Group migration method, apparatus and system

Abstract

This application provides a group migration method, apparatus, and system. The group migration method includes: when migrating an IAB node from a first Donor to a second Donor device, the second Donor device performs at least one of the following processes: causing the migrating IAB node to update a first TNL address of a first F1-C connection to a second TNL address; causing the migrating IAB node to update a third TNL address of a second F1-C connection to a fourth TNL address; configuring a fourth TNL address for establishing a second F1-C connection for the migrating IAB node; adding a second TNL address for the first F1-C connection to the migrating IAB node; configuring a third TNL address for establishing a second F1-C connection to the migrating IAB node; and adding a fourth TNL address for the second F1-C connection to the migrating IAB node.

Description

Technical Field

[0001] This application relates to the field of communications. Background Technology

[0002] The seamless deployment of future cellular networks requires highly flexible and ultra-dense NR cell deployments. Ultra-dense networks are one of the goals of 5G, and deploying an NR network that does not require wired backhaul is crucial for realizing ultra-dense 5G networks. Because 5G millimeter wave technology reduces cell coverage, the wireless self-backhaul system also needs to be multi-hop to meet deployment requirements. 5G's high bandwidth, massive MIMO, and beamforming systems make it easier to develop wireless self-backhaul systems for ultra-dense NR cells than LTE. To develop such a multi-hop system with wireless self-backhaul, 3GPP initiated the IAB (Integrated Access and Backhaul) project in Release 16 for research and standardization.

[0003] Figure 1 This is a schematic diagram of the IAB system, such as... Figure 1 As shown, in the IAB system, relay nodes support both access and backhaul functions. The wireless transmission links of relay nodes can reuse access links and backhaul links in the time domain, frequency domain, or spatial domain. Access links and backhaul links can use the same or different frequency bands.

[0004] In the IAB network architecture, the relay node refers to the IAB-node, which supports both access and backhaul functions. The last-hop access node on the network side is called the IAB-donnor, which supports gNB functionality and IAB-node access. All UE data can be backhauled to the IAB-donor via one or more hops through the IAB-node.

[0005] The IAB-node function is divided into two parts: one is the gNB-DU function, called IAB-DU, and the other is the UE function, called IAB-MT. The IAB-DU implements network-side equipment functions, connects to the downstream child IAB-node, provides NR air interface access to the UE and the downstream child IAB-node, and establishes an F1 connection with the IAB donor-CU. The IAB-MT implements some terminal equipment functions, connects to the upstream parent IAB-node or IAB-donor DU. The IAB-MT includes physical layer, layer 2, RRC (Radio Resource Control), and NAS (Non-Access Stratum) layer functions, and also indirectly connects to the IAB donor-CU and the core network (CN).

[0006] In the IAB system, IAB-nodes can access the network in either standalone (SA) or non-standalone (EN-DC, E-UTRA-NRDualConnectivity) mode. Figure 2 This is a schematic diagram of the IAB architecture in SA mode. Figure 3 This is a schematic diagram of the IAB architecture in EN-DC mode.

[0007] Figure 4 This is a diagram illustrating an IAB node (IAB-node), its parent node (parent IAB-node), and its child nodes (child IAB-node). For example... Figure 4 As shown, the IAB-DU of the IAB node is connected to the IAB-MT of the child node as the network side, and the IAB-MT of the IAB node is connected to the IAB-DU of the parent node as the terminal side.

[0008] Figure 5 This is a schematic diagram of the F1 user plane (F1-U) protocol stack between IAB-DU and IAB-donor CU. Figure 6 This is a schematic diagram of the F1 control plane (F1-C) protocol stack between IAB-DU and IAB-donor CU.

[0009] like Figure 5 and Figure 6 As shown, F1-U and F1-C are built on top of the transport (IP) layer between IAB-DU and IAB-donor-CU. Figure 5 and Figure 6The process involves two hops of wireless backhaul and one hop of wired backhaul. On the backhaul link, the transport (IP) layer is carried on the Backhaul Adaptive Protocol (BAP) sublayer. The BAP entity in the IAB-node implements the routing function of the IAB system, with the routing table provided by the IAB-donorCU. BAP PDUs (Protocol Data Units) are transmitted in the RLC (Radio Link Control) channels of the backhaul link. Multiple RLC channels of the backhaul link can be configured by the IAB-donor to carry services with different priorities and QoS (Quality of Service), and the BAP entity maps BAP PDUs to different backhaul RLC channels.

[0010] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0011] The inventors discovered that in R16, the IAB system already supports adaptive changes in topology and routing caused by the movement of an IAB-node between different DUs under the same Donor. When an IAB-node moves within the same Donor (at this time, the IAB-node is called the Migrating IAB-node), it maintains its topological relationship with downstream child IAB-nodes and UEs. Although the IAB-node accesses the Donor's CU via a new Donor's DU and may be assigned a TNL (Transport Network Layer) address, i.e., an IP address, that allows access to the new Donor's DU, the child nodes or UEs served by the Migrating IAB-node do not need to migrate. Therefore, the migrating node does not need to establish a new F1-C connection with the Donor. Figure 7 As shown, after Migrating IAB-node moves from IAB-node 1 to IAB-node 2, it simply updates or adds the transmission path for F1-C traffic; this process is called F1 redirection.

[0012] Furthermore, the inventors discovered that Release 17 (R17) will introduce the ability for IAB-nodes to move between different Donors. In this case, after an IAB-node connects to a new Donor, it becomes a DU (Distributed Unit) under the new Donor, serving its child IAB nodes or UEs. Therefore, it needs to establish an F1-C connection with the new Donor and migrate the child IAB nodes or UEs under the IAB-node to the new Donor to achieve load balancing among the donor devices. At this time, the Migrating IAB-node needs to know whether a migration between donors is in progress or whether a new F1-C connection needs to be established, but existing technology cannot indicate whether the Migrating IAB-node is performing a migration between donors or whether a new F1-C connection needs to be established. On the other hand, when the Migrating IAB-node moves between different Donors, it can maintain F1-C connections with both the original and new Donors simultaneously, requiring the simultaneous redirection of old and new F1 connections to optimize the forwarding path of the F1 connection. However, existing technology cannot enable the IAB-node to distinguish between the redirection of old and new F1-C connections.

[0013] To address at least one of the above-mentioned problems or other similar issues, embodiments of this application provide a group migration method, apparatus, and system.

[0014] According to one aspect of the embodiments of this application, a group migration apparatus is provided, configured in a second Donor device, the apparatus comprising:

[0015] When migrating an IAB node from a first Donor to a second Donor device, the processing unit performs at least one of the following processes:

[0016] The migration IAB node updates the first TNL address of the first F1-C connection to the second TNL address;

[0017] The migration IAB node updates the third TNL address of the second F1-C connection to the fourth TNL address;

[0018] Configure the migrated IAB node with a fourth TNL address for establishing the second F1-C connection;

[0019] Add a second TNL address for the first F1-C connection to the migrated IAB node;

[0020] Configure the migrating IAB node with a third TNL address for establishing the second F1-C connection;

[0021] Add a fourth TNL address for the second F1-C connection to the migrated IAB node;

[0022] Wherein, the first F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, the second F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the second Donor device, the first TNL address and the third TNL address are TNL addresses that can be routed to the DU of the first Donor device, and the second TNL address and the fourth TNL address are TNL addresses that can be routed to the DU of the second Donor device.

[0023] According to one aspect of the embodiments of this application, a group migration apparatus is provided, the apparatus being configured to migrate an IAB node, the IAB node being moved from a first Donor device to a second Donor device, wherein the apparatus includes:

[0024] The receiving unit receives a first RRC reconfiguration message sent by the second Donor device from the first Donor device, the first RRC reconfiguration message including at least one of the following:

[0025] A second TNL address is used for the first F1-C connection to update the first TNL address of the first F1-C connection to the second TNL address, or to add the second TNL address to the first F1-C connection.

[0026] The fourth TNL address is used for the second F1-C connection to update the third TNL address of the second F1-C connection to the fourth TNL address, or to establish the second F1-C connection with the CU of the second Donor device using the fourth TNL address, or to add the fourth TNL address to the second F1-C connection;

[0027] The third TNL address is used for the second F1-C connection, to add the third TNL address to the second F1-C connection, or to use the third TNL address to establish the second F1-C connection with the CU of the second Donor device;

[0028] Wherein, the first F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, the second F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the second Donor device, the first TNL address and the third TNL address are TNL addresses that can be routed to the DU of the first Donor device, and the second TNL address and the fourth TNL address are TNL addresses that can be routed to the DU of the second Donor device.

[0029] According to one aspect of the embodiments of this application, a group migration apparatus is provided, configured in a first Donor device, for migrating IAB nodes from the first Donor device to a second Donor device, wherein the apparatus includes:

[0030] The receiving unit receives the second TNL address of the first F1-C connection of the migrated IAB node sent by the second Donor device;

[0031] The processing unit updates the first TNL address of the first F1-C connection of the migrated IAB node to the second TNL address, or adds the second TNL address to the first F1-C connection of the migrated IAB node;

[0032] Wherein, the first F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, the first TNL address is the TNL address of the DU that can be routed to the first Donor device, and the second TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0033] One of the beneficial effects of this application's embodiments is that when the Migrating IAB-node moves from the original Donor to the target Donor, the target Donor can instruct the migrating IAB-node whether to perform inter-donor migration or establish a new F1-C connection. This allows the migrating IAB-node to establish a new F1-C connection with the target Donor during inter-donor migration, becoming a DU under the new Donor serving its child IAB-nodes or UEs, thus migrating the child IAB-nodes or UEs under the migrating IAB-node to the target Donor and achieving load balancing among the donor devices. On the other hand, when the Migrating IAB-node moves from the original Donor to the target Donor and maintains an F1-C connection with both the original Donor and the target Donor, the target Donor can simultaneously redirect the original F1 connection and the new F1 connection, and instruct the migrating IAB-node to redirect either the original F1-C connection or the new F1-C connection, thereby optimizing the forwarding path of the original F1-C connection and the new F1-C connection.

[0034] Specific embodiments of this application are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of this application can be adopted. It should be understood that the embodiments of this application are not limited in scope. Within the spirit and scope of the appended claims, embodiments of this application include many changes, modifications, and equivalents.

[0035] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0036] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0037] The elements and features described in one drawing or embodiment of this application may be combined with elements and features shown in one or more other drawings or embodiments. Furthermore, in the drawings, similar reference numerals denote corresponding parts in several drawings and can be used to indicate corresponding parts used in more than one embodiment.

[0038] The accompanying drawings, which form part of the specification, are used to provide a further understanding of the embodiments of this application and illustrate the implementation methods of this application, together with the textual description, to explain the principles of this application. Obviously, the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0039] Figure 1 This is a schematic diagram of the IAB system;

[0040] Figure 2 This is a schematic diagram of the IAB architecture in SA mode;

[0041] Figure 3 This is a schematic diagram of the IAB architecture in EN-DC mode;

[0042] Figure 4 This is a diagram illustrating the parent IAB-node and the child IAB-node.

[0043] Figure 5 This is a schematic diagram of the F1-U protocol stack of the IAB system;

[0044] Figure 6 This is a schematic diagram of the F1-C protocol stack of the IAB system;

[0045] Figure 7 This is a schematic diagram of an IAB node moving between different DUs under the same Donor;

[0046] Figure 8 This is a schematic diagram of a group migration method according to an embodiment of this application;

[0047] Figure 9 This is a schematic diagram of a scenario of the group migration method according to an embodiment of this application;

[0048] Figure 10 yes Figure 9 A schematic diagram of information interaction in the scenario shown.

[0049] Figure 11a and Figure 11b This is a schematic diagram of another scenario of the group migration method according to an embodiment of this application;

[0050] Figure 12 yes Figure 11a and Figure 11b The diagram illustrates the information interaction in the scenario shown.

[0051] Figure 13a and Figure 13b This is a schematic diagram of another scenario of the group migration method according to an embodiment of this application;

[0052] Figure 14 yes Figure 13a and Figure 13b The diagram illustrates the information interaction in the scenario shown.

[0053] Figure 15 This is a schematic diagram of another scenario of the group migration method according to an embodiment of this application;

[0054] Figure 16 yes Figure 15 The diagram illustrates the information interaction in the scenario shown.

[0055] Figure 17a and Figure 17b This is a schematic diagram of another scenario of the group migration method according to an embodiment of this application;

[0056] Figure 18 yes Figure 17a and Figure 17b The diagram illustrates the information interaction in the scenario shown.

[0057] Figure 19a and Figure 19b This is a schematic diagram of another scenario of the group migration method according to an embodiment of this application;

[0058] Figure 20 yes Figure 19a and Figure 19b The diagram illustrates the information interaction in the scenario shown.

[0059] Figure 21 This is a schematic diagram of a group migration device according to an embodiment of this application;

[0060] Figure 22This is another schematic diagram of the group migration device according to an embodiment of this application;

[0061] Figure 23 This is yet another schematic diagram of a group migration device according to an embodiment of this application;

[0062] Figure 24 This is another schematic diagram of the group migration device according to an embodiment of this application;

[0063] Figure 25 This is a schematic diagram of a communication system according to an embodiment of this application;

[0064] Figure 26 This is a schematic diagram of an IAB node in an embodiment of this application;

[0065] Figure 27 This is a schematic diagram of a Donor device according to an embodiment of this application. Detailed Implementation

[0066] Referring to the accompanying drawings, the foregoing and other features of this application will become apparent from the following description. Specific embodiments of this application are specifically disclosed in the description and drawings, illustrating partial implementations in which the principles of this application may be employed. It should be understood that this application is not limited to the described embodiments; rather, it includes all modifications, variations, and equivalents falling within the scope of the appended claims.

[0067] In the embodiments of this application, the terms "first," "second," etc., are used to distinguish different elements by name, but do not indicate the spatial arrangement or chronological order of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one or more of the terms listed in association and all combinations thereof. The terms "comprising," "including," "having," etc., refer to the presence of the stated features, elements, components, or assemblies, but do not exclude the presence or addition of one or more other features, elements, components, or assemblies.

[0068] In the embodiments of this application, the singular forms "a," "the," etc., including the plural forms, should be broadly understood as "a kind" or "a class" rather than limited to the meaning of "an." Furthermore, the term "the" should be understood to include both the singular and plural forms, unless the context explicitly indicates otherwise. Additionally, the term "according to" should be understood as "at least partially based on…," and the term "based on" should be understood as "at least partially based on…," unless the context explicitly indicates otherwise.

[0069] In the embodiments of this application, the term "communication network" or "wireless communication network" may refer to a network that conforms to any of the following communication standards, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), etc.

[0070] Furthermore, communication between devices in a communication system can be carried out according to communication protocols at any stage, such as including but not limited to the following communication protocols: 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G and future 5G, 6G, etc., and / or other currently known or future communication protocols.

[0071] In the embodiments of this application, the term "network device" refers, for example, to a device in a communication system that connects a terminal device to a communication network and provides services to that terminal device. Network devices may include, but are not limited to, the following devices: base station (BS), access point (AP), transmission reception point (TRP), broadcast transmitter, mobile management entity (MME), gateway, server, radio network controller (RNC), base station controller (BSC), etc.

[0072] The term "base station" can include, but is not limited to, NodeBs (or NBs), evolved NodeBs (or eNodeBs or eNBs), and 5G base stations (gNBs), etc. It can also include Remote Radio Heads (RRHs), Remote Radio Units (RRUs), relays, or low-power nodes (e.g., femto, pico, etc.). The term "base station" can encompass some or all of its functions, and each base station can provide communication coverage to a specific geographic area. The term "cell" can refer to a base station and / or its coverage area, depending on the context in which the term is used.

[0073] In the embodiments of this application, the term "user equipment" (UE) refers to a device that accesses a communication network and receives network services through a network device, and can also be called "terminal equipment" (TE). Terminal equipment can be fixed or mobile, and can also be called mobile station (MS), terminal, user, subscriber station (SS), access terminal (AT), station, etc.

[0074] The terminal device may include, but is not limited to, the following devices: cellular phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, machine-type communication device, laptop computer, cordless phone, smartphone, smartwatch, digital camera, etc.

[0075] For example, in scenarios such as the Internet of Things (IoT), terminal devices can also be machines or devices for monitoring or measurement, such as including but not limited to: machine-type communication (MTC) terminals, vehicle communication terminals, device-to-device (D2D) terminals, machine-to-machine (M2M) terminals, and so on.

[0076] Various embodiments of this application will now be described with reference to the accompanying drawings. These embodiments are merely exemplary and are not intended to limit the scope of this application.

[0077] First aspect of the embodiments

[0078] This application provides a group migration method.

[0079] Figure 8 This is a schematic diagram of a group migration method according to an embodiment of this application, described from the perspective of the second Donor device. The IAB node is migrated from the first Donor device to the second Donor device. From the perspective of the direction of movement of the migrated IAB node, the first Donor device in this embodiment is the original Donor device, hereinafter referred to as the first Donor or original Donor, and the second Donor device is the target Donor device, hereinafter referred to as the second Donor or target Donor. Figure 8 As shown, the method includes:

[0080] 801: When migrating an IAB node from a first Donor device to a second Donor device, the second Donor device performs at least one of the following processes:

[0081] The migration IAB node updates the first TNL address of the first F1-C connection to the second TNL address;

[0082] The migration IAB node updates the third TNL address of the second F1-C connection to the fourth TNL address;

[0083] Configure the migrated IAB node with a fourth TNL address for establishing the second F1-C connection;

[0084] Add a second TNL address for the first F1-C connection to the migrated IAB node;

[0085] Configure a third TNL address for establishing a second F1-C connection for the migrated IAB node; and add a fourth TNL address for the migrated IAB node for the second F1-C connection.

[0086] In this embodiment of the application, migrating an IAB node from the first Donor device to the second Donor device means that when the backhaul RLC link of the migrated IAB node under the first Donor device fails, it re-establishes a connection to the second Donor device; or, the migrated IAB node switches from the first Donor device to the second Donor device; or, the migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device.

[0087] The following sections will explain each point.

[0088] In the descriptions above and below, the first F1-C connection (referred to as the first F1-C or original F1-C) is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, and the second F1-C connection (referred to as the second F1-C or new F1-C) is the F1 connection between the DU of the migrated IAB node and the CU of the second Donor device. Furthermore, in the descriptions above and below, the first TNL address, the third TNL address, and the fifth TNL address are TNL addresses of the DUs routable to the first Donor device, and the second TNL address, the fourth TNL address, and the sixth TNL address are TNL addresses of the DUs routable to the second Donor device.

[0089] In the above embodiments, when a migrated IAB node moves from the first donor to the second donor, the second donor instructs the migrated IAB node to establish a new F1-C connection by configuring a TNL address for the second F1-C connection to the migrated IAB node. This allows the migrated IAB node to become a DU under the new donor, serving its child IAB nodes or UEs. This enables the IAB system to migrate the child IAB nodes or UEs under the migrated IAB node to the target donor, achieving load balancing between donor devices. On the other hand, when a migrated IAB node moves from the first donor to the second donor and maintains an F1-C connection with both the first and second donors, the second donor redirects the F1-C connection by updating the TNL address of either the first or second F1-C connection, optimizing the forwarding path of F1-C traffic and achieving more efficient signaling forwarding. Furthermore, the second donor increases the forwarding path of F1-C traffic by adding a TNL address to either the first or second F1-C connection, achieving more flexible signaling forwarding.

[0090] In some embodiments, when a radio link failure occurs on the backhaul RLC link under the first Donor device, the migrated IAB node re-establishes a connection to the second Donor device. The second Donor device causes the migrated IAB node to update the first TNL address of the first F1-C connection to the second TNL address, and configures a fourth TNL address for the migrated IAB node to establish the second F1-C connection.

[0091] For example, after the migrated IAB node is re-established to the second Donor device, the second Donor device sends the first RRC reconfiguration message to the migrated IAB node.

[0092] The first RRC reconfiguration message contains a second TNL address for the first F1-C connection, thereby allowing the migrating IAB node to update the first TNL address of the first F1-C connection to the second TNL address; or, the first RRC reconfiguration message contains a second TNL address for the first F1-C connection and a fourth TNL address for the second F1-C connection, thereby allowing the migrating IAB node to update the first TNL address of the first F1-C connection to the second TNL address and use the fourth TNL address to establish a second F1-C connection with the CU of the second Donor device.

[0093] Using the method described in the above embodiments, the second Donor device configures the TNL address of the first F1-C connection through RRC messages, enabling the first F1-C traffic to be forwarded through the DU of the second Donor, thus optimizing the transmission path of the first F1-C traffic. At the same time, the second Donor device configures the TNL address of the second F1-C connection through RRC messages, enabling the second F1-C connection to be established immediately after the migrated IAB node is re-established to the second Donor device, thereby enabling subsequent migration of the UE.

[0094] In the above embodiments, the first RRC reconfiguration message may further include: a BAP address assigned to the migrated IAB node; and / or, the backhaul RLC channel configuration of the migrated IAB node, and a default BAP route identifier and a default backhaul RLC channel identifier for F1-C and non-F1 data; and / or, for the migrated IAB node to update the fifth TNL address of its F1-U connection to the sixth TNL address of the sixth TNL address, so that F1-U traffic can be forwarded through the DU of the second Donor; and / or, for the BAP route identifier and backhaul RLC channel identifier of the F1-U connection of the migrated IAB node.

[0095] In the above embodiments, if the first RRC reconfiguration message does not contain the fourth TNL address used for the second F1-C connection, that is, it does not instruct the migrated IAB node to immediately establish the second F1-C connection after re-establishing with the second Donor device, the second Donor device can send a third RRC reconfiguration message to the migrated IAB node some time after sending the first RRC reconfiguration message; the third RRC reconfiguration message contains the fourth TNL address used for the second F1-C connection. Therefore, after receiving the third RRC reconfiguration message, the migrated IAB node can use the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0096] In the above embodiment, after the second Donor device establishes a second F1-C connection with the migration IAB node, in order to migrate the UE served by the migration IAB node to the second Donor device, the CU of the second Donor device can use the aforementioned fourth TNL address to send a first message to the DU of the migration IAB node through the second F1-C connection, so that the migration IAB node can establish a second context for the UE it serves based on the first message.

[0097] As an example, the first message mentioned above may include the first context identifier of the UE, so that the migration IAB node can obtain the first context of the UE based on the first context identifier and reuse the first context to establish the second context of the UE; the first message may be an F1 establishment response or a UE context modification request message.

[0098] As another example, the first message mentioned above may also include the serving cell configuration information of the UE, so as to migrate the IAB node to update the serving cell configuration of the UE.

[0099] With the method described in the above embodiments, the migration node only needs to obtain the first context of the UE based on the first context identifier and reuse the first context to establish the second context of the UE, without going through the existing UE context establishment process. This can reduce the signaling overhead and latency in UE context establishment and improve signaling efficiency.

