RLF recovery method, device and related equipment of IAB network

Abstract

The present application provides an RLF recovery method of an IAB network, which can be applied to the field of wireless communication technology, the method comprising: a first IAB node establishes an RRC connection with a target IAB host by performing RLF recovery; after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the first IAB node sends a first message to a second node through SRB1 or SRB2, or the first IAB node sends a BH RLF indication to the second node, and before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node. The present application can trigger the second node to establish an RRC connection with the target IAB host through the first message or the BH RLF indication, so that the connection between the second node and the target IAB host can be restored as soon as possible, thereby improving the reliability of the network connection.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technology, and in particular to an RLF recovery method, apparatus and related equipment of an IAB network. Background Art

[0002] The fifth-generation (5G) mobile communication system introduces integrated access and backhaul (IAB) network technology. Both the access link and the backhaul link in the IAB network adopt wireless transmission solutions to avoid optical fiber deployment, thereby reducing deployment costs and improving deployment flexibility.

[0003] In the IAB network, the IAB node transmits data with the core network through the source IAB host. If a radio link failure (RLF) occurs in the backhaul link of the IAB node, the IAB node will perform the RLF recovery process, that is, try to re-establish the radio resource control (RRC). During the RRC reconstruction process, the IAB node will select a suitable cell, or select a suitable IAB host for RRC re-establishment. If the IAB host selected by the IAB node is the source IAB host, then since the IAB host to which the subordinate nodes served by the IAB node are connected has not changed, the subordinate nodes do not need to perceive whether the topology of the IAB network has changed. The source IAB host can provide the subordinate nodes of the IAB node with new BAP layer routing and / or BH RLC channel mapping configuration through the new path.

[0004] However, the IAB host selected by the IAB node may not be the source IAB host. The newly selected IAB host is called the target IAB host. In this case, due to the replacement of the IAB host, the target IAB host cannot correctly encrypt and decrypt and / or perform integrity protection on the data sent by the subordinate nodes of the IAB node, resulting in service interruption of the subordinate nodes. Summary of the invention

[0005] The present application provides an RLF recovery method, apparatus and related devices of an IAB network, which can restore the connection between a second node and a target IAB host as quickly as possible and improve the reliability of the network connection.

[0006] A first aspect of the present application provides a RLF recovery method for an IAB network.

[0007] The method includes: after a first IAB node has an RLF or receives a backhaul RLF indication (BH RLF indication), the first IAB node may perform RLF recovery, and establish a radio resource control RRC connection with a target IAB host during the RLF recovery process; after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the first IAB node sends a first message to a second node through a signaling radio bearer SRB1 or SRB2, or the first IAB node sends a BH RLF indication to the second node, the first message or BHRLF indication is used to establish an RRC connection between the second node and the target IAB host, before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node. Wherein, when the second node is a subordinate UE, the subordinate UE is not a UE indirectly connected to the first IAB node through a child node.

[0008] In the present application, since the first message is sent by the first IAB node through SRB1 or SRB2, after the second node receives the first message, if the integrity protection check of the first message fails, RRC re-establishment will be triggered. Through the first message, or BH RLF indication, the second node can be triggered to establish an RRC connection with the target IAB host, so that the connection between the second node and the target IAB host can be restored as soon as possible, improving the reliability of the network connection.

[0009] In an optional implementation of the first aspect, the first message is an RRC message. Before the first IAB node sends the first message to the second node, after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the first IAB node receives a second message from the target IAB host, and the second message includes an SRB identifier and an RRC message, and the SRB identifier includes an identifier of SRB1 and / or SRB2. Among them, the target IAB host may have multiple child nodes, that is, multiple first IAB nodes. The RRC message and SRB identifier are generated by the target IAB host, and the first IAB node is responsible for forwarding the RRC message according to the SRB identifier to facilitate centralized management of RLF recovery.

[0010] In an optional implementation of the first aspect, before the first IAB node sends the first message to the second node, the first IAB node receives a second message from the target IAB host, the second message includes first indication information; the first IAB node sends a BH RLF indication to the second node according to the first indication information. The first IAB node may include multiple child nodes or subordinate UEs, that is, multiple second nodes. After receiving the first indication information, the first IAB node may send a BH RLF indication to the multiple second nodes according to the first indication information, thereby reducing signaling transmission between the first IAB node and the target IAB host.

[0011] In an optional implementation of the first aspect, before the first IAB node sends the first message to the second node, the first IAB node receives a second message from the target IAB host, and the second message includes first indication information; the first IAB node sends the first message to the second node according to the first indication information. The first IAB node may include multiple child nodes or subordinate UEs, that is, multiple second nodes. After receiving the first indication information, the first IAB node may send the first message to the multiple second nodes according to the first indication information, thereby reducing the signaling transmission between the first IAB node and the target IAB host.

[0012] In an optional implementation of the first aspect, the second message is an RRC re-establishment message. In the process of the first IAB node establishing an RRC connection with the target IAB host by executing RLF, the target IAB host sends an RRC re-establishment message to the first IAB node. By carrying the first indication information in the RRC re-establishment message, the signaling transmission between the first IAB node and the target IAB host can be reduced.

[0013] In an optional implementation of the first aspect, the first indication information is used to indicate that the RRC reestablishment performed by the first IAB node is an RRC reestablishment across IAB hosts. The second node needs to establish an RRC connection with the target IAB host only when the RRC reestablishment performed by the first IAB node is an RRC reestablishment across IAB hosts. If the first IAB node does not perceive that the RRC reestablishment performed is an RRC reestablishment across IAB hosts, the first IAB node will not actively notify the second node to establish an RRC connection with the target IAB host, thereby failing to restore the connection between the second node and the target IAB host as soon as possible.

[0014] In an optional implementation of the first aspect, before the first IAB node sends the first message or BH RLF indication to the second node, the first IAB node sends an update notification to the second node; the first IAB node broadcasts the updated physical cell identifier (PCI) of the first IAB node, and the update notification is used to instruct the second node to obtain the updated PCI, and the updated PCI is used for the second node to correctly receive the first message or BH RLF indication. Among them, the first IAB node will use the PCI to scramble the first message or BH RLF indication. If the PCI of the first IAB node changes after the first IAB node changes the IAB host, the second node cannot correctly descramble the first message or BH RLF indication with the old PCI. Therefore, the first IAB node sends an update notification to the second node, so that the second node obtains the updated PCI of the first IAB node, and uses the updated PCI to correctly receive the first message or BHRLF indication, so that the second node establishes an RRC connection with the target IAB host through the first message or BH RLF indication.

[0015] In an optional implementation manner of the first aspect, the method further includes: the first IAB node sending an update notification to the second node;

[0016] The first IAB node broadcasts the physical cell identity PCI updated by the first IAB node, and the update notification is used to instruct the second node to obtain the updated PCI, and the updated PCI is used for the second node to correctly receive the first message.

[0017] A second aspect of the present application provides an RLF recovery method for an IAB network.

[0018] The method includes: a target IAB host sends a second message to a first IAB node, the second message is used for the first IAB node to send a first message to a second node through a signaling radio bearer SRB1 or SRB2 according to the second message, or is used for the first IAB node to send a BH RLF indication to the second node, before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0019] In an optional implementation of the second aspect, the first message is an RRC message, the second message includes an SRB identifier and an RRC message, the SRB identifier includes an identifier of SRB1 and / or SRB2; after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the target IAB host sends the second message to the first IAB.

[0020] In an optional implementation of the second aspect, the second message is an RRC re-establishment message, the RRC re-establishment message includes first indication information, and the first indication information is used by the first IAB node to send a BHRLF indication to the second node according to the first indication information.

[0021] In an optional implementation manner of the second aspect, the first indication information is used to indicate that the RRC re-establishment performed by the first IAB node is an RRC re-establishment across IAB hosts.

[0022] In an optional implementation of the second aspect, the second message also includes an identifier of the second node. Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the target IAB host sends a context acquisition request to the source IAB host; the target IAB host receives a context acquisition response from the source IAB host, and the context acquisition response includes the identifier of the second node. The target IAB host may have multiple child nodes, that is, multiple first IAB nodes. The target IAB host obtains the identifier of the second node, and sends an RRC message to the second node according to the identifier of the second node, so as to facilitate the centralized management of RLF recovery.

[0023] A third aspect of the present application provides an RLF recovery method for an IAB network.

[0024] The method includes: a source IAB host receives a context acquisition request from a target IAB host;

[0025] The source IAB host sends a context acquisition response to the target IAB host, the context acquisition response including an identifier of a second node, the identifier of the second node is used by the first IAB node to send a first message to the second node according to the identifier of the second node, the first message is used by the second node to establish an RRC connection with the target IAB host, before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0026] In the present application, the second node can establish an RRC connection with the target IAB host through the first message, so that the connection between the second node and the target IAB host can be restored as soon as possible, thereby improving the reliability of the network connection.

[0027] A fourth aspect of the present application provides an RRC reconfiguration method for an IAB network.

[0028] The method includes: the target IAB host sends a first RRC reconfiguration message to the source IAB host; the target IAB host receives a third message from the source IAB host, the third message is the RRC reconfiguration message after the first RRC reconfiguration message is encrypted and / or integrity protected; the target IAB host sends the third message to the second node through the first IAB node, before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node. Wherein, because the IAB host of the second node has changed, the second node cannot directly decrypt and / or perform integrity verification on the first RRC reconfiguration message.

[0029] In the present application, the target IAB host sends the third message to the second node, which can reduce the RRC re-establishment process of the second node and improve the user experience.

[0030] In an optional implementation of the fourth aspect, the third message includes a random access-free indication, wherein the random access process of the second node can be avoided through the indication, thereby improving user experience.

[0031] In an optional implementation of the fourth aspect, the third message is a handover command. The handover command may be an RRC reconfiguration message including a synchronous reconfiguration (Reconfiguration with Sync) IE. Through the handover command, the second node may execute the handover of the RRC connection of the IAB host.

[0032] A fifth aspect of the present application provides an RRC reconfiguration method for an IAB network.

[0033] The method includes: a source IAB host receives a first RRC reconfiguration message from a target IAB host;

[0034] The source IAB host sends a third message to the target IAB host, where the third message is the RRC reconfiguration message after the first RRC reconfiguration message is encrypted and / or integrity protected. The third message is used for the second node to establish an RRC connection with the target IAB host through the first IAB node. Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0035] In an optional implementation of the fifth aspect, the third message includes an indication of free random access.

[0036] In an optional implementation of the fifth aspect, the third message is a switching command.

[0037] A sixth aspect of the present application provides a method for updating PCI.

[0038] The method includes: a first IAB node sends an update notification to a second node;

[0039] The first IAB node broadcasts the updated physical cell identifier PCI of the first IAB node, and the update notification is used to instruct the second node to obtain the updated PCI, and the updated PCI is used for the second node to correctly receive the first message, or BH RLF indication, or the third message.

[0040] The seventh aspect of the present application provides a method for updating PCI.

[0041] The method includes: a second node receiving an update notification from a first IAB node;

[0042] The second node receives, from the first IAB node according to the update notification, a physical cell identifier PCI updated by the first IAB node;

[0043] The second node receives the first message, or the BH RLF indication, or the second RRC reconfiguration message according to the updated PCI.

[0044] An eighth aspect of the present application provides an RLF recovery device for an IAB network.

[0045] The device includes: an establishment module, used to establish a radio resource control RRC connection with a target IAB host by performing RLF recovery;

[0046] A sending module is used to send a first message to a second node through a signaling radio bearer SRB1 or SRB2 after the first IAB node establishes an RRC connection with a target IAB host by performing RLF recovery, or the first IAB node sends a backhaul link radio link failure indication BH RLF indication to the second node, the first message or BH RLF indication is used to establish an RRC connection between the second node and the target IAB host, before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0047] In an optional implementation manner of the eighth aspect, the first message is an RRC message, and the apparatus further includes:

[0048] The receiving module is used to receive a second message from a target IAB host, where the second message includes an SRB identifier and an RRC message, and the SRB identifier includes an identifier of SRB1 and / or SRB2.

[0049] In an optional implementation of the eighth aspect, the device further comprises:

[0050] A receiving module, configured to receive a second message from a target IAB host, where the second message includes the first indication information;

[0051] The sending module is specifically configured to send a BH RLF indication to the second node according to the first indication information.

[0052] In an optional implementation of the eighth aspect, the second message is an RRC re-establishment message.

[0053] In an optional implementation manner of the eighth aspect, the first indication information is used to indicate that the RRC re-establishment performed by the device is an RRC re-establishment across IAB hosts.

[0054] In an optional implementation manner of the eighth aspect, the sending module is further used to send an update notification to the second node;

[0055] The device also includes:

[0056] The broadcast module is used to broadcast the updated physical cell identity PCI of the first IAB node, and the update notification is used to instruct the second node to obtain the updated PCI, and the updated PCI is used for the second node to correctly receive the first message, or BH RLFindication.

