Communication method and related apparatus

Abstract

A communication method and a related apparatus, relating to the technical field of communications. The method comprises: when a first trigger condition is satisfied, a relay node releases a configuration of a backhaul link. The backhaul link is a backhaul link between the relay node and a first donor node. The method clearly provides the trigger condition for releasing the configuration of the backhaul link. Thus, the relay node can release the configuration of the backhaul link in a timely fashion when the first trigger condition is satisfied, so that the configuration of the backhaul link which is not used temporarily is released, and can be used by other nodes, thereby increasing the resource utilization rate. In addition, in the embodiments of the present application, a situation in which two backhaul links are allocated to an IAB node can be avoided, so that conflicts in backhaul link configuration can be avoided, and signaling overhead in an MT migration process can be reduced.

Description

Communication methods and related devices

[0001] This application claims priority to Chinese Patent Application No. 202311288668.6, filed with the China National Intellectual Property Administration on September 27, 2023, entitled "Communication Method and Related Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a communication method and related apparatus. Background Technology

[0003] Compared to fourth-generation mobile communication systems, fifth-generation (5G) and future mobile communication systems place more stringent demands on network performance indicators. For example, 5G offers 1000 times the capacity of 4G, wider coverage, and ultra-high reliability and ultra-low latency. On one hand, given the abundance of high-frequency carrier resources, the use of high-frequency small cell networks is becoming increasingly popular in hotspot areas to meet the ultra-high capacity requirements of 5G. However, due to the poor propagation characteristics of high-frequency carriers and severe attenuation caused by obstruction, coverage is limited, necessitating a large-scale, dense deployment of small cells. However, providing fiber optic backhaul for these densely deployed small cells is costly and difficult to implement, thus requiring an economical and convenient backhaul solution. On the other hand, from the perspective of wide coverage requirements, providing network coverage in remote areas presents significant challenges and costs associated with fiber optic deployment, necessitating the design of flexible and convenient access and backhaul solutions. Integrated access and backhaul (IAB) technology offers a solution to the two problems mentioned above: both its access link and backhaul link (BL) use wireless transmission schemes, reducing the need for fiber optic deployment.

[0004] In an IAB network, a relay node (RN), also called an IAB node, provides radio access services and forwards service data to user equipment (UE). UE service data is transmitted from the IAB node to the IAB donor (also called a host node or host base station (donor gNodeB, DgNB)) via a radio backhaul link. An IAB node consists of a mobile termination (MT) component and a distributed unit (DU) component. When an IAB node faces its parent node, it acts as a terminal device (MT); when it faces its child node (which could be another IAB node or a UE), it is considered a network device (DU). The host base station (DgNB) can be an access network element with full base station functionality, or it can be an access network element with separate centralized unit (CU) and distributed unit (DU) components. The host base station connects to the core network elements that serve the UE (e.g., connects to the 5G core network) and provides wireless backhaul functionality for the IAB nodes.

[0005] In an IAB network, during the MT migration process of an IAB node, the target CU will allocate backhaul link configurations to the IAB node by default, such as the default backhaul adaptation protocol (BAP) configuration, BAP address, and IP address. After the MT migration is complete, when the IAB node changes from an unauthorized state to an authorized state, it will also obtain the backhaul link configurations again. If the IAB node is in an unauthorized state after the MT migration and subsequently changes to an authorized state, it may encounter the problem of having two sets of backhaul link configurations, increasing signaling overhead.

[0006] Summary of the Invention

[0007] This application provides a communication method and related apparatus that can reduce signaling overhead during IAB node MT migration.

[0008] In this application, the CU (or host) connected to the MT and the CU (or host) connected to the DU refer to logical connections, not physical direct connections. For example, the MT has a radio resource control (RRC) connection with the CU it is connected to, and the DU has an F1 interface connection with the CU it is connected to. Furthermore, the logical connection may be in a state of impending establishment (e.g., the DU has determined to establish an F1 connection with a CU, but the F1 interface has not yet been established and is about to initiate F1 interface establishment) or in a state of already established establishment (e.g., the DU has already established an F1 interface with the CU it is connected to). In this application, the migration of a relay node typically refers to the migration of the DU within the relay node.

[0009] Firstly, embodiments of this application provide a communication method, which can be executed by a communication device. The communication device can be a machine, or a chip (system) or circuit used in a machine; this application does not limit its scope. The method is applied to a relay node and includes:

[0010] When the first triggering condition is met, the relay node releases the configuration of the backhaul link; the backhaul link is the backhaul link between the relay node and the first host node.

[0011] The first triggering condition includes:

[0012] The relay node performs mobile terminal (MT) migration; and, the relay node is in an unauthorized state; and, the relay node receives first configuration information from the first host node, the first configuration information being used to indicate the configuration of the backhaul link.

[0013] This application provides a communication method in which, upon meeting a first triggering condition, a relay node releases the configuration of a backhaul link, which is a backhaul link between the relay node and a first host node. The first triggering condition includes the relay node being in an unauthorized state. This allows backhaul link configurations that are not currently used by the relay node to be released promptly and potentially used by other nodes, reducing resource waste and improving resource utilization.

[0014] The relay node in this application can be a device equipped with a processor / chip capable of executing computer-executed instructions, or it can be a processor / chip capable of executing computer-executed instructions. The relay node in this application includes a terminal-side portion facing the parent node and a network-side portion facing the child node. For example, it can include MT and DU, or it can include MT and gNB; this application does not limit this. The migration of the DU and MT of the relay node is completely decoupled; therefore, the host node connected to the MT of the relay node and the host node connected to the DU can be different or the same. For example, both the MT and DU of the relay node are connected to the first host node; another example is that the MT of the relay node is connected to the second host node, and the DU of the relay node is connected to the first host node. When the communication method in this application is applied to an IAB network, the relay node can be an IAB node, the MT of the IAB node is connected to the first host node, and the host node connected to the DU of the IAB node is not limited in this application; for example, it can be the first host node or the second host node, etc.

[0015] In this application's embodiments, the first host node can be a device equipped with a processor / chip capable of executing computer-executed instructions, or it can be a processor / chip capable of executing computer-executed instructions. In this application's embodiments, the first host node is the target CU corresponding to the relay node's MT. After the relay node performs MT migration, the first host node connects to the relay node's MT. When the communication method in this application's embodiments is applied to an IAB network, the relay node can be an IAB node, and the first host node can connect to the IAB node's MT.

[0016] The second host node in this application embodiment can be a device equipped with a processor / chip capable of executing computer execution instructions, or it can be a processor / chip capable of executing computer execution instructions. In this application embodiment, the second host node is the host node before the MT migration. When the communication method in this application embodiment is applied to an IAB network, the relay node can be an IAB node, and the second host node can connect to the MT of the IAB node.

[0017] The release of the backhaul link configuration in this embodiment can be understood as the backhaul link configuration failing, or the configuration not being used, or the backhaul link configuration not being used, or the backhaul link having already been built based on the configuration, and then releasing the already built backhaul link. Releasing the backhaul link configuration should not be understood solely as the backhaul link having already been built based on the configuration, and then releasing the already built backhaul link. Optionally, after the relay node releases the backhaul link configuration, it can send a message, such as an RRC message, to the first host node to inform the first host node that the relay node has released the backhaul link configuration, or to trigger the first host node to release the backhaul link configuration. Upon receiving the message, if the first host node has not yet released the backhaul link configuration, it will release the backhaul link configuration.

[0018] The first triggering condition in this application's embodiments includes, but is not limited to: the relay node performing MT migration; the relay node being in an unauthorized state; and the relay node receiving first configuration information from the first host node, the first configuration information being used to indicate the configuration of the backhaul link.

[0019] In this context, relay node performing MT migration can refer to the process after the first host node receives information instructing MT migration, for example, after the first host node receives MT migration instruction information from the second host node (e.g., a HANDOVER REQUEST message).

[0020] The term "unauthorized state" for a relay node can refer to the relay node being unauthorized under the second host node, the relay node being unauthorized under the first host node, or the relay node being only allowed to be in an unauthorized state under the current circumstances (e.g., a specific time period or a specific space). This application does not impose any restrictions on this.

[0021] A relay node being in an unauthorized state can also be understood as the relay node being about to be determined to be in an unauthorized state, or the relay node being indicated to be in an unauthorized state by other indication information, etc.

[0022] For example, the handover request message sent by the second host node to the first host node includes information indicating that the relay node is in an unauthorized state.

[0023] For example, the access and mobility management function (AMF) sends information to the first host node indicating that the relay node is in an unauthorized state. Specifically, the AMF sends a PATH SWITCH REQUEST ACK message to the first host node, carrying relay node authorization information indicating that the relay node is in an unauthorized state.

[0024] For example, the AMF directly sends information to the MT of the relay node indicating that the relay node is in an unauthorized state. Specifically, the AMF sends a NAS message to the MT of the relay node. This NAS message carries information about the authorized state of the MT of the relay node, and this authorized state information indicates that the MT of the relay node is in an unauthorized state.

[0025] The first configuration information indicates the configuration of the backhaul link, which is a backhaul link between the relay node and the first host node. This backhaul link configuration is used to establish the backhaul link for communication. The backhaul link configuration may include one or more of the following: default BAP configuration, BAP address, and IP address, etc.

[0026] Optionally, the aforementioned first configuration information can be carried in an RRC message, such as the RRC reconfiguration message RRCReconfiguration.

[0027] In an IAB network, during the MT migration process of an IAB node, the target CU will by default allocate backhaul link configurations to the IAB node, including one or more of the following: default BAP configuration, BAP address, and IP address. After the MT migration is completed, when the IAB node changes from an unauthorized state to an authorized state, it will perform a network entry procedure and also obtain backhaul link configurations. For example, during the migration of an IAB node's MT to the first host node, the first host node usually defaults to an authorized state for the IAB node's MT and allocates backhaul link configurations to the IAB node's MT. After the MT handover of the IAB node is completed, the AMF will send the IAB node's authorization information (including authorized or unauthorized state) to the first host node. For example, the NAS message sent by the AMF to the IAB node carries the IAB node's authorization information. This authorization information can be an IAB Authorized cell or a Mobile IAB Authorized cell (hereinafter referred to as mIAB Authorized cell), which is not limited in this embodiment.

[0028] If the MT (Mobile Transport) of an IAB node is in an unlicensed state, how to handle the backhaul link configuration already assigned to that MT is a problem that needs to be solved. Furthermore, if the MT of an IAB node subsequently changes from an unlicensed state to a licensed state, the IAB node will re-enter the network and obtain a new backhaul link configuration. Whether the IAB node uses the new or old backhaul link configuration at this time is also a problem that needs to be addressed. At the same time, allocating two sets of backhaul link configurations to the IAB node may also cause usage conflicts and increase signaling overhead.

[0029] However, in this application's implementation, the triggering conditions for releasing backhaul link configurations are explicitly provided. This ensures that, upon meeting the first triggering condition, the relay node will promptly release the backhaul link configurations, allowing temporarily unused backhaul link configurations to be used by other nodes, thus improving resource utilization. Furthermore, since this implementation also avoids allocating two sets of backhaul link configurations to IAB nodes, it can prevent backhaul link configuration conflicts and reduce signaling overhead during MT migration.

[0030] In one possible implementation, the backhaul link configuration is not released under the following triggering conditions: the relay node performs a mobile terminal (MT) migration; the relay node is in an authorized state; and the relay node receives first configuration information from the first host node, the first configuration information indicating the configuration of the backhaul link.

[0031] In one possible implementation of the first aspect, the first configuration information includes at least one of the following: a default Backhaul Link Adaptation Layer Protocol (BAP) configuration, a BAP address, and an Internet Protocol (IP) address.

[0032] In this application embodiment, a possible specific implementation of the first configuration is provided. Specifically, in the MT migration scenario of the IAB node, the first host node sends a first configuration to the IAB node. The first configuration may include at least one of the following: default BAP configuration, BAP address, and IP address, etc. It should be noted that the first configuration information may be carried in one RRC message or in multiple RRC messages; this application embodiment does not limit this.

[0033] In another possible implementation of the first aspect, the method further includes:

[0034] When the relay node switches to authorized state, it receives second configuration information from the first host node, the second configuration information being used to indicate the configuration of the backhaul link.

[0035] The relay node switching to an authorized state can refer to the AMF sending an indication message to the first host node, indicating that the relay node is in an authorized state. This indication message can be carried by the PATH SWITCH REQUEST ACK message in the handover procedure. Alternatively, this indication message can be carried by the UE CONTEXT MODIFICATION REQUEST message. It can also refer to the AMF sending a Non-Access Stratum (NAS) message to the MT of the IAB node, indicating that the IAB node is in an authorized state. Furthermore, it can refer to the NAS layer of the IAB node sending an indication message to the AS layer, indicating that the IAB node is in an authorized state. This embodiment of the application does not limit which specific instance of the relay node switching to an authorized state refers to.

[0036] Optionally, the message indicating the authorization status of the relay node can be an IAB Authorized message or a mIAB Authorized message; this embodiment of the application does not limit this.

[0037] In this process, the relay node receives second configuration information from the first host node, and correspondingly, the first host node generates / sends second configuration information. The second configuration information is the configuration information for the backhaul link, which is the backhaul link between the relay node and the first host node.

[0038] Optionally, the second configuration information includes at least one of the following: default BAP configuration, BAP address, and Internet Protocol (IP) address. This application does not limit the implementation of this method.

[0039] It should be noted that the second configuration information can be carried in one RRC message or in multiple RRC messages; this application embodiment does not limit this.

[0040] This application provides a possible implementation of a relay node. Specifically, in a scenario where a relay node switches from an unauthorized state to an authorized state, the relay node receives second configuration information from the first host node to construct a backhaul link for communication. It is understood that in this application embodiment, if the relay node is in an unauthorized state, the configuration information (first configuration information) allocated to the relay node will be released. Switching from an unauthorized state to an authorized state avoids the simultaneous existence of two sets of backhaul link configurations, thus preventing configuration conflicts and reducing signaling overhead. Furthermore, the second configuration information is the backhaul link configuration information allocated to the relay node by the first host node after the relay node is reauthorized. This information ensures that the backhaul link configuration is based on the latest resource status, thereby improving resource allocation performance.

[0041] In another possible implementation of the first aspect, the second configuration information includes an IP address.

[0042] It should be noted that, in the embodiments of this application, "the second configuration information includes an IP address" generally means that the second configuration information includes one and only one IP address. In other words, when a relay node switches from an unauthorized state to an authorized state, the configuration information received by the relay node includes one and only one IP address. That is, the second configuration information may also include the default BAP configuration or BAP address, but it includes one and only one IP address, not multiple IP addresses.

[0043] This application provides a specific implementation of the second configuration information. Specifically, in a scenario where a relay node switches from an unauthorized state to an authorized state, the relay node receives second configuration information from the first host node to construct a backhaul link and conduct communication. The second configuration information includes only one IP address, not multiple IP addresses. It is understood that constructing a backhaul link requires one or more IP addresses; however, the IP address resources that a host node can allocate are limited. Allocating a single IP address to the relay node satisfies the requirement for constructing the backhaul link. If the relay node needs more IP addresses, it requests more IP addresses from the first host node.

[0044] Optionally, one of the IP addresses in the second configuration information mentioned above can be carried in an RRC message, such as an RRCReconfiguration message.

[0045] Optionally, one of the IP addresses in the second configuration information above can be used for the control plane protocol (F1-C). This F1-C can manage the interface between the relay node and the first host node, manage the relay node's DU, and execute UE context-related configurations.

[0046] In this embodiment of the application, the second configuration information includes only one IP address, which can save IP address resources and make full use of the limited IP address resources in the first host node.

[0047] In another possible implementation of the first aspect, the relay node sends a second message to the first host node, the second message being used to request at least one IP address.

[0048] In this embodiment of the application, the second information is used to request at least one IP address, and correspondingly, the first host node will allocate at least one IP address to the relay node according to the second information.

[0049] The implementation of this application does not limit the use of the aforementioned IP addresses. For example, they can be used for F1-C or User Plane Protocol F1-U, etc.

[0050] Optionally, the second information can be carried in an RRC message, such as IABOtherInformation.

[0051] Optionally, if the relay node requires more IP addresses, a second message is sent to the first host node. This application does not limit why the relay node needs more IP addresses, or the purpose of the IP addresses. For example, a relay node may need more IP addresses when it needs to transmit more traffic back.

[0052] This application provides a specific implementation method for the second information. Specifically, in scenarios where a relay node requires more IP addresses, the relay node sends the second information to the first host node. It is understood that the first host node will allocate at least one IP address to the relay node based on the second information, enabling the relay node to perform / complete the corresponding task. This method of allocating IP addresses to relay nodes according to their needs avoids allocating unused IP addresses, thereby saving IP address resources and improving IP address utilization.

[0053] In yet another possible implementation of the first aspect, the second configuration information does not include an IP address; the method further includes:

[0054] When the second triggering condition is met, the relay node sends third information to the first host node, the third information being used to request an IP address;

[0055] The second triggering condition includes at least one of the following:

[0056] The second configuration information includes a default BAP configuration; or, the second configuration information includes a BAP address; or, the relay node receives fourth information, which is used to indicate that the relay node is in an authorized state.

