Communication method, communication device, and communication system

Abstract

The present application provides a communication method, a communication device and a communication system. By using the GUTI allocation process, the first mobility management network element indicates multiple mobility management network elements to the terminal device, guiding the terminal device to access one of the multiple mobility management network elements, which realizes the access of the terminal device to the correct mobility management network element. Moreover, this solution does not depend on the core network to open the N14 interface or the base station to support the rerouting function, and there are no additional customization requirements for the terminal device, making it relatively easy to implement and deploy.

Description

Technical Field

[0001] This application relates to the field of wireless communication technologies, and in particular, to a communication method, a communication device, and a communication system. Background Art

[0002] When a terminal device registers with a mobility management network element of a core network, the base station needs to select a suitable mobility management network element and initiate a registration to the selected mobility management network element to request registering the terminal device with the mobility management network element.

[0003] However, when the base station selects a mobility management network element, it may select the wrong mobility management network element, and this mobility management network element cannot provide services to the terminal device. Therefore, a mechanism needs to be established so that the terminal device can be redirected to the correct mobility management network element to initiate registration. Summary of the Invention

[0004] This application provides a communication method, a communication device, and a communication system to redirect a terminal device to a correct mobility management network element.

[0005] In a first aspect, an embodiment of this application provides a communication method, which can be executed by a terminal device or a module (such as a chip) of the terminal device. The method includes: sending a registration request message, where the registration request message includes identification information of the terminal device, and the registration request message is used to request registration to a network; receiving a first globally unique temporary identity (GUTI) from the first mobility management network element, where the first GUTI includes mobility management network element set information, the mobility management network element indicated by the mobility management network element set information belongs to a private network core network and the first mobility management network element belongs to a macro network core network, or the mobility management network element indicated by the mobility management network element set information and the first mobility management network element belong to different private network core networks, or the mobility management network element indicated by the mobility management network element set information and the first mobility management network element belong to different macro network core networks; receiving a deregistration message from the first mobility management network element, where the deregistration message includes indication information, the deregistration message is used to trigger the terminal device to deregister, and the indication information is used to indicate initiating re-registration; according to the indication information, sending a re-registration request message, where the re-registration request message includes the first GUTI, and the first GUTI is used to select a mobility management network element that provides services to the terminal device.

[0006] In the above solution, by using the GUTI allocation process, the first mobility management network element instructs the terminal device to multiple mobility management network elements, guiding the terminal device to access one of the multiple mobility management network elements, achieving the access of the terminal device to the correct mobility management network element. Moreover, this solution does not rely on the core network to open the N14 interface or the base station to support the rerouting function, and there is no additional customization requirement for the terminal device, making it relatively easy to implement and deploy.

[0007] In a possible implementation method, the receiving the first GUTI from the first mobility management network element includes: receiving a registration acceptance message from the first mobility management network element, where the registration acceptance message includes the first GUTI.

[0008] In a possible implementation method, the receiving the first GUTI from the first mobility management network element includes:

[0009] receiving a reallocation command from the first mobility management network element, where the reallocation command includes the first GUTI.

[0010] In a possible implementation method, the registration request message is an initial registration request message, a mobility registration request message, an initial attachment request message, or a mobility attachment request message.

[0011] In a possible implementation method, the registration request message includes the identification information of the terminal device, including: the registration request message includes a second GUTI, and the second GUTI indicates the identification information of the terminal device.

[0012] In a second aspect, an embodiment of the present application provides a communication method, which can be executed by a first mobility management network element or a module (such as a chip) of the first mobility management network element. The method includes: receiving a registration request message from a terminal device, where the registration request message includes the identification information of the terminal device and is used to request registration to the network; sending a first GUTI to the terminal device, where the first GUTI includes mobility management network element set information, and the mobility management network elements indicated by the mobility management network element set information belong to a private network core network and the first mobility management network element belongs to a macro network core network, or the mobility management network elements indicated by the mobility management network element set information belong to different private network core networks from the first mobility management network element, or the mobility management network elements indicated by the mobility management network element set information belong to different macro network core networks from the first mobility management network element; the first mobility management network element sends a deregistration message to the terminal device, where the deregistration message includes indication information and is used to trigger the terminal device to deregister, and the indication information is used to indicate initiating re-registration.

[0013] In the above solution, by using the GUTI allocation process, the first mobility management network element indicates multiple mobility management network elements to the terminal device, guiding the terminal device to access one of the multiple mobility management network elements, achieving the access of the terminal device to the correct mobility management network element. Moreover, this solution does not rely on the core network to open the N14 interface or the base station to support the rerouting function, and there is no additional customization requirement for the terminal device, making it relatively easy to implement and deploy.

[0014] In one possible implementation method, sending the first GUTI to the terminal device includes: sending a registration acceptance message to the terminal device, where the registration acceptance message includes the first GUTI.

[0015] In one possible implementation method, sending the first GUTI to the terminal device includes: sending a reallocation command to the terminal device, where the reallocation command includes the first GUTI.

[0016] In one possible implementation method, the registration request message is an initial registration request message, a mobility registration request message, an initial attachment request message, or a mobility attachment request message.

[0017] In one possible implementation method, the registration request message includes the identification information of the terminal device, including: the registration request message includes a second GUTI, and the second GUTI indicates the identification information of the terminal device.

[0018] In one possible implementation method, the first GUTI is used to select a mobility management network element that provides services for the terminal device.

[0019] In a third aspect, an embodiment of the present application provides a communication method, which can be executed by a first mobility management network element or a module (such as a chip) of the first mobility management network element. The method includes: sending a first redirection request message to a second mobility management network element, where the first redirection request message includes the identification information of the terminal device, and the first redirection request is used to request redirecting the terminal device to the second mobility management network element; receiving a redirection response message from the second mobility management network element, where the redirection response message indicates that the redirection fails; sending a second redirection request message to a third mobility management network element, where the second redirection request message includes the identification information of the terminal device, and the second redirection request is used to request redirecting the terminal device to the third mobility management network element; where the second mobility management network element and the third mobility management network element are mutually primary and standby mobility management network elements.

[0020] In the above solution, when the network after redirection is a primary / backup network, if the roles of the primary mobility management network element and the backup mobility management network element change, the first mobility management network element can also accurately redirect the terminal device to the correct mobility management network element.

[0021] In a possible implementation method, the redirection message includes indication information for indicating that the second mobility management network element is a backup mobility management network element.

[0022] In a possible implementation method, sending the first redirection request message to the second mobility management network element includes: sending the first redirection request message to the second mobility management network element according to configuration information, where the configuration information indicates that the priority of the second mobility management network element is higher than the priority of the third mobility management network element, or indicates that the second mobility management network element is the primary mobility management network element and the third mobility management network element is the backup mobility management network element.

[0023] In the methods provided in the first aspect and the second aspect, in a possible implementation method, the method further includes: determining that the terminal device is served by the mobility management network element indicated by the mobility management network element set information according to any one or more of the following information: the identifier of the tracking area where the terminal device is located, the international mobile subscriber identity (IMSI) number segment corresponding to the terminal device, the subscribed slice of the terminal device, the usage category of the terminal device, or the cell accessed by the terminal device.

[0024] In a fourth aspect, an embodiment of the present application provides a communication device, which may be a terminal device or a module (such as a chip) of the terminal device. The device has the function of implementing any implementation method in the first aspect above. This function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions.

[0025] In a fifth aspect, an embodiment of the present application provides a communication device, which may be a first mobility management network element or a module (such as a chip) of the first mobility management network element. The device has the function of implementing any implementation method in the second aspect or the third aspect above. This function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions.

[0026] In a sixth aspect, an embodiment of the present application provides a communication device, including units or means for performing each step of any implementation method in the first aspect to the third aspect above.

[0027] In a seventh aspect, an embodiment of the present application provides a communication device, including a processor and an interface circuit. The processor is configured to communicate with other devices through the interface circuit and execute any implementation method in the above first aspect to third aspect. The processor includes one or more.

[0028] In an eighth aspect, an embodiment of the present application provides a communication device, including a processor. The processor is configured to call a program to execute any implementation method in the above first aspect to third aspect. And the processor may be one or more.

[0029] Optionally, the communication device may further include a memory, which is coupled to the processor. The memory may be located inside the device or outside the device.

[0030] In a ninth aspect, an embodiment of the present application provides a communication device, including a processor; when the device runs, the processor executes computer instructions to enable the device to execute any implementation method in the above first aspect to third aspect.

[0031] Optionally, the communication device may further include a memory, which is used to store the computer instructions.

[0032] In an eleventh aspect, an embodiment of the present application further provides a computer program product, which includes a computer program or instructions. When the computer program or instructions are run by a communication device, any implementation method in the above first aspect to third aspect is executed.

[0033] In a twelfth aspect, an embodiment of the present application further provides a chip system, including: a processor configured to execute any implementation method in the above first aspect to third aspect.