[0057] A ninth aspect of the present application provides an RLF recovery device for an IAB network.

[0058] The device includes: a sending module, which is used to send a second message to a first IAB node, where the second message is used by the first IAB node to send the first message to the second node through a signaling radio bearer SRB1 or SRB2 according to the second message, or is used by the first IAB node to send a backhaul link radio link failure indication BH RLF indication to the second node, before the first IAB node establishes an RRC connection with a target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0059] In an optional implementation manner of the ninth aspect, the first message is an RRC message, the second message includes an SRB identifier and the RRC message, and the SRB identifier includes an identifier of SRB1 and / or SRB2;

[0060] The sending module is specifically configured to send a second message to the first IAB after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery.

[0061] In an optional implementation of the ninth aspect, the second message is an RRC re-establishment message, the RRC re-establishment message includes first indication information, and the first indication information is used by the first IAB node to send a BHRLF indication to the second node according to the first indication information.

[0062] In an optional implementation manner of the ninth aspect, the first indication information is used to indicate that the RRC re-establishment performed by the first IAB node is an RRC re-establishment across IAB hosts.

[0063] In an optional implementation manner of the ninth aspect, the second message further includes an identifier of the second node;

[0064] The sending module is also used to send a context acquisition request to the source IAB host;

[0065] The device also includes:

[0066] The receiving module is configured to receive a context acquisition response from a source IAB host, where the context acquisition response includes an identifier of the second node.

[0067] A tenth aspect of the present application provides an RLF recovery device for an IAB network.

[0068] The device includes: a receiving module, configured to receive a context acquisition request from a target IAB host;

[0069] A sending module, used to send a context acquisition response to the target IAB host, the context acquisition response including an identifier of a second node, the identifier of the second node is used by the first IAB node to send a first message to the second node according to the identifier of the second node, the first message is used by the second node to establish an RRC connection with the target IAB host, before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the device through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0070] In an eleventh aspect, the present application provides an RRC reconfiguration device for an IAB network.

[0071] The device includes: a first sending module, configured to send a first RRC reconfiguration message to a source IAB host;

[0072] A receiving module, configured to receive a third message from a source IAB host, where the third message is an RRC reconfiguration message after the first RRC reconfiguration message is encrypted and / or integrity protected;

[0073] The second sending module is used to send a third message to the second node through the first IAB node. Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node. The second node is a child node or a subordinate UE of the first IAB node.

[0074] In an optional implementation of the eleventh aspect, the third message includes an indication of free random access.

[0075] In an optional implementation of the eleventh aspect, the third message is a switching command.

[0076] A twelfth aspect of the present application provides an RRC reconfiguration device for an IAB network.

[0077] The apparatus includes: a receiving module, configured to receive a first RRC reconfiguration message from a target IAB host;

[0078] A sending module is used to send a third message to the target IAB host, where the third message is the RRC reconfiguration message after the first RRC reconfiguration message is encrypted and / or integrity protected. The third message is used for the target IAB host to send the third message to the second node through the first IAB node. Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0079] In an optional implementation of the twelfth aspect, the third message includes an indication of free random access.

[0080] In an optional implementation of the twelfth aspect, the third message is a switching command.

[0081] A thirteenth aspect of the present application provides a device for updating PCI.

[0082] The device includes: a sending module, configured to send an update notification to the second node;

[0083] A broadcast module is used to broadcast the updated physical cell identifier PCI of the first IAB node, wherein the update notification is used to instruct the second node to obtain the updated PCI, and the updated PCI is used for the second node to correctly receive the first message, or the BH RLF indication, or the third message.

[0084] A fourteenth aspect of the present application provides a device for updating PCI.

[0085] The device includes: a first receiving module, configured to receive an update notification from a first IAB node;

[0086] A second receiving module, configured to receive a physical cell identifier PCI updated by the first IAB node from the first IAB node according to the update notification;

[0087] The third receiving module is used to receive the first message, or the BH RLF indication, or the third message according to the updated PCI.

[0088] In a fifteenth aspect, the present application provides a communication device, which is used to execute the method in any possible implementation of the above aspects or aspects.

[0089] A sixteenth aspect of the present application provides a communication device, which includes: a processor; the processor is used to execute the methods in the above-mentioned various aspects or any possible implementation of each aspect.

[0090] In the seventeenth aspect of the present application, a communication device is provided, which includes a processor and a memory, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program from the memory, so that the communication device executes the methods in the above-mentioned various aspects or any possible implementation methods of various aspects.

[0091] In an eighteenth aspect, the present application provides a chip, which includes a processor and a data interface, and the processor reads program instructions stored in a memory through the data interface to execute methods in the above-mentioned various aspects or any possible implementation of each aspect.

[0092] A nineteenth aspect of the present application provides an access backhaul integrated IAB network system, characterized in that the system includes a first IAB node, a second node, a source IAB host, and a target IAB host;

[0093] The first IAB node is used to perform the first aspect or any optional method of the first aspect;

[0094] The target IAB host is used to perform the second aspect or any optional method of the second aspect;

[0095] The source IAB host is used to execute the third aspect or any optional method of the third aspect.

[0096] The twentieth aspect of the present application provides an access backhaul integrated IAB network system, characterized in that the system includes a first IAB node, a second node, a source IAB host, and a target IAB host;

[0097] The target IAB host is used to perform the fourth aspect or any optional method of the fourth aspect;

[0098] The source IAB host is used to perform the fifth aspect or any optional method of the fifth aspect;

[0099] The first IAB node is used to perform the sixth aspect or any optional method of the sixth aspect;

[0100] The second node is used to execute the seventh aspect or any optional method of the seventh aspect.

[0101] The twenty-first aspect of the present application provides a computer-readable storage medium, characterized in that the computer-readable medium stores a computer program for execution by a device, and the computer program includes methods for executing the above-mentioned various aspects or any possible implementation of each aspect.

[0102] The twenty-second aspect of the present application provides a computer program product, including a computer program, which, when executed on a computer device, enables the computer device to execute the methods in the above-mentioned various aspects or any possible implementation of each aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0103] Figure 1 This is a schematic diagram of IAB independent networking;

[0104] Figure 2 This is a schematic diagram of IAB non-independent networking;

[0105] Figure 3 is a schematic diagram of the IAB network user plane protocol stack;

[0106] Figure 4 It is a schematic diagram of the IAB network control plane protocol stack;

[0107] Figure 5 is a schematic diagram of the IAB network system architecture of an embodiment of the present application;

[0108] Figure 6 It is a flowchart of the RLF recovery method of the IAB network in an embodiment of the present application;

[0109] Figure 7 It is a schematic diagram of a scenario of RLF recovery in an embodiment of the present application;

[0110] Figure 8 is another flowchart of the RLF recovery method of the IAB network in an embodiment of the present application;

[0111] Fig. 9 is another flowchart of the RLF recovery method of the IAB network in an embodiment of the present application;

[0112] Fig.10 is another flowchart of the RLF recovery method of the IAB network in an embodiment of the present application;

[0113] Fig.11 is a flowchart of a method for updating PCI in an embodiment of the present application;

[0114] Fig.12 It is a structural diagram of an RLF recovery device of an IAB network in an embodiment of the present application;

[0115] Fig.13 is another structural diagram of the RLF recovery device of the IAB network in an embodiment of the present application;

[0116] Fig.14 is another structural diagram of the RLF recovery device of the IAB network in an embodiment of the present application;

[0117] Fig.15 It is a structural diagram of an RRC reconfiguration device of an IAB network in an embodiment of the present application;

[0118] Fig.16 It is another structural diagram of the RRC reconfiguration device of the IAB network in an embodiment of the present application;

[0119] Fig.17 is a structural diagram of a device for updating PCI in an embodiment of the present application;

[0120] Fig.18 is another structural schematic diagram of a device for updating PCI in an embodiment of the present application;

[0121] Fig.19 is a structural diagram of a communication device in an embodiment of the present application;

[0122] Fig. 20 It is another structural diagram of the communication device in the embodiment of the present application. DETAILED DESCRIPTION

[0123] The embodiments of the present application provide a RLF recovery method, device and related equipment of an IAB network, which are applied to the field of wireless communication technology, and can restore the connection between the second node and the target IAB host as soon as possible, thereby improving the reliability of the network connection. It should be understood that the features or contents marked with dotted lines in the drawings of the embodiments of the present application can be understood as optional operations or optional structures of the embodiments of the present application. In the description of the embodiments of the present application, the words "first", "second" and the like are only used for the purpose of distinguishing the description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order.

[0124] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: global system of mobile communication (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) system or new radio (NR), and future evolved communication systems.

[0125] The user equipment (UE) in the embodiments of the present application is a device with wireless transceiver functions. The UE is also called terminal equipment, mobile station, remote station, etc. The terminal device can be deployed on land, including indoors or outdoors, handheld, wearable or vehicle-mounted; it can also be deployed on the water surface (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons and satellites, etc.). The terminal device can communicate with the core network via the radio access network (RAN) and exchange voice and / or data with the RAN. The terminal device can be a mobile phone, a tablet computer (Pad), a computer with wireless transceiver function, a mobile Internet device (MID), a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, 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 smart home, etc. The embodiments of the present application do not limit the application scenarios. The embodiments of the present application do not limit the specific technology, device form and name adopted by the terminal device.

[0126] The IAB node in the embodiment of the present application may be an access network device, which is a device in the network used to connect a terminal device to a wireless network. The access network device may be a node in a wireless access network, which may also be called a base station, or a radio access network (RAN) node (or device). The network device may include an evolved base station (NodeB or eNB or e-NodeB, evolutionary Node B) in a long term evolution (LTE) system or an evolved LTE system (LTE-Advanced, LTE-A), such as a traditional macro base station eNB and a micro base station eNB in ​​a heterogeneous network scenario, or may also include a next generation node B (next generation node B, gNB) in a fifth generation mobile communication technology (5th generation, 5G) new radio (new radio, NR) system, or may also include a radio network controller (radio network controller, RNC), a node B (Node B, NB), a base station controller (base station controller, BSC), a base transceiver station (base transceiver station, BTS), a transmission reception point (transmission reception point, TRP), a home base station (e.g., home evolved NodeB, or home Node B, HNB), a base band unit (base band unit, BBU), a base band pool BBU pool, or a WiFi access point (access point, AP), etc., or may also include a cloud access network (cloud radio The embodiments of the present application do not limit the centralized unit (CU) and distributed unit (DU) in the CloudRAN access network (CloudRAN) system. In the separate deployment scenario where the access network equipment includes CU and DU, CU supports protocols such as radio resource control (RRC), packet data convergence protocol (PDCP), and service data adaptation protocol (SDAP); DU mainly supports radio link control layer (RLC), media access control layer (MAC) and physical layer protocols.

[0127] Compared with the fourth generation mobile communication system, the fifth generation mobile communication (5G) has put forward more stringent requirements for all network performance indicators. For example, the capacity index has been increased by 1,000 times, with wider coverage requirements, ultra-high reliability and ultra-low latency. On the one hand, considering the rich high-frequency carrier frequency resources, in hot spots, in order to meet the ultra-high capacity requirements of 5G, the use of high-frequency small base stations to form a network is becoming more and more popular. The propagation characteristics of high-frequency carriers are poor, and they are severely attenuated by obstruction and have a narrow coverage range. Therefore, a large number of small base stations need to be deployed densely. Correspondingly, the cost of providing optical fiber backhaul for these densely deployed small base stations is very high, and the construction is difficult. Therefore, an economical and convenient backhaul solution is needed; on the other hand, from the perspective of wide coverage requirements, in some remote areas, network coverage is provided, and the deployment of optical fiber is difficult and costly, so a flexible and convenient access and backhaul solution needs to be designed. The integrated access and backhaul (IAB) technology provides ideas for solving the above two problems: its access link and backhaul link both use wireless transmission solutions to avoid optical fiber deployment.

[0128] In an IAB network, an IAB node (IAB node) or relay node (RN) can provide wireless access services for UEs. The service data of the UE is transmitted by the IAB node to the IAB donor through a wireless backhaul link. In this application, the IAB donor may also be referred to as a donor node or a donor base station (donorgNodeB, DgNB), a donor network device, etc. An IAB node may be composed of a mobile termination (MT) part and a distributed unit (DU) part. When the IAB node faces its parent node, it can act as a terminal device, that is, the role of an MT; when the IAB node faces its child node (the child node may be another IAB node, or an ordinary UE), it is regarded as a network device, that is, the role of a DU. The MT part of the IAB node has some or all of the functions of a UE. 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 IAB host is connected to the core network element (e.g., connected to the 5G core network, 5GC) serving the UE, and provides wireless backhaul functions for the IAB node. For ease of description, the centralized unit of the IAB host is referred to as the donor CU (or simply CU), and the distributed unit of the IAB host is referred to as the donor DU (donor DU). The IAB host may also be in the form of a separation of the control plane (CP) and the user plane (UP), for example, the CU may be composed of a CU-CP and one (or more) CU-UPs.

