IAB node device, IAB donor device and route transition method

Abstract

The embodiment of the present invention provides an IAB node device, an IAB donor device and a path transition method, in which a parent node of an IAB node before transition uses a first donor distribution unit, and a parent node of an IAB node after transition uses a second donor distribution unit, the method includes: before an IAB-MT of an IAB node performs a handover, the IAB node or a child node receives a path transition configuration for uplink data sent by a network device; and when the IAB-MT completes the handover, the IAB node or the child node applies the path transition configuration.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates to the field of communications. [Background technology]

[0002] Future seamless cellular network deployment requires highly flexible and ultra-dense new radio (NR) cell deployment. Ultra-dense networks are one of the goals of 5G, and the deployment of NR networks that do not require wired backhaul is crucial to achieving such networks. Because 5G millimeter wave technology narrows cell coverage, wireless self-backhaul systems require multi-hop operation to meet deployment needs. 5G's high bandwidth, massive MIMO, and beam systems make it easier to develop wireless self-backhaul systems for ultra-dense NR cells in 5G than in LTE. To develop such multi-hop systems with wireless self-backhaul, 3GPP (registered trademark) initiated research and standardization of the Integrated Access and Backhaul (IAB) project in R16.

[0003] Figure 1 is a schematic diagram of an example of an IAB system. As shown in Figure 1, in the IAB system, access and backhaul adopt NR Uu air interface radio transmission, relay nodes support both access and backhaul functions, and the radio transmission link of the relay node multiplexes the access link and backhaul link in the time domain, frequency domain, or spatial domain, and the access link and backhaul link can use the same frequency band or different frequency bands.

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

[0005] The IAB-node functionality is divided into two parts: the gNB-DU functionality, referred to as the IAB-DU (Distributed Unit), and the UE functionality, referred to as the IAB-MT (Mobile Terminal). The IAB-DU implements the functionality of a network side device and is connected to a downstream child IAB-node (child node). It provides NR air interface access for UEs and downstream child IAB-nodes and establishes an F1 connection with an IAB Donor-CU (Donor Aggregation Unit). The IAB-MT implements part of the functionality of a termination device and is connected to an upstream parent IAB-node (parent node) or IAB-Donor DU. The IAB-MT 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 the IAB system, an IAB-node can access the network in Standalone (SA) mode or Non-Standalone (EN-DC, E-UTRA-NR Dual Connectivity) mode. Figure 2 is a schematic diagram of the IAB architecture in SA mode. Figure 3 is a schematic diagram of the IAB architecture in EN-DC mode.

[0007] Figure 4 is a schematic diagram of an 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 is a schematic diagram of the F1 user plane (F1-U) protocol stack between the IAB-DU and the IAB-Donor CU. Figure 6 is a schematic diagram of 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 the transport (IP) layer between the IAB-DU and the IAB-Donor CU, and Figures 5 and 6 show two-hop wireless backhaul and one-hop wired backhaul.

[0009] In the backhaul link, the transport (IP) layer is carried by the Backhaul Adaptation Protocol (BAP) sublayer, and the BAP entity in the IAB-node realizes the routing function of the IAB system, and the IAB-Donor CU provides the routing table. BAP PDUs (Protocol Data Units) are transmitted over RLC (Radio Link Control) channels of the backhaul link. Multiple RLC channels of the backhaul link may be configured by the IAB-Donor to carry services with different priorities and QoS (Quality of Service), and the BAP entity maps the BAP PDUs to different backhaul RLC channels.

[0010] The above description of the background art is merely for the purpose of explaining the configuration of the present invention more clearly and completely, and is provided for the understanding of those skilled in the art. These configurations described in the background art of the present invention should not be construed as being well known to those skilled in the art. Summary of the Invention [Problem to be solved by the invention]

[0011] According to the discovery of the present inventors, when the network topology changes, if a migrating node changes the donor-DU in the post-migration transmission path, the uplink data of the migrating node cannot be sent to the donor-CU. Furthermore, if the target donor-DU has an IP address filtering function, the uplink data containing the IP address assigned by the source donor-DU will be discarded, resulting in long transmission delays and service interruptions.

[0012] To solve at least one of the above problems, embodiments of the present invention provide an IAB node device, an IAB donor device, and a route transition method. [Means for solving the problem]

[0013] In one aspect of an embodiment of the present invention, a route transition method is provided, the method including: a parent node of an IAB node before migration uses a first donor distribution unit (donor-DU), a parent node of the IAB node after migration uses a second donor distribution unit, and the IAB node or a child node receiving a route transition configuration for uplink data transmitted by a network device before an IAB-MT of the IAB node performs a handover; and a step of the IAB node or a child node applying the route transition configuration when the IAB-MT completes the handover.

[0014] Another aspect of an embodiment of the present invention provides an IAB node device, wherein a parent node of the IAB node before migration uses a first donor distribution unit and a parent node of the IAB node after migration uses a second donor distribution unit, the device including: a receiving unit that receives a route transition configuration for uplink data transmitted by a network device before an IAB-MT of the IAB node performs a handover; and a processing unit that applies the route transition configuration when the IAB-MT completes the handover.

[0015] Another aspect of an embodiment of the present invention provides a route transition method, wherein a parent node of an IAB node before migration uses a first donor distribution unit (donor-DU), a parent node of the IAB node after migration uses a second donor distribution unit, the first donor-DU belongs to a first donor aggregation unit, and the second donor-DU belongs to a second donor aggregation unit, and the first donor aggregation unit (donor-CU) sends a route transition request message to the second donor-CU before sending a handover request for an IAB-MT of the IAB node, and the first donor-CU receives a route transition response message sent by the second donor-CU.

[0016] In another aspect of the embodiment of the present invention, there is provided an IAB donor device, wherein a parent node of an IAB node before migration uses a first donor distribution unit, a parent node of the IAB node after migration uses a second donor distribution unit, the first donor distribution unit belongs to a first donor aggregation unit, and the second donor distribution unit belongs to a second donor aggregation unit; An apparatus is provided, comprising: a transmitter that transmits a path transition request message to the second donor aggregation unit before transmitting a handover request for the IAB-MT of the IAB node; and a receiver that receives a path transition response message transmitted by the second donor aggregation unit.

[0017] Another aspect of an embodiment of the present invention provides an IAB system including an IAB donor device and an IAB node device, wherein a parent node of the IAB node device before migration uses a first donor distribution unit and a parent node of the IAB node device after migration uses a second donor distribution unit, and the IAB node device receives a path migration configuration for uplink data transmitted by a network device before an IAB-MT of the IAB node performs a handover, and applies the path migration configuration when the IAB-MT completes the handover.

[0018] One of the advantageous effects of the embodiment of the present invention is as follows: Before the IAB-MT of an IAB node performs handover, the IAB node or child node receives a path transition configuration for uplink data sent by a network device, and when the IAB-MT completes handover, the IAB node or child node applies the path transition configuration, thereby reducing or avoiding the problem of uplink data being discarded and reducing transmission delay and service interruption time.

[0019] As shown in the following description and drawings, specific embodiments of the present invention are disclosed in detail to illustrate ways in which the principles of the present invention can be employed. However, the scope of the present invention is not limited to these embodiments. The present invention encompasses all modifications, alterations, and equivalents within the spirit and scope of the appended claims.

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

[0021] It should be noted that in this text, the term "comprise / have" means the presence of a feature, element, step or component, and does not exclude the presence or addition of one or more other features, elements, steps or components. [Brief explanation of the drawings]

[0022] Elements and features depicted in one drawing and one embodiment of an example of the invention may be combined with elements and features shown in one or more drawings or embodiments, and in the drawings, like reference numerals may indicate corresponding elements in multiple drawings and may indicate corresponding elements used in more than one embodiment.

[0023] The drawings included are used to further understand the embodiments of the present invention, constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the written description, explain the principles of the present invention. Note that the drawings described below are merely some examples of the present invention, and those skilled in the art can easily imagine other drawings based on these drawings. [Figure 1] FIG. 1 is a schematic diagram of an example IAB system. [Figure 2] FIG. 1 is a schematic diagram of an example of an IAB architecture in SA mode. [Figure 3] FIG. 1 is a schematic diagram of an example of an IAB architecture in EN-DC mode. [Figure 4] FIG. 1 is a schematic diagram of an example of a parent IAB-node and a child IAB-node. [Figure 5] FIG. 1 is a schematic diagram of an example of an F1-U protocol stack in an IAB system. [Figure 6] FIG. 1 is a schematic diagram of an example of an F1-C protocol stack in an IAB system. [Figure 7] FIG. 1 is a schematic diagram of an example of system routing. [Figure 8] FIG. 1 is a schematic diagram of an example of a route transition. [Figure 9] FIG. 2 is a schematic diagram of an example of a route transition according to an embodiment of the present invention. [Figure 10] FIG. 2 is a schematic diagram of an example of a route transition method according to an embodiment of the present invention. [Figure 11] FIG. 2 is a schematic diagram of an example of a route transition according to an embodiment of the present invention. [Figure 12]FIG. 10 is a diagram illustrating an example of a signaling flow for a route transition according to an embodiment of the present invention. [Figure 13] FIG. 10 is a schematic diagram of another example of a route transition according to an embodiment of the present invention. [Figure 14] FIG. 10 is a schematic diagram of another example of a route transition according to an embodiment of the present invention. [Figure 15] FIG. 10 is a diagram illustrating another example of a signaling flow for a route transition according to an embodiment of the present invention. [Figure 16] FIG. 2 is a schematic diagram of an example of an IAB node device according to an embodiment of the present invention. [Figure 17] 1 is a schematic diagram of an example of an IAB donor device according to an embodiment of the present invention. [Figure 18] 1 is a schematic diagram of an example of an IAB device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] These and other features of the present invention will become apparent from the following description. In the specification and drawings, specific embodiments of the present invention are disclosed in detail, and some of the embodiments in which the principles of the present invention can be employed are shown. However, the present invention is not limited to the described embodiments. The present invention includes all modifications, variations, and equivalents within the scope of the appended claims.