[0034] In a thirteenth aspect, an embodiment of the present application further provides a chip system, including: a processor configured to execute any implementation method in the above first aspect to third aspect.

[0035] In a thirteenth aspect, an embodiment of the present application further provides a communication system, including: an access network device, configured to receive a registration request message from a terminal device and send the registration request message to a first mobility management network element, where the registration request message includes identification information of the terminal device, and the registration request message is used to request registration to the network; receive a first GUTI from the first mobility management network element and send the first GUTI to the terminal device, where the first GUTI includes mobility management network element set information, the mobility management network elements indicated by the mobility management network element set information belong to a private network core network and the first mobility management network element belongs to a macro network core network, or the mobility management network elements indicated by the mobility management network element set information and the first mobility management network element belong to different private network core networks, or the mobility management network elements indicated by the mobility management network element set information and the first mobility management network element belong to different macro network core networks; and receive a deregistration message from the first mobility management network element and send the deregistration message to the terminal device, where the deregistration message includes indication information, the deregistration message is used to trigger the terminal device to deregister, and the indication information is used to indicate initiating re-registration; the first mobility management network element is configured to receive the registration request message from the terminal device through the access network device, and send the first GUTI and the deregistration message to the terminal device through the access network device.

[0036] In a fourteenth aspect, an embodiment of the present application further provides a communication system, including: a first mobility management network element, configured to send a first redirection request message to a second mobility management network element, where the first redirection request message includes identification information of a terminal device, and the first redirection request is used to request redirecting the terminal device to the second mobility management network element; receive a redirection response message from the second mobility management network element, where the redirection response message indicates that redirection fails; and send a second redirection request message to a third mobility management network element, where the second redirection request message includes the identification information of the terminal device, and the second redirection request is used to request redirecting the terminal device to the third mobility management network element; where the second mobility management network element and the third mobility management network element are primary and backup mobility management network elements to each other; the second mobility management network element is configured to receive the first redirection request message; and send the redirection response message; the third mobility management network element is configured to receive the second redirection request message. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1(a) is a schematic diagram of a communication system provided by an embodiment of the present application;

[0038] FIG. 1(b) is a schematic diagram of a communication system provided by an embodiment of the present application;

[0039] Figure 2(a) is a schematic diagram of the 4G EPC architecture;

[0040] Figure 2(b) is a schematic diagram of the 5G NR architecture;

[0041] Figure 3 It is an example of a network construction plan for establishing an independent campus base station for an enterprise park;

[0042] Figure 4(a) is an example of a network construction plan for sharing base stations between the public network and the campus;

[0043] Figure 4(b) is an example of a network construction plan for deploying two sets of public network core networks and sharing base stations;

[0044] Figure 5 It is an example of a network construction plan for deploying two sets of private network core networks in the same campus and sharing base stations;

[0045] Figure 6 It is a schematic flowchart of a communication method provided by an embodiment of the present application;

[0046] Figure 7 It is a schematic flowchart of a communication method provided by an embodiment of the present application;

[0047] Figure 8 It is a schematic flowchart of a communication method provided by an embodiment of the present application;

[0048] Figure 9 It is a schematic flowchart of a communication method provided by an embodiment of the present application;

[0049] Figure 10 It is a schematic diagram of the interface between mobility management network elements;

[0050] Figure 11 It is a schematic diagram of a communication device provided by an embodiment of the present application;

[0051] Figure 12 It is a schematic diagram of a communication device provided by an embodiment of the present application. Detailed implementation manners

[0052] The present application provides a communication system. Referring to Figure 1(a), the system includes an access network device and a first mobility management network element. The system shown in Figure 1(a) can be used in the network architecture shown in Figure 2(a) or Figure 2(b). Of course, it can also be used in future network architectures, such as the sixth generation (6G) network architecture, etc. The present application does not make any limitations.

[0053] In one implementation method, the first mobility management network element and the access network device in FIG. 1(a) are the mobility management entity (MME) in FIG. 2(a) and the access network device in the evolved universal terrestrial radio access network (E-UTRAN), respectively.

[0054] In another implementation method, the first mobility management network element and the access network device in FIG. 1(a) are the access and mobility management function (AMF) network element in FIG. 2(b) and the access network device in the radio access network (RAN), respectively.

[0055] In yet another implementation method, the access network device in FIG. 1(a) is a device with the function of an access network device in future communications such as 6G communications, and the first mobility management network element is a network element with the function of an AMF network element / MME in future communications such as 6G communications.

[0056] The access network device is configured to receive a registration request message from a terminal device and send the registration request message to the first mobility management network element. The registration request message includes identification information of the terminal device and is used to request registration to the network. The access network device is further configured to receive a first GUTI from the first mobility management network element and send the first GUTI to the terminal device. The first GUTI includes mobility management network element set information, and the mobility management network element indicated by the mobility management network element set information belongs to a private network core network and the first mobility management network element belongs to a macro network core network, or the mobility management network element indicated by the mobility management network element set information and the first mobility management network element belong to different private network core networks, or the mobility management network element indicated by the mobility management network element set information and the first mobility management network element belong to different macro network core networks. The access network device is further configured to receive a deregistration message from the first mobility management network element and send the deregistration message to the terminal device. The deregistration message includes indication information and is used to trigger the terminal device to deregister, and the indication information is used to indicate initiating re-registration. The first mobility management network element is configured to receive the registration request message from the terminal device through the access network device, and send the first GUTI and the deregistration message to the terminal device through the access network device.

[0057] A possible implementation method, the first mobility management entity is used to send a first GUTI to the access network device, specifically including: being used to send a registration acceptance message to the access network device, and the first GUTI is included in the registration acceptance message.

[0058] A possible implementation method, the first mobility management entity is used to send a first GUTI to the access network device, specifically including: being used to send a reallocation command to the access network device, and the first GUTI is included in the reallocation command.

[0059] A possible implementation method, the first mobility management entity is further used to determine, according to any one or more of the following information, that the terminal device is served by the mobility management entity indicated by the mobility management entity set information: the identifier of the tracking area where the terminal device is located, the IMSI number segment corresponding to the terminal device, the subscribed slice of the terminal device, the usage category of the terminal device, or the cell accessed by the terminal device.

[0060] The interaction between each network element in the system and the specific execution can refer to the method embodiments below and will not be elaborated here.

[0061] This application provides a communication system. Referring to FIG. 1(b), the system includes a first mobility management entity, a second mobility management entity, and a third mobility management entity.

[0062] The system shown in FIG. 1(b) can be used in the network architecture shown in FIG. 2(a) or FIG. 2(b). Of course, it can also be used in future network architectures, such as 6G network architectures, etc., and this application does not make any limitations.

[0063] In an implementation method, the first mobility management entity, the second mobility management entity, and the third mobility management entity in FIG. 1(b) are respectively different MMEs in FIG. 2(a).

[0064] In another implementation method, the first mobility management entity, the second mobility management entity, and the third mobility management entity in FIG. 1(b) are respectively different AMF entities in FIG. 2(b).

[0065] In another implementation method, the first mobility management entity, the second mobility management entity, and the third mobility management entity in FIG. 1(b) are entities with the functions of AMF entities / MMEs in future communications such as 6G communications.

[0066] The first mobility management network element is used to send a first redirection request message to the second mobility management network element. The first redirection request message includes the identification information of the terminal device. The first redirection request is used to request redirecting the terminal device to the second mobility management network element; receive a redirection response message from the second mobility management network element, where the redirection response message indicates that the redirection fails; and send a second redirection request message to the third mobility management network element. The second redirection request message includes the identification information of the terminal device. The second redirection request is used to request redirecting the terminal device to the third mobility management network element; where the second mobility management network element and the third mobility management network element are primary and standby mobility management network elements for each other. The second mobility management network element is used to receive the first redirection request message; and send the redirection response message; The third mobility management network element is used to receive the second redirection request message.

[0067] In a possible implementation method, the first mobility management network element is further used to determine, according to any one or more of the following information, that the terminal device is served by the second mobility management network element or the third mobility management network element: the identification of the tracking area where the terminal device is located, the IMSI number segment corresponding to the terminal device, the subscribed slice of the terminal device, the usage category of the terminal device, or the cell accessed by the terminal device.

[0068] In a possible implementation method, the first mobility management network element is used to send a first redirection request message to the second mobility management network element, specifically including: being used to send the first redirection request message to the second mobility management network element according to configuration information, where the configuration information indicates that the priority of the second mobility management network element is higher than the priority of the third mobility management network element, or indicates that the second mobility management network element is the primary mobility management network element and the third mobility management network element is the standby mobility management network element.

[0069] The interaction between each network element in the system and the specific execution can refer to the method embodiments below and will not be elaborated here.

[0070] Figure 2(a) is a schematic diagram of the architecture of the 4th generation (4G) evolved packet core (EPC) network. The functions of the main nodes in this architecture are described as follows:

[0071] E-UTRAN: It is the radio access network of 4G. The access network devices in E-UTRAN include, for example, 4G base stations.

