Switching method, access network equipment, device and storage medium

Abstract

The invention provides a switching method, access network equipment, a device and a storage medium, and the method comprises the steps that the access network equipment carries out switching according to one or more of the current position of the access network equipment, the current position of a terminal served by the access network equipment and configuration information of operation administration and maintenance (OAM); determining a terminal needing to serve the access network equipment to reselect an access and mobility management function (AMF); initiating NG switching for the terminal to a first AMF (Advanced Media Function); wherein the first AMF is an AMF serving the terminal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wireless communication, and in particular to a switching method, an access network device, an apparatus, and a storage medium. BACKGROUND

[0002] In a wireless access and backhaul (WAB) scenario and a non-terrestrial network (NTN) scenario, for a connected terminal (or user equipment, UE) served by a WAB node or a connected UE served by a satellite base station, an NG switching process is used to implement access and mobility management function (AMF) relocation, that is, to change the AMF serving the UE. The traditional NG switching is triggered by the measurement results of the UE on the source cell and the target cell to trigger the NG switching preparation process. However, in the WAB scenario and the NTN scenario, the source radio access network (RAN) node and the target RAN node of the UE switching are actually the same network node, and even the source cell and the target cell are the same, so it is impossible to trigger the NG switching preparation process according to the measurement results of the UE on the source cell and the target cell. SUMMARY

[0003] The present application provides a switching method, an access network device, an apparatus, and a storage medium to solve the problem of how to trigger the NG switching for the UE to relocate the AMF in the WAB scenario or the NTN scenario.

[0004] In a first aspect, the present application provides a switching method applied to an access network device, comprising: determining that an access and mobility management function (AMF) needs to be relocated for a terminal served by the access network device according to one or more of the following: a current location of the access network device, a current location of the terminal served by the access network device, and configuration information of an operation administration and maintenance (OAM). initiating an NG switching for the terminal to a first AMF; wherein the first AMF is an AMF serving the terminal.

[0005] In some embodiments, the determining that the AMF needs to be relocated for the terminal served by the access network device according to one or more of the following: the current location of the access network device, the current location of the terminal served by the access network device, and the configuration information of the OAM, comprises: determining that the AMF needs to be relocated for the terminal served by the access network device in the case that one or more of the following conditions are met: The OAM configures a second AMF for a current location of the access network device; According to the configuration information of the OAM, it is determined that the current location of the access network device corresponds to the second AMF; The OAM configures to release or suspend the NG connection between the access network device and the first AMF; According to the configuration information of the OAM, it is determined that the current location of the terminal corresponds to the second AMF; The second AMF is different from the first AMF.

[0006] In some embodiments, the method further comprises: sending, to the second AMF, an NG setup request message, the NG setup request message containing a tracking area TA identity of an access network device service corresponding to the current location of the access network device and a base station identity corresponding to the current location of the access network device; or

[0007] sending, to the second AMF, a first radio access network configuration update message, the first radio access network configuration update message containing the TA identity of the access network device service corresponding to the current location of the access network device and / or the base station identity corresponding to the current location of the access network device.

[0008] In some embodiments, the NG handover for the terminal is used to change the AMF serving the terminal from the first AMF to the second AMF.

[0009] In some embodiments, the NG handover for the terminal is further used to switch the terminal in a first cell; wherein the first cell is a serving cell of the terminal.

[0010] In some embodiments, the method further comprises: sending, to the first AMF, a first NG handover requirement message, the first NG handover requirement message containing a TA identity corresponding to the current location of the terminal or an AMF identity corresponding to the current location of the terminal.

[0011] In some embodiments, the NG handover for the terminal is further used to switch the terminal from a first cell to a second cell; The first cell is a serving cell of the terminal, and the second cell is a cell configured by the OAM for the access network device service corresponding to the current location of the access network device.

[0012] In some embodiments, the method further comprises: sending, to the first AMF, a second NG handover requirement message, the second NG handover requirement message containing a TA identity of an access network device service corresponding to the current location of the access network device or an AMF identity corresponding to the current location of the access network device.

[0013] In some embodiments, the method further comprises: The terminal measures a measurement result of a first cell as a measurement result of a second cell, where the first cell has a co-location relationship or a correspondence relationship with the second cell. The measurement result of the second cell is included in the NG handover request message.

[0014] In some embodiments, the measurement result includes a beam measurement result.

[0015] In some embodiments, the method further includes: receiving an NG handover request message sent by the second AMF, the NG handover request message containing a cell identity of the first cell; According to the co-location relationship or the correspondence relationship between the first cell and the second cell, the target cell of the NG handover is determined as the second cell.

[0016] In some embodiments, the method further includes: The beam measurement result of the first cell is taken as the beam measurement result of the second cell, and a beam used for handover is determined based on the beam measurement result of the second cell; or

[0017] The beam used for handover is determined according to the first beam used by the terminal in the first cell.

[0018] In some embodiments, the method further includes: broadcasting a TA identity corresponding to the second cell and a cell identity.

[0019] In some embodiments, the method further includes: releasing the NG connection with the first AMF, or suspending the NG connection with the first AMF.

[0020] In some embodiments, the method further includes: In the case of suspending the NG connection with the first AMF, the first AMF is not selected as an AMF serving the terminal, or a paging message received from the first AMF is not broadcasted.

[0021] In some embodiments, suspending the NG connection with the first AMF includes: sending an NG connection suspension request to the first AMF; or

[0022] sending a second radio access network configuration update message to the first AMF, the second radio access network configuration update message containing a TA identity served by an access network device corresponding to a current location of the access network device.

[0023] In some embodiments, the method further includes: maintaining a stream control transmission protocol (SCTP) connection with the first AMF.

[0024] In a second aspect, the present application also provides an access network device, comprising a memory, a transceiver, and a processor; a memory for storing a computer program; a transceiver for transceiving data under the control of the processor; and a processor for reading the computer program in the memory and performing the following operations: determining that the terminal served by the access network device needs to reselect an access and mobility management function (AMF) according to one or more of the current location of the access network device, the current location of the terminal served by the access network device, and configuration information of an operation administration and maintenance (OAM); initiating an NG handover for the terminal to a first AMF; wherein the first AMF is an AMF serving the terminal.

[0025] In some embodiments, determining that the terminal served by the access network device needs to reselect an AMF according to one or more of the current location of the access network device, the current location of the terminal served by the access network device, and configuration information of an operation administration and maintenance (OAM) comprises: determining that the terminal served by the access network device needs to reselect an AMF in the case that one or more of the following conditions are met: the OAM configures a second AMF for the current location of the access network device; determining that the current location of the access network device corresponds to the second AMF according to the configuration information of the OAM; the OAM configures to release or suspend the NG connection between the access network device and the first AMF; determining that the current location of the terminal corresponds to the second AMF according to the configuration information of the OAM; wherein the second AMF is different from the first AMF.

[0026] In some embodiments, the operation further comprises: sending an NG setup request message to the second AMF, the NG setup request message containing a tracking area (TA) identity of the access network device served by the access network device corresponding to the current location of the access network device, and a base station identity corresponding to the current location of the access network device; or,

[0027] sending a first radio access network configuration update message to the second AMF, the first radio access network configuration update message containing the TA identity of the access network device served by the access network device corresponding to the current location of the access network device, and / or the base station identity corresponding to the current location of the access network device.

[0028] In some embodiments, the NG handover for the terminal is used to change the AMF serving the terminal from the first AMF to the second AMF.

[0029] In some embodiments, the NG handover for the terminal is further used to hand over the terminal in the first cell; and the first cell is a serving cell of the terminal.

[0030] In some embodiments, the operation further includes: sending, to the first AMF, a first NG handover request message, the first NG handover request message containing a TA identifier corresponding to the current location of the terminal or an AMF identifier corresponding to the current location of the terminal.

[0031] In some embodiments, the NG handover for the terminal is further used to hand over the terminal from the first cell to the second cell. The first cell is a serving cell of the terminal, and the second cell is a cell served by the access network device corresponding to the current location of the access network device and configured by the OAM.

[0032] In some embodiments, the operation further includes: sending, to the first AMF, a second NG handover request message, the second NG handover request message containing a TA identifier of a cell served by the access network device corresponding to the current location of the access network device or an AMF identifier corresponding to the current location of the access network device.

[0033] In some embodiments, the operation further includes: using a measurement result of the terminal measuring the first cell as a measurement result of the terminal measuring the second cell, wherein the first cell and the second cell have a co-location relationship or a corresponding relationship; including the measurement result of the second cell in the NG handover request message.

[0034] In some embodiments, the measurement result includes a beam measurement result.

[0035] In some embodiments, the operation further includes: receiving an NG handover request message sent by the second AMF, the NG handover request message containing a cell identifier of the first cell; determining, according to the co-location relationship or the corresponding relationship between the first cell and the second cell, that the target cell of the NG handover is the second cell.

[0036] In some embodiments, the operation further includes: using a beam measurement result of the first cell as a beam measurement result of the second cell, and determining a beam used for handover based on the beam measurement result of the second cell; or

[0037] determining the beam used for handover according to a first beam used by the terminal in the first cell.