[0025] In embodiments of the present invention, the terms "first," "second," etc. are used in titles to distinguish between different elements, but do not represent the spatial arrangement or temporal order of these elements, and these elements are not limited to these terms. The term "and / or" includes any and all combinations of one or more of the terms listed in the associated list. The terms "comprise," "include," "have," etc. refer to the presence of listed features, elements, elements, or components, but do not exclude the presence or addition of one or more other features, elements, elements, or components.

[0026] In the embodiments of the present invention, the singular forms "one," "the," etc., include the plural and should be understood broadly as "one kind" or "one class," and are not limited to "one." Furthermore, the term "said" should be understood to include both the singular and the plural, unless the context clearly indicates otherwise. Furthermore, the term "according to" should be understood as "according at least in part to" and the term "based on" should be understood as "based at least in part on." unless the context clearly indicates otherwise.

[0027] 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 radio (NR), Long Term Evolution (LTE), Long Term Evolution-Advanced (LTE-A, LTE-Advanced), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), etc.

[0028] Additionally, communications between devices in a communications system may occur according to any stage of communications protocol, including, but not limited to, 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G, and future 5G, 6G, etc., and / or other currently known communications protocols or other communications protocols developed in the future.

[0029] In an embodiment of the present invention, the term "network device" refers to a device in a communication system that allows a terminal device to access the communication system and provides a service to the terminal device, and may include, but is not limited to, a base station (BS), an access point (AP), a transmission reception point (TRP), a broadcast transmitter, a mobility management entity (MME), a gateway, a server, a radio network controller (RNC), a base station controller (BSC), etc.

[0030] Here, the base station may include, but is not limited to, a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), a 5G base station (gNB), etc., as well as a remote radio head (RRH), a remote radio unit (RRU), a relay, or a low-power node (e.g., femto, pico, etc.). Also, the term "base station" may include some or all of these functions, and each base station may provide communication coverage for a particular geographic area. The term "cell" may refer to a base station and / or its coverage area, depending on the context in which the term is used.

[0031] In the embodiments of the present invention, the term "User Equipment" (UE) or "Terminal Equipment" (TE) refers to a device that accesses a communication network and receives network services via, for example, a network device. The terminal device may be fixed or mobile, and may also be referred to as a mobile station (MS), a terminal, a subscriber station (SS), an access terminal (AT), a station, etc.

[0032] Here, the terminal device may include, but is not limited to, a cellular phone, a personal digital assistant (PDA), a wireless modulation / demodulation device, a wireless communication device, a handheld device, a machine-type communication device, a laptop computer, a cordless phone, a smartphone, a smart watch, a digital camera, and the like.

[0033] For example, in a scenario such as the Internet of Things (IoT), the user equipment may be a monitoring or measuring device or apparatus, including, but not limited to, a Machine Type Communication (MTC) terminal, an in-vehicle communication terminal, a Device to Device (D2D) terminal, a Machine to Machine (M2M) terminal, etc.

[0034] The routing function of the IAB system is realized by the BAP layer, and each IAB-node stores a routing configuration (BH routing configuration) and an RLC channel mapping configuration (BH RLC Channel Mapping Configuration). The BAP entity performs routing based on the routing configuration, the RLC channel mapping configuration, and the routing identifier (Routing ID) in the packet header of the BAP layer. The Routing ID includes the destination BAP address and a path identifier.

[0035] The routing configuration includes a mapping relationship between a Routing ID and a BAP address of a next-hop node. The RLC channel map configuration includes a mapping relationship between a BAP address of a previous hop node, an ingress RLC channel ID, a BAP address of a next-hop node, and an egress RLC channel ID.

[0036] FIG. 7 is a schematic diagram of an example of system routing. As shown in FIG. 7, for each packet, the BAP address of the immediately succeeding hop node can be retrieved from the routing configuration using the Routing ID in the packet header. The BAP address of the immediately preceding hop node and the ingress link RLC channel ID are known. Once the BAP address of the immediately succeeding hop node is determined in this manner, the egress link RLC channel ID can be retrieved using the RLC channel mapping configuration based on the BAP address of the immediately preceding hop node + ingress link RLC channel ID + BAP address of the immediately succeeding hop node.

[0037] The IAB-donor DU stores the routing configuration (BH routing configuration) and the downlink RLC channel mapping configuration (Downlink Traffic to BH RLC Channel Mapping Configuration). The IAB-donor DU performs routing based on the routing configuration, the RLC channel mapping configuration, and the Routing ID in the packet header of the BAP layer. The routing configuration includes a mapping relationship between the Routing ID and the address of the next hop node. The downlink RLC channel mapping configuration includes a mapping relationship between the target IP address, the DSCP (Differentiated Services Code Point), the address of the next hop node, and the egress link RLC channel ID.

[0038] For each downlink stream packet arriving at the IAB-donor DU, the IAB-donor DU can look up the address of the next hop node from the routing configuration based on the Routing ID in the packet header. Once the address of the next hop node is determined in this way, it looks up the egress link RLC channel ID from the downlink RLC channel mapping configuration based on the packet's IP address and DSCP.

[0039] The above is an exemplary explanation of routing in the IAB system, but the following describes network topology updates in the IAB system. Rel-16 NR standardizes the network topology adaptation process when an IAB-node moves under the same donor-CU.

[0040] 8 is a schematic diagram of an example of intra-CU path transition (also called topology adaptation). When an IAB-node changes its parent node (from IAB-node 1 to IAB-node 2), the donor-CU configures the path transition for the IAB-node via an RRC reconfiguration message, causing the IAB-node to transition its F1 transmission path.

[0041] The configurations related to network topology updates include updating the default backhaul RLC channel for uplink F1-C, F1-U, and non-F1 data, updating the default BH RLC channel, updating the default BAP routing ID, and updating the IP address routed to the Donor-DU. When the IAB-node accesses a new parent node, it starts applying the above configurations related to route transition, and the child nodes of the IAB-node also undergo the configurations related to network topology updates in a similar manner.

[0042] According to the discovery of the inventors of the present invention, the path migration of the uplink service of the transition node and the path migration of the uplink service of the child node are performed after the transition node completes random access to the target parent node, resulting in long transmission delays and service interruptions.

[0043] 9 is a schematic diagram of an example of a path transition according to an embodiment of the present invention. As shown in FIG. 9, when the transmission path of the IAB node after handover changes to a donor-DU (from donor-DU 1 to donor-DU 2), uplink data generated by the IAB node F1-U and child nodes based on the original path configuration cannot be transmitted to the CU. This is because the uplink data generated based on the original path configuration carries the BAP address of the source donor-DU, which is different from the BAP address of the target donor-DU. Therefore, the target donor-DU discards the uplink data. Furthermore, if the target donor-DU has an IP address filtering function, the uplink data containing the IP address assigned by the source donor-DU is also discarded. The discarded uplink data must be retransmitted by the UE, resulting in a long transmission delay and service interruption.

[0044] In view of at least one of the above-mentioned problems or similar problems, in an embodiment of the present invention, before an IAB node performs a handover, the IAB node or a child node receives a path transition configuration for uplink data transmitted by a network device. The following is a detailed description. In the embodiment of the present invention, unless otherwise specified, the transition node is an IAB node, and the IAB node device includes an IAB node or a child node.

[0045] Example 1 An embodiment of the present invention provides a path migration method, which is described from the perspective of an IAB node or a child node. Here, the parent node of the IAB node before migration uses a first donor distribution unit (source donor-DU), and the parent node after migration uses a second donor distribution unit (target donor-DU), which can be abbreviated as the IAB node migrating from the first donor-DU to the second donor-DU. In some scenarios, the IAB node uses the first donor-DU before migration and the second donor-DU after migration, i.e., the parent node of the IAB node is the first donor-DU or the second donor-DU.

[0046] 10 is a schematic diagram of an example of a route transition method according to an embodiment of the present invention. As shown in FIG. 10, the method includes the following steps:

[0047] Step 1001: Before an IAB-MT of an IAB node performs a handover, the IAB node or a child node receives a path transition configuration of uplink data sent by a network device.

[0048] Step 1002: When the IAB-MT completes the handover, the IAB node or the child node applies the path transition configuration.

[0049] It should be noted that the above-mentioned Figure 10 merely illustrates an example of the present invention, and the present invention is not limited thereto. For example, the execution order of various steps may be appropriately adjusted, some other steps may be added, or some steps may be removed. Those skilled in the art can make appropriate modifications based on the above content, and are not limited to the description of the above-mentioned Figure 10.

[0050] For example, before the IAB-MT of the migrating node performs handover, the donor-CU configures the path transition parameters of the uplink F1 and non-F1 services of the migrating node and the uplink F1 and non-F1 services of the child node. After the IAB-MT completes the handover, the migrating node or the child node immediately applies these path transition parameters. This can avoid uplink data loss and service interruption.

[0051] The following further describes embodiments of the present invention with reference to the transmission of uplink data in various scenarios.

[0052] In some embodiments, the first donor distribution unit (donor-DU) and the second donor distribution unit belong to the same donor aggregation unit (donor-CU), and the path transition configuration is sent by the donor-CU to the IAB node or child node via an F1AP message or a radio resource control (RRC) message.

[0053] In some embodiments, the transition node has a routing ID rewrite function.

[0054] The route transition configuration includes adding an inter-donor distributed unit routing identifier rewrite configuration to indicate a mapping relationship between a first routing identifier and a second routing identifier, adding a routing configuration including a mapping relationship between the second routing identifier and a BAP address of a immediately subsequent hop node of the IAB node, and adding an RLC channel mapping configuration to indicate a mapping relationship between the BAP address of the immediately subsequent hop node of the IAB node, an ingress link Radio Link Control (RLC) channel identifier, a BAP address of the immediately subsequent hop node of the IAB node, and an egress link RLC channel identifier, where the destination BAP address of the first routing identifier is the BAP address of the first donor-DU and the destination BAP address of the second routing identifier is the BAP address of the second donor-DU.

[0055] For example, the network device that transmits the route transition configuration is a donor-CU. The donor inter-distribution unit routing identifier rewriting configuration for indicating a mapping relationship between a first routing identifier and a second routing identifier is specifically mapping relationship information between a routing ID before rewriting and a routing ID after rewriting (inter-donor-DU rewriting information). The routing configuration for indicating a mapping relationship between the second routing identifier and a BAP address of a immediately subsequent hop node of an IAB node is specifically routing information. The RLC channel mapping configuration for indicating a mapping relationship between a BAP address of an immediately subsequent hop node of an IAB node and an ingress link Radio Link Control (RLC) channel ID, and between a BAP address of a immediately subsequent hop node of an IAB node and an egress link RLC channel ID is specifically RLC channel mapping information.

