UE context information interaction method, network device, and storage medium

Abstract

Embodiments of the present application provide a UE context information interaction method, a network device, and a storage medium. The method is executed by a first network device, and comprises: receiving an RRC re-establishment request message or an RRC resume request message sent by a UE (110); upon determining that UE context information is not stored and cannot be obtained from a second network device having the UE context information stored therein, sending, to a core network device, a first indication message used to obtain the UE context information (120); receiving an NG handover request message sent by the core network device and comprising the UE context information (130); and on the basis of the UE context information in the NG handover request message, completing RRC re-establishment or RRC resumption between the first network device and the UE (140).

Description

UE context information exchange method, network device and storage medium

[0001] Cross-references to related applications

[0002] This application is based on and claims priority to Chinese Patent Application No. 2025101282520, filed on January 27, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a UE context information interaction method, network device, and storage medium. Background Technology

[0004] In 5G network technology, whether a terminal (User Equipment, UE) completes wireless communication with a cell via Radio Resource Control (RRC) RRC re-establishment or RRC resume, the network equipment (gNodeB, gNB) of the target cell to which the UE is accessing needs to pre-store the UE context information. Regardless of whether it's an RRC re-establishment or RRC resume process, if the gNB of the target cell does not store the UE context information, it needs to obtain it from the gNB that stores the UE context information through the XN interface (XN Application Protocol) between other gNBs.

[0005] However, in practical applications, it is difficult to ensure that the gNB that needs to obtain UE context information maintains an XN interface connection with the gNB that stores UE context information, and it is also difficult to ensure that the 5G core network control unit (Access and Mobility Management Function, AMF) connected to the two gNBs transmitting UE context information is the same. This results in a low success rate for gNBs to obtain UE context information during RRC re-establishment or RRC recovery, affecting the success rate of RRC re-establishment or RRC recovery, which in turn affects the rapid recovery of UE data services and the user's service experience. Summary of the Invention

[0006] This application provides a UE context information interaction method, a network device, and a storage medium.

[0007] In a first aspect, embodiments of this application provide a UE context information interaction method, applied to a first network device, the method comprising: receiving a Radio Resource Control (RRC) re-establishment request message or an RRC recovery request message sent by a UE;

[0008] If it is determined that the UE context information is not stored and cannot be obtained from the second network device that stores the UE context information, a first indication message for obtaining the UE context information is sent to the core network device; an NG handover request message is received from the core network device, wherein the NG handover request message includes the UE context information, the UE context information is obtained by the core network device from the second network device through a second indication message, the second indication message is generated by the core network device based on the first indication message; and based on the UE context information in the NG handover request message, RRC re-establishment or RRC recovery between the first network device and the UE is completed.

[0009] Secondly, embodiments of this application provide a UE context information interaction method applied to a second network device. The method includes: receiving a second indication message sent by a core network device, wherein the second indication message is generated by the core network device based on a first indication message sent by a first network device; the first indication message is used to obtain UE context information; the first indication message is sent by the first network device to the core network device after receiving a Radio Resource Control (RRC) re-establishment request message or an RRC recovery request message sent by the UE, and after determining that the UE context information is not stored and cannot be obtained from the second network device that stores the UE context information; determining the UE context information based on the second indication message, and sending the UE context information to the core network device, so that the core network device sends an NG handover request message including the UE context information to the first network device, thereby enabling the first network device to complete RRC re-establishment or RRC recovery with the UE based on the UE context information in the NG handover request message.

[0010] Thirdly, embodiments of this application provide a UE context information interaction method applied to a core network device. The method includes: receiving a first indication message for obtaining UE context information, wherein the first indication message is sent by a first network device when it is determined that the UE context information is not stored and cannot be obtained from a second network device that stores the UE context information; generating a second indication message based on the first indication message, and obtaining the UE context information from the second network device through the second indication message; generating an NG handover request message including the UE context information, and sending the NG handover request message to the first network device, so that the first network device completes RRC re-establishment or RRC recovery with the UE based on the UE context information in the NG handover request message.

[0011] Fourthly, embodiments of this application provide a network device, including: at least one first processor; at least one first memory for storing at least one program; and when at least one of the programs is executed by at least one of the first processors, it implements the UE context information interaction method described in the first or second aspect.

[0012] Fifthly, embodiments of this application provide a core network device, including: at least one second processor; at least one second memory for storing at least one program; at least one of the programs is run by at least one second processor to perform the UE context information interaction method described in the third aspect.

[0013] In a sixth aspect, embodiments of this application provide a computer-readable storage medium storing a processor-executable program, which, when executed by a processor, is used to implement the UE context information interaction method described in any one of the first to third aspects.

[0014] In a seventh aspect, embodiments of this application provide a computer program product, including a computer program or computer instructions, wherein the computer program or computer instructions are stored in a computer-readable storage medium, a processor of a network device reads the computer program or computer instructions from the computer-readable storage medium and executes the computer program or computer instructions, causing the network device to perform the UE context information interaction method described in either the first or second aspect; or, a processor of a core network device reads the computer program or computer instructions from the computer-readable storage medium and executes the computer program or computer instructions, causing the core network device to perform the UE context information interaction method described in the third aspect. Attached Figure Description

[0015] Figure 1 is a flowchart of an embodiment of a UE context information interaction method applied in a first network device according to an embodiment of this application;

[0016] Figure 2 is a flowchart of another UE context information interaction method embodiment provided in this application for a first network device;

[0017] Figure 3 is a flowchart of an embodiment of a UE context information interaction method applied to a second network device provided in this application;

[0018] Figure 4 is a flowchart of an embodiment of a UE context information interaction method applied in a core network device according to an embodiment of this application;

[0019] Figure 5 is a UE context information interaction diagram provided in an embodiment of this application when the XN interface does not exist;

[0020] Figure 6 is a UE context information interaction diagram provided in an embodiment of this application when the XN interface exists but there is cross-AMF between network devices;

[0021] Figure 7 is a schematic diagram of the structure of a network device provided in an embodiment of this application;

[0022] Figure 8 is a schematic diagram of the structure of a core network device provided in an embodiment of this application. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0024] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0025] In this application, the terms "furthermore," "exemplarily," or "optionally" are used as examples, illustrations, or descriptions and should not be construed as being more preferred or advantageous than other embodiments or designs. The use of terms such as "furthermore," "exemplarily," or "optionally" is intended to present the relevant concepts in a specific manner.

[0026] However, in practical applications, it is difficult to ensure that the network device that needs to obtain UE context information and the network device that stores UE context information maintain an XN interface connection, and it is also difficult to ensure that the core network connected to the two network devices that transmit UE context information is the same. This results in a low success rate for network devices to obtain UE context information during RRC re-establishment or RRC recovery, which affects the success rate of RRC re-establishment or RRC recovery, and consequently affects the rapid recovery of UE data services.

