WO2019113981A1 - Switching ensuring method, terminal device, and network device - Google Patents

Abstract

The embodiments of the present application provide a switching ensuring method, a terminal device, and a network device. When there is no N26 interface between a 5GC and an EPC and the terminal device cannot determine whether the network device supports the absence of the N26 interface, the terminal device initiates an attach procedure carrying a switching identifier, thereby ensuring the consistency of IP addresses of a session. The method comprises: when the terminal device accesses a second network from a first network, the terminal device sending a TAU request message to the network device, the TAU request message comprising GUTI information, the network device being used for the second network, the first network and the second network being networks under different communication protocol versions; the terminal device receiving a TAU reject message sent by the network device with respect to the TAU request message; and after receiving the TAU reject message, the terminal device sending, to the network device, an attach request carrying the switching identifier.

Description

Method for guaranteeing handover, terminal device and network device Technical field

The present application relates to the field of communications, and more particularly, to a method, a terminal device, and a network device that guarantee handover.

Background technique

After the terminal equipment moves from the 5G New Radio (NR) network to the 4G Long Term Evolution (LTE) network, it needs to switch from the 5G core network (5G Core, 5GC) to the packet core evolution (Evolved Packet Core). , EPC) devices that can be switched across the system (N26) interface or when there is no N26 interface. At this stage, when there is no N26 interface between the 5GC and the EPC, if the terminal device cannot determine whether the network device supports the switch without the N26 interface, the attach process initiated by the terminal device cannot guarantee the Internet protocol of the session (Internet Protocol, IP) Address consistency.

Summary of the invention

The embodiment of the present application provides a method for guaranteeing handover, a terminal device, and a network device. When there is no N26 interface between the 5GC and the EPC, and the terminal device cannot determine whether the network device supports the N26-free interface, the terminal device initiates the handover identifier. The attach process, thereby ensuring the consistency of the session's IP address.

In a first aspect, the embodiment of the present application provides a method for guaranteeing handover, including:

When the terminal device accesses the second network to the second network, the terminal device sends a Tracking Area Update (TAU) request message to the network device, where the TAU request message includes a globally unique temporary user identifier (Globally Unique Temporary UE) Identity, GUTI) information, the network device is a network device for the second network, the first network and the second network are networks under different communication protocol versions;

Receiving, by the terminal device, a TAU reject message sent by the network device for the TAU request message;

After receiving the TAU reject message, the terminal device sends an attach request carrying the handover identifier to the network device.

Therefore, in the method for ensuring handover in the embodiment of the present application, after the terminal device accesses the second network from the first network, after receiving the TAU reject message sent by the network device, the terminal device sends the carrying handover identifier to the network device. The attach request, so that the network device in the second network can select the network element serving the PDU/PDN session of the first network, thereby ensuring the consistency of the IP address of the session.

Optionally, in an implementation manner of the first aspect, the TAU reject message includes a cause value indicating that the network device cannot identify the GUTI information and/or the network device does not support no cross-system interface communication;

The terminal device sends an attach request carrying the handover identifier to the network device, including:

The terminal device sends the attach request to the network device according to the cause value.

Optionally, in an implementation manner of the first aspect, the TAU reject message includes first indication information, where the first indication information is used to trigger the terminal device to send the attach request to the network device.

The terminal device sends an attach request carrying the handover identifier to the network device, including:

The terminal device sends the attach request to the network device according to the first indication information.

Optionally, in an implementation manner of the first aspect, the attach request includes, for a Packet Data Unit (PDU)/Packet Data Network (PDN) session in the first network. Access Point Name (APN) or Destination Network Name (DNN).

Optionally, in an implementation manner of the first aspect, the TAU request message includes second indication information, where the second indication information is used to indicate that the terminal device accesses the second network from the first network.

Optionally, in an implementation manner of the first aspect, the GUTI information indicates that the terminal device accesses the second network from the first network.

Optionally, in an implementation manner of the first aspect, the GUTI information is a second GUTI, the second GUTI is a GUTI for the second network, and the second GUTI is according to the first GUTI, the first GUTI A mapping relationship with the second GUTI is obtained, and the first GUTI is a GUTI for the first network.

Optionally, in an implementation manner of the first aspect, the attach request further includes a third GUTI or a fourth GUTI, so that the network device determines, according to the third GUTI or the fourth GUTI, the terminal device from the first a network accessing the second network, wherein

The third GUTI is a GUTI for the second network, and the third GUTI is obtained according to a mapping relationship between the first GUTI, the first GUTI, and the third GUTI, where the first GUTI is a GUTI for the first network. ;

The fourth GUTI is a GUTI for the second network stored in the terminal device.

Optionally, in an implementation manner of the first aspect, the terminal device cannot determine whether the network device supports no cross-system interface communication.

Optionally, in an implementation manner of the first aspect, the first network is an NR network, the second network is an LTE network, and the network device is an MME device.

In a second aspect, the embodiment of the present application provides a method for guaranteeing handover, including:

The network device receives a TAU request message sent by the terminal device, where the TAU request message includes GUTI information, where the network device is a network device for the second network;

When the network device cannot parse the GUTI information, send a TAU reject message for the TAU request message to the terminal device;

Receiving, by the network device, an attach request that carries the handover identifier sent by the terminal device;

After receiving the attach request, the network device determines to serve a network element for a packet data unit PDU/packet data network PDN session in the first network, the first network and the second network being under different communication protocol versions The internet.