[0056] For example, the donor-CU configures three pieces of information, namely, inter-donor-DU rewriting information (mapping relationship information between pre-rewrite routing IDs and post-rewrite routing IDs), routing information, and RLC channel mapping information, in the transition node before the transition node's IAB-MT executes handover. These three pieces of information may be configured in the IAB node collectively via the same message, or may be configured in the IAB node individually via two or more messages, but the present invention is not limited thereto.

[0057] 11 is a schematic diagram of an example of a path transition according to an embodiment of the present invention. As shown in FIG. 11, IAB node 3 (including IAB-MT 3 and IAB-DU 3) is a transition node, and its transmission path transitions from donor-DU 1 to donor-DU 2. After the handover of IAB-MT 3 of IAB node 3 is completed, the service may be maintained with the routing IDs in IAB node 3 and child nodes (e.g., IAB node 4 and IAB node 5 shown in the figure) remaining unchanged, as indicated by the solid lines in the right part.

[0058] In some embodiments, the IAB node may rewrite the first routing identifier carried in the BAP header of the uplink data to the second routing identifier because the IAB node received the donor-distributed-unit inter-routing identifier rewriting configuration (e.g., inter-donor-DU rewriting information) sent by the network device.

[0059] For example, as shown by the dashed line in the right part of Fig. 11, IAB node 3 needs to replace the original routing IDs of its uplink services and the uplink services of its child nodes (such as IAB node 4 and IAB node 5 shown in the figure) with new routing IDs, where the destination BAP address of the original routing ID is the source donor-DU, and the destination BAP address of the new routing ID after replacement is the target donor-DU.

[0060] Also, for example, after the original routing ID is replaced with a new routing ID, the donor-CU may perform routing and BH RLC channel selection according to the new routing ID, and update the routing configuration (because the original routing table does not contain any routing available for the new routing ID) and RLC channel mapping table in the transition node.

[0061] In an embodiment of the present invention, the new routing ID may be referred to as the target routing ID or the replaced (rewritten) routing ID, and these terms may be interchangeable. The original routing ID may be referred to as the source routing ID or the old routing ID or the replaced (rewritten) routing ID, and these terms may be interchangeable.

[0062] The transition node may apply the inter-donor-DU rewriting information, new routing table, and RLC channel mapping table when the handover is completed or when the configuration is received. The donor-CU may instruct the transition node to buffer the above path transition configuration first and apply the above path transition configuration when the IAB-MT completes the handover.

[0063] The above explains the case of routing ID, but below we will explain the case of IP address.

[0064] In some embodiments, the IAB node receives first configuration information sent by the donor-CU before performing the handover, where the first configuration information is used to configure the IAB node to replace an IP address anchored to the first donor-DU with an IP address anchored to the second donor-DU, where the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node.

[0065] For example, if the target donor-DU has a source IP address filtering function, i.e., discards uplink data containing IP addresses assigned by other donor-DUs, the transition node needs to change the IP address carried by the uplink service to the IP address assigned by the target donor-DU. Therefore, the donor-CU configures the IP address assigned by the target donor-DU in the transition node before the transition node performs handover.

[0066] In an embodiment of the present invention, an "IP address anchored to IAB donor-DU" may be understood as an "IP address assigned by the donor-DU" or a "Transport Network Layer (TNL) address(es) that is(are) routable via the IAB-donor-DU", and the above terms may be interchangeable, but the present invention is not limited thereto.

[0067] If the transition node has a routing identifier rewrite function, the routing ID of the service (including the uplink service and the downlink service) may remain unchanged in the transition node and the child node, but the IP address anchored to the first donor-DU needs to be replaced with the IP address anchored to the second donor-DU. Meanwhile, since the IAB node selects the IP address to use according to the first donor-DU, the configuration of the IP address of the service needs to correspond to the BAP address of the first donor-DU, and includes adding the IP address anchored to the second donor-DU and releasing the IP address anchored to the first donor-DU.

[0068] In some embodiments, the first configuration information is IP address configuration information corresponding to the BAP address of the first donor-DU. For example, the first configuration information is used to change the IP address anchored to the first donor-DU, which corresponds to the BAP address of the first donor-DU, to an IP address anchored to the second donor-DU.

[0069] In some embodiments, the IAB node replaces the IP address anchored to the first donor-DU with the IP address anchored to the second donor-DU when the random access of the handover is completed.

[0070] For example, the transition node needs to immediately apply the IP address assigned by the target donor-DU once the handover is complete. Also, for example, the above "replacement" may be understood as "adding an IP address anchored to the second donor-DU and releasing an IP address anchored to the first donor-DU."

[0071] In some embodiments, the child node or the parent node of the child node receives first configuration information sent by the donor-CU before the IAB node performs the handover, where the first configuration information is used to configure the first donor-DU to replace an IP address anchored to the first donor-DU with an IP address anchored to the second donor-DU, where the IP address is used for the child node's F1 user plane data, F1 control plane data, or non-F1 data.

[0072] For example, the child node needs to change the IP address carried by uplink F1 and non-F1 data (e.g., OAM data) to the IP address assigned by the target donor-DU. Therefore, the donor-CU needs to configure the IP address assigned by the target donor-DU for F1 and non-F1 data into the child node or the child node's parent node before the transition node performs handover.

[0073] In some embodiments, the child node replaces the IP address anchored to the first donor-DU with the IP address anchored to the second donor-DU when the IAB node completes the random access of the handover.

[0074] For example, when the transition node completes the handover, the child node needs to immediately apply the IP address assigned by the target donor-DU. Also, for example, the above "replace" may be interpreted as "adding an IP address anchored to the second donor-DU and releasing an IP address anchored to the first donor-DU."

[0075] In some embodiments, the first configuration information is transmitted by the donor aggregation unit to the IAB node via a handover command Radio Resource Control (RRC) message or an RRC reconfiguration message, for example, the first configuration information is transmitted by the donor aggregation unit to the child node or a parent node of the child node via an RRC reconfiguration message.

[0076] In some embodiments, once the handover is complete, the transition node may send an instruction to the child node to cause the child node to apply the IP address configuration, so that the child node immediately applies the IP address when the transition node completes the handover. Alternatively, the IP address configured for the child node may be buffered by the child node's parent node before the handover is complete until it is sent to the child node when the transition node completes the handover.

[0077] FIG. 12 is a diagram illustrating an example of a signaling flow for a route transition according to an embodiment of the present invention, showing an example of a signaling flow when an IAB node performs a route transition between different donor-DUs of the same donor-CU.

[0078] As shown in FIG. 12, before preparing for handover, the donor-CU initiates a route transition for the transition node.

[0079] The transition node sends a measurement report to the donor-CU, triggering the donor-CU to initiate route transition.

[0080] The donor-CU configures the migration node and child node's uplink services to replace the destination BAP address of the original routing ID with the new routing ID of the target donor-DU. The donor-CU requests from the destination donor-DU the IP address to be used for the migration node's F1 service or non-F1 service and the IP address to be used for the child node's F1 service or non-F1 service.

[0081] The donor-CU generates inter-donor-DU rewriting information based on the original routing ID and the new routing ID after replacement, generates routing information for the new routing ID after replacement, and configures the egress link BH RLC channel identifier from the migration node to the target parent node based on the QoS of the uplink service.

[0082] The donor CU uses an F1AP message (e.g., BAP MAPPING CONFIGURATION) to transmit configuration information to the transition node, i.e., inter-donor-DU rewriting information, routing information for the new routing ID after replacement, and the egress link BH RLC channel identifier from the transition node to the target parent node.

[0083] The donor-CU sends an RRC reconfiguration message (including the IP address allocated by the target donor-DU for F1 or non-F1 services) to the transition node, or configures the IP address allocated by the target donor-DU in the transition node via a handover command RRC message.

[0084] The donor-CU sends an RRC reconfiguration message (including the IP addresses allocated by the target donor-DU for F1 and non-F1 services) to the child node.

[0085] The donor-CU updates routing information and RLC channel mapping information for nodes on the target path.

[0086] The donor-CU initiates the handover for the transition node.

[0087] Once the transition node completes the handover, it applies the IP addresses for the above configured F1 or non-F1 services.

[0088] Once the transition node completes the handover, the child node applies the IP addresses for the above configured F1 or non-F1 services.

[0089] The above signaling process is merely a rough description of an embodiment of the present invention, and the present invention is not limited thereto. For specific details of the signaling, reference may be made to related art.

[0090] The above has been a brief description of the case where the transition node has a routing ID rewrite function, but the following will describe the case where the transition node does not have a routing ID rewrite function.

[0091] In some embodiments, the transition node does not have routing ID rewriting functionality, or the transition node is not configured with inter-donor-DU rewriting information.

[0092] The route transition configuration includes adding a routing configuration including a mapping relationship between a second routing identifier and a BAP address of a immediately subsequent hop node of the IAB node, and adding a radio link control channel mapping configuration to indicate a mapping relationship between the BAP address of the immediately subsequent hop node of the IAB node, an ingress link RLC channel identifier, a BAP address of the immediately subsequent hop node of the IAB node, and an egress link RLC channel identifier, where the destination BAP address of the second routing identifier is the BAP address of the second donor-DU.

[0093] For example, the network device that transmits the route transition configuration is a donor-CU. The routing configuration including the mapping relationship between the second routing identifier and the BAP address of the immediately preceding hop node of the IAB node is specifically routing information. The RLC channel mapping configuration for indicating the mapping relationship between the BAP address of the immediately preceding hop node of the IAB node and an ingress link Radio Link Control (RLC) channel identifier, and between the BAP address of the immediately preceding hop node of the IAB node and an egress link RLC channel identifier is specifically RLC channel mapping information.

[0094] For example, before the IAB-MT of the transition node performs handover, the donor-CU configures two pieces of information, routing information and RLC channel mapping information, in the transition node. These two pieces of information may be configured in the IAB node together via the same message, or may be configured in the IAB node separately via two or more messages, but the present invention is not limited thereto.