[0038] In some embodiments, the operation further includes: broadcasting a TA identifier and a cell identifier corresponding to the second cell.

[0039] In some embodiments, the operation further includes: releasing the NG connection with the first AMF, or suspending the NG connection with the first AMF.

[0040] In some embodiments, the operation further includes: In the case of suspending the NG connection with the first AMF, not selecting the first AMF as an AMF serving the terminal for the terminal, or not broadcasting a paging message received from the first AMF.

[0041] In some embodiments, suspending the NG connection with the first AMF includes: sending an NG connection suspension request to the first AMF; or

[0042] sending a second radio access network configuration update message to the first AMF, the second radio access network configuration update message containing a TA identity of an access network device serving the current location of the access network device.

[0043] In some embodiments, the operation further includes: maintaining a stream control transmission protocol (SCTP) connection with the first AMF.

[0044] In a third aspect, the present application also provides a switching device, comprising: a determination unit configured to determine that an access and mobility management function (AMF) needs to be reselected for a terminal served by an access network device according to one or more of a current location of the access network device, a current location of the terminal served by the access network device, and configuration information of an operation administration and maintenance (OAM). a switching unit configured to initiate an NG switching for the terminal to a first AMF, wherein the first AMF is an AMF serving the terminal.

[0045] In some embodiments, the determination that the AMF needs to be reselected for the terminal served by the access network device according to one or more of the current location of the access network device, the current location of the terminal served by the access network device, and the configuration information of the OAM includes: determining that the AMF needs to be reselected for the terminal served by the access network device in the case that one or more of the following conditions is met: the OAM configures a second AMF for the current location of the access network device; the configuration information of the OAM indicates that the current location of the access network device corresponds to the second AMF; the OAM configures to release or suspend the NG connection between the access network device and the first AMF; the configuration information of the OAM indicates that the current location of the terminal corresponds to the second AMF. wherein the second AMF is different from the first AMF.

[0046] In some embodiments, the apparatus further includes a first sending unit configured to: send, to the second AMF, an NG setup request message, the NG setup request message containing a tracking area, TA, identity of a serving access network device of the access network device corresponding to the current location of the access network device and a base station identity corresponding to the current location of the access network device; or

[0047] send, to the second AMF, a first radio access network configuration update message, the first radio access network configuration update message containing the TA identity of the serving access network device of the access network device corresponding to the current location of the access network device and / or the base station identity corresponding to the current location of the access network device.

[0048] In some embodiments, the NG handover for the terminal is configured to change an AMF serving the terminal from the first AMF to the second AMF.

[0049] In some embodiments, the NG handover for the terminal is further configured to hand over the terminal in a first cell; wherein the first cell is a serving cell of the terminal.

[0050] In some embodiments, the apparatus further includes a second sending unit configured to: send, to the first AMF, a first NG handover request message, the first NG handover request message containing a TA identity corresponding to a current location of the terminal or an AMF identity corresponding to the current location of the terminal.

[0051] In some embodiments, the NG handover for the terminal is further configured to hand over the terminal from a first cell to a second cell; wherein the first cell is a serving cell of the terminal, and the second cell is a cell of the access network device serving the access network device corresponding to the current location of the access network device.

[0052] In some embodiments, the apparatus further includes a third sending unit configured to: send, to the first AMF, a second NG handover request message, the second NG handover request message containing the TA identity of the serving access network device of the access network device corresponding to the current location of the access network device or the AMF identity corresponding to the current location of the access network device.

[0053] In some embodiments, the apparatus further includes a first processing unit configured to: use a measurement result of a first cell measured by the terminal as a measurement result of a second cell measured by the terminal, wherein the first cell has a co-sited relationship or a corresponding relationship with the second cell; include the measurement result of the second cell in the NG handover request message.

[0054] In some embodiments, the measurement result comprises a beam measurement result.

[0055] In some embodiments, the apparatus further comprises a second processing unit configured to: receive a NG handover request message sent by the second AMF, the NG handover request message comprising a cell identity of the first cell; determine, according to a co-sited relationship or a corresponding relationship between the first cell and the second cell, that the target cell of the NG handover is the second cell.

[0056] In some embodiments, the apparatus further comprises a third processing unit configured to: determine the beam for the handover based on a beam measurement result of the second cell, wherein the beam measurement result of the first cell is used as the beam measurement result of the second cell; or

[0057] determine the beam for the handover according to a first beam used by the terminal in the first cell.

[0058] In some embodiments, the apparatus further comprises a broadcasting unit configured to: broadcast a TA identity and a cell identity corresponding to the second cell.

[0059] In some embodiments, the apparatus further comprises a fourth processing unit configured to: release the NG connection with the first AMF, or suspend the NG connection with the first AMF.

[0060] In some embodiments, the fourth processing unit is further configured to: in a case where the NG connection with the first AMF is suspended, not select the first AMF as an AMF serving the terminal, or not broadcast a paging message received from the first AMF.

[0061] In some embodiments, suspending the NG connection with the first AMF comprises: sending a NG connection suspension request to the first AMF; or

[0062] sending a second radio access network configuration update message to the first AMF, the second radio access network configuration update message comprising a TA identity of a TA served by the access network device corresponding to a current location of the access network device.

[0063] In some embodiments, the fourth processing unit is further configured to: maintain a stream control transmission protocol (SCTP) connection with the first AMF.

[0064] In a fourth aspect, the present application further provides a non-transitory readable storage medium, the non-transitory readable storage medium storing a program, the program being used to make a processor execute the handover method according to the first aspect.

[0065] In a fifth aspect, the present application also provides a communication device, wherein a program is stored in the communication device, and the program is used to make the communication device execute the switching method in the first aspect.

[0066] In a sixth aspect, the present application also provides a processor-readable storage medium, wherein a program is stored in the processor-readable storage medium, and the program is used to make a processor execute the switching method in the first aspect.

[0067] In a seventh aspect, the present application also provides a chip product, wherein a program is stored in the chip product, and the program is used to make the chip product execute the switching method in the first aspect.

[0068] The switching method, the access network device, the apparatus and the storage medium provided by the present application can determine that the UE served by the access network device needs to reselect an AMF according to one or more of the current location of the access network device, the current location of the UE served by the access network device and the configuration information of the OAM, and initiate the NG switching of the UE to the first AMF in the case that it is determined that the UE needs to reselect an AMF, so that the NG switching preparation process can be triggered without the measurement result of the UE on the source cell and the target cell, the problem of triggering the NG switching for the UE to reselect the AMF in the NTN or WAB scenario is solved, the UE can be provided with better network service, and the user experience is improved. BRIEF DESCRIPTION OF DRAWINGS

[0069] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the embodiments or the related art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0070] Figure 1 The WAB structure schematic diagram provided by the related art.

[0071] Figure 2 The WAB scenario example diagram provided by the related art.

[0072] Figure 3 One of the NTN scenario example diagrams provided by the related art.

[0073] Figure 4 The second NTN scenario example diagram provided by the related art.

[0074] Figure 5 The flowchart of the switching method provided by the embodiments of the present application.

[0075] Figure 6 An example diagram of a WAB scenario NG handover procedure is provided for embodiments of the present application.

[0076] Figure 7 An example diagram of an NTN scenario NG handover procedure is provided for embodiments of the present application.

[0077] Figure 8 An example diagram of beam selection is provided for embodiments of the present application.

[0078] Figure 9 An example diagram of the structure of an access network device is provided for embodiments of the present application.

[0079] Figure 10 An example diagram of the structure of a handover device is provided for embodiments of the present application. DETAILED DESCRIPTION

[0080] The term "and / or" in the embodiments of the present application describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the three cases of A alone, A and B together, and B alone. The character " / " generally represents an "or" relationship between the associated objects before and after it.

[0081] The term "multiple" in the embodiments of the present application means two or more, and other quantifiers are similar.

[0082] The terms "first", "second", and the like in the embodiments of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second" are usually of a kind, and do not limit the number of objects, for example, the first object can be one or more.

[0083] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0084] In order to facilitate a clearer understanding of the technical solutions of the embodiments of the present application, first, some technical contents related to the embodiments of the present application are introduced.

[0085] Figure 1 An example diagram of the structure of WAB provided for related art is as follows: Figure 1As shown, the WAB node contains two functional modules, WAB-gNB (WAB base station) and WAB-MT (WAB terminal). The WAB-gNB has complete base station functions and can establish an NG interface with the 5G core network (5GC), thereby enabling the WAB node to serve the UE. The WAB-MT has partial UE functions and can access a RAN node (referred to as a backhaul radio access network (BH-RAN) node) serving the WAB-MT and a 5G core network (referred to as a backhaul 5G core network (BH-5GC)) through a new radio (NR) Uu interface. The packet data unit (PDU) session (referred to as a backhaul packet data unit (BH PDU) session) established for the WAB-MT can backhaul the NG data packets of the WAB-gNB (including UE traffic) to the core network, and the WAB node supports local splitting, local traffic, and mobile edge computing (MEC). Since the WAB node supports UE functions, it can be installed on an airplane, cruise ship, helicopter, and vehicle to provide 5G access for the UE. Figure 1 In the figure, NG-C and NG-U respectively represent the NG control plane interface and the NG user plane interface, and Xn-C and Xn-U respectively represent the Xn control plane interface and the Xn user plane interface.

