Handover method, access network device, apparatus, and storage medium

Abstract

Provided in the present disclosure are a handover method, an access network device, an apparatus, and a storage medium. The method comprises: an access network device determining the need for reselecting an access and mobility management function (AMF) for a terminal served by the access network device, according to one or more of the current position of the access network device, the current position of the terminal served by the access network device, and operation, administration, and maintenance (OAM) configuration information; initiating for the terminal an NG handover to a first AMF, wherein the first AMF is the AMF serving the terminal.

Description

Switching methods, access network equipment, devices and storage media

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410976163.7, filed on July 19, 2024, entitled “Switching Method, Access Network Equipment, Apparatus and Storage Medium”, which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to the field of wireless communication technology, and in particular to a handover method, access network equipment, apparatus, and storage medium. Background Technology

[0004] In both Wireless Access and Backhaul (WAB) and Non-Terrestrial Network (NTN) scenarios, for connected terminals (or User Equipment, UEs) served by WAB nodes or connected UEs served by satellite base stations, the NG handover process is used to relocate the UE's Access and Mobility Management Function (AMF), essentially changing the AMF of the serving UE. Traditionally, NG handover is triggered by the UE's measurements of the source and target cells. However, in WAB and NTN scenarios, the source and target Radio Access Network (RAN) nodes for UE handover are often the same network node, or even the same cell, making it impossible to trigger the NG handover preparation process based solely on the UE's measurements of the source and target cells. Summary of the Invention

[0005] This disclosure provides a handover method, access network equipment, apparatus, and storage medium to solve the problem of how to trigger NG handover to UE reselect AMF in WAB or NTN scenarios.

[0006] In a first aspect, this disclosure provides a handover method applied to access network equipment, comprising:

[0007] Based on 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 Operation, Management and Maintenance (OAM), determine whether the Access and Mobility Management Function (AMF) needs to be reselected for the terminal served by the access network device;

[0008] Initiate an NG handover for the terminal to the first AMF; where the first AMF is the AMF serving the terminal.

[0009] In some embodiments, determining whether a terminal serving the access network device needs to reselect an Access and Mobility Management Function (AMF) based on 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 method for managing and maintaining OAM, includes:

[0010] If one or more of the following conditions are met, it is determined that the terminal serving the access network equipment needs to reselect an AMF:

[0011] OAM configures a second AMF for the current location of the access network equipment;

[0012] Based on the OAM configuration information, determine the current location of the access network device corresponding to the second AMF;

[0013] OAM configuration releases or suspends the NG connection between the access network device and the first AMF;

[0014] Based on the OAM configuration information, determine the terminal's current location corresponding to the second AMF;

[0015] The second AMF is different from the first AMF.

[0016] In some embodiments, the method further includes:

[0017] Send an NG establishment request message to the second AMF. The NG establishment request message contains the Tracking Area (TA) identifier served by the access network device corresponding to the current location of the access network device, and the base station identifier corresponding to the current location of the access network device; or,

[0018] Send a first radio access network configuration update message to the second AMF. The first radio access network configuration update message includes the TA identifier of the access network device service 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.

[0019] In some embodiments, NG handover for a terminal is used to change the AMF of the serving terminal from a first AMF to a second AMF.

[0020] In some embodiments, NG handover for a terminal is further used to hand over the terminal within a first cell; wherein, the first cell is the serving cell of the terminal.

[0021] In some embodiments, the method further includes:

[0022] Send a first NG handover request message to the first AMF. The first NG handover request message contains the TA identifier corresponding to the current location of the terminal or the AMF identifier corresponding to the current location of the terminal.

[0023] In some embodiments, NG handover for a terminal is further used to hand over the terminal from the first cell to the second cell;

[0024] The first cell is the serving cell of the terminal, and the second cell is the cell served by the access network device configured by OAM and corresponding to the current location of the access network device.

[0025] In some embodiments, the method further includes:

[0026] Send a second NG handover request message to the first AMF. The second NG handover request message contains the TA identifier of the access network device service corresponding to the current location of the access network device, or the AMF identifier corresponding to the current location of the access network device.

[0027] In some embodiments, the method further includes:

[0028] The measurement results of the first cell measured by the terminal are used as the measurement results of the second cell measured by the terminal, wherein the first cell and the second cell have a co-location relationship or a corresponding relationship;

[0029] Include the measurement results of the second cell in the NG handover request message.

[0030] In some embodiments, the measurement results include beam measurement results.

[0031] In some embodiments, the method further includes:

[0032] Receive the NG handover request message sent by the second AMF, the NG handover request message containing the cell identifier of the first cell;

[0033] Based on the co-location relationship or correspondence between the first cell and the second cell, the target cell for NG handover is determined to be the second cell.

[0034] In some embodiments, the method further includes:

[0035] The beam measurement results of the first cell are used as the beam measurement results of the second cell, and the beam used for handover is determined based on the beam measurement results of the second cell; or,

[0036] The beam used for handover is determined based on the first beam used by the terminal in the first cell.

[0037] In some embodiments, the method further includes:

[0038] Broadcast the TA identifier and cell identifier corresponding to the second cell.

[0039] In some embodiments, the method further includes:

[0040] Release the NG connection with the first AMF, or suspend the NG connection with the first AMF.

[0041] In some embodiments, the method further includes:

[0042] If the NG connection with the first AMF is suspended, the first AMF is not selected as the AMF serving the terminal, or the paging message received from the first AMF is not broadcast.

[0043] In some embodiments, suspending the NG connection with the first AMF includes:

[0044] Send an NG connection suspend request to the first AMF; or...

[0045] Send a second radio access network configuration update message to the first AMF. The second radio access network configuration update message contains the TA identifier of the access network device service corresponding to the current location of the access network device.

[0046] In some embodiments, the method further includes:

[0047] Maintain the Stream Control Transport Protocol (SCTP) connection with the first AMF.

[0048] Secondly, this disclosure also provides an access network device, including a memory, a transceiver, and a processor;

[0049] A memory for storing computer programs; a transceiver for sending and receiving data under the control of the processor; and a processor for reading the computer programs from the memory and performing the following operations:

[0050] Based on 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 Operation, Management and Maintenance (OAM), determine whether the Access and Mobility Management Function (AMF) needs to be reselected for the terminal served by the access network device;

[0051] Initiate an NG handover for the terminal to the first AMF; where the first AMF is the AMF serving the terminal.

[0052] In some embodiments, determining whether a terminal serving the access network device needs to reselect an Access and Mobility Management Function (AMF) based on 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 Operation, Management and Maintenance (OAM), includes:

[0053] If one or more of the following conditions are met, it is determined that the terminal serving the access network equipment needs to reselect an AMF:

[0054] OAM configures a second AMF for the current location of the access network equipment;

[0055] Based on the OAM configuration information, determine the current location of the access network device corresponding to the second AMF;

[0056] OAM configuration releases or suspends the NG connection between the access network device and the first AMF;

[0057] Based on the OAM configuration information, determine the terminal's current location corresponding to the second AMF;

[0058] The second AMF is different from the first AMF.

[0059] In some embodiments, the operation further includes:

[0060] Send an NG establishment request message to the second AMF. The NG establishment request message contains the Tracking Area (TA) identifier served by the access network device corresponding to the current location of the access network device, and the base station identifier corresponding to the current location of the access network device; or,

[0061] Send a first radio access network configuration update message to the second AMF. The first radio access network configuration update message includes the TA identifier of the access network device service 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.

[0062] In some embodiments, NG handover for a terminal is used to change the AMF of the serving terminal from a first AMF to a second AMF.

[0063] In some embodiments, NG handover for a terminal is further used to hand over the terminal within a first cell; wherein, the first cell is the serving cell of the terminal.

[0064] In some embodiments, the operation further includes:

[0065] Send a first NG handover request message to the first AMF. The first NG handover request message contains the TA identifier corresponding to the current location of the terminal or the AMF identifier corresponding to the current location of the terminal.