[0095] In some embodiments, the IAB node receives second configuration information sent by the donor-CU before performing the handover to configure a second routing identifier, where the second routing identifier is used for the IAB node's uplink F1 user plane data, F1 control plane data, or non-F1 data.

[0096] In some embodiments, the child node or the parent node of the child node receives second configuration information sent by the donor-CU before the IAB node performs the handover, for configuring a second routing identifier, where the second routing identifier is used for the child node's uplink F1 user plane data, F1 control plane data, or non-F1 data.

[0097] 13 is a schematic diagram of another example of path transition according to an embodiment of the present invention. As shown in FIG. 13, IAB node 3 (including IAB-MT 3 and IAB-DU 3) is a transition node, and its transmission path transitions from donor-DU 1 to donor-DU 2. As indicated by the dashed line in the right part, when IAB-MT 3 of IAB node 3 completes handover, both the routing IDs in IAB node 3 and child nodes of the service (e.g., IAB node 4 and IAB node 5 shown in the figure) need to be updated.

[0098] For example, IAB node 3 needs to update the routing IDs of uplink F1 and non-F1 services, and child nodes (such as IAB node 4 and IAB node 5 shown in FIG. 13) need to update the routing IDs of uplink F1 and non-F1 services. Therefore, donor-CU needs to configure the target routing IDs of the uplink F1 and non-F1 services of the transition node and the target routing IDs of the uplink F1 and non-F1 services of the child node in the transition node and the child node, respectively, before the transition node performs handover.

[0099] In some embodiments, the IAB node applies the second routing identifier when completing random access for the handover. The IAB node applies the second routing identifier when completing random access for the handover. For example, the transition node and the child node should immediately apply the configured target routing ID when the transition node completes the handover.

[0100] Also, for example, the IAB node updates the routing ID of the uplink data, and then performs routing selection and backhaul RLC channel selection according to the target routing ID. The donor-CU updates the routing information and RLC channel mapping information in the transition node and the child node, and configures them before the transition node performs handover (because the original routing information does not include available routing for the target routing ID).

[0101] The transition node and child node may immediately apply the new routing information and / or RLC channel mapping information upon completion of handover or upon receiving the configuration. The Donor-CU may instruct the transition node and child node to buffer the above path transition configuration and apply it upon completion of handover.

[0102] The above explains the case of routing ID, but below we will explain the case of IP address.

[0103] In some embodiments, the IAB node receives third configuration information sent by the donor-CU before the IAB-MT performs the handover, where the third configuration information is used to configure an IP address anchored to the second Donor-DU.

[0104] For example, if the target donor-DU has a source IP address filtering function, the transition node needs to change the IP address carried by the uplink service to the IP address assigned by the target donor-DU. Therefore, before the transition node performs the handover, the donor-CU needs to configure the IP address assigned by the target donor-DU in the transition node. The transition node needs to apply the IP address assigned by the target donor-DU upon completion of the handover or upon receiving a configuration message.

[0105] In some embodiments, the third configuration information includes configuration information for adding an IP address anchored to the second donor-DU for the BAP address of the second donor-DU.

[0106] In some embodiments, the child node receives third configuration information sent by the donor-CU before the IAB-MT performs the handover, where the third configuration information is used to configure an IP address anchored to the second donor-DU.

[0107] For example, the child node needs to change the IP address carried by uplink F1 and non-F1 data (e.g., OAM data) to the IP address assigned by the target donor-DU. Therefore, the donor-CU needs to configure the child node with the IP address assigned by the target donor-DU before the transition node performs the handover. The child node needs to apply the IP address assigned by the target donor-DU when the transition node completes the handover or receives a configuration message.

[0108] In some embodiments, the third configuration information of the IAB node is transmitted by the donor aggregation unit via a handover command radio resource control (RRC) message or an RRC reconfiguration message. The third configuration information of the IAB node is transmitted by the donor aggregation unit via an RRC reconfiguration message.

[0109] The above has been described as an example of the case where the same CU is used, but the following will describe the case where different CUs are used.

[0110] In some embodiments, the first donor-DU belongs to a first donor aggregation unit and the second donor-DU belongs to a second donor aggregation unit, and the path transition configuration is sent by the first donor aggregation unit to the IAB node or child node via an F1AP message or an RRC message, where the IAB-DU of the IAB node maintains an F1 connection with the first donor aggregation unit.

[0111] In some embodiments, the path transition configuration includes adding an inter-donor aggregation unit routing identifier rewrite configuration to indicate a mapping relationship between the first routing identifier and the second routing identifier, adding a routing configuration including a mapping relationship between the second routing identifier and a BAP address of a immediately subsequent hop node of the IAB node, and adding an RLC channel mapping configuration to indicate a mapping relationship between a BAP address of a immediately subsequent hop node of the IAB node and an ingress link RLC channel identifier, and a BAP address of a immediately subsequent hop node of the IAB node and an egress link RLC channel identifier.

[0112] Here, the first routing identifier and the BAP address of the IAB node's immediately preceding hop node belong to the network topology domain of the first donor aggregation unit, the destination BAP address of the first routing identifier is the BAP address of the first donor-DU, the second routing identifier and the BAP address of the IAB node's immediately following hop node belong to the network topology domain of the second donor aggregation unit, and the destination BAP address of the second routing identifier is the BAP address of the second donor-DU.

[0113] For example, after a transition node switches from a parent node under the source donor-CU to a parent node under the destination donor-CU, only the RRC connection is switched to the target donor-CU, the F1 interface still belongs to the source donor-CU, and the RRC connections of its serving child nodes and UEs still belong to the source donor-CU; in this case, the transition node is also referred to as a boundary node.

[0114] The routing ID of the boundary node's F1 or non-F1 data and the routing ID of the child node's F1 or non-F1 data may be kept unchanged, but the boundary node must replace the original routing ID of the uplink service with the target routing ID.

[0115] Here, the original routing ID belongs to the topology domain of the source donor-CU and its destination BAP address is the source donor-DU, while the new routing ID after replacement belongs to the topology domain of the target donor-CU and its destination BAP address is the target donor-DU. Therefore, before the boundary node performs handover, the network device needs to configure mapping relationship information (BAP Header Rewriting information) between the original routing ID and the new routing ID in the boundary node.

[0116] Also, for example, when the boundary node forwards uplink data, it replaces the original routing ID with a new routing ID, and since the new routing ID belongs to the topological domain of the target donor-CU, the boundary node must make a routing selection based on the new routing ID and the routing information of the topological domain of the target donor-CU. Therefore, the network device must configure, in the boundary node, routing information in which the BAP address of the next hop after the egress link belongs to the topological domain of the target donor-CU (the BAP address of the next hop after the egress link in the original routing information belongs to the topological domain of the original donor-CU).

[0117] Also, for example, since the BAP address of the previous hop node of the boundary node belongs to the topology domain of the source donor-CU, and the BAP address of the next hop node belongs to the topology domain of the target donor-CU, the network device needs to update the RLC channel mapping information at the boundary node (both the address of the previous hop node and the address of the next hop node in the original RLC channel mapping information belong to the topology domain of the original donor-CU).

[0118] 14 is a schematic diagram of another example of path transition according to an embodiment of the present invention. As shown in FIG. 14, IAB node 3 (including IAB-MT 3 and IAB-DU 3) is a transition node, and its transmission path transitions from donor-DU 1 of a source donor-CU to donor-DU 2 of a target donor-CU. As shown by the solid line in the right part, when IAB-MT 3 of IAB node 3 completes handover, the routing IDs of the uplink service of IAB node 3 and the uplink services of child nodes (e.g., IAB node 4 and IAB node 5 shown in the figure) may remain unchanged.

[0119] In some embodiments, the IAB node may rewrite the first routing identifier carried in the BAP header of the uplink data to the second routing identifier because the IAB node receives the mapping relationship information (inter-donor-CU rewriting information) sent by the network device.

[0120] For example, as shown by the dashed line in the right part of Fig. 14, IAB node 3 needs to replace the original routing IDs of the uplink services and the uplink services of child nodes (such as IAB node 4 and IAB node 5 shown in the figure) with new routing IDs, where 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 new routing ID after replacement is donor-DU 2 of the target donor-CU.

[0121] Also, for example, after the original routing ID is replaced with a new routing ID, routing selection and backhaul RLC channel selection may be performed according to the new routing ID. The donor-CU needs to update the routing information (because the original routing information does not include available routing for the target routing ID) and RLC channel mapping information in the transition node.

[0122] The transition node may apply the inter-donor-CU rewriting information, new routing information, and RLC channel mapping information upon completion of handover or upon receiving the configuration. The donor-CU may instruct the transition node to buffer the above path transition configuration first and apply it when the IAB-MT completes handover.

[0123] The above explains the case of routing ID, but below we will explain the case of IP address.

[0124] In some embodiments, the IAB node receives first configuration information sent by the first donor-CU before performing the handover, where the first configuration information is used to configure the IAB node to replace an IP address anchored to the first donor-DU with an IP address anchored to the second donor-DU, where the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node.

[0125] For example, if the target donor-DU has a source IP address filtering function, i.e., discards uplink data containing IP addresses assigned by other donor-DUs, the transition node needs to change the IP address carried by the uplink data to the IP address assigned by the target donor-DU. Therefore, the donor-CU configures the IP address assigned by the target donor-DU in the transition node before the transition node performs handover.

[0126] In an embodiment of the present invention, an "IP address anchored to IAB donor-DU" may be understood as an "IP address assigned by the donor-DU" or a "Transport Network Layer (TNL) address(es) that is(are) routable via the IAB-donor-DU", and the above terms may be interchangeable, but the present invention is not limited thereto.

[0127] The routing IDs of services (including uplink services and downlink services) may be maintained unchanged in the transition node and child node, but the IP addresses anchored to the first Donor-DU need to be replaced with IP addresses anchored to the second Donor-DU. Because the IAB node selects the IP addresses to use according to the first Donor-DU, the configuration of the IP addresses of the services needs to be for the BAP address of the first Donor-DU, and includes adding the IP addresses anchored to the second donor-DU and releasing the IP addresses anchored to the first donor-DU.