[0129] In the current 5G standard, considering the small coverage of high-frequency bands, in order to ensure the coverage performance of the network, multi-hop networking may be used in the IAB network. In addition, considering the need for service transmission reliability, the IAB node can support dual connectivity (Dual connectivity, DC) or multi-connectivity to cope with possible abnormalities in the backhaul link, such as link interruption or blockage (blockage) and load fluctuations, and improve the reliability of transmission. Therefore, the IAB network supports multi-hop networking and can also support multi-connection networking. Between the UE served by the IAB node and the IAB host, there is at least one transmission path consisting of multiple links. On a transmission path, there are multiple nodes, such as UE, one or more IAB nodes, and an IAB host (if the IAB host is in the form of CU and DU separated, it also includes an IAB-donor-DU part and an IAB-donor-CU part). Each IAB node regards the adjacent node that provides access and backhaul services to it as a parent IAB node (which can be simply referred to as a parent node). Accordingly, each IAB node can be regarded as a child IAB node of its parent node (which can be simply referred to as a child node). If the data of an IAB node or UE needs to be transmitted through a certain IAB node, then the IAB node or UE is a subordinate node of the certain IAB node. For example, a child node or grandchild node of a certain IAB node is a subordinate node of the certain IAB node. The IAB host can be an access network device. If the IAB host is a CU-DU separated architecture, the IAB host in this application may specifically be the CU of the IAB host (IAB-donor-CU); further, if the CU of the IAB host is a CP-UP separated architecture, the IAB host described in this application may specifically be the CU-CP part of the IAB host (IAB-donor-CU-CP). For the convenience of description, they are all collectively referred to as IAB hosts.

[0130] Furthermore, the UE in the IAB network may also provide network connections for UEs under the UE through a UE-to-Network architecture or through a UE-to-UE architecture.

[0131] In the embodiment of the present application, the relay device or IAB node may also be a UE. In this case, the UE acts as a relay node in the UE-to-Network or UE-to-UE situation. In this case, the IAB host in the embodiment of the present application may be a base station device (for example, a 5G base station device gNB or an LTE base station eNB).

[0132] like Figure 1The schematic diagram of IAB independent networking is shown. In the figure, the parent node of IAB node 1 is the IAB host, and IAB node 1 is the parent node of IAB node 2 and IAB node 3. IAB node 2 and IAB node 3 are both the parent nodes of IAB node 4, and the parent node of IAB node 5 is IAB node 3. The uplink data packet of the UE can be transmitted to the host site IAB host through one or more IAB nodes, and then sent by the IAB host to the mobile gateway device (such as the user plane function unit UPF in the 5G core network). The downlink data packet will be received by the IAB host from the mobile gateway device and then sent to the UE through the IAB node. Figure 1 In the IAB standalone (SA) networking shown, both the IAB node and the UE establish a connection with the network only through the NR standard air interface. It should be understood that Figure 1 The IAB independent networking scenario shown is only exemplary. In the IAB scenario combining multi-hop and multi-connection, there are many other possibilities, such as the IAB host in the figure and the IAB node under another IAB host forming a dual connection to serve the UE, etc., which is not limited in this application.

[0133] The IAB network also supports non-standalone (NSA) networking. Figure 2 A schematic diagram of IAB non-independent networking is shown, in which the IAB node supports dual connectivity of 4G and 5G networks, namely EN-DC (E-UTRAN NR dual connectivity), in which the LTE base station eNB is the master base station (master eNB, MeNB), which provides the IAB node with an LTE air interface (LTE Uu) connection, and establishes an S1 interface with the 4G core network evolved packet core (EPC) for user plane and control plane transmission. The IAB host gNB is a secondary base station, which provides the IAB node with an NR air interface (NR Uu) connection, and establishes an S1 interface with the core network EPC for user plane transmission. Similarly, the UE also supports EN-DC. The UE is connected to the master base station eNB through the LTE Uu interface, and to the secondary base station IAB node through the NR Uu interface. The secondary base station of the UE can also be the IAB host gNB. The IAB non-independent networking scenario in this application can also be referred to as the EN-DC networking scenario of IAB.

[0134] It should be understood that Figure 2 This is just a networking example. The NSA scenario of the IAB network also supports multi-hop IAB networking. For example Figure 2 The UE in may be another IAB node, that is, the IAB node may be connected to the IAB host gNB via a multi-hop wireless backhaul link, which is not limited in this application.

[0135] In the current discussion on the IAB network, it is determined to introduce a new protocol layer in the wireless backhaul link - the backhaul adaptation protocol (BAP) layer. This protocol layer is located above the radio link control (RLC) layer and can be used to implement data packet routing in the wireless backhaul link, as well as bearer mapping and other functions.

[0136] An F1 interface needs to be established between the IAB node (the DU part of the IAB) and the host IAB (or IAB-donor-CU). The interface supports a user plane protocol (F1-U) and a control plane protocol (F1-C), wherein the user plane protocol includes one or more of the following protocol layers: General Packet Radio Service (GPRS) tunneling protocol user plane (GPRS tunneling protocol user plane, GTP-U), user datagram protocol (user datagram protocol, UDP), Internet protocol (internet protocol, IP) and other protocol layers; the control plane protocol of the interface includes one or more of the following: F1 application protocol (F1 application protocol, F1AP), stream control transport protocol (stream control transport protocol, SCTP), IP and other protocol layers.

[0137] like Figure 3 and Figure 4 The schematic diagrams of the IAB network user plane and control plane protocol stacks are shown respectively. Through the control plane of the F1 interface, the IAB node and the IAB host can perform interface management, manage the IAB-DU, and perform UE context-related configuration. Through the user plane of the F1 interface, the IAB node and the IAB host node can perform user plane data transmission, downlink transmission status feedback and other functions.

[0138] See also Figure 5 , Figure 5 : is a schematic diagram of the system architecture of the IAB network in an embodiment of the present application. The system architecture includes an IAB network of an independent network (SA) and an IAB network of a non-independent network (NSA). The system architectures of the two networking scenarios refer to the contents described in the above independent network and non-independent network. According to the previous description, the IAB node includes an MT part and a DU part, the IAB host can be further divided into a DU and a CU part, and the CU can also be divided into a CU-CP and a CU-UP part. Figure 5Further, an example of the architecture in which the IAB node is connected to the IAB host via a wireless backhaul link is given with specific node composition.

[0139] When the IAB node works in SA mode, the IAB host can be connected to the 5G core network (5G core, 5GC), which is the dotted line part in the figure. Among them, the IAB-host-CU-CP is connected to the control plane network element in the 5GC (such as the access and mobility management function AMF) through the NG control plane interface, and the IAB-host-CU-UP is connected to the user plane network element in the 5GC (such as the user plane function UPF) through the NG user plane interface. When the IAB node works in NSA mode (or EN-DC mode), the IAB-host-CU-UP can be connected to the EPC (such as the service gateway (SGW)) through the S1 user plane interface, there is an LTE Uu air interface connection between the MeNB and the MT of the IAB node, there is an X2-C interface between the MeNB and the IAB-host-CU-CP, and the MeNB is connected to the EPC (including the S1 interface user plane and the S1 interface control plane) through the S1 interface. That is the dotted line part in the figure.

[0140] In the embodiment of the present application, the first IAB node may be a parent node, and the second node is a child node or a subordinate UE of the first IAB node, for example Figure 1 The IAB node 1 in the example may be the first IAB node, and the IAB node 2 and the IAB node 3 may be the second nodes. In this case, the second nodes (IAB node 2 and IAB node 3) may communicate with the IAB host through the first IAB node. For example, Figure 1 The IAB node 4 in the example may be a first IAB node, and UE2 and UE1 may be second nodes. In this case, the second nodes (UE2 and UE1) may communicate with the IAB host through the first IAB node. The present application does not limit the number of IAB nodes between the first IAB node and the IAB host.

[0141] In the current IAB network, when an IAB node initially joins the network, the IP address of the DU part of the IAB node can be obtained from the IAB host or OAM. The obtained IP address can be used for subsequent service transmission of the IAB node (specifically, the DU part of the IAB), such as transmitting services of the F1 interface, or transmitting services of non-F1 interfaces. The IP address obtained by the IAB node is related to the IAB-donor-DU to which it is connected, so that the IP address of the IAB node can be reached through IP routing.

[0142] When a radio link failure (RLF) occurs in an IAB node in the IAB network, the IAB node will perform the RLF recovery process, i.e., attempt to re-establish RRC. In another case, the parent node of the IAB node experiences RLF, and after the recovery fails, a BH RLF notification is sent to the IAB node. After receiving the BH RLF notification, the subsequent behavior of the IAB node is similar to the subsequent behavior of the IAB node when RLF occurs, such as performing RLF recovery. During the reconstruction process, the IAB node may choose to re-access the original cell, or it may choose to access a new cell. If the IAB node performs RLF recovery successfully, if it is still connected to the same IAB host CU as before after reconstruction, since the IAB host CU knows the network topology relationship between the IAB node and the subordinate IAB nodes or subordinate UEs (the IAB nodes or UEs connected to the service cell of the IAB node), the previous communication link can be used for data transmission. Alternatively, the IAB node is connected to the same IAB host CU as before through a new parent node, then the IAB host CU can re-establish the connection with the IAB node and its subordinate IAB nodes or subordinate UEs according to the new network topology. Furthermore, if the IAB node is connected to the same IAB host CU as before through a new IAB host DU, the IAB host CU can assign new IP addresses to the IAB node and its subordinate IAB nodes.

[0143] However, for the scenario where the IAB node as a parent node performs RLF recovery and connects to a new IAB host CU, or when the IAB node as a parent node in the IAB network determines to disconnect from the source IAB host CU and connect to the new target IAB host CU. On the one hand, the target IAB host CU does not know the network topology relationship between the IAB node and its child nodes or subordinate UEs; on the other hand, the child nodes or subordinate UEs of the IAB node are not aware of the RLF recovery process of the IAB node as its parent node. The child IAB nodes or subordinate UEs of the IAB node still think that they can connect to the source IAB host via the IAB node, but in fact, they have lost connection with the source IAB host at this time, so the child nodes or subordinate UEs cannot initiate a request to re-establish a connection with the new IAB host, which will eventually cause these child nodes or subordinate UEs to be unable to continue to work normally (neither transmit their own services, nor provide service transmission services for other nodes connected to these child B nodes or subordinate UEs). Therefore, for the child nodes or subordinate UEs of the IAB node, how to quickly restore the connection with the target IAB host and improve the reliability of the network connection is a problem that needs to be solved.

[0144] To this end, the present application provides an RLF recovery method for an IAB network, when a radio link failure RLF occurs in a first IAB node, or the first IAB node receives a first indication message (such as BH RLF indication) sent by a parent node indicating that a radio link failure or radio link recovery failure occurs in the parent node, the first IAB node performs RLF recovery. If the first IAB node establishes an RRC connection with a target IAB host after performing RLF recovery, the first IAB node sends a first message to the second node through SRB1 or SRB2, or the first IAB node sends a second indication message to the second node, wherein the second indication message is used to indicate that a radio link failure occurs in the first IAB node or that an RLF recovery process is performed but the recovery fails (the second indication message may be, for example, BH RLF indication), so that the second node can establish an RRC connection with the target IAB host, and the second node is a child node of the IAB node or a UE connected to a cell served by the IAB node (referred to as a subordinate UE of the IAB node). This avoids the problem that the second node cannot continue to transmit service data and signaling because it does not perceive that the IAB node has changed the host IAB.

[0145] See also Figure 6 , Figure 6 A flowchart of the RLF recovery method of the IAB network in an embodiment of the present application is shown.

[0146] In step 601, the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery.

[0147] When the first IAB node has an RLF, or the first IAB node receives a first indication message (e.g., BH RLF indication) sent by a parent node indicating that a radio link failure or a radio link recovery failure has occurred in the parent node, or the first IAB node is disconnected from the source IAB host, the first IAB node may perform an RLF recovery process. During the RLF recovery process, the first IAB node initiates an RRC connection reestablishment process and establishes an RRC connection with the target IAB host.

[0148] In step 602, the first IAB node sends second indication information to the second node, where the second indication information is used to indicate that a radio link failure occurs in the first IAB node or an RLF recovery process is performed but the recovery fails (the second indication information may be, for example, BH RLF indication), or the first IAB node sends a first message to the second node via SRB1 / SRB2, and the second node is a child node of the IAB node or a UE accessing a cell served by the IAB node (referred to as a subordinate UE of the IAB node).

