A communication method and a communication device

Abstract

The application provides a communication method and a communication device. The method comprises the following steps: after a first IAB node receives a first RRC message from an IAB donor CU and the first IAB node switches from a source parent node of the first IAB node to a target parent node of the first IAB node according to the first RRC message, the first IAB node sends a second RRC message to a second IAB node to trigger the second IAB node to perform a transport network layer migration according to the second RRC message. The second IAB node avoids starting to perform the transport network layer migration before the first IAB node successfully switches to access the target parent node of the first IAB node, so that the second IAB node can avoid migration failure caused by the premature execution of the transport network layer migration, thereby reducing the influence of the service time delay of the terminal served by the IAB node, and improving the communication efficiency.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a communication method and communication device. Background Technology

[0002] Currently, in integrated access and backhaul (IAB) networks, topology updates are permitted. For example, an IAB node may switch from a source parent node to a target parent node. After the switch, the transport network layer (TNL) migration of the IAB node and its subordinate nodes is further completed, thus fulfilling the topology update requirement. The subordinate nodes of this IAB node are also IAB nodes, including its child nodes, grandchild nodes, etc.

[0003] However, there is currently no good method for determining when to trigger the transport network layer migration of the subordinate nodes of the IAB node in order to reduce the impact of service latency on the terminals served by the IAB node. Summary of the Invention

[0004] This application provides a communication method and a communication device to trigger IAB nodes to perform transport network layer migration at appropriate times, thereby reducing the impact of service latency on terminals served by IAB nodes and improving communication efficiency.

[0005] In a first aspect, embodiments of this application provide a communication method, which can be executed by a first IAB node or a module (such as a chip) applied in the first IAB node, where the first IAB node is a migration IAB node. Taking the execution of this method by the first IAB node as an example, the first IAB node determines that a first condition is met, the first condition including: the first IAB node receives a first RRC message from the IAB host CU, and the first IAB node switches from its source parent node to its target parent node according to the first RRC message. When the first condition is met, the first IAB node sends indication information to a second IAB node, the indication information being used to trigger a second RRC message in the second IAB node to take effect. Alternatively, when the first condition is met, the first IAB node sends the second RRC message to the second IAB node. The first RRC message includes first configuration information used for transport network layer migration between the first IAB node and the IAB host CU, and the second RRC message includes second configuration information used for transport network layer migration between the second IAB node and the IAB host CU. The second IAB node is a child node of the first IAB node. The source parent node and the target parent node are connected to different IAB host DUs. The first IAB node is connected to the IAB host CU through the different IAB host DUs before and after the switch.

[0006] According to the above scheme, after the first IAB node receives the first RRC message from the IAB host CU and switches from its source parent node to its target parent node based on the first RRC message, it sends a second RRC message to the second IAB node to trigger the second IAB node to perform transport network layer migration based on the second RRC message. This avoids the second IAB node starting to perform transport network layer migration before the first IAB node successfully switches to the target parent node connected to the first IAB node. Therefore, it can avoid the second IAB node failing to migrate due to prematurely performing transport network layer migration, thereby reducing the impact on service latency of the terminals served by the IAB access point and improving communication efficiency.

[0007] As one possible implementation, the first condition further includes: the first IAB node has not received first information from the IAB host CU, the first information being used for data transmission after the first IAB node is switched, the first information including one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0008] According to the above scheme, the first IAB node is required to send the second RRC message to the second IAB node before receiving the first information from the IAB host node -CU. This allows the second IAB node to start performing transport network layer migration as early as possible, thereby reducing the impact of service latency on the terminals served by the IAB node and improving communication efficiency.

[0009] As one possible implementation, the first condition further includes: the first IAB node has not completed the transport network layer migration between the first IAB node and the IAB host CU according to the first configuration information.

[0010] According to the above scheme, the first IAB node is prevented from sending the second RRC message to the second IAB node only after the first IAB node has completed the transport network layer migration. Therefore, the service interruption delay of the terminal is avoided due to the second IAB node performing the transport network layer migration too late.

[0011] As one possible implementation, the source parent node and the target parent node, connected to different IAB host DUs, all belong to the same IAB host CU. The first configuration information includes a first BAP routing identifier. The first IAB node receives uplink data packets containing a second BAP routing identifier. When the BAP address in the second BAP routing identifier is the same as the BAP address in the first BAP routing identifier, the first IAB node sends the uplink data packet according to the first BAP routing identifier.

[0012] According to the above scheme, after the migrated IAB node switches to the target parent node, and before the transport network layer migration between the migrated IAB node and the IAB host node - CU is completed, if the BAP address in the received uplink data packet is the same as the BAP address in the first BAP routing identifier, the first IAB node can use the first BAP routing identifier to route the uplink data packet. This ensures successful transmission of received uplink data packets and avoids packet loss. Furthermore, it enables early transmission of uplink data packets, reducing service interruption latency at the terminal.

[0013] As one possible implementation, when the BAP address in the second BAP route identifier is the same as the BAP address in the first BAP route identifier, and the first IAB node has not received the first information from the IAB host CU, the first IAB node sends the uplink data packet according to the first BAP route identifier. The first information is used for data transmission after the first IAB node switches over, and the first information includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0014] According to this scheme, since the aforementioned data packets cannot be routed based on the BAP routing configuration information on the target path before receiving the BAP routing configuration information on the target path, the method described in this application can be used to route the received uplink data packets using the first IAB node's own first BAP routing identifier, thereby ensuring successful transmission of the received uplink data packets and avoiding packet loss. As one possible implementation, the IAB host DU connected to the source parent node belongs to the IAB host CU, and the IAB host DU connected to the target parent node belongs to another IAB host CU different from the first IAB host CU. The first configuration information includes a first BAP routing identifier. The first IAB node receives uplink data packets containing a second BAP routing identifier. When the BAP address in the second BAP routing identifier is the same as the BAP address assigned to the first IAB node by the IAB host CU, the first IAB node replaces the second BAP routing identifier in the downlink data packet with the first BAP routing identifier. The first IAB node then sends the uplink data packet based on the first BAP routing identifier.

[0015] According to the above scheme, after the migrated IAB node switches to the target parent node, and before the transport network layer migration between the migrated IAB node and the IAB host node - CU is completed, when the first IAB node receives an uplink data packet, if the BAP address in the uplink data packet is the same as the BAP address of the first IAB node, it indicates that the first IAB node needs to replace the BAP routing identifier in the uplink data packet. Therefore, the first IAB node then uses its own first BAP routing identifier to route the uplink data packet. This ensures successful transmission of received uplink data packets and avoids packet loss. Furthermore, it enables uplink data packet transmission as early as possible, reducing service interruption latency at the terminal.

[0016] As one possible implementation, when the BAP address in the second BAP route identifier is the same as the BAP address of the first IAB node, and the first IAB node has not received the first information from the IAB host CU, the first IAB node sends the uplink data packet according to the first BAP route identifier. The first information is used for data transmission after the first IAB node's handover, and the first information includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0017] According to this scheme, since the above-mentioned data packets cannot be routed based on the BAP routing configuration information on the target path before the BAP routing configuration information is received on the target path, the above-mentioned method of this application can be used to route the received uplink data packets by the first IAB node using its own first BAP routing identifier, thereby ensuring the successful transmission of the received uplink data packets and avoiding packet loss.

[0018] As one possible implementation, the first configuration information also includes the identifier of the BHRLC CH. The first IAB node determines the next-hop node corresponding to the first BAP route identifier. The first IAB node sends the uplink data packet to the next-hop node on the BHRLC CH.

[0019] As one possible implementation, the next-hop node is the default parent node of the first IAB node. Alternatively, the first configuration information may also include the identifier of the next-hop node.

[0020] As one possible implementation, the source parent node and the target parent node, connected to different IAB host DUs, all belong to the same IAB host CU. The first IAB node receives downlink data packets containing a third BAP route identifier. The first IAB node determines that it has received the first RRC message and has not received first information from the IAB host CU. Based on the BAP address in the third BAP route identifier, it determines its next-hop node. The first IAB node then sends the downlink data packet to the next-hop node. The first information is used for data transmission after the first IAB node's handover and includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0021] According to the above scheme, after the migrated IAB node switches to the target parent node, and before the transport network layer migration between the migrated IAB node and the IAB host node - CU is completed, when the first IAB node receives a downlink data packet and determines that the rerouting trigger condition is met, it performs rerouting based on the BAP address in the third BAP routing identifier. This ensures the successful transmission of received downlink data packets and avoids packet loss. Furthermore, it enables the early transmission of downlink data packets, reducing service interruption latency at the terminal.

[0022] As one possible implementation, the source parent node connects to an IAB host DU belonging to that IAB host CU, and the target parent node connects to an IAB host DU belonging to another IAB host CU different from that IAB host CU. The first configuration information includes a fourth BAP routing identifier. The first IAB node receives a downlink data packet containing a third BAP routing identifier, the BAP address in which is the BAP address of the first IAB node. The first IAB node replaces the third BAP routing identifier in the downlink data packet with the fourth BAP routing identifier. The first IAB node determines that it has received the first RRC message and has not received the first information from the IAB host CU. Based on the BAP address in the fourth BAP routing identifier, it determines the next-hop node of the first IAB node. The first IAB node sends the downlink data packet to the next-hop node. The first information is used for data transmission after the first IAB node switches over, and the first information includes one or more of BAP routing mapping configuration, BH RLC CH mapping configuration, or BAP routing identifier configuration.

[0023] According to the above scheme, after the migrated IAB node switches to the target parent node, and before the transport network layer migration between the migrated IAB node and the IAB host node - CU is completed, when the first IAB node receives a downlink data packet and determines that the rerouting trigger condition is met, it performs rerouting based on the BAP address in the fourth BAP routing identifier. This ensures the successful transmission of received downlink data packets and avoids packet loss. Furthermore, it enables the transmission of downlink data packets as early as possible, reducing service interruption latency at the terminal.

[0024] As one possible implementation, the first configuration information includes a new IP address assigned to the first IAB node.

[0025] As one possible implementation, the first configuration information includes a first BAP route identifier. The first IAB node determines the next-hop node corresponding to the first BAP route identifier. The first IAB node sends an uplink data packet to the next-hop node, the uplink data packet containing the first BAP route identifier.

[0026] According to the above scheme, after the migrated IAB node switches to the target parent node, and before the transport network layer migration between the migrated IAB node and the IAB host node - CU is completed, the first IAB node generates an uplink data packet and routes the uplink data packet using the first BAP routing identifier. This ensures successful transmission of received uplink data packets and avoids packet loss. Furthermore, it enables early transmission of uplink data packets, reducing service interruption latency at the terminal.

[0027] Secondly, embodiments of this application provide a communication method, which can be executed by a first IAB node or a module (such as a chip) applied in the first IAB node, where the first IAB node is a subordinate node of a migrating IAB node. Taking the execution of this method by the first IAB node as an example, the first IAB node determines that a first condition is met, the first condition including: the first IAB node receives a first indication information or a first RRC message from a second IAB node, the second IAB node being the parent node of the first IAB node, and the first indication information being used to trigger the first RRC message in the first IAB node to take effect. When the first condition is met, the first IAB node sends a second indication information to a third IAB node, the second indication information being used to trigger the second RRC message in the third IAB node to take effect. Alternatively, when the first condition is met, the first IAB node sends the second RRC message to the third IAB node, the third IAB node being a child node of the first IAB node. The first RRC message includes first configuration information, which is used for the transport network layer migration between the first IAB node and the IAB host CU. The second RRC message includes second configuration information, which is used for the transport network layer migration between the third IAB node and the IAB host CU. The first IAB node connects to the IAB host CU through different IAB host DUs before and after the transport network layer migration.

[0028] According to the above scheme, after receiving the first RRC message or the first indication information from the second IAB node, the first IAB node can start performing the transport network layer migration on the one hand, and immediately send the second RRC message or the second indication information to the child nodes of the first IAB node on the other hand. This can trigger the child nodes of the first IAB node to start performing the transport network layer migration as early as possible, which can avoid the terminal's service interruption delay caused by the child nodes of the first IAB node performing the transport network layer migration too late. This reduces the impact of service delay on the terminal served by the IAB contact point and can improve communication efficiency.

[0029] As one possible implementation, the first condition further includes: the first IAB node did not receive first information from the second IAB node, the first information being used for data transmission of the first IAB node after migration at the transport network layer, the first information including one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0030] According to the above scheme, the first IAB node is required to send the second RRC message to the third IAB node before receiving the first information from the second IAB node. This allows the third IAB node to start performing the transport network layer migration as early as possible, avoiding excessive service interruption delays caused by the first IAB node's child nodes performing the transport network layer migration too late. This reduces the impact of service delays on the terminals served by the IAB node and improves communication efficiency.

[0031] As one possible implementation, the first condition further includes: the first IAB node has not completed the transport network layer migration between the first IAB node and the IAB host CU according to the first configuration information.

[0032] According to the above scheme, the first IAB node is prevented from sending the second RRC message to the third IAB node only after the first IAB node has completed the transport network layer migration. Therefore, the service interruption delay of the terminal caused by the third IAB node performing the transport network layer migration too late can be avoided, thereby reducing the impact of service delay on the terminal of the IAB node service and improving communication efficiency.

