IAB node device, IAB donor device, and topology regression method

Abstract

In the embodiment of the present application, an IAB node device, an IAB donor device and a topology regression method are provided, in which the transmission path of an uplink service of an IAB node transitions from a first donor centralized unit to a second donor centralized unit, and then transitions from the second donor centralized unit to the first donor centralized unit, the method includes: an IAB node or a child node receives a path transition setting of uplink data sent by a network device; and an IAB node or a child node applies the path transition setting, and an IAB-DU of the IAB node maintains an F1 connection with a first donor-CU.

Description

Technical Field

[0001] The present invention relates to the technical field of communications.

Background Art

[0002] The deployment of future seamless cellular networks requires the deployment of very flexible and ultra-high density new radio (NR) cells. Ultra-high density networks are one of the goals of 5G, and the deployment of NR networks that do not require wired backhaul is very important for realizing the ultra-high density networks of 5G. Since the coverage of cells is reduced by 5G millimeter waves, wireless cell self-backhaul systems require multi-hop to meet the deployment needs. Due to the high bandwidth, large-scale multiple-input multiple-output (MIMO) and beam systems of 5G, compared with LTE, 5G makes it easier to develop wireless cell self-backhaul systems for ultra-high density NR cells. To develop such a multi-hop system with wireless cell self-backhaul, 3GPP (registered trademark) has started the research and standardization of the IAB (Integrated access and backhaul) project in Rel-16.

[0003] FIG. 1 is a diagram showing an IAB system. As shown in FIG. 1, in the IAB system, access and backhaul perform wireless transmission by adopting the NR Uu air interface. The relay node supports the functions of access and backhaul simultaneously. The relay node multiplexes the access link and the backhaul link in the time domain, frequency domain or spatial domain, and the access link and the backhaul link can use the same or different frequency bands.

[0004] In the IAB network architecture, a relay node refers to an IAB-node, which simultaneously supports access and backhaul functions. The last hop access node on the network side is called an IAB-donor, which supports gNB functionality and also supports access to the IAB-node. All UE data can be backhauled to the IAB-donor via an IAB-node, either single-hop or multi-hop.

[0005] The functionality of an IAB-node is divided into two parts: one part is the gNB-DU function, called the IAB-DU (Distributed Unit), and the other part is the UE function, called the IAB-MT (Mobile Terminal). The IAB-DU implements the functionality of network-side devices, is connected to downstream child IAB-nodes (or simply referred to as child nodes), provides NR air interface access to the UE and downstream child IAB-nodes, and establishes an F1 connection with the IAB donor-CU (Donor Central Unit). The IAB-MT implements the functionality of some terminal devices, is connected to upstream parent IAB-nodes (or simply referred to as parent nodes) or IAB donor-DUs, and includes the functionality of the physical layer, layer 2, RRC (Radio Resource Control), and NAS (Non-Access Stratum) layers, and is indirectly connected to the IAB Donor-CU and the Core Network (CN).

[0006] In an IAB system, an IAB node can access the network via SA (Standalone) mode or EN-DC (E-UTRA-NRDualConnectivity) mode. Figure 2 shows the IAB architecture in SA mode. Figure 3 shows the IAB architecture in EN-DC mode.

[0007] Figure 4 shows a single IAB node, a parent IAB node, and a child IAB node. As shown in Figure 4, 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 shows the F1 user plane (F1-U) protocol stack between the IAB-DU and the IAB donor-CU. Figure 6 shows the F1 control plane (F1-C) protocol stack between the IAB-DU and the IAB donor-CU. As shown in Figures 5 and 6, F1-U and F1-C are established on top of the transmission (IP) layer between the IAB-DU and the IAB donor-CU, with two-hop wireless backhaul and one-hop wired backhaul shown in Figures 5 and 6.

[0009] In a backhaul link, the transmission (IP) layer is carried to the backhaul adaptive protocol (BAP) sublayer, the BAP entity in the IAB-node implements the routing functionality of the IAB system, and the IAB donor-CU provides the routing table. BAP PDUs (Protocol Data Units) are transmitted over the RLC (Radio Link Control) channels of the backhaul link, and multiple RLC channels of the backhaul link may be configured by the IAB-donor to carry services (traffic) with different priorities and QoS (Quality of Service), with the BAP entity mapping the BAP PDUs to different backhaul RLC channels.

[0010] The above-mentioned introduction of background art is intended to clearly and completely explain the proposed technical aspects of the present invention and to facilitate understanding by those skilled in the art. These technical aspects, as described in the background art of the present invention, should not be construed as being well-known to those skilled in the art. [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] The inventors discovered the following: After a migrating node migrates from the network topology domain of the source donor-CU to the network topology domain of the target donor-CU, it may migrate back from the target donor-CU's network topology domain to the source donor-CU's network topology domain, which may be called topology revoking. Because the migrating node may change the donor-DU after topology revoking, the uplink data from the migrating node may not be able to be sent to the donor-CU. Furthermore, if the donor-DU after topology revoking has an IP address filtering function, it may drop uplink data containing IP addresses assigned by the donor-DU before topology revoking, which may result in relatively long transmission delays and service interruptions.

[0012] To solve at least one of the above-mentioned problems, embodiments of this application provide an IAB node device, an IAB donor device, and a topology regression method. [Means for solving the problem]

[0013] According to one aspect of the embodiment of this application, a topology regression method is provided in which the transmission path of an uplink service of an IAB node is transitioned from a first donor centrifuge unit (donor-CU) to a second donor centrifuge unit, and then from the second donor centrifuge unit back to the first donor centrifuge unit, and the method is as follows: The IAB node or child node receives the path transition settings for the uplink data transmitted by the network device; and This includes the application of the path transition settings by the IAB node or child node, Of these, the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU.

[0014] According to another aspect of the embodiment of this application, an IAB node device is provided, wherein the transmission path of its uplink service is transferred from a first donor central unit to a second donor central unit, and then transferred from the second donor central unit back to the first donor central unit, and the device, A receiving unit that receives path transition settings for uplink data transmitted by a network device; and Includes a processing unit that applies the aforementioned path transition settings, Of these, the IAB-DU of the IAB node maintains an F1 connection with the first donor central unit.

[0015] According to another aspect of the embodiments of this application, a topology regression method is provided in which the transmission path of an uplink service of an IAB node is transitioned from a first donor centrifuge (donor-CU) to a second donor centrifuge, and then from the second donor centrifuge back to the first donor centrifuge, and the method is as follows: The first donor-CU receives a topology regression request transmitted by the second donor-CU; and The first donor-CU transmits the path transition settings for the uplink data, Of these, the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU.

[0016] According to another aspect of the embodiment of this application, an IAB donor device is provided, wherein the transmission path for the uplink service of an IAB node is transferred from a first donor central unit to a second donor central unit, and then transferred from the second donor central unit back to the first donor central unit, and the device is, A receiving unit that receives topology regression requests transmitted by the second donor centralization unit; and Includes a transmission unit that transmits path transition settings for uplink data, Of these, the IAB-DU of the IAB node maintains an F1 connection with the first donor central unit.

[0017] According to another aspect of the embodiments of this application, an IAB system is provided which includes an IAB donor device and an IAB node device, After the transmission path for the uplink service of the IAB node device is transferred from the first donor central unit to the second donor central unit, it is then transferred from the second donor central unit to the first donor central unit. Among them, the IAB node device receives the path transition settings for the uplink data transmitted by the network device; and applies the path transition settings. Of these, the IAB-DU of the IAB node maintains an F1 connection with the first donor central unit. [Effects of the Invention]

[0018] The advantageous effects of the embodiments of the present invention are at least as follows: an IAB node or child node receives path transition settings for uplink data transmitted by a network device; and an IAB node or child node applies the path transition settings, of which the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU. This reduces or avoids the problem of uplink data being dropped, reduces transmission delay, and reduces service (traffic) interruption time.

[0019] Specific embodiments of the present invention will be disclosed in detail by referring to the description and drawings below, and will show embodiments that can adopt the principles of the present invention. However, the embodiments of the present invention are not limited to these in scope. Embodiments of the present invention may include various changes, modifications and substitutions within the scope of the attached claims.

[0020] Furthermore, features described and / or shown in one embodiment may be used in the same or similar manner in one or more other embodiments, combined with or substituting features in other embodiments.

[0021] Note that terms such as "comprising / including" when used in this specification refer to the presence of features, elements, steps, or assemblies, but also refer to the fact that the presence or addition of one or more other features, elements, steps, or assemblies is not excluded.

Brief Description of Drawings

[0022] The elements and features described in one drawing or one embodiment of the present invention can be combined with the elements and features shown in one or more other drawings or embodiments. Also, in the drawings, similar reference numerals indicate corresponding parts in several drawings and are also used to indicate corresponding parts used in multiple embodiments.

[0023] The included drawings are used to provide a further understanding of the embodiments of the present invention. These drawings form a part of this specification, illustrate the embodiments of the present invention, and are used to explain the principles of the present invention together with the written description. Also, as is clear, the drawings described below are only for showing some embodiments of the present invention, and those skilled in the art can also obtain other drawings based on these drawings without creative labor. [Figure 1] It is a diagram showing an IAB system. [Figure 2] It is a diagram showing the IAB architecture in SA mode. [Figure 3] It is a diagram showing the IAB architecture in EN-DC mode. [Figure 4] It is a diagram showing a parent IAB-node and a child IAB-node. [Figure 5] It is a diagram showing the F1-U protocol stack of an IAB system. [Figure 6] It is a diagram showing the F1-C protocol stack of an IAB system. [Figure 7] It is a diagram showing the routing of an IAB system. [Figure 8] It is a diagram showing network topology adaptation. [Figure 9]This figure shows topology regression in an embodiment of the present application. [Figure 10] This is another figure illustrating topology regression in the embodiment of this application. [Figure 11] This figure shows a topology regression method in an embodiment of the present application. [Figure 12] This figure shows an example of topology regression in an embodiment of the present application. [Figure 13] This figure shows another example of topology regression in the embodiments of this application. [Figure 14] This is a flowchart of the signaling of topology regression in the embodiment of this application. [Figure 15] This is a flowchart of another signaling mechanism for topology regression in the embodiment of this application. [Figure 16] This figure shows an IAB node device in an embodiment of the present application. [Figure 17] This figure shows an IAB donor device in an embodiment of the present application. [Figure 18] This figure shows the IAB apparatus in an embodiment of the present application. [Modes for carrying out the invention]

[0024] The aforementioned and other features of the present invention will become clear by referring to the attached drawings and the following description. While the specification and drawings disclose specific embodiments of the present invention, they represent only a limited number of embodiments that may employ the original principles of the invention. It should be understood that the present invention is not limited to the embodiments described, and that it also includes all modifications, variations, and substitutions within the scope of the attached claims.

[0025] In embodiments of the present invention, the terms "communication network" or "wireless communication network" may refer to a network conforming to any communication standard such as, for example, New Wireless (NR), LTE (Long Term Evolution), LTE-A (LTE-Advanced), WCDMA (registered trademark) (Wideband Code Division Multiple Access), HSPA (High-Speed ​​Packet Access), etc.

