A communication method and device

Abstract

A communication method and device, the method comprising: a first IAB node receives a first message from a CU of an IAB host, the first message is used to instruct the first IAB node to switch from a first parent node to a second parent node, and the first message includes a first IP address of the first IAB node. The first IAB node determines the first transmission network layer coupling information between the first IAB node and the CU of the IAB host based on the first IP address, and the first IAB node updates the context information of the control plane of the F1 interface with the first transmission network layer coupling information, and the F1 interface is the interface between the first IAB node and the CU of the IAB host. By using the method and device of the present application, the IAB node can communicate with the CU of the IAB host as soon as possible using the first IP address after the switching is completed, thereby reducing the delay impact on the terminal device business served by the IAB node.

Description

Technical Field

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

[0002] The fifth-generation (5G) mobile communication system introduces the integrated access and backhaul (IAB) network technology. The access link and backhaul link in the IAB network both use wireless transmission solutions to avoid optical fiber deployment, thereby reducing deployment costs and improving deployment flexibility. In the IAB network, the IAB donor gNodeB (IAB DgNB) is connected to the core network (for example, the core network (5G core, 5GC) in the 5G system) through a wired link, and then an integrated access and backhaul node (IAB node) is added between the IAB donor gNodeB and the terminal. The access link (AL) of the IAB node provides wireless access services to the terminal, and the backhaul link (BL) of the IAB node is connected to the IAB donor gNodeB to transmit the service data of the terminal.

[0003] Currently, when the IAB network topology is updated, if the IAB host base station to which the IAB node is connected changes, the F1 interface will be rebuilt. Since the F1 interface is rebuilt, the control plane / user plane context of the F1 interface must be regenerated, which has a significant impact on the latency of terminal services and brings a lot of signaling overhead. Summary of the invention

[0004] The present application provides a communication method and device for improving the problems of large service delay and large signaling overhead caused by F1 interface reconstruction.

[0005] In a first aspect, the present application provides a communication method, which is applicable to a scenario in which a first IAB node switches from a first DU of an IAB host to a second DU of an IAB host within the service range of a CU of the same IAB host. The method includes: the first IAB node receives a first message from the CU of the IAB host, the first message is used to indicate that the first IAB node switches from a first parent node to a second parent node, wherein the first parent node is the first DU of the IAB host, or the first parent node is connected to the CU of the IAB host through the first DU of the IAB host. The second parent node is the second DU of the IAB host, or the second parent node is connected to the CU of the IAB host through the second DU of the IAB host. The first message includes a first IP address assigned to the first IAB node. The first IAB node determines, based on the first IP address, the first transmission network layer coupling information between the first IAB node and the CU of the IAB host after the first IAB node switches to the second parent node, and the first IAB node updates the context information of the control plane of the first interface based on the first transmission network layer coupling information, and the first lesson can be the F1 interface between the first IAB node and the CU of the IAB host.

[0006] In an embodiment of the present application, when the parent node of the first IAB node is switched due to an IAB topology update, the first IAB node obtains a first IP address, and based on the first IP address, completes the update of the control plane context between the IAB node and the IAB host, thereby avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface. After the switching is completed, the IAB node uses the first IP address to communicate with the CU of the IAB host via the F1 interface, so that the IAB node can use the first IP address to communicate with the CU of the IAB host as soon as possible after the switching is completed, thereby reducing the delay impact on the terminal device service served by the IAB node.

[0007] In one possible design, the first IAB node receives indication information of a CU from the IAB host through the first parent node, or the first message includes indication information. The first IAB node determines the first transport network layer coupling information after switching to the second DU of the IAB host according to the indication information.

[0008] In this way, the IAB node can update the F1 interface TNL coupling as soon as possible after the handover is completed, and restore the ability to provide service to the terminal device as soon as possible, thereby reducing the impact on the service delay of the terminal device.

[0009] In one possible design, the first IAB node generates the first transport network layer coupling information using the first IP address;

[0010] Alternatively, the first IAB node adds the first IP address to the second transmission network layer coupling information to obtain the first transmission network layer coupling information, wherein the second transmission network layer coupling information is the transmission network layer coupling information between the first IAB node and the CU of the IAB host before the first IAB node switches to the second parent node.

[0011] In one possible design, the first message also includes an IP address of the CU of the IAB host, and the IP address of the CU of the IAB host is used for the IAB node to communicate with the CU of the IAB host on the control plane, and / or, the IP address of the CU of the IAB host is used by the IAB node to determine the first transmission network layer coupling information between the first IAB node and the CU of the IAB host.

[0012] In this way, the IAB node can communicate with the CU of the IAB host by using the IP address as soon as possible after the switching is completed, thereby reducing the impact of the IAB node switching on the service delay of the terminal device served by the IAB node.

[0013] In the second aspect, an embodiment of the present application provides a communication method, which is applicable to a scenario in which a first IAB node switches from the DU of a first IAB host to the DU of a second IAB host, that is, the IAB hosts connected before and after the switch are different. The method includes: the first IAB node receives a first message from the CU of the first IAB host. The first message is used to indicate that the first IAB node switches from the first parent node to the second parent node. Among them, the first parent node is the DU of the first IAB host, the second parent node is connected to the CU of the first IAB host through the DU of the first IAB host, the second parent node is the DU of the second IAB host, or the second parent node is connected to the CU of the second IAB host through the DU of the second IAB host. The first message includes the IP address of the first IAB node. After the first IAB node switches to the second parent node, the first IAB node determines the first transmission network layer coupling information between the first IAB node and the CU of the second IAB host after the first IAB node switches to the second parent node based on the first IP address. The first IAB node updates the context information of the control plane of the first interface using the first transport network layer coupling information. The first interface may be an F1 interface between the first IAB node and the second IAB host.

[0014] In an embodiment of the present application, when the IAB topology update causes the parent node of the first IAB node to switch, the first IAB node obtains the first IP address, and based on the first IP address, completes the update of the control plane context between the IAB node and the IAB host, avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface.

[0015] In one possible design, the first IAB node receives indication information of a CU from the first IAB host through the first parent node, or the first message includes indication information. The first IAB node determines the first transport network layer coupling information after the first IAB node switches to the second DU of the IAB host according to the indication information.

[0016] In this way, the IAB node can update the F1 interface TNL coupling as soon as possible after the handover is completed, and restore the ability to provide service to the terminal device as soon as possible, thereby reducing the impact on the service delay of the terminal device.

[0017] In one possible design, the first IAB node generates first transport network layer coupling information between the first IAB node and a CU of a second IAB host by using the first IP address.

[0018] In this way, the IAB node communicates with the CU of the IAB host as soon as possible by using the first IP address after the switching is completed, thereby reducing the impact of the IAB node switching on the service delay of the terminal device served by the IAB node.

[0019] In one possible design, the first message also includes an IP address of the CU of the second IAB host, and the IP address of the CU of the second IAB host is used for the first IAB node to communicate with the CU of the second IAB host on the control plane, and / or, the IP address of the CU of the IAB host is used by the first IAB node to determine the first transmission network layer coupling information between the first IAB node and the CU of the IAB host.

[0020] In this way, the IAB node can communicate with the CU of the IAB host by using the first IP address as soon as possible after the switching is completed, thereby reducing the impact of the IAB node switching on the service delay of the terminal device served by the IAB node.

[0021] In a third aspect, the present application provides a communication method, which is applicable to a scenario in which a first IAB node switches from a first DU of an IAB host to a second DU of an IAB host within the service range of a CU of the same IAB host. The method includes: the CU of the IAB host sends a first message to the first IAB node, the first message is used to instruct the first IAB node to switch from a first parent node to a second parent node, wherein the first parent node is the first DU of the IAB host, or the first parent node is connected to the CU of the IAB host through the first DU of the IAB host, the second parent node is the second DU of the IAB host, or the second parent node is connected to the CU of the IAB host through the second DU of the IAB host, and the first message includes a first IP address of the first IAB node.

[0022] The CU of the IAB host determines, based on the first IP address, the first transmission network layer coupling information between the first IAB node and the CU of the IAB host after the first IAB node switches to the second parent node. The CU of the IAB host updates the context information of the control plane of the first interface based on the first transmission network layer coupling information. The first interface may be an F1 interface between the first IAB node and the second IAB host.

[0023] In one possible design, the CU of the IAB host sends a fourth message to the first IAB node, where the fourth message includes indication information; or the third message includes indication information; wherein the indication information is used to indicate that the first IAB node determines that a timing for the first transmission network layer coupling information occurs after the first IAB node switches to the second parent node.

[0024] In this way, the IAB node can update the F1 interface TNL coupling as soon as possible after the handover is completed, and restore the ability to provide service to the terminal device as soon as possible, thereby reducing the impact on the service delay of the terminal device.

[0025] In a possible design, the CU of the IAB host uses the first IP address to establish the first transmission network layer coupling information between the first IAB node and the CU of the IAB host. Alternatively, the CU of the IAB host adds the first IP address to the second transmission network layer coupling information to obtain the first transmission network layer coupling information, wherein the second transmission network layer coupling information is the transmission network layer coupling information between the first IAB node and the CU of the IAB host before the first IAB node switches to the second parent node.

[0026] In this way, the CU of the IAB host can update the TNL coupling information therein, avoiding the introduction of a large amount of context update signaling due to IAB node switching and the impact on UE service delay.

[0027] In one possible design, the first message also includes an IP address of the CU of the IAB host, the IP address of the CU of the IAB host is used for the first IAB node to communicate with the CU of the IAB host on the control plane, and / or, the IP address of the CU of the IAB host is used by the first IAB node to determine the first transmission network layer coupling information between the first IAB node and the CU of the IAB host.

[0028] In this way, the IAB node can communicate with the CU of the IAB host by using the first IP address as soon as possible after the switching is completed, thereby reducing the impact of the IAB node switching on the service delay of the terminal device served by the IAB node.

[0029] In a possible design, the first IP address is obtained from an IP address pool of a CU of the IAB host, or is obtained from a second DU of the IAB host, or is obtained from an operation and maintenance management entity OAM; or is obtained from a DHCP server.

[0030] In a fourth aspect, an embodiment of the present application provides a communication method, which is applicable to a scenario in which a first IAB node switches from a DU of a first IAB host to a DU of a second IAB host, that is, the IAB hosts connected before and after the switch are different. The method includes: a CU of the first IAB host sends a first message to a CU of a second IAB host, the first message includes an identifier of the first IAB node, the first message is used to request a first IP address, and the CU of the first IAB host receives a second message from the CU of the second IAB host, the second message includes a first IP address assigned to the first IAB node. The CU of the first IAB host sends a third message to the first IAB node, the third message is used to indicate that the first IAB node switches from a first parent node to a second parent node, wherein the first parent node is a DU of the first IAB host, or the first parent node is connected to the CU of the first IAB host through the DU of the first IAB host, the second parent node is a DU of the second IAB host, or the second parent node is connected to the CU of the second IAB host through the DU of the second IAB host, and the third message includes the first IP address of the first IAB node.

[0031] In an embodiment of the present application, when the parent node of the first IAB node is switched due to an IAB topology update, the first IAB node obtains a first IP address, and based on the first IP address, completes the update of the control plane context between the IAB node and the IAB host, thereby avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface. After the switching is completed, the IAB node obtains the first IP address and communicates with the CU of the IAB host via the F1 interface, so that the IAB node can use the first IP address to communicate with the CU of the IAB host as soon as possible after the switching is completed, thereby reducing the impact of service delays on terminal devices served by the IAB node.

[0032] In a possible embodiment, the first message is a switching request message.

[0033] In another possible embodiment, the first message further includes: user plane context information and / or control plane context information of a first interface between the first IAB node and a CU of the first IAB host. The first interface may be an F1 interface between the first IAB node and a second IAB host.

[0034] In a possible embodiment, the CU of the first IAB host sends fourth information to the first IAB node, where the fourth information includes the first IP address of the first IAB node, and the fourth message is used to instruct the first IAB node to switch from the first parent node to the second parent node.

[0035] Among them, the first parent node is the DU of the first IAB host, or the first parent node is the second IAB node connected to the CU of the first IAB host through the DU of the first IAB host, and the second parent node is the DU of the second IAB host, or the second parent node is the third IAB node connected to the CU of the second IAB host through the DU of the second IAB host.

[0036] In a possible embodiment, the CU of the first IAB host sends a message including indication information to the first IAB node; or the third message includes the indication information. The indication information is used to indicate that the first IAB node determines that the timing of the first transport network layer coupling information occurs after the first IAB node switches to the DU of the second IAB host.

[0037] In this way, the IAB node can update the F1 interface TNL coupling as soon as possible after the handover is completed, and restore the ability to provide service to the terminal device as soon as possible, thereby reducing the impact on the service delay of the terminal device.

[0038] In a fifth aspect, an embodiment of the present application provides a communication method, which is applicable to a scenario in which a first IAB node switches from a DU of a first IAB host to a DU of a second IAB host, that is, the IAB hosts connected before and after the switch are different. The method includes: a CU of a second IAB host receives a first message from a CU of a first IAB host, the first message includes an identifier of a first IAB node, and the first message is used to request a first Internet interconnection protocol IP address. The CU of the second IAB host sends a second message to the CU of the first IAB host, and the second message includes a first IP address assigned to the first IAB node. The CU of the second IAB host determines, based on the first IP address, the first transmission network layer coupling information between the first IAB node and the CU of the second IAB host after the first IAB node switches to the second parent node. The CU of the second IAB host updates the context information of the control plane of the first interface based on the first transmission network layer coupling information, and the first interface is the interface between the first IAB node and the CU of the second IAB host.

[0039] In an embodiment of the present application, when the IAB topology update causes the parent node of the first IAB node to switch, the first IAB node obtains the first IP address, and based on the first IP address, completes the update of the control plane context between the IAB node and the IAB host, avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface.

[0040] In a possible embodiment, the CU of the second IAB host generates first transmission network layer coupling information between the first IAB node and the CU of the second IAB host by using the first IP address.

[0041] In this way, the IAB node can update the F1 interface TNL coupling as soon as possible after the handover is completed, and restore the ability to provide service to the terminal device as soon as possible, thereby reducing the impact on the service delay of the terminal device.

[0042] In a possible embodiment, the first message is a switching request message.

[0043] In a possible embodiment, the first message further includes: user plane context information and / or control plane context information of a first interface between the first IAB node and the CU of the first IAB host. The first interface may be an F1 interface between the first IAB node and the second IAB host.

[0044] In a possible embodiment, the CU of the second IAB host determines the control plane context information corresponding to the identifier of the first IAB node; the CU of the second IAB host replaces the second transmission network layer coupling information in the control plane context information with the first transmission network layer coupling information, and the second transmission network layer coupling information is the transmission network layer coupling information between the first IAB node and the CU of the IAB host before the first IAB node switches to the second parent node.

[0045] In this way, for the scenario where the IAB node switches between different IAB host nodes, the F1 interface context of some or all IAB nodes can be obtained in advance, avoiding the large amount of signaling required to re-establish the F1 interface and the corresponding control plane and user plane context after switching, and avoiding the impact on terminal service delays.

[0046] In a possible embodiment, the first IP address is obtained from an IP address pool of the CU of the second IAB host, or is obtained from a DU functional entity of the second IAB host, or is obtained from an operation and maintenance management entity OAM by the CU of the second IAB host, or is obtained from a DHCP server by the CU of the second IAB host.