[0100] In the above embodiments, when migrating a UE, the second Donor device can also send a second RRC reconfiguration message to the first Donor device for the UE served by the migrating IAB node, so that the first Donor device can forward the second RRC reconfiguration message to the migrating IAB node using the second TNL address through the first F1-C connection. Thus, after receiving the second RRC reconfiguration message, the migrating IAB node can send the second RRC reconfiguration message to the UE it serves.

[0101] In addition, the migration IAB node can also receive the second RRC reconfiguration completion message sent by the UE it serves, and use the fourth TNL address to send the second RRC reconfiguration completion message to the second Donor device through the second F1-C connection.

[0102] Therefore, the second Donor device can also receive the second RRC reconfiguration completion message sent by the migrated IAB node using the aforementioned fourth TNL address through the aforementioned second F1-C connection.

[0103] In the above embodiments, the first Donor device can also send a second message to the migrating IAB node via the first F1-C connection using the first TNL address. This second message contains either the sixth TNL address of the F1-U connection used for migrating the IAB node, or the sixth TNL address of the F1-U connection used for migrating the IAB node, along with the BAP routing identifier and the return RLC channel identifier of the F1-U connection used for migrating the IAB node. Thus, the migrating IAB node can receive the second message and update the fifth TNL address of its F1-U connection to the sixth TNL address, allowing F1-U traffic to be forwarded via the second Donor's DU, optimizing the transmission path of the F1-U traffic.

[0104] In the above embodiments, the first Donor device can also receive the second TNL address of the first F1-C connection of the migrated IAB node sent by the second Donor device, and update the first TNL address of the first F1-C connection of the migrated IAB node to the second TNL address, thereby redirecting the first F1-C on the first Donor device side and optimizing the transmission path of the first F1-C traffic.

[0105] In the above embodiments, the first Donor device can also receive the sixth TNL address of the F1-U connection of the migrated IAB node sent by the second Donor device, and update the fifth TNL address of the F1-U connection of the migrated IAB node to the sixth TNL address, thereby redirecting F1-U on the first Donor device side and optimizing the transmission path of F1-U traffic.

[0106] Figure 9 This is an example diagram illustrating an application scenario of the above embodiments. Figure 10 This is a schematic diagram of information interaction in the above embodiments. The following is in conjunction with... Figure 9 and Figure 10 The above embodiments will be described.

[0107] like Figure 9 As shown, a radio link failure (RLF) occurs on the migrating node's backhaul (BH) link, causing the migrating node to choose donor 2 for connection re-establishment. Since it's a re-establishment to donor 2, the migrating node can only establish an F1-C with donor 2 after connecting to donor 2. The original F1-C (old F1-C), i.e., the F1-C between donor CU 1 and the migrating node, may also be updated from the original transmission path to the new transmission path. The UE's RRC reconfiguration completion message needs to be sent to donor 2 through the new F1-C (new F1-C), i.e., the F1-C between donor CU 2 and the migrating node. Therefore, the migrating node migrates to donor 2 before the UE.

[0108] like Figure 10 As shown, the information interaction process includes:

[0109] 1001. The migrating node detects a radio link failure in the BH link and selects the cell under IAB-node 2 to re-establish the RRC connection. During this process, Donor 2 will obtain the context of the migrating node and the UE it serves from Donor 1.

[0110] 1002. After the migrating node completes the RRC re-establishment process, Donor CU 2 sends an RRCReconfiguration message to the migrating node. Because the connection has changed to donor 2, this message also contains the BAP address assigned to the migrating node by donor 2. Since the backhaul link has changed to IAB-node 2, this message also contains the BH RLC channel configuration from the migrating node to IAB-node 2, as well as the BAP route (default route) and the new BH RLC channel (default BH channel ID) for F1-C and non-F1 data.

[0111] Furthermore, since the access anchor point of the Old F1 connection established between Donor CU 1 and the migrating node changes from IAB-node 1 to IAB-node 2, the original F1 data needs to be forwarded through Donor DU 2 and IAB-node 2 under Donor 2. That is, the transmission path changes from the original path to the new path (i.e., migrating node → IAB-node 2 → Donor DU 2 → Donor CU 1). At this time, the migrating node needs to be configured with a subnet address adapted to Donor DU 2. At this time, the UE's signaling is still sent to Donor CU 1 through Old F1-C, but Old F1-C needs to be transferred to the new path. Therefore, the RRC reconfiguration message also includes the TNL address of Old F1-C to update the transmission path of Old F1-C traffic.

[0112] Furthermore, at this time, the UE's DRB data is still sent to Donor CU 1 via F1-U (i.e., the F1-U established between the migrating node and Donor CU1). The F1-U is switched from the original path to the new path (i.e., migrating node → IAB-node2 → Donor DU 2 → Donor CU 1). To minimize the interruption time of F1-U transmission, the RRC reconfiguration message can also include the TNL address of the F1-U connection, indicating the updated transmission path for F1-U traffic, so that the migrating node can immediately switch the F1-U traffic to the new path for transmission. In addition, the RRC reconfiguration message can also include the BAP route and BH RLC channel mapping relationship for the F1-U connection. For example, specifically, the RRC reconfiguration message includes the BAP route used by each UE's RLC channel, as well as the correspondence between the UE ID, the UE's RLC channel and the backhaul RLC channel of the migrating node.

[0113] There are two scenarios for establishing a New F1-C:

[0114] Scenario 1: The new F1-C is established immediately after the migrating node is re-established to Donor 2. In this case, the aforementioned RRC reconfiguration message also includes the TNL address for the new F1-C to indicate its establishment.

[0115] Scenario 2: After the migrating node is re-established to Donor 2, the UE is not immediately migrated. Therefore, the New F1-C can be established some time after the migrating node is re-established to Donor 2. In this case, the TNL address of the New F1-C will be included in the subsequent RRC reconfiguration message. See [link to RRC reconfiguration message]. Figure 10 The RRC reconfiguration process following operation 1005.

[0116] 1003, Donor CU 2 receives the RRC reconfiguration from the migrating node and initiates a core network path switch for the migrating node.

[0117] 1004. Because the data of the migrating node's New F1-C, Old F1-C, and F1-U all need to be transmitted through the new path, after Donor CU 2 receives the migrating node's RRC reconfiguration completion message, it configures the BH RLC channel, BAP layer routing, and BH RLC channel mapping relationship for the nodes on the new path.

[0118] The operation 1004 described above can be performed immediately after the operation 1001 described above, but this application does not restrict this.

[0119] 1005, migrating node uses the updated TNL address to migrate Old F1-C to the new path.

[0120] The migrating node can also use the updated TNL address to migrate the F1-U to the new path.

[0121] 1006, Migrating node uses instructions to establish a new F1-C TNL address with donor CU 2 to establish a new F1-C.

[0122] 1007. If the RRC reconfiguration message in operation 1002 does not contain F1-U configuration information, Donor CU 1 sends an F1AP message (UE context modification) to the migrating node through the Old F1-C to update the TNL address of the F1-U connection, so that F1-U traffic is converted to the new path. It can also modify the BAP route and BH RLC channel mapping relationship of the F1-U connection. For example, specifically, the F1AP message configures the BAP route used by each UE's RLC channel, and configures the correspondence between the UE ID, the UE's RLC channel and the backhaul RLC channel of the migrating node.

[0123] Operation 1007 can be executed immediately after operation 1005, but this application does not impose any restrictions on this.

[0124] 1008: To migrate the UE to donor 2, a UE context is established in the new F1-C of the migrating node. This gives the UE a separate context in both the old and new F1-C. Specifically, for the UE, the migrating node has one F1AP signaling connection with both donor CU 1 and donor CU 2. The F1AP signaling connection with donor CU 1 is used to send RRC reconfiguration messages to the UE, and the F1AP signaling connection with donor CU 2 is used to receive the UE's RRC reconfiguration completion message.

[0125] There are three methods for establishing the UE context in the migrating node's New F1-C:

[0126] Method 1: Donor CU 2 sends an F1AP message, i.e., UE context setup request, to the migrating node via New F1-C.

[0127] In Method 1, the Migrating node can assign a C-RNTI to the UE and send the C-RNTI to the Donor CU2 via the UE contextsetup response.

[0128] In Method 1, the UE contxt setup request includes the F1-U configuration for the UE's DRB. The F1-U can be configured on the donor CU1 side, with the UE's DRB using the UL TNL address of the donor CU1; or it can be configured on the donor DU2 side, with the UE's DRB using the UL TNL address of the donor CU2. Afterwards, the migrating node will switch the UE's F1-U from the donor CU1 to the donor CU2.

[0129] Method 2: Donor CU2 sends an F1AP message, i.e., UE context modification, to the migrating node via New F1-C.

[0130] In Method 2, the UE context modification carries the UE's context identifier in the Old F1-C. The migrating node can obtain the UE context under the Old F1-C based on the UE's context identifier and use it to create a new UE context in the New F1-C. Since the migrating node needs to change the serving cell identifier when switching to Donor 2, the UE context modification can include the UE's serving cell identifier. The migrating node replaces the serving cell identifier in the original UE context with this new cell identifier. Furthermore, the C-RNTI may also change when the UE changes its serving cell. Therefore, the migrating node assigns a new C-RNTI to the UE and replaces the original C-RNTI with the new one. The migrating node can send the new C-RNTI to Donor CU2 via the UE context setup response.

[0131] In Method 2, the F1-U configuration can be modified in the UE configuration modification. The modified F1-U can remain on the donor CU1 side, with the UE's DRB using the UL TNL address of Donor CU1; alternatively, the F1-U can be switched from Donor CU1 to the donor CU2 side, with the UE's DRB using the UL TNL address of Donor CU2, and then the migrating node sends the UE's DRB data to Donor CU2. This method of creating a new context using the original UE context saves signaling overhead.

[0132] Method 3: Donor CU 2 establishes a new context for the UE by sending an F1 Setup Response message when establishing a new F1-C with the migrating node.

[0133] In Method 3, the F1 Setup Response can carry multiple UE context identifiers from the old F1-C. The migrating node can obtain the UE context from the old F1-C based on the UE's context identifier and use it to create a new UE context in the new F1-C. The F1 Setup Response can also contain multiple UE serving cell identifiers, which the migrating node uses to replace the serving cell identifier in the original UE context. This allows for the creation of a new context using the UE's original context during F1 setup, eliminating the need to create a context for each UE individually, thus saving signaling overhead and latency.

[0134] 1009, migrate the UE that established the context to Donor 2, and send an RRC reconfiguration message to the UE through the original F1-C.

[0135] Since the Old F1-C is located between the migrating node and Donor CU 1, and the Old F1-C traffic is forwarded through Donor DU 2 and IAB-node 2 under Donor 2, the sending path of the RRC reconfiguration message for the UE is: Donor CU 2 → Donor CU 1 → Donor DU 2 → IAB-node 2 → migrating node.

[0136] 1010. After the handover, the UE sends an RRC reconfiguration complete message to Donor CU 2 via New F1-C. The sending path is: migrating node→IAB-node 2→Donor DU 2→Donor CU 2.

[0137] 1011. After receiving the RRC reconfiguration completion message from the UE, Donor CU 2 initiates a core network path handover for the UE.

[0138] As can be seen from the above embodiments, the second Donor device configures the TNL address of the first F1-C connection through RRC messages, enabling the first F1-C traffic to be forwarded through the DU of the second Donor device, thus optimizing the transmission path of the first F1-C traffic. Simultaneously, the second Donor device can also configure the TNL address of the second F1-C connection through RRC messages, allowing the migrated IAB node to immediately establish the second F1-C connection after re-establishing with the second Donor device, thereby migrating the UE to the second Donor device and achieving load balancing between donors. Furthermore, when establishing the UE context in the second F1-C connection, the migrating node only needs to obtain the UE's first context based on the UE's first context identifier in the first F1-C connection and reuse that first context to establish the UE's second context, without using the existing UE context establishment process. This reduces signaling overhead and latency in UE context establishment, improving signaling efficiency.

[0139] In some embodiments, the migration IAB node switches from a first Donor device to a second Donor device, and establishes a second F1-C connection after switching to the second Donor device. The second Donor device can configure a fourth TNL address for the migration IAB node to establish the second F1-C connection; or, the second Donor device can configure a fourth TNL address for the migration IAB node to establish the second F1-C connection, and cause the migration IAB node to update the first TNL address of the first F1-C connection to the second TNL address.

[0140] For example, the second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device can forward the first RRC reconfiguration message to the migrated IAB node.

[0141] The first RRC reconfiguration message includes a handover command and a fourth TNL address for the second F1-C connection, allowing the migrating IAB node to establish a second F1-C connection with the CU of the second Donor device using the fourth TNL address. Alternatively, the first RRC reconfiguration message includes a handover command and a second TNL address for the first F1-C connection, allowing the migrating IAB node to update the first TNL address of the first F1-C connection to the second TNL address.

[0142] Using the method described in the above embodiments, the second Donor device configures the TNL address of the first F1-C connection through an RRC message, indicating that the TNL address of the first F1-C connection should be updated, so that the first F1-C traffic can be forwarded through the DU of the second Donor, thus optimizing the transmission path of the first F1-C traffic. Alternatively, the second Donor device can configure the TNL address of the second F1-C connection through an RRC message, so that the second F1-C connection can be established immediately after the IAB node is migrated to the second Donor device, thereby enabling subsequent migration of the UE.

[0143] In the above embodiments, the first RRC reconfiguration message may further include: a BAP address assigned to the migrated IAB node; and / or, the backhaul RLC channel configuration for the migrated IAB node, and a default BAP route identifier and a default backhaul RLC channel identifier for F1-C and non-F1 data; and / or, for the migrated IAB node to update the fifth TNL address of its F1-U connection to the sixth TNL address of the sixth TNL address, so that F1-U traffic can be forwarded through the DU of the second Donor; and / or, for the BAP route identifier and backhaul RLC channel identifier for the migrated IAB node's F1-U connection.

[0144] In the above embodiments, if the first RRC reconfiguration message does not contain the fourth TNL address used for the second F1-C connection, that is, it does not indicate that the migrating IAB node should immediately establish the second F1-C connection after switching to the second Donor device, the second Donor device can still send a third RRC reconfiguration message to the migrating IAB node after a period of time since the migrating IAB node switched to the second Donor. This third RRC reconfiguration message contains the fourth TNL address used for the second F1-C connection. Therefore, after receiving the third RRC reconfiguration message, the migrating IAB node can use the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0145] In the above embodiment, after the second Donor device establishes a second F1-C connection with the migration IAB node, in order to migrate the UE served by the migration IAB node to the second Donor, the CU of the second Donor device can use the aforementioned fourth TNL address to send a first message to the DU of the migration IAB node through the second F1-C connection, so that the migration IAB node can establish a second context for the UE it serves; the first message can be an F1 establishment response, a UE context establishment request, or a UE context modification request message.

[0146] As an example, the first message may contain the first context identifier of the UE, so that the migration IAB node can obtain the first context of the UE based on the first context identifier and reuse the first context to establish the second context of the UE.

[0147] As another example, the first message may also contain the serving cell configuration information of the aforementioned UE, so as to migrate the IAB node to update the serving cell configuration of the aforementioned UE.

[0148] With the method described in the above embodiments, the migration node only needs to obtain the first context of the UE based on the first context identifier and reuse the first context to establish the second context of the UE. It does not need to go through the existing UE context establishment process, which can reduce the signaling overhead and latency in UE context establishment and improve signaling efficiency.

[0149] In the above embodiments, during UE migration, the second Donor device can also send a second RRC reconfiguration message for the UE served by the migrating IAB node to the first Donor device, so that the first Donor device can forward the second RRC reconfiguration message to the migrating IAB node using the second TNL address or the first TNL address via the first F1-C connection. Thus, upon receiving the second RRC reconfiguration message, the migrating IAB node can send it to the UE it serves.

[0150] In addition, the migration IAB node can also receive the second RRC reconfiguration completion message sent by the UE it serves, and use the fourth TNL address to send the second RRC reconfiguration completion message to the second Donor device through the second F1-C connection.

[0151] Therefore, the second Donor device can also receive the second RRC reconfiguration completion message sent by the migrated IAB node using the aforementioned fourth TNL address through the aforementioned second F1-C connection.

[0152] In the above embodiments, the first Donor device can also use the aforementioned second TNL address to send a second message to the migrating IAB node via the first F1-C connection. This second message includes either a sixth TNL address for the migrating IAB node's F1-U connection, or a sixth TNL address for the migrating IAB node's F1-U connection along with the BAP routing identifier and the return RLC channel identifier for the migrating IAB node's F1-U connection. Thus, the migrating IAB node can update the fifth TNL address of its F1-U connection to the sixth TNL address, allowing F1-U traffic to be forwarded via the second Donor's DU, optimizing the transmission path of the F1-U traffic.

[0153] In the above embodiments, the first Donor device can also receive the second TNL address of the first F1-C connection of the migrated IAB node sent by the second Donor device, and update the first TNL address of the first F1-C connection of the migrated IAB node to the second TNL address, thereby redirecting the first F1-C on the first Donor device side and optimizing the transmission path of the first F1-C traffic.

[0154] In the above embodiments, the first Donor device can also receive the sixth TNL address of the F1-U connection of the migrated IAB node sent by the second Donor device, and update the fifth TNL address of the F1-U connection of the migrated IAB node to the sixth TNL address, thereby redirecting F1-U on the first Donor device side and optimizing the transmission path of F1-U traffic.

[0155] In the above embodiments, if an RRC reconfiguration message for a UE serving a migrated IAB node is sent before the handover, the first Donor device may receive a second RRC reconfiguration message for a UE serving a migrated IAB node sent by the second Donor device before updating the first TNL address of the first F1-C connection of the migrated IAB node to the second TNL address. The second RRC reconfiguration message is then sent to the migrated IAB node via the first F1-C connection using the first TNL address, so that the migrated IAB node forwards the second RRC reconfiguration message to the UE it serves.

[0156] Figure 11a and Figure 11b This is an example diagram illustrating an application scenario of the above embodiments. Figure 12 This is a schematic diagram of information interaction in the above embodiments. The following is in conjunction with... Figure 11a and Figure 11b and Figure 12 The above embodiments will be described.

[0157] like Figure 11a and Figure 11b As shown, the migrating node switches from Donor 1 to Donor 2. Since it's switching to Donor 2, an F1-C connection needs to be established with Donor 2. Figure 11a and Figure 11b and Figure 12In the example, the New F1-C uses a new transmission path from the migrating node to Donor 2. The Old F1-C may be updated from the original transmission path to the new transmission path. Since the New F1-C is established through the new transmission path, the migrating node must first connect to Donor 1 and then establish the New F1-C with Donor 2. The UE's handover completion (reconfiguration completion) message needs to be sent to Donor 2 through the new F1-C; therefore, the migrating node migrates to Donor 2 before the UE.

[0158] like Figure 12 As shown, the information interaction process includes:

[0159] 1201. The migrating node sends a measurement report to Donor CU 1. Based on the measurement report, Donor CU 1 determines to initiate a handover request to Donor CU 2. Donor CU 1 sends the migrating node and the context of the UE it serves to Donor CU 2. Donor CU 2 establishes a context for the migrating node in IAB-node 2, and then sends a handover request response to Donor CU 1. This handover request response carries an RRCReconfiguration message.

[0160] 1202. After receiving the handover request response, Donor CU 1 sends an RRCReconfiguration message for the migrating node, carried in the handover request response, to the migrating node. Because the connection has changed to Donor 2, this message contains the BAP address assigned to the migrating node by Donor 2. Since the backhaul link has changed to IAB-node 2, it also contains the BH RLC channel configuration from the migrating node to IAB-node 2, as well as the BAP route (default route) and BH RLC channel (default BH channel) for F1-C and non-F1 data.

[0161] Furthermore, because the access anchor point of the Old F1 connection established between Donor CU 1 and the migrating node changes from IAB-node 1 to IAB-node 2, the original F1 data can be forwarded through Donor DU 2 and IAB-node 2 under Donor 2. That is, the transmission is changed from the original path to the new path (i.e., migrating node→IAB-node 2→Donor DU→Donor CU1). It is necessary to configure the migrating node with a subnet address adapted to Donor DU 2. Therefore, Donor CU 2 updates the TNL address of F1 for the migrating node.

[0162] and Figure 9 and Figure 10 The difference from the previous implementation is that, since the inter-donor migration process is based on handover preparation, the RRC reconfiguration message to the UE may have already been sent to the migrating node through the original F1-C. Therefore, the original F1-C may not need to be transferred to the new path, so including the TNL address of the Old F1-C in the RRC reconfiguration message is optional.

[0163] Furthermore, at this time, the UE's DRB data is still sent to Donor CU1 via F1-U (i.e., the F1-U established between the migrating node and Donor CU1). The F1-U is then switched from the original path to a new path (i.e., migrating node → IAB-node2 → Donor DU 2 → Donor CU 1). To minimize the interruption time of F1-U transmission, this message can also include the TNL address of the F1-U connection, indicating the updated transmission path for F1-U traffic, allowing the migrating node to immediately switch the F1-U traffic to the new path. In addition, this RRC reconfiguration message can be used to update the BAP routes and BH RLC channel mappings used for F1-U connections. Specifically, this RRC reconfiguration message configures the BAP routes used by each UE's RLC channels, and configures the mapping between the UE ID, the UE's RLC channels, and the backhaul RLC channels of the migrating node.

[0164] exist Figure 12 In the example, there are two cases for creating New F1-C:

[0165] Scenario 1: The new F1-C is established immediately after the migrating node switches to Donor 2. In this case, the aforementioned RRC reconfiguration message also includes the TNL address for the new F1-C to indicate its establishment.

[0166] Scenario 2: After the migrating node switches to Donor 2, the UE is not migrated immediately. Therefore, the New F1-C can be established some time after the migrating node has completed its migration. In this case, the TNL address of the New F1-C will be included in the subsequent RRC reconfiguration message. See [link to RRC reconfiguration message]. Figure 12 The RRC reconfiguration process following operation 1205.

[0167] Implementation of 1203-1211 and Figure 10 The same applies to 1003 to 1011, so explanation is omitted here. It should be noted that oldF1-C redirection is optional, and... Figure 12 In the example, 1210 (that is, sending an RRC reconfiguration message to the UE via old F1-C) can be executed immediately after 1201.

[0168] As can be seen from the above embodiments, the second Donor device can configure the TNL address of the first F1-C connection through RRC messages, indicating the update of the TNL address of the first F1-C connection, so that the first F1-C traffic can be forwarded through the DU of the second Donor device, thus optimizing the transmission path of the first F1-C traffic. Alternatively, the second Donor device can configure the TNL address of the second F1-C connection through RRC messages, so that the second F1-C connection is established immediately after the migrated IAB node switches to the second Donor device, thereby migrating the UE to the second Donor device and achieving load balancing between donors. In addition, when establishing the UE context in the second F1-C connection, the migrating node only needs to obtain the first context of the UE based on the first context identifier of the UE in the first F1-C connection and reuse the first context to establish the second context of the UE, without using the existing UE context establishment message, which can reduce the signaling overhead and latency in UE context establishment and improve signaling efficiency.

