WO2021051313A1

WO2021051313A1 - Switching method and device

Info

Publication number: WO2021051313A1
Application number: PCT/CN2019/106474
Authority: WO
Inventors: 刘菁; 史玉龙; 戴明增; 曹振臻; 朱元萍; 卓义斌
Original assignee: 华为技术有限公司
Priority date: 2019-09-18
Filing date: 2019-09-18
Publication date: 2021-03-25
Also published as: CN114402661B; CN114402661A

Abstract

The present invention relates to the field of communications. Provided in embodiments of the present invention are a switching method and device. The method comprises: receiving a measurement result reported by an IAB node, the measurement result comprising at least one of a signal measurement result of a source cell and a signal measurement result of a target cell, wherein the source cell belongs to a source IAB donor, and the target cell belongs to a target IAB donor; and if it is determined, on the basis of the measurement result, that the IAB node is to be switched to the target IAB donor, sending, to the target IAB donor, context of the IAB node and context of one or more subnodes of the IAB node, wherein the one or more subnodes of the IAB node include a user equipment unit (UE) and/or other IAB nodes. The invention provides a switching solution applicable to a scenario of a mobile IAB node.

Description

Switching method and device

Technical field

The embodiments of the present application relate to the field of communications, and in particular, to a handover method and device.

Background technique

In the prior art, user equipment (User Equipment, UE) can be attached to an Integrated Access and Backhaul (IAB) node (node) to access an IAB donor (donor). Generally, since the IAB node is a fixed node (not movable), the handover in the prior art only needs to consider the handover of the UE between the source IAB donor and the target IAB donor.

However, with the development of mobile technology, IAB node can be set in mobile application scenarios such as trains, cars, drones, etc. For this scenario, IAB node and its child nodes (such as UE or other IAB nodes) can be used as one The whole (for example: group) moves together, but a perfect handover scheme has not yet been proposed.

Summary of the invention

The present application provides a switching method and device, so as to provide a complete switching solution and improve the diversity of application scenarios.

In order to achieve the above objectives, this application adopts the following technical solutions:

In the first aspect, the embodiments of this application provide a handover method, which can be applied to a source IAB donor. The method may include: the source IAB donor receives the measurement result reported by the IAB node, and the measurement result includes the signal measurement result of the source cell and the target At least one of the signal measurement results of the cell, where the source cell belongs to the source IAB donor, and the target cell belongs to the target IAB donor. Then, the source IAB donor determines to switch the IAB node to the target IAB donor based on the measurement result reported by the IAB node, and can send the context information of the IAB node and the context information of at least one child node of the IAB node to the target IAB donor. Wherein, at least one child node of the IAB node includes user equipment UE and/or other IAB nodes.

Based on the above method, the source IAB donor can obtain the signal status between the IAB node and the source IAB donor and/or between the IAB node and the target IAB donor node based on the measurement results reported by the IAB node, so as to determine whether the IAB node needs to be And at least one child node of the IAB attached to it switches to the target IAB donor. Moreover, after the source IAB donor determines to switch the IAB node and its at least one child node to the target IAB donor, it can send the context information of the locally cached IAB node and the context information of at least one child node to the target IAB donor, so that The target IAB donor prepares for the handover of the IAB node and at least one child node, so as to realize the handover of the IAB node and at least one child node attached to it from the source IAB donor to the target IAB donor. In addition, the present application can be applied to the scenario of moving the IAB node, that is, in the scenario where the IAB node is moving and the IAB donor needs to be switched, the group switching of the IAB node and at least one child node attached to it can be realized. Optionally, this application can also be applied to the handover scenarios of fixed IAB nodes. For example, the IAB node is deployed in the overlapping area covered by the source IAB donor and the target IAB donor. This can also be achieved when the IAB node needs to switch the IAB donor. Group switching of the IAB node and at least one child node attached to it. That is to say, as long as the IAB node and at least one child node attached to it perform group switching, it is applicable to the solution of this application, and this application is not limited.

In a possible implementation manner, the method may further include: the source IAB donor receives the first configuration information sent by the target IAB donor that the IAB node needs to switch to the target IAB donor, and at least one child node of the IAB node switches to the target IAB The second configuration information required by the donor; and, the source IAB donor sends the second configuration information to at least one child node of the IAB node, and sends the first configuration information to the IAB node.

Based on the above method, the target IAB donor can prepare the switch between the IAB node and the at least one child node of the IAB node based on the context information of the IAB node and the context information of at least one child node of the IAB node received from the source IAB donor. For example, sending the first configuration information required for switching to the target IABdonor to the IAB node, and sending the second configuration information required for switching to the target IABdonor to at least one child node of the IAB node, so as to transfer the second configuration information to the source IAB donor. The configuration information and the first configuration information are respectively sent to at least one child node of the IAB node and the IAB node.

In a possible implementation manner, if at least one child node of the IAB node includes a UE, the second configuration information includes at least one of the following: configuration information of the PDCP layer of the UE peering with the target IAB donor, the UE and the target IAB donor The security algorithm used between the UE and the target IAB donor and the NCC value corresponding to the security key used between the UE and the target IAB donor.

Based on the above method, the UE, which is a child node of the IAB node, can communicate with the target IAB donor based on the second configuration information after switching to the target IAB donor.

In a possible implementation manner, the context information of the IAB node and the context information of at least one child node of the IAB node are carried in the first message; or the context information of the IAB node is carried in the first message, and the IAB node The context information of at least one child node of is carried in n second messages, the n second messages correspond to at least one child node one-to-one, and n is equal to the number of at least one child node.

Based on the above method, the source IAB donor can send the context information of the IAB node and the context information of at least one child node to the target IAB donor in two ways. One is the context information of the IAB node and the context information of at least one child node. Carried in the first message. Optionally, the first message may be a handover request message in 3GPP, or a newly defined XnAP message. The other is that the context information of the IAB node and the context information of at least one child node are carried in different messages.

In a possible implementation manner, if at least one child node of the IAB node includes a UE, sending context information of the IAB node and context information of at least one child node of the IAB node to the target IAB donor also includes: sending to the target IAB donor The identification information of the UE; the identification information includes the cell global identification CGI used by the UE to access the cell of the IAB node, and the cell radio network temporary identification C-RNTI of the UE in the cell of the IAB node.

Based on the above method, if at least one child node of the IAB node includes the UE, for the UE handover, the source IAB donor sends the context information of the UE to the target IAB donor, and also needs to send the UE identification information to the target IAB donor, so that the target The IAB donor matches or associates the context information of the UE with the identification information of the UE.

In a possible implementation, if at least one child node of the IAB node includes other IAB nodes, the context information of the other IAB nodes includes the context information of the distributed unit DU of the other IAB nodes; the context information of the DU includes at least one of the following : DU identification information, identification CGI of at least one cell served by DU, physical cell identification PCI of at least one cell served by DU, RRC version supported by DU, and indication information of whether at least one cell served by DU is activated.

Based on the above method, if at least one child node of the IAB node includes other IAB nodes, for the handover of other IAB nodes, the source IAB donor can send to the target IAB donor the identification information of the DU of the other IAB node and the status of at least one cell served by the DU. Instruction information to be activated, etc. In other words, there may be inactive cells in at least one cell served by the DU, and the target IAB donor may determine which of the at least one cell served by the DU is an activated cell based on the indication information.

In a possible implementation manner, sending the context information of the IAB node and the context information of at least one child node of the IAB node to the target IAB donor also includes: sending the topology information to the target IAB donor, and the topology information is used to indicate that the IAB node and the The topological relationship between at least one child node of the IAB node and/or between multiple child nodes of the IAB node.

Based on the above method, the present application can realize the handover between the IAB node and at least one child node of the IAB node in a multi-hop scenario.

In a possible implementation, the method may further include: the source IAB donor receives the new cell global identity and the old cell global identity of at least one cell served by the DU of the IAB node sent by the target IAB donor; and sends the IAB node’s global identity to the IAB node The global identity of the new cell and the global identity of the old cell of at least one cell served by the DU; or, the source IAB donor receives the global identity of the new cell of at least one cell served by the DU of the IAB node sent by the target IAB donor; and sends the IAB node’s global identity to the IAB node The global identity of the new cell of at least one cell served by the DU. Among them, the new cell global identifier is the cell global identifier used by the IAB node to switch to the target IAB donor; the old cell global identifier is the IAB node access source IAB donor using the cell global identifier.

Based on the above method, the IAB node can obtain the global identity of the new cell allocated by the target IAB donor for at least one cell served by the DU of the IAB node, so that the IAB node can update the local global identity of the old cell.

In the second aspect, the embodiment of the present application provides a handover method, which is applied to access a turn-integrated IAB node. The method includes: the IAB node sends a measurement result to the source IAB donor; and the IAB node can receive the source IAB donor. The first configuration information required for the IAB node to switch to the target IAB donor and the second configuration information required for at least one child node of the IAB node to switch to the target IAB donor; at least one child node of the IAB node includes user equipment UE and/or Other IAB nodes; then, the IAB node sends second configuration information to at least one child node.

In a possible implementation manner, the method further includes: obtaining the new cell global identity CGI of at least one cell served by the DU of the IAB node; where the new cell global identity is the cell global identity used by the IAB node to switch to the target IAB donor; The IAB node access source IAB donor uses the global identity of the old cell.

Based on the above method, the old identification information of at least one cell served by the DU of the IAB node, that is, the update of the global identification CGI of the old cell, is implemented, so that the IAB node can update the identification information of at least one child node based on the new CGI.

In a possible implementation manner, the method further includes: sending an indication message to the target IAB donor, where the indication message includes the old cell global identity and the new cell global identity of at least one cell served by the DU.

Based on the above method, when the IAB node switches to the target IAB donor, it can indicate the old cell global identity and the new cell global identity to the target IAB donor, so that the target IAB donor can learn the global identity of the new cell of the IAB node and update the locally cached UE’s The identifier, that is, the old CGI and C-RNTI of the IAB node accessed by the UE are updated to the new CGI and C-RNTI.

In a possible implementation manner, the indication message also includes indication information of whether at least one cell served by the DU is activated.

In a possible implementation, if at least one child node includes a UE, the method further includes: the IAB node switches to the target IAB donor, and receives the identification information of the UE sent by the target IAB donor; wherein the identification information of the UE includes the UE access The old cell global identity of the cell served by the DU of the IAB node and the cell radio network temporary identity C-RNTI of the UE in the cell served by the DU; or, the identification information of the UE includes the new cell of the cell served by the DU of the IAB node. The global identity of the cell and the C-RNTI of the UE in the cell served by the DU.

Based on the above method, the IAB node and the target IAB donor can unify the UE’s identification information, that is, both update the UE’s identification information to new identification information. The new identification information includes the new CGI and C-RNTI, so that the IAB node and the target IAB donor can be Based on the new identification information of the UE, the corresponding UE is identified and a bearer is established for the UE.

In a possible implementation, if at least one child node includes the UE, before the IAB node switches to the target IAB donor, the method further includes: receiving the F1 interface identifier of the target IAB donor assigned to the UE by the source IAB donor, and the F1 interface It is the interface between the IAB node and the target IAB donor.

Based on the above method, the IAB node and the target IAB donor can also identify the corresponding UE through the identifier of the F1 interface, so as to establish a corresponding bearer for the UE.

In the third aspect, the embodiments of the present application provide a switching device, which can be applied to a source IAB donor. The device includes: a memory and a processor, the memory and the processor are coupled, the memory stores program instructions, and the program instructions are executed by the processor At this time, the handover device is caused to perform the following steps: receive the measurement result reported by the IAB node, the measurement result includes at least one of the signal measurement result of the source cell and the signal measurement result of the target cell, where the source cell belongs to the source IAB donor, and the target cell Belongs to the target IAB donor; based on the measurement result, it is determined to switch the IAB node to the target IAB donor, then the context information of the IAB node and the context information of at least one child node of the IAB node are sent to the target IAB donor; among them, at least one child of the IAB node The nodes include user equipment UE and/or other IAB nodes.

In a possible implementation manner, when the program instructions are executed by the processor, the switching device executes the following steps: receiving the first configuration information required by the IAB node from the target IAB donor to switch to the target IAB donor, and at least the IAB node The second configuration information required for a child node to switch to the target IAB donor; sending the second configuration information to at least one child node of the IAB node, and sending the first configuration information to the IAB node.

In a possible implementation manner, the context information of the IAB node and the context information of at least one child node of the IAB node are carried in the first message; or, the context information of the IAB node is carried in the first message, and at least the context information of the IAB node The context information of a child node is carried in n second messages, the n second messages correspond to at least one child node one-to-one, and n is equal to the number of at least one child node.