[0057] The second triggering condition in the embodiments of this application includes, but is not limited to, one or more of the following: the second configuration information includes a default BAP configuration; or, the second configuration information includes a BAP address; or, the relay node receives fourth information, which is used to indicate that the relay node is in an authorized state.

[0058] In this context, "relay node receiving the fourth message" typically refers to the relay node receiving the fourth message from the AMF (Advanced Management Function). In response, the AMF sends the fourth message back to the relay node. Generally, the AMF sends the fourth message to the relay node's NAS (Navigation Attached Function) layer, or the NAS layer sends the fourth message to the AS (Agency Attached Function) layer. That is, "relay node receiving the fourth message from the AMF" can be understood as the relay node receiving the fourth message from the AMF through the NAS layer, or, after receiving authorization information from the AMF at the NAS layer, the relay node receiving the fourth message from the NAS layer through the AS layer.

[0059] Optionally, the fourth information mentioned above is used to indicate that the relay node is in an authorized state. For example, the fourth information may indicate that the IAB Authorized value is equal to authorized, and the fourth information may also indicate that the mIAB Authorized value is equal to authorized. This application embodiment does not limit this.

[0060] In this embodiment of the application, when the second triggering condition is met, the relay node sends third information to the first host node. Correspondingly, the first host node also receives the third information from the relay node and sends one or more IP addresses to the relay node according to the third information.

[0061] Among them, at least one IP address used for F1-C is included in the IP address requested through the aforementioned third information request.

[0062] Optionally, the IP address in the third information request may also include the IP address used for F1-U.

[0063] This application provides a possible implementation of third information. Specifically, in scenarios where a second triggering condition is met, or where a relay node requires an IP address, the relay node sends third information to the first host node to request an IP address. It is understood that in this application's implementation, when the first host node sends backhaul link configuration to the relay node, it does not automatically assign an IP address to the relay node. Only when the second triggering condition is met will the relay node send third information to the first host node and request one or more IP addresses.

[0064] In another possible implementation of the first aspect, the fourth information comes from the non-access stratum NAS or access stratum AS of the relay node.

[0065] In this application, a possible specific implementation of the fourth information is provided. Specifically, the fourth information comes from the NAS layer or AS layer of the relay node. It is understood that the AMF is responsible for authenticating the authorization status of the relay node. After authentication, the AMF sends the authentication result to the relay node. For example, the AMF sends authorization status indication information to the NAS layer of the relay node to indicate the authorization status of the relay node. As another example, the NAS layer of the relay node sends indication information to the AS layer to indicate the authorization status of the relay node.

[0066] Optionally, the indication information sent by the AMF to the NAS layer can be carried in the NAS message.

[0067] Secondly, embodiments of this application provide a communication method, which can be executed by a communication device. The communication device can be a device, or a chip (system) or circuit used in a device; this application does not limit its scope. The method is applied to a first host node and includes:

[0068] When the relay node meets the third triggering condition, the first host node sends second configuration information to the relay node. The second configuration information is used to indicate the configuration of the backhaul link between the relay node and the first host node. The second configuration information includes an IP address.

[0069] The third triggering condition includes:

[0070] The relay node performs mobile terminal (MT) migration; and the relay node switches to authorized status.

[0071] Thirdly, embodiments of this application provide a communication method, which can be executed by a communication device. The communication device can be a device, or a chip (system) or circuit used in a device; this application does not limit its scope. The method is applied to a first host node and includes:

[0072] When the relay node meets the third triggering condition, the first host node sends second configuration information to the relay node. The second configuration information is used to indicate the configuration of the backhaul link between the relay node and the first host node. The second configuration information does not include the IP address.

[0073] The third triggering condition includes:

[0074] The relay node performs mobile terminal (MT) migration; and the relay node switches to authorized status.

[0075] Fourthly, embodiments of this application provide a communication method, which can be executed by a communication device. The communication device can be a machine, or a chip (system) or circuit used in a machine; this application does not limit its scope. The method is applied to a relay node and includes:

[0076] When the fourth triggering condition is met, the relay node saves the third configuration information of the backhaul link; the backhaul link is the backhaul link between the relay node and the first host node.

[0077] The fourth triggering condition includes:

[0078] The relay node performs MT migration; and, the relay node is in an unauthorized state; and, the relay node receives the third configuration information from the first host node, the third configuration information being used to indicate the configuration information of the backhaul link.

[0079] This application provides a communication method in which, under a fourth triggering condition, a relay node can save the configuration information of a backhaul link, which is the backhaul link between the relay node and the first host node. The fourth triggering condition includes the relay node being in an unauthorized state. This allows the relay node to directly activate the saved backhaul link configuration when it is switched to an authorized state, without needing to request the configuration again from the relay node, thus facilitating rapid startup after the relay node changes from unauthorized to authorized.

[0080] The relevant descriptions of the relay node, the first host node, and the second host node in the embodiments of this application can be found in the description of the first aspect above, and will not be repeated here.

[0081] In this application embodiment, the configuration information for saving the backhaul link can be stored, for example, in the memory of the relay node, or in other devices that allow the relay node to quickly obtain the configuration information. This application embodiment does not limit this to any particular method.

[0082] The fourth triggering condition in this application embodiment includes, but is not limited to:

[0083] The relay node performs MT migration. The relay node is in an unauthorized state. The relay node receives third configuration information from the first host node, which indicates the configuration of the backhaul link.

[0084] In this context, relay node performing MT migration can refer to the process after the first host node receives information instructing MT migration, for example, after the first host node receives MT migration instruction information from the second host node (e.g., a HANDOVER REQUEST message).

[0085] The term "unauthorized state" for a relay node can refer to the relay node being unauthorized under the second host node, the relay node being unauthorized under the first host node, or the relay node being only allowed to be in an unauthorized state under the current circumstances (e.g., a specific time period or a specific space). This application does not impose any restrictions on this.

[0086] A relay node being in an unauthorized state can also be understood as the relay node being about to be determined to be in an unauthorized state, or the relay node being indicated to be in an unauthorized state by other indication information, etc.

[0087] For example, the handover request message sent by the second host node to the first host node includes information indicating that the relay node is in an unauthorized state.

[0088] For example, the AMF sends a message to the first host node indicating that the relay node is in an unauthorized state. Specifically, the AMF sends a PATH SWITCH REQUEST ACK message to the first host node, carrying the relay node's authorization information indicating that the relay node is in an unauthorized state.

[0089] For example, the AMF directly sends information to the MT of the relay node indicating that the relay node is in an unauthorized state. Specifically, the AMF sends a NAS message to the MT of the relay node. This NAS message carries information about the authorized state of the MT of the relay node, and this authorized state information indicates that the MT of the relay node is in an unauthorized state.

[0090] The third configuration information is used to indicate the configuration of the backhaul link, which is a backhaul link between the relay node and the first host node. The configuration of the backhaul link is used to build the backhaul link for communication.

[0091] In an IAB network, during the MT migration of an IAB node, the second host node may send an indication of the relay node's authorized status to the first host node. This indication could be carried in a HANDOVER REQUEST message. Understandably, the authorized status indicated by this message typically refers to the relay node's authorized status under the second host node. For example, if the relay node is authorized under the second host node, the indication indicates that the relay node is authorized. Conversely, if the relay node is unauthorized under the second host node, the indication indicates that the relay node is unauthorized. If the first host node receives a message indicating that the relay node is unauthorized, it may not send backhaul link configuration information to the relay node. However, whether the relay node ultimately becomes authorized depends on the indication from the AMF (Automatic Handoff Authentication) system. If, after AMF authentication, the relay node becomes authorized, and the first host node then sends backhaul link configuration information to the relay node, it will affect the relay node's startup speed.

[0092] However, in this application's implementation, the triggering conditions for saving the backhaul link configuration are explicitly given. This ensures that when the fourth triggering condition is met, the relay node will save the backhaul link configuration and use it for rapid startup after relay node authorization. Furthermore, since the backhaul link configuration already saved in this application's implementation is used for rapid startup after relay node authorization, there is no need to send the backhaul link configuration information to the relay node again when the relay node switches to authorized status. This reduces signaling overhead during MT migration and also avoids conflicts in the backhaul link configuration.

[0093] In one possible implementation, the third configuration information of the backhaul link is still preserved under the following conditions: the relay node performs MT migration; the relay node is in an authorized state; and the relay node receives the third configuration information from the first host node, the third configuration information being used to indicate the configuration information of the backhaul link.

[0094] In one possible implementation of the fourth aspect, the method further includes:

[0095] The relay node receives fifth information, which indicates that the relay node is in an authorized state; the relay node performs backhaul link transmission based on the configuration information, and the backhaul link transmission includes establishing the relay node's F1 interface.

[0096] This application provides a possible specific implementation of the fifth information, specifically, the fifth information is used to indicate that the relay node is in an authorized state, and the fifth information may come from the AMF. For example, the AMF sends the fifth information to the relay node via a NAS message, or, after the AMF sends authorization information to the relay node via a NAS message, the NAS layer of the relay node then sends the fifth information to the AS layer. It is understood that after the relay node transitions from an unauthorized state to an authorized state, the relay node performs backhaul link transmission based on the aforementioned configuration information, allowing the relay node to start up quickly and avoiding backhaul link configuration conflicts.

[0097] The backhaul link transmission includes establishing the F1 interface of the relay node. For example, using the backhaul link constructed with the above configuration information, the relay node sends an F1 application protocol (F1AP) message to the F1 anchor CU of the relay node. Specifically, an F1 interface message can be sent to the F1 anchor CU through the backhaul link constructed above to request the establishment of the relay node's F1 interface.

[0098] Fifthly, embodiments of this application provide a communication method, which can be executed by a communication device. This communication device can be a device, or a chip (system) or circuit used in the device; this application does not limit its scope. The method is applied to a first host node and includes:

[0099] If the fourth condition is met, the first host node retains the configuration information of the backhaul link; the backhaul link is the backhaul link between the relay node and the first host node.

[0100] The fourth condition includes:

[0101] The first host node receives a sixth message from the Access and Mobility Management Function (AMF) element, the sixth message indicating that the relay node is in an unlicensed state; and the relay node is connected to the first host node.

[0102] This application provides a possible specific implementation of configuration information. Specifically, the first host node retains the aforementioned configuration information when a fourth condition is met. The fourth information includes a seventh information from the AMF indicating that the relay node is in an unauthorized state. This ensures that when the relay node is in an unauthorized state, the first host node ignores the AMF's indication and still retains the backhaul link configuration. This facilitates the direct use of the backhaul link configuration when the relay node switches to an authorized state, achieving rapid relay node activation. Furthermore, since the first host node retains this configuration information, it also ensures that when the relay node switches to an authorized state, the first host node will not send the backhaul link configuration to the relay node again, avoiding conflicts in the backhaul link configuration.

[0103] The descriptions of the relay node, first host node, and second host node in the embodiments of this application can be found in the relevant descriptions of the first aspect above, and will not be repeated here.

[0104] The sixth piece of information indicates that the relay node is in an unauthorized state. This sixth piece of information can be carried in the UE CONTEXT MODIFICATION REQUEST message. Alternatively, it can be carried in a NAS message sent to the relay node, which carries the relay node's authorized state as "authorized".

[0105] The connection between the relay node and the first host node mentioned above usually means that the relay node and the first host node are not disconnected. Specifically, it means that the MT of the relay node is connected to the first host node. For example, the backhaul link between the MT of the relay node and the first host node is not disconnected, or the MT of the relay node has not performed a new MT migration, etc.

[0106] In one possible implementation, the first host node retains the configuration information if the following conditions are met: the first host node receives indication information from the AMF indicating that the relay node is in an authorized state; and the relay node is connected to the first host node.

[0107] In an IAB network, during the MT migration of an IAB node, the second host node may send an indication of the relay node's authorized status to the first host node. This indication could be carried in a HANDOVER REQUEST message. Understandably, the authorized status indicated by this message typically refers to the relay node's authorized status under the second host node. For example, if the relay node is authorized under the second host node, the indication indicates that the relay node is authorized. Conversely, if the relay node is unauthorized under the second host node, the indication indicates that the relay node is unauthorized. If the first host node receives a message indicating that the relay node is unauthorized, it may not send backhaul link configuration information to the relay node. However, whether the relay node ultimately becomes authorized depends on the indication from the AMF (Automatic Handoff Authentication) system. If, after AMF authentication, the relay node becomes authorized, and the first host node then sends backhaul link configuration information to the relay node, it will affect the relay node's startup speed.

[0108] This application embodiment explicitly provides a method for the first host node to handle situations where the AMF indicates the relay node is in an unauthorized state. Specifically, the first host node ignores the AMF's indication information, that is, it does not consider whether the AMF's indication information indicates the relay node is in an authorized state, and directly sends the backhaul link configuration information to the relay node. This ensures that if the AMF's authentication result indicates the relay node is in an authorized state, the relay node directly uses the backhaul link configuration information. On the one hand, this achieves the effect of quickly enabling the relay node; on the other hand, it avoids the need for the first host node to resend the backhaul link configuration information to the relay node when the relay node switches to an authorized state, thus avoiding conflicts in the backhaul link configuration.

[0109] In one possible implementation of the fifth aspect, the method further includes:

[0110] The first host node receives the seventh information from the second host node and sends the backhaul link configuration information to the relay node;

[0111] The seventh piece of information is used to indicate that the relay node is in an unauthorized state.

[0112] This application provides a communication method in which a first host node receives seventh information from a second host node and sends backhaul link configuration information to a relay node. The seventh information indicates that the relay node is in an unauthorized state. By ignoring the authorization indication information from the second host node, the first host node enables the relay node to construct a backhaul link based on the configuration information even if the AMF authentication result is authorized, thus achieving rapid activation of the relay node.

[0113] Understandably, the first host node receives the seventh message from the second host node, and correspondingly, the second host node generates / sends the seventh message. The first host node sends the configuration information for the backhaul link, and correspondingly, the second host node also receives the configuration information for the backhaul link.

[0114] It should be noted that the first host node receiving the seventh message should not be interpreted as a condition triggering the first host node to send backhaul link configuration to the relay node. Rather, it should be understood that the first host node can send backhaul link configuration information to the relay node upon receiving the sixth message.

[0115] Optionally, the seventh piece of information can be carried in the relay node's MT migration request message, such as the HANDOVER REQUEST message.

[0116] Optionally, the configuration information for the backhaul link can be carried in a radio resource control (RRC) message, such as an RRCReconfiguration message.

[0117] Optionally, the configuration information for the backhaul link may include one or more of the following: default BAP configuration, BAP address, and IP address.

[0118] Optionally, the above IP address can be used at least for F1-C.

[0119] This application embodiment explicitly provides a method for the first host node to handle situations where the second host node indicates that the relay node is in an unauthorized state. Specifically, the first host node ignores the indication information from the second host node, that is, it does not consider whether the indication information from the second host node indicates that the relay node is in an authorized state, and directly sends the backhaul link configuration information to the relay node. This ensures that if the AMF authentication result is that the relay node is in an authorized state, the relay node directly uses the backhaul link configuration information. On the one hand, this achieves the effect of quickly enabling the relay node; on the other hand, it avoids the need for the first host node to send the backhaul link configuration information to the relay node again when the relay node switches to an authorized state, thus avoiding conflicts in the backhaul link configuration.

[0120] In one possible implementation, the first host node receives an indication from the second host node indicating that the relay node is in an authorized state, and still sends backhaul link configuration information to the relay node.

[0121] In one possible implementation of the fifth aspect, the method further includes:

[0122] If the relay node disconnects from the first host node, the configuration information is deleted.

[0123] This application provides a possible specific implementation for deleting backhaul link configuration information. Specifically, when the relay node disconnects from the first host node, the backhaul link configuration information of the first host node is deleted. This allows unused backhaul link configurations to be released in a timely manner, and if possible, these backhaul link configurations can be used by other nodes, thereby improving resource utilization.

[0124] It is understandable that the relay receiving node disconnecting from the first host node could mean that the relay node's MT (Metal Transporter) is disconnected from the first host node, or that the backhaul link between the relay node's MT and the first host node is broken, or that the relay node's MT has undergone MT migration, etc.

[0125] The aforementioned deletion of configuration information on the first host node could mean either releasing the configuration information or adjusting the configuration information to be usable by other nodes.

[0126] In a sixth aspect, embodiments of this application provide a communication device that includes a unit for performing the method as described in any of the first aspects.

[0127] In one possible design, the device includes:

[0128] The processing unit is used to release the configuration of the backhaul link when the relay node meets the first triggering condition; the backhaul link is the backhaul link between the relay node and the first host node.

[0129] The first triggering condition includes:

[0130] The relay node performs mobile terminal (MT) migration; and, the relay node is in an unauthorized state; and, the relay node receives first configuration information from the first host node, the first configuration information being used to indicate the configuration of the backhaul link.

[0131] In one possible implementation, the device further includes:

[0132] The communication unit is configured to receive second configuration information from the first host node when the relay node switches to an authorized state, the second configuration information being used to indicate the configuration of the backhaul link.