[0026] Furthermore, communication between devices in a communication system may be carried out according to any stage of communication protocol, and may include, but is not limited to, the following communication protocols: namely, 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G, 5G, New Radio (NR), and / or other conventional or future-developed communication protocols.

[0027] In embodiments of the present invention, the term "network device" refers, for example, to a device in a communication system that connects terminal devices to a communication network and provides services to said terminal devices. Network devices may include, but are not limited to, the following: IAB-node, base station (BS), access point (AP), transmission / reception point (TRP), broadcast transmitter, mobile management entity (MME), network gateway, server, radio network controller (RNC), base station controller (BSC), etc.

[0028] Among these, base stations may include, but are not limited to, Node B (NodeB or NB), Evolutionary Node B (eNodeB or eNB), 5G base stations (gNB), and may also include RRH (Remote Radio Head), RRU (Remote Radio Unit), relay, or low-power nodes (e.g., femto, pico). Furthermore, the term "base station" may include some or all of these functions, and each base station can provide communication coverage to a specific geographic area. The term "cell" may refer to a base station and / or the area it covers, depending on the context of the term.

[0029] In embodiments of the present invention, the terms "User Equipment" (UE) or "Terminal Equipment" (TE) refer to, for example, a device that accesses a communication network via a network device and receives services from the network. User equipment may be fixed or mobile, and may also be referred to as a mobile station (MS), terminal, subscriber station (SS), access terminal (AT), station, etc.

[0030] Among these, user devices may include, but are not limited to, the following: cellular phones, PDAs (Personal Digital Assistants), wireless modems, wireless communication devices, mobile devices, machine-type communication devices, laptop computers, cordless telephones, smartphones, smartwatches, digital cameras, etc.

[0031] Furthermore, in scenarios such as IoT (Internet of Things), the user device may also be a monitoring or measurement device or equipment, and may include, but is not limited to, the following: machine-type communication (MTC) terminals, in-vehicle communication terminals, D2D (device to device) terminals, M2M (machine to machine) terminals, etc.

[0032] The routing functionality of the IAB system is implemented by the BAP layer, and each IAB-node node stores routing configurations (BH routing configuration) and RLC channel mapping configurations (BH RLC Channel Mapping Configuration). The BAP entity performs routing based on the routing configuration, RLC channel mapping configuration, and routing ID in the BAP layer data packet header. The routing ID includes the destination BAP address and route indicator.

[0033] Routing configurations include the mapping relationship between the Routing ID and the BAP address of the next-hop node. RLC channel mapping configurations include the mapping relationship between the BAP address of the prior-hop node, the entry link RLC channel ID, and the BAP address of the next-hop node and the exit link RLC channel ID.

[0034] Figure 7 shows the IAB system routing. As shown in Figure 7, for each data packet, the routing ID in the data packet header allows us to find the BAP address of the next hop node from the routing configuration. The BAP address and ingress link RLC channel ID of the preceding hop node (the node of the previous hop) are all known. In this way, after determining the BAP address of the next hop node, the RLC channel mapping configuration allows us to find the exit link RLC channel ID based on the preceding hop node's BAP address + ingress link RLC channel ID + next hop node's BAP address.

[0035] The IAB-donor DU stores routing configurations (BH routing configuration) and downlink RLC channel mapping configurations (Downlink Traffic to BH RLC Channel Mapping Configuration). The IAB-donor DU performs routing based on the routing configuration, RLC channel mapping configuration, and the Routing ID in the BAP layer data packet header. The routing configuration includes the mapping relationship between the Routing ID and the address of the next-hop node. The downlink RLC channel mapping configuration includes the mapping relationship between the target IP address, DSCP (Differentiated Services Code Point), and the address of the next-hop node and the exit link RLC channel ID.

[0036] For each downlink data packet reaching the IAB-donor DU, the IAB-donor DU can find the address of the next-hop node from the routing configuration based on the Routing ID in the data packet header. After determining the address of the next-hop node in this way, the IAB-donor DU can find the exit link RLC channel ID from the downlink RLC channel mapping configuration based on the IP address and DSCP of the data packet.

[0037] The above provides an illustrative explanation of routing in an IAB system; the following describes updating the network topology of an IAB system. Rel-16 NR already standardizes the topology adaptation process when an IAB node moves under the same donor CU.

[0038] Figure 8 shows the intra-CU topology adaptation. When an IAB-node changes its parent node (from IAB-node 1 to IAB-node 2), the donor-CU uses an RRC reconfiguration message to set path transition-related settings for the IAB-node, causing the IAB-node to perform the F1 transmission path transition.

[0039] The path transition-related settings include updates to the default backhaul RLC channel (default BH RLC channel) for uplink F1-C, F1-U, and non-F1 data, updates to the default BAP routing ID, and updates to the IP address to route to the Donor-DU. When an IAB-node accesses a new parent node, it begins applying the above path transition-related settings, and the same method is used to configure the path transition-related settings for the IAB-node's child nodes.

[0040] 3GPP R17 supports topology adaptation when an IAB-node moves under a different donor-CU, allowing the migrating node to switch from a parent node served by the source donor-CU (which may also be called the F1-terminating CU or first donor-CU) to a parent node served by the target donor-CU (which may also be called the non-F1-terminating CU or second donor-CU).

[0041] After the transition node is switched from an F1-terminating CU to a non-F1-terminating CU, only the RRC connection of the IAB-MT is switched to a non-F1-terminating CU, the F1 interface still belongs to the F1-terminating CU, and the RRC connections of the child nodes and UEs it serves still belong to the F1-terminating CU. At this point, the transition node may be referred to as a boundary node.

[0042] The routing IDs for F1 and non-F1 data at the boundary node and for F1 and non-F1 data at child nodes may remain unchanged, but the boundary node must replace the original routing ID of the uplink traffic with the target routing ID. Of these, the original routing ID belongs to the topology domain of the F1-terminating CU, and its destination BAP address is the original donor-DU under the F1-terminating CU, while the replaced routing ID belongs to the topology domain of the non-F1-terminating CU, and its destination BAP address is the target donor-DU under the non-F1-terminating CU.

[0043] Furthermore, boundary nodes may switch from non-F1-terminating CUs to F1-terminating CUs, i.e., perform topology regression. When a boundary node switches to an F1-terminating CU, it does not need to replace the original routing ID with the routing ID of the non-F1-terminating CU domain, but it does need to have routing settings for the original routing ID and BH RLC channel mapping settings from the boundary node to the parent node on the F1-terminating CU side.

[0044] The inventors discovered the following: When a boundary node is switched to an F1-terminating CU, if the donor-DU of the F1-terminating CU has an IP address filtering function, it becomes impossible to send uplink data carrying the IP address assigned by the donor-DU on the non-F1-terminating CU side to the donor-CU, which may result in relatively long transmission delays and service interruptions.

[0045] Figure 9 shows the topology regression in an embodiment of this application. As shown in Figure 9, IAB node 3 transitions from donor-DU 1 of the source donor-CU to donor-DU 2 of the target donor-CU, and then regresses from donor-DU 2 of the target donor-CU to donor-DU 1 of the source donor-CU. If donor-DU 1 of the source donor-CU has an IP address filtering function, uplink data with an IP address assigned by donor-CU 2 on the target donor-CU side cannot be sent to the source donor-CU because it may be dropped by donor-DU 2 on the source donor-CU side. Since the dropped uplink data can be retransmitted by the UE, it may result in relatively long transmission delays and service interruptions.

[0046] Furthermore, the inventors discovered the following: When a boundary node is switched to an F1-terminating CU, if the donor-DU after the boundary node switch is different from the original donor-DU, the uplink data generated by the transitioning node and child nodes based on the original routing ID cannot be sent to the F1-terminating CU, which can result in relatively long transmission delays and service interruptions.

[0047] Figure 10 is another diagram illustrating topology regression in an embodiment of this application. As shown in Figure 10, IAB node 3 is migrated from donor-DU 1 of the source donor-CU to donor-DU 2 of the target donor-CU, and then regresses from donor-DU 2 of the target donor-CU to donor-DU 3 of the source donor-CU. Because the switched (regressed) donor-DU 3 is different from the original donor-DU 1, the uplink data generated by the transition node and child nodes based on the original routing ID cannot be sent to the source donor-CU. This is because the uplink data generated based on the original routing ID carries the BAP address of donor-DU 1, which is different from the BAP address of donor-DU 3, and therefore this uplink data may be dropped by the target donor-DU 3. Since the dropped uplink data can be retransmitted by the UE, this may result in relatively long transmission delays and service interruptions.

[0048] In view of at least one of the above-mentioned problems or similar problems, an IAB node or child node in an embodiment of the present application receives a path transition setting for uplink data transmitted by a network device before the IAB-MT of the IAB node is switched from the second donor-CU to the first donor-CU or after it has been switched to the first donor-CU, and a detailed explanation follows. In an embodiment of the present application, unless otherwise specified, the transition node is an IAB node, and the IAB node device includes an IAB node or its child nodes.

[0049] <Example of the first side view> An embodiment of this application provides a topology regression method, which is described from the perspective of an IAB node or child node. In this embodiment, the transmission path for the uplink service of the IAB node is transitioned from a first donor centrifuge unit (donor-CU) to a second donor centrifuge unit, and then from the second donor centrifuge unit back to the first donor centrifuge unit.

[0050] Figure 11 shows a topology regression method in an embodiment of the present application. As shown in Figure 11, the method includes the following steps.

[0051] 1101: An IAB node or child node receives a path transition setting for uplink data transmitted by a network device; and 1102: An IAB node or child node applies the path transition setting, and of which, the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU.

[0052] Figure 11 above is provided to illustrate an embodiment of this application, but the application is not limited thereto. For example, the execution order between each operation (step) can be appropriately adjusted, or several other operations can be added or removed. Those skilled in the art can make appropriate modifications based on the above description, without being limited to the description in Figure 11.

[0053] The following describes the case where the transmission path for IAB node uplink services (including F1-C, F1-U, and non-F1 services (traffic)) is migrated from the first donor central unit (donor-CU) to the second donor central unit.

[0054] When an IAB node's uplink service transitions from an F1-terminating CU to a non-F1-terminating CU, the network device can configure the IAB node with a mapping relationship between the original routing ID and the target routing ID, i.e., BAP Header Rewriting Information (BAP Header Rewriting Information) between donor centralized units.

[0055] Subsequently, when the IAB node forwards the uplink data, it replaces the original routing ID with the target routing ID. Since the target routing ID belongs to the non-F1-terminating CU domain, the IAB node must make routing selections based on the routing information of the target routing ID and the target donor-CU's topology domain. Therefore, the network device can configure the IAB node with routing information where the next-hop node's BAP address belongs to the non-F1-terminating CU topology domain (in the routing information before path transition, the BAP address of the next-hop node of the egress link belongs to the F1-terminating CU topology domain).

