Network switching method, device and system

Abstract

The invention discloses a network switching method, device and system, and relates to the technical field of communication. When the terminal equipment is switched from the first network equipment to the second network equipment, the mobility registration is abnormal, the duration of the abnormity is within a first preset duration, a mobility registration request is sent to the second network equipment again, the mobility registration request carries first information, and the first information is sent to the second network equipment. The first information is used for the second network equipment to verify the terminal equipment through the first network equipment, and when the exception duration exceeds the first preset duration, an initial registration request is sent to the second network equipment, so that the terminal equipment can perform the mobile registration in the case that the terminal equipment performs the mobile registration exception. And different registration requests are sent to the second network equipment according to different time nodes, so that the problem that the terminal equipment cannot access the network equipment due to the fact that the registration request initiated again when the terminal equipment is in an idle state is abnormal due to link interruption is avoided.

Description

Technical Field

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

[0002] Existing user equipment (UE) can support multiple network modes, such as long term evolution (LTE) and New Radio (NR). In some scenarios, the UE may need to perform network switching, such as switching from an LTE network to an NR network. Currently, during the handover process from LTE to NR in a communication network, there are a large number of cases where the link is abnormal when the UE switches from LTE to NR, resulting in handover failure and the UE returning to the IDLE state. For example, the reasons for the abnormal link when the UE switches from LTE to NR may include, but are not limited to, access failure caused by signal problems, abnormal release of the radio link, etc. The failure of the above network mode switching will seriously affect the user experience. Summary of the Invention

[0003] This application provides a network switching method, device, and system, which can prevent the mobility registration request of the terminal device from being abnormally registered due to link interruption during the mobility registration process of the terminal device.

[0004] To achieve the above object, this application adopts the following technical solutions:

[0005] In a first aspect, a network switching method is provided, which is applied to a terminal device. The method may include:

[0006] First, in response to an abnormal mobility registration when the terminal device switches from a first network device to a second network device, after the terminal device enters the idle state, it sends a mobility registration request to the second network device again. The mobility registration request carries first information, and the first information is used for the second network device to verify the terminal device through the first network device; this step is mainly used for, during the process of the terminal device switching from the first network device to the second network device, when the link is interrupted and the terminal device enters the idle state, the terminal device can send a mobility registration request to the second network device. In the mobility registration request, the first information is carried, and the first information is used for the second network device to verify the terminal device through the first network device when the second network device receives the mobility registration request.

[0007] Then, when the verification is successful, access the second network device. This step is mainly used for, when the second network device receives a mobility registration request, through the first information carried in the mobility registration request, the first network device verifies the terminal device. If the terminal device has accessed the first network device, the terminal device passes the verification and accesses the second network. The solution provided in the first aspect above, in response to an exception occurring during mobility registration when the terminal device switches from the first network device to the second network device, and the duration of the exception is within the first preset duration, sends a mobility registration request to the second network device. The mobility registration request carries the first information, and the first information is used by the second network device to verify the terminal device. In this way, when an exception occurs during the mobility registration of the terminal device, a mobility registration request carrying the first information can be quickly sent to the second network device, so as to avoid the problem that the registration request initiated again when the terminal device is in the idle state due to a link interruption cannot be registered successfully, resulting in the terminal device being unable to access the network device.

[0008] As a possible implementation manner, the method may further include: when the duration of the exception occurring during the mobility registration exceeds the first preset duration, send an initial registration request to the second network device; when the initial registration request is successful, access the second network device. Based on this, after the terminal device sends a mobility registration request to the second network device, if the duration of the exception occurring during the mobility registration of the terminal device is greater than or equal to the first preset duration, it can be considered that the terminal device cannot access the second network device through the mobility registration request. The terminal device can send an initial registration request to the second network device. In some examples, before the terminal device sends an initial registration request to the second network device, it needs to perform local deregistration, that is, the terminal device deletes the context information of the terminal device locally to achieve initial registration on the second network device.

[0009] As a possible implementation, before an abnormality occurs in mobility registration in response to a handover of the terminal device from a first network device to a second network device, the method may further include: during the process of handing over from the first network device to the second network device, sending a mobility registration request to the second network device, where the mobility registration request carries status information of the terminal device and first identification information. Based on this, when the terminal device is accessing the first network device and needs to hand over from the first network device to the second network device, it needs to send a mobility registration request to the second terminal device. Among them, the mobility registration request carries the status information of the terminal device and the first identification information. The second network device can judge through the status information. Exemplarily, when the status information indicates that the terminal device is already registered in the first network device, the second network device determines that the terminal device sending the mobility registration request is from the first network device, and then obtains the context information of the terminal device in the first network device through the first identification information, and completes the mobility registration request of the terminal device.

[0010] As a possible implementation, the mobility registration request also carries the status information and the first identification information, where the status information is used to indicate the registration status of the terminal device in the first network device, and the first identification information is used to indicate the context information of the terminal device in the first network device. Based on this, in the mobility registration request sent by the terminal device, in addition to the status information and the first identification information, it also includes the above-mentioned first information. The second network device can implement the mobility registration request sent in the idle state of the terminal status through the status information, the first identification information, and the first information. In some examples, when the status information indicates that the terminal device is already registered in the first network device, the second network device determines that the terminal device sending the mobility registration request is from the first network device, and based on the first information, verifies the terminal device through the network device. After the verification passes, it can obtain the context information of the terminal device in the first network device through the first identification information, and complete the mobility registration request of the terminal device.

[0011] As a possible implementation manner, the sending of the mobility registration request to the second network device may include: obtaining the tracking area update information of the terminal device, encrypting and integrity-protecting the tracking area update information according to the security context information configured by the terminal device and the first network device to obtain the first information, obtaining the mobility registration request based on the first information, the status information of the terminal device, and the first identification information, and sending the mobility registration request to the second network device. Based on this, when the terminal device is in the idle state, a mobility registration request may be sent to the second network device. The mobility registration request includes the first information, the status information, and the first identification information. The first information may include the tracking area update information, and the tracking area update information may indicate to the second network device that the terminal device comes from the first network device. The second network device may initiate verification of the terminal device to the first network device based on the tracking area update information. After the verification passes, the context information of the terminal device may be obtained from the first network device through the first identification information, and the mobility registration request of the terminal device may be completed.

[0012] As a possible implementation manner, the terminal device maintains a first timer. After an exception occurs in the mobility registration in response to the handover of the terminal device from the first network device to the second network device, the method may further include: when the first timer is in the timeout state, determining that the duration for which the exception in the mobility registration occurs exceeds the first preset duration. Based on this, the first timer in the terminal device may be started when the terminal device begins to hand over from the first network device to the second network device. When an exception occurs in the mobility handover of the terminal device, it is determined whether the first timer is in the timeout state. When the first timer has not timed out, the terminal device may send a mobility registration request to the second network device according to the method in the foregoing embodiment. When the first timer times out, the terminal device may directly send an initial registration request to the second network device.

[0013] As a possible implementation, the first timer is configured according to a second timer maintained in the first network device. Based on this, a second timer is maintained in the first network device. The second timer is used to delete the context information of the terminal device in the first network device after the second timer times out when the terminal device starts mobility registration. The first preset duration corresponding to the first timer can be configured according to the preset duration of the second timer. Exemplarily, the first timer can have the same preset duration as the second timer, or can be configured according to the preset durations of multiple second timers corresponding to multiple first network devices. Among them, the preset durations of the multiple second timers can be the same or different. This is to enable the terminal device to send a mobility registration request when the first network device has not deleted the context information, so that the second network device can obtain the corresponding context information from the first network device, saving the time and resources for establishing context information. When the first network device has already deleted the context information, the terminal device directly sends an initial registration request to the second network device to re-establish context information with the second network device, ensuring that the terminal device can successfully access the second network device.