[0027] To improve the success rate of obtaining UE context information during RRC re-establishment or RRC recovery, and thus improve the success rate of RRC re-establishment or RRC recovery, this application provides a UE context information interaction method, a network device, a core network device, a computer-readable storage medium, and a computer program product. When the UE context information interaction method is applied to a first network device, the method may first receive a Radio Resource Control (RRC) re-establishment request message or an RRC recovery request message sent by the UE. Then, if it is determined that no UE context information is stored and the context information cannot be obtained from a second network device that stores the UE context information, a first indication message for obtaining the UE context information is sent to the core network device. Then, an NG handover request sent by the core network device is received, wherein the NG handover request includes UE context information, which is obtained by the core network device from the second network device through a second indication message. The second indication message is generated by the core network device based on the first indication message. Then, based on the UE context information in the NG handover request, the RRC re-establishment or RRC recovery between the first network device and the UE is completed. When the first network device receives an RRC re-establishment request or RRC recovery request, and if the first network device does not have UE context information and cannot obtain UE context information from the second device, it can send a first indication message to the core network device. This can instruct the core network device to send a second indication message to the second network device based on the first indication message to obtain the UE context information stored in the second network device. In this way, even if the acquisition of UE context information based on the XN interface fails, the core network device can still ensure that it can obtain UE context information. This reduces the impact of the failure to acquire UE context information based on the XN interface on the acquisition of UE context information, thereby improving the success rate of the first network device in obtaining UE context information from the second network device. This helps to improve the success rate of RRC re-establishment or RRC recovery, and thus improves the efficiency of rapid recovery of UE data services.

[0028] Referring to Figure 1, Figure 1 illustrates a flowchart of a UE context information interaction method provided by an embodiment of this application. The embodiment shown in Figure 1 is applied to a first network device, and the UE context information interaction method may include steps 110 to 140.

[0029] Step 110: Receive the Radio Resource Control (RRC) Re-establishment Request message or RRC Recovery Request message sent by the UE.

[0030] Step 120: If it is determined that there is no stored UE context information and the UE context information cannot be obtained from the second network device that stores the UE context information, a first indication message for obtaining the UE context information is sent to the core network device.

[0031] Step 130: Receive the NG handover request message sent by the core network device, wherein the NG handover request message includes UE context information, the UE context information is obtained by the core network device from the second network device through the second indication message, and the second indication message is generated by the core network device according to the first indication message.

[0032] Step 140: Based on the UE context information in the NG handover request message, complete the RRC re-establishment or RRC recovery between the first network device and the UE.

[0033] In one embodiment, the first network device refers to the network device (i.e., gNB) in the target cell where the UE is about to switch access, and which does not store UE context information. Specifically, for the RRC re-establishment request message, the first network device refers to the target cell to which the UE reselects after a radio link failure, which is neither the source cell nor the target cell to which the UE belongs. The RRC re-establishment request message is a request message from the UE to re-establish the RRC connection in the target cell after a radio link failure. For the RRC recovery request message, the first network device refers to the network device of the target cell to which the UE needs to switch from an inactive state to an active state to re-access, rather than the cell that puts the UE into an inactive state. Furthermore, the RRC recovery request message is a network device request message from the target cell to switch the UE from an inactive state to an active state and access the target cell.

[0034] In one embodiment, the inability of the first network device to obtain context information from the second network device that stores UE context information means that the first network device sends a request message to the second network device to obtain context information based on the XN interface, but cannot obtain a response message from the second network device carrying context information.

[0035] In one embodiment, sending a first indication message for obtaining UE context information to the core network device means that the first device sends the content originally intended for instructing the second network device to obtain UE context information to the core network device via the first indication message. The first indication message carries UeContext Cell NCGI information (i.e., the second cell global identifier mentioned below), where the second cell global identifier refers to the NR Cell Global Identifier (NCGI) information used to indicate the cell where the network device storing the UE context information is located.

[0036] In one embodiment, the second indication message sent by the core network device is used to obtain UE context information from the second network device. The second indication message is generated by the core network device based on the first indication message. Specifically, the core network device first routes to the second network device based on the second cell global identifier in the first indication message, then generates the second indication message based on the information carried in the first indication message, and finally sends the second indication message to the second network device so that the second network device can respond with the relevant operations for the UE context information based on the content of the second indication message. The UE context information stored in the second network device can be responded with through a request message carrying a specific reason value.

[0037] In one embodiment, the UE context information stored in the second network device can be carried in an NG handover request message sent by the second network device to the core network device. The NG handover request message sent by the second network device to the core network device may include identification information indicating the cell where the first network device resides (i.e., the first cell global identifier hereinafter referred to as the first cell global identifier) ​​and the UE context information. The first cell global identifier enables the core network device to route to the first network device, thereby allowing the first network device to receive the NG handover request message sent by the core network device and obtain the UE context information.

[0038] In one embodiment, the NG handover request message sent by the core network device refers to an NG handover request message generated by the core network device based on the UE context information replied by the second network device. The NG handover request message sent by the core network device may include a handover triggering reason value, which is the network device's reason value for retrieving the UE context. The reason value for retrieving the UE context carried in the NG handover request message is a specific response of the core network device to the first indication message sent by the first network device. This reason value enables the first network device to determine that the UE context information carried in the received NG handover request message corresponds to the first indication message, and to extract the UE context information from the NG handover request message, including bearer information, security information, etc.

[0039] In one embodiment, during the process of completing the RRC re-establishment or RRC recovery between the first network device and the UE based on the context information in the NG handover request message, specifically, an RRC re-establishment message or an RRC recovery message may be sent to the UE first based on the UE context information in the NG handover request message, and then an RRC re-establishment completion message or an RRC recovery completion message may be received from the UE to complete the RRC re-establishment or RRC recovery between the first network device and the UE.

[0040] In one embodiment, for the RRC re-establishment request message, sending the RRC re-establishment message to the UE based on the UE context information in the NG handover request message means that after the first network device obtains the UE context information from the NG handover request message, it first performs resource admission control on the UE based on the UE context information to allocate radio resources to the UE, and then sends the RRC re-establishment message to the UE.

[0041] In one embodiment, for the RRC recovery request message, sending the RRC recovery message to the UE based on the UE context information in the NG handover request message means that after the first network device obtains the UE context information from the NG handover request message, it first verifies the UE based on the context information. After successful verification, it performs resource control and radio resource allocation for the UE, and then sends the RRC recovery message to the UE.