In a possible implementation, if at least one child node of the IAB node includes a UE, the context information of the IAB node and the context information of at least one child node of the IAB node are sent to the target IAB donor. When the program instructions are executed by the processor, Make the handover device perform the following steps: send the identification information of the UE to the target IAB donor; the identification information includes the cell global identification CGI used by the UE to access the cell of the IAB node, and the cell radio network temporary identification of the UE in the cell of the IAB node C-RNTI.

In a possible implementation manner, the context information of the IAB node and the context information of at least one child node of the IAB node are sent to the target IAB donor. When the program instructions are executed by the processor, the switching device executes the following steps: Send topology information, where the topology information is used to indicate the topological relationship between the IAB node and at least one child node of the IAB node and/or between multiple child nodes of the IAB node.

In a possible implementation manner, when the program instructions are executed by the processor, the handover device executes the following steps: the source IAB donor receives the new cell global identity and the old cell of at least one cell served by the DU of the IAB node sent by the target IAB donor Global ID; send to the IAB node the global ID of the new cell and the global ID of the old cell of at least one cell served by the DU of the IAB node; or, the source IAB donor receives the new cell of at least one cell served by the DU of the IAB node sent by the target IAB donor Global identity: Send the global identity of the new cell of at least one cell served by the DU of the IAB node to the IAB node. Among them, the new cell global identifier is the cell global identifier used by the IAB node to switch to the target IAB donor; the old cell global identifier is the IAB node access source IAB donor using the cell global identifier.

In a fourth aspect, an embodiment of the present application provides a switching device, which can be applied to an IAB node. The device includes: a memory and a processor, the memory and the processor are coupled, the memory stores program instructions, and the program instructions are executed by the processor. , The switching device performs the following steps: sending the measurement result to the source IAB donor; receiving the first configuration information required for the IAB node to switch to the target IAB donor from the source IAB donor and at least one child node of the IAB node to switch to the target IAB donor. Required second configuration information; at least one child node of the IAB node includes user equipment UE and/or other IAB nodes; and sends the second configuration information to at least one child node.

In a possible implementation manner, when the program instructions are executed by the processor, the handover device executes the following steps: Obtain the new cell global identity CGI of at least one cell served by the DU of the IAB node; where the new cell global identity is the IAB node Switch to the global identity of the cell used by the target IAB donor; the global identity of the old cell used by the IAB node to access the source IAB donor.

In a possible implementation manner, when the program instructions are executed by the processor, the switching device executes the following steps after acquiring the new cell global identity of at least one cell served by the DU of the IAB node: Send an instruction message to the target IAB donor, The indication message includes the old cell global identity and the new cell global identity of at least one cell served by the DU.

In a possible implementation, if at least one child node includes a UE, when the program instructions are executed by the processor, the switching device executes the following steps: the IAB node switches to the target IAB donor, and receives the UE identifier sent by the target IAB donor Information; wherein, the UE’s identification information includes the old cell global identity of the cell served by the DU of the IAB node and the UE’s cell radio network temporary identity C-RNTI in the cell served by the DU; or, the UE’s identity information includes the UE The global identity of the new cell of the cell served by the DU accessing the IAB node and the C-RNTI of the UE in the cell served by the DU.

In a possible implementation, if at least one child node includes a UE, before the IAB node switches to the target IAB donor, when the program instructions are executed by the processor, the switching device executes the following steps: Receive the target IAB donor sent by the source IAB donor The identifier of the F1 interface assigned to the UE. The F1 interface is the interface between the IAB node and the target IAB donor.

In a fifth aspect, an embodiment of the present application also provides a handover system. The system may include a source IAB donor, a target IAB donor, an IAB node, and at least one child node of the IAB node, where at least one child node of the IAB node includes UE and / Or other IAB nodes; among them, the IAB node is used to send the measurement result to the source IAB donor, the measurement result includes at least one of the signal measurement result of the source cell and the signal measurement result of the target cell, where the source cell belongs to the source IAB Donor, the target cell belongs to the target IAB donor; the source IAB donor is used to determine to switch the IAB node to the target IAB donor based on the measurement result, and then send the context information of the IAB node and the context of at least one child node of the IAB node to the target IAB donor Information; the target IAB donor is used to send to the source IAB the first configuration information required by the IAB node to switch to the target IAB donor and at least the IAB node’s first configuration information based on the context information of the IAB node and the context information of at least one child node of the IAB node The second configuration information required by a child node to switch to the target IAB donor; the source IAB donor is also used to send the first configuration information and the second configuration information to the IAB node; the IAB node is also used to receive the first configuration information and the first configuration information 2. Configuration information, and sending the second configuration information to at least one child node.

In a sixth aspect, an embodiment of the present application provides a computer-readable medium for storing a computer program, and the computer program includes instructions for executing the first aspect or any possible implementation of the first aspect.

In a seventh aspect, an embodiment of the present application provides a computer-readable medium for storing a computer program, and the computer program includes instructions for executing the second aspect or any possible implementation of the second aspect.

In an eighth aspect, an embodiment of the present application provides a computer program, the computer program including instructions for executing the first aspect or any possible implementation of the first aspect.

In a ninth aspect, an embodiment of the present application provides a computer program, and the computer program includes instructions for executing the second aspect or any possible implementation of the second aspect.

In a tenth aspect, an embodiment of the present application provides a chip, which includes a processing circuit and transceiver pins. Wherein, the transceiver pin and the processing circuit communicate with each other through an internal connection path, and the processing circuit executes the method in the first aspect or any one of the possible implementations of the first aspect to control the receiving pin to receive the signal, and Control the sending pin to send signals.

In an eleventh aspect, an embodiment of the present application provides a chip, which includes a processing circuit and transceiver pins. Wherein, the transceiver pin and the processing circuit communicate with each other through an internal connection path, and the processing circuit executes the method in the second aspect or any one of the possible implementations of the second aspect to control the receiving pin to receive the signal, and Control the sending pin to send signals.

Description of the drawings

FIG. 1 is one of the schematic diagrams of a scenario provided by an embodiment of the application;

FIG. 2 is one of schematic diagrams of a scenario provided by an embodiment of the application;

FIG. 3 is one of schematic diagrams of a scenario provided by an embodiment of the application;

FIG. 4 is one of schematic diagrams of a scenario provided by an embodiment of the application;

FIG. 5 is one of schematic diagrams of a scenario provided by an embodiment of the application;

FIG. 6 is one of the schematic diagrams of the handover preparation process provided by the embodiment of the application;

FIG. 7 is one of the schematic diagrams of the handover preparation process provided by the embodiment of the application;

FIG. 8 is one of the schematic flow diagrams of the handover process provided by the embodiment of the application;

FIG. 9 is one of the schematic diagrams of a protocol stack provided by an embodiment of this application;

FIG. 10 is one of the schematic diagrams of a protocol stack provided by an embodiment of this application;

FIG. 11 is one of the schematic flowcharts of the handover method provided by the embodiment of this application;

FIG. 12 is one of the schematic flowcharts of the handover method provided by the embodiment of the application;

FIG. 13 is a schematic structural diagram of an IAB donor provided by an embodiment of this application;

FIG. 14 is a schematic structural diagram of an IAB node provided by an embodiment of this application;

FIG. 15 is a schematic structural diagram of a device provided by an embodiment of this application.

detailed description

The technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of them. Based on the embodiments in this application, all other embodiments obtained by a person of ordinary skill in the art without creative work shall fall within the protection scope of this application.

The term "and/or" in this article is only an association relationship describing the associated objects, which means that there can be three relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, exist alone B these three situations.

The terms "first" and "second" in the description and claims of the embodiments of the present application are used to distinguish different objects, rather than to describe a specific order of objects. For example, the first target object and the second target object are used to distinguish different target objects, rather than to describe the specific order of the target objects.

In the embodiments of the present application, words such as "exemplary" or "for example" are used as examples, illustrations, or illustrations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferable or advantageous than other embodiments or design solutions. To be precise, words such as "exemplary" or "for example" are used to present related concepts in a specific manner.

In the description of the embodiments of the present application, unless otherwise specified, the meaning of "plurality" means two or more. For example, multiple processing units refer to two or more processing units; multiple systems refer to two or more systems.

In this application, in order to distinguish, the IAB node that triggers the handover (or triggers the group handover) is called the handover IAB node, and the handover IAB node includes the following four scenarios before the handover is performed:

Scenario 1: The source IAB donor is the parent node of the handover IAB node (the handover IAB node is the child node of the source IAB donor), and the handover IAB node is the parent node of the UE (the UE is the child node of the handover IAB node). As shown in Figure 1.

Scenario 2: The source IAB donor is the parent node of the switching IAB node, the switching IAB node is the parent node of the other IAB node (the other IAB node is the child node of the switching IAB node), and the other IAB node is the parent node of the UE (the UE is another IAB child node of node). That is: switching between IAB node and UE has one or more other IAB nodes, for example: switching IAB node is the parent node of IAB node A, IAB node A is the parent node of UE, or IAB node A is IAB node B Parent node, IAB node B is the parent node of the UE. as shown in picture 2.

Scenario 3: The source IAB donor is the parent node of other IAB nodes (other IAB nodes are the child nodes of the source IAB donor), and other IAB nodes are the parent nodes of the switch IAB node (the switch IAB node is the child node of other IAB nodes), switch The IAB node is the parent node of the UE. That is: there are one or more other IAB nodes between the source IAB donor and the switching IAB node, for example: the source IAB donor is the parent node of IAB node C, IAB node C is the parent node of switching IAB node, or IAB node C is The parent node of IAB node D, and IAB node D is the parent node of switching IAB node. As shown in Figure 3.

Scenario 4: The source IAB donor is the parent node of another IAB node, the other IAB node is the parent node of the switch IAB node, and the switch IAB node is the parent node of other IAB nodes except other IAB nodes, except for other IAB nodes The other IAB nodes are the parent nodes of the UE. That is, there are one or more other IAB nodes between the source IAB donor and the handover IAB node, and there are one or more other IAB nodes between the handover IAB node and the UE. For example, the source IAB donor is the parent node of IAB node C, IAB node C is the parent node of switching IAB node, or IAB node C is the parent node of IAB node D, and IAB node D is the parent node of switching IAB node. Handover IAB node is the parent node of IAB node A, IAB node A is the parent node of UE, or IAB node A is the parent node of IAB node B, and IAB node B is the parent node of UE. As shown in Figure 4.

After switching the IAB node, the following two scenarios also exist, namely: the target IAB donor is the parent node of the switching IAB node (the switching IAB node is the child node of the target IAB donor), or the target IAB donor and the switching IAB node There are one or more other IAB nodes.

Handover IAB node During the handover process, all or part of the sub-nodes of the IAB node (for example: UE or other IAB nodes) are handed over along with the IAB node.

For simplicity of description, this patent mainly uses scenarios 1 and 2 as examples, that is, before switching the IAB node, the source IAB donor is the parent node of the switching IAB node (the switching IAB node is the child node of the source IAB donor). The switching IAB node is the parent node of the UE (the UE is the child node of the switching IAB node), or the switching IAB node is the parent node of other IAB nodes (the other IAB node is the child node of the switching IAB node), and the other IAB nodes are the UE’s Parent node (UE is a child node of other IAB node). After switching the IAB node, the target IAB donor is the parent node of the switching IAB node.

This application is also applicable to other scenarios and will not be repeated here.

The foregoing application scenarios or communication systems can be used to support fourth-generation (4G) access technologies, such as long-term evolution (LTE) access technologies; or, the communication system can also support fifth-generation (fifth generation) access technologies. generation, 5G) access technology, such as new radio (NR) access technology.

It should be noted that under the CU-DU separation architecture of the fifth-generation mobile communication technology (5th-Generation, 5G), the IAB node consists of the IAB node mobile terminal (Mobile Termination, MT) and the IAB node distributed unit (Distributed Unit, DU) consists of two parts. IAB donor consists of IAB donor Central Unit (CU) and IAB donor DU. The interface between IAB donor CU and IAB donor DU is the F1 interface, IAB donor CU and IAB node DU The interface between is an F1 interface (or F1* interface), which is not limited in this application. Among them, for IAB node, IAB node DU has some of the functions of the base station, such as the physical layer (PHY) of the base station, the media access control (MAC) layer, and the radio link control (Radio Link Control). , The function of the RLC) layer is used to provide access services to the child nodes attached to it. The IAB node MT is connected to the parent node of the IAB node according to the function similar to the UE in the air interface. For IAB donor, IAB donor DU has similar functions to IAB node DU. The IAB donor CU is used to control and manage all IAB nodes and UEs under it. Among them, IAB donor CU can further adopt the architecture of separating the user plane and the control plane, that is, including the IAB donor CU-UP (user plane) entity and the IAB donor CU-CP (control plane) entity, IAB donor CU-UP and IAB The interface between the donor CU-CP is an E1 interface.