[0133] In one possible implementation, the communication unit is further configured to send second information, which requests at least one IP address.

[0134] In one possible implementation, the communication unit is also used to send third information, which is used to request an IP address.

[0135] The methods executed by the aforementioned processing unit and communication unit can be found in the methods corresponding to the first aspect above, and will not be repeated here.

[0136] For the technical effects of the sixth aspect and any possible implementation, please refer to the description of the technical effects corresponding to the first aspect and the corresponding implementation.

[0137] In a seventh aspect, embodiments of this application provide a communication device that includes a unit for performing the method as described in any of the second aspects.

[0138] In one possible design, the device includes:

[0139] A communication unit is used to send second configuration information from the first host node to the relay node when the relay node meets a third triggering condition. The second configuration information is used to indicate the configuration of the backhaul link between the relay node and the first host node. The second configuration information includes an IP address.

[0140] The third triggering condition includes:

[0141] The relay node performs mobile terminal (MT) migration; and the relay node switches to authorized status.

[0142] In one possible design, the device also includes:

[0143] The processing unit is used to generate the aforementioned second configuration information.

[0144] The methods executed by the aforementioned processing unit and communication unit can be found in the corresponding methods of the second aspect above, and will not be repeated here.

[0145] For the technical effects of the seventh aspect and any possible implementation, please refer to the description of the technical effects corresponding to the second aspect and the corresponding implementation.

[0146] Eighthly, embodiments of this application provide a communication device including a unit for performing the method as described in any of the third aspects.

[0147] In one possible design, the device includes:

[0148] A communication unit is used so that, when a third triggering condition is met, the first host node sends second configuration information to the relay node. The second configuration information is used to indicate the configuration of the backhaul link between the relay node and the first host node; the second configuration information does not include an IP address.

[0149] The third triggering condition includes:

[0150] The relay node performs mobile terminal (MT) migration; and the relay node switches to authorized status.

[0151] In one possible design, the device also includes:

[0152] The processing unit is used to generate the aforementioned second configuration information.

[0153] The methods executed by the aforementioned processing unit and communication unit can be found in the method corresponding to the third aspect above, and will not be repeated here.

[0154] For the technical effects of the eighth aspect and any possible implementation, please refer to the description of the technical effects corresponding to the third aspect and the corresponding implementation.

[0155] Ninthly, embodiments of this application provide a communication device including a unit for performing the method as described in any of the fourth aspects.

[0156] In one possible design, the device includes:

[0157] The processing unit is used to save the third configuration information of the backhaul link when the relay node meets the fourth triggering condition; the backhaul link is the backhaul link between the relay node and the first host node.

[0158] The fourth triggering condition includes:

[0159] The relay node performs MT migration; and, the relay node is in an unauthorized state; and, the relay node receives the third configuration information from the first host node, the third configuration information being used to indicate the configuration information of the backhaul link.

[0160] In one possible design, the device also includes:

[0161] The communication unit is used to receive the aforementioned third configuration information.

[0162] The methods executed by the aforementioned processing unit and communication unit can be found in the corresponding method in the fourth aspect above, and will not be repeated here.

[0163] For the technical effects of the ninth aspect and any possible implementation, please refer to the description of the technical effects corresponding to the fourth aspect and the corresponding implementation.

[0164] In a tenth aspect, embodiments of this application provide a communication device including a unit for performing the method as described in any of the fifth aspects.

[0165] In one possible design, the device includes:

[0166] The processing unit is configured to retain the configuration information of the backhaul link when the first host node meets the fourth condition; the backhaul link is the backhaul link between the relay node and the first host node.

[0167] The fourth condition includes:

[0168] The first host node receives a sixth message from the Access and Mobility Management Function (AMF) element, the sixth message indicating that the relay node is in an unlicensed state; and the relay node is connected to the first host node.

[0169] In one possible design, the device also includes:

[0170] The communication unit is used to receive the seventh information from the second host node and send the configuration information of the backhaul link to the relay node;

[0171] The seventh piece of information is used to indicate that the relay node is in an unauthorized state.

[0172] The methods executed by the aforementioned processing unit and communication unit can be found in the corresponding method in the fifth aspect above, and will not be repeated here.

[0173] For the technical effects of the tenth aspect and any possible implementation, please refer to the description of the technical effects corresponding to the fifth aspect and the corresponding implementation.

[0174] Optionally, in the communication apparatus described in any of the sixth to tenth aspects and any of the possible embodiments:

[0175] In one implementation, the communication device is a communication equipment. When the communication device is a communication equipment, the communication unit can be a transceiver or an input / output interface; the processing unit can be at least one processor. Optionally, the transceiver can be a transceiver circuit. Optionally, the input / output interface can be an input / output circuit.

[0176] In another implementation, the communication device is a chip (system) or circuit used in a communication device. When the communication device is a chip (system) or circuit used in a communication device, the communication unit can be a communication interface (input / output interface), interface circuit, output circuit, input circuit, pin, or related circuit on the chip (system) or circuit; the processing unit can be at least one processor, processing circuit, or logic circuit.

[0177] Eleventhly, embodiments of this application provide a communication device including a processor. The processor is coupled to a memory and can be used to execute instructions in the memory to implement the methods of any one of the first to fifth aspects and any possible implementations described above. Optionally, the communication device further includes a memory. Optionally, the communication device further includes a communication interface, and the processor is coupled to the communication interface.

[0178] In a twelfth aspect, embodiments of this application provide a communication device, including: a logic circuit and a communication interface. The communication interface is used to receive or send information; the logic circuit is used to receive or send information through the communication interface, causing the communication device to perform the method of any one of the first to fifth aspects and any possible implementation thereof.

[0179] In a thirteenth aspect, embodiments of this application provide a computer-readable storage medium for storing a computer program (also referred to as code or instructions); when the computer program is run on a computer, the methods of any of the first to fifth aspects and any possible implementations described above are implemented.

[0180] In a fourteenth aspect, embodiments of this application provide a computer program product comprising: a computer program (also referred to as code or instructions); and, when the computer program is run, causing a computer to perform the method described in any of the first to fifth aspects and any possible implementation thereof.

[0181] In a fifteenth aspect, embodiments of this application provide a chip including a processor configured to execute instructions, which, when executed, cause the chip to perform the methods described in any one of the first to fifth aspects and any possible implementation thereof. Optionally, the chip further includes a communication interface configured to receive or transmit signals.

[0182] In a sixteenth aspect, embodiments of this application provide a communication system, the communication system including at least one communication device as described in the sixth to tenth aspects, or the communication device as described in the eleventh aspect, or the communication device as described in the twelfth aspect, or the chip as described in the fifteenth aspect.

[0183] In a seventeenth aspect, embodiments of this application provide a communication system, the communication system including at least one of a relay node and a first host node, wherein the relay node is used to perform the methods of the first aspect or the fourth aspect and any possible implementation thereof, and the second host node is used to perform the methods of the second aspect or the third aspect or the fifth aspect and any possible implementation thereof.

[0184] Furthermore, in the process of performing the methods described in any of the first to fifth aspects and any possible embodiments described above, the processes related to sending and / or receiving information in the above methods can be understood as the process of the processor outputting information, and / or the process of the processor receiving input information. When outputting information, the processor can output the information to a transceiver (or communication interface, or transmitting module) so that the transceiver can transmit it. After the information is output by the processor, it may need to undergo other processing before reaching the transceiver. Similarly, when the processor receives input information, the transceiver (or communication interface, or transmitting module) receives the information and inputs it to the processor. Furthermore, after the transceiver receives the information, the information may need to undergo other processing before being input to the processor.

[0185] Based on the above principles, for example, the information sent mentioned in the aforementioned method can be understood as information output by the processor. Similarly, the information received can be understood as information received by the processor from input.

[0186] Optionally, unless otherwise specified, or unless they contradict their actual function or internal logic in the relevant description, the operations of the processor, such as transmitting, sending, and receiving, can be more generally understood as processor output and receiving, input, and other operations.

[0187] Optionally, in the process of performing the methods described in any of the first to fifth aspects and any possible embodiments, the processor may be a processor specifically designed to perform these methods, or it may be a processor that performs these methods by executing computer instructions stored in memory, such as a general-purpose processor. The memory may be a non-transitory memory, such as read-only memory (ROM), which may be integrated with the processor on the same chip or disposed on different chips. This application does not limit the type of memory or the arrangement of the memory and processor.

[0188] In one possible implementation, at least one of the aforementioned memories is located outside the device.

[0189] In yet another possible implementation, at least one of the aforementioned memories is located within the device.

[0190] In another possible implementation, a portion of the memory of the at least one memory is located inside the device, while another portion is located outside the device.

[0191] In this application, the processor and memory may also be integrated into a single device, that is, the processor and memory can be integrated together.

[0192] In this application's implementation, the triggering conditions for releasing backhaul link configurations are explicitly provided. This ensures that, upon meeting the first triggering condition, relay nodes will promptly release backhaul link configurations, allowing temporarily unused backhaul link configurations to be released and potentially used by other nodes, thus improving resource utilization. Furthermore, it avoids assigning two sets of backhaul link configurations to IAB nodes, thereby preventing backhaul link configuration conflicts and reducing signaling overhead during MT migration. Attached Figure Description

[0193] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0194] Figure 1 is a schematic diagram of the structure of an IAB system provided in an embodiment of this application;

[0195] Figure 2 is a schematic diagram of the structure of an IAB node provided in an embodiment of this application;

[0196] Figure 3 is a schematic diagram of the structure of an IAB network provided in an embodiment of this application;

[0197] Figure 4 is a schematic diagram of a control plane protocol architecture in an IAB network provided in an embodiment of this application;

[0198] Figure 5 is a schematic diagram of a user plane protocol architecture in an IAB network provided in an embodiment of this application;

[0199] Figure 6 is an example of an IAB network architecture diagram provided in an embodiment of this application;

[0200] Figure 7 is an example of a BAP topology of an IAB network provided in an embodiment of this application;

[0201] Figure 8 is a schematic diagram of an IAB node joining the network according to an embodiment of this application;

[0202] Figure 9 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0203] Figure 10 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0204] Figure 11 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0205] Figure 12 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0206] Figure 13 is a flowchart illustrating another communication method provided in an embodiment of this application;

[0207] Figure 14 is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0208] Figure 15 is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0209] Figure 16 is a schematic diagram of the structure of a chip provided in an embodiment of this application. Detailed Implementation

[0210] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described below with reference to the accompanying drawings.

[0211] The terms "first" and "second," etc., used in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0212] The term "embodiment" as used herein means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that, unless otherwise specified or logically conflicting, the terminology and / or descriptions between the various embodiments of this application are consistent and can be mutually referenced, and technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0213] It should be understood that in this application, "at least one (item)" means one or more, "more than one" means two or more, "at least two (items)" means two or three or more, and "and / or" is used to describe the relationship between related objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0214] It should be noted that, in this application, "instruction" can include direct instruction, indirect instruction, explicit instruction, and implicit instruction. When describing a certain instruction information for the purpose of instructing A, it can be understood that the instruction information carries A, directly instructs A, or indirectly instructs A.

[0215] In this application, the information indicated by the instruction information is called the information to be instructed. In specific implementations, there are many ways to indicate the information to be instructed, such as, but not limited to, directly indicating the information to be instructed, such as the information to be instructed itself or its index. It can also indirectly indicate the information to be instructed by indicating other information, where there is a correlation between the other information and the information to be instructed. It can also indicate only a part of the information to be instructed, while the other parts are known or pre-agreed upon. For example, the instruction of specific information can be achieved by using a pre-agreed (e.g., protocol-defined) arrangement of various information, thereby reducing instruction overhead to some extent. The information to be instructed can be sent as a whole or divided into multiple sub-information units, and the sending period and / or timing of these sub-information units can be the same or different. This application does not limit the specific sending method. The sending period and / or timing of these sub-information units can be predefined, for example, according to a protocol, or configured by the transmitting device by sending configuration information to the receiving device.

[0216] It should be noted that in this application, "send" can be understood as "output" and "receive" can be understood as "input". "Send information to A", where "to A" simply indicates the direction of information transmission, and A is the destination, does not limit "send information to A" to a direct transmission over the air interface. "Send information to A" includes sending information directly to A, as well as sending information indirectly to A through a transmitter. Therefore, "send information to A" can also be understood as "outputting information destined for A". Similarly, "receive information from A" indicates that the source of the information is A, including receiving information directly from A, as well as receiving information indirectly from A through a receiver. Therefore, "receive information from A" can also be understood as "inputting information from A".

[0217] Before introducing this application, some terms used in the embodiments of this application will be briefly explained to facilitate understanding by those skilled in the art.

[0218] 1) A terminal-side device is a device that provides voice and / or data connectivity to a user. In the embodiments of this application, a terminal-side device may be referred to as user equipment (UE), terminal equipment, terminal, mobile station (MS), mobile terminal (MT), etc. For example, a terminal-side device may include a handheld device with wireless connectivity or a communication device connected to a wireless modem. The terminal-side device can communicate with the core network via a radio access network (RAN) and exchange voice and / or data with the RAN.

[0219] Examples of terminal-side devices include: mobile stations (MS), subscriber units, cellular phones, smartphones, wireless data cards, personal digital assistants (PDAs), computers, tablets, modems, handsets, laptop computers, machine-type communication (MTC) terminals, wearable devices, and in-vehicle terminal equipment. Terminal-side devices also include limited devices, such as those with low power consumption, limited storage capacity, or limited computing power. Terminal-side devices also include information sensing devices such as barcode scanners, radio frequency identification (RFID), sensors, global positioning systems (GPS), and laser scanners.

[0220] The functions of the terminal-side device can be implemented through internal hardware components, which can be a processor and / or a programmable chip within the terminal device. Optionally, the chip can be implemented using an application-specific integrated circuit (ASIC) or a programmable logic device (PLD). The PLD can be any one of the following, or any combination thereof: a complex programmable logical device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or a system-on-a-chip (SOC).

[0221] 2) The host base station (donor gNodeB), also known as the host node, connects to the core network. In other words, the host base station is the device in the communication system that connects terminal-side devices to the core network. Host base stations are typically connected to the core network via a wired link (e.g., fiber optic cable). The host base station is responsible for receiving data from the core network and forwarding it to wireless backhaul equipment (e.g., IAB nodes), or receiving data from wireless backhaul equipment and forwarding it to the core network. Host base stations are generally connected to the network via a wired connection.

[0222] As an example, the host base station may include a radio network controller (RNC), a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., a home evolved Node B, or a home Node B, HNB), a base band unit (BBU), etc., or it may include an evolved Node B (Node B, eNB, or e-Node B) in an evolved LTE system (LTE-Advanced, LTE-A), or it may include a next-generation Node B (gNB) in a fifth-generation (5G) new radio (NR) system. As another example, the host base station may include a centralized unit (CU) (hereinafter referred to as Donor-CU or gNB-CU) and a distributed unit (DU) (hereinafter referred to as Donor-DU or gNB-DU). The gNB-CU and gNB-DU are connected via the F1 interface, which can further include a control plane interface (F1-C) and a user plane interface (F1-U). The Donor-CU and the core network are connected via a next-generation (NG) interface. The gNB-CU or Donor-CU can also exist in a separate form, with the user plane (UP) (hereinafter referred to as CU-UP) and control plane (CP) (hereinafter referred to as CU-CP), meaning the gNB-CU or Donor-CU consists of CU-CP and CU-UP. One gNB-CU can include one gNB-CU-CP and at least one gNB-CU-UP. Alternatively, one Donor-CU can include one Donor-CU-CP and at least one Donor-CU-UP.

[0223] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0224] The functionality of the host base station can be implemented by internal hardware components, such as the processor and / or programmable chip described above. For example, this chip can be implemented using an ASIC or a PLD. The PLD can be any one of a CPLD, FPGA, GAL, or SOC, or any combination thereof.

[0225] This application provides a communication method applicable to the field of communication technology, such as communication in IAB networks. To more clearly describe the solution of this application, some knowledge related to IAB will be introduced below.

[0226] In an IAB network, an IAB node can establish a wireless backhaul link with one or more upstream nodes and access the core network through these upstream nodes. Upstream nodes can control relay nodes through various signaling mechanisms (e.g., data scheduling, timing modulation, power control). Additionally, a relay node can establish an access link with one or more downstream nodes and provide access services to them. The upstream node of a relay node can be a base station or another relay node. The downstream node of a relay node can be a terminal or another relay node. In some cases, the upstream node of an IAB node can also be called its upstream node or parent node, and the downstream node of that IAB node can also be called its downstream node or child node.

[0227] Please refer to Figure 1, which is a schematic diagram of the structure of an IAB system provided in an embodiment of this application.

[0228] As shown in Figure 1, the IAB node provides radio access and radio backhaul for access services to the UE. The IAB host node (IAB donor node) provides radio backhaul functionality to the IAB node and provides an interface between the UE and the core network. The IAB node connects to the IAB donor node through the radio backhaul link, thereby enabling the UE served by the IAB node to connect to the core network.

[0229] Please refer to Figure 2, which is a schematic diagram of the structure of an IAB node provided in an embodiment of this application.

