratively, the handover request response is a handover request response message or a handover request ACK message.

Step S1109, the subsequent handover process is not described again.

At step S1110-a, the NG-RAN1 transmits to the AMF a handover notification message for notifying the AMF of the completion of handover of the UE, the handover notification message including cell CAG capability information of the NG-RAN 1. Illustratively, the handover notification message is an N2 message, such as a handover notify message.

In step S1110-b, the NG-RAN1 transmits an N2 message to the AMF, the N2 message including cell CAG capability information of the NG-RAN1 and a registration request of the UE. Illustratively, the N2 message is an Uplink NAS Transport message or an Initial UE message.

And step S1111, the AMF performs access control on the UE according to the cell CAG capability information of the NG-RAN1 and the CAG subscription of the UE. If the NG-RAN1 does not support CAG subscription of the UE (or further the UE has an ongoing session associated with PNI-NPN information), the AMF sends a handover request message or a release request message to the NG-RAN1 according to the first indication information. The handover request message or the release request message includes a cause value, where the cause value is used to indicate that the CAG subscription of the UE is not supported, or that the CAG subscription of the UE is not satisfied. Illustratively, the handover request message and the release request message are N2 messages, for example, the handover request message is a UE HO request message, and the release request message is a UE context release request message.

In step S1112, the NG-RAN1 initiates an intra-system handover or release procedure according to the CAG subscription of the UE. For example, the NG-RAN1 initiates a release procedure to release the air interface connection with the UE. Alternatively, NG-RAN1 attempts to discover other NG-RANs in the 5GS that support the CAG subscription for the UE, and if NG-RAN2 is found to be able to support the CAG subscription for the UE, an intra-system handover procedure is initiated to handover the UE to the NG-RAN 2. Alternatively, if no NG-RAN2 is found that can support the CAG subscription of the UE, the release procedure is initiated.

The NG-RAN1 transmits a handover response message or a release response message to the AMF at step S1113. For the handover response message, if the NG-RAN1 decides to initiate the intra-system handover procedure, the handover response message includes acceptance indication information, which is used to inform the AMF to wait for the subsequent NG-RAN1 to initiate the intra-system handover procedure, and at this time, the handover response message may also be referred to as a handover accept message. If the NG-RAN1 decides to initiate the release procedure, the handover response message includes rejection indication information for informing the AMF to initiate the release procedure or waiting for the subsequent NG-RAN1 to initiate the release procedure, and the handover response message may also be referred to as a handover rejection message. Illustratively, the handover response message is an N2 message, such as a UE HO response message, or a UE HO accept message, or a UE HO reject message.

For the release response message, if NG-RAN1 decides to initiate an intra-system handover procedure, the release response message includes handover indication information that informs the AMF to wait for the subsequent NG-RAN1 to initiate an intra-system handover procedure. If the NG-RAN1 decides to initiate the release procedure, release indication information is included in the release response message, which is used to inform the AMF to initiate the release procedure or to wait for the subsequent NG-RAN1 to initiate the release procedure. Illustratively, the release response message is an N2 message, such as a UE context release response message.

The AMF sends a registration acceptance or a registration rejection to the UE by sending an N2 message to the NG-RAN1 at step S1114. Wherein the registration acceptance is used for indicating that the AMF accepts the registration request of the UE, and the registration rejection is used for indicating that the AMF rejects the registration request of the UE. Illustratively, the N2 message is Downlink NAS Transport, and the registration accept and registration reject are NAS messages, for example, registration accept is registration accept and registration reject is registration reject.

Optionally, the AMF sends registration accept or registration reject to the UE by sending an N2 message to the NG-RAN1, depending on whether an intra-system handover or release is required for the UE. Illustratively, when the AMF includes the acceptance indication information in the handover response message received at step S1113 or includes the handover indication information in the received release response message, the AMF transmits a registration acceptance message to the UE by transmitting an N2 message to the NG-RAN 1. When the AMF includes the rejection indication information in the handover response message received at S1113 or includes the release indication information in the received release response message, the AMF transmits a registration rejection message to the UE by transmitting an N2 message to the NG-RAN 1.

Optionally, step S1115 is further included, in which the NG-RAN1 transmits registration acceptance or rejection of the UE received from the AMF to the UE.

As can be seen from the above description, in this example 4, when the UE is handed over from the EPS to the NG-RAN1 in the 5GS and the NG-RAN1 does not support CAG subscription of the UE, after receiving the registration request of the UE, the AMF may determine that the UE needs to perform handover or release in the 5GS after completing the handover according to the first indication information previously received from the NG-RAN1, further send a handover request message or a release request message to the NG-RAN1 and carry CAG subscription of the terminal device, and the NG-RAN1 decides whether to initiate a handover procedure or a release procedure in the 5GS according to the CAG subscription of the terminal device, thereby facilitating handover of the terminal device to another NG-RAN in the 5GS that supports CAG subscription thereof.

Please refer to fig. 12, which is a flowchart illustrating another access control method according to an embodiment of the present application, where the method is applied in a scenario where a terminal device is switched from a second communication system to a first communication system. Illustratively, the first communication system is a 5G communication system (i.e., 5GS), the second communication system is a 4G communication system (i.e., EPS), although the first communication system and the second communication system may also be other communication systems, and the present application is not limited thereto.

The method comprises the following steps:

step S1201, the MME sends a forwarding redirection request to the AMF, where the forwarding redirection request is used to request to redirect the terminal device to the AMF.

Accordingly, the AMF receives a forward redirection request from the MME.

Step S1202, the AMF obtains the CAG subscription of the terminal equipment.

Step S1203, the AMF sends a handover request to the first access network device, where the handover request is used to request to handover the terminal device to the first access network device, and the handover request includes a CAG subscription of the terminal device.