[0042] Since the first network device cannot verify the UE using context information without it, it will re-establish the RRC connection through the RRC Setup procedure. In contrast, this embodiment uses the core network device to obtain the UE context information for the first network device. This ensures that the first network device can still obtain the UE context information even when it cannot obtain it through the XN interface. Based on the UE context information, the first network device can send an RRC re-establishment message or RRC recovery message to the UE and receive an RRC re-establishment completion message or RRC recovery completion message from the UE. This maintains the RRC re-establishment or RRC process with the UE, thus avoiding the establishment of a new RRC connection for the UE. This helps improve the success rate of RRC re-establishment or RRC recovery, thereby improving the UE's ability to quickly recover data services.

[0043] In one embodiment, the inability to obtain UE context information from a second network device that stores UE context information can be determined as follows: there is no XN interface between the first and second network devices. This lack of an XN interface can mean either there is no XN interface between the first and second network devices, or there is an XN interface between the first and second network devices but they are not connected to the same core network device.

[0044] In one embodiment, the inability to obtain UE context information from a second network device that stores UE context information can be determined as follows: receiving a UE context retrieval failure message sent by the second network device, wherein the UE context retrieval failure message is a response message from the second network device to a UE context retrieval request message sent by the first network device.

[0045] In one embodiment, an example of receiving a UE context retrieval failure message sent by a second network device is that the first network device sends a UE context retrieval request message to the second network device through the XN interface. When the second network device confirms that the first network device cannot obtain UE context information through the XN interface, the second network device sends a UE context retrieval failure message to the first network device through the XN interface. In this case, the UE context retrieval failure message through the XN interface is the aforementioned UE context retrieval failure message.

[0046] In one embodiment, receiving a UE context retrieval failure message from a second network device means that an XN interface exists between the first and second network devices. The first network device sends a UE context request message to the second network device through the XN interface and receives the UE context retrieval failure message. The UE context retrieval failure message includes a reason value of "InterAMF triggered." Based on this reason value, the first network device can determine that the UE context failure is caused by itself and the second network device being connected to different AMFs. Therefore, it sends a first indication message to the core network device through the NG interface to obtain UE context information from the second network device. Specifically, since each core network independently manages the UE context information of its connected network devices, when the second network device stores the UE context information and has an XN interface with the first network device, if the first network device and the second network device are connected to the same core network device, then when the first network device sends a first indication message to the second network device, the second network device will send a successful response message to the first network device regarding the failure to retrieve the UE context, carrying the UE context information. Conversely, if the first network device and the second network device are connected to different core network devices, then the second network device will reply to the first network device with a failure to retrieve the UE context message in response to the first network device's request to obtain the UE context, carrying the reason value "InterAMF triggered" to indicate that even though the XN interface connection exists, the UE context information cannot be obtained.

[0047] Referring to Figure 2, which illustrates the flow of another embodiment of the UE context information interaction method applied to the first network device, in one embodiment, after step 140, steps 210 to 230 may be included.

[0048] Step 210: Send a handover confirmation message for NG to the core network equipment.

[0049] Step 220: Receive the downlink radio access network state transition message sent by the core network device. The downlink radio access network state transition message is generated by the core network device based on the packet data sequence number transmission information of the UE sent by the second network device. The downlink radio access network state transition message includes packet data sequence number transmission information, which is obtained by the second network device based on the NG handover command message sent by the core network device. The NG handover command message is generated by the core network device based on the NG handover confirmation message.

[0050] Step 230: Based on the packet data sequence number transmission information in the downlink radio access network state transition message, complete the data backhaul and send an NG handover notification message to the core network equipment to notify the core network equipment to perform downlink data path handover operation.

[0051] In one embodiment, the NG handover request acknowledgement message is a message sent by the first network device after completing RRC re-establishment or RRC recovery to confirm that it has successfully received and is ready to process the NG handover request from the second network device. Processing the NG handover request message from the second network device refers to the first network device activating the Data Radio Bearer (DRB) and performing data backhaul operations on the data that the second network device has not yet completed transmitting to the UE.

[0052] In one embodiment, the second network device obtaining packet data sequence number transmission information based on the NG handover command message sent by the core network device refers to the operation of the second network device generating packet data sequence number transmission information after receiving the NG handover command message. Here, packet data sequence number transmission information refers to sequence number transmission (SN transfer) information based on the Packet Data Convergence Protocol (PDCP).

[0053] In one embodiment, the core network device generates a downlink RAN ​​status transfer message based on the packet data sequence number transmission information of the UE sent by the second network device. This refers to the operation whereby the core network device first extracts the packet data sequence number transmission information carried in the received uplink RAN ​​status transfer message, and then generates the downlink RAN ​​status transfer message based on the packet data sequence number transmission information. The uplink RAN ​​status transfer message is generated by the second network device based on the packet data sequence number transmission information.

[0054] In one embodiment, the process of completing data backhaul based on the packet data sequence number transmission information in the downlink radio access network state transition message and sending an NG handover notification message to the core network device to notify the core network device to perform a downlink data path handover operation refers to the first network device determining the range of data packets that the second network device has not yet completed transmitting to the UE based on the packet data sequence number transmission information, then acquiring these data packets, sorting them according to the packet data sequence number transmission information, and sending an NG handover notification message to the core network device to notify the core network device that the corresponding UE has completed the UE handover access, thereby enabling the core network device to switch the UE from the second network device to the first network device.

[0055] Between the first network device, the second network device, and the core network device, since the core network device ensures that the first network device can obtain the UE context information stored in the second network device, the first network device can complete the radio resource admission control and security authentication of the UE during the RRC re-establishment or RRC recovery process. This enables it to send NG handover confirmation messages to the core network device and receive downlink radio access network state transition messages sent by the core network device, thereby quickly restoring the UE's data services and helping to ensure the continuity of data services to the UE.

[0056] In one embodiment, during the data radio bearer activation process between the first network device and the UE, specifically in the UE context information interaction method, the first network device may first send an RRC Reconfiguration message to the UE and receive an RRC Reconfiguration Complete message from the UE to complete the UE's radio bearer activation operation. The RRC Reconfiguration Complete message is sent by the UE after completing the reconfiguration based on the RRC Reconfiguration message. The RRC Reconfiguration message may include DRB configuration parameters, security parameters, Signaling Radio Bearer 2 (SRB2) parameters, etc., which are not specifically limited here.

[0057] By performing data backhaul, the first network device can restore the continuity of the UE's data services when it receives an NG handover request message carrying UE context information, thereby improving the UE's data service perception and experience.

