Routing methods, devices, and systems

Abstract

An embodiment of the present invention provides a routing method, an apparatus and a system, the routing method including: an IAB node receiving flow control indication information for a BH RLC channel and / or a routing from a child node, the flow control indication information including an available buffer size for the BH RLC channel and an identifier of the BH RLC channel and / or including an available buffer size for the routing and an identifier of the routing, and the IAB node routing downlink data based on the available buffer size.

Description

Technical Field

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

Background Art

[0002] For the future deployment of seamless cellular networks, the deployment of very flexible and ultra-high density NR cells is required. Ultra-high density networks are one of the goals of 5G, and the deployment of NR networks that do not require wired backhaul is important for realizing 5G ultra-high density networks. Since 5G millimeter waves narrow the cell coverage, a wireless self-backhaul system requires multi-hop to meet the deployment needs. 5G's high bandwidth, large-scale MIMO and beam systems make it easier to develop a wireless self-backhaul system for ultra-high density NR cells in 5G than in LTE. To develop such a multi-hop system with a wireless self-backhaul, 3GPP (registered trademark) started the research and standardization of the IAB (Integrated access and backhaul) project in R16.

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

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

[0005] The IAB-node function is divided into two parts: the gNB-DU function, also known as the IAB-DU (Distributed Unit), and the UE function, also known as the IAB-MT (Mobile Terminal). The IAB-DU implements the functions of the network-side device, is connected to downstream child IAB-nodes, provides NR air interface access to the UE and downstream child IAB-nodes, and establishes an F1 connection with the IAB Donor-CU. The IAB-MT implements some of the functions of the termination device and is connected to the upstream parent IAB-node or IAB-Donor DU. The IAB-MT includes the functions of the physical layer, Layer 2, RRC (Radio Resource Control), and NAS (Non-Access Stratum), and is indirectly connected to the IAB Donor-CU and the Core Network (CN).

[0006] In an IAB system, an IAB node can access the network in either 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.

[0009] As shown in Figures 5 and 6, F1-U and F1-C are established on the transmission (IP) layer between the IAB-DU and the IAB-Donor-CU, and Figures 5 and 6 show a two-hop wireless backhaul and a one-hop wired backhaul. In the backhaul link, the transmission (IP) layer is carried by a backhaul adaptive protocol (BAP) sublayer, with BAP entities at the IAB-node implementing the routing functionality of the IAB system, and the IAB-Donor CU providing the routing table. BAP PDUs (Protocol Data Units) are carried on the RLC (Radio Link Control) channels of the backhaul link, and multiple RLC channels of the backhaul link may be configured by the IAB-Donor to carry services with different priorities and QoS (Quality of Service), with BAP entities mapping BAP PDUs to different backhaul RLC channels.

[0010] Furthermore, the above explanation of the background art is merely intended to provide a clearer and more complete explanation of the present invention's structure and to facilitate understanding for those skilled in the art. These structures, as described in the background art section of the present invention, should not be construed as being well-known to those skilled in the art. [Overview of the project] [Problems that the invention aims to solve]

[0011] According to the inventors of this invention, with respect to uplink data, if a dual connection is established to an IAB node, and an RLF occurs on one link, the IAB node cannot update the routing policy for the relevant data based on the RLF link. On the other hand, with respect to downlink data, if a child node sends a flow control instruction to the IAB node, there is no specific solution as to how the IAB node will reroute the downlink data in accordance with the flow control instruction.

[0012] To solve at least one of the above problems or other similar problems, embodiments of the present invention provide routing methods, apparatus and systems. [Means for solving the problem]

[0013] In one embodiment of the present invention, a routing device is provided, configured in an IAB node in an IAB system, comprising: a receiving unit that receives flow control instruction information for BH RLC channels and / or routing from a child node, wherein the flow control instruction information includes the available buffer size for the BH RLC channel and the identifier of the BH RLC channel, and / or the available buffer size for the routing and the identifier of the routing; and a processing unit that routes downlink data based on the available buffer size.

[0014] In another embodiment of the present invention, a routing device is provided, configured as a child node of an IAB node in an IAB system, comprising a transmitting unit that transmits flow control instruction information based on a BH RLC channel to the IAB node when the BH RLC channel buffer of the child node exceeds a third buffer threshold, wherein the flow control instruction information includes the available buffer size for the BH RLC channel and an identifier for the BH RLC channel, so that the IAB node routes downlink data based on the available buffer size.

[0015] In another embodiment of the present invention, a routing device is provided, configured as a child node of an IAB node in an IAB system, comprising a transmitting unit that transmits routing-based flow control instruction information to the IAB node when the buffer of a fifth routing exceeds a fourth buffer threshold, wherein the flow control instruction information includes the available buffer size and a fifth routing identifier for the fifth routing, so that the IAB node routes downlink data based on the available buffer size.

[0016] In another embodiment of the present invention, a routing device configured in an IAB node in an IAB system is provided, which includes a transmitting unit that transmits RLF instruction information to a child node when it is detected that an RLF has occurred on one or more ingress links, wherein the RLF instruction information includes a routing identifier in the routing configuration of the routing table of the IAB node, where the egress link corresponding to the next hop address is the link on which the RLF occurred, so that the child node routes uplink data based on the RLF instruction information.

[0017] Another embodiment of the present invention provides a routing device configured as a child node of an IAB node in an IAB system, comprising: a receiving unit that receives RLF instruction information from an IAB node, wherein the RLF instruction information includes a routing identifier that the link corresponding to the address of the next hop is the link where the RLF occurred; and a processing unit that routes uplink data based on the RLF instruction information.

[0018] One of the advantageous effects of the embodiments of the present invention is as follows: Since the IAB node (as a child node) can determine whether uplink routing is available based on the RLF instruction information of the parent node, it can avoid selecting unavailable routing when selecting routing for uplink data, thereby avoiding loss and unreachability of uplink data. Furthermore, since the IAB node (as a parent node) can determine whether downlink routing and downlink BH RLC channels are congested based on the flow control instruction information of the child node, it can avoid selecting congested routing and BH RLC channels when selecting routing and BH RLC channels for downlink data, thereby mitigating and resolving the problem of downlink data congestion and loss.

[0019] As shown in the following description and drawings, specific embodiments of the present invention are disclosed in detail, illustrating methods in which the principles of the present invention can be employed. However, the scope of embodiments of the present invention is not limited to these. Embodiments of the present invention include modified, altered, and equivalent forms within the scope of the gist and items 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 replace features in other embodiments.

[0021] In the present text, the term "comprising / having" means that a feature, member, step or requirement exists, and does not exclude the existence or addition of one or more other features, members, steps or requirements.

Brief Description of the Drawings

[0022] The elements and features described in one drawing and one embodiment of the present invention may be combined with the elements and features shown in one or more additional drawings or embodiments. Also, in the drawings, like reference numerals indicate corresponding elements in multiple drawings, and may indicate corresponding elements used in one or more embodiments.

[0023] The included drawings are used to further understand the embodiments of the present invention, form part of the specification, are used to illustrate the embodiments of the present invention, and explain the principles of the present invention together with the textual description. Note that the drawings described below are merely some embodiments of the present invention, and those skilled in the art can easily conceive of other drawings based on these drawings. [Figure 1] It is a schematic diagram of an example of an IAB system. [Figure 2] It is a schematic diagram of the IAB architecture in SA mode. [Figure 3] It is a schematic diagram of the IAB architecture in EN-DC mode. [Figure 4] It is a schematic diagram of the parent node (parent IAB-node) and child node (child IAB-node) of one IAB node (IAB-node). [Figure 5] It is a schematic diagram of the F1-U protocol stack of the IAB system. [Figure 6] It is a schematic diagram of the F1-C protocol stack of the IAB system. [Figure 7] It is a schematic diagram of an example of routing selection. [Figure 8] It is a schematic diagram of an example of the IAB node 4 routing uplink data based on the RLF indication. [Figure 9]This is a schematic diagram of a flow-controlled BAP-controlled PDU based on a BH RLC channel. [Figure 10] This is a schematic diagram of a flow-controlled BAP-controlled PDU based on Routing ID. [Figure 11] This is a schematic diagram illustrating an example of how IAB node 3 routes downlink data based on flow control instructions. [Figure 12] This is a schematic diagram of an example of a routing method according to Embodiment 1 of the present invention. [Figure 13] This is a schematic diagram illustrating an example of routing relationships between IAB nodes. [Figure 14A] This is a schematic diagram of another example of the routing method according to Embodiment 1 of the present invention. [Figure 14B] This is a schematic diagram of another example of the routing method according to Embodiment 1 of the present invention. [Figure 15] This is a schematic diagram of an example of the routing process of the routing method according to Example 1. [Figure 16] This is a schematic diagram of another example of the routing process of the routing method according to Example 1. [Figure 17] This is a schematic diagram of an example of a routing method according to Embodiment 2 of the present invention. [Figure 18] This is a schematic diagram illustrating another example of routing relationships for IAB nodes. [Figure 19] This is a schematic diagram of another example of the routing method according to Embodiment 2 of the present invention. [Figure 20] This is a schematic diagram illustrating another example of routing relationships for IAB nodes. [Figure 21] This is a schematic diagram illustrating another example of routing relationships for IAB nodes. [Figure 22] This is a schematic diagram of an example of a routing device according to Embodiment 3 of the present invention. [Figure 23] This is a schematic diagram of another example of a routing device according to Embodiment 3 of the present invention. [Figure 24] This is a schematic diagram of another example of a routing device according to Embodiment 3 of the present invention. [Figure 25]This is a schematic diagram of an example of a routing device according to Embodiment 4 of the present invention. [Figure 26] This is a schematic diagram of another example of a routing device according to Embodiment 4 of the present invention. [Figure 27] This is a schematic diagram of an example of a communication system according to an embodiment of the present invention. [Figure 28] This is a schematic diagram of an example of an IAB node according to an embodiment of the present invention. [Modes for carrying out the invention]

[0024] The above and other features of the present invention will become apparent from the following description. Specific embodiments of the present invention are disclosed in detail in the specification and drawings, and some embodiments in which the principles of the present invention can be employed are shown. However, the present invention is not limited to the embodiments described. The present invention includes all modified, altered and equivalent versions of the appended claims.

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

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

[0027] In embodiments of the present invention, the terms "communication network" or "wireless communication network" may mean a network conforming to any communication standard, such as new radio (NR), Long Term Evolution (LTE), Advanced Long Term Evolution (LTE-A, LTE-Advanced), Wideband Code Division Multiple Access (WCDMA®), or High-Speed ​​Packet Access (HSPA).

[0028] Furthermore, communication between devices in a communication system may be carried out according to any stage of communication protocol, which may include, but is not limited to, 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G, and future 5G, 6G, etc., as well as / or other currently known communication protocols or other communication protocols to be developed in the future.

[0029] In embodiments of the present invention, the term "network device" means, for example, a device within a communication system that allows a terminal device to access the communication system and provides services to said terminal device. A network device may include, but is not limited to, a base station (BS), access point (AP), transmission / reception point (TRP), broadcast transmitter, mobile management entity (MME), gateway, server, radio network controller (RNC), base station controller (BSC), etc.

[0030] Among these, base stations may include, but are not limited to, Node B (NodeB or NB), Evolutionary Node B (eNodeB or eNB), and 5G base stations (gNB), as well as Remote Radio Heads (RRH), Remote Radio Units (RRU), relays, or low-power nodes (e.g., femto, pico). The term “base station” may also include some or all of these functions, and each base station may provide communication coverage to a specific geographic area. The term “cell” may mean a base station and / or its coverage area, depending on the context in which the term is used.

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

[0032] Among these, terminal devices may include, but are not limited to, mobile phones (cellular phones), personal digital assistants (PDAs), radio modulators / demodulators, wireless communication devices, handheld devices, machine-type communication devices, laptop computers, cordless phones, smartphones, smartwatches, and digital cameras.

[0033] For example, in scenarios such as the Internet of Things (IoT), the user device may be a monitoring or measurement device or apparatus, and may include, but is not limited to, machine-type communication (MTC) terminals, in-vehicle communication terminals, device-to-device (D2D) terminals, and machine-to-machine (M2M) terminals.

[0034] In the IAB system, routing functionality is implemented by the BAP layer, and each IAB-node stores one routing table (BH routing configuration) and one RLC channel mapping table (BH RLC Channel Mapping Configuration). BAP entities perform routing based on the routing table, RLC channel mapping table, and routing identifiers (Routing IDs) in the packet header of the BAP layer. The Routing ID includes the destination BAP address and path identifiers (path IDs).

[0035] The routing table contains the mapping relationship between the Routing ID and the address of the next-hop node. The RLC channel mapping table contains the mapping relationship between the address of the previous hop, the ingress RLC channel ID, and the next-hop address and the egress RLC channel ID. For each packet, the Routing ID in the header can be used to look up the next-hop address from the routing table. The address of the previous hop and the ingress RLC channel ID are all known. Thus, once the next-hop address is determined, the RLC channel mapping table can be used to look up the egress RLC channel ID based on the address of the previous hop, the ingress RLC channel ID, and the next-hop address. Figure 7 is a schematic diagram of an example of routing selection.

[0036] The IAB-donor DU also stores a routing table (BH routing configuration) and a downlink RLC channel mapping table (Downlink Traffic to BH RLC Channel Mapping Configuration). The IAB-donor DU performs routing based on the routing table, the downlink RLC channel mapping table, and the Routing ID in the packet header of the BAP layer. The routing table contains the mapping relationship between the Routing ID and the address of the next-hop node. The downlink RLC channel mapping table contains the mapping relationship between the destination IP address, DSCP, and the next-hop address and the egress RLC channel ID. For each downlink packet that reaches the IAB-donor DU, the next-hop address can be retrieved from the routing table based on the Routing ID in the header. Once the next-hop address is determined in this way, the egress RLC channel ID is retrieved from the downlink RLC channel mapping table based on the packet's IP address and DSCP.

[0037] According to the inventors' findings of the present invention, regarding the routing of uplink data, if an IAB-node detects a link RLF (Link Recovery Failure) with respect to the parent node, or a failure to recover the link after a link RLF with respect to the parent node, it sends a BH RLF instruction to the child node. Upon receiving this BH RLF instruction, the child node considers the link with respect to the IAB-node to be unavailable. When the child node routes uplink data, if the routing table configuration indicates that the next-hop node for the path corresponding to the uplink data is this IAB-node, the child node reroutes the uplink data to prevent it from being unable to transmit, i.e., selects another path where the next-hop node is not this IAB-node.

[0038] However, if a dual connection is established to an IAB-node, a BH RLF instruction is sent to the child node only when an RLF occurs on both dual-connected links, or when RRC re-establishment fails after an RLF failure, in order to trigger an update of the routing policy for uplink data by the child node. As shown in Figure 8, if IAB node 3 detects that an RLF has occurred on the link between IAB node 1 and IAB node 2, or that RRC re-establishment has failed after an RLF failure, it sends an RLF instruction to IAB node 4, its child node, so that IAB node 4 does not select IAB node 3's link when selecting the routing for uplink data. However, in reality, if an IAB-node is dual-connected to a parent node, the probability of an RLF occurring on both links is low, and if an RLF occurs on only one link, the routing associated with that link is unavailable. At this point, however, the child node cannot obtain RLF information about that link and cannot update the policy for routing related data based on that RLF link.

[0039] Furthermore, according to the inventors of the present invention, regarding the routing of downlink data, if the downlink buffer in a child node of an IAB-node exceeds a certain threshold, or if a child node (IAB-MT) receives a downlink flow control polling message sent by the IAB-node, the child node (IAB-MT) sends a flow control instruction based on the BH RLC channel or the Routing ID to the IAB-node, including the available buffer size for the BH RLC channel or the Routing ID. Figure 9 is a schematic diagram of a flow control BAP control PDU based on the BH RLC channel. Figure 10 is a schematic diagram of a flow control BAP control PDU based on the Routing ID. The IAB-node can reroute the downlink data according to the flow control instruction received from the child node to alleviate congestion in the child node.

[0040] However, prior art does not provide a specific method for how IAB contacts reroute downlink data. As shown in Figure 11, if the buffer at IAB node 4 exceeds its limit, it sends a flow control BAP control PDU (flow control instruction) to IAB node 3, which includes the available buffer size for each routing ID or the available buffer size for the BH RLC channel to and from IAB node 4. IAB node 3 can reroute downlink data to alleviate downlink data congestion at IAB node 4, but prior art does not provide a solution for how IAB node 3 reroutes downlink data.