[0014] In a second aspect, a network switching method is provided, which is applied to a terminal device. The method may include:

[0015] In response to an exception occurring during mobility registration when the terminal device switches from a first network device to a second network device, send an initial registration request to the second network device; when the initial registration request is successful, access the second network device. The solution provided in the second aspect above enables the terminal device to directly send an initial registration request to the second network device and re-establish context information with the second network device when the link is interrupted and the terminal device enters the idle state during the process of the terminal device switching from the first network device to the second network device, so as to achieve the purpose of the terminal device accessing the second network device. This solves the problem that the terminal device cannot access the second network device through a mobility registration request and also avoids the problem that the terminal device still cannot access the second network device after repeatedly attempting to send a mobility registration request to the second network device. In some examples, before sending the initial registration request to the second network device, the terminal device needs to perform local deregistration, that is, the terminal device deletes the context information of the terminal device locally to achieve the problem of initial registration in the second network device.

[0016] As a possible implementation manner, the identity information of the terminal device is carried in the initial registration request, and the identity information is used by the second network device to authenticate the terminal device. Based on this, when the terminal device sends an initial registration request to the second network device, the second network device can authenticate the identity information of the terminal device. After passing the authentication, the terminal device can negotiate further with the second network device to establish new context information to achieve the registration of the terminal device with the second network device.

[0017] In a third aspect, a network switching method is provided, which is applied to a second network device. The method may include:

[0018] First, receive a registration request sent by the terminal device; this step is mainly used to receive the registration request sent by the terminal device. Exemplarily, the registration request may be the mobility registration request in the foregoing embodiment, or may also be an initial registration request. After the second network device receives the registration request, it can obtain the information carried in the registration request.

[0019] Then, obtain the context information corresponding to the terminal device based on the registration request; this step is mainly used for the second network device to obtain the context information corresponding to the terminal device according to the information carried in the registration request. Among them, the information carried in the registration request may be different, and the method for obtaining the context information of the terminal device may also be different.

[0020] Finally, register the terminal device to the second network device based on the context information corresponding to the terminal device; this step is mainly used for, after the second network device obtains the context information of the terminal device, it can establish an association relationship with the terminal device through the context information to achieve the access of the terminal device to the second network device.

[0021] For the solution provided in the above third aspect, after receiving the registration request information, the second network device can determine the corresponding method for obtaining the context of the terminal device according to the different information carried in the registration request, and obtain the context information of the terminal device based on this method. By establishing an association relationship with the context information, the registration process of the terminal device with the second network device is completed. Based on this, the second network device can obtain the context information of the terminal device according to the registration requests sent by the terminal device in different scenarios, and realize the access of the terminal device according to the context information, solving the problem of abnormal registration of the terminal device when accessing the second network device with mobility.

[0022] As a possible implementation manner, after registering the terminal device to the second network device, there is an association relationship between the context information corresponding to the terminal device and the second network device. Based on this, after the terminal device accesses the second network device, there is an association relationship between the context information corresponding to the terminal device and the second network device. In some examples, when the second network device obtains the context information of the terminal device, an association relationship between the second identification information and the context information may be established, and a registration acceptance message is sent to the terminal device.

[0023] As a possible implementation manner, obtaining the context information corresponding to the terminal device based on the registration request may include: sending an identity query request, an authentication request, and a security mode command to the terminal device; creating the context information corresponding to the terminal device when the terminal device responds to the identity query request, the authentication request, and the security mode command. Based on this, when the second network device cannot obtain the context information of the terminal device from the first network device according to the information carried in the registration request, the second network device may directly request the terminal device to re-establish the context information. In some examples, an identity query request, an authentication request, and a security mode command may be sent to the terminal device, and after the terminal device respectively responds to the identity query request, the authentication request, and the security mode command, the second network device obtains the context information corresponding to the terminal device. In some examples, that the second network device cannot obtain the context information of the terminal device from the first network device according to the information carried in the registration request may include that the terminal device is in the idle state, and the request message carries status information and the first identification information but does not carry the first information, so that the second network device cannot verify the terminal device, and thus cannot obtain the context information of the terminal device from the first network device.

[0024] As a possible implementation manner, the registration request includes the status information, the first identification information, and the first information of the terminal device. Obtaining the context information corresponding to the terminal device based on the registration request may include: when the status information indicates that the registration status of the terminal device in the first network device is registered, verifying the terminal device through the first information; when the verification is successful, obtaining the context information corresponding to the terminal device from the first network device based on the first identification information. Based on this, if the registration request includes status information, the first identification information, and the first information, it can be considered that the registration request is the mobility registration request in the foregoing embodiment. When the status information indicates that the terminal device is already registered in the first network device, the verification information of the terminal device is sent to the first network device according to the tracking area update information carried in the first information. After the verification passes, the context information corresponding to the terminal device is obtained from the first network device through the first identification information.

[0025] As a possible implementation manner, the mobility registration request includes first identification information. Obtaining the context information corresponding to the terminal device based on the registration request may include: obtaining the context information corresponding to the terminal device from the stored information based on the first identification information. Based on this, the second network device may perform local addressing according to the first identification information to obtain the context information of the terminal device, where an association relationship between the first identification information and the context information is stored locally in the second network device.

[0026] As a possible implementation manner, the method may further include: receiving the context information corresponding to the terminal device from the first network device; storing the association relationship between the first identification information and the context information in the second network device. Based on this, when the second network device receives the context information corresponding to the terminal device sent by the first network device, and when the overhead of the second network device permits, the second network device may store the association relationship between the first identification information and the context information in the second network device, so that when the mobility registration of the terminal device is abnormal and the context information of the terminal device cannot be obtained from the first network device, the context information of the terminal device can be obtained through local addressing in the second network device according to the first identification information.

[0027] As a possible implementation manner, the context information corresponding to the terminal device is sent by the first network device to the second network device before the terminal device switches from the first network device to the second network device. Based on this, the first network device may proactively send the context information of the terminal device to the second network device before the network switch, so that the second network device stores the association relationship between the first identification information and the context information.

[0028] In a fourth aspect, a terminal device is provided. The terminal device may include: a transceiver for sending and receiving signals; a memory for storing computer program instructions; and a processor for executing the computer program instructions to support the terminal device in implementing the method according to any one of the first aspect or the second aspect.

[0029] In a fifth aspect, a network device is provided. The network device may include: a transceiver for sending and receiving signals; a memory for storing computer program instructions; and a processor for executing the computer program instructions to support the network device in implementing the method according to any one of the third aspect.

[0030] In a sixth aspect, a communication system is provided, which may include a terminal device, a first network device, and a second network device. The communication system is used to implement the method described in any one of the first aspect, the second aspect, or the third aspect.

[0031] In a seventh aspect, a computer-readable storage medium is provided. Computer program instructions are stored on the computer-readable storage medium, and when the computer program instructions are executed by a processing circuit, the method described in any one of the first aspect, the second aspect, or the third aspect is implemented.

[0032] In an eighth aspect, a computer program product including instructions is provided. When the computer program product runs on a computer, the computer is caused to execute the method described in any one of the first aspect, the second aspect, or the third aspect.

