Communication method, communication apparatus, chip, computer readable storage medium, and computer program product

Abstract

The present application discloses a communication method, a communication apparatus, a chip, a computer readable storage medium, and a computer program product. The method is applied to a relay node, and comprises: when a trigger condition is satisfied, determining whether to maintain a first interface, the first interface being an interface between a relay node and an access network device, or the first interface being an interface between the relay node and a source host node of the relay node, and the trigger condition comprising at least one of the following: a mobile terminal (MT) of the relay node is to hand over, the MT has handed over to a target host node of the relay node, or radio resource control (RRC) reestablishment of the MT under the target host node has been completed; and when it is determined that the first interface is to be maintained, sending configuration update information to the access network device or the source host node, the configuration update information comprising an Internet protocol (IP) address of the relay node under the target host node. The present application provides a maintenance scheme of an interface between a relay node and an access network device.

Description

Communication method, communication device, chip, computer-readable storage medium, and computer program product

[0001] This application claims priority to the Chinese patent application with application number 202410381882.4 filed with the State Intellectual Property Office of China on March 28, 2024, and priority to the Chinese patent application with the invention name “Communication method, communication device, chip, computer-readable storage medium and computer program product”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and in particular to a communication method, a communication device, a chip, a computer-readable storage medium, and a computer program product. Background Art

[0003] The 3rd Generation Partnership Project (3GPP) is exploring wireless access and backhaul (WAB) architectures (or networks) within the topology enhancements section of Rel-19, a communication protocol release. This research could be applied to vehicle-mounted mobile relay (VMR) scenarios. In VMR scenarios, relay nodes can be deployed in vehicles (or even aircraft) to provide wireless coverage for user equipment (UE) inside the vehicle, overcoming poor wireless signal conditions inside the vehicle. Relay nodes connect to macro base stations (host node base stations, also known as donors) via wireless backhaul.

[0004] The relay node in Release 19 is currently named the WAB node. The WAB node includes the base station (gNB) function (i.e., WAB-gNB) and the mobile terminal (MT) function (i.e., WAB-MT). In the WAB architecture, the UE accesses the WAB-gNB through the Uu port. The WAB-MT then wraps the UE's data in its own protocol data unit (PDU) session and sends it through the WAB-MT's Uu port, through the WAB-MT's host node (or host base station), to the WAB-MT's user plane function (UPF) network element. The WAB-MT's UPF network element then removes the WAB-MT-related packet header information, revealing the UE-related packet header information, and sends it to the UE's UPF network element according to the Internet Protocol (IP) routing. Logically, a PDU session is also established between the UE and the UE's UPF network element, but this is wrapped in the WAB-MT's PDU session for transmission.

[0005] In a VMR scenario, the relay node is mobile, and the mobile operator (e.g., WAB-MT) of the relay node may undergo cross-host node handover (i.e., switching from the source host node to the target host node) and cross-host node radio resource control (RRC) re-establishment (i.e., disconnecting the RRC connection with the source host node and then re-establishing the RRC connection with the target host node). The prior art does not provide a solution for maintaining the interface between the relay node and the access network device after a cross-host node handover or cross-host node RRC re-establishment of the mobile operator (e.g., WAB-MT) of the relay node occurs. Summary of the Invention

[0006] The embodiments of the present application disclose a communication method, a communication device, a chip, a computer-readable storage medium, and a computer program product; they can solve the problem of whether the interface between the relay node and the access network device needs to be maintained and how to maintain it after the MT of the relay node (e.g., WAB-MT) undergoes cross-host node switching or cross-host node RRC re-establishment.

[0007] In a first aspect, an embodiment of the present application provides a communication method, applied to a relay node, comprising: determining whether to maintain a first interface when a trigger condition is met, the first interface being an interface between the relay node and an access network device, or the first interface being an interface between the relay node and its source host node, the trigger condition comprising at least one of the following: a mobile terminal (MT) of the relay node is about to be handed over, the MT has handed over to a target host node of the relay node, or radio resource control (RRC) re-establishment of the MT at the target host node is complete; and when determining to maintain the first interface, sending configuration update information to the access network device or the source host node, the configuration update information including the Internet Protocol (IP) address of the relay node at the target host node. The configuration update information is used to maintain the first interface. Alternatively, the configuration update information is used by the access network device or the source host node to maintain the first interface. The relay node may include base station functionality (e.g., gNB functionality) and MT functionality, for example, the relay node includes complete base station functionality. The relay node may have a layer 3 architecture. The relay node may be any node having base station functions and MT functions, such as a WAB node, which is not limited in this application. The access network device does not include the source host node.

[0008] In an embodiment of the present application, a relay node determines whether to maintain a first interface, and when determining to maintain the first interface, sends configuration update information to an access network device or a source host node so that the access network device or the source host node can maintain the first interface; thereby providing an interface maintenance solution between a relay node and an access network device. In addition, by maintaining the first interface, the target host node can subsequently forward data to an access network device (e.g., a base station) having an Xn interface with the relay node via an IP network on the radio access network (RAN) side, without having to forward the data to a core network and then to other access network devices via the core network; thereby improving transmission efficiency.

[0009] In a possible implementation, the method further includes: when determining to remove the first interface, initiating a process of removing the first interface. In the present application, determining to remove the first interface may be replaced by determining not to maintain the first interface.

[0010] In this implementation, when it is determined to remove the first interface, a process of removing the first interface is initiated, thereby avoiding resource overhead caused by maintaining the first interface.

[0011] In a possible implementation manner, the relay node includes a base station function and an MT function, and the first interface is an Xn interface.

[0012] In a possible implementation manner, the configuration update information further includes identification information of the relay node and / or the IP address of the relay node under the source host node.

[0013] In this implementation, the node receiving the configuration update information may index the relay node corresponding to the new configuration information based on the identification information of the relay node and / or the IP address of the relay node under the source host node.

[0014] In one possible implementation, the first interface is an interface between the relay node and the access network device; the determining whether to maintain the first interface includes: when the relay node and the access network device cannot communicate via IP routing, determining to remove the first interface; otherwise, determining to maintain the first interface; or, when the benefit value of the interface between the relay node and the access network device is greater than or equal to a preset threshold, determining to maintain the first interface; otherwise, determining to remove the first interface. The preset threshold can be set according to actual needs and is not limited in this application.

[0015] In this implementation, when IP routing is no longer possible between the relay node and the access network device, the first interface is removed, thereby reducing the resource overhead associated with maintaining the first interface. When the benefit of the interface between the relay node and the access network device is greater than or equal to a preset threshold, the first interface is maintained, thereby enabling subsequent data transmission via the first interface to achieve better communication gain.

[0016] In one possible implementation, the first interface is the interface between the relay node and its source host node; the determination of whether to maintain the first interface includes: when the relay node and the source host node cannot communicate through IP routing, determining to remove the first interface; otherwise, determining to maintain the first interface; and / or, when the benefit value of the interface between the relay node and the source host node is higher than or equal to a preset threshold, determining to maintain the first interface; otherwise, determining to remove the first interface.

[0017] In this implementation, when the relay node and the source host node are unable to communicate via IP routing, the first interface is removed, thereby saving resource overhead associated with maintaining the first interface. When the benefit value of the interface between the relay node and the source host node is greater than or equal to a preset threshold, the first interface is maintained, thereby enabling better communication gain for subsequent data transmission via the first interface.

[0018] In a second aspect, an embodiment of the present application provides another communication method, which is applied to a relay node, and the method includes: determining that a trigger condition is met, and the trigger condition includes at least one of the following: the MT of the relay node is about to be switched, the MT has been switched to the target host node of the relay node, or the RRC re-establishment of the MT under the target host node is completed; initiating a process of removing a first interface or sending a first removal indication message to an access network device or sending a second removal indication message to the source host node of the relay node, the first interface being the interface between the relay node and the access network device, or the first interface being the interface between the relay node and its source host node, the first removal indication message is used to instruct the access network device to remove the interface between the relay node and the relay node, and the second removal indication message is used to instruct the source host node to remove the interface between the relay node and the relay node. Exemplarily, when it is determined that the trigger condition is met, initiating a process of removing the first interface or sending a first removal indication message to the access network device or sending a second removal indication message to the source host node of the relay node.

[0019] In an embodiment of the present application, when it is determined that the trigger condition is met, the process of removing the first interface is initiated or a first removal indication message is sent to the access network device or a second removal indication message is sent to the source host node of the relay node; the resource overhead brought by maintaining the first interface can be avoided.

[0020] In one possible implementation, the first removal indication information includes the identification information of the relay node or the IP address of the relay node under the source host node, and / or the second removal indication information includes the identification information of the relay node or the IP address of the relay node under the source host node.

[0021] In this implementation, the first removal indication information includes the identification information of the relay node or the IP address of the relay node under the source host node, so that the access network device knows that it needs to maintain the interface with the relay node. The second removal indication information includes the identification information of the relay node or the IP address of the relay node under the source host node, so that the access network device knows that it needs to maintain the interface with the relay node.

[0022] In a possible implementation manner, the relay node includes a base station function and an MT function, and the first interface is an Xn interface.

[0023] In a third aspect, embodiments of the present application provide another communication method, which is applied to a relay node, a source host node of the relay node, or a target host node of the relay node. The method includes: determining that a trigger condition is satisfied, wherein the trigger condition includes at least one of the following: the mobile terminal of the relay node is about to be handed over, the mobile terminal has been handed over to the target host node, the mobile terminal is in the process of re-establishing RRC, or the mobile terminal has completed RRC re-establishment under the target host node; and sending a first message to an access network device, wherein the first message includes configuration update information and / or identification information of the target host node, wherein the configuration update information includes the IP address of the relay node under the target host node. Exemplarily, when the trigger condition is determined to be satisfied, the first message is sent to the access network device. The configuration update information and / or identification information of the target host node are used to determine whether the interface between the relay node and the access network device needs to be maintained. In other words, the configuration update information and / or identification information of the target host node are used by the access network device to determine whether to maintain the interface with the relay node.

[0024] In an embodiment of the present application, when it is determined that the trigger condition is met, a first message is sent to the access network device; so that the access network device determines whether to maintain the interface with the relay node based on the configuration update information and / or the identification information of the target host node.