[0230] As shown in Figure 2, the IAB node in NR can be divided into two parts: MT and DU. MT can be understood as a component similar to a UE within the IAB node; MT is referred to as the function residing on the IAB node. Since MT functions similarly to a regular UE, it can be understood that MT is used for communication between the IAB node and its superior node. DU, in contrast to the CU function of network devices, is used for communication between the IAB node and its subordinate nodes. It should be understood that the superior node can be a base station or other IAB nodes, and the subordinate node can be a UE or other IAB nodes.

[0231] The communication method provided in this application can be applied to various communication systems that include relay nodes, such as NR systems, LTE systems, LTE-A systems, Worldwide Interoperability for Microwave Access (WiMAX), or Wireless Local Area Networks (WLAN). In LTE, a relay node is generally referred to as an RN. In NR, a relay node is generally referred to as an IAB node. In some embodiments, a relay node can also be referred to as a relay device or a relay transmission and reception point (rTRP), and the upstream node of the relay node can be a network device (including a DU of a network device, or a CU of a network device, etc.).

[0232] Please refer to Figure 3, which is a schematic diagram of the structure of an IAB network provided in an embodiment of this application.

[0233] As shown in Figure 3, the IAB network includes multiple UEs and multiple IAB nodes. Figure 3 uses an example with 2 UEs and 5 IAB nodes. The two UEs are UE1 and UE2, and the five IAB nodes are IAB nodes 1 through 5. It should be understood that the thick lines in Figure 3 represent access links, and the thin lines represent backhaul links. UE2 can connect to the host base station via IAB node 5, IAB node 2, and IAB node 1. UE2 can also connect to the host base station via IAB node 4, IAB node 2, and IAB node 1. Alternatively, UE2 can also connect to the host base station via IAB node 4, IAB node 3, and IAB node 1. UE1 can connect to the host base station via IAB node 4, IAB node 3, and IAB node 1. UE1 can also connect to the host base station via IAB node 4, IAB node 2, and IAB node 1.

[0234] It should be noted that the communication system shown in Figure 3 is merely an example and does not limit the application scenarios applicable to the embodiments of this application. It should be understood that the use of IAB nodes in the embodiments of this application is solely for descriptive purposes and does not imply that the solutions in the embodiments of this application are only applicable to NR scenarios. In the embodiments of this application, IAB nodes can refer to any node or device with relay functionality, and the use of IAB nodes and relay nodes in the implementation of this application should be understood to have the same meaning.

[0235] In an IAB network, IAB nodes connect to the core network via IAB host nodes. For example, in a standalone (SA) 5G architecture, IAB nodes connect to the 5G core network (5G core network, 5GC / 5GCN) via IAB host nodes. As another example, in dual connectivity (DC) or multi-connectivity (MC) 5G architectures (e.g., non-standalone, NSA scenarios), on the main path, IAB nodes can connect to the evolved packet core (EPC) via evolved NodeBs (eNBs) or to the 5G core network via an IAB host.

[0236] In an IAB network, a transmission path between a UE and an IAB host can contain one or more IAB nodes. Each IAB node needs to maintain a radio backhaul link to its parent node and also needs to maintain radio links with its child nodes. If the child node of an IAB node is a UE, there is a radio access link between the IAB node and its child node (i.e., the UE). If the child node of an IAB node is another IAB node, there is a radio backhaul link between the IAB node and its child node (i.e., the other IAB node). For example, referring to Figure 3, in the path "UE1→IAB node 4→IAB node 3→IAB node 1→IAB host", UE1 accesses IAB node 4 through the radio access link, IAB node 4 connects to IAB node 3 through the radio backhaul link, IAB node 3 connects to IAB node 1 through the radio backhaul link, and IAB node 1 connects to the IAB host node through the radio backhaul link.

[0237] In this embodiment, the access IAB node refers to the IAB node that the UE accesses, and the intermediate IAB node refers to the IAB node that provides wireless backhaul services to the UE or the IAB node. For example, referring to Figure 3, in the path "UE1→IAB node 4→IAB node 3→IAB node 1→IAB host", IAB node 4 is the access IAB node, and IAB node 3 and IAB node 1 are intermediate IAB nodes. It should be noted that an IAB node is an access IAB node for the UE accessing that IAB node; for UEs accessing other IAB nodes, it is an intermediate IAB node. Therefore, whether an IAB node is specifically an access IAB node or an intermediate IAB node is not fixed and can be determined according to the specific application scenario.

[0238] It should be noted that the communication system shown in Figure 3 is merely an example and does not limit the application scenarios applicable to the embodiments of this application. It should be understood that the use of IAB nodes in the embodiments of this application is solely for descriptive purposes and does not imply that the solutions in the embodiments of this application are only applicable to new radio (NR) scenarios.

[0239] There is an F1 interface between the DU of the IAB node and the CU of the IAB host. This F1 interface can consist of two parts: a control plane and a user plane. The user plane part is maintained between the IAB-DU and the IAB donor CU-UP, while the control plane part is maintained between the IAB-DU and the IAB donor CU-CP. This F1 interface can also be called an F1* interface; this embodiment does not limit the name of the interface. Furthermore, this document refers to it as the F1 interface.

[0240] The F1 interface supports user plane protocols (F1-U / F1*-U) and control plane protocols (F1-C / F1*-C). User plane protocols include one or more of the following protocol layers: General Packet Radio Service (GPRS) Tunneling Protocol User Plane (GTP-U) layer, User Datagram Protocol (UDP) layer, Internet Protocol (IP) layer, etc. Control plane protocols include one or more of the following protocol layers: F1 Application Protocol (F1AP), Stream Control Transport Protocol (SCTP), IP layer, etc. Through the control plane of the F1 / F1* interface, IAB nodes and IAB hosts can perform interface management, manage IAB-DUs, and perform UE context-related configurations. Through the user plane of the F1 / F1* interface, IAB nodes and IAB hosts can perform user plane data transmission and downlink transmission status feedback functions.

[0241] For example, please refer to Figures 4 and 5, where Figure 4 is a schematic diagram of a control plane protocol architecture in an IAB network provided in an embodiment of this application, and Figure 5 is a schematic diagram of a user plane protocol architecture in an IAB network provided in an embodiment of this application.

[0242] For the control plane, as shown in Figure 4, a Uu interface is established between UE1 and IAB2-DU, with corresponding protocol layers including the Radio Link Control (RLC) layer, Media Access Control (MAC) layer, and Physical Layer (PHY) layer. IAB2-DU and IAB donor CU1 establish an F1-C interface, with corresponding protocol layers including the F1AP layer and SCTP layer. IAB donor DU1 and IAB donor CU1 are connected via a wired connection, with corresponding protocol layers including the Internet Protocol (IP) layer, L2, and L1. BL connections are established between IAB node 2 and IAB node 3, between IAB node 3 and IAB node 1, and between IAB node 1 and IAB donor DU1, with corresponding protocol layers including the Backhaul Adaptation Protocol (BAP) layer, RLC layer, MAC layer, and PHY layer. In addition, a peer-to-peer radio resource control (RRC) layer and packet data convergence protocol (PDCP) layer are established between UE1 and IAB donor CU 1, and a peer-to-peer IP layer is established between IAB2-DU and IAB donor DU 1.

[0243] It can be seen that, compared with the control plane protocol stack of a single air interface, the DU accessing the IAB node in the IAB network implements the functions of a gNB-DU (i.e., establishing peer-to-peer RLC, MAC, and PHY layers with the UE, and establishing peer-to-peer F1AP and SCTP layers with the CU). In other words, the DU accessing the IAB node in the IAB network implements the functions of a gNB-DU (single air interface); the IAB donor CU implements the functions of a gNB-CU (single air interface).

[0244] On the control plane, RRC messages are encapsulated in F1AP messages between the access IAB node and the IAB donor CU for transmission. Specifically, in the uplink direction, UE1 encapsulates the RRC message in a PDCP protocol data unit (PDU) and sends it to IAB2-DU after processing by the RLC, MAC, and PHY layers. IAB2-DU is processed by the PHY, MAC, and RLC layers to obtain a PDCP PDU, which is then encapsulated in an F1AP message and processed by the SCTP and IP layers to obtain an IP packet. IAB2-MT sends the IP packet to IAB3-DU after processing by the BAP, RLC, MAC, and PHY layers. IAB3-DU is processed by the PHY, MAC, RLC, and BAP layers to obtain an IP packet, and then IAB3-MT sends the IP packet to IAB1-DU using a similar operation to IAB2-MT. Similarly, IAB1-MT sends the IP packet to IAB donor DU 1. After IAB donor DU 1 parses the IP packet, it sends the IP packet to IAB donor CU 1. IAB donor CU 1 processes the IP packet sequentially through the SCTP layer, F1AP layer, and PDCP layer to obtain the RRC message. The downlink direction is similar and will not be described further here.

[0245] For the user plane, as shown in Figure 5, a Uu interface is established between UE1 and IAB2-DU, with corresponding protocol layers including RLC, MAC, and PHY. An F1-U interface is established between IAB2-DU and IAB donor CU1, with corresponding protocol layers including GTP-U and User Datagram Protocol (UDP). IAB donor DU1 and IAB donor CU1 are connected via a wired connection, with corresponding protocol layers including IP, L2, and L1. BL connections are established between IAB node 2 and IAB node 3, between IAB node 3 and IAB node 1, and between IAB node 1 and IAB donor DU1, with corresponding protocol layers including BAP, RLC, MAC, and PHY. Additionally, corresponding SDAP and PDCP layers are established between UE1 and IAB donor CU1, and a corresponding IP layer is established between IAB2-DU and IAB donor DU1.

[0246] It can be seen that, compared with the user plane protocol stack of a single air interface, the user plane protocol stack of the IAB access node implements some of the functions of the gNB-DU of the single air interface (i.e., the functions of establishing peer-to-peer RLC, MAC, and PHY layers with the terminal, and the functions of establishing peer-to-peer GTP-U and UDP layers with the IAB donor CU 1). It can be understood that the DU of the IAB access node implements the functions of the gNB-DU of the single air interface; the IAB donor CU implements the functions of the gNB-CU of the single air interface.

[0247] On the user plane, PDCP packets are encapsulated in a GTP-U tunnel between the access IAB node and the IAB donor CU for transmission. The GTP-U tunnel is established on the F1-U interface.

[0248] The communication method provided in this application is mainly applied to IAB networks, including standalone (SA) IAB networks and non-standalone (NSA) IAB networks. An IAB node comprises an MT (Medium-Level) part and a DU (Digital-Level) part. The IAB donor can be further divided into DU and CU parts, and the CU can be further divided into CU-CP and CU-UP parts.

[0249] Please refer to Figure 6, which is an example of an IAB network architecture diagram provided in an embodiment of this application.

[0250] Figure 6 illustrates an example of an IAB node connecting to an IAB donor via a wireless backhaul link. Figure 6 uses an example comprising one UE, two IAB nodes, and two IAB donors. The two IAB nodes are IAB node 1 and IAB node 2, each including both an MT (Media Access Point) and a DU (Digital Access Point) portion. The two IAB donors are IAB donor 1 and IAB donor 2. Each IAB donor can be further divided into a DU and a CU portion, and the CU can be further divided into a CU-CP and a CU-UP portion. In Figure 6, communication between the MT of IAB Node 2 and the DU of IAB Node 1, between the MT of IAB Node 1 and the DU of IAB donor 1, and between the MT of IAB Node 1 and the DU of IAB donor 2 is conducted via wireless backhaul (BH) links; a Uu interface is established between the UE and the IAB2-DU; an F1-C interface is established between the IAB donor DU and the IAB donor CU-CP, and an F1-U interface is established between the IAB donor DU and the IAB donor CU-UP; the DU of IAB donor 2 and the CU of IAB donor 1 are connected via an Internet Protocol (IP) network.

[0251] When an IAB node operates in SA mode, it can connect to a single parent node or two parent nodes. These two parent nodes can be controlled by the same IAB donor or by different IAB donors. The DU portion of the IAB node establishes an F1 interface with one IAB donor, which can then connect to the 5G core network, as shown by the dashed line in Figure 6. Specifically, the IAB-donor-CU-CP connects to control plane network elements (e.g., access and mobility management functions) in the 5GC via the NG control plane interface (NG-C), and the IAB-donor-CU-UP connects to user plane network elements (e.g., user plane functions) in the 5GC via the NG user plane interface (NG-U).

[0252] When the IAB node is operating in NSA mode, the IAB-donor-CU-UP can connect to the EPC (e.g., to the service gateway, SGW) through the S1 user plane interface (S1-U). 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-donor-CU-CP. The MeNB connects to the EPC (including the S1 interface user plane and the S1 interface control plane) through the S1 interface, which is the dashed line part in Figure 6.

[0253] In another possible scenario, the MeNB in ​​Figure 6 can be replaced with a 5G base station gNB. The LTE-Uu interface in Figure 6 is replaced with the NR-Uu interface. The gNB can establish user plane and / or control plane interfaces with the 5GC. The gNB and IAB-donor provide dual connectivity services for the IAB node. The gNB can act as the primary base station or the secondary base station for the IAB node.

[0254] The foregoing is an example of an application scenario of the technical solution of the present application. It should be understood that the technical solution of the present application is not limited to the network architecture shown in Figure 6.

[0255] In an IAB network, IAB nodes are mobile, such as vehicle-mounted IAB nodes. For example, a mobile IAB node can be called a mobile IAB node (mIAB), as shown in Figure 7. During movement, a mIAB node can switch from IAB donor1 to IAB donor2. Because the coverage of donor CU1 is limited, it cannot maintain the F1 connection with the mIAB-DU indefinitely. Therefore, the F1 connection of the mIAB-DU needs to be migrated from Donor-CU1 to Donor-CU2. In this scenario, the way the mIAB-DU needs to migrate its RRC and F1 connections from Donor-CU1 to Donor-CU2 can be called a full migration.

[0256] For example, in an IAB network, to enhance network robustness and achieve more granular load balancing and topology management, mIAB nodes can undergo a partial migration process. This involves the miB node's MT (IAB-MT2 in Figure 7) switching from one parent node (IAB-node1 in Figure 7) to another parent node (IAB-node3 in Figure 7). The two parent nodes belong to different host CU-controlled topologies; IAB-node1 belongs to the topology controlled by Donor-CU1 (solid box in Figure 7), and IAB-node3 belongs to the topology controlled by Donor-CU2 (dashed box in Figure 7). During the partial migration, IAB-MT2's RRC connection switches from CU1 to CU2, but IAB-DU2's F1 connection still terminates at CU1 (as shown by the solid arrow in Figure 7) and does not migrate to CU2 along with IAB-MT2. It is understandable that the F1 connection of IAB node 4, a child node of IAB node 2, can also terminate at CU1 (as shown by the dashed arrow in Figure 7).

[0257] For example, if the F1 interface of IAB node 2 terminates at CU1, then IAB host 1 can be referred to as the F1-terminating IAB-donor of IAB node 2. If CU2 has an RRC connection with IAB node 2 but the F1 connection of IAB node 2 does not terminate at CU2, then IAB host 2 can be referred to as the non-F1-terminating IAB-donor of IAB node 2.

[0258] After IAB node 2 switches from the CU1 topology to the CU2 topology, in order to migrate the data traffic of IAB node 2 from the CU1 topology to the CU2 topology, the 3rd generation partnership project (3GPP) Release-17 standard (R17) introduced the IAB Transport Migration Management process. That is, CU1 can use the Xn interface between it and CU2 to perform the IAB Transport Migration Management process to migrate the data traffic of IAB node 2 to CU2. The specific details of the IAB Transport Migration Management process are as follows:

[0259] Step S701: CU1 sends an IAB Transport Migration Management request message to CU2, and CU2 receives the IAB Transport Migration Management request message accordingly.

[0260] Here, CU1 is the F1-terminating IAB-donor of IAB node 2, and CU2 is the non-F1-terminating IAB-donor of IAB node 2. The IAB transport migration management request message is used to request the migration of data traffic from IAB node 2 to CU2.

[0261] Step S702: CU2 sends an IAB Transport Migration Management response message to CU1, and CU1 receives the IAB Transport Migration Management response message accordingly.

[0262] The IAB transport migration management response message is used to respond to the aforementioned IAB transport migration management request message in order to migrate the data traffic of the IAB node 2 to the CU2.

[0263] Details of the aforementioned "IAB Transport Migration Management" process can be found in 3GPP protocol TS 38.423R17, but it is not limited to the methods described in that protocol. During this process, CUs (Continuous Units) exchange Quality of Service (QoS) information and corresponding Integrated Access and Backhaul (IAB) configuration information to offload data traffic. The R17 standard specifies that this process is initiated by the F1-terminating IAB-donor (CU1 in Figure 7) to the Non-F1-terminating IAB-donor (CU2 in Figure 7).

[0264] In an IAB network, the IAB integration process includes IAB-MT integration and IAB-DU integration. Since the IAB-DU integration process requires the use of the backhaul link established between the IAB-MT and the host node, IAB-DU integration must occur after the IAB-MT integration is completed.