[0033] As one possible implementation, the first configuration information includes a first BAP route identifier. The first IAB node receives an uplink data packet containing a second BAP route identifier. When the BAP address in the second BAP route identifier is the same as the BAP address in the first BAP route identifier, the first IAB node sends the uplink data packet according to the first BAP route identifier.

[0034] According to the above scheme, after the migrated IAB node switches to the target parent node, and before the transport network layer migration between the migrated IAB node and the IAB host node - CU is completed, if the BAP address in the received uplink data packet is the same as the BAP address in the first BAP routing identifier, the first IAB node can use the first BAP routing identifier to route the uplink data packet. This ensures successful transmission of received uplink data packets and avoids packet loss. Furthermore, it enables early transmission of uplink data packets, reducing service interruption latency at the terminal.

[0035] As one possible implementation, when the BAP address in the second BAP route identifier is the same as the BAP address in the first BAP route identifier, and the first IAB node has not received the first information from the second IAB node, the first IAB node sends the uplink data packet according to the first BAP route identifier. The first information is used for data transmission after the first IAB node switches over, and the first information includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0036] According to this scheme, since the above-mentioned data packets cannot be routed based on the BAP routing configuration information on the target path before the BAP routing configuration information is received on the target path, the above-mentioned method of this application can be used to route the received uplink data packets by the first IAB node using its own first BAP routing identifier, thereby ensuring the successful transmission of the received uplink data packets and avoiding packet loss.

[0037] As one possible implementation, the first configuration information also includes the identifier of the BHRLC CH. The first IAB node determines the next-hop node corresponding to the first BAP route identifier. The first IAB node sends the uplink data packet to the next-hop node on the BHRLC CH.

[0038] As one possible implementation, the next-hop node is the default parent node of the first IAB node. Alternatively, the first configuration information may also include the identifier of the next-hop node.

[0039] As one possible implementation, the first IAB node receives a downlink data packet containing a third BAP route identifier. The first IAB node determines that it has received the first RRC message and has not received the first information from the IAB host CU. Based on the BAP address in the third BAP route identifier, the first IAB node determines its next-hop node. The first IAB node then sends the downlink data packet to the next-hop node. The first information is used for data transmission after the first IAB node's handover, and includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0040] According to the above scheme, after the migrated IAB node switches to the target parent node, and before the transport network layer migration between the migrated IAB node and the IAB host node - CU is completed, when the first IAB node receives a downlink data packet and determines that the rerouting trigger condition is met, it performs rerouting based on the BAP address in the third BAP routing identifier. This ensures the successful transmission of received downlink data packets and avoids packet loss. Furthermore, it enables the early transmission of downlink data packets, reducing service interruption latency at the terminal.

[0041] As one possible implementation, the first configuration information includes a new IP address assigned to the first IAB node.

[0042] Thirdly, embodiments of this application provide a communication device, which can be an IAB node or a chip for an IAB node. This device has the function of implementing any of the methods described in the first to second aspects. This function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-described functions.

[0043] Fourthly, embodiments of this application provide a communication device, including a processor and a memory; the memory is used to store computer instructions, and when the device is running, the processor executes the computer instructions stored in the memory to cause the device to perform any of the implementation methods in the first to second aspects described above.

[0044] Fifthly, embodiments of this application provide a communication device including units or means for performing various steps of any of the implementation methods in the first to second aspects described above.

[0045] Sixthly, embodiments of this application provide a communication device, including a processor and an interface circuit. The processor is configured to communicate with other devices via the interface circuit and execute any of the implementation methods described in the first to second aspects. The processor may include one or more devices.

[0046] In a seventh aspect, embodiments of this application provide a communication device including a processor coupled to a memory. The processor is configured to invoke a program stored in the memory to execute any of the implementation methods described in the first to second aspects. The memory may be located within or outside the device. Furthermore, the processor may be one or more.

[0047] Eighthly, embodiments of this application also provide a computer-readable storage medium storing instructions that, when executed on a communication device, cause any of the implementation methods of the first to second aspects described above to be performed.

[0048] Ninthly, embodiments of this application also provide a computer program product, which includes a computer program or instructions that, when executed by a communication device, cause any of the implementation methods in the first to second aspects described above to be executed.

[0049] In a tenth aspect, embodiments of this application also provide a chip system, including: a processor for executing any of the implementation methods in the first to second aspects described above. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of an IAB standalone networking scenario;

[0051] Figure 2 This is a schematic diagram of an IAB non-standalone networking scenario;

[0052] Figure 3 This is a schematic diagram of the IAB network user plane protocol stack.

[0053] Figure 4 This is a schematic diagram of the IAB network control plane protocol stack.

[0054] Figure 5 This is a schematic diagram of topology updates within the IAB network host.

[0055] Figure 6 A schematic diagram of cross-host topology updates in an IAB network;

[0056] Figure 7(a) is a flowchart illustrating the communication method provided in an embodiment of this application;

[0057] Figure 7(b) is a flowchart illustrating the communication method provided in an embodiment of this application;

[0058] Figure 8(a) is a flowchart illustrating the communication method provided in an embodiment of this application;

[0059] Figure 8(b) is a flowchart illustrating the communication method provided in an embodiment of this application;

[0060] Figure 9 A flowchart illustrating the data transmission method provided in an embodiment of this application;

[0061] Figure 10 A flowchart illustrating the data transmission method provided in an embodiment of this application;

[0062] Figure 11 A flowchart illustrating the data transmission method provided in an embodiment of this application;

[0063] Figure 12 A flowchart illustrating the data transmission method provided in an embodiment of this application;

[0064] Figure 13 A flowchart illustrating the data transmission method provided in an embodiment of this application;

[0065] Figure 14 A schematic diagram of a communication device provided in an embodiment of this application;

[0066] Figure 15 This is a schematic diagram of a communication device provided in an embodiment of this application. Detailed Implementation

[0067] Compared to fourth-generation (4G) mobile communication systems, fifth-generation (5G) mobile communication places more stringent demands on all aspects of network performance. For example, it requires a 1000-fold increase in capacity, wider coverage, and ultra-high reliability and ultra-low latency. On the one hand, considering the abundance of high-frequency carrier resources, the use of high-frequency small cell networks is becoming increasingly popular in hotspot areas to meet the ultra-high capacity demands of 5G. However, high-frequency carriers have poor propagation characteristics, suffer severe attenuation due to obstruction, and have limited coverage, thus requiring a large-scale, dense deployment of small cells. Correspondingly, providing fiber optic backhaul for these densely deployed small cells is costly and difficult to implement, necessitating an economical and convenient backhaul solution. On the other hand, from the perspective of wide coverage requirements, providing network coverage in remote areas presents challenges due to the difficulty and cost of fiber optic deployment, also requiring flexible and convenient access and backhaul solutions. IAB technology offers a solution to these two problems: both its access link and backhaul link utilize wireless transmission schemes, avoiding fiber optic deployment.

[0068] refer to Figure 1 This diagram illustrates an IAB standalone (SA) network scenario. Both IAB nodes and user equipment (UEs) establish connections to the network via a New Radio (NR) interface. In an IAB network, an IAB node, also known as a relay node (RN), provides radio access services to the UE. The UE's service data is transmitted from the IAB node to the IAB donor node via a radio backhaul link. In this application, the IAB donor node can also be referred to as a host node or a donor gNodeB (DgNB).

[0069] An IAB node consists of a mobile termination (MT) portion and a distributed unit (DU) portion. The MT portion of an IAB node possesses some or all of the functions of a UE and can be used to provide data backhaul to its child nodes. The DU portion of an IAB node can be used to provide access services to its child nodes. The MT portion of an IAB node can be abbreviated as IAB-MT, and the DU portion as IAB-DU. An IAB node can communicate with its parent node through its MT portion; in this case, the IAB node is considered a UE. An IAB node can communicate with its child nodes through its DU portion; in this case, the IAB node is considered a network device. The child nodes of an IAB node can be another IAB node or a regular UE.

[0070] IAB nodes can be divided into access IAB nodes and intermediate IAB nodes. The IAB node to which the UE accesses is called the access IAB node, and the IAB nodes on the path between the access IAB node and the IAB host node are called intermediate IAB nodes. For example... Figure 1 In this context, IAB nodes 4 and 5 are called access IAB nodes, while IAB nodes 1, 2, and 3 are called intermediate IAB nodes.

[0071] The IAB host node can be an access network element with some or all of the functions of a base station, or it can be an access network element that includes a centralized unit (CU) and a DU. The IAB host node can connect to the core network serving the UE (e.g., a 5G core network) and provide radio backhaul functionality for the IAB node. In this embodiment, the CU in the IAB host node can be referred to as IAB host CU, IAB host node-CU, host node-CU, or donor CU, and the DU in the IAB host node can be referred to as IAB host DU, IAB host node-DU, host node-DU, or donor DU. The donor CU may also have a separate control plane (CP) and user plane (UP) configuration; for example, the donor CU may include a CU-CP and at least one CU-UP.

[0072] In this application, the terminal may also be referred to as a terminal device, UE, mobile station, mobile terminal, etc. Terminals can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, etc. Terminals can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. The embodiments of this application do not limit the specific technology or device form used in the terminal.

[0073] In the current 5G standard, considering the limited coverage of high-frequency bands, multi-hop networking can be used in IAB networks to ensure network coverage performance. Furthermore, considering the reliability requirements of service transmission, IAB nodes can support dual connectivity (DC) or multi-connectivity to handle potential anomalies in the backhaul link, such as link interruptions, blockages, and load fluctuations, thus improving transmission reliability. Therefore, IAB networks support both multi-hop and multi-connectivity networking. Between the UE served by an IAB node and the IAB host node, there exists at least one transmission path composed of multiple links. A transmission path contains multiple nodes, such as the UE, one or more IAB nodes, and the IAB host node (if the IAB host node is in a separate CU and DU configuration, then the IAB host node is replaced by IAB host node-DU and IAB host node-CU). Each IAB node considers the adjacent nodes providing access and backhaul services to it as its parent nodes; correspondingly, each IAB node can be considered a child node of its parent node.

[0074] For example, Figure 1 In this diagram, the IAB host node is the parent node of IAB node 1, and IAB node 1 is a child node of the IAB host node. IAB node 1 is the parent node of IAB nodes 2 and 3, and IAB nodes 2 and 3 are child nodes of IAB node 1. IAB node 2 is the parent node of IAB nodes 4 and 5, and IAB nodes 4 and 5 are child nodes of IAB node 2. IAB node 3 is the parent node of IAB node 4, and IAB node 4 is a child node of IAB node 3.

[0075] In the uplink direction, the UE's uplink data packets can be transmitted to the IAB host node via one or more IAB nodes, and then sent by the IAB host node to the mobile gateway device (e.g., the user plane function (UPF) in the 5G core network). In the downlink direction, after receiving the downlink data packets from the mobile gateway device, the IAB host node sends them to the UE through the IAB nodes.

[0076] Figure 1 The IAB standalone networking scenario shown is merely an example. In IAB scenarios combining multi-hop and multi-connection architectures, there are many other possibilities, such as... Figure 1 The IAB host node in the UE can form a dual connection with another IAB host node to provide services to the UE. That is, the UE supports dual connections, one of which is the UE connecting through... Figure 1 The IAB node in the middle is connected to Figure 1 In the cell served by the IAB host node -DU, another connection 2 is the connection established between the UE and the IAB node X. The IAB host connected to the IAB node X is different from the IAB host node corresponding to the above connection 1.

[0077] refer to Figure 2 This diagram illustrates a non-standalone (NSA) network architecture for IAB (Integrated Device Architecture). IAB nodes support dual connectivity for both 4G and 5G networks. The long-term evolution (LTE) base station (eNB) is the master eNB (MeNB). The eNB provides LTE air interface (LTE Uu) connectivity to the IAB nodes and establishes an S1 interface with the 4G core network (Evolved Packet Core, EPC) for user plane and control plane transmissions. The IAB host node is the secondary base station. The IAB host node can be a 5G gNB, providing NR air interface (NR Uu) connectivity to the IAB nodes and establishing an S1 interface with the EPC for user plane transmissions. The UE connects to the master base station (eNB) via the LTE Uu interface and to the secondary base station (which can be an IAB node or the IAB host node) via the NR Uu interface.

[0078] It should be noted that, Figure 2 This is just a networking example; NSA scenarios in IAB networks also support multi-hop IAB networking, for example... Figure 2 One or more IAB nodes can be added between the UE and the IAB node, that is, the IAB node can connect to the IAB host node through a multi-hop radio backhaul link.

[0079] In current IAB networks, a new protocol layer has been introduced into the wireless backhaul link, namely the backhaul adaptation protocol (BAP) layer. The BAP layer is located above the radio link control (RLC) layer and can be used to implement functions such as packet routing and bearer mapping in the wireless backhaul link.

[0080] An F1 interface is established between the DU portion of the IAB node and the IAB host node-CU. The F1 interface supports user plane protocols (F1-U) and control plane protocols (F1-C). The user plane protocols include one or more of the following protocols: General Packet Radio Service (GPRS) tunneling protocol user plane (GTP-U), user datagram protocol (UDP), and Internet protocol (IP). The control plane protocols include one or more of the following protocols: F1 application protocol (F1AP), stream control transport protocol (SCTP), and IP protocol.