[0025] In one possible implementation, the first message does not include the configuration update information; the method further includes: when no third removal indication information is received within a first preset time period after sending the first message to the access network device, sending the configuration update information to the access network device, wherein the third removal indication information is used to instruct the relay node to remove the interface between the relay node and the access network device. The execution entity of the method may be a relay node. The first preset time period can be set according to actual needs and is not limited by this application.

[0026] In this implementation, the first message does not include configuration update information, thereby reducing the amount of data carried by the first message. If the third removal indication message is not received within a first preset time period after the first message is sent to the access network device, configuration update information is sent to the access network device to enable the access network device to maintain the interface with the relay node.

[0027] In one possible implementation, the first message does not include the configuration update information; the method further includes: upon receiving third removal indication information within a first preset time period after sending the first message to the access network device, initiating a process for removing the interface with the access network device. The method may be performed by a relay node.

[0028] In this implementation, the first message does not include configuration update information, which can save the amount of data carried by the first message.

[0029] In a possible implementation manner, the configuration update information further includes identification information of the relay node and / or the IP address of the relay node under the source host node.

[0030] In this implementation, the node receiving the configuration update information may index the relay node corresponding to the new configuration information based on the identification information of the relay node and / or the IP address of the relay node under the source host node.

[0031] In a fourth aspect, embodiments of the present application provide another communication method, applied to a relay node, a source host node of the relay node, or a target host node of the relay node. The method comprises: determining that a trigger condition is satisfied, the trigger condition comprising at least one of the following: the mobile terminal of the relay node is about to be handed over, the mobile terminal has already been handed over to the target host node, the mobile terminal is in the process of performing an RRC re-establishment, or the mobile terminal has completed RRC re-establishment under the target host node; and, if no third removal indication information is received within a second preset time period after determining that the trigger condition is satisfied, sending configuration update information to an access network device, the configuration update information including the IP address of the relay node under the target host node, the third removal indication information being used to instruct the relay node to remove the interface between the relay node and the access network device. The configuration update information is used by the access network device to maintain the interface between the relay node and the relay node. The second preset time period can be set according to actual needs and is not limited by this application. Optionally, if the third removal indication information is received within the second preset time period after determining that the trigger condition is satisfied, sending the configuration update information to the access network device is not required.

[0032] In an embodiment of the present application, when the third removal indication information is not received within the second preset time period after determining that the trigger condition is met, configuration update information is sent to the access network device; this allows the access network device to maintain the interface with the relay node.

[0033] In a possible implementation manner, the configuration update information further includes identification information of the relay node and / or the IP address of the relay node under the source host node.

[0034] In this implementation, the node receiving the configuration update information may index the relay node corresponding to the new configuration information based on the identification information of the relay node and / or the IP address of the relay node under the source host node.

[0035] In one possible implementation, the method further includes: when determining that the trigger condition is met, sending a first message to the access network device, the first message including identification information of the target host node. The first message is used by the access network device to determine whether to maintain the interface with the relay node.

[0036] In this implementation, when it is determined that the trigger condition is met, a first message is sent to the access network device, so that the access network device determines whether to maintain the interface with the relay node based on the first message.

[0037] In a possible implementation, the relay node includes a base station function and an MT function, and the interface between the relay node and the access network device is an Xn interface.

[0038] In a fifth aspect, embodiments of the present application provide another communication method, applied to an access network device, comprising: receiving a first message, the first message including configuration update information and / or identification information of a target host node of a relay node, the configuration update information including the IP address of the relay node under the target host node; and determining, based on the first message, whether to maintain an interface with the relay node. The configuration update information is used to maintain the interface between the relay node and the access network device.

[0039] In an embodiment of the present application, the access network device determines whether to maintain the interface with the relay node based on the first message, so as to subsequently remove or maintain the interface with the relay node.

[0040] In a possible implementation manner, the configuration update information further includes identification information of the relay node and / or the IP address of the relay node under the source host node.

[0041] In this implementation, the node receiving the configuration update information may index the relay node corresponding to the new configuration information based on the identification information of the relay node and / or the IP address of the relay node under the source host node.

[0042] In a possible implementation, the first message does not include the configuration update information; the method further includes: when determining to maintain the interface with the relay node based on the first message, receiving the configuration update information from the relay node.

[0043] In this implementation, the first message does not include configuration update information, which can reduce the amount of data carried by the first message. When determining to maintain the interface with the relay node based on the first message, configuration update information is received from the relay node; the interface with the relay node can be maintained based on the configuration update information.

[0044] In a possible implementation, the method further includes: when determining to maintain the interface with the relay node, updating the IP address of the relay node maintained by the relay node to the IP address of the relay node under the target host node.

[0045] In this implementation, the IP address of the relay node maintained by itself is updated to the IP address of the relay node under the target host node, so that subsequent data transmission between the relay node and the access network device can be carried out through the IP address.

[0046] In a possible implementation manner, the method further includes: when it is determined to remove the interface with the relay node, initiating a process of removing the interface with the relay node.

[0047] In this implementation, initiating a process of removing the interface with the relay node can save the overhead of maintaining the interface.

[0048] In a possible implementation, the method further includes: when determining to remove the interface between the relay node and the relay node, sending third removal indication information to the relay node, where the third removal indication information is used to instruct the relay node to remove the interface between the relay node and the access network device.

[0049] In this implementation, the third removal indication information is sent to the relay node so as to remove the interface with the relay node, thereby saving the overhead of maintaining the interface.

[0050] In one possible implementation, the first message includes the configuration update information; and determining whether to maintain the interface with the relay node based on the first message includes: when the benefit value of the interface between the access network device and the relay node is higher than or equal to a preset threshold, determining to maintain the interface with the relay node; otherwise, determining to remove the interface with the relay node.

[0051] In this implementation, when the benefit value of the interface between the access network device and the relay node is higher than or equal to a preset threshold, it is determined to maintain the interface with the relay node; so that subsequent data transmission through the interface with the relay node brings better communication gain.

[0052] In one possible implementation, the first message includes identification information of the target host node of the relay node; determining whether to maintain the interface with the relay node based on the first message includes: when the access network device and the target host node cannot communicate through IP routing, determining to remove the interface with the relay node; otherwise, determining to maintain the interface with the relay node.

[0053] In this implementation, when the access network device and the target host node cannot communicate via IP routing, the interface between the access network device and the relay node is removed, thereby saving the resource overhead of maintaining the interface. When the access network device and the target host node can communicate via IP routing, the interface between the access network device and the relay node is maintained to facilitate subsequent data transmission via the interface between the access network device and the relay node.

[0054] In a sixth aspect, an embodiment of the present application provides another communication method, which is applied to a source host node or a target host node of a relay node, the method comprising: determining that a trigger condition is satisfied, the trigger condition comprising at least one of the following: the mobile equipment (MT) of the relay node is about to be switched, the MT has been switched to the target host node, the MT is performing RRC re-establishment, or the RRC re-establishment of the MT under the target host node is completed; and sending first removal indication information to an access network device, the first removal indication information being used to instruct the access network device to remove the interface between the access network device and the relay node. Exemplarily, when it is determined that the trigger condition is satisfied, the first removal indication information is sent to the access network device.

[0055] In the embodiment of the present application, when it is determined that the trigger condition is met, first removal indication information is sent to the access network device, thereby avoiding the resource overhead caused by maintaining the Xn interface.

[0056] In a possible implementation, the first removal indication information includes identification information of the relay node or the IP address of the relay node under the source host node.

[0057] In a seventh aspect, an embodiment of the present application provides another communication method, which is applied to a source host node or a target host node of a relay node, the method comprising: determining that a trigger condition is satisfied, the trigger condition comprising at least one of the following: the mobile operator (MT) of the relay node is about to be switched, the MT has been switched to the target host node, the MT is performing RRC re-establishment, or the RRC re-establishment of the MT under the target host node is complete; and sending third removal indication information to the relay node, the third removal indication information being used to instruct the relay node to remove the interface between the relay node and the access network device. Exemplarily, when it is determined that the trigger condition is satisfied, the third removal indication information is sent to the relay node.

[0058] In this embodiment of the present application, when the trigger condition is determined to be met, a third removal instruction message is sent to the relay node. In other words, when the trigger condition is determined to be met, the relay node is directly instructed to remove the interface between the relay node and the access network device, thereby avoiding the resource overhead caused by maintaining the Xn interface.

[0059] In a possible implementation manner, the third removal indication information includes identification information of the access network device or the IP address of the access network device.

[0060] In an eighth aspect, an embodiment of the present application provides another communication method, which is applied to a target host node of a relay node, and the method includes: determining whether the interface between the relay node and the access network device needs maintenance; when it is determined that the interface between the relay node and the access network device needs maintenance, sending maintenance indication information to the relay node, and / or sending configuration update information to the access network device, the maintenance indication information is used to instruct the relay node to maintain the interface with the access network device, and the configuration update information includes the IP address of the relay node under the target host node. The configuration update information is used for the maintenance of the interface between the relay node and the access network device. In other words, the configuration update information is used by the access network device to maintain the interface between the access network device and the relay node.

[0061] In an embodiment of the present application, when it is determined that the interface between the relay node and the access network device needs maintenance, maintenance indication information is sent to the relay node, and / or configuration update information is sent to the access network device to maintain the interface between the relay node and the access network device; the problem of how to maintain the interface between the relay node and the access network device can be solved.

[0062] In a possible implementation manner, the configuration update information further includes identification information of the relay node and / or the IP address of the relay node under the source host node.

[0063] In this implementation, the node receiving the configuration update information may index the relay node corresponding to the new configuration information based on the identification information of the relay node and / or the IP address of the relay node under the source host node.

[0064] In one possible implementation, the method further includes: when it is determined that the interface between the relay node and the access network device needs to be removed, sending fourth removal indication information to the relay node, and / or sending first removal indication information to the access network device, the fourth removal indication information is used to instruct the relay node to remove the interface between it and the access network device, and the first removal indication information is used to instruct the access network device to remove the interface between it and the relay node.

[0065] In this implementation, the fourth removal indication information is sent to the relay node, and / or the first removal indication information is sent to the access network device; thus, resource overhead for maintaining the interface between the relay node and the access network device can be saved.