In conjunction with Figure 1, Figure 5 shows an exemplary application scenario diagram. In Figure 5, the application scenario includes: Access and Mobility Management Function (AMF)/User Plane Function (User Plane Function, UPF), source IAB donor, target IAB donor, handover IAB node and UE.

In combination with the above-mentioned schematic diagram of the application scenario shown in Figure 5, the following describes the specific implementation scheme of the present application:

Option One

Specifically, in this application, the process of switching the IAB node and its child nodes to the target IAB donor can be divided into two parts. The first part is the handover preparation process. The source IAB donor migrates the context information of the IAB node and its child nodes to the target IAB donor, and notifies the target IAB donor to prepare corresponding resources for the IAB node and its child nodes. The specific steps can be shown in Figure 6 or Figure 7. The second part is the handover process. After the target IAB donor is ready, the handover process between the UE and the IAB node can be executed. The specific steps are shown in Figure 8.

In conjunction with FIG. 5, FIG. 6 is a schematic diagram of a handover preparation process provided in an embodiment of this application. In FIG. 6:

Step 101: The source IAB donor CU-CP sends a handover request message (Handover Request) to the target IAB donor CU-CP.

Specifically, the source IAB donor CU-CP determines that it is necessary to switch the IAB node and its child nodes to the target IAB donor. There are several possibilities:

As a possibility, based on the measurement results reported by the handover IAB node MT, the measurement results include the signal quality measurement results of the handover IAB node MT on the serving cell and the neighbor cell, where the neighbor cell includes the cell of the target IAB donor. For example, when the measurement result of the cell of the target IAB donor is greater than the measurement result of the serving cell, the source IAB donor CU-CP decides that it needs to switch the IAB node MT to the target IAB donor. In addition, the source IAB donor CU-CP can obtain the instruction information for instructing the switch IAB node to be a mobile IAB node during the initial access process of the IAB node MT. The source IAB donor CU-CP can determine the need to change the Switch the child node of the IAB node and switch the IAB node to the target IAB donor together.

Specifically, when the IAB node MT initially accesses the source IAB donor, it will send a mobile IAB node indication message to the source IAB donor CU-CP to indicate that the mobile IAB node is currently accessing the network. The indication information may be carried in the RRC connection establishment request message (RRCSetupRequest), or may be carried in the RRC connection establishment complete message (RRCSetupComplete).

As another possibility, based on the measurement results reported by the handover IAB node MT, the source IAB donor CU-CP decides that the handover IAB node MT needs to be switched to the target IAB donor. In addition, based on an indication information carried during the initial access process of the handover IAB node MT or the measurement report process, the source IAB donor CU-CP decides that the child node of the handover IAB node and the handover IAB node need to be switched to the target IAB donor together. The indication information is used to instruct the source IAB donor CU-CP to regard the switching IAB node and the child nodes of the IAB node as a group, or to instruct the switching IAB node child nodes and the switching IAB node to switch together. Exemplarily, the indication information may be indication information of group movement, or indication information of group switching, or group identification.

Still referring to FIG. 6, the handover request message includes at least one of the following information: UE context information, UE identification information, context information for handover IAB node MT, handover IAB node MT identification information, and handover IAB node DU Contextual information.

Wherein, the context information of the UE includes at least one of the following information: QoS information of the UE service, configuration information carried by the UE air interface (for example: PDCP/RLC/MAC/PHY layer configuration, and/or Logical Channel (LCH) Configuration, etc.), the security algorithms supported by the UE, etc.

Similar to the context information of the UE, the context information for switching IAB node MT includes at least one of the following information: switching IAB node MT QoS information, switching IAB node MT air interface bearer configuration information, switching IAB node MT supporting security algorithms, and so on.

The context information of the handover IAB node DU includes at least one of the following information: the identity of the DU, the identity CGI of at least one cell served by the DU, the physical cell identity PCI of at least one cell served by the DU, the RRC version supported by the DU, and at least the Information indicating whether a cell is activated. Among them, the identifier of the DU may be the DU ID, or may also be the name of the DU (DU name). The indication information of whether at least one cell served by the DU is activated may be a displayed indication or an implicit indication. If it is an implicit indication, as another example, the context information of the handover IAB node DU includes at least one of the following information: the identity of the DU, the identity of at least one activated cell served by the DU, the CGI, and the identity of at least one activated cell served by the DU. The physical cell identifier PCI, the identifier CGI of at least one inactive cell served by the DU, the physical cell identifier PCI of at least one inactive cell served by the DU, and the RRC version supported by the DU.

The identification information of the UE includes but is not limited to: Cell Global Identifier (CGI) and Cell Radio Network Temporary Identifier (C-RNTI). Among them, CGI is the cell global identity of the cell where the UE is attached, and C-RNTI is the identity allocated to the UE by the cell where the UE is attached. It should be noted that, in this application, if the UE is a child node of the handover IAB node, before and after the handover of the IAB node, the UE is always attached to the same cell where the IAB node is handed over, but because the handover IAB node is from the source IAB donor Switching to the target IAB donor causes the cell identification CGI of the cell to change, from the old CGI (old CGI) to the new CGI (new CGI). The old CGI belongs to the source IAB donor, that is, the old CGI contains the base station identifier of the source IAB donor. The new CGI belongs to the target IAB donor, that is, the new CGI contains the base station identifier of the target IAB donor. Similarly, if there are other IAB nodes between the UE and the handover IAB node (that is, the other IAB node is the child node of the handover IAB node, and the UE is the child node of the other IAB node), before and after the handover IAB node, The UE is always attached to the same cell of other IAB nodes, and other IAB nodes are always attached to the same cell where the IAB node is handed over. However, because the host node changes from the source IAB donor to the target IAB donor, other IAB nodes and other IAB nodes are always attached to the same cell. The F1 interface between the host nodes changes. Therefore, the cell identification CGI of the cell where the UE is attached to another IAB node changes, from the old CGI to the new CGI.

In order to distinguish the identification information of the UE in the following embodiments, before the handover of the IAB node, the identification information of the UE is composed of the old CGI and C-RNTI. After switching the IAB node, the identification information of the UE is composed of the new CGI and C-RNTI.

Optionally, after the target IAB donor CU-CP receives the context information of the UE and the identification information of the UE, it can associate (or match) the context information of the UE with the identification information of the UE. That is, the target IAB donor CU-CP can Through the identification information of the UE, the context corresponding to the UE is found.

Optionally, the handover request message may be an Xn interface application protocol (Application Protocol, XnAP) message. In an example, the handover request message may be a Handover Request message defined in the 3GPP standard. In another example, the handover request message may also be a newly defined XnAP message. That is to say, in this application, when the handover IAB node prepares for handover, the Handover Request message defined in the 3GPP standard can be used to carry the context information of the UE and/or the identification information of the UE. An XnAP message can also be redefined. The structure of the message can be set based on the information it carries to reduce signaling overhead.

Step 102: The target IAB donor CU-CP sends a Bearer Context Setup Request (Bearer Context Setup Request) message to the target IAB donor CU-UP.

Optionally, the message includes at least one of the following information: NG interface tunnel identification information allocated by the UPF for different bearers of the UE and NG interface tunnel identification information allocated by the UPF for switching different bearers of the IAB node MT. Optionally, the NG interface tunnel identification information allocated by the UPF for the UE may be a GPRS Tunneling Protocol (GPRS Tunneling Protocol, GTP) tunnel endpoint identifier (Tunnel Endpoint Identifier, TEID) and an IP address of the UPF. It should be noted that the NG interface tunnel identification information allocated by the UPF for different bearers of the UE is used to establish an uplink GTP tunnel from the target IAB donor CP-UP to the UPF for different bearers of the UE. It should be noted that the tunnels between each network element, such as IAB donor CP-UP and UPF, or the tunnel between IAB node DU and IAB donor CU-UP, are bidirectional, for example: the target IAB described in this article The uplink GTP tunnel from the donor CP-UP to the UPF refers to the tunnel required by the target IAB donor CP-UP to send uplink data (uplink data refers to data from the UE) to the UPF. Conversely, the downlink GTP tunnel from the UPF to the target IAB donor CP-UP refers to the tunnel required by the UPF to send downlink data (downlink data refers to data sent to the UE) to the target IAB donor CP-UP.

Step 103: The target IAB donor CU-UP sends a bearer context setup response (Bearer Context Setup Response) message to the target IAB donor CU-CP.

Optionally, the message includes at least one of the following information: the target IAB donor CU-UP is the tunnel identification information allocated on the NG interface for the different bearers of the UE, and the target IAB donor CU-UP is the tunnel identification information allocated on the F1 interface for the different bearers of the UE. The tunnel identification information, the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface for the different bearers of the UE, and the target IAB donor CU-UP is the switch IAB node MT tunnel identification information allocated on the NG interface for the different bearers, and the target IAB donor CU-UP is the tunnel identification information allocated on the F1 interface for switching different bearers of the IAB node MT, and the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface for switching different bearers of the IAB node MT.

Optionally, the target IAB donor CU-UP is the tunnel identification information allocated on the NG interface for different bearers of the UE, which is used to establish a downlink GTP tunnel from the UPF to the target IAB donor CP-UP for the different bearers of the UE.

Optionally, the target IAB donor CU-UP is the tunnel identification information allocated on the F1 interface for different bearers of the UE, which is used to establish an uplink GTP tunnel from the handover IAB node DU to the target IAB donor CU-UP for the different bearers of the UE.

Optionally, the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface for different bearers of the UE, which is used to establish a forwarding tunnel from the source IAB donor CU-UP to the target IAB donor CU-UP for the different bearers of the UE. .

Optionally, the target IAB donor CU-UP is the tunnel identification information allocated on the NG interface for switching the different bearers of the IAB node MT, which is used to establish the downlink GTP from the UPF to the target IAB donor CP-UP for switching the different bearers of the IAB node MT tunnel.

Optionally, the target IAB donor CU-UP is the tunnel identification information allocated on the F1 interface to switch the different bearers of the IAB node MT, and is used to establish the different bearers of the switch IAB node MT from the target IAB donor DU to the target IAB donor CU-UP The uplink GTP tunnel.

Optionally, the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface to switch the different bearers of the IAB node MT, and is used to establish the transfer from the source IAB donor CU-UP to the target IAB donor for the different bearers of the switch IAB node MT. CU-UP forwarding tunnel.

Step 104: The target IAB donor CU-CP sends a UE Context Setup Request (UE Context Setup Request) message to the target IAB donor DU.

Optionally, this message can be used to instruct the target IAB donor DU to establish a context for switching the IAB node MT. Optionally, the message includes but is not limited to: the target IAB donor CU-UP is the tunnel identification information allocated on the F1 interface for switching different bearers of the IAB node MT. In other words, the target IAB donor CU-CP can use the UE Context Setup Request message to forward the tunnel identification information allocated on the F1 interface from the target IAB donor CU-UP to switch the IAB node MT to the target IAB donor DU for Instruct the target IAB donor DU to establish an uplink GTP tunnel from the target IAB donor DU to the target IAB donor CU-UP to switch different bearers of the IAB node MT.

It should be noted that in this step, the UE Context Setup Request message carries information related to switching IAB node MT. For switching IAB node, switching IAB node MT is equivalent to UE. Therefore, as another possibility, UE The Context Setup Request message may also be called MT Context Setup Request, and its structure can refer to the UE Context Setup Request message in the prior art, which will not be repeated here.

Step 105: The target IAB donor DU sends a UE Context Setup Response (UE Context Setup Response) message to the target IAB donor CU-CP.

Optionally, the message can be used to indicate that the target IAB donor DU has successfully established a context for switching the IAB node MT.

In conjunction with FIG. 5, FIG. 7 is a schematic diagram of the flow of handover preparation provided in an embodiment of this application. In FIG. 7:

Step 201: The source IAB donor CU-CP sends a Handover Request message to the target IAB donor CU-CP.

Optionally, the message includes at least one of the following information: context information of handover IAB node MT, identification information of handover IAB node MT, and context information of handover IAB node DU. Among them, the context information of switching IAB node MT, the identification information of switching IAB node MT, and the context information of switching IAB node DU can be found in step 101, which will not be repeated here.

Optionally, the Handover Request message may be a Handover Request message defined in the existing 3GPP standard, or may be a newly defined XnAP message, which is not limited in this application.

Step 202: The source IAB donor CU-CP sends an XnAP message to the target IAB donor CU-CP.

Optionally, the message includes at least one of the following information: context information of the UE and identification information of the UE. Among them, the context information of the UE and the identification information of the UE can be described in step 101, which will not be repeated here.

Optionally, the XnAP message may be a Handover Request message defined in the existing 3GPP standard, or may be a newly defined XnAP message, which is not limited in this application.