[0033] In a ninth aspect, a chip system is provided. The chip system may include a processing circuit and a storage medium. Computer program instructions are stored in the storage medium; when the computer program instructions are executed by the processing circuit, the method described in any one of the first aspect, the second aspect, or the third aspect is implemented. Description of the Drawings

[0034] Figure 1 A schematic flowchart of a network switching method provided for the related art;

[0035] Figure 2 A schematic diagram of the hardware structure of a terminal device or a network device provided for an embodiment of the present application;

[0036] Figure 3 A schematic flowchart of a network switching method for a terminal device provided for an embodiment of the present application;

[0037] Figure 4 A detailed flowchart of a network switching method for a terminal device provided for an embodiment of the present application;

[0038] Figure 5 A schematic flowchart of another network switching method for a terminal device provided for an embodiment of the present application;

[0039] Figure 6 A detailed flowchart of another network switching method for a terminal device provided for an embodiment of the present application;

[0040] Figure 7 A schematic flowchart of yet another network switching method for a terminal device provided for an embodiment of the present application;

[0041] Figure 8 A schematic flowchart of a network switching method for a network device provided for an embodiment of the present application;

[0042] Figure 9 This is a detailed flowchart showing a network switching method for a network device provided by an embodiment of the present application;

[0043] Figure 10 This is a detailed flowchart showing another network switching method for a network device provided by an embodiment of the present application. Detailed implementation manners

[0044] Next, the technical solutions in the embodiments of the present application will be described in conjunction with the accompanying drawings in the embodiments of the present application. Among them, in the description of the embodiments of the present application, unless otherwise specified, " / " means "or". For example, A / B may represent A or B; herein, "and / or" is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality of" means two or more than two.

[0045] Hereinafter, terms such as "first" and "second" are only used to distinguish different described objects, and do not limit the position, order, priority, quantity, content, etc. of the described objects. For example, if the described object is "field", the ordinal numbers before "field" in "first field" and "second field" do not limit the position or order between the "fields", and "first" and "second" do not limit whether the "fields" they modify are in the same message, nor do they limit the order of "first field" and "second field". Another example, if the described object is "level", the ordinal numbers before "level" in "first level" and "second level" do not limit the priority between the "levels". Another example, the quantity of the described object is not limited by the ordinal number and can be one or more. Taking "first device" as an example, the quantity of "device" can be one or more. In addition, the objects modified by different prefix words can be the same or different. For example, if the described object is "device", then "first device" and "second device" can be the same type of device or different types of devices. Another example, if the described object is "information", then "first information" and "second information" can be information with the same content or different content. In short, the use of ordinal numbers and other prefix words for distinguishing described objects in the embodiments of the present application does not constitute a limitation on the described objects. The description of the described objects refers to the description in the claims or the context of the embodiments, and should not constitute unnecessary limitations due to the use of such prefix words.

[0046] In addition, in the embodiments of the present application, "connection" may be a direct connection or an indirect connection; furthermore, it may refer to an electrical connection or a communication connection; for example, when two electrical components A and B are connected, it may mean that A is directly connected to B, or it may mean that A and B are indirectly connected through other electrical components or connection media, or it may mean that A and B are indirectly connected through other communication devices or communication media, as long as communication can be carried out between A and B.

[0047] For ease of understanding, the following first explains the relevant technical terms involved in the embodiments of the present application:

[0048] EPS NAS message container: eps-nas message container, also known as "EPS NAS MSGContainer"; an IE item carried to the network device when the terminal device initiates a registration request. When the terminal device is in the idle state and is reselected from LTE to NR, the information carried in the IE item indicates that the registration request constructs and initiates a request message on the LTE side, and the security context of LTE performs encryption and decryption.

[0049] UE Status: The status information of the terminal device, used to indicate the registration status of the UE. When the UE switches the network from LTE to NR, the UE will carry an IE (Internet Explorer) item, and the IE item is used to indicate to NR that the terminal device comes from LTE.

[0050] Currently, in the handover process from LTE to NR, there are a large number of phenomena where the UE cannot access NR after the handover from LTE to NR. In particular, after the handover from LTE to NR occurs, as long as a link anomaly causes the UE to return to the IDLE state, a registration anomaly will definitely occur in the target network when the UE initiates the inter-system registration process again.

[0051] In some examples, the situation where a link anomaly causes the UE to return to the IDLE state may include: initiating a registration request to access the target cell, failing due to signal problems, triggering the NAS layer to perform a reconstruction Fallabck process, the terminal device initiating a registration request from the IDLE state, and a radio link anomaly release occurring due to poor signal during registration, etc.

[0052] In some examples, refer to Figure 1 , which shows a schematic flowchart of a network handover method provided by the related art. As Figure 1 shown, in the process of implementing the handover from a 4G network to a 5G network, the problems of this method include:

[0053] First, confirm the handover command. When it is determined that the network status for transmitting data via 5GS is available, send a handover notification to the Target AMF via NG-RAN. The reason for the abnormal registration of the UE on NR is that during the handover process from LTE to NR, after receiving the reconfiguration complete notification, the MME starts a timer (exemplarily, this timer can be set to 2s), and after the timer expires, it starts to perform the action of deleting the UE context. The AMF stores the UE context information obtained from the MME using the N2 interface to identify the NGAP ID for addressing. This NGAP ID is related to the link status of the UE. When the UE enters the IDLE state, the link re-established by the UE will be re-allocated a new NGAP ID, resulting in the AMF being unable to find the UE context locally; while the UE believes that the AMF has obtained the UE corresponding context during the handover, and when sending the registration to the core network locally, the core network can also find the UE context based on the 4G Map GUTI (used to identify the UE in the 4G network) carried by us. Therefore, only the UE Status of EMM-REGISTRED is carried during registration to tell the UE that it comes from LTE, but the EPS NAS MSGContainer is not carried because it is considered that the context has been transferred to NR and NR can find it by itself without verifying with LTE. For the core network, in the scenario where the UE status sent by the UE in the IDLE state is EMM-REGISTRED and N26 is supported, it is considered that the EPS NAS MSG Container must be carried, otherwise the registration request of the UE will be rejected according to #100 (conditional IE error). After the UE side is first rejected for the reason value of #100, according to the protocol, the UE will wait for T3511 (in some examples, T3511 is set to 10s) and then try to register again. At this time, the MME has deleted the UE context due to the expiration of the timer, and the 5G AMF side cannot use the 4G MAP GUT I to find the UE context either, because although 5G has obtained the UE context from L, this context information is bound to the NGAP ID, and the life cycle of this NGAP ID is consistent with the link life cycle. After the UE re-establishes the link, the AMF can no longer obtain the UE context information taken from 4G. At this time, the AMF will reject the registration request of the UE according to #9 (UE identity cannot be derived by the network).

[0054] Based on the above-mentioned problematic scenario, the problem we need to solve is as follows: During the handover of the UE from LTE to NR, if the mobility registration triggered by the UE in the subsequent different system is not completed and the UE enters the IDLE state later, LTE may delete the UE context information in LTE due to the timeout of the timer. However, the 5G network cannot address the UE context information obtained from LTE by the 5G network based on the 4G MAPGUTI carried by the UE, resulting in the failure of the subsequent registration process.

[0055] Based on this, the embodiment of the present application provides a network handover method. In response to an exception occurring in the mobility registration when the terminal device hands over from the first network device to the second network device, and the terminal device enters the idle state, and the duration of the exception is within the first preset duration, a mobility registration request is sent to the second network device. The mobility registration request carries the first information, and the first information is used for the second network device to verify the terminal device through the first network device. When the duration of the exception exceeds the first preset duration, an initial registration request is sent to the second network device. In this way, when an exception occurs in the mobility registration of the terminal device, different registration requests can be sent to the second network device according to different time nodes, so as to avoid the problem that the registration request initiated again when the terminal device is in the idle state due to a link interruption causes a registration exception in the second network device, resulting in the terminal device being unable to successfully access the network device.

[0056] The following will specifically introduce the network handover method provided by the embodiment of the present application in conjunction with the accompanying drawings.

[0057] Please refer to Figure 2 , Figure 2 which shows a schematic diagram of the hardware structure of a terminal device or a network device. As Figure 2 shown, the terminal device or the network device may include a processor 201, a communication line 202, a memory 203, and at least one communication interface ( Figure 2 only an example of including the communication interface 204 is given here for illustration).