[0056] Since the BAP address of the preceding hop node of the IAB node belongs to the F1-terminating CU topology domain, and the BAP address of the next hop node belongs to the non-F1-terminating CU topology domain, the network device can reconfigure the RLC channel mapping information at the IAB node (in the RLC channel mapping information before the path transition, the addresses of both the preceding hop node and the next hop node all belong to the F1-terminating CU topology domain).

[0057] The embodiments of this application will be further described below with respect to different scenarios in which the transmission path of the IAB node's uplink services (including F1-C, F1-U, and non-F1 services) is transitioned (regressed) from the second donor-CU to the first donor-CU. First, the handover scenario will be described as an example, in which the IAB node or child node receives the path transition settings for the uplink data transmitted by the network device before or after the IAB-MT of the IAB node is switched from the second donor-CU to the first donor-CU. In the handover scenario, it is necessary to transition the transmission path of all uplink services of the IAB node from the second donor-CU to the first donor-CU.

[0058] In some embodiments, the transmission path for the uplink service of an IAB node transitions from the first donor distributed unit (donor-DU) of the first donor-CU to the second donor-DU of the second donor-CU, and then from the second donor-DU of the second donor-CU to the first donor-DU of the first donor-CU.

[0059] In some embodiments, the path transition settings are sent from the first donor-CU to the IAB node or child node via an F1AP message or RRC message.

[0060] In some embodiments, for uplink services that need to switch to the first donor-CU, the path transition configuration includes the following: an increase (addition) in routing configuration to indicate the mapping relationship between the first routing sign and the BAP address of the next hop node of the IAB node; and an increase in the first RLC channel mapping configuration to indicate the mapping relationship between the BAP address of the preceding hop node of the IAB node, the ingress link radio link control (RLC) channel sign and the BAP address of the next hop node of the IAB node, and the egress link RLC channel sign, of which the first routing sign, the preceding hop node's BAP address and the next hop node's BAP address belong to the network topology domain of the first donor-CU, and the destination BAP address of the first routing sign is the BAP address of the first donor-DU.

[0061] For example, when a boundary node is switched from a non-F1-terminating CU to an F1-terminating CU, and the parent node after the switch still uses the original donor-DU, the network device only needs to configure the boundary node with routing information belonging to the F1-terminating CU topology domain for the original routing ID, as well as RLC channel mapping information from the boundary node to the parent node after the switch (the addresses of the preceding hop node and the next hop node all belong to the F1-terminating CU area).

[0062] In some embodiments, the IAB node or child node receives the path transition settings before the IAB-MT switches from the second donor-CU to the first donor-CU.

[0063] Furthermore, to avoid the loss of uplink data due to the lack of available routing or exit RLC channels after regression, the network device must configure routing information belonging to the F1-terminating CU topology domain for the original routing ID, and RLC channel mapping information from the boundary node to the parent node after regression, before the boundary node performs regression (the addresses of the preceding hop node and the next hop node all belong to the F1-terminating CU topology domain). Therefore, non-F1-terminating CUs can initiate topology regression before or during regression preparation so that these parameters can be applied after regression.

[0064] For the uplink service being migrated (regressed) to the first donor-CU, it is necessary to release the corresponding routing sign rewrite sign, routing information, and RLC channel mapping information. In some embodiments, the path transition configuration further includes, namely, the release of a donor-CU inter-routing sign rewrite configuration to indicate the mapping relationship between the first routing sign and the second routing sign; the release of a routing configuration to indicate the mapping relationship between the second routing sign and the BAP address of the next-hop node of the IAB node; or the release of a second RLC channel mapping configuration to indicate the mapping relationship between the address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next-hop node of the IAB node, and the outlet link RLC channel sign, wherein the first routing sign and the BAP address of the preceding hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the first routing sign is the BAP address of the first donor-DU, the second routing sign and the BAP address of the next-hop node of the IAB node belong to the network topology domain of the second donor-CU, and the destination BAP address of the second routing sign is the BAP address of the second donor-DU.

[0065] For example, the path transition setting may include one of the following: the release of the routing indicator rewrite setting, the release of the routing setting, and the release of the second RLC channel mapping setting; any two of these; or all three settings; however, this application is not limited thereto.

[0066] Figure 12 shows an example of topology regression in an embodiment of the present application. As shown in Figure 12, IAB node 3 (including IAB-MT 3 and IAB-DU 3) is a transition node, and the transmission path it serves is transitioned from donor-DU 1 of the source donor-CU to donor-DU 2 of the target donor-CU. After the switchover is complete, IAB-MT 3 of IAB node 3 is transitioned from donor-DU 2 of the target donor-CU to donor-DU 1 of the source donor-CU.

[0067] As shown by the solid line on the right side of Figure 12, the routing IDs for the uplink service of IAB node 3 and the uplink services of child nodes (e.g., IAB nodes 4 and 5 shown in Figure 12) can be maintained immutably, meaning that the routing ID with destination address dornor-DU 1 can still be used.

[0068] The above explains the case of routing IDs; the following explains the case of IP addresses.

[0069] In some embodiments, in order to transfer a service back to the first donor-CU, the IAB node or child node receives configuration information transmitted by the first donor-CU, and this configuration information is used to configure the replacement of the configuration information of the IP address anchored to the second donor-DU with the IP address anchored to the first donor-DU, of which the IP address is used for the IAB node or child node's F1 user plane data, F1 control plane data, or non-F1 data.

[0070] For example, if the first donor-DU has a source IP address filtering function, meaning it can drop uplink data containing IP addresses assigned by other donor-DUs, the migration node needs to change the IP addresses carried by the uplink service to the IP addresses assigned by the first donor-DU. Therefore, the donor-CU sets the IP addresses assigned by the target donor-DU on the migration node before the migration node performs the switchover.

[0071] In the embodiments of this application, “IP address anchored to IAB donor-DU” may also be understood as “IP address assigned by donor-DU” or “Transmission Network Layer (TNL) address(es) that is (are) routable via the IAB-donor-DU,” and these terms are interchangeable, and this application is not limited thereto.

[0072] The routing ID for services (including uplink and downlink services) can remain immutable in the transition node and child nodes, but the IP address anchored to the second donor-DU must be replaced with the IP address anchored to the first donor-DU. Also, since the IAB node and child nodes are IP addresses selected and used based on the address of the first donor-DU, the IP address configuration for services must be done for the BAP address of the first donor-DU, and involves increasing the IP address anchored to the first donor-DU and releasing the IP address anchored to the second donor-DU.

[0073] In some embodiments, the configuration information is IP address configuration information for the BAP address of the first donor-DU. For example, this configuration information is used to change the IP address anchored to the second donor-DU for the BAP address of the first donor-DU to the IP address anchored to the first donor-DU.

[0074] In some embodiments, the IAB node or child node receives configuration information before the IAB-MT switches from the second donor-CU to the first donor-CU.

[0075] In some embodiments, an IAB node or child node replaces the IP address anchored to the second donor-DU with the IP address anchored to the first donor-DU when the IAB-MT completes the switchover from the second donor-CU to the first donor-CU.

[0076] For example, upon completion of the switchover, the migration node must immediately apply the IP addresses assigned by the first donor-DU. Furthermore, the aforementioned "replace" could also be understood as "increasing the number of IP addresses anchored to the first donor-DU and releasing the IP addresses anchored to the second donor-DU."

[0077] In some embodiments, the configuration information of the IAB node is transmitted by the donor central unit via a switching command radio resource control (RRC) message or an RRC reset message. The configuration information of the child node is transmitted by the donor central unit via an RRC reset message.

[0078] For example, if the donor-DU under the F1-terminating CU has an IP address filtering function, in order to reduce uplink data drops, the network device needs to set the IP address assigned by the F1-terminating CU's donor-DU to the boundary node on the boundary node before the boundary node switches over. This allows the boundary node to immediately apply the IP address when the switchover is complete.

[0079] Furthermore, the network device must set the IP address assigned to the child node by the donor-DU under the F1-terminating CU to the child node before the boundary node switches over. This allows the child node to immediately apply the assigned IP address when the boundary node switches over.

[0080] Furthermore, for example, upon completion of the regression, the boundary node can send an instruction to the child node to cause the child node to apply the aforementioned IP address settings; or, before the switchover is complete, the parent node of the node can cache the aforementioned IP address set for the child node until the boundary node completes the regression, and then send it to the child node.

[0081] The above describes the case where the transmission path for the uplink service of the transition node is migrated to the original dornor-DU. Below, we will describe the case where the transmission path for the uplink service of the transition node is migrated (regressed) to another dornor-DU.

[0082] In some embodiments, the transmission path for the uplink service of the IAB node transitions from the first donor-DU of the first donor-CU to the second donor-DU of the second donor-CU, and then from the second donor-DU of the second donor-CU to the third donor-DU of the first donor-CU.

[0083] In some embodiments, for uplink services transitioned to the first donor-CU, the path transition settings include the following: an increase in donor-DU routing sign rewrite settings to indicate the mapping relationship between the first routing sign and the third routing sign; an increase in routing settings to indicate the mapping relationship between the third routing sign and the BAP address of the next-hop node of the IAB node; and an increase in first RLC channel mapping settings to indicate the mapping relationship between the BAP address of the preceding hop node of the IAB node, the ingress link RLC channel sign, and the BAP address of the next-hop node of the IAB node and the egress link RLC channel sign. Of these, the first routing sign, the third routing sign, the BAP address of the preceding hop node of the IAB node, and the BAP address of the next-hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the third routing sign is the BAP address of the third donor-DU, and the destination BAP address of the first routing sign is the BAP address of the first donor-DU.

[0084] In some embodiments, the IAB node or child node receives the path transition settings before the IAB-MT switches from the second donor-CU to the third donor-CU.

[0085] For the uplink service that migrates to and returns to the first donor-CU, it is necessary to release the corresponding routing sign rewrite sign, routing information, and RLC channel mapping information. In some embodiments, the path transition configuration further includes, namely, the release of a donor-CU inter-routing sign rewrite configuration to indicate the mapping relationship between the first routing sign and the second routing sign; the release of a routing configuration to indicate the mapping relationship between the second routing sign and the BAP address of the next-hop node of the IAB node; or the release of a second RLC channel mapping configuration to indicate the mapping relationship between the address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next-hop node of the IAB node, and the exit link RLC channel sign, wherein the first routing sign and the BAP address of the preceding hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the first routing sign is the BAP address of the first donor-DU, the second routing sign and the BAP address of the next-hop node of the IAB node belong to the network topology domain of the second donor-CU, and the destination BAP address of the second routing sign is the BAP address of the second donor-DU.

[0086] For example, the path transition setting may include one of the following: the release of the routing indicator rewrite setting, the release of the routing setting, and the release of the second RLC channel mapping setting; any two of these; or all three settings; however, this application is not limited thereto.

[0087] Figure 13 shows another example of topology regression in an embodiment of the present application. As shown in Figure 13, IAB node 3 (including IAB-MT 3 and IAB-DU 3) is a transition node, and the transmission path it serves is transitioned from donor-DU 1 of the source donor-CU to donor-DU 2 of the target donor-CU, and then transitions back from donor-DU 2 of the target donor-CU to donor-DU 3 of the source donor-CU.