[0066] In one possible implementation, the method further includes: receiving a second message from the relay node or the source host node of the relay node, the second message including identification information of the access network device. Optionally, the second message also includes information indicating that the access network device has an interface with the relay node. Receiving the second message from the relay node or the source host node of the relay node can be a trigger condition for determining whether the interface between the relay node and the access network device requires maintenance. In other words, the second message is used to trigger the target host node to determine whether the interface between the relay node and the access network device requires maintenance.

[0067] In this implementation, by receiving the second message from the relay node or the source host node of the relay node, the target host node can obtain the identification information of the access network device.

[0068] In one possible implementation, the second message comes from the source host node, and the second message is a handover request message or a UE context retrieval response message, the handover request message is used to request that the MT of the relay node be handed over to the target host node, and the UE context retrieval response message carries the context of the MT; or, the second message comes from the relay node, and the second message is an RRC message or an Xn interface application protocol process (Xn application protocol, XnAP) message.

[0069] In this implementation, the second message can reuse an existing message, which can save signaling overhead.

[0070] In one possible implementation, determining whether the interface between the relay node and the access network device needs maintenance includes: determining whether the interface between the relay node and the access network device needs maintenance based on whether the target host node and the access network device can communicate through IP routing; or, determining whether the interface between the relay node and the access network device needs maintenance based on whether there is an interface between the target host node and the access network device; or, determining whether the interface between the relay node and the access network device needs maintenance based on the benefit value of the interface between the target host node and the access network device.

[0071] In this implementation, it is possible to reasonably determine whether the interface between the relay node and the access network device requires maintenance. When these methods determine that the interface between the relay node and the access network device requires maintenance, in some cases, the relay node and the access network device may communicate better using this interface than using other methods.

[0072] In a ninth aspect, an embodiment of the present application provides another communication method, which is applied to a relay node, and the method includes: receiving maintenance indication information from a target host node of the relay node, the maintenance indication information is used to instruct the relay node to maintain the interface between the relay node and the access network device; sending configuration update information to the access network device, the configuration update information includes the IP address of the relay node under the target host node. The configuration update information is used for the maintenance of the interface between the relay node and the access network device. The configuration update information is used for the maintenance of the interface between the relay node and the access network device. Exemplarily, in response to the maintenance indication information, configuration update information is sent to the access network device.

[0073] In an embodiment of the present application, configuration update information is sent to the access network device so that the access network device maintains the interface with the relay node.

[0074] In a possible implementation manner, the configuration update information further includes identification information of the relay node and / or the IP address of the relay node under the source host node.

[0075] In this implementation, the node receiving the configuration update information may index the relay node corresponding to the new configuration information based on the identification information of the relay node and / or the IP address of the relay node under the source host node.

[0076] In a possible implementation manner, the maintenance instruction information includes identification information of the access network device or the IP address of the access network device.

[0077] In this implementation, the maintenance indication information includes identification information of the access network device or the IP address of the access network device, so that the relay node sends configuration update information to the access network device.

[0078] In a possible implementation manner, the method further includes: sending a second message to a source host node of the relay node or the target host node, where the second message includes identification information of the access network device.

[0079] In this implementation, the source host node or the target host node may determine whether to maintain the interface between the relay node and the access network device.

[0080] In the tenth aspect, an embodiment of the present application provides another communication method, which is applied to a relay node, and the method includes: receiving a fourth removal indication information from a target host node of the relay node, the fourth removal indication information being used to instruct the relay node to remove the interface between the relay node and the access network device; in response to the fourth removal indication information, initiating a process of removing the interface between the relay node and the access network device.

[0081] In this embodiment of the present application, in response to the fourth removal instruction information, a process for removing the interface between the relay node and the access network device is initiated, thereby saving resource overhead for maintaining the interface. Receiving the fourth removal instruction information from the target host node of the relay node can be replaced by receiving the fourth removal instruction information from the source host node of the relay node.

[0082] In a possible implementation manner, the fourth removal indication information includes identification information of the access network device or the IP address of the access network device.

[0083] In a possible implementation manner, the method further includes: sending a second message to a source host node of the relay node or the target host node, where the second message includes identification information of the access network device.

[0084] In this implementation, the source host node or the target host node may determine whether to maintain the interface between the relay node and the access network device.

[0085] In the eleventh aspect, an embodiment of the present application provides another communication method, which is applied to an access network device, the method comprising: receiving a first removal indication message from a target host node of a relay node, the first removal indication message being used to instruct the access network device to remove the interface between the access network device and the relay node; in response to the first removal indication message, initiating a process of removing the interface between the access network device and the relay node.

[0086] In the embodiment of the present application, in response to the first removal indication information, a process of removing the interface between the relay node is initiated; thus, resource overhead for maintaining the interface can be saved.

[0087] In a possible implementation, the first removal indication information includes identification information of the relay node or the IP address of the relay node under the source host node.

[0088] In a twelfth aspect, an embodiment of the present application provides a communication device having the function of implementing the behavior in the method embodiment of the first aspect above. The communication device can be a communication device, or a component of a communication device (such as a processor, a chip, or a chip system, etc.), or a logic module or software that can implement all or part of the functions of the communication device. The functions of the communication device can be implemented by hardware, or by hardware executing corresponding software implementations, and the hardware or software includes one or more modules or units corresponding to the above functions. In one possible implementation, the communication device includes a transceiver module and a processing module, wherein: the processing module is used to determine whether to maintain the first interface when a trigger condition is met, the first interface is the interface between the relay node and the access network device, or the first interface is the interface between the relay node and its source host node, and the trigger condition includes at least one of the following: the MT of the relay node is to be switched, the MT has been switched to the target host node of the relay node, or the RRC re-establishment of the MT under the target host node is completed; the transceiver module is used to send configuration update information to the access network device or the source host node when the processing module determines to maintain the first interface, and the configuration update information includes the IP address of the relay node under the target host node.

[0089] In a possible implementation manner, the configuration update information further includes identification information of the relay node and / or the IP address of the relay node under the source host node.

[0090] In this implementation, the node receiving the configuration update information may index the relay node corresponding to the new configuration information based on the identification information of the relay node and / or the IP address of the relay node under the source host node.

[0091] In a possible implementation, the processing module is further configured to initiate a process of removing the first interface when it is determined to remove the first interface.

[0092] In one possible implementation, the first interface is the interface between the relay node and the access network device; the processing module is specifically used to determine to remove the first interface when communication between the relay node and the access network device cannot be carried out through IP routing, otherwise, determine to maintain the first interface; and / or, when the benefit value of the interface between the relay node and the access network device is higher than or equal to a preset threshold, determine to maintain the first interface, otherwise, determine to remove the first interface.

[0093] In one possible implementation, the first interface is the interface between the relay node and its source host node; the processing module is specifically used to determine to remove the first interface when the relay node and the source host node cannot communicate through IP routing, otherwise, determine to maintain the first interface; and / or, when the benefit value of the interface between the relay node and the source host node is higher than or equal to a preset threshold, determine to maintain the first interface, otherwise, determine to remove the first interface.

[0094] Possible implementations of the communication method of the twelfth aspect can refer to the various possible implementations of the first aspect.

[0095] For the technical effects brought about by various possible implementation methods of the twelfth aspect, reference may be made to the introduction to the technical effects of the first aspect or various possible implementation methods of the first aspect.

[0096] In a thirteenth aspect, an embodiment of the present application provides another communication device, which has the function of implementing the behavior in the method embodiment of the second aspect above. The communication device can be a communication device, or it can be a component of a communication device (such as a processor, a chip, or a chip system, etc.), or it can be a logic module or software that can implement all or part of the functions of the communication device. The functions of the communication device can be implemented by hardware, or they can be implemented by hardware executing corresponding software, and the hardware or software includes one or more modules or units corresponding to the above functions. In one possible implementation, the communication device includes a transceiver module and a processing module, wherein: the processing module is used to determine whether a trigger condition is met, and the trigger condition includes at least one of the following: the MT of the relay node is to be switched, the MT has been switched to the target host node of the relay node, or the RRC re-establishment of the MT under the target host node is completed; the transceiver module is used to send removal interaction information (included in the process of initiating the removal of the first interface) to the access network device or send first removal indication information to the access network device or send second removal indication information to the source host node of the relay node, the first interface is the interface between the relay node and the access network device, or the first interface is the interface between the relay node and its source host node, the removal interaction information is used to remove the interface between the relay node and the access network device, the first removal indication information is used to instruct the access network device to remove the interface between the relay node and the relay node, and the second removal indication information is used to instruct the source host node to remove the interface between the relay node and the relay node.

[0097] For possible implementations of the communication method of the thirteenth aspect, reference may be made to various possible implementations of the second aspect.

[0098] For the technical effects brought about by various possible implementation methods of the thirteenth aspect, reference may be made to the introduction to the technical effects of the second aspect or various possible implementation methods of the second aspect.

[0099] In a fourteenth aspect, an embodiment of the present application provides another communication device, which has the function of implementing the behavior in the embodiment of the method of the third aspect above. The communication device can be a communication device, or a component of a communication device (such as a processor, a chip, or a chip system, etc.), or a logic module or software that can implement all or part of the functions of the communication device. The functions of the communication device can be implemented by hardware, or can be implemented by hardware executing corresponding software, and the hardware or software includes one or more modules or units corresponding to the above functions. In one possible implementation, the communication device includes a transceiver module and a processing module, wherein: the processing module is used to determine whether a trigger condition is met, and the trigger condition includes at least one of the following: the MT of the relay node is about to be switched, the MT has been switched to the target host node, the MT is performing RRC re-establishment, or the RRC re-establishment of the MT under the target host node is completed; the transceiver module is used to send a first message to the access network device, the first message including configuration update information and / or identification information of the target host node, and the configuration update information includes the IP address of the relay node under the target host node.

[0100] In one possible implementation, the first message does not include the configuration update information; the transceiver module is also used to send the configuration update information to the access network device when no third removal indication information is received within a first preset time period after sending the first message to the access network device, and the third removal indication information is used to instruct the relay node to remove the interface between it and the access network device.

[0101] In one possible implementation, the first message does not include the configuration update information; the transceiver module is further configured to initiate a process for removing the interface with the access network device upon receiving third removal indication information within a first preset time period after sending the first message to the access network device. The method may be performed by a relay node.