[0058] The processor 201 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present application solution, and is used to implement the network handover method described in any one of the embodiments of the present application.

[0059] The communication line 202 may include a path for transmitting information between the above components.

[0060] A communication interface 204, using any device such as a transceiver, for communicating with other devices or communication networks, such as Ethernet, RAN, WLAN, etc.

[0061] In the embodiments of the present application, the communication line 202 and the communication interface 204 can be used to support the transmission of service data corresponding to an operator or a service instance between network devices and other network devices (such as a first network device and a second network device), etc.

[0062] The memory 203 can be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory can exist independently and be connected to the processor through the communication line 202. The memory can also be integrated with the processor.

[0063] Among them, the memory 203 is used to store computer execution instructions for implementing the solution of the present application. Among them, the memory 203 can store instructions for implementing two modular functions: send instructions, receive instructions, and process instructions, and be controlled by the processor 201 for execution. The processor 201 is used to execute the computer execution instructions stored in the memory 203, so as to implement the method provided in the following embodiments of the present application. Figure 2 The memory 203 shown in the figure is only a schematic diagram, and the memory may also include other functional instructions. The present invention does not limit this.

[0064] Optionally, the computer execution instructions in the present application can also be referred to as application code, and the present application does not make specific limitations on this.

[0065] In a specific implementation, as an embodiment, the processor 201 may include one or more CPUs, such as Figure 2 CPU0 and CPU1 in

[0066] It should be noted that Figure 2Merely as an example of a terminal device or a network device, the specific structure of the terminal device or the network device is not limited. For example, the terminal device or the network device may further include other functional modules.

[0067] In some embodiments, the devices to which the embodiments of the present application are applied may include one or more of the following: a UE device, an access and mobility management function (AMF) network element, a 3GPP protocol LTE access network (mobility management entity, MME), a service management function (SMF) network element, and a packet data network gateway (PGW) network element. The terminal device may perform mobility registration between different network devices by using the method provided by the embodiments of the present application.

[0068] UE device: used to identify by itself the process of switching from 4G to 5G network. If the UE enters the IDLE state during the switching process, the UE can continue to perform mobility registration as a 4G to 5G mobility registration. When the UE is in the IDLE state, a mobility registration request can be constructed by means of reselection, or the UE can directly initiate an initial registration and re-negotiate with the network to create context information, so as to prevent the network element device from determining that there is an incorrect IE carried in the registration request, or the context information in the core network has been deleted, resulting in a registration exception for the UE's registration request, which lengthens the subsequent process of the UE accessing the network device.

[0069] Core network (network element) device: When identifying the mobility registration initiated during the inter-system handover when the UE initiates a registration, but at this time the UE re-initiates from the IDLE state and does not carry the EPS NAS MSG Container, the network does not directly reject the UE. Instead, it locally searches for the UE context information through the terminal identifier Globally Unique Temporary UE Identity (GUTI) information corresponding to the UE in the 4G MAP. When the UE context information is not found locally or in the network, the identity authentication process, the authentication process, and the security mode command process are reissued to recreate the UE context information, enabling the UE to access the core network device, and then the registration acceptance is issued.

[0070] In some embodiments, refer to Figure 3 which shows a schematic flowchart of a network switching method for a terminal device provided by the embodiments of the present application. As Figure 3 shown, the method may include:

[0071] S301: During the process of the terminal device switching from the first network device to the second network device, the link is released, the terminal device enters the idle state, and the mobility registration fails abnormally.

[0072] It should be noted that during the process of the terminal device switching from the first network device to the second network device, if the link is abnormally released and the terminal device enters the idle state from the connected state, a registration exception will occur at the second network device when the terminal device sends a registration request to the second network device again, which will in turn cause an abnormal mobility registration of the terminal device. There are many scenarios where the terminal device returns to the idle state. For example, when accessing the target cell, the access fails due to signal problems, or the wireless link is abnormally released due to poor signal during registration. There is no specific limitation here.

[0073] S302: The terminal device sends a mobility registration request to the second network device. The mobility registration request carries first information, and the first information is used to verify the terminal device.

[0074] In some embodiments, in response to the abnormal mobility registration when the terminal device switches from the first network device to the second network device, after the terminal device enters the idle state, it sends a mobility registration request to the second network device again. The mobility registration request carries first information, and the first information is used for the second network device to verify the terminal device through the first network device; during the process of the terminal device switching from the first network device to the second network device, when the link is interrupted and the terminal device enters the idle state, the terminal device can send a mobility registration request to the second network device. The mobility registration request carries first information, and the first information is used for the second network device to verify the terminal device through the first network device when the second network device receives the mobility registration request.

[0075] In some embodiments, the mobility registration request also carries the status information and the first identification information, where the status information is used to indicate the registration status of the terminal device in the first network device, and the first identification information is used to indicate the context information of the terminal device in the first network device.

[0076] It should be noted that in the mobility registration request sent by the terminal device, in addition to the status information and the first identification information, the above-mentioned first information is also included. The second network device can use the status information, the first identification information, and the first information to implement the mobility registration request sent by the terminal device in the idle state. In some examples, when the status information indicates that the terminal device is already registered with the first network device, the second network device determines that the terminal device sending the mobility registration request is from the first network device, and based on the first information, the second network device verifies the terminal device. After the verification passes, the second network device can obtain the context information of the terminal device in the first network device based on the first identification information, and complete the mobility registration request of the terminal device.

[0077] In some embodiments, the sending of the mobility registration request to the second network device may include: obtaining the tracking area update information of the terminal device, and encrypting and integrity protecting the tracking area update information according to the security context information configured by the terminal device and the first network device to obtain the first information; obtaining the mobility registration request based on the first information, the status information, and the first identification information of the terminal device, and sending it to the second network device.

[0078] It should be noted that when the terminal device is in the idle state, it can send a mobility registration request to the second network device. The mobility registration request includes the first information, the status information, and the first identification information. The first information may include the tracking area update information, and the tracking area update information can indicate to the second network device that the terminal device is from the first network device. The second network device can initiate the verification of the terminal device to the first network device based on the tracking area update information. After the verification passes, the second network device can obtain the context information of the terminal device from the first network device through the first identification information, and complete the mobility registration request of the terminal device.

[0079] In some embodiments, the tracking area update information (TAU) that has been sent to the first network device is encrypted and integrity protected using the security context information corresponding to the first network device, as well as the encryption algorithm and integrity protection algorithm configured by the first network device and the terminal device, and is sent to the second network device as the first information. The second network device sends the first information to the first network device, and the first network device then performs reverse integrity protection and decryption to see if it can be successfully parsed. If the parsing is successful, it is considered that the verification of the terminal device passes.

[0080] S303: When the verification of the terminal device is successful, the terminal device accesses the second network device.

[0081] In some embodiments, when the verification of the terminal device is successful, access the second network device. When the second network device receives a mobility registration request, the terminal device is verified through the first network device by using the first information carried in the mobility registration request. When it is determined that the terminal device comes from the first network device, the verification of the terminal device is passed and the terminal device accesses the second network.

[0082] In some embodiments, the tracking area update information (TAU) that has been sent to the first network device is encrypted and integrity protected by using the security context information corresponding to the first network device, as well as the encryption algorithm and integrity protection algorithm configured between the first network device and the terminal device, and is sent to the second network device as the first information. The second network device sends the first information to the first network device, and the first network device then performs reverse integrity protection and decryption to check whether it can be successfully parsed. If the parsing is successful, it is considered that the verification of the terminal device is passed.