[0088] After the IAB-MT 3 regression on IAB node 3 is complete, the routing IDs for the uplink service of IAB node 3 and the uplink service of its child nodes (e.g., IAB node 4, IAB node 5, etc., shown in Figure 13) can be kept unchanged, as shown by the solid line on the right.

[0089] In some embodiments, since the IAB node has already received the network device-transmitted mapping relationship information (inter-donor-DU rewriting information), the IAB node can rewrite the first routing indicator carried in the BAP header of the uplink data to the third routing indicator.

[0090] For example, as shown by the dotted line on the right side of Figure 13, IAB node 3 needs to replace the original routing IDs of the uplink service and the uplink service of the child nodes (e.g., IAB nodes 4 and 5 shown in Figure 13) with the target routing IDs. Of these, the destination BAP address of the original routing ID is donor-DU 1 of the source donor-CU, and the destination BAP address of the replaced routing ID is donor-DU 3 of the source donor-CU.

[0091] Furthermore, for example, after replacing the source routing ID with the target routing ID, routing selection and backhaul RLC channel selection can be performed based on the target routing ID, and the donor-CU updates the routing information and RLC channel mapping information on the migration node (because the original routing information does not include available routing for the target routing ID).

[0092] The transition node can apply inter-donor-DU rewriting information, new routing information, and RLC channel mapping information upon completion of the switchover or upon receiving the configuration. The donor-CU instructs the transition node to cache the aforementioned path transition settings in advance, and then applies the aforementioned path transition settings upon completion of the IAB-MT switchover.

[0093] The above explains the case of routing IDs; the following explains the case of IP addresses.

[0094] In some embodiments, in order to transfer and return a service to the first donor-CU, the IAB node or child node receives configuration information to configure it to replace the IP address anchored to the second donor-DU with the IP address anchored to the third donor-DU, of which the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node.

[0095] For example, if donor-DU 3 has an IP address filtering function, meaning it can drop uplink data containing IP addresses assigned by other donor-DUs, the transition node needs to change the IP addresses carried in the uplink F1-U data to the IP addresses assigned by donor-DU 3. Therefore, donor-CU sets the IP addresses assigned by donor-DU 3 for F1-U on the transition node before the transition node performs the switchover.

[0096] In the embodiments of this application, “IP address anchored to IAB donor-DU” may also be understood as “IP address assigned by donor-DU” or “Transmission Network Layer (TNL) address(es) that is (are) routable via the IAB-donor-DU,” and these terms are interchangeable, but this application is not limited thereto.

[0097] In some embodiments, the IAB node or child node receives the above configuration information before the IAB-MT switches from the second donor-CU to the first donor-CU.

[0098] The routing ID for services (including uplink and downlink services) can remain immutable on the migration node and child nodes, but IP addresses anchored to the second Donor-DU must be replaced with IP addresses anchored to the third Donor-DU. Also, since the IAB nodes and child nodes are IP addresses selected and used based on the address of the first Donor-DU, the IP address configuration for services must be done for the BAP address of the first Donor-DU, including the incrementing of IP addresses anchored to the third donor-DU and the release of IP addresses anchored to the second donor-DU.

[0099] In some embodiments, the configuration information is IP address configuration information for the BAP address of the first donor-DU. For example, this configuration information is used to change the IP address anchored to the second donor-DU for the BAP address of the first donor-DU to the IP address anchored to the third donor-DU.

[0100] In some embodiments, the IAB node or child node replaces the IP address anchored to the second donor-DU with the IP address anchored to the third donor-DU when the IAB-MT completes the switchover from the second donor-CU to the first donor-CU.

[0101] For example, the migration node must immediately apply the IP addresses assigned by donor-DU 3 upon completion of the switchover. Also, for example, the "replace" mentioned above could be further understood as "increasing the number of IP addresses anchored to the third donor-DU and releasing the IP addresses anchored to the second donor-DU."

[0102] In some embodiments, the configuration information of the IAB node is transmitted by the donor central unit via a switching command radio resource control (RRC) message or an RRC reset message. The configuration information of the child node is transmitted by the donor central unit via an RRC reset message.

[0103] The above explanation uses the handover scenario as an example; below, we will explain the re-establishment scenario and the dual connection scenario. Note that the same information as in the handover scenario described above will be omitted here.

[0104] In some embodiments, an IAB node or child node receives path transition settings for uplink data transmitted by the network device after the IAB-MT of the IAB node has re-established with the second donor-CU; and the IAB node or child node applies the path transition settings, of which the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU. In the re-establishment scenario, it is necessary to transition the transmission path of all services of the IAB node back from the second donor-CU to the first donor-CU.

[0105] In some embodiments, an IAB node or child node receives path transition settings for uplink data transmitted by a network device; and the IAB node or child node applies the path transition settings, wherein the IAB-MT of the IAB node establishes dual connections with the first donor-CU and the second donor-CU, and the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU. In dual connection scenarios, only the transmission path for some IAB nodes' services may be transitioned back from the second donor-CU to the first donor-CU.

[0106] The embodiments described above are for illustrative purposes to illustrate the embodiments of this application, but this application is not limited thereto, and appropriate modifications can be made based on the embodiments described above. For example, the embodiments described above may be used individually, or a combination of several of the embodiments described above may be used.

[0107] As can be seen from the above embodiment, the IAB node or child node receives the path transition settings for the uplink data transmitted by the network device; and the IAB node or child node applies the path transition settings, in which case the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU. This reduces or avoids the problem of uplink data being dropped, reduces transmission delay, and reduces service interruption time.

[0108] <Example of the second aspect> The embodiments of this application provide a topology regression method, which will be described from the donor concentration unit side. Note that descriptions identical to those in the first embodiment will be omitted here.

[0109] In some embodiments, the transmission path for the uplink service of an IAB node is migrated from a first donor centrifuge unit (donor-CU) to a second donor centrifuge unit, and then from the second donor centrifuge unit back to the first donor centrifuge unit. The first donor-CU receives a topology regression request sent by the second donor-CU; and the first donor-CU sends a path migration setting for the uplink data, in which case the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU.

[0110] In some embodiments, the transmission path for the uplink service of an IAB node is transitioned from the first donor distributed unit (donor-DU) of the first donor-CU to the second donor-DU of the second donor-CU, and then transitions back (regresses) from the second donor-DU of the second donor-CU to the first donor-DU of the first donor-CU.

[0111] In some embodiments, the transmission path for the uplink service of the IAB node transitions from the first donor-DU of the first donor-CU to the second donor-DU of the second donor-CU, and then transitions back (regresses) from the second donor-DU of the second donor-CU to the third donor-DU of the first donor-CU.

[0112] In some embodiments, the first donor-CU transmits the path transition settings to the IAB node or the child node via an F1AP message or RRC message.

[0113] In some embodiments, the topology regression request includes an IP address anchored to the second donor-DU for the BAP address of the first donor-DU, of which the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node.

[0114] In some embodiments, the first donor-CU transmits to the second donor-CU configuration information to configure the replacement of the IP address anchored to the second donor-DU with the IP address anchored to the first donor-DU, or configuration information to configure the replacement of the IP address anchored to the second donor-DU with the IP address anchored to the third donor-DU.

[0115] Below, we will begin by explaining using a handover scenario as an example.

[0116] In some embodiments, the first donor-CU transmits the uplink data path transition settings before or after the IAB-MT of the IAB node is switched from the second donor-CU to the first donor-CU.

[0117] In some embodiments, the second donor-CU sends a switching request to the first donor-CU for the IAB-MT to switch to the first donor-CU, and then sends a topology regression request to the first donor-CU.

[0118] Figure 14 is a flowchart of the signaling for topology regression in an embodiment of this application, illustrating an example where topology regression is performed after preparation for switching when an IAB node (boundary node) is switched from a non-F1-terminating CU to an F1-terminating CU.

[0119] - The boundary node sends a measurement report to the target donor-CU, triggering a switchover preparation that initiates the regression of the non-F1-terminating CU (target donor-CU) to the F1-terminating CU (source donor-CU).

[0120] - After the boundary node's regression is complete, the target donor-CU sends a release request for the UE context for the boundary node-MT to the source donor-CU.

[0121] - The target donor-CU sends a topology regression request Xn message to the source donor-CU (a UA (UE-associated message) for the boundary node, and using the boundary node's XnAP indicator). This includes a request to allocate an IP address for F1 or non-F1 services if it is a transition node, and a request to allocate an IP address for both F1 and non-F1 services if it is a child node.

[0122] - If the boundary node is switched back to the original donor-DU, configure the boundary node with routing information in the F1-terninated CU topology domain for the original routing ID, configure new RLC channel mapping information belonging to the F1-terminating CU topology, request the original donor-DU to assign IP addresses for the boundary node's F1 and non-F1 services, and request the original donor-DU to assign IP addresses for the child nodes' F1 and non-F1 services. If the boundary node is not switched back to the original donor-DU, configure the boundary node with inter-donor-DU rewriting information in the F1-terminating CU domain, configure the boundary node with routing information in the F1-terninating CU topology domain for the target routing ID after the switch, configure new RLC channel mapping information belonging to the F1-terminating CU topology, request the new donor-DU to assign IP addresses for the boundary node's F1 and non-F1 services, and request the new donor-DU to assign IP addresses for the child nodes' F1 and non-F1 services.

[0123] - The source donor-CU uses an F1AP message to send the aforementioned inter-donor-DU rewriting information, routing information, and RLC channel mapping information to the boundary node, and releases the following configuration: BAP Header Rewriting Information, routing information for the Non-F1-terminating CU area, and RLC channel mapping information where the address of the preceding hop node belongs to the F1-terminating CU topology and the address of the next hop node belongs to the non-F1-terminating CU topology.

[0124] - The source donor-CU sends an RRC reconfiguration message to the boundary node (including the IP addresses assigned by the new donor-DU or the original donor-DU under the F1-terninating-CU for F1 and non-F1 services).

[0125] - The source donor-CU sends an RRC reconfiguration message to the child node (including the IP address assigned by the new donor-DU or the original donor-DU under the F1-terninating-CU for F1 and non-F1 services).

[0126] - (Optional) The source donor-CU updates routing information and RLC channel mapping information for nodes along the original path.

[0127] - The boundary node will apply the configured IP address.

[0128] - The child node will use the configured IP address.

[0129] - The source donor-CU sends a topology regression response Xn message to the target donor-CU (a UA (UE-associated message) for the boundary node, and using the boundary node's XnAP indicator).

[0130] - The target donor-CU / source donor-CU will release the XnAP indicator for the boundary node.

[0131] The signaling process described above is for illustrative purposes only in illustrating the embodiments of this application, but is not limited thereto, and further references to related technologies can be found for more specific details of signaling.

[0132] In some embodiments, the second donor-CU includes a topology regression request in the switching request for switching the IAB-MT back to the first donor-CU.

[0133] In some embodiments, the configuration information is included in the RRC reconfiguration message, which is included in the switching request response message regarding the switching of the IAB-MT to the first donor-CU.