[0149] Before the first IAB node performs RLF recovery, the second node is connected to the source IAB host through the first IAB node. After the first IAB node performs RRC to reestablish the connection to the target IAB host, the second node does not perceive that the first IAB node has changed the IAB host. To this end, the first IAB node sends a second indication message to the second node, or the first IAB node sends a first message to the second node through SRB1 / SRB2.

[0150] In step 603, the second node establishes an RRC connection with the target IAB host.

[0151] After the second node receives the second indication information (e.g., BH RLF indication) sent by the first IAB node, the second node may initiate an RRC connection re-establishment process to establish an RRC connection with the target IAB host. Alternatively, because the second node receives the first message through SRB1 / SRB2, but the second node fails to perform an integrity check on the first message, the second node may also initiate an RRC connection re-establishment process (e.g., initiate an RRC re-establishment request to the target IAB host) to establish an RRC connection with the target IAB host.

[0152] In an embodiment of the present application, the first IAB node as the parent node can, after being disconnected from the initial source IAB host and connected to the new target IAB host, send a second indication message (e.g., BH RLFindication) to the second node, or send a first message to the second node through SRB1 / SRB2, so that the second node (a child node or a subordinate UE of the first IAB node) can trigger the RRC connection re-establishment process, thereby avoiding the problem that the second node is unable to continue the service data and signaling transmission due to the fact that the first IAB node does not perceive that the IAB host has been replaced, so that the connection between the second node and the target IAB host can be restored as soon as possible, thereby improving the reliability of the network connection.

[0153] According to the foregoing description, the embodiments of the present application can be used in an IAB network with variable scenarios (the number of IAB nodes between the first IAB node and the source IAB host and the target IAB host is uncertain, the number of subordinate nodes of the first IAB node is also uncertain, etc.). Therefore, as long as the IAB network includes a second node, a first IAB node, a source IAB host, and a target IAB host, the RLF recovery method of the IAB network provided by the embodiments of the present application can be used, so that after the first IAB node replaces the IAB host, the connection between the second node and the target IAB host is restored as soon as possible, thereby improving the reliability of the network connection. The RLF recovery method of the IAB network provided by the present application will be described below in conjunction with a specific scenario. It should be determined that the scenario is only for the convenience of understanding the technical solution provided by the embodiments of the present application, and should not be used as a condition to limit the present application.

[0154] See also Figure 7 , Figure 7 Schematic diagram of the scenario of RLF recovery in the embodiment of the present application. Figure 7 As shown, the node where the radio link fails and attempts to recover is the IAB node 3, which can provide access and backhaul services for one or more UEs / sub-nodes. Figure 7 In the figure, UE1 accessing the cell served by IAB node 3 and child node IAB node 4 are shown. There is also a UE2 under IAB node 4, and UE2 accesses the cell served by IAB node 4. In the actual network deployment scenario, IAB node 3 may have one or more grandchild nodes (IAB nodes connected to IAB node 3 through at least two hops of wireless backhaul links), and IAB node 4 may serve more UEs, or child nodes or grandchild nodes, which are not shown one by one in the figure, but it should be understood that these possible scenarios are not included. Figure 7 is limited by the examples.

[0155] For ease of description, these IAB nodes or UEs connected to the IAB host via the IAB node 3 are referred to as descendant IAB nodes or subordinate UEs of the IAB node 3. The source IAB host in the embodiment of the present application may also be referred to as the initial IAB host, or the old IAB host, the target IAB host may also be referred to as the new IAB host, the IAB node 3 may also be referred to as the first IAB node, and the UE 1 or the IAB child node 4 may also be referred to as the second node.

[0156] In an embodiment of the present application, RLF recovery can be centrally managed by the target IAB host (the target IAB host sends a second message to the subordinate nodes of the target IAB host, and the second message carries an RRC message), or RLF recovery can be performed through distributed management (the subordinate nodes of the target IAB host perform RLF recovery according to the prompt information of the target IAB host). The subordinate nodes of the target IAB host refer to nodes connected to the IAB host through a one-hop or multi-hop wireless link (the node can specifically be an IAB node or a UE). A node connected to the IAB host through a one-hop wireless link refers to a node that directly accesses the IAB host; a node connected to the IAB host through a multi-hop wireless link refers to a node that is connected to the IAB host via at least one intermediate IAB node. For example, in Figure 7 In the example, IAB node 1, IAB node 3, IAB node 4, UE1 and UE2 are all subordinate nodes of the target IAB host. They are described below. Figure 8 As shown, Figure 8 FIG. 1 is another flow chart of the RLF recovery method of the IAB network in the embodiment of the present application. Figure 8 In the flowchart of FIG. 1 , RLF recovery is centrally managed by the target IAB host.

[0157] In step 801, the IAB node 3 sends an RRC re-establishment request to the target IAB host.

[0158] IAB node 3 detects that it and the old parent node (i.e. Figure 7 When a wireless link failure occurs between the wireless link between the IAB node 2 and the wireless link between the parent node and the IAB node 2 shown in FIG, the wireless link between the parent node and the IAB node 2 is selected to access the new parent node (i.e. Figure 7 The cell served by the IAB node 1 shown in the figure is served, and an RRC connection re-establishment process is performed with the target IAB host (specifically, it can also be a target IAB-donor-CU, or a target IAB-donor-CU-CP) via the IAB node 1. During the RRC connection re-establishment process, the IAB node 3 first sends an RRC re-establishment request to the target IAB host.

[0159] Or optionally, the IAB node 3 may autonomously choose to disconnect from the source IAB host and connect to the target IAB host. For example, the IAB node 3 may determine based on the result of performing the measurement: the signal quality of the currently connected cell (the cell served by the IAB node 2) is less than the preset threshold value T1 and the signal quality of other surrounding cells (the cell served by the IAB node 1) is higher than the preset threshold value T2, or the signal quality of the cell currently connected by the IAB node 3 (the cell served by the IAB node 2) is worse than the signal quality of other surrounding cells (the cell served by the IAB node 1) and the difference is greater than or equal to the preset threshold value T3, the IAB node 3 may disconnect from the currently connected cell and connect to the new cell (i.e., the cell served by the IAB node 1). The signal quality of the cell may be, for example, the RSRP of the cell, or the RSRQ of the cell, or the measured SINR.

[0160] Alternatively, the IAB node 3 may be configured with conditional handover, for example, when connected to the source IAB host, the IAB node 3 pre-acquires configuration information related to the conditional handover, including necessary configuration required to establish a connection with the target IAB host (for example, configuration information generated by the target IAB host for the IAB node 3 to switch to the target IAB host), and the IAB node 3 is also configured with preset conditions for triggering the conditional handover. When the preset conditions are met, the IAB node 3 performs the handover process based on the pre-acquired necessary configuration required to establish a connection with the target IAB host, and establishes a connection with the target IAB host. Among them, the preset conditions may be: the signal quality of the currently connected cell is less than the preset threshold value T1 and the signal quality of the candidate cell is higher than the preset threshold value T2, or the signal quality of the cell to which the IAB node 3 is currently connected is worse than the signal quality of the candidate cell and the difference is greater than or equal to the preset threshold value T3; or, when the RLF or switching fails, the IAB node 3 selects a new cell served by a parent node connected to the target IAB host for access, and this new cell happens to be one of the candidate cells included in the configuration information related to the conditional switching obtained in advance. In this case, the IAB node 3 attempts to perform conditional switching to connect to the target IAB host. For more preset conditions related to conditional switching, please refer to the prior art and will not be repeated here.

[0161] Alternatively, as another possible embodiment, when a handover failure or a conditional handover failure occurs in the IAB node 3, an RRC re-establishment process is to be performed, and the selected new access cell is a cell served by a parent node connected to the target IAB host. After the IAB node 3 performs the RRC re-establishment process, it is connected to the target IAB host through the parent node.

[0162] The embodiment of the present application does not limit the implementation scenario in which the IAB node 3 can autonomously choose to disconnect from the source IAB host and connect to the target IAB host. After the IAB node determines to connect to the target IAB host, it initiates an RRC re-establishment request to the target IAB host. For the specific process, refer to the following IAB node performing RLF recovery process. For IAB node 3, during the process of performing RLF recovery, if the cell access served by the new parent node (IAB node 1) is selected, the newly accessed cell identifier can be used to determine whether the newly accessed parent node is connected to the new target IAB host. Specifically, it can be judged according to the cell identifier part contained in the system information of the accessed cell. This is because the cell identifier (for example, the NR cell identifier (NRcell identifier, NCI) of the cell) contains the identifier of the base station gNB, and the gNB identifiers corresponding to different IAB host network devices are different. Therefore, after obtaining the system information of the cell to be accessed, the IAB node 3 can determine whether it is connected to the new IAB host after RLF recovery according to the gNB identifier in the accessed cell identifier carried in the system information. The system information can also be called the first message. Accordingly, after determining the cell connected to the target IAB host, the IAB node 3 can send an RRC re-establishment request to the new IAB host (i.e., the target IAB host, specifically, the target IAB-donor-CU, or the target IAB-donor-CU-CP) via the new parent node (i.e., the IAB node 1) to request to establish an RRC connection with the target IAB host. Optionally, the IAB node 3 can also send an RRC message carrying information for requesting an IP address to the new IAB host (i.e., the target IAB host, specifically, the target IAB-donor-CU, or the target IAB-donor-CU-CP), which can specifically include the number and type information of IP addresses for different purposes (the type can be, for example, an IPv4 address, an IPv6 address, an IPv6 address prefix), and the purpose of the IP address can be any of the following: for the transmission of an F1 interface control plane message (i.e., an F1-C service), or for the transmission of an F1 interface user plane message (i.e., an F1-U service), or for the transmission of a non-F1 interface message (i.e., a non-F1 service), or for all services.

[0163] It should be understood that the node where the wireless link failure occurs in the embodiment of the present application is the IAB node. In actual applications, the node where the wireless link failure occurs may also be the UE. The UE can act as a relay node to provide connection services to the network for other UEs (which can be regarded as subordinate UEs).

[0164] It should be understood that in the application scenario described in the embodiment of the present application, the IAB node 3 performing the recovery is connected to the IAB host through the parent node 1 or 2, and in the actual application scenario, the IAB node 3 performing the recovery may not be connected through the parent node, but directly connected to the cell served by the host node (specifically, it may be an IAB host DU, i.e., IAB-donor-DU, or an IAB host with complete functions and not CU-DU separated deployment), and the present application does not limit this. Figure 8 In the flowchart, if combined with Figure 7 Schematic diagram of the scenario, IAB node 3 needs to send an RRC re-establishment request to the target IAB host through IAB node 1. For simplicity of description, Figure 8 The flowchart and related description ignore IAB node 1.

[0165] In step 802, the target IAB host sends a context acquisition request to the source IAB host.

[0166] After the target IAB host receives the RRC re-establishment request sent by the first IAB node, the target IAB host sends a context acquisition request to the source IAB host to acquire context information of the IAB node 3 .

[0167] In step 803, the source IAB host sends a context acquisition response to the target IAB host.

[0168] In addition to sending the context information of the MT part of the IAB node 3 (including the identifier of the IAB node 4) to the target IAB host through the Xn interface, the source IAB host may also carry the information of the subordinate IAB node / subordinate UE originally served by the IAB node 3 in the context acquisition response, and the information may specifically include one or more of the following contents: the identifier of the subordinate IAB node / subordinate UE (for example, the identifier of the IAB node 4, and / or the identifier of UE1, etc.), the identifier of the child node of each subordinate IAB node, the identifier of the parent node of each subordinate IAB node, the identifier of the cell served by the parent node to which each subordinate IAB node / subordinate UE accesses, and the identifier of the cell served by the parent node may specifically be, for example, the physical cell identifier PCI of the cell, or the NR cell identifier (NR Cell ID, NCI) of the cell, or the global cell identifier (NR CellGlobally Identifier, NCGI), etc. Among them, the identifier of the subordinate IAB node / subordinate UE can be the F1AP UE ID assigned to the subordinate IAB node / subordinate UE on the F1 interface between the IAB node 3 and the source IAB host (such as the gNB-CU F1AP UE ID assigned by the IAB host, or the gNB-DU F1AP UE ID assigned by the parent node (such as the IAB node 3) to which the subordinate IAB node / subordinate UE accesses), or it can be, for example, the Cell Radio Network Temporary Identifier (C-RNTI) of the subordinate IAB node / subordinate UE in the accessed cell. Based on the identification information of these subordinate IAB nodes / subordinate UEs, the target IAB host can know which IAB nodes and UEs under the IAB node 3 need to trigger RRC re-establishment. Optionally, the source IAB host can also send the topological connection relationship between the IAB node 3 and these subordinate IAB nodes and subordinate UEs to the target IAB host. In this way, when the target IAB host sends a second message for triggering RRC re-establishment to the subordinate IAB node / subordinate UE in a subsequent step, the second message can be any RRC message, and it can be determined that after the RRC connection of a certain IAB node is successful and the F1 connection is available, the second message for triggering RRC re-establishment can be sent to the child node or subordinate UE of the IAB node.