Therefore, in the method for ensuring handover in the embodiment of the present application, after the terminal device accesses the second network from the first network, after receiving the TAU reject message sent by the network device, the terminal device sends the carrying handover identifier to the network device. The attach request, so that the network device in the second network can select the network element serving the PDU/PDN session of the first network, thereby ensuring the consistency of the IP address of the session.

Optionally, in an implementation manner of the second aspect, the TAU reject message includes a cause value indicating that the network device cannot identify the GUTI information and/or the network device does not support no cross-system interface communication.

Optionally, in an implementation manner of the second aspect, the TAU reject message includes first indication information, where the first indication information is used to trigger the terminal device to send the attach request to the network device.

Optionally, in an implementation manner of the second aspect, the attach request includes an access point name APN or a target network name DNN corresponding to the PDU/PDN session;

The network device determines a network element serving the PDU/PDN session in the first network, including:

The network device determines a network element serving the PDU/PDN session based on the APN or DNN.

Optionally, in an implementation manner of the second aspect, the TAU request message includes second indication information, where the second indication information is used to indicate that the terminal device accesses the second network from the first network;

The method also includes:

The network device determines, according to the second indication information, that the terminal device accesses the second network from the first network.

Optionally, in an implementation manner of the second aspect, the GUTI information indicates that the terminal device moves from the first network to the second network;

The method also includes:

The network device determines, according to the GUTI information, that the terminal device accesses from the first network to the second network.

Optionally, in an implementation manner of the second aspect, the GUTI information is a second GUTI, the second GUTI is a GUTI for the second network, and the second GUTI is according to the first GUTI, the first GUTI A mapping relationship with the second GUTI is obtained, and the first GUTI is a GUTI for the first network.

Optionally, in an implementation manner of the second aspect, the attach request further includes a third GUTI or a fourth GUTI, where the third GUTI is a GUTI for the second network, and the third GUTI is based on A mapping relationship between the first GUTI, the first GUTI, and the third GUTI is obtained. The first GUTI is a GUTI for the first network, and the fourth GUTI is a GUTI for the second network stored in the terminal device. ;

The method also includes:

The network device determines, according to the third GUTI or the fourth GUTI, that the terminal device accesses from the first network to the second network.

Optionally, in an implementation manner of the second aspect, the first network is an NR network, the second network is an LTE network, and the network device is an MME device.

The network device determines a network element serving the PDU/PDN session in the first network, including:

After determining that the terminal device accesses the LTE network from the NR network, the MME device sends a request message that does not carry the initial attachment identifier to the HSS+UDM device, where the request message is used to request to obtain subscription data for the terminal device;

The MME device obtains, from the HSS+UDM device, an identifier of an SMF+PGW-C device serving the PDU/PDN session and an APN or DNN corresponding to the SMF+PGW-C device;

The MME device determines the SMF+PGW-C device according to the identifier of the SMF+PGW-C device and the APN or DNN corresponding to the SMF+PGW-C device, so that the SMF+PGW-C device maps to the LTE network. Service Message (SM) context.

In a third aspect, the embodiment of the present application provides a terminal device, which can execute the module or unit of the method in the first aspect or any optional implementation manner of the first aspect.

In a fourth aspect, the embodiment of the present application provides a network device, which can execute the module or unit of the method in any of the optional implementations of the second aspect or the second aspect.

In a fifth aspect, a terminal device is provided, the terminal device comprising a processor, a memory, and a communication interface. The processor is coupled to the memory and communication interface. The memory is for storing instructions for the processor to execute, and the communication interface is for communicating with other network elements under the control of the processor. When the processor executes the instructions stored by the memory, the execution causes the processor to perform the method of the first aspect or any of the possible implementations of the first aspect.

In a sixth aspect, a network device is provided, the network device comprising a processor, a memory, and a communication interface. The processor is coupled to the memory and communication interface. The memory is for storing instructions for the processor to execute, and the communication interface is for communicating with other network elements under the control of the processor. When the processor executes the instructions stored by the memory, the execution causes the processor to perform the method of any of the possible implementations of the second aspect or the second aspect.

In a seventh aspect, a computer storage medium is provided having stored therein program code for instructing a computer to execute instructions of the methods described in the above aspects.

In an eighth aspect, a computer program product comprising instructions, when executed on a computer, causes the computer to perform the methods described in the various aspects above.

DRAWINGS

FIG. 1 shows a wireless communication system to which the embodiment of the present application is applied.

FIG. 2 is a schematic flowchart of a method for securing handover according to an embodiment of the present application.

FIG. 3 is a schematic flowchart of a method for securing handover according to another embodiment of the present application.

FIG. 4 is a schematic flowchart of a handover method according to an embodiment of the present application.

FIG. 5 is a schematic block diagram of a terminal device according to an embodiment of the present application.

FIG. 6 is a schematic block diagram of a network device according to an embodiment of the present application.

FIG. 7 is a schematic block diagram of an apparatus for guaranteeing handover provided by an embodiment of the present application.

FIG. 8 is a schematic structural diagram of a system chip according to an embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described in the following with reference to the accompanying drawings in the embodiments.

The technical solution of the embodiment of the present application can be applied to a 5G NR communication system.

FIG. 1 shows a wireless communication system 100 to which an embodiment of the present application is applied. The wireless communication system 100 can include an access network device 120 and an access network device 130. Access network device 120 and access network device 130 may be devices that communicate with the terminal device. Illustrated below by access network device 120, access network device 120 can provide communication coverage for a particular geographic area and can communicate with terminal devices (e.g., UEs) located within the coverage area.

Optionally, the access network device 120 may be an evolved base station (eNB or eNodeB) in an LTE system, for example, an Evolved Universal Terrestrial Radio Access Network (E-UTRAN). device.