[0066] In some embodiments, NG handover for a terminal is further used to hand over the terminal from the first cell to the second cell;

[0067] The first cell is the serving cell of the terminal, and the second cell is the cell served by the access network device configured by OAM and corresponding to the current location of the access network device.

[0068] In some embodiments, the operation further includes:

[0069] Send a second NG handover request message to the first AMF. The second NG handover request message contains the TA identifier of the access network device service corresponding to the current location of the access network device, or the AMF identifier corresponding to the current location of the access network device.

[0070] In some embodiments, the operation further includes:

[0071] The measurement results of the first cell measured by the terminal are used as the measurement results of the second cell measured by the terminal, wherein the first cell and the second cell have a co-location relationship or a corresponding relationship;

[0072] Include the measurement results of the second cell in the NG handover request message.

[0073] In some embodiments, the measurement results include beam measurement results.

[0074] In some embodiments, the operation further includes:

[0075] Receive the NG handover request message sent by the second AMF, the NG handover request message containing the cell identifier of the first cell;

[0076] Based on the co-location relationship or correspondence between the first cell and the second cell, the target cell for NG handover is determined to be the second cell.

[0077] In some embodiments, the operation further includes:

[0078] The beam measurement results of the first cell are used as the beam measurement results of the second cell, and the beam used for handover is determined based on the beam measurement results of the second cell; or,

[0079] The beam used for handover is determined based on the first beam used by the terminal in the first cell.

[0080] In some embodiments, the operation further includes:

[0081] Broadcast the TA identifier and cell identifier corresponding to the second cell.

[0082] In some embodiments, the operation further includes:

[0083] Release the NG connection with the first AMF, or suspend the NG connection with the first AMF.

[0084] In some embodiments, the operation further includes:

[0085] If the NG connection with the first AMF is suspended, the first AMF is not selected as the AMF serving the terminal, or the paging message received from the first AMF is not broadcast.

[0086] In some embodiments, suspending the NG connection with the first AMF includes:

[0087] Send an NG connection suspend request to the first AMF; or...

[0088] Send a second radio access network configuration update message to the first AMF. The second radio access network configuration update message contains the TA identifier of the access network device service corresponding to the current location of the access network device.

[0089] In some embodiments, the operation further includes:

[0090] Maintain the Stream Control Transport Protocol (SCTP) connection with the first AMF.

[0091] Thirdly, this disclosure also provides a switching device, comprising:

[0092] The determining unit is used to determine, based on 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 Operation, Management and Maintenance (OAM), that the terminal needs to reselect the Access and Mobility Management Function (AMF) for the terminal served by the access network device.

[0093] The handover unit is used to initiate an NG handover for the terminal to the first AMF; wherein the first AMF is the AMF of the serving terminal.

[0094] Fourthly, this disclosure also provides a non-transitory readable storage medium storing a program for causing a processor to execute the switching method described in the first aspect above.

[0095] Fifthly, this disclosure also provides a communication device that stores a program for causing the communication device to perform the switching method described in the first aspect above.

[0096] In a sixth aspect, this disclosure also provides a processor-readable storage medium storing a program for causing a processor to perform the switching method described in the first aspect above.

[0097] In a seventh aspect, this disclosure also provides a chip product that stores a program for causing the chip product to perform the switching method described in the first aspect above.

[0098] The handover method, access network device, apparatus, and storage medium disclosed herein allow the access network device to determine, based on one or more of the following: the current location of the access network device, the current location of the UE served by the access network device, and the OAM configuration information, that a new AMF needs to be selected for the UE serving the access network device. If it is determined that a new AMF needs to be selected for the UE, an NG handover is initiated for the UE to the first AMF. This eliminates the need to trigger the NG handover preparation process based on the UE's measurement results of the source and target cells, thus solving the problem of triggering NG handover to reselect an AMF for the UE in NTN or WAB scenarios. This provides the UE with better network services and improves the user experience. Attached Figure Description

[0099] To more clearly illustrate the technical solutions in the embodiments or related technologies of this disclosure, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0100] Figure 1 is a schematic diagram of the WAB structure provided by related technologies.

[0101] Figure 2 shows an example diagram of a WAB scenario provided by related technologies.

[0102] Figure 3 is one of the NTN scenario examples provided by related technologies.

[0103] Figure 4 is the second example of an NTN scenario provided by related technologies.

[0104] Figure 5 is a flowchart illustrating the switching method provided in an embodiment of this disclosure.

[0105] Figure 6 is an example diagram of the WAB scene NG switching process provided in the embodiments of this disclosure.

[0106] Figure 7 is an example diagram of the NG handover process in an NTN scenario provided in an embodiment of this disclosure.

[0107] Figure 8 is an example diagram of beam selection provided in an embodiment of this disclosure.

[0108] Figure 9 is a schematic diagram of the structure of the access network device provided in an embodiment of this disclosure.

[0109] Figure 10 is a schematic diagram of the switching device provided in an embodiment of this disclosure. Detailed Implementation

[0110] In this disclosure, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0111] In this disclosure, the term "multiple" refers to two or more, and other quantifiers are similar.

[0112] In the embodiments of this disclosure, the terms "first," "second," etc., are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of this disclosure can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first" and "second" are generally of the same class, and the number of objects is not limited; for example, the first object can be one or more.

[0113] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this disclosure.

[0114] To facilitate a clearer understanding of the technical solutions of the embodiments of this disclosure, some technical content related to the embodiments of this disclosure will be introduced first.

[0115] Figure 1 is a schematic diagram of the WAB structure provided by related technologies. As shown in Figure 1, the WAB node includes 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), enabling the WAB node to serve the UE. The WAB-MT has some UE functions and can access a RAN node (called the Backhaul Radio Access Network (BH-RAN) node) serving the WAB-MT and the 5G core network (called the Backhaul 5G Core Network (BH-5GC)) through the New Radio (NR) Uu interface. The Packet Data Unit (PDU) session established for the WAB-MT (called the Backhaul Packet Data Unit (BH PDU) session) can transmit the NG data packets (including UE services) of the WAB-gNB back to the core network. The WAB node supports local offloading, local services, and Mobile Edge Computing (MEC). Since WAB nodes support UE functions, they can be installed on airplanes, cruise ships, helicopters, and vehicles to provide 5G access for UEs. In Figure 1, NG-C and NG-U represent the NG control plane interface and NG user plane interface, respectively, and Xn-C and Xn-U represent the Xn control plane interface and Xn user plane interface, respectively.

[0116] In WAB scenarios, the configurations used by the WAB-gNB during UE service, such as the cell ID or tracking area code (TAC) broadcast by the WAB-gNB, and the AMF address connected to the WAB-gNB via the NG interface, are configured by the Operation Administration and Maintenance (OAM) based on the location of the WAB node. The WAB-MT can obtain the current geographical location of the 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. Then, the OAM configures the parameters of the WAB-gNB based on the location information of the WAB node.

[0117] Figure 2 shows an example diagram of a WAB scenario provided by related technologies, illustrating a scenario where an onboard WAB node serves a UE in a 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 remains within the control range of an AMF, the WAB node does not need to change the connected AMF or the broadcast TAC / Cell ID, as shown in scenario A of Figure 2. 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 broadcast TAC and Cell ID (including the Physical Cell ID (PCI) and NR Cell Global Identifier (NCGI)) also need to be changed, as shown in scenario B of Figure 2. When the TAC broadcast by the WAB node changes, UEs in Radio Resource Control (RRC) idle state and RRC inactive state can trigger a registration update process by reading the TAC, transferring the UE's context from the original AMF to the new AMF. At the same time, for UEs in RRC connected state, the serving AMF also needs to be changed from the original AMF to the new AMF.

