CN115707029A

CN115707029A - Communication method and communication device

Info

Publication number: CN115707029A
Application number: CN202110902631.2A
Authority: CN
Inventors: 朱元萍; 曹振臻; 史玉龙; 孙飞
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-08-06
Filing date: 2021-08-06
Publication date: 2023-02-17
Also published as: WO2023011621A1

Abstract

The application provides a communication method and a communication device. The method comprises the following steps: after the first IAB node receives the first RRC message from the IAB host CU and the first IAB node switches from the source parent node of the first IAB node to the target parent node of the first IAB node according to the first RRC message, the first IAB node sends the 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, so that it is avoided that the second IAB node starts to perform transport network layer migration before the first IAB node successfully switches to access to the target parent node of the first IAB node, and therefore it is avoided that the second IAB node performs transport network layer migration too early to cause migration failure, thereby reducing the service delay impact on the terminal serving the IAB node, and improving communication efficiency.

Description

Communication method and communication device

Technical Field

The present application relates to the field of communications technologies, and in particular, to a communication method and a communication apparatus.

Background

Currently, in an Integrated Access and Backhaul (IAB) network, topology update of the IAB network is allowed, for example, an IAB node is switched from a source parent node to a target parent node, and after the switching, transport Network Layer (TNL) migration (migration) of the IAB node and a node subordinate to the IAB node is further completed, so that the topology update is completed. Wherein, the subordinate node of the IAB node is also an IAB node, and includes a child node, a grandchild node, and the like of the IAB node.

However, there is no good method at present when the subordinate node of the IAB node is triggered to perform transport network layer migration to reduce the service delay impact on the terminal served by the IAB node.

Disclosure of Invention

The application provides a communication method and a communication device, which are used for triggering an IAB node to execute transport network layer migration at a proper time so as to reduce the service delay influence on a terminal served by the IAB node and further improve the communication efficiency.

In a first aspect, the present embodiments provide a communication method, which may be performed by a first IAB node or a module (e.g., a chip) applied in the first IAB node, where the first IAB node is a migration IAB node. Taking the first IAB node as an example to execute the method, the first IAB node determines that a first condition is satisfied, the first condition comprising: the first IAB node receives a first RRC message from an IAB host 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. When the first condition is satisfied, the first IAB node sends indication information to the second IAB node, where the indication information is used to trigger a second RRC message in the second IAB node to take effect. Alternatively, the first IAB node sends the second RRC message to the second IAB node when the first condition is satisfied. Wherein the first RRC message includes first configuration information for transport network layer migration between the first IAB node and the IAB anchor CU, and the second RRC message includes second configuration information for transport network layer migration between the second IAB node and the IAB anchor 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, and the first IAB node is connected to the IAB host CU through the different IAB host DUs before and after handover.

According to the above scheme, after receiving the first RRC message from the IAB host CU and the first IAB node is switched from the source parent node of the first IAB node to the target parent node of the first IAB node according to the first RRC message, the first IAB node sends the 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, so that it is avoided that the second IAB node starts to perform transport network layer migration before the first IAB node is successfully switched to the target parent node of the first IAB node, and therefore it is avoided that the second IAB node fails to perform transport network layer migration too early, thereby reducing the traffic delay impact on the terminal serving the IAB node, and improving communication efficiency.

As a possible implementation method, the first condition further includes: the first IAB node does not receive first information from the IAB anchor CU, the first information being used for data transmission after handover of the first IAB node, the first information comprising one or more of a BAP route mapping configuration, a BH RLC CH mapping configuration, or a BAP route identification configuration.

According to the above scheme, the first IAB node is limited to send the second RRC message to the second IAB node before receiving the first information from the IAB host node-CU, so that the second IAB node can start to perform transport network layer migration as early as possible, thereby reducing the influence of the service delay on the terminal served by the IAB node, and improving the communication efficiency.

As a possible implementation method, the first condition further includes: the first IAB node does not complete transport network layer migration between the first IAB node and the IAB host CU according to the first configuration information.

According to the scheme, the first IAB node is prevented from starting to send the second RRC message to the second IAB node after the transport network layer migration is completed, so that the problem that the service interruption time delay of the terminal is too long due to the fact that the transport network layer migration is executed too late by the second IAB node can be avoided.

As a possible implementation method, the different IAB host DUs connected to the source father node and the target father node all belong to the IAB host CU, and the first configuration information includes a first BAP route identifier. And the first IAB node receives an uplink data packet, wherein the uplink data packet comprises a second BAP routing identifier. And 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.

According to the above solution, after the migration IAB node is switched to the target parent node and before the transport network layer migration between the migration IAB node and the IAB host node-CU is completed, the first IAB node may use the first BAP routing identifier to route the uplink data packet if the BAP address in the uplink data packet is the same as the BAP address in the first BAP routing identifier after the first IAB node receives the uplink data packet. Therefore, the received uplink data packet can be successfully sent, and the packet loss is avoided. And the transmission of the uplink data packet can be realized as early as possible, and the service interruption time delay of the terminal is reduced.

As a possible implementation method, 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 does not receive the first information from the IAB host CU, the first IAB node sends the uplink data packet according to the first BAP routing identifier. The first information is used for data transmission after the first IAB node is switched, and the first information includes one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

According to the scheme, before the BAP routing configuration information is received on the target path, the routing of the data packet can not be performed according to the BAP routing configuration information on the target path, but the method can be used, and the first IAB node uses the first BAP routing identifier of the first IAB node to route the received uplink data packet, so that the received uplink data packet can be ensured to be successfully sent, and the occurrence of packet loss is avoided. As a possible implementation method, the IAB host DU connected to the source father node belongs to the IAB host CU, the IAB host DU connected to the target father node belongs to another IAB host CU different from the IAB host CU, and the first configuration information includes a first BAP route identifier. And the first IAB node receives an uplink data packet, wherein the uplink data packet comprises a second BAP routing identifier. And when the BAP address in the second BAP route identifier is the same as the BAP address distributed by the IAB host CU to the first IAB node, the first IAB node replaces the second BAP route identifier in the downlink data packet with the first BAP route identifier. And the first IAB node sends the uplink data packet according to the first BAP routing identification.

According to the above scheme, after the migration IAB node is switched to the target parent node and before the transport network layer between the migration IAB node and the IAB host node-CU is migrated, the first IAB node receives the uplink data packet, and 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, so that the first IAB node routes the uplink data packet by using the first BAP routing identifier of the first IAB node. Therefore, the received uplink data packet can be ensured to be successfully sent, and the packet loss is avoided. And, can also realize the transmission of the upstream data packet as early as possible, reduce the service interruption time delay of the terminal station.

As a possible implementation method, 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 does not receive the first information from the IAB host CU, the first IAB node sends the uplink data packet according to the first BAP routing identifier. The first information is used for data transmission after the first IAB node is switched, and the first information includes one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

According to the scheme, before the BAP routing configuration information is received on the target path, the routing of the data packet can not be performed according to the BAP routing configuration information on the target path, but the method can be used, and the first IAB node uses the first BAP routing identifier of the first IAB node to route the received uplink data packet, so that the successful sending of the received uplink data packet can be ensured, and the occurrence of packet loss is avoided.

As a possible implementation method, the first configuration information further includes an identifier of the BH RLC CH. The first IAB node determines a next hop node of the first IAB node corresponding to the first BAP route identifier. The first IAB node sends the uplink packet to the next hop node on the BH RLC CH.

As a possible implementation, the next hop node is the default parent node of the first IAB node. Or, the first configuration information further includes an identifier of the next hop node.

As a possible implementation method, different IAB host DUs connected to the source father node and the target father node all belong to the IAB host CU, and the first IAB node receives a downlink data packet, where the downlink data packet includes a third BAP route identifier. And the first IAB node determines that the first RRC message is received and the first IAB node does not receive the first information from the IAB host CU, and determines a next hop node of the first IAB node according to the BAP address in the third BAP routing identifier. 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 is switched, and the first information includes one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

According to the scheme, after the migration IAB node is switched to the target father node and before the transfer network layer between the migration IAB node and the IAB host node-CU is migrated, the first IAB node receives the downlink data packet and performs rerouting according to the BAP address in the third BAP routing identifier when the rerouting triggering condition is determined to be met. Therefore, the received downlink data packet can be ensured to be successfully sent, and the packet loss is avoided. And, can also realize the transmission of the downstream data packet as early as possible, reduce the service interruption time delay of the terminal station.

As a possible implementation method, the IAB host DU connected to the source parent node belongs to the IAB host CU, the IAB host DU connected to the target parent node belongs to another IAB host CU different from the IAB host CU, and the first configuration information includes the fourth BAP route identifier. The first IAB node receives a downlink data packet, where the downlink data packet includes a third BAP routing identifier, and a BAP address in the third BAP routing identifier is a 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. And the first IAB node determines that the first RRC message is received and the first IAB node does not receive the first information from the IAB host CU, and determines a next hop node of the first IAB node according to the BAP address in the fourth BAP routing identifier. 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 is switched, and the first information includes one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

According to the scheme, after the migration IAB node is switched to the target father node and before the transport network layer between the migration IAB node and the IAB host node-CU is migrated, the first IAB node receives the downlink data packet and performs rerouting according to the BAP address in the fourth BAP routing identifier when the rerouting triggering condition is determined to be met. Therefore, the received downlink data packet can be ensured to be successfully sent, and the packet loss is avoided. And, can also realize the transmission of the downstream data packet as early as possible, reduce the service interruption time delay of the terminal station.

As a possible implementation method, the first configuration information includes a new IP address allocated for the first IAB node.

As a possible implementation method, the first configuration information includes a first BAP routing identifier. The first IAB node determines a next hop node of the first IAB node corresponding to the first BAP routing identifier. And the first IAB node sends an uplink data packet to the next hop node, wherein the uplink data packet comprises the first BAP routing identifier.

According to the scheme, after the migration IAB node is switched to the target father node and before the migration of the transmission network layer between the migration IAB node and the IAB host node-CU is completed, the first IAB node generates an uplink data packet and then uses the first BAP routing identifier to route the uplink data packet. Therefore, the received uplink data packet can be successfully sent, and the packet loss is avoided. And the transmission of the uplink data packet can be realized as early as possible, and the service interruption time delay of the terminal is reduced.

In a second aspect, the present embodiments provide a communication method, which may be performed by a first IAB node or a module (e.g., a chip) applied in the first IAB node, where the first IAB node is a subordinate node of a migrating IAB node. Taking the first IAB node as an example to execute the method, the first IAB node determines that a first condition is satisfied, the first condition comprising: the first IAB node receives first indication information or a first RRC message from a second IAB node, the second IAB node being a parent node of the first IAB node, 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 second indication information to a third IAB node, wherein the second indication information is used for triggering a second RRC message in the third IAB node to take effect. Alternatively, when the first condition is satisfied, the first IAB node sends the second RRC message to the third IAB node, which is a child node of the first 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, the second RRC message includes second configuration information used for transport network layer migration between the third IAB node and the IAB host CU, and the first IAB node is connected to the IAB host CU through different IAB host DUs before and after transport network layer migration.

According to the above scheme, after receiving the first RRC message or the first indication message from the second IAB node, the first IAB node may start to perform transport network layer migration on the one hand, and on the other hand, immediately send the second RRC message or the second indication message to the child node of the first IAB node on the other hand, so as to trigger the child node of the first IAB node to start to perform transport network layer migration as early as possible, which may avoid that the service interruption delay of the terminal is too long due to the child node of the first IAB node performing transport network layer migration too late, thereby reducing the service delay impact on the terminal served by the IAB node, and improving communication efficiency.

As a possible implementation method, the first condition further includes: the first IAB node does not receive first information from the second IAB node, the first information being used for data transmission after the first IAB node migrates in the transport network layer, the first information including one or more of a BAP route mapping configuration, a BH RLC CH mapping configuration, or a BAP route identification configuration.

According to the above scheme, it is limited that the first IAB node sends the second RRC message to the third IAB node before receiving the first message from the second IAB node, so that the third IAB node can start to perform transport network layer migration as early as possible, and it is avoided that the service interruption delay of the terminal is too long due to the fact that the child node of the first IAB node performs transport network layer migration too late, thereby reducing the influence of the service delay on the terminal served by the IAB node, and improving the communication efficiency.

According to the scheme, the first IAB node is prevented from sending the second RRC message to the third IAB node after the transmission network layer migration is completed, so that the situation that the service interruption time delay of the terminal is too long due to the fact that the third IAB node executes the transmission network layer migration too late can be avoided, the service time delay influence on the terminal served by the IAB node is reduced, and the communication efficiency can be improved.