[0102] Possible implementations of the communication method of the fourteenth aspect can refer to the various possible implementations of the third aspect.

[0103] For the technical effects brought about by various possible implementation methods of the fourteenth aspect, reference may be made to the introduction to the technical effects of the third aspect or various possible implementation methods of the third aspect.

[0104] In a fifteenth aspect, an embodiment of the present application provides another communication device, which has the function of implementing the behavior in the method embodiment of the fourth aspect above. The communication device can be a communication device, or it can be a component of a communication device (such as a processor, a chip, or a chip system, etc.), or it can be a logic module or software that can implement all or part of the functions of the communication device. The functions of the communication device can be implemented by hardware, or they can be implemented by hardware executing corresponding software, and the hardware or software includes one or more modules or units corresponding to the above functions. In one possible implementation, the communication device includes a transceiver module and a processing module, wherein: the processing module is used to determine whether a trigger condition is met, and the trigger condition includes at least one of the following: the MT of the relay node is about to be switched, the MT has been switched to the target host node, the MT is performing RRC re-establishment, or the RRC re-establishment of the MT under the target host node is completed; the transceiver module is used to send configuration update information to the access network device when no third removal indication information is received within a second preset time after the processing module determines that the trigger condition is met, the configuration update information includes the IP address of the relay node under the target host node, and the third removal indication information is used to instruct the relay node to remove the interface between the relay node and the access network device.

[0105] In one possible implementation, the transceiver module is further configured to, when the processing module determines that the trigger condition is satisfied, send a first message to the access network device, the first message including identification information of the target host node. The first message is used by the access network device to determine whether to maintain the interface with the relay node.

[0106] Possible implementations of the communication method of the fifteenth aspect can refer to the various possible implementations of the fourth aspect.

[0107] For the technical effects brought about by various possible implementation methods of the fifteenth aspect, reference may be made to the introduction to the technical effects of the fourth aspect or various possible implementation methods of the fourth aspect.

[0108] In the sixteenth aspect, an embodiment of the present application provides another communication device, which has the function of implementing the behavior in the embodiment of the method of the fifth aspect above. The communication device can be a communication device, or a component of a communication device (such as a processor, a chip, or a chip system, etc.), or a logic module or software that can implement all or part of the functions of the communication device. The functions of the communication device can be implemented by hardware, or by hardware executing corresponding software implementations, and the hardware or software includes one or more modules or units corresponding to the above functions. In one possible implementation, the communication device includes a transceiver module and a processing module, wherein: the transceiver module is used to receive a first message, the first message includes configuration update information and / or identification information of a target host node of a relay node, and the configuration update information includes the IP address of the relay node under the target host node; the processing module is used to determine whether to maintain the interface with the relay node based on the first message.

[0109] In one possible implementation, the first message does not include the configuration update information; the transceiver module is further configured to receive the configuration update information from the relay node when the processing module determines to maintain the interface with the relay node based on the first message.

[0110] In a possible implementation, the processing module is further configured to update the IP address of the relay node maintained by the processing module to the IP address of the relay node under the target host node when determining to maintain the interface with the relay node.

[0111] In a possible implementation manner, the processing module is further configured to initiate a process of removing the interface with the relay node when it is determined to remove the interface with the relay node.

[0112] In one possible implementation, the transceiver module is further used to send third removal indication information to the relay node when the processing module determines to remove the interface between the relay node and the access network device, and the third removal indication information is used to instruct the relay node to remove the interface between the relay node and the access network device.

[0113] In one possible implementation, the first message includes the configuration update information; the processing module is specifically used to determine to maintain the interface between the access network device and the relay node when the benefit value of the interface between the access network device and the relay node is higher than or equal to a preset threshold; otherwise, determine to remove the interface between the relay node.

[0114] In one possible implementation, the first message includes identification information of the target host node of the relay node; the processing module is specifically used to determine to remove the interface between the access network device and the target host node when the access network device cannot communicate with the target host node through IP routing; otherwise, determine to maintain the interface between the access network device and the relay node.

[0115] For possible implementations of the communication method of the sixteenth aspect, reference can be made to various possible implementations of the fifth aspect.

[0116] For the technical effects brought about by various possible implementation methods of the sixteenth aspect, reference may be made to the introduction to the technical effects of the fifth aspect or various possible implementation methods of the fifth aspect.

[0117] In the seventeenth aspect, an embodiment of the present application provides another communication device, which has the function of implementing the behavior in the embodiment of the method of the sixth aspect above. The communication device can be a communication device, or a component of a communication device (such as a processor, a chip, or a chip system, etc.), or a logic module or software that can implement all or part of the functions of the communication device. The functions of the communication device can be implemented by hardware, or can be implemented by hardware executing corresponding software, and the hardware or software includes one or more modules or units corresponding to the above functions. In one possible implementation, the communication device includes a transceiver module and a processing module, wherein: the processing module is used to determine whether a trigger condition is met, and the trigger condition includes at least one of the following: the MT of the relay node is about to be switched, the MT has been switched to the target host node, the MT is performing RRC re-establishment, or the RRC re-establishment of the MT under the target host node is completed; the transceiver module is used to send a first removal indication message to the access network device, and the first removal indication message is used to instruct the access network device to remove the interface between the access network device and the relay node.

[0118] For possible implementations of the communication method of the seventeenth aspect, reference may be made to various possible implementations of the sixth aspect.

[0119] For the technical effects brought about by various possible implementation methods of the seventeenth aspect, reference may be made to the introduction to the technical effects of the sixth aspect or various possible implementation methods of the sixth aspect.

[0120] In an eighteenth aspect, an embodiment of the present application provides another communication device, which has the function of implementing the behavior in the embodiment of the method of the seventh aspect above. The communication device can be a communication device, or a component of a communication device (such as a processor, a chip, or a chip system, etc.), or a logic module or software that can implement all or part of the functions of the communication device. The functions of the communication device can be implemented by hardware, or can be implemented by hardware executing corresponding software, and the hardware or software includes one or more modules or units corresponding to the above functions. In one possible implementation, the communication device includes a transceiver module and a processing module, wherein: the processing module is used to determine whether a trigger condition is met, and the trigger condition includes at least one of the following: the MT of the relay node is about to be switched, the MT has been switched to the target host node, the MT is performing RRC re-establishment, or the RRC re-establishment of the MT under the target host node is completed; the transceiver module is used to send a third removal indication message to the relay node, and the third removal indication message is used to instruct the relay node to remove the interface between it and the access network device.

[0121] For possible implementations of the communication method of the eighteenth aspect, reference may be made to various possible implementations of the seventh aspect.

[0122] For the technical effects brought about by various possible implementation methods of the eighteenth aspect, reference may be made to the introduction to the technical effects of the seventh aspect or various possible implementation methods of the seventh aspect.

[0123] In a nineteenth aspect, an embodiment of the present application provides another communication device, which has the function of implementing the behavior in the embodiment of the method of the eighth aspect above. The communication device can be a communication device, or a component of a communication device (such as a processor, a chip, or a chip system, etc.), or a logic module or software that can implement all or part of the functions of the communication device. The functions of the communication device can be implemented by hardware, or by hardware executing corresponding software implementations, and the hardware or software includes one or more modules or units corresponding to the above functions. In one possible implementation, the communication device includes a transceiver module and a processing module, wherein: the processing module is used to determine whether the interface between the relay node and the access network device needs maintenance; the transceiver module is used to send maintenance indication information to the relay node when the processing module determines that the interface between the relay node and the access network device needs maintenance, and / or send configuration update information to the access network device, wherein the maintenance indication information is used to instruct the relay node to maintain the interface between the relay node and the access network device, and the configuration update information includes the IP address of the relay node under the target host node.

[0124] In one possible implementation, the processing module is also used to send a fourth removal indication message to the relay node and / or send a first removal indication message to the access network device when it is determined that the interface between the relay node and the access network device needs to be removed, wherein the fourth removal indication message is used to instruct the relay node to remove the interface between the relay node and the access network device, and the first removal indication message is used to instruct the access network device to remove the interface between the relay node and the access network device.

[0125] In a possible implementation, the transceiver module is further configured to receive a second message from the relay node or a source host node of the relay node, where the second message includes identification information of the access network device.

[0126] In one possible implementation, the processing module is specifically used to determine whether the interface between the relay node and the access network device needs maintenance based on whether the target host node and the access network device can communicate through IP routing; or, based on whether there is an interface between the target host node and the access network device, determine whether the interface between the relay node and the access network device needs maintenance; or, based on the benefit value of the interface between the target host node and the access network device, determine whether the interface between the relay node and the access network device needs maintenance.

[0127] Possible implementations of the communication method of the nineteenth aspect can refer to the various possible implementations of the eighth aspect.

[0128] Regarding the technical effects brought about by various possible implementation methods of the nineteenth aspect, reference may be made to the introduction to the technical effects of the eighth aspect or various possible implementation methods of the eighth aspect.

[0129] In the twentieth aspect, an embodiment of the present application provides another communication device, which has the function of implementing the behavior in the embodiment of the method of the ninth aspect above. The communication device can be a communication device, or a component of a communication device (such as a processor, a chip, or a chip system, etc.), or a logic module or software that can implement all or part of the functions of the communication device. The functions of the communication device can be implemented by hardware, or can be implemented by hardware executing corresponding software, and the hardware or software includes one or more modules or units corresponding to the above functions. In one possible implementation, the communication device includes a transceiver module and a processing module, wherein: the transceiver module is used to receive maintenance indication information from the target host node of the relay node, and the maintenance indication information is used to instruct the relay node to maintain the interface between the relay node and the access network device; the processing module is used to generate configuration update information; the transceiver module is also used to send the configuration update information to the access network device, and the configuration update information includes the IP address of the relay node under the target host node. The configuration update information is used to maintain the interface between the relay node and the access network device.

[0130] In a possible implementation, the transceiver module is further configured to send a second message to the source host node of the relay node or the target host node, where the second message includes identification information of the access network device.

[0131] For possible implementations of the communication method of the twentieth aspect, reference may be made to various possible implementations of the ninth aspect.

[0132] For the technical effects brought about by various possible implementation methods of the twentieth aspect, reference may be made to the introduction to the technical effects of the ninth aspect or various possible implementation methods of the ninth aspect.