[0041] The following describes various embodiments of the present invention with reference to the drawings. These embodiments are merely illustrative and do not limit the present invention.

[0042] <Example 1> Embodiments of the present invention provide a routing method for routing downlink data.

[0043] Figure 12 is a schematic diagram of an example of a routing method according to an embodiment of the present invention, described from the perspective of an IAB node in an IAB system, which functions as a parent node. As shown in Figure 12, the method includes the following steps.

[0044] Step 1201: The IAB node receives flow control instruction information from a child node regarding the BH RLC channel and / or routing. The flow control instruction information includes the available buffer size and the identifier of the BH RLC channel, and / or the available buffer size and the identifier of the routing.

[0045] Step 1202: The IAB node routes the downlink data based on the available buffer size.

[0046] In embodiments of the present invention, the flow control instruction information reported by the child node includes the available buffer size for the BH RLC channel and / or routing, and the IAB node can determine whether the corresponding downlink routing and / or downlink BH RLC channel is congested based on the available buffer size. Therefore, when selecting routing and BH RLC channels for downlink data, the selection of congested routing and BH RLC channels can be avoided, thereby mitigating and resolving the problems of congestion and loss of downlink data.

[0047] In some embodiments, an IAB node may determine whether the BH RLC channel and / or routing is congested and available based on the available buffer size, and route downlink data based on whether the BH RLC channel and / or routing is available.

[0048] For example, when an IAB-node (IAB-DU) receives flow control instruction information from an ingress link corresponding to a child node, it may determine whether the routing / BH RLC channel is congested based on the available buffer size of the routing / BH RLC channel in the flow control instruction information. For example, if the available buffer size of the routing is smaller than a first buffer threshold, it is determined that the routing is congested and the egress link corresponding to the child node is unavailable for that routing. Alternatively, if the available buffer size of the BH RLC channel is smaller than a second buffer threshold, it is determined that the BH RLC channel is congested and the BH RLC channel of the link corresponding to the child node is unavailable.

[0049] The first buffer threshold and the second buffer threshold described above may be a single predetermined threshold or a pre-configured threshold, and they may be the same or different, but the present invention is not limited thereto.

[0050] In the above embodiment, routing downlink data based on whether routing is available includes selecting an egress link for the downlink data based on whether said routing is available. That is, if an IAB node (IAB-DU) determines that one routing is congested, it may not select the corresponding routing when selecting a routing for downlink data, and may reroute the downlink data (re-select the routing).

[0051] In embodiments of the present invention, substitution routing for one or more first donor-CU domains may be configured for routing to several second donor-CU domains in order to transmit downlink data. If an IAB-node simultaneously establishes dual connections with the first and second donor-CUs, the IAB-node establishes an F1 connection with the first donor-CU. Some downlink data needs to be sent to the IAB node via the second donor-CU domains. Routing belonging to different donor-CU domains can cause confusion of routing identifiers at the IAB-node, and the IAB-node needs to correct the routing identifier in the packet header of downlinks from the second donor-CU domains to the routing identifier of the first donor-CU domain before routing. In other words, in Figure 13, the routing from the first donor-CU domain (Routing ID #1) and the routing from the second donor-CU domain (Routing ID #2) may be the same. Therefore, IAB-node 3 needs to convert Routing ID #2 to the routing of the first donor-CU domain (Routing ID #3) before sending it to IAB-node 4. Accordingly, a mapping relationship table from the routing ID of the second donor-CU domain to the routing ID of the first donor-CU domain, i.e., an inter-donor-CU downlink routing substitution table, needs to be configured for the IAB-node.

[0052] In embodiments of the present invention, when an IAB-node receives downlink data, it first determines whether the downlink data originates from a first donor-CU domain or a second donor-CU domain. If it originates from the first donor-CU domain, it directly selects an egress link based on the routing ID in the packet header. If it originates from the second donor-CU domain, it modifies the routing identifier in the packet header to the corresponding substituted routing identifier based on the downlink routing substitution table between donor-CUs, and then selects an egress link based on the substituted routing identifier.

[0053] In the above embodiment, before routing downlink data, the IAB-node first determines whether the downlink data is addressed to it, and if it is not addressed to it, it reroutes the data. When an IAB-node simultaneously establishes dual connections with a first donor-CU and a second donor-CU, the two donor-CUs can each have their own configured BAP address at the same time. The IAB-node may determine whether the data is addressed to it based on the destination BAP address in the BAP header of the downlink data and pass it to a higher layer for processing.

[0054] In some embodiments, if an IAB node has a donor-CU downlink routing substitution table configured and it is determined that the downlink data originates from an ingress link corresponding to a second donor-CU, the IAB node may, according to the donor-CU downlink routing substitution table, substitute the first routing identifier (belonging to the second donor-CU topology domain) in the BAP header of the downlink data with the corresponding second routing identifier (belonging to the first donor-CU topology domain).

[0055] Subsequently, the IAB node determines whether there is a routing configuration in its routing table that satisfies the second condition. If there is a routing configuration in the IAB node's routing table that satisfies the second condition, the IAB node sets the egress link corresponding to the next-hop address in the routing configuration as the first egress link of the downlink data. The second condition means that the routing identifier in the routing configuration matches the second routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0056] In the above embodiment, after replacing the first routing identifier in the BAP header of the downlink data with the corresponding second routing identifier, if the destination BAP address of the second routing identifier is a BAP address configured for the IAB node by the first donor-CU, the IAB node may pass the downlink data to the upper layer of the IAB node.

[0057] In some other embodiments, if an IAB node has a donor-CU downlink routing substitution table configured and it is determined that the downlink data is from an ingress link corresponding to a second donor-CU, the IAB node may pass the downlink data to the upper layer of the IAB node if the destination BAP address of the first routing identifier in the BAP header of the downlink data is the BAP address configured for the IAB node by the second donor-CU.

[0058] In some other embodiments, if it is determined that an IAB node does not have a donor-CU downlink routing substitution table configured, or if an IAB node has a donor-CU downlink routing substitution table configured and it is determined that the downlink data is from an ingress link corresponding to a first donor-CU, and the first routing identifier in the header of the downlink data belongs to the first donor-CU topology domain, then the IAB node determines whether there is a routing configuration in the IAB node's routing table that satisfies the first condition.

[0059] When an IAB node's routing table contains a routing configuration that satisfies the first condition, the IAB node uses the egress link corresponding to the next-hop address in the routing configuration as the first egress link for the downlink data. The first condition means that the routing identifier in the routing configuration matches the first routing identifier, and the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0060] In other words, when an IAB node (IAB-DU) receives downlink data, the IAB node checks its routing table to determine whether there is an available route for the routing identifier in the packet header of the downlink data. If the routing identifier in the routing configuration matches the routing identifier in the packet header (both the destination BAP address and the path ID match), and an egress link corresponding to the next-hop address in the routing configuration is available for this routing ID, the IAB node selects the egress link corresponding to the next-hop address in the routing configuration as the egress link for the downlink data packet.

[0061] In the above embodiment, if the routing table of the IAB node does not contain a routing configuration that satisfies the first condition, the IAB node determines whether or not there is a routing configuration in the IAB node's routing table that satisfies the third condition. If there is a routing configuration in the IAB node's routing table that satisfies the third condition, the egress link corresponding to the next-hop address in the routing configuration is set as the first egress link for the downlink data. The third condition means that the destination BAP address of the routing identifier in the routing configuration matches the destination BAP address of the first routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in that routing configuration.

[0062] In other words, if no suitable egress link is found according to the first condition above, it means that there is no available routing for the routing identifier in the header of this downlink data packet, and the IAB node may re-examine whether there is any other available routing for the destination address in this header. If the destination address in a routing configuration matches the destination address in the packet header, and an egress link corresponding to the next-hop address of this routing configuration is available for the routing identifier of this routing configuration, the IAB node selects the egress link corresponding to the next-hop address of this routing configuration as the egress link for the downlink data packet.

[0063] In some other embodiments, if it is determined that an IAB node does not have a donor-CU downlink routing substitution table configured, or if an IAB node has a donor-CU downlink routing substitution table configured and it is determined that the downlink data is from an ingress link corresponding to a first donor-CU, the IAB node passes the downlink data to the upper layer of the IAB node if the destination BAP address of the first routing identifier in the BAP header of the downlink data is the BAP address configured for the IAB node by the first donor-CU.

[0064] In the above embodiment, if a suitable egress link for the downlink data cannot be found by any of the methods of the above embodiment, the IAB node may discard the downlink data or stop transmitting the downlink data.

[0065] The above has exemplified the selection of an egress link for downlink data by an IAB node, with reference to various embodiments. However, the present invention is not limited thereto, and appropriate modifications may be made based on the above embodiments. For example, each of the above embodiments may be used individually, or one or more of the above embodiments may be used in combination.

[0066] In embodiments of the present invention, if a suitable egress link is found for downlink data by the method of the above embodiment, the IAB node may select an egress BH RLC channel for downlink data based on whether or not a BH RLC channel is available.

[0067] In some embodiments, if an IAB node is a donor node of the IAB system, i.e., an IAB-donor-DU, the IAB node may select an egress BH RLC channel for downlink data based on the fourth condition.

[0068] For example, if the IAB node's RLC channel mapping table contains a BH RLC channel configuration that satisfies the fourth condition, the IAB node selects the egress BH RLC channel in the BH RLC channel configuration as the egress BH RLC channel for the downlink data. The fourth condition means that the destination IP address and DSCP in the BH RLC channel configuration match the destination IP address and DSCP in the IP header of the downlink data, the egress link corresponding to the next-hop address in the BH RLC channel configuration matches the first egress link in the downlink data (i.e., the selected egress link), and the egress BH RLC channel in the BH RLC channel configuration is available.

[0069] In other words, the IAB node examines the Downlink Traffic to BH RLC Channel Mapping Configuration, and if there are no available BH RLC channels on the selected egress link (first egress link), the IAB node selects the egress RLC channel of the BH RLC configuration as the egress BH RLC channel for the downlink data packet if both the destination IP address and DSCP of the BH RLC channel configuration match the destination IP address and DSCP in the IP header of the downlink data, and the egress link corresponding to the next hop address in the BH RLC channel configuration matches the selected egress link (first egress link), and that egress link is available for the egress RLC channel in the BH RLC configuration.

[0070] In the above embodiment, if there is no BH RLC channel configuration in the IAB node's RLC channel mapping table that satisfies the fourth condition, in one example, the IAB node may select an available egress BH RLC channel of the first egress link (i.e., the selected egress link) as the egress BH RLC channel for the downlink data. If there is no available BH RLC channel on the first egress link, the IAB node selects a second egress link that is available for the downlink data. That is, if no suitable egress BH RLC channel is found according to the fourth condition, it means that there are no available BH RLC channels for this downlink and egress link, and the IAB node may select any other available egress BH RLC channel for the egress link. If there are no other available egress BH RLC channels on the egress link, the IAB node re-selects the egress link for the downlink.

[0071] In the above embodiment, if there is no BH RLC channel configuration in the IAB node's RLC channel mapping table that satisfies the fourth condition, in other examples, the IAB node may select a second available egress link for the downlink data. If there is no second available egress link, the IAB node selects an available egress BH RLC channel on the first egress link as the egress BH RLC channel for the downlink data. That is, if no suitable egress BH RLC channel is found according to the fourth condition, it means that there are no available BH RLC channels for this downlink data and egress link, and the IAB node may first re-select an egress link, and if no suitable egress link is found, select another available egress BH RLC channel on the previously selected egress link.

[0072] In some other embodiments, if the IAB node is an intermediate node in the IAB system, i.e., an IAB node between the IAB-donor-DU and the access IAB node, the IAB node may select an egress BH RLC channel for downlink data according to the fifth condition.

[0073] For example, if the RLC channel mapping table of an IAB node contains a BH RLC channel configuration that satisfies the fifth condition, the IAB node selects the egress BH RLC channel in the BH RLC channel configuration as the egress BH RLC channel for the downlink data. The fifth condition means that the address of the previous hop and the ingress RLC channel ID in the BH RLC channel configuration match the downlink data, the egress link corresponding to the address of the next hop in the BH RLC channel configuration matches the first egress link in the downlink data (i.e., the selected egress link), and the egress BH RLC channel in the BH RLC channel configuration is available.

[0074] In other words, the IAB node may check the RLC channel mapping table (BH RLC Channel Mapping Configuration) to see if there is a BH RLC channel available on the selected egress link (the first egress link). If the previous hop address and ingress RLC channel ID in the BH RLC channel configuration match the downlink data, and the egress link corresponding to the next hop address in the BH RLC channel configuration matches the selected egress link (the first egress link), and that egress link is available for the egress RLC channel in the BH RLC configuration, the IAB node selects the egress RLC channel in the BH RLC configuration as the egress RLC channel for the downlink data packet.

[0075] In the above embodiment, if there is no BH RLC channel configuration in the IAB node's RLC channel mapping table that satisfies the fifth condition, in one example, the IAB node may select an available egress BH RLC channel of the first egress link (i.e., the selected egress link) as the egress BH RLC channel for the downlink data. If there is no available BH RLC channel on the first egress link, the IAB node selects a second egress link that is available for the downlink data. That is, if a suitable egress BH RLC channel cannot be found according to the fifth condition, it means that there are no available BH RLC channels for this downlink data and egress link, and the IAB node may select any other available egress BH RLC channel on the egress link. If there are no other available egress BH RLC channels on the egress link, the IAB node re-selects the egress link for the downlink data.

[0076] In the above embodiment, if there is no BH RLC channel configuration in the IAB node's RLC channel mapping table that satisfies the fifth condition, in other examples, the IAB node may select a second available egress link for the downlink data. If there is no second available egress link, the IAB node selects an available egress BH RLC channel of the first egress link as the egress BH RLC channel for the downlink data. That is, if no suitable egress BH RLC channel is found according to the fifth condition, it means that there are no available BH RLC channels for this downlink data and egress link, and the IAB node may first re-select an egress link, and if no suitable egress link is found, select another available egress BH RLC channel of the previously selected egress link.

[0077] In embodiments of the present invention, an IAB node may transfer flow control instruction information to its parent node (if any). That is, an IAB node may transfer the above flow control instruction information to its parent node.

[0078] According to the inventors of the present invention, when an IAB node is dual-connected to two Donor-CUs, and a flow control instruction received from a child node indicates a first donor-CU domain routing that can replace a second donor-CU domain routing, it is found that the second donor-CU domain routing passes through the parent node corresponding to the second donor-CU, and that the buffer and congestion state of the first donor-CU domain routing is equivalent to that of the second donor-CU domain routing. Therefore, the IAB node needs to modify the first donor-CU domain routing included in the flow control instruction to the second donor-CU domain routing and forward it to the parent node corresponding to the second donor-CU. In this way, the parent node corresponding to the second donor-CU can know the buffer and congestion of the corresponding routing. If a flow control instruction received from a child node indicates a first donor-CU domain routing that is not replaceable by a second donor-CU domain routing, and it is determined that the first donor-CU domain routing passes through the parent node corresponding to the first donor-CU, the IAB node may forward the flow control instruction directly to the parent node corresponding to the first donor-CU.

[0079] For example, as shown in Figure 13, Routing ID #2 belongs to the second donor-CU domain, while Routing IDs #1 and #3 belong to the first donor-CU domain. Since Routing ID #2 is replaced by Routing ID #3 at IAB-node 3, the congestion state of Routing ID #2 becomes the congestion state of Routing ID #3. When IAB-node 3 receives a flow control instruction for Routing ID #3 from node 4, as can be seen from the routing replacement relationship, it is necessary to change Routing ID #2, which is from the second donor-CU, to Routing ID #2 and forward it to IAB-node 2 so that IAB-node 2 can understand the congestion state of Routing ID #2.

[0080] In some embodiments, an IAB node has a donor-CU downlink routing substitution table configured, and if a routing identifier included in the flow control instruction information (referred to as a third routing identifier and belonging to the first donor-CU topology domain) is determined to belong to a substituted routing identifier in the donor-CU downlink routing substitution table, the IAB node changes the third routing identifier in the flow control instruction information to the corresponding fourth routing identifier (belonging to the second donor-CU topology domain) based on the donor-CU downlink routing substitution table, and sends the flow control instruction information to the egress link corresponding to the second donor-CU. That is, if the received flow control instruction includes a substituted routing ID in the IAB node, the IAB node must correct the routing ID in the flow control instruction to the corresponding substituted routing ID before forwarding it to the parent node, and does not need to correct the buffer domain available at the time of forwarding.