It should be noted that the order of step 201 and step 202 is not limited.

Step 203: The target IAB donor CU-CP executes the Bearer Context Setup process corresponding to the UE.

The specific ones include:

1. The target IAB donor CU-CP sends a Bearer Context Setup Request message to the target IAB donor CU-UP. Optionally, the message includes but is not limited to NG interface tunnel identification information allocated by the UPF for different bearers of the UE.

2. The target IAB donor CU-UP sends a Bearer Context Setup Response message to the target IAB donor CU-CP. Optionally, the message includes at least one of the following information: the target IAB donor CU-UP is the tunnel identification information allocated on the NG interface for the different bearers of the UE, and the target IAB donor CU-UP is the tunnel identification information allocated on the F1 interface for the different bearers of the UE. The tunnel identification information and the target IAB donor CU-UP are the forwarding tunnel identification information allocated on the Xn interface for different bearers of the UE.

Step 204: The target IAB donor CU-CP executes the Bearer Context Setup process corresponding to switching the IAB node MT.

The specific ones include:

1. The target IAB donor CU-CP sends a Bearer Context Setup Request message to the target IAB donor CU-UP. Optionally, the message includes, but is not limited to, the NG interface tunnel identification information allocated by the UPF to switch the different bearers of the IAB node MT.

2. The target IAB donor CU-UP sends a Bearer Context Setup Response message to the target IAB donor CU-CP. Optionally, the message includes at least one of the following information: the target IAB donor CU-UP is the different bearer of the switch IAB node MT tunnel identification information allocated on the NG interface, and the target IAB donor CU-UP is the difference between the switch IAB node MT The identification information of the tunnel that bears the allocation on the F1 interface, and the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface for the different bearers of the switch IAB node MT.

It should be noted that the order of step 203 and step 204 is not limited. In addition, the target IAB donor CU-UP in step 203 provides services for the UE, the target IAB donor CU-UP in step 204 provides services for handover IAB node MT, and the target IAB donor in step 203 and step 204 CU-UP can be the same or different.

Step 205: The target IAB donor CU-CP sends a UE Context Setup Request message to the target IAB donor DU.

Optionally, this message can be used to instruct the target IAB donor DU to establish a context for switching the IAB node MT.

Step 206: The target IAB donor DU sends a UE Context Setup Response message to the target IAB donor CU-CP.

With reference to Fig. 2 and Fig. 6 (or Fig. 7), Fig. 8 is a schematic flow chart of the handover process provided in an embodiment of the application.

Step 301: The target IAB donor CU-CP sends a Handover Request Acknowledge (Handover Request Acknowledge) message to the source IAB donor CU-CP.

With reference to Figure 6, the message includes at least one of the following information: the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface for different bearers of the UE, the configuration information of the UE, and the target IAB donor CU-UP is the handover IAB The different bearers of the node MT forward the tunnel identification information allocated on the Xn interface and switch the air interface configuration information of the IAB node MT.

That is to say, the target IAB donor CU-CP can use the Handover Request Acknowledge message to forward the forwarding tunnel identification information allocated by the target IAB donor CU-UP for the UE and the IAB node MT on the Xn interface to the source IAB donor CU- CP.

With reference to Figure 7, for the UE and the IAB node MT, the target IAB donor CU-CP sends different handover request confirmation messages to the source IAB donor CU-CP respectively. Among them, for the UE, the handover request confirmation message sent by the target IAB donor CU-CP to the source IAB donor CU-CP contains at least one of the following information: The target IAB donor CU-UP is the forwarding tunnel allocated on the Xn interface for different bearers of the UE Identification information, UE configuration information. For the IAB node MT, the handover request confirmation message sent by the target IAB donor CU-CP to the source IAB donor CU-CP contains at least one of the following information: The target IAB donor CU-UP is used to switch the different bearers of the IAB node MT allocated on the Xn interface Forward the tunnel identification information and switch the air interface configuration information of the IAB node MT.

Optionally, the configuration information of the UE includes at least one of the following information: the new security algorithm, the Next Hop Chaining Count (NCC) value corresponding to the air interface key, and the packet data convergence protocol (Packet Data Convergence Protocol) corresponding to different bearers of the UE. Data Convergence Protocol, PDCP) layer configuration, etc. Among them, the configuration information of the UE may be carried in a radio resource control reconfiguration (Radio Resource Control Reconfiguration, RRC Reconfiguration) message, or other RRC messages. That is, the RRCReconfiguration message or other RRC messages that carry UE configuration information are used as an RRC container and are carried in the handover request confirmation message.

Optionally, the air interface configuration information of the switching IAB node MT includes at least one of the following information: the configuration of the PDCP/RLC/MAC/PHY layer corresponding to different bearers of the switching IAB node MT, the configuration of the logical channel LCH, and the corresponding information of the new air interface key. NCC value, new security algorithm, etc. Among them, the air interface configuration for switching the IAB node MT can be carried in the RRCReconfiguration message or other RRC messages. That is, the RRCReconfiguration message or other RRC messages that carry the air interface configuration information of the handover IAB node MT are used as an RRC container and carried in the handover request confirmation message.

In an example, the Handover Request Acknowledge message may be the Handover Request Acknowledge message defined in the existing 3GPP standard. In another example, the Handover Request Acknowledge message may also be a newly defined XnAP message, which is not limited in this application.

Step 302: The source IAB donor CU-CP sends a UE Context Modification Request (UE Context Modification Request) message to the handover IAB node DU.

Optionally, the UE Context Modification Request message includes at least one of the following information: UE configuration information and Transmission Action Indicator IE, which is used to instruct the IAB node DU to stop data transmission with the UE. , And stop sending data to the source IAB donor CU-UP.

Step 303: The handover IAB node DU sends an RRCReconfiguration message to the UE, which carries the configuration information of the UE so that the UE can update according to the configuration of the target IAB donor CU-CP. That is, after receiving the RRCReconfiguration message, the UE can update the local configuration based on the new configuration included in it.

It should be noted that because the handover IAB node switches from the source IAB donor to the target IAB donor, the host node that provides services for the UE also changes from the source IAB donor to the target IAB donor. Although the UE is always attached to the same cell where the IAB node DU is handed over before and after the handover of the IAB node, due to the change of the host node, the PDCP layer configuration or security algorithm or security key of the UE needs to be updated. This process can be called The UE configuration update or UE handover is not limited in this application.

Step 304: The handover IAB node DU sends a UE Context Modification Response (UE Context Modification Response) message to the source IAB donor CU-CP.

Step 305: The source IAB donor CU-CP sends a Bearer Context Modification Request (Bearer Context Modification Request) message to the source IAB donor CU-UP.

Optionally, the message includes but is not limited to: the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface for different bearers of the UE, used for the source IAB donor CU-UP to establish the slave IAB donor for different bearers of the UE CU-UP to the target IAB donor CU-UP corresponding GTP forwarding tunnel.

Step 306: The source IAB donor CU-UP sends a Bearer Context Modification Response (Bearer Context Modification Response) message to the source IAB donor CU-CP.

Optionally, the message includes but is not limited to: PDCP status information corresponding to different bearers of the UE, for example: in the downlink direction, the count (COUNT) value allocated to the next PDCP service data unit (Service Data Unit, SDU) ( The COUNT value is composed of PDCP SN (Sequence Number) and HFN (Hyper Frame Number)), or the PDCP SN value assigned to the next PDCP SDU, and the first PDCP missing in the upstream direction The COUNT value or PDCP SN value corresponding to the SDU, and the reception status of each PDCP SDU starting from the first missing PDCP SDU.

Step 307: The source IAB donor CU-CP sends a sequence number status transfer (SN Status Transfer) message to the target IAB donor CU-CP.

Optionally, the message includes but is not limited to: PDCP status information corresponding to different bearers of the UE on the source IAB donor CU-UP. That is to say, the source IAB donor CU-CP sends the status information of the PDCP corresponding to the different bearers of the UE received from the source IAB donor CU-UP to the target IAB donor CU-CP through the SN Status Transfer message.

Step 308: The target IAB donor CU-CP sends a Bearer Context Modification Request message to the target IAB donor CU-UP, and the message includes the PDCP status information corresponding to different UEs on the source IAB donor CU-UP.

Step 309: The target IAB donor CU-UP sends a Bearer Context Modification Response message to the target IAB donor CU-CP.

It should be noted that steps 305 to 309 can be understood as when the UE switches to the target IAB donor, but the source IAB donor CU-UP may still have the UE data, for example: it has been sent to the UE but the UE has not received it correctly. Feedback data, or data that has not yet been sent to the UE. Therefore, in order to ensure the lossless data reception of the UE, the source IAB donor CU-UP needs to forward these UE data to the target IAB donor CU-UP through the forwarding tunnel, and the target IAB The donor CU-UP is further sent to the UE. Specifically, after step 309, the source IAB donor CU-UP can establish a GTP forwarding tunnel from the source IAB donor CU-UP to the target IAB donor CU-UP for the different bearers of the UE in step 305, and then to the target IAB donor CU-UP. UP forwards UE data.

Step 310: The UE sends an RRCReconfigurationComplete message to the handover IAB node DU.

In an example, the UE may validate the new configuration received in step 303 after sending the RRCReconfigurationComplete message. That is, based on the configuration used before step 303, the UE performs security processing on the RRCReconfigurationComplete message and sends it. In other words, the UE uses the security algorithm and key equivalent to the source IAB donor CU-CP to perform security processing on the RRCReconfigurationComplete message and then sends it to the handover IAB node DU, and the handover IAB node DU carries the received RRCReconfigurationComplete message as a container. The F1AP message is sent to the source IAB donor CU-CP. The source IAB donor CU-CP extracts the container from the F1AP message, and the container is carried in the XnAP message and sent to the target IAB donor CU-CP.

In another example, the UE may perform security processing on the RRCReconfigurationComplete message based on the new configuration received in step 303 and then send it, for example, using a new security algorithm and key to encrypt the RRCReconfigurationComplete message. There are two specific methods.

In method 1, after the handover IAB node DU receives the RRCReconfigurationComplete message, it can send the RRCReconfigurationComplete message to the target IAB donor CU-CP through the source IAB donor CU-CP, as shown in steps 311 to 312 in the figure. The protocol stack corresponding to the method is shown in Figure 9.

In the second method, after the handover IAB node DU receives the RRCReconfigurationComplete message, the message can be cached locally. The switch IAB node DU can switch to the target IAB donor in the corresponding switch IAB node MT, and after the F1 interface is established between the switch IAB node DU and the target IAB donor CU-CP, the RRCReconfigurationComplete message can be sent to the target IAB donor CU-CP . As shown in step 311' to step 312' in the figure, the protocol stack corresponding to this transmission mode is shown in figure 10.

Optionally, step 310 may be performed directly after step 303. The order of step 302 and step 305 is not limited, and is not limited in this application.

Step 311: Switch the IAB node DU to send an uplink RRC message transfer (UL RRC Message Transfer) message to the source IAB donor CU-CP.

Optionally, the RRCReconfigurationComplete message may be carried in the UL RRC Message Transfer message.

Step 312: The source IAB donor CU-CP sends an XnAP message to the target IAB donor CU-CP.

Optionally, the RRCReconfigurationComplete message may be carried in an XnAP message. The XnAP message may be a newly defined XnAP message, or the XnAP message may be an existing XnAP message, which is not limited in this application.

Step 313: The target IAB donor CU-CP triggers the path switch process of the UE to the AMF, and triggers the UE context release process to the source IAB donor CU-CP.

The specific steps of the path switch process and the UE context release process are not shown in the figure, and the path switch process may include:

1. The target IAB donor CU-CP sends the tunnel identification information allocated by the target IAB donor CU-UP on the NG interface to the UPF for different bearers of the UE, which is used to establish the UPF to the target IAB donor CU-UP for the different bearers of the UE. Corresponding downlink GTP tunnel.

2. The UPF sends an End Marker packet to the source IAB donor CU-UP to notify the source IAB donor that the CU-UP is currently the last packet received from the UPF.

3. UPF sends new data to the target IAB donor CU-UP. Specifically, the UPF may establish a downlink GTP tunnel corresponding to the target IAB donor CU-UP from the UPF to the target IAB donor CU-UP based on the different bearers of the UE, and send the new data of the UE to the target IAB donor CU-UP.

The UE context release procedure may include:

1. The target IAB donor CU-CP sends a UE Context Release (UE Context Release) message to the source IAB donor CU-CP to instruct the source IAB donor CU-CP to trigger the UE context deletion process.

2. The source IAB donor CU-CP sends a Bearer Context Release Command message to the source IAB donor CU-UP to instruct the source IAB donor CU-UP to delete the context of the UE.