[0081] refer to Figure 3 This is a schematic diagram of the IAB network user plane protocol stack. If the IAB host node adopts a CP-UP separation architecture, then the IAB node (such as...) Figure 3 An F1-U interface is established between the DU portion of IAB node 1 and IAB node 2 (as shown) and the IAB host node -CU-UP. Furthermore, for access IAB nodes, a per-UE bearer GTP tunnel is also established on the F1-U interface between the access IAB node and the IAB host node -CU-UP. In other words, each UE DRB established on the interface between the UE and the DU of the access IAB node corresponds to a separate GTP tunnel on the F1-U interface between the access IAB node and the IAB host node -CU-UP.

[0082] refer to Figure 4 This is a schematic diagram of the IAB network control plane protocol stack. If the IAB host node adopts a CP-UP separation architecture, then the IAB node (such as...) Figure 4An F1-C interface is established between the DU portion of IAB node 1 and IAB node 2 (as shown) and the IAB host node-CU-CP. The UE's radio resource control (RRC) messages are encapsulated in the F1AP messages of the F1-C interface for transmission.

[0083] Currently, IAB nodes are allowed to perform topology updates within the scope of a single IAB host node - CU service. (Reference) Figure 5 This is a diagram illustrating the topology update within the IAB network host. IAB node 1, acting as a migrating IAB node, connects to the source parent node before the topology update. However, due to factors such as deteriorating link quality or load balancing between IAB node 1 and the source parent node (i.e., IAB node 5), the IAB node needs to perform a topology update. After the topology update, IAB node 1 connects to the target parent node (i.e., IAB node 6) and communicates with the IAB host node via the target parent node.

[0084] In an IAB network, an IAB node's IP address is related to the IAB host node (DU) it connects to. Therefore, if, during a topology update, the IAB host node (DU) to which the target parent node of IAB node 1 connects is different from the IAB host node (DU) to which the source parent node of IAB node 1 connects, then IAB node 1 needs to be configured with different IP addresses before and after the migration. That is, when IAB node 1 connects to the source parent node, its IP address is related to IAB host node (DU) 1, and may even be assigned by IAB host node (DU) 1. When IAB node 1 connects to the target parent node, its IP address is related to IAB host node (DU) 2, and may even be assigned by IAB host node (DU) 2.

[0085] In addition to IAB node 1, its subordinate nodes, such as its child node IAB node 2 and grandchild node IAB node 4, also need to be configured with new IP addresses after connecting to the IAB host node - DU 2 following IAB node 1.

[0086] In this embodiment, "grandchild node" refers to a child node of a child node. Figure 5 For example, the child node of IAB node 1 includes IAB node 2, and the child node of IAB node 2 includes IAB node 4. Therefore, IAB node 4 is the grandchild node of IAB node 1, and correspondingly, IAB node 1 can be called the grandparent node of IAB node 4. This is explained here for simplicity and will not be repeated later.

[0087] In this embodiment of the application, "subordinate nodes of the migrated IAB node" includes the child nodes of the migrated IAB node and nodes below the child nodes, or it can be understood as the IAB nodes on the transmission path between the UE and the migrated IAB node. Specifically, the subordinate nodes of the migrated IAB node include the child nodes, grandchild nodes, child nodes of grandchild nodes, grandchild nodes of grandchild nodes, and so on. Figure 5 For example, IAB node 1 is a migrated IAB node, and its subordinate nodes include IAB node 2, IAB node 3, and IAB node 4. In this embodiment, the subordinate nodes of the migrated IAB node are also referred to as subordinate IAB nodes of the migrated IAB node, or downstream nodes of the migrated IAB node, or downstream IAB nodes of the migrated IAB node. This is a consistent explanation here and will not be repeated later. After configuring a new IP address, the IAB node can use this new IP address to establish a new transport network layer association with the IAB host node - CU, and re-negotiate Internet Protocol Security (IPsec) security. Then, the F1-C connection between the DU part of the IAB node and the GTP-U tunnel of F1-U between the IAB host node and CU is migrated to the new transmission path, and the new IP address is used on the new transmission path.

[0088] In this embodiment of the application, the process of establishing a Stream Control Transmission Protocol (SCTP) layer connection (or transport network layer coupling, or SCTP coupling) on ​​a new transmission path using a new IP address for the IAB node, and / or re-negotiating IPsec security, is called the transport network layer migration of the IAB node.

[0089] The transport network layer migration of the IAB node may also include any one or more of the following: placing the control plane of the IAB node's F1 interface on an SCTP layer coupling established on a new transport path; and migrating the user plane of the IAB node's F1 interface to a new transport path. Specifically, when the control plane of the IAB node's F1 interface is placed on an SCTP layer coupling established on a new transport path, a new IP address will be used in the new SCTP layer coupling. When the user plane of the IAB node's F1 interface is migrated to a new transport path, a new IP address will be used in the GTP-U tunnel of the F1-U.

[0090] Migrating an IAB node and its subordinate nodes both require performing a transport network layer migration.

[0091] The above describes the process of an IAB node performing topology updates within the scope of an IAB host node - CU service. In another scenario, there is also the issue of topology updates during IAB node migration across IAB host nodes. (References) Figure 6 This diagram illustrates a cross-host topology update in an IAB network. IAB node 1 is the migrating IAB node, and IAB host node 1 is the source IAB host node, comprising IAB host node-CU 1 and IAB host node-DU 1. IAB host node 2 is the target IAB host node, comprising IAB host node-CU 2 and IAB host node-DU 2. Before the topology update, the migrating IAB node connects to the source parent node (IAB node 5), which is managed by the source IAB host node. After the topology update, the migrating IAB node connects to the target parent node (IAB node 6), which is managed by the target IAB host node.

[0092] In this embodiment of the application, the migrating IAB node in the cross-host topology update scenario of the IAB network can also be called a boundary node. The source parent node and the target parent node of the boundary node are connected to different IAB host nodes -DU, and the different IAB host nodes -DU belong to different IAB host nodes -CU, or in other words, there is an F1 interface between the different IAB host nodes -DU and the different IAB host nodes -CU.

[0093] As one implementation approach, one could consider updating only the MT portion of the migrated IAB node to be managed by the target IAB host node (or migrating the RRC connection of the MT portion of the migrated IAB node to the target IAB host node), while the DU portion of the migrated IAB node and its subordinate nodes remain controlled by the source IAB host node (or the DU portion of the migrated IAB node and its subordinate nodes remain connected to the source IAB host node). For example, refer to... Figure 6 Before the topology update, IAB node 1 and its subordinate nodes were managed by IAB host node 1. After the topology update, the MT portion of IAB node 1 is managed by IAB host node 2, while the DU portion of IAB node 1 and its subordinate nodes remain managed by IAB host node 1. Based on this implementation method, since the parent node of the migrated IAB node is updated, the transmission path also changes. Therefore, after the topology update, the F1 connection between the DU portion of the migrated IAB node and IAB host node CU1 needs to be migrated to the new transmission path, as shown in the figure. Figure 6 As shown, a transport network layer migration process is therefore required. Correspondingly, if the child nodes of the IAB node are migrated, a transport network layer migration process also needs to be performed. That is, both migrating the IAB node and migrating its subordinate nodes require a transport network layer migration process.

[0094] As can be seen from the above description, whether it is a topology update within a single IAB host or a topology update across IAB hosts, it is necessary to perform transport network layer migration on the migrated IAB node and its subordinate nodes.

[0095] To achieve the migration of the transport network layer of subordinate nodes of the migrated IAB node, this application provides two different methods, as follows.

[0096] In the first implementation method, the IAB host node (CU) first encapsulates the configuration information required for the subordinate nodes of the migrating IAB node to perform transport network layer migration in RRC messages. These RRC messages from subordinate nodes are then pre-sent from the source transport path to the parent node of each subordinate node. The parent node caches these RRC messages and only sends them to the corresponding subordinate nodes after a first condition (also known as the trigger condition) is met. Upon receiving its own RRC message, each IAB node executes the configuration according to the configuration information in the RRC message and initiates the transport network layer migration.

[0097] In this application embodiment, any RRC message appearing anywhere can be an RRC configuration message or an RRC reconfiguration message. This will be stated uniformly here and will not be repeated later.

[0098] by Figure 5 For example, the migrated IAB node is IAB node 1, and the subordinate nodes of IAB node 1 include IAB node 2, IAB node 3, and IAB node 4. The IAB host node -CU first carries the RRC messages of IAB node 2 and IAB node 3 in the F1AP message sent to IAB node 1 -DU (for example, it can be carried in the same F1AP message or in different F1AP messages). IAB node 1 first caches the RRC messages of IAB node 2 and IAB node 3. Specifically, IAB node 1 can cache the RRC messages of IAB node 2 / 3 according to the indication information in the F1AP message carrying the RRC messages of IAB node 2 / 3. After the first condition is met, IAB Node 1 sends the RRC message of IAB Node 2 to IAB Node 2 and the RRC message of IAB Node 3 to IAB Node 3. After receiving its own RRC message, IAB Node 2 initiates a transport network layer migration according to the configuration information in the RRC message. After receiving its own RRC message, IAB Node 3 initiates a transport network layer migration according to the configuration information in the RRC message.

[0099] Similarly, the IAB host node -CU first carries the RRC message of IAB node 4 in the F1AP message sent to IAB node 2 -DU, and / or in the F1AP message sent to IAB node 3 -DU. IAB node 2 and / or IAB node 3 first cache the RRC message of IAB node 4. After the first condition is met, IAB node 2 and / or IAB node 3 then send the RRC message of IAB node 4 to IAB node 4. After receiving its own RRC message, IAB node 4 initiates a transport network layer migration according to the configuration information in the RRC message.

[0100] In the second implementation method, the IAB host node (CU) encapsulates the configuration information required for the transport network layer migration of subordinate nodes of the migrating IAB node into RRC messages, and pre-sends these subordinate node RRC messages from the source transport path to each subordinate node. Upon receiving its own RRC message, a subordinate node does not immediately activate it. Instead, it initiates the transport network layer migration based on the configuration information in the cached RRC message only after receiving an indication from its parent node to activate the cached RRC message. Specifically, the parent node sends this indication to the subordinate node only after determining that the first condition is met.

[0101] by Figure 5For example, the IAB node to be migrated is IAB node 1, and the subordinate nodes of IAB node 1 include IAB node 2, IAB node 3, and IAB node 4. The IAB host node -CU first carries the RRC message of IAB node 2 in the F1AP message sent to IAB node 1 -DU. IAB node 1 sends the RRC message of IAB node 2 carried in the F1AP message to IAB node 2. IAB node 2 first caches the RRC message but does not take effect on the configuration information in the RRC message. After receiving the indication information sent by IAB node 1, IAB node 2 initiates the transport network layer migration according to the configuration information in the cached RRC message. Similarly, the IAB host node-CU first carries the RRC message of IAB node 3 in an F1AP message sent to IAB node 1-DU. IAB node 1 then sends the RRC message of IAB node 3 carried in the F1AP message to IAB node 3. IAB node 3 first caches the RRC message but does not apply the configuration information in the RRC message initially. After receiving the indication information sent by IAB node 1, IAB node 3 initiates a transport network layer migration based on the configuration information in the cached RRC message. Similarly, the IAB host node-CU first carries the RRC message of IAB node 4 in an F1AP message sent to IAB node 2-DU or IAB node 3-DU. IAB node 2 or IAB node 3 then sends the RRC message of IAB node 4 carried in the F1AP message to IAB node 4. IAB node 4 first caches the RRC message. After receiving the indication information sent by IAB node 2 or IAB node 3, IAB node 4 initiates a transport network layer migration based on the configuration information in the cached RRC message.

[0102] The above implementation methods one and two are applicable to both topology update scenarios within a single IAB network host and topology update scenarios across IAB network hosts.

[0103] Whether the IAB node's transport network layer migration is achieved through either Method 1 or Method 2, the same problem arises: how should the first condition be set? In other words, when should the subordinate nodes of the migrating IAB node be triggered to perform transport network layer migration?

[0104] If the first condition is not set reasonably, it may cause the subordinate nodes of the migrated IAB node to perform transport network layer migration too early. For example, if the subordinate nodes of the migrated IAB node start to attempt to perform transport network layer migration before the migrated IAB node has been connected to the target parent node of the migrated IAB node, it will cause the subordinate nodes of the migrated IAB node to fail to perform transport network layer migration.

[0105] If the first condition is not set reasonably, it may lead to the subordinate nodes of the migrated IAB node performing transport network layer migration too late. For example, if the migrated IAB node has already connected to the target parent node and completed its transport network layer migration, and then the subordinate nodes of the migrated IAB node perform their transport network layer migrations in sequence, it will cause excessively long transport network layer migration waiting delays for these subordinate nodes. Especially when the migrated IAB node has multiple levels of subordinate nodes, the time between the completion of the transport network layer migration by the migrated IAB node and the completion of its subordinate nodes' transport network layer migrations will be very long, significantly impacting the service interruption of UEs (especially UEs accessing the serving cell of subordinate nodes).

[0106] The above analysis shows that the timing of the migration of the IAB node's subordinate nodes to perform the transport network layer migration is very important. Therefore, how to reasonably set the first condition to instruct the migration of the IAB node's subordinate nodes to perform the transport network layer migration at the appropriate time is a problem to be solved.