[0047] In a sixth aspect, the present application provides a communication method, which is applicable to a scenario in which a first IAB node switches from a first DU of an IAB host to a second DU of an IAB host within the service range of a CU of the same IAB host. The method includes: the IAB host CU receives a control plane message from the first IAB node, the control plane message includes a first IP address and a second IP address, the first IP address is the IP address of the first IAB node used when the first IAB node communicates with the IAB host CU through a first parent node; the second IP address is the IP address of the first IAB node used when the first IAB node communicates with the IAB host CU through a second parent node; wherein the first parent node is the first DU of an IAB host of an IAB host, or the first parent node is connected to the CU of an IAB host through the first DU of an IAB host of an IAB host, the second parent node is the second DU of an IAB host of an IAB host, or the second parent node is connected to the CU of an IAB host through the second DU of an IAB host of an IAB host; the IAB host CU replaces the first IP address in the downlink tunnel endpoint information of the user plane of the first interface with the second IP address.

[0048] In an embodiment of the present application, the method facilitates the IAB host CU to perform batch replacement of downlink tunnel information in the F1-U context according to the control plane message, thereby achieving the effect of updating the user plane context of the terminal device and avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface.

[0049] In a seventh aspect, the present application provides a communication method, which is applicable to a scenario in which a first IAB node switches from a first DU of an IAB host to a second DU of an IAB host within the service range of a CU of the same IAB host. The method includes: the first IAB node receives a control plane message from an IAB host CU, the control plane message includes a first IP address and a second IP address, the first IP address is the IP address of the CU of the IAB host used when the first IAB node communicates with the IAB host CU through a first parent node; the second IP address is the IP address of the CU of the IAB host used when the first IAB node communicates with the IAB host CU through a second parent node, wherein the first parent node is the first DU of the IAB host of the IAB host, or the first parent node is connected to the CU of the IAB host through the first DU of the IAB host of the IAB host, and the second parent node is the second DU of the IAB host of the IAB host, or the second parent node is connected to the CU of the IAB host through the second DU of the IAB host of the IAB host. After the first IAB node is switched from the first parent node to the second parent node, the first IAB node replaces the first IP address in the uplink tunnel endpoint information of the user plane of the F1 interface with the second IP address.

[0050] In an embodiment of the present application, the method facilitates the IAB node to perform batch replacement of the downlink tunnel information in the F1-U context according to the signaling, thereby achieving the effect of updating the user plane context of the terminal device and avoiding the service delay and signaling overhead caused by the reconstruction of the F1 interface.

[0051] In an eighth aspect, the present application provides a communication method, which is applicable to a scenario in which a first IAB node switches from a first DU of an IAB host to a second DU of the IAB host within a CU service range of the same IAB host. The method includes: a CU-UP of an IAB host receives a control plane message from a CU-CP of an IAB host, the control plane message including a first IP address and a second IP address, the first IP address being an IP address of the first IAB node used when the first IAB node communicates with the IAB host CU-UP through a first parent node; the second IP address being an IP address of the first IAB node used when the first IAB node communicates with the IAB host CU-UP through a second parent node; wherein the first parent node is a first DU of an IAB host of an IAB host, or the first parent node is connected to the CU-UP of the IAB host through the first DU of an IAB host of an IAB host, and the second parent node is a second DU of an IAB host of an IAB host, or the second parent node is connected to the CU-UP of the IAB host through the second DU of an IAB host of an IAB host; and the CU-UP of the IAB host replaces the first IP address in the downlink tunnel endpoint information of the user plane of an F1 interface with the second IP address.

[0052] In the embodiment of the present application, the IAB donor CU-UP performs batch replacement of the downlink tunnel information in the F1-U context according to the control plane message, thereby achieving the effect of updating the F1-U context of the terminal device and avoiding the need for a large amount of signaling overhead for updating in the prior art.

[0053] In a ninth aspect, the present application provides a communication method, the method comprising: a relay node receives a first message from a CU of a host node through a first DU of the host node, the first message including an IP address of the relay node; the relay node determines, based on the IP address, transmission network layer coupling information between the relay node and the CU when the relay node is connected to the CU through a second DU of the host node; the relay node updates the context information of the control plane of the first interface based on the transmission network layer coupling information; wherein the first interface is an interface between the relay node and the CU, the first DU is a source DU switched by the relay node, and the second DU is a target DU switched by the relay node.

[0054] In an embodiment of the present application, when the parent node of the first IAB node is switched due to an IAB topology update, the first IAB node obtains a first IP address, and based on the first IP address, completes the update of the control plane context between the IAB node and the IAB host, thereby avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface. After the switching is completed, the IAB node uses the first IP address to communicate with the CU of the IAB host via the F1 interface, so that the IAB node can use the first IP address to communicate with the CU of the IAB host as soon as possible after the switching is completed, thereby reducing the delay impact on the terminal device service served by the IAB node.

[0055] In a tenth aspect, the present application provides a communication method, the method comprising: the method comprising: a relay node receives a first message from a target host node through a source host node, the first message comprising an IP address of the relay node; the relay node determines the transmission network layer coupling information between the relay node and the target host node according to the IP address; the relay node updates the context information of the control plane of the first interface according to the transmission network layer coupling information. The first interface is an interface between the relay node and the target host node, the source host node is the source host node to which the relay node switches, and the second host node is the target host node to which the relay node switches.

[0056] In an embodiment of the present application, the source host node includes a host CU and may optionally include a host DU. When the IAB topology update causes the parent node of the first IAB node to switch, the first IAB node obtains a first IP address, and based on the first IP address, completes the update of the control plane context between the IAB node and the IAB host, thereby avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface.

[0057] In an eleventh aspect, the present application provides a communication device, which may be a first IAB node or a chip disposed inside the first IAB node. The communication device has the function of implementing the first aspect, for example, the communication device includes a module or unit or means corresponding to the steps involved in the first aspect, and the function or unit or means may be implemented by software or by hardware, or may be implemented by hardware executing the corresponding software.

[0058] In a possible design, the communication device includes a processing unit and a communication unit, wherein the communication unit can be used to send and receive signals to achieve communication between the communication device and other devices, for example, the communication unit is used to receive first information from a network device; the processing unit can be used to perform some internal operations of the communication device. The functions performed by the processing unit and the communication unit can correspond to the steps involved in the first IAB node in the above aspects.

[0059] In one possible design, the communication device includes a processor and may also include a transceiver, the transceiver is used to send and receive signals, and the processor executes program instructions to complete the method in any possible design or implementation of the first aspect above. Among them, the communication device may also include one or more memories, and the memory is used to couple with the processor. The one or more memories may be integrated with the processor or may be separated from the processor, which is not limited in this application. The memory may store the necessary computer programs or instructions for implementing the functions involved in the first aspect above. The processor may execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, the communication device implements the method in any possible design or implementation involved in the first IAB node of the above aspects.

[0060] In one possible design, the communication device includes a processor and a memory, and the memory may store necessary computer programs or instructions for implementing the functions involved in the first aspect. The processor may execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, the communication device implements the method in any possible design or implementation involved in the first IAB node of the above aspects.

[0061] In one possible design, the communication device includes at least one processor and an interface circuit, wherein the at least one processor is used to communicate with other devices through the interface circuit and execute the method performed by the first IAB node in any possible design or implementation of the first aspect above.

[0062] In a twelfth aspect, the present application provides a communication device, which may be a network device or a chip disposed inside a network device. The communication device is capable of implementing the functions involved in the above-mentioned IAB host aspect, for example, the communication device includes a module or unit or means corresponding to the steps involved in the above-mentioned second aspect, and the functions or units or means may be implemented by software, or by hardware, or by hardware executing the corresponding software implementation.

[0063] In one possible design, the communication device includes a processing unit and a communication unit, wherein the communication unit can be used to send and receive signals to achieve communication between the communication device and other devices, for example, the communication unit is used to send a first message to a first IAB node; the processing unit can be used to perform some internal operations of the communication device. The functions performed by the processing unit and the communication unit can correspond to the steps involved in the above-mentioned IAB host aspect.

[0064] In one possible design, the communication device includes a processor and may also include a transceiver, the transceiver is used to send and receive signals, and the processor executes program instructions to complete the method in any possible design or implementation of the second aspect above. Among them, the communication device may also include one or more memories, and the memory is used to couple with the processor. The one or more memories can be integrated with the processor or can be separated from the processor, which is not limited in this application. The memory can store the necessary computer programs or instructions for implementing the functions involved in the second aspect above. The processor can execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, the communication device implements the method in any possible design or implementation of the above-mentioned IAB host.

[0065] In one possible design, the communication device includes a processor and a memory, and the memory can store necessary computer programs or instructions for implementing the functions involved in the second aspect. The processor can execute the computer program or instructions stored in the memory, and when the computer program or instructions are executed, the communication device implements the method in any possible design or implementation of the above-mentioned IAB host aspect.

[0066] In one possible design, the communication device includes at least one processor and an interface circuit, wherein the at least one processor is used to communicate with other devices through the interface circuit and execute the method in any possible design or implementation of the above IAB host aspect.

[0067] In a thirteenth aspect, the present application provides a computer-readable storage medium, in which computer-readable instructions are stored. When a computer reads and executes the computer-readable instructions, the computer executes a method in any possible design of the above-mentioned aspects.

[0068] In a fourteenth aspect, the present application provides a computer program product. When a computer reads and executes the computer program product, the computer executes the method in any possible design of the above-mentioned various aspects.

[0069] In a fifteenth aspect, the present application provides a chip, comprising a processor, wherein the processor is coupled to a memory and is used to read and execute a software program stored in the memory to implement any possible design method in each of the above aspects.

[0070] These and other aspects of the present application will become more clearly understood in the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1A to Figure 1B A schematic diagram of a network architecture provided for an embodiment of the present application;

[0072] FIG. 2A to FIG. 2B Another schematic diagram of a network architecture provided for an embodiment of the present application;

[0073] Figures 3A to 3B A schematic diagram of a protocol stack structure provided in an embodiment of the present application;

[0074] Figure 4A and Figure 4B A schematic diagram of an applicable scenario provided for an embodiment of the present application;

[0075] Figure 5 A schematic diagram of a first communication method flow chart provided in an embodiment of the present application;

[0076] Figure 6 A detailed flow chart of another communication method provided in an embodiment of the present application;

[0077] Fig. 7A and Figure 7B A schematic diagram of an applicable scenario provided for an embodiment of the present application;

[0078] Figure 8 A detailed flow chart of another communication method provided in an embodiment of the present application;

[0079] Fig. 9 A detailed flow chart of another communication method provided in an embodiment of the present application;

[0080] Fig.10 A detailed flow chart of another communication method provided in an embodiment of the present application;

[0081] Fig.11A and Fig. 11B A detailed flow chart of another communication method provided in an embodiment of the present application;

[0082] Fig. 12A and Fig. 12B A detailed flow chart of another communication method provided in an embodiment of the present application;

[0083] Fig.13 A possible exemplary block diagram of the device involved in the embodiments of the present application;

[0084] Fig.14 A schematic diagram of the structure of a terminal device provided in an embodiment of the present application;

[0085] Fig.15 A schematic diagram of the structure of a network device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0086] The embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0087] The embodiments of the present application can be applied to various mobile communication systems, such as: first radio (new radio, NR) system, long term evolution (long term evolution, LTE) system, advanced long term evolution (advanced long term evolution, LTE-A) system, evolved long term evolution (evolved long term evolution, eLTE) system, future communication systems and other communication systems, specifically, no limitation is made here.

[0088] To facilitate understanding of the embodiments of the present application, first Figure 1A The communication system shown in the figure is used as an example to describe in detail the communication system applicable to the embodiments of the present application. Figure 1A A schematic diagram of a communication system applicable to the communication method of an embodiment of the present application is shown. Figure 1A As shown, the communication system includes an IAB host base station, an IAB node and a terminal device. Figure 1B for Figure 1A Another expression form of the communication system shown has the same essential meaning and will not be repeated here.

[0089] In addition, Figure 1A and Figure 1B The names of interfaces between devices are also shown, such as the wireless interface between the terminal device and the IAB node (named NR Uu interface in the figure) and the wireless interface between the IAB node and the IAB host base station (which can be called NR wireless backhaul interface. Since this interface also communicates based on the NR Uu interface protocol, it is named NR Uu interface in the figure). The names of these interfaces are only examples and do not represent limitations on the interfaces. When the communication system version changes, the corresponding names can also be replaced by the names of corresponding functions in other wireless communication networks.

[0090] Figure 1A The IAB network shown supports multi-hop networking, for example Figure 1A and Figure 1B There may also be one or more intermediate IAB nodes between the IAB node and the IAB host base station.

[0091] Figure 1AThe IAB network shown supports not only multi-hop networking, but also multi-connection networking. There can be at least one transmission path consisting of multiple links between the terminal device served by the IAB node and the IAB host. There can also be one or more transmission paths between the IAB node and the IAB host, and there can be one or more IAB nodes on each transmission path. On a transmission path, each IAB node regards the neighboring node that provides access and backhaul services to it as a parent node, and accordingly, each IAB node can be regarded as a child node of its parent node. For example, in Figure 1A and Figure 1B In the scenario shown, the parent node of the IAB node is the IAB host, and the IAB host regards the IAB node as a child node.

[0092] It should be noted that Figure 1A The IAB networking scenario shown is only exemplary. In the IAB scenario combining multi-hop and multi-connection, other connection forms may exist. For example, the present application can also be applied to the dual connection scenario, which can be as follows: Figure 2A shown. Figure 2A The figure shows the network architecture diagram of E-UTRAN and NR dual connectivity (E-UTRAN NR Dual Connectivity, EN-DC) system. Figure 2A As shown, the communication system includes an evolved packet core (EPC) device, a base station (eNB) of an LTE system, an IAB host, an IAB node, and a terminal device. Figure 2A The EN-DC networking mode shown may also be referred to as non-standalone (NSA) networking of the IAB network. Figure 2B for Figure 2A Another expression form of the communication system shown has the same essential meaning and will not be repeated here.

[0093] Figure 2A In the figure, the base station of the LTE system (eNB) is the main base station (therefore it can also be called Master eNB, abbreviated as MeNB), which provides LTE air interface (LTE Uu) connection for the IAB node, and transmits user plane data and control plane data with the core network EPC through the S1 interface. The IAB host base station is a secondary base station, which provides NR air interface (NR Uu) connection for the IAB node, and transmits user plane data with the core network EPC through the S1 interface. Similarly, the terminal device also supports dual connection. The UE is connected to the main base station (eNB) through the LTE Uu interface and to the secondary base station (IAB node, or IAB host base station) through the NR Uu interface.

[0094] It should be noted that Figure 2A This is just a networking example. The NSA networking of the IAB network also supports multi-hop IAB networking. For example Figure 2A and Figure 2B The terminal devices in the IAB network can be connected to the IAB host base station through two or more IAB nodes, that is, the IAB node can be connected to the IAB host base station through a multi-hop backhaul link. The NSA networking of the IAB network also supports single-hop IAB networking, for example Figure 2A and Figure 2B The terminal device in the network can be connected to the IAB host base station through an IAB node. In addition, when the IAB node is connected to the eNB, it communicates with the eNB through a one-hop LTE link.