Optionally, the access network device 130 may be a Next Generation Radio Access Network (NG RAN), or a base station (gNB) in the NR system, or a cloud radio access network (Cloud Radio). The wireless controller in the Access Network, CRAN), or the access network device may be a relay station, an access point, an in-vehicle device, a wearable device, or a future evolved public land mobile network (PLMN). Network equipment, etc.

The wireless communication system 100 also includes at least one terminal device 110 located within the coverage of the access network device 120 and the access network device 130. Terminal device 110 can be mobile or fixed. Optionally, the terminal device 110 may refer to an access terminal, a user equipment (User Equipment, UE), a subscriber unit, a subscriber station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, and a wireless communication. Device, user agent, or user device. The access terminal may be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), with wireless communication. A functional handheld device, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a 5G network, or a terminal device in a future evolved PLMN, or the like.

The wireless communication system 100 also includes a core network device 140 in communication with the access network device 120, and a core network device 150 in communication with the access network device 130. Optionally, the core network device 140 may be an Evolved Packet Core (EPC) device of the LTE network, for example, a core network side data gateway + session management function (Core Packet Gateway Session Management Function, PGW-C+) SMF) device, User Packet Gateway User Plane Function (PGW-U+UPF), Home Subscriber Server (HSS). Optionally, the core network device 150 may be a 5GC device, for example, an Access and Mobility Management Function (AMF), and, for example, a Session Management Function (SMF), unified data management. (Unified Data Management, UDM).

The core network device 140 and the core network device 150 can communicate through the N26 interface.

Optionally, when the terminal device 110 moves from the 5G network to the 4G network, and the N26 interface exists between the core network device 140 and the core network device 150, cross-system switching can be implemented through the N26 interface.

Alternatively, when the terminal device 110 moves from the 5G network to the 4G network, and the N26 interface does not exist between the core network device 140 and the core network device 150, the cross-system handover can be implemented by the Attach procedure carrying the handover identifier.

Optionally, in the embodiment of the present application, the AMF may perform information interaction with the SMF. For example, the SMF obtains information on the radio access network side from the AMF.

FIG. 1 exemplarily shows two access network devices, two core network devices and one terminal device. Alternatively, the wireless communication system 100 may comprise a plurality of access network devices and each of the access network devices Other numbers of terminal devices may be included in the coverage, which is not limited in this embodiment of the present application.

Optionally, the wireless communication system 100 may further include a Mobile Management Entity (MME), a Unified Data Management (UDM), an Authentication Server Function (AUSF), and a user plane function (User). Plane Function (UPF), Signaling Gateway (SGW), Core Network Gateway (PGW-C), User-side Data Gateway (PGW-U), Home Subscriber Server Other network entities, such as the Home Subscriber Server Unified Data Management (HSS+UDM), are not limited in this embodiment of the present application.

It should be understood that PGW-C+SMF can realize the functions that SMF and PGW-C can achieve at the same time. PGW-U+UPF can realize the functions that PGW-U and UPF can achieve at the same time. HSS+UDM can realize both HSS and UDM. The functions that can be achieved.

It should be understood that the terms "system" and "network" are used interchangeably herein. The term "and/or" in this context is merely an association describing the associated object, indicating that there may be three relationships, for example, A and / or B, which may indicate that A exists separately, and both A and B exist, respectively. B these three situations. In addition, the character "/" in this article generally indicates that the contextual object is an "or" relationship.

FIG. 2 is a schematic flowchart of a method 200 for securing handover according to an embodiment of the present application. The method 200 is optionally applicable to the system shown in FIG. 1, but is not limited thereto. The method 200 includes at least some of the following.

210. When the terminal device accesses the second network to the second network, the terminal device sends a TAU request message to the network device, where the TAU request message includes GUTI information, where the network device is a network device for the second network, The first network and the second network are networks under different communication protocol versions.

Optionally, the first network is a 5G NR network, and the second network is a 4G LTE network.

Optionally, the network device is an MME device.

It should be understood that after the terminal device accesses from the 5G NR network to the 4G LTE network, and the terminal device cannot determine whether the MME supports no N26 interface communication, the TAU process is triggered (a TAU request message is sent to the network device).

Optionally, the GUTI information indicates that the terminal device accesses from the 5G NR network to the 4G LTE network.

Optionally, the GUTI information is a second GUTI, the second GUTI is a GUTI for the second network, and the second GUTI is obtained according to a mapping relationship between the first GUTI, the first GUTI, and the second GUTI, The first GUTI is a GUTI for the first network.

Specifically, the GUTI information may be a 4G GUTI mapped from a 5G GUTI.

Optionally, the TAU request message further includes second indication information, where the second indication information is used to indicate that the terminal device accesses the 5G NR network from the 5G NR network.

220. The terminal device receives a TAU reject message sent by the network device for the TAU request message.

The TAU reject message is a response message for the TAU request message.

Optionally, after the network device (MME device) fails to parse the GUTI information carried in the TAU request message, the TAU reject message is sent to the terminal device.

Optionally, when the network device (MME device) does not support the N26 interface communication, the TAU reject message is sent to the terminal device.

Optionally, the TAU reject message includes a cause value indicating that the network device (MME device) cannot identify the GUTI information and/or the network device (MME device) does not support no cross-system interface communication. Optionally, the terminal device triggers sending an attach request to the network device (MME device) (for forwarding by E-UTRAN) according to the cause value.

Optionally, the TAU reject message includes first indication information, and the first indication information is used to trigger the terminal device to send an attach request to the network device (MME device) (for forwarding by E-UTRAN).