[0265] Please refer to Figure 8, which is a schematic diagram of an IAB node joining the network according to an embodiment of this application, including: IAB-donor2 (IAB node), IAB-donor1, IAB-donor (host node), and core network. For simplicity, IAB-donor2 is used as an example to illustrate the network joining process. The IAB node mentioned below usually refers to IAB-donor2, the host node usually refers to IAB-donor (the host node for IAB node joining the network), and the core network usually refers to the 5G core network (5GC).

[0266] The process of an IAB node joining the network may include the following steps:

[0267] Step 1. IAB-MT settings.

[0268] Typically, an IAB-MT needs to access the cell in a manner similar to a regular UE, establish an RRC connection with the host node, and indicate that it is an IAB node when establishing the RRC connection. For example, the RRCSetupComplete message carries indication information of the IAB node.

[0269] After the RRC connection between the host node and the IAB-MT is established, the host node can send the IAB-MT indication information to the AMF network element of the core network. This allows the AMF to authenticate the IAB-MT and determine whether it is in an authorized state. Specifically, the IAB-MT indication information can be carried in the UE initial message (e.g., INITIAL UE MESSAGE) sent by the host node's CU to the AMF network element of the core network.

[0270] Optionally, the AMF network element can also return authentication information (e.g., IAB Authorized information element) to the host node. This authentication information can be carried in the UE initial context message of IAB-MT. For example, the IAB Authorized information element can be carried in the INITIAL CONTEXT SETUP REQUEST message.

[0271] If the indication information returned by the AMF network element indicates that the IAB-MT is in an authorized state (the value of IAB Authorized is authorized), then the subsequent network entry procedure will be executed. If the indication information returned by the AMF network element indicates that the IAB-MT is in an unauthorized state (the value of IAB Authorized is not authorized), then the subsequent network entry procedure will not be executed. Optionally, if the host node has already allocated backhaul link configuration information to the IAB-MT, the host node can delete the configuration information of that backhaul link.

[0272] In some possible scenarios, whether IAB node authorization is allowed may also be related to time and space. For example, only some IABs may be allowed to provide services during the morning peak hours, or IAB nodes may have their own specific service ranges. Therefore, when the authorization status of an IAB node changes, the AMF will also send a UE context modification request (e.g., UE CONTEXT MODIFICATION REQUEST) message to the host node, which may carry the latest authorization status of the IAB node.

[0273] In one possible implementation, after receiving the authorization status indication for the IAB node from the AMF, the host node will, based on the indication information (the value of IAB Authorized), enable or disable the IAB node to provide services through its own implementation.

[0274] To illustrate the subsequent network access process, we can assume the network element authorization status, i.e., the value of IAB Authorized is authorized.

[0275] Step 2-1. Establish the backhaul link RLC channel.

[0276] When the IAB node is in an authorized state, the host node configures the backhaul link RLC channel and performs routing configuration via RRC messages. At this time, only a default backhaul radio link control channel (default BH RLC CH) and a default routing ID are configured for use when the F1 interface is initially established.

[0277] Step 2-2. Update the routes.

[0278] In addition to configuring routes for IAB nodes, it also updates routes between IAB nodes and the host node. As shown in Figure 8, IAB-donor1 is the node between IAB-donor2 and IAB-donor. After configuring the routes for IAB-donor2, it also updates the routes for IAB-donor1 to inform intermediate nodes (e.g., IAB-donor1) how to select the next-hop link and the next-hop RLC Channel when receiving or sending data packets from or to IAB-donor2.

[0279] Step 3. IAB-DU settings.

[0280] The IAB node's DU can use the default configuration obtained in step 2-1 (e.g., default BH RLC CH and default routing ID) to send a request message to the migrated host node to establish an F1 interface. Optionally, the request message may include the configuration information of the cell under the IAB node's DU. After receiving the request message, the host node can return information indicating that the F1 interface establishment is complete to the IAB node. For example, this information can be carried in an F1 interface message, and the cell can be activated to complete the migration of the IAB-DU. At this point, the IAB node has completed its network access and can provide services to the UE and the next-hop IAB-MT.

[0281] The above content provides an example of the IAB node's network entry process. After an IAB node completes its network entry, there may be IAB node migrations, including the migration of IAB-MT and IAB-DU.

[0282] In some possible scenarios, during the IAB-MT migration process, the AMF network element will send the IAB node's authorization status information to the host node during the handover procedure. For example, the RAN3 meeting has agreed that during the IAB-MT migration process, the IAB node's authorization information will be carried in the PATH SWITCH REQUEST ACK message. The PATH SWITCH REQUEST-PATH SWITCH REQUEST ACK message is information exchanged between the host node and the AMF, used to inform the AMF that the IAB node has switched to the host node, and to instruct the AMF to send downlink data from the UE to the host node.

[0283] In other possible scenarios, during the IAB-MT handover request phase, the source host node sends the IAB node's authorization status indication information to the target host node. Compared to carrying the IAB node's authorization status information in a PATH SWITCH REQUEST ACK message and sending it to the target host node, this allows the target host node to obtain the IAB node's authorization status more quickly. For example, during the IAB-MT handover request phase, the source host node carries the IAB node's authorization status indication information in a HANDOVER REQUEST message.

[0284] After the target host node receives the authorization status indication information (HANDOVER REQUEST) from the IAB node, if the authorization status indication information in the message indicates that the IAB node is in an unauthorized state, then the target host node may not send backhaul link configuration information (including: default BAP configuration, BAP address or IP address, etc.) to the IAB node.

[0285] However, the authorization status of an IAB node is usually related to time and space. The authorization status of an IAB node under the source host node is usually not the same as the authorization status under the target host node. For example, the authorization status of an IAB node under the source host node may be authorized, but the authorization status of an IAB node under the target host node may be unauthorized. The authorization of an IAB node is ultimately based on the authentication result of the AMF network element, for example, the authorization indication information in the PATH SWITCH REQUEST ACK message received by the target host node.

[0286] Therefore, under normal circumstances, the target host node will assume that the IAB node is in an authorized state and send the backhaul link configuration (including: default BAP configuration, BAP address or IP address, etc.) to the IAB node during the IAB-MT migration process. For example, the backhaul link configuration information is carried in an RRC message and sent to the IAB node.

[0287] However, the IAB node migrating to the target host node may still be in an unauthorized state. When the IAB node switches from an unauthorized state to an authorized state, it should follow the network entry process shown in Figure 8 to obtain the backhaul link configuration information and establish an F1 interface. Understandably, in this case, the relay node obtains backhaul link configuration information twice: once during the IAB-MT migration and again after switching to an authorized state. Currently, there is no clear solution for handling / using the two sets of backhaul link configuration information. Without further processing, two sets of backhaul link configurations may exist, leading to conflicts in backhaul link configurations and high signaling overhead.

[0288] It should be noted that all indication information regarding IABs in this application embodiment can be replaced with indication information for Mobile IABs. For example, IAB authorization information can include both IAB authorization information and Mobile IAB authorization information. For instance, an IAB Authorized information cell can be used to carry IAB authorization information, and a mIAB Authorized information cell can be used to carry IAB node authorization information. Exemplarily, if the IAB node is a mIAB, then the mIAB Authorized information cell is used to carry the authorization status of the IAB node; otherwise, the IAB Authorized information cell can be used to carry the authorization status of the IAB node.

[0289] In view of this, the embodiments of this application provide a new communication method that can avoid the situation of having two sets of backhaul link configurations, thereby ensuring that there will be no conflict in the backhaul link configuration and no additional signaling overhead.

[0290] Please refer to Figure 9, which is a flowchart illustrating a communication method provided in an embodiment of this application. This communication method is applied in the field of communication technology, such as communication in IAB networks, and includes, but is not limited to, the following steps:

[0291] S901: Configuration for relay node to release backhaul link.

[0292] S902: The first host node sends the second configuration information to the relay node, and the relay node receives the second configuration information from the first host node accordingly.

[0293] It is understood that the relay node in this application embodiment can be a device equipped with a processor / chip that can execute computer execution instructions, or it can be a processor / chip that can execute computer execution instructions. This application embodiment does not limit this. The relay node in this application embodiment includes a terminal-side part facing the parent node and a network-side part facing the child node. For example, it can include MT and DU, or it can include MT and gNB. This application embodiment does not limit this. Among them, the DU migration and MT migration of the relay node are completely decoupled. Therefore, the host node connected to the MT of the relay node and the host node connected to the DU can be different. The MT of the relay node is connected to the first host node, and the DU of the relay node is connected to the third host node. Optionally, when the communication method in this application embodiment is applied to an IAB network, the relay node can be an IAB node, the MT of the IAB node is connected to the first host node, and the DU of the IAB node is connected to the third host node. For example, the relay node can be a mIAB node, such as the relay node composed of IAB-MT2 and IAB-DU2 in Figure 7, which is used to execute the communication method in the embodiments of this application. This can avoid the situation of having two sets of backhaul link configurations, thereby ensuring that there will be no conflict in the backhaul link configuration and no additional signaling overhead.

[0294] It is understood that the first host node in this application embodiment can be a device equipped with a processor / chip that can execute computer execution instructions, or it can be a processor / chip that can execute computer execution instructions. This application embodiment does not limit this. In this application embodiment, the first host node is the target CU corresponding to the MT of the relay node. The first host node is connected to the MT of the relay node. Optionally, when the communication method in this application embodiment is applied to an IAB network, the relay node can be an IAB node, and the first host node can be connected to the MT of the IAB node. For example, the first host node can be CU2 in Figure 7 above, used to execute the communication method in this application embodiment. This can avoid the situation of two sets of backhaul link configurations, thereby ensuring that there will be no conflict in the backhaul link configuration and no additional signaling overhead.

[0295] It is understood that the second host node in this application embodiment can be a device equipped with a processor / chip that can execute computer execution instructions, or it can be a processor / chip that can execute computer execution instructions. This application embodiment does not limit this. In this application embodiment, the second host node is the source CU corresponding to the MT of the relay node. It is understood that the MT of the relay node is migrated from the second host node to the first host node. Optionally, when the communication method in this application embodiment is applied to an IAB network, the relay node can be an IAB node, and the second host node can be the source CU corresponding to the MT of the IAB node. It is understood that the MT of the IAB node is migrated from the second host node to the first host node. For example, the first host node can be CU1 in Figure 7 above, used to execute the communication method in this application embodiment. This can avoid the situation of two sets of backhaul link configurations, thereby ensuring that there will be no conflict in the backhaul link configuration and no additional signaling overhead.

[0296] Specifically, S901 and / or S902 above are executed when the following triggering conditions are met:

[0297] When the first triggering condition is met, the relay node releases the configuration of the backhaul link. In this case, the first triggering condition can be understood as the condition that triggers the relay node to release the configuration of the backhaul link.

[0298] The first triggering condition mentioned above includes, but is not limited to, any one or more of the following:

[0299] (1) Relay nodes perform mobile terminal (MT) migration.

[0300] (2) The relay node is in an unauthorized state.

[0301] (3) The relay node receives first configuration information from the first host node, which is used to indicate the configuration of the backhaul link.

[0302] The release of the backhaul link configuration in this application embodiment can be understood as the backhaul link configuration failing, or the configuration of the backhaul link not being used, or the backhaul link configuration not being used, or the backhaul link having already been constructed based on the configuration of the backhaul link, and then releasing the already constructed backhaul link, etc. Releasing the backhaul link configuration should not be understood merely as the backhaul link having already been constructed based on the configuration of the backhaul link, and then releasing the already constructed backhaul link.

[0303] Optionally, relay node performing mobile terminal (MT) migration can refer to the process after the first host node receives the MT migration instruction information (e.g., HANDOVER REQUEST message) from the second host node, but before the MT re-establishes the F1 interface through the first host node.

[0304] Optionally, the relay node being in an unauthorized state can be indicated by the handover request message (HANDOVER REQUEST message) sent by the second host node to the first host node including information indicating that the relay node is in an unauthorized state.

[0305] Alternatively, the access and mobility management function (AMF) can send information to the first host node indicating that the relay node is in an unauthorized state. Specifically, the AMF sends a PATH SWITCH REQUEST ACK message to the first host node, carrying the relay node's authorization information to indicate that the relay node is in an unauthorized state.

[0306] Alternatively, the AMF can directly send information indicating that the relay node is in an unauthorized state to the relay node's MT. Specifically, the AMF sends a NAS message to the relay node's MT, which carries information about the authorized state of the relay node's MT, indicating that the relay node's MT is in an unauthorized state.

[0307] Optionally, the aforementioned first configuration information can be carried in an RRC message, such as the RRC reconfiguration message RRCReconfiguration. It may include one or more of the following: default BAP configuration, BAP address, and IP address, etc.

[0308] In an IAB network, during the MT migration process of an IAB node, the target CU will by default allocate backhaul link configurations to the IAB node, including one or more of the following: default BAP configuration, BAP address, and IP address. After the MT migration is complete, if the IAB node changes from an unauthorized state to an authorized state, it will perform an inbound process and obtain backhaul link configurations again. For example, during the migration of an IAB node's MT to the first host node, the first host node usually defaults to an authorized state for the IAB node's MT and allocates backhaul link configurations to it. After the IAB node's MT handover is complete, the AMF will send the authorization information (including authorized or unauthorized state) of the IAB node's MT to the first host node. How to handle the backhaul link configurations already allocated to the IAB node's MT if the IAB node's MT is in an unauthorized state is a problem that needs to be solved. Furthermore, if the IAB node's MT subsequently changes from an unauthorized state to an authorized state, the IAB node will re-enter the network and obtain a new backhaul link configuration. At this point, whether the IAB node uses the new or old backhaul link configuration is also an issue that needs to be addressed. Furthermore, allocating two sets of backhaul link configurations to the IAB node may cause usage conflicts and increase signaling overhead.

[0309] However, the implementation of this application explicitly specifies the triggering conditions for releasing backhaul link configurations. This ensures that, upon meeting the first triggering condition, relay nodes will promptly release backhaul link configurations, allowing temporarily unused backhaul link configurations to be released and potentially used by other nodes, thus improving resource utilization. Furthermore, it avoids assigning two sets of backhaul link configurations to IAB nodes, thereby preventing backhaul link configuration conflicts and reducing signaling overhead during MT migration.

[0310] In one possible implementation, the backhaul link configuration is not released under the following triggering conditions: the relay node performs a mobile terminal (MT) migration; the relay node is in an authorized state; and the relay node receives first configuration information from the first host node, the first configuration information indicating the configuration of the backhaul link.

[0311] In one possible implementation, the first configuration information mentioned above includes at least one of the following: the default Backhaul Link Adaptor Layer Protocol (BAP) configuration, the BAP address, and the Internet Protocol (IP) address.

[0312] In this application embodiment, a possible specific implementation of the first configuration is provided. Specifically, in the MT migration scenario of the IAB node, the first host node sends a first configuration to the IAB node. The first configuration may include at least one of the following: default BAP configuration, BAP address, and IP address, etc. It should be noted that the first configuration information may be carried in one RRC message or in multiple RRC messages; this application embodiment does not limit this.

[0313] In one possible implementation, the above method further includes:

[0314] When the relay node switches to authorized state, the first host node sends second configuration information to the relay node. Correspondingly, the relay node receives the second configuration information from the first host node. The second configuration information is used to indicate the configuration of the backhaul link.

[0315] The relay node switching to an authorized state can refer to the AMF sending an indication message to the first host node, indicating that the relay node is in an authorized state. This indication message can be carried by the PATH SWITCH REQUEST ACK message in the handover process. Alternatively, it can refer to the AMF sending a Non-Access Stratum (NAS) message to the MT of the IAB node, indicating that the IAB node is in an authorized state. It can also refer to the NAS layer of the IAB node sending an indication message to the AS layer, indicating that the IAB node is in an authorized state. This embodiment of the application does not limit which specific instance of the relay node switching to an authorized state refers to.

[0316] In this process, the relay node receives second configuration information from the first host node, and correspondingly, the first host node generates / sends second configuration information. The second configuration information is the configuration information for the backhaul link, which is the backhaul link between the relay node and the first host node.

[0317] Optionally, the second configuration information includes at least one of the following: default BAP configuration, BAP address, and Internet Protocol (IP) address. This application does not limit the implementation of this method.

[0318] It should be noted that the second configuration information can be carried in one RRC message or in multiple RRC messages; this application embodiment does not limit this.

[0319] This application provides a possible implementation of a relay node. Specifically, in a scenario where a relay node switches from an unauthorized state to an authorized state, the relay node receives second configuration information from the first host node to construct a backhaul link for communication. It is understood that in this application embodiment, if the relay node is in an unauthorized state, the configuration information (first configuration information) allocated to the relay node will be released. Switching from an unauthorized state to an authorized state avoids the simultaneous existence of two sets of backhaul link configurations, thus preventing configuration conflicts and reducing signaling overhead. Furthermore, the second configuration information is the backhaul link configuration information allocated to the relay node by the first host node after the relay node is reauthorized. This information ensures that the backhaul link configuration is based on the latest resource status, thereby improving resource allocation performance.

[0320] In one possible implementation, the second configuration information mentioned above includes an IP address.