[0134] Figure 15 is a flowchart of another signaling method for topology regression in an embodiment of this application, illustrating the case where topology regression occurs simultaneously with switchover preparation when an IAB node (boundary node) switches from a non-F1-terminating CU to an F1-terminating CU. That is, the switchover request message includes a topology regression request, which can further reduce uplink data drops and service interruptions compared to Figure 14.

[0135] - The boundary node sends a measurement report to the target donor-CU, triggering a switchover preparation that initiates the non-F1-terminating CU (target donor-CU) to revert to the F1-terminating CU (source donor-CU). The switchover request message includes a topology reversion request, which may include information such as: a request to assign IP addresses for F1 or non-F1 services if the transition node is present; and a request to assign IP addresses for F1 and non-F1 services if the child node is present.

[0136] - If the boundary node is switched back to the original donor-DU, configure the boundary node with routing information in the F1-terninated CU topology domain for the original routing ID, configure new RLC channel mapping information belonging to the F1-terminating CU topology, request the original donor-DU to assign IP addresses for the boundary node's F1 and non-F1 services, and request the original donor-DU to assign IP addresses for the child nodes' F1 and non-F1 services. If the boundary node is not switched back to the original donor-DU, configure the boundary node with inter-donor-DU rewriting information in the F1-terminating CU domain, configure the boundary node with routing information in the F1-terninated CU topology domain for the replaced routing ID, configure new RLC channel mapping information belonging to the F1-terminating CU topology, request the new donor-DU to assign IP addresses for the boundary node's F1 and non-F1 services, and request the new donor-DU to assign IP addresses for the child nodes' F1 and non-F1 services.

[0137] - The source donor-CU uses an F1AP message to send the aforementioned inter-donor-DU rewriting information, routing information, and RLC channel mapping information to the boundary node, and releases the following configuration: BAP Header Rewriting Information, a routing table for the Non-F1-terminating CU area, and RLC channel mapping information where the address of the preceding hop node belongs to the F1-terminating CU topology and the address of the next hop node belongs to the non-F1-terminating CU topology.

[0138] - The source donor-CU sends an RRC reconfiguration message to the child node (including the IP addresses assigned by the new donor-DU or the original donor-DU under the F1-terminating-CU for F1 and non-F1 services).

[0139] - The source donor-CU sends a switch request response Xn message to the target donor-CU, which includes a switch instruction RRC message about the boundary node.

[0140] - The target donor-CU sends an instruction RRC reconfiguration message to switch to the boundary node (including the IP addresses assigned by the new donor-DU or the original donor-DU under the F1-terminating-CU for F1 and non-F1 services).

[0141] - The boundary node executes a random access procedure for switching.

[0142] - (Optional) The source donor-CU updates the routing table and RLC channel mapping table for the nodes along the original path.

[0143] - The boundary node applies the configured IP address when the switchover is complete.

[0144] - The child node will apply the configured IP address when the boundary node switchover is complete.

[0145] - After the boundary node's regression is complete, the source donor-CU sends a release request for the UE context for the boundary node-MT to the target donor-CU.

[0146] - Source donor-CU / target donor-CU releases XnAP indicators for boundary nodes.

[0147] The signaling process described above is for illustrative purposes only in illustrating the embodiments of this application, but is not limited thereto, and further references to related technologies can be found for more specific details of signaling.

[0148] In some embodiments, the second donor-CU sends a topology regression request to the first donor-CU before sending a switch request for the IAB-MT to switch to the first donor-CU.

[0149] When performing a topology regression before switchover preparation, the signaling process is similar to that shown in Figure 15. The difference is, for example, that the topology regression request is a separate Xn message. Also, because it is a separate Xn message, the topology regression request can instruct the source donor-CU to carry the assigned IP address in the switchover command RRC message included in the switchover preparation response, rather than in the topology regression response message. This allows the boundary node to immediately apply the configured IP address when the switchover is complete.

[0150] The above provides an illustrative example of a handover scenario, but this application is not limited to this. The following describes the re-establishment scenario and the dual connection scenario, but the same content will be omitted here.

[0151] In some embodiments, the first donor-CU sends a path transition setting for uplink data after the IAB-MT of the IAB node has re-established itself to the second donor-CU. In such scenarios, the first donor-CU can trigger the second donor-CU to initiate a topology retreat request, for example, when the IAB-MT re-establishes itself to the first donor-CU, the first donor-CU can trigger the second donor-CU to initiate a topology retreat request when it requests the second donor-CU to obtain context information for the IAB-MT.

[0152] In some embodiments, the IAB-MT of an IAB node establishes dual connections with the first and second donor-CUs. In such scenarios, for example, a topology regression request includes indicator information for a service where the transmission path is migrated from the second donor-CU to the first donor-CU.

[0153] The embodiments described above are for illustrative purposes to illustrate the embodiments of this application, but this application is not limited thereto, and appropriate modifications can be made based on the embodiments described above. For example, the embodiments described above may be used individually, or a combination of several of the embodiments described above may be used.

[0154] As can be seen from the above embodiment, when the uplink service transmission path of an IAB node or child node is migrated from the second donor-CU to the first donor-CU, the network device receives the path migration setting for the uplink data transmitted; and the IAB node or child node applies the path migration setting, of which the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU. This reduces or avoids the problem of uplink data being dropped, reduces transmission delay, and decreases service interruption time.

[0155] <Example of the third side> An embodiment of this application provides an IAB node device, the same content as described in the embodiments of the first and second aspects is omitted here. The device may be, for example, an IAB node or a child node in an IAB system, or one or more components, assemblies, or modules located on the IAB node or child node. The transmission path for the uplink service of the IAB node device is transferred from a first donor central unit to a second donor central unit, and then from the second donor central unit to the first donor central unit.

[0156] Figure 16 shows an IAB node device in an embodiment of the present application. As shown in Figure 16, the IAB node device 1600 includes a receiving unit 1601 and a processing unit 1602. The receiving unit 1601 receives the path transition settings for the uplink data transmitted by the network device, and the processing unit 1602 applies the path transition settings, in which the IAB-DU of the IAB node maintains an F1 connection with the first Donor-CU.

[0157] In some embodiments, the transmission path for the uplink service of an IAB node transitions from the first donor distributed unit (donor-DU) of the first donor-CU to the second donor-DU of the second donor-CU, and then from the second donor-DU of the second donor-CU to the first donor-DU of the first donor-CU.

[0158] In some embodiments, the path transition settings are sent from the first donor-CU to the IAB node or child node via an F1AP message or RRC message.

[0159] In some embodiments, the path transition configuration includes, namely, an increase in routing configuration to indicate a mapping relationship between a first routing marker and the BAP address of the next hop node of the IAB node, and an increase in first RLC channel mapping configuration to indicate a mapping relationship between the BAP address of the preceding hop node of the IAB node, the inlet link radio link control (RLC) channel marker and the BAP address of the next hop node of the IAB node, and the exit link RLC channel marker, where the first routing marker, the BAP address of the preceding hop node of the IAB node and the BAP address of the next hop node of the IAB node belong to the network topology domain of the first Donor-CU, and the destination BAP address of the first routing marker is the BAP address of the first donor-DU.

[0160] In some embodiments, the receiver 1601 receives the path transition settings before the IAB-MT switches from the second donor-CU to the first donor-CU.

[0161] In some embodiments, the path transition configuration further includes, namely, the release of a donor-CU inter-routing sign rewrite configuration to indicate a mapping relationship between a first routing sign and a second routing sign; the release of a routing configuration to indicate a mapping relationship between the second routing sign and the BAP address of the next-hop node of the IAB node; or the release of a second RLC channel mapping configuration to indicate a mapping relationship between the address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next-hop node of the IAB node, and the exit link RLC channel sign, wherein the first routing sign and the BAP address of the preceding hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the first routing sign is the BAP address of the first donor-DU, the second routing sign and the BAP address of the next-hop node of the IAB node belong to the network topology domain of the second donor-CU, and the destination BAP address of the second routing sign is the BAP address of the second donor-DU.

[0162] In some embodiments, the receiving unit 1601 further receives configuration information to configure the IP address anchored to the second donor-DU to be replaced with the IP address anchored to the first donor-DU, the IP address of which is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or the child node.

[0163] In some embodiments, the receiving unit 1601 receives the configuration information before the IAB-MT performs the switch from the second donor-CU to the first donor-CU.

[0164] When the IAB-MT has completed switching from the second donor-CU to the first donor-CU, the processing unit 1602 replaces the IP address anchored to the second donor-DU with the IP address anchored to the first donor-DU.

[0165] In some embodiments, configuration information for the IAB node is transmitted via a switching command radio resource control (RRC) message or an RRC reset message, and configuration information for the child node is transmitted via an RRC reset message.

[0166] In some embodiments, the configuration information is IP address configuration information for the BAP address of the first donor-DU. For example, this configuration information is used to change the IP address anchored to the second donor-DU for the BAP address of the first donor-DU to the IP address anchored to the first donor-DU.

[0167] In some embodiments, the transmission path for the uplink service of the IAB node is transitioned from the first donor-DU of the first donor-CU to the second donor-DU of the second donor-CU, and then from the second donor-DU of the second donor-CU to the third donor-DU of the first donor-CU. The path transition setting is sent by the first donor-CU to the IAB node or child node via an F1AP message.

[0168] In some embodiments, the path transition settings include the following: an increase in donor-DU routing sign rewrite settings to indicate the mapping relationship between the first routing sign and the third routing sign; an increase in routing settings to indicate the mapping relationship between the third routing sign and the BAP address of the next hop node of the IAB node; and an increase in the first RLC channel mapping settings to indicate the mapping relationship between the BAP address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next hop node of the IAB node and the exit link RLC channel sign, wherein the first routing sign, the third routing sign, the BAP address of the preceding hop node of the IAB node and the BAP address of the next hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the third routing sign is the BAP address of the third donor-DU, and the destination BAP address of the first routing sign is the BAP address of the first donor-DU.

[0169] In some embodiments, the receiver 1601 receives the path transition settings before the IAB-MT switches from the second donor-CU to the third donor-CU.

[0170] In some embodiments, the path transition configuration further includes, namely, the release of a donor-CU inter-routing sign rewrite configuration to indicate a mapping relationship between a first routing sign and a second routing sign; the release of a routing configuration to indicate a mapping relationship between the second routing sign and the BAP address of the next-hop node of the IAB node; or the release of a second RLC channel mapping configuration to indicate a mapping relationship between the address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next-hop node of the IAB node, and the exit link RLC channel sign, wherein the first routing sign and the BAP address of the preceding hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the first routing sign is the BAP address of the first donor-DU, the second routing sign and the BAP address of the next-hop node of the IAB node belong to the network topology domain of the second donor-CU, and the destination BAP address of the second routing sign is the BAP address of the second donor-DU.

[0171] In some embodiments, the receiving unit 1601 further receives configuration information to configure the IP address anchored to the third donor-DU to replace the IP address anchored to the second donor-DU, the IP address of which is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or the child node.