[0058] Referring to Figure 3, which illustrates the flow of another UE context information interaction method provided by an embodiment of this application, the embodiment shown in Figure 3 is applied to the second network device mentioned in Figure 1, relative to the UE context information interaction method shown in Figure 1. The UE context information interaction method in Figure 3 may include steps 310 to 320.

[0059] Step 310: Receive a second indication message sent by the core network device, wherein the second indication message is generated by the core network device based on the first indication message sent by the first network device; the first indication message is used to obtain UE context information; the first indication message is sent by the first network device to the core network device after receiving a Radio Resource Control (RRC) Re-establishment Request message or an RRC Recovery Request message sent by the UE, and after determining that there is no stored UE context information and that the UE context information cannot be obtained from the second network device that stores the UE context information.

[0060] Step 320: Determine the UE context information according to the second instruction message, and send the UE context information to the core network device, so that the core network device sends an NG handover request message including the UE context information to the first network device, thereby enabling the first network device to complete the RRC re-establishment or RRC recovery with the UE according to the UE context information in the NG handover request message.

[0061] In one embodiment, in the second network device, the first network device cannot obtain the UE context information from the second network device that stores the UE context information in any of the following situations: the second network device cannot receive the first indication message for obtaining the UE context information through the XN interface between the second network device and the first network device; the second network device can receive the first indication message through the XN interface between the second network device and the first network device, but cannot respond to the first network device with the required UE context information through the XN interface.

[0062] In one embodiment, determining UE context information according to the second instruction message and sending the UE context information to the core network device means that the second network device determines the required UE context information that the first network device needs to obtain and the target cell (i.e., the cell where the first network device is located) according to the second instruction message, and then sends an NG handover request message carrying the required UE context information to the core network device.

[0063] After receiving an RRC re-establishment request message or an RRC recovery request message, if the first network device does not have UE context information and cannot obtain UE context information from the second device, it can receive a first indication message from the core network device. The core network device can then return its stored UE context information to the first network device. This ensures that even if obtaining UE context information via the XN interface fails, the core network device can still return the UE context information to the first network device. This reduces the impact of failures in obtaining UE context information via the XN interface, thereby increasing the success rate of the first network device obtaining UE context information from the second network device. This contributes to improving the success rate of RRC re-establishment or RRC recovery, ultimately improving the efficiency of rapid data service recovery for the UE.

[0064] In one embodiment, the second indication message may include a UE context information identifier. Specifically, during the process of determining the UE context information based on the second indication message, the UE context information can be determined based on the UE context information identifier in the second indication message. The UE context information identifier refers to information used to identify the UE context information corresponding to the UE. This UE context information identifier may be carried in an RRC re-establishment request message or an RRC recovery request message, etc., and is not specifically limited here. By using the UE context information identifier, the UE context information can be accurately determined, ensuring that the UE context information returned to the core network device can completely match the UE's verification information. This enables the first network device to complete the RRC re-establishment or RRC recovery with the UE, thereby improving the recovery efficiency of the UE's data services.

[0065] In one embodiment, the second indication message may further include integrity protection information for the UE context information and the first cell global identifier of the first network device. In the process of sending the UE context information to the core network device, the UE context information may be verified first according to the integrity protection information. When the verification is successful, an NG handover request message including the first cell global identifier and the UE context information is generated, and then the NG handover request message is sent to the core network device.

[0066] By including the integrity protection information for UE context information in the second instruction message, the integrity of the UE context information indicated by the UE context information identifier in the second network device can be verified. This allows the core network device to return accurate and complete UE context information, enabling the first network device to obtain accurate and complete UE context information for RRC re-establishment or RRC recovery with the UE, thereby improving the success rate of RRC re-establishment or RRC recovery.

[0067] In one embodiment, the NG handover request message may further include retrieving the UE context reason value. Specifically, during the process of sending the NG handover request message to the core network device, the core network device may send the NG handover request message to the core network device so that the core network device can cooperate with the second network device to perform NG handover based on the first cell global identifier according to the retrieved UE context reason value in the NG handover request message. In this case, the second network device does not send the handover command RRC reconfiguration message to the UE during the NG handover process.

[0068] Specifically, during the generation of the NG handover request message, a UE context reason value is added to the NG handover request message. The UE context reason value carried in the NG handover request message is a specific response to the second indication message sent by the core network device. Specifically, it enables the core network device to determine that the reason for the second network device to initiate the NG handover request message is to retrieve and return the UE context information required by the first network device. The core network device then generates and sends an NG handover request message carrying the UE context reason value and UE context information to the first network device based on the NG handover request message, in order to return the UE context information to the first network device.

[0069] In one embodiment, before receiving the second indication message sent by the core network device, the second network device, during the UE context information interaction method, may first receive a UE context request message sent by the first network device. This UE context request message is used to request UE context information. Then, it determines whether it is connected to the same core network as the first network device. If it is determined that it is not connected to the same core network as the first network device, it sends a UE context retrieval failure message to the first network device. This UE context retrieval failure message triggers the first network device to send a first indication message to the core network device. The UE context retrieval failure message carries the UE context retrieval failure reason value "InterAMF triggered". In this way, the second network device can instruct the first network device to determine that the UE context retrieval failure is caused by itself and the second network device being connected to different core networks. This allows the first network device to initiate a process of retrieving the UE context through the NG interface to the AMF, thereby enabling it to indirectly send UE context information to the first network device through the NG handover request message. In addition, when the first network device and the second network device are connected to the same core network, the first network device and the second network device can be connected to the same core network device under the core network, or they can be connected to different core network devices under the core network. No specific limitation is made here.

[0070] In one embodiment, the UE context request message obtained through the XN interface can be generated in the first network device in the following manner: first, UE context identification information is obtained, and then, the UE context request message is generated based on the UE context identification information.

[0071] In one embodiment, when it is determined that the second network device is connected to the same core network as the first network device, the second network device can determine the UE context information according to the UE context request message and return the UE context information to the first network device from the XN interface.

[0072] By determining whether the UE context information is managed by the same core network as the first network device, it can be determined whether the UE context information is connected to the same core network. In the case where they are not in the same core network, the core network device can return the UE context information to the first network device. In the case where they are in the same core network, the connected XN interface can be used to directly return the UE context information to the first network device. This allows the first network device to obtain the UE context information regardless of whether it is connected to the same core network as the second network device, thereby helping to improve the success rate of UE RRC re-establishment or RRC recovery.

[0073] In one embodiment, after the first network device completes the RRC re-establishment or RRC recovery of the UE, the second network device, when executing the UE context information interaction method, may first receive an NG handover command message sent by the core network device. The NG handover command message is generated by the core network device based on the NG handover confirmation message sent by the first network device in response to the NG handover request message. Then, the core network device obtains the UE's packet data sequence number transmission information based on the NG handover command message, generates an uplink radio access network state transition message including the packet data sequence number transmission information, and sends the uplink radio access network state transition message to the core network device. This enables the core network device to generate and send a downlink radio access network state transition message to the first network device based on the packet data sequence number transmission information in the uplink radio access network state transition message, thereby enabling the first network device to complete data backhaul based on the downlink radio access network state transition message.