[0169] In some embodiments, the migration IAB node switches from a first Donor device to a second Donor device, establishing a second F1-C connection before switching. The second Donor device causes the migration IAB node to update the third TNL address used for the second F1-C connection to a fourth TNL address.

[0170] For example, the second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node. This first RRC reconfiguration message contains a handover command and a fourth TNL address for the second F1-C connection. Thus, the migrated IAB node can update the third TNL address of the second F1-C connection to the fourth TNL address.

[0171] Using the method described in the above embodiments, the second Donor device configures the TNL address of the second F1-C connection through RRC messages, indicating that the TNL address of the second F1-C connection should be updated, so that the second F1-C traffic can be forwarded through the DU of the second Donor, thus optimizing the transmission path of the second F1-C traffic.

[0172] In the above embodiments, the first RRC reconfiguration message may further include: a BAP address assigned to the migrated IAB node; and / or, the backhaul RLC channel configuration for the migrated IAB node, and a default BAP route identifier and a default backhaul RLC channel identifier for F1-C and non-F1 data; and / or, for the migrated IAB node to update the fifth TNL address of its F1-U connection to the sixth TNL address of the sixth TNL address, so that F1-U traffic can be forwarded through the DU of the second Donor; and / or, for the BAP route identifier and backhaul RLC channel identifier for the migrated IAB node's F1-U connection.

[0173] In the above embodiment, before the second Donor device sends the first RRC reconfiguration message for the migrated IAB node to the first Donor device, the CU of the second Donor device can use the third TNL address to send the first message to the DU of the migrated IAB node through the second F1-C connection, so that the migrated IAB node can establish a second context for the UE it serves based on the first message.

[0174] As an example, the first message may contain the first context identifier of the UE, so that the migration IAB node can obtain the first context of the UE based on the first context identifier and reuse the first context to establish the second context of the UE. The first message may be an F1 establishment response or a UE context modification request message.

[0175] As another example, the first message may also contain the serving cell configuration information of the aforementioned UE, so as to migrate the IAB node to update the serving cell configuration of the aforementioned UE.

[0176] Using the method described in the above embodiments, the migration node only needs to obtain the first context of the UE based on the first context identifier and reuse the first context to establish the second context of the UE, without needing to use the existing UE context establishment message. This can reduce the signaling overhead and latency in UE context establishment and improve signaling efficiency.

[0177] In the above embodiment, before the migrating IAB node receives the first RRC reconfiguration message, the first Donor device also sends a third RRC reconfiguration message to the migrating IAB node. This third RRC reconfiguration message contains a third TNL address for the second F1-C connection. Therefore, after receiving the third RRC reconfiguration message, the migrating IAB node can use the third TNL address to establish a second F1-C connection with the CU of the second Donor device, thereby enabling the migration of the UE.

[0178] In the above embodiments, during UE migration, the second Donor device can also send a second RRC reconfiguration message for the UE served by the migrating IAB node to the first Donor device, so that the first Donor device can forward the second RRC reconfiguration message to the migrating IAB node using the first TNL address via the first F1-C connection. Thus, upon receiving the second RRC reconfiguration message, the migrating IAB node can send it to the UE it serves.

[0179] In addition, the migration IAB node can also receive the second RRC reconfiguration completion message sent by the UE it serves, and send the second RRC reconfiguration completion message to the second Donor device via the second F1-C connection using the third TNL address or the fourth TNL address.

[0180] Therefore, if an RRC reconfiguration completion message for a UE serving the migrated IAB node is sent before the migration node handover, the second Donor device can also receive a second RRC reconfiguration completion message sent by the migrated IAB node using the aforementioned third TNL address through the aforementioned second F1-C connection; or, if an RRC reconfiguration completion message for a UE serving the migrated IAB node is sent after the migration node handover, the second Donor device receives a second RRC reconfiguration completion message sent by the migrated IAB node using the fourth TNL address through the second F1-C connection.

[0181] In the above embodiment, since the first Donor device allocates the third TNL address, it can also send the third TNL address to the second Donor device for establishing a second F1-C connection with the migrated IAB node. Thus, the second Donor device can establish a second F1-C connection with the migrated IAB node.

[0182] In the above embodiments, the first Donor device can also receive the sixth TNL address of the F1-U connection of the migrated IAB node sent by the second Donor device, update the fifth TNL address of the F1-U connection of the migrated IAB node to the sixth TNL address, thereby redirecting F1-U on the first Donor device side and optimizing the transmission path of F1-U traffic.

[0183] Figure 13a and Figure 13b This is an example diagram illustrating an application scenario of the above embodiments. Figure 14 This is a schematic diagram of information interaction in the above embodiments. The following is in conjunction with... Figure 13a and Figure 13b and Figure 14 The above embodiments will be described.

[0184] like Figure 13a and Figure 13b As shown, the migrating node has switched from Donor 1 to Donor 2. Figure 11a and Figure 11b and Figure 12 The example is the same; since it's a switch to Donor 2, it ultimately requires establishing F1-C with Donor 2. Figure 11a and Figure 11b and Figure 12 The example is different, in Figure 13a and Figure 13b and Figure 14 In the example, the New F1-C is established via the original transmission path, and then the new transmission path is updated. The Old F1-C may also be updated from the original transmission path to the new transmission path. Since the New F1-C is established via the original transmission path, the migrating node must establish the New F1-C before accessing Donor 2. In this case, the UE can migrate to donor 2 before the migrating node.

[0185] like Figure 14 As shown, the information interaction process includes:

[0186] 1401, the migrating node sends a measurement report to Donor CU 1. Based on the measurement report, Donor CU 1 determines to initiate a handover request to Donor CU 2. Donor CU 1 sends the migrating node and the context of the UE it serves to Donor CU 2. Donor CU 2 establishes a context for the migrating node in IAB-node 2, and then sends a handover request response to Donor CU 1, which carries an RRCReconfiguration message.

[0187] At 1402, after receiving the handover request response, Donor CU 1 sends an RRC Reconfiguration message to the migrating node to establish a new F1-C. The RRC reconfiguration message contains the TNL address for the new F1-C to indicate its establishment. The migrating node then sends an RRC reconfiguration complete message to Donor CU 1.

[0188] 1403, because a New F1-C is established with Donor CU 2 through the original path (i.e., migrating node→IAB-node 1→Donor DU 1→Donor CU 2), after Donor CU 1 receives the RRC reconfiguration from the migrating node, it configures the BH RLC channel, BAP layer routing, and BH RLC channel mapping relationship for the nodes on the original path.

[0189] Operation 1403 can be executed immediately after operation 1401, but this application is not limited to this.

[0190] 1404, Migrating node uses instructions to establish the TNL address of New F1-C with donor CU 2 to establish New F1-C.

[0191] 1405. To migrate the UE to donor 2, a UE context is established in the new F1-C of the migrating node. This gives the UE a separate context in both the old and new F1-C. Specifically, for the UE, the migrating node has one F1AP signaling connection with both donor CU 1 and donor CU 2. The F1AP signaling connection with donor CU 1 is used to send RRC reconfiguration messages to the UE, and the F1AP signaling connection with donor CU 2 is used to receive the UE's RRC reconfiguration completion message.

[0192] There are three methods for establishing the UE context in the migrating node's New F1-C:

[0193] Method 1: Donor CU 2 sends an F1AP message, i.e., UE context setup request, to the migrating node via New F1-C.

[0194] In Method 1, the Migrating node can assign a C-RNTI to the UE and send the C-RNTI to the Donor CU 2 via the UE contextsetup response.

[0195] In Method 1, the UE contxt setup request includes the F1-U configuration for the UE's DRB. The F1-U can be configured on the donor CU1 side, in which case the UE's DRB uses the UL TNL address of the donor CU1; or it can be configured on the donor CU2 side, in which case the UE's DRB uses the UL TNL address of the donor CU2. Afterwards, the migrating node will switch the UE's F1-U from the donor CU1 to the donor CU2.

[0196] Method 2: Donor CU2 sends an F1AP message, i.e., UE context modification, to the migrating node via New F1-C.

[0197] In Method 2, the UE context modification carries the UE's context identifier in the Old F1-C. The migrating node can obtain the UE context under the Old F1-C based on the UE's context identifier and use it to create a new UE context in the New F1-C.

[0198] In Method 2, since the migrating node needs to change the serving cell identifier when switching to donor 2, the UE context modification message can configure the UE's serving cell identifier, and the migrating node replaces the original serving cell identifier in the UE context with this serving cell identifier.

[0199] In Method 2, the C-RNTI may change when the UE migrates to a new serving cell. Therefore, the migrating node assigns a new C-RNTI to the UE, replacing the original C-RNTI. The migrating node sends the new C-RNTI to the Donor CU2 via the UE contextsetup response. This method of creating a new context using the original UE context saves signaling overhead.

[0200] In Method 2, the F1-U configuration can be modified in the UE configuration modification. The modified F1-U can remain on the donor CU1 side, in which case the UE's DRB uses the UL TNL address of the donor CU1; or the F1-U can be switched from the donor CU1 side to the donor CU2 side, in which case the UE's DRB uses the UL TNL address of the donor CU2, and then the migrating node sends the UE's DRB data to the donor CU2.

[0201] If, in 1405, the UE's F1-U switches from Donor CU 1 to Donor CU 2, then the F1-U traffic needs to be transmitted to Donor CU 2 through the original path (i.e., the transmission path is: migrating node→IAB-node 1→Donor DU 1→Donor CU 2).

[0202] Method 3: Donor CU 2 establishes a new UE context by sending an F1 Setup Response message when establishing a new F1-C with the migrating node.

[0203] In Method 3, the F1 Setup Response can carry the context identifiers of multiple UEs in the old F1-C. The migrating node can obtain the UE context under the old F1-C based on the UE's context identifier and use it to create a new UE context in the new F1-C. The F1 Setup Response can also contain the serving cell identifiers of multiple UEs, and the migrating node replaces the serving cell identifier in the original UE context with this cell identifier. In this way, a new context is created using the original UE context during F1 setup, eliminating the process of creating each UE context separately, which can save signaling overhead and signaling latency.

[0204] At 1406, the UE that established the context was migrated to Donor 2, and Donor CU 1 sent an RRC reconfiguration message to the UE through Old F1-C.

[0205] Operation 1406 can also be executed immediately after operation 1401, but this application is not limited to this. The sending path of the UE's RRC reconfiguration message is Donor CU 1 → Donor DU 1 → IAB-node 1 → migrating node.

[0206] In operation 1406, the UE can send an RRC reconfiguration complete message to Donor CU 2 via New F1-C. Since New F1-C is between migrating node and Donor CU 2, the New F1-C traffic is forwarded through Donor DU1 and IAB-node 1 under Donor 1. That is, the transmission path is: migrating node → IAB-node 1 → Donor DU 1 → DonorCU 2.

[0207] At 1407, after Donor CU 2 receives the RRC reconfiguration completion message from the UE, it initiates a core network path handover for the UE.

[0208] 1408, Donor CU 1 sends a handover request response to the migrating node, carrying an RRCReconfiguration message for the migrating node, to switch the migrating node to Donor 2, which includes the target cell and key update information under IAB-node 2.

[0209] Because the connection has changed to donor 2, the message also contains the BAP address assigned by donor 2 to migratingnode. Since the backhaul link has changed to IAB-node 2, the message also contains the BH RLC channel configuration from migratingnode to IAB-node 2, as well as the BAP route (default route) and the new BH RLC channel (default BH RLC channel) for F1-C and non-F1 data.

[0210] Because the access anchor point of the migrating node's F1 connection changes from IAB-node 1 to IAB-node 2, the original F1 data needs to be forwarded through Donor DU 2 and IAB-node 2 under Donor 2. That is, the transmission changes from the original path to the new path (i.e., migrating node → IAB-node 2 → Donor DU 2). Therefore, the migrating node needs to be configured with a subnet address adapted to Donor DU 2. Thus, Donor CU 2 needs to update the TNL address of the migrating node's F1 connection. The new F1-C needs to switch to the new path, updating its TNL address. Furthermore, since the UE has already completed the handover, the old F1-C does not need to switch to the new path.

[0211] In this process, F1-U traffic is also switched from the original path to the new path (i.e., migrating node → IAB-node 2 → Donor DU2 → Donor CU1 or Donor CU2). To minimize the interruption time of F1-U transmission, the message can also include the TNL address of the F1-U connection, allowing the migrating node to immediately switch F1-U traffic to the new path. In addition, the BAP routes and BH RLC channel mappings for F1-U connections can be reconfigured. Specifically, the message configures the BAP routes used for each UE's RLC channels, and configures the mapping between the UE ID, the UE's RLC channels, and the return RLC channels of the migrating node.

[0212] At 1409, after Donor CU 2 receives the RRC reconfiguration completion message from the migrating node, it initiates a core network path switch for the migrating node.

[0213] 1410. Because the data of the migrating node's New F1-C, Old F1-C, and F1-U all need to be transmitted through the new path, after Donor CU 2 receives the migrating node's RRC reconfiguration completion message, it configures the BH RLC channel, BAP layer routing, and BH RLC channel mapping relationship for the nodes on the new path.

[0214] Operation 1410 can be executed immediately after operation 1401, but this application is not limited to this.

[0215] 1411, New F1-C uses the updated TNL address to be converted to the new path. Additionally, F1-U can also be converted to the new path using the updated TNL address.

[0216] As can be seen from the above embodiments, before the IAB node migration handover, the second Donor device configures the TNL address of the second F1-C connection via RRC messages, enabling the migrating IAB node to establish the second F1-C connection, thereby migrating the UE to the second Donor device and achieving load balancing between donors. Simultaneously, during the IAB node migration handover, the second Donor device configures the TNL address of the second F1-C connection via RRC messages to indicate the update of the second F1-C connection TNL address, allowing second F1-C traffic to be forwarded through the second Donor's DU, thus optimizing the transmission path of second F1-C traffic. Furthermore, when establishing the UE context in the second F1-C connection, the migrating node only needs to obtain the UE's first context based on the UE's first context identifier in the first F1-C connection and reuse that first context to establish the UE's second context, without using existing UE context establishment messages. This reduces signaling overhead and latency in UE context establishment, improving signaling efficiency.

[0217] In some embodiments, the migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device. The migrated node does not need to operate as a DU under the second Donor device; that is, the UE served by the migrated IAB node does not need to migrate to the second Donor device, and the migrated IAB node does not need to establish a second F1-C. The second Donor device adds a second TNL address for the migrated IAB node to facilitate the first F1-C connection.

[0218] For example, the second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node. This first RRC reconfiguration message contains secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection. Thus, the migrated IAB node can add a second TNL address for the first F1-C connection.

[0219] According to the method of the above embodiment, the second Donor device configures the TNL address of the first F1-C connection through RRC messages to indicate the addition of the TNL address of the first F1-C connection, so that the first F1-C traffic can be forwarded through the DU of the first Donor and the second Donor at the same time, thereby improving the flexibility of the first F1-C traffic forwarding.

[0220] In the above embodiments, the first RRC reconfiguration message may further include: a BAP address assigned to the migrated IAB node; and / or, backhaul RLC channel configuration for the secondary cell group of the migrated IAB node; and / or, a BAP route identifier and a backhaul RLC channel identifier for the second F1-C connection; and / or, a sixth TNL address added to the F1-U connection of the migrated IAB node, so that F1-U traffic can be forwarded through the DU of the first Donor and the second Donor simultaneously; and / or, a BAP route identifier and a backhaul RLC channel identifier for the F1-U connection of the migrated IAB node.

[0221] In the above embodiment, the first Donor device can receive the second TNL address of the first F1-C connection of the migrated IAB node sent by the second Donor device, and add the second TNL address to the first F1-C connection of the migrated IAB node, thereby redirecting the first F1-C on the first Donor device side and increasing the transmission path of the first F1-C traffic.

[0222] In the above embodiments, the first Donor device can also receive the sixth TNL address of the F1-U connection of the migrated IAB node sent by the second Donor device, and add the sixth TNL address to the F1-U connection of the migrated IAB node. For example, the first Donor device can use the first TNL address or the second TNL address to send a second message to the migrated IAB node through the first F1-C connection. The second message may include the sixth TNL address for the F1-U connection; and / or, the BAP route identifier and the return RLC channel identifier for the F1-U connection. Thus, the migrated IAB node can update the fifth TNL address of its F1-U connection to the sixth TNL address, so that F1-U traffic can be forwarded through the DU of both the first and second Donors simultaneously, optimizing the transmission path of F1-U traffic.

[0223] Figure 15 This is an example diagram illustrating an application scenario of the above embodiments. Figure 16 This is a schematic diagram of information interaction in the above embodiments. The following is in conjunction with... Figure 15 and Figure 16 The above embodiments will be described.

[0224] like Figure 15 As shown, when the migrating node moves from Donor 1 to Donor 2, a new transmission path is added, maintaining a dual-connection with both Donor 1 and Donor 2. Specifically, an SCG connection is established with Donor 2, and the connection with Donor 1 becomes an MCG connection. Figure 15 and Figure 16 In the example, the migrated IAB node does not establish an F1-C with Donor 2, and F1-C 2 adds a new transmission path (or updates to the new transmission path). Some UEs' F1AP messages are transmitted through the original path, while some UEs' F1AP messages are updated to the new path.

[0225] like Figure 16 As shown, the information interaction process includes:

[0226] 1601. The migrating node sends a measurement report to Donor CU 1. Based on the measurement report, Donor CU 1 determines to initiate a request to add a secondary node to Donor CU 2. Donor CU 1 sends the migrating node and the context of the UE it serves to Donor CU 2. Donor CU 2 establishes the context for the migrating node in IAB-node 2, and then sends an add secondary node request response to Donor CU 1, which carries an RRCReconfiguration message.

[0227] 1602, after Donor CU 1 receives the response to the request to add a secondary node, it sends the RRCReconfiguration message for the migrating node carried in the response to the migrating node.

[0228] Because of the added SCG connection to Donor 2, this message contains the BAP address assigned by Donor 2 to the migrating node. F1-C traffic is transmitted via the new path in two ways:

[0229] Method 1: Transmit F1-C traffic via SRB signaling radio bearer;

[0230] Method 2: Transmit F1-C traffic via the BH RLC channel.

[0231] In Method 1, no additional backhaul link configuration is required. In Method 2, a backhaul link from the migrating node to IAB-node 2 needs to be added. Therefore, the message also includes the BH RLC channel configuration from the migrating node to IAB-node 2, as well as the need to add a new transmission path (i.e., migrating node→IAB-node 2→Donor DU→DonorCU1). Thus, the message also adds (or updates) the BAP routing and BH RLC channel configuration for F1-C and non-F1 data.

[0232] Furthermore, because IAB-node 2 needs to be added as the access anchor point for F1 connections (or the access anchor point needs to be switched to IAB-node 2), F1 data is forwarded through Donor DU 2 and IAB-node 2 under Donor 2. Therefore, the migrating node needs to be configured with a subnet address adapted to Donor DU 2. Thus, Donor CU 2 needs to add an F1-C TNL address to the migrating node to increase the transmission path for F1-C traffic. Specifically, the UE's F1AP signaling is sent to Donor CU 1 through the Old F1-C. After adding a transmission path for F1-C, some UE signaling will be sent through the original path, while some UE signaling can be sent through the new path.

[0233] In addition, the F1-U traffic of some or all UEs is also switched from the original path to the new path (migrating node → IAB-node 2 → Donor DU 2 → Donor CU 1 or Donor CU2). To reduce signaling transmission latency and minimize F1-U transmission interruption time, the RRC message may also include the TNL address of the F1-U connection, allowing the migrating node to immediately switch F1-U traffic to the new path. Furthermore, the BAP route and BH RLC channel mapping for the F1-U connection can be configured. For example, specifically, the message configures the BAP route used by each UE's RLC channel, and configures the mapping between the UE ID, the UE's RLC channel, and the return RLC channel of the migrating node.

[0234] At 1603, the Migrating node sends an RRC reconfiguration complete message to Donor CU 1, and Donor CU 1 sends a Secondary node reconfiguration complete message to Donor CU 2.

[0235] At 1604, after receiving the secondary node reconfiguration completion message and the migrating node random access message, Donor CU 2 initiates a core network path update for the migrating node.

[0236] 1605, because the data of the migrating node's F1-C and F1-U need to be transmitted through the new path, DonorCU 2 receives the Secondary node reconfiguration completion message and the migrating node's random access process, and then updates the BH RLC channel configuration, BAP layer routing, and BH RLC channel mapping relationship configuration for the nodes on the new path.

[0237] Operation 1605 can be executed immediately after operation 1601, but this application is not limited to this.

[0238] 1606 adds a TNL address to the F1-C connection, transferring some or all UE signaling of the F1-C to the new path.

[0239] For example, F1-C traffic can be transmitted via the signaling radio bearer SRB from the migrating node to IAB-node 2; or via the BH RLC channel from the migrating node to IAB-node 2.

[0240] 1607. If 1602 contains the TNL configuration for the F1-U connection, then add a TNL address for the F1-U connection and transfer the DRB of some UEs connected to the F1-U connection to the new path.

[0241] According to the method of the above embodiment, the second Donor device configures the TNL address of the first F1-C connection through RRC messages to indicate the addition of the first F1-C connection TNL address, so that the first F1-C traffic can be forwarded through the DU of the first Donor and the second Donor at the same time, thereby improving the flexibility of the first F1-C traffic forwarding.

[0242] In some embodiments, the migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device. After adding the air interface connection with the second Donor device, the migrated IAB node establishes a second F1-C. The second Donor device configures a fourth TNL address or a third TNL address for the migrated IAB node to establish the second F1-C connection, or the second Donor device adds a second TNL address for the migrated IAB node to establish the first F1-C connection.

[0243] For example, the second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device can forward the first RRC reconfiguration message to the migrated IAB node.

[0244] The first RRC reconfiguration message contains secondary cell group (SCG) configuration information and a fourth TNL address or a third TNL address for the second F1-C connection. Thus, the migrating IAB node can use the fourth TNL address or the third TNL address to establish a second F1-C connection with the CU of the second Donor device. Alternatively, the first RRC reconfiguration message contains secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection. Thus, the migrating IAB node can add a second TNL address to the first F1-C.

[0245] According to the method of the above embodiments, the second Donor device configures the TNL address of the first F1-C connection through RRC messages, indicating the update of the TNL address of the first F1-C connection, so that the first F1-C traffic can be forwarded through the DU of the second Donor, thus optimizing the transmission path of the first F1-C traffic. Alternatively, the second Donor device can configure the TNL address of the second F1-C connection through RRC messages, so that the second F1-C connection can be established immediately after the migration IAB node adds an air interface connection with the second Donor device, thereby realizing the migration of the UE.