[0118] In NTN scenarios, because a satellite has a wide coverage area, a satellite cell may simultaneously cover multiple geographic areas controlled by multiple AMFs, and the control areas of each AMF do not overlap. In this case, the satellite base station (or NTN base station) is connected to multiple AMFs simultaneously, and the cell broadcasts TAs corresponding to multiple AMFs at the same time, with each TA corresponding to a fixed geographic area. Because the TAC broadcast by the satellite cell remains unchanged, UEs in RRC idle state and RRC inactive state do not trigger registration updates when moving within the cell, and the AMF registered by the UE does not change. For UEs in RRC connected state, the satellite base station needs to ensure that the UE is connected to the AMF corresponding to the UE's current location. Figures 3 and 4 illustrate two different NTN scenarios. In the scenario shown in Figure 3, the base station function is jointly implemented by the ground gateway station and the satellite, and the ground gateway station is connected to multiple AMFs. In the scenario shown in Figure 4, the base station is located on the satellite (gNB on board), and the satellite base station is connected to multiple AMFs through multiple ground gateway stations.

[0119] In WAB and NTN scenarios, for connected UEs served by WAB nodes or satellite base stations, the NG handover process is used to relocate the UE's AMF, i.e., change the AMF of the serving UE. Traditionally, NG handover is triggered by the UE's measurements of the source and target cells. However, in WAB and NTN scenarios, the source and target RAN nodes for UE handover are actually the same network node, or even the same cell, making it impossible to trigger NG handover preparation based on the UE's measurements of the source and target cells. This disclosure provides a solution to this problem.

[0120] It should be noted that although the embodiments of this disclosure are illustrated using WAB and NTN scenarios (WAB nodes are characterized by small cell coverage, while NTN base stations are characterized by large cell coverage; the WAB scenario is used when the mobile base station coverage is small, and the NTN scenario is used when the mobile base station coverage is large), the technical solutions of this disclosure are not limited to these two scenarios. They can also be other scenarios with mobile access network devices that are well known to those skilled in the art or that may appear in the future. This disclosure does not limit them.

[0121] Figure 5 is a flowchart illustrating the handover method provided in this embodiment of the present disclosure. The method is applied to an access network device. As shown in Figure 5, the method includes the following steps 501 and 502.

[0122] Step 501: Based on 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 Operation, Management and Maintenance (OAM), determine the terminal that needs to reselect the Access and Mobility Management Function (AMF) for the access network device.

[0123] Specifically, this disclosure provides a handover method for AMF relocation, in which the access network device can determine the UE that needs to be served by the access network device to reselect the AMF based on one or more of the following: the current location of the access network device, the current location of the UE served by the access network device, and the OAM configuration information.

[0124] In some embodiments, the access network device may be a WAB node or an NTN base station.

[0125] For example, in a WAB scenario, a WAB node can determine which UE needs to reselect an AMF based on its current location and / or OAM configuration information. In other words, a change in the WAB node's location and / or OAM configuration information can trigger the WAB node to reselect an AMF for the UE.

[0126] For example, in an NTN scenario, the NTN base station can determine whether to reselect an AMF for the UE based on the UE's current location and / or OAM configuration information. In other words, a change in the UE's location and / or OAM configuration information can trigger the NTN base station to reselect an AMF for the UE.

[0127] Step 502: Initiate an NG handover for the terminal to the first AMF; where the first AMF is the AMF of the serving terminal.

[0128] Specifically, if the access network device determines that it needs to reselect an AMF for the UE, it can initiate an NG handover for the UE to the AMF of the currently serving UE (i.e., the first AMF, or the source AMF) to achieve AMF relocation for the UE. This disclosure does not limit the specific method by which the access network device initiates an NG handover for the terminal to the first AMF. For example, the access network device can send an NG handover request message to the first AMF to change the AMF of the serving UE; or, the access network device can initiate an NG handover for the terminal to the first AMF through other means besides sending an NG handover request message. This disclosure does not limit this approach.

[0129] The handover method provided in this disclosure allows the access network device to determine, based on one or more of the access network device's current location, the current location of the UE served by the access network device, and OAM configuration information, that a UE needs to reselect an AMF for the UE it serves. If it is determined that a new AMF needs to be selected for the UE, an NG handover is initiated for the UE to the first AMF. This eliminates the need to trigger an NG handover preparation process based on the UE's measurement results of the source and target cells, solving the problem of triggering NG handover for UE AMF reselection in NTN or WAB scenarios. This provides the UE with better network services and improves the user experience.

[0130] In some embodiments, determining whether an AMF needs to be reselected for a terminal serving the access network device based on 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 OAM configuration information, includes:

[0131] If one or more of the following conditions are met, it is determined that the terminal serving the access network equipment needs to reselect an AMF:

[0132] (1) OAM configures a second AMF for the current location of the access network device, wherein the second AMF is different from the first AMF.

[0133] For example, OAM configures a new AMF (second AMF) for the WAB node based on its current location. Since the second AMF is different from the first AMF, the WAB node determines in this case that the UE serving the WAB node needs to reselect an AMF. The WAB node can initiate an NG handover for the UE using the first AMF, changing the AMF serving the UE from the first AMF to the second AMF.

[0134] (2) The access network device determines the second AMF corresponding to its current location based on the OAM configuration information, wherein the second AMF is different from the first AMF.

[0135] For example, the OAM (Operating Management Advisor) configures corresponding AMFs (Advanced Feature Configurators) for different locations of the WAB (Web Application Board) node. Based on the OAM configuration information, the WAB node determines that the AMF corresponding to its current location is the second AMF. The WAB node then determines that it needs to connect to the second AMF. Since the second AMF is different from the first AMF, the WAB node in this case needs to reselect an AMF for the UE it serves. The WAB node can initiate an NG (Not Given) handover for the UE to the first AMF, changing the AMF serving the UE from the first AMF to the second AMF.

[0136] (3) OAM configuration releases or suspends the NG connection between the access network device and the first AMF.

[0137] For example, based on the current location of the WAB node, the OAM configuration causes the WAB node to release or suspend the NG connection with the first AMF. In this case, the WAB node determines that the UE serving the WAB node needs to reselect an AMF. The WAB node can initiate an NG handover for the UE to the first AMF, changing the AMF serving the UE from the first AMF to another AMF.

[0138] (4) Based on the configuration information of OAM, determine the current location of the terminal corresponding to the second AMF, wherein the second AMF is different from the first AMF.

[0139] For example, if the NTN base station detects that the UE has moved to a new location that is not within the service area of ​​the first AMF configured in the OAM but is within the service area of ​​the second AMF, the NTN base station determines that it needs to reselect an AMF for the UE. The NTN base station can initiate an NG handover for the UE to the first AMF, changing the AMF serving the UE from the first AMF to the second AMF.

[0140] In some embodiments, the method further includes:

[0141] Send an NG establishment request message to the second AMF. The NG establishment request message contains the TA identifier of the access network device serving the current location of the access network device, and the base station identifier corresponding to the current location of the access network device; or,

[0142] Send a first radio access network configuration update message to the second AMF. The first radio access network configuration update message includes the TA identifier of the access network device service 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.

[0143] Specifically, if the access network device determines that it needs to change the AMF of the serving UE 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 and send an NG Setup Request message to the second AMF. The NG Setup Request message contains the TA identifier (such as TAC) of the access network device service corresponding to the current location of the access network device, and the base station identifier (such as gNB ID) corresponding to the current location of the access network device.

[0144] In some embodiments, the access network device may include the TA identifier corresponding to the current location of the access network device in the Supported TA List in the NG Establishment Request message, and set the Global RAN Node ID in the NG Establishment Request message to the base station identifier corresponding to the current location of the access network device.

[0145] For example, if the second AMF is the AMF configured by OAM corresponding to the current location of the WAB node, and the WAB node has not yet established an NG connection with the second AMF, then the WAB node triggers the establishment of an NG connection with the second AMF. The WAB node 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.

[0146] 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 Radio Access Network Configuration Update message to the second AMF. The first Radio Access Network Configuration Update message includes the TA identifier of the access network device service 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, so as to update the TA identifier and / or base station identifier corresponding to the current location of the access network device.