As a possible implementation method, the first configuration information includes a first BAP routing identifier. And the first IAB node receives an uplink data packet, wherein the uplink data packet comprises a second BAP routing identifier. And 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.

According to the above solution, after the migration IAB node is switched to the target parent node and before the transport network layer migration between the migration IAB node and the IAB host node-CU is completed, the first IAB node may use the first BAP routing identifier to route the uplink data packet if the BAP address in the uplink data packet is the same as the BAP address in the first BAP routing identifier after the first IAB node receives the uplink data packet. Therefore, the received uplink data packet can be ensured to be successfully sent, and the packet loss is avoided. And the transmission of the uplink data packet can be realized as early as possible, and the service interruption time delay of the terminal is reduced.

As a possible implementation method, 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 does not receive the first information from the second IAB node, the first IAB node sends the uplink data packet according to the first BAP routing identifier. The first information is used for data transmission after the first IAB node is switched, and the first information includes one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

According to the scheme, before the BAP routing configuration information is received on the target path, the routing of the data packet can not be performed according to the BAP routing configuration information on the target path, but the method can be used, and the first IAB node uses the first BAP routing identifier of the first IAB node to route the received uplink data packet, so that the received uplink data packet can be ensured to be successfully sent, and the occurrence of packet loss is avoided.

As a possible implementation method, the first configuration information further includes an identifier of the BH RLC CH. The first IAB node determines a next hop node of the first IAB node corresponding to the first BAP routing identifier. The first IAB node sends the uplink packet to the next hop node on the BH RLC CH.

As a possible implementation, the next hop node is a default parent node of the first IAB node. Or, the first configuration information further includes an identifier of the next hop node.

As a possible implementation method, the first IAB node receives a downlink data packet, where the downlink data packet includes a third BAP routing identifier. And the first IAB node determines that the first RRC message is received and the first IAB node does not receive the first information from the IAB host CU, and determines a next hop node of the first IAB node according to the BAP address in the third BAP routing identifier. 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 is switched, and the first information includes one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

In a third aspect, an embodiment of the present application provides a communication apparatus, which may be an IAB node, and may also be a chip for the IAB node. The apparatus has a function of implementing any of the implementation methods of the first to second aspects described above. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In a fourth aspect, an embodiment of the present application provides a communication apparatus, including a processor and a memory; the memory is used for storing computer instructions, and when the apparatus runs, the processor executes the computer instructions stored in the memory, so that the apparatus executes any implementation method in the first aspect to the second aspect.

In a fifth aspect, an embodiment of the present application provides a communication apparatus, which includes means or units (means) for performing each step of any implementation method in the first aspect to the second aspect.

In a sixth aspect, an embodiment of the present application provides a communication device, which includes a processor and an interface circuit, where the processor is configured to communicate with another device through the interface circuit, and perform any implementation method in the first aspect to the second aspect. The processor includes one or more.

In a seventh aspect, an embodiment of the present application provides a communication apparatus, including a processor coupled to a memory, where the processor is configured to invoke a program stored in the memory to execute any implementation method in the first aspect to the second aspect. The memory may be located within the device or external to the device. And the processor may be one or more.

In an eighth aspect, the present invention further provides a computer-readable storage medium, which stores instructions that, when executed on a communication device, cause any implementation method in the first aspect to the second aspect to be performed.

In a ninth aspect, the present application further provides a computer program product, which includes a computer program or instructions, and when the computer program or instructions are executed by a communication device, the method of any implementation method in the first aspect to the second aspect is executed.

In a tenth aspect, an embodiment of the present application further provides a chip system, including: a processor configured to perform any of the implementation methods of the first to second aspects.

Drawings

Fig. 1 is a schematic view of an IAB independent networking scenario;

FIG. 2 is a schematic diagram of an IAB dependent networking scenario;

FIG. 3 is a schematic diagram of an IAB network user plane protocol stack;

FIG. 4 is a diagram of an IAB network control plane protocol stack;

FIG. 5 is a schematic diagram of topology updates within an IAB network host;

FIG. 6 is a schematic diagram of an IAB network updating across a hosting topology;

fig. 7 (a) is a schematic flowchart of a communication method according to an embodiment of the present application;

fig. 7 (b) is a schematic flowchart of a communication method provided in an embodiment of the present application;

fig. 8 (a) is a schematic flowchart of a communication method provided in an embodiment of the present application;

fig. 8 (b) is a schematic flowchart of a communication method provided in an embodiment of the present application;

fig. 9 is a schematic flowchart of a data transmission method according to an embodiment of the present application;

fig. 10 is a schematic flowchart of a data transmission method according to an embodiment of the present application;

fig. 11 is a schematic flowchart of a data transmission method according to an embodiment of the present application;

fig. 12 is a schematic flowchart of a data transmission method according to an embodiment of the present application;

fig. 13 is a schematic flowchart of a data transmission method according to an embodiment of the present application;

fig. 14 is a schematic diagram of a communication device according to an embodiment of the present application;

fig. 15 is a schematic diagram of a communication device according to an embodiment of the present application.

Detailed Description

Compared with the fourth generation (4 th generation, 4G) mobile communication system, the fifth generation (5 th generation, 5G) mobile communication provides more severe requirements for various performance indexes of the network in all directions. For example, the capacity index is improved by 1000 times, the coverage requirement is wider, the performance is ultrahigh, reliable and ultralow in time delay and the like. On one hand, in consideration of rich high-frequency carrier frequency resources, in a hot spot area, in order to meet the requirement of 5G ultrahigh capacity, networking by using high-frequency small stations is more popular. The high-frequency carrier wave has poor propagation characteristics, serious shielding attenuation and low coverage range, so a large number of densely deployed small stations are required. Accordingly, it is very costly and difficult to construct the optical fiber backhaul provided for these numerous densely deployed small stations, and therefore an economical and convenient backhaul scheme is required. On the other hand, from the perspective of wide coverage requirements, network coverage is provided in some remote areas, the deployment difficulty of optical fibers is high, the cost is high, and flexible and convenient access and backhaul schemes also need to be designed. The IAB technique provides ideas for solving the two problems: an access link (access link) and a backhaul link (backhaul link) both adopt wireless transmission schemes, so that optical fiber deployment is avoided.

Referring to fig. 1, a schematic diagram of an IAB independent (SA) networking scenario is shown. The IAB node and the User Equipment (UE) both establish a connection with the network through a New Radio (NR) air interface. In the IAB network, an IAB node (IAB node), which may also be referred to as a Relay Node (RN), may provide a radio access service for a UE, and service data of the UE is transmitted by the IAB node through a radio backhaul link connected to an IAB donor node (IAB node). The IAB donor node may also be referred to as a donor node or a donor base station (donor gnnodeb, dgNB) in this application.

The IAB node includes a Mobile Termination (MT) portion and a Distributed Unit (DU) portion. The MT part of the IAB node has some or all of the functionality of the UE and may be used to provide data backhaul for its child nodes. The DU part of an IAB node can be used to provide access services to its children. The MT portion of the IAB node may be referred to as the IAB-MT, and the DU portion of the IAB node may be referred to as the IAB-DU. An IAB node may communicate with its parent node through an MT part in the IAB node, which is now considered a UE. An IAB node may communicate with its children through the DU portion of the IAB node, when the IAB node is considered a network device. The child node of the IAB node may be another IAB node or a normal UE.

The IAB node may be divided into an access IAB node and an intermediate IAB node, where the IAB node accessed by the UE is referred to as an access IAB node, and the IAB node on the path between the access IAB node and the IAB host node is referred to as an intermediate IAB node. For example, IAB node 4 and IAB node 5 in fig. 1 are referred to as access IAB nodes, and IAB node 1, IAB node 2, and IAB node 3 are referred to as intermediate IAB nodes.

The IAB host node may be an access network element having part or all of the functions of the base station, and may also be an access network element including a Centralized Unit (CU) and a DU. The IAB donor node may connect to a core network serving the UE (e.g., to a 5G core network) and provide wireless backhaul functionality for the IAB node. In the embodiment of the present application, a CU in an IAB donor node may be referred to as an IAB donor CU, an IAB donor node-CU, a donor node-CU, or a donor CU, and a DU of the IAB donor node may be referred to as an IAB donor DU, an IAB donor node-DU, a donor node-DU, or a donor DU. It is also possible that the donor CU is in a separate form of a Control Plane (CP) and a User Plane (UP), e.g. the donor CU comprises one CU-CP and at least one CU-UP.

In the embodiment of the present application, a terminal may also be referred to as a terminal device, a UE, a mobile station, a mobile terminal, or the like. The terminal can be widely applied to various scenes, for example, device-to-device (D2D), vehicle-to-equipment (V2X) communication, machine-type communication (MTC), internet of things (IOT), virtual reality, augmented reality, industrial control, automatic driving, telemedicine, smart grid, smart furniture, smart office, smart wearing, smart transportation, smart city, and the like. The terminal can be cell-phone, panel computer, take the computer of wireless transceiving function, wearable equipment, vehicle, unmanned aerial vehicle, helicopter, aircraft, steamer, robot, arm, intelligent house equipment etc.. The embodiment of the present application does not limit the specific technology and the specific device form adopted by the terminal.

In the current 5G standard, considering that the coverage area of the high frequency band is small, in order to ensure the coverage performance of the network, multi-hop networking may be adopted in the IAB network. In addition, considering the requirement of service transmission reliability, the IAB node may be made to support Dual Connectivity (DC) or multi-connectivity (multi-connectivity) to cope with the abnormal situation that may occur in the backhaul link. For example, the transmission reliability is ensured by the abnormity of the interruption or blocking (block) of the link and the load fluctuation. Therefore, the IAB network supports multi-hop networking and may also support multi-connection networking. Between a UE served by an IAB node and the IAB donor node, there is at least one transmission path consisting of multiple segments of links. A plurality of nodes, such as a UE, one or more IAB nodes, and an IAB donor node (if the IAB donor node is in a form in which the CU and the DU are separated, the IAB donor node is replaced with an IAB donor node-DU and an IAB donor node-CU) are included in one transmission path. Each IAB node treats neighboring nodes that provide access and backhaul services for the IAB node as parent nodes, and accordingly, each IAB node may be considered a child node of its parent node.

For example, in fig. 1, the IAB donor node is a parent node of the IAB node 1, and the IAB node 1 is a child node of the IAB donor node. IAB node 1 is a parent node of IAB node 2 and IAB node 3, and IAB node 2 and IAB node 3 are child nodes of IAB node 1. IAB node 2 is a parent node of IAB node 4 and IAB node 5, and IAB node 4 and IAB node 5 are child nodes of IAB node 2. IAB node 3 is a parent node of IAB node 4 and IAB node 4 is a child node of IAB node 3.

In the uplink direction, an uplink data packet of the UE may be transmitted to the IAB host node through one or more IAB nodes, and then sent to the mobile gateway device (e.g., a User Plane Function (UPF) in a 5G core network) by the IAB host node. In the downlink direction, the IAB host node receives the downlink data packet from the mobile gateway device and then sends the downlink data packet to the UE through the IAB node.

The scenario of IAB independent networking shown in fig. 1 is only exemplary, and in the scenario of an IAB with a combination of multi-hop and multi-connection, there are still more other possibilities, for example, the IAB host node in fig. 1 may form a dual connection with an IAB node under another IAB host node to provide a service for the UE, that is, the UE supports dual connection, where one connection 1 is that the UE accesses to a cell served by the IAB host node-DU in fig. 1 through the IAB node in fig. 1, and another connection 2 is that the UE establishes a connection with an IAB node X, and the IAB host connected to the IAB node X is different from the IAB host node corresponding to the connection 1.

Referring to fig. 2, a schematic diagram of an IAB non-independent (NSA) networking scenario is shown. The IAB node supports dual connectivity for 4G and 5G networks. A base station (eNB) of a Long Term Evolution (LTE) is a master base station (master eNB, meNB), and the eNB provides an air interface (LTE Uu) connection of the LTE for an IAB node, and establishes an S1 interface with a 4G core network (evolved packet core, EPC) to perform user plane and control plane transmission. The IAB donor node is an auxiliary base station, may be a gNB of 5G, may provide an NR air interface (i.e., NR Uu) connection for the IAB node, and establishes an S1 interface with the EPC to perform user plane transmission. The UE is connected to the primary base station (i.e. eNB) over an LTE Uu interface and to the secondary base station (which may be an IAB node or an IAB donor node) over an NR Uu interface.