[0074] In one embodiment, the core network device generates an NG handover command message based on the NG handover request confirmation message sent by the first network device. This means that after receiving the NG handover confirmation message, the core network device determines that the first network device has completed the network device handover preparation process and sends the NG handover command message to the second network device. After receiving the NG handover command message, the second network device does not send a handover command to the UE based on the reason value for retrieving the UE context in the previously sent NG handover request message.

[0075] In one embodiment, during the process of obtaining the packet data sequence number transmission information of the UE according to the NG handover command, the second network device can obtain the packet data sequence number transmission information by querying the sequence number of the sent data packets, or by reporting the packet data aggregation protocol sequence number (PDCP SN) fed back by the UE to the first network device, etc., and the specific details are not limited here.

[0076] By cooperating with the first network device to perform data backhaul, the first network device can restore the continuity of the UE's data services when it receives an NG handover request message carrying UE context information, thereby improving the UE's data service perception and experience.

[0077] Referring to Figure 4, which illustrates the flow of another UE context information interaction method provided by an embodiment of this application, the embodiment shown in Figure 4 is applied to the core network device mentioned in Figure 1, relative to the UE context information interaction methods shown in Figures 1 and 3. The UE context information interaction method in Figure 4 may include steps 410 to 430.

[0078] Step 410: Receive a first indication message for obtaining UE context information. The first indication message is sent by the first network device when it determines that it does not store UE context information and cannot obtain UE context information from the second network device that stores UE context information.

[0079] Step 420: Generate a second indication message based on the first indication message, and obtain UE context information from the second network device through the second indication message.

[0080] Step 430: Generate an NG handover request message including UE context information and send the NG handover request message to the first network device so that the first network device can complete the RRC re-establishment or RRC recovery with the UE based on the UE context information in the NG handover request message.

[0081] In one embodiment, obtaining UE context information from a second network device via a second indication message refers to the core network device sending a second indication message to the second network device, enabling the second network device to determine the UE context information based on the second indication message, and then receiving the UE context information returned by the second network device in a certain manner. The certain manner in which the UE context information is returned can be carried in the handover request message based on the first cell global identifier, as mentioned above.

[0082] In one embodiment, generating an NG handover request message including UE context information and sending the NG handover request message to the first network device means that the core network device first routes to the first network device according to the first cell global identifier of the first network device, then generates an NG handover request message carrying UE context information, and then sends the NG handover request message to the first network device according to the routing path to the first network device.

[0083] When the first network device lacks UE context information and cannot obtain it from the second device, the core network device can send a second indication message between the first and second network devices based on the first indication message sent by the first network device to obtain the UE context information stored in the second network device. In this way, even if the acquisition of UE context information based on the XN interface fails, the core network device can still enable the first network device to obtain the UE context information, thereby reducing the impact of the failure to acquire UE context information based on the XN interface on the acquisition of UE context information. This can improve the success rate of the first network device in obtaining UE context information from the second network device, which helps to improve the success rate of RRC re-establishment or RRC recovery, and thus improves the efficiency of rapid recovery of UE data services.

[0084] In one embodiment, the first indication message may include a second cell global identifier of the second network device, and the second indication message may include a UE context information identifier. During the process of obtaining UE context information from the second network device via the second indication message, the core network device may first determine a routing path to the second network device based on the second cell global identifier. Then, it sends the second indication message to the second network device via the routing path, enabling the second network device to determine the UE context information based on the UE context information identifier in the second indication message. Finally, it receives the UE context information sent by the second network device. The second cell global identifier allows for accurate routing to the second network device, ensuring that the second indication message is accurately sent to the second network device. This ensures that the second network device can perform operations such as querying and returning UE context information, and consequently, enables the second network device to correctly send NG handover request messages to return UE context information to the core network device.

[0085] In one embodiment, after the first network device completes RRC re-establishment or RRC recovery with the UE, when the core network device executes the UE context information interaction method, it can first receive an NG handover confirmation message sent by the first network device in response to the NG handover request message. Then, it obtains the UE's packet data sequence number transmission information from the second network device according to the NG handover confirmation message. Next, it generates a downlink radio access network state transition message including the packet data sequence number transmission information and sends the downlink radio access network state transition message to the first network device. Then, it receives an NG handover notification message sent by the first network device. The NG handover notification message is sent by the first network device after completing data backhaul according to the packet data sequence number transmission information in the downlink radio access network state transition message. Finally, it performs a downlink data path handover operation according to the NG handover notification message.

[0086] By cooperating with the first network device to perform data backhaul, the first network device can restore the continuity of the UE's data services when it receives an NG handover request message carrying UE context information, thereby improving the UE's data service perception and experience.

[0087] In one embodiment, during the process of obtaining the UE's packet data sequence number transmission information from the second network device based on the NG handover request response information, the core network device may first generate an NG handover command message based on the NG handover confirmation message and send the NG handover command message to the second network device, so that the second network device can obtain the UE's packet data sequence number transmission information based on the NG handover command message, and then receive the packet data sequence number transmission information sent by the second network device.

[0088] The following example illustrates the information exchange between the four devices when the XN interface is not present.