230. After receiving the TAU reject message, the terminal device sends an attach request carrying the handover identifier to the network device.

Optionally, the handover identifier is carried in a PDN connection request parameter in the attach request.

Optionally, the attach request includes an APN or DNN corresponding to a PDU/PDN session in the 5G NR network.

Optionally, the attach request further includes a third GUTI or a fourth GUTI, so that the network device determines, according to the third GUTI or the fourth GUTI, that the terminal device accesses from the first network to the second network, where ,

The third GUTI is a GUTI for the second network, and the third GUTI is obtained according to a mapping relationship between the first GUTI, the first GUTI, and the third GUTI, where the first GUTI is a GUTI for the first network. ;

The fourth GUTI is a GUTI for the second network stored in the terminal device.

Specifically, the attach request further includes a 4G GUTI mapped from the 5G GUTI, or a GUTI (Native 4G GUTI) for the 4G LTE network stored in the UE.

Optionally, the terminal device sends the attach request to the network device according to the cause value.

Optionally, the terminal device sends the attach request to the network device according to the first indication information.

Optionally, the attach request includes an APN or DNN corresponding to a PDU/PDN session in the first network (5G NR network).

Therefore, in the method for ensuring handover in the embodiment of the present application, after the terminal device accesses the second network from the first network, after receiving the TAU reject message sent by the network device, the terminal device sends the carrying handover identifier to the network device. The attach request, so that the network device in the second network can select the network element serving the PDU/PDN session of the first network, thereby ensuring the consistency of the IP address of the session.

FIG. 3 is a schematic flowchart of a method 300 for securing handover according to an embodiment of the present application. The method 300 can optionally be applied to the system shown in Figure 1, but is not limited thereto. The method 300 includes at least a portion of the following.

310. The network device receives a TAU request message sent by the terminal device, where the TAU request message includes GUTI information, where the network device is a network device for the second network.

Optionally, the TAU request message includes second indication information, where the second indication information is used to indicate that the terminal device accesses the second network from the first network.

Optionally, the GUTI information indicates that the terminal device moves from the first network to the second network.

Optionally, the GUTI information is a second GUTI, the second GUTI is a GUTI for the second network, and the second GUTI is obtained according to a mapping relationship between the first GUTI, the first GUTI, and the second GUTI, The first GUTI is a GUTI for the first network.

320. When the network device cannot parse the GUTI information, send a TAU reject message for the TAU request message to the terminal device.

Optionally, the TAU reject message includes a cause value indicating that the network device cannot recognize the GUTI information and/or the network device does not support no cross-system interface communication.

Optionally, the TAU reject message includes first indication information, where the first indication information is used to trigger the terminal device to send the attach request to the network device.

330. The network device receives an attach request that carries the handover identifier sent by the terminal device.

Optionally, the attach request includes an APN or a DNN corresponding to the PDU/PDN session.

Optionally, the attach request further includes a third GUTI or a fourth GUTI, where the third GUTI is a GUTI for the second network, and the third GUTI is according to the first GUTI, the first GUTI, and the third GUTI The mapping relationship is obtained. The first GUTI is a GUTI for the first network, and the fourth GUTI is a GUTI for the second network stored in the terminal device.

340. After receiving the attach request, the network device determines to serve a network element for a PDU/PDN session in the first network, where the first network and the second network are networks under different communication protocol versions.

Optionally, the first network is a 5G NR network, and the second network is a 4G LTE network.

Optionally, the network device is an MME device.

It should be understood that after the terminal device accesses from the 5G NR network to the 4G LTE network, and the terminal device cannot determine whether the MME supports no N26 interface communication, the TAU process is triggered (a TAU request message is sent to the network device).

Optionally, the network device can determine that the terminal device accesses the second network from the first network by:

In a first mode, the network device determines, according to the second indication information, that the terminal device accesses the second network from the first network.

In the second mode, the network device determines, according to the GUTI information, that the terminal device accesses the second network from the first network.

In a third manner, the network device determines, according to the third GUTI or the fourth GUTI, that the terminal device accesses the second network from the first network.

Optionally, the network device (MME device) triggers an E-UTRAN initial attach after receiving the attach request, thereby determining to serve the network element for the PDU/PDN session in the 5G NR network.

Optionally, the network element serving the PDU/PDN session in the 5G NR network may be determined by:

In a first method, after determining that the UE accesses the 4G LTE network from the 5G NR network, the MME device sends a request message that does not carry the initial attachment identifier to the HSS+UDM device, where the request message is used to request to obtain subscription data for the UE.

The MME device obtains, from the HSS+UDM device, an identifier of the SMF+PGW-C device serving the PDU/PDN session and an APN or DNN corresponding to the SMF+PGW-C device;

The MME device determines the SMF+PGW-C device according to the identifier of the SMF+PGW-C device and the APN or DNN corresponding to the SMF+PGW-C device, so that the SMF+PGW-C device maps to the LTE network. SM context.

Manner 2: After determining that the UE accesses the 4G LTE network from the 5G NR network, the MME determines the SMF+PGW according to the APN or DNN corresponding to the PDU/PDN session in the 5G NR network included in the attach request. a -C device to cause the SMF+PGW-C device to map out the SM context for the LTE network.

In the third mode, the SMF+PGW-C device is determined by combining the first mode and the second mode.

Optionally, the SMF+PGW-C device maps the SM context for the LTE network, thereby implementing consistency of the IP address during the handover process.