[0169] Optionally, for a certain IAB node (e.g., IAB node 3, or IAB node 4, or other subordinate IAB nodes of IAB node 3, etc.), in the process of executing the context acquisition process of the IAB node between the source IAB host and the target IAB host, the context information of the DU part of the IAB node also needs to be considered. For example, when the source IAB host sends a context acquisition response containing the context information of the MT part of the IAB node to the target IAB host, the context acquisition response may also contain the context information of the DU part of the IAB node, specifically including, for example: the gNB DU ID of the IAB node DU, the name of the DU, the configuration information of the cell served by the DU part, the configuration information of the F1 interface between the DU and the source IAB donor, the user plane tunnel information carried on the F1 interface, the context information of the UE served by all DUs of the F1 interface, etc. Alternatively, in another possible manner, the message containing the context information of the MT part of the IAB node sent by the source IAB host to the target IAB host may also be a different message from the message containing the context information of the DU part of the IAB node. For example, the target IAB host may obtain the context information of the DU part of the IAB node from the source IAB host before establishing the F1 connection with the IAB node.

[0170] In step 804, the target IAB host sends an RRC re-establishment message to the IAB node 3, for instructing the IAB node 3 to perform RRC re-establishment.

[0171] In step 805, the IAB node 3 sends an RRC re-establishment completion message to the target IAB host, indicating that the corresponding configuration has been successfully completed according to the configuration provided by the target IAB host in the RRC re-establishment message.

[0172] In step 806, an F1 connection is established between the IAB node 3 and the target IAB host, which may specifically be an F1 setup process or an F1 connection re-establishment process.

[0173] In step 807 , the target IAB host sends a second message to the IAB node 3 .

[0174] After the RRC connection between the target IAB host (specifically, the MT part of the IAB node 3) and the IAB node 3 is successful, and the F1 interface between the target IAB host and the DU part of the IAB node 3 is available, the target IAB host sends a second message to the IAB node 3. The second message includes the identifier of the IAB node 4, the RRC message and the SRB identifier. The SRB identifier includes the identifier of SRB1 or SRB2.

[0175] In step 808, the IAB node 3 sends a first message to the IAB node 4 through SRB1 or SRB2.

[0176] After the IAB node 3 receives the second message sent by the target IAB host, the IAB node 3 sends a first message to the IAB node 4 according to the identifier of the IAB node 4. The first message is the RRC message in the second message.

[0177] In order for the control plane to convey control instructions, a transmission channel must be established. The signaling channel established through the wireless link between the second node and the IAB node 3 is called the signaling radio bearer (SRB for short). Specifically, in the wireless interface protocol stack between the second node and the IAB node 3, layer three of the wireless interface protocol stack is the RRC (Radio Resource Control) layer, and SRB transmits layer three signaling on it. Specifically, the signaling radio bearer may include SRB0, SRB1, and SRB2. SRB0 is generally used to transmit RRC messages on the logical channel common control channel (CCCH), and is generally used for transmission signaling for UE initial access. SRB1 is generally used to transmit RRC messages on dedicated channels. SRB2 is generally used to transmit non-access stratum (NAS) messages on the dedicated control channel (DCCH), has a lower priority than SRB1, and SRB2 is always configured after the security mode is activated. NAS messages transmitted via SRB2 are included in RRC messages, but these NAS messages do not include any RRC protocol control information. They are only included in RRC messages when they are transmitted, which means that RRC messages are just a carrier. Once the security mode is activated, all RRC messages (including some NAS or 3GPP messages) transmitted via SRB1 and SRB2 will be integrity protected and encrypted via the Packet Data Convergence Protocol (PDCP).

[0178] In step 809, the IAB node 4 performs an integrity check on the first message. If the check fails, RRC re-establishment is triggered.

[0179] According to the description in step 808, the first message transmitted through SRB1 and SRB2 will be processed by integrity protection and / or encryption of the target IAB host. Before the IAB node 3 establishes a connection with the target IAB host by executing the RLF recovery process, the IAB host to which the IAB node 4 connects through the IAB node 3 is the source IAB host. Therefore, before the IAB node 4 (i.e., the child node of the IAB node 3, or the subordinate UE) establishes an RRC connection with the target IAB host, the security protection scheme (encryption, integrity protection, etc.) of the IAB node 4 is still the security mechanism negotiated with the source IAB host (including, for example, encryption keys, encryption algorithms, integrity protection keys, integrity protection algorithms, etc.). Therefore, after the target IAB host establishes a connection with the IAB node 3, since the IAB node 4 does not perceive the replacement of the IAB host, the IAB node 4 still uses the original method (i.e., the security algorithm and key configured by the source IAB host, specifically including the integrity protection algorithm and key configured by the source IAB host, etc.) to perform integrity protection check on the first message, resulting in the failure of the integrity check of the first message, triggering the RRC re-establishment process.

[0180] In step 810, the IAB node 4 performs an RRC re-establishment process with the target IAB host.

[0181] The specific description of step 810 can refer to the aforementioned RRC re-establishment process between the IAB node 3 and the target IAB host, specifically the relevant contents of steps 801 to 805, and the IAB node 3 therein is replaced with the IAB node 4 for understanding. It should be noted that if in step 803, the target IAB host obtains the context information of the IAB node 4, the target IAB host does not need to send a context acquisition request for the IAB node 4 to the source IAB host again.

[0182] In step 811, an F1 connection is established between the IAB node 4 and the target IAB host, specifically by executing an F1 setup process or an F1 connection re-establishment process.

[0183] After the RRC re-establishment is successfully performed between the IAB node 4 and the target IAB host (for example, the IAB node 4 successfully sends an RRC re-establishment completion message to the target IAB host through the IAB node 3), the IAB node 4 may also establish an F1 connection with the target IAB host (specifically, it may be to initiate an F1 connection establishment process, or an F1 connection re-establishment process). It is worth noting that in the embodiment of the present application, the F1 connection establishment or re-establishment process between the IAB node and the target IAB host may also include the following processes (although not shown in the figure): the SCTP association (SCTP Association, or Transport Network Layer association, TNL association) establishment process between the two nodes, the security negotiation process related to the Internet Protocol Security (IPsec) of the F1 interface, etc.

[0184] In step 812, the target IAB host sends a second message to UE2.

[0185] After the RRC connection between the target IAB host and the IAB node 4 (specifically, the MT part of the IAB node 4) is successful and the F1 interface between the target IAB host and the DU part of the IAB node 4 is available, the target IAB host sends a second message to the IAB node 4. The second message includes the identifier of UE2, the RRC message and the SRB identifier. The SRB identifier includes the identifier of SRB1 or SRB2.

[0186] In step 813, IAB node 4 sends a first message to UE2 through SRB1 or SRB2.

[0187] After the IAB node 4 receives the second message sent by the target IAB host, the IAB node 4 sends a first message to the UE 2 according to the identifier of the UE 2. The first message is the RRC message in the second message.

[0188] In step 814, UE2 performs an integrity check on the first message. If the check fails, RRC re-establishment is triggered.

[0189] In step 815, an RRC re-establishment procedure is performed between UE2 and the target IAB host.

[0190] The description of steps 812 to 815 may be understood by referring to the description of steps 807 to 810. It should be noted that if the target IAB host obtains the context information of UE2 in step 803, the target IAB host may not need to send a context acquisition request for UE2 to the source IAB host again.

[0191] In the above technical solution, the target IAB host is required to obtain the identifier of the child node or subordinate UE of the first IAB node (i.e., the identifier of the second node) when obtaining the context information of the first IAB node that performs RRC re-establishment, and then after the RRC connection between the first IAB node and the target IAB host is successfully established and the F1 connection is available, any RRC message carried on SRB1 or SRB2 is sent to the second node via the first IAB node, thereby triggering the second node to perform the RRC connection re-establishment process, so that an RRC connection is established between the second node and the target IAB host.

[0192] By adopting the above-mentioned technical solution of the present application, after RLF occurs in the IAB node, if the RLF recovery is performed and the node is connected to the new IAB host, the second node served by the IAB node can also trigger RRC re-establishment. This can avoid the second node being unable to continue service data or signaling transmission because it does not perceive the change of the IAB host. When using this solution, the second node can be a UE or an IAB node. This can be compatible with some scenarios where the UE cannot perform RRC re-establishment based on the signaling of the IAB node.

[0193] The above describes the scenario where RLF recovery is centrally managed by the target IAB host. The following describes the scenario where RLF recovery is performed through distributed management. Fig. 9 , Fig. 9 Another flowchart of the RLF recovery method of the IAB network in the embodiment of the present application is shown.

[0194] In step 901, the IAB node 3 sends an RRC re-establishment request to the target IAB host.

[0195] In step 902, the target IAB host sends a context acquisition request (eg, a RETRIEVE UECONTEXT REQUEST message) to the source IAB host.

[0196] In step 903, the source IAB host sends a context acquisition response (eg, a RETRIEVE UECONTEXT RESPONSE message) to the target IAB host.

[0197] In one possible manner, in step 903, in addition to sending the context information of the MT part of the IAB node 3 (including the identifier of the IAB node 4) to the target IAB host through the Xn interface, the source IAB host may also carry the information of the subordinate IAB node / subordinate UE originally served by the IAB node 3 in the context acquisition response, and the information may specifically include one or more of the following contents: the identifier of the subordinate IAB node / subordinate UE, the identifier of the child node of each subordinate IAB node, the identifier of the parent node of each subordinate IAB node, the identifier of the cell served by the parent node to which each subordinate IAB node / subordinate UE accesses (for example, the PCI of the cell, the NCI of the cell, or the NCGI), etc. Among them, the identifier of the subordinate IAB node / subordinate UE can be the F1APUE ID assigned to the subordinate IAB node / subordinate UE on the F1 interface between the IAB node 3 and the source IAB host (such as the gNB-CU F1AP UE ID assigned by the IAB host, or the gNB-DU F1AP UE ID assigned by the parent node (such as IAB node 3) to which the subordinate IAB node / subordinate UE accesses), or it can be, for example, the C-RNTI of the subordinate IAB node / subordinate UE in the accessed cell. Based on the identification information of these subordinate IAB nodes / subordinate UEs, the target IAB host can know which IAB nodes and UEs under the IAB node 3 need to trigger RRC re-establishment. Optionally, the source IAB host can also send the topological connection relationship between the IAB node 3 and these subordinate IAB nodes and subordinate UEs to the target IAB host. In this way, when the target IAB host sends a second message for triggering RRC re-establishment to the subordinate IAB node / subordinate UE in a subsequent step, the second message can be any RRC message, and it can be determined that after the RRC connection of a certain IAB node is successful and the F1 connection is available, the second message for triggering RRC re-establishment can be sent to the child node or UE of the IAB node.

[0198] For a certain IAB node (e.g., IAB node 3, or IAB node 4, or other subordinate IAB nodes of IAB node 3, etc.), in the process of executing the context flow of obtaining the IAB node between the source IAB host and the target IAB host, the context information of the DU part of the IAB node also needs to be considered. Optionally, for example, when the source IAB host sends a message containing the context information of the MT part of the IAB node to the target IAB host, the context information of the DU part of the IAB node may also be included in the message, specifically including, for example: the gNB DU ID of the IAB node DU, the name of the DU, the configuration information of the cell served by the DU part, the configuration information of the F1 interface between the DU and the source IAB donor, the user plane tunnel information carried on the F1 interface, the context information of the UE served by all DUs of the F1 interface, etc. Alternatively, in another possible manner, the message containing the context information of the MT part of the IAB node sent by the source IAB host to the target IAB host may also be a different message from the message containing the context information of the DU part of the IAB node. For example, the target IAB host may obtain the context information of the DU part of the IAB node from the source IAB host before establishing the F1 connection with the IAB node.

[0199] In step 904 , the target IAB host sends an RRC reestablishment (RRCReestablishment) message or an RRC setup (RRCSetup) message to the IAB node 3 .

[0200] The RRC re-establishment message is also referred to as a second message, and the RRC re-establishment message may include first indication information. The first indication information is used to indicate that the RRC re-establishment performed by the first IAB node is an RRC re-establishment across IAB hosts.

[0201] In step 905, the IAB node 3 sends an RRC reestablishment complete (RRCReestablishmentComplete) message or an RRC setup complete (RRCSetupComplete) message to the target IAB host.

[0202] In step 906, an F1 connection is established between the IAB node 3 and the target IAB host, which may be performed by executing an F1 setup process or by executing an F1 connection re-establishment process.

[0203] In step 907, IAB node 3 sends second indication information to IAB node 4, where the second indication information is used to indicate that a radio link failure occurs in the first IAB node or an RLF recovery process is performed but the recovery fails (the second indication information may be, for example, BH RLF indication), or a first message is sent to IAB node 4 through SRB1 or SRB2.