[0133] In the twenty-first aspect, an embodiment of the present application provides another communication device, which has the function of implementing the behavior in the method embodiment of the tenth aspect above. The communication device can be a communication device, or a component of a communication device (such as a processor, a chip, or a chip system, etc.), or a logic module or software that can implement all or part of the functions of the communication device. The functions of the communication device can be implemented by hardware, or by hardware executing corresponding software implementations, and the hardware or software includes one or more modules or units corresponding to the above functions. In one possible implementation, the communication device includes a transceiver module and a processing module, wherein: the transceiver module is used to receive a fourth removal indication information from the target host node of the relay node, and the fourth removal indication information is used to instruct the relay node to remove the interface between the relay node and the access network device; the processing module is used to initiate a process of removing the interface between the relay node and the access network device in response to the fourth removal indication information.

[0134] In a possible implementation, the transceiver module is further configured to send a second message to the source host node of the relay node or the target host node, where the second message includes identification information of the access network device.

[0135] Possible implementations of the communication method of the twenty-first aspect can refer to the various possible implementations of the tenth aspect.

[0136] Regarding the technical effects brought about by various possible implementation methods of the twenty-first aspect, reference may be made to the introduction to the technical effects of the tenth aspect or various possible implementation methods of the tenth aspect.

[0137] In the twenty-second aspect, an embodiment of the present application provides another communication device, which has the function of implementing the behavior in the method embodiment of the eleventh aspect above. The communication device can be a communication device, or a component of a communication device (such as a processor, a chip, or a chip system, etc.), or a logic module or software that can implement all or part of the functions of the communication device. The functions of the communication device can be implemented by hardware, or by hardware executing corresponding software implementations, and the hardware or software includes one or more modules or units corresponding to the above functions. In one possible implementation, the communication device includes a transceiver module and a processing module, wherein: the transceiver module is used to receive a first removal indication message from a target host node of a relay node, and the first removal indication message is used to instruct the access network device to remove the interface between the access network device and the relay node; the processing module is used to initiate a process of removing the interface between the access network device and the relay node in response to the first removal indication message.

[0138] Possible implementations of the communication method in aspect 22 may refer to various possible implementations in aspect 11.

[0139] Regarding the technical effects brought about by various possible implementation methods of the twenty-second aspect, please refer to the introduction to the technical effects of the eleventh aspect or various possible implementation methods of the eleventh aspect.

[0140] In the twenty-third aspect, an embodiment of the present application provides another communication device, which includes a processor, which is coupled to a memory, and the memory is used to store programs or instructions. When the program or instructions are executed by the processor, the communication device executes the method shown in any one of the above-mentioned first aspect to the above-mentioned eleventh aspect.

[0141] In the embodiment of the present application, during the execution of the above method, the process of sending information (or signals) in the above method can be understood as the process of outputting information based on the instructions of the processor. When outputting information, the processor outputs the information to the transceiver so that it can be transmitted by the transceiver. After being output by the processor, the information may also need to undergo other processing before reaching the transceiver. Similarly, when the processor receives input information, the transceiver receives the information and inputs it into the processor. Furthermore, after the transceiver receives the information, the information may need to undergo other processing before being input into the processor.

[0142] For operations such as sending and / or receiving involved in the processor, unless otherwise specified, or unless they conflict with their actual functions or internal logic in the relevant descriptions, they can be generally understood as instructions output based on the processor.

[0143] During implementation, the processor may be a processor specifically configured to execute these methods, or may be a processor that executes computer instructions in a memory to execute these methods, such as a general-purpose processor. For example, the processor may also be configured to execute a program stored in a memory. When the program is executed, the communication device performs the method described in the first aspect or any possible implementation of the first aspect.

[0144] In a possible implementation, the memory is located outside the communication device. In a possible implementation, the memory is located inside the communication device.

[0145] In a possible implementation, the processor and the memory may also be integrated into one device, that is, the processor and the memory may also be integrated together.

[0146] In a possible implementation, the communication device further includes a transceiver, and the transceiver is used to receive signals or send signals.

[0147] In aspect 24, the present application provides another communication device, which includes a processing circuit and an interface circuit, wherein the interface circuit is used to acquire data or output data; the processing circuit is used to execute the method shown in any one of aspects 1 to 11 above.

[0148] In aspect 25, the present application provides a computer-readable storage medium, which stores a computer program, and the computer program includes program instructions, which, when executed, enable the computer to execute the method shown in any one of aspects 1 to 11 above.

[0149] In aspect 26, the present application provides a computer program product, which includes a computer program, and the computer program includes program instructions, which, when executed, enable the computer to execute the method shown in any one of aspects 1 to 11 above.

[0150] In aspect 27, the present application provides a chip comprising a processor and a communication interface, wherein the communication interface is used for sending and receiving signals of the chip; the processor is used to execute computer program instructions so that a communication device comprising the chip executes a method as shown in any one of aspects 1 to 11 above. BRIEF DESCRIPTION OF THE DRAWINGS

[0151] FIG1 is an example of a VMR scenario provided by an embodiment of the present application;

[0152] FIG2 is a schematic diagram of a WAB network provided in an embodiment of the present application;

[0153] FIG3 is an example of another VMR scenario provided in an embodiment of the present application;

[0154] FIG4 is a flow chart of a communication method provided in an embodiment of the present application;

[0155] FIG5 is a flow chart of another communication method provided in an embodiment of the present application;

[0156] FIG6 is a flow chart of another communication method provided in an embodiment of the present application;

[0157] FIG7 is a flow chart of another communication method provided in an embodiment of the present application;

[0158] FIG8 is a flow chart of another communication method provided in an embodiment of the present application;

[0159] FIG9 is a flow chart of another communication method provided in an embodiment of the present application;

[0160] FIG10 is a flow chart of another communication method provided in an embodiment of the present application;

[0161] FIG11 is a flow chart of another communication method provided in an embodiment of the present application;

[0162] FIG12 is a flow chart of another communication method provided in an embodiment of the present application;

[0163] FIG13 is a flow chart of another communication method provided in an embodiment of the present application;

[0164] FIG14 is a flow chart of another communication method provided in an embodiment of the present application;

[0165] FIG15 is a flow chart of another communication method provided in an embodiment of the present application;

[0166] FIG16 is a flow chart of another communication method provided in an embodiment of the present application;

[0167] FIG17 is a flow chart of another communication method provided in an embodiment of the present application;

[0168] FIG18 is a schematic diagram of an O-RAN architecture provided in an embodiment of the present application;

[0169] FIG19 is a flow chart of another communication method provided in an embodiment of the present application;

[0170] FIG20 is a schematic structural diagram of a communication device 2000 provided in an embodiment of the present application;

[0171] FIG21 is a schematic structural diagram of another device 210 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0172] The terms "first" and "second" in the specification, claims and drawings of the present application are only used to distinguish different objects, rather than to describe a specific order. It will be understood that the various digital numbers involved in the embodiments of the present application are only for the convenience of description and are not used to limit the scope of the embodiments of the present application. The size of the sequence number of each of the above processes does not mean the order of execution, and the order of execution of each process should be determined by its function and inherent logic. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0173] The "embodiment" mentioned in this document means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present 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 that is mutually exclusive with other embodiments. It can be understood explicitly and implicitly by those skilled in the art that the embodiments described herein can be combined with other embodiments. In this application, the naming of messages is only used to distinguish different messages and should not be understood as a limitation. In other words, the name of any message in this application can be replaced with other names, and this application is not limited.

[0174] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification of the present application and the appended claims, the singular expressions "one", "a kind of", "said", "above", "the" and "this" are intended to also include plural expressions, unless there is a clear contrary indication in the context. It should also be understood that the term "and / or" used in the present application refers to and includes any or all possible combinations of one or more listed items. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The term "multiple" used in the present application refers to two or more. In the textual description of the present application, the character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0175] It is understood that in each embodiment of the present application, "A corresponds to B" means that there is a corresponding relationship between A and B, and B can be determined according to A. However, it should also be understood that determining (or generating) B according to (or based on) A does not mean that B is determined (or generated) only according to (or based on) A, and B can also be determined (or generated) according to (or based on) A and / or other information.

[0176] It should be understood that, in this application, indication includes direct indication (also known as explicit indication) and implicit indication. Direct indication of information A refers to including information A; implicit indication of information A refers to indicating information A through the correspondence between information A and information B and the direct indication of information B. The correspondence between information A and information B can be predefined, pre-stored, pre-burned, or pre-configured.

[0177] It should be understood that, in this application, information C is used to determine information D, which includes both information D being determined solely based on information C and information D being determined based on information C and other information. Furthermore, information C can also be used to determine information D indirectly, for example, where information D is determined based on information E, and information E is determined based on information C.

[0178] In addition, in each embodiment of the present application, "network element A sends information A to network element B" can be understood as the destination end of the information A or the intermediate network element in the transmission path between the destination end and the network element B, which may include directly or indirectly sending information to network element B. "Network element B receives information A from network element A" can be understood as the source end of the information A or the intermediate network element in the transmission path between the source end and the network element A, which may include directly or indirectly receiving information from network element A. The information may be processed as necessary between the source end and the destination end of the information transmission, such as format changes, but the destination end can understand the valid information from the source end. Similar expressions in this application can be understood similarly and will not be elaborated here.

[0179] To facilitate understanding of the embodiments of the present application, the following is a brief description of the terms and technical features involved in the embodiments of the present application.

[0180] Wireless access and backhaul (WAB), the application scenario can be a VMR scenario. Figure 1 provides an example of a VMR scenario for an embodiment of the present application. As shown in Figure 1, relay nodes (such as relay node #1, relay node #2, and relay node #3) access the host base station (also called donor) (such as access network device #1, access network device #2, and access network device #3) through wireless backhaul; the relay node is deployed on a car (or even on an airplane) to provide wireless coverage for the UE in the car (or even in the airplane) to overcome the problem of poor wireless signal in the car. In the VMR scenario, the relay node will move.