[0081] In some other embodiments, if it is determined that the IAB node does not have a donor-CU downlink routing substitution table configured, or if it is determined that a routing identifier included in the flow control instruction information (referred to as a third routing identifier and belonging to the first donor-CU topology domain) does not belong to a substitution routing identifier in the donor-CU downlink routing substitution table, the IAB node sends flow control instruction information including the third routing identifier to the egress link corresponding to the first donor-CU.

[0082] Figures 14A and 14B are schematic diagrams of two other examples of the routing method according to an embodiment of the present invention, described from the perspective of a child node of an IAB node in an IAB system, which is also an IAB node in the IAB system. This child node is referred to as a "child node" in the embodiments of Figures 14A and 14B in order to distinguish it from the embodiment in Figure 12. Here, redundant explanations of content similar to that in the embodiment in Figure 12 are omitted.

[0083] According to the inventors' findings of the present invention, when an IAB node has dual connections to two Donor-CUs, and one of the first donor-CU domain routings that can replace the second donor-CU domain routing is congested, it can be seen that the buffer and congestion state of the first donor-CU domain routing are equal to the buffer and congestion state of the second donor-CU domain routing, and that the second donor-CU domain routing passes through the parent node corresponding to the second donor-CU. Therefore, the IAB node needs to determine the second donor-CU domain routing that will be replaced by the first donor-CU domain routing and send flow control instruction information including the second donor-CU routing to the parent node corresponding to the second donor-CU. In this way, the parent node corresponding to the second donor-CU can know the buffer and congestion status of the corresponding routing. If the domain routing of a first donor-CU is congested and the domain routing of the second donor-CU is not replaceable, and it is found that the domain routing of the first donor-CU is routed through the parent node corresponding to the first donor-CU, the IAB node may send flow control instruction information carrying the routing of the first donor-CU to the parent node corresponding to the first donor-CU.

[0084] As shown in Figure 14A, the method includes the following steps.

[0085] Step 1401: If the BH RLC channel buffer of an IAB node exceeds a third buffer threshold, the child node of the IAB node sends flow control instruction information based on the BH RLC channel to the IAB node, where the flow control instruction information includes the available buffer size for the BH RLC channel and the identifier of the BH RLC channel, so that the IAB node routes downlink data based on the available buffer size.

[0086] As shown in Figure 14B, the method includes the following steps.

[0087] Step 1401': If the buffer for the fifth routing exceeds the fourth buffer threshold, a child node of the IAB node sends routing-based flow control instruction information to the IAB node, where the flow control instruction information includes the available buffer size and the fifth routing identifier for the fifth routing, so that the IAB node routes the downlink data based on the available buffer size.

[0088] In the above embodiment, if a donor-CU downlink routing substitution table is configured in the child node, and it is determined that the fifth routing identifier belongs to a substitution routing identifier in the donor-CU downlink routing substitution table, the child node includes the sixth routing identifier (belonging to the second donor-CU topology domain) corresponding to the fifth routing identifier (belonging to the first donor-CU topology domain) in the donor-CU downlink routing substitution table in the flow control instruction information and sends it to the egress link corresponding to the second donor-CU. That is, if the downlink buffer of substitution routing IDs exceeds the threshold, the substitution routing IDs in the child node are congested, i.e., the substitution routing IDs are in a congested state at the IAB-node, but the substitution routing IDs in the child node are not known to the IAB-node, so the child node needs to notify the IAB-node of the congestion state of the substitution routing IDs. Therefore, the child node searches for the replaced routing ID of the replaced routing ID according to the donor-CU downlink routing replacement table, and sends the replaced routing ID and the available buffer for the replaced routing ID (i.e., the available buffer for the corresponding replaced routing ID) to the IAB-node in a flow control instruction.

[0089] In the above embodiment, if it is determined that the child node does not have a donor-CU inter-downlink routing substitution table configured, or if it is determined that the fifth routing identifier included in the flow control instruction information (belonging to the first donor-CU topology domain) does not belong to the substitution routing identifiers in the donor-CU inter-downlink routing substitution table, the child node sends the flow control instruction information including the fifth routing identifier to the egress link corresponding to the first donor-CU.

[0090] The following describes a routing method according to an embodiment of the present invention, with reference to specific examples.

[0091] Figure 15 is a schematic diagram of an example of the routing process of a routing method according to an embodiment of the present invention, showing a case where a donor-CU downlink routing substitution table is not configured on the IAB node. In the example in Figure 15, IAB donor DU2 (IAB-donor DU2) is an IAB node and IAB node 4 (IAB-node 4) is a child node.

[0092] Table 1 shows an example of routing identifiers in the example shown in Figure 15.

[0093] [Table 1] Table 2 shows an example of the routing table for IAB donor DU2 in the example shown in Figure 15.

[0094] [Table 2] Table 3 shows an example of a downlink BH RLC mapping table for IAB donor DU2 in the example shown in Figure 15.

[0095] [Table 3] As shown in Figure 15, if the buffer for routing ID #1 on IAB-node 4 (child node) exceeds a certain threshold, IAB-node 4 sends a flow control instruction including routing ID #1 to IAB-Donor DU2 (IAB node). If IAB-donor DU2 determines that routing ID #1 is in a congested state, the egress link corresponding to IAB-node 4 becomes unavailable for routing ID #1.

[0096] In this case, IAB-Donor DU2 updates the routing table to Table 4.

[0097] [Table 4] When IAB-donor DU2 receives downlink data with IP Information #1 in the header, it first maps the data to routing ID #1, and then checks the routing table to see if there is an available route for routing ID #1. A routing configuration matching routing ID #1 was found, but the egress link corresponding to the next hop address IAB-node 4 in this routing configuration is not available for routing ID #1. In other words, there is no available egress link for routing ID #1.

[0098] Next, it checks whether there is an available egress link for the destination address IAB-node 1 in the header. If two routing configurations are found with the destination address IAB-node 1, and egress links corresponding to the next-hop addresses of the two routing configurations (IAB-node 5 and IAB-node 4) are available for the two routing IDs (Routing ID #2 and Routing ID #3), IAB-Donor DU2 may select the egress links corresponding to the next-hop addresses of these two routing configurations (IAB-node 5 and IAB-node 4) as the egress link for the packet.

[0099] Next, IAB-Donor DU2 selects an egress BH RLC channel ID and checks the downlink RLC channel mapping table. Assuming the selected routing and egress links are routing ID #3 and IAB-node 4, respectively, it checks whether there is an available egress RLC channel for routing ID #3 and IAB-node 4. If it finds that the routing ID and next-hop address of the BH RLC configuration match routing ID #3 and IAB-node 4, it may select BH RLC Channel #2 as the egress RLC channel in that BH RLC configuration.

[0100] If the egress RLC channel corresponding to IAB-node 4 is unavailable for BH RLC Channel #2, for example, IAB-donor DU2 will determine that BH RLC Channel #2 is congested, according to the flow control instructions sent from IAB-node 4. The DL BH RLC mapping table of IAB-Donor-DU2 will be updated in Table 5.

[0101] [Table 5] In the example in Figure 15, IAB-Donor-DU2 may select a different egress BH RLC channel, for example, BH RLC Channel #1 may be selected as the egress RLC channel. Alternatively, it may re-select the egress link for this downlink data, for example, selecting the egress link corresponding to Routing ID #2 and IAB-node 5, and then selecting the egress RLC channel for the egress link corresponding to IAB-node 5.

[0102] Figure 16 is a schematic diagram of another example of the routing process of the routing method according to an embodiment of the present invention, showing a case where a donor-CU downlink routing substitution table is configured on the IAB node. In the example of Figure 16, IAB node 4 (IAB-node 4) is an IAB node and IAB node 3 (IAB-node 3) is a child node.

[0103] Table 6 shows examples of routing identifiers in the example shown in Figure 16.

[0104] [Table 6] In Table 6, Routing ID #1, Routing ID #2, Routing ID #3, and Routing ID #6 belong to the donor-CU2 domain, while Routing ID #4 and Routing ID #5 belong to the donor-CU1 domain.

[0105] Table 7 shows an example of the routing table for IAB node 4 in the example shown in Figure 16.

[0106] [Table 7] Table 8 shows an example of the downlink BH RLC mapping table for IAB node 4 in the example shown in Figure 16.

[0107] [Table 8] In the example shown in Figure 16, as shown in Figure 16, IAB-node 4 receives downlink data for the donor-CU1 and donor-CU2 domains, and an F1 connection is established between donor-CU1 and IAB-node 4. Therefore, the first donor-CU of IAB-node 4 is donor-CU1, and the second donor-CU of IAB-node 4 is donor-CU2. At IAB-node 4, it is necessary to replace the routing belonging to the donor-CU2 domain with the routing belonging to the donor-CU1 domain. An example of a donor-CU inter-downlink routing replacement table at IAB-node 4 is shown in Table 9.

[0108] [Table 9] Furthermore, in the example shown in Figure 16, as shown in Figure 16, IAB-node 3 needs to receive downlink data from the donor-CU1 domain and the donor-CU2 domain. Since an F1 connection is established between donor-CU2 and IAB-node 3, the first donor-CU of IAB-node 3 is donor-CU2, and the second donor-CU of IAB-node 3 is donor-CU1. In IAB-node 3, it is necessary to replace the routing belonging to the donor-CU1 domain (routing ID #5) with the routing belonging to the donor-CU2 domain (routing ID #6). An example of a donor-CU inter-downlink routing replacement table in IAB-node 3 is shown in Figure 10.

[0109] [Table 10] As shown in Figure 16, if the buffer for routing ID #6 in IAB-node 3 exceeds a predetermined threshold, since routing ID #6 belongs to the substituted routing ID in the routing table, IAB-node 3 sends a flow control instruction to IAB-node 4 that includes the substituted routing ID (routing ID #5) corresponding to routing ID #6.

[0110] Thus, IAB-node 4 determines that routing ID #5 is congested and that the egress link corresponding to IAB-node 3 is unavailable for routing ID #5. The routing table of IAB-node 4 is updated to Table 11.

[0111] [Table 11] When IAB-node 4 receives downlink data with a header carrying routing ID #3, it determines that routing ID #3 is the replaced routing ID in the Donor-CU downlink routing replacement table. Based on the Donor-CU downlink routing replacement table, it corrects routing ID #3 in the header to the corresponding replaced routing ID (routing ID #5).

[0112] Next, IAB-node 4 selects an egress link based on routing ID #5 and finds a routing configuration where the routing ID matches routing ID #5. However, the egress link corresponding to the next hop address of this routing configuration, IAB-node 3, is not available for routing ID #5. In other words, there are no available egress links for routing ID #5.

[0113] Next, IAB-node 4 checks again whether there is an available egress link for the destination address IAB-node 1 of routing ID #5. If another routing configuration is found with the destination address IAB-node 1, and an egress link corresponding to the next-hop address (IAB-node 2) is available for the routing ID (Routing ID #4) of that routing configuration, IAB-node 4 may select the egress link corresponding to the next-hop address (IAB-node 2) of these two routing configurations as the egress link for the packet.

[0114] Next, IAB-node 4 may select an egress BH RLC channel, check the downlink RLC channel mapping table, and find a matching BH RLC configuration based on the address of the packet's previous hop (IAB-donor DU1), the ingress RLC channel (BH RLC Channel #1), and the selected egress link (IAB-node 2). In this configuration, it may select the egress RLC channel (BH RLC Channel #1) as the egress channel. However, if IAB-node 4 determines that BH RLC Channel #1 is unavailable according to the flow control instructions sent from IAB-node 2, it cannot select BH RLC Channel #1 as the egress RLC channel.

[0115] Furthermore, as shown in Figure 16, IAB-node 4 may forward the flow control instruction to its parent node, IAB donor DU2 (IAB-donor DU 2). Since routing ID #5 included in the received flow control instruction belongs to the replacement routing in the Donor-CU downlink routing replacement table, IAB-node 4 needs to correct routing ID #5 in the flow control instruction to the corresponding replacement routing ID (routing ID #3) before forwarding it to the parent node, and does not need to correct the buffer domains available at the time of forwarding. In this way, IAB-donor DU2 determines that routing ID #3 is in a congested state and that the egress link corresponding to IAB-node 4 is unavailable for routing ID #3.

[0116] Additionally, IAB-donor DU 2 may change its routing table to table 12.

[0117] [Table 12] Figures 13 to 16 above merely illustrate embodiments of the present invention, but the present invention is not limited thereto. For example, the execution order between various steps may be appropriately adjusted, or several other steps may be added, or several steps may be removed. Those skilled in the art can make appropriate modifications based on the above description and are not limited to the depiction in Figures 13 to 16 above.

[0118] The above embodiments are merely illustrative examples of the present invention, and the present invention is not limited thereto. Appropriate modifications may be made based on the above embodiments. For example, each of the above embodiments may be used individually, or one or more of the above embodiments may be used in combination.

[0119] According to the method described in the embodiment of the present invention, it is possible to avoid congested routing and selection of BH RLC channels, thereby mitigating and resolving the problems of congestion and loss of downlink data.

[0120] <Example 2> Embodiments of the present invention provide a routing method for routing uplink data.

[0121] Figure 17 is a schematic diagram of an example of a routing method according to Embodiment 2 of the present invention, described from the perspective of an IAB node in an IAB system, which functions as a parent node. As shown in Figure 17, the method includes the following steps.

[0122] Step 1701: If an IAB node detects that an RLF has occurred on one or more ingress links, it sends RLF instruction information to its child nodes. The RLF instruction information includes a routing identifier in the routing configuration of the IAB node's routing table, in which the egress link corresponding to the next hop address is the link on which the RLF occurred, so that the child nodes route uplink data based on the RLF instruction information.

[0123] In an embodiment of the present invention, when an IAB node (IAB-MT) detects that an RLF has occurred on one or more ingress links, the IAB node (IAB-DU) sends an RLF instruction to each child node corresponding to the IAB node's egress link, including the Routing ID corresponding to the routing configuration in the routing table's routing configuration (BH Routing Configuration) where the link corresponding to all next-hop addresses is the link on which the RLF occurred. In this way, the child node reroutes the data on the link on which the RLF occurred.

[0124] In embodiments of the present invention, substitution routing of one or more second donor-CU domains may be configured for routing of several first donor-CU domains in order to transmit uplink data. If an IAB-node has established dual connections with the first and second donor-CUs, the IAB-node has established an F1 connection with the first donor-CU. Some uplink data needs to be sent via the IAB-node to the parent node of the second donor-CU domain. It needs to be routed by changing some of the routing identifiers of the first donor-CU domain to the routing identifiers of the second donor-CU domain. For example, in Figure 18, routing belonging to the first donor-CU domain (Routing ID #3) needs to be converted to routing of the second donor-CU domain (Routing ID #2) before being sent to the parent node of the second donor-CU domain (IAB-node 2). Therefore, for the IAB-node, a mapping relationship table is constructed from the routing identifier of the first donor-CU domain to the routing identifier of the second donor-CU domain, i.e., an inter-donor-CU uplink routing substitution table.

[0125] Furthermore, within the same donor-CU domain, the IAB-node disconnects the link with the original parent node and establishes a link with a new parent node, for example, switching from one parent node to another, or re-establishing the RRC from one parent node to another. Uplink data needs to be routed to the new donor-DU, but the destination donor-DU in the packet header of the original uplink is different from the new donor-DU. Therefore, to prevent uplink data from being discarded by the new donor-DU, the routing identifier in the packet header needs to be modified to a routing identifier that can be routed to the new donor-DU. For the IAB-node, a mapping relationship table from the original routing ID to the new routing ID, i.e., a donor-DU uplink routing substitution table, needs to be configured.

[0126] Furthermore, according to the inventors of the present invention, if an IAB node has dual connections established with two Donor-CUs, uplink data needs to be routed to different donor-CU domains, and routing to different donor-CU domains may conflict. For example, in Figure 18, Routing ID #1 and Routing ID #2 may be the same. For uplink routing in an IAB node, it is necessary to configure routing tables for different donor-CU domains for the IAB node, namely a first routing table for the first donor-CU domain and a second routing table for the second donor-CU domain.