[0147] In some embodiments, the access network device may include a TA identifier corresponding to the current location of the access network device in the Supported TA List of 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 base station identifier corresponding to the current location of the access network device.

[0148] For example, the second AMF is the AMF configured in the OAM that corresponds to the current location of the WAB node. The WAB node establishes an NG connection with the second AMF. The WAB node can update the TA identifier and / or base station identifier corresponding to its current location through the first radio access network configuration update message. The WAB node can include the TAC corresponding to its current location 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 its current location.

[0149] In some embodiments, NG handover for a terminal is further used to hand over the terminal within a first cell; wherein, the first cell is the serving cell of the terminal.

[0150] For example, in an NTN scenario, a satellite cell may simultaneously cover multiple geographical areas controlled by multiple AMFs. When the NTN base station determines that it needs to reselect an AMF for the UE, it initiates an NG handover for the UE. This NG handover is used to change the AMF serving the UE from the first AMF to the second AMF, but the UE's serving cell remains unchanged.

[0151] In some embodiments, the method further includes:

[0152] Send a first NG handover request message to the first AMF. The first NG handover request message contains the TA identifier corresponding to the current location of the terminal or the AMF identifier corresponding to the current location of the terminal.

[0153] Specifically, in order for the first AMF to select the second AMF corresponding to the current location of the UE as the target AMF, the access network device can send a first NG handover requirement message to the first AMF. The first NG handover requirement message contains 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, the first AMF can determine the target AMF based on the TA identifier or AMF identifier in the first NG handover requirement message.

[0154] In some embodiments, the access network device may set the Selected TAI field of the Target ID in the first NG handover request message to the TAI corresponding to the current location of the UE, or add an AMF identifier corresponding to the current location of the UE in the first NG handover request message.

[0155] For example, in an NTN scenario, in order for the first AMF to select the AMF corresponding to the UE's current location as the target AMF, the NTN base station can send a first NG handover request message to the first AMF, set the Selected TAI field of the Target ID in the first NG handover request message to the TAI corresponding to the UE's current location, or add the AMF identifier corresponding to the UE's current location to the first NG handover request message.

[0156] In some embodiments, NG handover for a terminal is further used to hand over the terminal from a first cell to a second cell; wherein, the first cell is the serving cell of the terminal, and the second cell is the cell served by the access network device configured by OAM corresponding to the current location of the access network device.

[0157] For example, in a WAB scenario, if a WAB node moves to a new location and determines that a UE serving that WAB node needs to reselect its AMF, the WAB node initiates an NG handover for the UE. This NG handover is used not only to change the AMF serving the UE from the first AMF to the second AMF, but also to switch the UE from the first cell to the second cell. That is, not only does the AMF serving the UE need to be changed, but the cell serving the UE also needs to be changed.

[0158] In some embodiments, the method further includes:

[0159] Send a second NG handover request message to the first AMF. The second NG handover request message contains the TA identifier of the access network device service corresponding to the current location of the access network device, or the AMF identifier corresponding to the current location of the access network device.

[0160] Specifically, in order for 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 requirement message to the first AMF. The second NG handover requirement message contains the TA identifier of the access network device service 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, the first AMF can determine the target AMF based on the TA identifier or AMF identifier in the second NG handover requirement message.

[0161] In some embodiments, the access network device may set the Selected TAI (Selected Tracking Area Identifier) ​​field of the Target ID in the second NG handover request message to the TAI corresponding to the current location of the access network device, or add an AMF identifier corresponding to the current location of the access network device to the second NG handover request message.

[0162] For example, in a WAB scenario, in order for 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 to the second NG handover request message.

[0163] In some embodiments, the method further includes:

[0164] The measurement results of the first cell measured by the terminal are used as the measurement results of the second cell measured by the terminal, wherein the first cell and the second cell have a co-location relationship or a corresponding relationship;

[0165] Include the measurement results of the second cell in the NG handover request message.

[0166] Specifically, the NG handover in this disclosure is not triggered by the UE's measurement results of the source cell and the target cell. Therefore, when the access network device initiates the NG handover, the UE may not have yet measured the second cell. This embodiment provides a solution 1 for how to select the target cell for UE handover when the measurement results of the second cell are missing: the access network device can use the measurement results of the UE measuring the first cell as the measurement results of the UE measuring the second cell, and include the measurement results of the second cell in the NG handover request message and send it to the first AMF.

[0167] For example, when a WAB node moves to a new location area and needs to connect to a new AMF, the TAC and cell identifier broadcast by each serving cell of the WAB node also need to be changed. The changed cell identifier is called the new Cell ID, and the original cell identifier is called the old Cell ID. The cell with the new Cell ID (i.e., the second cell) and the cell with the old Cell ID (i.e., the first cell) are co-located or have a one-to-one correspondence. During the WAB node's movement, the UE is always served by the WAB node. Therefore, although the cell identifier broadcast by the WAB node changes from the old Cell ID to the new Cell ID, the signal quality obtained by the UE when measuring the serving cell of the WAB node remains unchanged. Thus, the measurement result of the first cell can be used as the measurement result of the second cell.

[0168] According to the traditional NG handover, when the source access network node sends the NG handover request message to the source AMF, it transmits an RRC container HandoverPreparationInformation, which contains the measurement results of candidate cells (candidateCellInfoList).

[0169] In this embodiment, the WAB node can include the UE's measurement results for the first cell as the UE's measurement results for the second cell in the candidateCellInfoList of HandoverPreparationInformation. Thus, after receiving the NG handover request message from the target AMF, the WAB node can determine to hand over the UE to the second cell based on the measurement results for the second cell contained in the candidateCellInfoList.

[0170] In some embodiments, the measurement results include beam measurement results.

[0171] Specifically, in order to select the beam for handover, the access network device can use the beam measurement result of the UE measuring the first cell as the beam measurement result of the UE measuring the second cell, and include the beam measurement result of the second cell in the NG handover request message and send it to the first AMF.

[0172] For example, in a WAB scenario, when a UE switches from a first cell to a second cell using RACH-less HO (Rapid Access Without Handover), in order to select the beam for RACH-less HO, the WAB node can include the UE's beam measurement results for the first cell as the beam measurement results for the second cell in the candidateCellInfoList. The WAB node can then determine the beam for RACH-less HO based on the UE's beam measurement results for the second cell.

[0173] In some embodiments, the beam can be a Synchronization Signal and PBCH Block (SSB) beam or a Channel State Information-Reference Signal (CSI-RS) beam.

[0174] In some embodiments, the method further includes:

[0175] Receive the NG handover request message sent by the second AMF, the NG handover request message containing the cell identifier of the first cell;

[0176] Based on the co-location relationship or correspondence between the first cell and the second cell, the target cell for NG handover is determined to be the second cell.

[0177] Specifically, this embodiment provides a solution 2 for how to select the target cell for UE handover when the measurement results of the second cell are missing: the access network device can determine the target cell for NG handover as the second cell based on the co-location relationship or correspondence between the first cell and the second cell when the received NG handover request message contains the cell identifier of the first cell.

[0178] For example, when a WAB node receives an NG handover request message, the HandoverPreparationInformation in the NG handover request message carries information such as the cell identifier of the first cell and the UE's measurement results of the first cell. The WAB node learns that the UE is served by the first cell through the information of the first cell carried in the HandoverPreparationInformation. Then, based on the co-location relationship or correspondence between the first cell and the second cell, the WAB node can determine that the UE needs to be handed over to the second cell.

[0179] In some embodiments, the method further includes:

[0180] The beam measurement results of the first cell are used as the beam measurement results of the second cell, and the beam used for handover is determined based on the beam measurement results of the second cell; or,

[0181] The beam used for handover is determined based on the first beam used by the terminal in the first cell.