[0089] Referring to Figure 5, Figure 5 illustrates the information interaction between the terminal (UE in Figure 5), the first network device (target gNB1 in Figure 5), the second network device (gNB2 in Figure 5), and the core network device (AMF in Figure 5). At the beginning of the embodiment, the UE sends an RRC re-establishment request message or an RRC recovery request message to the first network device. After receiving the RRC re-establishment request message or the RRC recovery request message, the first network device first determines whether it has stored the UE context information. If it does, it directly completes the RRC re-establishment process or the RRC recovery process with the UE. If not, it checks whether there is an XN interface and related information between itself and the second network device. If not, it can first generate a first indication message for obtaining the UE context information based on the second cell global identifier of the second network device and the UE context information identifier, and then send the first indication message to the core network device through the NG interface between itself and the core network device. After receiving the first indication message, the core network device first determines the routing path from itself to the second network device based on the second cell global identifier. Then, it generates integrity protection information for the UE context information. Next, it generates a second indication message based on the first cell global identifier of the first network device, the UE context information identifier, and the integrity protection information. Then, it sends the second indication message to the second network device through the NG interface between the core network device and the second network device and the routing path to the second network device. After receiving the second instruction message, the second network device first determines the UE context information that the first network device needs to obtain based on the UE context information identifier. Then, it verifies the UE context information based on the integrity protection information. When the verification is successful, it generates an NG handover request message based on the first cell global identifier in the second instruction message and the UE context information, and makes the NG handover request message carry the UE context retrieval reason value. Then, it sends the NG handover request message to the core network device through the NG interface with the core network device. After receiving the NG handover request message, the core network device first determines the routing path from itself to the first network device based on the first cell global identifier. Then, it determines the reason why the second network device initiated the NG handover request message based on the UE context retrieval reason value, so that it can retrieve the UE context information from the NG handover request message. Then, based on the first cell global identifier carried in the NG handover request message, it sends the NG handover request message to the first network device through the routing path to the first network device and the NG interface with the first network device.Upon receiving the NG handover request message, the first network device first determines whether the NG handover request message carries UE context information based on the UE context retrieval reason value in the NG handover request message. It then matches the required UE context information from the NG handover request message and completes RRC re-establishment or RRC recovery with the UE based on the UE context information. When the UE confirms the completion of RRC re-establishment or RRC recovery with the first network device, it replies with an RRC re-establishment completion message or an RRC recovery completion message to the first network device. After receiving the RRC re-establishment completion message or RRC recovery completion message from the UE, the first network device sends an NG handover confirmation message to the core network device through the NG interface to initiate the handover operation. Simultaneously, the first network device also sends an RRC reconfiguration message to the UE. Upon receiving the RRC reconfiguration message, the UE performs radio bearer activation based on the RRC reconfiguration message. Meanwhile, upon receiving the NG handover confirmation message, the core network device generates an NG handover command message based on the NG handover confirmation message and then sends the NG handover command message to the second network device through the NG interface with the second network device. Upon receiving the NG handover command message, the second network device does not send an RRC reconfiguration message with a handover command to the UE. Instead, it first obtains the UE's packet data sequence number transmission information from the NG handover command message. Then, it generates an uplink radio access network state transition message based on the packet data sequence number transmission information and sends it to the core network device through the NG interface with the core network device. After receiving the uplink radio access network state transition message, the core network device extracts the packet data sequence number transmission information from it. Then, it generates a downlink radio access network state transition message based on the packet data sequence number transmission information and sends it to the first network device through the NG interface with the first network device for data backhaul. Upon receiving the downlink radio access network state transition message, the first network device completes the data backhaul and waits for the UE's response. When it receives the RRC reconfiguration complete message from the UE, it generates an NG handover notification message and sends it to the core network device to enable the core network device to perform downlink data path switching.

[0090] The following example illustrates the information exchange between the four devices when the XN interface exists but the first and second network devices are connected to different core networks.

[0091] Referring to Figure 6, Figure 6 illustrates the information interaction between the UE (UE in Figure 6), the first network device (target gNB1 in Figure 6), the second network device (gNB2 in Figure 6), and the core network device (AMF in Figure 6). At the beginning of the embodiment, the UE sends an RRC re-establishment or RRC recovery request to the first network device. After receiving the RRC re-establishment or RRC recovery request, the first network device first determines whether it has stored the UE context information. If not, it checks whether there is an XN interface and related information between itself and the second network device. If so, it first generates a UE context retrieval request message based on the UE context information identifier. This UE context retrieval request message is sent to the second network device through the XN interface to determine whether the UE context information can be obtained. After receiving the UE context retrieval request message, the second network device determines whether the first network device and itself are connected to the same core network. If they are the same, it returns the corresponding UE context to the first network device based on the context information identifier. If they are different, it generates a UE context retrieval failure message with the cause value "InterAMF triggered" and sends it to the first network device. The first network device determines, based on the reason value "InterAMF triggered" in the UE context retrieval failure message, that the failure to retrieve the UE context was caused by its own connection to a different core network than that of the second network device. Based on this, it generates a first indication message for obtaining the UE context information using the second network device's second cell global identifier and the UE context information identifier. Then, it sends the first indication message to the core network device via the NG interface with the core network device. Upon receiving the first indication message, the core network device first determines its routing path to the second network device based on the second cell global identifier. Next, it generates integrity protection information for the UE context information. Then, it generates a second indication message based on the first network device's first cell global identifier, the UE context information identifier, and the integrity protection information. Finally, it sends the second indication message to the second network device via the NG interface with the core network device and the routing path to the second network device.After receiving the second instruction message, the second network device first determines the UE context information that the first network device needs to obtain based on the UE context information identifier. Then, it verifies the UE context information based on the integrity protection information. If the verification fails, it can send a response indicating failure to obtain UE context information to the core network device, so that the core network device sends a response indicating failure to obtain UE context information to the first network device. If the verification is successful, it generates an NG handover request message based on the first cell global identifier in the second instruction message and the UE context information, and makes the NG handover request message carry the reason value for retrieving UE context. Then, it sends the NG handover request message to the core network device through the NG interface with the core network device. During this process, the second network device does not send a handover command message to the UE. After receiving an NG handover request message, the core network device first determines its routing path to the first network device based on the first cell global identifier. Then, based on the retrieved UE context reason value, it determines that the second network device initiated the NG handover request message to retrieve and return the UE context information required by the first network device, allowing it to extract the UE context information from the NG handover request message. Next, it generates an NG handover request message carrying the UE context information and the retrieved UE context reason value, and sends the NG handover request message to the first network device through the routing path to the first network device and the NG interface between the core network device and the first network device. Upon receiving the NG handover request message, the first network device first determines that the NG handover request message contains UE context information based on the retrieved UE context reason value in the NG handover request message, matching the UE context information from the NG handover request. Then, it completes RRC re-establishment or RRC recovery with the UE based on the UE context information. When the UE determines that it has completed RRC re-establishment or RRC recovery with the first network device, it replies with an RRC re-establishment completion message or an RRC recovery completion message to the first network device. After receiving an RRC re-establishment message or an RRC recovery completion message from the UE, the first network device sends an NG handover confirmation message to the core network device via the NG interface to initiate a handover operation. Simultaneously, the first network device also sends an RRC reconfiguration message to the UE. Upon receiving the RRC reconfiguration message, the UE performs radio bearer activation based on the RRC reconfiguration message. Meanwhile, upon receiving the NG handover confirmation message, the core network device first obtains the packet data sequence number transmission information based on the NG handover confirmation message, then generates an NG handover command message based on the packet data sequence number transmission information, and finally sends the NG handover command message to the second network device via the NG interface with the second network device.Upon receiving the NG handover command message, the second network device does not send an RRC reconfiguration message with the handover command to the UE. Instead, it first obtains the UE's packet data sequence number transmission information from the NG handover command. Then, it generates an uplink radio access network state transition message based on the packet data sequence number transmission information and sends it to the core network device through the NG interface with the core network device. After receiving the uplink radio access network state transition message, the core network device extracts the packet data sequence number transmission information from it. Then, it generates a downlink radio access network state transition message based on the packet data sequence number transmission information and sends it to the first network device through the NG interface with the first network device for data backhaul. Upon receiving the downlink radio access network state transition message, the first network device completes the data backhaul and waits for the UE's response. When it receives the RRC reconfiguration complete message from the UE, it generates an NG handover notification message and sends it to the core network device to enable the core network device to perform downlink data path switching.