Step S1204, if the first access network device does not support CAG subscription of the terminal device, the first access network device sends a handover request response to the AMF, where the handover request response is used to indicate that the handover request is accepted, and the handover request response includes first indication information used to indicate that the terminal device needs to perform intra-system handover or release subsequently.

For the specific implementation of the above steps S1201 to S1204, please refer to the above description related to the steps S1001 to S1004, which is not repeated herein.

Step S1205, the first access network device initiates an intra-system handover or release process.

In this embodiment, the first access network device may initiate an intra-system handover or release procedure after sending the fourth message to the AMF. The fourth message is used for notifying the AMF terminal device of completion of handover, or the fourth message includes a registration request of the terminal device, where the registration request is used for requesting registration to the first communication system. Optionally, the fourth message includes cell CAG capability information of the first access network device.

As can be seen from the above, the embodiment shown in fig. 12 specifically relates to a cross-system handover process of a terminal device from a second communication system to a first communication system and a registration process after the handover is completed.

Similar to the above related flow two (i.e., the embodiment shown in fig. 10), in the cross-system handover process of the terminal device from the second communication system to the first communication system, the AMF in the first communication system may acquire the CAG subscription of the terminal device, and send the CAG subscription of the terminal device and the handover request together to the first access network device in the first communication system. After receiving the CAG subscription and the switching request of the terminal device, the first access network device may determine whether it supports the CAG subscription of the terminal device. If the CAG subscription of the terminal device is not supported, the first access network device may still accept the handover request, but locally record that intra-system handover or release is subsequently required and notify the AMF.

However, the difference is that the first access network device may actively initiate an intra-system handover or release procedure according to the first indication information after the handover procedure of the terminal device is completed (i.e. when the sent fourth message is a handover notification message) or when the registration procedure of the terminal device is started (i.e. when the sent fourth message includes a registration request message).

Optionally, after the first access network device sends the handover request response to the AMF, a series of handover procedures need to be performed. Therefore, the first access network device may set a flag information (flag) in the memory after determining that the terminal device needs to perform intra-system handover or release subsequently, so as to remind the first access network device to initiate an intra-system handover or release procedure after the terminal device completes handover or when a registration process starts. The flag information may be cleared at the initiating system for handover or release procedures.

Please refer to fig. 13, which is a flowchart illustrating another access control method according to an embodiment of the present disclosure, where the method is applied in a scenario where a terminal device is switched from a second communication system to a first communication system. Illustratively, the first communication system is a 5G communication system (i.e., 5GS), the second communication system is a 4G communication system (i.e., EPS), although the first communication system and the second communication system may also be other communication systems, and the present application is not limited thereto.

It should be noted that, compared with the related flow chart two (i.e., the embodiment shown in fig. 10) and the embodiment shown in fig. 12, the embodiment shown in fig. 13 mainly differs in that: after the first access network device receives the handover request from the AMF, if it is determined that the CAG subscription of the terminal device is not supported (or further the terminal device has an ongoing session associated with the PNI-NPN), the first access network device may reject the handover request, send a handover request response to the AMF, and carry a cause value (i.e., a reject cause or a handover failure cause) in the handover request response. And then, the AMF can return the reason value to the MME, and the MME selects new target access network equipment according to the reason value to reinitiate the switching. Optionally, the first access network device may further carry information of the candidate access network device in the handover request response, so that the MME may consider the candidate access network device provided by the first access network device when selecting a new target access network device.

The method comprises the following steps:

step S1301, the MME sends a forwarding redirection request to the AMF, where the forwarding redirection request is used to request to redirect the terminal device to the AMF.

Accordingly, the AMF receives a forward redirection request from the MME.

Step S1302, the AMF obtains the CAG subscription of the terminal equipment.

Step S1303, the AMF sends a handover request to the first access network device, where the handover request is used to request to handover the terminal device to the first access network device, and the handover request includes a CAG subscription of the terminal device.

For the specific implementation of steps S1301 to S1303, please refer to the above description about steps S1001 to S1003, and will not be described again.

Step S1304, if the first access network device does not support the CAG subscription of the terminal device, the first access network device sends a handover request response to the AMF, where the handover request response is used to indicate that the handover request is rejected, and the handover request response includes a cause value, where the cause value is used to indicate that the CAG subscription of the terminal device is not supported, or the CAG subscription of the terminal device is not satisfied.

Optionally, the first access network device may further determine, according to the CAG subscription of the terminal device, a candidate access network device supporting the CAG subscription of the terminal device in the first communication system, and send the AMF by carrying information of the candidate access network device in the handover request response. The candidate access network device refers to a candidate target access network device, that is, a target access network device selectable in the first communication system and selected by the first access network device as the terminal device. The number of the candidate access network devices may be one or more, and the application is not limited thereto.

Step S1305, the AMF sends a forwarding redirection response to the MME, where the forwarding redirection response includes the cause value.

Accordingly, the MME receives the forward redirection response from the AMF.

Optionally, the forwarding redirection response further includes information of the candidate access network device.

Further, the MME may send a handover failure message to the third access network device, where the handover failure message includes the cause value. Optionally, the handover failure message further includes information of the candidate access network device. The handover failure message may also be referred to as a handover preparation failure message or have another name, and the application is not limited thereto.

In this way, after the third access network device receives the handover failure message from the MME, a new target access network device may be selected according to the cause value, and the handover may be performed again. Optionally, when selecting a new target access network device, the third access network device may consider a candidate access network device provided by the first access network device, for example, the candidate access network device may be used as the new target access network device.

Please refer to fig. 14, which is a flowchart illustrating another access control method according to an embodiment of the present disclosure, where the method is applied in a scenario where a terminal device is switched from a second communication system to a first communication system. Illustratively, the first communication system is a 5G communication system (i.e., 5GS), and the second communication system is a 4G communication system (i.e., EPS), although the first communication system and the second communication system may be other communication systems, and the present application is not limited thereto.