[0321] It should be noted that, in the embodiments of this application, "the second configuration information includes an IP address" generally means that the second configuration information includes one and only one IP address. In other words, when a relay node switches from an unauthorized state to an authorized state, the configuration information received by the relay node includes one and only one IP address. That is, the second configuration information may also include the default BAP configuration or BAP address, but it includes one and only one IP address, not multiple IP addresses.

[0322] Understandably, in scenarios where a relay node switches from an unauthorized to an authorized state, the relay node receives second configuration information from the first host node to build a backhaul link and initiate communication. This second configuration information includes exactly one IP address, not multiple IP addresses. It's understandable that building a backhaul link requires one or more IP addresses; however, the IP address resources that the host node can allocate are limited. Allocating a single IP address to the relay node satisfies the need for building the backhaul link. If the relay node requires more IP addresses, it then requests more IP addresses from the first host node.

[0323] Optionally, one of the IP addresses in the second configuration information above can be carried in an RRC message.

[0324] Optionally, one of the IP addresses in the second configuration information above can be used for the control plane protocol (F1-C). This F1-C can manage the interface between the relay node and the first host node, manage the relay node's DU, and execute UE context-related configurations.

[0325] In this embodiment of the application, the second configuration information includes only one IP address, which can save IP address resources and make full use of the limited IP address resources in the first host node.

[0326] In one possible implementation, the relay node sends second information to the first host node, and the first host node receives the second information from the relay node, the second information being used to request at least one IP address.

[0327] In this embodiment of the application, the second information is used to request at least one IP address, and correspondingly, the first host node will allocate at least one IP address to the relay node according to the second information.

[0328] The implementation of this application does not limit the use of the aforementioned IP addresses. For example, they can be used for F1-C or User Plane Protocol F1-U, etc.

[0329] Optionally, the second information can be carried in an RRC message, such as IABOtherInformation.

[0330] Optionally, if the relay node requires more IP addresses, a second message is sent to the first host node. This application does not limit why the relay node needs more IP addresses, or the purpose of the IP addresses. For example, a relay node may need more IP addresses when it needs to transmit more traffic back.

[0331] This application provides a specific implementation method for the second information. Specifically, in scenarios where a relay node requires more IP addresses, the relay node sends the second information to the first host node. It is understood that the first host node will allocate at least one IP address to the relay node based on the second information, enabling the relay node to perform / complete the corresponding task. This method of allocating IP addresses to relay nodes according to their needs avoids allocating unused IP addresses, thereby saving IP address resources and improving IP address utilization.

[0332] In one possible implementation, the second configuration information described above does not include an IP address; the method further includes:

[0333] When the second triggering condition is met, the relay node sends third information to the first host node. Correspondingly, the first host node receives the third information from the relay node, which is used to request an IP address.

[0334] The second triggering condition mentioned above includes at least one of the following:

[0335] The second configuration information mentioned above includes the default BAP configuration; or, the second configuration information mentioned above includes the BAP address; or, the relay node receives the fourth information, which is used to indicate that the relay node is in an authorized state.

[0336] The second triggering condition in the embodiments of this application includes, but is not limited to, one or more of the following: the second configuration information includes a default BAP configuration; or, the second configuration information includes a BAP address; or, the relay node receives fourth information, which is used to indicate that the relay node is in an authorized state.

[0337] In this context, "relay node receiving the fourth message" typically refers to the relay node receiving the fourth message from the AMF (Advanced Management Function). In response, the AMF sends the fourth message back to the relay node. Generally, the AMF sends the fourth message to the relay node's NAS (Navigation Attached Function) layer, or the NAS layer sends the fourth message to the AS (Agency Attached Function) layer. That is, "relay node receiving the fourth message from the AMF" can be understood as the relay node receiving the fourth message from the AMF through the NAS layer, or the relay node receiving authorization information from the AMF at the NAS layer and then receiving the fourth message from the NAS layer through the AS layer.

[0338] In this embodiment of the application, when the second triggering condition is met, the relay node sends third information to the first host node. Correspondingly, the first host node also receives the third information from the relay node and sends one or more IP addresses to the relay node according to the third information.

[0339] Among them, at least one IP address used for F1-C is included in the IP address requested through the aforementioned third information request.

[0340] Optionally, the IP address in the third information request may also include the IP address used for F1-U.

[0341] This application provides a possible implementation of third information. Specifically, in scenarios where a second triggering condition is met, or where a relay node requires an IP address, the relay node sends third information to the first host node to request an IP address. It is understood that in this application's implementation, when the first host node sends backhaul link configuration to the relay node, it does not automatically assign an IP address to the relay node. Only when the second triggering condition is met will the relay node send third information to the first host node and request one or more IP addresses.

[0342] In one possible implementation, the fourth piece of information comes from the non-access stratum NAS or access stratum AS of the relay node.

[0343] Understandably, the AMF is responsible for authenticating the authorization status of relay nodes. After authentication, the AMF sends the authentication result to the relay node. For example, the AMF sends authorization status indication information to the NAS layer of the relay node to indicate the authorization status of the relay node. Similarly, the NAS layer of the relay node sends indication information to the AS layer to indicate the authorization status of the relay node.

[0344] Optionally, the indication information sent by the AMF to the NAS layer can be carried in the NAS message.

[0345] Please refer to Figure 10, which is a flowchart illustrating another communication method provided in an embodiment of this application. It is understood that the steps in the embodiments of this application can be considered reasonable variations or supplements to the embodiments in Figure 9 above; or, it is understood that the communication method in the embodiments of this application can also be considered an embodiment that can be executed independently, and this application does not limit it in this regard. The communication method provided in the embodiments of this application is applied in the field of communication technology, such as communication in IAB networks.

[0346] It is understood that the CU1 involved in the communication method provided in this application embodiment can refer to the first host node in the communication method shown in Figure 9 above, and the IAB (including IAB-DU and IAB-MT) involved in the communication method provided in this application embodiment can refer to the relay node in the communication method shown in Figure 9 above, which will not be described again here.

[0347] This communication method includes, but is not limited to, the following steps:

[0348] Step 1: CU1 sends the first configuration information to IAB-MT. Correspondingly, IAB-MT receives the first configuration information from CU1. This first configuration information is used to establish a backhaul link between CU1 and IAB-MT. This first configuration information can be carried in an RRC message, such as an RRC reconfiguration message.

[0349] Step 2: The IAB node releases the backhaul link configuration, which is the backhaul link configuration indicated by the first configuration information mentioned above.

[0350] Optionally, the AMF sends a NAS message to the IAB node indicating that the IAB node is in an unauthorized state; alternatively, the IAB node's NAS layer sends an indication message to the AS layer, indicating that the IAB node is in an unauthorized state. The IAB node releases the aforementioned backhaul link configuration information.

[0351] It is understandable that if the AMF sends a NAS message to the IAB node indicating that the IAB node is in an authorized state, or if the IAB node's NAS layer sends an indication message to the AS layer indicating that the IAB node is in an authorized state, the IAB node may not release the aforementioned backhaul link configuration information.

[0352] Step 3-1: The AMF sends authorization indication information to CU1. For example, the AMF sends a UE CONTEXT MODIFICATION REQUEST message to CU1. Correspondingly, CU1 receives the UE CONTEXT MODIFICATION REQUEST message from the AMF. This UE CONTEXT MODIFICATION REQUEST message carries authorization indication information for the IAB node, indicating that the IAB node is in an authorized state. Specifically, the authorization state of the IAB node can be indicated by the IAB Authorized information element in the UE CONTEXT MODIFICATION REQUEST message, or it can be indicated by the mIAB Authorized information element in the UE CONTEXT MODIFICATION REQUEST message. This embodiment of the application does not limit this.

[0353] Step 3-2: The AMF sends authorization indication information to the relay node. For example, the AMF directly sends a NAS message to the IAB node. Correspondingly, the IAB node receives the NAS message from the AMF, which carries information indicating that the IAB node is in an authorized state. Specifically, the authorized state of the IAB node can be indicated by the IAB Authorized information element in the NAS message, or it can be indicated by the mIAB Authorized information element in the NAS message. This embodiment does not limit the specific indication.

[0354] It should be understood that the execution order of steps 3-1 and 3-2 is not limited in this embodiment of the application. For example, step 3-1 may be executed first, followed by step 3-2. Alternatively, step 3-2 may be executed first, followed by step 3-1.

[0355] Step 4: CU1 sends the second configuration information to IAB-MT. Correspondingly, IAB-MT receives the second configuration information from CU1. This second configuration information is used to establish a backhaul link between CU1 and IAB-MT. This second configuration information can be carried in an RRC message, such as an RRC reconfiguration message. This configuration information includes one or more of the following: default BAP configuration and BAP address.

[0356] Step 5: IAB-MT requests an IP address from CU1 (Option 1, a default IP address is assigned).

[0357] Optionally, before IAB-MT requests an IP address from CU1, CU1 will send an IP address to IAB-MT. For example, CU1 may send the IP address in an RRC message. Optionally, the RRC message used to send the IP address can be the same as the RRC message in step 4. Essentially, CU1 assigns an IP address to IAB-MT by default.

[0358] Optionally, one of the above IP addresses can be used for F1-C.

[0359] If the IAB-MT needs more IP addresses, it can send a request message to CU1 to request additional IP addresses. This request message can be carried in an RRC message, such as IABotherInformation.

[0360] It should be noted that the scheme shown in step 5 and the subsequent step 6 are two parallel schemes. In step 5, CU1 will by default allocate an IP address to IAB-MT for F1-C. In step 6, CU1 will not by default allocate an IP address to IAB-MT; IAB-MT can request an IP address from CU1 if the triggering conditions are met.

[0361] Step 6: IAB-MT requests an IP address from CU1 (Option 2, no default IP address assigned).

[0362] The IAB-MT requests an IP address from CU1 (e.g., by carrying the request information in an RRC message, such as IABOtherInformation) if the following triggering conditions are met. These triggering conditions include one or more of the following:

[0363] (1) IAB-MT receives the default BAP configuration.

[0364] (2) IAB-MT receives BAP address.

[0365] (3) Receive the instruction information through the NAS layer (indicating that the IAB node is in an authorized state).

[0366] (4) The NAS layer sends an instruction message to the AS layer (indicating that the IAB node is in an authorized state).

[0367] Among them, the IP address requested by IAB-MT from CU1 must include at least one IP address used for F1-C.

[0368] This application embodiment clarifies that during the IAB-MT migration process, if the IAB node is in an unauthorized state, the configuration information acquired by the IAB node is directly released, preventing the IAB node from having two backhaul link configurations. This avoids backhaul link configuration conflicts and reduces signaling overhead. Furthermore, the second configuration information is the backhaul link configuration information allocated to the IAB node by CU1 after the IAB node is reauthorized. This information ensures that the backhaul link configuration is based on the latest resource status, thereby improving resource allocation performance.

[0369] Please refer to Figure 11, which is a flowchart illustrating another communication method provided in an embodiment of this application. It is understood that the steps in the embodiments of this application can be considered reasonable variations or supplements to the embodiments in Figures 9 or 10 above; or, it is understood that the communication method in the embodiments of this application can also be considered an embodiment that can be executed independently, and this application does not limit this. The communication method provided in the embodiments of this application is applied in the field of communication technology, such as communication in IAB networks, and the communication method includes, but is not limited to, the following steps:

[0370] S1101: The relay node saves the configuration of the backhaul link, and correspondingly, the first host node generates / sends the configuration of the backhaul link.

[0371] S1102: The first host node sends the fifth message to the relay node, and the relay node receives the fifth message from the first host node.

[0372] It is understood that the relay node in this application embodiment can be a device equipped with a processor / chip that can execute computer execution instructions, or it can be a processor / chip that can execute computer execution instructions. This application embodiment does not limit this. The relay node in this application embodiment includes a terminal-side part facing the parent node and a network-side part facing the child node. For example, it can include MT and DU, or it can include MT and gNB. This application embodiment does not limit this. Among them, the DU migration and MT migration of the relay node are completely decoupled. Therefore, the host node connected to the MT of the relay node and the host node connected to the DU can be different. The MT of the relay node is connected to the first host node, and the DU of the relay node is connected to the third host node. Optionally, when the communication method in this application embodiment is applied to an IAB network, the relay node can be an IAB node, the MT of the IAB node is connected to the first host node, and the DU of the IAB node is connected to the third host node. For example, the relay node can be a mIAB node, such as the relay node composed of IAB-MT2 and IAB-DU2 in Figure 7, which is used to execute the communication method in the embodiments of this application. This can avoid the situation of having two sets of backhaul link configurations, thereby ensuring that there will be no conflict in the backhaul link configuration and no additional signaling overhead.

[0373] It is understood that the first host node in this application embodiment can be a device equipped with a processor / chip that can execute computer execution instructions, or it can be a processor / chip that can execute computer execution instructions. This application embodiment does not limit this. In this application embodiment, the first host node is the target CU corresponding to the MT of the relay node. The first host node is connected to the MT of the relay node. Optionally, when the communication method in this application embodiment is applied to an IAB network, the relay node can be an IAB node, and the first host node can be connected to the MT of the IAB node. For example, the first host node can be CU2 in Figure 7 above, used to execute the communication method in this application embodiment. This can avoid the situation of two sets of backhaul link configurations, thereby ensuring that there will be no conflict in the backhaul link configuration and no additional signaling overhead.

[0374] It is understood that the second host node in this application embodiment can be a device equipped with a processor / chip that can execute computer execution instructions, or it can be a processor / chip that can execute computer execution instructions. This application embodiment does not limit this. In this application embodiment, the second host node is the source CU corresponding to the MT of the relay node. It is understood that the MT of the relay node is migrated from the second host node to the first host node. Optionally, when the communication method in this application embodiment is applied to an IAB network, the relay node can be an IAB node, and the second host node can be the source CU corresponding to the MT of the IAB node. It is understood that the MT of the IAB node is migrated from the second host node to the first host node. For example, the first host node can be CU1 in Figure 7 above, used to execute the communication method in this application embodiment. This can avoid the situation of two sets of backhaul link configurations, thereby ensuring that there will be no conflict in the backhaul link configuration and no additional signaling overhead.

[0375] Specifically, S1101 and / or S1102 above are executed when the following triggering conditions are met:

[0376] When the fourth triggering condition is met, the relay node saves the backhaul link configuration. This fourth triggering condition can be understood as the condition that prompts the relay node to save the backhaul link configuration. Alternatively, it can be understood as the relay node still saving the backhaul link configuration even when the fourth triggering condition is met.

[0377] The fourth triggering condition mentioned above includes, but is not limited to, any one or more of the following:

[0378] (1) The relay node performs MT migration.

[0379] (2) The relay node is in an unauthorized state.

[0380] (3) The relay node receives third configuration information from the first host node. The third configuration information is used to indicate the configuration information of the backhaul link.

[0381] The configuration of the backhaul link in this embodiment may be stored in the memory of the relay node, or in other devices that allow the relay node to quickly obtain the configuration information. This embodiment does not limit this.

[0382] Optionally, relay node performing mobile terminal (MT) migration can refer to the process after the first host node receives the MT migration instruction information (e.g., HANDOVER REQUEST message) from the second host node, but before the MT re-establishes the F1 interface through the first host node.

[0383] Optionally, the relay node being in an unauthorized state can be indicated by the handover request message (HANDOVER REQUEST message) sent by the second host node to the first host node including information indicating that the relay node is in an unauthorized state. Specifically, the IAB Authorized information element in the HANDOVER REQUEST message can indicate the authorized state of the relay node, or the mIAB Authorized information element in the HANDOVER REQUEST message can indicate the authorized state of the relay node; this embodiment of the application does not limit this.

[0384] Alternatively, the access and mobility management function (AMF) can send information to the first host node indicating that the relay node is in an unauthorized state. Specifically, the AMF sends a PATH SWITCH REQUEST ACK message to the first host node, carrying relay node authorization information to indicate that the relay node is in an unauthorized state.

[0385] Alternatively, the AMF can directly send information indicating that the relay node is in an unauthorized state to the relay node's MT. Specifically, the AMF sends a NAS message to the relay node's MT, which carries information about the MT's authorized state, indicating that the MT is in an unauthorized state.

[0386] Optionally, the aforementioned third configuration information can be carried in an RRC message, such as an RRC reconfiguration message, which may include one or more of the following: default BAP configuration, BAP address, and IP address, etc.

[0387] In an IAB network, during the MT migration process of an IAB node, the target CU will by default allocate backhaul link configurations to the IAB node, including one or more of the following: default BAP configuration, BAP address, and IP address. After the MT migration is complete, if the IAB node changes from an unauthorized state to an authorized state, it will perform an inbound process and obtain backhaul link configurations again. For example, during the migration of an IAB node's MT to the first host node, the first host node usually defaults to an authorized state for the IAB node's MT and allocates backhaul link configurations to it. After the IAB node's MT handover is complete, the AMF will send the authorization information (including authorized or unauthorized state) of the IAB node's MT to the first host node. How to handle the backhaul link configurations already allocated to the IAB node's MT if the IAB node's MT is in an unauthorized state is a problem that needs to be solved. Furthermore, if the IAB node's MT subsequently changes from an unauthorized state to an authorized state, the IAB node will re-enter the network and obtain a new backhaul link configuration. At this point, whether the IAB node uses the new or old backhaul link configuration is also an issue that needs to be addressed. Furthermore, allocating two sets of backhaul link configurations to the IAB node may cause usage conflicts and increase signaling overhead.