3. The source IAB donor CU-UP sends a Bearer Context Release Complete message to the source IAB donor CU-CP to indicate that the source IAB donor CU-UP has successfully deleted the context of the UE.

Step 311', switch the IAB node DU and send the UL RRC Message Transfer message to the target IAB donor CU-CP.

Step 312' is the same as step 313, and will not be repeated here.

After the source IAB donor CU-CP sends the configuration information of the UE to the UE, it can trigger the handover process of the IAB node MT. specific:

Step 314: The source IAB donor CU-CP sends a UE Context Modification Request message to the source IAB donor DU.

Optionally, the message includes but is not limited to: RRCReconfiguration message for handover IAB node MT. Among them, the RRCReconfiguration message includes the new air interface configuration for switching the IAB node MT, which is used to instruct the IAB node MT to switch to the target IAB donor, and to update the local configuration according to the new air interface configuration.

Optionally, step 314 may be performed after 302, that is, after the source IAB donor CU-CP sends a UE Context Modification Request message to the handover IAB node DU, step 314 may be performed. Alternatively, step 314 may be performed after 304, that is, after the source IAB donor CU-CP receives the UE Context Modification Response message sent by the handover IAB node DU, step 314 may be performed. This application is not limited.

Step 315: The source IAB donor DU sends an RRCReconfiguration message to the handover IAB node MT. After the handover IAB node MT receives the RRCReconfiguration message, it executes the handover process. That is: update the local configuration according to the received new air interface configuration, and initiate random access to the target IAB donor.

Optionally, the source IAB donor CU-UP may also send the PDCP status information of the switching IAB node MT to the target IAB donor CU-UP, which specifically includes steps 316 to 321:

Step 316: The source IAB donor CU-CP sends a Bearer Context Modification Request message to the source IAB donor CU-UP.

Optionally, the message includes but is not limited to: the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface to switch the different bearers of the IAB node MT, used for the source IAB donor CU-UP to switch the IAB node MT Different bearers establish GTP forwarding tunnels corresponding to the source IAB donor CU-UP to the target IAB donor CU-UP.

Step 317: The source IAB donor CU-UP sends a Bearer Context Modification Response message to the source IAB donor CU-CP.

Optionally, the message includes but is not limited to: switch the status information of PDCP corresponding to different bearers of IAB node MT. Specifically, the PDCP status information is consistent with the description in step 306, and will not be repeated here.

Step 318: The source IAB donor CU-CP sends an SN Status Transfer message to the target IAB donor CU-CP.

Optionally, the message includes but is not limited to: status information of the PDCP corresponding to different bearers of the source IAB donor CU-UP to switch the IAB node MT.

Step 319: The target IAB donor CU-CP sends a Bearer Context Modification Request message to the target IAB donor UP, and the message includes the status information of the PDCP corresponding to the different bearers of the source IAB donor CU-UP to switch the IAB node MT.

Step 320: The target IAB donor CU-UP sends a Bearer Context Modification Response message to the target IAB donor CU-CP.

Step 321: The source IAB donor CU-UP forwards the IAB node MT data to the target IAB donor CU-UP through the forwarding tunnel.

Step 322: Switch the IAB node MT and send an RRC Reconfiguration Complete message to the target IAB donor DU.

Step 323: The target IAB donor DU sends a UL RRC Message Transfer message to the target IAB donor CU-CP, and the message carries the RRC Reconfiguration Complete message received from the handover IAB node MT.

In step 324, the target IAB donor CU-CP triggers the path switch process of switching the IAB node MT to the AMF, and triggers the context release process of switching the IAB node to the source IAB donor CU-CP.

It should be noted that the steps for handover of IAB node MT handover are similar to those during UE handover. For details, please refer to step 302 to step 314.

Step 325: Switching the IAB node DU triggers the F1 interface establishment process to the target IAB donor CU-CP.

Specifically, the switching IAB node MT notifies the switching IAB node DU through the internal interface, and it has successfully switched to the target IAB donor CU-CP, so as to trigger the switching IAB node DU to request the establishment process of the F1 interface from the target IAB donor CU-CP.

It should be noted that before switching the IAB node DU triggers the F1 interface establishment process to the target IAB donor CU-CP, the following additional operations are required:

Operation 1: Switching the IAB node DU needs to obtain the IP address information of the target IAB donor CU-CP.

In an example, during the handover preparation process, the IP address information of the target IAB donor CU-CP can be sent to the handover IAB node DU through the source IAB donor CU-CP. For example, it is carried in the Handover Request Acknowledge message in step 301 and the UE Context Modification Request message in step 302. Or, it is carried in other messages in the handover preparation process, which is not limited in this application.

In another example, during the handover preparation process, the IP address information of the target IAB donor CU-CP can be sent to the switching IAB node MT through the source IAB donor CU-CP, and then the switching IAB node MT is sent to the switching IAB node through the internal interface DU. For example, it is carried in the Handover Request Acknowledge message in step 301, the UE Context Modification Request message in step 314, and the RRCReconfiguration message in step 315. Or, it is carried in other messages in the handover preparation process, which is not limited in this application.

In another example, after the switch IAB node DU accesses the target IAB donor, the target IAB donor CU-CP carries its IP address information in the RRC message and sends it to the switch IAB node MT, which is then sent to the switch IAB node MT through the internal interface Switch IAB node DU.

Operation 2: Switch the IAB node DU and the target IAB donor CU-CP to establish a Stream Control Transmission Protocol (SCTP) association.

Before switching the IAB node DU and the target IAB donor CU-CP to establish an F1 interface, it is necessary to establish an SCTP association. Because the F1AP message transmitted on the F1 interface is transmitted through the SCTP association.

Operation 3: Switch IAB node DU to obtain new configuration information.

The new configuration information of the handover IAB node DU includes but is not limited to: the new cell global identity CGI of at least one cell served by the handover IAB node DU. Among them, there may be multiple serving cells for switching the IAB node DU, and the new configuration information contains multiple CGIs, and different cells correspond to different CGIs.

Specifically, there are two solutions for switching IAB node DU to obtain new configuration information:

1. After switching the IAB node DU to the target IAB donor, the target IAB donor obtains the new configuration information from the OAM server, or the switching IAB node DU can also obtain the new configuration information in other ways, and this application does not restrict it.

After obtaining the new configuration information, the handover IAB node DU sends the first indication information to the target IAB donor CU-CP. The first indication information includes the new CGI and the corresponding old CGI of the at least one cell served by the handover IAB node DU. Optionally, the first indication information may also include information indicating whether at least one cell served by the handover IAB node DU is activated, so that the target IAB donor CU-CP learns which of the cells served by the handover IAB node DU have been activated. Exemplarily, the first indication information may be carried in an F1 interface setup request message (F1Setup Request) or other F1AP messages, which is not limited in this application. Optionally, the indication information indicating whether at least one cell served by the IAB node DU is activated may be a displayed indication or an implicit indication. If it is an implicit instruction, as another example, after acquiring the new configuration information, switch the IAB node DU to send the first instruction information to the target IAB donor CU-CP, and the first instruction information includes the switch IAB node DU service The new CGI and the corresponding old CGI of at least one activated cell, and/or the new CGI and the corresponding old CGI of at least one inactive cell served by the IAB node DU.

2. During the handover preparation process, the handover IAB node DU obtains the new configuration information from the target IAB donor CU-CP through the source IAB donor CU-CP.

In order to help the target IAB donor CU-CP allocate new configuration information for the handover IAB node DU, the source IAB donor CU-CP needs to send the context information of the handover IAB node DU to the target IAB donor CU-CP during the handover preparation process. Among them, the context information of switching the IAB node DU has been described in step 101, and will not be repeated here.

Optionally, after obtaining the new configuration information, the new configuration information includes a new cell global identity CGI for switching at least one cell served by the IAB node DU. The handover IAB node DU sends first indication information to the target IAB donor CU-CP, where the first indication information includes the new CGI and the corresponding old CGI of the at least one cell served by the handover IAB node DU.

Optionally, switching the IAB node DU to obtain new configuration information from the target IAB donor CU-CP through the source IAB donor CU-CP may also include switching the new CGI and the corresponding old CGI of at least one cell served by the IAB node DU.

Step 326: UE's context establishment process.

It is worth noting that switching the IAB node DU triggers the F1 interface establishment process with the target IAB donor CU-CP, which will cause the switching IAB node DU to delete the UE's application layer context on the F1 interface. For example: switching IAB node DU to delete the F1AP ID of the UE on the F1 interface, and/or switching IAB node DU to delete the GTP tunnel of the per UE bearer allocated on the F1 interface, etc. Therefore, once the F1 interface is established between the handover IAB node DU and the target IAB donor CU-CP, the target IAB donor CU-CP needs to switch to the IAB node DU to trigger the context establishment process of the UE.

There may be multiple child node UEs for switching the IAB node DU. In order for the switching IAB node DU to recognize which UE establishes the context, there are two possible solutions.

1. During the handover preparation process, the target IAB donor CU-CP obtains the identity of the UE from the source IAB donor CU-CP, that is, the old CGI and C-RNTI. Among them, the old CGI is the identifier of the cell served by the handover IAB node DU to which the UE is attached. At this time, the cell served by the handover IAB node DU belongs to the source IAB donor. C-RNTI is the identifier assigned to the UE by the cell served by the IAB node DU to which the UE is attached.

After the handover is completed, the handover IAB node DU obtains the new configuration information, and the identity of the cell served by the handover IAB node DU to which the UE is attached is updated from the old CGI to the new CGI. At the same time, the UE’s identity is updated from the old CGI and C-RNTI Update to new CGI and C-RNTI. Then, the handover IAB node DU triggers the F1 interface establishment process with the target IAB donor CU-CP (that is, step 325), the handover IAB node DU sends the cell identification change information to the target IAB donor CU-CP, and the change information includes the handover IAB node DU Old CGI and corresponding new CGI of all cells. The target IAB donor CU-CP updates the cached UE identification information according to the received information, that is, updates the old CGI and C-RNTI to the new CGI and C-RNTI.

The target IAB donor CU-CP carries the updated UE identification information (new CGI+C-RNTI) in the UE Context Setup Request message and sends it to the handover IAB node DU. The handover IAB node DU can identify the UE attached to it according to the received new CGI and C-RNTI information.

2. The target IAB donor CU-CP sends a UE Context Setup Request message to the handover IAB node DU, and the UE Context Setup Request message carries the identification information of the UE (old CGI and C-RNTI). Switch IAB node DU to identify the UE according to the UE's identification information, and update the UE's identification according to the new configuration information obtained, for example: update the old CGI and C-RNTI to the new CGI and C-RNTI, and update the UE identification (New CGI and C-RNTI) are carried in the UE Context Setup Response message and sent to the target IAB donor CU-CP, and the target IAB donor CU-CP updates the identification information of the UE according to the received message.

In this application, before the handover, the source IAB donor CU-UP serving the UE and the source IAB donor CU-UP serving the handover IAB node MT may be the same or different. After the handover, the target IAB donor CU-UP serving the UE and the target IAB donor CU-UP serving the handover IAB node MT may also be the same or different, which is not limited in this application.

Optionally, in this application, the identification information of the UE can be in the form of CGI and C-RNTI, and the identification information of the F1 interface (which can be referred to as UE F1AP ID) can also be allocated to the UE through the IAB donor CU-CP. Identify the UE. In other words, the identifier of the F1 interface assigned by the IAB donor CU-CP to the UE is unique on the IAB donor CU-CP, and the IAB donor CU-CP can identify the corresponding UE based on the UE F1AP ID.

Specifically, in the embodiment that uses the UE F1AP ID to identify the UE, the pre-handover preparation process is similar to that in Figure 6 or Figure 7, except that the source IAB donor CU-CP does not need to send to the target IAB donor CU-CP UE's identification information (CGI and C-RNTI). In addition, in the process of handover preparation, the target IAB donor CU-CP sends the UE F1AP ID allocated to the UE to the handover IAB node DU through the source IAB donor CU-CP. Optionally, the UE F1AP ID can be carried in any message in the handover preparation process, which is not limited in this application.

After the handover of the IAB node MT is completed, the handover IAB node MT sends the F1AP message to the target IAB donor CU-CP. Optionally, the message includes but is not limited to: the RRCReconfigurationComplete message of the UE and the F1 tunnel identification information (UE F1AP ID) allocated by the target IAB donor CU-CP for the UE. That is, the handover IAB node MT forwards the UE's RRCReconfigurationComplete message to the target IAB donor CU-CP through the F1AP message. The target IAB donor CU-CP can identify which UE it is based on the received UE F1AP ID, and match it with the UE context obtained from the source IAB donor CU-CP during the handover preparation process.