[0127] Furthermore, according to the inventors of the present invention, when an IAB node has a dual connection established with two Donor-CUs, if the link where the RLF occurred is an ingress link corresponding to the second donor-CU, it can be seen that the second donor-CU domain routing, whose next hop is the parent node corresponding to the second donor-CU, is unavailable, and the first donor-CU domain routing, which was replaced by the second donor-CU domain routing, is also unavailable at the child node. Therefore, the IAB node needs to send RLF instruction information including the first donor-CU domain routing to the child node. If the link where the RLF occurred is an ingress link corresponding to the first donor-CU, it can be seen that the first donor-CU domain routing, whose next hop is the parent node corresponding to the first donor-CU, is unavailable, and this routing is also unavailable at the child node. Therefore, the IAB node only needs to send RLF instruction information including the first donor-CU domain routing to the child node. In this way, the child node can understand the availability status of routing.

[0128] In some embodiments of the present invention, if an IAB node has a donor-CU uplink routing substitution table configured and it is determined that the link where the RLF occurred is an ingress link corresponding to a second donor-CU, the IAB node determines, based on the second routing table (routing table for the second donor-CU topology domain), that the egress link corresponding to the next hop address is the third routing identifier of the ingress link corresponding to the second donor-CU. Based on the donor-CU uplink routing substitution table, the IAB node determines a fourth routing identifier (belonging to the first donor-CU topology domain) that needs to be substituted for the third routing identifier (belonging to the second donor-CU topology domain). The IAB node sends RLF instruction information to the child node. The RLF instruction information includes the fourth routing identifier.

[0129] In other words, if, based on the second routing table, the routing ID corresponding to the link where the RLF occurred is determined to be the replacement routing ID in the donor-CU uplink routing replacement table, the replacement routing ID is unavailable at the IAB node, meaning it is unavailable at the child node as well. Since the replacement routing ID at the IAB node is not known by the IAB node, the IAB node needs to notify the child node of the status of the replaced routing ID. Therefore, the IAB node searches for the replaced routing ID of the replacement routing ID based on the donor-CU uplink routing replacement table and sends the replaced routing ID to the child node in the RLF instruction.

[0130] Taking Figure 18 as an example, if IAB-node 3 detects that the link where the RLF occurred is the parent node IAB-node 2 corresponding to the second donor-CU, then Routing ID #2, whose next hop is IAB-node 2, is unavailable. From the donor-CU uplink routing substitution table, it can be seen that Routing ID #2 needs to substitute for routing Routing ID #3 of the first donor-CU domain. In other words, Routing ID #3 is also unavailable at IAB-node 4. IAB-node 3 needs to send RLF instruction information including Routing ID #3 to IAB-node 4 to make IAB-node 4 aware that Routing ID #3 is unavailable.

[0131] In another embodiment of the present invention, if it is determined that the IAB node does not have a donor-CU uplink routing substitution table configured, or if the link on which the RLF occurred is an ingress link corresponding to a first donor-CU and the IAB node and the first donor-CU have an F1 connection, the IAB node determines, based on a first routing table (a routing table for the first donor-CU topology domain), that the egress link corresponding to the next hop address is the third routing identifier of the ingress link corresponding to the first donor-CU. The IAB node sends RLF instruction information to the child node. The RLF instruction information includes the third routing identifier (belonging to the first donor-CU topology domain).

[0132] Figure 19 is a schematic diagram of another example of the routing method according to an embodiment of the present invention, described from the perspective of a child node of an IAB node in an IAB system, which is also an IAB node in the IAB system. To distinguish it from the embodiment in Figure 17, in the embodiment in Figure 19, the node is referred to as a "child node". Here, redundant explanations of content similar to that in the embodiment in Figure 17 are omitted.

[0133] As shown in Figure 19, the method includes the following steps.

[0134] Step 1901: The child node receives RLF instruction information from the IAB node. The RLF instruction information includes a routing identifier, which indicates that the link corresponding to the next hop address is the link where the RLF occurred.

[0135] Step 1902: The child node routes the uplink data based on the RLF instruction information.

[0136] In some embodiments, in step 1902, the child node determines whether routing is available based on the RLF instruction information and routes the uplink data based on whether routing is available. Here, the child node determines, based on the RLF instruction information, that the link corresponding to the IAB node is not available for routing. That is, when the child node (IAB-MT) receives an RLF instruction containing a Routing ID, it determines that the egress link corresponding to the IAB node is unavailable for the routing (the routing corresponding to the Routing ID contained in the RLF instruction) and re-selects routing for the data (uplink data) of the Routing ID.

[0137] For example, if the link corresponding to an IAB node is an ingress link corresponding to the first donor-CU, the child node determines that the link corresponding to the IAB node is not available for routing in the first routing table. The first routing table is the routing table for the first donor-CU topology domain. Here, the child node may change the availability of routing in the first routing table to unavailable (NO).

[0138] Furthermore, for example, if the link corresponding to an IAB node is an ingress link corresponding to a second donor-CU, the child node determines that the link corresponding to the IAB node is not available for routing in the second routing table. The second routing table is the routing table for the second donor-CU topology domain. Here, the child node may change the availability of routing in the second routing table to unavailable (NO).

[0139] In embodiments of the present invention, routing uplink data based on whether routing is available may include selecting an egress link for uplink data based on whether routing is available. That is, if a child node (IAB-MT) receives an RLF instruction from an IAB node that includes a Routing ID, it may determine that the egress link corresponding to the IAB node is unavailable for that Routing ID. In this way, when selecting routing for data (uplink data) at that Routing ID, the child node does not select this egress link.

[0140] In some embodiments, if a donor-CU uplink routing substitution table is configured in a child node, and it is determined that a first routing identifier in the BAP header of the uplink data (belonging to a first donor-CU topology domain) belongs to a substituted routing identifier in the donor-CU uplink routing substitution table, the child node replaces the first routing identifier in the BAP header of the uplink data with the corresponding second routing identifier (belonging to a second donor-CU topology domain) based on the donor-CU uplink routing substitution table. Subsequently, it is determined whether the child node's second routing table contains a routing configuration that satisfies the first condition.

[0141] If the child node's second routing table contains a routing configuration that satisfies the first condition, the child node will use the egress link corresponding to the next-hop address in the routing configuration as the first egress link for the uplink data. The first condition means that the routing identifier in the routing configuration matches the second routing identifier, and the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0142] In the above example, if the child node's second routing table does not contain a routing configuration that satisfies the first condition, the child node determines whether or not there is a routing configuration in its second routing table that satisfies the third condition. If there is a routing configuration in the child node's second routing table that satisfies the third condition, the egress link corresponding to the next-hop address in the routing configuration is used as the egress link for the data packets of the uplink data. The third condition means that the destination BAP address of the routing identifier in the routing configuration matches the destination BAP address of the second routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0143] In the above example, if the child node's second routing table does not contain a routing configuration that satisfies the third condition, the child node determines whether or not a second donor-CU routing substitution table is configured in the child node. If the child node has a second donor-CU routing substitution table configured, and the second routing identifier belongs to a substituted routing identifier in the second donor-CU routing substitution table and is substituted with the fifth routing identifier, the child node determines whether or not there is a routing configuration in its second routing table that satisfies the fifth condition.

[0144] If the child node's second routing table contains a routing configuration that satisfies the fifth condition, the child node, based on the second donor-DU routing substitution table, changes the second routing identifier in the header of the uplink data packet to the corresponding fifth routing identifier, and sets the egress link corresponding to the next-hop address in the routing configuration as the egress link for the uplink data packet. The fifth condition includes that the routing identifier in the routing configuration matches the fifth routing identifier, or that the destination address in the routing configuration matches the destination address of the fifth routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0145] In the above example, if the child node's second routing table does not contain a routing configuration that satisfies the fifth condition, it means that there are no available egress links to the second donor-CU domain, and it is determined whether the child node has a first routing table configured. If the child node has a first routing table configured, it is determined whether the child node's first routing table contains a routing configuration that satisfies the seventh condition.

[0146] If the child node's first routing table contains a routing configuration that satisfies the seventh condition, the child node changes the first routing identifier in the header of the uplink data packet to the seventh routing identifier and sets the egress link corresponding to the next-hop address in the routing configuration as the egress link for the uplink data packet. The seventh condition includes that the routing identifier in the routing configuration matches the seventh routing identifier, or that the destination address in the routing configuration matches the destination address of the seventh routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0147] In some other embodiments, if it is determined that a donor-CU uplink routing substitution table is not configured for a child node, or if a first routing identifier in the uplink data header (belonging to a first donor-CU topology domain) does not belong to a substituted routing identifier in the donor-CU uplink routing substitution table, it is determined whether the child node's first routing table has a routing configuration that satisfies a second condition.

[0148] When the first routing table of a child node contains a routing configuration that satisfies the second condition, the egress link corresponding to the next-hop address in the routing configuration is set as the first egress link in the downlink data. The second condition means that the routing identifier in the routing configuration matches the first routing identifier, and the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0149] In other words, when a child node receives uplink data, it may check its routing table and determine whether there is an available egress link for the routing ID in the packet header. If there is a routing configuration where the routing ID matches the routing ID in the packet header (both the destination BAP address and path ID match), and an egress link corresponding to the next-hop address in this routing configuration is available for this routing ID, the child node selects the egress link corresponding to the next-hop address in this routing configuration as the packet's egress link.

[0150] In the above example, if the child node's first routing table does not contain a routing configuration that satisfies the second condition, it is determined whether the child node's first routing table contains a routing configuration that satisfies the fourth condition. If the child node's first routing table contains a routing configuration that satisfies the fourth condition, the egress link corresponding to the next-hop address in the routing configuration is used as the egress link for the uplink data packet. The fourth condition means that the destination BAP address of the routing identifier in the routing configuration matches the destination BAP address of the first routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0151] In other words, if no suitable egress link is found according to the second condition, it means that there are no available egress links for the routing ID in this packet header. The child node may also check whether there is any available routing for the destination BAP address in this packet header. If there is a routing configuration where the destination BAP address matches the destination BAP address in the packet header, and an egress link corresponding to the next hop address of this routing configuration is available for the routing ID of this routing configuration, the egress link corresponding to the next hop address of this routing configuration is selected as the egress link for the packet.

[0152] In the above embodiment, if the child node's first routing table does not contain a routing configuration that satisfies the fourth condition, it is determined whether the child node has a first donor-CU routing substitution table configured. If the child node has a first donor-CU routing substitution table configured, and the first routing identifier belongs to a substituted routing identifier in the first donor-CU routing substitution table and is substituted with the sixth routing identifier, it is determined whether the child node's first routing table contains a routing configuration that satisfies the sixth condition.

[0153] If the child node's first routing table contains a routing configuration that satisfies the sixth condition, the child node modifies the first routing identifier in the header of the uplink data packet to the corresponding sixth routing identifier based on the first donor-DU routing substitution table, and sets the egress link corresponding to the next-hop address in the routing configuration as the egress link for the uplink data packet. The sixth condition includes that the routing identifier in the routing configuration matches the sixth routing identifier, or that the destination address in the routing configuration matches the destination address of the sixth routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0154] In other words, if a suitable egress link is not found according to the fourth condition, it means that there is no available egress link for the destination address of this data. The child node may further check whether there is available routing for other destination addresses. If there is a routing configuration in which an egress link corresponding to the next hop is available for the routing ID of this routing configuration, the egress link corresponding to the next hop address of this routing configuration is selected as the egress link for the packet. The destination address in the thus selected routing configuration will differ from the destination address in the packet header, and in order to prevent this uplink data from being discarded by the IAB-donor DU, the destination address in the packet header must be corrected to the destination address in this routing configuration, and the path identifier in the packet header must be corrected to the path identifier of this routing configuration.

[0155] In the above example, if the child node's first routing table does not contain a routing configuration that satisfies the sixth condition, it is determined whether the child node has a second routing table configured. If the child node has a second routing table configured, it is determined whether the child node's second routing table contains a routing configuration that satisfies the eighth condition.

[0156] If the child node's second routing table contains a routing configuration that satisfies the eighth condition, the child node changes the first routing identifier in the header of the uplink data packet to the eighth routing identifier and sets the egress link corresponding to the next-hop address in the routing configuration as the egress link for the uplink data packet. The eighth condition includes that the routing identifier in the routing configuration matches the eighth routing identifier, or that the destination address in the routing configuration matches the destination address of the eighth routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0157] In other words, if no suitable egress link is found according to the eighth condition, it means that there are no available egress links for the donor-CU domain to which this first routing belongs. The child node may then check again to see if there are any available routes for another donor-CU domain.

[0158] In the above embodiment, if a suitable egress link for the uplink data is not found by any of the methods according to the above embodiment, the child node may discard the uplink data or stop transmitting the uplink data.

[0159] The above exemplifies the process by which a child node selects an egress link for uplink data, with reference to various embodiments. However, the present invention is not limited thereto, and appropriate modifications may be made based on the above embodiments. For example, each of the above embodiments may be used individually, or one or more of the above embodiments may be used in combination.

[0160] In the above embodiment, after the egress link is selected, the child node may select an egress BH RLC channel for the uplink data. The present invention is not limited to a specific selection method, and conventional methods or other applicable methods may be employed.

[0161] In the above embodiment, the child node may continue to forward the above RLF instruction to its child nodes (if any). That is, the child node may forward the RLF instruction information to its child nodes.

[0162] According to the inventors' findings, when an IAB node has a dual connection with two Donor-CUs, and receives RLF instruction information from the parent node corresponding to the second donor-CU, and the RLF instruction information includes routing for the second donor-CU domain, then the routing for the second donor-CU domain is unavailable. Furthermore, it is understood that the first donor-CU domain routing, which has been replaced by the second donor-CU domain routing, is also unavailable to the child node. Therefore, the IAB node needs to send RLF instruction information including this first donor-CU domain routing to the child node. When the IAB node receives RLF instruction information including the first donor-CU domain routing from the parent node corresponding to the first donor-CU, it is understood that the routing is unavailable and therefore unavailable to the child node. Therefore, the IAB node only needs to send RLF instruction information including the first donor-CU domain routing to the child node. In this way, the child node is made aware of the availability status of routing.

[0163] In some embodiments, a child node is configured with a donor-CU uplink routing substitution table, and RLF instruction information is received from an ingress link corresponding to a second donor-CU. If the RLF instruction information includes a third routing identifier (belonging to the second donor-CU topology domain), the child node determines, based on the donor-CU uplink routing substitution table, a fourth routing identifier (belonging to the first donor-CU topology domain) that needs to be replaced by the third routing identifier. The child node then sends the RLF instruction information to its own child node, and the RLF instruction information includes the fourth routing identifier. That is, if the RLF instruction received by the child node contains a replacement routing identifier for that child node, the routing identifier in the RLF instruction needs to be modified to the corresponding replacement routing identifier and forwarded to the child node.

[0164] In some other embodiments, if it is determined that a donor-CU uplink routing substitution table is not configured on a child node, or if the RLF directive information is received from an ingress link corresponding to the first donor-CU and the RLF directive information includes a third routing identifier (belonging to the first donor-CU topology domain), the RLF directive information is sent to its child node. The RLF directive information includes a third routing identifier.

[0165] Taking Figure 18 as an example, when IAB-node 3 receives RLF instruction information including Routing ID#2 from its parent node IAB-node 2, which corresponds to the second donor-CU, it can be seen that Routing ID#2 is unavailable. From the routing substitution relationship, it can be seen that Routing ID#2 needs to substitute for routing Routing ID#3 in the first donor-CU domain, which means that Routing ID#3 is also unavailable at IAB-node 4. IAB-node 3 needs to send RLF instruction information including Routing ID#3 to IAB-node 4 to let IAB-node 4 know that Routing ID#3 is unavailable.

[0166] The following describes a routing method according to an embodiment of the present invention, with reference to specific examples.

[0167] Figure 20 is a schematic diagram of another example of routing relationships for IAB nodes, showing a case where a donor-CU uplink routing substitution table is not configured for the IAB node. In the example in Figure 20, IAB node 3 (IAB-node 3) is the IAB node and IAB node 4 (IAB-node 4) is the child node.

[0168] Table 13 shows an example of routing identifiers in the example shown in Figure 20.

[0169] [Table 13] Table 14 shows an example of the routing table (i.e., the first routing table) for IAB node 3 in the example shown in Figure 20.

[0170] [Table 14] Table 15 shows an example of the routing table (i.e., the first routing table) for IAB node 4 in the example shown in Figure 20.

[0171] [Table 15] Table 16 shows an example of the donor-DU routing substitution table for IAB node 4 in the example shown in Figure 20 (i.e., the first donor-DU routing substitution table).