It should be noted that fig. 2 is only an example of networking, and the NSA scenario of the IAB network also supports multi-hop IAB networking, for example, one or more IAB nodes may be added between the UE and the IAB node in fig. 2, that is, the IAB node may be connected to the IAB host node through a multi-hop wireless backhaul link.

In the current IAB network, a new protocol layer, i.e., a Backhaul Adaptation Protocol (BAP) layer, is introduced into a wireless backhaul link, and the BAP layer is located above a Radio Link Control (RLC) layer, and can be used to implement functions such as routing and bearer mapping of a data packet in the wireless backhaul link.

An F1 interface is established between the DU part of the IAB node and the IAB home node-CU, the F1 interface supporting user plane protocols (F1-U) and control plane protocols (F1-C). Wherein the user plane protocols include one or more of the following: general Packet Radio Service (GPRS) tunneling protocol user plane (GTP-U) protocol, user Datagram Protocol (UDP), internet Protocol (IP). The control plane protocols include one or more of the following: f1 application protocol (F1 AP), stream Control Transport Protocol (SCTP), and IP protocol.

Referring to fig. 3, a schematic diagram of an IAB network user plane protocol stack is shown. If the IAB home node adopts the CP-UP separation structure, an F1-U interface is established between the DU part of the IAB nodes (such as the IAB node 1 and the IAB node 2 shown in the figure 3) and the IAB home node-CU-UP. And for the access IAB node, also establish a GTP tunnel of UE bearer granularity (per UE bearer) over the F1-U interface between the access IAB node and the IAB host node-CU-UP. That is, each UE DRB established on the interface between the DU of the UE and 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.

Referring to fig. 4, a schematic diagram of a control plane protocol stack of the IAB network is shown. If the IAB host node adopts the CP-UP separation architecture, an F1-C interface is established between the DU part of the IAB nodes (such as the IAB node 1 and the IAB node 2 shown in the figure 4) and the IAB host node-CU-CP. Radio Resource Control (RRC) messages for the UE are transmitted encapsulated in F1AP messages for the F1-C interface.

Currently, IAB nodes are allowed to perform topology updates within the scope of a single IAB home node-CU service. Referring to fig. 5, a schematic diagram of topology update in an IAB network host is shown. The IAB node 1 is used as a migration IAB node, is connected to a source parent node before topology updating, then needs to perform topology updating due to reasons such as link quality deterioration or load sharing between the IAB node 1 and the source parent node (i.e., the IAB node 5), and after the topology updating, the IAB node 1 is accessed to a target parent node (i.e., the IAB node 6) and is communicated with an IAB host node through the target parent node.

Considering that the IP address of the IAB node is related to the IAB home node-DU to which the IAB node is connected in the IAB network, if the IAB home node-DU to which the target parent node of the IAB node 1 is connected is different from the IAB home node-DU to which the source parent node of the IAB node 1 is connected during the topology update process, the IAB node 1 needs to configure different IP addresses before and after migration. That is, the IP address of the IAB node 1 is associated with the IAB donor node-DU 1 when the IAB node 1 is connected to the source parent node, and even the IP address of the IAB node 1 may be allocated by the IAB donor node-DU 1, and the IP address of the IAB node 1 is associated with the IAB donor node-DU 2 when the IAB node 1 is connected to the target parent node, and even the IP address of the IAB node 1 may be allocated by the IAB donor node-DU 2.

In addition to the IAB node 1, subordinate nodes of the IAB node 1, such as the descendant node IAB node 2, the descendant node IAB node 4, etc., need to be configured with new IP addresses following the connection of the IAB node 1 to the IAB home node-DU 2.

In the embodiment of the present application, the "grandchild node" refers to a child node of the child node, and taking fig. 5 as an example, the child node of IAB node 1 includes IAB node 2, and the child node of IAB node 2 includes IAB node 4, so that IAB node 4 is a grandchild node of IAB node 1, and accordingly, IAB node 1 may be referred to as a grandparent node of IAB node 4. The description is unified here and will not be described in detail later.

In the embodiment of the present application, the "subordinate node of the migrated IAB node" includes a child node of the migrated IAB node and a node below the child node, or is understood to be an IAB node on a transmission path between the UE and the migrated IAB node. Specifically, the subordinate nodes of the migration IAB node include child nodes, grandchild nodes, child nodes of grandchild nodes, grandchild nodes of grandchild nodes, etc., and so on. Taking fig. 5 as an example, IAB node 1 is a migrating IAB node, and the subordinate nodes of IAB node 1 include IAB node 2, IAB node 3, and IAB node 4. In the embodiment of the present application, a subordinate node of the migration IAB node is also referred to as a subordinate IAB node of the migration IAB node, or a downstream IAB node of the migration IAB node. The description is unified here and will not be described in detail later. After configuring the new IP address, the IAB node may establish a new transport network layer association (association) with the IAB host node-CU by using the new IP address, and perform internet protocol security (IPsec) security negotiation again. The F1-C connection between the DU part of the IAB node and the IAB host node CU and the GTP-U tunnel of the F1-U are then migrated onto the new transmission path and the new IP address is used on the new transmission path.

In this embodiment, a process of establishing a Stream Control Transmission Protocol (SCTP) layer connection (or referred to as transmission network layer coupling or SCTP coupling) on a new transmission path by the IAB node using a new IP address and/or performing IPsec anew is referred to as transport network layer migration of the IAB node.

Transport network layer migration for an IAB node may also include any one or more of: and bearing the control plane of the F1 interface of the IAB node on the SCTP layer coupling established on the new transmission path, and migrating the user plane of the F1 interface of the IAB node to the new transmission path. Wherein, when the control plane of the F1 interface of the IAB node is carried on the SCTP layer coupling established on the new transmission path, the coupling will use a new IP address on the new SCTP layer coupling. When the user plane of the F1 interface of the IAB node is migrated to a new transmission path, the GTP-U tunnel in the F1-U will use a new IP address.

The migration IAB node and the subordinate nodes of the migration IAB node are required to perform transport network layer migration.

The above describes the topology update procedure of the IAB node within the scope of one IAB host node-CU service. In another scenario, there is also a topology upgrade problem for IAB node migration across IAB host nodes. Referring to fig. 6, a schematic diagram of an IAB network updating across a hosting topology is shown. The IAB host node 1 is a migration IAB node, the IAB host node 1 is a source IAB host node, the IAB host node 1 includes an IAB host node-CU 1 and an IAB host node-DU 1, the IAB host node 2 is a target IAB host node, and the IAB host node 2 includes an IAB host node-CU 2 and an IAB host node-DU 2. The migrating IAB node is connected to a source parent node (i.e., IAB node 5) managed by the source IAB hosting node before the topology update, and connected to a target parent node (i.e., IAB node 6) managed by the target IAB hosting node after the topology update.

In this embodiment, the migration IAB node in the scenario of updating the inter-hosting topology of the IAB network may also be referred to as a border node, a source parent node and a target parent node of the border node are connected to different IAB hosting nodes-DUs, and the different IAB hosting nodes-DUs are attributed to different IAB hosting nodes-CUs, or an F1 interface is provided between the different IAB hosting nodes-DUs and the different IAB hosting nodes-CUs.

As an implementation method, it may be considered that only the MT part of the migrating IAB node is updated to be managed by the target IAB home node (or the RRC connection of the MT part of the migrating IAB node is migrated to the target IAB home node), while the DU part of the migrating IAB node and its subordinate nodes are still controlled by the source IAB home node (or the DU part of the migrating IAB node and its subordinate nodes are still connected to the source IAB home node). For example, referring to fig. 6, before the topology update, the IAB node 1 and the subordinate nodes of the IAB node 1 are both managed by the IAB host node 1, after the topology update, the MT part of the IAB node 1 is managed by the IAB host node 2, and the DU part of the IAB node 1 and the subordinate nodes of the IAB node 1 are still managed by the IAB host node 1. Based on the implementation method, since the parent node of the migration IAB node is updated, the transmission path is also changed, so that after the topology is updated, the F1 connection between the DU part of the migration IAB node and the IAB host node-CU 1 needs to be migrated to a new transmission path, and the new transmission path is as shown in fig. 6, so that a transport network layer migration process needs to be executed. Accordingly, if the child node of the migrating IAB node also needs to perform the transport network layer migration procedure. That is, the transport network layer migration process needs to be executed by both the migrating IAB node and the subordinate nodes of the migrating IAB node.

As can be seen from the above description, regardless of the topology update within a single IAB host or the topology update across IAB hosts, transport network layer migration needs to be performed for the migrating IAB node and the subordinate nodes of the migrating IAB node.

In order to implement transport network layer migration of a subordinate node of an migrating IAB node, two different methods are provided in the embodiments of the present application, which are as follows.

The method comprises the steps that firstly, an IAB host node-CU encapsulates configuration information required by the subordinate nodes of the migrating IAB node to execute transport network layer migration in RRC messages, and sends the RRC messages of the subordinate nodes to parent nodes of all the subordinate nodes from a source transmission path in advance, and the parent nodes cache the RRC messages and send the RRC messages to the corresponding subordinate nodes after first conditions (also called triggering conditions) are met. After each IAB node receives the RRC message of the IAB node, the IAB node executes configuration according to the configuration information in the RRC message and initiates transport network layer migration.

In this embodiment, the RRC message appearing anywhere may be an RRC configuration message or an RRC reconfiguration message, which is described in a unified manner and is not described in detail herein again.

For example, in fig. 5, the migrating 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 message of the IAB node 2 and the RRC message of the IAB node 3 in the F1AP message sent to the IAB node 1-DU (for example, may be carried in the same F1AP message or may be carried in different F1AP messages, respectively), the IAB node 1 first caches the RRC message of the IAB node 2 and the RRC message of the IAB node 3, and the IAB node 1 may specifically cache the RRC message of the IAB node 2/3 according to the indication information in the F1AP message carrying the RRC message of the IAB node 2/3. After meeting the first condition, the IAB node 1 sends the RRC message of the IAB node 2 to the IAB node 2, sends the RRC message of the IAB node 3 to the IAB node 3, the IAB node 2 initiates transport network layer migration according to the configuration information in the RRC message after receiving the RRC message of itself, and the IAB node 3 initiates transport network layer migration according to the configuration information in the RRC message after receiving the RRC message of itself.

Similarly, the IAB donor node-CU can first carry the IAB node 4 RRC message in the F1AP message sent to the IAB node 2-DU and/or in the F1AP message sent to the IAB node 3-DU. IAB node 2 and/or IAB node 3 first buffers IAB node 4 RRC messages. After the first condition is satisfied, the IAB node 2 and/or the IAB node 3 then sends the RRC message of the IAB node 4 to the IAB node 4. After receiving the RRC message, the IAB node 4 initiates transport network layer migration according to the configuration information in the RRC message.

And the second implementation method is that the IAB host node-CU encapsulates the configuration information required by the subordinate nodes of the migrating IAB node to execute the transport network layer migration in RRC messages, and sends the RRC messages of the subordinate nodes to each subordinate node from a source transmission path in advance. After receiving the RRC message of the subordinate node, the subordinate node does not take effect on the RRC message, but after receiving the indication information which is sent by the father node of the subordinate node and used for indicating that the cached RRC message is taken effect, the subordinate node initiates transport network layer migration according to the configuration information in the cached RRC message. And when the parent node of the subordinate node is determined to meet the first condition, the indication information is sent to the subordinate node.

For example, in fig. 5, the migrating 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 firstly carries the RRC message of the IAB node 2 in the F1AP message sent to the IAB node 1-DU, the IAB node 1 sends the RRC message of the IAB node 2 carried in the F1AP message to the IAB node 2, the IAB node 2 firstly caches the RRC message but does not take effect on the configuration information in the RRC message, and after receiving the indication information sent by the IAB node 1, the IAB node 2 initiates 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 the IAB node 3 in the F1AP message sent to the IAB node 1-DU, the IAB node 1 sends the RRC message of the IAB node 3 carried in the F1AP message to the IAB node 3, the IAB node 3 first buffers the RRC message but does not take effect on the configuration information in the RRC message, and after receiving the indication information sent by the IAB node 1, the IAB node 3 initiates transport network layer migration according to the configuration information in the buffered RRC message. Similarly, the IAB host node-CU first carries the RRC message of the IAB node 4 in the F1AP message sent to the IAB node 2-DU or the IAB node 3-DU, the IAB node 2 or the IAB node 3 sends the RRC message of the IAB node 4 carried in the F1AP message to the IAB node 4, the IAB node 4 first buffers the RRC message, and after receiving the indication information sent by the IAB node 2 or the IAB node 3, the IAB node 4 initiates transport network layer migration according to the configuration information in the buffered RRC message.