[0072] MME: It is mainly responsible for access authentication and mobility management.

[0073] Serving Gateway (SGW): It is mainly responsible for session management, charging in the visited area in the roaming scenario, and policy enforcement.

[0074] Packet Data Network Gateway (PGW): It is mainly responsible for session management, policy, and charging enforcement.

[0075] Home Subscriber Server (HSS): It is mainly responsible for storing user subscription data information.

[0076] Policy and Charging Rules Function (PCRF) network element: It generates control policies based on the request information of the Application Function (AF) network element, operator policies, user subscription information, etc., controls network behavior, and issues control policies to the control plane network element for policy enforcement.

[0077] Data Network (DN) is a network outside the operator's network. The operator's network can access multiple DNs. Multiple services can be deployed on the DN, providing services such as data and / or voice for terminal devices. For example, the DN is the private network of a smart factory. The sensors installed in the workshop of the smart factory can be terminal devices. A control server for the sensors is deployed in the DN, and the control server can provide services for the sensors. The sensors can communicate with the control server, obtain instructions from the control server, and transmit the collected sensor data to the control server according to the instructions. Another example is that the DN is the internal office network of a company. The mobile phones or computers of the company's employees can be terminal devices, and the mobile phones or computers of the employees can access information, data resources, etc. on the company's internal office network.

[0078] The terminal device can be a user equipment (UE), a mobile station, a mobile terminal device, etc. The terminal device can be widely applied to various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IOT), virtual reality, augmented reality, industrial control, autonomous driving, remote medical treatment, smart grid, smart furniture, smart office, smart wearables, smart transportation, smart city, etc. The terminal device can be a mobile phone, a tablet computer, a computer with wireless transceiver function, a wearable device, a vehicle, an urban air vehicle (such as an unmanned aircraft, a helicopter, etc.), a ship, a robot, a robotic arm, a smart home device, etc. In Figure 2(a), the terminal device is taken as an example of UE for illustration.

[0079] To address the challenges of wireless broadband technology and maintain the leading edge of the 3rd generation partnership project (3GPP) network, the 3GPP standards group has developed the architecture of the next generation mobile communication network system (Next Generation System), known as the 5th generation (5G) network architecture. This architecture not only supports the access of wireless access technologies defined by the 3GPP standards group (such as long term evolution (LTE) access technology, 5G RAN access technology, etc.) to the 5G core network (CN), but also supports the access to the core network using non-3GPP access technologies through the non-3GPP interworking function (N3IWF) or the next generation packet data gateway (ngPDG).

[0080] Figure 2(b) is a schematic diagram of the 5G New Radio (NR) architecture. The 5G architecture shown in Figure 2(a) may include access network devices and core network devices. The terminal device accesses the data network (DN) through the access network device and the core network device. Among them, the core network device includes, but is not limited to, some or all of the following network elements: Authentication Server Function (AUSF) network element (not shown in the figure), Unified Data Management (UDM) network element, Unified Data Repository (UDR) network element, Network Repository Function (NRF) network element (not shown in the figure), Network Exposure Function (NEF) network element (not shown in the figure), AF network element, Policy Control Function (PCF) network element, Access and Mobility Management Function (AMF) network element, Session Management Function (SMF) network element, and User Plane Function (UPF) network element.

[0081] The access network device can be a radio access network device (RAN device) or a wired access network device. Among them, the radio access network device includes a 3GPP access network device, a non-trusted non-3GPP access network device, and a trusted non-3GPP access network device. The 3GPP access network device includes but is not limited to: the evolved NodeB (eNodeB) in LTE, the next generation NodeB (gNB) in the 5G mobile communication system, the base station in the future mobile communication system, or a module or unit that completes part of the base station functions, such as the central unit (CU), the distributed unit (DU), etc. The non-trusted non-3GPP access network device includes but is not limited to: the non-trusted non-3GPP access gateway or N3IWF device, the non-trusted wireless local area network (WLAN) access point (AP), switches, routers. The trusted non-3GPP access network device includes but is not limited to: the trusted non-3GPP access gateway, the trusted WLAN AP, switches, routers. The wired access network device includes but is not limited to: the wireline access gateway, the fixed telephone network device, switches, routers. For ease of description, this application uses the base station as an example of the access network device for illustration, and all subsequent base stations can be replaced with the access network device.

[0082] The access network device and the terminal device can be in a fixed position or movable. The access network device and the terminal device can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on the water surface; they can also be deployed on airplanes, balloons, and artificial satellites in the air. The embodiments of this application do not limit the application scenarios of the access network device and the terminal device.

[0083] The AMF network element includes functions such as performing mobility management, or access authentication / authorization, etc. In addition, it is also responsible for transmitting user policies between the terminal device and the PCF network element.

[0084] The SMF network element includes functions such as performing session management, executing the control policies issued by the PCF network element, selecting the UPF network element, or allocating the Internet Protocol (IP) address of the terminal device, etc.

[0085] The UPF network element includes functions such as completing user plane data forwarding, session / flow-level billing statistics, or bandwidth limitation, etc.

[0086] The UDM network element includes functions such as performing management of subscription data, or user access authorization, etc.

[0087] The UDR includes access functions for types of data such as execution subscription data, policy data, or application data.

[0088] The NEF network element is used to support the opening of capabilities and events.

[0089] The AF network element transmits the requirements from the application side to the network side. For example, QoS requirements or user status event subscriptions, etc. The AF can be a third-party functional entity or an application service deployed by the operator, such as the IP Multimedia Subsystem (IMS) voice call service. Among them, the AF network element includes the AF network element within the core network (i.e., the operator's AF network element) and the third-party AF network element (such as an enterprise's application server).

[0090] The PCF network element includes policy control functions such as being responsible for charging, QoS bandwidth guarantee, and mobility management at the session and service flow levels, or terminal device policy decision-making. The PCF network element includes the access and mobility management policy control function (AM PCF) network element and the session management policy control function (SM PCF) network element. Among them, the AM PCF network element is used to formulate AM policies and user policies for the terminal device. The AM PCF network element can also be called the policy control network element that provides services for the terminal device (PCF for a UE). The SM PCF network element is used to formulate session management policies (SM policies) for sessions. The SM PCF network element can also be called the policy control network element that provides services for the protocol data unit (PDU) session ((PCF for a PDU session)).

[0091] The NRF network element can be used to provide a network element discovery function and provide network element information corresponding to the network element type based on the requests of other network elements. The NRF network element also provides network element management services, such as network element registration, update, deregistration, or network element status subscription and push, etc.

[0092] The AUSF network element is responsible for authenticating users to determine whether to allow users or devices to access the network.

[0093] For the introduction of the DN in Figure 2(b), please refer to the introduction of the DN in the architecture of Figure 2(a), which will not be elaborated here.

[0094] For the introduction of the terminal device in FIG2(b), reference can be made to the introduction of the terminal device in the architecture of FIG2(a), which will not be repeated. In FIG2(b), the terminal device is UE as an example for illustration.

[0095] In Figure 2(b), N1, N2, N3, N4, N5, N6, etc. are interface serial numbers, and their meanings are as follows:

[0096] 1) N1: The interface between the AMF network element and the terminal device, which can be used to transmit non-access stratum (NAS) signaling (such as QoS rules from the AMF network element) to the terminal device.

[0097] 2) N2: The interface between the AMF network element and the access network equipment, which can be used to transmit wireless bearer control information from the core network side to the access network equipment.

[0098] 3) N3: The interface between the access network equipment and the UPF network element, mainly used to transmit uplink and downlink user plane data between the access network equipment and the UPF network element.

[0099] 4) N4: The interface between the SMF network element and the UPF network element can be used to transmit information between the control plane and the user plane, including controlling the issuance of forwarding rules, QoS rules, traffic statistics rules, etc. for the user plane and reporting of information on the user plane.

[0100] 5) N5: The interface between AF network element and PCF network element, which can be used to send application service requests and report network events.

[0101] 6) N6: The interface between UPF network element and DN, used to transmit the uplink and downlink user data flows between UPF network element and DN.

[0102] 7) N7: The interface between PCF network element and SMF network element, which can be used to send PDU session granularity and service data flow granularity control strategy.

[0103] 8) N8: The interface between the AMF network element and the UDM network element, which can be used by the AMF network element to obtain access and mobility management-related contract data and authentication data from the UDM network element, and the AMF network element to register terminal device mobility management-related information with the UDM network element.

[0104] 9) N9: User plane interface between UPF network elements, used to transmit uplink and downlink user data flows between UPF network elements.

[0105] 10) N10: The interface between SMF network element and UDM network element, which can be used by SMF network element to obtain session management related contract data from UDM network element, and SMF network element to register terminal device session related information with UDM network element.

[0106] 11) N11: The interface between SMF network element and AMF network element, which can be used to transmit PDU session tunnel information between access network equipment and UPF, transmit control messages sent to terminal equipment, transmit wireless resource control information sent to access network equipment, etc.