[0172] In some embodiments, the receiving unit 1601 receives configuration information before the IAB-MT switches from the second donor-CU to the first donor-CU, and the processing unit 1602 replaces the IP address anchored to the second donor-DU with the IP address anchored to the third donor-DU when the IAB-MT has finished switching from the second donor-CU to the first donor-CU.

[0173] In some embodiments, configuration information for the IAB node is transmitted via a switching command radio resource control (RRC) message or an RRC reset message, and configuration information for the child node is transmitted via an RRC reset message.

[0174] In some embodiments, the configuration information is IP address configuration information for the BAP address of the first donor-DU. For example, this configuration information is used to change the IP address anchored to the second donor-DU for the BAP address of the first donor-DU to the IP address anchored to the third donor-DU.

[0175] The embodiments described above are for illustrative purposes to illustrate the embodiments of this application, but this application is not limited thereto, and appropriate modifications can be made based on the embodiments described above. For example, the embodiments described above may be used individually, or a combination of several of the embodiments described above may be used.

[0176] Although only the components or modules relevant to this application have been described above, this application is not limited thereto. The IAB node device 1600 in the embodiments of this application may further include other components or modules, and the specific details of these components or modules can be found in the relevant art.

[0177] Furthermore, for convenience, Figure 16 only shows the connection relationships or signal directions between each component or module; however, various related technologies such as bus connections may be employed so as can be understood by those skilled in the art. The above-mentioned components or modules may be implemented by hardware such as processors, memory devices, transmitters, and receivers, but the implementation of this application is not limited to these.

[0178] As can be seen from the above embodiment, the IAB node or child node receives the path transition settings for the uplink data transmitted by the network device; and the IAB node or child node applies the path transition settings, in which case the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU. This reduces or avoids the problem of uplink data being dropped, reduces transmission delay, and reduces service interruption time.

[0179] <Example of the fourth side> An IAB donor device is provided in the embodiments of this application, and the same description as in the embodiments of the first to third aspects is omitted here. The device may be, for example, an IAB donor-CU in an IAB system, or one or more components, assemblies, or modules located in the IAB donor-CU.

[0180] The IAB system includes an IAB-donor device and an IAB node. The transmission path for the uplink service of the IAB node transitions from the first donor central unit to the second donor central unit, and then from the second donor central unit to the first donor central unit.

[0181] Figure 17 shows an IAB donor device in an embodiment of the present application. As shown in Figure 17, the IAB donor device 1700 includes a receiver 1701 and a transmitter 1702. The receiver 1701 receives a topology regression request transmitted by the second donor-CU; and the transmitter 1702 transmits path transition settings for uplink data, of which the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU.

[0182] In some embodiments, the transmitter 1702 transmits path transition settings to the IAB node or child node via an F1AP message or RRC message.

[0183] In some embodiments, the topology regression request includes an IP address anchored to the second donor-DU for the BAP address of the first donor-DU, of which the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node.

[0184] In some embodiments, the second donor-CU sends a topology regression request to the first donor-CU before sending a switching request for the IAB-MT to the first donor-CU; or the second donor-CU includes the topology regression request in the switching request for the IAB-MT to the first donor-CU; or the second donor-CU sends a topology regression request to the first donor-CU after sending the switching request for the IAB-MT to the first donor-CU.

[0185] In some embodiments, the transmitting unit 1702 transmits to the second donor-CU configuration information to configure the IP address anchored to the first donor-DU to replace the IP address anchored to the second donor-DU, or to configure the IP address anchored to the third donor-DU to replace the IP address anchored to the second donor-DU.

[0186] In some embodiments, the configuration information is included in the RRC reconfiguration message, which is included in the switching request response message for switching to the first donor-CU of the IAB-MT.

[0187] The embodiments described above are for illustrative purposes to illustrate the embodiments of this application, but this application is not limited thereto, and appropriate modifications can be made based on the embodiments described above. For example, the embodiments described above may be used individually, or a combination of several of the embodiments described above may be used.

[0188] Although only the components or modules relevant to this application have been described above, this application is not limited thereto. The IAB donor device 1700 in the embodiments of this application may further include other components or modules, and the specific details of these components or modules can be found in the relevant art.

[0189] Furthermore, for convenience, Figure 17 only shows the connection relationships or signal directions between each component or module; however, various related technologies such as bus connections may be employed so as can be understood by those skilled in the art. The above-mentioned components or modules may be realized by hardware such as processors, memory devices, transmitters, and receivers, but the implementation of this application is not limited to these.

[0190] As can be seen from the above embodiment, when an IAB node or child node transitions the transmission path of the IAB node's uplink service from the second donor-CU to the first donor-CU, it receives the path transition setting for the uplink data transmitted by the network device; and the IAB node or child node applies the path transition setting, and the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU. This reduces or avoids the problem of uplink data being dropped, reduces transmission delay, and decreases service interruption time.

[0191] <Example of the fifth side> The embodiments of this application provide a communication system which includes a donor device and an IAB node. Further details regarding the network architecture of the donor device and IAB node can be found in related technologies, and are therefore omitted here.

[0192] In embodiments of this application, an IAB device is further provided, which may be an IAB donor device or an IAB node device (IAB node or child node).

[0193] Figure 18 shows an IAB device in an embodiment of the present application. As shown in Figure 18, the IAB device 1800 may include a processor (e.g., a central processor CPU) 1801 and a memory unit 1802, the memory unit 1802 being connected to the processor 1801. The memory unit 1802 can store various types of data, and can also store a program 1805 for information processing, and can execute the program 1805 under the control of the central processor 1801.

[0194] For example, the processor 1801 may be configured to execute a program to implement the topology regression method in the embodiment of the first aspect. For example, the processor 1801 may be configured to perform the following control: namely, receive path transition settings for uplink data transmitted by a network device; and apply the path transition settings, of which the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU.

[0195] Furthermore, for example, the processor 1801 may be configured to execute a program to implement the topology regression method in the embodiment of the second aspect. For example, the processor 1801 may be configured to perform the following control: namely, receiving a topology regression request transmitted by the second donor-CU; and transmitting a path transition setting for uplink data, of which the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU.

[0196] Furthermore, as shown in Figure 18, the IAB device 1800 may also include a transceiver 1803, an antenna 1804, etc., and the functions of these components are similar to those of the prior art, so a detailed explanation is omitted here. Note that the IAB device 1800 does not need to include all the components shown in Figure 18. In addition, the IAB device 1800 may also include components not shown in Figure 18, for which prior art can be referenced.

[0197] In embodiments of this application, a computer-readable program is further provided, wherein when the program is executed on an IAB node device, the program causes the computer to execute the topology regression method in the embodiment of the first aspect on the IAB node device.

[0198] In the embodiments of this application, a storage medium storing a computer-readable program is further provided, wherein the computer-readable program causes a computer to execute the topology regression method in the embodiment of the first aspect on an IAB node device.

[0199] In embodiments of this application, a computer-readable program is further provided, wherein when the program is executed on an IAB donor device, the program causes the computer to execute the pology regression method in the embodiment of the second aspect on the IAB donor device.

[0200] In the embodiments of this application, a storage medium storing a computer-readable program is further provided, wherein the computer-readable program causes a computer to execute the topology regression method in the second embodiment on an IAB donor device.

[0201] Furthermore, the above-described apparatus and method may be implemented by software or hardware, or by a combination of hardware and software. The present invention further relates to a computer-readable program as described below, that is, the program, when executed by a logic component, causes the logic component to implement the above-described apparatus or component, or to the logic component to implement the above-described various methods or steps. The logic component may be, for example, an FPGA (Field Programmable Gate Array), a microprocessor, or a processor used in a computer. The present invention further relates to a storage medium storing the above-described program, for example, a hard disk, a magnetic disk, an optical hard disk, a DVD, a flash memory, etc.

[0202] Furthermore, one or more combinations of the functional blocks shown in the drawings and / or one or more combinations of functional blocks may 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 component, discrete gate or transistor logic component, discrete hardware assembly or any other suitable combination for performing the functions described herein. Also, one or more combinations of the functional blocks shown in the drawings and / or one or more combinations of functional blocks may further be configured as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors connected to a DSP by communication or any other combination of any other configuration.

[0203] Although preferred embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and any modifications to the present invention that do not deviate from the spirit of the invention fall within the technical scope of the present invention.

[0204] Furthermore, the following additional information is disclosed regarding the above-mentioned embodiments.

[0205] (Note 1) A method of topology regression, After the transmission path for the uplink service of the IAB node is migrated from the first donor centrifuge unit (donor-CU) to the second donor centrifuge unit, it is then migrated from the second donor centrifuge unit back to the first donor centrifuge unit. The aforementioned method, The IAB node or child node receives the path transition settings for the uplink data transmitted by the network device; and This includes the application of the path transition settings by the IAB node or child node, In this method, the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU.

[0206] (Note 2) The method described in Appendix 1, A method in which the IAB node or child node receives the path transition settings for the uplink data transmitted by the network device before the IAB-MT of the IAB node is switched from the second donor-CU to the first donor-CU or after it has been switched to the first donor-CU.

[0207] (Note 3) The method described in Appendix 2, A method in which the transmission path for the uplink service of the IAB node is transferred from the first donor distributed unit (donor-DU) of the first donor-CU to the second donor-DU of the second donor-CU, and then from the second donor-DU of the second donor-CU to the first donor-DU of the first donor-CU.

[0208] (Note 4) The method described in Appendix 3, The path transition setting is transmitted by the first donor-CU to the IAB node or child node via an F1AP message or an RRC message.

[0209] (Note 5) The method described in Appendix 3 or 4, The aforementioned path transition settings include, namely, an increase in routing settings to indicate the mapping relationship between the first routing marker and the BAP address of the next hop node of the IAB node, and an increase in first RLC channel mapping settings to indicate the mapping relationship between the BAP address of the preceding hop node of the IAB node, the inlet link radio link control (RLC) channel marker and the BAP address of the next hop node of the IAB node, and the exit link RLC channel marker. The first routing indicator, the BAP address of the preceding hop node of the IAB node, and the BAP address of the next hop node of the IAB node belong to the network topology domain of the first Donor-CU, and the destination BAP address of the first routing indicator is the BAP address of the first donor-DU, in this method.

[0210] (Note 6) The method described in Appendix 5, A method in which the IAB node or child node receives the path transition settings before the IAB-MT performs the switch from the second donor-CU to the first donor-CU.

[0211] (Note 7) The method described in Appendix 5, The aforementioned path transition setting further includes, namely, the release of a donor-CU routing sign rewrite setting to indicate the mapping relationship between the first routing sign and the second routing sign, the release of a routing setting to indicate the mapping relationship between the second routing sign and the BAP address of the next hop node of the IAB node, or the release of a second RLC channel mapping setting to indicate the mapping relationship between the address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next hop node of the IAB node and the exit link RLC channel sign. The method wherein the BAP addresses of the first routing marker and the preceding hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the first routing marker is the BAP address of the first donor-DU, the BAP addresses of the second routing marker and the next hop node of the IAB node belong to the network topology domain of the second donor-CU, and the destination BAP address of the second routing marker is the BAP address of the second donor-DU.