It should be noted that, compared with the related flow two (i.e., the embodiment shown in fig. 10), the embodiment shown in fig. 12, and the embodiment shown in fig. 13, the embodiment shown in fig. 14 mainly differs in that: before the third access network device executes a handover initialization process and triggers the terminal device to handover from the second communication system to the first communication system, the MME may obtain the CAG subscription of the terminal device from the UDM and store the CAG subscription of the terminal device in the context of the terminal device. Thus, when the MME sends a forward redirection request to the AMF, since the context of the terminal device already includes the CAG subscription of the terminal device, the AMF does not need to separately obtain the CAG subscription of the terminal device from the UDM. The UDM may refer to a HSS + UDM network element.

The method comprises the following steps:

step S1401, the MME acquires the CAG subscription of the terminal device.

In this embodiment of the application, the process of acquiring the CAG subscription of the terminal device by the MME may refer to the description of acquiring the CAG subscription of the terminal device by the AMF introduced in fig. 5, which is not repeated.

Step S1402, the MME stores the CAG subscription of the terminal device in the context of the terminal device.

After the MME acquires the CAG subscription of the terminal device, the acquired CAG subscription of the terminal device may not be sent to the third access network device. Optionally, the MME may also send the acquired CAG subscription of the terminal device to the third access network device.

If the MME selects to send the CAG subscription of the terminal device to the third access network device, the third access network device may select the target access network device in the first communication system according to the CAG subscription of the terminal device when triggering the terminal device to perform the cross-system handover. However, the target access network device in the first communication system selected by the third access network device may be an access network device supporting CAG subscription of the terminal device, or may be an access network device not supporting CAG subscription of the terminal device, and the application is not limited.

It should be noted that, if the subsequent flow is implemented based on the method in the embodiment shown in fig. 13, that is, the first access network device selects to reject the handover request when the CAG subscription of the terminal device is not supported, the handover request response sent by the first access network device to the AMF, the forwarding redirection response sent by the AMF to the MME, and the handover failure message sent by the MME to the third access network device only include cause values, which are used to indicate that the cause of the handover failure is not satisfied by the CAG subscription of the terminal device, and do not need to include information of the candidate access network device.

Step S1403, the third access network device executes a handover initialization procedure to trigger the terminal device to handover from the second communication system to the first communication system.

Step S1404, the third access network device sends a handover request to the MME, where the handover request is used to request that the terminal device be handed over to the first communication system.

Accordingly, the MME receives a handover request from the third access network device.

Step S1405, the MME sends a forward redirection request to the AMF, where the forward redirection request is used to request that the terminal device be redirected to the AMF.

Correspondingly, the AMF receives a forwarding redirection request from the MME, wherein the forwarding redirection request comprises the CAG subscription of the terminal equipment.

Step S1406, the AMF sends a handover request to the first access network device, where the handover request is used to request that the terminal device be handed over to the first access network device, and the handover request includes a CAG subscription of the terminal device.

The process after step S1406 may be implemented based on the above-described related process two, the embodiment shown in fig. 12, or the method after the first access network device receives the handover request from the AMF in the embodiment shown in fig. 13, and is not described again. That is, the first access network device may choose to accept the handover request when the CAG subscription of the terminal device is not supported, or may choose to reject the handover request. Moreover, when the first access network device does not support the CAG subscription of the terminal device, the subsequent intra-system handover or release process may be initiated under the indication or request of the AMF, or may be initiated actively by the first access network device, all without limitation.

Please refer to fig. 15, which is a flowchart illustrating a further access control method according to an embodiment of the present application, where the method is applied to a scenario in which a terminal device is switched from a first communication system to a second communication system. Illustratively, the first communication system is a 5G communication system (i.e., 5GS), and the second communication system is a 4G communication system (i.e., EPS), although the first communication system and the second communication system may be other communication systems, and the present application is not limited thereto.

The method comprises the following steps:

step S1501, the first access network device triggers the terminal device to switch from the first communication system to a target access network device in the second communication system, and when the target access network device is selected, the CAG subscription of the UE is not considered.

Step S1502, the first access network device sends a handover request to the AMF, where the handover request is used to request to handover the terminal device to a target access network device in the second communication system.

Accordingly, the AMF receives a handover request from the first access network device.

Optionally, the handover request may include handover type information, where the handover type information is used to indicate handover from the first communication system to the second communication system.

Alternatively, the AMF may obtain the terminal device context after receiving a handover request from the first access network device.

Step S1503, the AMF sends a forwarding redirection request to the MME, where the forwarding redirection request is used to redirect the terminal device to the MME, and the forwarding redirection request does not include the CAG subscription of the terminal device.

Accordingly, the MME receives a forward redirection request from the AMF.

Optionally, the forwarding redirection request includes a context of the terminal device, but the context of the terminal device does not include the CAG subscription of the terminal device.

Optionally, the AMF may determine, according to the handover type information, that the CAG subscription of the terminal device is not carried in the forwarding redirection request.

After the MME receives the forwarding redirection request from the AMF, the MME may continue to perform a handover procedure of the terminal device, and handover the terminal device to a target access network device in the second communication system, without considering the CAG subscription of the terminal device in this procedure.

In a possible embodiment, the forwarding redirection request sent by the AMF to the MME may also include a CAG subscription of the terminal device, but in a subsequent handover procedure, the MME ignores the CAG subscription of the terminal device according to that the handover from the first communication system to the second communication system is currently performed.

As can be seen from the above description, in the embodiment shown in fig. 15, when the terminal device is switched from the first communication system to the second communication system, the first access network device (source access network device) may not consider the CAG subscription of the terminal device when triggering the switching, the AMF may not carry the CAG subscription of the terminal device or carry the CAG subscription of the terminal device in the forwarding redirection request sent to the MME, but the MME ignores the CAG subscription of the terminal device according to the currently performed switching from the first communication system to the second communication system. Therefore, the CAG subscription of the terminal equipment is not considered by the source side and the target side in the switching process of the terminal equipment from the first communication system to the second communication system, so that the switching process is simplified, and the efficiency is improved.