[0107] 12) N15: The interface between the PCF network element and the AMF network element, which can be used to issue terminal device policies and access control related policies.

[0108] 13) N35: The interface between the UDM network element and the UDR network element, which can be used by the UDM network element to obtain user contract data information from the UDR network element.

[0109] 14) N36: The interface between the PCF network element and the UDR network element, which can be used by the PCF network element to obtain policy-related contract data and application data-related information from the UDR network element.

[0110] It is understandable that the above network element or function can be a network element in a hardware device, a software function running on dedicated hardware, or a virtualized function instantiated on a platform (e.g., a cloud platform). Optionally, the above network element or function can be implemented by one device, or by multiple devices, or a functional module in one device, which is not specifically limited in the embodiments of the present application.

[0111] As we all know, 5G will enable the digital transformation of thousands of industries. The newly released 5G R16 standard is to better promote the expansion of 5G to vertical industries. There are two main ways for 5G to expand to vertical industries in the form of private networks.

[0112] One is that operators share 5G network resources with vertical industries. For example, they deploy 5G private networks for vertical industries by sharing base stations and core network control planes, or use network slicing technology to cut out multiple virtual private networks for vertical industries end-to-end on a 5G public network.

[0113] The other is that vertical industries use lightweight equipment to independently build the entire 5G network, which can be isolated from the operator's 5G public network. This means that the equipment information, control plane signaling traffic, user plane data traffic, etc. in the factory or park will not leave the park and will not enter the operator's 5G public network. This highly customized network can maximize the performance of the 5G network, achieving coverage without dead ends, data not leaving the park, uninterrupted production, optimized uplink and downlink bandwidth, ultra-low latency, and ultra-high reliability.

[0114] When building 5G core network elements independently in vertical industries, there are two ways to build a base station network:

[0115] Method 1: Build an independent campus base station in the park.

[0116] Figure 3 An example of a network construction plan for building an independent campus base station for an enterprise park. A new campus base station is built in the enterprise park. For example, a new independent in-building distribution base station is built in the park production environment to provide services specifically for production equipment. Large network terminal devices cannot access this independent base station. Large network terminal devices are provided with services by the original large network base stations, or there are no large network terminal devices in this area.

[0117] Method 2: Share the base stations of the large network in the park.

[0118] Figure 4(a) is an example of a network construction plan for sharing base stations between the large network and the park. Reuse the original large network base stations in the enterprise park to provide private network services. The large network and the private network share the base stations. This scenario of deploying a private network from the operator to the enterprise park is relatively common and is easier to build. The independent private network core network provides the ability to keep data and signaling within the park. The shared base stations are connected to the private network core network independently built in the enterprise park. Under this network construction plan, the same base station provides both large network services and private network services. Large network terminal devices are connected to the large network core network, and private network terminal devices are connected to the enterprise's private network core network. The network side needs to provide a private network selection plan.

[0119] When building an enterprise private network, there are similar requirements for those including 4G services.

[0120] In the embodiments of this application, the large network refers to a macro network or a public network, and the private network refers to a private network or a campus network.

[0121] 3GPP 23.502 describes the AMF reallocation process, which can theoretically be applied to the scenario where the large network and the private network share base stations and the park has an independent private network core network. For example, if the default AMF (default AMF) set on the shared base station is the AMF of the large network core network, then after the shared base station receives a registration request from a terminal device, it forwards the registration request to the AMF of the large network core network. When the AMF of the large network core network discovers that the registration request carries a campus slice, the AMF of the large network core network has two ways to redirect this terminal device to the private network core network:

[0122] Method A: The AMF of the large network core network acts as the initial AMF (initial AMF), and through the N14 interface between the initial AMF and the campus AMF, takes the campus AMF as the target AMF (target AMF) and redirects the terminal device to the target AMF.

[0123] Method B: The AMF of the large core network acts as the initial AMF and returns a reroute NAS message to the shared base station, notifying the shared base station that the redirected AMF is the campus AMF. The shared base station sends a registration request to the campus AMF.

[0124] The above method A implements private network selection through redirection between two sets of AMF, but has the following defects:

[0125] First, the two core networks need to have an N14 interface connected. Since the enterprise park has built a whole set of enterprise private networks, it is actually unwilling to be associated with the operator's large network core network. This solution also requires the N14 interface to be connected. Enterprise customers will have concerns, thinking that their independent core networks are not completely isolated, data does not leave the park, and does not meet the high security requirements of the enterprise; the operator's large network will also have concerns, considering that the enterprise private network is deployed in the enterprise computer room, not the operator's core network computer room, there is a possibility that malicious attackers want to attack the operator's large network through the enterprise edge, and the operator's large network will also consider the security risks. Therefore, some operators / enterprises do not agree to build an N14 interface between the two networks.

[0126] Second, if the campus private network is a primary-backup network, the core network of the large network cannot identify which is the primary mobility management network element and which is the backup mobility management network element in the campus private network, and therefore cannot accurately redirect to the appropriate mobility management network element.

[0127] The above method B realizes private network selection by redirecting shared base stations, but has the following defects:

[0128] First, base stations need to be upgraded to support reroute NAS messages. For example, if there are still existing 4G users in the enterprise park, this involves 4G base stations and 5G base stations. However, some manufacturers' base stations do not support the reroute function and need to be developed, which is difficult for operators to promote.

[0129] Second, the registration of the target AMF of the terminal device in the private network will fail because: after the initial AMF of the public network receives the registration request message from the terminal device, it establishes and activates a new security context with the terminal device, and the terminal device can only receive and process messages protected by this new security context. If the initial AMF determines that it cannot provide services to the terminal device, it selects the target AMF of the campus and performs NAS reroute through the shared base station, sending the registration request message to the target AMF through the shared base station. The target AMF sends a NAS message to the terminal device. Since the target AMF cannot obtain the new security context established between the terminal device and the initial AMF, it cannot protect the downlink NAS message with the new security context. As a result, the terminal device will reject the NAS message sent by the target AMF, leading to registration failure and inability to access the network.

[0130] The above introduces the redirection method and existing problems in the scenario of sharing base stations between the public network and the private network. In addition, for other scenarios, such as scenarios where different public networks are isolated from each other, or scenarios where different private networks are isolated from each other, there may be similar methods and existing problems.

[0131] Figure 4(b) shows an example of a network construction plan for deploying two sets of public network core networks and sharing base stations. Two public networks share the same base station, which can be connected to the public network core network 1 or the public network core network 2. For example, in the user migration scenario, it is necessary to redirect the terminal device registered to the public network core network 1 to the public network core network 2. Another example is that the public network core network 1 is a mass market network facing customers (to customer), and the public network core network 2 is an Internet of Things network facing enterprises (to business). Then, when the terminal device accesses the core network, if it is mis-registered to the public network core network 1, it needs to be redirected to the public network core network 2, or if it is mis-registered to the public network core network 2, it needs to be redirected to the public network core network 1. How to redirect the terminal device to the public network core network 1 or the public network core network 2 also has the above two methods (i.e., redirection through the N14 interface or base station rerouting), and there are similar defects.

[0132] Figure 5An example of a network construction solution for deploying two private network core networks in the same park and sharing base stations. In this example, office terminal devices in the same park use private network core network 1, and production terminal devices use private network core network 2, but share base stations, that is, private network core network 1 and private network core network 2 share the same base station. Or the office terminal devices and production terminal devices are terminal devices in different parks of the same enterprise, and business isolation is achieved. At this time, private network core network 1 can be used as the default core network. For example, if the registration request message sent by the production terminal device is sent to private network core network 1, then how to redirect this terminal device to private network core network 2 also has the above two methods (i.e., redirect through the N14 interface or reroute through the base station), and there are similar defects.

[0133] To solve the above problems, the present application provides corresponding solutions.

[0134] Figure 6 A schematic diagram of the structures of the 5G globally unique temporary identity (5G-GUTI) and the 4G-GUTI. The 5G-GUTI is a temporary identity identifier assigned by the AMF network element to the terminal device during terminal device registration. <5G-GUTI> := <guami><5G-TMSI>, wherein, <guami> :＝ <mcc> <mnc><AMF Region ID><AMF Set ID><AMF Pointer>. GUAMI is the abbreviation of globally unique AMF identifier.

[0135] The field names and meanings in 5G-GUTI are as follows:

[0136] Mobile Country Code (MCC) / Mobile Network Code (MNC) field: This field contains MCC and MNC.

[0137] AMF Region ID field: This field indicates the AMF Region, and one or more AMF Sets can be included in an AMF Region.

[0138] AMF Set ID field: This field indicates an AMF Set. An AMF Set consists of two or more AMF network elements that can serve the same slice type.

[0139] AMF Pointer field: AMF Set ID + AMF Pointer can uniquely identify an AMF network element within an AMF Set.

[0140] 5G Temporary Mobile Subscriber Identity (5G-TMSI) field: This field indicates the temporary identity assigned by the AMF network element to the terminal device, which is used to identify the terminal device.