[0172] [Table 16] In the example in Figure 20, IAB-node 3 has established dual wireless links with IAB-node 1 and IAB-node 2. If IAB-node 3 detects that an RLF has occurred on the wireless link corresponding to IAB-node 1, then no RLF has occurred on the wireless link corresponding to IAB-node 2. IAB-node 3 may also instruct IAB-node 4 to include Routing ID #1 in the RLF indication, i.e., Routing ID #1.

[0173] When IAB-node 4 receives an RLF indication containing Routing ID #1 from the ingress link corresponding to IAB-node 3, IAB-node 4 determines that the link corresponding to IAB-node 3 is unavailable for Routing ID #1 (however, the link corresponding to IAB-node 3 is available for Routing ID #2). The routing table on IAB-node 4 is updated to Table 17.

[0174] [Table 17] When IAB-node 4 receives uplink data with the header containing Rouging ID #1, it first checks its routing table to see if there is an available route for routing ID #1. If a routing configuration is found where the routing ID matches routing ID #1, it is determined that the egress link corresponding to the next hop address IAB-node 3 in this routing configuration is not available for routing ID #1. In other words, there is no available egress link for routing ID #1.

[0175] Next, IAB-node 4 checks whether there is an available egress link for the destination address IAB-donor DU1 in the header. If the destination addresses for Routing ID #2 and Routing ID #3 are IAB-donor DU1, and it is determined that egress links corresponding to the next-hop addresses (IAB-node 3 and IAB-node 6) are available for Routing ID #2 and Routing ID #3 respectively, IAB-node 4 may select the egress link corresponding to the next-hop address (IAB-node 3 and IAB-node 6) for Routing ID #2 or Routing ID #3 as the egress link for the packet.

[0176] Furthermore, if the egress links corresponding to IAB-node 3 and IAB-node 6 are unavailable for Routing ID #2 and Routing ID #3, respectively, for example, if IAB-node 4 receives an RLF indication from IAB-node 6 that includes Routing ID #3, it will consider the egress link corresponding to IAB-node 6 to be unavailable for Routing ID #3. In other words, it means that there are no available egress links for the destination address of Routing ID #1. IAB-node 4 will then re-check whether Routing ID #1 can be replaced by routing to a different destination address. IAB-node 4 checks the donor-DU routing substitution table and, if Routing ID #4 can substitute for Routing ID #1 and an egress link corresponding to the next-hop address (IAB-node 6) is available for Routing ID #4, IAB-node 4 may select the egress link corresponding to the next-hop address (IAB-node 6) for Routing ID #4 as the packet's egress link. Since the destination address of routing ID #4 (IAB-donor DU2) is different from the destination address in the packet header (IAB-donor DU1), it is necessary to correct the destination address in the packet header to IAB-donor DU2, or correct routing ID #1 in the packet header to routing ID #4, so that this uplink data is not discarded by IAB-donor DU2.

[0177] Figure 21 is a schematic diagram of another example of routing relationships for IAB nodes, showing the case where a donor-CU uplink routing substitution table is configured for the IAB node. In the example in Figure 21, IAB node 6 (IAB-node 6) is the IAB node and IAB node 4 (IAB-node 4) is the child node.

[0178] Table 18 shows an example of routing identifiers in the example shown in Figure 21. Here, Routing ID #1, Routing ID #2, Routing ID #3, Routing ID #6, and Routing ID #7 belong to the donor-CU1 domain, while Routing ID #4 and Routing ID #5 belong to the donor-CU2 domain.

[0179] [Table 18] In the example in Figure 21, IAB-node 4 needs to send data to both the donor-CU1 domain and the donor-CU2 domain. Donor-CU1 establishes an F1 connection with IAB-node 4, and the first donor-CU of IAB-node 4 is donor-CU1, while the second donor-CU is donor-CU2. At IAB-node 4, routing belonging to the donor-CU1 domain (Routing ID #6 and Routing ID #7) needs to be replaced with routing belonging to the donor-CU2 domain (Routing ID #4 and Routing ID #5). Table 19 shows the donor-CU inter-uplink routing replacement table at IAB-node 4.

[0180] [Table 19] Table 20 is an example of the first routing table for the donor-CU1 domain of IAB node 4.

[0181] [Table 20] Table 21 is an example of a second routing table for the donor-CU2 domain of IAB node 4.

[0182] [Table 21] In the example in Figure 21, IAB-node 6 needs to send data to both the donor-CU1 and donor-CU2 domains simultaneously. Donor-CU2 establishes an F1 connection with IAB-node 6, and the first donor-CU of IAB-node 6 is donor-CU2, while the second donor-CU is donor-CU1. IAB-node 6 needs to replace the routing belonging to the donor-CU2 domain (Routing ID #5) with the routing belonging to the donor-CU1 domain (Routing ID #3). Table 22 shows the donor-CU inter-uplink routing replacement table for IAB-node 6.

[0183] [Table 22] Table 23 is an example of the first routing table for the donor-CU2 domain on IAB node 6.

[0184] [Table 23] Table 24 is an example of a second routing table for the donor-CU1 domain on IAB node 6.

[0185] [Table 24] In the example in Figure 21, IAB-node 6 has established dual wireless links with IAB-node 2 and IAB-node 5. If IAB-node 6 (IAB-MT) detects that an RLF has occurred on the wireless link corresponding to IAB-node 2, and no RLF has occurred on the ingress link corresponding to IAB-node 5, it determines that Routing ID #3, whose next-hop address is IAB-node 2, is unavailable. IAB-node 6 (IAB-DU) may also instruct IAB-node 4 (IAB-MT) to use Routing ID #3, whose next-hop address is IAB-node 2. According to IAB-node 6's second routing table, the next-hop address for routing ID #3 is IAB-node 2. Since routing ID #3 belongs to the replacement routing ID in the donor-CU uplink routing replacement table, IAB-node 6 must include the replacement routing ID (routing ID #5) corresponding to routing ID #3 when sending an RLF instruction to IAB-node 4. Thus, IAB-node 4 determines that routing ID #5 is unavailable, that is, it determines that the egress link corresponding to IAB-node 6 is unavailable for routing ID #5.

[0186] When IAB-node 4 receives an RLF indication containing Routing ID #5 from the ingress link of IAB-node 6, it is determined that it was received from the ingress link of the second donor-CU domain, and IAB-node 4 determines that the link corresponding to IAB-node 6 is unavailable for Routing ID #5 in the second routing table (however, the link corresponding to IAB-node 4 is available for Routing ID #4). The second routing table on IAB-node 4 is updated to Table 25.

[0187] [Table 25] When IAB-node 4 receives uplink data with a header carrying Rouging ID #6, it determines that routing ID #6 is the replaced routing ID in the donor-CU uplink routing replacement table. According to the donor-CU uplink routing replacement table, it modifies routing ID #6 in the header to the corresponding replaced routing ID (routing ID #5).

[0188] Subsequently, IAB-node 4 selects an egress link based on routing ID #5 and checks the second routing table to find a routing configuration where the routing ID matches routing ID #5. However, the egress link corresponding to the next hop address IAB-node 6 in this routing configuration is not available for routing ID #5. In other words, there are no available egress links for routing ID #5.

[0189] Subsequently, IAB-node 4 checks again whether there is an available egress link for the destination address IAB-donor DU2 in the header. If it is determined that the destination address for routing ID #4 is also IAB-donor DU2, and that an egress link corresponding to the next-hop address (IAB-node 6) for routing ID #4 is available for routing ID #4, then IAB-node 4 may select the egress link corresponding to the next-hop address (IAB-node 6) for routing ID #4 as the egress link for the packet.

[0190] Furthermore, if the egress link of IAB-node 6 is also unavailable for Routing ID #4, for example, if IAB-node 4 receives an RLF indication from IAB-node 6 that includes Routing ID #4, it will consider the egress link corresponding to IAB-node 6 to be unavailable for Routing ID #4. In other words, it means that there are no available egress links to the donor-CU2 domain. IAB-node 4 will then re-check whether there are any available routes to the donor-CU1 domain. If the first routing table of IAB-node 4 indicates that the destination addresses for Routing ID #1 and Routing ID #2 are IAB-donor DU1, and that egress links corresponding to the next-hop address (IAB-node 3) are available for Routing ID #1 and Routing ID #2 respectively, then IAB-node 4 may select the egress link corresponding to the next-hop address (IAB-node 4) for Routing ID #1 or Routing ID #2 as the packet's egress link. To prevent this uplink data from being discarded by IAB-donor DU1, the destination address in the header must be changed to IAB-donor DU1, or routing ID #5 in the header must be changed to routing ID #1 or routing ID #2.

[0191] Figures 17 to 21 above merely illustrate embodiments of the present invention, but the present invention is not limited thereto. For example, the execution order between various steps may be appropriately adjusted, or several other steps may be added or several steps removed. Those skilled in the art can make appropriate modifications based on the above description and are not limited to the description in Figures 17 to 21 above.

[0192] The above embodiments are merely illustrative examples of the present invention, and the present invention is not limited thereto. Appropriate modifications may be made based on the above embodiments. For example, each of the above embodiments may be used individually, or one or more of the above embodiments may be used in combination.

[0193] According to the method described in the embodiment of the present invention, it is possible to avoid congested routing and selection of BH RLC channels, thereby mitigating and resolving the problems of congestion and loss of downlink data.

[0194] <Example 3> An embodiment of the present invention provides a routing device that routes downlink data.

[0195] Figure 22 is a schematic diagram of an example of a routing device according to an embodiment of the present invention. This device may be, for example, an IAB node in an IAB system, or a component configured in an IAB node. The IAB node functions as a parent node. Here, the implementation principle of the routing device according to an embodiment of the present invention is the same as that of the IAB node embodiment in Figure 12 in Embodiment 1, and redundant explanations of similar content will be omitted.

[0196] As shown in Figure 22, the routing device 2200 according to an embodiment of the present invention includes the following parts.

[0197] The receiving unit 2201 receives flow control instruction information from a child node regarding the BH RLC channel and / or routing. The flow control instruction information includes the available buffer size and the identifier of the BH RLC channel, and / or the available buffer size and the identifier of the routing.

[0198] The processing unit 2202 routes the downlink data based on the available buffer size.

[0199] In some embodiments, the processing unit 2202 routing downlink data based on the buffer size available to the IAB node includes the processing unit 2202 determining whether the BH RLC channel and / or routing is congested and available based on the buffer size available to the IAB node, and routing downlink data based on whether the BH RLC channel and / or routing is available.

[0200] In some embodiments, if the available buffer size for routing is smaller than a first buffer threshold, the processing unit 2202 determines that routing is congested and that the link corresponding to the child node is not available for routing; or, if the available buffer size for the BH RLC channel is smaller than a second buffer threshold, the processing unit 2202 determines that the BH RLC channel is congested and that the BH RLC channel for the link corresponding to the child node is not available.

[0201] In embodiments of the present invention, routing downlink data based on whether routing is available by the processing unit 2202 includes selecting an egress link for the downlink data based on whether routing is available.

[0202] In embodiments of the present invention, if an IAB node has a donor-CU downlink routing substitution table configured and it is determined that the downlink data is from an ingress link corresponding to a second donor-CU, the processing unit 2202 replaces the first routing identifier in the BAP header of the downlink data with the corresponding second routing identifier based on the donor-CU downlink routing substitution table. Here, the first routing identifier belongs to the second donor-CU topology domain, and the second routing identifier belongs to the first donor-CU topology domain. If the routing table of the IAB node has a routing configuration that satisfies the second condition, the processing unit 2202 sets the egress link corresponding to the next-hop address in the routing configuration as the first egress link of the downlink data. The second condition means that the routing identifier in the routing configuration matches the second routing identifier, and the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0203] In the above embodiment, the processing unit 2202 replaces the first routing identifier in the BAP header of the downlink data with the corresponding second routing identifier, and then passes the downlink data to the upper layer of the IAB node if the destination BAP address of the second routing identifier is the BAP address configured for the IAB node by the first donor-CU.

[0204] In some embodiments, if an IAB node has a donor-CU downlink routing substitution table configured and it is determined that the downlink data is from an ingress link corresponding to a second donor-CU, then the processing unit 2202 passes the downlink data to the upper layer of the IAB node if the destination BAP address of the first routing identifier in the BAP header of the downlink data is the BAP address configured for the IAB node by the second donor-CU.

[0205] In some embodiments, if it is determined that the IAB node does not have a donor-CU downlink routing substitution table configured, or if the IAB node has a donor-CU downlink routing substitution table configured and it is determined that the downlink data is from an ingress link corresponding to a first donor-CU, and the first routing identifier in the header of the downlink data belongs to the first donor-CU topology domain, then if the routing table of the IAB node has a routing configuration that satisfies the first condition, the processing unit 2202 sets the egress link corresponding to the next hop address in the routing configuration as the first egress link of the downlink data. The first condition means that the routing identifier in the routing configuration matches the first routing identifier, and the egress link corresponding to the next hop address in the routing configuration is available for routing in the routing configuration.

[0206] In some embodiments, if the routing table of an IAB node does not contain a routing configuration that satisfies the first condition, the processing unit 2202 determines whether the routing table of the IAB node contains a routing configuration that satisfies the third condition. If the routing table of the IAB node contains a routing configuration that satisfies the third condition, the processing unit 2202 sets the egress link corresponding to the next-hop address in the routing configuration as the first egress link for the downlink data. The third condition means that the destination BAP address of the routing identifier in the routing configuration matches the destination BAP address of the first routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the said routing configuration.

[0207] In some embodiments, if it is determined that the IAB node does not have a donor-CU downlink routing substitution table configured, or if the IAB node has a donor-CU downlink routing substitution table configured and it is determined that the downlink data is from an ingress link corresponding to a first donor-CU, the processing unit 2202 passes the downlink data to the upper layer of the IAB node if the destination BAP address of the first routing identifier in the BAP header of the downlink data is the BAP address configured for the IAB node by the first donor-CU.

[0208] In embodiments of the present invention, routing downlink data based on whether routing is available by the processing unit 2202 includes selecting an egress BH RLC channel for the downlink data based on whether a BH RLC channel is available.

[0209] In some embodiments, the IAB node is the donor node of the IAB system. The processing unit 2202 selecting an egress BH RLC channel for downlink data based on whether a BH RLC channel is available includes the following:

[0210] If the RLC channel mapping table of the IAB node contains a BH RLC channel configuration that satisfies the fourth condition, the processing unit 2202 selects the egress BH RLC channel in the BH RLC channel configuration as the egress BH RLC channel for the downlink data. The fourth condition means that the destination IP address and DSCP in the BH RLC channel configuration match the destination IP address and DSCP in the IP header of the downlink data, the egress link corresponding to the next hop address in the BH RLC channel configuration matches the first egress link in the downlink data, and the egress BH RLC channel in the BH RLC channel configuration is available.

[0211] In the above embodiment, in one aspect, if there is no BH RLC channel configuration in the IAB node's RLC channel mapping table that satisfies the fourth condition, the processing unit 2202 selects an available egress BH RLC channel of the first egress link as the egress BH RLC channel for downlink data. If there is no available BH RLC channel on the first egress link, the processing unit 2202 selects a second egress link that is available for downlink data.

[0212] In the above embodiment, in another embodiment, if there is no BH RLC channel configuration in the IAB node's RLC channel mapping table that satisfies the fourth condition, the processing unit 2202 selects a second egress link available for downlink data. If there is no second egress link available, the processing unit 2202 selects an available egress BH RLC channel in the first egress link as the egress BH RLC channel for downlink data.

[0213] In some other embodiments, the IAB node is an intermediate node in the IAB system. The processing unit 2202 selecting an egress BH RLC channel for downlink data based on whether a BH RLC channel is available includes the following:

[0214] If the RLC channel mapping table of the IAB node contains a BH RLC channel configuration that satisfies the fifth condition, the processing unit 2202 selects the egress BH RLC channel in the BH RLC channel configuration as the egress BH RLC channel for the downlink data. The fifth condition means that the address of the previous hop and the ingress RLC channel ID in the BH RLC channel configuration match the downlink data, the egress link corresponding to the address of the next hop in the BH RLC channel configuration matches the first egress link in the downlink data, and the egress BH RLC channel in the BH RLC channel configuration is available.

[0215] In the above embodiment, in one aspect, if there is no BH RLC channel configuration in the IAB node's RLC channel mapping table that satisfies the fifth condition, the processing unit 2202 selects an available egress BH RLC channel of the first egress link as the egress BH RLC channel for downlink data. If there is no available BH RLC channel on the first egress link, the processing unit 2202 selects a second egress link that is available for downlink data.