The first implementation method and the second implementation method are suitable for topology updating scenes in a single IAB network host and topology updating scenes across IAB network hosts.

The same problem is faced regardless of whether the transport network layer migration of the IAB node is realized by the first implementation method or the transport network layer migration of the IAB node is realized by the second implementation method: how should the first condition be set? I.e. when the subordinate node that triggered the migration of the IAB node performs transport network layer migration?

If the first condition is set unreasonable, the timing for the subordinate node of the migration IAB node to perform transport network layer migration may be too early, for example, before the migration IAB node has not yet accessed the target parent node of the migration IAB node, the subordinate node of the migration IAB node starts to attempt to perform transport network layer migration, which may cause the subordinate node of the migration IAB node to fail to perform transport network layer migration.

If the first condition is set unreasonably, the time for the subordinate nodes of the migration IAB node to perform transport network layer migration may also be too late, for example, after the migration IAB node has accessed to the target parent node of the migration IAB node and the migration IAB node has completed transport network layer migration, the subordinate nodes of the migration IAB node sequentially perform transport network layer migration, and the transport network layer migration waiting time of these subordinate nodes will be too long. Especially, when the migration IAB node has a plurality of hierarchical subordinate nodes, the time from the completion of the transport network layer migration by the migration IAB node to the completion of the transport network layer migration by the subordinate node of the migration IAB node is long, which brings a great influence to the interruption of the service of the UE (especially, the UE accessing to the serving cell of the subordinate node).

From the above analysis, it can be seen that the selection of the timing for executing the transport network layer migration by the subordinate node of the migration IAB node is very important, and therefore how to reasonably set the first condition to instruct the subordinate node of the migration IAB node to execute the transport network layer migration at a proper timing needs to be solved.

In order to implement that a subordinate node of a migration IAB node is instructed to execute transport network layer migration at a proper time, an embodiment of the present application provides a communication method, where the method corresponds to the first implementation method, and the first condition that needs to be met when the migration IAB node sends an RRC message to a child node of the migration IAB node is provided in the first implementation method.

The method is suitable for topology updating scenes in an IAB network host and topology updating scenes across the IAB network host.

Referring to fig. 7 (a), the method includes the steps of:

in step 701a, the first IAB node determines that a first condition is satisfied.

The first IAB node herein refers to a migrating IAB node, such as IAB node 1 in fig. 5 or fig. 6.

The first condition includes:

condition 1): the first IAB node receives a first RRC message from the IAB donor CU.

Condition 2): 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.

Both of the above conditions 1) and 2) need to be satisfied.

Wherein the first RRC message includes first configuration information for transport network layer migration between the first IAB node and the IAB host CU. The first RRC message may also be referred to as an RRC message of the first IAB node. Taking fig. 5 or fig. 6 as an example, when the IAB node 1 receives the RRC message of the IAB node 1, and the IAB node 1 switches from the source parent node (i.e., the IAB node 5) to the target parent node (i.e., the IAB node 6) for successful access according to the RRC message of the IAB node 1, the IAB node 1 determines that the first condition is satisfied.

The source father node and the target father node of the first IAB node are connected to different IAB host nodes-DUs, and the first IAB node is connected to the same IAB host node-CU through the different IAB host nodes-DUs before and after switching. Referring to the intra-IAB network home topology update scenario shown in fig. 5 or the inter-IAB network home topology update scenario shown in fig. 6, the migration IAB node is the IAB node 1, the source parent node before the switching of the IAB node 1 is the IAB node 5, the IAB node 5 is connected to the IAB home node-DU 1, the target parent node after the switching of the IAB node 1 is the IAB node 6, the IAB node 6 is connected to the IAB home node-DU 2, and the IAB home node-DU 1 and the IAB home node-DU 2 are different IAB home nodes-DU. The IAB node 1 is connected to the IAB home node-CU through an IAB home node-DU 1 before handover, and the IAB node 1 is also connected to the IAB home node-CU through an IAB home node-DU 2 after handover. In the scenario of fig. 5, the IAB home node-DU 1 and the IAB home node-DU 2 connected to the IAB node 1 before and after the handover are managed by the same IAB home node-CU, whereas in the scenario of fig. 6, the IAB home node-DU 1 and the IAB home node-DU 2 connected to the IAB node 1 before and after the handover are managed by different IAB home nodes-CUs.

In step 702a, when the first condition is satisfied, the first IAB node sends a second RRC message to the second IAB node. Accordingly, the second IAB node receives the second RRC message.

The second IAB node is a child node of the first IAB node. Taking fig. 5 or fig. 6 as an example, the first IAB node is IAB node 1, and the second IAB node is IAB node 2 or IAB node 3.

The second RRC message includes second configuration information for transport network layer migration between the second IAB node and the IAB host CU. The second RRC message may also be referred to as an RRC message of the second IAB node.

The second IAB node may begin performing transport network layer migration after receiving the second RRC message. Taking fig. 5 or fig. 6 as an example, after IAB node 2 receives the RRC message of IAB node 2 from IAB node 1, the transport network layer migration may be started according to the RRC message of IAB node 2. As an implementation method, after receiving the second RRC message, the second IAB node may start to perform transport network layer migration, which specifically includes: after receiving the second RRC message, the MT part of the second IAB node performs reconfiguration according to the second configuration information in the second RRC message, and then the MT part of the second IAB node sends an RRC reconfiguration complete (rrcreeconfiguration complete) message to the IAB host node-CU, and if the second RRC message carries configuration information related to transport network layer migration, the second IAB node performs transport network layer migration again. Here, the case that the second IAB node performs transport network layer migration is taken as an example for description, and for other nodes that need to perform transport network layer migration, transport network layer migration may also be performed according to the method, which is described in a unified manner and is not described in detail later.

According to the above scheme, after the first IAB node receives the first RRC message from the IAB host CU and the first IAB node is switched from the source parent node of the first IAB node to the target parent node of the first IAB node according to the first RRC message, the second IAB node is then sent the second RRC message to trigger the second IAB node to perform transport network layer migration according to the second RRC message, so that it is avoided that the second IAB node starts to perform transport network layer migration before the first IAB node is successfully switched to the target parent node of the first IAB node, and therefore it is avoided that the second IAB node fails to perform transport network layer migration too early, thereby reducing the traffic delay impact on the UE served by the IAB node, and improving communication efficiency.

As an implementation method, on the basis that the first condition includes the above condition 1) and condition 2), the first condition further includes the following condition 3):

condition 3): the first IAB node does not receive the first information from the IAB donor node-CU.

The first IAB node does not receive the first information from the IAB donor node-CU, which may also be understood as being before the first IAB node receives the first information from the IAB donor node-CU.

The first information is used for data transmission after the first IAB node is handed over, where the data transmission may be data transmission of a user plane or signaling transmission of a control plane. The first information may also be referred to as BAP routing configuration information on the target path, or as updated BAP routing configuration.

The first information includes one or more of a BAP route mapping configuration, a backhaul radio link control channel (BH RLC CH) mapping configuration, or a BAP route identification configuration.

The BAP routing mapping configuration comprises an updated routing mapping table to be used by a BAP layer of the first IAB node based on a new network topology after the first IAB node performs handover, and the updated routing mapping table is used for routing an uplink data packet or a downlink data packet on the BAP layer after the first IAB node performs handover. One or more entries are included in the updated route mapping table, where each entry includes a BAP routing identification (BAP routing ID) and an identification of a next-hop node (e.g., a BAP address of the next-hop node) corresponding to the BAP routing identification.

And the BH RLC CH mapping configuration comprises an updated BH RLC CH mapping relation to be used by a BAP layer of the first IAB node based on a new network topology after the first IAB node performs switching, wherein the updated BH RLC CH mapping relation is used for performing quality of service (QoS) mapping on an uplink data packet or a downlink data packet on the BAP layer after the first IAB node performs switching, and a proper BH RLC CH is selected for the uplink data packet or the downlink data packet to be sent. As an implementation method, the updated BH RLC CH mapping relationship may include any one or more of the following: the identification of each GTP-U tunnel of an F1 interface maintained by a first IAB node in uplink data transmission and the identification of a BH RLC CH of a corresponding exit link; type information of each non-F1-U service type of a first IAB node in uplink data transmission (specifically, the type information can be F1-C interface information related to UE, F1-C interface information unrelated to UE, non-F1 type information, BAP control PDU and the like) and a mark of a BH RLC CH of an egress link corresponding to the type information; in uplink or downlink data transmission, the identifier of the BH RLC CH of the ingress link of the first IAB node and the identifier of the BH RLC CH of the egress link corresponding thereto.

And the BAP routing identification configuration comprises one or more BAP routing IDs to be used by the BAP layer of the first IAB node based on the new network topology after the first IAB node performs handover, wherein the one or more BAP routing IDs are the BAP routing IDs added by the upstream data packets which are to be submitted by the first IAB node at the BAP layer for the upper protocol layer of the BAP layer (for example, the IP layer of the DU of the first IAB node). As an implementation method, the BAP route identifier configuration may include any one or more of the following: the identification of each GTP-U tunnel of an F1 interface maintained by a first IAB node in uplink data transmission and a corresponding BAP routing ID; the type information of each non-F1-U service type of the first IAB node in uplink data transmission (specifically, may be an F1-C interface message related to the UE, an F1-C interface message unrelated to the UE, a non-F1 type message, a BAP control PDU, etc.) and a BAP routing ID corresponding thereto.

In this application, the identifier of the BH RLC CH of the egress link of the IAB node may be 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 identity of the BH RLC CH of the entry link of the IAB node may be identified by the BAP address of the previous hop node of the IAB node corresponding to the entry link and the BHRLC CH ID on the entry link. The identifier of each GTP-utu tunnel of the F1 interface maintained by the IAB node may be identified by a Tunnel End Identifier (TEID) of the GTP-U tunnel and an upstream destination IP address, where the TEID is allocated by an IAB host node-CU (in a scenario where the IAB host node-CU is CP-UP split, specifically, the IAB host node-CU-UP) that establishes the F1-U interface with the IAB node, and the upstream destination IP address is an IP address of the IAB host node-CU (or the IAB host node-CU-UP).

If the first IAB node receives the first information from the IAB host node-CU, the IAB host node-CU finishes the route updating of the IAB network after the switching of the first IAB node, and the first information is obtained. Therefore, through the condition 3), it is limited that the first IAB node sends the second RRC message to the second IAB node before receiving the first information from the IAB host node-CU, so that the second IAB node can start to perform transport network layer migration as early as possible, and it can be avoided that the service interruption delay of the UE is too long due to the late execution of transport network layer migration by the second IAB node, thereby reducing the service delay influence on the UE served by the IAB node, and improving the communication efficiency.

In general, the first IAB node receives the F1AP message carrying the first information from the IAB host-CU after the transport network layer migration of the first IAB node is completed. Thus, the first IAB node generally does not receive the first information until the transport network layer migration of the first IAB node is complete.

As an implementation method, on the basis that the first condition includes the above condition 1) and condition 2), or on the basis that the first condition includes the above condition 1), condition 2), and condition 3), the first condition further includes the following condition 4):

condition 4): the first IAB node does not complete transport network layer migration between the first IAB node and the IAB host node-CU according to the first configuration information.

The first IAB node does not complete transport network layer migration between the first IAB node and the IAB donor node-CU according to the first configuration information, which can also be understood as before the first IAB node completes transport network layer migration between the first IAB node and the IAB donor node-CU according to the first configuration information.

Through the condition 4), it is avoided that the first IAB node starts sending the second RRC message to the second IAB node after completing the transport network layer migration, so that it is avoided that the service interruption delay of the UE is too long due to the fact that the second IAB node performs the transport network layer migration too late, thereby reducing the service delay impact on the UE served by the IAB node, and improving the communication efficiency.

In order to implement that a subordinate node of an migrating IAB node is instructed to execute transport network layer migration at a proper time, an embodiment of the present application provides a communication method, where the method corresponds to the first implementation method, and the first condition that needs to be met when the subordinate node of the migrating IAB node sends an RRC message to a child node of the subordinate node is provided in the first implementation method.

Referring to fig. 7 (b), the method includes the steps of:

in step 701b, the first IAB node determines that a first condition is satisfied.

The first IAB node herein refers to a subordinate node of the migrating IAB node, such as IAB node 2 or IAB node 3 in fig. 5 or fig. 6.

The first condition includes:

condition 1): the first IAB node receives a first RRC message from the second IAB node.

Wherein the second IAB node is a parent node of the first IAB node. For example, referring to fig. 5 or 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.