[0107] To enable the instruction of subordinate nodes of the migrating IAB node to perform transport network layer migration at an appropriate time, this application provides a communication method, which corresponds to the above-described implementation method one. This method provides a first condition that needs to be met when the migrating IAB node sends an RRC message to the child node of the migrating IAB node in the above-described implementation method one.

[0108] This method is applicable to both topology update scenarios within an IAB network host and topology update scenarios across IAB network hosts.

[0109] Referring to Figure 7(a), the method includes the following steps:

[0110] Step 701a: The first IAB node is determined to satisfy the first condition.

[0111] The first IAB node here refers to the migrated IAB node, for example, it could be... Figure 5 or Figure 6 IAB node 1 in the middle.

[0112] The first condition includes:

[0113] Condition 1): The first IAB node receives the first RRC message from the IAB host CU.

[0114] Condition 2): The first IAB node switches from its source parent node to its target parent node according to the first RRC message.

[0115] Both conditions 1) and 2) above need to be met.

[0116] The first RRC message includes first configuration information, which is used for transport network layer migration between the first IAB node and the IAB host CU. The first RRC message can also be referred to as the RRC message of the first IAB node. Figure 5 or Figure 6 For example, when IAB node 1 receives the RRC message from IAB node 1, and IAB node 1 successfully switches from the source parent node (i.e., IAB node 5) to the target parent node (i.e., IAB node 6) based on the RRC message from IAB node 1, then IAB node 1 is determined to meet the first condition.

[0117] In this configuration, the source parent node and target parent node of the first IAB node are connected to different IAB host nodes -DU, and the first IAB node connects to the same IAB host node -CU through these different IAB host nodes -DU before and after the switchover. (Reference) Figure 5 The above illustrates an IAB network host topology update scenario or reference. Figure 6 The illustrated IAB network host topology update scenario shows that the migrating IAB node is IAB node 1. Before the switch, IAB node 1's source parent node was IAB node 5, and IAB node 5 was connected to IAB host node -DU 1. After the switch, IAB node 1's target parent node is IAB node 6, and IAB node 6 is connected to IAB host node -DU 2. IAB host node -DU 1 and IAB host node -DU 2 are different IAB host nodes -DU. Before the switch, IAB node 1 was connected to IAB host node -CU through IAB host node -DU 1. After the switch, IAB node 1 is also connected to IAB host node -CU through IAB host node -DU 2. In this context... Figure 5 In this scenario, IAB node 1's connected IAB host nodes - DU 1 and - DU 2, before and after the switchover, are managed by the same IAB host node - CU. Figure 6 In this scenario, the IAB host nodes - DU 1 and IAB host nodes - DU 2 connected to by IAB node 1 before and after the switchover are managed by different IAB host nodes - CU.

[0118] Step 702a: When the first condition is met, the first IAB node sends a second RRC message to the second IAB node. Correspondingly, the second IAB node receives the second RRC message.

[0119] The second IAB node is a child node of the first IAB node. Figure 5 or Figure 6 For example, the first IAB node is IAB node 1, and the second IAB node is either IAB node 2 or IAB node 3.

[0120] The second RRC message includes second configuration information, which is used for transport network layer migration between the second IAB node and the IAB host CU. The second RRC message can also be referred to as the RRC message of the second IAB node.

[0121] After receiving the second RRC message, the second IAB node can begin performing transport network layer migration. Figure 5 or Figure 6 For example, after IAB node 2 receives the RRC message from IAB node 1, it can begin performing transport network layer migration based on the RRC message. As one implementation method, after receiving the second RRC message, the second IAB node can begin performing transport network layer migration. Specifically, after the MT part of the second IAB node receives the second RRC message, it performs reconfiguration based on the second configuration information in the second RRC message. Then, the MT part of the second IAB node sends an RRC reconfiguration complete message to the IAB host node -CU. Furthermore, if the second RRC message carries configuration information related to transport network layer migration, the second IAB node then performs the transport network layer migration. This explanation uses the second IAB node performing transport network layer migration as an example. Other nodes that need to perform transport network layer migration can also follow this method; this is a unified explanation and will not be elaborated further later.

[0122] According to the above scheme, after the first IAB node receives the first RRC message from the IAB host CU and switches from the source parent node to the target parent node of the first IAB node according to the first RRC message, it sends a second RRC message to the second IAB node to trigger the second IAB node to perform transport network layer migration according to the second RRC message. This avoids the second IAB node starting to perform transport network layer migration before the first IAB node successfully switches to the target parent node of the first IAB node. Therefore, it can avoid the migration failure caused by the second IAB node performing transport network layer migration too early, thereby reducing the impact on the service latency of the UE served by the IAB access point and improving communication efficiency.

[0123] As one implementation method, in addition to the above conditions 1) and 2), the above first condition also includes the following condition 3):

[0124] Condition 3): The first IAB node did not receive the first information from the IAB host node -CU.

[0125] The phrase "the first IAB node did not receive the first information from the IAB host node - CU" can also be understood as "before the first IAB node received the first information from the IAB host node - CU".

[0126] The first information is used for data transmission after the first IAB node handover. This data transmission can be user plane data transmission or control plane signaling transmission. The first information can also be called BAP routing configuration information on the target path, or the updated BAP routing configuration.

[0127] The first information includes one or more of the following: BAP route mapping configuration, backhaul radio link control channel (BH RLC CH) mapping configuration, or BAP route identification configuration.

[0128] The BAP routing mapping configuration includes an updated routing mapping table that the BAP layer of the first IAB node will use based on the new network topology after the first IAB node performs a handover. This updated routing mapping table is used for routing uplink or downlink data packets at the BAP layer after the first IAB node handover. The updated routing mapping table includes one or more entries, each containing a BAP routing ID and the identifier of the next-hop node corresponding to that BAP routing ID (e.g., the BAP address of the next-hop node).

[0129] The BH RLC CH mapping configuration includes the updated BH RLC CH mapping relationship that the BAP layer of the first IAB node will use based on the new network topology after the first IAB node performs a handover. This updated BH RLC CH mapping relationship is used to perform quality of service (QoS) mapping on uplink or downlink data packets at the BAP layer after the first IAB node performs a handover, that is, to select the appropriate BH RLC CH for the uplink or downlink data packets to be sent. As one implementation method, the updated BH RLC CH mapping relationship may include any one or more of the following: the identifier of each GTP-U tunnel of the F1 interface maintained by the first IAB node in uplink data transmission and the identifier of the corresponding BH RLC CH of the egress link; the type information of each non-F1-U service type of the first IAB node in uplink data transmission (specifically, it may be UE-related F1-C interface messages, UE-independent F1-C interface messages, non-F1 type messages, BAP control PDUs, etc.) and the identifier of the corresponding egress link of the BH RLC CH; the identifier of the ingress link of the first IAB node and the identifier of the corresponding egress link of the BH RLC CH in uplink or downlink data transmission.

[0130] The BAP routing identifier configuration includes one or more BAP routing IDs that the BAP layer of the first IAB node will use based on the new network topology after the first IAB node performs a handover. These one or more BAP routing IDs are the BAP routing IDs that the first IAB node will add to the uplink data packets submitted by the first IAB node to the upper protocol layer of the BAP layer (e.g., the IP layer of the first IAB node's DU). As one implementation method, the BAP routing identifier configuration may include any one or more of the following: the identifier of each GTP-U tunnel of the F1 interface maintained by the first IAB node in uplink data transmission and its corresponding BAP routing ID; type information of each non-F1-U service type of the first IAB node in uplink data transmission (specifically, it may be UE-related F1-C interface messages, UE-independent F1-C interface messages, non-F1 type messages, BAP control PDUs, etc.) and their corresponding BAP routing IDs.

[0131] In this application, the identifier of the BHRLC CH of the IAB node's egress link can be jointly identified by the BAP address of the next-hop node of the IAB node corresponding to the egress link and the BHRLC CH ID on the egress link. The identifier of the BHRLC CH of the IAB node's ingress link can be jointly identified by the BAP address of the previous-hop node of the IAB node corresponding to the ingress link and the BHRLC CH ID on the ingress link. The identifier of each GTP-U tunnel of the F1 interface maintained by the IAB node can be jointly identified by the tunnel endpoint identifier (TEID) of the GTP-U tunnel and the upstream destination IP address, wherein the TEID is assigned by the IAB host node-CU (in the scenario where the IAB host node-CU is separated from the CP-UP, specifically it can be the IAB host node-CU-UP) that establishes the F1-U interface with the IAB node, and the upstream destination IP address is the IP address of the IAB host node-CU (or the IAB host node-CU-UP).

[0132] Specifically, if the first IAB node receives the first information from the IAB host node - CU, it indicates that the IAB host node - CU has completed the routing update of the IAB network and obtained the aforementioned first information after the first IAB node's handover. Therefore, by using condition 3), the first IAB node is required to send the second RRC message to the second IAB node before receiving the first information from the IAB host node - CU. This allows the second IAB node to start performing the transport network layer migration as early as possible, avoiding excessively long service interruption delays for the UE due to the second IAB node performing the transport network layer migration too late. This reduces the impact of service delays on UEs serving the IAB access point and improves communication efficiency.

[0133] Typically, the first IAB node receives the F1AP message carrying the first information from the IAB host-CU only after the first IAB node's transport network layer migration is complete. Therefore, the first IAB node generally will not receive the first information before the transport network layer migration is complete.

[0134] As one implementation method, based on the above first condition including conditions 1) and 2), or based on the above first condition including conditions 1), 2) and 3), the above first condition further includes the following condition 4):

[0135] Condition 4): The first IAB node has not completed the transport network layer migration between the first IAB node and the IAB host node -CU according to the first configuration information.

[0136] The fact that the first IAB node did not complete the transport network layer migration between the first IAB node and the IAB host node-CU according to the first configuration information can also be understood as the period before the first IAB node completed the transport network layer migration between the first IAB node and the IAB host node-CU according to the first configuration information.

[0137] By using condition 4), the first IAB node is prevented from sending the second RRC message to the second IAB node only after the first IAB node has completed the transport network layer migration. Therefore, the service interruption delay of the UE caused by the second IAB node performing the transport network layer migration too late can be avoided, thereby reducing the impact of service delay on the UE serving the IAB access point and improving communication efficiency.

[0138] To enable the instruction of subordinate nodes of the migrating IAB node to perform transport network layer migration at an appropriate time, this application provides a communication method, which corresponds to the above-described implementation method one. This method provides a first condition that needs to be met when the subordinate node of the migrating IAB node sends an RRC message to the child node of the subordinate node in the above-described implementation method one.

[0139] This method is applicable to both topology update scenarios within an IAB network host and topology update scenarios across IAB network hosts.

[0140] Referring to Figure 7(b), the method includes the following steps:

[0141] Step 701b: The first IAB node is determined to satisfy the first condition.

[0142] The first IAB node here refers to a subordinate node of the migrated IAB node, for example, it could be... Figure 5 or Figure 6 IAB node 2 or IAB node 3 in the IAB.

[0143] The first condition includes:

[0144] Condition 1): The first IAB node receives the first RRC message from the second IAB node.

[0145] In this context, the second IAB node is the parent node of the first IAB node. For example, refer to... Figure 5 or Figure 6 The first IAB node is IAB node 2, and the second IAB node is IAB node 1, or the first IAB node is IAB node 3, and the second IAB node is IAB node 1.

[0146] The first RRC message includes first configuration information, which is used for transport network layer migration between the first IAB node and the IAB host node - CU. After receiving the first RRC message, the first IAB node can begin performing the transport network layer migration.

[0147] In this case, the first IAB node connects to the IAB host node-CU through different IAB host nodes-DU before and after the handover, as can be seen in the description of the embodiment in Figure 7(a).

[0148] Step 702b: When the first condition is met, the first IAB node sends a second RRC message to the third IAB node. Correspondingly, the second IAB node receives the second RRC message.

[0149] The third IAB node is a child node of the first IAB node. For example, the first IAB node is IAB node 2, the second IAB node is IAB node 1, and the third IAB node is IAB node 4.

[0150] The second RRC message includes second configuration information, which is used for transport network layer migration between the third IAB node and the IAB host node - CU.

[0151] After receiving the second RRC message, the third IAB node can begin performing transport network layer migration.

[0152] According to the above scheme, after receiving the first RRC message from the second IAB node, the first IAB node can start executing the transport network layer migration on the one hand, and immediately send the second RRC message to the child nodes of the first IAB node on the other hand. This can trigger the child nodes of the first IAB node to start executing the transport network layer migration as early as possible, which can avoid the UE's service interruption delay caused by the child nodes of the first IAB node executing the transport network layer migration too late. This reduces the impact of service delay on the UE serving the IAB contact point and can improve communication efficiency.

[0153] As one implementation method, in addition to the first condition including condition 1), the first condition also includes the following condition 2):

[0154] Condition 2): The first IAB node did not receive the first information from the second IAB node.

[0155] The first information is used for data transmission after the first IAB node is switched over. This data transmission can be user plane data transmission or control plane signaling transmission.

[0156] The first information includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration. The meanings of the BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration are as described above.

[0157] Typically, the first IAB node receives the F1AP message carrying the first information from the IAB host-CU only after the first IAB node's transport network layer migration is complete. Therefore, the first IAB node generally will not receive the first information before the transport network layer migration is complete.