[0388] It is understood that the embodiment shown in Figure 11 differs from the embodiment shown in Figure 9 in that the embodiment shown in Figure 11 does not consider whether the relay node is authorized (e.g., whether the relay node is in an authorized state or an unauthorized state), and the relay node saves the received backhaul link configuration information. This differs from the embodiment shown in Figure 9, which only saves the backhaul link configuration information received by the relay node when the relay node is in an authorized state. Both the embodiments shown in Figure 11 and Figure 9 can avoid conflicts in backhaul link configurations and reduce signaling overhead during MT migration. The difference lies in that the embodiment shown in Figure 11 can activate the relay node based on the saved backhaul link configuration as soon as the relay node obtains authorization, achieving rapid activation of the relay node. The embodiment shown in Figure 9 can promptly release unused backhaul link configurations, improving resource utilization. Furthermore, the embodiment shown in Figure 9 can obtain a backhaul link configuration generated based on the latest resource status after the relay node obtains authorization, thereby improving resource allocation performance.

[0389] In one possible implementation, the third configuration information of the backhaul link is still preserved under the following conditions: the relay node performs MT migration; the relay node is in an authorized state; and the relay node receives the third configuration information from the first host node, the third configuration information being used to indicate the configuration information of the backhaul link.

[0390] In one possible implementation, the above method further includes:

[0391] The aforementioned relay node receives the fifth information, which indicates that the relay node is in an authorized state; the aforementioned relay node performs backhaul link transmission based on the aforementioned configuration information, and the backhaul link transmission includes establishing the F1 interface of the aforementioned relay node.

[0392] In this application, a possible specific implementation of the fifth information is provided. Specifically, the fifth information is used to indicate that the relay node is in an authorized state, and the fifth information may come from the AMF (Advanced Management Function). For example, the AMF sends the fifth information to the relay node via a NAS message, or the fifth information is carried in the indication information sent from the NAS layer of the relay node to the AS layer. It is understood that after the relay node changes from an unauthorized state to an authorized state, the relay node performs backhaul link transmission based on the above configuration information, which allows the relay node to start up quickly and avoids backhaul link configuration conflicts.

[0393] The backhaul link transmission includes establishing the F1 interface of the relay node. For example, using the backhaul link constructed with the above configuration information, the relay node sends an F1 application protocol (F1AP) message to the F1 anchor CU of the relay node. Specifically, an F1 interface message can be sent to the F1 anchor CU through the backhaul link constructed above to request the establishment of the relay node's F1 interface.

[0394] Please refer to Figure 12, which is a flowchart illustrating another communication method provided in an embodiment of this application. It is understood that the steps in the embodiments of this application can be considered reasonable variations or supplements to the embodiments in Figures 9, 10, or 11 above; or, it is understood that the communication method in the embodiments of this application can also be considered as an embodiment that can be executed independently, and this application does not limit this. The communication method provided in the embodiments of this application is applied in the field of communication technology, such as communication in IAB networks, and the communication method includes, but is not limited to, the following steps:

[0395] S1201: The second host node sends a seventh message to the first host node, and correspondingly, the first host node receives the seventh message from the second host node. This seventh message is used to indicate that the relay node is in an unauthorized state.

[0396] S1202: The first host node sends the backhaul link configuration to the relay node, and the relay node receives the backhaul link configuration from the first host node.

[0397] In this embodiment of the application, the relevant descriptions of the first host node, the second host node, and the relay node are as described in Figure 11 above, and will not be repeated here.

[0398] Optionally, the seventh piece of information can be carried in the relay node's MT migration request message, such as the HANDOVER REQUEST message.

[0399] Optionally, the configuration information for the backhaul link can be carried in a radio resource control (RRC) message, such as an RRCReconfiguration message.

[0400] Optionally, the configuration information for the backhaul link may include one or more of the following: default BAP configuration, BAP address, and IP address.

[0401] Optionally, the above IP address can be used at least for F1-C.

[0402] In an IAB network, during the MT migration of an IAB node, the second host node may send an indication of the relay node's authorization status to the first host node. For example, this indication can be carried in a HANDOVER REQUEST message. It is understood that the authorization status indicated by this indication typically refers to the relay node's authorization status under the second host node. For instance, if the relay node is in an authorized status under the second host node, the indication indicates that the relay node is in an authorized status. Similarly, if the relay node is in an unauthorized status under the second host node, the indication indicates that the relay node is in an unauthorized status. Specifically, the IAB Authorized information element in the HANDOVER REQUEST message can indicate the IAB node's authorization status under the second host node, or the mIAB Authorized information element in the HANDOVER REQUEST message can indicate the IAB node's authorization status under the second host node; this embodiment does not limit the specific indication.

[0403] If the primary host node receives a message indicating that the relay node is in an unauthorized state, it may not send backhaul link configuration information to the relay node. However, whether the relay node ultimately becomes authorized depends on the AMF's indication. If, after AMF authentication, the relay node becomes authorized, and the primary host node then sends backhaul link configuration information to the relay node, it will affect the relay node's startup speed.

[0404] However, this application embodiment explicitly provides a method for the first host node to handle situations where the second host node indicates that the relay node is in an unauthorized state. Specifically, the first host node ignores the indication information from the second host node, that is, it does not consider whether the indication information from the second host node indicates that the relay node is in an authorized state, and directly sends the backhaul link configuration information to the relay node. This ensures that if the AMF authentication result is that the relay node is in an authorized state, the relay node directly uses the backhaul link configuration information. On the one hand, this achieves the effect of quickly enabling the relay node; on the other hand, it avoids the need for the first host node to send the backhaul link configuration information to the relay node again when the relay node switches to an authorized state, thus avoiding conflicts in the backhaul link configuration.

[0405] In the embodiment shown in Figure 12, the first host node, regardless of whether the relay node is authorized (e.g., the relay node is in an authorized state or an unauthorized state), sends backhaul link configuration information to the relay node after receiving the MT migration request from the relay node. Corresponding to the embodiment shown in Figure 11, regardless of whether the relay node is authorized (e.g., the relay node is in an authorized state or an unauthorized state), the relay node saves the received backhaul link configuration information. In practical implementation, the embodiments shown in Figures 11 and 12 work together to quickly enable the relay node when it switches to an authorized state.

[0406] In one possible implementation, the first host node receives an indication from the second host node indicating that the relay node is in an authorized state, and still sends backhaul link configuration information to the relay node.

[0407] In one possible implementation, the above method further includes:

[0408] If the fourth condition is met, the aforementioned first host node retains the above configuration information;

[0409] The fourth condition mentioned above includes:

[0410] The first host node receives a sixth message from the Access and Mobility Management Function (AMF) element, the sixth message indicating that the relay node is in an unlicensed state; and the relay node is connected to the first host node.

[0411] The sixth piece of information is used to indicate that the relay node is in an unauthorized state. This sixth piece of information can be carried in the UE CONTEXT MODIFICATION REQUEST message. Alternatively, it can be carried in a NAS message sent to the relay node, which carries information indicating that the relay node's authorized state is "authorized". Specifically, it can be the IAB Authorized element in the UE CONTEXT MODIFICATION REQUEST message indicating that the IAB node is in an authorized state; it can also be the mIAB Authorized element in the UE CONTEXT MODIFICATION REQUEST message indicating that the IAB node is in an authorized state; it can also be the IAB Authorized element in the NAS message indicating that the IAB node is in an authorized state; or it can be the mIAB Authorized element in the NAS message indicating that the IAB node is in an authorized state. This embodiment of the application does not limit this specific instance.

[0412] The connection between the relay node and the first host node mentioned above usually means that the relay node and the first host node are not disconnected. Specifically, it means that the MT of the relay node is connected to the first host node. For example, the backhaul link between the MT of the relay node and the first host node is not disconnected, or the MT of the relay node has not performed a new MT migration, etc.

[0413] In one possible implementation, the first host node retains configuration information if the following conditions are met: the first host node receives indication information from the AMF indicating that the relay node is in an authorized state; and the relay node is connected to the first host node.

[0414] In one possible implementation, the above method further includes:

[0415] If the relay node loses connection with the first host node, delete the configuration information.

[0416] This application provides a possible specific implementation for deleting backhaul link configuration information. Specifically, when the relay node disconnects from the first host node, the backhaul link configuration information of the first host node is deleted. This allows unused backhaul link configurations to be released in a timely manner, and if possible, these backhaul link configurations can be used by other nodes, thereby improving resource utilization.

[0417] It is understandable that the relay receiving node disconnecting from the first host node could mean that the relay node's MT (Metal Transporter) is disconnected from the first host node, or that the backhaul link between the relay node's MT and the first host node is broken, or that the relay node's MT has undergone MT migration, etc.

[0418] The aforementioned deletion of configuration information on the first host node could mean either releasing the configuration information or adjusting the configuration information to be usable by other nodes.

[0419] Please refer to Figure 13, which is a flowchart illustrating another communication method provided in an embodiment of this application. It is understood that the steps in the embodiments of this application can be considered reasonable variations or supplements to the embodiments in Figure 9 above; or, it is understood that the communication method in the embodiments of this application can also be considered an embodiment that can be executed independently, and this application does not limit it in this regard. The communication method provided in the embodiments of this application is applied in the field of communication technology, such as communication in IAB networks.

[0420] It is understood that the CU1 involved in the communication method provided in this application embodiment can refer to the first host node in the communication method shown in Figure 11 or Figure 12 above, the CU2 involved in the communication method provided in this application embodiment can refer to the second host node in the communication method shown in Figure 11 or Figure 12 above, and the IAB (including IAB-DU and IAB-MT) involved in the communication method provided in this application embodiment can refer to the relay node in the communication method shown in Figure 11 or Figure 12 above, and will not be described again here.

[0421] This communication method includes, but is not limited to, the following steps:

[0422] Step 1: CU1 sends a handover request to CU2, and CU2 receives the handover request from CU1 accordingly. For example, the handover request information can be carried in a Handover Request message. Optionally, the handover request information may include the authorization status of the IAB-MT under CU1. Specifically, it can be that the IAB Authorized information element in the Handover Request message indicates that the IAB node is in an authorized state, or it can be that the mIAB Authorized information element in the Handover Request message indicates that the IAB node is in an authorized state. This embodiment of the application does not limit this.

[0423] Step 2: CU2 sends the backhaul link configuration information to IAB-MT, and correspondingly, IAB-MT receives the backhaul link configuration information from CU2. For example, the backhaul link configuration information can be carried in an RRC message, such as an RRCReconfiguration message. Specifically, this RRC message can be forwarded to IAB-MT through CU1; for example, the transmission path of this RRC message is CU2-CU1-DU1-IAB-MT.

[0424] Optionally, this configuration information may include one or more of the following: default BAP configuration, BAP address, and IP address.

[0425] Normally, if CU2 receives an indication from CU1 that the IAB node is in an unauthorized state, CU2 will not send configuration information to the IAB node. However, in this embodiment, CU2 ignores the indication from CU1. Even if CU1 indicates that the IAB node is in an unauthorized state, it still allocates configuration information to IAB-MT to quickly enable the IAB node when it receives an indication from AMF that the IAB node is in an authorized state.

[0426] Step 3: The IAB node saves the backhaul link configuration information. Even if the IAB node knows it is in an unauthorized state, it still saves the backhaul link configuration information obtained in Step 2. Similarly, if the IAB node knows it is in an authorized state, it will also save the backhaul link configuration information obtained in Step 2.

[0427] Step 4: The IAB-MT performs a handover, establishing an RRC connection between the IAB-MT and CU2. CU2 sends a UE initial message (e.g., INITIAL UE MESSAGE) to the AMF network element. Optionally, the RRCSetupComplete and INITIAL UE MESSAGE messages may carry indication information of the IAB node. Specifically, the RRCSetupComplete and INITIAL UE MESSAGE messages may carry indication information of the IAB node, and the RRCSetupComplete and INITIAL UE MESSAGE messages may carry indication information of the mIAB node; this embodiment of the application does not limit this.

[0428] Step 5: The AMF sends IAB node authorization indication information to CU2. Correspondingly, CU2 receives the IAB node authorization indication information from the AMF. This authorization indication information is used to indicate that the IAB node is in an unauthorized state. For example, the authorization indication information is carried in the PATH SWITCH REQUEST ACK message sent by the AMF to CU2, indicating that the IAB node is in an unauthorized state. Specifically, the IAB Authorized information element in the PATH SWITCH REQUEST ACK message can indicate that the IAB node is in an authorized state, or the mIAB Authorized information element in the PATH SWITCH REQUEST ACK message can indicate that the IAB node is in an authorized state. This embodiment of the application does not limit this.

[0429] Step 6: Even if the AMF indicates that the IAB node is in an unauthorized state, CU2 still saves the configuration information of the backhaul link. It should be noted that CU2 can save the above-mentioned backhaul link configuration information before the next MT migration of IAB-MT.

[0430] Step 7-1: The AMF sends IAB node authorization indication information to CU2. Correspondingly, CU2 receives the IAB node authorization indication information from the AMF. This authorization indication information is used to indicate that the IAB node is in an authorized state. For example, the authorization indication information is carried in the UE CONTEXT MODIFICATION REQUEST message sent by the AMF to CU2, and indicates that the IAB node is in an authorized state. Specifically, it could be the IAB Authorized information element in the UE CONTEXT MODIFICATION REQUEST message indicating that the IAB node is in an authorized state, or it could be the mIAB Authorized information element in the UE CONTEXT MODIFICATION REQUEST message indicating that the IAB node is in an authorized state. This embodiment of the application does not limit this.

[0431] Step 7-2: The AMF sends authorization indication information to the IAB node. For example, the AMF sends a NAS message to the IAB node. Correspondingly, the IAB node receives a NAS message from the AMF, which is used to indicate that the IAB node is in an authorized state.

[0432] Step 8: Construct the backhaul link between IAB-MT and CU2. The IAB node performs backhaul link transmission based on the backhaul link configuration information saved in Step 3. For example, IAB-DU uses the saved backhaul link information to initiate the establishment of F1 interface through the topology under CU2 to the F1 anchor CU (the F1 anchor CU is the terminating CU of the F1 interface of IAB-DU, which can be a different CU or the same CU as CU2).

[0433] In this embodiment, the triggering conditions and circumstances for the IAB node and CU2 to save backhaul link configuration information are clearly given, and the backhaul link configuration information saved by the IAB node and CU2 is used to construct the backhaul link between the IAB node and CU2. On the one hand, this achieves the effect of quickly enabling the IAB node; on the other hand, it avoids the need for CU2 to send the backhaul link configuration information to the IAB node again when the IAB node switches to authorized status, thus avoiding conflicts in backhaul link configuration.

[0434] It is understood that Figure 13 can be seen as a specific description of the embodiments shown in Figures 11 and 12, illustrating in detail the possible steps in Figures 11 or 12, and thus possessing the beneficial effects corresponding to Figures 11 and 12. The embodiments shown in Figures 9 and 10 above demonstrate that when the relay node is in an unauthorized state, the relay node releases the backhaul link configuration, thereby improving resource utilization. The embodiments shown in Figures 11, 12, and 13 above demonstrate that both the relay node and / or the first host node ignore the authorized state of the relay node. The relay node saves the received backhaul link configuration, and the first host node saves the backhaul link configuration sent to the relay node. When the relay node switches to an authorized state, the saved backhaul link configuration is used to quickly activate the relay node.

[0435] Optionally, if an MT migration occurs in IAB-MT, the configuration information of the aforementioned backhaul links stored in CU2 needs to be released / deleted. Unused resources can be released, and if possible, these released resources can be used by other nodes to build backhaul links, improving resource utilization.

[0436] The methods of the embodiments of this application have been described in detail above. The following provides an apparatus for implementing any one of the methods in the embodiments of this application. For example, an apparatus is provided that includes a unit (or means) for implementing the steps performed by the device in any of the above methods.

[0437] As shown in Figure 14, the communication device 140 may include a communication unit 1401 and a processing unit 1402. The communication unit 1401 and the processing unit 1402 may be software, hardware, or a combination of software and hardware.

[0438] The communication unit 1401 can implement sending and / or receiving functions, and can also be described as a transceiver unit. The communication unit 1401 can also be a unit integrating an acquisition unit and a sending unit, wherein the acquisition unit is used to implement the receiving function, and the sending unit is used to implement the sending function. Optionally, the communication unit 1401 can be used to receive information sent by other devices, and can also be used to send information to other devices.

[0439] In one possible design, the communication device 140 may correspond to the relay node in the method embodiments shown in Figures 9, 10, 11, 12, and 13. For example, the communication device 140 may be a relay node or a chip within the relay node. The communication device 140 may include units for performing the operations performed by the relay node in the method embodiments shown in Figures 9, 10, 11, 12, and 13. Each unit in the communication device 140 is responsible for implementing the operations performed by the relay node in the method embodiments shown in Figures 9, 10, 11, 12, and 13. The descriptions of each unit are as follows:

[0440] Processing unit 1402 is used to release the configuration of the backhaul link when a first triggering condition is met; the backhaul link is the backhaul link between the relay node and the first host node.