[0095] In addition, it should be noted that the dual connection scenario applicable to this application can not only be Figure 2A and Figure 2B The EN-DC networking scenario shown may also be a dual connection consisting of an IAB network and an IAB network, or a connection between an IAB network and other future communication systems. The above examples do not constitute a limitation on the scenario.

[0096] In the embodiment of the present application, the IAB node may also be referred to as a relay node (RN). For the convenience of description, it is referred to as an IAB node below. The IAB node may include at least one mobile terminal (MT) unit and at least one distributed unit (DU). Figure 1A as well as Figure 2A In the description, only an example of an IAB node including an MT unit and a DU is used for description. The MT unit in the IAB node implements the IAB as a terminal to communicate with the parent node of the IAB node and the IAB host node, and has the function of user equipment (UE). The DU in the IAB node provides access services to the terminal devices attached to it or other IAB nodes, and can also communicate with the IAB host node based on the F1 interface. Among them, the MT in the IAB node can also be called the MT functional entity in the IAB node, and the DU in the IAB node can also be called the DU functional entity in the IAB node. For the convenience of description, the MT in the IAB node and the MT functional entity in the IAB node are referred to as "IAB node MT", and the DU in the IAB node and the DU functional entity in the IAB node are referred to as "IAB node DU". The IAB node can provide wireless access services for terminal devices, and the service data or control information of the terminal device is transmitted by the IAB node connecting to the IAB donor or network-side device through a wireless backhaul link.

[0097] The IAB host can be an access network element with complete base station functions, or an access network element with a centralized unit (CU) and a distributed unit (DU) separated. The CU in the IAB host can also be called the CU functional entity in the IAB host, and the DU in the IAB host can also be called the DU functional entity in the IAB host.

[0098] For ease of expression, in the embodiment of the present application, the CU in the IAB host and the CU functional entity in the IAB host are referred to as the CU of the IAB host (also known as IAB-donor-CU), and the DU in the IAB host and the DU functional entity in the IAB host are referred to as the IAB host DU (also known as IAB-donor-DU). The CU of the IAB host may also be in a form in which the control plane (CP) and the user plane (UP) are separated. For example, the CU of an IAB host is composed of a CU-CP (also known as IAB-donor-CU-CP) and multiple CU-UPs (also known as IAB-donor-CU-UPs), which is not limited in the embodiment of the present application.

[0099] The F1 interface involved in the embodiments of the present application is an interface between the DU of the IAB node and the IAB host base station, or an interface between the DU of the IAB node and the CU of the IAB host base station, or an interface between the IAB node and the IAB host base station. The F1 interface may also be referred to as the F1* interface or other names. For the convenience of description, in the embodiments of the present application, they may be uniformly referred to as F1 interfaces, but the name is not limited.

[0100] It should be noted that the F1 interface may also be an interface between functional entities within a device. For example, for a base station including a DU and a CU, the F1 interface may be an interface between the DU within the base station and the CU within the base station.

[0101] The F1 interface involved in the embodiment of the present application supports the user plane protocol and the control plane protocol. For example, Figure 3A , which is a schematic diagram of a protocol stack of a user plane protocol provided in an embodiment of the present application. Figure 3AIn the description, the link between the terminal device and the IAB host includes the terminal device, IAB node 2, IAB node 1, and IAB host. The IAB host consists of the IAB host DU (IAB-donor-DU) and the IAB host CU (IAB-donor-CU). The IAB host CU includes the control plane function unit (IAB-donor-CU-CP) and the user plane function unit (IAB-donor-CU-UP) of the IAB host CU. Figure 3A This is an example of the user plane protocol stack, so IAB only shows the IAB-donor-CU-UP part. Correspondingly, Figure 3B Only the IAB-donor-CU-CP part is shown in the control plane protocol stack.

[0102] Figure 3A In the protocol layer between the terminal device and the IAB host, the peer protocol layers include the Service Data Adaptation Protocol (SDAP) layer and the Packet Data Convergence Protocol (PDCP) layer. The peer protocols between the terminal device and the IAB node 2 include the Radio Link Control (RLC) layer, the Medium Access Control (MAC) layer and the Physical (PHY) layer.

[0103] In the user plane of the F1 interface between the IAB node 2 and the IAB host, the peer protocols include the General Packet Radio Service (GPRS) Tunnelling Protocol User Plane (GTP-U) layer, the User Datagram Protocol (UDP) layer, and the Internet Protocol (IP) layer. Optionally, the user plane protocol layer of the F1 interface also includes a PDCP layer and / or an IP Security (IPsec) layer. In a possible implementation, the IPsec layer or the PDCP layer is located above the IP layer and below the GTP-U layer.

[0104] The equivalent protocol layers between IAB node 2 and IAB node 1 include the Backhaul Adaptation Protocol (BAP) layer, RLC layer, MAC layer and PHY layer. Correspondingly, the equivalent protocol between IAB node 1 and IAB host includes the BAP layer, RLC layer, MAC layer and PHY layer.

[0105] Combination Figure 3A , for example, Figure 3B , which is a schematic diagram of a protocol stack of a control plane protocol provided in an embodiment of the present application.

[0106] Figure 3B In the present invention, the peer-to-peer protocols between the terminal device and the IAB host include the radio resource control (RRC) layer and the PDCP layer. The peer-to-peer protocols between the terminal device and the IAB node 2 include the RLC layer, the MAC layer and the PHY layer.

[0107] In the control plane of the F1 interface between the IAB node 2 and the IAB host, the peer protocols include the F1 application protocol (F1AP) layer, the stream control transport protocol (SCTP) layer, and the IP layer. Optionally, the control plane protocol layer of the F1 interface also includes one or more of the PDCP layer, the IPsec layer, and the datagram transport layer security (DTLS) layer. In a possible implementation, the IPsec layer, the PDCP layer, or the DTLS layer is located above the IP layer and below the F1AP layer.

[0108] The peer-to-peer protocol between the IAB node 2 and the IAB node 1 includes the BAP layer, the RLC layer, the MAC layer and the PHY layer. Correspondingly, the peer-to-peer protocol between the IAB node 1 and the IAB host includes the BAP layer, the RLC layer, the MAC layer and the PHY layer.

[0109] The BAP layer has at least one of the following capabilities: adding routing information (Routing information) that can be recognized by the wireless backhaul node to the data packet, performing routing selection based on the routing information that can be recognized by the wireless backhaul node, adding identification information related to the quality of service (QoS) requirements that can be recognized by the wireless backhaul node to the data packet, performing QoS mapping on multiple links containing wireless backhaul nodes for the data packet, adding data packet type indication information to the data packet, sending flow control feedback information to the node with flow control capability, and sending backhaul link failure indication information to the child node. It should be noted that the name of the protocol layer with these capabilities is not necessarily the BAP layer. Those skilled in the art can understand that as long as the protocol layer has these capabilities, it can be understood as the BAP layer in the embodiment of the present application. Among them, the routing information that can be recognized by the IAB node can be one or more of the information such as the identification of the terminal, the identification of the IAB node to which the terminal device is connected, the identification of the host node, the identification of the Donor-DU, the identification of the Donor-CU, and the identification of the transmission path.

[0110] Exemplarily, a node with flow control capability may be a host node, Donor-DU, Donor-CU, a parent node of an IAB node, or the like, which is a node that provides backhaul services for an IAB node. The content of the flow control feedback information may include one or more of the following information: the cache status and load level of the IAB node, the status of a certain link of the IAB node (such as link blockage or link resume or link quality information, etc.), the bandwidth and transmission delay of a certain link of the IAB node, the sequence number of the data packet lost by the IAB node, the sequence number of the data packet that the IAB node has successfully sent to the terminal or its child node, etc.

[0111] In addition, in a possible scenario, the functionality of the BAP layer may be extended on the functionality of any layer (eg, RLC layer, MAC layer, PDCP layer, etc.) or any multiple layers included in layer 2 without the need for an additional protocol layer.

[0112] It should be noted that the functions and effects of the protocol layer described above can be referred to the description in the existing standards and will not be repeated here.

[0113] It should be noted that the IAB node MT may have a UE protocol stack, and the communication protocol stack between the IAB host and the parent node can refer to Figure 3A and Figure 3B In this case, the IAB node may also have an RRC layer, and an RRC connection may be established with the IAB host to communicate based on the RRC layer.

[0114] It is understandable that the embodiments of the present application FIG. 3A to FIG. 3B The protocol stack architecture in the IAB network shown in is only an example. The method provided in the embodiment of the present application does not rely on the example, but the example makes the method provided in the embodiment of the present application easier to understand.

[0115] In the embodiment of the present application, the terminal device is a device with a wireless transceiver function or a chip that can be set in the device. Among them, the device with a wireless transceiver function can also be called a user equipment (UE), an access terminal, a user unit, a user station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a user agent or a user device. In practical applications, the terminal device in the embodiment of the present application can be a mobile phone, a tablet computer, a computer with a wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. The embodiment of the present application does not limit the application scenario. In the present application, the aforementioned device with a wireless transceiver function and the chip that can be set in the device are collectively referred to as a terminal device.

[0116] In an embodiment of the present application, the network side device may be a wireless access device under various standards, such as an evolved Node B (eNB), a radio network controller (RNC) or a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (for example, a home evolved NodeB, or a home Node B, HNB), a baseband unit (BBU), a wireless local area network (WLAN), an access point (AP) in the system, a wireless relay node, a wireless backhaul node, a transmission point (TRP or TP), etc. It may also be a gNB or a transmission point (TRP or TP) in a 5G (NR) system, one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or it may also be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), or a DU in a centralized-distributed (CU-DU) architecture, etc.

[0117] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. A person of ordinary skill in the art can appreciate that with the evolution of the network architecture and the emergence of other business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0118] Some scenarios in the embodiments of the present application are illustrated by taking the IAB scenario in a wireless communication network as an example. It should be pointed out that the solutions in the embodiments of the present application can also be applied to other wireless communication networks, and the corresponding names can also be replaced by the names of corresponding functions in other wireless communication networks.

[0119] The communication method provided in the embodiment of the present application involves two scenarios: F1 interface control plane context update and F1 interface user plane context update. The F1 interface control plane context update will be described in the following scenarios 1 and 2. The F1 interface user plane context update will be described in scenarios 3, 4 and 5. Embodiment 1

[0120] Scenario 1, in an embodiment of the present application, the IAB host includes a CU of the IAB host, a first DU of the IAB host, and a second DU of the IAB host, and the first IAB node switches from the first DU of the IAB host to the second DU of the IAB host within the service range of the CU of the same IAB host, that is, the DUs of the IAB host connected before and after the switching are different. Among them, the first IAB node can be an IAB node directly connected to the IAB host, and can also be connected to the IAB host through at least one hop wireless backhaul link.

[0121] For example, Figure 4A As shown, the IAB node 1 is directly connected to the DU1 of the IAB host before the switching, and the IAB node 1 is directly connected to the DU2 of the IAB host after the switching. The first IAB node in the scenario 1 may refer to Figure 4A IAB node 1 in the.

[0122] For example, Figure 4B As shown, before the handover, IAB node 3 is connected to DU1 of the IAB host through a one-hop wireless backhaul link (or through IAB node 1), and after the handover, IAB node 3 is connected to DU2 of the IAB host through a one-hop wireless backhaul link (or through IAB node 2). The first IAB node in this scenario may refer to Figure 4B IAB node 3 in.

[0123] It should be noted that the IAB node 1 whose parent node has been replaced may have other child nodes (for example, the child node connected to the IAB node 1 is the IAB node 2), or the IAB node 1 whose parent node has been replaced may have other secondary child nodes (for example, the secondary child node IAB node 3 connected to the IAB node 2, or the grandchild node IAB node 4 of the child node IAB node 2, etc.).

[0124] Combined with the previous description, such as Figure 5 FIG. 1 is a flow chart of the first communication method provided in the embodiment of the present application. Figure 5 , the method comprises the following steps.

[0125] Step 501: A CU of an IAB host sends a first message to a first IAB node.

[0126] In one possible case, the CU of the IAB host may also be replaced by the CU-CP of the IAB host.

[0127] The first message is used to instruct the first IAB node to switch from the first parent node to the second parent node, wherein the first parent node may be the first DU of the IAB host, or the first parent node may be the second IAB node connected to the CU of the IAB host through the first DU of the IAB host, the second parent node may be the second DU of the IAB host, or the second parent node may be the third IAB node connected to the CU of the IAB host through the second DU of the IAB host.

[0128] For example, the first IAB node is IAB node 1, and the first parent node is Figure 4A The IAB host DU1 connected to the IAB node 1 in the example, the second parent node can be Figure 4A The IAB host DU2 to which the IAB node 1 is connected.

[0129] In another example, the first IAB node is Figure 4B IAB node 3, the first parent node is Figure 4B The second parent node is IAB node 1 connected to IAB node 3. Figure 4B The IAB node 2 is connected to the IAB node 3.

[0130] In a possible implementation, the first message may be a high-level radio resource control (RRC) reconfiguration message. Optionally, when the first parent node is different from the second parent node, the RRC reconfiguration message may include a handover command, or the handover command is the first message, or the first message may be carried in other RRC messages.

[0131] In other possible implementations, when the first parent node is the same as the second parent node, the first message may include updated routing configuration information. Figure 4A The IAB node 2 in the CU can receive the first message from the IAB host, which can include updated routing configuration information. The IAB node 2 (specifically, its MT part) does not need to perform switching in the cells served by two different parent nodes. It only needs to update the routing configuration of its BAP layer according to the received first message, and update the transmission route of the first DU originally transmitted from the first parent node to the IAB host to the transmission route of the second DU transmitted from the first parent node to the IAB host, thereby realizing switching from the first DU connected to the IAB host to the second DU connected to the IAB host.

[0132] In a possible implementation, the first message may include a first Internet Protocol (IP) address assigned to the first IAB node. The first IP address may include one IP address or multiple IP addresses. The first IP address is used for the first IAB node to communicate with the second DU of the IAB host after switching to the second DU of the IAB host. The CU of the IAB host obtains the first IP address in the following manner: it may be obtained from an IP address pool maintained by the CU of the IAB host, or it may be obtained from the second DU of the IAB host, or it may be obtained from the operation administration and maintenance (OAM), or it may be requested from a dynamic host configuration protocol (DHCP) server. On the one hand, the first IAB node may complete the update of the control plane context between the IAB node and the CU of the IAB host based on the first IP address. On the other hand, carrying the first IP address in the first message may enable the IAB node to communicate with the CU of the IAB host as soon as possible using the first IP address after the switching is completed, thereby reducing the service delay of the terminal device served by the IAB node.

[0133] In a possible implementation, the first message may also include an IP address of the IAB host CU, which is used for the IAB node to communicate with the CU of the IAB host on the control plane, and / or the IP address of the CU of the IAB host is used by the IAB node to determine the first transport network layer (TNL) coupling information between the first IAB node and the CU of the IAB host. In this way, the IAB node can use the IP address to communicate with the CU of the IAB host as soon as possible after the switching is completed, reducing the impact of the IAB node switching on the terminal device service delay of the IAB node service.

[0134] Step 502: The first IAB node receives a first message.