[0158] Specifically, if the first IAB node receives the first information from the second IAB node, it indicates that the IAB host node -CU has completed the routing update of the IAB network and obtained the aforementioned first information. Therefore, through condition 2), the first IAB node is required to send the second RRC message to the third IAB node before receiving the first information from the second IAB node. This allows the third IAB node to start performing the transport network layer migration as early as possible, avoiding excessively long service interruption delays for the UE due to the third IAB node performing the transport network layer migration too late. This reduces the impact of service delays on UEs serving the IAB access point and improves communication efficiency.

[0159] As one implementation method, based on the above first condition including conditions 1) and 2), or based on the above first condition including conditions 1), 2) and 3), the above first condition further includes the following condition 4):

[0160] Condition 3): The first IAB node has not completed the transport network layer migration between the first IAB node and the IAB host node -CU according to the first configuration information.

[0161] The fact that the first IAB node did not complete the transport network layer migration between the first IAB node and the IAB host node-CU according to the first configuration information can also be understood as the period before the first IAB node completed the transport network layer migration between the first IAB node and the IAB host node-CU according to the first configuration information.

[0162] By using condition 3), the first IAB node is prevented from sending the second RRC message to the third IAB node only after the first IAB node has completed the transport network layer migration. Therefore, the service interruption delay of the UE caused by the third IAB node performing the transport network layer migration too late can be avoided, thereby reducing the impact of service delay on the UE serving the IAB contact point and improving communication efficiency.

[0163] To enable the instruction of subordinate nodes of the migrating IAB node to perform transport network layer migration at an appropriate time, this application provides a communication method, which corresponds to the above-described implementation method two. This method provides a first condition that needs to be met when the migrating IAB node sends an RRC message to the child node of the migrating IAB node in the above-described implementation method two.

[0164] This method is applicable to both topology update scenarios within an IAB network host and topology update scenarios across IAB network hosts.

[0165] Referring to Figure 8(a), the method includes the following steps:

[0166] Step 801a is the same as step 701a above.

[0167] Step 802a: After the first condition is met, the first IAB node sends indication information to the second IAB node. Correspondingly, the second IAB node receives the indication information.

[0168] The second IAB node is a child node of the first IAB node. Figure 5 or Figure 6 For example, the first IAB node is IAB node 1, and the second IAB node is either IAB node 2 or IAB node 3.

[0169] This indication information is used to trigger the second RRC message in the second IAB node to take effect. This second RRC message includes second configuration information used for transport network layer migration of the second IAB node. The second RRC message can also be referred to as the RRC message of the second IAB node.

[0170] Prior to step 801a, the second IAB node can receive the second RRC message from the IAB host node - CU and store it locally. Then, after receiving the aforementioned indication information from the first IAB node, the second IAB node activates the second RRC message according to that indication information. That is, after receiving the indication information, the second IAB node can begin performing transport network layer migration. Figure 5 or Figure 6 For example, when IAB Node 2 receives the indication information from IAB Node 1 to trigger the RRC message of IAB Node 2 to take effect, it starts to perform transport network layer migration according to the RRC message of IAB Node 2.

[0171] The beneficial effects of the above solution can be referred to the beneficial effects of the embodiment in Figure 7(a) above, and will not be repeated here.

[0172] As one implementation method, in addition to the first condition including the above conditions 1) and 2), it may also include conditions 3) and / or 4) in the embodiment of FIG7(a). For a detailed description, please refer to the description of the embodiment of FIG7(a), which will not be repeated here.

[0173] To enable the subordinate nodes of the migrating IAB node to perform transport network layer migration at an appropriate time, this application provides a communication method corresponding to the above-described implementation method two. This method provides a first condition that needs to be met when the subordinate node of the migrating IAB node sends an RRC message to the child node of the subordinate node in the above-described implementation method two.

[0174] This method is applicable to both topology update scenarios within an IAB network host and topology update scenarios across IAB network hosts.

[0175] Referring to Figure 8(b), the method includes the following steps:

[0176] Step 801b: The first IAB node is determined to satisfy the first condition.

[0177] The first IAB node here refers to a subordinate node of the migrated IAB node, for example, it could be... Figure 5 or Figure 6 IAB node 2 or IAB node 3 in the IAB.

[0178] The first condition includes:

[0179] Condition 1): The first IAB node receives the first instruction information from the second IAB node.

[0180] This first indication information is used to trigger the first RRC message in the first IAB node to take effect.

[0181] In this context, the second IAB node is the parent node of the first IAB node. For example, refer to... Figure 5 or Figure 6 The first IAB node is IAB node 2, and the second IAB node is IAB node 1, or the first IAB node is IAB node 3, and the second IAB node is IAB node 1.

[0182] The meaning of the first RRC message can be found in the description of the embodiment in Figure 7(b).

[0183] Step 802b: When the first condition is met, the first IAB node sends the second indication information to the third IAB node. Correspondingly, the third IAB node receives the second indication information.

[0184] The third IAB node is a child node of the first IAB node. For example, the first IAB node is IAB node 2, the second IAB node is IAB node 1, and the third IAB node is IAB node 4.

[0185] The second instruction message is used to trigger the second RRC message in the third IAB node to take effect.

[0186] The meaning of the second RRC message can be found in the description of the embodiment in Figure 7(b).

[0187] After receiving the second instruction information, the third IAB node begins to perform transport network layer migration based on the stored second RRC message.

[0188] According to the above scheme, after receiving the first indication information from the second IAB node, the first IAB node can start performing the transport network layer migration on the one hand, and immediately send the second indication information to the child nodes of the first IAB node on the other hand. This can trigger the child nodes of the first IAB node to start performing the transport network layer migration as early as possible, which can avoid the UE's service interruption delay caused by the child nodes of the first IAB node performing the transport network layer migration too late. This reduces the impact of service delay on the UE serving the IAB contact point and can improve communication efficiency.

[0189] As one implementation method, in addition to the first condition including the above-mentioned condition 1), it may also include condition 2) and / or condition 3) in the embodiment of FIG7(b). For a detailed description, please refer to the description of the embodiment of FIG7(b), which will not be repeated here.

[0190] It should be noted that in the embodiments shown in Figures 7(a), 7(b), 8(a), and 8(b), the action of the first IAB node "determining that the first condition is met" can be executed or not. When this action is not executed, it can be understood that after the first condition is met, the first IAB node can perform subsequent operations, such as executing steps 702a, 702b, 802a, or 802b.

[0191] It should be noted that the embodiments shown in Figures 7(a), 7(b), 8(a), and 8(b) can be implemented individually or in combination. For example, the embodiments of Figures 7(a) and 7(b) can be implemented in combination, as can the embodiments of Figures 8(a) and 8(b), as well as the embodiments of Figures 7(a) and 8(b), as well as the embodiments of Figures 8(a) and 7(b).

[0192] In scenarios where an IAB node switchover causes the migration of the IAB node and its subordinate nodes to complete transport layer migration, a problem needs to be solved: after the IAB node switchover is completed but before the migration of the IAB node and its subordinate nodes complete the transport layer migration, the source path (i.e., the old transport path) is unavailable, and the transport layer migration on the destination path (i.e., the new transport path) is not yet complete, so the destination path is also temporarily unavailable. In this situation, how to correctly transmit uplink or downlink data packets also needs to be solved.

[0193] To address this issue, this application also provides a corresponding data transmission method. The following data transmission method can be combined with one or more embodiments of the embodiments shown in FIG7(a), FIG7(b), FIG8(a) or FIG8(b), or it can be implemented alone.

[0194] The following data transmission method can be applied to topology update scenarios within an IAB network host or across IAB hosts. When migrating an IAB node from its source parent node to its target parent node, before the migration of the transport network layer between the migrating IAB node and its subordinate IAB nodes and the IAB host node - CU is completed, the IAB nodes on the target path can neither continue using the source path for data transmission nor directly use the target path. In this case, how are data packets transmitted on the target path? The following data transmission method provided in the embodiments of this application can be used.

[0195] For example, refer to Figure 5The IAB node to be migrated is IAB node 1. Before IAB node 1 switches from accessing IAB node 5 to accessing IAB node 6, the source path includes some or all of the following nodes: UE, IAB node 4, IAB node 3, IAB node 1, IAB node 5, IAB host-DU 1, and IAB host node-CU. After IAB node 1 switches from accessing IAB node 5 to accessing IAB node 6, the target path includes some or all of the following nodes: UE, IAB node 4, IAB node 3, IAB node 1, IAB node 6, IAB host-DU 2, and IAB host node-CU. After IAB node 1 switches to accessing IAB node 6, the migration of IAB node and its subordinate IAB nodes on the target path, such as IAB node 3 and IAB node 4, also requires the completion of the transport network layer migration with the IAB host node-CU. Therefore, before the transport network layer migration between IAB node 1, IAB node 3, and IAB node 4 and the IAB host node - CU is completed, neither the source path nor the destination path can be used normally. At this time, the following data transmission method provided in the embodiments of this application can be used.

[0196] The uplink or downlink data packets described in the following embodiments can be service data packets or data packets migrated from the transport network layer. When the uplink or downlink data packet is a data packet migrated from the transport network layer, it can be various data blocks (CHUNK) of the SCTP layer, such as SCTP INITCHUNK, or messages related to the IPsec security negotiation process (such as IKEv2 related messages), or F1AP messages, such as F1 SETUP REQUEST messages and GNB-DU CONFIGURATION UPDATE messages involved in the connection establishment process.

[0197] The following section describes the data transmission methods for migrating IAB nodes and their subordinate nodes in different scenarios.

[0198] I. Data transmission methods for migrating IAB nodes

[0199] The term "first IAB node" will be used below to represent the migrated IAB node. For example, the first IAB node is... Figure 5 or Figure 6 The first IAB node is IAB node 1. Furthermore, before receiving an uplink or downlink data packet, the first IAB node has already received a first RRC message from the IAB host node -CU, which includes first configuration information.

[0200] For uplink transmission, the first configuration information includes a first BAP route identifier, which is used by the first IAB node for uplink data transmission on the target path. This first BAP route identifier can also be referred to as the default BAP route identifier. Optionally, the first configuration information may also include an identifier for the BH RLC CH between the first IAB node and its next-hop node in the uplink transmission. This BH RLC CH identifier identifies the BH RLC CH between the first IAB node and its next-hop node in the uplink transmission, where the next-hop node of the first IAB node can be its target parent node. This BH RLC CH identifier can also be referred to as the default BHRLC CH identifier. Furthermore, the "BH RLC CH between the first IAB node and its next-hop node in the uplink transmission" can also be referred to as the "BH RLC CH between the first IAB node and its parent node."

[0201] For downlink transmission, the first configuration information may also include the identifier of the BHRLC CH between the first IAB node and its child nodes. This BHRLC CH is the default BHRLC CH between the first IAB node and its child nodes. When the first IAB node needs to send a downlink BAP protocol data unit (PDU) to its child node but cannot find a matching mapping relationship based on the current configuration, the first IAB node can map the BAP PDU to this BHRLC CH and send it to the child node. In one possible implementation, the identifier of the BHRLC CH can be jointly determined by the identifier of the child node of the first IAB node (e.g., the BAP address of the child node) and the BHRLC CH ID of the BHRLC CH. The "BHRLC CH between the first IAB node and its child nodes" can also be referred to as the "BHRLC CH between the first IAB node and the next-hop node of the first IAB node in downlink transmission".

[0202] In another possible implementation, the identifier of the BH RLC CH between the first IAB node and its child nodes is not configured through the first configuration information, but is sent to the first IAB node by the IAB host node-CU via an F1AP message. This F1AP message can be sent to the first IAB node before the IAB host node-CU sends the first RRC message to the first IAB node, or it can be sent by the IAB host node-CU to the first IAB node after the first IAB node switches its connection to the target parent node according to the first RRC message. For example, the F1AP message carries configuration information for one or more BH RLC CHs between the first IAB node and one or more of its child nodes, including the identifier of the BH RLC CH between the first IAB node and its child nodes. Optionally, the configuration information may also include indication information to indicate the default BH RLC CH in the configuration information. For example, the first IAB node has two child nodes, namely IAB node a and IAB node b. There are two BH RLC CHs between the first IAB node and IAB node a, namely BH RLC CH a and BH RLC CH b. There are three BH RLC CHs between the first IAB node and IAB node b, namely BH RLC CH c, BH RLC CH d, and BH RLC CH e. The F1AP message sent by the IAB host node -CU to the first IAB node includes configuration information 1 and configuration information 2. Configuration information 1 includes the identifiers of BH RLCCH a and BH RLC CH b between the first IAB node and IAB node a, and also includes indication information to indicate that the BH RLC CH b indicated by the identifier of BH RLC CH b is the default BH RLC CH between the first IAB node and IAB node a. Configuration information 2 includes the identifiers of BH RLC CH c, BH RLC CH d, and BH RLC CH e between the first IAB node and IAB node b, and also includes indication information to indicate that the BH RLC CH c indicated by the identifier of BH RLC CH c is the default BH RLC CH between the first IAB node and IAB node b. In a specific implementation, configuration information 1 and configuration information 2 can be sent to the first IAB node in separate F1AP messages, or configuration information 1 and configuration information 2 can be merged into one configuration information, which can be sent to the first IAB node in one F1AP message.

[0203] Optionally, the first configuration information may also include a new IP address assigned to the first IAB node, which may be used for the transmission of data or signaling by the first IAB node on a new transmission path, such as for the transport network layer migration of the first IAB node.