[0181] The WAB architecture can be a layer 3 relay network architecture. In other words, the WAB network can be a layer 3 relay-based network. Some or all of the relay nodes in the WAB architecture are complete base stations with the CU function of a base station and the DU function of a base station. In this application, the relay node includes a base station function (i.e., the CU function of a base station and the DU function of a base station) and an MT function. In other words, the relay node includes a gNB function (i.e., a base station function) and an MT function. In other words, the relay node includes a base station part (for implementing the base station function) and an MT part (for implementing the MT function). The relay node can have a complete protocol stack. The relay node in this application can be a version 19 relay node (i.e., having a base station function and an MT function), or it can be other nodes having a base station function and an MT function. The version 19 relay node is currently named a WAB node. In this application, the naming of the relay node is not limited, and the WAB node is hereinafter referred to as a relay node having a base station function and an MT function. A WAB node consists of a WAB-MT and a WAB-gNB (i.e., a base station). The WAB-gNB provides access services to UEs, while the WAB-MT provides backhaul. In one possible implementation, the relay node can also include some UPF functionality, allowing the relay node to provide more service capabilities (such as edge computing and sensing).

[0182] An example of a WAB network is shown in Figure 2. Figure 2 is a schematic diagram of a WAB network provided by an embodiment of the present application. As shown in Figure 2, the WAB node includes a gNB function (i.e., a base station function) and an MT function; the UE accesses the gNB function of the WAB node (i.e., WAB-gNB) through the Uu port, and then the MT function of the WAB node (i.e., WAB-MT) wraps the UE's data in its own PDU session, and sends it through the Uu port of the WAB-MT, through the host base station (donor) of the WAB-MT to the UPF (i.e., MT_UPF) network element of the WAB-MT; then, the UPF network element of the WAB-MT removes the WAB-MT-related packet header information, exposing the UE-related packet header information, and sends it to the UPF (i.e., UE_UPF) network element of the UE according to IP routing. Logically, a PDU session is also established between the UE and the UE's UPF network element, but this is transmitted wrapped in the PDU session of the WAB-MT. The above example illustrates how user-plane data transmission is performed between the UE and its UPF network element. The control-plane transmission between the WAB-gNB and the access and mobility management function (AMF) network element is similar and is also wrapped in the WAB-MT PDU session. The WAB-MT UPF network element forwards the data to the WAB-gNB AMF network element via IP routing, namely the UE / WAB_AMF network element. The host base station (also known as the host node) is a base station that supports WAB node access, such as a gNB, and is used to transmit WAB-MT service data. The AMF network element is a mobility management function network element of the core network. In this application, the main information involved is the establishment of a PDU session between the AMF network element and the UE or base station through the non-access stratum (NAS) or NG interaction. The UE / WAB_AMF network element is an AMF network element that serves the UE and WAB-gNB under the WAB network. The MT_AMF network element refers to the AMF network element that serves the WAB-MT. The N2 interface is the interface between the gNB (including WAB-gNB and host base station) and the AMF network element. The N3 interface is the interface between the gNB (including WAB-gNB and host base station) and the UPF network element. The N6 interface is the interface between network elements in the data network, specifically, the interface between UPF network elements or the interface between the UPF network element and the AMF. It is currently unclear whether a logical Xn interface needs to be established between the WAB-gNB and the host base station, and between the WAB-gNB and other nearby base stations (i.e., neighboring stations).

[0183] In a WAB network, the access link and backhaul link can be decoupled, meaning they can be operated by different operators. The access link is the Uu interface link between the UE and the WAB-gNB, while the backhaul link is the Uu interface link between the WAB-MT and the host node. For example, if a WAB node is deployed on an airplane (or aircraft), the access link is operated by the airline, while the backhaul link may be operated by a ground operator. The WAB-MT is a subscriber of the ground operator, and as long as the ground operator charges the WAB-MT, the UE on the flight does not necessarily have to be a subscriber of the ground operator. This facilitates flexible deployment and stimulates more diverse business models.

[0184] IP routing: IP routing refers to the process whereby after Xn data between a WAB-gNB and a base station with an Xn interface reaches the donor base station, the donor base station decodes the Xn data at the IP layer and forwards it based on the destination IP address of the Xn data. Xn data includes XnAP data on the control plane, used for exchanging control information between gNBs, and Xn interface data (Xn-U) on the user plane, used for data forwarding between gNBs.

[0185] XnAP routing: XnAP routing refers to XnAP data transmission between the WAB-gNB and the base station with an Xn interface. It is divided into XnAP data transmission between the WAB-gNB and the host base station and XnAP data transmission between the host base station and the base station with an Xn interface. The host base station decodes XnAP data to the XnAP layer and forwards it based on the identifier carried in the XnAP data.

[0186] As described above in the background art, the prior art does not provide a solution for maintaining the interface between the relay node and the access network device (e.g., other base stations and / or host base stations in FIG2 ) after the MT (e.g., WAB-MT) of the relay node undergoes a cross-host node handover or a cross-host node RRC re-establishment. An embodiment of the present application provides a solution for maintaining the interface between the relay node and the access network device after the MT (e.g., WAB-MT) of the relay node undergoes a cross-host node handover or a cross-host node RRC re-establishment, that is, a solution for maintaining the interface between the relay node and the access network device (e.g., other base stations and / or host base stations in FIG2 ).

[0187] The technical solution provided in the embodiment of the present application can be applied to scenarios where the MT of the relay node switches across host nodes or re-establishes RRC across host nodes, such as VMR scenarios (see Figure 1). Figure 3 is an example of another VMR scenario provided in the embodiment of the present application. In the VMR scenario shown in Figure 3, the WAB node is mobile, and the MT of WAB node #1 switches across host nodes or re-establishes RRC across host nodes during the movement. The MT of WAB node #1 switches from access network device #1 (i.e., the source host node of WAB node #1) to access network device #2 (i.e., the target host node of WAB node #1). The switching of the MT of WAB node #1 from its source host node to the target host node indicates that the MT of WAB node #1 switches across host nodes or re-establishes RRC across host nodes during the movement. The number of access network devices and the number of WAB nodes in the VMR scenario are not limited. In this embodiment of the present application, an Xn interface can be established between the WAB-gNB and an access network device (e.g., a gNB). The host node of the relay node can directly forward Xn interface data (i.e., the aforementioned Xn data) via IP routing or XnAP routing. The following describes the communication solution provided by this embodiment of the present application in conjunction with the accompanying drawings.

[0188] FIG4 is a flow chart of a communication method provided by an embodiment of the present application. FIG4 describes how to determine whether to maintain the interface between the relay node and the access network device and how to maintain the interface. As shown in FIG4, the method includes:

[0189] 401. When a trigger condition is met, the relay node determines whether to maintain the first interface.

[0190] In the present application, the relay node is described by taking the WAB node as an example, and the WAB node includes WAB-gNB and WAB-MT (abbreviated as MT). Maintaining an interface (such as the first interface) means maintaining the interface in a state where it can continue to be used, that is, the interface can be used until it is removed. In the present application, maintenance (maintain) can be replaced by maintenance, retention, or continued use, etc. Not maintaining an interface can be removing (remove), deleting (delete), or canceling (cancel) the interface, etc., and the following description will be taken as an example of removing the interface. When the trigger condition is met, the relay node determines whether to maintain the first interface, which can be replaced by: the relay node determines whether to maintain the first interface after the trigger condition is met. The above-mentioned first interface is the interface between the above-mentioned relay node and the access network device (excluding its source host node). In a possible implementation, the above-mentioned relay node includes a base station function and an MT function, and the above-mentioned first interface is an Xn interface. It should be understood that the first interface is an example of an interface between a relay node and an access network device. The embodiment of the present application takes how to determine whether to maintain the first interface and how to maintain the first interface as an example to describe how to determine whether to maintain the interface between the relay node and each access network device and how to maintain these interfaces. For example, step 401 can be replaced by: when the trigger condition is met, the relay node determines whether to maintain the interface between the relay node and each access network device. For another example, step 401 can be replaced by: when the trigger condition is met, the relay node determines the interface that needs to be maintained and / or the interface that needs to be removed among the interfaces between the relay node and each access network device.

[0191] The triggering conditions include at least one of the following: the MT of the relay node is about to be handed over, the MT has been handed over to the target host node of the relay node, or the RRC re-establishment of the MT under the target host node is completed. The source host node (source (old) donor) refers to the host node to which the MT is connected before the MT of the relay node is handed over across host nodes or RRC re-established across host nodes, that is, the host node with which the MT has an RRC connection. The target host node (target (new) donor) refers to the host node to which the MT is connected after the MT of the relay node is handed over across host nodes or RRC re-established across host nodes, that is, the host node with which the MT has an RRC connection. When the MT of the relay node is about to be handed over, there is an RRC connection between the MT and its source host node. The fact that the MT has handed over to the target host node of the relay node indicates that the RRC connection between the MT and its source host node has been disconnected, and an RRC connection between the MT and its target host node has been established. The fact that the MT has been handed over to the target host node of the relay node indicates that the RRC re-establishment of the MT under the target host node indicates that the MT has established an RRC connection between the MT and its target host node.

[0192] The relay node may determine whether to maintain the first interface when determining that the trigger condition is met. The relay node may determine that the trigger condition is met in the following ways: the relay node receives a handover command, or the relay node successfully randomly accesses the target host node, or the relay node successfully re-establishes an RRC connection with the target host node (e.g., the relay node sends an RRC Reestablishment Complete message to the target host).

[0193] The embodiments of the present application do not limit the specific implementation of the relay node determining whether to maintain the first interface. A possible implementation of the relay node determining whether to maintain the first interface is as follows: when the relay node and the access network device cannot communicate through IP routing, determine to remove the first interface, otherwise, determine to maintain the first interface; or, when the benefit value (benefit value) of the interface between the relay node and the access network device is higher than or equal to a preset threshold, determine to maintain the first interface, otherwise, determine to remove the first interface. The preset threshold can be set according to actual needs and is not limited by this application. When the relay node and the access network device cannot communicate through IP routing, determine to remove the first interface; the resource overhead of maintaining the first interface can be saved. When the benefit value of the interface between the relay node and the access network device is higher than or equal to a preset threshold, determine to maintain the first interface; so that subsequent data transmission through the first interface brings better communication gain.

[0194] 402A. When the relay node determines to maintain the first interface, it sends configuration update information to the access network device.