[0086] For the WAB scenario, the configurations used by the WAB-gNB in the process of serving the UE, such as the cell identifier (Cell ID) or tracking area code (TAC) broadcast by the WAB-gNB, and the AMF address connected by the WAB-gNB through the NG interface, are configured by the operation management (OAM) according to the location of the WAB node. The WAB-MT can obtain the geographical position of the current WAB node or the Cell ID / TAC of the BH-RAN node as the location information of the WAB node and report it to the OAM, and then the OAM configures the parameters of the WAB-gNB according to the location information of the WAB node.

[0087] Figure 2 The WAB scenario example provided by the related art is shown in FIG. 1. Figure 2 As shown in FIG. 2, the vehicle-mounted WAB node serves the UE on the vehicle. When the WAB node moves within a limited area, even if the NG-RAN node serving the WAB-MT is switched, as long as the WAB node is always within the control range of an AMF, the WAB node does not need to change the connected AMF and the broadcasted TAC / Cell ID, as shown in FIG. 3. Figure 2As shown in scenario A in FIG. 1, when the WAB node moves out of the control range of the current AMF, the WAB node needs to connect to a new AMF, and the TAC and Cell ID (including Physical Cell ID (PCI) and NR Cell Global Identifier (NCGI)) broadcast by the WAB node also need to be changed, as shown in scenario B in FIG. 1. Figure 2 As shown in scenario B in FIG. 1, when the TAC broadcast by the WAB node changes, the UE in the RRC idle state and the RRC inactive state can trigger the registration update procedure by reading the TAC, to transfer the context of the UE from the original AMF to the new AMF. Meanwhile, the UE in the RRC connected state also needs to change the serving AMF from the original AMF to the new AMF.

[0088] For the NTN scenario, because the coverage of a satellite is very wide, a satellite cell can cover multiple geographical areas controlled by multiple AMFs at the same time, and the control areas of the AMFs do not overlap. In this case, the satellite base station (or NTN base station) is connected to multiple AMFs at the same time, and the cell broadcasts multiple TAs corresponding to the AMFs at the same time, and each TA corresponds to a fixed geographical area. Because the TAC broadcast by the satellite cell does not change, the UE in the RRC idle state and the RRC inactive state does not trigger the registration update when moving within the cell, and the AMF registered by the UE does not change. For the UE in the RRC connected state, the satellite base station needs to ensure that the UE is connected to the AMF corresponding to the location of the UE. Figure 3 and Figure 4 Two different NTN scenarios are exemplified in FIG. 2 and FIG. 3, respectively, as shown in FIG. 2 and FIG. 3. Figure 3 In the scenario shown in FIG. 2, the base station function is realized by the ground gateway station and the satellite together, and the ground gateway station is connected to multiple AMFs. Figure 4 In the scenario shown in FIG. 3, the base station is located on the satellite (gNB onboard), and the onboard base station is connected to multiple AMFs through multiple ground gateway stations.

[0089] In the WAB scenario and the NTN scenario, for the UE in the connected state served by the WAB node or the UE in the connected state served by the satellite base station, the NG handover procedure is adopted to realize the AMF relocation of the UE, that is, to change the AMF serving the UE. The traditional NG handover is triggered by the measurement results of the UE on the source cell and the target cell, but in the WAB scenario and the NTN scenario, the source RAN node and the target RAN node of the UE actually switch are the same network node, or even the source cell and the target cell are the same, and the NG handover preparation cannot be triggered according to the measurement results of the UE on the source cell and the target cell. To this end, the present application provides a solution.

[0090] It should be noted that although the embodiments of the present application are exemplified in the WAB scenario and the NTN scenario (the feature of the WAB node is that the cell coverage is small, and the feature of the NTN base station is that the cell coverage is large, the WAB scenario is taken as an example when the mobile base station coverage is small, and the NTN scenario is taken as an example when the mobile base station coverage is large), the technical solutions of the present application are not limited to these two scenarios, but can also be other scenarios of mobile access network equipment which are well known to those skilled in the art or may appear in the future, and the present application is not limited.

[0091] Figure 5 The flowchart of the handover method provided by the embodiments of the present application is shown in the figure, and the method is applied to an access network equipment, such as Figure 5 As shown in the figure, the method comprises the following steps 501 and 502.

[0092] Step 501, according to one or more of the current location of the access network equipment, the current location of the terminal served by the access network equipment, and the configuration information of the operation management and maintenance (OAM), it is determined that the terminal served by the access network equipment needs to be reselected for access and mobility management function (AMF).

[0093] Specifically, the present application provides a handover method for implementing AMF relocation, and the access network equipment can determine that the UE served by the access network equipment needs to be reselected for AMF according to one or more of the current location of the access network equipment, the current location of the UE served by the access network equipment, and the configuration information of the OAM.

[0094] In some embodiments, the access network equipment can be a WAB node or an NTN base station.

[0095] For example, in the WAB scenario, the WAB node can determine that the UE served by the WAB node needs to be reselected for AMF according to the current location of the WAB node and / or the configuration information of the OAM. That is, the WAB node can be triggered to reselect AMF for the UE by the change of the location of the WAB node and / or the configuration information of the OAM.

[0096] For another example, in the NTN scenario, the NTN base station can determine that the UE served by the NTN base station needs to be reselected for AMF according to the current location of the UE and / or the configuration information of the OAM. That is, the NTN base station can be triggered to reselect AMF for the UE by the change of the location of the UE and / or the configuration information of the OAM.

[0097] Step 502, initiating NG handover for the terminal to the first AMF; wherein the first AMF is the AMF serving the terminal.

[0098] Specifically, when the access network device determines that the UE needs to reselect the AMF, the access network device can initiate the NG handover for the UE to the AMF currently serving the UE (i.e., the first AMF, or the source AMF), to realize the AMF relocation of the UE. The present application does not limit the specific manner in which the access network device initiates the NG handover for the terminal to the first AMF, for example: the access network device can send a handover required (Handover Required) message to the first AMF to change the AMF serving the UE; or the access network device can initiate the NG handover for the terminal to the first AMF through other ways other than sending the handover required message, which is not limited by the present application.

[0099] The switching method provided by the embodiments of the present application can determine that the UE served by the access network device needs to reselect the AMF according to one or more of the current location of the access network device, the current location of the UE served by the access network device, and the configuration information of the OAM, and initiate the NG handover for the UE to the first AMF when it is determined that the UE needs to reselect the AMF, so that the NG handover preparation process can be triggered without the measurement results of the UE on the source cell and the target cell, the problem of triggering the NG handover for the UE to reselect the AMF in the NTN or WAB scenario is solved, the UE can be provided with better network service, and the user experience is improved.

[0100] In some embodiments, determining that the terminal served by the access network device needs to reselect the AMF according to one or more of the current location of the access network device, the current location of the terminal served by the access network device, and the configuration information of the OAM, comprises: The determination that the terminal served by the access network device needs to reselect the AMF is based on one or more of the following conditions: (1) The OAM configures a second AMF for the current location of the access network device, wherein the second AMF is different from the first AMF.

[0101] For example, the OAM configures a new AMF (i.e., the second AMF) for the WAB node according to the current location of the WAB node, and since the second AMF is different from the first AMF, the WAB node determines that the UE served by the WAB node needs to reselect the AMF in this case. The WAB node can initiate the NG handover for the UE to the first AMF, and change the AMF serving the UE from the first AMF to the second AMF.

[0102] (2) The access network device determines that the current location of the access network device corresponds to the second AMF according to the configuration information of the OAM, wherein the second AMF is different from the first AMF.

[0103] For example, the OAM configures different AMFs for different locations of the WAB node, the WAB node determines, according to the configuration information of the OAM, that the AMF corresponding to the current location of the WAB node is the second AMF, and the WAB node determines that it needs to connect to the second AMF. Since the second AMF is different from the first AMF, the WAB node determines that the AMF needs to be reselected for the UE served by the WAB node in this case. The WAB node can initiate an NG handover for the UE to the first AMF, and change the AMF serving the UE from the first AMF to the second AMF.

[0104] (3) The OAM configures to release or suspend the NG connection between the access network device and the first AMF.

[0105] For example, according to the current location of the WAB node, the OAM configures the WAB node to release or suspend the NG connection with the first AMF, and the WAB node determines that the AMF needs to be reselected for the UE served by the WAB node in this case. The WAB node can initiate an NG handover for the UE to the first AMF, and change the AMF serving the UE from the first AMF to another AMF.

[0106] (4) According to the configuration information of the OAM, it is determined that the current location of the terminal corresponds to the second AMF, and the second AMF is different from the first AMF.

[0107] For example, the NTN base station detects that the UE moves to a new location, which is not within the service area corresponding to the first AMF configured by the OAM but is within the service area corresponding to the second AMF. The NTN base station determines that the AMF needs to be reselected for the UE in this case. The NTN base station can initiate an NG handover for the UE to the first AMF, and change the AMF serving the UE from the first AMF to the second AMF.