Therefore, in the method for ensuring handover in the embodiment of the present application, after the terminal device accesses the second network from the first network, after receiving the TAU reject message sent by the network device, the terminal device sends the carrying handover identifier to the network device. The attach request, so that the network device in the second network can select the network element serving the PDU/PDN session of the first network, thereby ensuring the consistency of the IP address of the session.

As an embodiment, as shown in FIG. 4, the terminal device completes registration in a 5G system (5G System, 5GS), and when it is impossible to determine whether the network device supports no N26 interface communication, the terminal device accesses from the 5G NR network to the 4G network. LTE network, specifically, a schematic flowchart of a handover method of a terminal device from a 5GS access to an Evolved Packet System (EPS).

410. The UE triggers a TAU process.

It should be understood that the TAU procedure is triggered when the UE accesses from the 5G NR network to the 4G LTE network, and the UE cannot determine whether the target MME supports no N26 interface communication.

For example, the UE moves from the 5G NR network coverage area to the 4G LTE network coverage area, at which time the UE needs to access from the 5G NR network to the 4G LTE network.

For another example, the UE is in the 5G NR network and the 4G LTE network coverage area at the same time. At this time, the UE abandons the 5G NR network access and selects to access the 4G LTE network.

It should be understood that the UE completes registration in the 5GS, then the NG RAN (gNB), the source MME/AMF, the PGW-C+SMF, and the PGW-U+UPF serve the UE.

Optionally, the UE cannot determine whether the target MME supports no N26 interface communication, and then the TAU process is triggered according to the target MME does not support no N26 interface communication.

420. The UE sends a TAU request (request) message to the E-UTRAN (eNB).

Optionally, the TAU request message includes GUTI information indicating that the UE accesses from the 5G NR network to the 4G LTE network.

Specifically, the GUTI information may be a 4G GUTI mapped from a 5G GUTI.

Optionally, the TAU request message further includes second indication information, where the second indication information is used to indicate that the UE accesses the 5G NR network from the 5G NR network.

It should be understood that the TAU request message may also include other information, such as the UE identity, which is not limited by the embodiment of the present application.

It should also be understood that the TAU request message ultimately needs to be sent to the target MME, the E-UTRAN performs the forwarding operation, and the E-UTRAN does not process the TAU request message.

430. The E-UTRAN sends the TAU request message to the target MME.

It should be understood that the target MME is a core network element serving the UE after the UE moves to the 4G network.

440. The target MME sends a TAU reject message to the UE.

The TAU reject message is a response message for the TAU request message.

Optionally, after the target MME fails to parse the GUTI information carried in the TAU request message, the target MME sends the TAU reject message to the UE.

Optionally, when the target MME does not support the N26 interface communication, the TAU reject message is sent to the UE.

Optionally, the TAU reject message includes a cause value indicating that the target MME cannot identify the GUTI information and/or the target MME does not support no cross-system interface communication. Optionally, the UE triggers an attach request to the target MME (for forwarding by E-UTRAN) according to the cause value.

Optionally, the TAU reject message includes first indication information, and the first indication information is used to trigger the UE to send an attach request to the target MME (for forwarding by E-UTRAN).

450. The UE sends an attach request carrying the handover identifier to the E-UTRAN.

Optionally, the handover identifier is carried in a PDN connection request parameter in the attach request.

Optionally, the attach request includes an APN or DNN corresponding to a PDU/PDN session in the 5G NR network.

Optionally, the attach request further includes a 4G GUTI mapped from the 5G GUTI, or a GUTI (Native 4G GUTI) for the 4G LTE network stored in the UE.

460. The E-UTRAN sends the attach request to the target MME.

Optionally, the target MME determines, according to the GUTI information included in the TAU request message, that the UE accesses from the 5G NR network to the 4G LTE network.

Optionally, the target MME determines, according to the second indication information included in the TAU request message, that the UE accesses the 5G NR network from the 5G NR network.

Optionally, the target MME determines that the UE accesses the 5G NR network to the 4G LTE network according to the 4G GUTI mapped from the 5G GUTI or the GUTI (Native 4G GUTI) for the 4G LTE network stored in the UE.

470, E-UTRAN initial attachment.

The target MME triggers an E-UTRAN initial attach after receiving the attach request.

Optionally, the network element serving the PDU/PDN session in the 5G NR network may be determined by:

In a first method, after determining that the UE accesses the 4G LTE network from the 5G NR network, the target MME device sends a request message that does not carry the initial attachment identifier to the HSS+UDM device, where the request message is used to request to obtain subscription data for the UE.

The target MME device obtains, from the HSS+UDM device, an identifier of the SMF+PGW-C device serving the PDU/PDN session and an APN or DNN corresponding to the SMF+PGW-C device;

The target MME device determines the SMF+PGW-C device according to the identifier of the SMF+PGW-C device and the APN or DNN corresponding to the SMF+PGW-C device, so that the SMF+PGW-C device maps to the LTE network. The SM context.

Manner 2, after determining that the UE accesses the 4G LTE network from the 5G NR network, the target MME determines the SMF+ according to the APN or DNN corresponding to the PDU/PDN session in the 5G NR network included in the attach request. PGW-C device to map the SMF+PGW-C device out of the SM context for the LTE network.

In the third mode, the SMF+PGW-C device is determined by combining the first mode and the second mode.

480. The UE requests a PDN connection.

The SMF+PGW-C device maps the SM context for the LTE network, thereby achieving consistency of IP addresses during handover.