Referring to fig. 16, a schematic structural diagram of a communication device provided in an embodiment of the present application is shown, where the communication device 1600 includes: a transceiver module 1610 and a processing module 1620. The communication device may be configured to implement the functions related to the network device (such as the access and mobility management functions or the functions of the first access network device) in any of the above method embodiments. The communication means may be a network device or a chip or a circuit comprised in a network device.

Illustratively, when the communication apparatus performs the operation or step corresponding to the access and mobility management function in the method embodiment shown in fig. 4, the transceiving module 1610 is configured to acquire a CAG subscription of a terminal device, which is handed over from the second communication system to the first access network device of the first communication system; the processing module 1620 is configured to instruct, through the transceiver module 1610, a first access network device to initiate an intra-system handover or release procedure, where the first access network device does not support the CAG subscription of the terminal device.

In one possible design, the terminal device has an ongoing session associated with PNI-NPN information, which includes S-NSSAI and/or DNN.

In one possible design, the CAG subscription of the terminal device is used to indicate an identity of one or more CAGs allowed by the terminal device and/or whether the terminal device is only allowed to access the first communication system through a CAG cell.

In one possible design, the transceiver module 1610 is configured to receive cell CAG capability information from the first access network device, where the cell CAG capability information is used to indicate whether a cell of the first access network device supports a CAG function, and if so, the cell CAG capability information is also used to indicate an identifier of one or more CAGs supported by the cell; the processing module 1620 is further configured to determine whether the first access network device supports CAG subscription of the terminal device according to the cell CAG capability information.

In one possible design, the first access network device does not support CAG subscription for the terminal device, comprising: a cell of first access network equipment supports a CAG function, but the identification of one or more CAGs supported by the cell is not the identification of a CAG allowed by terminal equipment; or, the cell of the first access network device does not support the CAG function, but the terminal device only allows access to the first communication system through the CAG cell.

In one possible design, the transceiver module 1610 is configured to receive a first message from a first access network device, where the first message includes a registration request of a terminal device, where the registration request is used to request registration to a first communication system, and the registration request includes mobility information, where the mobility information indicates that the terminal device is from a second communication system; the processing module 1620 is specifically configured to instruct, according to the mobility information, the first access network device to initiate an intra-system handover or release procedure.

In one possible design, the first message includes cell CAG capability information of the first access network device.

In a possible design, the processing module 1620 is specifically configured to send, according to the mobility information, a second message to the first access network device through the transceiver module 1610, where the second message is used to indicate or request an intra-system handover or release of the terminal device, and the second message includes a CAG subscription of the terminal device.

In one possible design, a cause value is included in the second message, and the cause value is used for indicating that CAG subscription of the terminal device is not supported.

In a possible design, the processing module 1620 is specifically configured to send, according to the mobility information, a third message to the first access network device through the transceiver module 1510, where the third message includes a registration accept and a CAG subscription of the terminal device, and the registration accept is used to indicate that the registration request of the terminal device is accepted.

In a possible design, the transceiving module 1610 is further configured to receive a forward redirection request from the mobility management entity, where the forward redirection request is used to request that the terminal device be redirected to the access and mobility management functions; sending a switching request to first access network equipment, wherein the switching request is used for requesting to switch the terminal equipment to the first access network equipment, and the switching request comprises CAG (computer aided generation) subscription of the terminal equipment; receiving a handover request response from the first access network device, where the handover request response is used to indicate that the handover request is accepted, the handover request response includes first indication information, and the first indication information is used to indicate that the terminal device needs to perform intra-system handover or release subsequently; the processing module 1620 is specifically configured to instruct, through the transceiving module 1610, the first access network device to initiate an intra-system handover or release procedure according to the first indication information.

In one possible design, the handover request includes handover type information indicating handover from the second communication system to the first communication system.

In one possible design, the transceiver module 1610 is specifically configured to, if the processing module 1620 determines that the terminal device has an ongoing session associated with PNI-NPN information, or that the usage type of the terminal device is a specific usage type, acquire a CAG subscription of the terminal device from unified data management, where the PNI-NPN information includes specific S-NSSAI and/or DNN.

In a possible design, the transceiving module 1610 is further configured to receive a fourth message from the first access network device, where the fourth message is used to notify the access and mobility management function that the terminal device is handed over, or the fourth message includes a registration request of the terminal device, where the registration request is used to request to register to the first communication system; the processing module 1620 is specifically configured to send, according to the first indication information, a fifth message to the first access network device through the transceiver module 1610, where the fifth message is used to indicate or request an intra-system handover or release of the terminal device, and the fifth message includes a cause value, where the cause value is used to indicate that the CAG subscription of the terminal device is not supported.

In one possible design, the fifth message includes cell CAG capability information of the first access network device.

In a possible design, the transceiving module 1610 is further configured to receive a sixth message from the first access network device, where the sixth message is used to notify the access and mobility management function to wait for the subsequent first access network device to trigger the intra-system handover procedure, or is used to notify the access and mobility management function to trigger the release procedure or wait for the first access network device to trigger the release procedure.

In one possible design, the transceiving module 1610 is further configured to send a seventh message to the first access network device; if the sixth message is used to notify the access and mobility management function to wait for the subsequent first access network device to trigger the intra-system handover procedure, the seventh message includes a registration acceptance, and the registration acceptance is used to indicate to accept the registration request of the terminal device; if the sixth message is used to notify the access and mobility management function to trigger the release procedure or wait for the first access network device to trigger the access network release procedure, the seventh message includes a registration rejection, and the registration rejection is used to indicate that the registration request of the terminal device is rejected.