[0246] In the above embodiments, the first RRC reconfiguration message may further include: a BAP address assigned to the migrated IAB node; and / or, backhaul RLC channel configuration for the secondary cell group of the migrated IAB node; a BAP route identifier and a backhaul RLC channel identifier for the second F1-C connection; a sixth TNL address added for the F1-U connection of the migrated IAB node, so that F1-U traffic can be forwarded through the DU of both the first Donor and the second Donor simultaneously; and a BAP route identifier and a backhaul RLC channel identifier for the F1-U connection of the migrated IAB node.

[0247] In the above embodiments, if the first RRC reconfiguration message does not contain the fourth TNL address used for the second F1-C connection, that is, it does not instruct the migrating IAB node to establish a second F1-C connection when adding an air interface connection with the second Donor device, after the migrating IAB node adds an air interface connection with the second Donor device, the second Donor device can still send a third RRC reconfiguration message to the migrating IAB node. This third RRC reconfiguration message contains the fourth TNL address used for the second F1-C connection. Therefore, after receiving the third RRC reconfiguration message, the migrating IAB node can use the fourth TNL address to establish a second F1-C connection with the CU of the second Donor device.

[0248] In the above embodiment, after the second Donor device establishes a second F1-C connection with the migration IAB node, in order to migrate the UE served by the migration IAB node to the second Donor, the CU of the second Donor device can use the third TNL address or the fourth TNL address to send a first message to the migration IAB node through the second F1-C connection, so that the migration IAB node can establish a second context for the UE it serves based on the first message.

[0249] As an example, the first message mentioned above contains the first context identifier of the UE, so that the migration IAB node can obtain the first context of the UE based on the first context identifier and reuse the first context to establish the second context of the UE; the first message can be an F1 establishment response or a UE context modification request message.

[0250] As another example, the first message also includes the serving cell configuration information of the UE, so that the IAB node can be migrated to update the serving cell configuration of the UE.

[0251] With the method described in the above embodiments, the migration node only needs to obtain the first context of the UE based on the first context identifier and reuse the first context to establish the second context of the UE. It does not need to go through the existing UE context establishment process, which can reduce the signaling overhead and latency in UE context establishment and improve signaling efficiency.

[0252] In the above embodiments, during UE migration, the second Donor device can also send a second RRC reconfiguration message for the UE served by the migrating IAB node to the first Donor device, so that the first Donor device can forward the second RRC reconfiguration message to the migrating IAB node using the first TNL address or the second TNL address via the first F1-C connection. Thus, upon receiving the second RRC reconfiguration message, the migrating IAB node can send it to the UE it serves.

[0253] In addition, the migration IAB node can also receive the second RRC reconfiguration completion message sent by the UE it serves, and send the second RRC reconfiguration completion message to the second Donor device via the second F1-C connection using the third TNL address or the fourth TNL address.

[0254] Therefore, the second Donor device can also receive the second RRC reconfiguration completion message sent by the migrated IAB node using the aforementioned third TNL address through the second F1-C connection; or, receive the second RRC reconfiguration completion message sent by the migrated IAB node using the aforementioned fourth TNL address through the second F1-C connection.

[0255] In the above embodiment, as an example, because the first Donor device allocates the third TNL address, the first Donor device can also send the third TNL address for migrating the IAB node to the second Donor device. Thus, the second Donor device can establish a second F1-C connection with the migrating IAB node.

[0256] In the above embodiments, as another example, the first Donor device can send a third TNL address for migrating the second F1-C connection of the IAB node to the second Donor device, and receive the second TNL address for migrating the first F1-C connection of the IAB node sent by the second Donor device, and add the second TNL address to the first F1-C connection for migrating the IAB node. Thus, the second Donor device can establish a second F1-C connection with the migrating IAB node, and add a transmission path for the first F1-C traffic on the first Donor device side, making the transmission of the first F1-C traffic more flexible.

[0257] In the above embodiments, the first Donor device can also receive the sixth TNL address of the F1-U connection of the migrated IAB node sent by the second Donor device, and add the sixth TNL address to the F1-U connection of the migrated IAB node. For example, the first Donor device can use the first TNL address or the second TNL address to send a second message to the migrated IAB node through the first F1-C connection. The second message may include the sixth TNL address for the F1-U connection; and / or, the BAP route identifier and the return RLC channel identifier for the F1-U connection. Thus, the migrated IAB node can update the fifth TNL address of its F1-U connection to the sixth TNL address, thereby increasing the transmission path of F1-U traffic on the first Donor device side and making the transmission of F1-U traffic more flexible.

[0258] In the above embodiments, if the second Donor does not instruct the establishment of a second F1-C connection when the migrating IAB node adds an air interface connection with the second Donor, the first Donor device can still send a third RRC reconfiguration message to the migrating IAB node after a period of time since the migrating IAB node added the air interface connection with the second Donor. This third RRC reconfiguration message contains the aforementioned third TNL address. After receiving the third RRC reconfiguration message, the migrating IAB node can establish a second F1-C connection with the CU of the second Donor device.

[0259] Figure 17a and Figure 17b This is an example diagram illustrating an application scenario of the above embodiments. Figure 18 This is a schematic diagram of information interaction in the above embodiments. The following is in conjunction with... Figure 17a and Figure 17b and Figure 18 The above embodiments will be described.

[0260] like Figure 17a and Figure 17b As shown, when the migrating node moves from Donor 1 to Donor 2, a new transmission path is added, maintaining a dual-connection with both Donor 1 and Donor 2. Specifically, an SCG connection is established with Donor 2, and the connection with Donor 1 becomes an MCG connection. Figure 17a and Figure 17b and Figure 18 In the example, the migrating node establishes a New F1-C with Donor 2 via either a new transmission path or the original path. An additional transmission path can be added to the Old F1-C. The migrating node first establishes an SCG connection with Donor 2, and then establishes the New F1-C. Because the UE's handover completion message needs to be sent to Donor 2 via the New F1-C, the UE can only migrate to Donor 2 after the migrating node has established an SCG connection with Donor 2.

[0261] like Figure 18 As shown, the information interaction process includes:

[0262] At 1801, the migrating node sends a measurement report to Donor CU 1. Based on the measurement report, Donor CU 1 determines to initiate a request to add a secondary node to Donor CU 2. Donor CU 1 sends the migrating node and the context of the UE it serves to Donor CU 2. Donor CU 2 establishes the context for the migrating node in IAB-node 2, and then sends an add secondary node request response to Donor CU 1, which carries an RRCReconfiguration message.

[0263] At 1802, after receiving the response to the request to add a secondary node, Donor CU 1 sends an RRCReconfiguration message for the migrating node, which is carried in the response.

[0264] Because of the added SCG connection to Donor 2, this message contains the BAP address assigned by Donor 2 to the migrating node. New F1-C can be established via a new transmission path (i.e., migrating node → IAB-node 2 → Donor DU 2), requiring an additional backhaul link from the migrating node to IAB-node 2. Therefore, the message also includes the BH RLC channel configuration from the migrating node to IAB-node 2. Since a new transmission path is needed (i.e., migrating node → IAB-node 2 → Donor DU 2 → Donor CU1), this message also adds (or updates) the BAP routing and BH RLC channel configuration for both F1-C and non-F1 data. If Old F1-C is transmitted via the new path, there are two transmission methods:

[0265] Method 1: Transmit F1-C traffic via SRB signaling radio bearer;

[0266] Method 2: Transmit F1-C traffic via the BH RLC channel.

[0267] Furthermore, if IAB-node 2 is added as the access anchor point for the Old F1 connection, Old F1 data is forwarded through Donor DU 2 and IAB-node 2 under Donor 2. Donor 2 configures the migrating node with a subnet address adapted to Donor DU 2. Therefore, Donor CU 2 adds an Old F1-C TNL address to the migrating node. UE F1AP signaling is sent through Old F1-C. After adding a transmission path to Old F1-C, some UE signaling can be sent through the original path, while some UE signaling can be sent through the new path.

[0268] Furthermore, the F1-U traffic of some or all UEs is also switched from the original path to the new path (i.e., migrating node → IAB-node 2 → Donor DU 2 → Donor CU 1 or Donor CU2). To reduce signaling transmission latency and minimize F1-U transmission interruption time, the RRC message may also include the TNL address of the F1-U connection, allowing the migrating node to immediately switch F1-U traffic to the new path. In addition, the BAP route and BH RLC channel mapping for the F1-U connection can be configured. For example, specifically, the message configures the BAP route used by each UE's RLC channel, and configures the mapping between the UE ID, the UE's RLC channel, and the return RLC channel of the migrating node.

[0269] In addition, there are two scenarios for the establishment of the new F1-C:

[0270] Scenario 1: The new F1-C is established immediately after the migrating node connects to Donor 2. In this case, the aforementioned RRC reconfiguration message also includes the TNL address of the new F1-C to indicate the establishment of the new F1-C.

[0271] Scenario 2: After the migrating node connects to Donor 2, it does not immediately migrate the UE. Therefore, the New F1-C can be established some time after the migrating node has completed its migration. In this case, the New F1-C's TNL address will be included in the subsequent RRC reconfiguration message. Figure 18 The RRC reconfiguration process following operation 1807.

[0272] At 1803, the Migrating node sends an RRC reconfiguration complete message to Donor CU 1, and Donor CU 1 sends a Secondary node reconfiguration complete message to Donor CU 2.

[0273] At 1804, Donor CU 2 received the message that the Secondary node reconfiguration was complete and that the migrating node's random access process was finished, and then initiated a core network path update for the migrating node.

[0274] 1805, because the data of the migrating node's New F1-C, Old F1-C, and F1-U all need to be transmitted through the new path, Donor CU 2 receives the Secondary node reconfiguration completion message and the migrating node's random access process, and then updates the BH RLC channel configuration, BAP layer routing, and BH RLC channel mapping relationship configuration for the nodes on the new path.

[0275] Operation 1805 can be executed immediately after operation 1801, but this application is not limited to this.

[0276] 1806. If Old F1-C transmits through both the original path and the new path simultaneously, Old F1-C adds a TNL address, and some or all of the UE signaling in Old F1-C is switched to the new path.

[0277] For example, Old F1-C can be transmitted via the signaling radio bearer SRB from the migrating node to IAB-node 2; or, Old F1-C can be transmitted via the BH RLC channel from the migrating node to IAB-node 2.

[0278] 1807. If operation 1802 includes TNL configuration for the F1-U connection, then the F1-U connection adds a TNL address, and the DRB of some UEs connected to the F1-U connection is switched to the new path.

[0279] 1808, Migrating node uses instructions to establish the TNL address of New F1-C with donor CU 2 to establish New F1-C.

[0280] 1809. If the RRC reconfiguration message in operation 1802 does not contain F1-U configuration information, Donor CU 1 sends an F1AP message (UE context modification) to the migrating node via the Old F1-C. This message adds the TNL address for the F1-U connection, enabling the F1-U connection to add a new path. It can also modify the BAP route and BH RLC channel mapping relationship for the F1-U connection. Specifically, it configures the BAP route used by each UE's RLC channel and the mapping relationship between the UE ID, the UE's RLC channel, and the backhaul RLC channel of the migrating node.

[0281] Operation 1809 can be executed immediately after operation 1805, but this application is not limited to this.

[0282] 1810. To migrate the UE to donor 2, a UE context is established in the new F1-C of the migrating node. This gives the UE a separate context in both the old and new F1-C. Specifically, for the UE, the migrating node has one F1AP signaling connection with both donor CU 1 and donor CU 2. The F1AP signaling connection with donor CU 1 is used to send RRC reconfiguration messages to the UE, and the F1AP signaling connection with donor CU 2 is used to receive the UE's RRC reconfiguration completion message.

[0283] There are three methods for establishing the UE context in the new F1-C of the migrating node.

[0284] Method 1: Donor CU 2 establishes a new UE context by sending an F1AP message (UE contextsetup request) to the migrating node via New F1-C. The migrating node assigns a C-RNTI to the UE and sends the C-RNTI to Donor CU2 via the UE context setup response.

[0285] In Method 1, the UE contxt setup includes the F1-U configuration for the UE's DRB. The F1-U can be configured on the donor CU1 side, in which case the UE's DRB uses the UL TNL address of the donor CU1; or it can be configured on the donor CU2 side, in which case the UE's DRB uses the UL TNL address of the donor CU2. Afterwards, the migrating node switches the UE's F1-U from the donor CU1 to the donor CU2.

[0286] Method 2: Donor CU2 sends an F1AP message, i.e., UE context modification, to the migrating node via New F1-C to establish a new UE context.

[0287] In Method 2, the UE context modification carries the UE's context identifier in the Old F1-C. The migrating node can obtain the UE context in the Old F1-C based on the UE's context identifier and use it to create a new UE context in the New F1-C.

[0288] In Method 2, since the migrating node needs to change the serving cell identifier when switching to donor 2, UEcontext modification can reconfigure the UE's serving cell identifier, and the migrating node replaces the original serving cell identifier in the UE context with this cell identifier.

[0289] In Method 2, a UE changing its serving cell may alter its C-RNTI. Therefore, the migrating node assigns a new C-RNTI to the UE and replaces the original C-RNTI with the new one. The migrating node then sends the new C-RNTI to the Donor CU2 via the UE context setup response. This method of creating a new context using the original UE context saves signaling overhead.

[0290] In Method 2, the F1-U configuration can be modified in the UE configuration modification. The modified F1-U can remain on the donor CU1 side, in which case the UE's DRB uses the UL TNL address of the donor CU1; or the F1-U can be switched from the donor CU1 side to the donor CU2 side, in which case the UE's DRB uses the UL TNL address of the donor CU2, and then the migrating node sends the UE's DRB data to the donor CU2.

[0291] Method 3: Donor CU2 establishes a new context for the UE by sending an F1 Setup Response message when establishing a new F1-C with the migrating node.

[0292] In Method 3, the F1 Setup Response can carry multiple UE context identifiers from the old F1-C. The migrating node can obtain the UE context from the old F1-C based on the UE's context identifier and use it to create a new UE context in the new F1-C. The F1 Setup Response can also contain multiple UE serving cell identifiers, which the migrating node uses to replace the serving cell identifier in the original UE context. This allows for the creation of a new context using the UE's original context during F1 setup, eliminating the need to create a context for each UE individually, thus saving signaling overhead and latency.

[0293] 1811, migrate the UE that established the context to Donor 2, and send an RRC reconfiguration message to the UE via Old F1-C.

[0294] Operation 1811 can be executed immediately after operation 1801, but this application is not limited to this.

[0295] In 1811, Old F1-C traffic can be forwarded via the original path or via a new path. For example, the sending path of the UE's RRC reconfiguration message is Donor CU 2 → Donor CU 1 → Donor DU 2 → IAB-node 2 → migratingnode.

[0296] In 1811, the RRC reconfiguration completion message of the migrated UE is forwarded to Donor CU 2 via the original path or the new path of New F1-C, for example, migrating node→IAB-node 2→Donor DU 2→Donor CU 2.

[0297] 1812, Donor CU 2 receives the RRC reconfiguration from the UE and initiates a core network path handover for the UE.

[0298] Through the method described in the above embodiments, the second Donor device configures the TNL address of the first F1-C connection via RRC messages to indicate the addition of the first F1-C connection TNL address. This allows the first F1-C traffic to be forwarded simultaneously through the DUs of both the first and second Donors, improving the flexibility of first F1-C traffic transmission. Alternatively, the second Donor device can configure the TNL address of the second F1-C connection via RRC messages, enabling the migration IAB node to establish the second F1-C connection immediately after adding an air interface connection with the second Donor device, thereby achieving UE migration. Furthermore, when establishing the UE context in the second F1-C connection, the migration node only needs to obtain the UE's first context based on the UE's first context identifier in the first F1-C connection and reuse that first context to establish the UE's second context, without using existing UE context establishment messages. This reduces signaling overhead and latency in UE context establishment, improving signaling efficiency.

[0299] In some embodiments, the migrated IAB node maintains its air interface connection with the first Donor device and adds an air interface connection with the second Donor device. The migrated node establishes a second F1-C connection before adding an air interface connection with the second Donor device. The second Donor device adds a fourth TNL address for the migrated IAB node to use for the second F1-C connection; or, it adds a fourth TNL address for the migrated IAB node to use for the second F1-C connection and a second TNL address for the migrated IAB node to use for the first F1-C connection.

[0300] For example, the second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device can forward the first RRC reconfiguration message to the migrated IAB node.

[0301] The first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a fourth TNL address for the second F1-C connection, thereby enabling the migration of the IAB node to add a fourth TNL address for the second F1-C connection; or, the first RRC reconfiguration message includes secondary cell group (SCG) configuration information, a fourth TNL address for the second F1-C connection, and a second TNL address for the first F1-C connection, thereby enabling the migration of the IAB node to add a fourth TNL address for the second F1-C connection and a second TNL address for the first F1-C connection.

[0302] According to the method of the above embodiments, the second Donor device configures the TNL address of the second F1-C connection through RRC messages, indicating the addition of the TNL address of the second F1-C connection, so that the second F1-C traffic can be forwarded through the DU of the first Donor and the second Donor at the same time, improving the forwarding flexibility of the second F1-C traffic; in addition, the second Donor device also configures the TNL address of the first F1-C connection through RRC messages, indicating the addition of the TNL address of the first F1-C connection, so that the first F1-C traffic can be forwarded through the DU of the first Donor and the second Donor at the same time, improving the forwarding flexibility of the second F1-C traffic.

[0303] In the above embodiments, the first RRC reconfiguration message may further include: a BAP address assigned to the migrated IAB node; and / or, backhaul RLC channel configuration for the secondary cell group of the migrated IAB node; a BAP route identifier and a backhaul RLC channel identifier for the second F1-C connection; a sixth TNL address added for the F1-U connection of the migrated IAB node, so that F1-U traffic can be forwarded through the DU of both the first Donor and the second Donor simultaneously; and a BAP route identifier and a backhaul RLC channel identifier for the F1-U connection of the migrated IAB node.

[0304] In the above embodiment, before the second Donor device sends the first RRC reconfiguration message for the migrated IAB node to the first Donor device, the CU of the second Donor device may also use the third TNL address or the fourth TNL address to send the first message to the DU of the migrated IAB node through the second F1-C connection, so that the migrated IAB node can establish a second context for the UE it serves based on the first message.

[0305] As an example, the first message contains the UE's first context identifier, so that the migration IAB node can obtain the UE's first context based on the first context identifier and reuse the first context to establish the UE's second context. This first message can be an F1 establishment response or a UE context modification request message.

[0306] As another example, the first message also contains the UE's serving cell configuration information so that the IAB node can be migrated to update the UE's serving cell configuration.

[0307] In the above embodiment, before the migrating IAB node receives the first RRC reconfiguration message, the first Donor device also sends a third RRC reconfiguration message to the migrating IAB node. This third RRC reconfiguration message contains a third TNL address for the second F1-C connection. Therefore, after receiving the third RRC reconfiguration message, the migrating IAB node can use the third TNL address to establish a second F1-C connection with the CU of the second Donor device, thereby enabling the migration of the UE.

[0308] In the above embodiments, during UE migration, the second Donor device can also send a second RRC reconfiguration message for the UE served by the migrating IAB node to the first Donor device, so that the first Donor device can forward the second RRC reconfiguration message to the migrating IAB node using the first TNL address via the first F1-C connection. Thus, upon receiving the second RRC reconfiguration message, the migrating IAB node can send it to the UE it serves.

[0309] In addition, the migrating IAB node can also receive a second RRC reconfiguration completion message sent by the UE it serves. If the second RRC reconfiguration completion message for the UE serving the migrating IAB node is sent before the migrating node adds an air interface connection, the second RRC reconfiguration completion message is sent to the second Donor device via the second F1-C connection using the third TNL address. If the second RRC reconfiguration completion message for the UE serving the migrating IAB node is sent after the migrating node adds an air interface connection, the second RRC reconfiguration completion message is sent to the second Donor device via the second F1-C connection using the third TNL address or the fourth TNL address.

[0310] Therefore, the second Donor device can also receive the second RRC reconfiguration completion message sent by the migrating IAB node using the aforementioned third TNL address or the aforementioned fourth TNL address via the second F1-C connection.

[0311] In the above embodiment, as an example, since the first Donor device allocates a third TNL address, the first Donor device can also send the third TNL address for migrating the IAB node to the second Donor device. Thus, the second Donor device can establish a second F1-C connection with the migrating IAB node.

[0312] In the above embodiments, as another example, the first Donor device can send a third TNL address for migrating the second F1-C connection of the IAB node to the second Donor device, and receive the second TNL address for migrating the first F1-C connection of the IAB node sent by the second Donor device, and add the second TNL address to the first F1-C connection for migrating the IAB node. Thus, the second Donor device can establish a second F1-C connection with the migrating IAB node, and add a transmission path for the first F1-C traffic on the first Donor device side, improving the flexibility of forwarding the first F1-C traffic.

[0313] In the above embodiments, the first Donor device can also receive the sixth TNL address of the F1-U connection of the migrated IAB node sent by the second Donor device, and add the sixth TNL address to the F1-U connection of the migrated IAB node. For example, the first Donor device can use the first TNL address or the second TNL address to send a second message to the migrated IAB node through the first F1-C connection. The second message may include the sixth TNL address for the F1-U connection; and / or, the BAP route identifier and the return RLC channel identifier for the F1-U connection. Thus, the migrated IAB node can update the fifth TNL address of its F1-U connection to the sixth TNL address, adding a transmission path for F1-U traffic on the first Donor device side and improving the flexibility of forwarding F1-U traffic.

[0314] Figure 19a and Figure 19b This is an example diagram illustrating an application scenario of the above embodiments. Figure 20 This is a schematic diagram of information interaction in the above embodiments. The following is in conjunction with... Figure 19a and Figure 19b and Figure 20 The above embodiments will be described.

[0315] like Figure 19a and Figure 19b As shown, when the migrating node moves from Donor 1 to Donor 2, a new transmission path is added, maintaining a dual-connection with both Donor 1 and Donor 2. Specifically, an SCG connection is established with Donor 2, and the connection with Donor 1 becomes an MCG connection. Figure 19a and Figure 19b and Figure 20 In the example, a New F1-C connection is established with Donor 2 via the original transmission path, and then a new transmission path is added to the New F1-C. A new transmission path can also be added to the Old F1-C. Because the New F1-C is established via the original path, the UE can migrate to Donor 2 before the migrating node establishes an SCG connection with Donor 2.