FIG. 5 is a schematic block diagram of a terminal device 500 according to an embodiment of the present application. As shown in FIG. 5, the terminal device 500 includes a communication unit 510;

The communication unit 510 is configured to: when the terminal device 500 accesses the second network from the first network, send a tracking area update TAU request message to the network device, where the TAU request message includes global unique temporary user identifier GUTI information, the network device For the network device of the second network, the first network and the second network are networks under different communication protocol versions;

The communication unit 510 is further configured to receive a TAU reject message sent by the network device for the TAU request message.

The communication unit 510 is further configured to: after receiving the TAU reject message, send an attach request carrying the handover identifier to the network device.

It should be understood that the terminal device 500 may correspond to the terminal device in the method embodiment, and the corresponding operations implemented by the terminal device in the method embodiment may be implemented. For brevity, no further details are provided herein.

FIG. 6 is a schematic block diagram of a network device 600 in accordance with an embodiment of the present application. As shown in FIG. 6, the network device 600 includes a communication unit 610 and a processing unit 620;

The communication unit 610 is configured to: receive a tracking area update TAU request message sent by the terminal device, where the TAU request message includes global unique temporary user identifier GUTI information, and the network device 600 is a network device for the second network;

The communication unit 610 is further configured to: when the network device 600 cannot parse the GUTI information, send a TAU reject message for the TAU request message to the terminal device;

The communication unit 610 is further configured to receive an attach request that carries the handover identifier sent by the terminal device;

The processing unit 620 is configured to: after the communication unit 610 receives the attach request, determine a network element serving a packet data unit PDU/packet data network PDN session in the first network, the first network And the second network is a network under different communication protocol versions.

It should be understood that the network device 600 may correspond to the network device in the method embodiment, and the corresponding operations implemented by the network device in the method embodiment may be implemented. For brevity, details are not described herein again.

FIG. 7 is a schematic structural diagram of a system chip 700 according to an embodiment of the present application. The system chip 700 of FIG. 7 includes an input interface 701, an output interface 702, the processor 703, and a memory 704 that can be connected by an internal communication connection line. The processor 703 is configured to execute code in the memory 704.

Optionally, when the code is executed, the processor 703 implements a method performed by a terminal device in a method embodiment. For the sake of brevity, it will not be repeated here.

Optionally, when the code is executed, the processor 703 implements a method performed by a network device in a method embodiment. For the sake of brevity, it will not be repeated here.

FIG. 8 is a schematic block diagram of an apparatus 800 for securing handover according to an embodiment of the present application. As shown in FIG. 8, the communication device 800 includes a processor 810 and a memory 820. The memory 820 can store program code, and the processor 810 can execute the program code stored in the memory 820.

Alternatively, as shown in FIG. 8, the communication device 800 can include a transceiver 830 that can control the transceiver 830 to communicate externally.

Optionally, the processor 810 can call the program code stored in the memory 820 to perform the corresponding operations of the terminal device in the method embodiment. For brevity, no further details are provided herein.

Optionally, the processor 810 can call the program code stored in the memory 820 to perform the corresponding operations of the network device in the method embodiment. For brevity, no further details are provided herein.

It should be understood that the processor of the embodiment of the present application may be an integrated circuit chip with signal processing capability. In the implementation process, each step of the foregoing method embodiment may be completed by an integrated logic circuit of hardware in a processor or an instruction in a form of software. The processor may be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a Field Programmable Gate Array (FPGA), or the like. Programming logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps, and logical block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general purpose processor may be a microprocessor or the processor or any conventional processor or the like. The steps of the method disclosed in the embodiments of the present application may be directly implemented by the hardware decoding processor, or may be performed by a combination of hardware and software modules in the decoding processor. The software module can be located in a conventional storage medium such as random access memory, flash memory, read only memory, programmable read only memory or electrically erasable programmable memory, registers, and the like. The storage medium is located in the memory, and the processor reads the information in the memory and combines the hardware to complete the steps of the above method.

It is to be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory may be a read-only memory (ROM), a programmable read only memory (PROM), an erasable programmable read only memory (Erasable PROM, EPROM), or an electric Erase programmable read only memory (EEPROM) or flash memory. The volatile memory can be a Random Access Memory (RAM) that acts as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (Synchronous DRAM). SDRAM), Double Data Rate SDRAM (DDR SDRAM), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM), Synchronous Connection Dynamic Random Access Memory (Synchlink DRAM, SLDRAM) ) and direct memory bus random access memory (DR RAM). It should be noted that the memories of the systems and methods described herein are intended to comprise, without being limited to, these and any other suitable types of memory.

Those of ordinary skill in the art will appreciate that the elements and algorithm steps of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods to implement the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present application.

A person skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the system, the device and the unit described above can refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.

In the several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

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

The functions may be stored in a computer readable storage medium if implemented in the form of a software functional unit and sold or used as a standalone product. Based on such understanding, the technical solution of the present application, which is essential or contributes to the prior art, or a part of the technical solution, may be embodied in the form of a software product, which is stored in a storage medium, including The instructions are used to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like. .

The foregoing is only a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application. It should be covered by the scope of protection of this application. Therefore, the scope of protection of the present application should be determined by the scope of the claims.