[0128] In some embodiments, the first configuration information is IP address configuration information for the BAP address of the first donor-DU, for example, the first configuration information is used to change the IP address anchored to the first donor-DU for the BAP address of the first donor-DU to an IP address anchored to the second donor-DU.

[0129] In some embodiments, the IAB node replaces the IP address anchored to the first donor-DU with the IP address anchored to the second donor-DU upon completing the random access of the handover.

[0130] For example, the transition node needs to immediately apply the IP address assigned by the target donor-DU upon completing the handover. Also, for example, the above "replacement" may be understood as "adding an IP address anchored to the second donor-DU and releasing an IP address anchored to the first donor-DU."

[0131] In some embodiments, the child node or the parent node of the child node receives first configuration information sent by the first donor-CU before the IAB node performs the handover, where the first configuration information is used to configure the first donor-DU to replace an IP address anchored to the first donor-DU with an IP address anchored to the second donor-DU, where the IP address is used for the child node's F1 user plane data, F1 control plane data, or non-F1 data.

[0132] For example, the child node needs to change the IP address carried by uplink F1 and non-F1 data (e.g., OAM data) to the IP address assigned by the target donor-DU. Therefore, the donor-CU needs to configure the IP address assigned by the target donor-DU for F1 and non-F1 data to the child node or the child node's parent node before the transition node performs handover.

[0133] In some embodiments, the child node replaces the IP address anchored to the first donor-DU with the IP address anchored to the second donor-DU once the IAB node completes the random access of the handover.

[0134] For example, when the transition node completes the handover, the child node needs to immediately apply the IP address assigned by the target donor-DU. Also, for example, the above "replacement" may be understood as "adding an IP address anchored to the second donor-DU and releasing an IP address anchored to the first donor-DU."

[0135] In some embodiments, the first configuration information is transmitted by the donor aggregation unit to the IAB node via a handover command Radio Resource Control (RRC) message or an RRC reconfiguration message. The first configuration information is transmitted by the donor aggregation unit to the child node or a parent node of the child node via an RRC reconfiguration message.

[0136] In some embodiments, to cause the child node to immediately apply the above IP address configuration when the transition node completes the handover, the transition node may send an instruction to the child node to cause the child node to apply the above IP address configuration. The IP address configured for the child node is buffered by the child node's parent node before the handover is complete until it is sent to the child node when the transition node completes the handover.

[0137] It should be noted that in some other embodiments, the IAB node or child node may receive the above-mentioned first configuration information after the IAB-MT performs handover, and embodiments of the present invention are not limited to the first configuration information being received before or after handover of the IAB node.

[0138] The method of an IAB node or a child node receiving the above-mentioned first configuration information may also be applied to a scenario in which a part of the transmission path of a service is migrated to the network topology domain of a second donor-CU when the IAB-MT of the IAB node maintains dual connectivity with the first donor-CU and the first donor-CU, and a scenario in which the entire transmission path of a service is migrated to the network topology domain of the second donor-CU when the IAB-MT of the IAB node is re-established in the second donor-CU, where the parent node before the service path migration uses the first donor-DU and the parent node after the migration uses the second donor-DU, and the first configuration information is used to configure the IP address anchored to the first donor-DU to be replaced with an IP address anchored to the second donor-DU for the migrated service.

[0139] FIG. 15 is a diagram showing another example of a signaling flow for a route change according to an embodiment of the present invention, and shows an example of a signaling flow when an IAB node performs a route change between different donor-CUs.

[0140] As shown in FIG. 15, before handover preparation, the source donor-CU initiates route transition for the transition node.

[0141] The transition node sends a measurement report to the source donor-CU, triggering the source donor-CU to start path transition.

[0142] The source donor-CU sends a route transition request Xn message to the destination donor-CU.

[0143] The route transition request includes the following:

[0144] Each uplink service flow requiring a migration node includes QoS information, the routing ID used in the topology domain of the source donor-CU (the routing ID before being replaced by the migration node), and the ingress link BH RLC channel ID of the migration node to be used.

[0145] Each uplink service flow requiring migration of each child node includes QoS information, the routing ID used in the topology domain of the source donor-CU (the routing ID before being replaced by the migration node), and the ingress BH RLC channel ID of the migration node used.

[0146] ··For the transition node, the source donor-CU may request allocation of IP addresses for F1 and non-F1 services, and instruct the target donor-CU to include the IP addresses allocated for the transition node's services in the transition node's handover command RRC message.

[0147] ··For child nodes, request IP address allocation for F1 and non-F1 services.

[0148] The destination donor-CU configures the uplink services of the transition node and child node with the target routing ID in the topology domain of the target donor-CU and the egress link BH RLC channel ID from the transition node to the target parent node. The target donor-CU requests the IP addresses that the target donor-DU will use for the transition node's services and the child node's services.

[0149] The target donor-CU sends a path transition response Xn message to the source donor-CU, which contains:

[0150] Each uplink service flow of the transition node includes the target routing ID (replaced routing ID) used in the topology domain of the target donor-CU, and the egress link BH RLC channel identifier of the transition node used.

[0151] Each uplink service flow of the child node includes the target routing ID (replaced routing ID) used in the topology domain of the target donor-CU and the egress link BH RLC channel identifier of the transition node used.

[0152] The routing information of the target donor-CU domain includes the BAP address of the next hop corresponding to the replaced target routing ID.

[0153] For the migrating node, include the IP address allocated by the target donor-DU (included in the RRC reconfiguration message). Here, the IP address used for the migrating node service may not be included in the route migration response Xn message, but may be included in a subsequent Handover Request Ack message.

[0154] ··For the child node, includes the IP address (contained in the RRC message) assigned by the target donor-DU.

[0155] Based on the route transition response message, the source donor-CU generates BAP Header Rewriting information, routing information for the target donor-CU domain, and RLC channel mapping information between the previous hop node address belonging to the source donor-CU topology and the next hop node address belonging to the target donor-CU topology.

[0156] In an F1AP message (e.g., BAP MAPPING CONFIGURATION), the transition node sends BAP Header Rewriting Information, routing information for the target donor-CU domain, and RLC channel mapping information between the previous hop node address belonging to the source donor-CU topology and the next hop node address belonging to the destination donor-CU topology.

[0157] The source donor-CU sends an RRC reconfiguration message to the transition node (including the IP addresses assigned by the target donor-DU for F1 and non-F1 services).

[0158] The source donor-CU sends an RRC reconfiguration message to the child node (including the IP addresses assigned by the target donor-DU for F1 and non-F1 services).

[0159] The target donor-CU updates routing information and RLC channel mapping information for nodes on the target path.

[0160] The source donor-CU initiates handover preparation for the transition node.

[0161] Once the transition node completes the handover, it applies the IP addresses for the above configured F1 and non-F1 services.

[0162] Once the transition node completes the handover, the child node applies the IP addresses for the above configured F1 and non-F1 services.

[0163] The destination donor-CU sends a context release request for the IAB-MT of the transition node to the source donor-CU.

[0164] The above signaling process is merely for the purpose of roughly describing an embodiment of the present invention, and the present invention is not limited thereto. For specific details of the signaling, reference may be made to related art.

[0165] The above-described embodiments are merely illustrative of the present invention, and the present invention is not limited thereto. Appropriate modifications may be made based on the above-described embodiments. For example, each of the above-described embodiments may be used alone, or one or more of the above-described embodiments may be used in combination.

[0166] According to this embodiment, before the IAB-MT of the IAB node performs handover, the IAB node or the child node receives the route transition configuration for uplink data sent by the network device, and when the IAB-MT completes handover, the IAB node or the child node applies the route transition configuration, thereby reducing or avoiding the problem of uplink data being discarded, and reducing transmission delay and service interruption time.

[0167] <Example 2> The embodiment of the present invention provides a route transition method and will be explained from the donor aggregation unit side. Explanations of the same contents as in the first embodiment will be omitted.

[0168] In some embodiments, the parent node of the IAB node before migration uses a first donor distribution unit (donor-DU), the parent node of the IAB node after migration uses a second donor distribution unit, the first donor-DU belongs to the first donor aggregation unit, and the second donor-DU belongs to the second donor aggregation unit.

[0169] The first donor aggregation unit (donor-CU) sends a path transition request message to the second donor-CU before sending a handover request for the IAB-MT of the IAB node.

[0170] The first donor-CU receives the route transition response message sent by the second donor-CU.

[0171] In some embodiments, the route transition request message and the route transition response message are sent over an Xn interface, and the route transition request message and the route transition response message include the XnAP identifier of the IAB node.

[0172] In some embodiments, the first donor-CU sends a path transition request message to the second donor-CU before sending a handover request for the IAB-MT of the IAB node, and in some embodiments, the path transition request message includes a target cell identifier or a target parent node identifier for the handover of the IAB-MT of the IAB node.

[0173] In some embodiments, the path transition request message includes an IP address anchored to the first donor-DU for the BAP address of the first donor-DU, where 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.

[0174] In some embodiments, the route transition response message includes first configuration information, which is used to configure an IP address anchored to the first donor-DU to be replaced with an IP address anchored to the second donor-DU.

[0175] In some embodiments, the first configuration information is included in an RRC reconfiguration message for the IAB node or child node that is included in a path transition response message.

[0176] In some embodiments, the first donor aggregation unit transmits the first configuration information to the IAB node, or transmits the first configuration information to a child node or a parent node of the child node, before transmitting a handover command RRC message to the IAB node.

[0177] In some embodiments, the first donor aggregation unit (donor-CU) sends a path transition configuration for uplink data to the IAB node, or sends a path transition configuration for uplink data to a child node or a parent node of the child node, before sending a handover command RRC message to the IAB node.

[0178] The above-described embodiments are merely illustrative of the present invention, and the present invention is not limited thereto. Appropriate modifications may be made based on the above-described embodiments. For example, each of the above-described embodiments may be used alone, or one or more of the above-described embodiments may be used in combination.

[0179] According to this embodiment, before the IAB-MT of the IAB node performs handover, the IAB node or the child node receives the route transition configuration for uplink data sent by the network device, and when the IAB-MT completes handover, the IAB node or the child node applies the route transition configuration, thereby reducing or avoiding the problem of uplink data being discarded, and reducing transmission delay and service interruption time.