It should be noted that this identification method (that is, the identification information of the F1 interface is used to identify the UE) can also be applied to the embodiments of Scheme 2 and Scheme 3. In order to avoid repetitive description, it will not be described in detail below.

Option II

With reference to FIG. 5, FIG. 11 is a schematic flowchart of a handover method provided in an embodiment of the application. In FIG. 11:

Step 401: The source IAB donor CU-CP sends a Handover Request to the target IAB donor CU-CP.

Optionally, the message includes at least one of the following information: UE context and UE identification information. This message can be used to inform the target IAB donor CU-CP that it is ready to handover the UE attached to the handover IAB node DU cell to the target IAB donor.

For other details, please refer to step 101, which will not be repeated here.

Step 402, Bearer Context Setup process.

Specifically, the target IAB donor CU-CP sends a Bearer Context Setup Request message to the target IAB donor CU-UP. Optionally, the message includes but is not limited to: NG interface tunnel identification information allocated by the UPF for different bearers of the UE.

Next, the target IAB donor CU-UP sends a Bearer Context Setup Response message to the target IAB donor CU-CP. Optionally, the message includes at least one of the following information: the target IAB donor CU-UP is the tunnel identification information allocated on the NG interface for the different bearers of the UE, and the target IAB donor CU-UP is the tunnel identification information allocated on the F1 interface for the different bearers of the UE. The tunnel identification information and the target IAB donor CU-UP are the forwarding tunnel identification information allocated on the Xn interface for different bearers of the UE.

For other details, please refer to step 102 and step 103, which will not be repeated here.

Step 404: The target IAB donor CU-CP sends a Handover Request Acknowledge message to the source IAB donor CU-CP.

Optionally, the message includes at least one of the following information: the target IAB donor CU-UP is forwarding tunnel identification information allocated on the Xn interface for different bearers of the UE, and configuration information of the UE. Among them, the configuration information of the UE may be carried in the RRCReconfiguration message or other RRC messages.

For other details, refer to step 301, which will not be repeated here.

Step 405: The source IAB donor CU-CP sends a UE Context Modification Request message to the handover IAB node DU.

Optionally, the UE Context Modification Request message includes at least one of the following information: UE configuration information and transmission action indicator information (Transmission Action Indicator IE).

For other details, refer to step 302, which will not be repeated here.

Step 406: The handover IAB node DU sends an RRCReconfiguration message to the UE, which carries the configuration information of the UE, so that the UE can update according to the configuration of the target IAB donor CU-CP. That is, after the UE receives the RRCReconfiguration message, it can update the local configuration based on the new configuration included in it.

Step 407: Switch the IAB node DU and send the UE Context Modification Response message to the source IAB donor CU-CP.

Step 408: Execute the Bearer Context Modification process.

Specifically, the source IAB donor CU-CP sends a Bearer Context Modification Request message to the source IAB donor CU-UP. Optionally, the message includes but is not limited to: the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface for different bearers of the UE, used for the source IAB donor CU-UP to establish the slave IAB donor for different bearers of the UE CU-UP to the target IAB donor CU-UP corresponding GTP forwarding tunnel.

Subsequently, the source IAB donor CU-UP sends a Bearer Context Modification Response message to the source IAB donor CU-CP. Optionally, the message includes but is not limited to: PDCP status information corresponding to different bearers of the UE.

For specific details, please refer to step 304 to step 306, which will not be repeated here.

Step 409: The source IAB donor CU-CP sends an SN Status Transfer message to the target IAB donor CU-CP. Optionally, the message includes but is not limited to: PDCP status information corresponding to different bearers of the UE on the source IAB donor CU-UP.

For other details, refer to step 307, which will not be repeated here.

Step 410, the target IAB donor CU-CP executes the Bearer Context Modification process.

Specifically, the target IAB donor CU-CP sends a Bearer Context Modification Request message to the target IAB donor CU-UP. The message includes but is not limited to the PDCP status information corresponding to different bearers of the UE on the source IAB donor CU-UP.

Next, the target IAB donor CU-UP sends a Bearer Context Modification Response message to the target IAB donor CU-CP.

For specific details, please refer to step 308 to step 309, which will not be repeated here.

Step 411: The source IAB donor CU-UP forwards the UE data to the target IAB donor CU-UP through the forwarding tunnel.

Step 412: The UE sends an RRCReconfigurationComplete message to the handover IAB node DU.

Specifically, the UE uses the security algorithm and key equivalent to the source IAB donor CU-CP to securely process the RRCReconfigurationComplete message, and then sends the RRCReconfigurationComplete message to the target IAB donor CU-CP through the source IAB donor CU-CP. For specific details, please refer to step 311, which will not be repeated here.

Alternatively, the UE may perform security processing on the RRCReconfigurationComplete message based on the received new configuration, for example, use a new security algorithm and key to encrypt the RRCReconfigurationComplete message. Same as solution 1, after the handover IAB node DU receives the RRCReconfigurationComplete message, in an example, the handover IAB node DU can send the RRCReconfigurationComplete message to the target IAB donor CU-CP through the source IAB donor CU-CP, as shown in step 413 in the figure. ~ As shown in step 415. In another example, to switch the IAB node DU, the RRCReconfigurationComplete message can be cached locally. The switch IAB node DU can switch to the target IAB donor in the corresponding switch IAB node MT, and after the F1 interface is established between the switch IAB node DU and the target IAB donor CU-CP, the RRCReconfigurationComplete message can be sent to the target IAB donor CU-CP . As shown in step 413' to step 414' in the figure.

Step 413: Switch the IAB node DU and send the UL RRC Message Transfer message to the source IAB donor CU-CP.

The RRCReconfigurationComplete message may be carried in the UL RRC Message Transfer message.

Step 414: The source IAB donor CU-CP sends an XnAP message to the target IAB donor CU-CP.

The RRCReconfigurationComplete message may be carried in an XnAP message.

Step 415, the target IAB donor CU-CP triggers the path switch process of the UE to the AMF, and triggers the UE context release process to the source IAB donor CU-CP.

For specific details, refer to step 314, which will not be repeated here.

Step 413', the handover IAB node DU sends a UL RRC Message Transfer message to the target IAB donor CU-CP. Optionally, the RRCReconfigurationComplete message may be carried in the UL RRC Message Transfer message.

Step 414', the target IAB donor CU-CP triggers the path switch process of the UE to the AMF.

For specific details, please refer to step 312 to step 314, which will not be repeated here.

Step 416: Perform the process of switching the IAB node MT to the target IAB donor.

1. The source IAB donor CU-CP sends a handover request message (Handover Request) to the target IAB donor CU-CP. The handover request message includes at least one of the following: context information for switching IAB node MT, identification information for switching IAB node MT, and context information for switching IAB node DU.

2. The target IAB donor CU-CP sends a Bearer Context Setup Request message to the target IAB donor CU-UP. Optionally, the message includes but is not limited to: NG interface tunnel identification information allocated by UPF to switch different bearers of IAB node MT.

3. The target IAB donor CU-UP sends a Bearer Context Setup Response message to the target IAB donor CU-CP. Optionally, the message includes at least one of the following information: the target IAB donor CU-UP is the switch IAB node MT tunnel identification information allocated on the NG interface, the target IAB donor CU-UP is the switch IAB node MT different bearer The tunnel identification information allocated on the F1 interface and the target IAB donor CU-UP are the forwarding tunnel identification information allocated on the Xn interface for switching different bearers of the IAB node MT.

4. The target IAB donor CU-CP sends a UE Context Setup Request message to the target IAB donor DU.

5. The target IAB donor DU sends a UE Context Setup Response message to the target IAB donor CU-CP.

6. The target IAB donor CU-CP sends a Handover Request Acknowledge message to the source IAB donor CU-CP. Optionally, the message includes at least one of the following information: the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface for different bearers of the switch IAB node MT, and the air interface configuration information of the switch IAB node MT.

7. The source IAB donor CU-CP sends a UE Context Modification Request message to the source IAB donor DU. Optionally, the message includes but is not limited to: RRCReconfiguration message for handover IAB node MT. Among them, the RRCReconfiguration message includes the new air interface configuration for switching the IAB node MT, which is used to instruct the IAB node MT to switch to the target IAB donor, and to update the local configuration according to the new air interface configuration.

8. The source IAB donor DU sends an RRCReconfiguration message to the handover IAB node MT. After the handover IAB node MT receives the RRCReconfiguration message, it executes the handover process. That is: update the local configuration according to the received new air interface configuration, and initiate random access to the target IAB donor.

9. The source IAB donor CU-CP sends the Bearer Context Modification Request message to the source IAB donor CU-UP. Optionally, the message includes but is not limited to: the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface to switch the different bearers of the IAB node MT, used for the source IAB donor CU-UP to switch the IAB node MT Different bearers establish GTP forwarding tunnels corresponding to the source IAB donor CU-UP to the target IAB donor CU-UP. Among them, step 7 and step 9 can be executed in parallel, and the order is not limited.

10. The source IAB donor CU-UP sends a Bearer Context Modification Response message to the source IAB donor CU-CP. Optionally, the message includes but is not limited to: switch the status information of PDCP corresponding to different bearers of IAB node MT.

11. The source IAB donor CU-CP sends the SN Status Transfer message to the target IAB donor CU-CP. Optionally, the message includes but is not limited to: status information of the PDCP corresponding to different bearers of the source IAB donor CU-UP to switch the IAB node MT.

12. The target IAB donor CU-CP sends a Bearer Context Modification Request message to the target IAB donor UP, which includes the status information of the PDCP corresponding to different bearers of the source IAB donor CU-UP to switch the IAB node MT.

13. The target IAB donor CU-UP sends a Bearer Context Modification Response message to the target IAB donor CU-CP.

14. The source IAB donor CU-UP forwards the IAB node MT data through the forwarding tunnel to the target IAB donor CU-UP.

15. The handover IAB node MT sends an RRC Reconfiguration Complete message to the target IAB donor DU.

16. The target IAB donor DU sends the UL RRC Message Transfer message to the target IAB donor CU-CP, which carries the RRC Reconfiguration Complete message received from the handover IAB node MT.

17. The target IAB donor CU-CP triggers the path switch process of switching IAB node MT to AMF, and triggers the context release process of switching IAB node to the source IAB donor CU-CP.

The preparation process before handover of IAB node MT and the handover process of handover of IAB node MT are similar to those of the UE. For specific details, please refer to the embodiment in solution 1, which will not be repeated here.

Step 417: Switching the IAB node DU triggers the F1 interface establishment process with the target IAB donor CU-CP.

For specific details, refer to step 325, which will not be repeated here.

Step 418, the UE's context establishment process.

For specific details, please refer to step 326, which will not be repeated here.

It should be noted that the difference between the second solution and the first solution is that: in this solution, the UE performs handover first, and then switches the IAB node before performing the handover. In solution 1, the UE and the handover IAB node perform the handover preparation process in parallel. After the handover IAB node sends the configuration information of the UE to the UE, the handover of the handover IAB node MT is performed.

third solution

Optionally, in this embodiment, the source IAB donor switches the handover IAB node MT to the target IAB donor, and then switches the UE attached to the handover IAB node DU cell to the target IAB donor. Among them, the switching process of switching IAB node MT can refer to the above, and it will not be repeated here.

Specifically, after switching the IAB node MT to the target IAB donor, and completing the F1 interface establishment process between the switching IAB node DU and the target IAB donor CU-CP, the target IAB donor CU-CP can obtain the services of the switching IAB node DU. The new cell identity (new CGI) and the corresponding old cell identity (old CGI) of at least one cell can be obtained by referring to Scheme 1, which will not be repeated here. Next, the target IAB donor CU-CP instructs the source IAB donor CU-CP to switch the identity change information of the cell served by the IAB node DU, and the information includes the CGI before and after the cell update (the new CGI and the corresponding old CGI). Exemplarily, the cell identity change information may be carried in a node configuration update (NG-RAN Node Configuration Update) message and sent by the target IAB donor CU-CP to the source IAB donor CU-CP.

The source IAB donor CU-CP can update the identification information of the UE, that is, update the identification information (old CGI and C-RNTI) of the UE to (new CGI and C-RNTI).

Then the UE executes the handover procedure, specifically:

As shown in FIG. 12, which exemplarily shows a schematic flowchart of a UE handover method, in FIG. 12:

Step 501: The source IAB donor CU-CP sends a Handover Request message to the target IAB donor CU-CP.

Optionally, the message includes at least one of the following information: identification information (new CGI and C-RNTI) of the UE and context information of the UE.

Step 502, Bearer Context Setup process.

Step 503: The target IAB donor CU-CP sends a Handover Request Acknowledge message to the source IAB donor CU-CP.