[0108] In some embodiments, the method further comprises: sending an NG setup request message to the second AMF, the NG setup request message containing a TA identifier of the access network device served by the access network device corresponding to the current location of the access network device, and a base station identifier corresponding to the current location of the access network device; or,

[0109] sending a first radio access network configuration update message to the second AMF, the first radio access network configuration update message containing a TA identifier of the access network device served by the access network device corresponding to the current location of the access network device and / or a base station identifier corresponding to the current location of the access network device.

[0110] Specifically, if the access network device determines that the AMF serving the UE needs to be changed from the first AMF to the second AMF, but the access network device has not established an NG connection with the second AMF, the access network device can establish an NG connection with the second AMF, send an NG Setup Request message to the second AMF, the NG Setup Request message containing a TA identity (such as a TAC) served by the access network device corresponding to the current location of the access network device, and a base station identity (such as a gNB ID) corresponding to the current location of the access network device.

[0111] In some embodiments, the access network device can include the TA identity corresponding to the current location of the access network device in the Supported TA List in the NG Setup Request message, and set the Global RAN Node ID in the NG Setup Request message to the base station identity corresponding to the current location of the access network device.

[0112] For example, the second AMF is an AMF corresponding to the current location of the WAB node configured by the OAM, and the WAB node has not established an NG connection with the second AMF. The WAB node triggers the establishment of an NG connection with the second AMF, and sends an NG Setup Request message to the second AMF. The Supported TA List in the NG Setup Request message contains the TAC corresponding to the current location of the WAB node, and the Global RAN Node ID in the NG Setup Request message is set to the gNB ID corresponding to the current location of the WAB node.

[0113] If the access network device has already established an NG connection with the second AMF, the access network device can update the NG connection with the second AMF, and send a first RAN Configuration Update message to the second AMF. The first RAN Configuration Update message contains a TA identity served by the access network device corresponding to the current location of the access network device and / or a base station identity corresponding to the current location of the access network device, to update the TA identity and / or the base station identity corresponding to the current location of the access network device.

[0114] In some embodiments, the access network device can include the TA identity corresponding to the current location of the access network device in the Supported TA List in the first RAN Configuration Update message, and / or set the Global RAN Node ID in the first RAN Configuration Update message to the base station identity corresponding to the current location of the access network device.

[0115] For example, the second AMF is an AMF corresponding to the current location of the WAB node configured by the OAM, the WAB node has established an NG connection with the second AMF, and the WAB node can update the TA identifier and / or base station identifier corresponding to the current location of the WAB node through the first radio access network configuration update message. The WAB node can include the TAC corresponding to the current location of the WAB node in the Supported TA List in the first radio access network configuration update message, and / or set the Global RAN Node ID in the first radio access network configuration update message to the gNB ID corresponding to the current location of the WAB node.

[0116] In some embodiments, the NG handover for the terminal is also used to hand over the terminal in the first cell; wherein the first cell is a serving cell of the terminal.

[0117] For example, in an NTN scenario, a satellite cell can simultaneously cover multiple geographical areas controlled by AMFs, and the NTN base station initiates an NG handover for a UE in a case where it is determined that the UE needs to be reselected for an AMF, the NG handover being used to change the AMF serving the UE from a first AMF to a second AMF, but the serving cell of the UE remaining unchanged.

[0118] In some embodiments, the method further comprises: sending a first NG handover requirement message to the first AMF, the first NG handover requirement message containing a TA identifier corresponding to the current location of the terminal or an AMF identifier corresponding to the current location of the terminal.

[0119] Specifically, in order to enable the first AMF to select a second AMF corresponding to the current location of the UE as a target AMF, the access network device can send a first NG handover requirement (Handover Required) message to the first AMF, the first NG handover requirement message containing a TA identifier corresponding to the current location of the UE, or an AMF identifier corresponding to the current location of the UE, since the TA corresponds to the second AMF, so that the first AMF can determine the target AMF according to the TA identifier or the AMF identifier in the first NG handover requirement message.

[0120] In some embodiments, the access network device can set the SelectedTAI field of the Target ID in the first NG handover requirement message to the TAI corresponding to the current location of the UE, or add the AMF identifier corresponding to the current location of the UE in the first NG handover requirement message.

[0121] For example, in the NTN scenario, in order to enable the first AMF to select the AMF corresponding to the current location of the UE as the target AMF, the NTN base station can send a first NG handover required message to the first AMF, set the Selected TAI field of the Target ID in the first NG handover required message to the TAI corresponding to the current location of the UE, or add the AMF identifier corresponding to the current location of the UE in the first NG handover required message.

[0122] In some embodiments, the NG handover for the terminal is also used to switch the terminal from the first cell to the second cell; wherein the first cell is a serving cell of the terminal, and the second cell is a cell served by the access network device corresponding to the current location of the access network device.

[0123] For example, in the WAB scenario, the WAB node moves to a new location and determines that the UE served by the WAB node needs to reselect the AMF, and then the WAB node initiates the NG handover for the UE. The NG handover is not only used to change the AMF serving the UE from the first AMF to the second AMF, but also used to switch the UE from the first cell to the second cell, that is, not only the AMF serving the UE needs to be changed, but also the cell serving the UE needs to be changed.

[0124] In some embodiments, the method further comprises: sending a second NG handover required message to the first AMF, the second NG handover required message containing the TA identifier of the access network device served by the access network device corresponding to the current location of the access network device, or the AMF identifier corresponding to the current location of the access network device.

[0125] Specifically, in order to enable the first AMF to select the second AMF corresponding to the current location of the access network device as the target AMF, the access network device can send a second NG handover required message to the first AMF, the second NG handover required message containing the TA identifier of the access network device served by the access network device corresponding to the current location of the access network device, or the AMF identifier corresponding to the current location of the access network device, since the TA corresponds to the second AMF, so that the first AMF can determine the target AMF according to the TA identifier or the AMF identifier in the second NG handover required message.

[0126] In some embodiments, the access network device can set the Selected TAI field of the Target ID in the second NG handover required message to the TAI corresponding to the current location of the access network device, or add the AMF identifier corresponding to the current location of the access network device in the second NG handover required message.

[0127] For example, in the WAB scenario, in order to enable the first AMF to select the AMF corresponding to the current location of the WAB node as the target AMF, the WAB node can send a second NG handover request message to the first AMF, set the Selected TAI field of the Target ID in the second NG handover request message to the TAI corresponding to the current location of the WAB node, or add the AMF identifier corresponding to the current location of the WAB node in the second NG handover request message.

[0128] In some embodiments, the method further comprises: The measurement result of the terminal for the first cell is taken as the measurement result of the terminal for the second cell, wherein the first cell and the second cell have a co-location relationship or a corresponding relationship. The measurement result of the second cell is contained in the NG handover request message.

[0129] Specifically, the NG handover in the present application is not triggered by the measurement result of the UE for the source cell and the target cell, so when the access network device initiates the NG handover, the UE may not have measured the second cell. Embodiment 1 provides a solution for how to select the target cell of the UE handover in the case of lacking the measurement result of the second cell: the access network device can take the measurement result of the UE for the first cell as the measurement result of the UE for the second cell, and send the measurement result of the second cell in the NG handover request message to the first AMF.

[0130] For example, the WAB node needs to be connected to a new AMF because it moves to a new location area, and the TAC and cell identifier broadcast by each serving cell of the WAB node also needs to be changed. The changed cell identifier is referred to as new Cell ID, and the unchanged cell identifier is referred to as old Cell ID. The cell of the new Cell ID (i.e. the second cell) and the cell of the old Cell ID (i.e. the first cell) are co-located or in a one-to-one correspondence. The UE is always served by the WAB node during the movement of the WAB node, so although the cell identifier broadcast by the WAB node changes from the old Cell ID to the new Cell ID, the signal quality measured by the UE for the serving cell of the WAB node does not change. Therefore, the measurement result of the UE for the first cell can be taken as the measurement result of the UE for the second cell.

[0131] According to the conventional NG handover, the source access network node transmits an RRC container HandoverPreparationInformation (Handover Preparation Information) to the source AMF when sending the NG handover request message, and the Handover Preparation Information contains the measurement result candidateCellInfoList (candidate cell information list) of the candidate cell.

[0132] In this embodiment, the WAB node can include the measurement result of the UE on the first cell as the measurement result of the UE on the second cell in the candidateCellInfoList of the HandoverPreparationInformation. In this way, the WAB node can determine to hand over the UE to the second cell based on the measurement result of the second cell included in the candidateCellInfoList after receiving the Handover Request message sent by the target AMF.

[0133] In some embodiments, the measurement result includes a beam measurement result.

[0134] Specifically, in order to select a beam for handover, the access network device can include the beam measurement result of the UE on the first cell as the beam measurement result of the UE on the second cell in the NG handover request message sent to the first AMF.

[0135] For example, in the WAB scenario, the UE is handed over from the first cell to the second cell in the RACH-less HO manner, in order to select a beam for RACH-less HO, the WAB node can include the beam measurement result of the UE on the first cell as the beam measurement result of the second cell in the candidateCellInfoList. The WAB node can determine the beam for RACH-less HO according to the beam measurement result of the UE on the second cell.