[0216] In the above embodiment, in another embodiment, if there is no BH RLC channel configuration in the IAB node's RLC channel mapping table that satisfies the fifth condition, the processing unit 2202 selects a second egress link available for downlink data. If there is no second egress link available, the processing unit 2202 selects an available egress BH RLC channel of the first egress link as the egress BH RLC channel for downlink data.

[0217] In embodiments of the present invention, as shown in Figure 22, the routing device 2200 may further include the following parts.

[0218] The transmission unit 2203 transfers the flow control instruction information to the parent node of the IAB node.

[0219] In some embodiments, a donor-CU downlink routing substitution table is configured on the IAB node, and if it is determined that a third routing identifier included in the flow control instruction information belongs to a substitution routing identifier in the donor-CU downlink routing substitution table, the transmission unit 2203 changes the third routing identifier in the flow control instruction information to the corresponding fourth routing identifier based on the donor-CU downlink routing substitution table, and transmits the flow control instruction information to the egress link corresponding to the second donor-CU. Here, the third routing identifier belongs to the first donor-CU topology domain, and the fourth routing identifier belongs to the second donor-CU topology domain.

[0220] In some other embodiments, if it is determined that the IAB node does not have a donor-CU downlink routing substitution table configured, or if it is determined that the third routing identifier included in the flow control instruction information does not belong to the substitution routing identifier in the donor-CU downlink routing substitution table, the transmission unit 2203 transmits the flow control instruction information including the third routing identifier to the egress link corresponding to the first donor-CU. Here, the third routing identifier belongs to the first donor-CU topology domain.

[0221] Figure 23 is a schematic diagram of another example of a routing device according to an embodiment of the present invention. The device may be, for example, an IAB node in an IAB system, or a component configured in an IAB node. The IAB node functions as a child node. Here, the implementation principle of the routing device according to an embodiment of the present invention is the same as the child node embodiment in Figure 14A in Embodiment 1, and redundant explanations of similar content will be omitted.

[0222] As shown in Figure 23, the routing device 2300 according to an embodiment of the present invention includes the following parts.

[0223] The transmitting unit 2301 transmits flow control instruction information based on the BH RLC channel to the IAB node (the parent node of the child node) when the BH RLC channel buffer of the child node exceeds a third buffer threshold. Here, the flow control instruction information includes the available buffer size for the BH RLC channel and the identifier of the BH RLC channel, so that the IAB node routes downlink data based on the available buffer size.

[0224] Figure 24 is a schematic diagram of another example of a routing device according to an embodiment of the present invention. The device may be, for example, an IAB node in an IAB system, or a component configured in an IAB node. The IAB node functions as a child node. Here, the implementation principle of the routing device according to an embodiment of the present invention is the same as the child node embodiment in Figure 14B in Embodiment 1, and redundant explanations of similar content will be omitted.

[0225] As shown in Figure 24, the routing device 2400 according to an embodiment of the present invention includes the following parts.

[0226] The transmitting unit 2401 transmits routing-based flow control instruction information to the IAB node (the parent node of the child node) if the buffer for the fifth routing of the child node exceeds the fourth buffer threshold. Here, the flow control instruction information includes the available buffer size and the fifth routing identifier for the fifth routing, so that the IAB node routes downlink data based on the available buffer size.

[0227] In some embodiments, if a donor-CU downlink routing substitution table is configured in a child node, and it is determined that the fifth routing identifier belongs to a substitution routing identifier in the donor-CU downlink routing substitution table, the transmission unit 2401 includes the sixth routing identifier corresponding to the fifth routing identifier in the donor-CU downlink routing substitution table in the flow control instruction information and transmits it to the egress link corresponding to the second donor-CU. Here, the fifth routing identifier belongs to the first donor-CU topology domain, and the sixth routing identifier belongs to the second donor-CU topology domain.

[0228] In some embodiments, if it is determined that a donor-CU downlink routing substitution table is not configured for a child node, or if it is determined that a fifth routing identifier included in the flow control instruction information does not belong to a substitution routing identifier in the donor-CU downlink routing substitution table, the transmission unit 2401 transmits flow control instruction information including the fifth routing identifier to the egress link corresponding to the first donor-CU. Here, the fifth routing identifier belongs to the first donor-CU topology domain.

[0229] Although the above description only concerns components or modules related to the present invention, the present invention is not limited thereto. The routing devices 2200, 2300, and 2400 according to embodiments of the present invention may further include other components or modules. For specific details of these components or modules, refer to related technologies.

[0230] Furthermore, for the sake of convenience in explanation, FIGS. 22 to 24 only exemplarily show the connection relationships or signal directions between various components or modules, but it is obvious to those skilled in the art that various related technologies such as bus connections can be used. The above various components or modules may be implemented by hardware devices such as processors, memories, transmitters, and receivers, and the present invention is not limited thereto.

[0231] According to an embodiment of the present invention, it is possible to avoid the convergent routing and the selection of the BH RLC channel, and reduce and solve the problems of downlink data convergence and loss.

[0232] <Example 4> An embodiment of the present invention provides a routing device, which routes uplink data.

[0233] FIG. 25 is a schematic diagram of an example of a routing device according to an embodiment of the present invention. The device may be, for example, an IAB node in an IAB system, or a component or component configured in an IAB node. The IAB node functions as a parent node. Here, the implementation principle of the routing device according to the embodiment of the present invention is the same as that of the IAB node in FIG. 17 in Embodiment 2, and duplicate descriptions of the same content are omitted.

[0234] As shown in FIG. 25, a routing device 2500 according to an embodiment of the present invention includes the following parts.

[0235] When it is detected that an RLF has occurred on one or more ingress links, the transmission unit 2501 transmits RLF indication information to the child node. The RLF indication information includes an identifier of a routing in which the egress link corresponding to the address of the next hop in the routing configuration of the routing table of the IAB node is the link where the RLF has occurred, so that the child node routes the uplink data based on the RLF indication information.

[0236] In some embodiments, if an IAB node has a donor-CU uplink routing substitution table configured and it is determined that the link where the RLF occurred is an ingress link corresponding to a second donor-CU, the transmitter 2501 determines, based on the second routing table (routing table for the second donor-CU topology domain), that the egress link corresponding to the next hop address is the third routing identifier of the ingress link corresponding to the second donor-CU, and based on the donor-CU uplink routing substitution table, it determines a fourth routing identifier that needs to be replaced by the third routing identifier, and transmits RLF instruction information to the child node. The RLF instruction information includes the fourth routing identifier, where the third routing identifier belongs to the second donor-CU topology domain and the fourth routing identifier belongs to the first donor-CU topology domain.

[0237] In some embodiments, if it is determined that the IAB node does not have a donor-CU uplink routing substitution table configured, or if the link where the RLF occurred is an ingress link corresponding to the first donor-CU, the transmitter 2501 determines, based on the first routing table (routing table for the first donor-CU topology domain), that the egress link corresponding to the next hop address is the third routing identifier of the ingress link corresponding to the first donor-CU, and transmits RLF instruction information to the child node. The RLF instruction information includes the third routing identifier. Here, the IAB node and the first donor-CU have established an F1 connection, and the third routing identifier belongs to the first donor-CU topology domain.

[0238] Figure 26 is a schematic diagram of another example of a routing device according to an embodiment of the present invention. The device may be, for example, an IAB node in an IAB system, or a component configured in an IAB node. The IAB node functions as a child node. Here, the implementation principle of the routing device according to an embodiment of the present invention is the same as the child node embodiment in Figure 19 in Embodiment 2, and redundant explanations of similar content are omitted.

[0239] As shown in Figure 26, the routing device 2600 according to an embodiment of the present invention includes the following parts.

[0240] The receiving unit 2601 receives RLF instruction information from the IAB node. This RLF instruction information includes a routing identifier that indicates the link corresponding to the next hop address is the link where the RLF occurred.

[0241] The processing unit 2602 routes the uplink data based on the RLF instruction information.

[0242] In some embodiments, the routing of uplink data by the processing unit 2602 based on RLF instruction information includes the processing unit 2602 determining whether routing is available based on the RLF instruction information, and routing the uplink data based on whether routing is available.

[0243] In some embodiments, the determination by the processing unit 2602 of whether routing is available based on RLF instruction information includes the determination by the processing unit 2602 of whether the link corresponding to the IAB node is not available for routing based on RLF instruction information.

[0244] For example, if the link corresponding to the IAB node is an ingress link corresponding to the first donor-CU, the processing unit 2602 determines that the link corresponding to the IAB node is not available for routing in the first routing table.

[0245] Furthermore, for example, if the link corresponding to the IAB node is an ingress link corresponding to the second donor-CU, the processing unit 2602 determines that the link corresponding to the IAB node is not available for routing in the second routing table.

[0246] In some embodiments, if it is determined that the link corresponding to the IAB node is not available for the routing, the processing unit 2602 may change the availability of the routing in the routing table to not available (NO).

[0247] In some embodiments, routing uplink data based on whether routing is available includes selecting an egress link for the uplink data based on whether routing is available.

[0248] In some embodiments, if a donor-CU uplink routing substitution table is configured in a child node, and it is determined that the first routing identifier in the BAP header of the uplink data belongs to the substituted routing identifier in the donor-CU uplink routing substitution table, the processing unit 2602 replaces the first routing identifier in the BAP header of the uplink data with the corresponding second routing identifier based on the donor-CU uplink routing substitution table. If the child node's second routing table has a routing configuration that satisfies the first condition, the processing unit 2602 sets the egress link corresponding to the next-hop address in the routing configuration as the first egress link in the uplink data. The first condition means that the routing identifier in the routing configuration matches the second routing identifier, and the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration. Here, the first routing identifier belongs to the first donor-CU topology domain, and the second routing identifier belongs to the second donor-CU topology domain.

[0249] In the above embodiment, if the second routing table of the child node does not contain a routing configuration that satisfies the first condition, the processing unit 2602 determines whether the second routing table of the child node contains a routing configuration that satisfies the third condition. If the second routing table of the child node contains a routing configuration that satisfies the third condition, the processing unit 2602 sets the egress link corresponding to the next-hop address in the routing configuration as the egress link for the data packet of the uplink data. The third condition means that the destination BAP address of the routing identifier in the routing configuration matches the destination BAP address of the second routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0250] In the above embodiment, if the second routing table of the child node does not contain a routing configuration that satisfies the third condition, the processing unit 2602 determines whether the child node has a second donor-CU routing substitution table configured. If the child node has a second donor-CU routing substitution table configured, and the second routing identifier belongs to a substituted routing identifier in the second donor-CU routing substitution table and is substituted with the fifth routing identifier, the processing unit 2602 determines whether the child node's second routing table contains a routing configuration that satisfies the fifth condition. If the child node's second routing table contains a routing configuration that satisfies the fifth condition, the processing unit 2602 changes the second routing identifier in the header of the uplink data packet to the corresponding fifth routing identifier based on the second donor-DU routing substitution table, and sets the egress link corresponding to the next-hop address in the routing configuration as the egress link of the uplink data packet. The fifth condition includes that the routing identifier in the routing configuration matches the fifth routing identifier, or that the destination address in the routing configuration matches the destination address of the fifth routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0251] In the above embodiment, if the second routing table of the child node does not contain a routing configuration that satisfies the fifth condition, the processing unit 2602 determines whether the child node has a first routing table configured. If the child node has a first routing table configured, the processing unit 2602 determines whether the first routing table of the child node contains a routing configuration that satisfies the seventh condition. If the first routing table of the child node contains a routing configuration that satisfies the seventh condition, the processing unit 2602 changes the first routing identifier in the header of the uplink data packet to the seventh routing identifier, and sets the egress link corresponding to the next-hop address in the routing configuration as the egress link for the uplink data packet. The seventh condition includes that the routing identifier in the routing configuration matches the seventh routing identifier, or that the destination address in the routing configuration matches the destination address of the seventh routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0252] In some embodiments, if it is determined that a donor-CU uplink routing substitution table is not configured in a child node, or if the first routing identifier in the uplink data header does not belong to the substituted routing identifier in the donor-CU uplink routing substitution table, and the child node's first routing table has a routing configuration that satisfies a second condition, the processing unit 2602 sets the egress link corresponding to the next hop address in the routing configuration as the first egress link in the downlink data. The second condition means that the routing identifier in the routing configuration matches the first routing identifier, and the egress link corresponding to the next hop address in the routing configuration is available for routing in the routing configuration. Here, the first routing identifier belongs to the first donor-CU topology domain.

[0253] In the above embodiment, if the child node's first routing table does not contain a routing configuration that satisfies the second condition, the processing unit 2602 determines whether the child node's first routing table contains a routing configuration that satisfies the fourth condition. If the child node's first routing table contains a routing configuration that satisfies the fourth condition, the processing unit 2602 sets the egress link corresponding to the next-hop address in the routing configuration as the egress link for the uplink data packet. The fourth condition means that the destination BAP address of the routing identifier in the routing configuration matches the destination BAP address of the first routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0254] In the above embodiment, if the child node's first routing table does not contain a routing configuration that satisfies the fourth condition, the processing unit 2602 determines whether the child node has a first donor-CU routing substitution table configured. If the child node has a first donor-CU routing substitution table configured, and the first routing identifier belongs to a substituted routing identifier in the first donor-CU routing substitution table and is substituted with the sixth routing identifier, the processing unit 2602 determines whether the child node's first routing table contains a routing configuration that satisfies the sixth condition. If the child node's first routing table contains a routing configuration that satisfies the sixth condition, the processing unit 2602 uses the egress link corresponding to the next-hop address in the routing configuration as the egress link for the uplink data packet, based on the first donor-DU routing substitution table. The sixth condition includes that the routing identifier in the routing configuration matches the sixth routing identifier, or that the destination address in the routing configuration matches the destination address of the sixth routing identifier, and that the egress link corresponding to the next-hop address in the routing configuration is available for routing in the routing configuration.

[0255] In the above embodiment, when there is no routing configuration in the first routing table of the child node that satisfies the sixth condition, the processing unit 2602 determines whether a second routing table is configured in the child node. When a second routing table is configured in the child node, it is determined whether there is a routing configuration that satisfies the eighth condition in the second routing table of the child node. When there is a routing configuration that satisfies the eighth condition in the second routing table of the child node, the processing unit 2602 changes the first routing identifier in the header of the data packet of the uplink data to the eighth routing identifier, and sets the egress link corresponding to the address of the next hop in the routing configuration as the egress link of the data packet of the uplink data. The eighth condition includes that the routing identifier in the routing configuration matches the eighth routing identifier, or the destination address in the routing configuration matches the destination address of the eighth routing identifier, and the egress link corresponding to the address of the next hop in the routing configuration is available for the routing in the routing configuration.

[0256] In an embodiment of the present invention, as shown in FIG. 26, the routing device 2600 further includes the following units.

[0257] The transmitting unit 2603 transfers the RLF indication information to the child node of the child node.

[0258] In some embodiments, if a child node is configured with a donor-CU uplink routing substitution table, and RLF instruction information is received from an ingress link corresponding to a second donor-CU, and the RLF instruction information includes a third routing identifier, the transmitter 2603 determines a fourth routing identifier that needs to be substituted for the third routing identifier based on the donor-CU uplink routing substitution table, and transmits the RLF instruction information to its child node, the RLF instruction information including the fourth routing identifier. Here, the third routing identifier belongs to the second donor-CU topology domain, and the fourth routing identifier belongs to the first donor-CU topology domain.

[0259] In some embodiments, if it is determined that a donor-CU uplink routing substitution table is not configured for a child node, or if the RLF instruction information is received from an ingress link corresponding to a first donor-CU and the RLF instruction information includes a third routing identifier, the transmitter 2603 transmits the RLF instruction information to its child node, and the RLF instruction information includes a third routing identifier. Here, the third routing identifier belongs to the first donor-CU topology domain.

[0260] Although the above description only concerns components or modules related to the present invention, the present invention is not limited thereto. The routing devices 2500 and 2600 according to embodiments of the present invention may further include other components or modules. For specific details of these components or modules, refer to related technologies.

[0261] Furthermore, for the sake of clarity, Figures 25 and 26 merely illustrate the connection relationships or signal directions between various components or modules; however, it will be apparent to those skilled in the art that various related techniques, such as bus connections, can be used. The above-mentioned components or modules may be implemented by hardware devices such as processors, memory, transmitters, and receivers, and the present invention is not limited thereto.

[0262] According to embodiments of the present invention, it is possible to avoid congested routing and the selection of BH RLC channels, thereby mitigating and resolving the problems of congestion and loss of downlink data.