[0441] The first triggering condition includes:

[0442] The relay node performs mobile terminal (MT) migration; and, the relay node is in an unauthorized state; and, the relay node receives first configuration information from the first host node, the first configuration information being used to indicate the configuration of the backhaul link.

[0443] or,

[0444] The processing unit 1402 is used to save the third configuration information of the backhaul link when the relay node meets the fourth triggering condition; the backhaul link is the backhaul link between the relay node and the first host node.

[0445] The fourth triggering condition includes:

[0446] The relay node performs MT migration; and, the relay node is in an unauthorized state; and, the relay node receives the third configuration information from the first host node, the third configuration information being used to indicate the configuration information of the backhaul link.

[0447] In one possible implementation, the device further includes:

[0448] The communication unit 1401 is used to receive second configuration information from the first host node.

[0449] or,

[0450] The communication unit 1401 is used to receive second configuration information from the first host node when the relay node switches to the authorized state.

[0451] or,

[0452] The communication unit 1401 is used to send second information to the first host node, the second information being used to request at least one IP address.

[0453] or,

[0454] Communication unit 1401 is used for the relay node to send third information to the first host node when the second triggering condition is met, the third information being used to request an IP address;

[0455] The second triggering condition includes at least one of the following:

[0456] The second configuration information includes a default BAP configuration; or, the second configuration information includes a BAP address; or, the relay node receives fourth information, which is used to indicate that the relay node is in an authorized state.

[0457] or,

[0458] The communication unit 1401 is used to receive fifth information, which indicates that the relay node is in an authorized state; the relay node performs backhaul link transmission based on the configuration information.

[0459] In one possible design, the communication device 140 may correspond to the first host node in the method embodiments shown in Figures 9, 10, 11, 12, and 13. For example, the communication device 140 may be the first host node or a chip within the first host node. The communication device 140 may include units for performing the operations executed by the first host node in the method embodiments shown in Figures 9, 10, 11, 12, and 13. Each unit in the communication device 140 is responsible for implementing the operations executed by the first host node in the method embodiments shown in Figures 9, 10, 11, 12, and 13. The descriptions of each unit are as follows:

[0460] Processing unit 1402 is used to retain the configuration information of the backhaul link when the fourth condition is met; the backhaul link is the backhaul link between the relay node and the first host node.

[0461] The fourth condition includes:

[0462] The first host node receives a sixth message from the Access and Mobility Management Function (AMF) element, the sixth message indicating that the relay node is in an unlicensed state; and the relay node is connected to the first host node.

[0463] or,

[0464] The processing unit 1402 is used to delete the configuration information when the relay node disconnects from the first host node.

[0465] In one possible implementation, the device further includes:

[0466] The communication unit 1401 is used to receive the seventh information from the second host node and send the configuration information of the backhaul link to the relay node;

[0467] The seventh piece of information is used to indicate that the relay node is in an unauthorized state.

[0468] For the technical effects of any of the above designs and any possible implementation methods, please refer to the description of the technical effects of the methods corresponding to Figures 9, 10, 11, 12, and 13 above, which will not be repeated here.

[0469] Optionally, in the communication device described in any of the above designs and any possible embodiments:

[0470] In one implementation, the communication device is a communication equipment. When the communication device is a communication equipment, the communication unit can be a transceiver or an input / output interface; the processing unit can be at least one processor. Optionally, the transceiver can be a transceiver circuit. Optionally, the input / output interface can be an input / output circuit.

[0471] In another implementation, the communication device is a chip (system) or circuit used in a communication device. When the communication device is a chip (system) or circuit used in a communication device, the communication unit can be a communication interface (input / output interface), interface circuit, output circuit, input circuit, pin, or related circuit on the chip (system) or circuit; the processing unit can be at least one processor, processing circuit, or logic circuit.

[0472] According to embodiments of this application, the various units in the device shown in FIG14 can be individually or entirely merged into one or more other units, or some of the units can be further divided into multiple functionally smaller units. This achieves the same operation without affecting the technical effect of the embodiments of this application. The above units are based on logical function division. In practical applications, the function of one unit can also be implemented by multiple units, or the function of multiple units can be implemented by one unit. In other embodiments of this application, the electronic device may also include other units. In practical applications, these functions can also be implemented with the assistance of other units, and can be implemented collaboratively by multiple units.

[0473] It should be noted that the implementation of each unit can also refer to the corresponding descriptions of the method embodiments shown in Figures 9, 10, 11, 12, and 13 above.

[0474] In the communication device 140 described in Figure 14, the IAB node can promptly release unused backhaul link configurations or save received backhaul link configurations for establishing backhaul links. This prevents the IAB node from having two conflicting backhaul link configurations and also saves signaling overhead.

[0475] Please refer to Figure 15, which is a schematic diagram of the structure of a communication device provided in an embodiment of this application.

[0476] It should be understood that the communication device 150 shown in FIG15 is only an example. The communication device in the embodiments of this application may also include other components, or include components with functions similar to the various components in FIG15, or may not be intended to include all the components in FIG15.

[0477] The communication device 150 includes a communication interface 1501 and at least one processor 1502.

[0478] The communication device 150 can correspond to any one of the first host node, relay node, third host node, and fourth host node. The communication interface 1501 is used for sending and receiving signals, and at least one processor 1502 executes program instructions, causing the communication device 150 to implement the corresponding flow of the method executed by the corresponding device in the above method embodiments.

[0479] In one possible design, the communication device 150 may correspond to the first host node in the method embodiments shown in Figures 9, 10, 11, 12, and 13. For example, the communication device 150 may be the first host node or a chip within the first host node. The communication device 150 may include components for performing the operations executed by the first host node in the above method embodiments, and each component in the communication device 150 is specifically designed to implement the operations performed by the first host node in the above method embodiments. Specifically, it may be as follows:

[0480] Processing unit 1402 is used to release the configuration of the backhaul link when a first triggering condition is met; the backhaul link is the backhaul link between the relay node and the first host node.

[0481] The first triggering condition includes:

[0482] The relay node performs mobile terminal (MT) migration; and, the relay node is in an unauthorized state; and, the relay node receives first configuration information from the first host node, the first configuration information being used to indicate the configuration of the backhaul link.

[0483] or,

[0484] The processor 1502 is used to save the third configuration information of the backhaul link when the relay node meets the fourth triggering condition; the backhaul link is the backhaul link between the relay node and the first host node.

[0485] The fourth triggering condition includes:

[0486] The relay node performs MT migration; and, the relay node is in an unauthorized state; and, the relay node receives the third configuration information from the first host node, the third configuration information being used to indicate the configuration information of the backhaul link.

[0487] In one possible implementation, the device further includes:

[0488] Communication interface 1501 is used to receive second configuration information from the first host node.

[0489] or,

[0490] The communication interface 1501 is used to receive second configuration information from the first host node when the relay node switches to the authorized state.

[0491] or,

[0492] Communication interface 1501 is used to send second information to the first host node, the second information being used to request at least one IP address.

[0493] or,

[0494] Communication interface 1501 is used for the relay node to send third information to the first host node when the second triggering condition is met, the third information being used to request an IP address;

[0495] The second triggering condition includes at least one of the following:

[0496] The second configuration information includes a default BAP configuration; or, the second configuration information includes a BAP address; or, the relay node receives fourth information, which is used to indicate that the relay node is in an authorized state.

[0497] or,

[0498] Communication interface 1501 is used to receive fifth information, which indicates that the relay node is in an authorized state; the relay node performs backhaul link transmission based on the configuration information.

[0499] In one possible design, the communication device 150 may correspond to the first host node in the method embodiments shown in Figures 9, 10, 11, 12, and 13. For example, the communication device 150 may be the first host node or a chip within the first host node. The communication device 150 may include units for performing the operations executed by the first host node in the method embodiments shown in Figures 9, 10, 11, 12, and 13. Each unit in the communication device 150 is responsible for implementing the operations executed by the first host node in the method embodiments shown in Figures 9, 10, 11, 12, and 13. The descriptions of each unit are as follows:

[0500] Processor 1502 is used to retain the configuration information of the backhaul link when the fourth condition is met; the backhaul link is the backhaul link between the relay node and the first host node.

[0501] The fourth condition includes:

[0502] The first host node receives a sixth message from the Access and Mobility Management Function (AMF) element, the sixth message indicating that the relay node is in an unlicensed state; and the relay node is connected to the first host node.

[0503] or,

[0504] Processor 1502 is configured to delete the configuration information when the relay node disconnects from the first host node.

[0505] In one possible implementation, the device further includes:

[0506] Communication interface 1501 is used to receive the seventh information from the second host node and send backhaul link configuration information to the relay node;

[0507] The seventh piece of information is used to indicate that the relay node is in an unauthorized state.

[0508] The methods executed by the processor 1502 and the communication interface 1501 can be referred to the methods corresponding to Figures 9, 10, 11, 12 and 13 above, and will not be repeated here.

[0509] For the technical effects of any of the above designs and any possible implementation methods, please refer to the description of the technical effects of the methods corresponding to Figures 9, 10, 11, 12, and 13 above, which will not be repeated here.

[0510] In the communication device 140 described in Figure 14, the IAB node can promptly release unused backhaul link configurations or save received backhaul link configurations for establishing backhaul links. This prevents the IAB node from having two conflicting backhaul link configurations and also saves signaling overhead.

[0511] It should be understood that when the communication device 150 is a relay node / first host node, it includes a CU and a DU. The CU may include a communication interface, a processor, and optionally a memory. The communication interface can be used to communicate with the CU of the host node or the DU of the IAB node. The DU may also include a communication interface, a processor, and a memory, as well as a bus connecting the communication interface, the processor, and the memory. The communication interface is used to communicate with the MT of the IAB node.

[0512] For cases where the communication device can be a chip or a chip system, please refer to the schematic diagram of the chip structure shown in Figure 16.

[0513] As shown in Figure 16, chip 160 includes processor 1601 and interface 1602. The number of processors 1601 can be one or more, and the number of interfaces 1602 can be multiple. It should be noted that the functions of processor 1601 and interface 1602 can be implemented through hardware design, software design, or a combination of both; no restrictions are placed here.

[0514] Optionally, chip 160 may also include memory 1603, which is used to store necessary program instructions and data.

[0515] In this application, processor 1601 can be used to call the implementation program of the communication method provided by one or more embodiments of this application from memory 1603, in one or more devices or nodes, including a first host node, a second host node, and a first node, and execute the instructions contained in the program. Interface 1602 can be used to output the execution result of processor 1601. In this application, interface 1602 can be specifically used to output various messages or information from processor 1601.

[0516] The communication methods provided by one or more embodiments of this application can be referred to the various embodiments shown in Figures 9, 10, 11, 12, and 13 above, and will not be repeated here.

[0517] The processor in this embodiment can be a Central Processing Unit (CPU), but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0518] The memory in this application embodiment is used to provide storage space, in which data such as operating system and computer programs can be stored. The memory includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), or compact disc read-only memory (CD-ROM).

[0519] According to the method provided in the embodiments of this application, the embodiments of this application also provide a computer-readable storage medium storing a computer program. When the computer program is run on one or more processors, it can implement the methods shown in Figures 9, 10, 11, 12, and 13.

[0520] According to the method provided in the embodiments of this application, the embodiments of this application also provide a computer program product, which includes a computer program. When the computer program runs on a processor, it can implement the methods shown in Figures 9, 10, 11, 12, and 13.

[0521] This application also provides a system comprising at least one communication device 140, 150, or chip 160 as described above, for performing the steps executed by the corresponding device in any of the embodiments of Figures 9, 10, 11, 12, and 13.

[0522] This application also provides a system comprising at least one of a relay node, a first host node, a second host node, and an AMF server. The relay node is used to execute the steps executed by the relay node in any of the embodiments of Figures 9, 10, 11, 12, and 13. The first host node is used to execute the steps executed by the first host node in any of the embodiments of Figures 9, 10, 11, 12, and 13. The second host node is used to execute the steps executed by the relay node in any of the embodiments of Figures 12 and 13. The AMF server is used to execute the steps executed by the third host node in any of the embodiments of Figures 9, 10, 11, 12, and 13.

[0523] This application also provides a processing apparatus, including a processor and an interface; the processor is used to execute the method in any of the above method embodiments.

[0524] It should be understood that the aforementioned processing device can be a chip. For example, the processing device can be a field-programmable gate array (FPGA), a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf FPGA, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, a system-on-chip (SoC), a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD), or other integrated chips. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software module can reside in a mature storage medium in the field, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0525] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0526] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0527] The units in the above-described device embodiments and the electronic devices in the method embodiments completely correspond to each other, with corresponding modules or units performing corresponding steps. For example, the communication unit (transceiver) performs the receiving or sending steps in the method embodiments, while other steps besides sending and receiving can be performed by the processing unit (processor). The functions of specific units can be found in the corresponding method embodiments. There can be one or more processors.

[0528] It is understood that in the embodiments of this application, the electronic device may perform some or all of the steps in the embodiments of this application. These steps or operations are merely examples, and the embodiments of this application may also perform other operations or variations thereof. Furthermore, the steps may be performed in different orders as presented in the embodiments of this application, and it is not necessarily necessary to perform all the operations in the embodiments of this application.

[0529] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0530] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0531] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0532] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0533] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0534] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the contributing part, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0535] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A communication method, characterized in that, The method includes: When the first triggering condition is met, the relay node releases the configuration of the backhaul link; the backhaul link is the backhaul link between the relay node and the first host node. The first triggering condition includes: The relay node performs mobile terminal (MT) migration; and, the relay node is in an unauthorized state; and, the relay node receives first configuration information from the first host node, the first configuration information being used to indicate the configuration of the backhaul link.

2. The method according to claim 1, characterized in that, The first configuration information includes at least one of the following: The default Backhaul Link Adaptor Layer (BAP) configuration, BAP address, and Internet Protocol (IP) address.

3. The method according to claim 1 or 2, characterized in that, The method further includes: When the relay node switches to authorized state, it receives second configuration information from the first host node, the second configuration information being used to indicate the configuration of the backhaul link.

4. The method according to claim 3, characterized in that, The second configuration information includes an IP address.

5. The method according to claim 4, characterized in that, The IP address is used for the control plane protocol F1-C.

6. The method according to any one of claims 3-5, characterized in that, The method further includes: The relay node sends a second message to the first host node, the second message being used to request at least one IP address.

7. The method according to claim 3, characterized in that, The second configuration information does not include an IP address; the method further includes: When the second triggering condition is met, the relay node sends third information to the first host node, the third information being used to request an IP address; The second triggering condition includes at least one of the following: The second configuration information includes a default BAP configuration; or, the second configuration information includes a BAP address; or, the relay node receives fourth information, which is used to indicate that the relay node is in an authorized state.

8. The method according to claim 7, characterized in that, The fourth piece of information comes from the non-access layer NAS or access layer AS of the relay node.

9. A communication method, characterized in that, The method includes: When the fourth triggering condition is met, the relay node saves the third configuration information of the backhaul link; the backhaul link is the backhaul link between the relay node and the first host node. The fourth triggering condition includes: The relay node performs MT migration; and, the relay node is in an unauthorized state; and, the relay node receives the third configuration information from the first host node, the third configuration information being used to indicate the configuration information of the backhaul link.

10. The method according to claim 9, characterized in that, The method further includes: The relay node receives a fifth piece of information, which indicates that the relay node is in an authorized state; the relay node performs backhaul link transmission based on the configuration information.

11. A communication method, characterized in that, The method includes: If the fourth condition is met, the first host node retains the configuration information of the backhaul link; the backhaul link is the backhaul link between the relay node and the first host node. The fourth condition includes: The first host node receives a sixth message from the Access and Mobility Management Function (AMF) element, the sixth message indicating that the relay node is in an unlicensed state; and the relay node is connected to the first host node.

12. The method according to claim 11, characterized in that, The method further includes: The first host node receives the seventh information from the second host node and sends the backhaul link configuration information to the relay node; The seventh piece of information is used to indicate that the relay node is in an unauthorized state.

13. The method according to claim 11 or 12, characterized in that, The method further includes: If the relay node disconnects from the first host node, the configuration information is deleted.

14. A communication device, characterized in that, Includes units for performing the method as described in any one of claims 1 to 13.

15. A communication device, characterized in that, Includes a processor for performing the method as described in any one of claims 1 to 13.

16. A communication device, characterized in that, It includes logic circuits and interfaces, wherein the logic circuits and the interfaces are coupled; The interface is used for inputting and / or outputting information, and the logic circuit is used for performing the method as described in any one of claims 1 to 13.

17. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store a computer program, which, when executed, performs the method as described in any one of claims 1 to 13.

18. A communication system, characterized in that, include: Relay node, first host node; The relay node is used to perform the method as described in any one of claims 1 to 10, and the first host node is used to perform the method as described in any one of claims 11 to 13.

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