[0316] like Figure 20 As shown, the information interaction process includes:

[0317] In 2001, the migrating node sends a measurement report to Donor CU 1. Based on the measurement report, Donor CU 1 determines to initiate a request to add a secondary node to Donor CU 2. Donor CU 1 sends the migrating node and the context of the UE it serves to Donor CU 2. Donor CU 2 establishes the context for the migrating node in IAB-node 2, and then sends an add secondary node request response to Donor CU 1, which carries an RRCReconfiguration message.

[0318] In 2002, after receiving a response to the request to add a secondary node, Donor CU 1 sends an RRC reconfiguration message for the migrating node, carried in the response, to establish a new F1-C. The RRC reconfiguration message contains the TNL address for the new F1-C and indicates that the new F1-C should be established. The migrating node then sends an RRC reconfiguration complete message to Donor CU 1.

[0319] In 2003, because it was necessary to establish a New F1-C with Donor CU 2 through the original path (i.e., migrating node→IAB-node 1→Donor DU 1→Donor CU 2), after Donor CU 1 received the RRC reconfiguration completion message from the migrating node, it configured the BH RLC channel, BAP layer routing, and BH RLC channel mapping relationship for the nodes on the original path.

[0320] Operation 2003 can be executed immediately after operation 2001, but this application is not limited to this.

[0321] In 2004, the Migrating node used instructions to establish the TNL address of the New F1-C with the donor CU 2 to establish the New F1-C.

[0322] The New F1-C uses two transmission methods via the new path:

[0323] 1) Transmit F1-C traffic via SRB signaling radio bearer;

[0324] 2) Transmit F1-C traffic through the BH RLC channel.

[0325] In 2005, to migrate the UE to donor 2, a UE context was established in the new F1-C of the migrating node. This resulted in the UE having a separate context in both the original and new F1-C. Specifically, for the UE, the migrating node had one F1AP signaling connection with both donor CU1 and donor CU2. The F1AP signaling connection with donor CU1 was used to send RRC reconfiguration messages to the UE, while the F1AP signaling connection with donor CU2 was used to receive the UE's RRC reconfiguration completion message.

[0326] There are three methods to establish the UE context in the migrating node's New F1-C:

[0327] Method 1: Donor CU 2 sends an F1AP message, i.e., UE context setup request, to the migrating node via New F1-C to establish a new UE context.

[0328] In Method 1, the Migrating node assigns a C-RNTI to the UE and sends the C-RNTI to the Donor CU2 via the UE context setup response.

[0329] In Method 1, the UE contxt setup request includes the F1-U configuration for the UE's DRB. The F1-U can be configured on the donor CU1 side, in which case the UE's DRB uses the UL TNL address of the donor CU1; or it can be configured on the donor CU2 side, in which case the UE's DRB uses the UL TNL address of the donor CU2. Afterwards, the migrating node will switch the UE's F1-U from the donor CU1 to the donor CU2.

[0330] Method 2: Donor CU2 sends an F1AP message, i.e., UE context modification, to the migrating node via New F1-C to establish a new UE context.

[0331] In Method 2, the UE context modification carries the UE's context identifier in the Old F1-C. The migrating node can obtain the UE context under the Old F1-C based on the UE's context identifier and use it to create a new UE context in the New F1-C.

[0332] In Method 2, since the migrating node needs to change the serving cell identifier when migrating to donor 2, the UE context modification message can configure the UE's serving cell identifier, and the migrating node replaces the original serving cell identifier in the UE context with this cell identifier.

[0333] In Method 2, a UE changing its serving cell may alter its C-RNTI. Therefore, the migrating node assigns a new C-RNTI to the UE, replacing the original C-RNTI. The migrating node then sends the new C-RNTI to the Donor CU2 via the UE context setup response. This method of creating a new context using the original UE context saves signaling overhead.

[0334] In Method 2, the F1-U configuration can be modified in the UE configuration modification. The modified F1-U can remain on the donor CU1 side, in which case the UE's DRB uses the UL TNL address of the donor CU1; or the F1-U can be switched from the donor CU1 side to the donor CU2 side, in which case the UE's DRB uses the UL TNL address of the donor CU2, and then the migrating node sends the UE's DRB data to the donor CU2.

[0335] In particular, if the UE's F1-U switches from Donor CU 1 to Donor CU 2 during operation 2005, it needs to transmit F1-U traffic with Donor CU 2 through the original path, that is, the transmission path is: migrating node→IAB-node 1→DonorDU 1→Donor CU 2.

[0336] Method 3: Donor CU2 establishes a new context for the UE by sending an F1 Setup Response message when establishing a new F1-C with the migrating node.

[0337] In Method 3, the F1 Setup Response can carry the context identifiers of multiple UEs in the old F1-C. The migrating node can obtain the UE context under the old F1-C based on the UE's context identifier and use it to create a new UE context in the new F1-C. The F1 Setup Response can also contain the serving cell identifiers of multiple UEs, and the migrating node replaces the serving cell identifier in the original UE context with this cell identifier. In this way, a new context is created using the original UE context during F1 setup, eliminating the process of creating each UE context separately, which can save signaling overhead and signaling latency.

[0338] In 2006, the UE that established the context was migrated to Donor 2. Donor CU 1 sent an RRC reconfiguration message to the UE through the original path of Old F1-C, that is, Donor CU 1 → Donor DU 1 → IAB-node 1 → migrating node.

[0339] Operation 2006 can be executed immediately after operation 2001, but this application is not limited to this.

[0340] In Operation 2006, after migration, the UE sends an RRC reconfiguration complete message to Donor CU 2 via New F1-C. If the RRC reconfiguration complete message is sent before adding a new air interface connection, it must be forwarded through Donor DU 1 and IAB-node 1 under Donor 1, i.e., the transmission path is: migrating node→IAB-node 1→Donor DU 1→Donor CU 2; if the RRC reconfiguration complete message is sent after adding a new air interface connection, it can be forwarded through the DUs of both Donor 1 and Donor 2.

[0341] In 2007, after Donor CU 2 received the RRC reconfiguration completion message from the UE, it initiated a core network path handover for the UE.

[0342] In 2008, Donor CU 1 sent an RRCReconfiguration message carried in the response to the request to add a secondary node to the migrating node.

[0343] Because of the added SCG connection to Donor 2, this message contains the BAP address assigned by Donor 2 to the migrating node. New F1-C traffic is transmitted via a new transmission path (i.e., migrating node → IAB-node2 → Donor DU 2), adding a backhaul link from the migrating node to IAB-node 2; therefore, the message also includes the BH RLC channel configuration from the migrating node to IAB-node 2. Furthermore, due to the need to add a new transmission path (i.e., migrating node → IAB-node 2 → Donor DU 2 → Donor CU1), this message also adds (or updates) the BAP routing and BH RLC channel configuration for both F1-C and non-F1 data.

[0344] If Old F1-C traffic is transmitted via the new path, there are two transmission methods:

[0345] Method 1: Transmit F1-C traffic via SRB signaling radio bearer;

[0346] Method 2: Transmit F1-C traffic via the BH RLC channel.

[0347] Furthermore, to add IAB-node 2 as the access anchor point for F1 connections, and to forward F1 data through DonorDU 2 and IAB-node 2 under Donor 2, the migrating node needs to be configured with a subnet address adapted to Donor DU 2. Therefore, Donor CU 2 needs to add an F1-C TNL address for the migrating node.

[0348] In other words, when the UE's F1AP signaling is sent through the New F1-C, if the New F1-C should add a TNL address and add a path, then some of the UE's signaling can be sent through the original path and some of the UE's signaling can be sent through the new path.

[0349] In 2008, F1-U traffic for some or all UEs was also redirected from the original path to a new path (i.e., migratingnode → IAB-node 2 → Donor DU 2 → Donor CU 1 or Donor CU2). To reduce signaling transmission latency and minimize F1-U transmission interruptions, the RRC message can also include the TNL address for the F1-U connection, allowing the migratingnode to immediately switch F1-U traffic to the new path. In addition, BAP routes and BH RLC channel mappings for F1-U connections can be configured. Specifically, the message configures the BAP routes used for each UE's RLC channels, and configures the mapping between the UE ID, the UE's RLC channel, and the return RLC channel of the migrating node.

[0350] In 2009, the Migrating node sent an RRC reconfiguration complete message to Donor CU 1, and Donor CU 1 sent a Secondary node reconfiguration complete message to Donor CU 2.

[0351] In 2010, after Donor CU 2 received the completion of the secondary node reconfiguration and the random access request from the migrating node, it initiated a core network path update for the migrating node.

[0352] In 2011, because the new F1-C and F1-U data of the migrating node needed to be transmitted through the new path, after Donor CU 2 received the Secondary node reconfiguration completion message and the random access request from the migrating node, it updated the BH RLC channel configuration, BAP layer routing, and BH RLC channel mapping relationship configuration for the nodes on the new path.

[0353] Operation 2011 can be executed immediately after operation 2001, but this application is not limited to this.

[0354] In 2012, the New F1-C added a TNL address, and some or all UE signaling of the New F1-C was switched to the new path. If the Old F1-C traffic could be transmitted through the new path, the Old F1-C added a TNL address, and some or all UE signaling of the Old F1-C was switched to the new path.

[0355] For example, Old F1-C traffic can be transmitted via the signaling radio bearer SRB from the migrating node to IAB-node 2; or, Old F1-C traffic can be transmitted via the BH RLC channel from the migrating node to IAB-node 2.

[0356] In 2013, if Operation 2008 includes a TNL configuration for an F1-U connection, then the F1-U connection adds a TNL address, and the migrating node will transfer the DRB of some UEs connected to the F1-U connection to the new path.

[0357] According to the method of the above embodiments, when the migrated IAB node adds an air interface connection with the second Donor device, the second Donor device configures the TNL address of the second F1-C connection through an RRC message, indicating the addition of the TNL address of the second F1-C connection. This allows the second F1-C traffic to be forwarded through the DU of both the first and second Donors simultaneously, improving the forwarding flexibility of the second F1-C traffic. Additionally, the second Donor device also configures the TNL address of the first F1-C connection through an RRC message, indicating the addition of the TNL address of the first F1-C connection. This allows the first F1-C traffic to be forwarded through the DU of both the first and second Donors simultaneously, further improving the forwarding flexibility of the second F1-C traffic. Furthermore, when establishing a UE context in the second F1-C connection, the migrated node only needs to obtain the first context of the UE based on the first context identifier of the UE in the first F1-C connection and reuse the first context to establish the second context of the UE, without using existing UE context establishment messages. This reduces signaling overhead and latency in UE context establishment, improving signaling efficiency.

[0358] It is worth noting that the above appendix Figure 9-20 The embodiments described herein are merely illustrative and are not limited thereto. For example, the execution order of various operations can be appropriately adjusted, and additional operations can be added or some operations can be removed. Those skilled in the art can make appropriate modifications based on the above description, and are not limited to the above-described embodiments. Figure 9-20 The records.

[0359] Furthermore, the above embodiments are merely illustrative examples of embodiments of this application, but this application is not limited thereto, and appropriate modifications can be made based on the above embodiments. For example, the above embodiments can be used alone, or one or more of the above embodiments can be combined.

[0360] According to the method of the embodiments of this application, as described above, on the one hand, load balancing between Donor devices can be achieved, and on the other hand, the forwarding paths of the original F1-C connection and the new F1-C connection are optimized.

[0361] Second aspect of the embodiments

[0362] This application provides a group migration device.

[0363] Figure 21 This is a schematic diagram of a group migration apparatus according to an embodiment of this application. The apparatus may be, for example, a Donor device in an IAB system, or one or more components or parts configured within that Donor device. The IAB system includes Donor devices and IAB nodes. IAB nodes move from a first Donor device to a second Donor device. This embodiment is described from the perspective of the second Donor device. The implementation principle of the group migration apparatus in this embodiment is similar to the implementation of the second Donor device in the first aspect embodiment; the identical details will not be repeated.

[0364] like Figure 21 As shown, the group migration device 2100 of this application embodiment includes:

[0365] Processing unit 2101, when migrating an IAB node from a first Donor device to a second Donor device, the second Donor device performs at least one of the following processes:

[0366] The migration IAB node updates the first TNL address of the first F1-C connection to the second TNL address;

[0367] The migration IAB node updates the third TNL address of the second F1-C connection to the fourth TNL address;

[0368] Configure the migrated IAB node with a fourth TNL address for establishing the second F1-C connection;

[0369] Add a second TNL address for the first F1-C connection to the migrated IAB node;

[0370] Configure the migrating IAB node with a third TNL address for establishing the second F1-C connection;

[0371] Add a fourth TNL address for the second F1-C connection to the migrated IAB node;

[0372] Wherein, the first F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, the second F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the second Donor device, the first TNL address and the third TNL address are TNL addresses that can be routed to the DU of the first Donor device, and the second TNL address and the fourth TNL address are TNL addresses that can be routed to the DU of the second Donor device.

[0373] In this embodiment of the application, migrating an IAB node from a first Donor device to a second Donor device refers to one of the following situations:

[0374] Scenario 1: When the backhaul RLC link of the migrated IAB node under the first Donor device fails, it re-establishes a connection to the second Donor device.

[0375] Scenario 2: The migration IAB node switches from the first Donor device to the second Donor device;

[0376] Scenario 3: The migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device.

[0377] In scenario one, when the backhaul RLC link of the migrated IAB node under the first Donor device fails, the processing unit 2101 performs the following processing:

[0378] The migration IAB node updates the first TNL address of the first F1-C connection to the second TNL address; and

[0379] Configure the migrated IAB node with a fourth TNL address for establishing the second F1-C connection.

[0380] In the above embodiment, after the migrated IAB node is re-established to the second Donor device, the processing unit 2101 sends a first RRC reconfiguration message to the migrated IAB node. The first RRC reconfiguration message includes a second TNL address for the first F1-C connection, or the first RRC reconfiguration message includes a second TNL address for the first F1-C connection and a fourth TNL address for the second F1-C connection.

[0381] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0382] The BAP address assigned to the migrated IAB node;

[0383] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0384] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0385] BAP routing identifier and backhaul RLC channel identifier used for F1-U connection

[0386] The fifth TNL address is a TNL address that can be routed to the DU of the first Donor device, and the sixth TNL address is a TNL address that can be routed to the DU of the second Donor device.

[0387] In the above embodiments, if the first RRC reconfiguration message does not contain the fourth TNL address used for the second F1-C connection, after the second Donor device sends the first RRC reconfiguration message to the migration IAB node, the processing unit sends a third RRC reconfiguration message to the IAB node, wherein the third RRC reconfiguration message contains the fourth TNL address used for the second F1-C connection.

[0388] In the above embodiment, after the second Donor device establishes the second F1-C connection with the migration IAB node, the processing unit 2101 (e.g., the CU configured in the second Donor device) uses the fourth TNL address to send a first message to the DU of the migration IAB node through the second F1-C connection, so that the migration IAB node establishes a second context for the UE it serves.

[0389] In some embodiments, the first message includes a first context identifier of the UE, so that the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0390] In some embodiments, the first message may further include the serving cell configuration information of the UE.

[0391] In some embodiments, the processing unit 2101 sends a second RRC reconfiguration message to the first Donor device for the UE serving the migrated IAB node, so that the first Donor device forwards the second RRC reconfiguration message to the migrated IAB node using the second TNL address through the first F1-C connection; in addition, the processing unit 2101 also receives a second RRC reconfiguration completion message sent by the migrated IAB node using the fourth TNL address through the second F1-C connection.

[0392] In scenario two, when the migration IAB node switches from the first Donor device to the second Donor device, the processing unit 2101 performs the following processing:

[0393] Configure the migrating IAB node with a fourth TNL address for establishing the second F1-C connection; or,

[0394] Configure the migration IAB node with a fourth TNL address for establishing the second F1-C connection, and cause the migration IAB node to update the first TNL address of the first F1-C connection to the second TNL address.

[0395] In some embodiments, the processing unit 2101 sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node; the first RRC reconfiguration message includes a handover command and a fourth TNL address for the second F1-C connection, or the first RRC reconfiguration message includes a handover command and a second TNL address for the first F1-C connection.

[0396] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0397] The BAP address assigned to the migrated IAB node;

[0398] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0399] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0400] BAP routing identifier and backhaul RLC channel identifier used for the F1-U connection of the migrated IAB node;

[0401] The fifth TNL address is a TNL address that can be routed to the DU of the first Donor device, and the sixth TNL address is a TNL address that can be routed to the DU of the second Donor device.

[0402] In some embodiments, if the first RRC reconfiguration message does not contain the fourth TNL address for the second F1-C connection, after the migration IAB node switches to the second Donor, the processing unit 2101 sends a third RRC reconfiguration message to the migration IAB node, wherein the third RRC reconfiguration message contains the fourth TNL address for the second F1-C connection.

[0403] In some embodiments, after the second Donor device establishes the second F1-C connection with the migration IAB node, the processing unit 2101 (e.g., the CU configured in the second Donor device) uses the fourth TNL address to send a first message to the DU of the migration IAB node through the second F1-C connection, so that the migration IAB node establishes a second context for the UE it serves.

[0404] In some embodiments, the first message includes a first context identifier of the UE, so that the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0405] In other embodiments, the first message also includes the serving cell configuration information of the UE.

[0406] In some embodiments, the processing unit 2101 sends a second RRC reconfiguration message to the first Donor device for the UE serving the migrated IAB node, so that the first Donor device forwards the second RRC reconfiguration message to the migrated IAB node using the second TNL address or the first TNL address via the first F1-C connection; in addition, the processing unit 2101 also receives a second RRC reconfiguration completion message sent by the migrated IAB node using the fourth TNL address via the second F1-C connection.

[0407] In scenario two, when the migration IAB node switches from the first Donor device to the second Donor device, the second Donor device performs the following processing:

[0408] The migration IAB node updates the third TNL address used for the second F1-C connection to the fourth TNL address.

[0409] In some embodiments, the processing unit 2101 sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node. The first RRC reconfiguration message includes a handover command and the fourth TNL address for the second F1-C connection.

[0410] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0411] The BAP address assigned to the migrated IAB node;

[0412] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0413] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0414] The BAP routing identifier and backhaul RLC channel identifier used for the F1-U connection of the migrated IAB node

[0415] The fifth TNL address is a TNL address that can be routed to the DU of the first Donor device, and the sixth TNL address is a TNL address that can be routed to the DU of the second Donor device.

[0416] In some embodiments, before the second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, the processing unit 2101 (e.g., a CU configured in the second Donor device) uses the third TNL address to send a first message to the migrated IAB node DU via the second F1-C connection, so that the migrated IAB node establishes a second context for the UE it serves.

[0417] In some embodiments, the first message includes a first context identifier of the UE, so that the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0418] In other embodiments, the first message also includes the serving cell configuration information of the UE.

[0419] In some embodiments, the processing unit 2101 sends a second RRC reconfiguration message for the UE to the first Donor device, so that the first Donor device forwards the second RRC reconfiguration message to the migrating IAB node using the first TNL address through the first F1-C connection; in addition, the processing unit 2101 also receives a second RRC reconfiguration completion message sent by the migrating IAB node using the third TNL address through the second F1-C connection; or, receives a second RRC reconfiguration completion message sent by the migrating IAB node using the fourth TNL address through the second F1-C connection.

[0420] In scenario three, if the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the processing unit 2101 performs the following processing:

[0421] Add a second TNL address for the first F1-C connection to the migrated IAB node.

[0422] In some embodiments, the processing unit 2101 sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node; the first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection.

[0423] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0424] The BAP address assigned to the migrated IAB node;

[0425] Configuration of the backhaul RLC channel for the secondary cell group of the migrated IAB node;

[0426] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0427] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0428] The BAP routing identifier and backhaul RLC channel identifier are used for the F1-U connection of the migrated IAB node.

[0429] In scenario three, if the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the processing unit 2101 performs the following processing:

[0430] Configure the migrating IAB node with a fourth TNL address or a third TNL address for establishing the second F1-C connection; or,

[0431] Add a second TNL address for the first F1-C connection to the migrated IAB node.

[0432] In some embodiments, the processing unit 2101 sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node; the first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a fourth TNL address or a third TNL address for the second F1-C connection, or the first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection.

[0433] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0434] The BAP address assigned to the migrated IAB node;

[0435] Configuration of the backhaul RLC channel for the secondary cell group of the migrated IAB node;

[0436] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0437] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0438] The BAP routing identifier and backhaul RLC channel identifier are used for the F1-U connection of the migrated IAB node.

[0439] In some embodiments, if the first RRC reconfiguration message does not contain the fourth TNL address for the second F1-C connection, after the migrating IAB node adds an air interface connection with the second Donor device, the processing unit 2101 sends a third RRC reconfiguration message to the migrating IAB node, wherein the third RRC reconfiguration message contains the fourth TNL address for the second F1-C connection.

[0440] In some embodiments, after the second Donor device establishes the second F1-C connection with the migration IAB node, the processing unit 2101 (e.g., the CU configured in the second Donor device) uses the third TNL address or the fourth TNL address to send a first message to the migration IAB node through the second F1-C connection, so that the migration IAB node establishes a second context for the UE it serves.

[0441] In some embodiments, the first message includes a first context identifier of the UE, so that the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0442] In other embodiments, the first message also includes the serving cell configuration information of the UE.

[0443] In some embodiments, the processing unit 2101 sends a second RRC reconfiguration message for the UE to the first Donor device, so that the first Donor device forwards the second RRC reconfiguration message to the migrating IAB node using the first TNL address or the second TNL address through the first F1-C connection; the processing unit 2101 also receives a second RRC reconfiguration completion message sent by the migrating IAB node using the third TNL address through the second F1-C connection; or, receives a second RRC reconfiguration completion message sent by the migrating IAB node using the fourth TNL address through the second F1-C connection.

[0444] In scenario three, if the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the processing unit 2101 performs the following processing:

[0445] Add a fourth TNL address for the second F1-C connection to the migrated IAB node; or,

[0446] A fourth TNL address for the second F1-C connection is added to the migrated IAB node, and a second TNL address for the first F1-C connection is added to the migrated IAB node.

[0447] In some embodiments, the processing unit 2101 sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node. The first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a fourth TNL address for the second F1-C connection. Alternatively, the first RRC reconfiguration message includes secondary cell group (SCG) configuration information, a fourth TNL address for the second F1-C connection, and a second TNL address for the first F1-C connection.

[0448] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0449] The BAP address assigned to the migrated IAB node;

[0450] Configuration of the backhaul RLC channel for the secondary cell group of the migrated IAB node;

[0451] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0452] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0453] The BAP routing identifier and backhaul RLC channel identifier are used for the F1-U connection of the migrated IAB node.

[0454] In some embodiments, before the second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, the processing unit 2101 (e.g., the CU configured in the second Donor device) uses the third TNL address or the fourth TNL address to send a first message to the DU of the migrated IAB node via the second F1-C connection, so that the migrated IAB node establishes a second context for the UE it serves.