[0263] <Example 5> An embodiment of the present invention provides a communication system. Figure 27 is a schematic diagram of the communication system 2700. As shown in Figure 27, the communication system 2700 includes Donor devices 2701 and 2702, IAB nodes 2703 and 2704, and a terminal device 2705. Here, Donor devices 2701 and 2702 are also a type of IAB node. IAB node 2703 may also establish a dual connection with two Donor devices 2701 and 2702. Donor devices 2701 and 2702 may function as parent nodes of IAB node 2703, and IAB node 2703 may function as parent node of IAB node 2704. Accordingly, IAB node 2703 may function as a child node of Donor devices 2701 and 2702, and IAB node 2704 may function as a child node of IAB node 2703. The parent IAB nodes (e.g., Donor devices 2701 and 2702, and IAB node 2703) may implement the functions of the IAB nodes in Example 1 and Example 2, and the child IAB nodes (e.g., IAB nodes 2703 and 2704) may implement the functions of the child nodes in Example 1 and Example 2.

[0264] For simplicity, Figure 27 illustrates only two Donor devices, two IAB nodes, and one terminal device as an example; however, embodiments of the present invention are not limited to this. The network configuration of the Donor devices, IAB nodes, and terminal devices may be described by referring to related technologies, and such a description is omitted here.

[0265] In some embodiments, Donor devices 2701 and 2702, and IAB node 2703 are configured as parent nodes to perform the method performed by the IAB node in Embodiment 1 or Embodiment 2, i.e., the method of Figure 12 or Figure 17, and may include the apparatus of Figure 22 or Figure 25.

[0266] In some embodiments, IAB nodes 2703 and 2704 are configured as child nodes to perform the methods carried out by the child nodes in Embodiment 1 or Embodiment 2, i.e., the methods shown in Figures 14A, 14B, or 19, and may include the apparatus shown in Figures 23, 24, or 26.

[0267] In some embodiments, the parent node (IAB node) and the child node (IAB device) may be described by referring to Embodiments 1 to 4, and their description is omitted here.

[0268] Several embodiments further provide IAB nodes.

[0269] Figure 28 is a schematic diagram of an example of an IAB node according to an embodiment of the present invention. As shown in Figure 28, the IAB node 2800 may include a processor 2801 (e.g., a central processing unit (CPU)) and a memory 2802, the memory 2802 being connected to the processor 2801. The memory 2802 may store various types of data, and may also store information processing programs and execute these programs under the control of the processor 2801.

[0270] In some embodiments, the processor 2801 may be configured to execute a program to implement the method performed by the IAB node or child node in Example 1 or Example 2.

[0271] Furthermore, as shown in Figure 28, the IAB node 2800 may further include a transceiver 2803 and an antenna 2804, etc. The functions of the above components are similar to those of the prior art, and their explanation is omitted here. Note that the IAB node 2800 does not need to include all the units shown in Figure 28. The IAB node 2800 may also include units not shown in Figure 28, and prior art may be referenced.

[0272] In embodiments of the present invention, the present invention further provides a computer-readable program that, when executed on an IAB node, causes the computer to execute on the IAB node the method executed by the IAB node or child node in Embodiment 1 or Embodiment 2.

[0273] Embodiments of the present invention further provide a storage medium in which a computer-readable program is stored, and which, when executing the program, causes the computer to execute a method performed by the IAB node or child node in Embodiment 1 or Embodiment 2 on the IAB node.

[0274] The above-described apparatus and method of the present invention may be implemented by hardware, or by combining hardware and software. The present invention relates to a computer-readable program, and when the program is executed by a logic unit, the logic unit may implement the above-described apparatus or configuration requirements, or the logic unit may implement the above-described methods or steps. The present invention relates to a storage medium for storing the above-described program, such as a hard disk, magnetic disk, optical disk, DVD, flash memory, etc.

[0275] Each processing method in each apparatus described with reference to embodiments of the present invention may be implemented using hardware, software modules executed by a processor, or a combination of both. For example, one or more functional block diagrams shown in the drawings, or one or more combinations of functional block diagrams, may correspond to each software module in a computer program flow, or to each hardware module. These software modules may correspond to each step shown in the drawings. These hardware modules may be implemented by hardwareizing these software modules, for example, using a field-programmable gate array (FPGA).

[0276] The software module may reside 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 can read information from or write information to the storage medium, or the storage medium may be a component of the processor. The processor and the storage medium may reside in an ASIC. The software module may be stored in the memory of the mobile terminal or on a memory card inserted into the mobile terminal. For example, if the device (e.g., a mobile terminal) uses a relatively large capacity MEGA-SIM card or a high-capacity flash memory device, the software module may be stored on the MEGA-SIM card or high-capacity flash memory device.

[0277] One or more functional blocks and / or one or more combinations of functional blocks in the functional block diagrams shown in the drawings may be implemented by 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 unit, a discrete hardware component, or any suitable combination thereof for performing the functions described herein. One or more functional blocks and / or one or more combinations of functional blocks in the functional block diagrams shown in the drawings may be implemented, for example, by a combination of computing equipment, such as a combination of a DSP and a microprocessor, a combination of multiple microprocessors, one or more microprocessors combined with DSP communication, or any other configuration.

[0278] 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 can be made to the present invention as long as they do not deviate from the spirit and principles of the present invention, and these modifications and changes are also within the scope of the present invention.

[0279] With regard to embodiments including the above-described examples, the following further notes are disclosed. (Note 1) A routing method configured on an IAB node in an IAB system, A step in which an IAB node receives flow control instruction information for a BH RLC channel and / or routing from a child node, wherein the flow control instruction information includes the available buffer size for the BH RLC channel and the identifier of the BH RLC channel, and / or the available buffer size for the routing and the identifier of the routing, A method comprising the step of routing downlink data based on the available buffer size of the IAB node. (Note 2) The IAB node routing downlink data based on the available buffer size means that The IAB node determines whether the BH RLC channel and / or routing are congested and available based on the available buffer size. The method according to Appendix 1, wherein the IAB node routes downlink data based on whether the BH RLC channel and / or routing is available. (Note 3) The method according to Appendix 2, wherein if the available buffer size for the routing is smaller than a first buffer threshold, it is determined that the routing is congested and the link corresponding to the child node is not available for the routing; or, if the available buffer size for the BH RLC channel is smaller than a second buffer threshold, it is determined that the BH RLC channel is congested and the BH RLC channel for the link corresponding to the child node is not available. (Note 4) The IAB node routing downlink data based on whether the routing is available is: The method according to Appendix 2, wherein the IAB node selects an egress link for the downlink data based on whether the routing is available. (Note 5) The IAB node selects an egress link for the downlink data based on whether the routing is available. If a donor-CU downlink routing substitution table is configured on the IAB node, and it is determined that the downlink data originates from an ingress link corresponding to a second donor-CU, then, based on the donor-CU downlink routing substitution table, the first routing identifier in the BAP header of the downlink data is replaced with the corresponding second routing identifier, wherein the first routing identifier belongs to the second donor-CU topology domain, and the second routing identifier belongs to the first donor-CU topology domain. If the routing table of the IAB node contains a routing configuration that satisfies the second condition, the egress link corresponding to the next hop address in the routing configuration is set as the first egress link of the downlink data, The method according to Appendix 4, wherein the second condition means that the routing identifier in the routing configuration matches the second routing identifier, and the egress link corresponding to the next hop address in the routing configuration is available for routing in the routing configuration. (Note 6) After replacing the first routing identifier in the BAP header of the downlink data with the corresponding second routing identifier, The method according to Appendix 5, further comprising the step of passing the downlink data to the upper layer of the IAB node if the destination BAP address of the second routing identifier is a BAP address configured for the IAB node by the first donor-CU. (Note 7) If a donor-CU downlink routing substitution table is configured on the aforementioned IAB node, and it is determined that the downlink data originates from the ingress link corresponding to the second donor-CU, The method according to Appendix 4, further comprising the step of passing the downlink data to the upper layer of the IAB node when the destination BAP address of the first routing identifier in the BAP header of the downlink data is a BAP address configured for the IAB node by the second donor-CU. (Note 8) Selecting an egress link for the uplink data based on whether the aforementioned routing is available is, If it is determined that the IAB node does not have a donor-CU downlink routing substitution table configured, or if the IAB node has a donor-CU downlink routing substitution table configured and it is determined that the downlink data originates from an ingress link corresponding to a first donor-CU, and the first routing identifier in the header of the downlink data belongs to the first donor-CU topology domain, When the routing table of the IAB node contains a routing configuration that satisfies the first condition, the egress link corresponding to the next hop address in the routing configuration is set as the first egress link of the downlink data. The method according to Appendix 4, wherein the first condition means that the routing identifier in the routing configuration matches the first routing identifier, and the egress link corresponding to the next hop address in the routing configuration is available for routing in the routing configuration. (Note 9) If it is determined that the IAB node does not have a donor-CU downlink routing substitution table configured, or if the IAB node has a donor-CU downlink routing substitution table configured and it is determined that the downlink data is from the ingress link corresponding to the first donor-CU, The method according to Appendix 4, further comprising the step of passing the downlink data to the upper layer of the IAB node when the destination BAP address of the first routing identifier in the BAP header of the downlink data is a BAP address configured for the IAB node by the first donor-CU. (Note 10) If the routing table of the IAB node does not contain a routing configuration that satisfies the first condition, it is determined whether or not the routing table of the IAB node contains a routing configuration that satisfies the third condition. If the routing table of the IAB node contains a routing configuration that satisfies the third condition, the egress link corresponding to the next hop address in the routing configuration shall be set as the first egress link of the downlink data. The method according to Appendix 8, wherein the third condition means that the destination BAP address of the routing identifier in the routing configuration matches the destination BAP address of the first routing identifier, and the egress link corresponding to the next hop address in the routing configuration is available for routing in the routing configuration. (Note 11) The IAB node routing downlink data based on whether the routing is available is: The method according to Appendix 4, wherein the IAB node selects an egress BH RLC channel for the downlink data based on whether the BH RLC channel is available. (Note 12) The aforementioned IAB node is a donor node of the IAB system, Selecting an egress BH RLC channel for the downlink data based on whether the BH RLC channel is available is: If the RLC channel mapping table of the IAB node contains a BH RLC channel configuration that satisfies the fourth condition, the egress BH RLC channel in the BH RLC channel configuration is selected as the egress BH RLC channel for the downlink data. The method according to Appendix 11, wherein the fourth condition means that the destination IP address and DSCP in the BH RLC channel configuration match the destination IP address and DSCP in the IP header of the downlink data, and the egress link corresponding to the next hop address in the BH RLC channel configuration matches the first egress link of the downlink data, and the egress BH RLC channel in the BH RLC channel configuration is available. (Note 13) If there is no BH RLC channel configuration that satisfies the fourth condition in the RLC channel mapping table of the IAB node, the available egress BH RLC channel of the first egress link is selected as the egress BH RLC channel for the downlink data. The method according to Appendix 12, wherein if there is no BH RLC channel available on the first egress link, a second egress link available for the downlink data is selected. (Note 14) If there is no BH RLC channel configuration that satisfies the fourth condition in the RLC channel mapping table of the IAB node, select a second egress link available for the downlink data. The method according to Appendix 12, wherein if there is no available second egress link, an available egress BH RLC channel in the first egress link is selected as the egress BH RLC channel for the downlink data. (Note 15) The aforementioned IAB node is an intermediate node of the IAB system, Selecting an egress BH RLC channel for the downlink data based on whether the BH RLC channel is available is: If the RLC channel mapping table of the IAB node contains a BH RLC channel configuration that satisfies the fifth condition, the egress BH RLC channel in the BH RLC channel configuration is selected as the egress BH RLC channel for the downlink data. The method according to Appendix 11, wherein the fifth condition means that the address of the preceding hop and the ingress RLC channel ID in the BH RLC channel configuration match the downlink data, and the egress link corresponding to the address of the next hop in the BH RLC channel configuration matches the first egress link in the downlink data, and the egress BH RLC channel in the BH RLC channel configuration is available. (Note 16) If there is no BH RLC channel configuration that satisfies the fifth condition in the RLC channel mapping table of the IAB node, the available egress BH RLC channel of the first egress link is selected as the egress BH RLC channel for the downlink data. The method according to Appendix 15, wherein if there is no BH RLC channel available on the first egress link, a second egress link available for the downlink data is selected. (Note 17) If there is no BH RLC channel configuration that satisfies the fifth condition in the RLC channel mapping table of the IAB node, select a second egress link available for the downlink data. The method according to Appendix 15, wherein if there is no available second egress link, an available egress BH RLC channel of the first egress link is selected as the egress BH RLC channel for the downlink data. (Note 18) The method according to Appendix 1, further comprising the step of the IAB node transferring the flow control instruction information to the parent node of the IAB node. (Note 19) If the IAB node has a donor-CU downlink routing substitution table configured, and it is determined that the third routing identifier included in the flow control instruction information belongs to a substitution routing identifier in the donor-CU downlink routing substitution table, the IAB node changes the third routing identifier in the flow control instruction information to the corresponding fourth routing identifier based on the donor-CU downlink routing substitution table, and transmits the flow control instruction information to the egress link corresponding to the second donor-CU. The method according to Appendix 18, wherein the third routing identifier belongs to the first donor-CU topology domain, and the fourth routing identifier belongs to the second donor-CU topology domain. (Note 20) If it is determined that the IAB node does not have a donor-CU downlink routing substitution table configured, or if it is determined that the third routing identifier included in the flow control instruction information does not belong to the substitution routing identifier in the donor-CU downlink routing substitution table, the IAB node transmits the flow control instruction information including the third routing identifier to the egress link corresponding to the first donor-CU. The third routing identifier is the method described in Appendix 18, belonging to the first donor-CU topology domain. (Note 21) A routing method configured for a child node of an IAB node in an IAB system, A method comprising the step of sending flow control instruction information based on a BH RLC channel to an IAB node when the BH RLC channel buffer exceeds a third buffer threshold, wherein the flow control instruction information includes the available buffer size for the BH RLC channel and an identifier for the BH RLC channel, so that the IAB node routes downlink data based on the available buffer size. (Note 22) A routing method configured for a child node of an IAB node in an IAB system, A method comprising the step of sending routing-based flow control instruction information to the IAB node when the buffer for the fifth routing exceeds a fourth buffer threshold, wherein the flow control instruction information includes the available buffer size and the fifth routing identifier for the fifth routing, so that the IAB node routes downlink data based on the available buffer size. (Note 23) If a donor-CU downlink routing substitution table is configured in the child node, and it is determined that the fifth routing identifier belongs to a substitution routing identifier in the donor-CU downlink routing substitution table, the child node includes a sixth routing identifier corresponding to the fifth routing identifier in the donor-CU downlink routing substitution table in the flow control instruction information and transmits it to the egress link corresponding to the second donor-CU. The method as described in Appendix 22, wherein the fifth routing identifier belongs to the first donor-CU topology domain, and the sixth routing identifier belongs to the second donor-CU topology domain. (Note 24) If it is determined that the child node does not have a donor-CU downlink routing substitution table configured, or if it is determined that the fifth routing identifier included in the flow control instruction information does not belong to the substitution routing identifiers in the donor-CU downlink routing substitution table, the child node transmits the flow control instruction information including the fifth routing identifier to the egress link corresponding to the first donor-CU. The fifth routing identifier is the method described in Appendix 22, belonging to the first donor-CU topology domain. (Note 25) A routing method configured on an IAB node in an IAB system, A method comprising the step of sending RLF instruction information to a child node when an IAB node detects that an RLF has occurred on one or more ingress links, wherein the RLF instruction information includes a routing identifier in the routing configuration of the IAB node's routing table, where the egress link corresponding to the next hop address is the link on which the RLF occurred, so that the child node routes uplink data based on the RLF instruction information. (Note 26) Sending RLF instruction information to the aforementioned child node means If the IAB node has a donor-CU uplink routing substitution table configured, and the link where the RLF occurred is determined to be an ingress link corresponding to a second donor-CU, then the IAB node determines, based on the second routing table, that the egress link corresponding to the next hop address is the third routing identifier of the ingress link corresponding to the second donor-CU, wherein the second routing table is a routing table for the second donor-CU topology domain. The IAB node determines, based on the donor-CU uplink routing substitution table, a fourth routing identifier that needs to be replaced by a third routing identifier, The IAB node transmits RLF instruction information to a child node, wherein the RLF instruction information includes the fourth routing identifier, The method described in Appendix 25, wherein the third routing identifier belongs to the second donor-CU topology domain, and the fourth routing identifier belongs to the first donor-CU topology domain. (Note 27) Sending RLF instruction information to the aforementioned child node means If it is determined that the IAB node does not have a donor-CU uplink routing substitution table configured, or if the link where the RLF occurred is an ingress link corresponding to a first donor-CU, the IAB node determines, based on a first routing table, that the egress link corresponding to the next hop address is the third routing identifier of the ingress link corresponding to the first donor-CU, wherein the first routing table is a routing table for the first donor-CU topology domain. The IAB node transmits RLF instruction information to a child node, wherein the RLF instruction information includes the third routing identifier. The method described in Appendix 25, wherein an F1 connection is established between the IAB node and the first donor-CU, and the third routing identifier belongs to the first donor-CU topology domain. (Note 28) A routing method configured for a child node of an IAB node in an IAB system, A step in which a child node receives RLF instruction information from an IAB node, wherein the RLF instruction information includes a routing identifier in which the link corresponding to the address of the next hop is the link where the RLF occurred. A method comprising the step of the child node routing uplink data based on the RLF instruction information. (Note 29) The child node routing uplink data based on the RLF instruction information means that The child node determines whether the routing is available based on the RLF instruction information, The method according to Appendix 28, comprising routing uplink data on whether the child node is available for routing. (Note 30) The child node determines whether the routing is available based on the RLF instruction information, The method according to Appendix 29, wherein the child node determines, based on the RLF instruction information, that the link corresponding to the IAB node is not available for routing. (Note 31) The method according to Appendix 30, wherein if the link corresponding to the IAB node is an ingress link corresponding to a first donor-CU, the child node determines that the link corresponding to the IAB node is not available for the routing in the first routing table, and the first routing table is a routing table for the first donor-CU topology domain. (Note 32) The method according to Appendix 30, wherein if the link corresponding to the IAB node is an ingress link corresponding to a second donor-CU, the child node determines that the link corresponding to the IAB node is not available for the routing in the second routing table, the second routing table being a routing table for the second donor-CU topology domain. (Note 33) The method according to Appendix 30, further comprising the step of changing the availability of the routing in the routing table of the child node to unavailable (NO). (Note 34) The child node routes uplink data based on whether the routing is available. The method according to Appendix 30, comprising selecting an egress link for the uplink data based on whether the aforementioned routing is available. (Note 35) Selecting an egress link for the uplink data based on whether the aforementioned routing is available is, If a donor-CU uplink routing substitution table is configured in the child node, and it is determined that the first routing identifier in the BAP header of the uplink data belongs to the substituted routing identifier in the donor-CU uplink routing substitution table, the child node shall substitute the first routing identifier in the BAP header of the uplink data with the corresponding second routing identifier based on the donor-CU uplink routing substitution table. If the second routing table of the child node contains a routing configuration that satisfies the first condition, the child node sets the egress link corresponding to the next hop address in the routing configuration as the first egress link of the uplink data, The first condition means that the routing identifier in the routing configuration matches the second routing identifier, and that the egress link corresponding to the next hop address in the routing configuration is available for routing in the routing configuration. The method according to Appendix 34, wherein the first routing identifier belongs to a first donor-CU topology domain, and the second routing identifier belongs to a second donor-CU topology domain. (Note 36) If the second routing table of the child node does not contain a routing configuration that satisfies the first condition, it is determined whether or not the second routing table of the child node contains a routing configuration that satisfies the third condition. If the second routing table of the child node contains a routing configuration that satisfies the third condition, the egress link corresponding to the next hop address in the routing configuration shall be set as the egress link for the data packet of the uplink data. The method according to Appendix 35, wherein the third condition means that the destination BAP address of the routing identifier in the routing configuration matches the destination BAP address of the second routing identifier, and the egress link corresponding to the address of the next hop in the routing configuration is available for routing in the routing configuration. (Note 37) If the second routing table of the child node does not contain a routing configuration that satisfies the third condition, it is determined whether or not a second donor-CU routing substitution table is configured in the child node. If the child node has the second donor-CU routing substitution table configured, and the second routing identifier belongs to the substituted routing identifier in the second donor-CU routing substitution table and is substituted with the fifth routing identifier, then it is determined whether the second routing table of the child node has a routing configuration that satisfies the fifth condition. If the second routing table of the child node contains a routing configuration that satisfies the fifth condition, the child node, based on the second donor-DU routing substitution table, changes the second routing identifier in the header of the uplink data packet to the corresponding fifth routing identifier, and sets the egress link corresponding to the next-hop address in the routing configuration as the egress link of the uplink data packet. The method according to Appendix 36, wherein the fifth condition includes that the routing identifier in the routing configuration matches the fifth routing identifier, or that the destination address in the routing configuration matches the destination address of the fifth routing identifier, and that the egress link corresponding to the next hop address in the routing configuration is available for routing in the routing configuration. (Note 37a) If the second routing table of the child node does not contain a routing configuration that satisfies the fifth condition, it is determined whether or not the first routing table is configured in the child node. If a first routing table is configured in the child node, determine whether the first routing table of the child node has a routing configuration that satisfies the seventh condition. If the first routing table of the child node contains a routing configuration that satisfies the seventh condition, the child node changes the first routing identifier in the header of the uplink data packet to the seventh routing identifier, and sets the egress link corresponding to the next hop address in the routing configuration as the egress link of the uplink data packet. The method according to Appendix 37, wherein the seventh condition includes that the routing identifier in the routing configuration matches the seventh routing identifier, or that the destination address in the routing configuration matches the destination address of the seventh routing identifier, and that the egress link corresponding to the next hop address in the routing configuration is available for routing in the routing configuration. (Note 38) Selecting an egress link for the uplink data based on whether the aforementioned routing is available is, If it is determined that the donor-CU inter-uplink routing substitution table is not configured for the child node, or if the first routing identifier in the uplink data header does not belong to the substituted routing identifier in the donor-CU inter-uplink routing substitution table, When the first routing table of the child node contains a routing configuration that satisfies the second condition, the egress link corresponding to the address of the next hop in the routing configuration is set as the first egress link of the downlink data. The second condition means that the routing identifier in the routing configuration matches the first routing identifier, and that the egress link corresponding to the next hop address in the routing configuration is available for routing in the routing configuration. The first routing identifier is the method described in Appendix 34, belonging to the first donor-CU topology domain. (Note 39) If the first routing table of the child node does not contain a routing configuration that satisfies the second condition, it is determined whether or not the first routing table of the child node contains a routing configuration that satisfies the fourth condition. If the first routing table of the child node contains a routing configuration that satisfies the fourth condition, the egress link corresponding to the next hop address in the routing configuration shall be set as the egress link for the data packet of the uplink data. The method according to Appendix 38, wherein the fourth condition means that the destination BAP address of the routing identifier in the routing configuration matches the destination BAP address of the first routing identifier, and the egress link corresponding to the address of the next hop in the routing configuration is available for routing in the routing configuration. (Note 40) If the first routing table of the child node does not contain a routing configuration that satisfies the fourth condition, it is determined whether or not the first donor-CU routing substitution table is configured in the child node. If the child node has the first donor-CU routing substitution table configured, and the first routing identifier belongs to the substituted routing identifier in the first donor-CU routing substitution table and is substituted with the sixth routing identifier, then it is determined whether the child node's first routing table has a routing configuration that satisfies the sixth condition. If the first routing table of the child node contains a routing configuration that satisfies the sixth condition, the child node, based on the first donor-DU routing substitution table, sets the egress link corresponding to the next-hop address in the routing configuration as the egress link for the data packet of the uplink data. The method according to Appendix 39, wherein the sixth condition includes that the routing identifier in the routing configuration matches the sixth routing identifier, or that the destination address in the routing configuration matches the destination address of the sixth routing identifier, and that the egress link corresponding to the next hop address in the routing configuration is available for routing in the routing configuration. (Note 40a) If the first routing table of the child node does not contain a routing configuration that satisfies the sixth condition, it is determined whether or not a second routing table is configured in the child node. If a second routing table is configured in the child node, it is determined whether the second routing table of the child node contains a routing configuration that satisfies the eighth condition. If the second routing table of the child node contains a routing configuration that satisfies the eighth condition, the child node changes the first routing identifier in the header of the uplink data packet to the eighth routing identifier, and sets the egress link corresponding to the next hop address in the routing configuration as the egress link of the uplink data packet. The method according to Appendix 40, wherein the eighth condition includes that the routing identifier in the routing configuration matches the eighth routing identifier, or that the destination address in the routing configuration matches the destination address of the eighth routing identifier, and that the egress link corresponding to the next hop address in the routing configuration is available for routing in the routing configuration. (Note 41) The method according to any one of the appendices 28 to 40, further comprising the step of the child node transferring the RLF instruction information to the child node's child node. (Note 42) If the child node is configured with an uplink routing substitution table between donor-CUs, and the RLF instruction information is received from the ingress link corresponding to the second donor-CU, and the RLF instruction information includes a third routing identifier, The child node determines, based on the donor-CU uplink routing substitution table, a fourth routing identifier that needs to be substituted for the third routing identifier. The child node transmits RLF instruction information to its own child node, and the RLF instruction information includes the fourth routing identifier. The method according to Appendix 41, wherein the third routing identifier belongs to the second donor-CU topology domain, and the fourth routing identifier belongs to the first donor-CU topology domain. (Note 43) If it is determined that the donor-CU inter-uplink routing substitution table is not configured in the child node, or if the RLF instruction information was received from the ingress link corresponding to the first donor-CU and the RLF instruction information includes a third routing identifier, The child node transmits RLF instruction information to its own child node, and the RLF instruction information includes the third routing identifier. The third routing identifier is the method described in Appendix 41, belonging to the first donor-CU topology domain. (Note 44) An IAB node comprising a memory in which a computer program is stored and a processor, wherein the processor is configured to execute the computer program to realize the method described in any of the appendices 1 to 43. (Note 45) A communication system comprising a Donor device, IAB nodes, and terminal devices, wherein the parent node among the IAB nodes is configured to perform the method described in any of Appendices 1 to 27, and / or the child node among the IAB nodes is configured to perform the method described in any of Appendices 28 to 43.