When the communication apparatus performs the operation or step corresponding to the first access network device in the method embodiment shown in fig. 4, the transceiver module 1610 is configured to receive an indication from the access and mobility management function, where the first access network device does not support CAG subscription of the terminal device, and the terminal device is handed over from the second communication system to the first access network device; the processing module 1620 is configured to initiate an intra-system handover or release procedure according to the indication.

In a possible design, the transceiver module 1610 is further configured to send cell CAG capability information to the access and mobility management function, where the cell CAG capability information is used to indicate whether a cell of the first access network device supports a CAG function, and if so, the cell CAG capability information is also used to indicate an identifier of one or more CAGs supported by the cell.

In one possible design, the first access network device does not support CAG subscription of the terminal device, and the method includes: a cell of first access network equipment supports a CAG function, but the identification of one or more CAGs supported by the cell is not the identification of a CAG allowed by terminal equipment; or, the cell of the first access network device does not support the CAG function, but the terminal device only allows access to the first communication system through the CAG cell.

In one possible design, the transceiver module 1610 is further configured to send a first message to the access and mobility management function, where the first message includes a registration request of the terminal device, the registration request is used to request registration to the first communication system, and the registration request includes mobility information, and the mobility information indicates that the terminal device is from the second communication system.

In a possible design, the transceiving module 1610 is further configured to receive a second message from the access and mobility management function, where the second message is used to indicate or request an intra-system handover or release of the terminal device, and the second message includes a CAG subscription of the terminal device.

In one possible design, the transceiver module 1610 is further configured to receive a third message from the access and mobility management function, where the third message includes a registration accept and a CAG subscription of the terminal device, and the registration accept indicates that the registration request of the terminal device is accepted.

In a possible design, the transceiving module 1610 is further configured to receive a handover request from the access and mobility management function, where the handover request is used to request that the terminal device is handed over to the first access network device, and the handover request includes a CAG subscription of the terminal device; and if the processing module 1620 determines that the CAG subscription of the terminal device is not supported, send a handover request response to the access and mobility management function, where the handover request response is used to indicate that the handover request is accepted, and the handover request response includes first indication information, where the first indication information is used to indicate that the terminal device needs to perform intra-system handover or release subsequently.

In one possible design, the handover request includes handover type information indicating handover from the second communication system to the first communication system; the transceiver module 1610 is specifically configured to send a handover request response to the access and mobility management function according to the handover type information.

In a possible design, the transceiving module 1610 is further configured to send a fourth message to the access and mobility management function, where the fourth message is used to notify the access and mobility management function that the handover of the terminal device is completed, or the fourth message includes a registration request of the terminal device, where the registration request is used to request to register to the first communication system; and receiving a fifth message from the access and mobility management function, wherein the fifth message is used for indicating or requesting intra-system handover or release of the terminal equipment, and the fifth message comprises a cause value, and the cause value is used for indicating that the CAG subscription of the terminal equipment is not supported.

In one possible design, the fourth message includes cell CAG capability information of the first access network device.

In a possible design, the transceiving module 1610 is further configured to send a sixth message to the access and mobility management function, where the sixth message is used to notify the access and mobility management function to wait for the subsequent first access network device to trigger an intra-system handover procedure, or to notify the access and mobility management function to trigger a release procedure or wait for the first access network device to trigger a release procedure.

In one possible design, the transceiver module 1610 is further configured to receive a seventh message from the access and mobility management function; if the sixth message is used for notifying the access and mobility management function to wait for the subsequent first access network equipment to trigger the switching process in the system, the seventh message comprises registration acceptance which is used for indicating to accept the registration request of the terminal equipment; if the sixth message is used to notify the access and mobility management function to trigger the release process or wait for the first access network device to trigger the release process, the seventh message includes a registration rejection, and the registration rejection is used to indicate to reject the registration request of the terminal device.

In a possible design, the processing module 1620 is specifically configured to, according to the CAG subscription of the terminal device, initiate an intra-system handover procedure if a second access network device supporting the CAG subscription is found, and otherwise initiate a release procedure.

The processing module 1620 may be implemented by at least one processor or processor-related circuit component, and the transceiver module 1610 may be implemented by at least one transceiver or transceiver-related circuit component or communication interface. The operations and/or functions of the modules in the communication apparatus are respectively for implementing the corresponding flows of the methods shown in fig. 4 to fig. 15, and are not described herein again for brevity. Optionally, the communication device may further include a storage module, which may be configured to store data and/or instructions, and the transceiver module 1610 and/or the processing module 1620 may read the data and/or instructions in the access module, so as to enable the communication device to implement the corresponding method. The memory module may be implemented, for example, by at least one memory.

The storage module, the processing module and the transceiver module may be separated, or all or part of the modules may be integrated, for example, the storage module and the processing module are integrated, or the processing module and the transceiver module are integrated.

Please refer to fig. 17, which is a schematic structural diagram of a communication device according to an embodiment of the present application. The communication device may be a network device or a device capable of supporting the network device to implement the corresponding function in the foregoing method embodiment, and the like.

The communication device may include a processor 1701, a communication interface 1702, and a memory 1703. The communication interface 1702 is used for communicating with other devices through a transmission medium, and the communication interface 1702 may be a transceiver, and may also be an interface circuit such as a transceiver circuit, a transceiver chip, and the like. The memory 1703 is used to store program instructions and/or data, and the processor 1701 is used to execute the program instructions stored in the memory 1703, thereby implementing the methods in the above-described method embodiments. Optionally, the memory 1703 is coupled to the processor 1701, and the coupling is an indirect coupling or communication connection between devices, units or modules, which may be electrical, mechanical or other, for information exchange between the devices, units or modules.

In one embodiment, the communication interface 1702 may be specifically configured to perform the actions of the transceiver 1610, and the processor 1701 may be specifically configured to perform the actions of the processing module 1620, which will not be described herein again.