[0182] Specifically, in some embodiments, when the received NG handover request message contains the beam measurement results of the first cell, the access network device can use the beam measurement results of the first cell as the beam measurement results of the second cell (e.g., based on the co-location relationship or correspondence between the first cell and the second cell), and determine the beam for handover based on the beam measurement results of the second cell.

[0183] In some embodiments, the access network device can determine the beam for handover based on the first beam used by the terminal in the first cell. For example, the access network device can directly select a beam in a second cell that has a co-location relationship (or correspondence) 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 will use beam b in a second cell that has a co-location relationship (or correspondence) with beam a for RACH-less HO.

[0184] In some embodiments, the method further includes:

[0185] Broadcast the TA identifier and cell identifier corresponding to the second cell.

[0186] For example, if a WAB node moves to a new location area and needs to connect to a new AMF, the TA identifier and cell identifier broadcast by each serving cell of the WAB node also need to be changed. The second cell is the cell served by the WAB node corresponding to the current location of the WAB node, and the WAB node needs to broadcast the TA identifier and cell identifier corresponding to the second cell.

[0187] In some embodiments, the method further includes:

[0188] Release the NG connection with the first AMF, or suspend the NG connection with the first AMF.

[0189] Specifically, after the access network device changes the AMF serving the UE from the first AMF to another AMF, it can release the NG connection with the first AMF or suspend the NG connection with the first AMF.

[0190] In some embodiments, suspending the NG connection with the first AMF includes:

[0191] Send an NG connection suspend request to the first AMF; or...

[0192] Send a second radio access network configuration update message to the first AMF. The second radio access network configuration update message contains the TA identifier of the access network device service corresponding to the current location of the access network device.

[0193] Specifically, there are two different implementation methods for suspending the NG connection between the access network device and the first AMF.

[0194] 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.

[0195] Method 2: The access network device can implicitly indicate the suspension of 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 the TA identifier of the access network device service corresponding to the current location of the access network device, and the AMF corresponding to the TA identifier is not the first AMF, 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.

[0196] In some embodiments, the method further includes:

[0197] If the NG connection with the first AMF is suspended, the first AMF is not selected as the AMF serving the terminal, or the paging message received from the first AMF is not broadcast.

[0198] For example, if the access network device suspends the NG connection with the first AMF, the access network device will not select the first AMF as the AMF to serve the UE when establishing an RRC connection with the access network device.

[0199] For example, if the access network device suspends the NG connection with the first AMF, and the access network device receives a paging message from the first AMF, the access network device will not broadcast the paging message.

[0200] In some embodiments, if the access network device releases or suspends the NG connection with the first AMF, the access network device may still maintain the Stream Control Transmission Protocol (SCTP) connection with the first AMF.

[0201] The methods provided in the above embodiments of this disclosure are illustrated by specific examples below.

[0202] Example 1:

[0203] Unlike traditional fixed base stations, due to the mobility of WAB nodes, the parameters configured by OAM for WAB nodes can change according to the specific location of the WAB node. WAB nodes need to manage NG connections based on their current location (e.g., performing appropriate NG establishment, release, or update operations). This example illustrates how, in a WAB scenario, a WAB node establishes an NG connection with a suitable AMF during movement, and how to trigger NG handover to achieve AMF relocation for the UE.

[0204] The Cell ID / TAC broadcast by the WAB-gNB and the AMF address to which the WAB-gNB connects via the NG interface are configured by OAM based on the WAB node's location. Based on the WAB node's current location, OAM configures the TAC, Cell ID, and AMF corresponding to that location. If the WAB node has not yet established an NG connection with the AMF corresponding to its current location, the WAB node triggers the establishment of an NG connection. The WAB node sends an NG Setup Request message to the AMF corresponding to its current location. The Supported TA List in the NG Setup Request message includes the TACs served by the WAB node at its current location, and the Global RAN Node ID in the NG Setup Request message is set to the gNB-ID corresponding to the WAB node's current location. If the WAB node moves to a new location, OAM may update different parameters, in the following three cases:

[0205] 1) AMF Update

[0206] WAB-gNB needs to establish an NG connection with the new AMF.

[0207] 2) AMF remains unchanged, TAC is updated.

[0208] The WAB-gNB indicates the new TAC in the Supported TA List in the Radio Access Network Configuration Update message sent to the AMF (the Supported TA List in the Radio Access Network Configuration Update message contains the TAC corresponding to the current location of the WAB node).

[0209] 3) The AMF remains unchanged, but the gNB ID contained in the Cell ID is updated.

[0210] The WAB-gNB needs to establish an NG connection with the AMF using a new gNB ID. The WAB-gNB indicates the new gNB ID to the AMF through the Global RAN Node ID in the Radio Access Network Configuration Update message sent to the AMF (setting the Global RAN Node ID in the Radio Access Network Configuration Update message to the gNB ID corresponding to the current location of the WAB node).

[0211] Based on the current location of the WAB node, after the WAB node establishes an NG connection with the AMF corresponding to its current location, if the AMF already connected to the WAB node is not one of the AMFs configured in the OAM that corresponds to the current location of the WAB node, the WAB node needs to release or suspend the NG connection with the connected 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 at this time, the WAB node triggers an NG handover for the UE.

[0212] Alternatively, when the OAM configures the WAB node to establish an NG connection with a new AMF, or when the WAB node is configured to release the NG connection with an already connected AMF, the WAB node triggers an NG handover for the UE it serves.

[0213] For example, if a WAB-gNB can only connect to one AMF, and the OAM configures a new AMF based on the current location of the WAB node, the WAB-gNB should release its NG connection with the original AMF. After establishing an NG connection with the target AMF according to the OAM's instructions, the WAB-gNB initiates an NG handover for the UE.

[0214] For example, if a WAB-gNB can be connected to multiple AMFs simultaneously, and the OAM instructs the WAB-gNB to release the NG connection with one or more currently connected AMFs based on the current location of the WAB node, and if any UEs served by the WAB node are connected to these AMFs, the WAB node initiates an NG handover for these UEs, allowing these UEs to connect to other AMFs of the WAB node.

[0215] Example 2:

[0216] This example illustrates how to select the target AMF when using NG handover to achieve UE AMF relocation in both WAB and NTN scenarios.

[0217] 1) WAB scenario

[0218] According to Example 1, when the AMF connected to the WAB node does not belong to the AMF configured by the OAM corresponding to the current location of the WAB node, or when the OAM instructs (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 an NG handover for the UE to these AMFs.

[0219] The WAB node determines either the TA identifier corresponding to its current location or the AMF identifier corresponding to its current location. To select the AMF corresponding to the WAB node's current location for the UE, the WAB node sets the Selected TAI field of the Target ID in the Handover Required message sent to the source AMF to the TAI corresponding to its current location, or adds the AMF identifier corresponding to the WAB node's current location to the Handover Required message, while setting the Global RAN Node ID field in the Target ID to the gNB ID corresponding to the WAB node's current location. Upon receiving the Handover Required message, the source AMF can determine the target AMF based on the Selected TAI contained in the message, and then sends a Namf_Communication_CreateUEContext Request to the target AMF. This request includes the Target ID from the Handover Required message. The target AMF establishes the context for the UE and allocates resources. Based on the Global RAN Node ID in the Target ID, it determines that the WAB node is the target node for UE handover, and thus, the target AMF sends a Handover Request message to the WAB node.

[0220] After receiving the Handover Request message, the WAB node generates a HandoverCommand RRC message to be sent to the UE and includes the handover command in a Handover Request Acknowledge message, which is then sent to the target AMF. The target AMF forwards the handover command to the source AMF, and finally the WAB node sends it to the UE via an RRC reconfiguration message. This process is shown in Figure 6.

[0221] 2) NTN scenario

[0222] When the NTN base station detects that the UE has moved to a new location, if the AMF to which the UE is connected is not responsible for serving the UE's current location area, the NTN base station initiates an NG handover for the UE to the UE's current AMF (source AMF).