The first RRC message includes first configuration information for transport network layer migration between the first IAB node and the IAB host node-CU. The first IAB node may begin performing transport network layer migration after receiving the first RRC message.

Wherein the first IAB node is connected to the IAB host node-CU through different IAB host nodes-DU before and after the handover, which may specifically refer to the description of the embodiment of fig. 7 (a).

In step 702b, the first IAB node sends a second RRC message to the third IAB node when the first condition is satisfied. Accordingly, the second IAB node receives the second RRC message.

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.

The second RRC message includes second configuration information for transport network layer migration between the third IAB node and the IAB host node-CU.

The third IAB node may begin performing transport network layer migration after receiving the second RRC message.

According to the above scheme, after receiving the first RRC message from the second IAB node, the first IAB node may start to perform transport network layer migration on the one hand, and immediately send the second RRC message to the child node of the first IAB node on the other hand, so as to trigger the child node of the first IAB node to start to perform transport network layer migration as early as possible, which may avoid that the child node of the first IAB node performs transport network layer migration too late, which may cause an excessively long service interruption delay of the UE, thereby reducing an impact on the service delay of the UE served by the IAB node, and may improve communication efficiency.

As an implementation method, on the basis that the first condition includes the condition 1), the first condition further includes the following condition 2):

condition 2): the first IAB node does not receive the first information from the second IAB node.

The first information is used for data transmission after the first IAB node is switched, where the data transmission may be data transmission of a user plane or signaling transmission of a control plane.

The first information includes one or more of a BAP route mapping configuration, a BH RLC CH mapping configuration, or a BAP route identification configuration. Wherein, the meaning of the BAP route mapping configuration, the BH RLC CH mapping configuration, or the BAP route identification configuration may refer to the foregoing description.

If the first IAB node receives the first information from the second IAB node, the IAB host node-CU finishes the route updating of the IAB network and obtains the first information. Therefore, with the condition 2), it is limited that the first IAB node sends the second RRC message to the third IAB node before receiving the first message from the second IAB node, so that the third IAB node can start to perform transport network layer migration as early as possible, and it can avoid that the service interruption delay of the UE is too long due to the too-late execution of the transport network layer migration by the third IAB node, thereby reducing the influence of the service delay on the UE served by the IAB node, and improving the communication efficiency.

condition 3): the first IAB node does not complete transport network layer migration between the first IAB node and the IAB host node-CU according to the first configuration information.

Through the condition 3), it is avoided that the first IAB node starts sending the second RRC message to the third IAB node after completing the transport network layer migration, so that it is avoided that the service interruption delay of the UE is too long due to the third IAB node performing the transport network layer migration too late, thereby reducing the service delay impact on the UE served by the IAB node, and improving the communication efficiency.

In order to implement that a subordinate node of a migrating IAB node is instructed to execute transport network layer migration at a proper time, the embodiment of the present application provides a communication method, where the method corresponds to the second implementation method, and the method provides a first condition that needs to be met when the migrating IAB node sends an RRC message to a child node of the migrating IAB node in the second implementation method.

Referring to fig. 8 (a), the method includes the steps of:

step 801a is the same as step 701a described above.

Step 802a, after meeting the first condition, the first IAB node sends indication information to the second IAB node. Accordingly, the second IAB node receives the indication information.

The indication information is used to trigger validation of a second RRC message in the second IAB node, the second RRC message including second configuration information used for transport network layer migration of the second IAB node. The second RRC message may also be referred to as an RRC message of the second IAB node.

Wherein, the second IAB node may receive the second RRC message from the IAB host node-CU and store it locally before step 801 a. Then, after receiving the indication information from the first IAB node, the second IAB node validates the second RRC message according to the indication information. I.e. the second IAB node, may start to perform transport network layer migration after receiving the indication information. Taking fig. 5 or fig. 6 as an example, after the IAB node 2 receives the indication information for triggering the RRC message of the IAB node 2 to take effect from the IAB node 1, the transport network layer migration is started according to the RRC message of the IAB node 2.

The beneficial effects of the above scheme can refer to the beneficial effects of the embodiment of fig. 7 (a), and are not described again.

As an implementation method, on the basis that the first condition includes the above condition 1) and condition 2), the embodiment of fig. 7 (a) may further include condition 3) and/or condition 4), and for specific description, reference may be made to description of the embodiment of fig. 7 (a), which is not described again.

In order to implement that the subordinate node of the migration IAB node is instructed to execute transport network layer migration at a proper time, the embodiment of the present application provides a communication method, which corresponds to the second implementation method, and provides a first condition that needs to be satisfied when the subordinate node of the migration IAB node sends an RRC message to a child node of the subordinate node in the second implementation method.

Referring to fig. 8 (b), the method includes the steps of:

in step 801b, the first IAB node determines that a first condition is satisfied.

The first condition includes:

condition 1): the first IAB node receives the first indication information from the second IAB node.

The first indication information is used to trigger the first RRC message in the first IAB node to take effect.

The meaning of the first RRC message may refer to the description of the embodiment of fig. 7 (b).

Step 802b, when the first condition is satisfied, the first IAB node sends a second indication message to the third IAB node. Accordingly, the third IAB node receives the second indication information.

The second indication information is used to trigger validation of a second RRC message in the third IAB node.

The meaning of the second RRC message may refer to the description of the embodiment of fig. 7 (b).

And the third IAB node starts to execute the transport network layer migration according to the stored second RRC message after receiving the second indication information.

According to the above solution, after receiving the first indication information from the second IAB node, the first IAB node may start to perform transport network layer migration on the one hand, and immediately send the second indication information to the child node of the first IAB node on the other hand, so as to trigger the child node of the first IAB node to start to perform transport network layer migration as early as possible, which may avoid that the child node of the first IAB node performs transport network layer migration too late and causes an excessively long service interruption delay of the UE, thereby reducing the service delay impact on the UE served by the IAB node, and may improve communication efficiency.

As an implementation method, on the basis that the first condition includes the above condition 1), the embodiment of fig. 7 (b) may further include condition 2) and/or condition 3), and the detailed description may refer to the description of the embodiment of fig. 7 (b), which is not described again.

In the embodiments of fig. 7 (a), 7 (b), 8 (a) and 8 (b), the action of the first IAB node "determining that the first condition is satisfied" may be executed or may not be executed. When the action is not performed, it can be understood that after the first condition is satisfied, the first IAB node may perform a subsequent operation, such as performing step 702a, step 702b, step 802a, or step 802b.

The embodiments of fig. 7 (a), 7 (b), 8 (a) and 8 (b) may be implemented individually or in combination. Such as the embodiment of fig. 7 (a) and 7 (b) described above, further such as the embodiment of fig. 8 (a) and 8 (b) described above, further such as the embodiment of fig. 7 (a) and 8 (b) described above, further such as the embodiment of fig. 8 (a) and 7 (b) described above.

In a scenario where an IAB node is handed over, which causes the transport layer migration to be completed by the migration IAB node and the subordinate nodes of the migration IAB node, how to disable the source path (i.e., the old transport path) and how to disable the transport layer migration on the target path (i.e., the new transport path) before the transport layer migration is completed by the migration IAB node and the subordinate nodes of the migration IAB node after the IAB node completes the handover, are not yet completed, and thus the target path is temporarily disabled.

To solve the problem, embodiments of the present application further provide a corresponding data transmission method, and the following data transmission method may be combined with one or more of the embodiments of fig. 7 (a), fig. 7 (b), fig. 8 (a), or fig. 8 (b) described above, or may also be implemented separately.

The following data transmission method can be applied to a topology update scenario in an IAB network host or a topology update scenario in which the IAB network is across hosts. The method includes that a migration IAB node is switched from a source father node to a target father node, after the migration IAB node is switched to the target father node, before the migration of a transmission network layer between the migration IAB node and a subordinate IAB node of the migration IAB node and an IAB host node-CU is completed, each IAB node on a target path can not use a source path to transmit data any more, and can not use the target path to transmit data directly.

For example, referring to fig. 5, the migrating IAB node is IAB node 1, and before IAB node 1 switches from access IAB node 5 to access 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, IAB host node-CU. After IAB node 1 is handed over from access IAB node 5 to access IAB node 6, some or all of the following nodes are included on the target path: UEIAB node 4, IAB node 3, IAB node 1, IAB node 6, IAB host-DU 2, IAB host node-CU. After the IAB node 1 is switched to access the IAB node 6, the migration IAB node and the subordinate IAB nodes on the target path, such as IIAB node 3 and IAB node 4, of the migration IAB node need to complete the transport network layer migration with the IAB host node-CU. Therefore, before the transport network layer migration between the IAB node 1, the IAB node 3, and the IAB node 4 and the IAB host node-CU is completed, neither the source path nor the target path can be used normally, and at this time, the following data transmission method provided in the embodiment of the present application may be used.

The uplink data packet or the downlink data packet described in the following embodiments may be a service data packet or a data packet transferred by a transport network layer. When the upstream or downstream packet is a packet migrated in the transport network layer, the upstream or downstream packet may be various data blocks (CHUNK) of the SCTP layer, such as SCTP INIT CHUNK, or a message related to the IPsec security negotiation process (e.g., IKEv2 related message), or an F1AP message, such as F1 SETUP REQUEST message, GNB-DU CONFIGURATION UPDATE message, and the like, involved in the connection establishment process.

Next, a data transmission method of the migration IAB node and subordinate nodes of the migration IAB node in different scenarios is described.

1. Data transmission method for migrating IAB (inter-Access Point B) node

The migrating IAB node is hereinafter represented by the first IAB node, which is, for example, IAB node 1 in fig. 5 or fig. 6. And, the first IAB node has received a first RRC message from the IAB host node-CU before receiving the uplink data packet or the downlink data packet, the first RRC message including the first configuration information.

For uplink transmission, the first configuration information includes a first BAP route identifier, and the first BAP route identifier is used for the first IAB node to perform uplink data transmission on a target path. Here, the first BAP routing identity may also be referred to as a default BAP routing identity. Optionally, the first configuration information may further include an identifier of a BH RLC CH between the first IAB node and a next hop node of the first IAB node in uplink transmission, where the identifier of the BH RLC CH is used to identify the BH RLC CH between the first IAB node and the next hop node of the first IAB node in uplink transmission, and the next hop node of the first IAB node may be a target parent node of the first IAB node. Here, the identity of the BH RLC CH may also be referred to as the identity of the default BH RLC CH. The BH RLC CH between the first IAB node and the next hop node of the first IAB node in uplink transmission may also be referred to as a BH RLC CH between the first IAB node and a parent node of the first IAB node.

For downlink transmission, the first configuration information may further include an identifier of a BH RLC CH between the first IAB node and its child node, where the BH RLC CH is a default BH RLC CH between the first IAB node and its child node. When the first IAB node needs to send a downlink BAP Protocol Data Unit (PDU) to its child node but cannot find a mapping relation that can match with the BAP PDU based on the current configuration, the first IAB node may map the BAP PDU onto the BH RLC CH and send the BAP PDU to the child node. In a possible implementation manner, the identity of the BH RLC CH may be determined by the identity of a child node of the first IAB node (e.g., the BAP address of the child node) and the BH RLC CH ID of the BH RLC CH. The BH RLC CH between the first IAB node and the child node of the first IAB node may also be referred to as a BH RLC CH between the first IAB node and a next hop node of downlink transmission of the first IAB node.

In another possible implementation manner, the identity of the BH RLC CH between the first IAB node and its child node is not configured through the first configuration information, but is sent to the first IAB node by the IAB host node-CU through an F1AP message, where the F1AP message may be sent to the first IAB node before the IAB host node-CU sends the first RRC message to the first IAB node, or may be sent to the first IAB node by the IAB host node-CU after the first IAB node switches to connect to the target parent node according to the first RRC message. For example, in the F1AP message, configuration information of one or more BH RLC CHs between the first IAB node and one or more child nodes of the first IAB node is carried, the configuration information including an identification of the BH RLC CH between the first IAB node and the child nodes of the first IAB node. Optionally, the configuration information may further include indication information, where the indication information is used to indicate a default BH RLC CH in the configuration information. For example, the first IAB node has 2 child nodes, i.e., an IAB node a and an IAB node b, 2 BH RLC CHs are respectively between the first IAB node and the IAB node a, and 3 BH RLC CHs are respectively between the first IAB node and the IAB node b, i.e., 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, where the configuration information 1 includes an identifier of a BH RLC CH a and an identifier of a BH RLC CH b between the first IAB node and the IAB node a, and also includes indication information for indicating that the BH RLC CH b indicated by the identifier of the BH RLC CH b is a default BH RLC CH between the first IAB node and the IAB node a, and the configuration information 2 includes an identifier of a BH RLC CH c between the first IAB node and the IAB node b, an identifier of a BH RLC CH d, and an identifier of a BH RLC CH e, and also includes indication information for indicating that the BH RLC CH c indicated by the identifier of the BH RLC CH c is the default BH RLC CH between the first IAB node and the IAB node b. In a specific implementation, the configuration information 1 and the configuration information 2 may be carried in different F1AP messages and sent to the first IAB node, or the configuration information 1 and the configuration information 2 may also be combined into one configuration information, and the configuration information may be carried in one F1AP message and sent to the first IAB node.