[0455] In some embodiments, the first message includes a first context identifier of the UE, so that the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0456] In other embodiments, the first message also includes the serving cell configuration information of the UE.

[0457] In some embodiments, the processing unit 2101 sends a second RRC reconfiguration message for the UE to the first Donor device, so that the first Donor device forwards the second RRC reconfiguration message to the migrating IAB node using the first TNL address through the first F1-C connection; the processing unit 2101 also receives a second RRC reconfiguration completion message sent by the migrating IAB node using the third TNL address through the second F1-C connection; or, receives a second RRC reconfiguration completion message sent by the migrating IAB node using the fourth TNL address through the second F1-C connection.

[0458] It is worth noting that the above description only covers the components or modules relevant to this application, but this application is not limited thereto. The group migration apparatus 2100 of this application embodiment may also include other components or modules, and for details of these components or modules, please refer to related technologies.

[0459] In addition, for the sake of simplicity, Figure 21 The diagram only exemplifies the connection relationships or signal flow between various components or modules; however, those skilled in the art should understand that various related technologies, such as bus connections, can be employed. The aforementioned components or modules can be implemented using hardware facilities such as processors, memory, transmitters, and receivers; this application does not impose any limitations on this.

[0460] According to the embodiments of this application, as described above, on the one hand, load balancing between Donor devices can be achieved, and on the other hand, the forwarding paths of the original F1-C connection and the new F1-C connection are optimized.

[0461] Third aspect of the embodiments

[0462] This application provides a group migration device.

[0463] Figure 22 This is a schematic diagram of a group migration apparatus according to an embodiment of this application. The apparatus can be, for example, an IAB node in an IAB system, or one or more components or parts configured within that IAB node. The IAB system includes Donor devices and IAB nodes. An IAB node moves from a first Donor device to a second Donor device; this IAB node is called a migration IAB node. This embodiment of the application describes the migration IAB node from one side. The implementation principle of the group migration apparatus in this embodiment is similar to that of the migration IAB node in the first aspect embodiment; the identical parts will not be repeated.

[0464] like Figure 22 As shown, the group migration device 2200 of this application embodiment includes:

[0465] The receiving unit 2201 receives a first RRC reconfiguration message sent by the second Donor device from the first Donor device. The first RRC reconfiguration message includes at least one of the following:

[0466] A second TNL address is used for the first F1-C connection to update the first TNL address of the first F1-C connection to the second TNL address, or to add the second TNL address to the first F1-C connection.

[0467] The fourth TNL address is used for the second F1-C connection to update the third TNL address of the second F1-C connection to the fourth TNL address, or to establish the second F1-C connection with the CU of the second Donor device using the fourth TNL address, or to add the fourth TNL address to the second F1-C connection;

[0468] The third TNL address is used for the second F1-C connection, to add the third TNL address to the second F1-C connection, or to use the third TNL address to establish the second F1-C connection with the CU of the second Donor device;

[0469] Wherein, the first F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, the second F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the second Donor device, the first TNL address and the third TNL address are TNL addresses that can be routed to the DU of the first Donor device, and the second TNL address and the fourth TNL address are TNL addresses that can be routed to the DU of the second Donor device.

[0470] In some embodiments, the migration of the IAB node from the first Donor device to the second Donor device refers to one of the following situations:

[0471] Scenario 1: When the backhaul RLC link of the migrated IAB node under the first Donor device fails, it re-establishes a connection to the second Donor device.

[0472] Scenario 2: The migration IAB node switches from the first Donor device to the second Donor device;

[0473] Scenario 3: The migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device.

[0474] In scenario one, after the migrated IAB node is re-established to the second Donor device, the receiving unit 2201 receives the first RRC reconfiguration message;

[0475] The first RRC reconfiguration message contains a second TNL address for the first F1-C connection, and the migration IAB node updates the first TNL address of the first F1-C connection to the second TNL address;

[0476] Alternatively, the first RRC reconfiguration message includes a second TNL address for the first F1-C connection and a fourth TNL address for the second F1-C connection. The migration IAB node updates the first TNL address of the first F1-C connection to the second TNL address and uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0477] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0478] The BAP address assigned to the migrated IAB node;

[0479] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0480] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0481] BAP routing identifier and backhaul RLC channel identifier used for F1-U connection

[0482] The fifth TNL address is a TNL address that can be routed to the DU of the first Donor device, and the sixth TNL address is a TNL address that can be routed to the DU of the second Donor device.

[0483] In some embodiments, if the first RRC reconfiguration message does not contain the fourth TNL address for the second F1-C connection, after receiving the first RRC reconfiguration message, the receiving unit 2201 also receives a third RRC reconfiguration message sent by the second Donor device, wherein the third RRC reconfiguration message contains the fourth TNL address for the second F1-C connection.

[0484] In the above embodiments, such as Figure 22 As shown, the device 2200 further includes:

[0485] The first establishment unit 2202 uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0486] In some embodiments, the first establishing unit 2202 establishes a second F1-C connection with the second Donor device; the receiving unit 2201 receives a first message sent by the CU of the second Donor device through the second F1-C connection using the fourth TNL address.

[0487] In the above embodiments, such as Figure 22 As shown, the device 2200 further includes:

[0488] The second establishment unit 2203 establishes a second context for the UE it serves based on the first message.

[0489] In some embodiments, the first message includes a first context identifier of the UE, and the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0490] In some embodiments, the first message may further include the serving cell configuration information of the UE.

[0491] In some embodiments, such as Figure 22 As shown, the device 2200 also includes a transmitting unit 2204.

[0492] In the above embodiment, the receiving unit 2201 receives a second RRC reconfiguration message for the UE serving the migrated IAB node, forwarded by the first Donor device using the second TNL address through the first F1-C connection, and the sending unit 2204 sends the second RRC reconfiguration message to the UE it serves.

[0493] In the above embodiment, the receiving unit 2201 also receives a second RRC reconfiguration completion message sent by the UE it serves, and the sending unit 2204 uses the fourth TNL address to send the second RRC reconfiguration completion message to the second Donor device through the second F1-C connection.

[0494] In some embodiments, the receiving unit 2201 receives a second message sent by the first Donor device using the second TNL address through the first F1-C connection. The second message includes a sixth TNL address for the F1-U connection, or includes a sixth TNL address for the F1-U connection and a BAP route identifier and a backhaul RLC channel identifier for the F1-U connection.

[0495] In the above embodiments, such as Figure 22 As shown, the device 2200 also includes:

[0496] Processing unit 2205 updates the fifth TNL address of the F1-U connection to the sixth TNL address.

[0497] In scenario two, when the migration IAB node switches from the first Donor device to the second Donor device, the receiving unit 2201 receives the first RRC reconfiguration message.

[0498] In some embodiments, the first RRC reconfiguration message includes a switching command and a fourth TNL address for the second F1-C connection, then the first establishment unit 2202 uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0499] In some embodiments, if the first RRC reconfiguration message includes a switching command and a second TNL address for the first F1-C connection, then the processing unit 2205 updates the first TNL address of the first F1-C connection to the second TNL address.

[0500] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0501] The BAP address assigned to the migrated IAB node;

[0502] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0503] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0504] The BAP routing identifier and backhaul RLC channel identifier are used for the F1-U connection of the migrated IAB node.

[0505] In some embodiments, if the first RRC reconfiguration message does not contain the fourth TNL address for the second F1-C connection, after the migration IAB node switches to the second Donor device, the receiving unit 2201 receives a third RRC reconfiguration message sent by the second Donor device, wherein the third RRC reconfiguration message contains the fourth TNL address for the second F1-C connection; the first establishing unit 2202 uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0506] In some embodiments, the receiving unit 2201 receives a second RRC reconfiguration message for the UE migrating IAB service, which is forwarded by the first Donor device using the second TNL address or using the first TNL address through the first F1-C connection, and the sending unit 2204 sends the second RRC reconfiguration message to the UE it serves.

[0507] In the above embodiment, the receiving unit 2201 receives the second RRC reconfiguration completion message sent by the UE served by the IAB node, and the sending unit 2204 uses the fourth TNL address to send the second RRC reconfiguration completion message to the second Donor device through the second F1-C connection.

[0508] In some embodiments, if the first RRC reconfiguration message contains the second TNL address, the receiving unit 2201 receives a second message sent by the first Donor device using the second TNL address through the first F1-C connection. The second message contains a sixth TNL address for the F1-U connection, or contains a sixth TNL address for the F1-U connection and a BAP route identifier and a return RLC channel identifier for the F1-U connection.

[0509] The processing unit 2205 updates the fifth TNL address of the F1-U connection to the sixth TNL address.

[0510] In scenario two, when the migration IAB node switches from the first Donor device to the second Donor device, the receiving unit 2201 receives the first RRC reconfiguration message, which includes a switching command and a fourth TNL address for the second F1-C connection; the processing unit 2205 updates the third TNL address of the second F1-C connection to the fourth TNL address.

[0511] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0512] The BAP address assigned to the migrated IAB node;

[0513] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0514] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0515] The BAP routing identifier and backhaul RLC channel identifier are used for the F1-U connection of the migrated IAB node.

[0516] In some embodiments, before the migration IAB node receives the first RRC reconfiguration message, the receiving unit 2201 receives a third RRC reconfiguration message sent by the first Donor device, wherein the third RRC reconfiguration message includes a third TNL address for the second F1-C connection; the first establishing unit 2202 uses the third TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0517] In some embodiments, the receiving unit 2201 receives a second RRC reconfiguration message for the UE serving the migrated IAB node, forwarded by the first Donor device using the first TNL address through the first F1-C connection, and the sending unit 2204 sends the second RRC reconfiguration message to the UE it serves.

[0518] In the above embodiment, the receiving unit 2201 receives the second RRC reconfiguration complete message sent by the UE served by the IAB node, and the sending unit 2204 uses the third TNL address or the fourth TNL address to send the second RRC reconfiguration complete message to the second Donor device through the second F1-C connection.

[0519] In scenario three, when the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the receiving unit 2201 receives the first RRC reconfiguration message; wherein, the first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection, and the processing unit 2205 adds the second TNL address to the first F1-C connection.

[0520] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0521] The BAP address assigned to the migrated IAB node;

[0522] The backhaul RLC channel configuration for the migrated IAB node;

[0523] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0524] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0525] BAP routing identifier and backhaul RLC channel identifier used for the F1-U connection of the migrated IAB node;

[0526] The sixth TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0527] In scenario three, when the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the receiving unit 2201 receives the first RRC reconfiguration message.

[0528] In some embodiments, the first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a fourth TNL address or a third TNL address for the second F1-C connection. The first establishment unit 2202 uses the fourth TNL address or the third TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0529] In some embodiments, the first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection, and the processing unit 2205 adds the second TNL address to the first F1-C.

[0530] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0531] The BAP address assigned to the migrated IAB node;

[0532] The backhaul RLC channel configuration for the migrated IAB node;

[0533] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0534] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0535] BAP routing identifier and backhaul RLC channel identifier used for the F1-U connection of the migrated IAB node;

[0536] The sixth TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0537] In scenario three, if the first RRC reconfiguration message does not contain the fourth TNL address used for the second F1-C connection, after the migrating IAB node adds an air interface connection with the second Donor device, the receiving unit 2201 receives a third RRC reconfiguration message sent by the second Donor device, wherein the third RRC reconfiguration message contains the fourth TNL address used for the second F1-C connection; the first establishing unit 2202 uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0538] In some embodiments, the receiving unit 2201 receives a second RRC reconfiguration message for the UE serving the migrated IAB node, forwarded by the first Donor device using the first TNL address or the second TNL address through the first F1-C connection, and sends the second RRC reconfiguration message to the UE it serves.

[0539] In the above embodiment, the receiving unit 2201 receives the second RRC reconfiguration completion message sent by the UE served by the IAB node, and the sending unit 2204 uses the third TNL address or the fourth TNL address to send the second RRC reconfiguration completion message to the second Donor device through the second F1-C connection.

[0540] In scenario three, when the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the receiving unit 2201 receives the first RRC reconfiguration message.

[0541] In some embodiments, the first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a fourth TNL address for the second F1-C connection, and the processing unit 2205 adds the fourth TNL address to the second F1-C connection.

[0542] In some embodiments, the first RRC reconfiguration message includes secondary cell group (SCG) configuration information, a fourth TNL address for the second F1-C connection, and a second TNL address for the first F1-C connection. The processing unit 2205 adds the fourth TNL address to the second F1-C connection and adds the second TNL address to the first F1-C connection.

[0543] In some embodiments, the first RRC reconfiguration message further includes at least one of the following:

[0544] The BAP address assigned to the migrated IAB node;

[0545] The backhaul RLC channel configuration for the migrated IAB node;

[0546] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0547] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0548] BAP routing identifier and backhaul RLC channel identifier used for the F1-U connection of the migrated IAB node;

[0549] The sixth TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0550] In some embodiments, before the receiving unit 2201 receives the first RRC reconfiguration message, the receiving unit 2201 receives a third RRC reconfiguration message sent by the first Donor device, wherein the third RRC reconfiguration message contains a third TNL address for the second F1-C connection; the first establishing unit 2201 uses the third TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0551] In some embodiments, the receiving unit 2201 receives a second RRC reconfiguration message for the UE serving the migrated IAB node, forwarded by the first Donor device using the first TNL address through the first F1-C connection, and the sending unit 2204 sends the second RRC reconfiguration message to the UE it serves.

[0552] In the above embodiment, the receiving unit 2201 receives the second RRC reconfiguration completion message sent by the UE served by the IAB node, and the sending unit 2204 uses the third TNL address or the fourth TNL address to send the second RRC reconfiguration completion message to the second Donor device through the second F1-C connection.

[0553] It is worth noting that the above description only covers the components or modules relevant to this application, but this application is not limited thereto. The resource allocation device 2200 in this application embodiment may also include other components or modules, and for details regarding these components or modules, please refer to related technologies.

[0554] In addition, for the sake of simplicity, Figure 22The diagram only exemplifies the connection relationships or signal flow between various components or modules; however, those skilled in the art should understand that various related technologies, such as bus connections, can be employed. The aforementioned components or modules can be implemented using hardware facilities such as processors, memory, transmitters, and receivers; this application does not impose any limitations on this.

[0555] According to the embodiments of this application, as described above, on the one hand, load balancing between Donor devices can be achieved, and on the other hand, the forwarding paths of the original F1-C connection and the new F1-C connection are optimized.

[0556] Fourth aspect of the embodiment

[0557] This application provides a group migration apparatus. The apparatus may be, for example, a Donor device in an IAB system, or one or more components or parts configured within that Donor device. The IAB system includes Donor devices and IAB nodes. An IAB node moves from a first Donor device to a second Donor device. This application embodiment is described from the perspective of the first Donor device. The implementation principle of the group migration apparatus in this application embodiment is similar to that of the first Donor device implementation in the first aspect embodiment; the identical details will not be repeated.

[0558] Figure 23 This is a schematic diagram of a group migration device according to an embodiment of this application, such as... Figure 23 As shown, the group migration device 2300 of this application embodiment includes:

[0559] The receiving unit 2301 receives the second TNL address of the first F1-C connection of the migrated IAB node sent by the second Donor device;

[0560] Processing unit 2302 updates the first TNL address of the first F1-C connection of the migrated IAB node to the second TNL address, or adds the second TNL address to the first F1-C connection of the migrated IAB node;

[0561] Wherein, the first F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, the first TNL address is the TNL address of the DU that can be routed to the first Donor device, and the second TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0562] In this embodiment of the application, the migration of the IAB node from the first Donor device to the second Donor device refers to one of the following situations:

[0563] Scenario 1: When the backhaul RLC link of the migrated IAB node under the first Donor device fails, it re-establishes a connection to the second Donor device.

[0564] Scenario 2: The migration IAB node switches from the first Donor device to the second Donor device;

[0565] Scenario 3: The above-mentioned migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device.

[0566] In some embodiments, the receiving unit 2301 receives the sixth TNL address of the F1-U connection of the migrated IAB node sent by the second Donor device;

[0567] The processing unit 2302 updates the fifth TNL address of the F1-U connection of the migrated IAB node to the sixth TNL address, or adds the sixth TNL address to the F1-U connection of the migrated IAB node;

[0568] The fifth TNL address is the TNL address of the DU that can be routed to the first Donor device, and the sixth TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0569] In some embodiments, such as Figure 23 As shown, the device 2300 further includes:

[0570] The sending unit 2303 uses the first TNL address to send a second message to the migrating IAB node through the first F1-C connection. The second message includes a sixth TNL address for the F1-U connection of the migrating IAB node and / or a BAP route identifier and a return RLC channel identifier for the F1-U connection of the migrating IAB node.

[0571] In some embodiments, the receiving unit 2301 receives a second RRC reconfiguration message sent by the second Donor device for a UE serving the migration IAB node; the sending unit 2303 uses the second TNL address to send the second RRC reconfiguration message to the migration IAB node through the first F1-C connection, so that the migration IAB node forwards the second RRC reconfiguration message to the UE it serves.

[0572] In some embodiments, when the migrating IAB node switches from the first Donor device to the second Donor device (Case 2), before the processing unit 2302 updates the first TNL address of the first F1-C connection of the migrating IAB node to the second TNL address, the receiving unit 2301 receives a second RRC reconfiguration message sent by the second Donor device for the UE served by the migrating IAB node; the sending unit 2303 uses the first TNL address to send the second RRC reconfiguration message to the migrating IAB node through the first F1-C connection, so that the migrating IAB node forwards the second RRC reconfiguration message to the UE it serves.

[0573] Figure 24 This is another schematic diagram of the group migration device according to an embodiment of this application, such as... Figure 24 As shown, the group migration device 2400 of this application embodiment includes:

[0574] The sending unit 2401 sends a third TNL address to the second Donor device for establishing a second F1-C connection of the migrated IAB node; wherein the second F1-C connection is an F1 connection between the DU of the IAB node and the CU of the second Donor device, and the third TNL address is a TNL address of the DU that can be routed to the first Donor device.

[0575] In some embodiments, moving the IAB node from the first Donor device to the second Donor device means one of the following:

[0576] Scenario 2: The migration IAB node switches from the first Donor device to the second Donor device;

[0577] Scenario 3: The migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device.

[0578] In some embodiments, such as Figure 24 As shown, the device 2400 further includes:

[0579] The receiving unit 2402 receives the second TNL address sent by the second Donor for the first F1-C connection of the migrated IAB node;

[0580] Processing unit 2403 adds the second TNL address to the first F1-C connection of the migrated IAB node.

[0581] Wherein, the second TNL address is the TNL address of the DU that can be routed to the second Donor device, and the first F1-C connection is the F1 connection between the DU of the IAB node and the CU of the first Donor device.

[0582] In some embodiments, the receiving unit 2402 receives the sixth TNL address of the F1-U connection of the migrated IAB node sent by the second Donor device; the processing unit 2403 updates the fifth TNL address of the F1-U connection of the migrated IAB node to the sixth TNL address or adds the sixth TNL address to the F1-U connection of the migrated IAB node; wherein, the fifth TNL address is the TNL address of the DU that can be routed to the second Donor device, and the sixth TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0583] In some embodiments, the sending unit 2401 sends a third RRC reconfiguration message to the migrating IAB node, wherein the third RRC reconfiguration message includes the third TNL address, so that the migrating IAB node establishes a second F1-C connection with the CU of the second Donor device.

[0584] In some embodiments, the receiving unit 2402 receives a second RRC reconfiguration message sent by the second Donor device for a UE served by the migration IAB node; the sending unit 2401 sends the second RRC reconfiguration message to the migration IAB node via a first F1-C connection using a first TNL address or a second TNL address, so that the migration IAB node forwards the second RRC reconfiguration message to the UE it serves; wherein, the first TNL address is a TNL address of a DU that can be routed to the first Donor device, and the second TNL address is a TNL address of a DU that can be routed to the second Donor device.

[0585] In some embodiments, the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device (Case 3). The sending unit 2401 sends a second message to the migrating IAB node through the first F1-C connection using either the first TNL address or the second TNL address. The second message includes at least one of the following: a sixth TNL address for the F1-U connection; a BAP route identifier and a return RLC channel identifier for the F1-U connection.

[0586] It is worth noting that the above description only covers the components or modules relevant to this application, but this application is not limited thereto. The resource allocation device 2300 / 2400 of the embodiments of this application may also include other components or modules, and for details of these components or modules, please refer to related technologies.

[0587] In addition, for the sake of simplicity, Figure 23 and Figure 24 The diagram only exemplifies the connection relationships or signal flow between various components or modules; however, those skilled in the art should understand that various related technologies, such as bus connections, can be employed. The aforementioned components or modules can be implemented using hardware facilities such as processors, memory, transmitters, and receivers; this application does not impose any limitations on this.

[0588] According to the embodiments of this application, as described above, on the one hand, load balancing between Donor devices can be achieved, and on the other hand, the forwarding paths of the original F1-C connection and the new F1-C connection are optimized.

[0589] Fifth aspect of the embodiment

[0590] This application provides a communication system. Figure 25 This is a schematic diagram of the 2500 communication system, as shown below. Figure 25 As shown, the communication system 2500 includes Donor devices 2501 and 2502, IAB nodes 2503 and 2504, and terminal device 2505. IAB node 2503 is a migrating IAB node, Donor device 2501 is the source Donor device (first Donor device) of IAB node 2503, and Donor device 2502 is the target Donor device (second Donor device) of IAB node 2503. IAB node 2504 and terminal device 2505 are provided with services by IAB node 2503.

[0591] For simplicity, Figure 25 This illustration uses only two Donor devices, two IAB nodes, and one terminal device as an example, but the embodiments in this application are not limited to this. For details regarding the network architecture of the Donor devices, IAB nodes, and the terminal device, please refer to relevant technologies; descriptions are omitted here.

[0592] In some embodiments, the Donor device 2501 is configured to perform the method performed by the first Donor device in the first aspect embodiment, which may include... Figure 23 or Figure 24 The apparatus. In some embodiments, the Donor device 2502 is configured to perform the method performed by the second Donor device in the first aspect embodiment, which may include... Figure 21The apparatus. In some embodiments, the IAB node 2503 is configured to perform the method performed in the implementation of the first aspect of migrating the IAB node, which may include... Figure 22 The apparatus. For details regarding Donor devices 2501 and 2502 and IAB node 2503, please refer to the embodiments in the first to fourth aspects, which are omitted here.

[0593] This application also provides an IAB node.

[0594] Figure 26 This is a schematic diagram of an IAB node according to an embodiment of this application. Figure 26 As shown, the IAB node 2600 may include a processor 2601 and a memory 2602; the memory 2602 stores data and programs and is coupled to the processor 2601. It is worth noting that this diagram is exemplary; other types of structures may be used to supplement or replace this structure to implement telecommunications functions or other functions.

[0595] For example, processor 2601 can be configured to execute a program to implement the method performed by migrating IAB nodes as in the embodiment of the first aspect.