[0180] In addition, in some other embodiments, after sending a handover request for the IAB-MT of the IAB node, the first donor aggregation unit (donor-CU) may send a path transition request message to the second donor-CU and send the first configuration information to the IAB node or child node before sending a handover command RRC message to the IAB node, but the embodiments of the present invention are not limited thereto.

[0181] Furthermore, the method of transmitting the first configuration information may be used in a scenario in which the transmission paths of some services are migrated to the network topology domain of a second donor-CU when an IAB node maintains dual connectivity with a first donor-CU and the first donor-CU, and in a scenario in which the transmission paths of all services are migrated to the network topology domain of a second donor-CU when an IAB node's IAB-MT is re-established in the second donor-CU, where a parent node before the service path migration uses a first donor-DU and a parent node after the migration uses a second donor-DU. The first configuration information is Used to configure the replacement of the IP address anchored to the first donor-DU with the IP address anchored to the second donor-DU for the migrated service.

[0182] Example 3 The embodiment of the present invention provides an IAB node device, and the description of the same content as in the first and second embodiments will be omitted. The device may be, for example, an IAB node or a child node in an IAB system, or may be a constituent element or component configured in the IAB node or the child node. The parent node of the IAB node device before migration uses a first donor distribution unit (donor-DU), and the parent node after migration of the IAB node device uses a second donor distribution unit.

[0183] 16 is a schematic diagram of an example of an IAB node device according to an embodiment of the present invention. As shown in FIG. 16, an IAB node device 1600 includes a receiving unit 1601 and a processing unit 1602.

[0184] In some embodiments, the receiving unit 1601 receives a path transition configuration in uplink data sent by a network device before an IAB-MT of an IAB node performs a handover, and the processing unit 1602 applies the path transition configuration when the IAB-MT completes the handover.

[0185] In some embodiments, the first donor distribution unit (donor-DU) and the second donor distribution unit belong to the same donor aggregation unit (donor-CU). The path transition configuration is sent by the donor aggregation unit to the IAB node or child node via an F1AP message or an RRC message.

[0186] In some embodiments, the route transition configuration includes adding an inter-donor distribution unit routing identifier rewrite configuration to indicate a mapping relationship between the first routing identifier and the second routing identifier, adding a routing configuration including a mapping relationship between the second routing identifier and a BAP address of a immediately subsequent hop node of the IAB node, and adding an RLC radio link control channel mapping configuration to indicate a mapping relationship between the BAP address of the immediately subsequent hop node of the IAB node and an ingress link radio link control (RLC) channel identifier, the BAP address of the immediately subsequent hop node of the IAB node and an egress link RLC channel identifier, where the destination BAP address of the first routing identifier is the BAP address of the first donor-DU, and the destination BAP address of the second routing identifier is the BAP address of the second donor-DU.

[0187] In some embodiments, the processing unit 1602 rewrites the first routing identifier carried in the BAP header of the uplink data to the second routing identifier.

[0188] In some embodiments, the receiver 1601 receives first configuration information sent by the donor aggregation unit before the IAB-MT performs handover. The first configuration information is used to configure an IP address anchored to the first donor-DU to be replaced with an IP address anchored to the second donor-DU. 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.

[0189] In some embodiments, the processing unit 1602 replaces the IP address anchored to the first donor-DU with the IP address anchored to the second donor-DU when the IAB-MT completes the random access of the handover.

[0190] In some embodiments, the first configuration information of the IAB node is transmitted by the donor aggregation unit via a handover command Radio Resource Control (RRC) message or an RRC reconfiguration message, and the first configuration information of the child node is transmitted by the donor aggregation unit via an RRC reconfiguration message.

[0191] In some embodiments, the first configuration information is IP address configuration information for the BAP address of the first donor-DU, for example, the first configuration information is used to change the IP address anchored to the first donor-DU for the BAP address of the first donor-DU to an IP address anchored to the second donor-DU.

[0192] In some embodiments, the route transition configuration includes adding a routing configuration including a mapping relationship between the second routing identifier and a BAP address of a immediately subsequent hop node of the IAB node, and adding an RLC channel mapping configuration to indicate a mapping relationship between the BAP address of the immediately subsequent hop node of the IAB node, an ingress link RLC channel identifier, a BAP address of the immediately subsequent hop node of the IAB node, and an egress link RLC channel identifier, wherein the destination BAP address of the second routing identifier is the BAP address of the second donor-DU.

[0193] In some embodiments, the receiver 1601 receives second configuration information sent by the donor aggregation unit before the IAB-MT performs handover, for configuring a second routing identifier, where the second routing identifier is used for uplink F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node.

[0194] The processing unit 1602 applies the second routing identifier when the IAB node completes the random access of the handover.

[0195] In some embodiments, the receiver 1601 receives third configuration information sent by the donor aggregation unit before the IAB-MT performs the handover, where the third configuration information is used to configure an IP address anchored to the second donor-DU.

[0196] In some embodiments, the third configuration information of the IAB node is transmitted by the donor aggregation unit via a handover command radio resource control (RRC) message or an RRC reconfiguration message, and the third configuration information of the child node is transmitted by the donor aggregation unit via an RRC reconfiguration message.

[0197] In some embodiments, the third configuration information includes configuration information for adding an IP address anchored to the second donor-DU for the BAP address of the second donor-DU.

[0198] In some embodiments, the first donor-DU belongs to a first donor aggregation unit and the second donor-DU belongs to a second donor aggregation unit, and the path transition configuration is sent by the first donor aggregation unit to the IAB node or child node via an F1AP message or an RRC message, where the IAB-DU of the IAB node maintains an F1 connection with the first donor aggregation unit.

[0199] In some embodiments, the path transition configuration includes adding an inter-donor aggregation unit routing identifier rewrite configuration to indicate a mapping relationship between the first routing identifier and the second routing identifier, adding a routing configuration including a mapping relationship between the second routing identifier and a BAP address of a immediately subsequent hop node of the IAB node, and adding an RLC channel mapping configuration to indicate a mapping relationship between a BAP address of a immediately subsequent hop node of the IAB node and an ingress link RLC channel identifier, and a BAP address of a immediately subsequent hop node of the IAB node and an egress link RLC channel identifier.

[0200] Here, the first routing identifier and the BAP address of the IAB node's immediately preceding hop node belong to the network topology domain of the first donor aggregation unit, the destination BAP address of the first routing identifier is the BAP address of the first donor-DU, the second routing identifier and the BAP address of the IAB node's immediately following hop node belong to the network topology domain of the second donor aggregation unit, and the destination BAP address of the second routing identifier is the BAP address of the second donor-DU.

[0201] In some embodiments, the processing unit 1602 rewrites the first routing identifier carried in the BAP header of the uplink data to the second routing identifier.

[0202] In some embodiments, the receiver 1601 receives first configuration information sent by a first donor aggregation unit before an IAB-MT of the IAB node performs a handover, where the first configuration information is used to configure an IP address anchored to the first donor-DU to be replaced with an IP address anchored to the second donor-DU, where 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.

[0203] Here, the processing unit 1602 replaces the IP address anchored to the first donor-DU with the IP address anchored to the second donor-DU when the IAB-MT of the IAB node completes the random access of the handover.

[0204] The above-described embodiments are merely illustrative of the present invention, and the present invention is not limited thereto. Appropriate modifications may be made based on the above-described embodiments. For example, each of the above-described embodiments may be used alone, or one or more of the above-described embodiments may be used in combination.

[0205] Although the above description is limited to the components or modules related to the present invention, the present invention is not limited thereto. The IAB node device 1600 according to the embodiment of the present invention may further include other components or modules. For specific details of these components or modules, please refer to the related art.

[0206] Furthermore, for convenience of explanation, Figure 16 only exemplifies the connection relationships or signal directions between various components or modules, but it will be apparent to those skilled in the art that various related technologies such as bus connections can be used. The various components or modules described above may be implemented by hardware devices such as a processor, a memory, a transmitter, and a receiver, and the present invention is not limited thereto.

[0207] According to this embodiment, before the IAB-MT of the IAB node performs handover, the IAB node or the child node receives the route transition configuration for uplink data sent by the network device, and when the IAB-MT completes handover, the IAB node or the child node applies the route transition configuration, thereby reducing or avoiding the problem of uplink data being discarded, and reducing transmission delay and service interruption time.

[0208] Example 4 The present embodiment provides an IAB donor device, and the description of the same content as in Embodiments 1 to 3 will be omitted. The device may be, for example, an IAB donor-CU in an IAB system, or may be a constituent element or component configured in the IAB donor-CU.

[0209] The IAB system includes an IAB-donor device and an IAB node device, where a parent node of the IAB node device before migration uses a first donor distribution unit (donor-DU), a parent node of the IAB node device after migration uses a second donor distribution unit, the first donor-DU belongs to the first donor aggregation unit, and the second donor-DU belongs to the second donor aggregation unit.

[0210] 17 is a schematic diagram of an example of an IAB donor device according to an embodiment of the present invention. As shown in FIG. 17, the IAB donor device 1700 includes a transmitter 1701 and a receiver 1702. The transmitter 1701 transmits a path transition request message to a second donor-CU before transmitting a handover request for the IAB-MT of the IAB node. The receiver 1702 receives the path transition response message transmitted by the second donor-CU.

[0211] In some embodiments, the route transition request message and the route transition response message are sent over an Xn interface, and the route transition request message and the route transition response message include the XnAP identifier of the IAB node.

[0212] In some embodiments, the path change request message includes a target cell identifier or a target parent node identifier for the handover of the IAB node's IAB-MT.

[0213] In some embodiments, the path transition request message includes an IP address anchored to the first donor-DU for the BAP address of the first donor-DU, where 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.

[0214] The above-described embodiments are merely illustrative of the present invention, and the present invention is not limited thereto. Appropriate modifications may be made based on the above-described embodiments. For example, each of the above-described embodiments may be used alone, or one or more of the above-described embodiments may be used in combination.

[0215] Although the above description is limited to the components or modules relevant to the present invention, the present invention is not limited thereto. The IAB donor device 1700 according to the embodiment of the present invention may further include other components or modules. For specific details of these components or modules, please refer to the related art.