Optionally, the first configuration information further includes a new IP address allocated to the first IAB node, where the new IP address may be used for transmission of data or signaling on a new transmission path by the first IAB node, for example, for transport network layer migration of the first IAB node.

The following respectively introduces a data transmission method in a topology update scenario of the migration IAB node in the IAB network host and a topology update scenario of the IAB network cross-host.

1. Data transmission method executed by migrating IAB (inter-integrated access node) under topology updating scene in IAB network host

In a topology updating scene of the migration IAB node in the IAB network host, a source father node and a target father node of the migration IAB node are connected to different IAB host nodes-DUs, and the different IAB host nodes-DUs respectively establish an F1 interface with the IAB host node-CU, or the different IAB host nodes-DUs are understood to belong to the same IAB host node-CU, or the different IAB host nodes-DUs are understood to be managed by the same IAB host node-CU. Taking fig. 5 as an example, the source father node of the IAB node 1 is connected to the IAB hosting node-DU 1, the target father node of the IAB node 1 is connected to the IAB hosting node-DU 2, the IAB hosting node-DU 1 and the IAB hosting node-DU 2 belong to the same IAB hosting node-CU.

The following is divided into an uplink direction and a downlink direction, and a data transmission method executed by the migration IAB node in a topology update scenario in the IAB network host is respectively introduced.

1) In the upstream direction

Referring to fig. 9, a schematic flow chart of a data transmission method according to an embodiment of the present application is shown, where the method introduces a processing method after the migration IAB node receives an uplink data packet.

The method comprises the following steps:

in step 901, the first IAB node receives an uplink data packet.

Specifically, the first IAB node receives an uplink data packet from a child node of the first IAB node, where the uplink data packet may be generated by a subordinate node of the first IAB node, such as generated by the IAB node 2, the IAB node 3, or the IAB node 4 in fig. 5, or the uplink data packet may also be generated by the UE, and the application does not limit a generation manner of the uplink data packet.

The uplink data packet includes a second BAP route identifier, the second BAP route identifier is added to the uplink data packet by the IAB node generating the uplink data packet according to the configuration information received from the IAB host node-CU, and the second BAP route identifier is used for data transmission of the IAB node on the target path.

Step 902, 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.

According to the above solution, after the migrating IAB node (i.e. the first IAB node) is handed over to the target parent node and before the transport network layer migration between the migrating IAB node (i.e. the first IAB node) and the IAB host node-CU is completed, after the first IAB node receives the uplink packet, if the BAP address in the uplink packet is the same as the BAP address in the first BAP routing identifier, the first IAB node may use the first BAP routing identifier to route the uplink packet. Therefore, the received uplink data packet can be ensured to be successfully sent, and the packet loss is avoided. And, can also realize the transmission of the up run data packet as early as possible, reduce the business of UE and interrupt the time delay.

As an implementation method, the step 902 specifically includes: and 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 does not receive the first information from the IAB host node-CU, the first IAB node sends an uplink data packet according to the first BAP routing identifier. The first information is used for data transmission after the first IAB node is switched, and the first information comprises one or more of BAP route mapping configuration, BH RLC CH mapping configuration or BAP route identification configuration. The specific meanings of the BAP routing mapping configuration, the BH RLC CH mapping configuration, and the BAP routing identification configuration can be referred to the foregoing description. According to the scheme, before the BAP routing configuration information is received on the target path, the routing of the data packet can not be performed according to the BAP routing configuration information on the target path, but the method can be used, and the first IAB node uses the first BAP routing identifier of the first IAB node to route the received uplink data packet, so that the received uplink data packet can be ensured to be successfully sent, and the occurrence of packet loss is avoided.

As an implementation method, the first IAB node sends the uplink data packet according to the first BAP routing identifier, which may specifically be: and the first IAB node determines a next hop node of the first IAB node corresponding to the first BAP routing identifier, and then the first IAB node sends the uplink data packet to the next hop node. The next hop node of the first IAB node corresponding to the first BAP route identifier may be a default parent node of the first IAB node, for example, the default parent node may be a target parent node of the first IAB node. Or the first configuration information further includes an identifier of a next hop node corresponding to the first BAP route identifier, and the next hop node of the first IAB node corresponding to the first BAP route identifier is a node indicated by the identifier of the next hop node. Optionally, the first configuration information further includes an identifier of a BH RLC CH, where the identifier of the BH RLC CH may be used to indicate a default BH RLC CH between the first IAB node and its default parent node, and therefore, the first IAB node may send the uplink packet to a next-hop node of the first IAB node on the BH RLC CH indicated by the identifier of the BH RLC CH.

Referring to fig. 10, a flowchart of a data transmission method according to an embodiment of the present application is shown, where the method introduces a sending method after an migrating IAB node generates an uplink data packet.

The method comprises the following steps:

step 1001, the first IAB node generates an uplink data packet.

The first IAB node herein refers to the migrating IAB node, such as IAB node 1 in fig. 5. And the first IAB node has received a first RRC message from the IAB donor node-CU before generating the uplink data packet, where the first RRC message includes first configuration information, and the first configuration information includes a first BAP route identifier, and the first BAP route identifier is used for data transmission by the first IAB node on the target path.

The generated uplink data packet includes a first BAP routing identifier.

In step 1002, the first IAB node determines a next hop node of the first IAB node corresponding to the first BAP route identifier.

The first IAB node determines the next hop node of the first IAB node corresponding to the first BAP routing identifier, which may refer to the description in the embodiment of fig. 9 and is not described again.

Step 1003, the first IAB node sends the uplink data packet to the next hop node.

The first IAB node may refer to the description in the embodiment of fig. 9 for sending the uplink data packet to the next hop node, which is not described again.

According to the scheme, after the migration IAB node is switched to the target father node and before the migration of the transmission network layer between the migration IAB node and the IAB host node-CU is completed, the first IAB node generates an uplink data packet and then uses the first BAP routing identifier to route the uplink data packet. Therefore, the received uplink data packet can be ensured to be successfully sent, and the packet loss is avoided. And moreover, the transmission of the uplink data packet can be performed as early as possible, and the service interruption time delay of the UE is reduced.

2) Down direction

Referring to fig. 11, a flowchart of a data transmission method according to an embodiment of the present application is shown, where the method introduces a processing method after the migration IAB node receives a downlink data packet.

The method comprises the following steps:

step 1101, the first IAB node receives a downlink data packet, where the downlink data packet includes the third BAP routing identifier.

The downlink data packet is generated by an upstream node of the first IAB node, for example, the IAB host node-DU 2 in fig. 5 adds a BAP layer header to the received downlink IP packet.

In the embodiment of the present application, the "upstream node of the first IAB node" includes a parent node of the first IAB node and nodes above the parent node, or is understood to be an IAB node on a transmission path between the IAB host node and the first IAB node. Specifically, the upstream node of the first IAB node includes a parent node, a grandparent node, a parent node of a grandparent node, a grandparent node of a grandparent node, and so on of the first IAB node. The description is unified here and will not be described in detail later.

The downlink data packet includes a third BAP route identifier, the third BAP route identifier is added to the downlink data packet by the IAB home node-DU node that generates the downlink data packet based on the configuration information received from the IAB home node-CU, and the third BAP route identifier is used for performing downlink data transmission on the target path.

Step 1102, the first IAB node determines that the first RRC message is received and the first IAB node does not receive the first information from the IAB donor node-CU, and determines a next hop node of the first IAB node according to the BAP address in the third BAP routing identifier.

That is, when the rerouting trigger condition is met, the first IAB node reroutes according to the BAP address in the third BAP routing identifier, and the rerouted node is the determined next hop node of the first IAB node. The rerouting trigger conditions are: the first IAB node determines that the first RRC message was received and that the first IAB node did not receive the first information from the IAB host node-CU.

The meaning of the first information herein refers to the foregoing description and is not repeated.

The first IAB node determines the next hop node of the first IAB node according to the BAP address in the third BAP routing identifier, which may specifically be: and the first IAB node searches the table item matched with the third BAP routing identification in the configured routing mapping table, and if the table item can be searched to be matched, the next hop node indicated by the next hop node identification in the table item is selected. If the entry matched with the third BAP routing identification cannot be found, the entry matched with the BAP address field in the third BAP routing identification is found, and then the next hop node indicated by the next hop node identification in the entry is determined as the next hop node for sending the downlink data packet. If the routing mapping table is searched to obtain a plurality of matching entries, that is, identifiers of a plurality of next hop nodes, based on the BAP address field in the third BAP routing identifier, the first IAB node may select one of the identifiers of the plurality of next hop nodes, or select the identifier of the next hop node corresponding to the entry with the highest priority according to the priority of each matching entry.

Step 1103, the first IAB node sends a downlink data packet to the next hop node.

According to the scheme, after the migration IAB node is switched to the target father node and before the transfer network layer between the migration IAB node and the IAB host node-CU is migrated, the first IAB node receives the downlink data packet and performs rerouting according to the BAP address in the third BAP routing identifier when the rerouting triggering condition is determined to be met. Therefore, the received downlink data packet can be ensured to be successfully sent, and the packet loss is avoided. And, can also realize the transmission of the downlink data packet as early as possible, reduce the business interruption time delay of UE.

2. Data transmission method executed by migrating IAB (inter-integrated access node) in cross-host topology updating scene of IAB (inter-integrated access node)

In a topology updating scene of an IAB network across hosts, a source father node and a target father node of the migration IAB node are connected to different IAB hosting nodes-DUs, and the different IAB hosting nodes-DUs respectively establish an F1 interface with different IAB hosting nodes-CUs, or understand that the different IAB hosting nodes-DUs belong to different IAB hosting nodes-CUs, or understand that the different IAB hosting nodes-DUs are managed by different IAB hosting nodes-CUs. The source parent node is connected to the source IAB host node-DU, the source IAB host node-DU is owned by the source IAB host node-CU, and the source IAB host node-DU and the source IAB host node-CU may be collectively referred to as a source IAB host node. The target parent node is connected to a target IAB host node-DU, the target IAB host node-DU is owned by a target IAB host node-CU, and the target IAB host node-DU and the target IAB host node-CU may be collectively referred to as a target IAB host node. For example, in FIG. 6, the source father node of the IAB node 1 is connected to the IAB home node DU 1, the target father node of the IAB node 1 is connected to the IAB home node DU 2, the IAB home node DU 1 belongs to the IAB home node CU1, and the IAB home node DU 2 belongs to the IAB home node CU 2. The following description is divided into an uplink direction and a downlink direction, and introduces a data transmission method executed by the migration IAB node in a topology update scenario between IAB network hosts (i.e., across IAB hosts), respectively.

1) In the upstream direction

Referring to fig. 12, a flowchart of a data transmission method according to an embodiment of the present application is shown, where the method introduces a processing method after the migration IAB node receives an uplink data packet.

The method comprises the following steps:

step 1201, the first IAB node receives the uplink data packet.

Specifically, the first IAB node receives an uplink data packet from a child node of the first IAB node, where the uplink data packet may be generated by a subordinate node of the first IAB node, such as generated by the IAB node 2, the IAB node 3, or the IAB node 4 in fig. 6, or the uplink data packet may also be generated by the UE, and the application does not limit a generation manner of the uplink data packet.

In step 1202, the first IAB node replaces the second BAP routing identifier in the uplink data packet with the first BAP routing identifier.

As an implementation method, 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 first IAB node, the first IAB node replaces the second BAP routing identifier in the uplink data packet with the first BAP routing identifier. The BAP address allocated by the source IAB donor node-CU to the first IAB node may be sent by the source IAB donor node-CU to the first IAB node via an RRC message before the MT part of the first IAB node is handed over to the target parent node.

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 for 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 home node-CU to the target IAB home node DU may be configured by the source IAB home node-CU to the first IAB node in advance through an F1AP message or an RRC message, or may be sent to the first IAB node by the target IAB home node-CU through an RRC message after the MT part of the first IAB node is switched to the target parent node.