[0083] In some embodiments, refer to Figure 4 , which shows a detailed flowchart of a network switching method for a terminal device provided by an embodiment of the present application. As Figure 4 shown, after the terminal device recognizes a network switching scenario, when performing mobility registration, if an exception occurs, it should not be regarded as a failure, and the timer T3511 maintained in the terminal device should not be started. That is to say, the terminal device does not need to wait for the duration of the timer T3511 and can immediately initiate a mobility registration request carrying the status information (UE Status) corresponding to the terminal device that needs to perform mobility registration and the EPS NAS MSG (IE item, that is, the first information in the foregoing embodiment). This registration process is equivalent to the UE being reselected from the IDLE state, and the UE initiates a reselection registration process. Because the core network of LTE may not have deleted the UE context at this time, when the 5G AMF (Access and Mobility Management Function) receives the UE registration request, the registration request can carry the 4G MAP GUT I (that is, the first identification information in the foregoing embodiment) to obtain the UE context from the LTE MME (Mobility Management Entity) node, which can prevent abnormal access to the second network device.

[0084] In some examples, the method may include:

[0085] S401: The MME sends a handover command to the 4G base station (eNB);

[0086] S402: The eNB sends a handover command of the E-UTRAN to the UE;

[0087] S403: The UE sends a handover confirmation to the 5G base station (gNB) to the 5G-RAN;

[0088] S404: The gNB sends a handover notification to the AMF;

[0089] S405: The AMF sends a reconfiguration complete notification to the gNB;

[0090] S406: The gNB sends a reconfiguration complete notification confirmation to the AMF;

[0091] S407: The UE in the connected state initiates a registration request, carrying UE-STATUS and not carrying IE items; In some examples, terminal identification information may be carried.

[0092] S408: In the foregoing S403 and S407, for example, due to poor link signal quality, a link interruption occurs, or the underlying layer indicates that cell access fails and the NAS needs to go back to the reconstruction process from the idle state, the network access server (NAS) needs to treat it as reselecting the UE from LTE, carry UE-STATUS, encrypt and protect the LTE TAU request with the LTE context information and carry it to the network through the IE item, and does not start the timer T3511 maintained in the UE to wait for it to time out, but immediately initiates a registration request attempt.

[0093] S409: The UE re-sends a registration request to the gNB from the idle state, carrying UE-STATUS and carrying IE items;

[0094] S410: The gNB sends the registration request to the AMF, carrying UE-STATUS and carrying IE items;

[0095] S411: The AMF re-obtains the UE context information from the MME through the identification information corresponding to the UE, and verifies the UE with the IE item;

[0096] S412: In the case where the UE verification passes, the context information corresponding to the UE is returned to the AMF;

[0097] S413: The AMF replies with a registration acceptance message to the gNB;

[0098] S414: The gNB sends the registration acceptance message to the UE.

[0099] It should be noted that the UE receives the handover command sent by the network and replies to the network handover confirmation message on 5G. The UE switches from LTE to NR, initiates a mobility registration, carries the UE status (i.e., the status information in the foregoing embodiment) as EMM-REGISTRED (registered), carries the terminal device identity Mobile Identity as 4G MAP GUTI (i.e., the first identification information in the foregoing embodiment), and does not carry the EPS NAS Message Container (IE item, i.e., the first information in the foregoing embodiment). In the S2.0 and S3.0 processes, for example, due to poor link signal quality, a link interruption occurs, or the underlying layer indicates that the cell access fails and the NAS (access server) needs to go through the Fallback reconstruction process from the IDLE state. At this time, the NAS needs to be regarded as reselecting the UE from LTE, carry the UE Status as EMM-REGISTRED, carry the 4G MAP GUTI, and use the LTE context to encrypt and integrity protect to construct an LTE TAU request and carry it to the network through the EPS NAS Message Container, without starting the timer T3511 in the UE to wait for it to time out, and immediately initiate a registration attempt. Because at this time, the MME may not have deleted the UE context yet, and the entire process can continue because it can also be retained. The AMF network sends a registration acceptance to the UE side.

[0100] In some examples, the IE item can be encrypted and integrity protected for the TAU on LTE using the LTE security context information, the encryption algorithm configured on LTE, the integrity protection algorithm, and the LTE uplink NAS counter, and then sent to the NR core network. The NR core network gives this EPS NAS message container to LTE, and the LTE network then performs reverse integrity protection and decryption to see if it can be successfully parsed. In the case of successful parsing, it is considered that the terminal device verification passes.

[0101] In some embodiments, refer to Figure 5 , which shows a schematic flow diagram of another network handover method for a terminal device provided by an embodiment of the present application. As Figure 5 shown, the method may further include:

[0102] In the case where the duration of the exception in the mobility registration does not exceed the preset duration, S302-S303 can be executed. The detailed process is the same as the description of Figure 3 in the foregoing embodiment and will not be elaborated here.

[0103] In the case where the duration of the exception in the mobility registration exceeds the preset duration, S304-S305 can be executed.

[0104] S304: Send an initial registration request to the second network device.

[0105] In some examples, when the duration of the abnormal mobility registration exceeds a first preset duration, an initial registration request is sent to the second network device; when the initial registration request is successful, access the second network device.

[0106] It should be noted that after the terminal device sends a mobility registration request to the second network device, when the time length of the abnormal mobility registration of the terminal device is greater than or equal to the first preset duration, it can be considered that the terminal device cannot access the second network device through the mobility registration request, and the terminal device can send an initial registration request to the second network device. In some examples, before the terminal device sends an initial registration request to the second network device, local deregistration needs to be performed, that is, the terminal device deletes the context information of the terminal device locally to achieve initial registration on the second network device.

[0107] In some embodiments, the terminal device maintains a first timer. After the mobility registration fails when the terminal device switches from the first network device to the second network device, the method may further include: when the first timer is in an overtime state, determining that the duration of the abnormal mobility registration exceeds the first preset duration. Based on this, the first timer in the terminal device can be started when the terminal device begins to switch from the first network device to the second network device. When the mobility handover of the terminal device fails, it is judged whether the first timer is in an overtime state. When the first timer does not time out, the terminal device can send a mobility registration request to the second network device according to the method in the foregoing embodiments. When the first timer times out, the terminal device can directly send an initial registration request to the second network device.

[0108] In some embodiments, the first timer is configured according to a second timer maintained in the first network device.

[0109] It should be noted that a second timer is maintained in the first network device. The second timer is used to delete the context information of the terminal device in the first network device after the second timer times out when the terminal device starts mobility registration. The first preset duration corresponding to the first timer can be configured according to the preset duration of the second timer. Exemplarily, the first timer can have the same preset duration as the second timer, or can be configured according to the preset durations of multiple second timers corresponding to multiple first network devices. Among them, the preset durations of the multiple second timers can be the same or different, so that when the first network device has not deleted the context information, the terminal device sends a mobility registration request, enabling the second network device to obtain the corresponding context information from the first network device, thereby saving the time and resources for establishing the context information. When the first network device has already deleted the context information, the terminal device directly sends an initial registration request to the second network device to re - establish the context information with the second network device, so as to ensure that the terminal device can successfully access the second network device.

[0110] S305: When the initial registration is successful, access the second network device.

[0111] In some embodiments, before the mobility registration fails in response to the terminal device switching from the first network device to the second network device, the method may further include: during the process of switching from the first network device to the second network device, sending a mobility registration request to the second network device, where the mobility registration request carries the status information and the first identification information of the terminal device.

[0112] It should be noted that when the terminal device is accessing the first network device and needs to switch from the first network device to the second network device, it needs to send a mobility registration request to the second network device. Among them, the mobility registration request carries the status information and the first identification information of the terminal device. The second network device can judge through the status information. Exemplarily, when the status information indicates that the terminal device is already registered in the first network device, the second network device determines that the terminal device sending the mobility registration request is from the first network device, and then obtains the context information of the terminal device in the first network device through the first identification information and completes the mobility registration request of the terminal device.