[0223] The NTN base station determines the TA identifier corresponding to the UE's current location, or determines the AMF responsible for the UE's current location area. To select an AMF corresponding to the UE's location area, the NTN base station sets the Selected TAI field of the Target ID in the Handover Required message sent to the source AMF to the TAI corresponding to the UE's current location, or adds the AMF identifier corresponding to the UE's current location to the Handover Required message and sets the Global RAN Node ID field of the Target ID to the NTN base station's gNB ID. Upon receiving the Handover Required message, the source AMF can determine the target AMF based on the Selected TAI or target AMF identifier contained in the message, and then sends a Namf_Communication_CreateUEContext Request to the target AMF. This request includes the Target ID from the Handover Required message. The target AMF establishes a context for the UE and allocates resources. Based on the Global RAN Node ID in the Target ID, it determines that the NTN base station is the target node for UE handover, and thus sends a Handover Request message to the NTN base station.

[0224] The NTN base station determines the UE's intra-cell handover based on the source cell identifier contained in the Handover Request message, establishes a context for the UE and allocates resources, generates a HandoverCommand RRC message to be sent to the UE, and includes this handover command in a Handover Request Acknowledge message sent to the target AMF. The target AMF forwards the handover command to the source AMF, and finally the NTN base station sends it to the UE. This process is shown in Figure 7, where (a) corresponds to the NTN scenario shown in Figure 3, and (b) corresponds to the NTN scenario shown in Figure 4.

[0225] Example 3:

[0226] This example illustrates how, in a WAB scenario, during the AMF relocation process of a UE using NG handover, the WAB node selects the target cell for UE handover in the absence of a measurement report, and selects the beam for RACH-less HO handover in the target cell.

[0227] Because the WAB node moves to a new location area, it needs to connect to a new AMF. At this time, the TAC and Cell ID (including PCI and NCGI) broadcast by the WAB node for each serving cell also need to be changed. The WAB node needs to initiate an NG handover, transferring the UE's context to the new AMF. Simultaneously, the UE switches from the cell broadcasting the old Cell ID (i.e., the first cell) to the cell broadcasting the new Cell ID (i.e., the second cell). According to Example 2, in a WAB scenario, when the WAB node triggers an NG handover, the UE may not have yet measured the cell broadcasting the new Cell ID, making it impossible to determine whether to switch the UE to the cell broadcasting the new Cell ID based on the measurement results.

[0228] During the WAB node's movement, the UE is always served by the WAB node. The cell identifier 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 from the WAB-gNB serving cell remains unchanged. This can be understood as the UE's measurement result for the cell broadcasting the old Cell ID being equivalent to the UE's measurement result for the cell broadcasting the new Cell ID, or that the cell broadcasting the new Cell ID and the cell broadcasting the old Cell ID are co-located for the UE. Therefore, the following method can be used to determine the UE's target cell and the beam for RACH-less HO in the target cell.

[0229] Method 1: When sending the NG Handover Required message, the WAB node uses the UE's measurement results for the cell broadcasting the old Cell ID as the UE's measurement results for the co-located cell broadcasting the new Cell ID, and includes the measurement results for the cell broadcasting the new Cell ID in the HandoverPreparationInformation.

[0230] According to the traditional handover, when the source access network node sends Handover Required to the source AMF, it transmits an RRC container HandoverPreparationInformation, which contains the measurement results of the candidate cells, candidateCellInfoList.

[0231] The WAB node includes the UE's measurement results for the cell broadcasting the old Cell ID as the UE's measurement results for the cell broadcasting the new Cell ID in the `candidateCellInfoList` of `HandoverPreparationInformation`. Thus, after receiving a Handover Request message from the target AMF, the WAB node can determine whether to switch the UE to the cell broadcasting the new Cell ID based on the measurement results for the cell broadcasting the new Cell ID contained in `candidateCellInfoList`.

[0232] To select the RACH-less HO beam in the cell broadcasting the new Cell ID, the WAB node can also include the UE's beam measurement results for the cell broadcasting the old Cell ID as the beam measurement results for the co-located cell broadcasting the new Cell ID in the candidateCellInfoList. This allows the RACH-less HO beam to be determined based on the UE's beam measurement results for the cell broadcasting the new Cell ID.

[0233] Method 2: When receiving an NG handover request message, the WAB node determines the target cell based on the old Cell ID carried in the HandoverPreparationInformation and the co-location relationship between the cell broadcasting the old Cell ID and the cell broadcasting the new Cell ID.

[0234] The HandoverPreparationInformation carries information about the source cell, including the source cell's System Information Block (SIB)1, which contains cell identification information (including PCI and NCGI). The WAB node uses the source cell information carried in the HandoverPreparationInformation to determine that the UE is served by the cell broadcasting the old Cell ID. Based on the co-location relationship between the cell broadcasting the old Cell ID and the cell broadcasting the new Cell ID, the WAB node can then determine whether the UE needs to be switched to the cell broadcasting the new Cell ID.

[0235] The source cell information carried by HandoverPreparationInformation also includes the Cell Radio Network Temporary Identity (C-RNTI) used by the UE in the source cell. Therefore, the WAB node can also obtain the UE's measurement results for the cell broadcasting the old Cell ID based on the source cell information carried by HandoverPreparationInformation, and then use the UE's measurement results for the cell broadcasting the old Cell ID as the UE's measurement results for the cell broadcasting the new Cell ID.

[0236] To select the beam for RACH-less HO in the cell broadcasting the new Cell ID, the WAB node can also obtain the UE's beam measurement results for the cell broadcasting the old Cell ID, and use these results as the beam measurement results for the cell broadcasting the new Cell ID. For example, in 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) are co-located, the measurement result of the SSB#a beam in the first cell is used as the measurement result of the SSB#b beam in the second cell. This allows the RACH-less HO beam to be determined based on the UE's beam measurement results in the first cell. Alternatively, the WAB node can directly select the beam in the second cell that is co-located 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, which is co-located with the SSB#a beam, for RACH-less HO.

[0237] Figure 9 is a schematic diagram of the structure of the access network device provided in the embodiment of this disclosure. As shown in Figure 9, 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.

[0238] 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.

[0239] In Figure 9, the bus architecture may 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. The bus architecture may 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. A bus interface provides an interface. Transceiver 910 may be multiple elements, including transmitters and receivers, providing a unit for communicating with various other devices over a transmission medium, including wireless channels, wired channels, optical fibers, and other transmission media.

[0240] 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.

[0241] 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.

[0242] The processor 900 executes any of the methods provided in the embodiments of this disclosure according to the obtained executable instructions by calling a computer program stored in the memory 920, including:

[0243] Based on 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 Operation, Management and Maintenance (OAM), determine whether the Access and Mobility Management Function (AMF) needs to be reselected for the terminal served by the access network device;

[0244] Initiate an NG handover for the terminal to the first AMF; where the first AMF is the AMF serving the terminal.

[0245] In some embodiments, determining whether a terminal serving the access network device needs to reselect an Access and Mobility Management Function (AMF) based on 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 method for managing and maintaining OAM, includes:

[0246] If one or more of the following conditions are met, it is determined that the terminal serving the access network equipment needs to reselect an AMF:

[0247] OAM configures a second AMF for the current location of the access network equipment;

[0248] Based on the OAM configuration information, determine the current location of the access network device corresponding to the second AMF;

[0249] OAM configuration releases or suspends the NG connection between the access network device and the first AMF;

[0250] Based on the OAM configuration information, determine the terminal's current location corresponding to the second AMF;

[0251] The second AMF is different from the first AMF.

[0252] In some embodiments, the method further includes:

[0253] Send an NG establishment request message to the second AMF. The NG establishment request message contains the Tracking Area (TA) identifier served by the access network device corresponding to the current location of the access network device, and the base station identifier corresponding to the current location of the access network device; or,

[0254] Send a first radio access network configuration update message to the second AMF. The first radio access network configuration update message includes the TA identifier of the access network device service 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.