[0212] (Note 8) A method according to any one of the items in Appendix 5 to 7, further, A method wherein the IAB node or child node receives configuration information to configure it to replace the IP address anchored to the second donor-DU with the IP address anchored to the first donor-DU, and the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node.

[0213] (Note 9) The method described in Appendix 8, A method by which the IAB node or child node receives the configuration information before the IAB-MT performs a switch from the second donor-CU to the first donor-CU.

[0214] (Note 10) The method described in Appendix 8, further, A method in which the IAB node or child node replaces the IP address anchored to the second donor-DU with the IP address anchored to the first donor-DU.

[0215] (Note 11) A method according to any one of the appendices 8 to 10, The configuration information of the IAB node is transmitted by a switching command radio resource control (RRC) message or an RRC reset message, and the configuration information of the child node is transmitted by an RRC reset message.

[0216] (Note 12) A method according to any one of the appendices 8 to 11, The configuration information is the IP address configuration information for the BAP address of the first donor-DU, in this method.

[0217] (Note 13) The method described in Appendix 12, The configuration information is used to change the IP address anchored to the second donor-DU for the BAP address of the first donor-DU to the IP address anchored to the first donor-DU.

[0218] (Note 14) The method described in Appendix 2, A method in which the transmission path for the uplink service of the IAB node is transitioned from the first donor-DU of the first donor-CU to the second donor-DU of the second donor-CU, and then from the second donor-DU of the second donor-CU to the third donor-DU of the first donor-CU.

[0219] (Note 15) The method described in Appendix 14, The path transition setting is transmitted by the first donor-CU to the IAB node or child node via an F1AP message or an RRC message.

[0220] (Note 16) The method described in Appendix 14 or 15, The path transition settings include, namely, an increase in donor-DU routing sign rewrite settings to indicate a mapping relationship between a first routing sign and a third routing sign, an increase in routing settings to indicate a mapping relationship between a third routing sign and the BAP address of the next hop node of the IAB node, and an increase in first RLC channel mapping settings to indicate a mapping relationship between the BAP address of the preceding hop node of the IAB node, an inlet link RLC channel sign and the BAP address of the next hop node of the IAB node and an outlet link RLC channel sign, wherein the first routing sign, the third routing sign, the BAP address of the preceding hop node of the IAB node and the BAP address of the next hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the third routing sign is the BAP address of the third donor-DU, and the destination BAP address of the first routing sign is the BAP address of the first donor-DU.

[0221] (Note 17) The method described in any one of the appendices 14 to 16, A method by which the IAB node or child node receives the path transition settings before the IAB-MT performs the switch from the second donor-CU to the third donor-CU.

[0222] (Note 18) The method described in Appendix 16, The aforementioned path transition setting further includes, namely, the release of a donor-CU routing sign rewrite setting to indicate the mapping relationship between the first routing sign and the second routing sign, the release of a routing setting to indicate the mapping relationship between the second routing sign and the BAP address of the next hop node of the IAB node, or the release of a second RLC channel mapping setting to indicate the mapping relationship between the address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next hop node of the IAB node and the exit link RLC channel sign. The method wherein the BAP addresses of the first routing marker and the preceding hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the first routing marker is the BAP address of the first donor-DU, the BAP addresses of the second routing marker and the next hop node of the IAB node belong to the network topology domain of the second donor-CU, and the destination BAP address of the second routing marker is the BAP address of the second donor-DU.

[0223] (Note 19) A method according to any one of the appendices 16 to 19, further, A method wherein the IAB node or child node receives configuration information to configure it to replace the IP address anchored to the second donor-DU with the IP address anchored to the third donor-DU, and the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node.

[0224] (Note 20) The method described in Appendix 19, A method by which the IAB node or child node receives the configuration information before the IAB-MT performs a switch from the second donor-CU to the first donor-CU.

[0225] (Note 21) The method described in Appendix 19, further, A method in which the IAB node or child node replaces the IP address anchored to the second donor-DU with the IP address anchored to the third donor-DU.

[0226] (Note 22) The method described in any one of the appendices 19 to 21, The configuration information of the IAB node is transmitted by a switching command radio resource control (RRC) message or an RRC reset message, and the configuration information of the child node is transmitted by an RRC reset message.

[0227] (Note 23) The method described in any one of the appendices 19 to 22, The aforementioned configuration information is the IP address configuration information for the BAP address of the first donor-DU, according to the method.

[0228] (Note 24) The method described in Appendix 23, The configuration information is used to change the IP address anchored to the second donor-DU for the BAP address of the first donor-DU to the IP address anchored to the third donor-DU.

[0229] (Note 25) The method described in Appendix 1, A method in which the IAB node or child node receives the path transition settings for the uplink data transmitted by the network device after the IAB-MT of the IAB node has re-established with the second donor-CU.

[0230] (Note 26) The method described in Appendix 25, A method in which the transmission path for the uplink service of the IAB node transitions from the first donor distributed unit (donor-DU) of the first donor-CU to the second donor-DU of the second donor-CU, and then from the second donor-DU of the second donor-CU to the first donor-DU of the first donor-CU.

[0231] (Note 27) The method described in Appendix 26, The path transition setting is transmitted by the first donor-CU to the IAB node or child node via an F1AP message or an RRC message.

[0232] (Note 28) The method described in Appendix 26 or 27, The aforementioned path transition settings include, namely, an increase in routing settings to indicate the mapping relationship between the first routing marker and the BAP address of the next hop node of the IAB node, and an increase in the first RLC channel mapping settings to indicate the mapping relationship between the BAP address of the preceding hop node of the IAB node, the inlet link radio link control (RLC) channel marker and the BAP address of the next hop node of the IAB node, and the exit link RLC channel marker. The first routing indicator, the BAP address of the preceding hop node of the IAB node, and the BAP address of the next hop node of the IAB node belong to the network topology domain of the first Donor-CU, and the destination BAP address of the first routing indicator is the BAP address of the first donor-DU, in this method.

[0233] (Note 29) The method described in Appendix 28, The aforementioned path transition setting further includes, namely, the release of a donor-CU routing sign rewrite setting to indicate the mapping relationship between the first routing sign and the second routing sign, the release of a routing setting to indicate the mapping relationship between the second routing sign and the BAP address of the next hop node of the IAB node, or the release of a second RLC channel mapping setting to indicate the mapping relationship between the address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next hop node of the IAB node and the exit link RLC channel sign. The method wherein the BAP addresses of the first routing marker and the preceding hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the first routing marker is the BAP address of the first donor-DU, the BAP addresses of the second routing marker and the next hop node of the IAB node belong to the network topology domain of the second donor-CU, and the destination BAP address of the second routing marker is the BAP address of the second donor-DU.

[0234] (Note 30) The method described in Appendix 28 or 29, further, A method wherein the IAB node or child node receives configuration information to configure it to replace the IP address anchored to the second donor-DU with the IP address anchored to the first donor-DU, and the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node.

[0235] (Note 31) The method described in Appendix 30, The configuration information is the IP address configuration information for the BAP address of the first donor-DU, in this method.

[0236] (Note 32) The method described in Appendix 31, The configuration information is used to change the IP address anchored to the second donor-DU for the BAP address of the first donor-DU to the IP address anchored to the first donor-DU.

[0237] (Note 33) The method described in Appendix 25, A method in which the transmission path for the uplink service of the IAB node transitions from the first donor-DU of the first donor-CU to the second donor-DU of the second donor-CU, and then from the second donor-DU of the second donor-CU to the third donor-DU of the first donor-CU.

[0238] (Note 34) The method described in Appendix 33, The path transition setting is transmitted by the first donor-CU to the IAB node or child node via an F1AP message or an RRC message.

[0239] (Note 35) The method described in Appendix 33 or 34, The aforementioned path transition settings include, namely, an increase in donor-DU routing sign rewriting settings to indicate the mapping relationship between the first routing sign and the third routing sign, an increase in routing settings to indicate the mapping relationship between the third routing sign and the BAP address of the next hop node of the IAB node, and an increase in the first RLC channel mapping settings to indicate the mapping relationship between the BAP address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next hop node of the IAB node, and the exit link RLC channel sign. The first routing marker, the third routing marker, the BAP address of the preceding hop node of the IAB node, and the BAP address of the next hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the third routing marker is the BAP address of the third donor-DU, and the destination BAP address of the first routing marker is the BAP address of the first donor-DU, in this method.

[0240] (Note 36) The method described in Appendix 35, The aforementioned path transition setting further includes, namely, the release of a donor-CU routing sign rewrite setting to indicate the mapping relationship between the first routing sign and the second routing sign, the release of a routing setting to indicate the mapping relationship between the second routing sign and the BAP address of the next hop node of the IAB node, or the release of a second RLC channel mapping setting to indicate the mapping relationship between the address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next hop node of the IAB node and the exit link RLC channel sign. The method wherein the BAP addresses of the first routing marker and the preceding hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the first routing marker is the BAP address of the first donor-DU, the BAP addresses of the second routing marker and the next hop node of the IAB node belong to the network topology domain of the second donor-CU, and the destination BAP address of the second routing marker is the BAP address of the second donor-DU.

[0241] (Note 37) The method described in Appendix 35 or 36, further, The IAB node or child node receives configuration information for setting to replace the IP address anchored to the second donor-DU with the IP address anchored to the third donor-DU, wherein the IP address is used for the F1 user plane data, F1 control plane data or non-F1 data of the IAB node or the child node, method.

[0242] (Appendix 38) The method according to Appendix 37, wherein the configuration information is IP address configuration information about the BAP address of the first donor-DU, method.

[0243] (Appendix 39) The method according to Appendix 38, wherein the configuration information is used to change the IP address anchored to the second donor-DU to the IP address anchored to the third donor-DU for the BAP address of the first donor-DU, method.

[0244] (Appendix 40) The method according to Appendix 1, wherein the IAB-MT of the IAB node establishes a dual connection with the first donor-CU and the second donor-CU, method.

[0245] (Appendix 41) The method according to Appendix 40, wherein the transmission path of the uplink service of the IAB node migrates from the first donor-DU of the first donor-CU to the second donor-DU of the second donor-CU and then migrates from the second donor-DU of the second donor-CU to the first donor-DU of the first donor-CU, method.

[0246] (Appendix 42) The method according to Appendix 41, The path transition setting is a method in which the first donor-CU transmits to the IAB node or the child node by means of an F1AP message or an RRC message.

[0247] (Appendix 43) The method according to Appendix 41 or 42, The path transition setting includes the following, that is, an increase in routing settings for instructing a mapping relationship between a first routing label and the BAP address of the next-hop node of the IAB node, and the BAP address of the previous-hop node of the IAB node, the ingress link radio link control (RLC) channel label, and the BAP address of the next-hop node of the IAB node, and an increase in the first RLC channel mapping setting for instructing a mapping relationship with the egress link RLC channel label. The first routing label, the BAP address of the previous-hop node of the IAB node, and the BAP address of the next-hop node of the IAB node belong to the network topology domain of the first Donor-CU, and the destination BAP address of the first routing label is the BAP address of the first donor-DU.