Step 1203, the first IAB node sends an uplink data packet according to the first BAP routing identifier.

According to the scheme, after the migration IAB node is switched to the target father node and before the migration of the transport network layer between the migration IAB node and the IAB home node-CU is completed, after the first IAB node receives the 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 distributed to the target IAB home node-DU by the source IAB home node-CU, the fact that the first IAB node needs to replace the BAP routing identifier in the uplink data packet indicates that the first IAB node is needed, and then the first IAB node uses the first BAP routing identifier of the first IAB node to route the uplink data packet. Therefore, the received uplink data packet can be successfully sent, and the packet loss is avoided. And, can also realize the transmission of the up run data packet as early as possible, reduce the business of UE and interrupt the time delay.

As an implementation method, the step 1202 may specifically be: and 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 does not receive the first information from the target IAB host node-CU, the first IAB node sends the uplink data packet according to the first BAP routing identifier. Alternatively, the step 1202 may specifically be: and when the BAP address in the second BAP route identifier is the same as the BAP address distributed by the source IAB host node-CU to the target IAB host node-DU and the first IAB node does not receive the first information from the target IAB host node-CU, the first IAB node sends the uplink data packet according to the first BAP route identifier. Wherein the meaning of the first information may refer to the foregoing description. According to the scheme, before the BAP routing configuration information (i.e. the first information) is received on the target path, the routing of the data packet cannot be performed according to the BAP routing configuration information on the target path, but the method of the present application may be used, and the first IAB node uses its own first BAP routing identifier to route the received uplink data packet, so that the successful sending of the received uplink data packet can be ensured, and the occurrence of packet loss is avoided.

As an implementation method, the first IAB node sends the uplink data packet according to the first BAP routing identifier, which may specifically be: and the first IAB node determines a next hop node of the first IAB node corresponding to the first BAP routing identifier, and then the first IAB node sends the uplink data packet to the next hop node. Wherein, the next hop node of the first IAB node corresponding to the first BAP routing identifier may be a default parent node of the first IAB node. Or the first configuration information further includes an identifier of a next hop node, and the next hop node of the first IAB node corresponding to the first BAP routing identifier is a node indicated by the identifier of the next hop node. Optionally, the first configuration information further includes an identifier of a BH RLC CH, where the identifier of the BH RLC CH may be used to indicate a default BH RLC CH between the first IAB node and its default parent node, and therefore, the first IAB node may send the uplink packet to a next-hop node of the first IAB node on the BH RLC CH indicated by the identifier of the BH RLC CH.

2) Down direction

Referring to fig. 13, a flowchart of a data transmission method according to an embodiment of the present application is shown, where the method introduces a processing method after the migration IAB node receives a downlink data packet.

The method comprises the following steps:

in step 1301, the first IAB node receives a downlink data packet.

The downlink data packet is generated by an upstream node of the first IAB node, for example, the IAB host node-DU 2 in fig. 6 adds a BAP layer header to the received downlink IP packet.

The downlink data packet includes a third BAP route identifier, the third BAP route identifier is added to the downlink data packet by the IAB home node-DU that generates the downlink data packet according to the configuration information received from the target IAB home node-CU, and the third BAP route identifier is used for performing downlink data transmission on the target path.

As an implementation method, the BAP address in the third BAP routing identifier is a BAP address of the first IAB node on the target path, that is, the BAP address in the third BAP routing identifier is a BAP address allocated by the target IAB host-CU for the first IAB node. For example, referring to fig. 6, the BAP address in the third BAP routing identifier is the BAP address allocated by the IAB donor node 2-CU for the IAB node 1.

As another implementation method, the BAP address in the third BAP routing identifier is a BAP address allocated by the target IAB host-CU for a subordinate node of the first IAB node. And, the first IAB node may acquire the BAP address allocated by the target IAB host-CU for the subordinate node of the first IAB node from the source IAB host-CU or the target IAB host-CU in advance. For example, referring to fig. 6, the BAP address in the third BAP routing identity is the BAP address allocated by the IAB home node 2-CU for the IAB node 6.

In step 1302, the first IAB node replaces the third BAP routing identifier in the downlink data packet with a fourth BAP routing identifier.

The BAP address in the fourth BAP routing identity is the BAP address allocated by the source IAB host node-CU for the subordinate nodes of the first IAB node. For example, referring to fig. 6, the BAP address in the fourth BAP routing identifier is the BAP address allocated by the IAB donor node 1-CU for the IAB node 6.

As an implementation method, the first configuration information in the first RRC message received by the first IAB node further includes the fourth BAP routing identifier. Optionally, the fourth BAP routing identifier in the first configuration information has a corresponding relationship with the third BAP routing identifier.

As an alternative implementation of this step 1302, the first IAB node may still keep the third BAP routing id, and then add the fourth BAP routing id to the header of the downlink data packet.

Step 1303, the first IAB node determines that the first RRC message is received and the first IAB node does not receive the first information from the IAB donor node-CU (i.e., the target IAB donor node-CU), and determines a next hop node of the first IAB node according to the BAP address in the fourth BAP route identifier.

That is, when the rerouting trigger condition is met, the first IAB node reroutes according to the BAP address in the fourth BAP routing identifier, and the rerouted node is the determined next-hop node of the first IAB node. The rerouting trigger conditions are: the first IAB node determines that the first RRC message was received and that the first IAB node did not receive the first information from the IAB host node-CU.

In step 1304, the first IAB node sends a downlink packet to the next hop node.

According to the scheme, after the migration IAB node is switched to the target father node and before the migration of the transport network layer between the migration IAB node and the migration IAB node on the target path between the subordinate IAB node and the IAB host node-CU is completed, after the first IAB node receives the downlink data packet, when the rerouting triggering condition is determined to be met, rerouting is carried out according to the BAP address in the fourth BAP routing identifier. Therefore, the received downlink data packet can be successfully sent, and the packet loss is avoided.

2. Data transmission method of subordinate IAB node of migration IAB node

The subordinate node of the migrating IAB node is hereinafter denoted as the first IAB node, which may be, for example, IAB node 2 or IAB node 3 in fig. 5 or 6. And, the first IAB node has received a first RRC message from a parent node of the first IAB node (hereinafter, referred to as a second IAB node) or an IAB donor node-CU before receiving the uplink data packet or the downlink data packet, the first RRC message including the first configuration information.

The information carried in the first configuration information is similar to the information carried in the first configuration information received by the migrating IAB node, and reference may be made to the foregoing description.

Whether the topology update scenario in the host of the IAB network or the topology update scenario of the cross-host of the IAB network, in the uplink direction, the method for processing the received uplink data packet by the subordinate node of the migration IAB node is similar to the method for processing the received uplink data packet by the migration IAB node in the embodiment of fig. 9, and details are not repeated.

Whether the topology update scenario in the host of the IAB network or the topology update scenario of the cross-host of the IAB network, in the uplink direction, the method for processing the uplink data packet generated by the migration IAB node by the subordinate node of the migration IAB node is similar to the method for processing the uplink data packet generated by the migration IAB node in the embodiment of fig. 10, and details are not repeated.

Whether the topology update scenario in the host of the IAB network or the topology update scenario of the cross-host of the IAB network, in the uplink direction, the method for processing the received downlink data packet by the subordinate node of the migration IAB node is similar to the method for processing the received downlink data packet by the migration IAB node in the embodiment of fig. 11, and is not described again.

It is to be understood that, in order to implement the functions in the foregoing embodiments, the migration IAB node or a subordinate node of the migration IAB node includes a corresponding hardware structure and/or software module for performing each function. Those of skill in the art will readily appreciate that the various illustrative elements and method steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software driven hardware depends on the particular application scenario and design constraints imposed on the solution.

Fig. 14 and fig. 15 are schematic structural diagrams of a possible communication device provided in an embodiment of the present application. These communication devices can be used to implement the functions of the migrating IAB node or the subordinate nodes of the migrating IAB node in the above method embodiments, so that the beneficial effects of the above method embodiments can also be achieved. In this embodiment, the communication device may be the migration IAB node or a subordinate node of the migration IAB node in this embodiment, or may be a module (e.g., a chip) applied to the migration IAB node, or a module (e.g., a chip) applied to the subordinate node of the migration IAB node.

As shown in fig. 14, the communication apparatus 1400 includes a processing unit 1410 and a transceiving unit 1420. The communication apparatus 1400 is configured to implement the functions of the migrating IAB node or the subordinate nodes of the migrating IAB node in the foregoing method embodiments.

In the first embodiment, when the communication apparatus 1400 is used to implement the function of migrating IAB nodes in the above method embodiments: a processing unit 1410 configured to determine that a first condition is satisfied, the first condition comprising: the first IAB node receives a first RRC message from an IAB host 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. A transceiving unit 1420, configured to send, to the second IAB node, indication information for triggering validation of a second RRC message in the second IAB node when the first condition is satisfied. Alternatively, the first IAB node sends the second RRC message to the second IAB node when the first condition is satisfied. Wherein the first RRC message includes first configuration information for transport network layer migration between the first IAB node and the IAB-hosting CU, and the second RRC message includes second configuration information for transport network layer migration between the second IAB node and the IAB-hosting 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, and the first IAB node is connected to the IAB host CU through the different IAB host DUs before and after handover.

As a possible implementation method, the different IAB host DUs to which the source parent node and the target parent node are connected all belong to the IAB host CU, and the first configuration information includes the first BAP routing identifier. A transceiving unit 1420, configured to receive an uplink data packet, where the uplink data packet includes a second BAP routing identifier, and send the uplink data packet according to the first BAP routing identifier when a BAP address in the second BAP routing identifier is the same as a BAP address in the first BAP routing identifier.

As a possible implementation method, the transceiving unit 1420 is configured to send the uplink data packet according to the first 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 and the first information is not received from the IAB host CU. The first information is used for data transmission after the first IAB node is switched, and the first information includes one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

As a possible implementation method, the IAB host DU connected to the source parent node belongs to the IAB host CU, the IAB host DU connected to the target parent node belongs to another IAB host CU different from the IAB host CU, and the first configuration information includes the first BAP route identifier. A transceiving unit 1420, configured to receive an uplink data packet, where the uplink data packet includes the second BAP routing identifier. A processing unit 1410, 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 for the first IAB node. A transceiving unit 1420, configured to send the uplink data packet according to the first BAP routing identifier.

As a possible implementation method, the transceiving unit 1420 is configured to, 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 information is not received from the IAB host CU, send the uplink data packet by the first IAB node according to the first BAP routing identifier. The first information is used for data transmission after the first IAB node is switched, and the first information includes one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

As a possible implementation method, the first configuration information further includes an identifier of the BH RLC CH. Processing unit 1410, configured to determine a next-hop node of the first IAB node corresponding to the first BAP route identifier. A transceiving unit 1420, configured to send the uplink data packet to the next hop node on the BH RLC CH.

As a possible implementation method, 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 transceiver unit 1420 is configured to receive a downlink data packet, where the downlink data packet includes the third BAP routing identifier. Processing unit 1410, configured to determine that the first RRC message is received and the first IAB node does not receive the first information from the IAB host CU, and determine a next hop node of the first IAB node according to the BAP address in the third BAP routing identifier. A transceiving unit 1420, configured 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 BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

As a possible implementation method, the IAB host DU connected to the source parent node belongs to the IAB host CU, the IAB host DU connected to the target parent node belongs to another IAB host CU different from the IAB host CU, and the first configuration information includes the fourth BAP route identifier. A transceiving unit 1420, configured to receive a downlink data packet, where the downlink data packet includes a third BAP routing identifier, and a BAP address in the third BAP routing identifier is a BAP address of the first IAB node. A processing unit 1410, configured to replace the third BAP routing identifier in the downlink data packet with the fourth BAP routing identifier. And the first IAB node determines that the first RRC message is received and the first IAB node does not receive the first information from the IAB host CU, and determines a next hop node of the first IAB node according to the BAP address in the fourth BAP routing identifier. A transceiving unit 1420, configured 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 BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

As a possible implementation method, the first configuration information includes a first BAP routing identifier. Processing unit 1410, configured to determine a next hop node of the first IAB node corresponding to the first BAP route identifier. A transceiving unit 1420, configured to send an uplink data packet to the next hop node, where the uplink data packet includes the first BAP routing identifier.