[0136] In some embodiments, the above-mentioned beam can be a synchronization signal block (Synchronization Signal and PBCH Block, SSB) beam or a channel state information reference signal (Channel State Information-Reference Signal, CSI-RS) beam.

[0137] In some embodiments, the method further includes: receiving a NG handover request message sent by the second AMF, the NG handover request message including a cell identifier of the first cell; determining the target cell of the NG handover to be the second cell according to the co-sited relationship or the corresponding relationship between the first cell and the second cell.

[0138] Specifically, the embodiment provides a solution 2 for how to select a target cell for UE handover in the case that the measurement result of the second cell is missing: the access network device can determine the target cell for the NG handover as the second cell according to the colocation relationship or the correspondence relationship between the first cell and the second cell, in the case that the received NG handover request message contains the cell identifier of the first cell.

[0139] For example, the WAB node receives the NG handover request message, and the HandoverPreparationInformation in the NG handover request message carries the cell identifier of the first cell, the measurement result of the first cell by the UE, and the like. The WAB node learns that the UE is served by the first cell through the information of the first cell carried by the HandoverPreparationInformation, and then determines that the UE needs to be handed over to the second cell according to the colocation relationship or the correspondence relationship between the first cell and the second cell.

[0140] In some embodiments, the method further includes: The beam measurement result of the first cell is taken as the beam measurement result of the second cell, and the beam for handover is determined based on the beam measurement result of the second cell; or

[0141] The beam for handover is determined according to the first beam used by the terminal in the first cell.

[0142] Specifically, in some embodiments, in the case that the received NG handover request message contains the beam measurement result of the first cell, the access network device can take the beam measurement result of the first cell as the beam measurement result of the second cell (for example, according to the colocation relationship or the correspondence relationship between the first cell and the second cell), and determine the beam for handover according to the beam measurement result of the second cell.

[0143] In some embodiments, the access network device can determine the beam for handover according to the first beam used by the terminal in the first cell. For example, the access network device can directly select the beam in the second cell that has a colocation relationship (or a correspondence relationship) with the first beam used by the UE in the first cell for handover. For example, if the UE uses beam a in the first cell, it can be determined that the UE uses beam b in the second cell that has a colocation relationship (or a correspondence relationship) with beam a for RACH-less HO.

[0144] In some embodiments, the method further includes: The TA identifier and the cell identifier corresponding to the second cell are broadcasted.

[0145] For example, the WAB node needs to connect to a new AMF because it moves to a new location area, the TA identity and cell identity broadcasted by the WAB node per serving cell also need to be changed, the second cell is a cell served by the WAB node corresponding to the current location of the WAB node, and the WAB node needs to broadcast the TA identity and cell identity corresponding to the second cell.

[0146] In some embodiments, the method further includes: releasing the NG connection with the first AMF, or suspending the NG connection with the first AMF.

[0147] Specifically, after the access network device changes the AMF serving the UE from the first AMF to another AMF, the access network device can release the NG connection with the first AMF, or suspend the NG connection with the first AMF.

[0148] In some embodiments, suspending the NG connection with the first AMF includes: sending an NG connection suspension request to the first AMF; or

[0149] sending a second radio access network configuration update message to the first AMF, the second radio access network configuration update message containing a TA identity served by the access network device corresponding to the current location of the access network device.

[0150] Specifically, the access network device suspending the NG connection with the first AMF can have two different implementations.

[0151] Method 1: The access network device can directly send an NG connection suspension request to the first AMF, requesting to suspend the NG connection with the first AMF.

[0152] Method 2: The access network device can implicitly indicate to suspend the NG connection with the first AMF by sending a second radio access network configuration update message to the first AMF, since the second radio access network configuration update message contains a TA identity served by the access network device corresponding to the current location of the access network device, the AMF corresponding to the TA identity is not the first AMF, so the first AMF can determine that the access network device needs to suspend the NG connection with the first AMF after receiving the second radio access network configuration update message.

[0153] In some embodiments, the method further includes: In the case of suspending the NG connection with the first AMF, the first AMF is not selected as the AMF serving the terminal for the terminal, or the paging message received from the first AMF is not broadcasted.

[0154] For example, in the case that the access network device suspends the NG connection with the first AMF, when the UE establishes an RRC connection with the access network device, the access network device does not select the first AMF as the AMF serving the UE.

[0155] For example, in the case that the access network device suspends the NG connection with the first AMF, if the access network device receives a paging message of the first AMF, the access network device does not broadcast the paging message.

[0156] In some embodiments, in the case that the access network device releases or suspends the NG connection with the first AMF, the access network device can still maintain a Stream Control Transmission Protocol (SCTP) connection with the first AMF.

[0157] The method provided by the above embodiments of the present application is illustrated below by specific examples.

[0158] Example 1: Unlike traditional fixed base stations, due to the mobility of the WAB node, the parameters configured for the WAB node by the OAM can change according to the specific location of the WAB node, and the WAB node needs to manage the NG connection according to the current location of the WAB node (for example, perform appropriate NG establishment, release or update, etc.). This example illustrates how the WAB node establishes an NG connection with a suitable AMF during movement and how to trigger an NG handover to realize AMF relocation of the UE in the WAB scenario.

[0159] The Cell ID / TAC broadcast by the WAB-gNB and the AMF address connected by the WAB-gNB through the NG interface are configured by the OAM according to the location of the WAB node. Based on the current location of the WAB node, the OAM configures the TAC, Cell ID and AMF corresponding to the current location of the WAB node for the WAB node. If the WAB node has not established an NG connection with the AMF corresponding to the current location of the WAB node, the WAB node triggers the establishment of an NG connection with the AMF corresponding to the current location of the WAB node. The WAB node sends an NG Setup Request message to the AMF corresponding to the current location of the WAB node, and the Supported TA List in the NG Setup Request message contains the TAC served by the WAB node corresponding to the current location of the WAB node, and sets the GlobalRAN Node ID in the NG Setup Request message to the gNB-ID corresponding to the current location of the WAB node. If the WAB node moves to a new location, the OAM may update different parameters, and there are the following three cases: 1) AMF update

[0160] The WAB-gNB needs to establish an NG connection with the new AMF.

[0161] 2) AMF unchanged, TAC update

[0162] The WAB-gNB indicates the new TAC to the AMF through the Supported TA List in the wireless access network configuration update message sent to the AMF (the Supported TA List in the wireless access network configuration update message contains the TAC corresponding to the current location of the WAB node).

[0163] 3) AMF unchanged, gNB ID update contained in Cell ID

[0164] The WAB-gNB needs to establish an NG connection with the AMF with the new gNB ID. The WAB-gNB indicates the new gNB ID to the AMF through the Global RAN Node ID in the wireless access network configuration update message sent to the AMF (set the Global RAN Node ID in the wireless access network configuration update message to the gNB ID corresponding to the current location of the WAB node).

[0165] According to the current location of the WAB node, after the WAB node establishes an NG connection with the AMF corresponding to the current location of the WAB node, if the AMF to which the WAB node is connected does not belong to the AMF corresponding to the current location of the WAB node configured by the OAM, the WAB node needs to release or suspend the NG connection with the AMF. Therefore, the UE under the WAB node needs to be served by the AMF corresponding to the current location of the WAB node, and the WAB node triggers an NG handover for the UE.

[0166] Alternatively, the OAM configures the WAB node to establish an NG connection with the new AMF, or configures the WAB node to release the NG connection with the connected AMF, and the WAB node triggers an NG handover for the served UE.

[0167] For example, in the case where the WAB-gNB can only connect to one AMF, if the OAM configures a new AMF based on the current location of the WAB node, the WAB-gNB should release the NG connection with the original AMF. After the WAB-gNB establishes an NG connection with the target AMF according to the indication of the OAM, the WAB-gNB initiates an NG handover for the UE.

[0168] For another example, in the case where the WAB-gNB can connect to multiple AMFs at the same time, if the OAM instructs the WAB-gNB to release the NG connection with one or more AMFs currently connected based on the current location of the WAB node, if there is a UE served by the WAB node connected to these AMFs, the WAB node initiates an NG handover for these UEs to connect to other AMFs of the WAB node.

[0169] Example 2: This example illustrates how to select the target AMF in the case of UE AMF relocation with NG handover implementation in WAB scenario and NTN scenario.

[0170] 1) WAB scenario

[0171] According to example 1, when the AMF to which the WAB node has connected does not belong to the AMF corresponding to the current location of the WAB node configured by the OAM, or the OAM indicates (or configures) the WAB node to release the NG connection with a specific AMF, the WAB node needs to release the NG connection with these AMFs. The WAB node initiates NG handover for the UE to these AMFs.

[0172] The WAB node determines the TA identity corresponding to the current location of the WAB node, or determines the AMF identity corresponding to the current location of the WAB node. In order to select the AMF corresponding to the current location of the WAB node for the UE, the WAB node sets the Selected TAI field in the Target ID in the Handover Required message sent to the source AMF to the TAI corresponding to the current location of the WAB node, or adds the AMF identity corresponding to the current location of the WAB node in the Handover Required message, and sets the Global RAN Node ID field in the Target ID to the gNB ID corresponding to the current location of the WAB node. In this way, after the source AMF receives the Handover Required message, it can determine the target AMF according to the Selected TAI contained in the message, and then send a Namf_Communication_CreateUEContext Request (create UE context request) to the target AMF, which contains the Target ID in the Handover Required message. The target AMF establishes a context for the UE and allocates resources, and determines that the WAB node is the target node of the UE handover according to the Global RAN Node ID in the Target ID, and thus the target AMF sends a Handover Request message to the WAB node.