[0195] The configuration update information includes the IP address of the relay node under the target host node and, optionally, identification information of the relay node and / or the IP address of the relay node under the source host node. For example, the identification information of the relay node is the gNB identity (ID) of the relay node, i.e., the WAB gNB ID. The configuration update information is used to maintain the first interface. In other words, the configuration update information is used by the access network device or the source host node to maintain the first interface. Optionally, the configuration update information also includes identification information (gNB ID and / or IP address) of the target host node. If Xn data between the access network device and the relay node is routed via IP on the target host node, as long as the access network device knows the IP address of the relay node, the Xn data can correctly reach the target host node according to IP routing rules, without the need to indicate the identification information of the target host node to the access network device. Therefore, the identification information of the target host node in the configuration update information is optional. If Xn data between an access network device and a relay node is routed via an XnAP on the target host node, the relay node needs to indicate the target host node's identification information to the access network device. This means that the configuration update information must include the target host node's identification information. In one possible implementation, the configuration update information is carried in an Xn message, i.e., a message sent over the Xn interface. Exemplarily, the configuration update information is carried in an NG-RAN NODE CONFIGURATION UPDATE message.

[0196] 403A. The access network device maintains the interface with the relay node based on the configuration update information.

[0197] In one possible implementation, the access network device updates the IP address of the relay node maintained by the access network device to the IP address of the relay node under the target host node based on the configuration update information. Steps 402A and 403A are optional.

[0198] 402B. When the relay node determines to remove the first interface, it initiates a process of removing the first interface.

[0199] Exemplarily, the process of removing the first interface is an Xn interface removal process. The relay node may initiate the process of removing the first interface by sending an XN removal request (REMOVAL REQUEST) message. The XN removal request message is used to request removal of the first interface.

[0200] 403B: The relay node and the access network device execute a process of removing the first interface.

[0201] Step 402B and step 403B are optional. A possible implementation of step 403B is as follows: releasing the relevant configuration of the first interface, such as the IP address, port number, etc.

[0202] 402C. When the relay node determines to remove the first interface, the relay node sends first removal instruction information to the access network device.

[0203] Accordingly, the access network device receives first removal instruction information from the relay node. The first removal instruction information is used to instruct the access network device to remove the interface between the access network device and the relay node. The first removal instruction information may include identification information of the relay node or the IP address of the relay node under the source host node.

[0204] 403C. In response to the first removal instruction information, the access network device initiates a process of removing the first interface.

[0205] The access network device may initiate a process of removing the first interface by sending an XN removal request message.

[0206] 404C: The relay node and the access network device execute a process of removing the first interface.

[0207] Steps 402C and 404C are optional. Steps 402A to 403A, steps 402B to 403B, and steps 402C to 404C are three parallel solutions. The method flow in FIG4 includes steps 402A to 403A, steps 402B to 403B, or steps 402C to 404C.

[0208] In an embodiment of the present application, the relay node determines whether to maintain the first interface, and when it determines to maintain the first interface, sends configuration update information to the access network device so that the access network device maintains the first interface; an interface maintenance solution between the relay node and the access network device is provided. In addition, by maintaining the first interface, the subsequent target host node can forward data to the access network device (such as a base station) that has an Xn interface with the relay node through the IP network on the RAN side, and does not need to be sent to the core network and then sent to other access network devices through the core network; transmission efficiency can be improved. The embodiment of the present application takes into account the Xn interface maintenance problem during the movement of the WAB node and supports the mobility of the WAB node.

[0209] FIG5 is a flow chart of another communication method provided by an embodiment of the present application. FIG5 describes how to determine whether to maintain the interface between the relay node and its source host node and how to maintain the interface. The first interface in the method flow of FIG4 is the interface between the relay node and the access network device, and the first interface in the method flow of FIG5 is the interface between the relay node and its source host interface. As shown in FIG5, the method includes:

[0210] 501. When a trigger condition is met, the relay node determines whether to maintain a first interface.

[0211] Step 501 may refer to step 401 in Figure 4. The first interface is an interface between the relay node and its source host node.

[0212] The embodiments of the present application do not limit the specific implementation of the relay node determining whether to maintain the first interface. Another possible implementation of the relay node determining whether to maintain the first interface is as follows: when the relay node and the source host node will not be able to communicate through IP routing, determine to remove the first interface, otherwise, determine to maintain the first interface; and / or, when the benefit value of the interface between the relay node and the source host node is higher than or equal to a preset threshold, determine to maintain the first interface, otherwise, determine to remove the first interface. When the relay node and the source host node will not be able to communicate through IP routing, determine to remove the first interface; the resource overhead of maintaining the first interface can be saved. When the benefit value of the interface between the relay node and the source host node is higher than or equal to a preset threshold, determine to maintain the first interface; so that subsequent data transmission through the first interface brings better communication gain.

[0213] 502A. When the relay node determines to maintain the first interface, it sends configuration update information to its source host node.

[0214] Step 502A can refer to step 402A in Figure 4. The configuration update information is used to maintain the first interface described above. Optionally, the configuration update information also includes identification information of the target host node (gNB ID and / or IP address). If the Xn data between the source host node and the relay node is routed via IP on the target host node, as long as the source host node knows the IP address of the relay node, the Xn data can correctly reach the target host node according to the IP routing rules, and there is no need to indicate the identification information of the target host node to the source host node. Therefore, the identification information of the target host node in the configuration update information is optional. If the Xn data between the source host node and the relay node is routed via XnAP on the target host node, the relay node needs to indicate the identification information of the target host node to the source host node, that is, the identification information of the target host node needs to be included in the configuration update information.

[0215] 503A: The source host node maintains the interface with the relay node based on the configuration update information.

[0216] In one possible implementation, the source host node updates the IP address of the relay node maintained by itself to the IP address of the relay node under the target host node based on the configuration update information. Steps 502A and 503A are optional.

[0217] 502B. When the relay node determines to remove the first interface, it initiates a process of removing the first interface.

[0218] Step 502B may refer to step 402B in FIG. 4 .

[0219] 503B: The relay node and the source host node execute a process of removing the first interface.

[0220] Step 502B and step 503B are optional. For step 503B, please refer to step 403B in FIG4 .

[0221] 502C. When the relay node determines to remove the first interface, the relay node sends second removal indication information to the source host node.

[0222] Correspondingly, the source host node receives second removal instruction information from the relay node. The second removal instruction information is used to instruct the source host node to remove the interface between the source host node and the relay node. The second removal instruction information includes identification information of the relay node or the IP address of the relay node under the source host node.

[0223] 503C. In response to the second removal instruction information, the source host node initiates a process of removing the first interface.

[0224] 504C: The relay node and the source host node execute a process of removing the first interface.

[0225] Step 504C may refer to step 403B. Steps 502C and 504C are optional. Steps 502A to 503A, steps 502B to 503B, and steps 502C to 504C are three parallel solutions. The method flow in Figure 5 includes steps 502A to 503A, steps 502B to 503B, or steps 502C to 504C.

[0226] In an embodiment of the present application, a relay node determines whether to maintain a first interface, and when determining to maintain the first interface, sends configuration update information to a source host node so that the source host node can maintain the first interface. This provides an interface maintenance solution between the relay node and the source host node. Furthermore, by maintaining the first interface, the target host node can subsequently forward data to the source host node connected to the relay node via the IP network on the RAN side, eliminating the need to forward data to the core network and then to other access network devices via the core network. This can improve transmission efficiency.

[0227] In the method flow of Figure 4, the relay node determines (or decides) whether to maintain the interface with the access network device. In the method flow of Figure 5, the relay node determines whether to maintain the interface with its source host node. The following describes how the relay node directly removes the old interface (including the interface between the relay node and the access network device, and / or the interface between the relay node and its source host node) when the trigger condition is met. Figure 6 is a flow chart of another communication method provided by an embodiment of the present application. In the method flow of Figure 6, the relay node directly removes the old interface when the trigger condition is met, without determining whether the old interface needs to be maintained. As shown in Figure 6, the method includes:

[0228] 601. The relay node determines that a trigger condition is met.

[0229] The triggering condition includes at least one of the following: the mobile terminal of the relay node is about to be handed over, the mobile terminal has been handed over to the target host node of the relay node, or the mobile terminal has completed RRC re-establishment under the target host node. For step 601, please refer to the description of possible ways for the relay node to determine whether the triggering condition is met in Figure 4, and the steps are not repeated here.

[0230] 602A: The relay node initiates a process of removing the first interface.

[0231] In one possible implementation, upon determining that a trigger condition is met, the relay node initiates a process for removing the first interface. Step 602A can refer to step 402B in Figure 4 . The first interface is the interface between the relay node and the access network device. Alternatively, the first interface is the interface between the relay node and its source host node.

[0232] 603A: The relay node and the access network device execute a process of removing the first interface.

[0233] Step 602A and step 603A are optional. For step 603A, please refer to step 403B in FIG4 .

[0234] 602B. The relay node sends first removal instruction information to the access network device.

[0235] Correspondingly, the access network device receives first removal instruction information from the relay node. The first removal instruction information is used to instruct the access network device to remove the interface between the access network device and the relay node.

[0236] 603B. In response to the first removal instruction information, the access network device initiates a process of removing the first interface.

[0237] 604B: The relay node and the access network device execute a process of removing the first interface.

[0238] Steps 602B to 604B are optional.

[0239] 602C. The relay node sends second removal indication information to the source host node.

[0240] Correspondingly, the source host node receives second removal instruction information from the relay node. The second removal instruction information is used to instruct the source host node to remove the interface between the source host node and the relay node.

[0241] 603C: In response to the second removal instruction information, the source host node initiates a process of removing the first interface.

[0242] Step 603C may refer to step 403C in FIG. 4 .

[0243] 604C: The relay node and the source host node execute a process of removing the first interface.

[0244] Steps 602C to 604C are optional. Steps 602A to 603A, step 602B to 604B, and step 602C to 604C are in parallel. The method flow in Figure 6 may include steps 602A to 603A, step 602B to 604B, or step 602C to 604C. In some possible embodiments, when the relay node determines that the trigger condition is met, it sends a removal indication message to each access network device that has an interface with the relay node, so that each access network device respectively initiates a process of removing the interface with the relay node; wherein each access network device may include a source host node or may not include a source host node. In some possible embodiments, when the relay node determines that the trigger condition is met, it initiates a process of removing the interface with each access network device; wherein each access network device may include a source host node or may not include a source host node.