[0141] 4G-GUTI is the temporary identity assigned by the MME to the terminal device during the terminal device registration, <4G-GUTI>:= <gummei> <m-tmsi>, wherein, <gummei> :＝ <mcc> <mnc> <mmegi> <mmec>。GUMMEI is the abbreviation of globally unique MME identifier.

[0142] The 4G-GUTI is a temporary identity identifier assigned by the MME to the terminal device during registration. The field names and meanings in the 4G-GUTI are as follows:

[0143] MCC / MNC field: This field contains the MCC and MNC.

[0144] MME Group ID (MMEGI) field: This field indicates the MME Group. One or more MMEs can be included in an MME Group.

[0145] MME Code (MMEC) field: This field is used to uniquely identify an MME in the MME Group.

[0146] MME-temporary mobile subscriber identity (M-TMSI) field: This field indicates the temporary identity identifier assigned by the MME to the terminal device and is used to identify the terminal device.

[0147] It can be seen that the 5G-GUTI indicates the AMF through three sections. Among them, the AMF region and the AMF set are two-level geographical divisions. Each AMF Region consists of one or more AMF Sets, and an AMF Set is composed of some AMFs serving a given area and network slice. The AMF pointer represents a specific AMF. The 4G-GUTI indicates the MME through two sections. One is the MME group ID representing the MME pool, and the MME Code represents a specific MME.

[0148] The relationship between the 5G-GUTI and the 4G-GUTI is as follows:

[0149] 1), Both the 5G-GUTI and the 4G-GUTI contain MCC / MNC;

[0150] 2), There is a mapping relationship between the AMF Region ID, AMF Set ID, and AMF Pointer in the 5G-GUTI and the MMEGroup ID and MMECode in the 4G-GUTI;

[0151] Specifically, there is a mapping relationship between the AMF Region ID (8 bits in total) and the high 8 to 15 bits of the MME group ID. There is a mapping relationship between the AMF Set ID (10 bits in total) and the low 0 to 7 bits of the MME group ID and the high 6 to 7 bits of the MME Code. There is a mapping relationship between the AMF Pointer (6 bits in total) and the low 0 to 5 bits of the MME Code.

[0152] 3) The 5G-TMSI in the 5G-GUTI is similar to the M-TMSI in the 4G-GUTI.

[0153] Figure 7 It is a schematic flowchart of a communication method provided by an embodiment of the present application. This method is executed by a terminal device or a module of the terminal device (such as a chip), and a first mobility management network element or a module of the first mobility management network element (such as a chip). Hereinafter, an example in which the terminal device and the first mobility management network element execute this method will be used for illustration. Among them, in the 4G architecture, the first mobility management network element is the MME. In the 5G architecture, the first mobility management network element is the AMF network element.

[0154] This method includes the following steps:

[0155] Step 701a, the terminal device sends a registration request message to the base station. Correspondingly, the base station receives this registration request message.

[0156] This registration request message includes the identification information of the terminal device, and this registration request message is used to request registration to the network.

[0157] Specifically, for the 4G network, the terminal device sends this registration request message to the 4G base station, and this registration request may be an initial attachment request message or a mobility attachment request message. The terminal device identification information in this registration request message may be an international mobile subscriber identity (IMSI) or the M-TMSI carried in the second GUTI, that is, the registration request message includes the IMSI, or includes the second GUTI, and this second GUTI contains the M-TMSI.

[0158] For a 5G network, the terminal device sends the registration request message to the 5G base station. The registration request can be an initial registration request message or a mobility registration request message. The terminal device identification information in the registration request message can be a subscription permanent identifier (SUPI), a subscription concealed identifier (SUCI), or a 5G-TMSI carried in the second GUTI. That is, the registration request message includes the SUCI, or includes the SUPI, or includes the second GUTI, and the second GUTI contains the 5G-TMSI.

[0159] The 4G base station or 5G base station here refers to a shared base station. For example, it is the base station shared by the public network and the private network shown in Figure 4(a), or the base station shared by two or more public networks in Figure 4(b), or Figure 5 the base station shared by two or more private networks in

[0160] Step 701b, the base station sends a registration request message to the first mobility management network element. Correspondingly, the first mobility management network element receives the registration request message.

[0161] After receiving the registration request message, the 4G base station or 5G base station forwards the registration request message to the first mobility management network element. It should be noted that before sending the registration request message to the first mobility management network element, the 4G base station or 5G base station also needs to perform a selection operation of the mobility management network element and select the first mobility management network element.

[0162] Step 702, the first mobility management network element sends the first GUTI to the terminal device. Correspondingly, the terminal device receives the first GUTI.

[0163] Specifically, the first mobility management network element sends the first GUTI to the base station, and then the base station sends the first GUTI to the terminal device.

[0164] Exemplarily, the first GUTI is carried in a registration acceptance message, a reallocation command, or a GUTI reallocation command.

[0165] The first GUTI is allocated by the first mobility management network element. The first GUTI includes mobility management network element set information. The mobility management network elements indicated by the mobility management network element set information belong to the private network core network, and the first mobility management network element belongs to the macro network core network. Or, the mobility management network elements indicated by the mobility management network element set information and the first mobility management network element belong to different private network core networks. Or, the mobility management network elements indicated by the mobility management network element set information and the first mobility management network element belong to different macro network core networks. Among them, the mobility management network elements indicated by the mobility management network element set information may belong to the same private network core network or different private network core networks.

[0166] In a 5G network, the first GUTI may be a 5G-GUTI. The mobility management network element set information includes an AMF RegionID and an AMF Set ID, or includes an AMF Region ID, an AMF Set ID, and an AMF Pointer, or includes an AMF SetID, or includes an AMF Set ID and an AMF Pointer. In a 4G network, the first GUTI may be a 4G-GUTI. The mobility management network element set information includes an MME Group ID, or includes an MME Group ID and an MME Code.

[0167] Taking the example of Figure 4(a), in a 5G network, the first mobility management network element is an AMF network element within the macro network core network, and the mobility management network elements indicated by the mobility management network element set information are one or more AMF network elements within the private network core network. If the mobility management network element set information indicates multiple AMF network elements, the multiple AMF network elements may belong to the same private network core network or different private network core networks. Or, in a 4G network, the first mobility management network element is an MME within the macro network core network, and the mobility management network elements indicated by the mobility management network element set information are one or more MMEs within the private network core network. If the mobility management network element set information indicates multiple MMEs, the multiple MMEs may belong to the same private network core network or different private network core networks.

[0168] Taking the example of Fig. 4(b), in a 5G network, the first mobility management network element is the AMF network element within the core network 1 of the large network. The mobility management network element indicated by the mobility management network element set information is one or more AMF network elements within the core network 2 of the large network, or the mobility management network element indicated by the mobility management network element set information is an AMF network element within multiple core networks of the large network that is different from the core network 1 of the large network. For example, the mobility management network element set information indicates AMF network element 1, AMF network element 2, and AMF network element 3, and AMF network element 1 belongs to the core network 2 of the large network, and AMF network element 2 and AMF network element 3 belong to the core network 3 of the large network. Alternatively, in a 4G network, the first mobility management network element is the MME within the core network 1 of the large network. The mobility management network element indicated by the mobility management network element set information is one or more MMEs within the core network 2 of the large network, or the mobility management network element indicated by the mobility management network element set information is an MME within multiple core networks of the large network that is different from the core network 1 of the large network. For example, the mobility management network element set information indicates MME1, MME2, and MME3, and MME1 belongs to the core network 2 of the large network, and MME2 and MME3 belong to the core network 3 of the large network.

[0169] Taking Figure 5 the example of, in a 5G network, the first mobility management network element is the AMF network element within the private core network 1. The mobility management network element indicated by the mobility management network element set information is one or more AMF network elements within the private core network 2, or the mobility management network element indicated by the mobility management network element set information is an AMF network element within multiple private core networks that is different from the private core network 1. For example, the mobility management network element set information indicates AMF network element 1, AMF network element 2, and AMF network element 3, and AMF network element 1 belongs to the private core network 2, and AMF network element 2 and AMF network element 3 belong to the private core network 3. Alternatively, in a 4G network, the first mobility management network element is the MME within the private core network 1. The mobility management network element indicated by the mobility management network element set information is one or more MMEs within the private core network 2, or the mobility management network element indicated by the mobility management network element set information is an MME within multiple private core networks that is different from the private core network 1. For example, the mobility management network element set information indicates MME1, MME2, and MME3, and MME1 belongs to the private core network 2, and MME2 and MME3 belong to the private core network 3.

[0170] In an implementation method, step 702 is specifically: when the first mobility management network element determines that the terminal device is served by the mobility management network element indicated by the mobility management network element set information, it sends a first GUTI to the terminal device. Exemplarily, the first mobility management network element determines that the terminal device is served by the mobility management network element indicated by the mobility management network element set information based on any one or more of the following information:

[0171] 1) The identifier (tracking area identity, TAI) of the tracking area where the terminal device is located;

[0172] 2) The IMSI number segment corresponding to the terminal device;

[0173] 3) The subscribed slice of the terminal device;

[0174] 4) The usage type of the terminal device;

[0175] 5) The cell to which the terminal device is connected.