The embodiment of the present application does not limit the specific connection medium among the communication interface 1702, the processor 1701, and the memory 1703. In the embodiment of the present application, the memory 1703, the processor 1701, and the communication interface 1702 are connected by the bus 1704 in fig. 17, the bus is indicated by a thick line in fig. 17, and the connection manner between other components is merely illustrative and not limited. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown in FIG. 17, but this does not mean only one bus or one type of bus.

Please refer to fig. 18, which is a schematic structural diagram of a communication device according to an embodiment of the present application. The communication device may be configured to implement the functionality relating to the first access network device in any of the above method embodiments. The communication device is embodied as a network device, such as a base station.

The network device 1800 includes: one or more DUs 1801 and one or more CUs 1802. The DU 1801 may include at least one antenna 18011, at least one radio frequency unit 18012, at least one processor 18013, and at least one memory 18014. The DU 1701 is mainly used for transceiving radio frequency signals, converting radio frequency signals to baseband signals, and partially processing baseband.

The CU 1802 may include at least one processor 18022 and at least one memory 18021. The CU 1802 is mainly used to perform baseband processing, control a base station, and the like. The CU 1802 is the control center of the base station and may also be referred to as a processing unit. For example, the CU 1802 may be configured to control the base station to perform operations or steps corresponding to those described above with respect to the first access network device in the methods shown in fig. 4 through 15.

The CU 1802 and the DU 1801 may communicate with each other through an interface, where a Control Plane (CP) interface may be Fs-C, such as F1-C, and a User Plane (UP) interface may be Fs-U, such as F1-U. The DU 1801 and the CU 1802 may be physically disposed together or disposed separately (i.e., distributed base stations), and are not limited thereto.

Specifically, the baseband processing on the CU and the DU may be divided according to the protocol layers of the radio network, for example, the functions of the PDCP layer and the above protocol layers are set in the CU, and the functions of the protocol layers below the PDCP layer (for example, the RLC layer and the MAC layer, etc.) are set in the DU. For another example, a CU implements functions of an RRC and PDCP layer, and a DU implements functions of an RLC, MAC, and Physical (PHY) layer.

Alternatively, network device 1800 may include one or more Radio Units (RUs), one or more DUs, and one or more CUs. Wherein a DU may include at least one processor 18013 and at least one memory 18014, an RU may include at least one antenna 18011 and at least one radio frequency unit 18012, and a CU may include at least one processor 18022 and at least one memory 18021.

In an embodiment, the CU 1802 may be formed by one or more boards, where the multiple boards may collectively support a radio access network with a single access indication (e.g., a 5G network), or may respectively support radio access networks with different access schemes (e.g., an LTE network, a 5G network, or other networks). The memory 18021 and the processor 18022 may serve one or more boards. That is, the memory and processor may be provided separately on each board. Multiple boards may share the same memory and processor. In addition, each single board can be provided with necessary circuits.

The DU 1801 may be formed by one or multiple boards, and the multiple boards may jointly support a radio access network with a single access instruction (e.g., a 5G network), and may also respectively support radio access networks with different access schemes (e.g., an LTE network, a 5G network, or other networks). The memory 18014 and the processor 18013 may serve one or more boards. That is, the memory and processor may be provided separately on each board. Multiple boards may share the same memory and processor. In addition, each single board can be provided with necessary circuits.

An embodiment of the present application further provides a chip system, including: a processor coupled with a memory for storing a program or instructions which, when executed by the processor, cause the system-on-chip to implement the corresponding mobility management functionality or method of the first access network device in any of the above method embodiments.

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

Optionally, the memory in the system-on-chip may also be one or more. The memory may be integrated with the processor or may be separate from the processor, which is not limited in this application. For example, the memory may be a non-transitory processor, such as a read only memory ROM, which may be integrated on the same chip as the processor, or may be separately disposed on different chips, and the type of the memory and the arrangement of the memory and the processor are not particularly limited in this application.

The system-on-chip may be, for example, a Field Programmable Gate Array (FPGA), an Application Specific Integrated Circuit (ASIC), a system on chip (SoC), a Central Processing Unit (CPU), a Network Processor (NP), a digital signal processing circuit (DSP), a Microcontroller (MCU), a Programmable Logic Device (PLD), or other integrated chips.

It should be understood that the steps of the above method embodiments may be performed by integrated logic circuits of hardware in a processor or instructions in the form of software. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in a processor.

The embodiment of the present application further provides a computer-readable storage medium, where computer-readable instructions are stored in the computer-readable storage medium, and when the computer-readable instructions are read and executed by a computer, the computer is enabled to execute the method in any of the above method embodiments.

The embodiments of the present application further provide a computer program product, which when read and executed by a computer, causes the computer to execute the method in any of the above method embodiments.

The embodiment of the application also provides a communication system, which comprises an access and mobility management function and the first access network equipment. Optionally, the communication system further includes a second access network device, and the second access network device also belongs to the first communication system. In one possible design, the communication system further includes a mobility management entity and a third access network device, where the mobility management entity and the third access network device belong to the second communication system.

The access and mobility management function, the first access network device, the mobility management entity, and the third access network device may cooperate with each other to implement the method in any of the above method embodiments.

Illustratively, the first communication system is a fifth generation communication system 5GS, and the second communication system is a packet evolution system EPS. The first access network device and the second access network device may be a next generation radio access network node/base station NG-RAN in a fifth generation communication system 5GS and the third access network device may be an evolved universal terrestrial radio access network node/base station E-UTRAN in a packet evolution system EPS.

It should be understood that the processor referred to in the embodiments of the present application may be a CPU, but may also be other general purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

It will also be appreciated that the memory referred to in the embodiments of the application may be either volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. The non-volatile memory may be a read-only memory (ROM), a programmable ROM, an erasable programmable ROM, an electrically erasable programmable ROM, or a flash memory. Volatile memory can be Random Access Memory (RAM), which acts as external cache memory. By way of example, and not limitation, many forms of RAM are available, such as static random access memory, dynamic random access memory, synchronous dynamic random access memory, double data rate synchronous dynamic random access memory, enhanced synchronous dynamic random access memory, synchronous link dynamic random access memory, and direct memory bus random access memory.