[0092] Referring to Figure 7, which is a schematic diagram of the structure of a network device according to an embodiment of this application, the network device includes a first memory 1100 and a first processor 1200. The number of the first memory 1100 and the first processor 1200 can be one or more; Figure 7 shows an example of one first memory 1100 and one first processor 1200. The first memory 1100 and the first processor 1200 in Figure 7 can be connected via a bus or other means; Figure 7 shows an example of connection via a bus.

[0093] The first memory 1100, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules, such as the program instructions / modules corresponding to the UE context information interaction method executed in the first network device or the second network device provided in any embodiment of this application. The first processor 1200 implements the aforementioned UE context information interaction method executed in the first network device or the second network device by running the software programs, instructions, and modules stored in the first memory 1100.

[0094] The first memory 1100 may primarily include a first stored program area and a first stored data area, wherein the first stored program area may store the operating system and application programs required for at least one function. Furthermore, the first memory 1100 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some instances, the first memory 1100 may further include memory remotely located relative to the first processor 1200, and these remote memories may be connected to the device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0095] Referring to Figure 8, which is a schematic diagram of the structure of a core network device according to an embodiment of this application, the network device includes a second memory 1300 and a second processor 1400. The number of second memories 1300 and second processors 1400 can be one or more; Figure 8 shows an example of one second memory 1300 and one second processor 1400. The second memory 1300 and the second processor 1400 in Figure 8 can be connected via a bus or other means; Figure 8 shows an example of connection via a bus.

[0096] The second memory 1300, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules, such as the program instructions / modules corresponding to the UE context information interaction method executed in the first network device or the second network device provided in any embodiment of this application. The second processor 1400 implements the aforementioned UE context information interaction method executed in the core network device by running the software programs, instructions, and modules stored in the second memory 1300.

[0097] The second memory 1300 may primarily include a second stored program area and a second stored data area, wherein the second stored program area may store the operating system and application programs required for at least one function. Furthermore, the second memory 1300 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some instances, the second memory 1300 may further include memory remotely located relative to the second processor 1400, and these remote memories may be connected to the device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0098] One embodiment of this application also provides a computer-readable storage medium storing computer-executable instructions for performing the UE context information interaction method as provided in any embodiment of this application.

[0099] One embodiment of this application also provides a computer program product, including a computer program or computer instructions, which are stored in a computer-readable storage medium. The processor of a network device reads the computer program or computer instructions from the computer-readable storage medium and executes the computer program or computer instructions, causing the network device to perform the UE context information interaction method provided in any embodiment of this application applied to the network device. Alternatively, the processor of a core network device reads the computer program or computer instructions from the computer-readable storage medium and executes the computer program or computer instructions, causing the core network device to perform the UE context information interaction method provided in the embodiment of this application applied to the core network device.

[0100] According to the UE context information interaction method provided in the embodiments of this application, after the first network device receives an RRC re-establishment request message or an RRC recovery request message, if the first network device does not have UE context information and cannot obtain UE context information from the second device, it can send a first indication message to the core network device. This can drive the core network device to send a second indication message to the second network device based on the first indication message to obtain the UE context information stored in the second network device. In this way, even if the acquisition of UE context information based on the XN interface fails, the core network device can still ensure that it can obtain the UE context information. This reduces the impact of the failure to acquire UE context information based on the XN interface on the acquisition of UE context information, thereby improving the success rate of the first network device in obtaining UE context information from the second network device. This helps to improve the success rate of RRC re-establishment or RRC recovery, and thus improves the efficiency of rapid recovery of UE data services.

[0101] The system architecture and application scenarios described in this application are intended to more clearly illustrate the technical solutions of this application and do not constitute a limitation on the technical solutions provided in this application. Those skilled in the art will understand that as system architectures evolve and new application scenarios emerge, the technical solutions provided in this application are also applicable to similar technical problems.

[0102] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0103] In hardware implementations, the division between functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0104] The terms “component,” “module,” “system,” etc., used in this specification are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, or a computer. As illustrated, applications running on computing devices and computing devices can both be components. One or more components may reside in a process or execution thread, and components may be located on a single computer or distributed among two or more computers. Furthermore, these components can be executed from various computer-readable media on which various data structures are stored. Components can communicate, for example, via local or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component between a local system, a distributed system, or a network, such as the Internet interacting with other systems via signals).

Claims

1. A UE context information interaction method, applied to a first network device, the method comprising: Receive Radio Resource Control (RRC) Re-establishment Request Message or RRC Recovery Request Message sent by the UE (User Equipment). If it is determined that the UE context information is not stored and the UE context information cannot be obtained from the second network device that stores the UE context information, a first indication message for obtaining the UE context information is sent to the core network device. The core network device receives an NG handover request message, wherein the NG handover request message includes the UE context information, the UE context information is obtained by the core network device from the second network device through a second indication message, and the second indication message is generated by the core network device based on the first indication message; Based on the UE context information in the NG handover request message, the RRC re-establishment or RRC recovery between the first network device and the UE is completed.

2. The UE context information interaction method according to claim 1, wherein, The step of completing the RRC re-establishment or RRC recovery between the first network device and the UE based on the UE context information in the NG handover request message includes: Based on the UE context information in the NG handover request message, send an RRC re-establishment message or an RRC recovery message to the UE; The first network device receives an RRC re-establishment completion message or an RRC recovery completion message from the UE to complete the RRC re-establishment or RRC recovery between the first network device and the UE.

3. The UE context information interaction method according to claim 1, wherein, The situation where the UE context information cannot be obtained from the second network device storing the UE context information is determined by any one of the following: There is no XN interface between it and the second network device; The system receives a UE context retrieval failure message sent by the second network device, wherein the UE context retrieval failure message is a response message from the second network device to a UE context retrieval request message sent by the first network device.