[0255] In some embodiments, NG handover for a terminal is used to change the AMF of the serving terminal from a first AMF to a second AMF.

[0256] In some embodiments, NG handover for a terminal is further used to hand over the terminal within a first cell; wherein, the first cell is the serving cell of the terminal.

[0257] In some embodiments, the method further includes:

[0258] Send a first NG handover request message to the first AMF. The first NG handover request message contains the TA identifier corresponding to the current location of the terminal or the AMF identifier corresponding to the current location of the terminal.

[0259] In some embodiments, NG handover for a terminal is further used to hand over the terminal from the first cell to the second cell;

[0260] The first cell is the serving cell of the terminal, and the second cell is the cell served by the access network device configured by OAM and corresponding to the current location of the access network device.

[0261] In some embodiments, the method further includes:

[0262] Send a second NG handover request message to the first AMF. The second NG handover request message contains the TA identifier of the access network device service corresponding to the current location of the access network device, or the AMF identifier corresponding to the current location of the access network device.

[0263] In some embodiments, the method further includes:

[0264] The measurement results of the first cell measured by the terminal are used as the measurement results of the second cell measured by the terminal, wherein the first cell and the second cell have a co-location relationship or a corresponding relationship;

[0265] Include the measurement results of the second cell in the NG handover request message.

[0266] In some embodiments, the measurement results include beam measurement results.

[0267] In some embodiments, the method further includes:

[0268] Receive the NG handover request message sent by the second AMF, the NG handover request message containing the cell identifier of the first cell;

[0269] Based on the co-location relationship or correspondence between the first cell and the second cell, the target cell for NG handover is determined to be the second cell.

[0270] In some embodiments, the method further includes:

[0271] The beam measurement results of the first cell are used as the beam measurement results of the second cell, and the beam used for handover is determined based on the beam measurement results of the second cell; or,

[0272] The beam used for handover is determined based on the first beam used by the terminal in the first cell.

[0273] In some embodiments, the method further includes:

[0274] Broadcast the TA identifier and cell identifier corresponding to the second cell.

[0275] In some embodiments, the method further includes:

[0276] Release the NG connection with the first AMF, or suspend the NG connection with the first AMF.

[0277] In some embodiments, the method further includes:

[0278] If the NG connection with the first AMF is suspended, the first AMF is not selected as the AMF serving the terminal, or the paging message received from the first AMF is not broadcast.

[0279] In some embodiments, suspending the NG connection with the first AMF includes:

[0280] Send an NG connection suspend request to the first AMF; or...

[0281] Send a second radio access network configuration update message to the first AMF. The second radio access network configuration update message contains the TA identifier of the access network device service corresponding to the current location of the access network device.

[0282] In some embodiments, the method further includes:

[0283] Maintain the Stream Control Transport Protocol (SCTP) connection with the first AMF.

[0284] It should be noted that the access network device provided in this embodiment can implement all the method steps implemented in the above method embodiment and can achieve the same technical effect. Therefore, the parts and beneficial effects that are the same as those in the method embodiment will not be described in detail here.

[0285] The switching device provided in the embodiments of this disclosure is described below. The switching device described below can be referred to in correspondence with the switching method described above.

[0286] Figure 10 is a schematic diagram of the switching device provided in an embodiment of the present disclosure. As shown in Figure 10, the device includes a determining unit 1010 and a switching unit 1020.

[0287] The determining unit 1010 is used to determine, based on 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 Operation, Management and Maintenance (OAM), that the terminal needs to reselect the Access and Mobility Management Function (AMF) for the terminal served by the access network device.

[0288] The handover unit 1020 is used to initiate an NG handover for the terminal to the first AMF; wherein the first AMF is the AMF of the serving terminal.

[0289] In some embodiments, determining whether a terminal serving the access network device needs to reselect an Access and Mobility Management Function (AMF) based on 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 Device Management and Maintenance (OAM), includes:

[0290] If one or more of the following conditions are met, it is determined that the terminal serving the access network equipment needs to reselect an AMF:

[0291] OAM configures a second AMF for the current location of the access network equipment;

[0292] Based on the OAM configuration information, determine the current location of the access network device corresponding to the second AMF;

[0293] OAM configuration releases or suspends the NG connection between the access network device and the first AMF;

[0294] Based on the OAM configuration information, determine the terminal's current location corresponding to the second AMF;

[0295] The second AMF is different from the first AMF.

[0296] In some embodiments, the apparatus further includes a first transmitting unit for:

[0297] Send an NG establishment request message to the second AMF. The NG establishment request message contains the Tracking Area (TA) identifier served by the access network device corresponding to the current location of the access network device, and the base station identifier corresponding to the current location of the access network device; or,

[0298] Send a first radio access network configuration update message to the second AMF. The first radio access network configuration update message includes the TA identifier of the access network device service 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.

[0299] In some embodiments, NG handover for a terminal is used to change the AMF of the serving terminal from a first AMF to a second AMF.

[0300] In some embodiments, NG handover for a terminal is further used to hand over the terminal within a first cell; wherein, the first cell is the serving cell of the terminal.

[0301] In some embodiments, the apparatus further includes a second transmitting unit for:

[0302] Send a first NG handover request message to the first AMF. The first NG handover request message contains the TA identifier corresponding to the current location of the terminal or the AMF identifier corresponding to the current location of the terminal.

[0303] In some embodiments, NG handover for a terminal is further used to hand over the terminal from the first cell to the second cell;

[0304] The first cell is the serving cell of the terminal, and the second cell is the cell served by the access network device configured by OAM and corresponding to the current location of the access network device.

[0305] In some embodiments, the apparatus further includes a third transmitting unit, configured to:

[0306] Send a second NG handover request message to the first AMF. The second NG handover request message contains the TA identifier of the access network device service corresponding to the current location of the access network device, or the AMF identifier corresponding to the current location of the access network device.

[0307] In some embodiments, the apparatus further includes a first processing unit for:

[0308] The measurement results of the first cell measured by the terminal are used as the measurement results of the second cell measured by the terminal, wherein the first cell and the second cell have a co-location relationship or a corresponding relationship;

[0309] Include the measurement results of the second cell in the NG handover request message.

[0310] In some embodiments, the measurement results include beam measurement results.

[0311] In some embodiments, the device further includes a second processing unit for:

[0312] Receive the NG handover request message sent by the second AMF, the NG handover request message containing the cell identifier of the first cell;

[0313] Based on the co-location relationship or correspondence between the first cell and the second cell, the target cell for NG handover is determined to be the second cell.

[0314] In some embodiments, the apparatus further includes a third processing unit for:

[0315] The beam measurement results of the first cell are used as the beam measurement results of the second cell, and the beam used for handover is determined based on the beam measurement results of the second cell; or,

[0316] The beam used for handover is determined based on the first beam used by the terminal in the first cell.

[0317] In some embodiments, the apparatus further includes a broadcasting unit for:

[0318] Broadcast the TA identifier and cell identifier corresponding to the second cell.

[0319] In some embodiments, the device further includes a fourth processing unit for:

[0320] Release the NG connection with the first AMF, or suspend the NG connection with the first AMF.

[0321] In some embodiments, the fourth processing unit is further configured to:

[0322] If the NG connection with the first AMF is suspended, the first AMF is not selected as the AMF serving the terminal, or the paging message received from the first AMF is not broadcast.

[0323] In some embodiments, suspending the NG connection with the first AMF includes:

[0324] Send an NG connection suspend request to the first AMF; or...

[0325] Send a second radio access network configuration update message to the first AMF. The second radio access network configuration update message contains the TA identifier of the access network device service corresponding to the current location of the access network device.

[0326] In some embodiments, the fourth processing unit is further configured to:

[0327] Maintain the Stream Control Transport Protocol (SCTP) connection with the first AMF.

[0328] It should be noted that the switching device provided in this embodiment can implement all the method steps implemented in the above method embodiment and achieve the same technical effect. Therefore, the parts and beneficial effects that are the same as those in the method embodiment will not be described in detail here.