It should be noted that when the processor is a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, the memory (memory module) is integrated in the processor.

It should be noted that the memory described herein is intended to comprise, without being limited to, these and any other suitable types of memory.

It should be understood that the various numerical references mentioned in the various embodiments of the present application are merely for convenience of description and differentiation, and the serial numbers of the above-mentioned processes or steps do not imply any order of execution, and the execution order of the processes or steps should be determined by their functions and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a U disk, a removable hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

In the embodiments of the present application, unless otherwise specified or conflicting with respect to logic, the terms and/or descriptions in different embodiments have consistency and may be mutually cited, and technical features in different embodiments may be combined to form a new embodiment according to their inherent logic relationship.

Claims

1. An access control method, the method comprising:

the access and mobility management function of a first communication system acquires a Closed Access Group (CAG) subscription of terminal equipment, and the terminal equipment is switched to first access network equipment of the first communication system from a second communication system;

and the access and mobility management function indicates the first access network equipment to initiate an intra-system handover or release process, and the first access network equipment does not support the CAG subscription of the terminal equipment.

2. Method according to claim 1, characterized in that the terminal device has an ongoing session associated with public network integrated non-public network PNI-NPN information comprising specific single network slice selection assistance information S-NSSAI and/or data network name DNN.

3. The method according to claim 1 or 2, wherein the CAG subscription of the terminal device is used to indicate the identity of one or more CAGs allowed by the terminal device and/or whether the terminal device is only allowed to access the first communication system through a CAG cell.

4. The method according to any one of claims 1 to 3, further comprising:

the access and mobility management function receives cell CAG capability information from the first access network equipment, wherein the cell CAG capability information is used for indicating whether a cell of the first access network equipment supports a CAG function, and if so, the cell CAG capability information is also used for indicating one or more CAG identifiers supported by the cell;

and the access and mobility management function judges whether the first access network equipment supports the CAG subscription of the terminal equipment or not according to the CAG capability information of the cell.

5. The method of claim 4, wherein the first access network device does not support CAG subscription of the terminal device, and wherein the method comprises:

the cell of the first access network device supports the CAG function, but the identification of one or more CAGs supported by the cell is not the identification of the CAG allowed by the terminal device; or the like, or, alternatively,

the cell of the first access network device does not support the CAG function, but the terminal device only allows access to the first communication system through the CAG cell.

6. The method according to any one of claims 1 to 5, further comprising:

the access and mobility management function receives a first message from the first access network device, where the first message includes a registration request of the terminal device, where the registration request is used to request registration to the first communication system, and the registration request includes mobility information indicating that the terminal device is from the second communication system;

the access and mobility management function instructing the first access network device to initiate an intra-system handover or release procedure, including:

and the access and mobility management function instructs the first access network equipment to initiate an intra-system handover or release process according to the mobility information.

7. The method of claim 6, wherein the accessing and mobility management function instructs the first access network device to initiate an intra-system handover or release procedure according to the mobility information, comprising:

and the access and mobility management function sends a second message to the first access network device according to the mobility information, wherein the second message is used for indicating or requesting intra-system switching or release of the terminal device, and the second message comprises a CAG subscription of the terminal device.

8. The method of claim 7, wherein a cause value is included in the second message, and wherein the cause value is used to indicate that the CAG subscription of the terminal device is not supported.

9. The method of claim 6, wherein the accessing and mobility management function instructs the first access network device to initiate an intra-system handover or release procedure according to the mobility information, comprising:

and the access and mobility management function sends a third message to the first access network device according to the mobility information, wherein the third message comprises registration acceptance and CAG subscription of the terminal device, and the registration acceptance is used for indicating to accept the registration request of the terminal device.

10. The method according to any one of claims 1 to 5, further comprising:

the access and mobility management function receives a forwarding redirection request from a mobility management entity, wherein the forwarding redirection request is used for requesting to redirect the terminal equipment to the access and mobility management function;

the access and mobility management function sends a switching request to the first access network device, wherein the switching request is used for requesting to switch the terminal device to the first access network device, and the switching request comprises a CAG subscription of the terminal device;

the access and mobility management function receives a handover request response from the first access network device, where the handover request response is used to indicate that the handover request is accepted, the handover request response includes first indication information, and the first indication information is used to indicate that the terminal device needs to perform intra-system handover or release subsequently;

and the access and mobility management function instructs the first access network equipment to initiate an intra-system handover or release process according to the first indication information.

11. The method of claim 10, wherein the handover request includes handover type information, and wherein the handover type information is used for indicating handover from the second communication system to the first communication system.

12. The method according to claim 10 or 11, further comprising:

the access and mobility management function receives a fourth message from the first access network device, where the fourth message is used to notify the access and mobility management function that the terminal device is completed in handover, or the fourth message includes a registration request of the terminal device, where the registration request is used to request registration to the first communication system;

the accessing and mobility management function instructs the first access network device to initiate an intra-system handover or release procedure according to the first indication information, including:

and the access and mobility management function sends a fifth message to the first access network device according to the first indication information, wherein the fifth message is used for indicating or requesting intra-system handover or release of the terminal device, and the fifth message comprises a cause value which is used for indicating that CAG subscription of the terminal device is not supported.

13. The method of any one of claims 7, 8 or 12, further comprising:

the access and mobility management function receives a sixth message from the first access network device, where the sixth message is used to notify the access and mobility management function to wait for the subsequent initiation of an intra-system handover procedure by the first access network device, or to notify the access and mobility management function to initiate a release procedure or wait for the initiation of a release procedure by the first access network device.