[0204] According to the first indication information in the RRC re-establishment message, the IAB node 3 perceives that the RRC re-establishment performed by itself is an RRC re-establishment across the IAB host. The IAB node 3 can therefore know that its own child nodes or subordinate UEs also need to perform RRC re-establishment. Therefore, the IAB node 3 sends a BH RLF indication to the IAB node 4, or sends a first message to the IAB node 4 through SRB1 or SRB2 (specifically, the first message is sent to the MT of the IAB node 4 through SRB1 or SRB2 of the MT part of the IAB node 4). The first message can specifically be any RRC message generated by the IAB node 3, or any data packet generated by the IAB node 3.

[0205] In step 908, the IAB node 4 performs an integrity check on the first message, and triggers RRC re-establishment if the check fails, or triggers RRC re-establishment according to the received second indication information (eg, BH RLF indication).

[0206] Before the IAB node 3 establishes a connection with the target IAB host by executing the RLF recovery process, the IAB host to which the IAB node 4 is connected through the IAB node 3 is the source IAB host. Therefore, before the IAB node 4 establishes an RRC connection with the target IAB host, the security protection scheme (encryption, integrity protection, etc.) of the IAB node 4 is still the security mechanism negotiated with the source IAB host (including, for example, encryption keys, encryption algorithms, integrity protection keys, integrity protection algorithms, etc.). Therefore, after the target IAB host establishes a connection with the IAB node 3, since the IAB node 4 does not perceive the replacement of the IAB host, the IAB node 4 still uses the original method (i.e., the security algorithm and key configured by the source IAB host, specifically including the integrity protection algorithm and key configured by the source IAB host, etc.) to perform integrity protection verification on the first message, resulting in a failure in the integrity verification of the first message, triggering the RRC re-establishment process.

[0207] In step 909, the IAB node 4 performs an RRC re-establishment process with the target IAB host.

[0208] For a specific description, reference may be made to the aforementioned RRC re-establishment process between the IAB node 3 and the target IAB host, specifically the relevant contents of steps 901 to 905. It should be noted that if in step 903, the target IAB host obtains the context information of the IAB node 4, the target IAB host may not need to send a context acquisition request message for the IAB node 4 to the source IAB host again.

[0209] In step 910, an F1 connection is established between the IAB node 4 and the target IAB host, specifically by executing an F1 setup process or an F1 connection re-establishment process.

[0210] In step 911, IAB node 4 sends a first message to UE 2 through SRB1 or SRB2.

[0211] After IAB node 4 receives the second message sent by the target IAB host, IAB node 4 sends a first message to UE 2. The first message may be any RRC message generated by IAB node 4 or any data packet generated by IAB node 4, and the first message may be different from the first message in step 907.

[0212] In step 912, UE2 performs an integrity check on the first message. If the check fails, RRC re-establishment is triggered.

[0213] In step 913, an RRC re-establishment process is performed between UE2 and the target IAB host.

[0214] For the relevant description of steps 911 to 913 , reference may be made to the relevant description of steps 907 to 909 mentioned above.

[0215] About Fig. 9 For a description of some of the steps, please refer to the above Figure 8 For example, step 901 can be understood by referring to the description of step 801, and step 908 can be understood by referring to the description of step 809, etc.

[0216] In the embodiment of the present application, after the first IAB node is connected to the new IAB host, the first IAB node perceives that the RRC reestablishment performed by the first IAB node is an RRC reestablishment across IAB hosts through the first indication information of the target IAB host, and sends the second indication information to the second node or sends the first message to the second node through SRB1 or SRB2, triggering the RRC reestablishment process of the second node, so that the second node can establish an RRC connection with the target IAB host.

[0217] use Fig. 9 The described solution can be implemented and Figure 8The same technical effect. In addition, by carrying the first indication information in the RRC re-establishment message, the signaling transmission between the target IAB host and the first IAB node can be reduced, reducing the consumption of network transmission resources. And after reducing the signaling transmission, the RRC re-establishment process of the second node can be triggered more quickly, reducing the impact of RLF and improving the user experience.

[0218] In the above Figure 8 and Fig. 9 In the technical solution, the second node needs to perform the RRC re-establishment process. The RRC re-establishment process will increase the time the second node is disconnected from the network, and from the perspective of the second node, the RRC re-establishment is performed after the connection between the second node and the network is abnormal, so the experience is poor. This application provides another RLF recovery method for an IAB network. By using this method, the time for RRC re-establishment can be reduced, thereby reducing the impact of RLF on UE or IAB nodes and improving user experience. Please refer to Fig.10 , Fig.10 Another flowchart of the RLF recovery method of the IAB network in the embodiment of the present application is shown.

[0219] In step 1001, the IAB node 3 sends an RRC re-establishment request to the target IAB host.

[0220] In step 1002, the target IAB host sends a context acquisition request to the source IAB host.

[0221] In step 1003, the source IAB host sends a context acquisition response to the target IAB host.

[0222] In step 1004 , the target IAB host sends an RRC re-establishment message to the IAB node 3 .

[0223] The RRC re-establishment message is also referred to as a second message, and the RRC re-establishment message includes indication information. The indication information is used to indicate that the RRC re-establishment performed by the first IAB node is an RRC re-establishment across IAB hosts.

[0224] In step 1005, the IAB node 3 sends an RRC re-establishment completion message to the target IAB host.

[0225] In step 1006, an F1 connection is established between the IAB node 3 and the target IAB host, which may specifically be an F1 setup process or an F1 connection re-establishment process.

[0226] The details of steps 1001 to 1006 may be understood by referring to the description of the aforementioned steps 801 to 806.

[0227] In step 1007 , the target IAB host generates a first RRC reconfiguration message to be sent to the IAB node 4 .

[0228] In step 1008, the target IAB host sends a first RRC reconfiguration message to the source IAB host.

[0229] In step 1009, the source IAB host performs PDCP layer transmission side processing on the first RRC reconfiguration message, and the processing may include any one or more of the following: encryption, integrity protection, adding PDCP header information, performing header compression, etc.

[0230] The PDCP layer is a sub-protocol layer of the radio interface protocol stack, which processes radio resource management (RRC) messages on the control plane and upper-layer data packets (such as Internet Protocol (IP) packets) on the user plane. On the user plane, after the PDCP sublayer receives the IP data packet from the upper layer, it can perform header compression and encryption on the IP data packet and then deliver it to the RLC sublayer. The PDCP sublayer also provides in-order submission and duplicate packet detection functions to the upper layer. On the control plane, the PDCP sublayer provides signaling transmission services for the upper layer RRC, and implements encryption and integrity protection of RRC signaling on the sending side, as well as decryption and integrity verification of RRC signaling in the reverse direction (receiving side). Before the first IAB node (e.g., IAB node 3) establishes a connection with the target IAB host by executing the RLF recovery process, the IAB host to which the second node is connected through the first IAB node is the source IAB host. Therefore, before the second node (i.e., the child node of the first IAB node, or the subordinate UE, e.g., IAB node 4) establishes an RRC connection with the target IAB host, the security protection scheme (encryption, integrity protection, etc.) of the second node is still the security mechanism negotiated with the source IAB host (including, for example, encryption key, encryption algorithm, integrity protection key, integrity protection algorithm, etc.). Therefore, if the target IAB host directly sends the first RRC reconfiguration message to the second node after establishing a connection with the first IAB node, and the target IAB host encrypts and integrity protects the first RRC reconfiguration message itself, the second node may not pass the integrity protection check of the first RRC reconfiguration message, and cannot correctly decrypt the first RRC reconfiguration message. Therefore, after the target IAB host generates the first RRC reconfiguration message, it can first be sent to the source IAB host through the Xn interface, and carry the identifier of the second node (for example, IAB node 4) on the Xn interface. The source IAB host then performs PDCP layer encryption and integrity protection on the first RRC reconfiguration message according to the encryption method (including encryption algorithm, and secret key) and integrity protection method (including integrity protection algorithm, and secret key) used for communication with the second node, and then transmits the PDU of the PDCP encapsulating the first RRC reconfiguration message back to the target IAB host. The PDU is also called the third message.

[0231] In step 1010, the source IAB host sends a third message to the target IAB host.

[0232] In step 1011 , the target IAB host sends a third message to the IAB node 4 .

[0233] Specifically, the target IAB host may send a third message to the IAB node 4 via the IAB node 3. The third message includes the first RRC reconfiguration message, and the first RRC reconfiguration message may include a handover command sent to the IAB node 4. Specifically, the third message may include a synchronous reconfiguration (Reconfiguration with Sync) IE (which may be regarded as a handover command), and may also include content related to the PDCP layer security configuration of the SRB / DRB of the target IAB host and the second node. Based on the third message, the second node (IAB node 4) may perform a handover process, and then adopt an updated configuration corresponding to the target IAB host.

[0234] The third message may be included by the target IAB host in an F1AP message sent to the IAB node 3. The F1AP message may be a UE-associated F1AP message, which may include an identifier for identifying the IAB node 4 on the F1 interface between the IAB node 3 and the target IAB host, such as the gNB-DU F1AP UEID assigned by the IAB node 3 to the IAB node 4, the gNB-CU F1AP UE ID assigned by the target IAB host to the IAB node 4, etc.

[0235] Then, the IAB node 3 sends a third message encapsulating the first RRC reconfiguration message to the IAB node 4 .

[0236] In step 1012, the IAB node 4 performs a random access process in the designated target cell according to the information related to the handover command included in the first RRC reconfiguration message.

[0237] In one possible manner, the target IAB host sends a first RRC reconfiguration message to the IAB node 4, which also includes a random access-free indication (for example, the random access-free indication is included in the synchronization reconfiguration IE, or the random access-free indication is included in the first RRC reconfiguration message by an independent IE but not included in the synchronization reconfiguration IE), and the IAB node 4 may not need to perform the random access process in step 1012. On the contrary, if the first RRC reconfiguration message includes the synchronization reconfiguration IE but does not include the random access-free indication, the IAB node 4 may perform step 1012 and re-perform random access in the target cell (for example, the cell served by the DU part of the IAB node 3 after it is connected to the target IAB host).

[0238] In step 1013, the IAB node 4 sends an RRC reconfiguration completion message to the target IAB host.

[0239] Specifically, the IAB node 4 can send an RRC reconfiguration completion message to the target IAB host via the IAB node 3. The RRC reconfiguration completion message can be encapsulated by the IAB node 3 in an F1AP message and sent to the target IAB host. The F1AP message may include an identifier for identifying the IAB node 4 on the F1 interface between the IAB node 3 and the target IAB host, such as the gNB-DU F1AP UE ID assigned by the IAB node 3 to the IAB node 4, the gNB-CU F1APUE ID assigned by the target IAB host to the IAB node 4, etc.

[0240] In step 1014, an F1 connection is established between the IAB node 4 and the target IAB host, which may specifically be an F1 setup process or an F1 connection re-establishment process.

[0241] In step 1015, UE2 performs RRC reconfiguration with the target IAB host.

[0242] For UE2 served by IAB node 4, the target IAB host can also generate an RRC reconfiguration message for UE2, which is used for UE2 to perform switching and update the configuration content of UE2. The specific process can be understood by referring to steps 1007 to 1013 of IAB node 4. It should be noted that for traditional old version UEs, the RRC reconfiguration message sent by the target IAB host to the UE does not need to carry an indication of free random access. In this case, the UE can perform a random access process similar to step 1012 in the target cell specified by the switching command carried in the received RRC reconfiguration message (for example, the cell served by the DU part of IAB 4 after it is connected to the target IAB host).

[0243] About Fig.10 For a description of some of the steps, please refer to the above Figure 8 For example, step 1001 can refer to the description of step 801, and step 1014 can refer to the description of step 811, etc.

[0244] In the embodiment of the present application, after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the target IAB host can reduce the time for the second node to restore the RRC connection with the target IAB host by sending a third message to the second node, avoiding the second node also thinking that the connection with the network is abnormal, thereby reducing the impact of the RLF of the first IAB node on the subordinate nodes and improving the user experience. And the solution of the embodiment of the present application is compatible with the legacy version of UE.

[0245] In the above Figure 8 , Fig. 9 and Fig.10 In the corresponding embodiment, since the first IAB node changes the IAB host, the PCI of the first IAB node may change. If the PCI of the first IAB node changes, the second node may not be able to correctly receive the Figure 8 , Fig. 9 The first message or the second indication information in Fig.10 To this end, the present application also provides a method for updating PCI, through which the second node can correctly receive the first message, the second indication information, or the third message. The method can be used together with the above Figure 8 , Fig. 9 and Fig.10 The method is described below by taking the first message as an example. Fig.11 , Fig.11 Schematic diagram of the process of updating PCI in an embodiment of the present application.