[0135] In a possible embodiment, the first message is an RRC reconfiguration message, and the first IAB node receives an RRC reconfiguration message from the CU of the IAB host. The reconfiguration message includes a switching command, and the switching command may be an information element that specifically requires the first IAB node to perform reconfiguration with sync, and is used to instruct the first IAB node to switch to a cell served by a second parent node, wherein the second parent node may be a cell served by a second DU of the IAB host.

[0136] In another possible embodiment, when the first parent node is the same as the second parent node, the first IAB node receives a first message from the CU of the IAB host, which may include updated routing configuration information, indicating the uplink transmission routing configuration of the first IAB node to the second DU of the IAB host. The updated routing configuration information may specifically include any one or more of the following: one or more BAP layer routing identifiers pointing to the second DU of the IAB host, and a next hop node identifier corresponding to any BAP layer routing identifier (i.e., the BAP layer identifier of the parent node of the first IAB node). Among them, the BAP layer routing identifier pointing to the second DU of the IAB host includes the BAP layer identifier (i.e., the BAP address) of the IAB host (specifically, the CU of the IAB host, or the second DU of the IAB host), and may also include a path identifier from the first IAB node to the second DU of the IAB host. The first message may specifically be an F1AP message, such as a gNB-CU configuration update (base station CU configuration update) message, and the first message may also be an RRC message, such as an RRC reconfiguration message.

[0137] Step 503: The first IAB node performs parent node switching according to the first message, switching from the first parent node to accessing the second parent node.

[0138] The first parent node is the first DU of the IAB host, and the second parent node is the second DU of the IAB host, that is, the first IAB node switches from being connected to the first DU of the IAB host to being connected to the second DU of the IAB host.

[0139] Specifically, the first IAB node (specifically, it can be the MT part of the first IAB node) can perform switching and send a random access request in the cell served by the second parent node. When the first IAB node receives the response message of the second parent node, it can continue to perform subsequent access steps to complete access to the cell served by the second parent node.

[0140] In other possible embodiments, when the first parent node is the same as the second parent node, the first IAB node (specifically, its MT part) does not need to perform switching between cells served by two different parent nodes, but only needs to update the routing configuration of its BAP layer according to the received first message, and update the transmission route of the first DU originally transmitted from the first parent node to the IAB host to the transmission route of the second DU transmitted from the first parent node to the IAB host, thereby achieving switching from the first DU connected to the IAB host to the second DU connected to the IAB host.

[0141] Step 504: The first IAB node obtains a first IP address, and determines first TNL coupling information between the first IAB node and the CU of the IAB host according to the first IP address.

[0142] In a possible manner, the first message received by the first IAB node includes the first IP address, and after the first IAB node receives the first message in step 501, it obtains the first IP address.

[0143] In another possible manner, the first IAB node may obtain the first IP address from the OAM. In another possible manner, the first IAB node may obtain the first IP address from the second DU of the IAB SU. In both cases, the first message may not include the first IP address.

[0144] It should be noted that, in the embodiment of the present application, the TNL coupling information is information describing the TNL coupling, and may specifically include endpoint information of the TNL coupling (also referred to as stream control transport protocol (SCTP) coupling). The endpoint information of the TNL coupling may specifically be the local endpoint information and / or the opposite endpoint information of the TNL coupling, and each TNL coupling endpoint information may specifically be a set of IP addresses corresponding to the endpoint. The IP address set includes at least one IP address, and the first IAB node may update the TNL coupling information by updating the IP address in the IP address set. In the embodiment of the present application, the first TNL coupling information refers to information describing the first TNL coupling, which is the TNL coupling information when the first IAB node is connected through the first DU; the second TNL coupling information refers to information describing the second TNL coupling, which is the TNL coupling information when the first IAB node is connected through the second DU. The IP address set in the first TNL coupling information is different from the IP address set in the second TNL coupling information. The first TNL coupling and the second TNL coupling are both TNL couplings between the first IAB node and the CU of the IAB host, and the two may be two different TNL couplings, or the first TNL coupling is a TNL coupling obtained by updating the endpoint information of the second TNL coupling.

[0145] Specifically, in a possible embodiment, the first IAB node can use the first IP address to establish a first TNL coupling between the first IAB node and the CU of the IAB host, and generate first TNL coupling information. For the first IAB node, the local endpoint of the first TNL coupling is the first IAB node, and the opposite endpoint is the CU of the IAB host. The first TNL coupling information includes a set of IP addresses corresponding to the local endpoint and / or the opposite endpoint of the first TNL coupling, wherein the set of IP addresses corresponding to the local endpoint includes the first IP address.

[0146] In another possible embodiment, if before the switching, a second TNL coupling has been established between the first IAB node and the CU of the IAB host, and the first IAB node maintains the second TNL coupling information, the first IAB node updates the second TNL coupling information using the first IP address, that is, the first IP address is added to the IP address set corresponding to the TNL coupling local endpoint in the second TNL coupling information to generate the first TNL coupling information.

[0147] Optionally, before executing step 503, the first IAB node may also receive indication information from the CU of the IAB host, or the first message may include indication information, which is used to indicate that the first IAB node determines that the timing of the first TNL coupling information occurs after the first IAB node switches to the second parent node. For example, the first IAB node sends an RRC reconfiguration completion message to the CU of the IAB host, indicating that the first IAB node switches to the second parent node. The second parent node may be the second DU of the IAB host; or a third IAB node connected to the CU of the IAB host through the second DU of the IAB host. In this way, the IAB node performs the update of the F1 interface TNL coupling as soon as possible after the switch is completed, restores the ability to provide terminal device service services as soon as possible, and reduces the impact on terminal device service delays.

[0148] Step 505: The CU of the IAB host determines first TNL coupling information between the first IAB node and the CU of the IAB host according to the first IP address.

[0149] In a possible embodiment, the CU of the IAB host can use the first IP address to establish a first TNL coupling between the first IAB node and the CU of the IAB host, and generate first TNL coupling information. For the CU of the IAB host, the local endpoint of the first TNL coupling is the CU of the IAB host, and the opposite endpoint is the first IAB node. The first TNL coupling information includes an IP address set corresponding to the first TNL coupling endpoint, and the IP address set includes the first IP address.

[0150] In another possible embodiment, if before the switching, a second TNL coupling has been established between the CU of the IAB host and the first IAB node, and the second TNL coupling information is maintained in the CU of the IAB host, the CU of the IAB host updates the second TNL coupling information using the first IP address, that is, the first IP address is added to the IP address set corresponding to the TNL coupling opposite-side endpoint in the second TNL coupling information to generate the first TNL coupling information. Exemplarily, the first IAB node may send an address configuration change (ASCONF) data block (Chunk) to the CU of the IAB host, which carries the first IP address to be added, and optionally, may also carry indication information for identifying the first TNL coupling (for example, the indication information is the IP address set of the first IAB node corresponding to the first TNL coupling). After receiving the ASCONF, the CU of the IAB host adds the first IP address to the IP address set corresponding to the first TNL coupling TNL coupling opposite-side endpoint maintained by it, and then may return an address configuration confirmation (ASCONF-ACK) data block (Chunk) to the first IAB node, and return the processing status of the ASCONF parameters to the first IAB node (for example, configuration success or error). Afterwards, the CU of the IAB host may use the first IP address to send a data block related to the first TNL coupling to the first IAB node.

[0151] In step 503 and step 504, the establishment of the first TNL coupling between the first IAB node and the CU of the IAB host may adopt a four-step handshake process, which is briefly described as follows:

[0152] In the first step, the first IAB node sends an initiation (INIT) data block to the CU of the IAB host to initiate the establishment of an SCTP connection. The initiation data block contains the necessary parameters such as the initiation tag assigned by the first IAB node to the connection, the receiving window capacity reserved for the connection, the number of recommended output streams, the number of input streams, and the initial transmission sequence number (TSN) for sending data on the connection, as well as optional parameters such as IP address parameters, COOKIE expiration prevention parameters, host name address parameters, and supported address type parameters. After sending INIT, the first IAB node starts an INIT timer and enters the COOKIE wait (WAIT) state.

[0153] In the second step, after receiving the INIT data block sent by the first IAB node, the CU of the IAB host sends an initialization acknowledgement (INIT ACK) data block to the first IAB node, which contains the state record information (Cookie). The STATE COOKIE parameters include the message authentication code (MAC), the timestamp generated by the COOKIE, the life span of the COOKIE, and the necessary information for establishing the coupling. Among them, the MAC is calculated by the necessary information and the secret key of the CU end of the IAB host.

[0154] In the third step, after receiving the INIT-ACK data block, the first IAB node first stops the INIT timer to leave the COOKIE-WAIT state, and then sends a record information repeat COOKIE ECHO data block to the CU of the IAB host, and brings back the STATE COOKIE parameters in the received INITACK data block.

[0155] In the fourth step, the CU of the IAB host sends a COOKIE-ACK data block to the first IAB node, notifying the first IAB node that the TNL association (specifically, it may be, for example, the first TNL association) is successfully established.

[0156] Optionally, the embodiment of the present application also includes the following step 505.

[0157] Step 506: The first IAB node updates the context information of the control plane of the F1 interface using the first TNL coupling information. The F1 interface is an interface between the first IAB node and the CU of the IAB host.

[0158] In a possible embodiment, the first IAB node and the CU of the IAB host use the second TNL coupling between the two nodes to transmit the control plane message of the F1 interface, so the context information of the control plane of the F1 interface maintained by the first IAB node includes the second TNL coupling information. The first IAB node can generate the first TNL coupling information after updating the second TNL coupling using the first IP address, and replace the second TNL coupling information in the context information of the control plane of the F1 interface with the first TNL coupling information. When the first IAB node generates the first TNL coupling information after updating the second TNL coupling using the first IP address, the first IP address can be added to the IP address set of the local endpoint in the second TNL coupling information, and other IP addresses already in the IP address set can also be deleted.

[0159] In another possible embodiment, the first IAB node and the CU of the IAB host utilize the second TNL coupling between the two nodes to transmit the control plane message of the F1 interface. Therefore, the context information of the F1 interface control plane maintained by the first IAB node includes the second TNL coupling information. After the first IAB node establishes a new first TNL coupling between the CU of the IAB host using the first IP address, the first IAB node can add the first TNL coupling information to the context information of the F1 interface control plane maintained by it, that is, use the first TNL coupling as one of the TNL couplings for carrying the F1 interface control plane message between the first IAB node and the CU of the IAB host.

[0160] Step 507: The CU of the IAB host updates the context information of the control plane of the F1 interface with the first TNL coupling information.

[0161] In a possible embodiment, the first IAB node and the CU of the IAB host use the second TNL coupling between the two nodes to transmit the control plane message of the F1 interface, so the context information of the control plane of the F1 interface maintained by the CU of the IAB host includes the second TNL coupling information, and the CU of the IAB host can generate the first TNL coupling information after updating the second TNL coupling using the first IP address, and replace the second TNL coupling information in the context information of the control plane of the F1 interface with the first TNL coupling information. When the CU of the IAB host generates the first TNL coupling information after updating the second TNL coupling using the first IP address, the first IP address can be added to the IP address set of the opposite endpoint in the second TNL coupling information, and other IP addresses already in the IP address set can also be deleted.

[0162] In another possible embodiment, the first IAB node and the CU of the IAB host use the second TNL coupling between the two nodes to transmit the control plane message of the F1 interface. Therefore, the context information of the F1 interface control plane maintained by the CU of the IAB host includes the second TNL coupling information. After the CU of the IAB host uses the first IP address to newly establish the first TNL coupling with the first IAB node, the first TNL coupling information can be added to the context information of the F1 interface control plane maintained by it, that is, the first TNL coupling is used as one of the TNL couplings for carrying the F1 interface control plane message between the first IAB node and the CU of the IAB host.

[0163] In an embodiment of the present application, the TNL coupling information in the context information of the control plane of the F1 interface is information related to the TNL coupling used to carry the control plane message of the F1 interface (including, for example, the source IP address and / or target IP address used by the TNL coupling), for example, the first TNL coupling information includes the first IP address of the first IAB node.

[0164] It should be noted that, in other possible embodiments, the above Figure 5 The steps 501 to 506 shown may all be executed, or some of the steps may be executed. In addition, there is not necessarily a strict order of execution between the above steps 501 to 506. For example, step 506 may be executed first, and then step 505, or step 505 and step 506 may be executed in parallel. The embodiments of the present application do not make any specific limitations on this.

[0165] Figure 6 In the embodiment of the present application, the first IAB node is further configured as the first DU (ie, Figure 6 The IAB host DU1 in the Figure 4A Taking the IAB node 1 in FIG. 1 as an example, the above communication method is illustrated.

[0166] In step 600, the DU functional entity of the IAB node 1 uses one or more IP addresses to establish a second TNL coupling information with the CU of the IAB host, and the F1 application layer protocol (F1 application protocol, F1AP) message between the IAB node 1 and the CU of the IAB host is carried on the second TNL coupling information. In this step 601, the one or more IP addresses are IP addresses related to the DU 1 of the IAB host obtained after the IAB node 1 is connected to the DU 1 of the IAB host.

[0167] Step 601: IAB node 1 sends a measurement report to the IAB host CU.

[0168] Step 602: The CU of the IAB host makes a switching decision according to the measurement report, that is, switches the IAB node 1 to the DU 2 of the IAB host.

[0169] Optionally, in step 602, the CU of the IAB host may obtain a new IP address (ie, a new IP address) for the IAB node 1 to be used on the path after the switch. Figure 5 Specifically, the CU of the IAB host can obtain one or more new IP addresses. The number of IP addresses to be obtained can refer to the number of IP addresses configured by IAB node 1. The CU of the IAB host obtains the IP address in the following ways: it can obtain it from the IP address pool maintained by itself, or it can obtain the IP address from DU 2 of the IAB host, or it can request the IP address from the DHCP server, or it can also obtain it from OAM.

[0170] Optionally, the method may further include step 603 , where the CU of the IAB host sends indication information to the IAB node 1 .

[0171] The indication information may be carried in an update message (specifically, an F1AP message, such as a gNB-CUCONFIGURATION UPDATE message), wherein the update message includes at least one of the following: (1) TNL coupling information to be removed, (2) TNL coupling information to be added, and (3) TNL coupling information to be updated. Each of these three coupling information may include one or more items. The first IAB node may determine the first transport network layer coupling information based on the indication information after the first IAB node switches to the second DU of the IAB host.

[0172] Wherein, the transport network layer address information (the transport network layer address information of the IAB host CU, and optionally, the transport network layer address information of the DU part of the IAB node 1) contained in each item of the TNL association information to be removed is the transport network layer address information used by the TNL association currently established between the IAB node 1 and the CU of the IAB host. It should be noted that if the TNL association information to be removed is included, the IAB node 1 needs to perform the corresponding removal operation before step 605.

[0173] Among them, (2) the TNL association information to be added is the TNL association information established by the IAB node 1 through the new path after the switching is completed, and the transmission network layer address information contained in each item of the association information (including the transmission network layer address information of the IAB donor CU, and may also include the transmission network layer address information allocated by the IAB donor CU to the DU part of the IAB node 1) is the transmission network layer address information to be used on the new path. In this application, the transmission network layer address information of a node can be the IP address of the node, or the IP address of the node and the transmission layer port number.