[0204] The following sections describe the data transmission methods for topology updates within an IAB network host and for cross-host topology updates within an IAB network.

[0205] 1. Data transmission method for migrating IAB nodes in a topology update scenario within the IAB network host.

[0206] In the scenario of migrating IAB nodes within the IAB network host for topology updates, the source and target parent nodes of the migrated IAB nodes are connected to different IAB host nodes (DUs). These different IAB host nodes (DUs) establish F1 interfaces with the same IAB host node (CU). Alternatively, this can be understood as these different IAB host nodes (DUs) belonging to the same IAB host node (CU), or as these different IAB host nodes (DUs) being managed by the same IAB host node (CU). Figure 5 For example, the source parent node of IAB node 1 is connected to the IAB host node -DU 1, the target parent node of IAB node 1 is connected to the IAB host node -DU 2, and the IAB host node -DU 1 and the IAB host node -DU 2 belong to the same IAB host node -CU.

[0207] The following sections are divided into uplink and downlink directions, respectively, to introduce the data transmission methods performed by migrating IAB nodes in the topology update scenario within the IAB network host.

[0208] 1) Upward direction

[0209] refer to Figure 9 This is a flowchart illustrating a data transmission method provided in an embodiment of this application, which describes the processing method after a migrating IAB node receives an uplink data packet.

[0210] The method includes the following steps:

[0211] Step 901: The first IAB node receives the uplink data packet.

[0212] Specifically, the first IAB node receives uplink data packets from its child nodes. These uplink data packets can be generated by the subordinate nodes of the first IAB node, for example... Figure 5 The uplink data packet may be generated by IAB node 2, IAB node 3 or IAB node 4 in the UE, or the uplink data packet may be generated by the UE. This application does not limit the generation method of the uplink data packet.

[0213] The uplink data packet contains a second BAP route identifier, which is added to the uplink data packet by the IAB node that generated the uplink data packet based on the configuration information received from the IAB host node -CU. The second BAP route identifier is used by the IAB node to transmit data on the target path.

[0214] Step 902: When the BAP address in the second BAP route identifier is the same as the BAP address in the first BAP route identifier, the first IAB node sends an uplink data packet according to the first BAP route identifier.

[0215] According to the above scheme, after the migrated IAB node (i.e., the first IAB node) switches to the target parent node, and before the transport network layer migration between the migrated IAB node (i.e., the first IAB node) and the IAB host node - CU is completed, if the BAP address in the received uplink data packet is the same as the BAP address in the first BAP routing identifier, the first IAB node can use the first BAP routing identifier to route the uplink data packet. This ensures successful transmission of received uplink data packets and avoids packet loss. Furthermore, it enables uplink data packet transmission as early as possible, reducing UE service interruption latency.

[0216] As one implementation method, step 902 specifically involves: when the BAP address in the second BAP routing identifier is the same as the BAP address in the first BAP routing identifier, and the first IAB node has not received the first information from the IAB host node -CU, the first IAB node sends uplink data packets according to the first BAP routing identifier. The first information is used for data transmission after the first IAB node switches over, and includes one or more of the following: BAP routing mapping configuration, BH RLC CH mapping configuration, or BAP routing identifier configuration. The specific meanings of BAP routing mapping configuration, BH RLC CH mapping configuration, and BAP routing identifier configuration can be found in the foregoing description. According to this scheme, since the data packets cannot be routed based on the BAP routing configuration information on the target path before receiving the BAP routing configuration information, the method described above can be used to allow the first IAB node to route the received uplink data packets using its own first BAP routing identifier, thereby ensuring successful transmission of the received uplink data packets and avoiding packet loss.

[0217] As one implementation method, the first IAB node sends an uplink data packet based on the first BAP routing identifier. Specifically, the first IAB node determines the next-hop node corresponding to the first BAP routing identifier, and then sends the uplink data packet to the next-hop node. The next-hop node corresponding to the first BAP routing identifier can be the default parent node of the first IAB node, for example, the default parent node can be the target parent node of the first IAB node. Alternatively, the first configuration information may also include an identifier of the next-hop node corresponding to the first BAP routing identifier; in this case, the next-hop node is the node indicated by the identifier of the next-hop node. Optionally, the first configuration information may also include an identifier of the BH RLC CH. This identifier of the BH RLC CH can be used to indicate the default BH RLC CH between the first IAB node and its default parent node. Therefore, the first IAB node can send the uplink data packet to its next-hop node on the BH RLC CH indicated by the identifier of the BH RLC CH.

[0218] refer to Figure 10 This is a flowchart illustrating a data transmission method provided in an embodiment of this application, which describes the method for sending uplink data packets after migrating an IAB node.

[0219] The method includes the following steps:

[0220] Step 1001: The first IAB node generates an uplink data packet.

[0221] The first IAB node here refers to the migrated IAB node, for example, Figure 5 The first IAB node is IAB node 1. Furthermore, before generating the uplink data packet, the first IAB node has received a first RRC message from the IAB host node -CU. This first RRC message includes first configuration information, which includes a first BAP route identifier. This first BAP route identifier is used by the first IAB node to transmit data on the target path.

[0222] The generated uplink data packet contains the first BAP route identifier.

[0223] Step 1002: The first IAB node determines the next-hop node of the first IAB node corresponding to the first BAP route identifier.

[0224] Specifically, the first IAB node determines the next-hop node of the first IAB node corresponding to the first BAP route identifier, which can be referred to as... Figure 9 The descriptions in the embodiments are not repeated here.

[0225] Step 1003: The first IAB node sends an uplink data packet to the next hop node.

[0226] The first IAB node can refer to the following when sending uplink data packets to the next hop node. Figure 9 The descriptions in the embodiments are not repeated here.

[0227] According to the above scheme, after the migrated IAB node switches to the target parent node, and before the transport network layer migration between the migrated IAB node and the IAB host node - CU is completed, the first IAB node generates an uplink data packet and routes the uplink data packet using the first BAP routing identifier. This ensures successful transmission of received uplink data packets and avoids packet loss. Furthermore, it enables uplink data packet transmission as early as possible, reducing UE service interruption latency.

[0228] 2) Downward direction

[0229] refer to Figure 11 This is a flowchart illustrating a data transmission method provided in an embodiment of this application, which describes the processing method after a migrating IAB node receives a downlink data packet.

[0230] The method includes the following steps:

[0231] Step 1101: The first IAB node receives a downlink data packet containing the third BAP route identifier.

[0232] This downlink data packet was generated by the upstream node of the first IAB node, for example, Figure 5 The IAB host node-DU2 in the middle generates the BAP layer header after adding it to the received downlink IP packets.

[0233] In this embodiment, "upstream nodes of the first IAB node" include the parent node of the first IAB node and nodes above the parent node, or can be understood as IAB nodes on the transmission path between the IAB host node and the first IAB node. Specifically, upstream nodes of the first IAB node include the parent node, grandparent node, parent node of the grandparent node, grandparent node of the grandparent node, and so on. This is explained uniformly here and will not be repeated later.

[0234] The downlink data packet contains a third BAP route identifier, which is added to the downlink data packet by the IAB host node-DU node that generated the downlink data packet based on the configuration information received from the IAB host node-CU. The third BAP route identifier is used for downlink data transmission on the target path.

[0235] Step 1102: If the first IAB node determines that it has received the first RRC message and has not received the first information from the IAB host node -CU, then the next-hop node of the first IAB node is determined according to the BAP address in the third BAP routing identifier.

[0236] In other words, when the rerouting trigger condition is met, the first IAB node reroutes according to the BAP address in the third BAP route identifier, and the rerouting node is the next-hop node determined for the first IAB node. The rerouting trigger condition is: the first IAB node confirms that it has received the first RRC message, and the first IAB node has not received the first information from the IAB host node -CU.

[0237] The meaning of the first piece of information here is as described above and will not be repeated here.

[0238] Specifically, the first IAB node determines its next-hop node based on the BAP address in the third BAP route identifier. This can be achieved by: searching its configured routing table for an entry matching the third BAP route identifier; if a match is found, selecting the next-hop node indicated by the next-hop node identifier in that entry; if no match is found, searching for an entry matching the BAP address field in the third BAP route identifier, and then determining the next-hop node indicated by the next-hop node identifier in that entry as the next-hop node for sending downlink data packets. If multiple matching entries (i.e., multiple next-hop node identifiers) are obtained from searching the routing table based on the BAP address field in the third BAP route identifier, the first IAB node can choose any one of the multiple next-hop node identifiers, or select the next-hop node identifier corresponding to the entry with the highest priority among the matching entries.

[0239] Step 1103: The first IAB node sends downlink data packets to the next hop node.

[0240] According to the above scheme, after the migrated IAB node switches to the target parent node, and before the transport network layer migration between the migrated IAB node and the IAB host node - CU is completed, when the first IAB node receives a downlink data packet and determines that the rerouting trigger condition is met, it performs rerouting based on the BAP address in the third BAP routing identifier. This ensures successful transmission of received downlink data packets and avoids packet loss. Furthermore, it enables the transmission of downlink data packets as early as possible, reducing UE service interruption latency.

[0241] 2. Data transmission method for migrating IAB nodes in cross-host topology update scenarios within the IAB network.

[0242] In the scenario of cross-host topology updates in an IAB network, migrating IAB nodes involves the source and target parent nodes connecting to different IAB host nodes (DUs). These different DUs establish F1 interfaces with different IAB host nodes (CUs), which can be understood as either belonging to different IAB host nodes (CUs) or being managed by different IAB host nodes (CUs). Specifically, the source parent node connects to the source IAB host node (DU), which belongs to the source IAB host node (CU). Both the source and target parent nodes are collectively referred to as the source IAB host node. Similarly, the target parent node connects to the target IAB host node (DU), which belongs to the target IAB host node (CU). Both the target and target parent nodes are collectively referred to as the target IAB host node. Figure 6 For example, the source parent node of IAB node 1 is connected to IAB host node - DU 1, and the target parent node of IAB node 1 is connected to IAB host node - DU 2. IAB host node - DU 1 belongs to IAB host node - CU 1, and IAB host node - DU 2 belongs to IAB host node - CU 2. The following describes the data transmission methods performed in the topology update scenario of migrating IAB nodes in the uplink and downlink directions.

[0243] 1) Upward direction

[0244] refer to Figure 12 This is a flowchart illustrating a data transmission method provided in an embodiment of this application, which describes the processing method after a migrating IAB node receives an uplink data packet.

[0245] The method includes the following steps:

[0246] Step 1201: The first IAB node receives the uplink data packet.

[0247] Specifically, the first IAB node receives uplink data packets from its child nodes. These uplink data packets can be generated by the subordinate nodes of the first IAB node, for example... Figure 6 The uplink data packet may be generated by IAB node 2, IAB node 3 or IAB node 4 in the UE, or the uplink data packet may be generated by the UE. This application does not limit the generation method of the uplink data packet.

[0248] The uplink data packet contains a second BAP route identifier, which is added to the uplink data packet by the IAB node that generated the uplink data packet based on the configuration information received from the IAB host node -CU. The second BAP route identifier is used by the IAB node to transmit data on the target path.

[0249] Step 1202: The first IAB node replaces the second BAP route identifier in the uplink data packet with the first BAP route identifier.

[0250] As one implementation method, when the BAP address in the second BAP route identifier is the same as the BAP address allocated by the source IAB host node -CU to the first IAB node, the first IAB node replaces the second BAP route identifier in the uplink data packet with the first BAP route identifier. The BAP address allocated by the source IAB host node -CU to the first IAB node can be sent by the source IAB host node -CU via an RRC message before the first IAB node switches to the target parent node in its MT portion.

[0251] As another implementation method, when the BAP address in the second BAP route identifier is the same as the BAP address allocated by the source IAB host node -CU to the target IAB host node DU, the first IAB node replaces the second BAP route identifier in the uplink data packet with the first BAP route identifier. The BAP address allocated by the source IAB host node -CU to the target IAB host node DU can be pre-configured by the source IAB host node -CU via an F1AP message or an RRC message to the first IAB node, or it can be sent by the target IAB host node -CU to the first IAB node via an RRC message after the MT portion of the first IAB node switches to the target parent node.

[0252] Step 1203: The first IAB node sends an uplink data packet according to the first BAP routing identifier.

[0253] According to the above scheme, after the migrating IAB node switches to the target parent node, and before the transport network layer migration between the migrating IAB node and the IAB host node -CU is completed, when the first IAB node receives an uplink data packet, if the BAP address in the uplink data packet is the same as the BAP address of the first IAB node, or the BAP address in the uplink data packet is the same as the BAP address allocated by the source IAB host node -CU to the target IAB host node -DU, it indicates that the first IAB node needs to replace the BAP routing identifier in the uplink data packet. Then, the first IAB node uses its first BAP routing identifier to route the uplink data packet. In this way, the successful transmission of received uplink data packets can be guaranteed, avoiding packet loss. Furthermore, it can also enable the transmission of uplink data packets as early as possible, reducing the service interruption latency of the UE.