Optionally, the message includes but is not limited to: the target IAB donor CU-UP is the forwarding tunnel identification information allocated on the Xn interface for different bearers of the UE.

Step 504: Execute the Bearer Context Modification process.

Step 505: The source IAB donor CU-CP sends an SN Status Transfer message to the target IAB donor CU-CP. Optionally, the message includes but is not limited to: PDCP status information corresponding to different bearers of the UE on the source IAB donor CU-UP.

For other details, refer to step 307, which will not be repeated here.

Step 506, the target IAB donor CU-CP executes the Bearer Context Modification process.

Step 507: The source IAB donor CU-UP forwards the UE data to the target IAB donor CU-UP through the forwarding tunnel.

Step 508: Context establishment process of the UE.

Step 509: The target IAB donor CU-CP sends a UE Context Modification Request message to the handover IAB node DU.

Optionally, the UE Context Modification Request message includes new configuration information allocated by the target IAB donor CU-CP for the UE, and the new configuration information may be carried in the RRCReconfiguration message.

Step 510: Switch the IAB node DU to send an RRCReconfiguration message to the UE.

It should be noted that before the UE receives the new configuration sent by the target IAB donor CU-CP, the configuration information used by the UE is always allocated by the source IAB donor CU-CP, that is, the UE will only use the source IAB donor CU-CP The configured security algorithm and key perform security processing on sent/received RRC messages. Therefore, in order for the UE to safely parse the RRCReconfiguration message generated by the target IAB donor CU-CP, the target IAB donor CU-CP needs to use the security algorithm and key used by the source IAB donor CU-CP to securely process the message and send it. . That is, in step 601, the source IAB donor CU-CP also needs to send the security algorithm and key used by it to the target IAB donor CU-CP.

Step 511: The UE sends an RRCReconfigurationComplete message to the handover IAB node DU.

Step 512: Switch the IAB node DU and send the UL RRC Message Transfer message to the target IAB donor CU-CP.

Among them, the UL RRC Message Transfer message carries the RRCReconfigurationComplete message.

Step 513: The target IAB donor CU-CP triggers the path switch process of the UE to the AMF, and triggers the UE context release process to the source IAB donor CU-CP.

For specific details, please refer to Scheme 1 and Scheme 2, which will not be repeated here.

Optionally, as shown in Figure 5 is a two-hop backhaul link scenario, that is, the parent node of the switching IAB node is the source IAB donor, and the child node of the IAB node is switched to the UE as an example. For the multi-hop scenario, for example, Scenario two, that is, in the scenario shown in Figure 2, the handover process of switching between an IAB node and other IAB nodes attached to it and UEs attached to other IAB nodes may include: in the handover preparation process, the source IAB donor to the target The IAB donor sends topology information, where the topology information is used to describe the parent-child relationship between neighboring nodes, that is, the topology information can be used to instruct to switch the parent-child relationship between the IAB donor and the child nodes directly attached to it. It can also be used to indicate the parent-child relationship between child nodes. Exemplarily, in the scenario in FIG. 2, the topology information includes the parent-child relationship between switching IAB node and IAB node A, and the parent-child relationship between IAB node A and UE. Alternatively, the topology information includes the parent-child relationship between switching IAB node and IAB node A, the parent-child relationship between IAB node A and IAB node B, and the parent-child relationship between IAB node B and UE.

Optionally, the topology information can be carried in the Handover Request and sent to the target IAB donor together with the context information of the UE, the context information of other IAB nodes, and/or the context information of the handover IAB node.

Optionally, in a multi-hop scenario, the handover process of switching between an IAB node and other IAB nodes attached to it and UEs attached to other IAB nodes may also include: in the handover preparation process, the source IAB node to the target IAB donor Send at least one of the following information: UE context information, UE identification information, handover IAB node MT context information, handover IAB node MT identification information, handover IAB node DU context information, other IAB node MT context information, others IAB node MT identification information, other IAB node DU context information. Among them, the context information of the UE, the identification information of the UE, the context information of the handover IAB node MT, the identity information of the handover IAB node MT, and the context information of the handover IAB node DU are described in step 101 of the scheme 1, and will not be repeated here. . Among them, the context information of other IAB node MT is similar to the context information of handover IAB node MT, the identification information of other IAB node MT is similar to the identification information of handover IAB node MT, and the context information of other IAB node DU is similar to handover. The context information of IAB node DU will not be repeated here. For the handover steps of the IAB node (including handover of IAB nodes and other IAB nodes) and the UE in the multi-hop scenario, refer to Solution 1, Solution 2, or Solution 3, which will not be repeated here.

The foregoing mainly introduces the solution provided by the embodiment of the present application from the perspective of interaction between various network elements. It is understandable that in order to realize the above-mentioned functions, IAB donor and IAB node include hardware structures and/or software modules corresponding to each function. Those skilled in the art should easily realize that in combination with the units and algorithm steps of the examples described in the embodiments disclosed herein, the embodiments of the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed by hardware or computer software-driven hardware depends on the specific application and design constraint conditions of the technical solution. Professionals and technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered beyond the scope of this application.

The embodiment of the present application may divide the IAB donor and the IAB node into functional modules according to the foregoing method examples. For example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The above-mentioned integrated modules can be implemented in the form of hardware or software function modules. It should be noted that the division of modules in the embodiments of the present application is illustrative, and is only a logical function division, and there may be other division methods in actual implementation.

In an example, FIG. 13 shows a schematic diagram of a possible structure of the source IAB donor 100 involved in the foregoing embodiment. As shown in FIG. 13, the source IAB donor 100 may include: a receiving module 101, a determining module 102, and a sending module 103 . Wherein, the receiving module 101 can be used for the step of "acquiring signal quality information". For example, this module can be used for supporting the source IAB donor to execute step 101, step 202, step 401, and step 501 in the foregoing method embodiment. The determining module 102 can be used to "determine the step of switching the IAB node to the target IAB donor based on the measurement result". For example, this module can be used to support the source IAB donor to perform step 101, step 202, step 401, and step 401 in the above method embodiment. Step 501. The sending module 103 can be used for the step of "sending the context of the IAB node and the context of at least one child node of the IAB node to the target IAB donor". For example, this module can be used to support the source IAB donor to perform step 101 in the above method embodiment, Step 202, step 401, and step 501.

In an example, FIG. 14 shows a schematic diagram of a possible structure of the IAB node 200 involved in the foregoing embodiment. As shown in FIG. 14, the IAB node 200 may include: a sending module 201 and a receiving module 202. Wherein, the sending module 201 can be used for the step of “sending the measurement result to the source IAB donor”. For example, this module can be used for supporting the IAB node to execute step 101, step 202, step 401, and step 501 in the foregoing method embodiment. The receiving module 202 may be used for the step of "receiving the first configuration information required for the IAB node to switch to the target IAB donor from the source IAB donor and the second configuration information required for the at least one child node of the IAB node to switch to the target IAB donor", For example, this module can be used to support the IAB node to execute step 302, step 315, step 405, step 416, step 503, and step 509 in the foregoing method embodiment. The sending module 201 may also be used to “send the second configuration information to at least one child node”. For example, the module may be used to support the IAB node to perform step 303, step 406, and step 510 in the foregoing method embodiment.

The following describes a device provided by an embodiment of the present application. As shown in Figure 15:

The device includes a processing module 301 and a communication module 302. Optionally, the device further includes a storage module 303. The processing module 301, the communication module 302, and the storage module 303 are connected by a communication bus.

The communication module 302 may be a device with a transceiving function, and is used to communicate with other network equipment or a communication network.

The storage module 303 may include one or more memories, and the memories may be devices for storing programs or data in one or more devices or circuits.

The storage module 303 can exist independently and is connected to the processing module 301 through a communication bus. The storage module can also be integrated with the processing module 301.

The apparatus 300 can be used in a network device, a circuit, a hardware component, or a chip.

The device 300 may be an IAB node in the embodiment of the present application, for example, switching IAB node. Optionally, the communication module 302 of the device 300 may include an antenna and a transceiver of an IAB node. Optionally, the communication module 302 may also include an output device and an input device.

The device 300 may be a chip in the IAB node in the embodiment of the present application. The communication module 302 may be an input or output interface, pin or circuit, or the like. Optionally, the storage module may store a computer-executed instruction of the method on the IAB node side, so that the processing module 301 executes the method on the IAB node side in the foregoing embodiment. The storage module 303 can be a register, a cache or RAM, etc. The storage module 303 can be integrated with the processing module 301; the storage module 303 can be a ROM or other types of static storage devices that can store static information and instructions, and the storage module 303 can be integrated with the processing module 301. The processing module 301 is independent. Optionally, with the development of wireless communication technology, the transceiver may be integrated on the device 300, for example, the communication module 302 integrates the transceiver 202.

When the device 300 is the IAB node or the chip in the IAB node in the embodiment of the present application, the device 300 can implement the method for switching the execution of the IAB node in the foregoing embodiment.

The device 300 may be the IAB donor in the embodiment of the present application, for example, the source IAB donor and the target IAB donor. Optionally, the communication module 302 of the device 300 may include an antenna and a transceiver of an IAB donor. The communication module 302 may also include a network interface of the IAB donor.

The device 300 may be a chip in the IAB donor in the embodiment of the present application. The communication module 302 may be an input or output interface, pin or circuit, or the like. Optionally, the storage module may store a computer-executed instruction of the method on the source IAB donor side, so that the processing module 301 executes the method on the source IAB donor side in the foregoing embodiment. The storage module 303 can be a register, a cache or RAM, etc. The storage module 303 can be integrated with the processing module 301; the storage module 303 can be a ROM or other types of static storage devices that can store static information and instructions, and the storage module 303 can be integrated with the processing module 301. The processing module 301 is independent. Optionally, with the development of wireless communication technology, the transceiver may be integrated on the device 300, for example, the communication module 302 integrates the transceiver 103 and the network interface 104.

When the device 500 is the IAB donor in the embodiment of the present application or the chip in the IAB donor, the method executed by the IAB donor in the foregoing embodiment can be implemented.

Among them, all relevant content of the steps involved in the above method embodiments can be cited in the functional description of the corresponding functional module, which will not be repeated here.

Based on the same technical concept, the embodiments of the present application also provide a computer-readable storage medium, the computer-readable storage medium stores a computer program, the computer program includes at least one piece of code, the at least one piece of code can be executed by IAB node to control The IAB node is used to implement the above method embodiments.

Based on the same technical concept, the embodiments of the present application also provide a computer-readable storage medium, the computer-readable storage medium stores a computer program, the computer program includes at least one piece of code, the at least one piece of code can be executed by the IAB donor to control The IAB donor is used to implement the above method embodiments.

Based on the same technical concept, the embodiments of the present application also provide a computer program, which is used to implement the foregoing method embodiment when the computer program is executed by the IAB node.

Based on the same technical concept, the embodiment of the present application also provides a computer program, which is used to implement the above method embodiment when the computer program is executed by the IAB donor.

The program may be stored in whole or in part on a storage medium packaged with the processor, and may also be stored in part or in a memory not packaged with the processor.

Based on the same technical concept, an embodiment of the present application further provides a processor, which is configured to implement the foregoing method embodiment. The above-mentioned processor may be a chip.

The steps of the method or algorithm described in combination with the disclosure of the embodiments of the present application may be implemented in a hardware manner, or may be implemented in a manner in which a processor executes software instructions. Software instructions can be composed of corresponding software modules, which can be stored in random access memory (Random Access Memory, RAM), flash memory, read-only memory (Read Only Memory, ROM), and erasable programmable read-only memory ( Erasable Programmable ROM (EPROM), Electrically Erasable Programmable Read-Only Memory (Electrically EPROM, EEPROM), registers, hard disk, mobile hard disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, so that the processor can read information from the storage medium and can write information to the storage medium. Of course, the storage medium may also be an integral part of the processor. The processor and the storage medium may be located in the ASIC. In addition, the ASIC can be located in a network device. Of course, the processor and the storage medium may also exist as discrete components in the network device.

Those skilled in the art should be aware that, in one or more of the foregoing examples, the functions described in the embodiments of the present application may be implemented by hardware, software, firmware, or any combination thereof. When implemented by software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on the computer-readable medium. The computer-readable medium includes a computer storage medium and a communication medium, where the communication medium includes any medium that facilitates the transfer of a computer program from one place to another. The storage medium may be any available medium that can be accessed by a general-purpose or special-purpose computer.

The embodiments of the application are described above with reference to the accompanying drawings, but the application is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are only illustrative and not restrictive. Those of ordinary skill in the art are Under the enlightenment of this application, many forms can be made without departing from the purpose of this application and the scope of protection of the claims, all of which fall within the protection of this application.