[0113] In some embodiments, refer to Figure 6 , which shows a detailed flowchart of another network switching method for a terminal device provided by an embodiment of the present application. As shown in Figure 6As shown, the UE sets a timer. If it occurs within a certain period of time after handover, the UE can directly initiate the process of reselecting from LTE to NR as a mobility registration, carrying the UE status and EPS NASMSG Container. Since the MME of LTE has not deleted the UE context at this time, the registration can succeed. When the time has passed when the UE initiates the registration attempt, the UE will initiate an initial registration to prevent registration anomalies on the network side.

[0114] In some examples, the method may include:

[0115] S601: The E-UTRAN network sends a handover command to the UE;

[0116] S602: The UE marks the handover scenario and starts the first timer T;

[0117] S603: The UE sends a mobility registration request to the NR network;

[0118] S604: The mobility registration causes the link to be released due to underlying reasons, or any anomaly occurs during the registration, causing the UE to enter the idle state;

[0119] Determine whether the first timer T has timed out through alt. The first timer T has not timed out

[0120] S605: The UE reselects from LTE to NR, and needs to use the security context of LTE to encrypt and protect the construction of TAU and carry the IE item to the network;

[0121] S606: The UE initiates a mobility registration between different systems, carrying UE-STATUS and carrying the IE item;

[0122] S607: The NR network sends a registration success message to the UE.

[0123] Determine whether the first timer T has timed out through alt. The first timer T has timed out

[0124] S608: The UE deregisters locally. In some examples, the UE can delete the context information of the terminal device and then immediately initiate an initial registration;

[0125] S609: The UE triggers an initial registration and sends an initial registration request to the NR network;

[0126] S610: The NR network sends a registration success message to the UE.

[0127] It should be noted that the UE actively and precisely identifies the optimization scenario. Before the network deletes our security context, the UE can initiate a mobility registration request in the manner of reselection to a different system, so that the UE can still register successfully. If the first timer has expired, the UE can only initiate local deregistration and then initial registration. In some examples, a timer is started inside the UE. Within a certain period of time after the handover command is sent, the UE immediately initiates a mobility registration request as if it has just reselected from LTE, carrying the UE Status as EMM-REGISTRED, carrying the 4G MAP GUTI, and encrypting and integrity-protecting the LTE TAU request with the LTE context and then carrying it to the network through the EPS NAS Message Container, without starting the UE timer T3511 and waiting for it to expire, but immediately initiating a registration attempt. Because at this time, the MME may still be about to delete the UE context, the entire registration process can still continue, because the UE context information can also be retained. If it is not within this time period, the UE follows the initial registration process.

[0128] In some examples, the IE item can use the LTE security context information, the encryption algorithm configured on LTE, the integrity protection algorithm, and the LTE uplink NAS counter on LTE to encrypt and integrity-protect the TAU and then send it to the NR core network. The NR core network gives this EPS NAS message container to LTE, and the LTE network then performs reverse integrity protection and decryption to see if it can be successfully parsed. In the case of successful parsing, it is considered that the terminal device passes the verification. In some embodiments, refer to Figure 7 , which shows a schematic flowchart of another method for a terminal device to switch networks provided by an embodiment of the present application, applied to a terminal device, such as Figure 7 shown, the method may include:

[0129] In response to an exception occurring in mobility registration when the terminal device switches from a first network device to a second network device, send an initial registration request to the second network device; when the initial registration request is successful, access the second network device. During the process of the terminal device switching from the first network device to the second network device, when the link is interrupted and the terminal device enters the idle state, the terminal device can directly send an initial registration request to the second network device to re-establish context information with the second network device, so as to achieve the purpose of the terminal device accessing the second network device.

[0130] In some embodiments, the identity information of the terminal device is carried in the initial registration request, and the identity information is used by the second network device to authenticate the terminal device. Based on this, when the terminal device sends an initial registration request to the second network device, the second network device can authenticate the identity information of the terminal device. After passing the authentication, the terminal device can negotiate further with the second network device to establish new context information to achieve the registration of the terminal device with the second network device.

[0131] In some examples, after the UE identifies the HO handover scenario and enters the IDLE state, it performs an initial registration. At this time, the UE directly deletes the UE context information according to the initial registration, and negotiates and creates the UE context information again on the 5G network to prevent the UE from having a registration exception on the network side.

[0132] In some examples, as Figure 7 shown, the method may include:

[0133] S701: The first network device sends a handover command to the terminal device;

[0134] S702: The terminal device marks the handover scenario;

[0135] S703: The terminal device sends a mobility registration request to the second network device;

[0136] S704: If the mobility registration causes the link to be released due to underlying reasons, or any exception occurs during the registration and the UE enters the idle state, the UE deregisters locally and then immediately performs an initial registration;

[0137] S705: The terminal device triggers an initial registration and sends an initial registration request to the second network device;

[0138] S706: The second network device sends a registration success message to the terminal device.

[0139] It should be noted that the network issues a handover command, and the UE marks that the current UE is in the handover process. The UE initiates a mobility registration request in response to the handover command. When the UE is in a state with poor link signal quality and the link is interrupted, causing the UE to enter the idle state, or the underlying layer indicates that the cell access fails and the NAS needs to go through the Fallback re-establishment process from the IDLE state, the UE can directly delete the UE context information locally, including the current GUTI information, security context information, etc. The UE initiates an initial registration to the second network device, carrying the registration type as initial registration for the network. The second network device sends a registration acceptance message to the UE.

[0140] In some embodiments, refer to Figure 8, which shows a schematic flow chart of a network switching method of a network device provided in an embodiment of the present application, applied to a second network device, such as Figure 8 As shown, the method may include:

[0141] S801: The second network device receives a registration request sent by the terminal device.

[0142] It should be noted that when the second network device receives a registration request sent by the terminal device, the information carried in different registration requests is different, and the types of registration requests are also different. Exemplarily, according to the information carried in the registration request, the registration request may be the mobility registration request in the foregoing embodiment, or the mobility registration request, or the initial registration request. After the second network device receives the registration request, it can obtain the information carried in the registration request.

[0143] S802: Obtain the context information corresponding to the terminal device according to the registration request.

[0144] It should be noted that the second network device can obtain the context information corresponding to the terminal device according to the information carried in the registration request. Among them, the information carried in the registration request may be different, and the method of obtaining the context information of the terminal device may also be different.

[0145] In some embodiments, the registration request includes the status information, the first identification information, and the first information of the terminal device. Obtaining the context information corresponding to the terminal device based on the registration request may include: when the status information indicates that the registration status of the terminal device in the first network device is registered, verifying the terminal device through the first information; when the verification is successful, obtaining the context information corresponding to the terminal device from the first network device based on the first identification information.

[0146] It should be noted that the registration request includes status information, first identification information, and first information. When the status information indicates that the terminal device is registered in the first network device, the verification information of the terminal device is sent to the first network device according to the tracking area update information carried in the first information. After the verification passes, the context information corresponding to the terminal device is obtained in the first network device through the first identification information.

[0147] It should also be noted that the registration request includes status information, first identification information, and first information. Then, it can be considered that the registration request is the mobility registration request in the foregoing embodiment, and it can be combined with any implementation manner in which the terminal device issues a mobility registration request in the foregoing embodiment to enable the terminal device to access the second network device through the mobility registration request, and no limitation is made here.

[0148] In some embodiments, during the process that the second network device verifies the terminal device through the first network device, the second network device may send the first information to the first network device. After the first network device finishes decryption protection, it checks whether the decryption process can be successfully parsed. If the parsing is successful, it is considered that the verification of the terminal device passes. It should be noted that the first information is obtained by encrypting and protecting the Tracking Area Update (TAU) information that has been sent to the first network device, using the security context information corresponding to the first network device, as well as the encryption algorithm and protection algorithm configured between the first network device and the terminal device.