[0173] After the WAB node receives the Handover Request message, it generates a HandoverCommand (handover command) RRC message sent to the UE and sends the handover command to the target AMF in a Handover Request Acknowledge (handover request acknowledgement) message. The handover command is forwarded to the source AMF by the target AMF, and finally sent to the UE by the WAB node through an RRC reconfiguration message, the process is as followsFigure 6 as shown.

[0174] 2) NTN scenarios

[0175] When the NTN base station detects that the UE moves to a new location, if the AMF to which the UE is connected is not responsible for serving the current location area of the UE, the NTN base station initiates NG handover for the UE to the current AMF (source AMF) of the UE.

[0176] The NTN base station determines the TA identity corresponding to the current location of the UE, or determines the AMF responsible for the current location area of the UE. In order to select an AMF corresponding to the location area of the UE for the UE, the NTN base station sets the Selected TAI field in the Target ID in the Handover Required message sent to the source AMF to the TAI corresponding to the current location of the UE, or adds the AMF identifier corresponding to the current location of the UE in the Handover Required message, and sets the Global RAN Node ID field in the Target ID to the gNB ID of the NTN base station. In this way, after the source AMF receives the Handover Required message, it can determine the target AMF according to the Selected TAI or target AMF identifier contained in the message, and then send a Namf_Communication_CreateUEContext Request (create UE context request) to the target AMF, which contains the Target ID in the Handover Required message. The target AMF establishes a context for the UE and allocates resources, determines that the NTN base station is the target node of the UE handover according to the Global RAN Node ID in the Target ID, and thus sends a Handover Request message to the NTN base station.

[0177] The NTN base station determines that the UE performs intra-satellite cell handover according to the source cell identifier contained in the Handover Request message, establishes a context for the UE and allocates resources, generates a HandoverCommand (handover command) RRC message sent to the UE, and sends the handover command to the target AMF in a Handover Request Acknowledge (handover request acknowledgement) message. The handover command is forwarded by the target AMF to the source AMF, and finally sent to the UE by the NTN base station. The process is as shown in Figure 7 , Figure 7 corresponds to the NTN scenario as shown in Figure 3 , Figure 7 corresponds to the NTN scenario as shown in Figure 4 .

[0178] Example 3: This example illustrates how the WAB node selects the target cell for UE handover and selects the beam for RACH-less HO in the target cell in the absence of measurement reports in the process of AMF relocation of UE using NG handover in the WAB scenario.

[0179] The WAB node needs to connect to a new AMF because it moves to a new location area, at this time the TAC and Cell ID (including PCI and NCGI) broadcast by each serving cell of the WAB node also need to be changed. The WAB node needs to initiate NG handover to transfer the context of the UE to the new AMF, and at the same time the UE switches from the cell (i.e. the first cell) broadcasting the old Cell ID to the cell (i.e. the second cell) broadcasting the new Cell ID. According to Example 2, when the WAB node triggers NG handover in the WAB scenario, the UE may not have measured the cell broadcasting the new Cell ID, and cannot determine to switch the UE to the cell broadcasting the new Cell ID according to the measurement results.

[0180] During the movement of the WAB node, the UE is always served by the WAB node, and the cell identity broadcast by the WAB-gNB serving cell changes from the old Cell ID to the new Cell ID, but the signal quality measured by the UE for the WAB-gNB serving cell does not change. It can be understood that the measurement results of the UE for the cell broadcasting the old Cell ID are equivalent to the measurement results of the UE for the cell broadcasting the new Cell ID, or the cell broadcasting the new Cell ID is co-located with the cell broadcasting the old Cell ID for the UE. Therefore, there are the following methods to determine the target cell of the UE and the beam for RACH-less HO in the target cell.

[0181] Method one: when sending the NG handover required (Handover Required) message, the WAB node takes the measurement results of the UE for the cell broadcasting the old Cell ID as the measurement results of the UE for the co-located cell broadcasting the new Cell ID, and includes the measurement results of the cell broadcasting the new Cell ID in the HandoverPreparationInformation.

[0182] According to the conventional handover, the source access network node transmits an RRC container HandoverPreparationInformation when sending Handover Required to the source AMF, and the HandoverPreparationInformation contains the measurement results of candidate cells candidateCellInfoList.

[0183] The WAB node includes the measurement results of the cell broadcasting old Cell ID by the UE as the measurement results of the cell broadcasting new Cell ID by the UE in the candidateCellInfoList of HandoverPreparationInformation. In this way, the WAB node can determine to hand over the UE to the cell broadcasting new Cell ID based on the measurement results of the cell broadcasting new Cell ID included in the candidateCellInfoList after receiving the Handover Request message sent by the target AMF.

[0184] In order to select the beam for RACH-less HO in the cell broadcasting new Cell ID, the WAB node can also include the beam measurement results of the cell broadcasting old Cell ID by the UE as the beam measurement results of the co-sited cell broadcasting new Cell ID in the candidateCellInfoList. In this way, the RACH-less HO beam can be determined according to the beam measurement results of the cell broadcasting new Cell ID by the UE.

[0185] Method two: When receiving the NG handover request (Handover Request) message, the WAB node determines the target cell according to the old Cell ID carried by HandoverPreparationInformation and the co-sited relationship between the cell broadcasting old Cell ID and the cell broadcasting new Cell ID.

[0186] The HandoverPreparationInformation carries the information of the source cell, including the System Information Block (SIB) 1 of the source cell, which contains the cell identification information (including PCI and NCGI). The WAB node learns that the UE is served by the cell broadcasting the old Cell ID through the source cell information carried by the HandoverPreparationInformation, and then determines that the UE needs to be handed over to the cell broadcasting the new Cell ID according to the colocation relationship between the cell broadcasting the old Cell ID and the cell broadcasting the new Cell ID.

[0187] The source cell information carried by the HandoverPreparationInformation also includes the Cell Radio Network Temporary Identity (C-RNTI) used by the UE in the source cell, so the WAB node can also obtain the measurement result of the UE on the cell broadcasting the old Cell ID according to the source cell information carried by the HandoverPreparationInformation, and then take the measurement result of the UE on the cell broadcasting the old Cell ID as the measurement result of the UE on the cell broadcasting the new Cell ID.

[0188] In order to select the beam for RACH-less HO in the cell broadcasting the new Cell ID, the WAB node can also obtain the beam measurement result of the UE on the cell broadcasting the old Cell ID, and take the beam measurement result of the UE on the cell broadcasting the old Cell ID as the beam measurement result on the cell broadcasting the new Cell ID. For example, Figure 8 If the SSB#a beam in the first cell (the cell broadcasting the old Cell ID) and the SSB#b beam in the second cell (the cell broadcasting the new Cell ID) have a colocation relationship, the measurement result of the SSB#a beam in the first cell is taken as the measurement result of the SSB#b beam in the second cell, so that the RACH-less HO beam can be determined according to the measurement result of the UE on the beam of the first cell. Alternatively, the WAB node can directly select the beam in the second cell that has a colocation relationship with the beam used by the UE in the first cell for RACH-less HO. For example, as shown in Figure 8 If the UE uses the SSB#a beam in the first cell, it can be determined that the UE uses the SSB#b beam that is collocated with the SSB#a beam for RACH-less HO.

[0189] Figure 9 This is a schematic diagram of the structure of the access network device provided in the embodiments of this application, such as... Figure 9 As shown, the access network device includes a memory 920, a transceiver 910, and a processor 900; wherein the processor 900 and the memory 920 can also be physically arranged separately.

[0190] The memory 920 is used to store computer programs; the transceiver 910 is used to send and receive data under the control of the processor 900.

[0191] Among them, Figure 9 In this application, the bus architecture can include any number of interconnected buses and bridges, specifically linking various circuits of one or more processors represented by processor 900 and memory represented by memory 920 together. The bus architecture can also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be further described herein. The bus interface provides an interface. The transceiver 910 can be multiple elements, including a transmitter and a receiver, providing a unit for communicating with various other devices over a transmission medium, including wireless channels, wired channels, optical fibers, and other transmission media.

[0192] The processor 900 is responsible for managing the bus architecture and general processing, while the memory 920 can store the data used by the processor 900 during operation.

[0193] The processor 900 can be a central processing unit (CPU), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a complex programmable logic device (CPLD). The processor can also adopt a multi-core architecture.

[0194] The processor 900 executes any of the methods described in the embodiments of this application by calling a computer program stored in the memory 920 in accordance with the obtained executable instructions.

[0195] It should be noted that the access network device provided in this application embodiment can implement all the method steps implemented in the above method embodiment and can achieve the same technical effect. Here, the parts that are the same as those in the method embodiment and the beneficial effects will not be described in detail.