[0176] Exemplarily, the first mobility management entity determines that the terminal device is a campus terminal device based on the TAI where the terminal device is located and the IMSI number segment corresponding to the terminal device, and determines that the mobility management entity indicated by the mobility management entity set information provides services.

[0177] Exemplarily, the first mobility management entity determines that the terminal device is a campus terminal device based on the TAI where the terminal device is located and the subscribed slice of the terminal device, and determines that the mobility management entity indicated by the mobility management entity set information provides services.

[0178] Exemplarily, the first mobility management entity determines that the terminal device is a campus terminal device based on the cell to which the terminal device is connected and the IMSI number segment corresponding to the terminal device, and determines that the mobility management entity indicated by the mobility management entity set information provides services.

[0179] Exemplarily, the first mobility management entity determines that the terminal device is a campus terminal device based on the cell to which the terminal device is connected and the subscribed slice of the terminal device, and determines that the mobility management entity indicated by the mobility management entity set information provides services.

[0180] Step 703, the first mobility management entity sends a deregistration message to the terminal device. Correspondingly, the terminal device receives the deregistration message.

[0181] Specifically, the first mobility management entity sends a deregistration message to the base station, and then the base station sends the deregistration message to the terminal device.

[0182] The deregistration message is used to trigger the terminal device to deregister, that is, to trigger the terminal device to deregister from the first mobility management entity.

[0183] The deregistration message includes indication information, and the indication information is used to indicate the initiation of reregistration.

[0184] Step 704, the terminal device sends a reregistration request message according to the indication information.

[0185] The re-registration request message includes a first GUTI, where the first GUTI is used to select a mobility management network element that provides services for the terminal device.

[0186] On the one hand, the terminal device deregisters from the first mobility management network element according to the deregistration message. On the other hand, a re-registration request message is sent to the base station according to the indication information. Then, the base station selects a mobility management network element according to the mobility management network element set information in the first GUTI, for example, selects a second mobility management network element, and sends a re-registration request message to the second mobility management network element, thereby registering the terminal device to the second mobility management network element. The second mobility management network element is, for example, an AMF network element or MME in the private network core network shown in FIG4(a), or an AMF network element or MME in the large network core network 2 shown in FIG4(b), or Figure 5 The AMF network element or MME within the example private network core network 2.

[0187] The above solution utilizes the GUTI allocation process, and the first mobility management network element indicates multiple mobility management network elements to the terminal device, guiding the terminal device to access one of the multiple mobility management network elements, thereby connecting the terminal device to the correct mobility management network element. This solution does not rely on the core network to open the N14 interface or the base station to support the rerouting function, and there is no additional customization requirement for the terminal device, so it is relatively easy to implement and deploy.

[0188] Combine the following Figure 8 Given the above Figure 7 A specific example of an embodiment.

[0189] Figure 8 A flow chart of a communication method provided in an embodiment of the present application. This embodiment takes the example of FIG. 4( a) as an example, and both the large network core network and the private network core network are 5G networks.

[0190] The method comprises the following steps:

[0191] Step 800, pre-configure attribute information of campus users on the first AMF network element.

[0192] The park users refer to private network users, that is, not large network users.

[0193] The attribute information of the campus user includes at least one of the following information: the identifier of the tracking area where the terminal device is located, the IMSI number segment corresponding to the terminal device, the contract slice of the terminal device, the usage category of the terminal device, or the cell accessed by the terminal device.

[0194] Step 801: The terminal device sends an access network (AN) message to the base station. Correspondingly, the base station receives the AN message.

[0195] This base station is a shared base station for the public network and the private network.

[0196] This AN message includes AN parameters and a registration request message. The base station can read the AN parameters, but does not read the content of the registration request message.

[0197] The AN parameters include the requested network slicing selection assistance information (NSSAI), the selected public land mobile network (PLMN), and the radio resource control (RRC) establishment cause value. Optionally, it also includes 5G-GUTI.

[0198] The registration request message includes a registration type, which is an initial registration or a mobile registration. Also, the registration request message further includes SUCI, SUPI, or 5G-GUTI.

[0199] Step 802, the base station selects an AMF network element.

[0200] The base station executes the selection process of the AMF network element. If the 5G-GUTI is included in the AN message, the AMF network element can be selected according to the 5G-GUTI. If the 5G-GUTI is not included in the AN message, the AMF network element is selected according to the radio access technology (RAT) and the requested NSSAI. Or, if the 5G-GUTI is not included in the AN message, the default AMF network element can also be selected.

[0201] If the base station cannot select a suitable AMF network element, the registration request message can be forwarded to the default AMF network element configured in the base station, and the default AMF network element selects a suitable AMF network element.

[0202] The following takes the selected AMF network element being the first AMF network element in the core network of the public network as an example.

[0203] Step 803, the base station sends an N2 message (N2 Message) to the first AMF network element. Correspondingly, the first AMF network element receives the N2 message.

[0204] The N2 message includes N2 parameters and a registration request message. The registration request message comes from the AN message in step 802.

[0205] The N2 parameter includes at least one of the PLMN ID, the identifier of the cell where the terminal device is located (cell ID), the context request, or the reason for establishing the RRC. Among them, the context request is used to indicate that it is necessary to establish a terminal device context containing security information at the base station.

[0206] Step 804, the first AMF network element determines that the terminal device is a campus user according to the pre-configured attribute information of the campus user.

[0207] After determining that the terminal device is a campus user, the first AMF network element decides that it is necessary to guide the terminal device to reselect to the AMF network element of the private network core network subsequently.

[0208] Step 805, the first AMF network element performs the authentication process, NAS signaling encryption, and integrity protection process according to the definition of the standard 3GPP.

[0209] After step 805, the following steps 806 and steps 808 to 811 are executed, or the following steps 807a, 807b, and steps 808 to 811 are executed.

[0210] Step 806, the first AMF network element sends a registration accept message to the terminal device. Correspondingly, the terminal device receives the registration accept message.

[0211] The registration accept message includes a 5G-GUTI, and the 5G-GUTI includes AMF network element set information, and the AMF network element set information indicates one or more AMF network elements within the private network. The 5G-GUTI is Figure 7 A specific example of the first GUTI in the embodiment.

[0212] In one example, the AM Set ID in the 5G-GUTI indicates one or more AMF network elements within the private network, and the AMF Pointer indicates an AMF ID in the AM Set ID.

[0213] In another example, the AM Set ID in the 5G-GUTI indicates one or more AMF network elements within the private network, and the AMF ID indicated by the AMF Pointer does not belong to the AM Set ID.

[0214] Step 807a, the first AMF network element sends a registration accept message to the terminal device. Correspondingly, the terminal device receives the registration accept message.

[0215] Step 807b, the first AMF network element sends a GUTI reallocation command to the terminal device. Correspondingly, the terminal device receives the GUTI reallocation command.

[0216] The GUTI reallocation command includes a 5G-GUTI, which is the same as the 5G-GUTI described in step 806. Reference can be made to the foregoing description.

[0217] Step 808: The first AMF network element sends a deregistration message to the terminal device. Accordingly, the terminal device receives the deregistration message.

[0218] The deregistration message is used to instruct the terminal device to deregister, that is, to deregister from the first AMF network element. And the deregistration message includes indication information, which is used to instruct the terminal device to initiate reregistration.

[0219] Step 809: The terminal device sends an AN message to the base station. Accordingly, the base station receives the AN message.

[0220] The AN message includes AN parameters and a reregistration request message. The base station can read the AN parameters, but does not read the content of the reregistration request message.

[0221] The AN parameters include the requested NSSAI, the selected PLMN, the RRC establishment cause value, and the 5G-GUTI. The reregistration request message includes the 5G-GUTI. The 5G-GUTI is the 5G-GUTI issued in step 806 or step 807b.

[0222] Step 810: The base station selects an AMF network element.

[0223] The base station executes the selection process of the AMF network element. The base station selects an AMF network element within the private network according to the AMF Set ID + AMF Pointer of the 5G-GUTI.

[0224] In one example, if the AM Set ID in the 5G-GUTI indicates one or more AMF network elements within the private network, and the AMF Pointer indicates an AMF ID within the AM Set ID, the base station can select the AMF network element indicated by the AMF Pointer.

[0225] In another example, if the AM Set ID in the 5G-GUTI indicates one or more AMF network elements within the private network, and the AMF ID indicated by the AMF Pointer does not belong to the AM Set ID, the base station can select an AMF network element from the AMF network elements indicated by the AM Set ID.

[0226] Taking the selected AMF network element as the second AMF network element within the core network of the private network as an example, and the second AMF network element is the AMF network element indicated by the AMF Set ID in the 5G-GUTI.

[0227] Step 811: The base station sends an N2 message to the second AMF network element. Correspondingly, the second AMF network element receives the N2 message.