[0149] In some embodiments, obtaining the context information corresponding to the terminal device based on the registration request may include: sending an identity query request, an authentication request, and a security mode command to the terminal device; and creating the context information corresponding to the terminal device when the terminal device responds to the identity query request, the authentication request, and the security mode command.

[0150] It should be noted that when the second network device cannot obtain the context information of the terminal device from the first network device according to the information carried in the registration request, the second network device may directly request the terminal device to re-establish the context information. In some examples, it may send an identity query request, an authentication request, and a security mode command to the terminal device. After the terminal device responds to the identity query request, the authentication request, and the security mode command respectively, the second network device obtains the context information corresponding to the terminal device. In some examples, that the second network device cannot obtain the context information of the terminal device from the first network device according to the information carried in the registration request may include that the terminal device is in the idle state, and the request message carries status information and first identification information but does not carry the first information, so that the second network device cannot verify the terminal device and thus cannot obtain the context information of the terminal device from the first network device.

[0151] In some examples, refer to Figure 9 which shows a detailed flowchart of a network switching method for a network device provided by an embodiment of the present application, as Figure 9As shown, after the network recognizes the UE handover, the UE returns to the IDLE state and sends a registration request using the ID user identifier. AUTH authorization is performed, and the SMC establishes a communication process to prevent abnormal registration. When the network detects that the registration process initiated by the UE carries the UE status as EMM-REGISTRED, indicating that the terminal device is registered in the 4G network but does not carry the EPS NASMessage Container IE item, the core network does not directly reject the UE. Instead, it re-sends the Identity authentication process, the authentication process, and the security Modem command process to recreate the UE context information and then sends a registration acceptance.

[0152] In some embodiments, the method may include:

[0153] S901: The E-UTRAN network sends a handover command to the UE;

[0154] S902: The UE initiates a mobility registration request to the NR network;

[0155] S903: The mobility registration causes the link to be released due to underlying reasons, or any abnormality occurs during the registration, resulting in the UE transitioning from the connected state to the idle state;

[0156] S904: The UE initiates a mobility registration request to the NR network from the idle state;

[0157] S905: After detecting that the registration after the handover process is not completed, the core network NR network initiates a registration in the idle state. If the UE carries a 4G identifier but does not carry the IE item, the core network does not forcefully check the binding relationship between the UE STATUS and the IE item at this time, nor directly send a rejection. Instead, it goes through the identity process to query the UE identity;

[0158] S906: The NR network sends an identity query request to the UE;

[0159] S907: The UE sends an identity response to the NR network;

[0160] S908: The NR network sends an authentication request to the UE;

[0161] S909: The UE sends an authentication response to the NR network;

[0162] S910: The NR network sends a security mode command to the UE;

[0163] S911: The UE sends a security mode completion to the NR network;

[0164] S912: The NR network sends a registration acceptance message to the UE;

[0165] S913: The UE sends a registration completion message to the NR network.

[0166] It should be noted that after the core network identifies that the UE needs to switch from 4G to 5G, the UE context information cannot be addressed during the mobility registration process initiated by the UE. The NR network can actively initiate an identity (ID), authority (AUTH), and security mode command (SMC) process to the UE to create the UE - corresponding context information. In some examples, after the handover, the core network NR network actively identifies that the subsequent registration is due to an abnormal handover, and the UE carries the UE Status as EMM - REGISTERED, carries the 4G MAP GUTI but does not carry the EPS NAS MSGContainer. Since the first information carried in the EPS NAS MSG Container cannot be given to the MME to verify the UE at this time, and the 5G core network cannot perform UE context addressing through the 4G MAP GUTI carried by the UE, the NR network can directly issue the ID, AUTH, and SMC processes to avoid abnormal UE registration requests in the NR network.

[0167] In some embodiments, the mobility registration request includes first identification information. Obtaining the context information corresponding to the terminal device based on the registration request may include: obtaining the context information corresponding to the terminal device from the stored information based on the first identification information. Based on this, the second network device can perform local addressing according to the first identification information to obtain the context information of the terminal device, where the association relationship between the first identification information and the context information is stored locally in the second network device.

[0168] In some embodiments, the method may further include: receiving the context information corresponding to the terminal device from the first network device; storing the association relationship between the first identification information and the context information in the second network device. Based on this, when the second network device receives the context information corresponding to the terminal device sent by the first network device, and when the overhead of the second network device permits, the second network device can store the association relationship between the first identification information and the context information in the second network device, so that when the terminal device mobility registration is abnormal and the context information of the terminal device cannot be obtained from the first network device, the context information of the terminal device can be obtained through local addressing in the second network device according to the first identification information.

[0169] In some embodiments, the context information corresponding to the terminal device is sent by the first network device to the second network device before the terminal device is switched from the first network device to the second network device. Based on this, the first network device can proactively send the context information of the terminal device to the second network device before network switching, so that the second network device can store the association relationship between the first identification information and the context information.

[0170] In some examples, refer to Figure 10 , which shows a detailed flowchart of another network switching method provided by an embodiment of the present application. As Figure 10 shown, the network adjustment addressing method adds support for 4G MAP GUTI. In the process of switching from 4G to 5G, after the 5G network obtains the UE context information from the 4G network, in addition to associating this context with the NGAP ID (next-generation communication identifier), the connected-state 5G also needs to additionally associate the 4G MAP GUTI with this UE context information. Subsequently, if the UE Status carried in the registration request initiated by the UE received by the 5G core network is EMM REGISTERED (indicating that this UE comes from the 4G network) and the 4G MAP GUTI address information, and the network fails to obtain the context information from the 4G core network, the 5G core network can search for the UE context locally through the 4G GUTI MAP to prevent abnormal mobility registration.

[0171] In some embodiments, the method may include:

[0172] S1001: When there is a need for mobility registration, the E-UTRAN network pre-sends a reconfiguration request to the NR network;

[0173] S1002: In addition to the current NGAP ID in the addressing method of the UE context in the NR network, the 4G identifier can be used as an address in the vicinity of the NR network to prevent the subsequent UE from initiating a mobility registration request in the idle state, but the NR network loses the NGAP ID and cannot obtain the UE context locally;

[0174] S1003: The NR network sends a reconfiguration response to the E-UTRAN network;

[0175] S1004: The E-UTRAN network sends a handover command to the UE;

[0176] S1005: The UE initiates a mobility registration request to the NR network;

[0177] S1006: In the case of abnormal registration of the UE, the link is released due to poor signal, or access failure causes the UE to need to re-establish a link from the idle state;

[0178] S1007: The UE sends a mobility registration request to the NR network in the idle state, carrying a 4G identifier, which can be the 4G MAP GUTI in the foregoing embodiments;

[0179] S1008: The AMF in the NR network adds a process of looking up the UE context locally using the 4G identifier;

[0180] S1009: When the UE context information is found, the NR network replies with a UE registration acceptance message.

[0181] It should be noted that this method can solve the problem that when the UE sends a mobility registration request to the core network of the NR network, when the AMF responds to the mobility self-registration request for normal handover, the base station sends uplink data to the AMF, and the UE initiates an initial context setup process in the IDLE state. The transmitted content is the same, but since the addressing identifier of the context that the AMF gets from the MME for the UE is the NGAP ID, which is bound to the lifecycle of the link, the NGAP ID becomes invalid after the link is interrupted, resulting in the AMF being unable to use the NGAP ID for addressing again. The core network can allocate resources and overhead by evaluating the AMF. In some examples, the overhead of 4G MAP GUTI addressing can be increased.

[0182] S803: Register the terminal device to the second network device based on the context information.