[0196] The switching device provided by the embodiments of the present application is described below. The switching device described below can be referred to the switching method described above.

[0197] Figure 10 A structural schematic diagram of the switching device provided by the embodiments of the present application is shown in FIG. 10. As shown in FIG. 10, the device includes a determination unit 1010 and a switching unit 1020. Figure 10

[0198] The determination unit 1010 is configured to determine that the terminal served by the access network device needs to reselect an access and mobility management function (AMF) according to one or more of the following: a current location of the access network device, a current location of the terminal served by the access network device, and configuration information of an operation administration and maintenance (OAM).

[0199] The switching unit 1020 is configured to initiate an NG handover for the terminal to a first AMF, where the first AMF is an AMF serving the terminal.

[0200] In some embodiments, the determination that the terminal served by the access network device needs to reselect an access and mobility management function (AMF) according to one or more of the following: a current location of the access network device, a current location of the terminal served by the access network device, and configuration information of an operation administration and maintenance (OAM) includes: In some embodiments, the determination that the terminal served by the access network device needs to reselect an AMF is based on one or more of the following: The OAM configures a second AMF for the current location of the access network device; According to the configuration information of the OAM, it is determined that the current location of the access network device corresponds to the second AMF; The OAM configures to release or suspend the NG connection between the access network device and the first AMF; According to the configuration information of the OAM, it is determined that the current location of the terminal corresponds to the second AMF; The second AMF is different from the first AMF.

[0201] In some embodiments, the device further includes a first sending unit configured to: send, to the second AMF, an NG setup request message containing a tracking area (TA) identifier of the access network device served by the access network device corresponding to the current location of the access network device and a base station identifier corresponding to the current location of the access network device; or

[0202] send, to the second AMF, a first radio access network configuration update message containing the TA identifier of the access network device served by the access network device corresponding to the current location of the access network device and / or the base station identifier corresponding to the current location of the access network device.

[0203] ​In some embodiments, the NG handover for the terminal is further used to change a serving AMF of the terminal from the first AMF to a second AMF.

[0204] In some embodiments, the NG handover for the terminal is further used to hand over the terminal in a first cell; wherein the first cell is a serving cell of the terminal.

[0205] In some embodiments, the apparatus further includes a second sending unit configured to: send, to the first AMF, a first NG handover request message, the first NG handover request message containing a TA identifier corresponding to a current location of the terminal or an AMF identifier corresponding to the current location of the terminal.

[0206] In some embodiments, the NG handover for the terminal is further used to hand over the terminal from a first cell to a second cell; wherein the first cell is a serving cell of the terminal, and the second cell is a cell served by an access network device corresponding to a current location of the access network device and configured by the OAM.

[0207] In some embodiments, the apparatus further includes a third sending unit configured to: send, to the first AMF, a second NG handover request message, the second NG handover request message containing a TA identifier of a cell served by an access network device corresponding to a current location of the access network device or an AMF identifier corresponding to the current location of the access network device.

[0208] In some embodiments, the apparatus further includes a first processing unit configured to: use a measurement result of the terminal measuring a first cell as a measurement result of the terminal measuring a second cell, wherein the first cell and the second cell have a co-location relationship or a corresponding relationship; include the measurement result of the second cell in the NG handover request message.

[0209] In some embodiments, the measurement result includes a beam measurement result.

[0210] In some embodiments, the apparatus further includes a second processing unit configured to: receive an NG handover request message sent by the second AMF, the NG handover request message containing a cell identifier of the first cell; determine, according to the co-location relationship or the corresponding relationship between the first cell and the second cell, that the target cell of the NG handover is the second cell.

[0211] In some embodiments, the apparatus further includes a third processing unit configured to: use a beam measurement result of the first cell as a beam measurement result of the second cell, and determine a beam used for handover based on the beam measurement result of the second cell; or

[0212] determine the beam for the handover according to a first beam used by the terminal in the first cell.

[0213] In some embodiments, the apparatus further includes a broadcasting unit configured to: broadcast a TA identity and a cell identity corresponding to the second cell.

[0214] In some embodiments, the apparatus further includes a fourth processing unit configured to: release the NG connection with the first AMF, or suspend the NG connection with the first AMF.

[0215] In some embodiments, the fourth processing unit is further configured to: in a case where the NG connection with the first AMF is suspended, not select the first AMF as an AMF serving the terminal, or not broadcast a paging message received from the first AMF.

[0216] In some embodiments, suspending the NG connection with the first AMF includes: sending an NG connection suspension request to the first AMF; or

[0217] sending a second radio access network configuration update message to the first AMF, the second radio access network configuration update message containing a TA identity of a TA served by the access network device corresponding to a current location of the access network device.

[0218] In some embodiments, the fourth processing unit is further configured to: maintain a stream control transmission protocol (SCTP) connection with the first AMF.

[0219] It should be noted that the above-mentioned switching apparatus provided by the embodiments of the present application can realize all the method steps realized by the above-mentioned method embodiments, and can achieve the same technical effects. Therefore, the same parts and beneficial effects of the method embodiments will not be described in detail.

[0220] It should be noted that the division of units in the embodiments of the present application is illustrative, and is only a logical function division. In actual implementation, another division mode can be used. In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0221] The integrated unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a processor-readable storage medium. Based on such an understanding, the technical solutions of the present application, essentially or in other words, the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (processor) to perform all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0222] In another aspect, the embodiments of the present application also provide a processor-readable storage medium, which stores a program for causing a processor to execute the switching method provided by the above-mentioned embodiments.

[0223] It should be noted that the processor-readable storage medium provided by the embodiments of the present application can implement all the method steps realized by the above-mentioned method embodiments, and can achieve the same technical effects. Therefore, the same parts and beneficial effects of the embodiments of the present application as the method embodiments will not be described in detail.

[0224] The processor-readable storage medium can be any available medium or data storage device that can be accessed by a processor, including but not limited to a magnetic memory (such as a floppy disk, a hard disk, a magnetic tape, a magneto-optical disk (MO), etc.), an optical memory (such as a CD, a DVD, a BD, a HVD, etc.), and a semiconductor memory (such as a ROM, an EPROM, an EEPROM, a non-volatile memory (NAND FLASH), a solid-state hard disk (SSD)), etc.

[0225] The technical solutions provided by the embodiments of the present application can be applied to various systems. For example, the applicable systems can be a long term evolution (LTE) system, an LTE frequency division duplex (FDD) system, an LTE time division duplex (TDD) system, a long term evolution advanced (LTE-A) system, a universal mobile system (UMTS), a worldwide interoperability for microwave access (WiMAX) system, a 5G New Radio (NR) system and its evolved communication system, a 6G (sixth generation mobile communication technology) system, and the like. The various systems can include terminal devices and network devices. The system can also include a core network part, such as an evolved packet system (EPC), a 5G core network (5GC), and the like.

[0226] The terminal referred to in embodiments of the present application can refer to a device that provides voice and / or data connectivity to a user, a handheld device having a wireless connection function, or other processing devices connected to a wireless modem, etc. In different systems, the name of the terminal can also be different, for example, in the 5G system, the terminal can be called a user equipment (UE). The wireless terminal device can communicate with one or more core networks (CN) through a radio access network (RAN), and the wireless terminal device can be a mobile terminal device, such as a mobile phone (or called "cellular" phone) and a computer with a mobile terminal device, for example, it can be a portable, pocket, handheld, computer built-in or vehicle-mounted mobile device, which exchanges language and / or data with the radio access network. For example, personal communication service (PCS) phones, cordless phones, session initiated protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), etc. The wireless terminal device can also be called a system, a subscriber unit, a subscriber station, a mobile station, a mobile, a remote station, an access point, a remote terminal, an access terminal, a user terminal, a user agent, a user device, which is not limited in embodiments of the present application.

[0227] The access network device according to embodiments of the present application can be a base station, which can include multiple cells serving terminals. The base station can also be referred to as an access point, or can be a device in an access network that communicates with wireless terminal devices over an air interface through one or more sectors, or other names, according to different application scenarios. The access network device can be used to exchange received air frames and Internet Protocol (IP) packets as a router between the wireless terminal device and the rest of the access network, which can include an Internet Protocol (IP) communication network. The access network device can also coordinate the management of the properties of the air interface. For example, the access network device according to embodiments of the present application can be a base transceiver station (BTS) in a global system for mobile communications (GSM) or a code division multiple access (CDMA) network, or can be a node B (NodeB) in a wide-band code division multiple access (WCDMA) network, or can be an evolved node B (eNB or e-NodeB) in a long term evolution (LTE) system, or a 5G base station (gNB) in a next generation system, or can be a home evolved node B (HeNB), a relay node, a femto, a pico, etc., which are not limited in embodiments of the present application. In some network structures, the access network device can include a centralized unit (CU) node and a distributed unit (DU) node, and the centralized unit and the distributed unit can also be arranged geographically apart.

[0228] Those skilled in the art should understand that embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, magnetic disk storage and optical storage, etc.) containing computer-usable program code.

[0229] The computer executable instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operations steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0230] These processor-executable instructions can also be stored in a processor-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the processor-readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0231] These processor-executable instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operations steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 Figure 1 one or more flow or blocks.