[0248] (Appendix 44) The method according to Appendix 43, The path transition setting further includes the following, that is, a release of the donor-CU inter-routing label rewriting setting for instructing a mapping relationship between the first routing label and the second routing label, a release of the routing setting for instructing a mapping relationship between the second routing label and the BAP address of the next-hop node of the IAB node, or a release of the second RLC channel mapping setting for instructing a mapping relationship between the address of the previous-hop node of the IAB node, the ingress link RLC channel label, and the BAP address of the next-hop node of the IAB node, and the egress link RLC channel label. The method wherein the BAP addresses of the first routing marker and the preceding hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the first routing marker is the BAP address of the first donor-DU, the BAP addresses of the second routing marker and the next hop node of the IAB node belong to the network topology domain of the second donor-CU, and the destination BAP address of the second routing marker is the BAP address of the second donor-DU.

[0249] (Note 45) The method described in Appendix 43 or 44, further, A method wherein the IAB node or child node receives configuration information to configure it to replace the IP address anchored to the second donor-DU with the IP address anchored to the first donor-DU, and the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node.

[0250] (Note 46) The method described in Appendix 45, The configuration information is the IP address configuration information for the BAP address of the first donor-DU, in this method.

[0251] (Note 47) The method described in Appendix 46, The configuration information is used to change the IP address anchored to the second donor-DU for the BAP address of the first donor-DU to the IP address anchored to the first donor-DU.

[0252] (Note 48) The method described in Appendix 40, A method in which the transmission path for the uplink service of the IAB node transitions from the first donor-DU of the first donor-CU to the second donor-DU of the second donor-CU, and then from the second donor-DU of the second donor-CU to the third donor-DU of the first donor-CU.

[0253] (Note 49) The method described in Appendix 48, The path transition setting is transmitted by the first donor-CU to the IAB node or child node via an F1AP message or an RRC message.

[0254] (Note 50) The method described in Appendix 48 or 49, The aforementioned path transition settings include, namely, an increase in donor-DU routing sign rewriting settings to indicate the mapping relationship between the first routing sign and the third routing sign, an increase in routing settings to indicate the mapping relationship between the third routing sign and the BAP address of the next hop node of the IAB node, and an increase in the first RLC channel mapping settings to indicate the mapping relationship between the BAP address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next hop node of the IAB node, and the exit link RLC channel sign. The first routing marker, the third routing marker, the BAP address of the preceding hop node of the IAB node, and the BAP address of the next hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the third routing marker is the BAP address of the third donor-DU, and the destination BAP address of the first routing marker is the BAP address of the first donor-DU, in this method.

[0255] (Note 51) The method described in Appendix 50, The aforementioned path transition setting further includes, namely, the release of a donor-CU routing sign rewrite setting to indicate the mapping relationship between the first routing sign and the second routing sign, the release of a routing setting to indicate the mapping relationship between the second routing sign and the BAP address of the next hop node of the IAB node, or the release of a second RLC channel mapping setting to indicate the mapping relationship between the address of the preceding hop node of the IAB node, the inlet link RLC channel sign and the BAP address of the next hop node of the IAB node and the exit link RLC channel sign. The method wherein the BAP addresses of the first routing marker and the preceding hop node of the IAB node belong to the network topology domain of the first donor-CU, the destination BAP address of the first routing marker is the BAP address of the first donor-DU, the BAP addresses of the second routing marker and the next hop node of the IAB node belong to the network topology domain of the second donor-CU, and the destination BAP address of the second routing marker is the BAP address of the second donor-DU.

[0256] (Note 52) The method described in Appendix 50 or 51, further, A method wherein the IAB node or child node receives configuration information to configure it to replace the IP address anchored to the second donor-DU with the IP address anchored to the third donor-DU, and the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node.

[0257] (Note 53) The method described in Appendix 52, The configuration information is the IP address configuration information for the BAP address of the first donor-DU, in this method.

[0258] (Appendix 54) The method described in Appendix 53, wherein the configuration information is used to change the IP address anchored to the second donor-DU for the BAP address of the first donor-DU to the IP address anchored to the third donor-DU.

[0259] (Appendix 55) A topology fallback method, where after migrating the transmission path of the uplink service of the IAB node from the first donor central unit (donor-CU) to the second donor central unit, it migrates from the second donor central unit to the first donor central unit, the method comprising: the first donor-CU receiving a topology fallback request from the second donor-CU; and the first donor-CU transmitting a path migration setting for uplink data, wherein the IAB-DU of the IAB node maintains an F1 connection with the first donor-CU.

[0260] (Appendix 56) The method described in Appendix 55, where the transmission path of the uplink service of the IAB node migrates from the first donor distributed unit (donor-DU) of the first donor-CU to the second donor-DU of the second donor-CU, and then migrates from the second donor-DU of the second donor-CU to the first donor-DU of the first donor-CU.

[0261] (Appendix 57) The method described in Appendix 55, where the transmission path of the uplink service of the IAB node migrates from the first donor-DU of the first donor-CU to the second donor-DU of the second donor-CU, and then migrates from the second donor-DU of the second donor-CU to the third donor-DU of the first donor-CU.

[0262] (Note 58) A method according to any one of the appendices 55 to 57, A method wherein the first donor-CU transmits the path transition settings to the IAB node or the child node via an F1AP message or an RRC message.

[0263] (Note 59) A method according to any one of the appendices 55 to 58, The topology regression request includes the IP address anchored to the second donor DU for the BAP address of the first donor DU, A method wherein the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node.

[0264] (Note 60) A method according to any one of the appendices 55 to 59, further, A method comprising: the first donor-CU transmitting to the second donor-CU configuration information to configure the first donor-CU to replace the IP address anchored to the first donor-DU with the IP address anchored to the second donor-DU, or configuration information to configure the second donor-CU to replace the IP address anchored to the third donor-DU with the IP address anchored to the third donor-DU.

[0265] (Note 61) The method described in any one of the appendices 55 to 60, A method in which the first donor-CU transmits the path transition settings for uplink data before the IAB-MT of the IAB node is switched from the second donor-CU to the first donor-CU or after it has been switched to the first donor-CU.

[0266] (Note 62) The method described in Appendix 61, A method wherein the second donor-CU sends the topology regression request to the first donor-CU before sending the switching request for the IAB-MT to the first donor-CU.

[0267] (Note 63) The method described in Appendix 61, A method in which the second donor-CU includes the topology regression request in a switching request for the IAB-MT to switch to the first donor-CU.

[0268] (Note 64) The method described in Appendix 63, The configuration information is included in the RRC reconfiguration message included in the switching request response message for the IAB-MT switching to the first donor-CU, in a manner that

[0269] (Note 65) The method described in Appendix 61, A method wherein the second donor-CU transmits a switching request for the IAB-MT to the first donor-CU, and then transmits the topology regression request to the first donor-CU.

[0270] (Note 66) The method described in any one of the appendices 55 to 60, The first donor-CU transmits the path transition settings for the uplink data after the IAB-MT of the IAB node has re-established itself with the second donor-CU.

[0271] (Note 67) Among the severals listed in Appendix 66, A method wherein the first donor-CU triggers the second donor-CU to send the topology regression request to the first donor-CU.

[0272] (Note 68) The method described in any one of the appendices 55 to 60, The IAB-MT of the IAB node establishes a dual connection with the first donor-CU and the second donor-CU, in this manner.

[0273] (Note 69) The method described in Appendix 68, The topology regression request includes indicator information for a service in which the transmission path is transitioned from the second donor-CU to the first donor-CU.

[0274] (Note 70) IAB node device, Including memory and processing units, The memory device stores a computer program. The processor is configured to execute the computer program to realize the topology regression method described in any one of the appendices 1 to 54, in an IAB node device.

[0275] (Note 71) IAB donor device, Including memory and processing units, The memory device stores a computer program. An IAB donor device, wherein the processor is configured to execute the computer program to realize the topology regression method described in any one of appendices 55 to 69.

[0276] (Note 72) It is a communication system, This includes IAB donor devices and IAB node devices. A communication system in which the IAB node device is configured to perform the topology regression method described in any one of the appendices 1 to 54, and the IAB donor device is configured to perform the topology regression method described in any one of the appendices 55 to 69.

Claims

1. An IAB (Integrated Access and Backhaul) donor device applicable to a Centralized Unit (CU), A receiver configured to receive a first message transmitted by a second donor central unit, wherein the first message is used to migrate the transmission path of the uplink traffic of an IAB node from the second donor central unit back to the first donor central unit after the transmission path of the uplink traffic of the IAB node has migrated from the first donor central unit back to the second donor central unit; and Includes a transmitter configured to transmit the path transition settings for the uplink traffic to the IAB node based on the first message, The IAB-DU (Distributed Unit) of the IAB node is an IAB donor device that maintains an F1 connection with the first donor central unit.

2. IAB donor device according to claim 1, The first message includes the IP address anchored to the second donor distribution unit for the backhaul adaptive protocol address of the first donor distribution unit, The IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node in the IAB donor device.

3. IAB donor device according to claim 1, The transmitter is further configured to transmit configuration information to the second donor central unit. The aforementioned configuration information is used to configure an IAB donor device to replace an IP address anchored to a second donor distribution unit with an IP address anchored to a first donor distribution unit, or to replace an IP address anchored to a third donor distribution unit with an IP address anchored to the second donor distribution unit.

4. IAB donor device according to claim 1, IAB donor equipment, wherein the transmitter is configured to transmit the uplink traffic path transition settings before the IAB-MT (Mobile Terminal) of the IAB node is handed over from the second donor central unit to the first donor central unit or after it has been handed over to the first donor central unit.

5. IAB donor device according to claim 1, The transmitter is an IAB donor device configured to transmit the uplink traffic path transition settings after the IAB-MT of the IAB node has re-established itself with the second donor central unit.

6. IAB donor device according to claim 1, The IAB node is transferred from the first donor concentration unit to the second donor concentration unit, and then transferred from the second donor concentration unit to the first donor concentration unit; or The IAB-MT of the IAB node has established a dual connection with the first donor centralization unit and the second donor centralization unit, and is an IAB donor device.

7. IAB donor device according to claim 6, The IAB donor device, wherein the first message is a handover request message for the IAB-MT to be handed over to the first donor central unit.

8. IAB donor device according to claim 1, IAB donor device, wherein the transmitter is further configured to transmit a second message to the second donor central unit in order for the second donor central unit to transmit the first message.

9. IAB node device, After the transmission path of the uplink traffic of the IAB node is transferred from the first donor central unit to the second donor central unit, it is then transferred from the second donor central unit back to the first donor central unit. The aforementioned IAB node device is A receiver configured to receive path transition settings for the uplink traffic transmitted by the first donor central unit, wherein the first donor central unit is configured to receive a first message transmitted by the second donor central unit, the first message being used to transition the transmission path of the uplink traffic from the second donor central unit to the first donor central unit; and Includes a processor configured to apply the aforementioned path transition settings, The IAB-DU (Distributed Unit) of the IAB node is an IAB node device that maintains an F1 connection with the first donor central unit.

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