[0183] It should be noted that the terminal device is registered to the second network device based on the context information corresponding to the terminal device. This step is mainly used for establishing an association relationship between the second network device and the terminal device through the context information after the second network device obtains the context information of the terminal device, so as to realize the access of the terminal device to the second network device.

[0184] In some embodiments, after the terminal device is registered to the second network device, there is an association relationship between the context information corresponding to the terminal device and the second network device. Based on this, after the terminal device accesses the second network device, there is an association relationship between the context information corresponding to the terminal device and the second network device. In some examples, in the case where the second network device obtains the context information of the terminal device, an association relationship between the second identification information and the context information can be established, and a registration acceptance message is sent to the terminal device.

[0185] S804: The second network device sends a registration acceptance notification to the terminal device.

[0186] It should be understood that the various solutions of the embodiments of the present application can be reasonably combined and used, and the explanations or descriptions of the various terms appearing in the embodiments can be referred to or explained with each other in the various embodiments, which are not limited herein.

[0187] It should also be understood that in the various embodiments of the present application, the magnitudes of the serial numbers of the above processes do not mean the order of execution is prior or subsequent. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0188] It can be understood that in order for a network device (such as a first network device or a second network device) to implement the functions of any of the above embodiments, it includes the corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of the examples described in the embodiments disclosed herein, 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 form of hardware or computer software driving the hardware depends on the specific application and design constraint conditions of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0189] The embodiments of the present application can perform a functional module division on the network device. For example, each functional module can be divided corresponding to each function, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. It should be noted that the division of modules in the embodiments of the present application is illustrative, only a logical function division, and there can be other division methods in actual implementation.

[0190] It should also be understood that the various modules in the network device can be implemented in the form of software and / or hardware, which is not specifically limited herein. In other words, the network device is presented in the form of functional modules. Here, the "module" can refer to an application-specific integrated circuit ASIC, a circuit, a processor and a memory that execute one or more software or firmware programs, an integrated logic circuit, and / or other devices that can provide the above functions.

[0191] In an alternative approach, when data transmission is implemented using software, it can be realized in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are realized in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) means. 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 a data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a digital video disk (DVD)), or a semiconductor medium (such as a solid state disk (SSD)), etc.

[0192] The steps of the methods or algorithms described in connection with the embodiments of the present application may be implemented in hardware 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 (RAM), flash memory, read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), memory, register, hard disk, removable hard disk, compact disc read-only memory (CD-ROM), or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor such 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 an application specific integrated circuit (ASIC). Additionally, the ASIC may be located in a network device. Of course, the processor and the storage medium may also exist as discrete components.

[0193] From the description of the above embodiments, those skilled in the art can clearly understand that for the convenience and simplicity of description, only the above division of each functional module is used as an example. In actual applications, the above functions may be assigned to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

Claims

1. A network switching method, characterized in that, Applied to a terminal device, the method includes: In response to an abnormal mobility registration when the terminal device switches from a first network device to a second network device, after the terminal device enters the idle state, it sends a mobility registration request to the second network device again. The mobility registration request carries first information, and the first information is used for the second network device to verify the terminal device through the first network device; When the verification is successful, access the second network device.

2. The method according to claim 1, characterized in that, The method further includes: When the duration of the abnormal mobility registration exceeds a first preset duration, send an initial registration request to the second network device; When the initial registration request is successful, access the second network device.

3. The method according to claim 1 or 2, characterized in that, Before responding to an abnormal mobility registration when the terminal device switches from a first network device to a second network device, the method further includes: During the process of switching from the first network device to the second network device, send a mobility registration request to the second network device. The mobility registration request carries the status information and first identification information of the terminal device.

4. The method according to claim 1 or 3, characterized in that, The mobility registration request also carries the status information and the first identification information, where the status information is used to indicate the registration status of the terminal device in the first network device, and the first identification information is used to indicate the context information of the terminal device in the first network device.

5. The method according to claim 3, characterized in that, The sending of the mobility registration request to the second network device includes: Obtain the tracking area update information of the terminal device, and encrypt and integrity protect the tracking area update information according to the security context information configured by the terminal device and the first network device to obtain the first information; Based on the first information, the status information, and the first identification information of the terminal device, obtain the mobility registration request and send it to the second network device.

6. The method according to claim 2, characterized in that, The terminal device maintains a first timer. After responding to an abnormal mobility registration when the terminal device switches from a first network device to a second network device, the method further includes: When the first timer is in an overtime state, determine that the duration of the abnormal mobility registration exceeds the first preset duration.

7. The method according to claim 6, characterized in that, The first timer is configured according to a second timer maintained in the first network device.

8. A network switching method, characterized in that, Applied to a terminal device, the method includes: In response to an abnormal mobility registration when the terminal device switches from a first network device to a second network device, send an initial registration request to the second network device; When the initial registration request is successful, access the second network device.

9. The method according to claim 8, characterized in that, The initial registration request carries the identity information of the terminal device, and the identity information is used for the second network device to authenticate the terminal device.

10. A network switching method, characterized in that, Applied to a second network device, the method includes: Receive the registration request sent by the terminal device; Obtain the context information corresponding to the terminal device based on the registration request; Register the terminal device to the second network device based on the context information corresponding to the terminal device.

11. The method according to claim 10, characterized in that, After registering the terminal device to the second network device, the association relationship between the context information corresponding to the terminal device and the second identification information in the second network device.

12. The method according to claim 10 or 11, characterized in that, Obtaining the context information corresponding to the terminal device based on the registration request includes: Sending an identity query request, an authentication request, and a security mode command to the terminal device; Creating the context information corresponding to the terminal device when the terminal device responds to the identity query request, the authentication request, and the security mode command.

13. The method according to claim 10 or 11, characterized in that, The registration request includes the status information, the first identification information, and the first information of the terminal device. Obtaining the context information corresponding to the terminal device based on the registration request includes: When the status information indicates that the registration status of the terminal device with the first network device is registered, verifying the terminal device through the first information; When the verification is successful, obtaining the context information corresponding to the terminal device from the first network device based on the first identification information.

14. The method according to claim 10 or 11, wherein, The registration request includes the first identification information. Obtaining the context information corresponding to the terminal device based on the registration request includes: Obtaining the context information corresponding to the terminal device from the stored information based on the first identification information.

15. The method according to claim 14, wherein, The method further includes: Receiving the context information corresponding to the terminal device from the first network device; Storing the association relationship between the first identification information and the context information in the second network device.

16. The method according to claim 15, wherein, The context information corresponding to the terminal device is sent by the first network device to the second network device before the terminal device switches from the first network device to the second network device.

17. A terminal device, wherein, The terminal device includes: A transceiver for sending and receiving signals; A memory for storing computer program instructions; A processor for executing the computer program instructions to support the terminal device in implementing the method according to any one of claims 1-7 or 8-9.

18. A network device, wherein, The network device includes: A transceiver for sending and receiving signals; A memory for storing computer program instructions; A processor for executing the computer program instructions to support the network device in implementing the method according to any one of claims 10-16.

19. A communication system, wherein, The communication system includes a terminal device, a first network device, and a second network device. The communication system is used to implement the method according to any one of claims 1-7 or 8-9 or 10-16.

20. A computer-readable storage medium, wherein, Computer program instructions are stored on the computer-readable storage medium. When the computer program instructions are executed by the processing circuit, the method according to any one of claims 1-7 or 8-9 or 10-16 is implemented.

21. A computer program product containing instructions, wherein, When the computer program product runs on a computer, the computer is caused to execute the method according to any one of claims 1-7 or 8-9 or 10-16.

22. A chip system, wherein, The chip system includes a processing circuit and a storage medium, and computer program instructions are stored in the storage medium; when the computer program instructions are executed by the processing circuit, the method described in any one of claims 1-7 or 8-9 or 10-16 is implemented.

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