Claims (38)

A method for guaranteeing handover, characterized in that it comprises: When the terminal device accesses the second network to the second network, the terminal device sends a tracking area update TAU request message to the network device, where the TAU request message includes global unique temporary user identifier GUTI information, where the network device is targeted a network device of the second network, where the first network and the second network are networks under different communication protocol versions; Receiving, by the terminal device, a TAU reject message sent by the network device for the TAU request message; After receiving the TAU reject message, the terminal device sends an attach request carrying the handover identifier to the network device. The method according to claim 1, wherein the TAU reject message includes a cause value indicating that the network device cannot identify the GUTI information and/or the network device does not support a non-cross system interface Communication The terminal device sends an attach request carrying the handover identifier to the network device, including: The terminal device sends the attach request to the network device according to the cause value. The method according to claim 1 or 2, wherein the TAU reject message includes first indication information, and the first indication information is used to trigger the terminal device to send the attach request to the network device; The terminal device sends an attach request carrying the handover identifier to the network device, including: The terminal device sends the attach request to the network device according to the first indication information. The method according to any one of claims 1 to 3, wherein the attach request comprises an access point name APN corresponding to a packet data unit PDU/packet data network PDN session in the first network Or the target network name DNN. The method according to any one of claims 1 to 4, wherein the TAU request message includes second indication information, and the second indication information is used to indicate that the terminal device is connected from the first network. Enter the second network. The method according to any one of claims 1 to 4, wherein the GUTI information indicates that the terminal device accesses from the first network to the second network. The method according to any one of claims 1 to 6, wherein the GUTI information is a second GUTI, the second GUTI is a GUTI for the second network, and the second GUTI is Obtained according to a mapping relationship between the first GUTI, the first GUTI, and the second GUTI, where the first GUTI is a GUTI for the first network. The method according to any one of claims 1 to 6, wherein the attach request further comprises a third GUTI or a fourth GUTI, such that the network device is according to the third GUTI or the fourth The GUTI determines that the terminal device accesses from the first network to the second network, where The third GUTI is a GUTI for the second network, and the third GUTI is obtained according to a mapping relationship between the first GUTI, the first GUTI, and the third GUTI, where the first GUTI is GUTI of the first network; The fourth GUTI is a GUTI for the second network stored in the terminal device. The method according to any one of claims 1 to 8, wherein the terminal device cannot determine whether the network device supports no cross-system interface communication. The method according to any one of claims 1 to 9, wherein the first network is a new wireless NR network, the second network is a long term evolution LTE network, and the network device is a mobility management entity. MME device. A method for guaranteeing handover, characterized in that it comprises: The network device receives a tracking area update TAU request message sent by the terminal device, where the TAU request message includes global unique temporary user identifier GUTI information, and the network device is a network device for the second network; When the network device cannot parse the GUTI information, send a TAU reject message for the TAU request message to the terminal device; Receiving, by the network device, an attach request that carries the handover identifier sent by the terminal device; After receiving the attach request, the network device determines to serve a network element for a packet data unit PDU/packet data network PDN session in the first network, the first network and the second network being different communications Network under the protocol version. The method according to claim 11, wherein the TAU reject message includes a cause value indicating that the network device cannot identify the GUTI information and/or the network device does not support a non-cross system interface Communication. The method according to claim 11 or 12, wherein the TAU reject message comprises first indication information, and the first indication information is used to trigger the terminal device to send the attach request to the network device. The method according to any one of claims 11 to 13, wherein the attach request includes an access point name APN or a target network name DNN corresponding to the PDU/PDN session; Determining, by the network device, a network element serving a PDU/PDN session in the first network, including: The network device determines a network element serving the PDU/PDN session according to the APN or DNN. The method according to any one of claims 11 to 14, wherein the TAU request message includes second indication information, and the second indication information is used to indicate that the terminal device is connected from the first network. Entering the second network; The method further includes: The network device determines, according to the second indication information, that the terminal device accesses from the first network to the second network. The method according to any one of claims 11 to 14, wherein the GUTI information indicates that the terminal device moves from the first network to the second network; The method further includes: The network device determines, according to the GUTI information, that the terminal device accesses from the first network to the second network. The method according to any one of claims 11 to 16, wherein the GUTI information is a second GUTI, the second GUTI is a GUTI for the second network, and the second GUTI is Obtained according to a mapping relationship between the first GUTI, the first GUTI, and the second GUTI, where the first GUTI is a GUTI for the first network. The method according to any one of claims 11 to 14, wherein the attach request further comprises a third GUTI or a fourth GUTI, wherein the third GUTI is a GUTI for the second network, And the third GUTI is obtained according to a mapping relationship between the first GUTI, the first GUTI, and the third GUTI, where the first GUTI is a GUTI for the first network, and the fourth GUTI is stored in the third GUTI. a GUTI for the second network in the terminal device; The method further includes: Determining, by the network device, that the terminal device accesses from the first network to the second network according to the third GUTI or the fourth GUTI. The method according to any one of claims 11 to 18, wherein the first network is a new wireless NR network, the second network is a long term evolution LTE network, and the network device is a mobility management entity. MME device; Determining, by the network device, a network element serving a PDU/PDN session in the first network, including: After determining that the terminal device accesses the LTE network from the NR network, the MME device sends a request message not carrying the initial attachment identifier to the home subscriber server + unified data management HSS+UDM device, where the request message is used to request acquisition. Signing data for the terminal device; Obtaining, by the MME device, the session management function of the PDU/PDN session from the HSS+UDM device, the identifier of the data gateway SMF+PGW-C device on the core network side, and the identifier corresponding to the SMF+PGW-C device APN or DNN; Determining, by the MME device, the SMF+PGW-C device according to the identifier of the SMF+PGW-C device and the APN or DNN corresponding to the SMF+PGW-C device, so that the SMF+PGW-C device The service