[0232] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A handover method, characterized by, The application is applied to an access network device, and comprises: determining that the terminal served by the access network device needs to reselect an access and mobility management function (AMF) according to one or more of the following: a current location of the access network device, a current location of the terminal served by the access network device, and configuration information of an operation administration and maintenance (OAM); initiating NG switching for the terminal to a first AMF; wherein the first AMF is an AMF serving the terminal.

2. The handover method of claim 1, wherein, The determining that the terminal served by the access network device needs to reselect an AMF according to one or more of the following: a current location of the access network device, a current location of the terminal served by the access network device, and configuration information of an OAM comprises: determining that the terminal served by the access network device needs to reselect an AMF in the case that one or more of the following conditions are met: the OAM configures a second AMF for the current location of the access network device; the OAM configures a second AMF for the current location of the access network device according to the configuration information of the OAM; the OAM configures to release or suspend the NG connection between the access network device and the first AMF; the OAM configures a second AMF for the current location of the terminal according to the configuration information of the OAM; wherein the second AMF is different from the first AMF.

3. The handover method of claim 2, wherein, The method further comprises: sending an NG setup request message to the second AMF, wherein the NG setup request message comprises a tracking area (TA) identity of the access network device serving the current location of the access network device and a base station identity corresponding to the current location of the access network device; or sending a first radio access network configuration update message to the second AMF, wherein the first radio access network configuration update message comprises the TA identity of the access network device serving the current location of the access network device and / or the base station identity corresponding to the current location of the access network device.

4. The handover method of claim 2, wherein, The NG switching for the terminal is used to change the AMF serving the terminal from the first AMF to the second AMF.

5. The handover method of claim 4, wherein, The NG switching for the terminal is further used to switch the terminal in a first cell; wherein the first cell is a serving cell of the terminal.

6. The handover method of claim 5, wherein, The method further comprises: sending a first NG switching requirement message to the first AMF, wherein the first NG switching requirement message comprises a TA identity corresponding to the current location of the terminal or an AMF identity corresponding to the current location of the terminal.

7. The handover method of claim 4, wherein, The NG switching for the terminal is further used to switch the terminal from a first cell to a second cell; wherein the first cell is a serving cell of the terminal, and the second cell is a cell serving the access network device and corresponding to the current location of the access network device, which is configured by the OAM.

8. The handover method of claim 7, wherein, The method further comprises: sending a second NG switching requirement message to the first AMF, wherein the second NG switching requirement message comprises a TA identity of the access network device serving the current location of the access network device or an AMF identity corresponding to the current location of the access network device.

9. The handover method of claim 7, wherein, The method further includes: The terminal measures a measurement result of the first cell as a measurement result of the second cell, wherein the first cell has a co-location relationship or a correspondence relationship with the second cell; The measurement result of the second cell is included in the NG handover request message.

10. The handover method of claim 9, wherein, The measurement result includes a beam measurement result.

11. The handover method of claim 7, wherein, The method further includes: receiving an NG handover request message sent by the second AMF, the NG handover request message containing a cell identifier of the first cell; According to the co-location relationship or the correspondence relationship between the first cell and the second cell, determining that the target cell of the NG handover is the second cell.

12. The handover method of claim 11, wherein, The method further includes: The beam measurement result of the first cell is used as the beam measurement result of the second cell, and the beam used for handover is determined based on the beam measurement result of the second cell; or The beam used for handover is determined according to the first beam used by the terminal in the first cell.

13. The handover method according to any one of claims 7 to 12, characterized by, The method further includes: Broadcasting the TA identifier and the cell identifier corresponding to the second cell.

14. The handover method of claim 1, wherein, The method further includes: Releasing the NG connection with the first AMF, or suspending the NG connection with the first AMF.

15. The handover method of claim 14, wherein, The method further includes: In the case of suspending the NG connection with the first AMF, not selecting the first AMF as an AMF serving the terminal, or not broadcasting a paging message received from the first AMF.

16. The handover method of claim 14, wherein, The suspension of the NG connection with the first AMF includes: Sending an NG connection suspension request to the first AMF; or Sending a second radio access network configuration update message to the first AMF, the second radio access network configuration update message containing a TA identifier of the access network device serving the current location of the access network device.

17. The handover method of claim 14, wherein, The method further includes: Maintaining a stream control transmission protocol (SCTP) connection with the first AMF.

18. An access network device, comprising: It includes a memory, a transceiver, a processor; The memory is used to store computer programs; the transceiver is used to transceive data under the control of the processor; The processor is used to read the computer programs in the memory and perform the following operations: According to one or more of the current location of the access network device, the current location of the terminal served by the access network device, and the configuration information of the operation management and maintenance (OAM), it is determined that the terminal served by the access network device needs to reselect an access and mobility management function (AMF); Initiating an NG handover for the terminal to the first AMF, wherein the first AMF is an AMF serving the terminal.

19. The access network device of claim 18, wherein, The determination that the terminal served by the access network device needs to reselect an AMF according to one or more of the current location of the access network device, the current location of the terminal served by the access network device, and the configuration information of the operation management and maintenance (OAM) includes: In the case that one or more of the following conditions is met, it is determined that the terminal served by the access network device needs to reselect an AMF: The OAM configures a second AMF for the current location of the access network device; determining, according to configuration information of the OAM, that the current location of the access network device corresponds to a second AMF; the OAM configuring to release or suspend the NG connection between the access network device and the first AMF; determining, according to configuration information of the OAM, that the current location of the terminal corresponds to a second AMF; wherein the second AMF is different from the first AMF.

20. The access network device of claim 19, wherein, The operations further include: sending, to the second AMF, an NG setup request message containing a tracking area (TA) identity of a cell served by the access network device corresponding to the current location of the access network device, and a base station identity corresponding to the current location of the access network device; or sending, to the second AMF, a first radio access network configuration update message containing the TA identity of the cell served by the access network device corresponding to the current location of the access network device, and / or the base station identity corresponding to the current location of the access network device.

21. The access network device of claim 19, wherein, The NG handover for the terminal is used to change an AMF serving the terminal from the first AMF to the second AMF.

22. The access network device of claim 21, wherein, The NG handover for the terminal is further used to hand over the terminal in a first cell; wherein the first cell is a serving cell of the terminal.

23. The access network device of claim 22, wherein, The operations further include: sending, to the first AMF, a first NG handover request message containing a TA identity corresponding to the current location of the terminal or an AMF identity corresponding to the current location of the terminal.

24. The access network device of claim 21, wherein, The NG handover for the terminal is further used to hand over the terminal from a first cell to a second cell; wherein the first cell is a serving cell of the terminal, and the second cell is a cell served by the access network device corresponding to the current location of the access network device and configured by the OAM.

25. The access network device of claim 24, wherein, The operations further include: sending, to the first AMF, a second NG handover request message containing a TA identity of a cell served by the access network device corresponding to the current location of the access network device, or an AMF identity corresponding to the current location of the access network device.

26. The access network device of claim 24, wherein, The operations further include: using a measurement result of the first cell measured by the terminal as a measurement result of the second cell, wherein the first cell has a co-sited relationship or a corresponding relationship with the second cell; including the measurement result of the second cell in an NG handover request message.

27. The access network device of claim 26, wherein, The measurement result includes a beam measurement result.

28. The access network device of claim 24, wherein, The operations further include: receiving an NG handover request message sent by the second AMF, the NG handover request message containing a cell identity of the first cell; determining, according to the co-sited relationship or the corresponding relationship between the first cell and the second cell, that the target cell of the NG handover is the second cell.

29. The access network device of claim 28, wherein, The operations further include: using a beam measurement result of the first cell as a beam measurement result of the second cell, and determining a beam used for handover based on the beam measurement result of the second cell; or determining a beam used for handover according to a first beam used by the terminal in the first cell.

30. The access network device of any of claims 24-29, wherein, The operations further include: broadcasting a TA identity and a cell identity corresponding to the second cell.

31. The access network device of claim 18, wherein, The operations further include: releasing the NG connection with the first AMF, or suspending the NG connection with the first AMF.

32. The access network device of claim 31, wherein, The operations further include: In the case of suspending the NG connection with the first AMF, the terminal is not selected as the AMF serving the terminal, or the paging message received from the first AMF is not broadcasted.

33. The access network device of claim 31, wherein, The suspending the NG connection with the first AMF includes: sending an NG connection suspension request to the first AMF; or sending a second radio access network configuration update message to the first AMF, the second radio access network configuration update message containing a TA identity of the access network device serving the current location of the access network device.

34. The access network device of claim 31, wherein, The operations further include: maintaining a stream control transmission protocol (SCTP) connection with the first AMF.

35. A switching device, characterized by comprise: a determining unit configured to determine, according to one or more of a current location of an access network device, a current location of a terminal served by the access network device, and configuration information of an operation administration and maintenance (OAM), that a terminal served by the access network device needs to reselect an access and mobility management function (AMF); a switching unit configured to initiate an NG handover for the terminal to a first AMF, the first AMF being an AMF serving the terminal.

36. A processor-readable storage medium, comprising: The processor readable storage medium stores a program for causing the processor to perform the method of any one of claims 1 to 17.

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