[0174] Among them, (3) the TNL association information needs to be updated, including one or more TNL association lists that need to be updated, each of which contains the transport network layer address information of the IAB host CU and the purpose indication of the TNL association, which will be used to overwrite (or replace) the corresponding information corresponding to the existing TNL association between the IAB node 1 and the CU of the IAB host.

[0175] It should be noted that step 603 may also be performed after step 604 .

[0176] Step 604: The CU of the IAB host sends a first message to the IAB node 1, where the first message is, for example, an RRC reconfiguration message, which includes a handover command. The handover command may specifically be, for example, a reconfiguration with Sync information element (IE) in the RRC message, or a mobility control information (Mobility Control Information) information element, where the handover command includes instructions for the IAB node 1 to handover to the cell connected to the service of the IAB host DU2.

[0177] Step 605, IAB node 1 performs switching, initiates an access request to the new parent node, ie, IAB node host DU2, and completes access on the new path.

[0178] Optionally, the method further includes step 606, where the IAB node 1 obtains a first IP address.

[0179] In a possible embodiment, the above step 606 may be performed together with step 604, and the IAB node 1 may obtain the first IP address from the CU of the IAB host (for example, the first message carries the first IP address of the IAB node 1). In other possible embodiments, the IAB node 1 may obtain the first IP address from OAM or by executing the Dynamic Host Protocol (DHCP).

[0180] Optionally, before executing this step, the IAB node 1 may also obtain the IP address of the CU of the IAB host from the CU of the IAB host.

[0181] Step 607 , the CU of the IAB host sends a message to perform routing configuration on the intermediate nodes that the IAB node passes through on the new path, and these intermediate nodes include the IAB host DU2 .

[0182] In a possible embodiment, if the IAB node 1 is connected to the IAB host through a multi-hop backhaul network, then in this step, it is also necessary to perform routing configuration on the intermediate IAB nodes on the transmission path between the IAB node 1 and the IAB donor DU2. The content of the routing configuration for the intermediate node includes one or more downlink routing items related to the IAB node 1, and may also include one or more uplink routing items related to the IAB node 1. The downlink routing item related to the IAB node 1 includes the routing information of the IAB node 1 and the corresponding next hop node. The routing information of the IAB node 1 may be an adaptation layer routing identifier (BAP routing ID), which is composed of the BAP layer identifier (BAP address) and the path identifier (BAP pathID) of the IAB node 1, wherein the path identifier is optional and is used to indicate the transmission path between the IAB host and the IAB node 1. The uplink routing item related to the IAB node 1 includes the routing information of the IAB host and the corresponding next hop node. The routing information of the IAB host may be an adaptation layer routing identifier, which is composed of the BAP layer identifier and path identifier of the IAB host, wherein the path identifier is optional content and is used to indicate the transmission path between the IAB node 1 and the IAB host. The IAB host in this step, when the IAB host is a CU-DU separation structure, can be specifically understood as the IAB host DU, or the CU of the IAB host. For the parent node of the IAB node 1 on the new path, the content of the routing configuration may also include the adaptation layer identifier (BAPaddress) of the IAB node 1.

[0183] Step 608: The CU of the IAB host sends a message to configure routing for the IAB node 1. The content includes one or more uplink routing items related to the IAB node 1. The specific description of the uplink routing items can be understood by referring to the description in step 607.

[0184] In step 609, the IAB node 1 uses the first IP address to establish a new first TNL association with the CU of the IAB host (specifically, it can be the CUCP of the IAB host), and generates first TNL association information. The first TNL association is established according to the IP address and / or transport layer port number information in the newly created or updated list provided by the CU in step 603. Alternatively, the IAB node 1 and / or the CU of the IAB host uses the multi-homing feature supported by the SCTP protocol to add the first IP address to the endpoint information corresponding to the existing second TNL association as the first IP address available for transmitting the data block related to the second TNL association.

[0185] Step 610: The IAB node 1 and the CU of the IAB host respectively update the TNL coupling information for carrying F1-C.

[0186] This step can be accomplished in two ways.

[0187] Mode 1: IAB node 1 sends a GNB CU CONFIGURATION UPDATE ACKNOWLEDGE (CU configuration update success) message to the CU of the IAB host, which carries the transport network layer address of the CU of the IAB host corresponding to the newly established first TNL coupling.

[0188] Method 2: IAB node 1 sends a GNB-DU CONFIGURATION UPDATE message to the CU of the IAB host, which carries the gNB DU ID of IAB node 1 and the second TNL association information to be deleted. When transmitting the message, the newly established first TNL association is used. In this way, after receiving the message, the CU of the IAB host can delete the corresponding second TNL association information between the IAB node DU and transmit the F1AP message between the two in the subsequent transmission through the newly established first TNL association.

[0189] It should be noted that method 1 is applicable when step 603 is executed. If method 2 is adopted, the CU of the IAB host will also return a response message to the IAB node. The response message may be GNB-DU CONFIGURATION UPDATE ACKNOWLEDGE (DU configuration update success message) or GNB-DU CONFIGURATION UPDATE FAILURE (DU configuration update failure). The step of the CU of the IAB host sending the response message to the IAB node 1 is as follows: Figure 6 Not shown.

[0190] Through these two methods, in a mobile scenario where the IAB node does not change the IAB host, the TNL coupling information of the F1-C signaling between the CU carrying the IAB host and the IAB node can be updated without re-establishing the F1 connection.

[0191] It should be noted that the above step 610 is an optional step. If in step 609, the IAB node 1 uses the multi-homing feature supported by the SCTP protocol to add the first IP address to the information corresponding to the existing first TNL coupling as the first IP address that can be used to transmit the first TNL coupling related data block, step 610 may not be executed.

[0192] In addition, it should be noted that during the topology update process, if the IAB node whose parent node is replaced has child nodes (other IAB nodes connected to the IAB node 1) or secondary child nodes (child nodes of child nodes, or grandchild nodes of child nodes, etc.), the control plane context of these child nodes or secondary child nodes also needs to be updated. Figure 4A IAB node 2 in the Figure 4B When the IAB node 3 in the IAB host is used, the TNL coupling between the first IAB node and the CU of the IAB host can be updated by executing steps 603, 606 to 610.

[0193] In an embodiment of the present application, when the parent node of the first IAB node is switched due to an IAB topology update, the first IAB node obtains a first IP address, and based on the first IP address, completes the update of the control plane context between the IAB node and the IAB host, thereby avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface. After the switching is completed, the IAB node obtains the first IP address and communicates with the CU of the IAB host via the F1 interface, so that the IAB node can use the first IP address to communicate with the CU of the IAB host as soon as possible after the switching is completed, thereby reducing the impact of service delays on terminal devices served by the IAB node. Embodiment 2

[0194] Scenario 2, in an embodiment of the present application, in a state where the IAB host is DU and CU are not separated, the first IAB node switches from the first IAB host to the second IAB host, that is, the IAB hosts connected before and after the switch are different; or in a state where the IAB host is DU and CU are separated, that is, the first IAB host includes CU and DU, and the second IAB host includes CU and DU. The first IAB node switches from the DU of the first IAB host to the DU of the second IAB host, that is, the IAB hosts connected before and after the switch are different. Among them, the first IAB node can be an IAB node directly connected to the first IAB host or the second IAB host, and can also be connected to the first IAB host or the second IAB host through at least one intermediate IAB node.

[0195] For example, Fig. 7A As shown, IAB node 1 is directly connected to IAB host 1 before switching, and IAB node 1 is directly connected to IAB host 2 after switching. The first IAB node in the second scenario may refer to Fig. 7A IAB node 1 in the.

[0196] For another example, IAB node 2 is connected to IAB host 1 through a two-hop wireless backhaul link (via IAB node 1) before IAB node 1 switches, and IAB node 2 is connected to IAB host 2 through a two-hop wireless backhaul link (via IAB node 1) after IAB node 1 switches. The first IAB node in scenario 2 may refer to Fig. 7A IAB node 2 in the.

[0197] For example, Figure 7BAs shown, before the handover, IAB node 4 is connected to the DU of IAB host 1 through a three-hop wireless backhaul link (via IAB node 1 and IAB node 2), and after the handover, IAB node 4 is connected to the DU of IAB host 2 through a two-hop wireless backhaul link (via IAB node 3). The first IAB node in this scenario 2 may refer to Figure 7B IAB node 4 in.

[0198] Combined with the previous description, such as Figure 8 FIG. 1 is a flow chart of a second communication method provided in an embodiment of the present application. Figure 8 , the method comprises the following steps.

[0199] Step 801: A CU of a first IAB host sends a first message to a CU of a second IAB host. The first message includes an identifier of a first IAB node, and the first message is used to request a first address.

[0200] The first IAB node is connected to the CU of the first IAB host before switching, and is connected to the CU of the second IAB host after switching. In other words, the first IAB host is the CU of the source IAB host of the first IAB node, and the second IAB host is the CU of the target IAB host of the first IAB node.

[0201] It should be noted that, in a state where the DU and CU of the IAB host are not separated, the above step 801 can be replaced by: the first IAB host sends a first message to the second IAB host. The first message includes an identifier of the first IAB node, and the first message is used to request a first address. The first IAB node is connected to the first IAB host before switching, and is connected to the second IAB host after switching.

[0202] In a possible implementation, the first message may be a HANDOVER REQUEST message, wherein, optionally, the HANDOVER REQUEST message includes a context of a user plane of an F1 interface and / or a control plane connection of an F1 interface between the first IAB host CU and the first IAB node, and an identifier of the first IAB node (e.g., a gNB DU ID configured in the DU part of the first IAB node). Optionally, the context information of the F1 interface control plane also includes TNL coupling information that carries the F1 interface control plane message.

[0203] Step 802: The CU of the second IAB host sends a second message to the CU of the first IAB host. The second message includes a first IP address allocated to the first IAB node.

[0204] It should be noted that, in a state where the DU and the CU of the IAB host are not separated, the above step 802 may be replaced by: the second IAB host sends a second message to the first IAB host.

[0205] In a possible embodiment, the second message may be a HANDOVER REQUESTACKNOWLEDGE message, which may include the first IP address allocated by the CU of the second IAB host to the first IAB node. Optionally, the second message may also include the transport network layer address information of the CU of the second IAB host (or specifically, the CU-CP of the second IAB host), which is used for the first IAB node to establish a TNL coupling with the CU of the second IAB host.

[0206] In a possible embodiment, the first IP address may be obtained by the CU of the second IAB host from the IP address pool of the CU of the second IAB host, or obtained by the CU of the second IAB host from the DU of the second IAB host, or obtained by the CU of the second IAB host from the operation and maintenance management entity OAM, or obtained by the CU of the second IAB host from the DHCP server.

[0207] Step 803: The CU of the first IAB host sends a third message to the first IAB node.

[0208] In a possible case, when the DU and CU of the IAB host are not separated, the above step 803 may be replaced by: the first IAB host sends a third message to the first IAB node.

[0209] In one possible case, if the CU of the first IAB host is in a form where the control plane and the user plane are separated, the CU of the first IAB host in step 803 may be specifically replaced by the CU-CP of the first IAB host for understanding.

[0210] The third message is used to instruct the first IAB node to switch the connection to the cell served by the second parent node. In a possible case, when the DU and CU of the IAB host are not separated, the first parent node is the first IAB host, or the first parent node is the second IAB node connected to the first IAB host; the second parent node is the second IAB host, or the second parent node is the third IAB node connected to the second IAB host.

[0211] In one possible case, when the DU and CU of the IAB host are separated, the parent node to which the first IAB node is currently connected is the first parent node, the first parent node is the DU of the first IAB host, or the first parent node is the second IAB node connected to the CU of the first IAB host through the DU of the first IAB host, the second parent node is the DU of the second IAB host, or the second parent node is the third IAB node connected to the CU of the second IAB host through the DU of the second IAB host.

[0212] For example, the first IAB node is Fig. 7A IAB node 1 in the first parent node is Fig. 7A The second parent node can be the DU of IAB host 1 connected to IAB node 1. Fig. 7A The DU of the IAB host 2 to which the IAB node 1 is connected.

[0213] For example, the first IAB node is Fig. 7A IAB node 2 in the first parent node is Fig. 7A The IAB node 1 connected to IAB node 2 in the example has a second parent node of Fig. 7A In other words, the first parent node and the second parent node may be the same, but since the IAB node 1 switches from the DU of the IAB host 1 to the DU of the IAB host 2, the cell served by the IAB node 1 may change. Therefore, although the parent node connected to the IAB node 2 before and after the switching does not change, it will actually be connected to a different serving cell after the switching.

[0214] In another example, the first IAB node is Figure 7B IAB node 4 in the first parent node is Figure 7B The second parent node is the IAB node 2 connected to the IAB node 4. Figure 7B The IAB node 4 is connected to the IAB node 3.

[0215] In a possible implementation, the third message may be a high-level radio resource control (RRC) reconfiguration message, the RRC reconfiguration message including a handover command, the handover command may be an information element specifically requiring the first IAB node to perform reconfiguration with sync. Alternatively, the third message may be carried in other RRC messages.

[0216] In a possible implementation, the third message may include a first Internet Protocol (IP) address assigned to the first IAB node. The first IP address may include at least one IP address, and each of the at least one IP address may be an (internet protocol version 4, IPv4) address, or an (internet protocol version 6, IPv6) address, or a network prefix portion of an IPv6 address. The first IP address is used for the first IAB node to communicate with the CU of the second IAB host after switching to the DU of the second IAB host.

[0217] In a possible implementation, the first message may also include an IP address of the CU of the second IAB host, where the IP address is used for the IAB node to communicate with the CU of the second IAB host on the control plane, and / or the IP address of the CU of the second IAB host is used by the IAB node to determine the first TNL coupling information between the first IAB node and the CU of the second IAB host.

[0218] Step 804: The first IAB node receives the third message, obtains the first IP address from the third message, and determines a first TNL coupling between the first IAB node and the CU of the second IAB host.

[0219] In a possible implementation, the third message may also include a transport network layer address of the CU of the second IAB host (for example, an IP address of the CU of the second IAB host), where the IP address is used for control plane communication between the first IAB node and the CU of the second IAB host, and / or, the IP address of the CU of the second IAB host is used by the IAB node to determine the first TNL coupling information between the first IAB node and the CU of the second IAB host.

[0220] Optionally, before executing step 804, the first IAB node may also receive indication information from the CU of the first IAB host, or the third message may include the indication information, which is used to indicate that the first IAB node determines that the timing of the first TNL coupling information occurs after the first IAB node switches to the DU of the second IAB host.

[0221] Step 805: The first IAB node performs a switch according to the third message, switching from the DU connected to the first IAB host to the DU connected to the second IAB host.

[0222] Specifically, the first IAB node may initiate random access in the cell served by the second parent node. After receiving a response message from the second parent node, the first IAB node may continue to perform subsequent access steps to complete access to the cell served by the second parent node.

[0223] Step 806: The first IAB node determines first TNL coupling information between the first IAB node and the CU of the second IAB host according to the first IP address and / or the IP address of the CU of the second IAB host.

[0224] In a possible implementation, the first IAB node may use the first IP address and the IP address of the CU of the second IAB host to initiate a first TNL coupling establishment process to the CU of the second IAB host, establish a first TNL coupling between the first IAB node and the CU of the second IAB host, and generate corresponding first TNL coupling information.