[0596] like Figure 26 As shown, the IAB node 2600 may further include: a communication module 2603, an input unit 2604, a display 2605, and a power supply 2606. The functions of these components are similar to those in the prior art and will not be described in detail here. It is worth noting that the IAB node 2600 is not necessarily required to include these components. Figure 26 All of the components shown are not required; furthermore, the IAB node 2600 may also include... Figure 26 For components not shown, please refer to existing technologies.

[0597] This application also provides a Donor device.

[0598] Figure 27 This is a schematic diagram of the Donor device according to an embodiment of this application. Figure 27 As shown, the Donor device 2700 may include a processor (e.g., a central processing unit, CPU) 2701 and a memory 2702; the memory 2702 is coupled to the processor 2701. The memory 2702 can store various types of data; it also stores information processing programs and executes these programs under the control of the central processing unit 2701.

[0599] For example, processor 2701 can be configured to execute a program to implement the method performed by the first or second Donor device as in the embodiment of the first aspect.

[0600] In addition, such as Figure 27 As shown, the Donor device 2700 may also include a transceiver 2703 and an antenna 2704, etc.; the functions of these components are similar to those in the prior art, and will not be described in detail here. It is worth noting that the Donor device 2700 is not necessarily required to include these components. Figure 27 All components shown; in addition, the Donor device 2700 may also include Figure 27 For components not shown, please refer to existing technologies.

[0601] This application also provides a computer-readable program, wherein when the program is executed in an IAB node, the program causes the computer to perform the method performed in the first aspect embodiment of migrating an IAB node.

[0602] This application also provides a storage medium storing a computer-readable program, wherein the computer-readable program causes a computer to execute the method performed in the first aspect embodiment of migrating an IAB node.

[0603] This application also provides a computer-readable program, wherein when the program is executed in a Donor device, the program causes the computer to perform the method performed by the first Donor device or the second Donor device in the embodiments of the first aspect.

[0604] This application also provides a storage medium storing a computer-readable program, wherein the computer-readable program causes a computer to perform the method executed by the first or second Donor device in the first aspect embodiment in a Donor device.

[0605] The apparatus and methods described above in this application can be implemented in hardware or in combination with software. This application relates to a computer-readable program that, when executed by a logic component, enables the logic component to implement the apparatus or components described above, or to implement the various methods or steps described above. Logic components include, for example, field-programmable logic devices (FPGAs), microprocessors, and processors used in computers. This application also relates to storage media for storing the above programs, such as hard disks, magnetic disks, optical disks, DVDs, and flash memory.

[0606] The methods / apparatus described in conjunction with the embodiments of this application can be directly embodied in hardware, software modules executed by a processor, or a combination of both. For example, one or more and / or combinations of one or more functional block diagrams shown in the figures can correspond to various software modules in a computer program flow, or to various hardware modules. These software modules can correspond to the various steps shown in the figures, respectively. These hardware modules can be implemented, for example, using a field-programmable gate array (FPGA) to embed these software modules.

[0607] The software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. A storage medium can be coupled to the processor, enabling the processor to read information from and write information to the storage medium; or the storage medium can be an integral part of the processor. The processor and storage medium can reside in an ASIC. The software module can be stored in the memory of a mobile terminal or in a memory card that can be inserted into the mobile terminal. For example, if the device (such as a mobile terminal) uses a high-capacity MEGA-SIM card or a high-capacity flash memory device, the software module can be stored in the MEGA-SIM card or the high-capacity flash memory device.

[0608] One or more and / or one or more combinations of functional blocks described in the accompanying drawings can be implemented as a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, or any suitable combination thereof for performing the functions described herein. One or more and / or one or more combinations of functional blocks described in the accompanying drawings can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in communication with a DSP, or any other such configuration.

[0609] The present application has been described above with reference to specific embodiments. However, those skilled in the art should understand that these descriptions are exemplary and not intended to limit the scope of protection of the present application. Those skilled in the art can make various modifications and variations to the present application based on its spirit and principles, and these modifications and variations are also within the scope of the present application.

[0610] Regarding the above-described embodiments disclosed in this example, the following notes are also disclosed:

[0611] 1. A group migration method, wherein the method includes:

[0612] When migrating an IAB node from a first Donor to a second Donor device, the second Donor device performs at least one of the following processes:

[0613] The migration IAB node updates the first TNL address of the first F1-C connection to the second TNL address;

[0614] The migration IAB node updates the third TNL address of the second F1-C connection to the fourth TNL address;

[0615] Configure the migrated IAB node with a fourth TNL address for establishing the second F1-C connection;

[0616] Add a second TNL address for the first F1-C connection to the migrated IAB node;

[0617] Configure the migrating IAB node with a third TNL address for establishing the second F1-C connection;

[0618] Add a fourth TNL address for the second F1-C connection to the migrated IAB node;

[0619] Wherein, the first F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, the second F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the second Donor device, the first TNL address and the third TNL address are TNL addresses that can be routed to the DU of the first Donor device, and the second TNL address and the fourth TNL address are TNL addresses that can be routed to the DU of the second Donor device.

[0620] 2. According to the method described in Appendix 1, the migration of the IAB node from the first Donor device to the second Donor device refers to one of the following situations:

[0621] When the backhaul RLC link of the migrated IAB node fails under the first Donor device, it re-establishes a wireless link with the second Donor device.

[0622] The migration IAB node is switched from the first Donor device to the second Donor device;

[0623] The migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device.

[0624] 3. According to the method described in Appendix 2, when a radio link failure occurs on the backhaul RLC link of the migrated IAB node under the first Donor device, the second Donor device performs the following processing:

[0625] The migration IAB node updates the first TNL address of the first F1-C connection to the second TNL address; and

[0626] Configure the migrated IAB node with a fourth TNL address for establishing the second F1-C connection.

[0627] 4. The method according to Appendix 3, wherein the method comprises:

[0628] After the migrated IAB node is re-established to the second Donor device, the second Donor device sends a first RRC reconfiguration message to the migrated IAB node. The first RRC reconfiguration message contains a second TNL address for the first F1-C connection, or the first RRC reconfiguration message contains a second TNL address for the first F1-C connection and a fourth TNL address for the second F1-C connection.

[0629] 5. The method according to Appendix 4, wherein the first RRC reconfiguration message further comprises at least one of the following:

[0630] The BAP address assigned to the migrated IAB node;

[0631] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0632] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0633] BAP routing identifier and backhaul RLC channel identifier used for F1-U connection

[0634] The fifth TNL address is a TNL address that can be routed to the DU of the first Donor device, and the sixth TNL address is a TNL address that can be routed to the DU of the second Donor device.

[0635] 6. The method according to Appendix 4, wherein, if the first RRC reconfiguration message does not contain the fourth TNL address for the second F1-C connection, after the second Donor device sends the first RRC reconfiguration message to the migration IAB node, the method further includes:

[0636] The second Donor device sends a third RRC reconfiguration message to the IAB node, wherein the third RRC reconfiguration message contains a fourth TNL address for the second F1-C connection.

[0637] 6a. The method according to Appendix 4 or 6, wherein after the second Donor device establishes the second F1-C connection with the migration IAB node, the method further includes:

[0638] The CU of the second Donor device uses the fourth TNL address to send a first message to the DU of the migrating IAB node through the second F1-C connection, so that the migrating IAB node can establish a second context for the UE it serves.

[0639] 7. The method according to Appendix 6, wherein the first message contains a first context identifier of the UE, so that the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0640] 7a. The method according to Appendix 7, wherein the first message further includes the serving cell configuration information of the UE.

[0641] 7b. The method according to Appendix 4 or 6, wherein the method further comprises:

[0642] The second Donor device sends a second RRC reconfiguration message to the first Donor device for the UE serving the migrated IAB node, so that the first Donor device can use the second TNL address to forward the second RRC reconfiguration message to the migrated IAB node through the first F1-C connection;

[0643] The second Donor device receives the second RRC reconfiguration complete message sent by the migrated IAB node using the fourth TNL address through the second F1-C connection.

[0644] 8. The method according to Appendix 2, wherein, in the case of the migration IAB node switching from the first Donor device to the second Donor device, the second Donor device performs the following processing:

[0645] Configure the migrating IAB node with a fourth TNL address for establishing the second F1-C connection; or,

[0646] Configure the migration IAB node with a fourth TNL address for establishing the second F1-C connection, and cause the migration IAB node to update the first TNL address of the first F1-C connection to the second TNL address.

[0647] 9. The method according to Appendix 2, wherein, in the case of the migration IAB node switching from the first Donor device to the second Donor device, the second Donor device performs the following processing:

[0648] The migration IAB node updates the third TNL address used for the second F1-C connection to the fourth TNL address.

[0649] 10. The method according to Appendix 8, wherein the method comprises:

[0650] The second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node; the first RRC reconfiguration message includes a handover command and a fourth TNL address for the second F1-C connection, or the first RRC reconfiguration message includes a handover command and a second TNL address for the first F1-C connection.

[0651] 11. The method according to Appendix 10, wherein the first RRC reconfiguration message further comprises at least one of the following:

[0652] The BAP address assigned to the migrated IAB node;

[0653] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0654] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0655] BAP routing identifier and backhaul RLC channel identifier used for the F1-U connection of the migrated IAB node;

[0656] The fifth TNL address is a TNL address that can be routed to the DU of the first Donor device, and the sixth TNL address is a TNL address that can be routed to the DU of the second Donor device.

[0657] 12. The method according to Appendix 10, wherein if the first RRC reconfiguration message does not contain the fourth TNL address for the second F1-C connection, after the migration IAB node switches to the second Donor, the method further includes:

[0658] The second Donor device sends a third RRC reconfiguration message to the migrating IAB node, wherein the third RRC reconfiguration message contains a fourth TNL address for the second F1-C connection.

[0659] 12a. The method according to Appendix 10 or 12, wherein after the second Donor device establishes the second F1-C connection with the migration IAB node, the method further includes:

[0660] The CU of the second Donor device uses the fourth TNL address to send a first message to the DU of the migrating IAB node through the second F1-C connection, so that the migrating IAB node can establish a second context for the UE it serves.

[0661] 13. The method according to Appendix 12, wherein the first message contains a first context identifier of the UE, so that the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0662] 13a. The method according to Appendix 13, wherein the first message further includes serving cell configuration information of the UE.

[0663] 14. The method according to Appendix 10, wherein the method further comprises:

[0664] The second Donor device sends a second RRC reconfiguration message to the first Donor device for the UE serving the migrated IAB node, so that the first Donor device can forward the second RRC reconfiguration message to the migrated IAB node using the second TNL address or using the first TNL address through the first F1-C connection;

[0665] The second Donor device receives the second RRC reconfiguration complete message sent by the migrated IAB node using the fourth TNL address through the second F1-C connection.

[0666] 15. The method according to Appendix 9, wherein the method comprises:

[0667] The second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node. The first RRC reconfiguration message includes a handover command and the fourth TNL address for the second F1-C connection.

[0668] 16. The method according to Appendix 15, wherein the first RRC reconfiguration message further comprises at least one of the following:

[0669] The BAP address assigned to the migrated IAB node;

[0670] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0671] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0672] The BAP routing identifier and backhaul RLC channel identifier used for the F1-U connection of the migrated IAB node

[0673] The fifth TNL address is a TNL address that can be routed to the DU of the first Donor device, and the sixth TNL address is a TNL address that can be routed to the DU of the second Donor device.

[0674] 16a. The method according to Appendix 15, wherein, before the second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, the method further comprises:

[0675] The CU of the second Donor device uses the third TNL address to send a first message to the migration IAB node DU through the second F1-C connection, so that the migration IAB node can establish a second context for the UE it serves.

[0676] 16b. The method according to Appendix 16a, wherein the first message contains a first context identifier of the UE, so that the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0677] 16c. The method according to Appendix 16b, wherein the first message further includes serving cell configuration information of the UE.

[0678] 16d. The method according to Appendix 15, wherein the method further comprises:

[0679] The second Donor device sends a second RRC reconfiguration message for the UE to the first Donor device, so that the first Donor device can use the first TNL address to forward the second RRC reconfiguration message to the migration IAB node through the first F1-C connection;

[0680] The second Donor device receives a second RRC reconfiguration complete message sent by the migrating IAB node using the third TNL address through the second F1-C connection; or, receives a second RRC reconfiguration complete message sent by the migrating IAB node using the fourth TNL address through the second F1-C connection.

[0681] 17. According to the method described in Appendix 2, wherein, when the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the second Donor device performs the following processing:

[0682] Add a second TNL address for the first F1-C connection to the migrated IAB node.

[0683] 18. According to the method described in Appendix 2, wherein, when the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the second Donor device performs the following processing:

[0684] Configure the migrating IAB node with a fourth TNL address or a third TNL address for establishing the second F1-C connection; or,

[0685] Add a second TNL address for the first F1-C connection to the migrated IAB node.

[0686] 19. The method according to Appendix 2, wherein, when the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the second Donor device performs the following processing:

[0687] Add a fourth TNL address for the second F1-C connection to the migrated IAB node; or,

[0688] A fourth TNL address for the second F1-C connection is added to the migrated IAB node, and a second TNL address for the first F1-C connection is added to the migrated IAB node.

[0689] 20. The method according to Appendix 17, wherein the method comprises:

[0690] The second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node; the first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection.

[0691] 21. The method according to Appendix 20, wherein the first RRC reconfiguration message further includes at least one of the following:

[0692] The BAP address assigned to the migrated IAB node;

[0693] Configuration of the backhaul RLC channel for the secondary cell group of the migrated IAB node;

[0694] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0695] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0696] The BAP routing identifier and backhaul RLC channel identifier are used for the F1-U connection of the migrated IAB node.

[0697] 22. The method according to Appendix 18, wherein the method comprises:

[0698] The second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node; the first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a fourth TNL address or a third TNL address for the second F1-C connection, or the first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection.

[0699] 23. According to the method described in Appendix 22, the first RRC reconfiguration message further includes at least one of the following:

[0700] The BAP address assigned to the migrated IAB node;

[0701] Configuration of the backhaul RLC channel for the secondary cell group of the migrated IAB node;

[0702] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0703] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0704] The BAP routing identifier and backhaul RLC channel identifier are used for the F1-U connection of the migrated IAB node.

[0705] 24. The method according to Appendix 22, wherein, if the first RRC reconfiguration message does not contain the fourth TNL address for the second F1-C connection, after the migrating IAB node adds an air interface connection with the second Donor device, the method further includes:

[0706] The second Donor device sends a third RRC reconfiguration message to the migrating IAB node, wherein the third RRC reconfiguration message contains a fourth TNL address for the second F1-C connection.

[0707] 24a. The method according to Appendix 22 or 24, wherein after the second Donor device establishes the second F1-C connection with the migration IAB node, the method further includes:

[0708] The CU of the second Donor device uses the third TNL address or the fourth TNL address to send a first message to the migration IAB node through the second F1-C connection, so that the migration IAB node can establish a second context for the UE it serves.

[0709] 25. The method according to Appendix 24a, wherein the first message contains a first context identifier of the UE, so that the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0710] 25a. The method according to Appendix 25, wherein the first message further includes serving cell configuration information of the UE.

[0711] 26. The method according to Appendix 22 or 24, further comprising:

[0712] The second Donor device sends a second RRC reconfiguration message for the UE to the first Donor device, so that the first Donor device can forward the second RRC reconfiguration message to the migration IAB node using the first TNL address or the second TNL address through the first F1-C connection;

[0713] The second Donor device receives a second RRC reconfiguration complete message sent by the migrating IAB node using the third TNL address through the second F1-C connection; or, receives a second RRC reconfiguration complete message sent by the migrating IAB node using the fourth TNL address through the second F1-C connection.

[0714] 27. The method according to Appendix 19, wherein the method comprises:

[0715] The second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, so that the first Donor device forwards the first RRC reconfiguration message to the migrated IAB node. The first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a fourth TNL address for the second F1-C connection, or the first RRC reconfiguration message includes secondary cell group (SCG) configuration information, a fourth TNL address for the second F1-C connection, and a second TNL address for the first F1-C connection.

[0716] 28. The method according to Appendix 27, wherein the first RRC reconfiguration message further includes at least one of the following:

[0717] The BAP address assigned to the migrated IAB node;

[0718] Configuration of the backhaul RLC channel for the secondary cell group of the migrated IAB node;

[0719] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0720] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0721] The BAP routing identifier and backhaul RLC channel identifier are used for the F1-U connection of the migrated IAB node.

[0722] 29. The method according to Appendix 27, wherein, before the second Donor device sends a first RRC reconfiguration message for the migrated IAB node to the first Donor device, the method further comprises:

[0723] The CU of the second Donor device uses the third TNL address or the fourth TNL address to send a first message to the DU of the migration IAB node through the second F1-C connection, so that the migration IAB node can establish a second context for the UE it serves.

[0724] 29a. The method according to Appendix 29, wherein the first message contains a first context identifier of the UE, so that the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0725] 30. The method according to Appendix 29a, wherein the first message further includes the serving cell configuration information of the UE.

[0726] 31. The method according to Appendix 27, wherein the method further comprises:

[0727] The second Donor device sends a second RRC reconfiguration message for the UE to the first Donor device, so that the first Donor device can use the first TNL address to forward the second RRC reconfiguration message to the migration IAB node through the first F1-C connection;

[0728] The second Donor device receives a second RRC reconfiguration complete message sent by the migrating IAB node using the third TNL address through the second F1-C connection; or, receives a second RRC reconfiguration complete message sent by the migrating IAB node using the fourth TNL address through the second F1-C connection.

[0729] 32. A group migration method, the method being applied to migrating IAB nodes from a first Donor device to a second Donor device, wherein the method comprises:

[0730] The migration IAB node receives a first RRC reconfiguration message sent by the second Donor device from the first Donor device, and the first RRC reconfiguration message includes at least one of the following:

[0731] A second TNL address is used for the first F1-C connection to update the first TNL address of the first F1-C connection to the second TNL address, or to add the second TNL address to the first F1-C connection.

[0732] The fourth TNL address is used for the second F1-C connection to update the third TNL address of the second F1-C connection to the fourth TNL address, or to establish the second F1-C connection with the CU of the second Donor device using the fourth TNL address, or to add the fourth TNL address to the second F1-C connection;

[0733] The third TNL address is used for the second F1-C connection, to add the third TNL address to the second F1-C connection, or to use the third TNL address to establish the second F1-C connection with the CU of the second Donor device;

[0734] Wherein, the first F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, the second F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the second Donor device, the first TNL address and the third TNL address are TNL addresses that can be routed to the DU of the first Donor device, and the second TNL address and the fourth TNL address are TNL addresses that can be routed to the DU of the second Donor device.

[0735] 33. The method according to Appendix 32, wherein the migration of the IAB node from the first Donor device to the second Donor device refers to one of the following:

[0736] When the backhaul RLC link of the migrated IAB node fails under the first Donor device, it re-establishes a wireless link with the second Donor device.

[0737] The migration IAB node is switched from the first Donor device to the second Donor device;

[0738] The migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device.

[0739] 34. The method according to Appendix 33, wherein after the migration IAB node is re-established to the second Donor device, the migration IAB node receives the first RRC reconfiguration message;

[0740] The first RRC reconfiguration message contains a second TNL address for the first F1-C connection, and the migration IAB node updates the first TNL address of the first F1-C connection to the second TNL address;

[0741] Alternatively, the first RRC reconfiguration message includes a second TNL address for the first F1-C connection and a fourth TNL address for the second F1-C connection. The migration IAB node updates the first TNL address of the first F1-C connection to the second TNL address and uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0742] 35. The method according to Appendix 34, wherein the first RRC reconfiguration message further includes at least one of the following:

[0743] The BAP address assigned to the migrated IAB node;

[0744] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0745] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0746] BAP routing identifier and backhaul RLC channel identifier used for F1-U connection

[0747] The fifth TNL address is a TNL address that can be routed to the DU of the first Donor device, and the sixth TNL address is a TNL address that can be routed to the DU of the second Donor device.

[0748] 36. The method according to Appendix 34, wherein, if the first RRC reconfiguration message does not contain the fourth TNL address for the second F1-C connection, after the migration IAB node receives the first RRC reconfiguration message, the method further includes:

[0749] The migrating IAB node receives a third RRC reconfiguration message sent by the second Donor device, wherein the third RRC reconfiguration message contains a fourth TNL address for the second F1-C connection;

[0750] The migrated IAB node uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0751] 36a. The method according to Appendix 34 or 36, wherein the method further comprises:

[0752] The migration IAB node establishes a second F1-C connection with the second Donor device and receives a first message sent by the CU of the second Donor device through the second F1-C connection using the fourth TNL address;

[0753] The migration IAB node establishes a second context for the UE it serves based on the first message.

[0754] 37. The method according to Appendix 36, wherein the first message contains a first context identifier of the UE, and the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

[0755] 38. The method according to Appendix 37, wherein the first message further includes the serving cell configuration information of the UE.

[0756] 39. The method according to Appendix 34 or 36, wherein the method further comprises:

[0757] The migrating IAB node receives a second RRC reconfiguration message for a UE served by the migrating IAB node, forwarded by the first Donor device using the second TNL address through the first F1-C connection, and sends the second RRC reconfiguration message to the UE it serves.

[0758] The migration IAB node receives the second RRC reconfiguration complete message sent by the UE it serves, and uses the fourth TNL address to send the second RRC reconfiguration complete message to the second Donor device through the second F1-C connection.

[0759] 40. The method according to Appendix 34 or 36, wherein the method further comprises:

[0760] The migration IAB node receives a second message sent by the first Donor device using the second TNL address through the first F1-C connection. The second message contains a sixth TNL address for the F1-U connection, or contains a sixth TNL address for the F1-U connection as well as a BAP route identifier and a backhaul RLC channel identifier for the F1-U connection.

[0761] The migration IAB node updates the fifth TNL address of the F1-U connection to the sixth TNL address.

[0762] 41. The method according to Appendix 33, wherein, in the case of the migration IAB node switching from the first Donor device to the second Donor device, the migration IAB node receives the first RRC reconfiguration message;

[0763] The first RRC reconfiguration message includes a switching command and a fourth TNL address for the second F1-C connection. The migrating IAB node uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0764] Alternatively, the first RRC reconfiguration message may include a switching command and a second TNL address for the first F1-C connection, and the migrating IAB node may update the first TNL address of the first F1-C connection to the second TNL address.

[0765] 42. The method according to Appendix 41, wherein the first RRC reconfiguration message further includes at least one of the following:

[0766] The BAP address assigned to the migrated IAB node;

[0767] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0768] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0769] The BAP routing identifier and backhaul RLC channel identifier are used for the F1-U connection of the migrated IAB node.