14. The method of claim 13, further comprising:

the access and mobility management function sending a seventh message to the first access network device;

if the sixth message is used to notify the access and mobility management function to wait for the subsequent triggering of the intra-system handover procedure by the first access network device, the seventh message includes a registration acceptance, and the registration acceptance is used to indicate acceptance of the registration request of the terminal device;

if the sixth message is used to notify the access and mobility management function to trigger a release procedure or wait for the first access network device to trigger a release procedure, the seventh message includes a registration rejection, and the registration rejection is used to indicate that the registration request of the terminal device is rejected.

15. An access control method, the method comprising:

a first access network device of a first communication system receives an indication from an access and mobility management function, the first access network device does not support CAG (closed access group) subscription of a terminal device, and the terminal device is switched to the first access network device from a second communication system;

and the first access network equipment initiates an intra-system switching or releasing process according to the indication.

16. The method according to claim 15, wherein the CAG subscription of the terminal device is used to indicate an identity of one or more CAGs allowed by the terminal device and/or whether the terminal device is only allowed to access the first communication system through a CAG cell.

17. The method according to claim 15 or 16, further comprising:

the first access network equipment sends cell CAG capability information to the access and mobility management function, the cell CAG capability information is used for indicating whether the cell of the first access network equipment supports the CAG function, and if the cell CAG capability information supports the CAG function, the cell CAG capability information is also used for indicating one or more CAG identifiers supported by the cell.

18. The method of any of claims 15 to 17, wherein the first access network device does not support CAG subscription for the terminal device, comprising:

the cell of the first access network device supports the CAG function, but the identification of one or more CAGs supported by the cell is not the identification of the CAG allowed by the terminal device; or the like, or a combination thereof,

19. The method according to any one of claims 15 to 18, further comprising:

the first access network device sends a first message to the access and mobility management function, where the first message includes a registration request of the terminal device, the registration request is used to request registration to the first communication system, the registration request includes mobility information, and the mobility information indicates that the terminal device is from the second communication system.

20. The method of claim 19, wherein the first access network device receiving an indication from an access and mobility management function, comprises:

and the first access network equipment receives a second message from the access and mobility management function, wherein the second message is used for indicating or requesting the terminal equipment to perform intra-system handover or release, and the second message comprises the CAG subscription of the terminal equipment.

21. The method of claim 20, wherein a cause value is included in the second message, and wherein the cause value is used to indicate that CAG subscription of the terminal device is not supported.

22. The method of claim 19, wherein the first access network device receives an indication from an access and mobility management function, comprising:

and the first access network equipment receives a third message from the access and mobility management function, wherein the third message comprises registration acceptance and CAG subscription of the terminal equipment, and the registration acceptance is used for indicating to accept the registration request of the terminal equipment.

23. The method according to any one of claims 15 to 18, further comprising:

the first access network equipment receives a switching request from the access and mobility management function, wherein the switching request is used for requesting to switch the terminal equipment to the first access network equipment, and the switching request comprises a CAG subscription of the terminal equipment;

and if the first access network equipment judges that the CAG subscription of the terminal equipment is not supported, sending a switching request response to the access and mobility management function, wherein the switching request response is used for indicating to accept the switching request, the switching request response comprises first indication information, and the first indication information is used for indicating that the terminal equipment needs to perform intra-system switching or release subsequently.

24. The method of claim 23, wherein the handover request includes handover type information, and wherein the handover type information is used for indicating handover from the second communication system to the first communication system;

the first access network device sends a handover request response to the access and mobility management function, including:

and the first access network equipment sends the switching request response to the access and mobility management function according to the switching type information.

25. The method according to claim 23 or 24, further comprising:

the first access network device sends a fourth message to the access and mobility management function, where the fourth message is used to notify the access and mobility management function that the terminal device is switched, or the fourth message includes a registration request of the terminal device, where the registration request is used to request to register to the first communication system;

the first access network device receiving an indication from an access and mobility management function, comprising:

the first access network device receives a fifth message from the access and mobility management function, where the fifth message is used to indicate or request intra-system handover or release of the terminal device, and the fifth message includes a cause value, where the cause value is used to indicate that the CAG subscription of the terminal device is not supported.

26. The method of claim 20, 21 or 25, further comprising:

and the first access network equipment sends a sixth message to the access and mobility management function, wherein the sixth message is used for informing the access and mobility management function to wait for the subsequent triggering of the intra-system handover process by the first access network equipment, or informing the access and mobility management function to trigger the release process or waiting for the triggering of the release process by the first access network equipment.

27. The method of claim 26, further comprising:

the first access network device receiving a seventh message from the access and mobility management function;

if the sixth message is used to notify the access and mobility management function to wait for the subsequent first access network device to trigger a handover procedure in the system, the seventh message includes a registration accept, where the registration accept is used to indicate to accept the registration request of the terminal device;

28. The method according to any of claims 15 to 27, wherein the first access network device initiates an intra-system handover procedure or a release procedure, comprising:

and the first access network equipment signs a contract according to the CAG of the terminal equipment, if second access network equipment supporting the CAG sign is found, an intra-system switching process is initiated, and if not, a releasing process is initiated.

29. A communications apparatus, comprising at least one processor coupled with at least one memory:

the at least one processor configured to execute computer programs or instructions stored in the at least one memory to cause the apparatus to perform the method of any one of claims 1 to 14 or to cause the apparatus to perform the method of any one of claims 15 to 28.

30. A communication device comprising a processor and interface circuitry;

the interface circuit is used for interacting code instructions or data with the processor;

the processor is configured to perform the method of any one of claims 1 to 14 or the processor is configured to perform the method of any one of claims 15 to 28.

31. A computer-readable storage medium storing instructions that, when executed, cause the method of any of claims 1 to 14 to be implemented, or cause the method of any of claims 15 to 28 to be implemented.