[0216] 17 only exemplifies the connection relationships or signal directions between various components or modules, but it will be apparent to those skilled in the art that various related technologies such as bus connections can be used. The various components or modules described above may be implemented by hardware devices such as a processor, a memory, a transmitter, and a receiver, and the present invention is not limited thereto.

[0217] According to this embodiment, before the IAB-MT of the IAB node performs handover, the IAB node or the child node receives the route transition configuration for uplink data sent by the network device, and when the IAB-MT completes handover, the IAB node or the child node applies the route transition configuration, thereby reducing or avoiding the problem of uplink data being discarded, and reducing transmission delay and service interruption time.

[0218] <Example 5> An embodiment of the present invention provides a communication system including a donor device and an IAB node. The network architecture of the donor device and the IAB node may refer to related art, and the description thereof will be omitted here.

[0219] An embodiment of the present invention further provides an IAB device, which may be an IAB donor device or an IAB node device (IAB node or child node).

[0220] 18 is a schematic diagram of an example of an IAB device according to an embodiment of the present invention. As shown in FIG. 18, the IAB device 1800 may include a processor 1801 (e.g., a central processing unit (CPU)) and a memory 1802, and the memory 1802 is connected to the processor 1801. The memory 1802 may store various data and may further store an information processing program 1805, which is executed under the control of the processor 1801.

[0221] For example, the processor 1801 may be configured to execute a program to implement the route transition method according to Example 1. For example, the processor 1801 may be configured to receive a route transition configuration in uplink data transmitted by a network device before an IAB-MT of an IAB node performs a handover, and to apply the route transition configuration when the IAB-MT completes the handover.

[0222] For example, the processor 1801 may be configured to execute a program to realize the route transition method according to Example 2. For example, the processor 1801 may be configured to send a route transition request message to a second donor-CU and receive a route transition response message sent by the second donor-CU before sending a handover request for the IAB-MT of the IAB node.

[0223] 18, the IAB device 1800 may further include a transceiver 1803 and an antenna 1804. The functions of the above components are similar to those of the prior art, and a description thereof will be omitted here. The IAB device 1800 does not need to include all the units shown in FIG. 18. The IAB device 1800 may further include units not shown in FIG. 18, and prior art may be referenced.

[0224] An embodiment of the present invention further provides a computer-readable program, which, when executed in an IAB node device, causes a computer to execute the route transition method in the first embodiment in the IAB node device.

[0225] An embodiment of the present invention further provides a storage medium having a computer-readable program stored therein, the storage medium causing a computer to execute the route transition method in embodiment 1 in an IAB node device when the program is executed.

[0226] An embodiment of the present invention further provides a computer-readable program, which, when executed in an IAB donor device, causes a computer to perform the path transfer method in embodiment 2 in the IAB donor device.

[0227] An embodiment of the present invention further provides a storage medium having a computer-readable program stored thereon, the program, when executed, causing a computer to perform the path transition method of embodiment 2 in an IAB donor device.

[0228] The above-described apparatus and method of the present invention may be realized by hardware or a combination of hardware and software. The present invention relates to a computer-readable program that, when executed by a logic unit, causes the logic unit to implement the above-described apparatus or components, or to implement the above-described various methods or steps. The present invention also relates to a storage medium for storing the above-described program, such as a hard disk, magnetic disk, optical disk, DVD, flash memory, etc.

[0229] Each processing method in each device described with reference to the embodiments of the present invention may be implemented by hardware, a software module executed by a processor, or a combination of both. For example, one or more of the functional block diagrams shown in the drawings, or one or more combinations of the functional block diagrams, may correspond to each software module in a computer program flow or each hardware module. These software modules may correspond to each step shown in the drawings. These hardware modules may be implemented by implementing these software modules in hardware, for example, using a field programmable gate array (FPGA).

[0230] The software module may be located in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, mobile hard disk, CD-ROM, or any other form of storage medium known to those skilled in the art. The storage medium may be connected to the processor so that the processor reads information from or writes information to the storage medium, or the storage medium may be a component of the processor. The processor and the storage medium may be located in an ASIC. The software module may be stored in the memory of the mobile terminal or in a memory card inserted into the mobile terminal. For example, if a device (e.g., a mobile terminal) uses a relatively large-capacity MEGA-SIM card or a large-capacity flash memory device, the software module may be stored in the MEGA-SIM card or the large-capacity flash memory device.

[0231] One or more functional blocks and / or one or more combinations of functional blocks in the functional block diagrams set forth in the figures may be implemented with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any suitable combination thereof to perform the functions described herein. One or more functional blocks and / or one or more combinations of functional blocks in the functional block diagrams set forth in the figures may be implemented with, for example, a combination of computing devices, such as a combination of a DSP and a microprocessor, a combination of multiple microprocessors, one or more microprocessors in combination with a DSP communication, or any other configuration.

[0232] Although the present invention has been described above with reference to specific embodiments, the above description is merely illustrative and does not limit the scope of protection of the present invention. Various modifications and changes may be made to the present invention without departing from the spirit and principles of the present invention, and these modifications and changes are also within the scope of the present invention.