[0254] As one implementation method, step 1202 above can specifically be: when the BAP address in the second BAP routing identifier is the same as the BAP address of the first IAB node, and the first IAB node has not received the first information from the target IAB host node -CU, then the first IAB node sends uplink data packets according to the first BAP routing identifier. Alternatively, step 1202 above can specifically be: when the BAP address in the second BAP routing identifier is the same as the BAP address allocated by the source IAB host node -CU to the target IAB host node -DU, and the first IAB node has not received the first information from the target IAB host node -CU, then the first IAB node sends uplink data packets according to the first BAP routing identifier. The meaning of the first information can be referred to the foregoing description. According to this scheme, since the above data packets cannot be routed according to the BAP routing configuration information on the target path before receiving the BAP routing configuration information (i.e., the first information) on the target path, the above method of this application can be used to allow the first IAB node to route the received uplink data packets using its own first BAP routing identifier, thereby ensuring successful transmission of the received uplink data packets and avoiding packet loss.

[0255] As one implementation method, the first IAB node sends uplink data packets based on the first BAP routing identifier. Specifically, the first IAB node determines the next-hop node corresponding to the first BAP routing identifier, and then sends the uplink data packet to the next-hop node. The next-hop node corresponding to the first BAP routing identifier can be the default parent node of the first IAB node. Alternatively, if the first configuration information also includes an identifier for the next-hop node, then the next-hop node corresponding to the first BAP routing identifier is the node indicated by that identifier. Optionally, the first configuration information also includes an identifier for the BH RLC CH. This identifier can be used to indicate the default BH RLC CH between the first IAB node and its default parent node. Therefore, the first IAB node can send the uplink data packet to its next-hop node on the BH RLC CH indicated by the identifier of the BH RLC CH.

[0256] 2) Downward direction

[0257] refer to Figure 13 This is a flowchart illustrating a data transmission method provided in an embodiment of this application, which describes the processing method after a migrating IAB node receives a downlink data packet.

[0258] The method includes the following steps:

[0259] Step 1301: The first IAB node receives downlink data packets.

[0260] This downlink data packet was generated by the upstream node of the first IAB node, for example, Figure 6 The IAB host node-DU2 in the middle generates the BAP layer header after adding it to the received downlink IP packets.

[0261] The downlink data packet contains a third BAP route identifier, which is added to the downlink data packet by the IAB host node -DU that generated the downlink data packet according to the configuration information received from the target IAB host node -CU. The third BAP route identifier is used for downlink data transmission on the target path.

[0262] As one implementation method, the BAP address in the third BAP route identifier is the BAP address of the first IAB node on the destination path; that is, the BAP address in the third BAP route identifier is the BAP address assigned to the first IAB node by the destination IAB host-CU. For example, refer to... Figure 6 The BAP address in the third BAP route identifier is the BAP address assigned by IAB host node 2-CU to IAB node 1.

[0263] As another implementation method, the BAP address in the third BAP route identifier is the BAP address assigned by the target IAB host-CU to the subordinate nodes of the first IAB node. Furthermore, the first IAB node can obtain the BAP address assigned by the target IAB host-CU to its subordinate nodes from either the source IAB host-CU or the target IAB host-CU beforehand. For example, refer to... Figure 6 The BAP address in the third BAP route identifier is the BAP address assigned by IAB host node 2-CU to IAB node 6.

[0264] Step 1302: The first IAB node replaces the third BAP route identifier in the downlink data packet with the fourth BAP route identifier.

[0265] The BAP address in this fourth BAP route identifier is the BAP address assigned by the source IAB host node -CU to the subordinate nodes of the first IAB node. For example, refer to... Figure 6 The BAP address in the fourth BAP route identifier is the BAP address assigned by IAB host node 1-CU to IAB node 6.

[0266] As one implementation method, the first configuration information in the first RRC message received by the first IAB node also includes the fourth BAP route identifier. Optionally, the fourth BAP route identifier in the first configuration information corresponds to the aforementioned third BAP route identifier.

[0267] As an alternative implementation of step 1302, the first IAB node may also retain the third BAP route identifier and then add a fourth BAP route identifier to the header of the downlink data packet.

[0268] Step 1303: The first IAB node confirms that it has received the first RRC message, and the first IAB node has not received the first information from the IAB host node-CU (i.e., the target IAB host node-CU). Based on the BAP address in the fourth BAP routing identifier, the next hop node of the first IAB node is determined.

[0269] In other words, when the rerouting trigger condition is met, the first IAB node reroutes according to the BAP address in the fourth BAP route identifier, and the rerouting node is the next-hop node determined for the first IAB node. The rerouting trigger condition is: the first IAB node confirms that it has received the first RRC message, and the first IAB node has not received the first information from the IAB host node -CU.

[0270] The meaning of the first piece of information here is as described above and will not be repeated here.

[0271] Step 1304: The first IAB node sends downlink data packets to the next hop node.

[0272] According to the above scheme, after the migrated IAB node switches to the target parent node, and before the migration of the transport network layer between the migrated IAB node and its subordinate IAB nodes on the target path and the IAB host node - CU is completed, when the first IAB node receives a downlink data packet, if it determines that the rerouting trigger condition is met, it will reroute according to the BAP address in the fourth BAP route identifier. This ensures the successful transmission of received downlink data packets and avoids packet loss.

[0273] II. Data transmission method for migrating subordinate IAB nodes of an IAB node

[0274] The first IAB node is used below to represent the subordinate node of the migrated IAB node. For example, the first IAB node is... Figure 5 or Figure 6 The IAB nodes are 2 and 3. Furthermore, before receiving the uplink or downlink data packet, the first IAB node has already received a first RRC message from its parent node (hereinafter referred to as the second IAB node) or the IAB host node -CU. This first RRC message includes first configuration information.

[0275] The information carried in this first configuration information is similar to the information carried in the first configuration information received by the migrated IAB node, as described above. Please refer to the preceding description.

[0276] Whether it's a topology update scenario within an IAB network host or a cross-host topology update scenario, the method by which subordinate nodes of a migrated IAB node handle received uplink data packets in the uplink direction is the same as described above. Figure 9 In the embodiments, the method for migrating IAB nodes to process received uplink data packets is similar and will not be described again.

[0277] Whether it's a topology update scenario within an IAB network host or a cross-host topology update scenario, the method by which subordinate nodes of a migrated IAB node handle their generated uplink data packets in the uplink direction is the same as described above. Figure 10 In the embodiments, the method for migrating IAB nodes to process their own generated uplink data packets is similar and will not be described again.

[0278] Whether it's a topology update scenario within an IAB network host or a cross-host topology update scenario, the method by which subordinate nodes of a migrated IAB node handle received downlink data packets in the uplink direction is the same as described above. Figure 11 In the embodiments, the method for migrating IAB nodes to process received downlink data packets is similar and will not be described again.

[0279] It is understood that, in order to achieve the functions in the above embodiments, migrating an IAB node or its subordinate nodes includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, based on the units and method steps of the various examples described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0280] Figure 14 and Figure 15 The diagram illustrates the possible communication devices provided in the embodiments of this application. These communication devices can be used to implement the functions of migrating IAB nodes or subordinate nodes of IAB nodes in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments. In the embodiments of this application, the communication device can be the migrating IAB node or subordinate node of the migrating IAB node in the embodiments of this application, or it can be a module (such as a chip) applied to migrating IAB nodes, or a module (such as a chip) applied to migrating subordinate nodes of IAB nodes.

[0281] like Figure 14 As shown, the communication device 1400 includes a processing unit 1410 and a transceiver unit 1420. The communication device 1400 is used to implement the function of migrating an IAB node or migrating a subordinate node of an IAB node in the above method embodiments.

[0282] In the first embodiment, when the communication device 1400 is used to implement the function of migrating IAB nodes in the above method embodiment: the processing unit 1410 is used to determine that a first condition is met, the first condition including: the first IAB node receives a first RRC message from the IAB host CU, and the first IAB node switches from its source parent node to its target parent node according to the first RRC message. The transceiver unit 1420 is used to send indication information to the second IAB node when the first condition is met, the indication information being used to trigger the second RRC message in the second IAB node to take effect. Alternatively, when the first condition is met, the first IAB node sends the second RRC message to the second IAB node. The first RRC message includes first configuration information used for transport network layer migration between the first IAB node and the IAB host CU, and the second RRC message includes second configuration information used for transport network layer migration between the second IAB node and the IAB host CU. The second IAB node is a child node of the first IAB node. The source parent node and the target parent node are connected to different IAB host DUs. The first IAB node is connected to the IAB host CU through the different IAB host DUs before and after the switch.

[0283] As one possible implementation, the first condition further includes: the first IAB node has not received first information from the IAB host CU, the first information being used for data transmission after the first IAB node is switched, the first information including one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0284] As one possible implementation, the first condition further includes: the first IAB node has not completed the transport network layer migration between the first IAB node and the IAB host CU according to the first configuration information.

[0285] As one possible implementation, the source parent node and the target parent node are connected to different IAB host DUs, all belonging to the IAB host CU. The first configuration information includes a first BAP route identifier. The transceiver unit 1420 is configured to receive uplink data packets containing a second BAP route identifier, and to send the uplink data packet according to the first BAP route identifier when the BAP address in the second BAP route identifier is the same as the BAP address in the first BAP route identifier.

[0286] As one possible implementation, the transceiver unit 1420 is configured to send the uplink data packet according to the first BAP route identifier when the BAP address in the second BAP route identifier is the same as the BAP address in the first BAP route identifier, and no first information has been received from the IAB host CU. The first information is used for data transmission after the first IAB node switchover, and the first information includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0287] As one possible implementation, the source parent node connects to an IAB host DU belonging to that IAB host CU, and the target parent node connects to an IAB host DU belonging to another IAB host CU different from that IAB host CU. The first configuration information includes a first BAP routing identifier. Transceiver unit 1420 is configured to receive uplink data packets containing a second BAP routing identifier. Processing unit 1410 is configured to replace the second BAP routing identifier in the downlink data packet with the first BAP routing identifier when the BAP address in the second BAP routing identifier is the same as the BAP address allocated by the IAB host CU to the first IAB node. Transceiver unit 1420 is configured to send the uplink data packet according to the first BAP routing identifier.

[0288] As one possible implementation, the transceiver unit 1420 is configured to, when the BAP address in the second BAP route identifier is the same as the BAP address of the first IAB node, and no first information has been received from the IAB host CU, send the uplink data packet according to the first BAP route identifier. The first information is used for data transmission after the first IAB node switches over, and the first information includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0289] As one possible implementation, the first configuration information also includes the identifier of the BH RLC CH. Processing unit 1410 is used to determine the next-hop node of the first IAB node corresponding to the first BAP route identifier. Transceiver unit 1420 is used to send the uplink data packet to the next-hop node on the BH RLC CH.

[0290] As one possible implementation, the next-hop node is the default parent node of the first IAB node. Alternatively, the first configuration information may also include the identifier of the next-hop node.

[0291] As one possible implementation, the source parent node and the target parent node are connected to different IAB host DUs, all belonging to the IAB host CU. The transceiver unit 1420 receives downlink data packets containing a third BAP route identifier. The processing unit 1410 determines that the first RRC message has been received and that the first IAB node has not received the first information from the IAB host CU, and determines the next-hop node of the first IAB node based on the BAP address in the third BAP route identifier. The transceiver unit 1420 sends the downlink data packet to the next-hop node. The first information is used for data transmission after the first IAB node switches, and includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0292] As one possible implementation, the source parent node connects to an IAB host DU belonging to that IAB host CU, and the target parent node connects to an IAB host DU belonging to another IAB host CU different from that IAB host CU. The first configuration information includes a fourth BAP routing identifier. Transceiver unit 1420 is used to receive downlink data packets containing a third BAP routing identifier, where the BAP address in the third BAP routing identifier is the BAP address of the first IAB node. Processing unit 1410 is used to replace the third BAP routing identifier in the downlink data packet with the fourth BAP routing identifier. The first IAB node determines that it has received the first RRC message and has not received the first information from the IAB host CU. Based on the BAP address in the fourth BAP routing identifier, it determines the next-hop node of the first IAB node. Transceiver unit 1420 is used to send the downlink data packet to the next-hop node. The first information is used for data transmission after the first IAB node is switched, and the first information includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0293] As one possible implementation, the first configuration information includes a new IP address assigned to the first IAB node.

[0294] As one possible implementation, the first configuration information includes a first BAP route identifier. Processing unit 1410 is used to determine the next-hop node of the first IAB node corresponding to the first BAP route identifier. Transceiver unit 1420 is used to send an uplink data packet to the next-hop node, the uplink data packet containing the first BAP route identifier.

[0295] In the second embodiment, when the communication device 1400 is used to implement the function of migrating subordinate nodes of the IAB node in the above method embodiment: the processing unit 1410 is used to determine that a first condition is met, the first condition including: the first IAB node receives a first indication information or a first RRC message from a second IAB node, the second IAB node being the parent node of the first IAB node, and the first indication information being used to trigger the first RRC message in the first IAB node to take effect. The transceiver unit 1420 is used to send a second indication information to a third IAB node when the first condition is met, the second indication information being used to trigger the second RRC message in the third IAB node to take effect. Alternatively, the transceiver unit 1420 is used to send the second RRC message to the third IAB node when the first condition is met, the third IAB node being a child node of the first IAB node. The first RRC message includes first configuration information, which is used for the transport network layer migration between the first IAB node and the IAB host CU. The second RRC message includes second configuration information, which is used for the transport network layer migration between the third IAB node and the IAB host CU. The first IAB node connects to the IAB host CU through different IAB host DUs before and after the transport network layer migration.