[0329] It should be noted that the division of units in the embodiments of this disclosure is illustrative and only represents one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional units in the various embodiments of this disclosure can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated units described above can be implemented in hardware or as software functional units.

[0330] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a processor-readable storage medium. Based on this understanding, the technical solution of this disclosure, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this disclosure. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0331] On the other hand, embodiments of this disclosure also provide a processor-readable storage medium storing a program for causing a processor to execute the switching methods provided in the above embodiments.

[0332] It should be noted that the processor-readable storage medium provided in this embodiment can implement all the method steps implemented in the above method embodiments and achieve the same technical effect. Therefore, the parts and beneficial effects that are the same as those in the method embodiments will not be described in detail here.

[0333] The processor-readable storage medium can be any available medium or data storage device that the processor can access, including but not limited to magnetic memory (e.g., floppy disk, hard disk, magnetic tape, magneto-optical disk (MO)), optical memory (e.g., CD, DVD, BD, HVD), and semiconductor memory (e.g., ROM, EPROM, EEPROM, non-volatile memory (NAND FLASH), solid-state drive (SSD)).

[0334] The technical solutions provided in this disclosure can be applied to a variety of systems. For example, applicable systems may include Long Term Evolution (LTE) systems, LTE Frequency Division Duplex (FDD) systems, LTE Time Division Duplex (TDD) systems, Long Term Evolution Advanced (LTE-A) systems, Universal Mobile Telecommunications System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) systems, 5G New Radio (NR) systems and their evolved communication systems, and 6G (sixth generation mobile communication technology) systems. These systems may include terminal equipment and network equipment. The systems may also include a core network component, such as the Evolved Packet Core (EPC) or the 5G Core Network (5GC).

[0335] The terminals disclosed in this embodiment can be devices that provide voice and / or data connectivity to users, handheld devices with wireless connectivity, or other processing devices connected to a wireless modem. The names of the terminals may differ in different systems; for example, in a 5G system, a terminal may be called User Equipment (UE). Wireless terminal devices can communicate with one or more core networks (CNs) via a Radio Access Network (RAN). Wireless terminal devices can be mobile terminal devices, such as mobile phones (or "cellular" phones) and computers with mobile terminal devices, for example, portable, pocket-sized, handheld, computer-embedded, or vehicle-mounted mobile devices that exchange voice and / or data with the RAN. Examples include Personal Communication Service (PCS) phones, cordless phones, Session Initiated Protocol (SIP) phones, Wireless Local Loop (WLL) stations, and Personal Digital Assistants (PDAs). Wireless terminal equipment can also be referred to as a system, subscriber unit, subscriber station, mobile station, mobile station, remote station, access point, remote terminal, access terminal, user terminal, user agent, or user device, but is not limited to these terms in the embodiments disclosed herein.

[0336] The access network device involved in this disclosure can be a base station, which may include multiple cells providing services to terminals. Depending on the specific application, the base station may also be called an access point, or a device in the access network that communicates with the wireless terminal device through one or more sectors on the air interface, or other names. The access network device can be used to exchange received air frames with Internet Protocol (IP) packets, acting as a router between the wireless terminal device and the rest of the access network, where the rest of the access network may include an Internet Protocol (IP) communication network. The access network device can also coordinate the attribute management of the air interface. For example, the access network equipment involved in this disclosure can be a Base Transceiver Station (BTS) in a Global System for Mobile communications (GSM) or Code Division Multiple Access (CDMA), or an Access Network Device (NodeB) in Wide-band Code Division Multiple Access (WCDMA). It can also be an Evolutionary Node B (eNB or e-NodeB) in a Long Term Evolution (LTE) system, a 5G Base Station (gNB) in a Next Generation System, or a Home Evolved Node B (HeNB), relay node, femto, pico, etc., and is not limited in this disclosure. In some network structures, the access network equipment may include centralized unit (CU) nodes and distributed unit (DU) nodes, which may be geographically separated.

[0337] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0338] This disclosure is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-executable instructions. These computer-executable instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more flowchart illustrations and / or one or more block diagrams.

[0339] These processor-executable instructions may also be stored in a processor-readable memory that can instruct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the processor-readable memory produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0340] These processor-executable instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational 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 one or more flowcharts and / or one or more block diagrams.

[0341] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A handover method applied to an access network device, comprising: determining that a terminal served by the access network device needs to reselect an access and mobility management function (AMF) 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); initiating NG handover 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 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: determining that the terminal served by the access network device needs to reselect the AMF in a 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, according to the configuration information of the OAM, that the current location of the access network device corresponds to the second AMF; the OAM configures to release or suspend an NG connection between the access network device and the first AMF; determining, according to the configuration information of the OAM, that the current location of the terminal corresponds to the second AMF; wherein the second AMF is different from the first AMF.

3. The handover method of claim 2, wherein, The method further comprises: sending, to the second AMF, an 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 sending, to the second AMF, a 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.

4. The handover method of claim 2, wherein, The NG handover 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 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.

6. The handover method of claim 5, wherein, The method further comprises: sending, to the first AMF, a 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.

7. The handover method of claim 4, 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 of the access network device served by the access network device corresponding to the current location of the access network device and configured by the OAM.

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

9. The handover method of claim 7 or 8, wherein, The method further includes: broadcasting the TA identity and the cell identity corresponding to the second cell.

10. The handover method of claim 1, wherein, The method further includes: releasing the NG connection between the first AMF and the access network device, or suspending the NG connection between the first AMF and the access network device.

11. An access network device comprising a memory, a transceiver, and a processor. The memory is configured to store a computer program. The transceiver is configured to transceive data under the control of the processor. The processor is configured to read the computer program in the memory and perform the following operations: determining, according to one or more of a current location of the 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 it is necessary to reselect an access and mobility management function (AMF) for the terminal served by the access network device; initiating an NG handover for the terminal to a first AMF; wherein the first AMF is an AMF serving the terminal.

12. The access network device of claim 11, wherein, The determining, according to one or more of a current location of the 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 it is necessary to reselect an access and mobility management function (AMF) for the terminal served by the access network device, comprises: determining, according to one or more of the following conditions, that it is necessary to reselect an AMF for the terminal served by 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, it is determined that the current location of the access network device corresponds to a 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 a second AMF; wherein the second AMF is different from the first AMF.

13. The access network device of claim 12, wherein, The operations further include: 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 sending a first radio access network configuration update message to the second AMF, the first radio access network configuration update message containing a 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 a base station identity corresponding to the current location of the access network device.

14. The access network device of claim 12, wherein, The NG handover for the terminal is used to change the AMF serving the terminal from the first AMF to the second AMF.

15. The access network device of claim 14, wherein, The NG handover for the terminal is also used to hand over the terminal in a first cell; wherein the first cell is a serving cell of the terminal.

16. The access network device of claim 15, wherein, The operations further include: sending a first NG handover request message to the first AMF, 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.

17. The access network device of claim 14, wherein, The NG handover for the terminal is further used to hand over 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 served by the access network device and corresponding to the current location of the access network device.

18. The access network device of claim 17, wherein, The operations further include: sending a second NG handover request message to the first AMF, the second NG handover request message containing a TA identifier corresponding to the current location of the access network device and served by the access network device, or an AMF identifier corresponding to the current location of the access network device.

19. The access network device of claim 17 or 18, wherein, The operations further include: broadcasting a TA identifier and a cell identifier corresponding to the second cell.

20. The access network device of claim 11, wherein, The operations further include: releasing an NG connection with the first AMF or suspending the NG connection with the first AMF.

21. A handover apparatus, 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 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 management and maintenance (OAM); a switching unit configured to initiate an NG handover for the terminal to a first AMF, wherein the first AMF is an AMF serving the terminal.

22. A processor-readable storage medium, the processor-readable storage medium storing a program for causing a processor to perform the method of any one of claims 1 to 10.

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