Claims

1. A routing device configured on an IAB node, A receiving unit that receives downlink data from an ingress link corresponding to a second donor-CU, wherein the second donor-CU is a donor-CU that has not established an F1 association with the IAB node, If an egress link is available, a processing unit that selects the egress link for the downlink data includes: If the IAB node is configured with a donor-CU header rewriting configuration and it is determined that the downlink data is from an ingress link corresponding to the second donor-CU, the processing unit replaces the first routing identifier in the BAP header of the downlink data with the corresponding second routing identifier based on the donor-CU header rewriting configuration, wherein the first routing identifier belongs to the second donor-CU topology domain, the second routing identifier belongs to the first donor-CU topology domain, and the first donor-CU is a donor-CU that has established an F1 association with the IAB node. If the first routing table of the IAB node contains a routing entry that satisfies the second condition, the processing unit sets the egress link corresponding to the next hop address in the routing entry as the first egress link of the downlink data. The first routing table is for the first donor-CU topology domain, and the second condition means that the routing identifier in the routing entry matches the second routing identifier, and that an egress link corresponding to the next hop address in the routing entry is available. If the destination BAP address of the first routing identifier in the BAP header of the downlink data is a BAP address configured for the IAB node by the second donor-CU, the IAB node is a device that passes the downlink data to a higher layer of the IAB node.

2. The apparatus according to claim 1, further comprising a transmission unit for transferring flow control instruction information to the parent node of the IAB node.

3. If a donor-CU downlink routing substitution table is configured in the IAB node, and it is determined that the third routing identifier included in the flow control instruction information belongs to a substitution routing identifier in the donor-CU downlink routing substitution table, the transmission unit changes the third routing identifier in the flow control instruction information to the corresponding fourth routing identifier based on the donor-CU downlink routing substitution table, and transmits the flow control instruction information to the egress link corresponding to the second donor-CU. The apparatus according to claim 2, wherein the third routing identifier belongs to a first donor-CU topology domain, and the fourth routing identifier belongs to a second donor-CU topology domain.

4. A routing device configured as a child node of an IAB node, When an IAB node detects an RLF, a receiving unit receives RLF instruction information from the IAB node, A processing unit that determines, based on the RLF instruction information, that the link corresponding to the IAB node is unavailable, and if an egress link is available, selects the egress link for uplink data, is included. The processing unit selects an egress link for the uplink data, If a donor-CU header rewriting configuration is configured in the child node, and it is determined that the first routing identifier in the BAP header of the uplink data matches the ingress routing identifier in the donor-CU header rewriting configuration, then, based on the donor-CU header rewriting configuration, the first routing identifier in the BAP header of the uplink data is replaced with the corresponding second routing identifier. If the second routing table of the child node contains a routing entry that satisfies the first condition, the egress link corresponding to the next hop address in the routing entry is set as the first egress link of the uplink data, The first condition means that the routing identifier in the routing entry matches the second routing identifier, and that an egress link corresponding to the next hop address in the routing entry is available. The first routing identifier belongs to the first donor-CU topology domain, and the second routing identifier belongs to the second donor-CU topology domain. The apparatus wherein the first donor-CU is a donor-CU that has established an F1 association with the IAB node, and the second donor-CU is a donor-CU that has not established an F1 association with the IAB node.

5. If the link corresponding to the IAB node is an ingress link corresponding to the first donor-CU, the processing unit determines that the link corresponding to the IAB node is not available for the routing entry in the first routing table. The apparatus according to claim 4, wherein the first donor-CU is a donor-CU that has established an F1 association with the IAB node, and the first routing table is a routing table for the first donor-CU topology domain.

6. If the link corresponding to the IAB node is an ingress link corresponding to a second donor-CU, the processing unit determines that the link corresponding to the IAB node is not available for the routing entry in the second routing table. The apparatus according to claim 4, wherein the second donor-CU is a donor-CU that has not established an F1 association with the IAB node, and the second routing table is a routing table for the second donor-CU topology domain.

7. If the second routing table of the child node does not contain a routing entry that satisfies the first condition, the processing unit determines whether or not the second routing table of the child node contains a routing entry that satisfies the third condition. If the second routing table of the child node contains a routing entry that satisfies the third condition, the processing unit sets the egress link corresponding to the next hop address in the routing entry as the egress link for the data packet of the uplink data. The apparatus according to claim 4, wherein the third condition means that the destination BAP address of the routing identifier in the routing entry matches the destination BAP address of the second routing identifier, and an egress link corresponding to the next hop address in the routing entry is available.

8. If the second routing table of the child node does not contain a routing entry that satisfies the third condition, the processing unit determines whether or not the second routing table of the child node contains a routing entry that satisfies the fifth condition. If the second routing table of the child node contains a routing entry that satisfies the fifth condition, the processing unit changes the second routing identifier in the header of the uplink data packet to the routing identifier in the routing entry, and sets the egress link corresponding to the next hop address in the routing entry as the egress link of the uplink data packet. The apparatus according to claim 7, wherein the fifth condition includes that an egress link corresponding to the address of the next hop in the routing entry is available.

9. If there is no routing entry in the second routing table of the child node that satisfies the fifth condition, the processing unit determines whether or not the first routing configuration is configured in the child node. If the child node has the first routing configuration configured, the processing unit determines whether or not there is a routing entry in the child node's first routing table that satisfies the seventh condition. If the first routing table of the child node contains a routing entry that satisfies the seventh condition, the processing unit changes the second routing identifier in the header of the uplink data packet to the routing identifier in the routing entry, and sets the egress link corresponding to the next hop address in the routing entry as the egress link of the uplink data packet. The apparatus according to claim 8, wherein the seventh condition includes that an egress link corresponding to the address of the next hop in the routing entry is available.

10. The apparatus according to claim 4, further comprising a transmission unit that transfers the RLF instruction information to the child node of the child node.

11. If the child node is configured with a donor-CU uplink routing substitution table, and the RLF instruction information is received from the ingress link corresponding to the second donor-CU, and the RLF instruction information includes a third routing identifier, The processing unit determines a fourth routing identifier that needs to be replaced with a third routing identifier based on the donor-CU uplink routing replacement table. The transmitting unit transmits RLF instruction information to the child node's child node, and the RLF instruction information includes the fourth routing identifier. The apparatus according to claim 10, wherein the third routing identifier belongs to the second donor-CU topology domain, and the fourth routing identifier belongs to the first donor-CU topology domain.

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