[0246] In step 1101, the first IAB node sends an update notification to the second node, where the update notification is used to indicate that system information is updated, or is used to indicate that a PCI is about to be updated.

[0247] In step 1102, the first IAB node broadcasts the updated PCI of the first IAB node (for example, the updated PCI is carried in system information).

[0248] The physical cell identifier PCI is used to distinguish wireless signals of different cells to ensure that there is no identical physical cell identifier within the coverage of the relevant cells. The PCI can be used to scramble the first message to be sent.

[0249] In step 1103, the second node obtains the updated PCI broadcasted by the first IAB node according to the update notification, and correctly receives the first message according to the updated PCI.

[0250] The first IAB node uses a new PCI as an input parameter of the scrambling codeword in data transmission that requires PCI scrambling. Therefore, when the PCI changes, the second node needs to perceive the change in PCI, otherwise it will not be able to correctly receive the first message sent by the first IAB node. Generally, the second node will only actively obtain the PCI of the cell when performing a cell search. In an embodiment of the present application, before the first IAB node restores the RRC connection with the target IAB node by executing RLF, the second node is connected to the source IAB node through the first IAB node. Therefore, if the second node does not re-perform a cell search, it will not be able to perceive the updated PCI of the first IAB node. To this end, the second node actively obtains the updated PCI broadcasted by the first IAB node through the update notification sent by the first IAB node, and performs reception processing (such as descrambling) on ​​the received first message according to the updated PCI, thereby correctly receiving the first message.

[0251] The above describes the RLF recovery method of the IAB network and the PCI update method in the embodiment of the present application. The following describes the RLF recovery device of the IAB network in the embodiment of the present application. Fig.12 , Fig.12 It is a structural diagram of a RLF recovery device of an IAB network in an embodiment of the present application.

[0252] The apparatus includes: an establishing module 1201, configured to establish a radio resource control RRC connection with a target IAB host by performing RLF recovery;

[0253] The sending module 1202 is used to send a first message to the second node through SRB1 or SRB2 after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, or the first IAB node sends a backhaul link radio link failure indication BH RLF indication to the second node. The first message is used to establish an RRC connection between the second node and the target IAB host. Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0254] In other embodiments, the device may also include a receiving module or a broadcasting module. The module in the device is specifically used to perform the above Figure 6 , Figure 8 or Fig. 9 The first IAB node 3 in the corresponding embodiment may perform all or part of the operations.

[0255] See also Fig.12 , Fig.12It is a structural diagram of a RLF recovery device of an IAB network in an embodiment of the present application.

[0256] The apparatus includes: an establishing module 1201, configured to establish a radio resource control RRC connection with a target IAB host by performing RLF recovery;

[0257] The sending module 1202 is used to send a first message to the second node through the signaling radio bearer SRB1 or SRB2 after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, or the first IAB node sends a backhaul link radio link failure indication BH RLF indication to the second node. The first message or BH RLF indication is used to establish an RRC connection between the second node and the target IAB host. Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0258] In other embodiments, the device may also include a receiving module or a broadcasting module. The module in the device is specifically used to perform the above Figure 6 , Figure 8 or Fig. 9 The first IAB node 3 in the corresponding embodiment may perform all or part of the operations.

[0259] See also Fig.13 , Fig.13 Another structural diagram of the RLF recovery device of the IAB network in the embodiment of the present application.

[0260] The device includes: a sending module 1301, which is used to send a second message to a first IAB node, where the second message is used by the first IAB node to send the first message to the second node through a signaling radio bearer SRB1 or SRB2 according to the second message, or is used by the first IAB node to send a backhaul link radio link failure indication BH RLF indication to the second node. Before the first IAB node establishes an RRC connection with a target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0261] In other embodiments, the device may further include a receiving module, etc. The module in the device is specifically used to perform the above Figure 6 , Figure 8 or Fig. 9 The target IAB host in the corresponding embodiment may perform all or part of the operations.

[0262] See also Fig.14 , Fig.14 Another structural diagram of the RLF recovery device of the IAB network in the embodiment of the present application.

[0263] The device includes: a receiving module 1401, configured to receive a context acquisition request from a target IAB host;

[0264] The sending module 1402 is used to send a context acquisition response to the target IAB host, where the context acquisition response includes an identifier of the second node, and the identifier of the second node is used by the first IAB node to send a first message to the second node according to the identifier of the second node, and the first message is used by the second node to establish an RRC connection with the target IAB host. Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the device through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0265] In other embodiments, the module in the device is specifically used to perform the above Figure 8 or Fig. 9 The source IAB host in the corresponding embodiment may perform all or part of the operations.

[0266] See also Fig.15 , Fig.15 It is a structural diagram of an RRC reconfiguration device of an IAB network in an embodiment of the present application.

[0267] The apparatus comprises: a first sending module 1501, configured to send a first RRC reconfiguration message to a source IAB host;

[0268] The receiving module 1502 is configured to receive a third message from the source IAB host, where the third message is the RRC reconfiguration message after the first RRC reconfiguration message is encrypted and / or integrity protected;

[0269] The second sending module 1503 is used to send a third message to the second node through the first IAB node. Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node. The second node is a child node or a subordinate UE of the first IAB node.

[0270] In other embodiments, the module in the device is specifically used to perform the above Fig.10 The target IAB host in the corresponding embodiment may perform all or part of the operations.

[0271] See also Fig.16 , Fig.16Another structural diagram of the RRC reconfiguration device of the IAB network in the embodiment of the present application.

[0272] The apparatus includes: a receiving module 1601, configured to receive a first RRC reconfiguration message from a target IAB host;

[0273] The sending module 1602 is used to send a third message to the target IAB host, where the third message is the RRC reconfiguration message after the first RRC reconfiguration message is encrypted and / or integrity protected. The third message is used for the target IAB host to send the third message to the second node through the first IAB node. Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0274] In other embodiments, the module in the device is specifically used to perform the above Fig.10 The source IAB host in the corresponding embodiment may perform all or part of the operations.

[0275] See also Fig.17 , Fig.17 A structural diagram of a device for updating PCI in an embodiment of the present application.

[0276] The apparatus comprises: a sending module 1701, configured to send an update notification to a second node;

[0277] The broadcast module 1702 is used to broadcast the updated physical cell identifier PCI of the first IAB node, wherein the update notification is used to instruct the second node to obtain the updated PCI, and the updated PCI is used for the second node to correctly receive the first message, or the BH RLF indication, or the third message.

[0278] In other embodiments, the module in the device is specifically used to perform the above Figure 6 , Figure 8 , Fig. 9 , Fig.10 or Fig.11 The first IAB node in the corresponding embodiment may perform all or part of the operations.

[0279] See also Fig.18 , Fig.18 Another structural diagram of the device for updating PCI in an embodiment of the present application.

[0280] The apparatus comprises: a first receiving module 1801, configured to receive an update notification from a first IAB node;

[0281] The second receiving module 1802 is configured to receive a physical cell identifier PCI updated by the first IAB node from the first IAB node according to the update notification;

[0282] The third receiving module 1803 is configured to receive the first message, or the BH RLFindication, or the third message according to the updated PCI.

[0283] In other embodiments, the module in the device is specifically used to perform the above Figure 6 , Figure 8 , Fig. 9 , Fig.10 ,or Fig.11 The second node in the corresponding embodiment may perform all or part of the operations.

[0284] The RLF recovery device of the IAB network and the device for updating PCI in the embodiment of the present application are described above. The RLF recovery device of the IAB network in the embodiment of the present application is described below.

[0285] See also Fig.19 , Fig.19 It is a structural schematic diagram of a communication device in an embodiment of the present application.

[0286] The communication device 1900 includes one or more processors 1901, which can support the communication device 1900 to implement Figures 6 to 10 The communication method in. The processor 1901 may be a general-purpose processor or a special-purpose processor. For example, the processor 1901 may be a central processing unit (CPU) or a baseband processor. The baseband processor may be used to process communication data, and the CPU may be used to control a communication device (e.g., a network device, a terminal device, or a chip), execute a software program, and process data of the software program. The communication device 1900 may include one or more memories 1902, on which a program 1904 is stored. The program 1904 may be run by the processor 1901 to generate an instruction 1903, so that the processor 1901 executes the method described in the above method embodiment according to the instruction 1903. Optionally, data may also be stored in the memory 1902. Optionally, the processor 1901 may also read data stored in the memory 1902, and the data may be stored at the same storage address as the program 1904, or the data may be stored at a different storage address than the program 1904.

[0287] The processor 1901 and the memory 1902 may be provided separately or integrated together, for example, integrated on a single board or a system on chip (SOC).

[0288] The device 1900 may also include a transceiver unit 1905 to implement signal input (reception) and output (transmission). The transceiver unit 1905 may be called a transceiver, a transceiver circuit, or a transceiver. Specifically, the transceiver unit 1905 implements signal input (reception) and output (transmission) through an antenna 1906.

[0289] In an optional manner, the device 1900 may be used to implement the method described in the above method embodiment regarding the first IAB node, for example, Figure 6 , Figure 8 , Fig. 9 , Fig.10 ,or Fig.11 All or part of the operations that can be performed by the first IAB node in the process. For example, the processor 1901 is used to establish a radio resource control RRC connection with the target IAB host by performing RLF recovery; the transceiver unit 1905 is used to send a first message to the second node through SRB1 or SRB2 after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, or the first IAB node sends a backhaul link radio link failure indication BH RLF indication to the second node, the first message is used to establish an RRC connection between the second node and the target IAB host, before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0290] In an optional manner, the communication device 1900 may be used to implement the method described in the above method embodiment regarding the target IAB host node, for example, Figure 6 , Figure 8 , Fig. 9 ,or Fig.10 All or part of the operations that can be performed by the target IAB host in the message. For example, the transceiver unit 1905 is used to send a second message to the first IAB node, and the second message is used for the first IAB node to send the first message to the second node through SRB1 or SRB2 according to the second message, or for the first IAB node to send a backhaul link radio link failure indication BH RLF indication to the second node. Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0291] In an optional manner, the communication device 1900 may be used to implement the method described in the above method embodiment regarding the source IAB host, for example, Figure 6 , Figure 8 , Fig. 9 ,or Fig.10 All or part of the operations that can be performed by the source IAB host in the source IAB host. For example, the transceiver unit 1905 is used to receive a context acquisition request from a target IAB host; send a context acquisition response to the target IAB host, the context acquisition response includes an identifier of a second node, the identifier of the second node is used by the first IAB node to send a first message to the second node according to the identifier of the second node, the first message or BH RLFindication is used by the second node to establish an RRC connection with the target IAB host, before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the device through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0292] In an optional manner, the communication device 1900 may be used to implement the method regarding the second node described in the above method embodiment, for example, Figure 6 , Figure 8 , Fig. 9 , Fig.10 ,or Fig.11 For example, the transceiver unit 1905 is used to receive an update notification from the first IAB node; receive, according to the update notification, the updated physical cell identifier PCI of the first IAB node sent by the first IAB node; and receive, according to the updated PCI, a first message, or a BH RLF indication, or a third message.

[0293] The device 1900 may be a chip. For example, the transceiver unit 1905 may be an input and / or output circuit of the chip, or the transceiver unit 1905 may be a communication interface of the chip, and the chip may be a component of a terminal device, a network device, or other wireless communication device.

[0294] It should be understood that each step of the above method embodiment can be completed by a hardware-based logic circuit or a software-based instruction in the processor 1901. The processor 1901 can be a CPU, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, such as discrete gates, transistor logic devices, or discrete hardware components.

[0295] See also Fig. 20 , Fig. 20 Another structural diagram of a communication device provided in an embodiment of the present application.

[0296] The communication device 200 may be the above Figure 6 , Figure 8 , Fig. 9 ,or Fig.10 The communication device 200 may adopt a CU-DU separation architecture. Fig. 20 As shown, the communication device 200 can be applied to Figure 1 , Figure 2 , Figure 5 or Figure 7 In the illustrated scenario, the functions of the IAB host (source IAB host and / or target IAB host) in the above method embodiment are implemented.

[0297] The communication device 200 may include one or more DUs 2001 and one or more CUs 2002. The DU 2001 may include at least one antenna 20011, at least one radio frequency unit 20012, at least one processor 20013 and at least one memory 20014. The DU 2001 is mainly used for receiving and transmitting radio frequency signals, converting radio frequency signals to baseband signals, and part of baseband processing. The CU 2002 may include at least one processor 20022 and at least one memory 20021. The CU 2002 and the DU 2001 may communicate through an interface, wherein the control plane interface may be F1-C and the user plane interface may be F1-U.

[0298] The CU 2002 part is mainly used for baseband processing, controlling the base station, etc. The DU 2001 and CU 2002 can be physically set together or physically separated, that is, a distributed base station. The CU 2002 is the control center of the base station, which can also be called a processing unit, and is mainly used to complete the baseband processing function. For example, the CU 2002 can be used to control the base station to execute the operation process of the network device in the above method embodiment.