[0233] The following notes are further provided regarding the embodiments including the above examples. (Appendix 1) A route transition method, comprising: a parent node of an IAB node before transition uses a first donor distribution unit (donor-DU); and a parent node of the IAB node after transition uses a second donor distribution unit; Before an IAB-MT of an IAB node performs a handover, the IAB node or a child node receives a path transition configuration for uplink data sent by a network device; and when the IAB-MT completes handover, the IAB node or a child node applies the path transition configuration. (Appendix 2) The first donor distribution unit (donor-DU) and the second donor distribution unit belong to the same donor aggregation unit (donor-CU); 2. The method of claim 1, wherein the path transition configuration is sent by the donor aggregation unit to the IAB node or child node via an F1AP message or a radio resource control (RRC) message. (Appendix 3) The route transition configuration includes: adding a routing identifier rewrite configuration between donor distribution units to indicate a mapping relationship between the first routing identifier and the second routing identifier; adding a routing configuration including a mapping relationship between the second routing identifier and a backhaul adaptation protocol (BAP) address of a next-hop node of the IAB node; and adding an RLC channel mapping configuration to indicate a mapping relationship between a BAP address of a previous hop node of the IAB node and an ingress link Radio Link Control (RLC) channel identifier, and a BAP address of a next hop node of the IAB node and an egress link RLC channel identifier; The destination BAP address of the first routing identifier is the BAP address of the first donor-DU; 3. The method of claim 2, wherein the destination BAP address of the second routing identifier is the BAP address of the second donor-DU. (Appendix 4) 4. The method of claim 3, further comprising the step of the IAB node rewriting the first routing identifier carried in a BAP header of uplink data to the second routing identifier. (Appendix 5) Before the IAB-MT performs a handover, the IAB node receives first configuration information sent by the donor aggregation unit; the first configuration information is used to configure an IP address anchored to the first donor-DU to be replaced with an IP address anchored to the second donor-DU; 5. The method of claim 3 or 4, wherein the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node. (Appendix 6) 6. The method of claim 5, further comprising the step of the IAB node replacing the IP address anchored to the first donor-DU with the IP address anchored to the second donor-DU when the IAB-MT completes handover random access. (Appendix 7) before the IAB-MT performs handover, the child node or a parent node of the child node receives first configuration information sent by the donor aggregation unit; the first configuration information is used to configure an IP address anchored to the first donor-DU to be replaced with an IP address anchored to the second donor-DU; 5. The method of claim 3 or 4, wherein the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the child node. (Appendix 8) 8. The method of claim 7, further comprising the step of the child node replacing an IP address anchored to the first donor-DU with an IP address anchored to the second donor-DU when the IAB-MT completes handover random access. (Appendix 9) 9. The method of any of Supplementary Notes 5 to 8, wherein the first configuration information of the IAB node is transmitted by the donor aggregation unit via a handover command radio resource control (RRC) message or an RRC reconfiguration message. (Appendix 10) 9. The method of any one of Supplementary Notes 5 to 8, wherein the first configuration information of the child node is sent by the donor aggregation unit via an RRC reconfiguration message. (Appendix 11) 11. The method according to any one of claims 5 to 10, wherein the first configuration information is IP address configuration information for a BAP address of the first donor-DU. (Appendix 12) 12. The method of claim 11, wherein the first configuration information is used to change an IP address anchored to the first donor-DU for a BAP address of the first donor-DU to an IP address anchored to the second donor-DU. (Appendix 13) The route transition configuration includes: Adding a routing configuration including a mapping relationship between a second routing identifier and a BAP address of a next-hop node of the IAB node; and adding an RLC channel mapping configuration to indicate a mapping relationship between a BAP address of a previous hop node of the IAB node and an ingress link RLC channel identifier, and a BAP address of a next hop node of the IAB node and an egress link RLC channel identifier; 3. The method of claim 2, wherein the destination BAP address of the second routing identifier is the BAP address of the second donor-DU. (Appendix 14) Before the IAB-MT performs the handover, the IAB node receives second configuration information sent by the donor aggregation unit for configuring a second routing identifier; 14. The method of claim 13, wherein the second routing identifier is used for uplink F1 user plane data, F1 control plane data, or non-F1 data of the IAB node. (Appendix 15) 15. The method of claim 14, wherein the IAB node applies the second routing identifier when the IAB-MT completes random access for handover. (Appendix 16) Before the IAB-MT performs the handover, the child node or a parent node of the child node receives second configuration information sent by the donor aggregation unit for configuring a second routing identifier; 14. The method of claim 13, wherein the second routing identifier is used for uplink F1 user plane data, F1 control plane data, or non-F1 data of the child node. (Appendix 17) 17. The method of claim 16, wherein the child node applies the second routing identifier when the IAB-MT completes random access for handover. (Appendix 18) Before the IAB-MT performs the handover, the IAB node receives third configuration information sent by the donor aggregation unit; 18. The method of any of Supplementary Notes 14 to 17, wherein the third configuration information is used to configure an IP address anchored to the second donor-DU. (Appendix 19) Before the IAB-MT performs a handover, the child node receives third configuration information sent by the donor aggregation unit; 18. The method of any of Supplementary Notes 14 to 17, wherein the third configuration information is used to configure an IP address anchored to the second donor-DU. (Appendix 20) 19. The method of claim 18, wherein the third configuration information of the IAB node is sent by the donor aggregation unit via a handover command radio resource control (RRC) message or an RRC reconfiguration message. (Appendix 21) 20. The method of claim 19, wherein the third configuration information of the child node is sent by the donor aggregation unit via an RRC reconfiguration message. (Appendix 22) 22. The method of any of Addendums 18 to 21, wherein the third configuration information includes configuration information for adding an IP address anchored to the second donor-DU for the BAP address of the second donor-DU. (Appendix 23) the first donor-DU belongs to a first donor aggregation unit; the second donor-DU belongs to a second donor aggregation unit; The path transition configuration is sent by the first donor aggregation unit to the IAB node or child node via an F1AP message or an RRC message; 2. The method of claim 1, wherein the IAB-DU of the IAB node maintains an F1 connection with the first donor aggregation unit. (Appendix 24) The route transition configuration includes: adding an inter-donor aggregation unit routing identifier rewrite configuration to indicate a mapping relationship between the first routing identifier and the second routing identifier; adding a routing configuration including a mapping relationship between the second routing identifier and a BAP address of a next-hop node of the IAB node; and adding an RLC channel mapping configuration to indicate a mapping relationship between a BAP address of a previous hop node of the IAB node and an ingress link RLC channel identifier, and a BAP address of a next hop node of the IAB node and an egress link RLC channel identifier; The first routing identifier and the BAP address of the previous hop node of the IAB node belong to a network topology domain of the first donor aggregation unit; The destination BAP address of the first routing identifier is the BAP address of the first donor-DU; The second routing identifier and the BAP address of the next hop node of the IAB node belong to a network topology domain of the second donor aggregation unit; 24. The method of claim 23, wherein the destination BAP address of the second routing identifier is the BAP address of the second donor-DU. (Appendix 25) 25. The method of claim 24, wherein the IAB node rewrites the first routing identifier carried in a BAP header of uplink data to the second routing identifier. (Appendix 26) Before an IAB-MT performs a handover, the IAB node receives first configuration information sent by the first donor aggregation unit; the first configuration information is used to configure an IP address anchored to the first donor-DU to be replaced with an IP address anchored to the second donor-DU; 26. The method of claim 24 or 25, wherein the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the IAB node. (Appendix 27) 27. The method of claim 26, further comprising the step of the IAB node replacing an IP address anchored to the first donor-DU with an IP address anchored to the second donor-DU when the IAB-MT completes handover random access. (Appendix 28) Before an IAB-MT of the IAB node performs a handover, the child node or a parent node of the child node receives first configuration information sent by the first donor aggregation unit; the first configuration information is used to configure an IP address anchored to the first donor-DU to be replaced with an IP address anchored to the second donor-DU; 26. The method of claim 24 or 25, wherein the IP address is used for F1 user plane data, F1 control plane data, or non-F1 data of the child node. (Appendix 29) 29. The method of claim 28, further comprising the step of the child node replacing an IP address anchored to the first donor-DU with an IP address anchored to the second donor-DU when the IAB-MT completes handover random access. (Appendix 30) 30. The method of any of Supplementary Notes 26 to 29, wherein the first configuration information is sent by the donor aggregation unit to the IAB node via a handover command radio resource control (RRC) message or an RRC reconfiguration message. (Appendix 31) 30. The method of any of Supplementary Notes 26 to 29, wherein the first configuration information is sent by the donor aggregation unit to the child node or a parent node of the child node via an RRC reconfiguration message. (Appendix 32) 32. The method of any one of claims 26 to 31, wherein the first configuration information is IP address configuration information for a BAP address of the first donor-DU. (Appendix 33) 33. The method of claim 32, wherein the first configuration information is used to change an IP address anchored to the first donor-DU for a BAP address of the first donor-DU to an IP address anchored to the second donor-DU. (Appendix 34) A route transition method, wherein a parent node of an IAB node before migration uses a first donor distribution unit (donor-DU), a parent node of the IAB node after migration uses a second donor distribution unit, the first donor-DU belongs to the first donor aggregation unit, and the second donor-DU belongs to the second donor aggregation unit; The first donor aggregation unit (donor-CU) sends a path transition request message to the second donor-CU before sending a handover request for the IAB-MT of the IAB node; receiving, by the first donor-CU, a route transition response message sent by the second donor-CU. (Appendix 35) The route transition request message and the route transition response message are transmitted via an Xn interface; 35. The method of claim 34, wherein the route transition request message and the route transition response message include an XnAP identifier of the IAB node. (Appendix 36) the path transition request message includes an IP address anchored to the first donor-DU for the BAP address of the first donor-DU; 36. The method of claim 34 or 35, 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. (Appendix 37) 36. The method of claim 34 or 35, wherein the path change request message includes a target cell identifier or a target parent node identifier for the IAB-MT handover of the IAB node. (Appendix 38) the route transition response message includes first configuration information; 38. The method of any of claims 34 to 37, wherein the first configuration information is used to configure replacing an IP address anchored to the first donor-DU with an IP address anchored to the second donor-DU. (Appendix 39) 39. The method of claim 38, wherein the first configuration information is included in an RRC reconfiguration message for the IAB node or the child node, which is included in the route transition response message. (Appendix 40) 39. The method of claim 38, further comprising the step of: the first donor aggregation unit sending the first configuration information to the IAB node, or sending the first configuration information to the child node or a parent node of the child node, before sending a handover command RRC message to the IAB node. (Appendix 41) 41. The method of any of Supplementary Notes 34 to 40, further comprising the step of: the first donor aggregation unit (donor-CU) sending an uplink data path transition configuration to the IAB node, or sending an uplink data path transition configuration to the child node or a parent node of the child node, before sending a handover command RRC message to the IAB node. (Appendix 42) An IAB node device including a memory in which a computer program is stored and a processor, wherein the processor is configured to execute the computer program to realize a route transition method described in any one of Supplementary Notes 1 to 33. (Appendix 43) An IAB donor device comprising: a memory having a computer program stored therein; and a processor, wherein the processor is configured to execute the computer program to realize a path transition method described in any one of appendices 34 to 41. (Appendix 44) A communication system including an IAB donor device and an IAB node device, wherein the IAB node device is configured to perform a route transition method described in any one of Supplementary Notes 1 to 33, and the IAB donor device is configured to perform a route transition method described in any one of Supplementary Notes 34 to 41.

Claims

1. An integrated access backhaul (IAB) node, wherein a parent node of the IAB node before migration uses a first donor distribution unit, a parent node of the IAB node after migration uses a second donor distribution unit, the first donor distribution unit belongs to a first donor aggregation unit, and the second donor distribution unit belongs to a second donor aggregation unit; a receiving unit configured to receive configuration information sent by the first donor aggregation unit before an IAB-MT of the IAB node performs a handover, the configuration information including at least a first transport network layer address anchored to the second donor distribution unit; a processing unit that applies the configuration information when the IAB-MT completes handover; The receiving unit receives the configuration information sent by the first donor aggregation unit before the IAB-MT of the IAB node performs a handover; the configuration information is used to configure a second transport network layer address anchored to the first donor distribution unit to be replaced with the first transport network layer address anchored to the second donor distribution unit; an IAB node, wherein each of the first transport network layer address and the second transport network layer address is used for at least one of F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or a child node.

2. The IAB node of claim 1 , wherein the receiver receives the configuration information via a radio resource control message.

3. a child IAB node of the IAB node receiving configuration information sent by the first donor aggregation unit via a radio resource control message; 2. The IAB node of claim 1, wherein the configuration information includes at least a first transport network layer address of the child IAB node anchored to the second donor distribution unit.

4. The IAB node of claim 1 , wherein the configuration information further includes at least a BH RLC channel on a target path, a BAP routing identifier configuration for a service on the target path.

5. 2. The IAB node of claim 1, wherein the configuration information is transmitted by the second donor aggregation unit to the first donor aggregation unit using a handover request acknowledgement, by the first donor aggregation unit to a parent node of the IAB-MT using a UE context modification request, and by the parent node to the IAB-MT using a radio resource control configuration.

6. The IAB node of claim 1 , wherein the IAB-DU of the IAB node maintains an F1 connection with the first donor aggregation unit.

7. A method for processing an IAB node included in a communication system, the communication system including: a first parent node using a first donor distribution unit before a transition; and a second parent node using a second donor distribution unit after a transition, the first donor distribution unit belonging to a first donor aggregation unit, and the second donor distribution unit belonging to a second donor aggregation unit, the method comprising: receiving configuration information sent by the first donor aggregation unit before the IAB-MT of the IAB node performs a handover, the configuration information including at least a first transport network layer address anchored to the second donor distribution unit; applying the first transport network layer address when the IAB-MT completes the handover; receiving the configuration information sent by the first donor aggregation unit before the IAB-MT of the IAB node performs a handover; the configuration information is used to configure a second transport network layer address anchored to the first donor distribution unit to be replaced with the first transport network layer address anchored to the second donor distribution unit; 10. The method of claim 1, wherein each of the first transport network layer address and the second transport network layer address is used for at least one of F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or child node.

8. An integrated access backhaul (IAB) system, comprising: an IAB donor; and an IAB node; A parent node of the IAB node before migration uses a first donor distribution unit, a parent node of the IAB node after migration uses a second donor distribution unit, the first donor distribution unit belongs to a first donor aggregation unit, and the second donor distribution unit belongs to a second donor aggregation unit; The IAB node receives configuration information sent by the first donor aggregation unit before the IAB-MT of the IAB node performs a handover, the configuration information including at least a first transport network layer address anchored to the second donor distribution unit, and applies the first transport network layer address when the IAB-MT completes the handover; the IAB node receives the configuration information sent by the first donor aggregation unit before the IAB-MT of the IAB node performs a handover; the configuration information is used to configure a second transport network layer address anchored to the first donor distribution unit to be replaced with the first transport network layer address anchored to the second donor distribution unit; 1. An IAB system, wherein each of the first transport network layer address and the second transport network layer address is used for at least one of F1 user plane data, F1 control plane data, or non-F1 data of the IAB node or a child node.

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