In the second embodiment, when the communication device 1400 is used to implement the function of migrating the subordinate nodes of the IAB node in the above method embodiment: a processing unit 1410 configured to determine that a first condition is satisfied, the first condition comprising: the first IAB node receives a first indication message or a first RRC message from a second IAB node, the second IAB node being a parent node of the first IAB node, the first indication message being used to trigger the first RRC message in the first IAB node to take effect. A transceiving unit 1420, configured to send second indication information to the third IAB node when the first condition is satisfied, where the second indication information is used to trigger a second RRC message in the third IAB node to take effect. Or, the transceiving unit 1420 is configured to send the second RRC message to the third IAB node when the first condition is satisfied, where the third IAB node is a child node of the first 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, the second RRC message includes second configuration information used for transport network layer migration between the third IAB node and the IAB host CU, and the first IAB node is connected to the IAB host CU through different IAB host DUs before and after transport network layer migration.

As a possible implementation method, the first configuration information includes a first BAP routing identifier. A transceiving unit 1420, configured to receive an uplink data packet, where the uplink data packet includes a second BAP routing identifier, and send the uplink data packet according to the first BAP routing identifier when a BAP address in the second BAP routing identifier is the same as a BAP address in the first BAP routing identifier.

As a possible implementation method, 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 does not receive the first information from the second IAB node, the transceiving unit 1420 is configured to send the uplink data packet according to the first BAP routing identifier. The first information is used for data transmission after the first IAB node is switched, and the first information includes one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

As a possible implementation method, the transceiving unit 1420 is configured to receive a downlink data packet, where the downlink data packet includes the third BAP routing identifier. Processing unit 1410, configured to determine that the first RRC message is received and the first IAB node does not receive the first information from the IAB host CU, and determine a next hop node of the first IAB node according to the BAP address in the third BAP routing identifier. A transceiving unit 1420, configured 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 BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

The more detailed description of the processing unit 1410 and the transceiving unit 1420 can be directly obtained by referring to the related description in the foregoing method embodiments, and details are not repeated herein.

As shown in fig. 15, the communications device 1500 includes a processor 1510 and interface circuits 1520. Processor 1510 and interface circuits 1520 are coupled to each other. It is understood that the interface circuit 1520 may be a transceiver or an input-output interface. Optionally, the communication device 1500 may further include a memory 1530 for storing instructions executed by the processor 1510 or for storing input data required by the processor 1510 to execute the instructions or for storing data generated by the processor 1510 after executing the instructions.

When the communication apparatus 1500 is configured to implement the foregoing method embodiments, the processor 1510 is configured to implement the functions of the processing unit 1410, and the interface circuit 1520 is configured to implement the functions of the transceiving unit 1420.

When the communication device is a module applied to an IAB node, the module implements the functions of the IAB node in the above method embodiments. The module receives information from other modules (such as radio frequency modules or antennas) in the IAB node, the information being sent to the IAB node by a terminal or other IAB nodes; alternatively, the module sends information to other modules (e.g., radio frequency modules or antennas) in the IAB node, which the IAB node sends to the terminal or other IAB nodes. The module may be a baseband chip of the IAB node, or may be a CU, DU, or other module.

It is understood that the Processor in the embodiments of the present Application may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The general purpose processor may be a microprocessor, but may be any conventional processor.

The method steps in the embodiments of the present application may be implemented by hardware, or may be implemented by software instructions executed by a processor. The software instructions may be comprised of corresponding software modules, which may 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, a hard disk, a removable hard disk, a compact disk read-only memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be integral to the processor. The processor and the storage medium may reside in an ASIC. In addition, the ASIC may be located in the migrating IAB node or a subordinate node of the migrating IAB node. Of course, the processor and the storage medium may reside as discrete components in the migrating IAB node or in a subordinate node to the migrating IAB node.

In the above embodiments, all or part of the implementation may be realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part 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 the present application are performed in whole or in part. The computer may 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 may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer program or instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire or wirelessly. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that integrates one or more available media. The usable medium may be a magnetic medium, such as a floppy disk, hard disk, magnetic tape; optical media such as digital video disks; but may also be a semiconductor medium such as a solid state disk. The computer readable storage medium may be volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

In the embodiments of the present application, unless otherwise specified or conflicting with respect to logic, the terms and/or descriptions in different embodiments have consistency and may be mutually cited, and technical features in different embodiments may be combined to form a new embodiment according to their inherent logic relationship.

In the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" describes the association relationship of the associated object, indicating that there may be three relationships, for example, a and/or B, which may indicate: a exists alone, A and B exist simultaneously, and B exists alone, wherein A and B can be singular or plural. In the description of the text of the present application, the character "/" generally indicates that the former and latter associated objects are in an "or" relationship; in the formula of the present application, the character "/" indicates that the preceding and following associated objects are in a "division" relationship.

It is to be understood that the various numerical references referred to in the embodiments of the present application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of the present application. The sequence numbers of the above processes do not mean the execution sequence, and the execution sequence of the processes should be determined by the functions and the inherent logic.

Claims

1. A method of communication, comprising:

the first access backhaul integrated IAB node determines that a first condition is satisfied, where the first condition includes: the first IAB node receives a first Radio Resource Control (RRC) message from an IAB host Centralized Unit (CU), and the first IAB node is switched 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;

when the first condition is met, the first IAB node sends indication information to a second IAB node, wherein the indication information is used for triggering a second RRC message in the second IAB node to take effect; or, when the first condition is satisfied, the first IAB node sends the second RRC message to the second IAB node;

wherein the first RRC message comprises first configuration information for transport network layer migration between the first IAB node and the IAB anchor CU, and the second RRC message comprises second configuration information for transport network layer migration between the second IAB node and the IAB anchor CU; the second IAB node is a child node of the first IAB node, the source father node and the target father node are connected to different IAB-hosted distributed units DU, and the first IAB node is connected to the IAB-hosted CU through the different IAB-hosted DUs before and after the handover.

2. The method of claim 1, wherein the first condition further comprises:

the first IAB node does not receive first information from the IAB host CU, the first information being used for data transmission after the first IAB node is handed over, the first information including one or more of a backhaul adaptation protocol, BAP, route mapping configuration, a backhaul radio link control channel, BH, RLC, CH, mapping configuration, or BAP route identification configuration.

3. The method of claim 1 or 2, wherein the first condition further comprises:

the first IAB node does not complete transport network layer migration between the first IAB node and the IAB host CU according to the first configuration information.

4. The method of claim 1, wherein different IAB host DUs to which the source parent node and the target parent node are connected are both owned by the IAB host CU, the first configuration information comprising a first BAP route identification;

the method further comprises the following steps:

the first IAB node receives an uplink data packet, wherein the uplink data packet comprises a second BAP routing identifier;

and 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.

5. The method of claim 4, wherein 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 sending the uplink packet according to the first BAP routing identifier comprises:

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 does not receive first information from the IAB host CU, the first IAB node sends the uplink data packet according to the first BAP routing identifier;

the first information is used for data transmission after the first IAB node is switched, and the first information includes one or more of BAP route mapping configuration, BH RLC CH mapping configuration, or BAP route identifier configuration.

6. The method of claim 1, wherein the IAB host DU for the source parent node connection is owned by the IAB host CU, wherein the IAB host DU for the target parent node connection is owned by another IAB host CU different from the IAB host CU, and wherein the first configuration information comprises a first BAP route identification;

the method further comprises the following steps:

when the BAP address in the second BAP route identifier is the same as the BAP address distributed by the IAB host CU to the first IAB node, the first IAB node replaces the second BAP route identifier in the downlink data packet with the first BAP route identifier;

and the first IAB node sends the uplink data packet according to the first BAP routing identifier.

7. The method of claim 6, wherein when the BAP address in the second BAP routing identifier is the same as the BAP address of the first IAB node, the first IAB node sending the uplink packet according to the first BAP routing identifier comprises:

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 does not receive the first information from the IAB host CU, the first IAB node sends the uplink data packet according to the first BAP route identifier;

8. The method of any of claims 4 to 7, wherein the first configuration information further comprises an identification of a BH RLC CH;

the sending, by the first IAB node, the uplink data packet according to the first BAP routing identifier includes:

the first IAB node determines a next hop node of the first IAB node corresponding to the first BAP routing identifier;

and the first IAB node sends the uplink data packet to the next hop node on the BH RLC CH.

9. The method of claim 8,

the next hop node is a default parent node of the first IAB node; or,

the first configuration information further includes an identifier of the next hop node.

10. The method of claim 1, wherein different IAB-hosting DUs to which the source parent node and the target parent node are connected are both owned by the IAB-hosting CU, the method further comprising:

the first IAB node receives a downlink data packet, wherein the downlink data packet comprises a third BAP routing identifier;

the first IAB node determines that the first RRC message is received and the first IAB node does not receive the first information from the IAB host CU, and determines a next hop node of the first IAB node according to a BAP address in the third BAP routing identifier;

the first IAB node sends the downlink data packet to the next hop node;

11. The method of claim 1, wherein the IAB host DU for the source parent node connection is owned by the IAB host CU, wherein the IAB host DU for the target parent node connection is owned by another IAB host CU different from the IAB host CU, and wherein the first configuration information comprises a fourth BAP route identification;

the method further comprises the following steps:

the first IAB node receives a downlink data packet, wherein the downlink data packet comprises a third BAP routing identifier, and a BAP address in the third BAP routing identifier is the BAP address of the first IAB node;

replacing the third BAP routing identifier in the downlink data packet with the fourth BAP routing identifier by the first IAB node;

the first IAB node determines that the first RRC message is received and the first IAB node does not receive the first information from the IAB host CU, and determines a next hop node of the first IAB node according to a BAP address in the fourth BAP routing identifier;

the first IAB node sends the downlink data packet to the next hop node;

12. The method of any of claims 1 to 11, wherein the first configuration information comprises a new internet protocol, IP, address allocated for the first IAB node.

13. A method of communication, comprising:

the first access backhaul integrated IAB node determines that a first condition is satisfied, where the first condition includes: the first IAB node receives first indication information or a first Radio Resource Control (RRC) message from a second IAB node, wherein the second IAB node is a parent node of the first IAB node, and the first indication information is used for triggering the first RRC message in the first IAB node to take effect;

when the first condition is met, the first IAB node sends second indication information to a third IAB node, wherein the second indication information is used for triggering a second RRC message in the third IAB node to take effect; or, when the first condition is satisfied, the first IAB node sends the second RRC message to a third IAB node, which is a child node of the first IAB node;

wherein the first RRC message includes first configuration information used for transport network layer migration between the first IAB node and an IAB-hosting centralized unit CU, the second RRC message includes second configuration information used for transport network layer migration between the third IAB node and the IAB-hosting CU, and the first IAB node is connected to the IAB-hosting CU through different IAB-hosting distributed units DU before and after transport network layer migration.

14. The method of claim 13, wherein the first condition further comprises:

the first IAB node does not receive first information from the second IAB node, the first information is used for data transmission after the first IAB node migrates in a transport network layer, and the first information includes one or more of a Backhaul Adaptation Protocol (BAP) routing mapping configuration, a backhaul radio link control channel (BH RLC CH) mapping configuration, or a BAP routing identification configuration.

15. The method of claim 13 or 14, wherein the first condition further comprises:

16. The method of claim 13, wherein the first configuration information includes a first BAP routing identification;

the method further comprises the following steps:

17. The method of claim 16, wherein when the BAP address in the second BAP routing identity is the same as the BAP address in the first BAP routing identity, the first IAB node sending the uplink packet according to the first BAP routing identity, comprising:

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 does not receive the first information from the second IAB node, the first IAB node sends the uplink data packet according to the first BAP routing identifier;

18. The method of claim 16 or 17, wherein the first configuration information further comprises an identification of a BH RLC CH;

the first IAB node sending the uplink data packet according to the first BAP route identifier includes:

19. The method of claim 18,

the next hop node is a default parent node of the first IAB node; or,

20. The method of claim 13, wherein the method further comprises:

the first IAB node determines to receive the first RRC message and does not receive the first information from the IAB host CU, and determines a next hop node of the first IAB node according to the BAP address in the third BAP routing identifier;

the first IAB node sends the downlink data packet to the next hop node;

21. The method of any of claims 13 to 20, wherein the first configuration information comprises a new internet protocol, IP, address assigned for the first IAB node.

22. A communications device comprising means for performing a method as claimed in any one of claims 1 to 12, or means for performing a method as claimed in any one of claims 13 to 21.

23. A communications device comprising a processor and interface circuitry for receiving and transmitting signals to or from a communications device other than the communications device, the processor being configured to implement the method of any of claims 1 to 12 or to implement the method of any of claims 13 to 21 by logic circuitry or executing code instructions.

24. A computer-readable storage medium, in which a computer program or instructions is stored which, when executed by a communication apparatus, carries out the method of any one of claims 1 to 21.