[0225] Step 807: The first IAB node updates the context information of the control plane of the F1 interface with the first TNL coupling information. The F1 interface is an interface between the first IAB node and the CU of the second IAB host.

[0226] In a possible embodiment, the first IAB node may delete the existing IP address corresponding to the first TNL coupling in the context information of the control plane of the F1 interface, and then add the first IP address to the IP address set corresponding to the first TNL coupling, thereby generating the first TNL coupling information.

[0227] In another possible embodiment, the first IAB node may add a newly established first TNL association information in the context information of the control plane of the F1 interface, where the first TNL association information includes the first TNL association and the first IP address, that is, the first TNL association is used as one of the TNL associations for carrying the F1 interface control plane message between the first IAB node and the CU of the IAB host.

[0228] Optionally, step 807 also includes: the first IAB node uses the first TNL coupling bearer to send an F1AP message to the CU of the second IAB host, which carries the identifier of the first IAB node (for example, the gNB DUID of the DU part of the first IAB node). The F1AP message can specifically be, for example, a gNB-DU CONFIGURATION UPDATE (DU configuration update) message, or an F1 SETUP REQUEST (F1 interface setup request) message.

[0229] Step 808: The CU of the second IAB host updates the context information of the control plane of the F1 interface using the first TNL coupling information. The F1 interface is the interface between the first IAB node and the CU of the second IAB host.

[0230] In a possible embodiment, the CU of the second IAB host finds the control plane context information of the F1 interface corresponding to the identifier of the first IAB node from the F1 interface control plane context information obtained in step 801 according to the identifier of the first IAB node carried in the F1AP message sent by the first IAB node, and then the CU of the second IAB host can delete the existing TNL coupling information of the control plane context information, and then add the first TNL coupling information.

[0231] In another possible embodiment, the CU of the second IAB host finds the control plane context information of the F1 interface corresponding to the identifier of the first IAB node from the F1 interface control plane context information acquired in step 801 based on the identifier of the first IAB node carried in the first message sent by the CU of the first IAB host. The CU of the second IAB host may add the first TNL coupling information to the control plane context information of the F1 interface, where the first TNL coupling information is used to describe the first TNL coupling, that is, to use the first TNL coupling as one of the TNL couplings for carrying the F1 interface control plane message between the first IAB node and the CU of the IAB host.

[0232] Fig. 9 In the embodiment of the present application, Fig. 7A The example of switching the IAB node 1 from the IAB host 1 to the IAB host 2 is used for explanation, and the specific steps include the following steps.

[0233] Step 901: IAB node 1 sends a measurement report to the CU of the currently connected IAB host 1.

[0234] Step 902: The CU of the IAB host 1 determines to hand over the IAB node 1 to the cell served by the IAB host 2. The CU of the IAB host 1 sends a first message to the CU of the IAB host 2, such as a HANDOVER REQUEST message.

[0235] The switching request message includes the context of the user plane and control plane connection of the F1 interface between the CU of the IAB host 1 and the IAB node 1, as well as the identifier of the IAB node 1 (for example, the gNB DU ID configured by the DU of the IAB node 1).

[0236] In a possible embodiment, the context information of the F1 interface control plane also includes context information related to the TNL coupling information that carries the F1 interface control plane. The context related to the TNL coupling information may include the transmission network layer address information corresponding to the TNL coupling information; for one or a pair of transmission network layer address information, the context related to the TNL coupling information may also include the purpose of the TNL coupling information, and the purpose of the TNL coupling information mainly refers to whether it is used to carry UE-related F1AP signaling or non-UE-related F1AP signaling. If the purpose of the TNL coupling information is to carry UE-related F1AP signaling, the context may also include the UE identifier (the UE here may be a UE accessing a cell served by IAB node 1, or a child node of IAB node 1). , wherein one or a pair of transmission network layer address information includes the transmission network layer address information of the CU of the first IAB host, and / or the transmission network layer address information of the first IAB node).

[0237] Optionally, this embodiment of the present application further includes step 903.

[0238] Step 903: If IAB node 1 will be switched through the second parent node (i.e. Fig. 7A If the DU of IAB host 2 in the IAB host is connected to the CU of IAB host 2, the CU of IAB host 2 can also send an F1AP message (specifically, UE CONTEXT SETUP REQUEST) to the second parent node after the IAB node 1 is switched, to establish the context information of IAB node 1 at the target parent node (the second parent node). After that, the second parent node (DU of IAB host 2) will send a context establishment response message (specifically, UE CONTEXT SETUP RESPONSE) to the CU of IAB host 2.

[0239] Step 904 : The CU of the IAB host 2 sends a second message to the CU of the IAB host 1 . The second message may be, for example, a HANDOVER REQUEST ACKNOWLEDGE message, which may include the first IP address allocated by the CU of the IAB host 2 to the IAB node 1 .

[0240] Optionally, the handover request confirmation message may further include transport network layer address information of the CU of the IAB host 2 (specifically, the CU-CP of the IAB host 2 ), which is used for the IAB node 1 to establish TNL coupling information with the CU of the IAB host 2 .

[0241] Optionally, the second message may also include other configuration information sent to the IAB node 1, including any one or more of the following: an adaptation layer identifier (BAP address) assigned by the CU of the IAB host 2 to the IAB node 1, one or more uplink BAP routing identifiers (BAProuting IDs) available to the IAB node 1 in the network served by the CU of the IAB host 2, an identifier of the next hop node corresponding to each uplink BAP routing identifier (i.e., the second parent node after the IAB node 1 switches to the CU of the IAB host 2), a default BH RLC channel identifier (BH RLC channel ID) for transmitting uplink services on the link between the IAB node 1 and the second parent node, and a mapping relationship between the F1-C (F1 interface control plane) signaling type or non-F1 service type of the IAB node 1 and the BH RLC channel between the IAB node 1 and the second parent node.

[0242] Optionally, step 905 may be further included, in which the CU of the IAB host 1 sends an F1AP message (for example, a GNB-CU CONFIGURATION UPDATE message) to the IAB node 1, which includes at least one of the following: (1) TNL association information to be removed, (2) TNL association information to be added, and (3) TNL association information to be updated. Each of these three information may include one or more items.

[0243] (1) The transport network layer address information included in each item of the TNL association information to be removed is the transport network layer address information used by the TNL association currently established between the DU of the IAB node 1 and the CU of the IAB host 1. It should be noted that if the TNL association information to be removed is included, the IAB node 1 needs to perform the corresponding removal operation before step 908. The transport network layer address information included in each item of the TNL association information to be removed may refer to the transport network layer address information of the CU of the IAB host 1, and optionally, may also include the transport network layer address information of the DU part of the IAB node 1.

[0244] (2) The TNL association information to be added is the TNL association information established by the IAB node 1 through the new path after the switching is completed. The transmission network layer address information contained in each item of the information (including the transmission network layer address information of the CU of the IAB host 2, and may also include the transmission network layer address information allocated by the CU of the IAB host 2 to the DU part of the IAB node 1) is the transmission network layer address information to be used on the new path. Corresponding to this information, optionally, the message also includes a specific indication information, which is used to indicate that the TNL association indicated by the corresponding information needs to be added after the IAB node 1 switches to the second parent node. In this application, the transmission network layer address information of a node can be the IP address of the node, or the IP address and the transport layer port number of the node. For example, if the IAB node 1 sends an RRC reconfiguration completion message to the CU of the second IAB host, it means that the first IAB node switches to the second parent node.

[0245] (3) TNL association information to be updated, including one or more TNL association lists to be updated, each of which includes the transport network layer address information of the CU of the IAB host 2 and the usage indication of the TNL association, which will be used to overwrite the corresponding information corresponding to the existing TNL association between the IAB node 1 and the CU of the IAB host 1. When the CU of the IAB host 2 is in a form of CP and UP separation, the transport network layer address of the CU of the IAB host 2 mentioned in this embodiment can specifically be the transport network layer address of the CU CP of the IAB host 2.

[0246] Optionally, step 906 is also included, in which the IAB node 1 feeds back an F1AP message to the CU of the IAB host 1, which may be a GNB-CU CONFIGURATION UPDATE ACKNOWLEDGE (CU configuration update confirmation) message. The content of the message may refer to the current 3GPP protocol (i.e., 3GPP TS 38.473), but does not include the TNL coupling information to be established between the IAB node 1 and the CU of the IAB host 2 according to the information in step 905.

[0247] It should be noted that step 906 is an optional step, and step 906 is executed when step 905 is executed.

[0248] Step 907 : The CU of the IAB host 1 sends a third message to the IAB node 1 , such as an RRC reconfiguration message, wherein the RRC reconfiguration message includes a handover command, and the handover command is used to instruct the IAB node 1 to handover to the cell served by the IAB host 2 .

[0249] Optionally, the RRC reconfiguration message further includes at least one first IP address configured by the CU of the IAB host 2 for the IAB node 1, and each of the at least one first IP address is an address related to the DU of the IAB host 2 to which the IAB node 1 is connected after the switching. Optionally, the RRC reconfiguration message may also include an IP address of the CU of the IAB host 2, which can be used for the IAB node 1 to communicate with the CU of the IAB host 2 on the control plane on the new path after the switching.

[0250] Optionally, the third message may also include other configuration information sent to the IAB node 1, including any one or more of the following: an adaptation layer identifier (BAP address) assigned by the CU of the IAB host 2 to the IAB node 1, one or more uplink BAP routing identifiers (BAProuting IDs) available to the IAB node 1 in the network served by the CU of the IAB host 2, an identifier of the next hop node corresponding to each uplink BAP routing identifier (i.e., the second parent node after the IAB node 1 switches to the CU of the IAB host 2), a default BH RLC channel identifier (BH RLC channel ID) for transmitting uplink services on the link between the IAB node 1 and the second parent node, and a mapping relationship between the F1-C (F1 interface control plane) signaling type or non-F1 service type of the IAB node 1 and the BH RLC channel between the IAB node 1 and the second parent node.

[0251] Step 908, the IAB node 1 initiates a random access request in the cell served by the DU of the IAB host 2, and after completing the access, connects to the CU of the IAB host 2 through the DU of the IAB host 2.

[0252] Optionally, the embodiment of the present application also includes step 909, if the IAB node 1 is connected to the CU of the IAB host 2 through at least one hop wireless backhaul link, the CU of the IAB host 2 sends a message to perform routing configuration on the intermediate nodes that the IAB node 1 passes through on the new path, and these intermediate nodes may include the DU of the IAB host 2, and may also include other IAB nodes on the transmission path between the DU of the IAB node 1 and the IAB host 2. The content of the routing configuration of the intermediate node includes one or more downlink routing items related to the IAB node 1, and may also include one or more uplink routing items related to the IAB node 1. Among them, the downlink routing item related to the IAB node 1 includes the routing information of the IAB node 1 and the corresponding next hop node. The routing information of the IAB node 1 can be an adaptation layer routing identifier (BAP routing ID), which is composed of the BAP layer identifier (BAPaddress) of the IAB node 1 and the path identifier (BAP path ID), wherein the path identifier is optional content, which is used to indicate the transmission path between the IAB host and the IAB node 1. The uplink routing item related to IAB node 1 includes the routing information of IAB host 2 and the corresponding next-hop node. The routing information of IAB host 2 can be an adaptation layer routing identifier, which is composed of the BAP layer identifier and path identifier of IAB host 2, wherein the path identifier is optional content and is used to indicate the transmission path between IAB node 1 and IAB host. The IAB host 2 in this step can be specifically understood as the DU of IAB host 2, or the CU of IAB host 2 when the IAB host is a CU-DU separation structure. For the second parent node of IAB node 1 on the new path, the content of the routing configuration can also include the adaptation layer identifier (BAP address) of IAB node 1.

[0253] Step 910: The CU of the IAB host 2 sends a message to perform routing configuration on the IAB node 1. The content includes one or more uplink routing items related to the IAB node 1. The specific description of the content of each uplink routing item can be understood by referring to the description in step 909.

[0254] In step 911, the IAB node 1 uses the newly configured first IP address to establish a first TNL association with the CU 2 of the IAB host (specifically, it may also be the CU-CP of the CU 2 of the IAB host), and the first TNL association is established according to the transport network layer address information in the TNL association information to be added or updated provided by the CU 2 of the IAB host in step 905. Or it is established according to the IP address provided by the CU 2 of the IAB host in step 907.

[0255] Step 912: The CUs of the IAB node 1 and the IAB host 2 update the TNL coupling information.

[0256] Specifically, IAB node 1 sends an uplink F1AP message to the CU of IAB host 2, which may be a GNB-DUCONFIGURATION UPDATE message or an F1 connection establishment request (F1 SETUP REQUEST) message, which carries the gNB DU ID of IAB node 1. IAB node 1 uses the newly established first TNL coupling to carry the F1AP message.

[0257] In addition, after the CU of the IAB host 2 receives the first uplink F1AP message of the IAB node 1, it can find the context information of the IAB node 1 on the F1 interface control plane previously received from the CU of the IAB host 1 according to the gNB DUID, and replace the second TNL coupling information used to carry the F1 interface control plane message between the IAB node 1 in the context information with the relevant information of the newly established first TNL coupling (including, for example, the IP address set corresponding to the endpoints of the first TNL coupling, which can specifically be the transmission network layer address of the CU2 of the IAB host and / or the transmission network layer address of the IAB node 1), and when the F1AP message between the two is subsequently transmitted, it is transmitted through the newly established first TNL coupling.

[0258] In an embodiment of the present application, when the parent node of the first IAB node is switched due to an IAB topology update, the first IAB node obtains a first IP address, and based on the first IP address, completes the update of the control plane context between the IAB node and the second IAB host, thereby avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface. After the switching is completed, the IAB node obtains the first IP address and communicates with the CU of the second IAB host through the F1 interface, so that the IAB node can use the first IP address to communicate with the CU of the second IAB host as soon as possible after the switching is completed, thereby reducing the impact of service delays on the terminal device served by the IAB node. Embodiment 3

[0259] Scenario three, in an embodiment of the present application, the first IAB node switches from the first DU of the IAB host to the second DU of the IAB host within the service scope of the CU of the same IAB host, that is, the DU of the connected IAB host before and after the switching is different, but the CU of the connected IAB host is the same, and the first IAB node and the CU of the IAB host update the F1 interface user plane context during the switching process.

[0260] like Fig.10 , which is a flow chart of the third communication method provided by an embodiment of the present application. The method is applicable to the case where the first IAB node switches within the IAB host. Specifically, the IAB host includes the CU of the IAB host, the first DU of the IAB host, and the second DU of the IAB host. The first IAB node switches from the first DU of the IAB host to the second DU of the IAB host within the service range of the CU of the same IAB host, that is, the DUs of the IAB host connected before and after the switching are different. Fig.10 , the method comprises the following steps.

[0261] Step 1001: A first IAB node sends a first control plane message to an IAB host CU, where the first control plane message includes a first IP address and a second IP address.

[0262] Among them, the first control plane message can be an F1AP message, the first IP address is the IP address of the first IAB node used when the first IAB node communicates with the IAB host CU through the first parent node; the second IP address is the IP address of the first IAB node used when the first IAB node communicates with the IAB host CU through the second parent node; wherein the first parent node is the first DU of the IAB host, or the first parent node is the second IAB node connected to the CU of the IAB host through the first DU of the IAB host; the second parent node is the second DU of the IAB host, or the second parent node is the third IAB node connected to the CU of the IAB host through the second DU of the IAB host.