[0296] As one possible implementation, the first condition further includes: the first IAB node did not receive first information from the second IAB node, the first information being used for data transmission of the first IAB node after migration at the transport network layer, the first information including one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0297] As one possible implementation, the first condition further includes: the first IAB node has not completed the transport network layer migration between the first IAB node and the IAB host CU according to the first configuration information.

[0298] As one possible implementation, the first configuration information includes a first BAP route identifier. The transceiver unit 1420 is configured to receive an uplink data packet containing a second BAP route identifier, and, when the BAP address in the second BAP route identifier is the same as the BAP address in the first BAP route identifier, send the uplink data packet according to the first BAP route identifier.

[0299] As one possible implementation, when the BAP address in the second BAP route identifier is the same as the BAP address in the first BAP route identifier, and the first IAB node has not received the first information from the second IAB node, the transceiver unit 1420 is used to send the uplink data packet according to the first BAP route identifier. The first information is used for data transmission after the first IAB node switchover, and the first information includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0300] As one possible implementation, the first configuration information also includes the identifier of the BH RLC CH. Processing unit 1410 is used to determine the next-hop node of the first IAB node corresponding to the first BAP route identifier. Transceiver unit 1420 is used to send the uplink data packet to the next-hop node on the BH RLC CH.

[0301] As one possible implementation, the next-hop node is the default parent node of the first IAB node. Alternatively, the first configuration information may also include the identifier of the next-hop node.

[0302] As one possible implementation, the transceiver unit 1420 is used to receive downlink data packets containing a third BAP route identifier. The processing unit 1410 is used to determine that the first RRC message has been received and that the first IAB node has not received the first information from the IAB host CU, and to determine the next-hop node of the first IAB node based on the BAP address in the third BAP route identifier. The transceiver unit 1420 is used to send the downlink data packet to the next-hop node. The first information is used for data transmission after the first IAB node handover, and the first information includes one or more of the following: BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

[0303] As one possible implementation, the first configuration information includes a new IP address assigned to the first IAB node.

[0304] For a more detailed description of the processing unit 1410 and the transceiver unit 1420, please refer directly to the relevant descriptions in the foregoing method embodiments; they will not be repeated here.

[0305] like Figure 15As shown, the communication device 1500 includes a processor 1510 and an interface circuit 1520. The processor 1510 and the interface circuit 1520 are coupled to each other. It is understood that the interface circuit 1520 can be a transceiver or an input / output interface. Optionally, the communication device 1500 may also include a memory 1530 for storing instructions executed by the processor 1510, or storing input data required by the processor 1510 to execute instructions, or storing data generated after the processor 1510 executes instructions.

[0306] When the communication device 1500 is used to implement the aforementioned method embodiment, the processor 1510 is used to implement the functions of the processing unit 1410, and the interface circuit 1520 is used to implement the functions of the transceiver unit 1420.

[0307] When the aforementioned communication device is a module applied to an IAB node, the module implements the functions of the IAB node in the above method embodiments. This module receives information from other modules (such as radio frequency modules or antennas) within the IAB node, information sent to the IAB node by a terminal or other IAB nodes; or, the module sends information to other modules (such as radio frequency modules or antennas) within the IAB node, information sent by the IAB node to a terminal or other IAB nodes. The module here can be the baseband chip of the IAB node, or it can be a CU, DU, or other modules.

[0308] It is understood that the processor in the embodiments of this application may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor may be a microprocessor or any conventional processor.

[0309] The method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, compact disc read-only memory (CD-ROM), or any other form of storage medium well known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Furthermore, the ASIC can reside in a migrated IAB node or a subordinate node of a migrated IAB node. Alternatively, the processor and storage medium can exist as discrete components in a migrated IAB node or a subordinate node of a migrated IAB node.

[0310] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a base station, a terminal, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0311] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0312] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates an "or" relationship between the preceding and following related objects; in the formulas of this application, the character " / " indicates a "division" relationship between the preceding and following related objects.

[0313] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

Claims

1. A communication method, characterized in that, include: The first access backhaul integrated IAB node is determined to meet a first condition, the first condition including: the first IAB node receives a first radio resource control (RRC) message from the IAB host centralized unit (CU); the first IAB node switches from its source parent node to its target parent node according to the first RRC message; and the first IAB node does not receive first information from the IAB host CU. The first information is used for data transmission after the first IAB node switches. The first information includes one or more of the following: Backhaul Adaptation Protocol (BAP) route mapping configuration, Backhaul Radio Link Control Channel (BH RLC CH) mapping configuration, or BAP route identifier configuration. When the first condition is met, the first IAB node sends an indication message to the second IAB node, the indication message being used to trigger the second RRC message in the second IAB node to take effect; or, when the first condition is met, the first IAB node sends the second RRC message to the second IAB node. The first RRC message includes first configuration information, which is used for transport network layer migration between the first IAB node and the IAB host CU. The second RRC message includes second configuration information, which is used for transport network layer migration between the second IAB node and the IAB host CU. The second IAB node is a child node of the first IAB node. The source parent node and the target parent node are connected to different IAB host distributed units (DUs). The first IAB node is connected to the IAB host CU through the different IAB host DUs before and after the handover.

2. The method as described in claim 1, characterized in that, The first condition also includes: The first IAB node did not complete the transport network layer migration between the first IAB node and the IAB host CU according to the first configuration information.

3. The method as described in claim 1, characterized in that, The different IAB host DUs connected to the source parent node and the target parent node all belong to the IAB host CU, and the first configuration information includes the first BAP route identifier; The method further includes: The first IAB node receives an uplink data packet, which contains a second BAP route identifier; When the BAP address in the second BAP routing identifier is the same as the BAP address in the first BAP routing identifier, the first IAB node sends the uplink data packet according to the first BAP routing identifier.

4. The method as described in claim 3, characterized in that, When the BAP address in the second BAP route identifier is the same as the BAP address in the first BAP route identifier, the first IAB node sends the uplink data packet according to the first BAP route identifier, including: When the BAP address in the second BAP route identifier is the same as the BAP address in the first BAP route identifier, and the first IAB node has not received the first information from the IAB host CU, the first IAB node sends the uplink data packet according to the first BAP route identifier.

5. The method as described in claim 1, characterized in that, The source parent node connects to the IAB host DU which belongs to the IAB host CU, and the target parent node connects to the IAB host DU which belongs to another IAB host CU that is different from the IAB host CU. The first configuration information includes the first BAP route identifier. The method further includes: The first IAB node receives an uplink data packet, which contains a second BAP route identifier; When the BAP address in the second BAP route identifier is the same as the BAP address allocated by the IAB host CU to the first IAB node, the first IAB node replaces the second BAP route identifier in the uplink data packet with the first BAP route identifier. The first IAB node sends the uplink data packet according to the first BAP routing identifier.

6. The method as described in claim 5, characterized in that, When the BAP address in the second BAP route identifier is the same as the BAP address of the first IAB node, the first IAB node sends the uplink data packet according to the first BAP route identifier, including: When the BAP address in the second BAP route identifier is the same as the BAP address of the first IAB node, and the first IAB node has not received the first information from the IAB host CU, the first IAB node sends the uplink data packet according to the first BAP route identifier.

7. The method according to any one of claims 3 to 6, characterized in that, The first configuration information also includes the identifier of BHRLC CH; The first IAB node sends the uplink data packet according to the first BAP route identifier, including: The first IAB node determines the next-hop node of the first IAB node corresponding to the first BAP route identifier; The first IAB node sends the uplink data packet to the next-hop node on the BH RLC CH.

8. The method as described in claim 7, characterized in that, The next-hop node is the default parent node of the first IAB node; or, The first configuration information also includes the identifier of the next-hop node.

9. The method as described in claim 1, characterized in that, The different IAB host DUs connected to the source parent node and the target parent node all belong to the IAB host CU, and the method further includes: The first IAB node receives downlink data packets, which contain a third BAP routing identifier; The first IAB node determines that it has received the first RRC message and that it has not received the first information from the IAB host CU. Based on the BAP address in the third BAP route identifier, the next hop node of the first IAB node is determined. The first IAB node sends the downlink data packet to the next-hop node.

10. The method as described in claim 1, characterized in that, The source parent node connects to the IAB host DU which belongs to the IAB host CU, and the target parent node connects to the IAB host DU which belongs to another IAB host CU that is different from the IAB host CU. The first configuration information includes the fourth BAP route identifier. The method further includes: The first IAB node receives a downlink data packet, which contains a third BAP route identifier, and the BAP address in the third BAP route identifier is the BAP address of the first IAB node. The first IAB node replaces the third BAP route identifier in the downlink data packet with the fourth BAP route identifier; The first IAB node determines that it has received the first RRC message and that it has not received the first information from the IAB host CU. Based on the BAP address in the fourth BAP routing identifier, the next hop node of the first IAB node is determined. The first IAB node sends the downlink data packet to the next-hop node.

11. The method according to any one of claims 1 to 6, 8 to 10, characterized in that, The first configuration information includes a new Internet Protocol (IP) address assigned to the first IAB node.

12. The method as described in claim 7, characterized in that, The first configuration information includes a new Internet Protocol (IP) address assigned to the first IAB node.

13. A communication method, characterized in that, include: The first access backhaul integrated IAB node determines that it meets the first condition, which includes: the first IAB node receives a first indication information or a first radio resource control (RRC) message from the second IAB node, and the first IAB node does not receive first information from the second IAB node. The second IAB node is the parent node of the first IAB node. The first indication information is used to trigger the first RRC message in the first IAB node to take effect. The first information is used for data transmission of the first IAB node after migration at the transport network layer. The first information includes one or more of the following: Backhaul Adaptation Protocol (BAP) route mapping configuration, Backhaul Radio Link Control Channel (BH) RLC CH mapping configuration, or BAP route identifier configuration. When the first condition is met, the first IAB node sends a second indication message to the third IAB node, the second indication message being used to trigger the second RRC message in the third IAB node to take effect; or, when the first condition is met, the first IAB node sends the second RRC message to the third IAB node, the third IAB node being a child node of the first IAB node. The first RRC message includes first configuration information, which is used for the transport network layer migration between the first IAB node and the IAB host centralized unit (CU). The second RRC message includes second configuration information, which is used for the transport network layer migration between the third IAB node and the IAB host CU. The first IAB node connects to the IAB host CU through different IAB host distributed units (DUs) before and after the transport network layer migration.

14. The method as described in claim 13, characterized in that, The first condition also includes: The first IAB node did not complete the transport network layer migration between the first IAB node and the IAB host CU according to the first configuration information.

15. The method as described in claim 13, characterized in that, The first configuration information includes the first BAP route identifier; The method further includes: The first IAB node receives an uplink data packet, which contains a second BAP route identifier; When the BAP address in the second BAP routing identifier is the same as the BAP address in the first BAP routing identifier, the first IAB node sends the uplink data packet according to the first BAP routing identifier.

16. The method as described in claim 15, characterized in that, When the BAP address in the second BAP route identifier is the same as the BAP address in the first BAP route identifier, the first IAB node sends the uplink data packet according to the first BAP route identifier, including: When the BAP address in the second BAP routing identifier is the same as the BAP address in the first BAP routing identifier, and the first IAB node has not received the first information from the second IAB node, the first IAB node sends the uplink data packet according to the first BAP routing identifier.

17. The method as described in claim 15 or 16, characterized in that, The first configuration information also includes the identifier of BH RLC CH; The first IAB node sends the uplink data packet according to the first BAP route identifier, including: The first IAB node determines the next-hop node of the first IAB node corresponding to the first BAP route identifier; The first IAB node sends the uplink data packet to the next-hop node on the BH RLC CH.

18. The method as described in claim 17, characterized in that, The next-hop node is the default parent node of the first IAB node; or, The first configuration information also includes the identifier of the next-hop node.

19. The method as described in claim 13, characterized in that, The method further includes: The first IAB node receives downlink data packets, which contain a third BAP routing identifier; The first IAB node determines that it has received the first RRC message and that it has not received the first information from the IAB host CU. Based on the BAP address in the third BAP route identifier, the next hop node of the first IAB node is determined. The first IAB node sends the downlink data packet to the next-hop node.

20. The method according to any one of claims 13 to 16, 18 to 19, characterized in that, The first configuration information includes a new Internet Protocol (IP) address assigned to the first IAB node.

21. The method as described in claim 17, characterized in that, The first configuration information includes a new Internet Protocol (IP) address assigned to the first IAB node.

22. A communication device, characterized in that, It includes modules for performing the method as described in any one of claims 1 to 12, or modules for performing the method as described in any one of claims 13 to 21.

23. A communication device, characterized in that, The device includes a processor and an interface circuit. The interface circuit is used to receive signals from other communication devices besides the communication device and transmit them to the processor, or to send signals from the processor to other communication devices besides the communication device. The processor is used to implement the method as described in any one of claims 1 to 12, or to implement the method as described in any one of claims 13 to 21, through logic circuits or execution code instructions.

24. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions, which, when executed by a communication device, implement the method as described in any one of claims 1 to 21.

25. A computer program product, characterized in that, The computer program product includes a computer program or instructions that, when executed by a communication device, implement the method as described in any one of claims 1 to 21.

26. A chip system, characterized in that, include: A processor for performing the method according to any one of claims 1 to 21.

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