[0299] Specifically, the baseband processing on the CU and DU can be divided according to the protocol layer of the wireless network, and the details can be referred to the above content.

[0300] In one example, the CU 2002 may be composed of one or more boards, and the multiple boards may jointly support a wireless access network with a single access indication (such as a 5G network), or may respectively support wireless access networks with different access standards (such as an LTE network, a 5G network, or other access networks). The memory 20021 and the processor 20022 may serve one or more boards. In other words, a memory and a processor may be separately set on each board. It may also be that multiple boards share the same memory and processor. In addition, necessary circuits may be set on each board. The DU 2001 may be composed of one or more boards, and the multiple boards may jointly support a wireless access network with a single access indication (such as a 5G network), or may respectively support wireless access networks with different access standards (such as an LTE network, a 5G network, or other access networks). The memory 20014 and the processor 20013 may serve one or more boards. In other words, a memory and a processor may be separately set on each board. It may also be that multiple boards share the same memory and processor. In addition, necessary circuits may also be set on each board.

[0301] Optionally, CU 2002 can transmit with the sub-nodes of the access network device through DU 2001, CU 2002 can be connected to other access network devices through an interface, CU 2002 can receive data and / or messages from other access network devices (e.g., CUs of other access network devices) through the interface, or CU 2002 can send data and / or messages to the other access network devices through the interface.

[0302] For example, in the above Fig. 9 In a corresponding embodiment, when the communication device 200 is a target IAB host, the CU of the target IAB host is connected to the first IAB node through the DU and the antenna. The CU of the target IAB host sends a second message to the MT of the first IAB node through the DU and the antenna, and the second message is used by the first IAB node to send the first message to the second node through the signaling radio bearer SRB1 or SRB2 according to the second message, or is used by the first IAB node to send a BH RLF indication to the second node; wherein, before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate UE of the first IAB node.

[0303] For example, in the above Fig.10In the corresponding embodiment, when the communication device 200 is the target IAB host, the CU of the target IAB host is connected to the CU of the source IAB host. The CU of the target IAB host sends a first RRC reconfiguration message to the CU of the source IAB host; the CU of the target IAB host receives a third message from the CU of the source IAB host, and the third message is an RRC reconfiguration message after the first RRC reconfiguration message is encrypted and / or integrity protected; the CU of the target IAB host is also connected to the first IAB node through the DU, antenna, and the CU of the target IAB host is also sent to the first IAB node through the DU, antenna; wherein, before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or subordinate UE of the first IAB node.

[0304] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0305] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0306] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0307] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as flash drives, mobile hard drives, ROM, RAM, magnetic disks or optical disks.

Claims

1. A method for recovering a radio link failure RLF in an integrated backhaul IAB network, characterized in that: include: The first IAB node establishes a radio resource control RRC connection with the target IAB host by performing RLF recovery; After the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the first IAB node sends a first message to the second node through a signaling radio bearer SRB1 or SRB2, or the first IAB node sends a backhaul link radio link failure indication BH RLF indication to the second node, and the first message or the BHRLF indication is used to establish an RRC connection between the second node and the target IAB host; Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate user equipment UE of the first IAB node.

2. The method according to claim 1, characterized in that The first message is an RRC message. Before the first IAB node sends the first message to the second node, after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the method further includes: The first IAB node receives a second message from the target IAB host, where the second message includes an SRB identifier and the RRC message, and the SRB identifier includes an identifier of the SRB1 and / or the SRB2.

3. The method according to claim 1, characterized in that Before the first IAB node sends the first message to the second node, the method further includes: The first IAB node receives a second message from the target IAB host, where the second message includes first indication information; The first IAB node sending the BH RLF indication to the second node includes: The first IAB node sends the BH RLFindication to the second node according to the first indication information.

4. The method according to claim 3, characterized in that The second message is an RRC re-establishment message.

5. The method according to claim 3 or 4, characterized in that: The first indication information is used to indicate that the RRC re-establishment performed by the first IAB node is an RRC re-establishment across IAB hosts.

6. The method according to any one of claims 1 to 5, characterized in that: Before the first IAB node sends the first message to the second node through the signaling radio bearer SRB1 or SRB2, or before the first IAB node sends the BH RLF indication to the second node, the method further includes: The first IAB node sends an update notification to the second node; The first IAB node broadcasts the updated physical cell identity PCI of the first IAB node, and the update notification is used to instruct the second node to obtain the updated PCI, and the updated PCI is used for the second node to correctly receive the first message, or the BH RLF indication.

7. A method for recovering a radio link failure RLF in an integrated backhaul IAB network, characterized in that: include: The target IAB host sends a second message to the first IAB node, where the second message is used by the first IAB node to send the first message to the second node through the signaling radio bearer SRB1 or SRB2 according to the second message, or is used by the first IAB node to send a backhaul link radio link failure indication BH RLF indication to the second node; Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate user equipment UE of the first IAB node.

8. The method according to claim 7, characterized in that The first message is an RRC message, the second message includes an SRB identifier and the RRC message, and the SRB identifier includes an identifier of the SRB1 and / or the SRB2; The target IAB host sending the second message to the first IAB includes: After the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the target IAB host sends the second message to the first IAB.

9. The method according to claim 7, characterized in that: The second message is an RRC re-establishment message. The RRC re-establishment message includes first indication information, where the first indication information is used by the first IAB node to send the BH RLF indication to the second node according to the first indication information.

10. The method according to claim 9, characterized in that The first indication information is used to indicate that the RRC re-establishment performed by the first IAB node is an RRC re-establishment across IAB hosts.

11. The method according to claim 8, characterized in that The second message also includes an identifier of the second node. Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the method further includes: The target IAB host sends a context acquisition request to the source IAB host; The target IAB host receives a context acquisition response from the source IAB host, where the context acquisition response includes an identifier of the second node.

12. An RRC reconfiguration method for accessing an integrated backhaul IAB network, characterized in that: include: The target IAB host sends a first RRC reconfiguration message to the source IAB host; The target IAB host receives a third message from the source IAB host, where the third message is the RRC reconfiguration message after the first RRC reconfiguration message is encrypted and / or integrity protected; The target IAB host sends the third message to the second node through the first IAB node; Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate user equipment UE of the first IAB node.

13. The method according to claim 12, characterized in that The third message includes a random access-free indication.

14. The method according to claim 12 or 13, characterized in that The third message is a switching command.

15. An RRC reconfiguration method for accessing an integrated backhaul IAB network, characterized in that: include: The source IAB host receives a first RRC reconfiguration message from the target IAB host; The source IAB host sends a third message to the target IAB host, where the third message is the RRC reconfiguration message after the first RRC reconfiguration message is encrypted and / or integrity protected; Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate user equipment UE of the first IAB node.

16. The method according to claim 15, characterized in that The third message includes a random access-free indication.

17. The method according to claim 15 or 16, characterized in that The third message is a switching command.

18. A radio link failure RLF recovery device for an integrated backhaul IAB network, characterized in that: include: An establishing module, configured to establish a radio resource control RRC connection with a target IAB host by performing RLF recovery; a sending module, configured to send a first message to a second node through a signaling radio bearer SRB1 or SRB2, or send a backhaul link radio link failure indication BH RLF indication to the second node after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, wherein the first message or the BH RLF indication is used to establish an RRC connection between the second node and the target IAB host, Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate user equipment UE of the first IAB node.

19. The device according to claim 18, characterized in that The first message is an RRC message, and the device further includes: The receiving module is configured to receive a second message from the target IAB host, where the second message includes an SRB identifier and the RRC message, and the SRB identifier includes an identifier of the SRB1 and / or the SRB2.

20. The device according to claim 18, characterized in that The device also includes: A receiving module, configured to receive a second message from the target IAB host, where the second message includes first indication information; The sending module is specifically configured to send the BH RLFindication to the second node according to the first indication information.

21. The device according to claim 20, characterized in that The second message is an RRC re-establishment message.

22. The device according to claim 20 or 21, characterized in that The first indication information is used to indicate that the RRC re-establishment performed by the device is an RRC re-establishment across IAB hosts.

23. The device according to any one of claims 18 to 22, characterized in that The sending module is further used to send an update notification to the second node; The device also includes: A broadcast module is used to broadcast the updated physical cell identifier PCI of the first IAB node, wherein the update notification is used to instruct the second node to obtain the updated PCI, and the updated PCI is used for the second node to correctly receive the first message, or the BH RLF indication.

24. A radio link failure RLF recovery device for an integrated backhaul IAB network, characterized in that: include: a sending module, configured to send a second message to a first IAB node, wherein the second message is used by the first IAB node to send the first message to the second node through a signaling radio bearer SRB1 or SRB2 according to the second message, or to send a backhaul link radio link failure indication BH RLF indication to the second node; Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate user equipment UE of the first IAB node.

25. The device according to claim 24, characterized in that The first message is an RRC message, the second message includes an SRB identifier and the RRC message, and the SRB identifier includes an identifier of the SRB1 and / or the SRB2; The sending module is specifically configured to send the second message to the first IAB after the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery.

26. The device according to claim 24, characterized in that The second message is an RRC re-establishment message, and the RRC re-establishment message includes first indication information, where the first indication information is used by the first IAB node to send the BH RLF indication to the second node according to the first indication information.

27. The device according to claim 26, characterized in that The first indication information is used to indicate that the RRC re-establishment performed by the first IAB node is an RRC re-establishment across IAB hosts.

28. The device according to claim 25, characterized in that The second message also includes an identifier of the second node; The sending module is further used to send a context acquisition request to the source IAB host; The device also includes: The receiving module is configured to receive a context acquisition response from the source IAB host, where the context acquisition response includes an identifier of the second node.

29. An RRC reconfiguration device for accessing an integrated backhaul IAB network, characterized in that: include: A first sending module, configured to send a first RRC reconfiguration message to a source IAB host; A receiving module, configured to receive a third message from the source IAB host, where the third message is the RRC reconfiguration message after the first RRC reconfiguration message is encrypted and / or integrity protected; A second sending module, configured to send the third message to the second node through the first IAB node; Before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate user equipment UE of the first IAB node.

30. The device according to claim 29, characterized in that The third message includes a random access-free indication.

31. The device according to claim 29 or 30, characterized in that The third message is a switching command.

32. An RRC reconfiguration device for accessing an integrated backhaul IAB network, characterized in that: include: A receiving module, configured to receive a first RRC reconfiguration message from a target IAB host; a sending module, configured to send a third message to the target IAB host, wherein the third message is an RRC reconfiguration message after the first RRC reconfiguration message is encrypted and / or integrity protected, and the third message is used for a second node to establish an RRC connection with the target IAB host through a first IAB node, and before the first IAB node establishes an RRC connection with the target IAB host by performing RLF recovery, the second node is connected to the source IAB host through the first IAB node, and the second node is a child node or a subordinate user equipment UE of the first IAB node.

33. The device according to claim 32, characterized in that The third message includes a random access-free indication.

34. The device according to claim 32 or 33, characterized in that The third message is a switching command.

35. A communication device, characterized in that: include: A processor, wherein the processor is used to execute the method of any one of claims 1-6, or the method of any one of claims 7-11, or the method of any one of claims 12-14, or the method of any one of claims 15-17.

36. A communication device, characterized in that: include: A processor and a memory, wherein the processor is used to call and run a computer program from the memory to execute the method of any one of claims 1 to 6, or to execute the method of any one of claims 7 to 11, or to execute the method of any one of claims 12 to 14, or to execute the method of any one of claims 15 to 17.

37. A chip, characterized in that: The chip includes a processor and a data interface, and the processor reads program instructions stored in the memory through the data interface to execute the method described in any one of claims 1 to 6, or the method described in any one of claims 7 to 11, or the method described in any one of claims 12 to 14, or the method described in any one of claims 15 to 17.

38. An IAB network system integrating access and backhaul, characterized in that: It includes a first IAB node, a second node, a source IAB host, and a target IAB host; The first IAB node is used to perform the method as described in any one of claims 1 to 6; The target IAB host is used to perform the method as claimed in any one of claims 7 to 11.

39. An IAB network system integrating access and backhaul, characterized in that: It includes a first IAB node, a second node, a source IAB host, and a target IAB host; The target IAB host is used to perform the method as described in any one of claims 12 to 14; The source IAB host is used to perform the method as claimed in any one of claims 15 to 17.

40. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program for execution by a device, wherein the computer program includes a method for executing any one of claims 1-6, or a method for executing any one of claims 7-11, or a method for executing any one of claims 12-14, or a method for executing any one of claims 15-17.

41. A computer program product, comprising a computer program, which, when executed on a computer device, causes the computer device to execute the method of any one of claims 1 to 6, or the method of any one of claims 7 to 11, or the method of any one of claims 12 to 14, or the method of any one of claims 15 to 17.

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