[0263] Step 1002: The IAB host CU replaces the first IP address in the downlink tunnel endpoint information of the user plane of the F1 interface between the IAB host CU and the first IAB node maintained by the IAB host CU with the second IP address;

[0264] The CU of the IAB host, the first DU of the IAB host and the second DU of the IAB host are functional entities of the same IAB host, and the F1 interface is an interface between the first IAB node and the CU of the IAB host.

[0265] It should be noted that step 1002 occurs after the first IAB node is switched from the first parent node to the second parent node.

[0266] Optionally, the embodiment of the present application may further include step 1003, the IAB host CU sends a second control plane message to the IAB node, where the control plane message includes the third IP address and the fourth IP address.

[0267] The second control plane message may be a downlink F1AP message. The third IP address is the IP address of the IAB host CU used when the first IAB node communicates with the IAB host CU through the first parent node; the fourth IP address is the IP address of the IAB host CU used when the first IAB node communicates with the IAB host CU through the second parent node; wherein the first parent node is the first DU of the IAB host, or the first parent node is the second IAB node connected to the CU of the IAB host through the first DU of the IAB host; the second parent node is the second DU of the IAB host, or the second parent node is the third IAB node connected to the CU of the IAB host through the second DU of the IAB host.

[0268] Step 1004: the first IAB node replaces the third IP address in the uplink tunnel endpoint information of the user plane of the F1 interface between the first IAB node and the IAB host CU maintained by the first IAB node with the fourth IP address;

[0269] It should be noted that the above step 1004 is an optional step, and step 1004 is performed only after step 1003 is performed. Step 1004 occurs after the first IAB node is switched from the first parent node to the second parent node. The specific switching scenario and switching method of the first IAB node switching from the first parent node to the second parent node can refer to Example 1.

[0270] In addition, it should be noted that the above method can also execute step 1003 and step 1004 first, and then execute step 1001 and step 1002.

[0271] In an embodiment of the present application, in an embodiment of the present application, when the IAB topology update causes the parent node of the first IAB node to switch, the first IAB node completes the update of the user plane context between the IAB node and the IAB host based on the obtained third IP address and fourth IP address, avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface. Embodiment 4

[0272] The same scenario as scenario 3 applies to the scenario where the CU in the IAB host is separated from the control plane and the user plane, such as Fig.11A FIG. 1 is a flow chart of a fourth communication method provided in an embodiment of the present application. Fig. 11B , the method comprises the following steps.

[0273] Step 1101: The IAB host CU-CP sends a control plane message to the CU-UP of the IAB host, where the control plane message includes a first IP address and a second IP address.

[0274] Optionally, the control plane message is an E1 interface application protocol (E1 Application, E1AP) message between the IAB host CU-CP and the IAB host CU-UP.

[0275] The first IP address is the IP address of the first IAB node used when the first IAB node communicates with the IAB host CU-UP through the first parent node; the second IP address is the IP address of the first IAB node used when the first IAB node communicates with the IAB host CU-UP through the second parent node; the first parent node is the first DU of the IAB host, or the first parent node is the second IAB node connected to the CU-UP of the IAB host through the first DU of the IAB host, the second parent node is the second DU of the IAB host, or the second parent node is the third IAB node connected to the CU-UP of the IAB host through the second DU of the IAB host.

[0276] Optionally, in the above step 1101, the control plane message sent between the IAB host CU-CP and the CU-UP of the IAB host may directly include the tunnel information of one or more second F1-U interfaces, and may also include the first tunnel information corresponding to each second F1-U interface tunnel information, or the DRB information of the UE corresponding to each second F1-U interface tunnel information. Among them, the tunnel information of the first F1-U interface is the tunnel information of the F1-U interface transmitted between the first IAB node and the IAB host CU-UP through the first parent node; the tunnel information of the second F1-U interface is the tunnel information of the F1-U interface transmitted between the first IAB node and the IAB host CU-UP through the second parent node. The tunnel information of each F1-U interface consists of an IP address + a GTP tunnel endpoint identifier (TEID). The DRB information of the UE corresponding to each second F1-U interface tunnel information may include the identifier of the UE and the identifier of the DRB of the UE.

[0277] Step 1102: The IAB host CU-UP replaces the first IP address in the downlink tunnel endpoint information of the user plane of the F1 interface with the second IP address.

[0278] In an embodiment of the present application, when the IAB topology update causes the parent node of the first IAB node to switch, the CU-UP of the second IAB host completes the update of the user plane context between the IAB node and the IAB host based on the obtained first IP address and the second IP address, thereby avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface. Embodiment 5

[0279] Scenario 5, in an embodiment of the present application, the first IAB node switches between different IAB hosts, that is, the IAB hosts connected before and after the switching are different, and the CUs of the first IAB node and the second IAB host update the F1 interface user plane context during the switching process.

[0280] like Fig. 12A As shown, it is a flowchart of the fifth communication method provided in an embodiment of the present application. This method can be applicable to the situation where the IAB hosts before and after the switching of the first IAB node are different. Specifically, when the IAB host is DU and CU are not separated, the first IAB node switches from the first IAB host to the second IAB host, that is, the IAB hosts connected before and after the switching are different; or when the IAB host is DU and CU are separated, that is, the first IAB host includes CU and DU, and the second IAB host includes CU and DU. The first IAB node switches from the DU of the first IAB host to the DU of the second IAB host, that is, the IAB hosts connected before and after the switching are different. See. Fig. 12A , the method comprises the following steps.

[0281] Step 1201a: The first IAB node sends a first control plane message to the CU of the second IAB host, where the first control plane message includes a first IP address and a second IP address.

[0282] Among them, the first control plane message can be an F1AP message, the first IP address is the IP address of the first IAB node used when the first IAB node communicates with the CU of the first IAB host through the first parent node; the second IP address is the IP address of the first IAB node used when the first IAB node communicates with the CU of the second IAB host through the second parent node; wherein the first parent node is the DU of the first IAB host, or the first parent node is the second IAB node connected to the CU of the first IAB host through the DU of the first IAB host; the second parent node is the DU of the second IAB host, or the second parent node is the third IAB node connected to the CU of the second IAB host through the DU of the second IAB host.

[0283] Step 1202a: The CU of the second IAB host replaces the first IP address in the downlink tunnel endpoint information of the user plane of the F1 interface between the CU and the first IAB node maintained by the CU with the second IP address.

[0284] The F1 interface is an interface between the first IAB node and the CU of the second IAB host.

[0285] The specific switching scenario and switching method of the first IAB node switching from the CU of the first IAB host to the CU of the second IAB host can refer to the first embodiment.

[0286] In an embodiment of the present application, when the IAB topology update causes the parent node of the first IAB node to switch, the CU of the second IAB host completes the update of the user plane context between the IAB node and the IAB host based on the obtained first IP address and the second IP address, thereby avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface.

[0287] like Fig. 12B As shown, it is a flow chart of the sixth communication method provided in an embodiment of the present application. This method is also applicable to the situation where the IAB hosts before and after the switching of the first IAB node are different. Specifically, when the IAB host is DU and CU are not separated, the first IAB node switches from the first IAB host to the second IAB host, that is, the IAB hosts connected before and after the switching are different; or when the IAB host is DU and CU are separated, that is, the first IAB host includes CU and DU, and the second IAB host includes CU and DU. The first IAB node switches from the DU of the first IAB host to the DU of the second IAB host, that is, the IAB hosts connected before and after the switching are different. See. Fig. 12B , the method comprises the following steps.

[0288] Step 1201b: The CU of the first IAB host sends a second control plane message to the first IAB node, where the second control plane message includes the third IP address and the fourth IP address, wherein the fourth IP address may be obtained by the CU of the first IAB host from the CU of the second IAB host.

[0289] That is, before the first IAB node switches to the CU of the second IAB host, the first IAB node may obtain the third IP address and the fourth IP address from the CU of the first IAB host.

[0290] Optionally, the above step 1201b may also be: the CU of the second IAB host sends the second control plane to the first IAB node. That is, after the first IAB node switches to the CU of the second IAB host, the first IAB node may obtain the third IP address and the fourth IP address from the CU of the second IAB host.

[0291] The second control plane message may be an F1AP message. The third IP address is an IP address of a CU of the first IAB host used when the first IAB node communicates with the CU of the first IAB host through the first parent node; the fourth IP address is an IP address of a CU of the second IAB host used when the first IAB node communicates with the CU of the second IAB host through the second parent node.

[0292] Step 1202b: The first IAB node replaces the third IP address in the uplink tunnel endpoint information of the user plane of the F1 interface between the first IAB node and the CU of the second IAB host with the fourth IP address.

[0293] In addition, it should be noted that the above method can also execute step 1203 and step 1204 first, and then execute step 1201 and step 1202.

[0294] In an embodiment of the present application, in an embodiment of the present application, when the IAB topology update causes the parent node of the first IAB node to switch, the first IAB node completes the update of the user plane context between the IAB node and the IAB host based on the obtained third IP address and fourth IP address, avoiding service delays and signaling overhead caused by the reconstruction of the F1 interface.

[0295] With respect to the above-mentioned embodiments 1 to 5, it should be noted that: (1) the above-mentioned embodiments 1 and 5 can be implemented separately in different scenarios, or can be implemented in combination in the same scenario, or different schemes involved in different embodiments can be implemented in combination (for example, part or all of the schemes involved in embodiment 1 can be implemented in combination with embodiment 3), without specific limitation.

[0296] (2) The step numbers of the flowcharts described in the embodiments of the present application are merely examples of the execution process and do not constitute a limitation on the order of execution of the steps. There is no strict execution order between the steps that have no time dependency on each other in the embodiments of the present application.

[0297] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of the interaction between the network device and the terminal device. It is understandable that in order to achieve the above functions, the network device or the terminal device may include a hardware structure and / or software module corresponding to the execution of each function. It should be easily appreciated by those skilled in the art that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the embodiments of the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0298] The embodiment of the present application can divide the terminal device and the network device into functional units according to the above method example. For example, each functional unit can be divided according to each function, or two or more functions can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of software functional units.

[0299] In the case of an integrated unit, Fig.13 A possible exemplary block diagram of the device involved in the embodiments of the present application is shown. Fig.13 As shown, the apparatus 1300 may include: a processing unit 1302 and a communication unit 1303. The processing unit 1302 is used to control and manage the actions of the apparatus 1300. The communication unit 1303 is used to support the communication between the apparatus 1300 and other devices. Optionally, the communication unit 1303 is also called a transceiver unit, and may include a receiving unit and / or a sending unit, which are respectively used to perform receiving and sending operations. The apparatus 1300 may also include a storage unit 1301, which is used to store program codes and / or data of the apparatus 1300.

[0300] The device 1300 may be the first IAB node in any of the above embodiments, or may be a chip set in the first IAB node. The processing unit 1302 may support the device 1300 to perform the actions of the first IAB node in each method example above. Alternatively, the processing unit 1302 mainly performs the internal actions of the first IAB node in the method example, and the communication unit 1303 may support the communication between the device 1300 and the network device (e.g., the CU of the IAB host). For example, the communication unit 1303 may be used to perform Figure 5 Step 502.

[0301] The device 1300 may be a network device in any of the above embodiments (such as a CU or an IAB host of the IAB host in the above embodiments), or may be a chip set in the network device. The processing unit 1302 may support the device 1300 to perform the actions of the network device in each method example above. Alternatively, the processing unit 1302 mainly performs the internal actions of the network device in the method example, and the communication unit 1303 may support the communication between the device 1300 and the first IAB node. For example, the processing unit 1302 may be used to perform the internal actions of the IAB host in the method example; the communication unit 1303 may be used to perform Figure 5 Step 501.

[0302] It should be understood that the division of the units in the above device is only a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or they can be physically separated. And the units in the device can all be implemented in the form of software calling through processing elements; they can also be all implemented in the form of hardware; some units can also be implemented in the form of software calling through processing elements, and some units can be implemented in the form of hardware. For example, each unit can be a separately established processing element, or it can be integrated in a certain chip of the device. In addition, it can also be stored in the memory in the form of a program, and called and executed by a certain processing element of the device. The function of the unit. In addition, all or part of these units can be integrated together, or they can be implemented independently. The processing element described here can also be a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each unit above can be implemented by an integrated logic circuit of hardware in the processor element or in the form of software calling through a processing element.

[0303] In one example, the unit in any of the above devices may be one or more integrated circuits configured to implement the above method, such as one or more application specific integrated circuits (ASIC), or one or more digital singnal processors (DSP), or one or more field programmable gate arrays (FPGA), or a combination of at least two of these integrated circuit forms. For another example, when the unit in the device can be implemented in the form of a processing element scheduler, the processing element can be a processor, such as a general-purpose central processing unit (CPU), or other processors that can call programs. For another example, these units can be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0304] The above unit for receiving is an interface circuit of the device, which is used to receive signals from other devices. For example, when the device is implemented in the form of a chip, the receiving unit is an interface circuit of the chip used to receive signals from other chips or devices. The above unit for sending is an interface circuit of the device, which is used to send signals to other devices. For example, when the device is implemented in the form of a chip, the sending unit is an interface circuit of the chip used to send signals to other chips or devices.

[0305] Please refer to Fig.14 , which is a schematic diagram of the structure of an IAB node provided in an embodiment of the present application. It can be the IAB node in the above embodiment, and is used to implement the operation of the IAB node in the above embodiment. Fig.14 As shown, the IAB node includes: an antenna 1410, a radio frequency part 1420, and a signal processing part 1430. The antenna 1410 is connected to the radio frequency part 1420. In the downlink direction, the radio frequency part 1420 receives information sent by the network device through the antenna 1410, and sends the information sent by the network device to the signal processing part 1430 for processing. In the uplink direction, the signal processing part 1430 processes the information of the IAB node and sends it to the radio frequency part 1420. The radio frequency part 1420 processes the information of the IAB node and sends it to the network device through the antenna 1410.

[0306] The signal processing part 1430 may include a modulation and demodulation subsystem for processing each communication protocol layer of data; and may also include a central processing subsystem for processing the IAB node operating system and application layer.

[0307] The modem subsystem may include one or more processing elements 1431, for example, a main control CPU and other integrated circuits. In addition, the modem subsystem may also include a storage element 1432 and an interface circuit 1433. The storage element 1432 is used to store data and programs, but the program used to execute the method executed by the IAB node in the above method may not be stored in the storage element 1432, but stored in a memory outside the modem subsystem, and loaded and used by the modem subsystem when in use. The interface circuit 1433 is used to communicate with other subsystems.

[0308] The modem subsystem can be implemented by a chip, which includes at least one processing element and an interface circuit, wherein the processing element is used to execute each step of any method executed by the above IAB node, and the interface circuit is used to communicate with other devices. In one implementation, the unit of the IAB node implementing each step in the above method can be implemented in the form of a processing element scheduler, for example, the device for the IAB node includes a processing element and a storage element, and the processing element calls the program stored in the storage element to execute the method executed by the IAB node in the above method embodiment. The storage element can be a storage element on the same chip as the processing element, that is, an on-chip storage element.