message SM context for the LTE network is mapped out. A terminal device, comprising: a communication unit, configured to: when the terminal device accesses the second network to the second network, send a tracking area update TAU request message to the network device, where the TAU request message includes global unique temporary user identifier GUTI information, where the network device is For the network device of the second network, the first network and the second network are networks under different communication protocol versions; The communication unit is further configured to receive a TAU reject message sent by the network device for the TAU request message; The communication unit is further configured to: after receiving the TAU reject message, send an attach request carrying the handover identifier to the network device. The terminal device according to claim 20, wherein the TAU reject message includes a cause value indicating that the network device cannot identify the GUTI information and/or the network device does not support a non-cross system Interface communication The communication unit is specifically configured to: Sending the attach request to the network device according to the cause value. The terminal device according to claim 20 or 21, wherein the TAU reject message includes first indication information, and the first indication information is used to trigger the terminal device to send the attach request to the network device. ; The communication unit is specifically configured to: And sending the attach request to the network device according to the first indication information. The terminal device according to any one of claims 20 to 22, wherein the attach request includes an access point name corresponding to a packet data unit PDU/packet data network PDN session in the first network APN or target network name DNN. The terminal device according to any one of claims 20 to 23, wherein the TAU request message includes second indication information, and the second indication information is used to indicate that the terminal device is from the first network. Access to the second network. The terminal device according to any one of claims 20 to 23, wherein the GUTI information indicates that the terminal device accesses from the first network to the second network. The terminal device according to any one of claims 20 to 25, wherein the GUTI information is a second GUTI, the second GUTI is a GUTI for the second network, and the second GUTI Obtained according to a mapping relationship between the first GUTI, the first GUTI, and the second GUTI, where the first GUTI is a GUTI for the first network. The terminal device according to any one of claims 20 to 25, wherein the attach request further includes a third GUTI or a fourth GUTI, so that the network device is based on the third GUTI or the The fourth GUTI determines that the terminal device accesses from the first network to the second network, where The third GUTI is a GUTI for the second network, and the third GUTI is obtained according to a mapping relationship between the first GUTI, the first GUTI, and the third GUTI, where the first GUTI is GUTI of the first network; The fourth GUTI is a GUTI for the second network stored in the terminal device. The terminal device according to any one of claims 20 to 27, wherein the terminal device cannot determine whether the network device supports no cross-system interface communication. The terminal device according to any one of claims 20 to 28, wherein the first network is a new wireless NR network, the second network is a long term evolution LTE network, and the network device is mobility management. Entity MME device. A network device, comprising: a communication unit, configured to receive a tracking area update TAU request message sent by the terminal device, where the TAU request message includes global unique temporary user identifier GUTI information, where the network device is a network device for the second network; The communication unit is further configured to: when the network device cannot parse the GUTI information, send a TAU reject message for the TAU request message to the terminal device; The communication unit is further configured to receive an attach request that carries the handover identifier sent by the terminal device; a processing unit, configured to determine, after the communication unit receives the attach request, a network element serving a packet data unit PDU/packet data network PDN session in a first network, the first network and the first The second network is a network under different communication protocol versions. The network device according to claim 30, wherein the TAU reject message includes a cause value indicating that the network device cannot identify the GUTI information and/or the network device does not support a non-cross system Interface communication. The network device according to claim 30 or 31, wherein the TAU reject message includes first indication information, and the first indication information is used to trigger the terminal device to send the attach request to the network device. . The network device according to any one of claims 30 to 32, wherein the attach request includes an access point name APN or a target network name DNN corresponding to the PDU/PDN session; The processing unit is specifically configured to: A network element serving the PDU/PDN session is determined according to the APN or DNN. The network device according to any one of claims 30 to 33, wherein the TAU request message includes second indication information, the second indication information is used to indicate that the terminal device is from the first network Accessing to the second network; The processing unit is further configured to: Determining, according to the second indication information, that the terminal device accesses from the first network to the second network. The network device according to any one of claims 30 to 33, wherein the GUTI information indicates that the terminal device moves from the first network to the second network; The processing unit is further configured to: Determining, according to the GUTI information, that the terminal device accesses from the first network to the second network. The network device according to any one of claims 30 to 35, wherein the GUTI information is a second GUTI, the second GUTI is a GUTI for the second network, and the second GUTI Obtained according to a mapping relationship between the first GUTI, the first GUTI, and the second GUTI, where the first GUTI is a GUTI for the first network. The network device according to any one of claims 30 to 33, wherein the attach request further comprises a third GUTI or a fourth GUTI, wherein the third GUTI is a GUTI for the second network And the third GUTI is obtained according to a mapping relationship between the first GUTI, the first GUTI, and the third GUTI, where the first GUTI is a GUTI for the first network, and the fourth GUTI is stored in a GUTI for the second network in the terminal device; The processing unit is further configured to: Determining, according to the third GUTI or the fourth GUTI, that the terminal device accesses from the first network to the second network. The network device according to any one of claims 30 to 37, wherein the first network is a new wireless NR network, the second network is a long term evolution LTE network, and the network device is mobility management. Entity MME device; The processing unit is specifically configured to: After determining that the terminal device accesses the LTE network from the NR network, sending, to the home subscriber server + unified data management HSS+UDM device, a request message that does not carry the initial attachment identifier, where the request message is used to request acquisition for the terminal Equipment contract data; Obtaining, from the HSS+UDM device, a session management function serving the PDU/PDN session, an identifier of a data gateway SMF+PGW-C device on the core network side, and an APN or DNN corresponding to the SMF+PGW-C device; Determining, according to the identifier of the SMF+PGW-C device and the APN or DNN corresponding to the SMF+PGW-C device, the SMF+PGW-C device to map the SMF+PGW-C device to LTE The business message SM context of the network.

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