Claims

A handover method, characterized in that it is applied to a source access backhaul integrated host IAB donor, and the method includes:

Receive the measurement result reported by the IAB node, where the measurement result includes at least one of the signal measurement result of the source cell and the signal measurement result of the target cell, wherein the source cell belongs to the source IAB donor, and the target cell belongs to Target IAB donor;

Based on the measurement result, it is determined to switch the IAB node to the target IAB donor, then the context information of the IAB node and the context information of at least one child node of the IAB node are sent to the target IAB donor; where At least one child node of the IAB node includes user equipment UE and/or other IAB nodes.
The method according to claim 1, wherein the method further comprises:

Receive the first configuration information required by the IAB node to switch to the target IAB donor from the target IAB donor, and the second configuration required by the at least one child node of the IAB node to switch to the target IAB donor information;

Sending the second configuration information to at least one child node of the IAB node, and sending the first configuration information to the IAB node.
The method according to claim 2, wherein if at least one child node of the IAB node includes a UE, the second configuration information includes at least one of the following:

The configuration information of the PDCP layer of the UE that is equivalent to the target IAB donor, the security algorithm used between the UE and the target IAB donor, and the security secret used between the UE and the target IAB donor The NCC value corresponding to the key.
The method according to any one of claims 1 to 3, wherein:

The context information of the IAB node and the context information of at least one child node of the IAB node are carried in the first message;

or,

The context information of the IAB node is carried in a first message, and the context information of at least one child node of the IAB node is carried in n second messages, and the n second messages are the same as the at least one child node. One correspondence, n is equal to the number of the at least one child node.
The method according to any one of claims 1 to 4, wherein if at least one child node of the IAB node includes a UE, the context information of the IAB node and the target IAB donor are sent to the target IAB donor. The context information of at least one child node of the IAB node also includes:

Sending the identification information of the UE to the target IAB donor;

The identification information includes the cell global identification CGI used by the UE to access the cell of the IAB node, and the cell radio network temporary identification C-RNTI of the UE in the cell of the IAB node.
The method according to any one of claims 1 to 5, characterized in that:

If at least one child node of the IAB node includes another IAB node, the context information of the other IAB node includes the context information of the distributed unit DU of the other IAB node;

The context information of the DU includes at least one of the following:

The identification information of the DU, the identification CGI of at least one cell served by the DU, the physical cell identification PCI of the at least one cell served by the DU, the RRC version supported by the DU, and the indication information of whether at least one cell served by the DU is activated.
The method according to any one of claims 1 to 6, wherein the sending context information of the IAB node and context information of at least one child node of the IAB node to the target IAB donor further comprises :

Send topology information to the target IAB donor, where the topology information is used to indicate a topology relationship between the IAB node and at least one child node of the IAB node and/or between multiple child nodes of the IAB node.
The method according to any one of claims 1 to 7, wherein the method further comprises:

Receiving a new cell global identity and an old cell global identity of at least one cell served by the DU of the IAB node sent by the target IAB donor;

Sending the new cell global identity and the old cell global identity of at least one cell served by the DU of the IAB node to the IAB node;

or,

Receiving the new cell global identity of at least one cell served by the DU of the IAB node sent by the target IAB donor;

Sending the new cell global identity of at least one cell served by the DU of the IAB node to the IAB node;

Wherein, the new cell global identifier is the cell global identifier used by the IAB node to switch to the target IAB donor; the old cell global identifier is the cell global identifier used by the IAB node to access the source IAB donor.
A handover method, which is characterized in that it is applied to access a turning integrated IAB node, and the method includes:

Sending the measurement result to the source IAB donor;

Receive the first configuration information required for the IAB node to switch to the target IAB donor and the second configuration information required for at least one child node of the IAB node to switch to the target IAB donor sent by the source IAB donor ; At least one child node of the IAB node includes user equipment UE and/or other IAB nodes;

Sending the second configuration information to the at least one child node.
The method according to claim 9, wherein the method further comprises:

Acquiring a new cell global identity CGI of at least one cell served by the DU of the IAB node;

The global identifier of the new cell is the global identifier of the cell used by the IAB node to switch to the target IAB donor; the global identifier of the old cell used by the IAB node to access the source IAB donor.
The method according to claim 10, wherein after the obtaining the new cell global identity of at least one cell served by the DU of the IAB node, the method further comprises:

Send an indication message to the target IAB donor, where the indication message includes the old cell global identity and the new cell global identity of at least one cell served by the DU.
The method according to claim 11, wherein the indication message further includes indication information of whether at least one cell served by the DU is activated.
The method according to claim 10, wherein if the at least one child node includes a UE, the method further comprises:

The IAB node switches to the target IAB donor, and receives the identification information of the UE sent by the target IAB donor;

Wherein, the identification information of the UE includes the old cell global identity of the cell served by the DU of the IAB node and the cell radio network temporary identity C-RNTI of the UE in the cell served by the DU;

or,

The identification information of the UE includes the global identity of the new cell of the cell served by the DU of the IAB node and the C-RNTI of the UE in the cell served by the DU.
The method according to any one of claims 9 to 13, wherein if the at least one child node includes a UE, before the IAB node switches to the target IAB donor, the method further comprises:

Receiving the identifier of the F1 interface allocated by the target IAB donor for the UE from the source IAB donor, where the F1 interface is an interface between the IAB node and the target IAB donor.
A handover device, characterized in that it is applied to a source access backhaul integrated host IAB donor, and the device includes:

A memory and a processor, the memory and the processor are coupled,

The memory stores program instructions, and when the program instructions are executed by the processor, the switching device executes the following steps:

Receive the measurement result reported by the IAB node, where the measurement result includes at least one of the signal measurement result of the source cell and the signal measurement result of the target cell, wherein the source cell belongs to the source IAB donor, and the target cell belongs to Target IAB donor;

Based on the measurement result, it is determined to switch the IAB node to the target IAB donor, then the context information of the IAB node and the context information of at least one child node of the IAB node are sent to the target IAB donor; where At least one child node of the IAB node includes user equipment UE and/or other IAB nodes.
The device according to claim 15, wherein when the program instructions are executed by the processor, the switching device executes the following steps:

Receive the first configuration information required by the IAB node to switch to the target IAB donor from the target IAB donor, and the second configuration required by the at least one child node of the IAB node to switch to the target IAB donor information;

Sending the second configuration information to at least one child node of the IAB node, and sending the first configuration information to the IAB node.
The apparatus according to claim 16, wherein if at least one child node of the IAB node includes a UE, the second configuration information includes at least one of the following:

The configuration information of the PDCP layer of the UE that is equivalent to the target IAB donor, the security algorithm used between the UE and the target IAB donor, and the security secret used between the UE and the target IAB donor The NCC value corresponding to the key.
The device according to any one of claims 15 to 17, wherein:

The context information of the IAB node and the context information of at least one child node of the IAB node are carried in the first message;

or,

The context information of the IAB node is carried in a first message, and the context information of at least one child node of the IAB node is carried in n second messages, and the n second messages are the same as the at least one child node. One correspondence, n is equal to the number of the at least one child node.
The apparatus according to any one of claims 15 to 18, wherein if at least one child node of the IAB node includes a UE, the context information and the context information of the IAB node are sent to the target IAB donor. The context information of at least one child node of the IAB node, when the program instructions are executed by the processor, cause the switching device to perform the following steps:

Sending the identification information of the UE to the target IAB donor;

The identification information includes the cell global identification CGI used by the UE to access the cell of the IAB node, and the cell radio network temporary identification C-RNTI of the UE in the cell of the IAB node.
The device according to any one of claims 15 to 19, characterized in that:

If at least one child node of the IAB node includes another IAB node, the context information of the other IAB node includes the context information of the distributed unit DU of the other IAB node;

The context information of the DU includes at least one of the following:

The identification information of the DU, the identification CGI of at least one cell served by the DU, the physical cell identification PCI of the at least one cell served by the DU, the RRC version supported by the DU, and the indication information of whether at least one cell served by the DU is activated.
The apparatus according to any one of claims 15 to 20, wherein the sending the context information of the IAB node and the context information of at least one child node of the IAB node to the target IAB donor, the When the program instructions are executed by the processor, the switching device executes the following steps:

Send topology information to the target IAB donor, where the topology information is used to indicate a topology relationship between the IAB node and at least one child node of the IAB node and/or between multiple child nodes of the IAB node.
The device according to any one of claims 15 to 21, wherein when the program instructions are executed by the processor, the switching device executes the following steps:

Receiving a new cell global identity and an old cell global identity of at least one cell served by the DU of the IAB node sent by the target IAB donor;

Sending the new cell global identity and the old cell global identity of at least one cell served by the DU of the IAB node to the IAB node;

or,

Receiving the new cell global identity of at least one cell served by the DU of the IAB node sent by the target IAB donor;

Sending the new cell global identity of at least one cell served by the DU of the IAB node to the IAB node;

Wherein, the new cell global identifier is the cell global identifier used by the IAB node to switch to the target IAB donor; the old cell global identifier is the cell global identifier used by the IAB node to access the source IAB donor.
A handover device, which is characterized in that it is applied to access a turn integrated IAB node, and the device includes:

A memory and a processor, the memory and the processor are coupled,

The memory stores program instructions, and when the program instructions are executed by the processor, the switching device executes the following steps:

Sending the measurement result to the source IAB donor;

Receive the first configuration information required for the IAB node to switch to the target IAB donor and the second configuration information required for at least one child node of the IAB node to switch to the target IAB donor sent by the source IAB donor ; At least one child node of the IAB node includes user equipment UE and/or other IAB nodes;

Sending the second configuration information to the at least one child node.
The device according to claim 23, wherein when the program instructions are executed by the processor, the switching device executes the following steps:

Acquiring a new cell global identity CGI of at least one cell served by the DU of the IAB node;

The global identifier of the new cell is the global identifier of the cell used by the IAB node to switch to the target IAB donor; the global identifier of the old cell used by the IAB node to access the source IAB donor.
The device according to claim 24, wherein when the program instructions are executed by the processor, the handover device, after acquiring the new cell global identity of at least one cell served by the DU of the IAB node, Perform the following steps:

Send an indication message to the target IAB donor, where the indication message includes the old cell global identity and the new cell global identity of at least one cell served by the DU.
The apparatus according to claim 25, wherein the indication message further includes indication information of whether at least one cell served by the DU is activated.
The device according to claim 24, wherein if the at least one child node includes a UE, when the program instructions are executed by the processor, the switching device is caused to perform the following steps:

The IAB node switches to the target IAB donor, and receives the identification information of the UE sent by the target IAB donor;

Wherein, the identification information of the UE includes the old cell global identity of the cell served by the DU of the IAB node and the cell radio network temporary identity C-RNTI of the UE in the cell served by the DU;

or,

The identification information of the UE includes the global identity of the new cell of the cell served by the DU of the IAB node and the C-RNTI of the UE in the cell served by the DU.
The apparatus according to any one of claims 23 to 27, wherein if the at least one child node includes a UE, before the IAB node switches to the target IAB donor, the program instructions are executed by the processor During operation, the switching device is caused to perform the following steps:

Receiving the identifier of the F1 interface allocated by the target IAB donor for the UE from the source IAB donor, where the F1 interface is an interface between the IAB node and the target IAB donor.
A handover system, characterized in that it includes a source access backhaul integrated host IAB donor, a target IAB donor, an IAB node, and at least one child node of the IAB node, wherein at least one child node of the IAB node includes User equipment UE and/or other IAB nodes;

The IAB node is configured to send a measurement result to the source IAB donor, where the measurement result includes at least one of the signal measurement result of the source cell and the signal measurement result of the target cell, wherein the source cell belongs to the Source IAB donor, the target cell belongs to the target IAB donor

The source IAB donor is used to determine to switch the IAB node to the target IAB donor based on the measurement result, and then send the context information of the IAB node and at least the IAB node to the target IAB donor Context information of a child node;

The target IAB donor is used to send, to the source IAB donor, what is needed for the IAB node to switch to the target IAB donor based on the context information of the IAB node and the context information of at least one child node of the IAB node The first configuration information of and the second configuration information required for at least one child node of the IAB node to switch to the target IAB donor;

The source IAB donor is also used to send the first configuration information and the second configuration information to the IAB node;

The IAB node is further configured to receive the first configuration information and the second configuration information, and send the second configuration information to the at least one child node.
A computer-readable storage medium, the computer-readable storage medium stores a computer program, the computer program includes at least one piece of code, the at least one piece of code can be executed by a source-accessed backhaul integrated host IAB donor to control all The IAB donor executes the method described in any one of claims 1 to 7.
A computer-readable storage medium, the computer-readable storage medium stores a computer program, the computer program includes at least one piece of code, the at least one piece of code can be executed by an integrated IAB node for access and return to control the IAB The node executes the method according to any one of claims 8 to 14.