[0770] 43. The method according to Appendix 41, wherein, if the first RRC reconfiguration message does not contain the fourth TNL address for the second F1-C connection, after the migration IAB node switches to the second Donor device, the method further includes:

[0771] The IAB node receives a third RRC reconfiguration message sent by the second Donor device, wherein the third RRC reconfiguration message contains a fourth TNL address for the second F1-C connection;

[0772] The migrated IAB node uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0773] 43a. The method according to Appendix 41 or 43, wherein the method further comprises:

[0774] The migration IAB node receives a second RRC reconfiguration message for the UE serving the migration IAB service, forwarded by the first Donor device using the second TNL address or using the first TNL address through the first F1-C connection, and sends the second RRC reconfiguration message to the UE it serves.

[0775] The migration IAB node receives the second RRC reconfiguration complete message sent by the UE it serves, and uses the fourth TNL address to send the second RRC reconfiguration complete message to the second Donor device through the second F1-C connection.

[0776] 44. The method according to Appendix 41, wherein if the first RRC reconfiguration message contains the second TNL address, the method further includes:

[0777] The migration IAB node receives a second message sent by the first Donor device using the second TNL address through the first F1-C connection. The second message contains a sixth TNL address for the F1-U connection, or contains a sixth TNL address for the F1-U connection as well as a BAP route identifier and a backhaul RLC channel identifier for the F1-U connection.

[0778] The migration IAB node updates the fifth TNL address of the F1-U connection to the sixth TNL address.

[0779] 45. The method according to Appendix 33, wherein, in the case of the migration IAB node switching from the first Donor device to the second Donor device, the migration IAB node receives the first RRC reconfiguration message, the first RRC reconfiguration message containing a switching command and a fourth TNL address for the second F1-C connection;

[0780] The migration IAB node updates the third TNL address of the second F1-C connection to the fourth TNL address.

[0781] 46. ​​The method according to Appendix 45, wherein the first RRC reconfiguration message further includes at least one of the following:

[0782] The BAP address assigned to the migrated IAB node;

[0783] The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 data;

[0784] The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address;

[0785] The BAP routing identifier and backhaul RLC channel identifier are used for the F1-U connection of the migrated IAB node.

[0786] 47. The method according to Appendix 45, wherein, before the migration IAB node receives the first RRC reconfiguration message, the method further comprises:

[0787] The migrating IAB node receives a third RRC reconfiguration message sent by the first Donor device, wherein the third RRC reconfiguration message contains a third TNL address for the second F1-C connection;

[0788] The migrated IAB node uses the third TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0789] 47a. The method according to Appendix 47, wherein the method further comprises:

[0790] The migrating IAB node receives a second RRC reconfiguration message for the UE served by the migrating IAB node, forwarded by the first Donor device using the first TNL address through the first F1-C connection, and sends the second RRC reconfiguration message to the UE it serves.

[0791] The migration IAB node receives the second RRC reconfiguration complete message sent by the UE it serves, and sends the second RRC reconfiguration complete message to the second Donor device through the second F1-C connection using the third TNL address or the fourth TNL address.

[0792] 48. The method according to Appendix 33, wherein, when the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the migrating IAB node receives the first RRC reconfiguration message;

[0793] The first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection. The migration IAB node adds the second TNL address to the first F1-C connection.

[0794] 49. The method according to Appendix 48, wherein the first RRC reconfiguration message further includes at least one of the following:

[0795] The BAP address assigned to the migrated IAB node;

[0796] The backhaul RLC channel configuration for the migrated IAB node;

[0797] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0798] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0799] BAP routing identifier and backhaul RLC channel identifier used for the F1-U connection of the migrated IAB node;

[0800] The sixth TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0801] 50. The method according to Appendix 33, wherein, when the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the migrating IAB node receives the first RRC reconfiguration message;

[0802] The first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a fourth TNL address or a third TNL address for the second F1-C connection. The migrating IAB node uses the fourth TNL address or the third TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0803] Alternatively, the first RRC reconfiguration message may include secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection, and the migration IAB node may add the second TNL address to the first F1-C connection.

[0804] 51. The method according to Appendix 50, wherein the first RRC reconfiguration message further includes at least one of the following:

[0805] The BAP address assigned to the migrated IAB node;

[0806] The backhaul RLC channel configuration for the migrated IAB node;

[0807] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0808] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0809] BAP routing identifier and backhaul RLC channel identifier used for the F1-U connection of the migrated IAB node;

[0810] The sixth TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0811] 52. The method according to Appendix 50, wherein, if the first RRC reconfiguration message does not contain the fourth TNL address for the second F1-C connection, after the migrating IAB node adds an air interface connection with the second Donor device, the method further includes:

[0812] The migrating IAB node receives a third RRC reconfiguration message sent by the second Donor device, wherein the third RRC reconfiguration message contains a fourth TNL address for the second F1-C connection;

[0813] The migrated IAB node uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0814] 52a. The method according to Appendix 50 or 52, wherein the method further comprises:

[0815] The migrating IAB node receives a second RRC reconfiguration message for the UE served by the migrating IAB node, forwarded by the first Donor device using the first TNL address or the second TNL address through the first F1-C connection, and sends the second RRC reconfiguration message to the UE it serves.

[0816] The migration IAB node receives the second RRC reconfiguration complete message sent by the UE it serves, and sends the second RRC reconfiguration complete message to the second Donor device through the second F1-C connection using the third TNL address or the fourth TNL address.

[0817] 53. The method according to Appendix 33, wherein, when the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the migrating IAB node receives the first RRC reconfiguration message;

[0818] The first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a fourth TNL address for the second F1-C connection. The migration IAB node adds the fourth TNL address to the second F1-C connection.

[0819] Alternatively, the first RRC reconfiguration message includes secondary cell group (SCG) configuration information, a fourth TNL address for the second F1-C connection, and a second TNL address for the first F1-C connection. The migrating IAB node adds the fourth TNL address to the second F1-C connection and adds the second TNL address to the first F1-C connection.

[0820] 54. The method according to Appendix 53, wherein the first RRC reconfiguration message further includes at least one of the following:

[0821] The BAP address assigned to the migrated IAB node;

[0822] The backhaul RLC channel configuration for the migrated IAB node;

[0823] BAP routing identifier and backhaul RLC channel identifier used for the second F1-C connection;

[0824] The sixth TNL address is added to the F1-U connection of the migrated IAB node;

[0825] BAP routing identifier and backhaul RLC channel identifier used for the F1-U connection of the migrated IAB node;

[0826] The sixth TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0827] 55. The method according to Appendix 53, wherein, before the migration IAB node receives the first RRC reconfiguration message, the method further comprises:

[0828] The migrating IAB node receives a third RRC reconfiguration message sent by the first Donor device, wherein the third RRC reconfiguration message contains a third TNL address for the second F1-C connection;

[0829] The migrated IAB node uses the third TNL address to establish the second F1-C connection with the CU of the second Donor device.

[0830] 56. The method according to Appendix 53, wherein the method further comprises:

[0831] The migrating IAB node receives a second RRC reconfiguration message for the UE served by the migrating IAB node, forwarded by the first Donor device using the first TNL address through the first F1-C connection, and sends the second RRC reconfiguration message to the UE it serves.

[0832] The migration IAB node receives the second RRC reconfiguration complete message sent by the UE it serves, and sends the second RRC reconfiguration complete message to the second Donor device through the second F1-C connection using the third TNL address or the fourth TNL address.

[0833] 57. A group migration method, the method being applied to a first Donor device, migrating IAB nodes from the first Donor device to a second Donor device, wherein the method comprises:

[0834] The first Donor device receives the second TNL address of the first F1-C connection of the migrated IAB node sent by the second Donor device;

[0835] The first Donor device updates the first TNL address of the first F1-C connection of the migrated IAB node to the second TNL address, or adds the second TNL address to the first F1-C connection of the migrated IAB node;

[0836] Wherein, the first F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, the first TNL address is the TNL address of the DU that can be routed to the first Donor device, and the second TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0837] 57a. The method according to Appendix 57, wherein migrating the IAB node from the first Donor device to the second Donor device means one of the following:

[0838] When the backhaul RLC link of the migrated IAB node fails under the first Donor device, it re-establishes a wireless link with the second Donor device.

[0839] The migration IAB node switches from the first Donor device to the second Donor device.

[0840] The aforementioned migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device.

[0841] 58. The method according to Appendix 57a, wherein the method further comprises:

[0842] The first Donor device receives the sixth TNL address of the F1-U connection of the migrated IAB node sent by the second Donor device;

[0843] The first Donor device updates the fifth TNL address of the F1-U connection of the migrated IAB node to the sixth TNL address, or adds the sixth TNL address to the F1-U connection of the migrated IAB node;

[0844] The fifth TNL address is the TNL address of the DU that can be routed to the first Donor device, and the sixth TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0845] 59. The method according to Appendix 58, wherein the method further comprises:

[0846] The first Donor device uses the first TNL address to send a second message to the migrated IAB node through the first F1-C connection. The second message includes a sixth TNL address for the F1-U connection of the migrated IAB node and / or a BAP route identifier and a backhaul RLC channel identifier for the F1-U connection of the migrated IAB node.

[0847] 60. The method according to Appendix 57a, wherein the method further comprises:

[0848] The first Donor device receives a second RRC reconfiguration message from the second Donor device for the UE that is migrating IAB node services;

[0849] The first Donor device uses the second TNL address to send the second RRC reconfiguration message to the migration IAB node through the first F1-C connection, so that the migration IAB node forwards the second RRC reconfiguration message to the UE it serves.

[0850] 61. The method according to Appendix 57a, wherein, in the case of the migration IAB node switching from the first Donor device to the second Donor device, before updating the first TNL address of the first F1-C connection of the migration IAB node to the second TNL address, the method further comprises:

[0851] The first Donor device receives a second RRC reconfiguration message from the second Donor device for the UE that is migrating IAB node services;

[0852] The second RRC reconfiguration message is sent to the migration IAB node via the first F1-C connection using the first TNL address, so that the migration IAB node forwards the second RRC reconfiguration message to the UE it serves.

[0853] 62. A group migration method, the method being applied to a first Donor device, migrating IAB nodes from the first Donor device to a second Donor device, wherein the method comprises:

[0854] The first Donor device sends a third TNL address to the second Donor device for establishing a second F1-C connection for the migrated IAB node;

[0855] Wherein, the second F1-C connection is the F1 connection between the DU of the IAB node and the CU of the second Donor device, and the third TNL address is the TNL address that can be routed to the DU of the first Donor device.

[0856] 63. The method according to Appendix 62, wherein migrating the IAB node from the first Donor device to the second Donor device means one of the following:

[0857] The migration IAB node is switched from the first Donor device to the second Donor device;

[0858] The migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device.

[0859] 64. The method according to Appendix 62, wherein the method further comprises:

[0860] The first Donor device receives the second TNL address sent by the second Donor for the first F1-C connection of the migrated IAB node, and adds the second TNL address to the first F1-C connection of the migrated IAB node.

[0861] Wherein, the second TNL address is the TNL address of the DU that can be routed to the second Donor device, and the first F1-C connection is the F1 connection between the DU of the IAB node and the CU of the first Donor device.

[0862] 65. The method according to Appendix 64, wherein the method further comprises:

[0863] The first Donor device receives the sixth TNL address of the F1-U connection of the migrated IAB node sent by the second Donor device;

[0864] The first Donor device updates the fifth TNL address of the F1-U connection of the migrated IAB node to the sixth TNL address or adds the sixth TNL address to the F1-U connection of the migrated IAB node;

[0865] Wherein, the fifth TNL address is the TNL address of the DU that can be routed to the second Donor device, and the sixth TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0866] 66. The method according to Appendix 62, wherein the method further comprises:

[0867] The first Donor device sends a third RRC reconfiguration message to the migration IAB node, wherein the third RRC reconfiguration message contains the third TNL address, so that the migration IAB node establishes a second F1-C connection with the CU of the second Donor device.

[0868] 67. The method according to Appendix 66, wherein the method further comprises:

[0869] The first Donor device receives a second RRC reconfiguration message from the second Donor device for the UE that is migrating IAB node services;

[0870] The first Donor device uses a first TNL address or a second TNL address to send the second RRC reconfiguration message to the migration IAB node via the first F1-C connection, so that the migration IAB node forwards the second RRC reconfiguration message to the UE it serves.

[0871] Wherein, the first TNL address is the TNL address of the DU that can be routed to the first Donor device, and the second TNL address is the TNL address of the DU that can be routed to the second Donor device.

[0872] 68. The method according to Appendix 66, wherein the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the method further comprising:

[0873] The first Donor device sends a second message to the migration IAB node via the first F1-C connection using either the first TNL address or the second TNL address, the second message containing at least one of the following:

[0874] The sixth TNL address used for F1-U connection;

[0875] BAP route identifier and backhaul RLC channel identifier used for F1-U connection.

[0876] 69. A donor device comprising a memory and a processor, the memory storing a computer program, wherein the processor is configured to execute the computer program to implement the method as described in any one of Appendices 1 to 31 and 57 to 68.

[0877] 70. An IAB node including a memory and a processor, the memory storing a computer program, wherein the processor is configured to execute the computer program to implement the method as described in any one of Appendices 32 to 56.

[0878] 71. A communication system comprising a Donor device, an IAB node, and a terminal device, wherein the Donor device is configured to perform the method described in any one of appendices 1 to 31 and 57 to 68, and the IAB node is configured to perform the method described in any one of appendices 32 to 56.

Claims

1. A group migration device, configured in a second Donor device, wherein, The device includes: When the IAB node moves from the first Donor to the second Donor device, the processing unit performs at least one of the following processes: The IAB node updates the first TNL address of the first F1-C connection to the second TNL address; The IAB node updates the third TNL address of the second F1-C connection to the fourth TNL address; Configure the IAB node with a fourth TNL address for establishing the second F1-C connection; Add a second TNL address to the IAB node for the first F1-C connection; Configure the IAB node with a third TNL address for establishing the second F1-C connection; Add a fourth TNL address to the IAB node for the second F1-C connection; Wherein, the first F1-C connection is the F1 connection between the DU of the IAB node and the CU of the first Donor device, the second F1-C connection is the F1 connection between the DU of the IAB node and the CU of the second Donor device, the first TNL address and the third TNL address are TNL addresses that can be routed to the DU of the first Donor device, and the second TNL address and the fourth TNL address are TNL addresses that can be routed to the DU of the second Donor device; The movement of the IAB node from the first Donor device to the second Donor device refers to one of the following situations: When the backhaul link of the IAB node under the first Donor device fails, the connection is re-established to the second Donor device. The IAB node switches from the first Donor device to the second Donor device; The IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device; Wherein, when the IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the IAB node receives a first RRC reconfiguration message; The first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection. The IAB node adds the second TNL address to the first F1-C connection.

2. The apparatus according to claim 1, wherein, When the backhaul link of the IAB node under the first Donor device fails, the processing unit performs the following processing: The IAB node updates the first TNL address of the first F1-C connection to the second TNL address; and Configure the IAB node with a fourth TNL address for establishing the second F1-C connection.

3. The apparatus according to claim 1, wherein, After the IAB node connection is re-established to the second Donor device, the processing unit sends a first RRC reconfiguration message to the IAB node. The first RRC reconfiguration message contains a second TNL address for the first F1-C connection, or the first RRC reconfiguration message contains a second TNL address for the first F1-C connection and a fourth TNL address for the second F1-C connection.

4. The apparatus according to claim 3, wherein, After the second Donor device establishes the second F1-C connection with the IAB node, the processing unit uses the fourth TNL address on the CU side of the second Donor device to send a first message to the DU of the IAB node through the second F1-C connection, so that the IAB node can establish a second context for the UE it serves. The first message contains a first context identifier of the UE, so that the IAB node can obtain the first context of the UE based on the first context identifier and reuse the first context to establish the second context.

5. A group migration apparatus, the apparatus being configured at a migration IAB node, the migration IAB node moving from a first Donor device to a second Donor device, wherein, The device includes: The receiving unit receives a first message from the first Donor device, the first message including at least one of the following: A second TNL address is used for the first F1-C connection to update the first TNL address of the first F1-C connection to the second TNL address, or to add the second TNL address to the first F1-C connection. The fourth TNL address is used for the second F1-C connection to update the third TNL address of the second F1-C connection to the fourth TNL address, or to establish the second F1-C connection with the CU of the second Donor device using the fourth TNL address, or to add the fourth TNL address to the second F1-C connection; The third TNL address is used for the second F1-C connection, to add the third TNL address to the second F1-C connection, or to use the third TNL address to establish the second F1-C connection with the CU of the second Donor device; Wherein, the first F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, the second F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the second Donor device, the first TNL address and the third TNL address are TNL addresses that can be routed to the first Donor device, and the second TNL address and the fourth TNL address are TNL addresses that can be routed to the second Donor device; The device further includes: a first establishment unit and a second establishment unit. The first establishing unit establishes a second F1-C connection with the second Donor device, and the receiving unit receives a second message sent by the CU of the second Donor device through the second F1-C connection using the fourth TNL address; the second establishing unit establishes a second context for the UE it serves based on the second message. The second message contains the first context identifier of the UE, and the migration IAB node obtains the first context of the UE based on the first context identifier and reuses the first context to establish the second context.

6. The apparatus according to claim 5, wherein, The migration of the IAB node from the first Donor device to the second Donor device refers to one of the following situations: When the backhaul link of the migrated IAB node under the first Donor device fails due to a wireless link failure, the connection is re-established to the second Donor device. The migration IAB node is switched from the first Donor device to the second Donor device; The migrated IAB node maintains its connection with the first Donor device and adds an interface connection with the second Donor device.

7. The apparatus according to claim 6, wherein, The device also includes a processing unit. After the migration IAB node connection is re-established to the second Donor device, the receiving unit receives the first message; The first message contains a second TNL address for the first F1-C connection, and the processing unit updates the first TNL address of the first F1-C connection to the second TNL address; Alternatively, the first message may include a second TNL address for the first F1-C connection and a fourth TNL address for the second F1-C connection. The processing unit updates the first TNL address of the first F1-C connection to the second TNL address and uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

8. The apparatus according to claim 7, wherein, The first message also includes at least one of the following: The BAP address assigned to the migrated IAB node; The backhaul RLC channel configuration for the migrated IAB node, and the default BAP route identifier and default backhaul RLC channel identifier for F1-C and non-F1 traffic; The migration IAB node is used to update the fifth TNL address of its F1-U connection to the sixth TNL address; BAP routing identifier and backhaul RLC channel identifier used for F1-U connection The fifth TNL address is a TNL address that can be routed to the DU of the first Donor device, and the sixth TNL address is a TNL address that can be routed to the DU of the second Donor device.

9. The apparatus according to claim 6, wherein, The device also includes a processing unit. When the migration IAB node switches from the first Donor device to the second Donor device, the receiving unit receives the first message; The first message includes a switching command and a fourth TNL address for the second F1-C connection. The first establishment unit uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device. Alternatively, the first message may contain a switching command and a second TNL address for the first F1-C connection, and the processing unit may update the first TNL address of the first F1-C connection to the second TNL address.

10. The apparatus according to claim 5, wherein, The device also includes a transmitting unit. The receiving unit receives an RRC reconfiguration message for the UE migrating IAB service, forwarded by the first Donor device using the second TNL address or using the first TNL address through the first F1-C connection, and the sending unit sends the RRC reconfiguration message to the UE it serves. The receiving unit receives an RRC reconfiguration complete message sent by the UE it serves, and the sending unit uses the fourth TNL address to send the RRC reconfiguration complete message to the second Donor device through the second F1-C connection.

11. The apparatus according to claim 7, wherein, The device also includes a processing unit. When the migration IAB node switches from the first Donor device to the second Donor device, the receiving unit receives the first message, which includes a switching command and a fourth TNL address for the second F1-C connection; the processing unit updates the third TNL address of the second F1-C connection to the fourth TNL address.

12. The apparatus according to claim 5, wherein, The device also includes a transmitting unit. The receiving unit receives an RRC reconfiguration message for the UE serving the migrated IAB node, forwarded by the first Donor device using the first TNL address through the first F1-C connection; the sending unit sends the RRC reconfiguration message to the UE it serves. The receiving unit receives the RRC reconfiguration complete message sent by the UE that is migrating the IAB node service, and the sending unit sends the RRC reconfiguration complete message to the second Donor device through the second F1-C connection using the third TNL address or the fourth TNL address.

13. The apparatus according to claim 7, wherein, While the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the receiving unit receives the first message; The first message includes secondary cell group (SCG) configuration information and a fourth TNL address or a third TNL address for the second F1-C connection. The first establishment unit uses the fourth TNL address or the third TNL address to establish the second F1-C connection with the CU of the second Donor device. Alternatively, the first message may include secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection, and the device may further include a processing unit that adds the second TNL address to the first F1-C.

14. The apparatus according to claim 13, wherein, If the first message does not contain the fourth TNL address used for the second F1-C connection, the processing unit adds an air interface connection to the second Donor device. The receiving unit receives a third message sent by the second Donor device, wherein the third message contains a fourth TNL address for the second F1-C connection; The first establishment unit uses the fourth TNL address to establish the second F1-C connection with the CU of the second Donor device.

15. The apparatus according to claim 7, wherein, While the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the receiving unit receives the first message; The first message includes secondary cell group (SCG) configuration information and a fourth TNL address for the second F1-C connection. The device also includes a processing unit that adds the fourth TNL address to the second F1-C connection. Alternatively, the first message may include secondary cell group (SCG) configuration information, a fourth TNL address for the second F1-C connection, and a second TNL address for the first F1-C connection. The device may also include a processing unit that adds the fourth TNL address to the second F1-C connection and adds the second TNL address to the first F1-C connection.

16. A group migration apparatus, configured in a first Donor device, for migrating IAB nodes from the first Donor device to a second Donor device, wherein, The device includes: The receiving unit receives the second TNL address of the first F1-C connection of the migrated IAB node sent by the second Donor device; The processing unit updates the first TNL address of the first F1-C connection of the migrated IAB node to the second TNL address, or adds the second TNL address to the first F1-C connection of the migrated IAB node; Wherein, the first F1-C connection is the F1 connection between the DU of the migrated IAB node and the CU of the first Donor device, the first TNL address is the TNL address of the DU that can be routed to the first Donor device, and the second TNL address is the TNL address of the DU that can be routed to the second Donor device. The migration of the IAB node from the first Donor device to the second Donor device refers to one of the following: When the backhaul link of the migrated IAB node fails under the first Donor device, the connection is re-established to the second Donor device. The migration IAB node is switched from the first Donor device to the second Donor device; The migrated IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device; Wherein, when the migrating IAB node maintains its connection with the first Donor device and adds an air interface connection with the second Donor device, the migrating IAB node receives a first RRC reconfiguration message; The first RRC reconfiguration message includes secondary cell group (SCG) configuration information and a second TNL address for the first F1-C connection. The migration IAB node adds the second TNL address to the first F1-C connection.

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