[0228] The N2 message includes N2 parameters and a re-registration request message. The re-registration request message comes from the AN message in step 809.

[0229] The N2 parameter includes at least one of the PLMN ID, the identifier of the cell where the terminal device is located, a context request, or a reason for establishing RRC. The context request is used to indicate that a terminal device context containing security information needs to be established in the base station.

[0230] After the second AMF network element receives the re-registration request message, it continues the subsequent registration process and completes the registration of the terminal device, so that the terminal device successfully registers to the second AMF network element, realizing redirection from the first AMF network element to the second AMF network element.

[0231] The above solution utilizes the GUTI allocation process. The first AMF network element indicates multiple AMF network elements to the terminal device, guiding the terminal device to access one of the multiple AMF network elements, thereby connecting the terminal device to the correct AMF network element. This solution does not rely on the core network to open the N14 interface or the base station to support the rerouting function. There are no additional customization requirements for the terminal device, and it is relatively easy to implement and deploy.

[0232] Figure 9 A flow chart of a communication method provided for an embodiment of the present application. The method is executed by a first mobility management network element or a module (such as a chip) of the first mobility management network element, a second mobility management network element or a module (such as a chip) of the second mobility management network element, and a third mobility management network element or a module (such as a chip) of the third mobility management network element. The following is an example of the first mobility management network element, the second mobility management network element and the third mobility management network element executing the method. Among them, in the 4G architecture, the first mobility management network element, the second mobility management network element and the third mobility management network element are all MMEs. In the 5G architecture, the first mobility management network element, the second mobility management network element and the third mobility management network element are all AMF network elements.

[0233] The second mobility management network element and the third mobility management network element are each other's primary and backup mobility management network elements. For example, the second mobility management network element is the primary mobility management network element and the third mobility management network element is the backup mobility management network element; or the second mobility management network element is the backup mobility management network element and the third mobility management network element is the primary mobility management network element.

[0234] The method comprises the following steps:

[0235] Step 901, the first mobility management entity sends a first redirection request message to the second mobility management entity. Correspondingly, the second mobility management entity receives the first redirection request message.

[0236] The first redirection request message includes the identification information of the terminal device, and the first redirection request is used to request to redirect the terminal device to the second mobility management entity.

[0237] Exemplarily, configuration information is pre-stored in the first mobility management entity, and the configuration information indicates that the priority of the second mobility management entity is higher than that of the third mobility management entity, or indicates that the second mobility management entity is the primary mobility management entity and the third mobility management entity is the standby mobility management entity. Therefore, step 901 is specifically: the first mobility management entity sends a first redirection request message to the second mobility management entity according to the configuration information. That is, the first mobility management entity considers the second mobility management entity as the primary mobility management entity according to the configuration information, and therefore sends a first redirection request message to the second mobility management entity.

[0238] The configuration information may be sent to the first mobility management entity by the second mobility management entity or the third mobility management entity, or may be generated by the first mobility management entity. For example, the first mobility management entity queries the identification information of the subscribed slice of the terminal device from the UDM entity, and then the first mobility management entity queries the AMF Set corresponding to the identification information of the subscribed slice from the network slice selection function (NSSF) entity. The AMF Set includes the second mobility management entity and the third mobility management entity. Then the first mobility management entity queries the IP addresses of the AMF entities in the AMF Set from the NRF entity. Optionally, it also queries the priority of the IP addresses of the AMF entities in the AMF Set from the NRF entity, or the first mobility management entity configures the priority of the IP addresses of the AMF entities in the AMF Set.

[0239] In one implementation method, step 901 is specifically: if the first mobility management entity determines that the terminal device is served by the second mobility management entity or the third mobility management entity, the first mobility management entity sends a first redirection request message to the second mobility management entity, or the first mobility management entity sends a first redirection request message to the second mobility management entity according to the configuration information. Exemplarily, the first mobility management entity determines that the terminal device is served by the second mobility management entity or the third mobility management entity according to any one or more of the following information:

[0240] 1), the identification of the tracking area where the terminal device is located;

[0241] 2), the IMSI number segment corresponding to the terminal device;

[0242] 3), the subscribed slice of the terminal device;

[0243] 4), the usage category of the terminal device;

[0244] 5), the cell to which the terminal device is connected.

[0245] Figure 10 It is a schematic diagram of the interface between mobility management network elements. There can be an N14 interface between different mobility management network elements. Therefore, the first mobility management network element can send a first redirect request message to the second mobility management network element through the N14 interface.

[0246] Step 902, the second mobility management network element sends a redirect response message to the first mobility management network element. Correspondingly, the first mobility management network element receives the redirect response message.

[0247] The second mobility management network element can send a redirect response message to the first mobility management network element through the N14 interface.

[0248] This redirect response message indicates that the redirect fails. Optionally, the redirect message includes indication information, and the indication information is used to indicate that the second mobility management network element is a standby mobility management network element. Exemplarily, the indication information can be a ProblemDetails string, such as specifically backupNE.

[0249] When the second mobility management network element, which is the primary mobility management network element, fails to work properly due to reasons such as a fault, the second mobility management network element switches to a standby mobility management network element, and the third mobility management network element switches to the primary mobility management network element. Therefore, when the second mobility management network element receives the first redirect request message, it rejects the redirect and sends a redirect response message to the first mobility management network element, which is used to indicate that the redirect fails. Optionally, indication information indicating that the second mobility management network element is a standby mobility management network element is also carried in the redirect response message.

[0250] Step 903, the first mobility management network element sends a second redirect request message to the third mobility management network element. Correspondingly, the third mobility management network element receives the second redirect request message.

[0251] Specifically, the first mobility management network element sends a second redirect request message to the third mobility management network element according to the redirect response message or the indication information in the redirect response message. Exemplarily, the first mobility management network element can send a second redirect request message to the third mobility management network element through the N14 interface.

[0252] The second redirection request message includes the identification information of the terminal device, and the second redirection request is used to request redirecting the terminal device to a third mobility management network element.

[0253] After receiving the second redirection request message, the third mobility management network element redirects the terminal device to the third mobility management network element, and sends a redirection response message indicating successful redirection to the first mobility management network element.

[0254] It should be noted that when there is one mobility management network element as the primary mobility management network element and two or more mobility management network elements as the standby mobility management network elements, if the redirection response message received by the first mobility management network element indicates redirection failure, the first mobility management network element can poll and send redirection request messages to other associated mobility management network elements until a redirection response message indicating successful redirection is received.

[0255] In the above solution, when the network after redirection is a primary / standby network, if the roles of the primary mobility management network element and the standby mobility management network element change, the first mobility management network element can also accurately redirect the terminal device to the correct mobility management network element.

[0256] It should be noted that in other implementation methods, after a certain standby mobility management network element among multiple mobility management network elements is promoted to the primary mobility management network element, it can actively send a notification message to the first mobility management network element to indicate the latest primary mobility management network element, so that the first mobility management network element can timely learn the latest primary mobility management network element, which is convenient for subsequent sending of redirection request messages to the correct primary mobility management network element, and can reduce the probability of redirection failure.

[0257] It can be understood that in order to implement the functions in the above embodiments, the terminal device or the first mobility management network element includes corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should easily realize that, combining the units and method steps of each example described in the embodiments disclosed in the present application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application scenarios and design constraints of the technical solution.

[0258] Figure 11 and Figure 12 A schematic structural diagram of a possible communication device provided by an embodiment of the present application. These communication devices can be used to implement the functions of the terminal device or the first mobility management network element in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments. In the embodiments of the present application, the communication device can be a terminal device or a first mobility management network element, or can also be a module (such as a chip) applied to the terminal device or the first mobility management network element.

[0259] Figure 11 The communication device 1100 shown includes a processing unit 1110 and a transceiver unit 1120. The communication device 1100 is used to implement the functions of the terminal device or the first mobility management network element in the above method embodiments.

[0260] When the communication device 1100 is used to implement the functions of the terminal device in the above method embodiments, the processing unit 1110 is used to control the transceiver unit 1120 to send a registration request message, the registration request message includes the identification information of the terminal device, and the registration request message is used to request registration to the network; receive a first GUTI from the first mobility management network element, the first GUTI includes mobility management network element set information, the mobility management network element indicated by the mobility management network element set information belongs to a private network core network and the first mobility management network element belongs to a macro network core network, or, the mobility management network element indicated by the mobility management network element set information and the first mobility management network element belong to different private network core networks, or, the mobility management network element indicated by the mobility management network element set information and the first mobility management network element belong to different macro network core networks; receive a deregistration message from the first mobility management network element, the deregistration message includes indication information, the deregistration message is used to trigger the terminal device to deregister, and the indication information is used to indicate initiating re-registration; according to the indication information, send a re-registration request message, the re-registration request message includes the first GUTI, and the first GUTI is used to select a mobility management network element that provides services for the terminal device.