4. The UE context information interaction method according to claim 1 further includes: Send an NG handover confirmation message to the core network equipment in response to the NG handover request; The core network device receives a downlink radio access network state transition message, wherein the downlink radio access network state transition message is generated by the core network device based on the packet data sequence number transmission information of the UE sent by the second network device, the downlink radio access network state transition message includes the packet data sequence number transmission information, the packet data sequence number transmission information is obtained by the second network device based on the NG handover command message sent by the core network device, and the NG handover command message is generated by the core network device based on the NG handover confirmation message; Based on the packet data sequence number transmission information in the downlink radio access network state transition message, the data backhaul is completed, and an NG handover notification message is sent to the core network device to notify the core network device to perform a downlink data path handover operation.

5. The UE context information interaction method according to claim 4 further includes: Send an RRC reconfiguration message to the UE; The system receives an RRC reconfiguration complete message from the UE to complete the radio bearer activation operation of the UE. The RRC reconfiguration complete message is sent by the UE after completing the RRC reconfiguration based on the RRC reconfiguration message.

6. A UE context information interaction method, applied to a second network device, the method comprising: The core network device receives a second indication message sent by the core network device, wherein the second indication message is generated by the core network device based on a first indication message sent by the first network device; the first indication message is used to obtain UE context information; the first indication message is sent by the first network device to the core network device after receiving a Radio Resource Control (RRC) Re-establishment Request message or an RRC Recovery Request message sent by the UE, and after determining that the UE context information is not stored and cannot be obtained from the second network device that stores the UE context information. The UE context information is determined according to the second instruction message, and the UE context information is sent to the core network device, so that the core network device sends an NG handover request message including the UE context information to the first network device, thereby enabling the first network device to complete the RRC re-establishment or RRC recovery with the UE according to the UE context information in the NG handover request message.

7. The UE context information interaction method according to claim 6, wherein, The second indication message includes the UE context information identifier; Determining the UE context information according to the second indication message includes: The UE context information is determined based on the UE context information identifier in the second indication message.

8. The UE context information interaction method according to claim 6, wherein, The second indication message also includes integrity protection information for the UE context information and the first cell global identifier of the first network device; Sending the UE context information to the core network device includes: The UE context information is verified based on the integrity protection information; When the verification is successful, an NG handover request message including the first cell global identifier and the UE context information is generated; Send the NG handover request message to the core network equipment.

9. The UE context information interaction method according to claim 8, wherein, The NG handover request message also includes retrieving the UE context reason value; Sending the NG handover request message to the core network device includes: The core network device sends the NG handover request message to the core network device, so that the core network device cooperates with the second network device to perform NG handover based on the first cell global identifier according to the retrieved UE context reason value in the NG handover request message. During the NG handover process, the second network device does not send the handover command RRC reconfiguration message to the UE.

10. The UE context information interaction method according to claim 6, wherein, Before receiving the second indication message sent by the core network device, the method further includes: The first network device sends a UE context request message, which is used to request the UE context information. Determine whether it is connected to the same core network as the first network device; When it is determined that there is no connection to the same core network as the first network device, a message indicating failure to obtain UE context through the XN interface is sent to the first network device, wherein the message indicating failure to obtain UE context through the XN interface is used to trigger the first network device to send the first indication message to the core network device.

11. The UE context information interaction method according to claim 6, further comprising: The core network device receives an NG handover command message, wherein the NG handover command message is generated by the core network device based on the NG handover confirmation message sent by the first network device in response to the NG handover request message; Obtain the packet data sequence number transmission information of the UE according to the NG handover command message; An uplink radio access network state transition message including the packet data sequence number transmission information is generated, and the uplink radio access network state transition message is sent to the core network device, so that the core network device generates and sends a downlink radio access network state transition message to the first network device based on the packet data sequence number transmission information in the uplink radio access network state transition message, thereby enabling the first network device to complete data backhaul based on the downlink radio access network state transition message.

12. A UE context information interaction method, applied to a core network device, the method comprising: A first indication message for obtaining UE context information is received. The first indication message is sent by a first network device when it determines that the UE context information is not stored and the UE context information cannot be obtained from a second network device that stores the UE context information. A second indication message is generated based on the first indication message, and the UE context information is obtained from the second network device through the second indication message; An NG handover request message including the UE context information is generated and sent to the first network device, so that the first network device can complete the RRC re-establishment or RRC recovery with the UE based on the UE context information in the NG handover request message.

13. The UE context information interaction method according to claim 12, wherein, The first indication message includes the second cell global identifier of the second network device, and the second indication message includes the UE context information identifier; The step of obtaining the UE context information from the second network device via the second indication message includes: The routing path to the second network device is determined based on the global identifier of the second cell; The second indication message is sent to the second network device through the routing path, so that the second network device determines the UE context information based on the UE context information identifier in the second indication message; Receive the UE context information sent by the second network device.

14. The UE context information interaction method according to claim 12, further comprising: Receive an NG handover confirmation message sent by the first network device in response to the NG handover request message; The packet data sequence number transmission information of the UE is obtained from the second network device according to the NG handover confirmation message; Generate a downlink radio access network state transition message including the packet data sequence number transmission information, and send the downlink radio access network state transition message to the first network device; The first network device receives an NG handover notification message, which is sent by the first network device after completing data backhaul according to the packet data sequence number transmission information in the downlink radio access network state transition message; Perform a downlink data path switching operation based on the NG handover notification message.

15. The UE context information interaction method according to claim 14, wherein, The step of obtaining the packet data sequence number transmission information of the UE from the second network device according to the NG handover confirmation message includes: An NG handover command message is generated based on the NG handover confirmation message, and the NG handover command message is sent to the second network device so that the second network device can obtain the packet data sequence number transmission information of the UE based on the NG handover command message; Receive the packet data sequence number transmission information sent by the second network device.

16. A network device, comprising: At least one first processor; At least one first memory for storing at least one program; Wherein, at least one of the programs is run by at least one of the first processors to perform the UE context information interaction method according to any one of claims 1 to 11.

17. A core network device, comprising: At least one second processor; At least one second memory for storing at least one program; In this embodiment, at least one of the programs is run by at least one of the second processors to perform the UE context information interaction method according to any one of claims 12 to 15.

18. A computer-readable storage medium storing computer-executable instructions, wherein, The computer-executable instructions are used to execute the UE context information interaction method according to any one of claims 1 to 15.

19. A computer program product comprising a computer program or computer instructions, wherein, The computer program or the computer instructions are stored in a computer-readable storage medium. The processor of the network device reads the computer program or the computer instructions from the computer-readable storage medium and executes the computer program or the computer instructions, causing the network device to perform the UE context information interaction method according to any one of claims 1 to 11. Alternatively, the processor of the core network device reads the computer program or the computer instructions from the computer-readable storage medium and executes the computer program or the computer instructions, causing the core network device to perform the UE context information interaction method according to any one of claims 12 to 15.

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