[0309] In another implementation, the program for executing the method executed by the IAB node in the above method may be in a storage element on a different chip from the processing element, that is, an off-chip storage element. In this case, the processing element calls or loads the program from the off-chip storage element to the on-chip storage element to call and execute the method executed by the IAB node in the above method embodiment.

[0310] In another implementation, the unit of the IAB node implementing each step in the above method may be configured as one or more processing elements, which are arranged on the modem subsystem. The processing elements here may be integrated circuits, such as one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these integrated circuits. These integrated circuits may be integrated together to form a chip.

[0311] The units of the IAB node implementing the various steps in the above method can be integrated together and implemented in the form of a SOC, and the SOC chip is used to implement the above method. The chip can integrate at least one processing element and a storage element, and the processing element calls the stored program of the storage element to implement the above method executed by the IAB node; or, the chip can integrate at least one integrated circuit to implement the above method executed by the IAB node; or, the above implementation methods can be combined, and the functions of some units are implemented by the processing element calling the program, and the functions of some units are implemented by the integrated circuit.

[0312] It can be seen that the above apparatus for IAB node may include at least one processing element and an interface circuit, wherein at least one processing element is used to execute any one of the methods performed by the IAB node provided in the above method embodiments. The processing element may execute part or all of the steps performed by the IAB node in a first manner: that is, by calling a program stored in a storage element; or in a second manner: that is, by combining an integrated logic circuit of hardware in a processor element with instructions to execute part or all of the steps performed by the IAB node; of course, the first manner and the second manner may also be combined to execute part or all of the steps performed by the IAB node.

[0313] The processing element here is the same as described above and can be implemented by a processor. The function of the processing element can be Fig.13 The processing unit described in the above has the same function. Exemplarily, the processing element may be a general-purpose processor, such as a CPU, or one or more integrated circuits configured to implement the above method, such as one or more ASICs, or one or more microprocessors DSPs, or one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. The storage element may be implemented by a memory, and the function of the storage element may be the same as Fig.13 The storage element can be implemented by a memory, and the function of the storage element can be the same as that of the storage unit described in Fig.13 The storage element may be a memory or a collective name for multiple memories.

[0314] Fig.14 The IAB node shown is capable of Figure 5 , Figure 6 , Figures 8 to 12B The illustrated method embodiment involves various processes of the IAB node. Fig.14 The operations and / or functions of each module in the IAB node shown are respectively for implementing the corresponding processes in the above method embodiment. For details, please refer to the description in the above method embodiment. To avoid repetition, the detailed description is appropriately omitted here.

[0315] Please refer to Fig.15 , which is a schematic diagram of the structure of a network device provided in an embodiment of the present application. It is used to implement the operation of the network device in the above embodiment. Fig.15 As shown, the network device includes: an antenna 1501, a radio frequency device 1502, and a baseband device 1503. The antenna 1501 is connected to the radio frequency device 1502. In the uplink direction, the radio frequency device 1502 receives information sent by the terminal device through the antenna 1501, and sends the information sent by the terminal device to the baseband device 1503 for processing. In the downlink direction, the baseband device 1503 processes the information of the terminal device and sends it to the radio frequency device 1502, and the radio frequency device 1502 processes the information of the terminal device and sends it to the terminal device through the antenna 1501.

[0316] The baseband device 1503 may include one or more processing elements 15031, for example, including a main control CPU and other integrated circuits. In addition, the baseband device 1503 may also include a storage element 15032 and an interface 15033, the storage element 15032 is used to store programs and data; the interface 15033 is used to interact with the radio frequency device 1502. The interface is, for example, a common public radio interface (CPRI). The above device for the network device may be located in the baseband device 1503. For example, the above device for the network device may be a chip on the baseband device 1503, the chip includes at least one processing element and an interface circuit, wherein the processing element is used to execute each step of any method executed by the above network device, and the interface circuit is used to communicate with other devices. In one implementation, the unit for the network device to implement each step in the above method can be implemented in the form of a processing element scheduling program. For example, the device for the network device includes a processing element and a storage element, and the processing element calls the program stored in the storage element to execute the method executed by the network device in the above method embodiment. The storage element may be a storage element on the same chip as the processing element, ie, an on-chip storage element, or may be a storage element on a different chip from the processing element, ie, an off-chip storage element.

[0317] In another implementation, the unit of the network device implementing each step in the above method may be configured as one or more processing elements, which are arranged on the baseband device. The processing elements here may be integrated circuits, such as one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these integrated circuits. These integrated circuits may be integrated together to form a chip.

[0318] The units of the network device implementing the various steps in the above method can be integrated together and implemented in the form of a system-on-a-chip (SOC). For example, the baseband device includes the SOC chip to implement the above method. The chip can integrate at least one processing element and a storage element, and the method executed by the above network device can be implemented in the form of a program stored in the storage element called by the processing element; or, the chip can integrate at least one integrated circuit to implement the method executed by the above network device; or, the above implementation methods can be combined, and the functions of some units can be implemented in the form of a processing element calling a program, and the functions of some units can be implemented in the form of an integrated circuit.

[0319] It can be seen that the above apparatus for network equipment may include at least one processing element and an interface circuit, wherein at least one processing element is used to execute any one of the methods performed by the network equipment provided in the above method embodiments. The processing element may execute part or all of the steps performed by the network equipment in a first manner: that is, by calling a program stored in a storage element; or in a second manner: that is, by combining an integrated logic circuit of hardware in a processor element with instructions to execute part or all of the steps performed by the network equipment; of course, the first manner and the second manner may be combined to execute part or all of the steps performed by the above network equipment.

[0320] The processing element here is the same as described above and can be implemented by a processor. The function of the processing element can be Fig.10 The processing unit described in the above has the same function. Exemplarily, the processing element may be a general-purpose processor, such as a CPU, or one or more integrated circuits configured to implement the above method, such as one or more ASICs, or one or more microprocessors DSPs, or one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. The storage element may be implemented by a memory, and the function of the storage element may be the same as Fig.13 The storage element can be implemented by a memory, and the function of the storage element can be the same as that of the storage unit described in Fig.13 The storage element may be a memory or a collective name for multiple memories.

[0321] Fig.15 The network device shown is capable of implementing various processes involving the network device in the above method embodiments. Fig.15 The operations and / or functions of each module in the network device shown are respectively for implementing the corresponding processes in the above method embodiments. For details, please refer to the description in the above method embodiments. To avoid repetition, the detailed description is appropriately omitted here.

[0322] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0323] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0324] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0325] These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0326] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A communication method, characterized in that: include: The centralized unit CU of the access backhaul integrated IAB host receives a first control plane message from the first IAB node, wherein the first control plane message includes a first Internet interconnection protocol IP address and a second IP address, wherein the first IP address is the IP address of the first IAB node when the first IAB node communicates with the IAB host CU through a first parent node; the second IP address is the IP address of the first IAB node when the first IAB node communicates with the IAB host CU through a second parent node; wherein the first parent node is a first distributed unit DU of the IAB host or the first parent node is connected to the CU of the IAB host through a first DU of the IAB host, and the second parent node is a second DU of the IAB host or the second parent node is connected to the CU of the IAB host through a second DU of the IAB host; The IAB host CU replaces the first IP address in the downlink tunnel endpoint information of the user plane of the first interface with the second IP address; The CU of the IAB host, the first DU of the IAB host and the second DU of the IAB host are functional entities of the same IAB host, and the first interface is an interface between the first IAB node and the CU of the IAB host.

2. The method according to claim 1, characterized in that The first control plane message is an F1AP message.

3. The method according to claim 1 or 2, characterized in that: The first IAB node is switched from the first parent node to the second parent node.

4. The method according to any one of claims 1 to 3, characterized in that: The method further comprises: The CU of the IAB host sends a second control plane message to the first IAB node, where the second control plane message includes a third IP address and a fourth IP address; The third IP address is the IP address of the CU of the IAB host when the CU of the IAB host communicates with the first IAB node through the first parent node; the fourth IP address is the IP address of the CU of the IAB host when the CU of the IAB host communicates with the first IAB node through the second parent node.

5. The method according to claim 4, characterized in that The second control plane message is an F1AP message.

6. A communication method, characterized in that: include: The first access backhaul integrated IAB node sends a first control plane message to the centralized unit CU of the IAB host, wherein the first control plane message includes a first Internet interconnection protocol IP address and a second IP address; The first IP address is the IP address of the first IAB node when the first IAB node communicates with the IAB host CU through the first parent node, and the second IP address is the IP address of the first IAB node when the first IAB node communicates with the IAB host CU through the second parent node; The first parent node is a first distributed unit DU of the IAB host or the first parent node is connected to a CU of the IAB host through a first DU of the IAB host, and the second parent node is a second DU of the IAB host or the second parent node is connected to the CU of the IAB host through a second DU of the IAB host; and The CU of the IAB host, the first DU of the IAB host and the second DU of the IAB host are functional entities of the same IAB host.

7. The method according to claim 6, characterized in that The first control plane message is an F1AP message.

8. The method according to claim 6 or 7, characterized in that: The first IAB node is switched from the first parent node to the second parent node.

9. The method according to any one of claims 6 to 8, characterized in that: The method further comprises: The first IAB node receives a second control plane message from the CU of the IAB host, where the second control plane message includes a third IP address and a fourth IP address; The first IAB node replaces the third IP address in the uplink tunnel endpoint information of the user plane of the first interface with the fourth IP address; The third IP address is the IP address of the CU of the IAB host when the first IAB node communicates with the IAB host CU through the first parent node, the fourth IP address is the IP address of the CU of the IAB host when the first IAB node communicates with the IAB host CU through the second parent node, and the first interface is the interface between the first IAB node and the CU of the IAB host.

10. The method according to claim 9, characterized in that The second control plane message is an F1AP message.

11. A communication method, characterized in that: include: The first access backhaul integrated IAB node receives a control plane message from a centralized unit CU of an IAB host, wherein the control plane message includes a first Internet interconnection protocol IP address and a second IP address, wherein the first IP address is the IP address of the CU of the IAB host when the first IAB node communicates with the IAB host CU through a first parent node; and the second IP address is the IP address of the CU of the IAB host when the first IAB node communicates with the IAB host CU through a second parent node, wherein the first parent node is a first DU of the IAB host or the first parent node is connected to the CU of the IAB host through the first DU of the IAB host, and the second parent node is a second DU of the IAB host or the second parent node is connected to the CU of the IAB host through the second DU of the IAB host; The first IAB node replaces the first IP address in the uplink tunnel endpoint information of the user plane of the first interface with the second IP address; The CU of the IAB host, the first DU of the IAB host and the second DU of the IAB host are functional entities of the same IAB host, and the first interface is an interface between the first IAB node and the CU of the IAB host.

12. The method according to claim 11, characterized in that The control plane message is an F1AP message.

13. The method according to claim 11 or 12, characterized in that: The first IAB node is switched from the first parent node to the second parent node.

14. A communication method, characterized in that: include: The centralized unit CU of the access backhaul integrated IAB host sends a control plane message to the first IAB node, wherein the control plane message includes the first Internet interconnection protocol IP address and the second IP address; The first IP address is the IP address of the CU of the IAB host when the first IAB node communicates with the IAB host CU through the first parent node; the second IP address is the IP address of the CU of the IAB host when the first IAB node communicates with the IAB host CU through the second parent node; The first parent node is a first DU of the IAB host or the first parent node is connected to the CU of the IAB host through the first DU of the IAB host, and the second parent node is a second DU of the IAB host or the second parent node is connected to the CU of the IAB host through the second DU of the IAB host; and The CU of the IAB host, the first DU of the IAB host and the second DU of the IAB host are functional entities of the same IAB host.

15. The method according to claim 14, characterized in that The control plane message is an F1AP message.

16. The method according to claim 14 or 15, characterized in that: The first IAB node is switched from the first parent node to the second parent node.

17. A communication method, characterized in that: include: The CU-UP of the access backhaul integrated IAB host receives a control plane message from the CU-CP of the IAB host, wherein the control plane message includes a first Internet interconnection protocol IP address and a second IP address, wherein the first IP address is an IP address of the first IAB node when the first IAB node communicates with the CU-UP of the IAB host through a first parent node; and the second IP address is an IP address of the first IAB node when the first IAB node communicates with the CU-UP of the IAB host through a second parent node; The first parent node is a first DU of the IAB host or the first parent node is connected to a CU-UP of the IAB host through a first distributed unit DU of the IAB host, and the second parent node is a second DU of the IAB host or the second parent node is connected to the CU-UP of the IAB host through a second DU of the IAB host; The CU-UP of the IAB host replaces the first IP address in the downlink tunnel endpoint information of the user plane of the first interface with the second IP address; The first DU of the IAB host, the second DU of the IAB host, the CU-CP of the IAB host and the CU-UP of the IAB host are functional entities of the same IAB host, and the first interface is an interface between the first IAB node and the CU-UP of the IAB host.

18. The method according to claim 17, characterized in that The control plane message is an F1AP message.

19. The method according to claim 17 or 18, characterized in that: The first IAB node is switched from the first parent node to the second parent node.

20. A communication method, characterized in that: include: The CU-CP of the access backhaul integrated IAB host sends a control plane message to the CU-UP of the IAB host, wherein the control plane message includes a first Internet interconnection protocol IP address and a second IP address, wherein the first IP address is the IP address of the first IAB node when the first IAB node communicates with the CU-UP of the IAB host through the first parent node; and the second IP address is the IP address of the first IAB node when the first IAB node communicates with the CU-UP of the IAB host through the second parent node. The first parent node is a first DU of the IAB host or the first parent node is connected to a CU-UP of the IAB host through a first distributed unit DU of the IAB host, and the second parent node is a second DU of the IAB host or the second parent node is connected to the CU-UP of the IAB host through a second DU of the IAB host; The first DU of the IAB host, the second DU of the IAB host, the CU-CP of the IAB host and the CU-UP of the IAB host are functional entities of the same IAB host.

21. The method according to claim 20, characterized in that The control plane message is an F1AP message.

22. The method according to claim 20 or 21, characterized in that: The first IAB node is switched from the first parent node to the second parent node.

23. A communication device, characterized in that: The device comprises at least one processor, wherein the at least one processor is connected to a memory, and the at least one processor is used to read and execute a program stored in the memory, so that the device executes the method according to any one of claims 1 to 22.

24. A chip, characterized in that: The chip is coupled to a memory and is used to read and execute program instructions stored in the memory to implement the method according to any one of claims 1 to 22.

25. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and when the instructions are executed on a computer, the computer executes the method according to any one of claims 1 to 22.

26. A computer program product, characterized in that When the computer program product is called by a computer, it enables the computer to execute the method according to any one of claims 1 to 22.

27. A communication system, characterized in that: The communication system comprises a CU of an access backhaul integrated IAB host for executing the method according to any one of claims 1 to 5, and an IAB node for executing the method according to any one of claims 6 to 10, or, The communication system comprises an access backhaul integrated IAB node for executing the method according to any one of claims 11 to 13, and a CU of an IAB host for executing the method according to any one of claims 14 to 16; or The communication system comprises a CU-UP of an access backhaul integrated IAB host for executing the method according to any one of claims 17 to 19, and a CU-CP of an IAB host for executing the method according to any one of claims 20-22.

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