[0261] In a possible implementation method, the processing unit 1110 is used to control the transceiver unit 1120 to receive a first GUTI from the first mobility management network element, specifically including: being used to control the transceiver unit 1120 to receive a registration acceptance message from the first mobility management network element, and the registration acceptance message includes the first GUTI.

[0262] In a possible implementation method, the processing unit 1110 is configured to control the transceiver unit 1120 to receive a first GUTI from the first mobility management network element, specifically including: being configured to control the transceiver unit 1120 to receive a reallocation command from the first mobility management network element, where the first GUTI is included in the reallocation command.

[0263] When the communication device 1100 is used to implement the function of the first mobility management network element in the above method embodiment, the processing unit 1110 is configured to control the transceiver unit 1120 to receive a registration request message from the terminal device, where the registration request message includes identification information of the terminal device, and the registration request message is used to request registration to the network; send a first GUTI to the terminal device, where the first GUTI includes mobility management network element set information, the mobility management network element indicated by the mobility management network element set information belongs to the private network core network and the first mobility management network element belongs to the macro network core network, or, the mobility management network element indicated by the mobility management network element set information and the first mobility management network element belong to different private network core networks, or, the mobility management network element indicated by the mobility management network element set information and the first mobility management network element belong to different macro network core networks; the first mobility management network element sends a deregistration message to the terminal device, where the deregistration message includes indication information, and the deregistration message is used to trigger the terminal device to deregister, and the indication information is used to indicate initiating reregistration.

[0264] In a possible implementation method, the processing unit 1110 is configured to control the transceiver unit 1120 to send a first GUTI to the terminal device, specifically including: being configured to control the transceiver unit 1120 to send a registration acceptance message to the terminal device, where the first GUTI is included in the registration acceptance message.

[0265] In a possible implementation method, the processing unit 1110 is configured to control the transceiver unit 1120 to send a first GUTI to the terminal device, specifically including: being configured to control the transceiver unit 1120 to send a reallocation command to the terminal device, where the first GUTI is included in the reallocation command.

[0266] In a possible implementation method, the processing unit 1110 is further configured to determine, according to any one or more of the following information, that the terminal device is served by the mobility management network element indicated by the mobility management network element set information: the identifier of the tracking area where the terminal device is located, the IMSI number segment corresponding to the terminal device, the subscribed slice of the terminal device, the usage category of the terminal device, or the cell accessed by the terminal device.

[0267] When the communication device 1100 is used to implement the functions of the first mobility management network element in the above method embodiments, the processing unit 1110 is configured to control the transceiver unit 1120 to send a first redirection request message to the second mobility management network element. The first redirection request message includes the identification information of the terminal device. The first redirection request is used to request redirecting the terminal device to the second mobility management network element; receive a redirection response message from the second mobility management network element, where the redirection response message indicates that the redirection fails; send a second redirection request message to the third mobility management network element. The second redirection request message includes the identification information of the terminal device. The second redirection request is used to request redirecting the terminal device to the third mobility management network element; where the second mobility management network element and the third mobility management network element are mutually active and standby mobility management network elements.

[0268] In a possible implementation method, the processing unit 1110 is further configured to determine, according to any one or more of the following information, that the second mobility management network element or the third mobility management network element provides services for the terminal device: the identification of the tracking area where the terminal device is located, the IMSI number segment corresponding to the terminal device, the subscribed slice of the terminal device, the usage category of the terminal device, or the cell accessed by the terminal device.

[0269] In a possible implementation method, the processing unit 1110 is configured to control the transceiver unit 1120 to send a first redirection request message to the second mobility management network element, specifically including: being configured to control the transceiver unit 1120 to send the first redirection request message to the second mobility management network element according to configuration information, where the configuration information indicates that the priority of the second mobility management network element is higher than the priority of the third mobility management network element, or indicates that the second mobility management network element is the active mobility management network element and the third mobility management network element is the standby mobility management network element.

[0270] For a more detailed description of the above processing unit 1110 and transceiver unit 1120, reference can be directly made to the relevant descriptions in the above method embodiments and will not be elaborated here.

[0271] Figure 12 The shown communication device 1200 includes a processor 1210 and an interface circuit 1220. The processor 1210 and the interface circuit 1220 are mutually coupled. It can be understood that the interface circuit 1220 can be a transceiver or an input / output interface. Optionally, the communication device 1200 may further include a memory 1230, configured to store instructions executed by the processor 1210, or store input data required for the processor 1210 to run instructions, or store data generated after the processor 1210 runs instructions.

[0272] When the communication device 1200 is used to implement the above method embodiments, the processor 1210 is used to implement the functions of the above processing unit 1110, and the interface circuit 1220 is used to implement the functions of the above transceiver unit 1120.

[0273] It can be understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0274] The method steps in the embodiments of the present application may be implemented in a hardware manner or by a processor executing software instructions. The software instructions may be composed of corresponding software modules, and the software modules may be stored in a random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, removable hard disk, CD-ROM, or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium may also be a component of the processor. The processor and the storage medium may be located in the ASIC. Additionally, the ASIC may be located in an access network device or a terminal device. Of course, the processor and the storage medium may also exist as discrete components in the access network device or the terminal device.

[0275] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are executed in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, an access network device, a terminal device, or other programmable devices. The computer program or instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer program or instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired or wireless manner. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; it can also be an optical medium, such as a digital video disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium can be a volatile or non-volatile storage medium, or can include both volatile and non-volatile types of storage media.

[0276] In various embodiments of the present application, if there is no special explanation and logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0277] In the present application, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. In the textual description of the present application, the character " / " generally represents an "or" relationship between the associated objects before and after; in the formulas of the present application, the character " / " represents a "division" relationship between the associated objects before and after.

[0278] It can be understood that the various numerical numbers involved in the embodiments of the present application are only for convenience of description and are not used to limit the scope of the embodiments of the present application. The magnitude of the sequence numbers of the above processes does not mean the order of execution. The order of execution of each process should be determined by its function and internal logic.< / mmec> < / mmegi> < / mnc> < / mcc> < / gummei> < / gummei> < / mnc> < / mcc> < / guami> < / guami>

Claims

1. A communication method, characterized in that, Applied to a first mobility management network element, the method includes: Sending a first redirection request message to a second mobility management network element, where the first redirection request message includes identification information of a terminal device, and the first redirection request is used to request redirecting the terminal device to the second mobility management network element; Receiving a redirection response message from the second mobility management network element, where the redirection response message indicates that the redirection fails; Sending a second redirection request message to a third mobility management network element, where the second redirection request message includes the identification information of the terminal device, and the second redirection request is used to request redirecting the terminal device to the third mobility management network element; Wherein, the second mobility management network element and the third mobility management network element are mutually active and standby mobility management network elements.

2. The method according to claim 1, wherein The redirection response message includes indication information, and the indication information is used to indicate that the second mobility management network element is a standby mobility management network element.

3. The method according to claim 1, wherein The method further includes: Determining that the terminal device is served by the second mobility management network element or the third mobility management network element according to any one or more of the following information: The identifier of the tracking area where the terminal device is located, the IMSI number segment corresponding to the terminal device, the subscribed slice of the terminal device, the usage category of the terminal device, or the cell accessed by the terminal device.

4. The method according to claim 2, wherein The method further includes: Determining that the terminal device is served by the second mobility management network element or the third mobility management network element according to any one or more of the following information: The identifier of the tracking area where the terminal device is located, the IMSI number segment corresponding to the terminal device, the subscribed slice of the terminal device, the usage category of the terminal device, or the cell accessed by the terminal device.

5. The method according to any one of claims 1 to 4, characterized in that, The sending the first redirection request message to the second mobility management network element includes: Sending the first redirection request message to the second mobility management network element according to configuration information, where the configuration information indicates that the priority of the second mobility management network element is higher than the priority of the third mobility management network element, or indicates that the second mobility management network element is the active mobility management network element and the third mobility management network element is the standby mobility management network element.

6. A communication device, characterized in that, Includes a module for executing the method according to any one of claims 1 to 5.

7. A computer program product, characterized in that, The computer program product includes instructions, and when the instructions run on a processor, the processor is caused to execute the method according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, A computer program or instructions are stored in the storage medium, and when the computer program or instructions are executed by a communication device, the method according to any one of claims 1 to 5 is implemented.

9. A communication system, characterized in that, Includes: A first mobility management network element, configured to send a first redirection request message to a second mobility management network element, where the first redirection request message includes identification information of a terminal device, and the first redirection request is used to request redirecting the terminal device to the second mobility management network element; receiving a redirection response message from the second mobility management network element, where the redirection response message indicates that the redirection fails; And sending a second redirection request message to a third mobility management network element, where the second redirection request message includes identification information of the terminal device, and the second redirection request is used to request redirecting the terminal device to the third mobility management network element; wherein, the second mobility management network element and the third mobility management network element are mutually active and standby mobility management network elements; The second mobility management network element is configured to receive the first redirection request message; and send the redirection response message; The third mobility management network element is configured to receive the second redirection request message.

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