[0245] In an embodiment of the present application, when the relay node determines that the trigger condition is met, it initiates the process of removing the first interface or sends a first removal indication message to the access network device or sends a second removal indication message to the source host node of the above-mentioned relay node; the resource overhead brought by maintaining the first interface can be avoided.

[0246] FIG7 is a flow chart of another communication method provided by an embodiment of the present application. In the method flow of FIG7 , when the source host node of the relay node determines that the trigger condition is met, it directly removes the old interface (i.e., the interface between the source host node and the relay node) without determining whether the old interface needs to be maintained. As shown in FIG7 , the method includes:

[0247] 701. The source host node determines that a trigger condition is met.

[0248] The triggering condition includes at least one of the following: the mobile terminal of the relay node is about to be handed over, the mobile terminal has been handed over to the target host node, the mobile terminal is performing RRC re-establishment, or the mobile terminal has completed RRC re-establishment at the target host node. The completion of RRC re-establishment of the mobile terminal at the target host node can be described as the completion of RRC re-establishment between the mobile terminal and the target host node.

[0249] One possible implementation of the source host node determining that the MT of the relay node will be switched is: based on the measurement report from the MT, determining that the MT will be switched to the target host node. For example, the source host node configures the trigger condition for reporting the measurement report for the MT, such as the signal quality of the source cell is lower than the threshold. The measurement report can carry information such as the signal quality of the source cell and the neighboring cell of the MT, as well as the physical cell identifier (PCI) of the neighboring cell. The source host node can also determine that the MT of the relay node will be switched by other means, which is not limited in this application. Another possible implementation of the source host node determining that the MT of the relay node will be switched is: the source host node sends a handover request (HANDOVER REQUEST) message about the MT to the target host node.

[0250] One possible implementation for the source host node to determine that the MT has been handed over to the target host node is: the source host node receives a HANDOVER SUCCESS message or a UE CONTEXT RELEASE message regarding the MT sent by the target host node. The HANDOVER SUCCESS message is used to indicate that the MT has been handed over to the target host node. The UE CONTEXT RELEASE message is used to instruct the source host node to release the MT's context. The source host node may also determine that the MT has been handed over to the target host node by other means, which are not limited in this application.

[0251] The source host node determines that the MT is performing RRC re-establishment (i.e., the MT is performing RRC re-establishment under the target host node). One possible implementation is to receive a UE CONTEXT RETRIEVE REQUEST message sent by the target host node, requesting the UE context from the source host node. Another possible implementation is to send a UE CONTEXT RETRIEVE Response message to the target host node. The UE CONTEXT RETRIEVE Response message carries the MT context.

[0252] One possible implementation of the source host node determining that the RRC re-establishment of the MT under the target host node is completed is: receiving a UE context release message from the target host node. The UE context release message is used to instruct the source host node to release the context of the MT.

[0253] 702A. The source host node sends first removal indication information to the access network device.

[0254] Accordingly, the access network device receives first removal instruction information from the source host node. Exemplarily, upon determining that the trigger condition is met, the first removal instruction information is sent to the access network device. The first removal instruction information is used to instruct the access network device to remove the interface between the access network device and the relay node. The first removal instruction information may include identification information of the relay node or the IP address of the relay node under the source host node.

[0255] 703A: In response to the first removal instruction information, the access network device initiates a process of removing the interface between the access network device and the relay node.

[0256] 704A: The access network device and the relay node execute a process of removing the interface between them.

[0257] Step 704A may refer to step 403B in Figure 4. Steps 702A to 704A are optional.

[0258] 702B. The source host node sends third removal indication information to the relay node.

[0259] Accordingly, the relay node receives third removal instruction information from the source host node. The third removal instruction information is used to instruct the relay node to remove the interface between the relay node and the access network device. Exemplarily, upon determining that the trigger condition is met, the third removal instruction information is sent to the relay node. The third removal instruction information may include identification information of the access network device or the IP address of the access network device.

[0260] 703B: In response to the third removal indication information, the relay node initiates a process of removing the interface between the relay node and the access network device.

[0261] 704B: The access network device and the relay node execute a process of removing the interface between them.

[0262] Steps 702B to 704B are optional. Steps 702A to 704A and step 702B to 704B are parallel solutions. The method flow of FIG7 includes steps 702A to 704A or steps 702B to 704B.

[0263] In this embodiment of the present application, upon determining that the trigger condition is met, the source host node sends a third removal instruction message to the relay node or sends a first removal instruction message to the access network device. In other words, upon determining that the trigger condition is met, the source host node directly instructs the relay node to remove the interface between the relay node and the access network device, thereby avoiding the resource overhead associated with maintaining the Xn interface.

[0264] FIG8 is a flow chart of another communication method provided by an embodiment of the present application. In the method flow of FIG8 , when the target host node of the relay node determines that the trigger condition is met, it directly removes the old interface (i.e., the interface between the source host node and the relay node) without determining whether the old interface needs to be maintained. As shown in FIG8 , the method includes:

[0265] 801. The target host node determines that a trigger condition is met.

[0266] The triggering condition includes at least one of the following: the mobile terminal of the relay node is about to be handed over, the mobile terminal has been handed over to the target host node, the mobile terminal is performing RRC re-establishment, or the mobile terminal has completed RRC re-establishment at the target host node. The completion of RRC re-establishment of the mobile terminal at the target host node can be described as the completion of RRC re-establishment between the mobile terminal and the target host node.

[0267] One possible implementation of the target host node determining that the MT of the relay node will be handed over is that the target host node receives a handover request (HANDOVER REQUEST) message from the source host node. The handover request message is used to request handover of the MT to the target host node.

[0268] One possible implementation for the target host node to determine that the MT has been handed over to the target host node is: the target host node sends a HANDOVER SUCCESS message or a UE CONTEXT RELEASE message regarding the MT to the source host node. The HANDOVER SUCCESS message is used to indicate that the MT has been handed over to the target host node. The UE CONTEXT RELEASE message is used to instruct the source host node to release the MT's context. The target host node may also determine that the MT has been handed over to the target host node by other means, which are not limited in this application.

[0269] The target host node determines that the MT is performing RRC re-establishment (i.e., the MT performs RRC re-establishment under the target host node). One possible implementation is: the target host node sends a UE Context Retrieval Request message to the source host node, requesting the MT's context. Another possible implementation is: the target host node receives a UE Context Retrieval Response message from the source host node. The UE Context Retrieval Response message carries the MT's context.

[0270] The target host node determines that the RRC re-establishment of the MT under the target host node is completed. One possible implementation is: the target host node sends a UE context release message to the source host node. The UE context release message is used to instruct the source host node to release the context of the MT.

[0271] 802A. The target host node sends first removal indication information to the access network device.

[0272] Accordingly, the access network device receives first removal instruction information from the target host node. Exemplarily, upon determining that the trigger condition is met, the target host node sends the first removal instruction information to the access network device. The first removal instruction information is used to instruct the access network device to remove the interface between the access network device and the relay node. The first removal instruction information may include identification information of the relay node or the IP address of the relay node under the source host node.

[0273] 803A: In response to the first removal instruction information, the access network device initiates a process of removing the interface between the access network device and the relay node.

[0274] 804A: The access network device and the relay node execute a process of removing the interface between them.

[0275] Step 804A may refer to step 403B in Figure 4. Steps 802A to 804A are optional.

[0276] 802B. The target host node sends third removal indication information to the relay node.

[0277] Accordingly, the relay node receives third removal instruction information from the target host node. The third removal instruction information is used to instruct the relay node to remove the interface between the relay node and the access network device. Exemplarily, upon determining that the trigger condition is met, the target host node sends the third removal instruction information to the relay node. The third removal instruction information may include identification information of the access network device or the IP address of the access network device.

[0278] 803B: In response to the third removal indication information, the relay node initiates a process of removing the interface between the relay node and the access network device.

[0279] 804B: The access network device and the relay node execute a process of removing the interface between them.

[0280] Steps 802B to 804B are optional. Steps 802A to 804A and step 802B to 804B are parallel solutions. The method flow of FIG8 includes steps 802A to 804A or steps 802B to 804B.

[0281] In this embodiment of the present application, upon determining that the trigger condition is met, the target host node sends a third removal instruction message to the relay node or sends the first removal instruction message to the access network device. In other words, upon determining that the trigger condition is met, the relay node is directly instructed to remove the interface between the relay node and the access network device, thereby avoiding the resource overhead associated with maintaining the Xn interface.

[0282] FIG9 is a flow chart of another communication method provided by an embodiment of the present application. In the method flow of FIG9 , an access network device having an interface with a relay node determines whether to maintain the interface with the relay node. As shown in FIG9 , the method includes:

[0283] 901A. The relay node determines that trigger condition #1 is satisfied.

[0284] Trigger condition #1 includes at least one of the following: the MT of the relay node is about to be handed over, the MT has been handed over to the target host node of the relay node, or the RRC re-establishment of the MT under the target host node is completed. Step 901A can refer to step 401 in Figure 4.

[0285] 902A. The relay node sends a first message to the access network device.

[0286] Accordingly, the access network device receives a first message from the relay node. The first message includes configuration update information and / or identification information of the target host node. The configuration update information includes the IP address of the relay node under the target host node, and optionally, also includes the identification information of the relay node and / or the IP address of the relay node under the source host node. Exemplarily, when it is determined that the trigger condition is met, the relay node sends a first message to the access network device. The above-mentioned configuration update information and / or the identification information of the above-mentioned target host node are used to determine whether the interface between the relay node and the access network device needs to be maintained. In other words, the configuration update information and / or the identification information of the target host node are used by the access network device to determine whether to maintain the interface with the relay node. Exemplarily, the first message can be an XnAP message. Step 901A and step 902A are optional.

[0287] 901B. The source host node determines that trigger condition #2 is met.

[0288] Trigger condition #2 includes at least one of the following: the MT of the relay node is about to be handed over, the MT has been handed over to the target host node, the MT is in the process of RRC re-establishment, or the MT has completed RRC re-establishment at the target host node. The completion of RRC re-establishment at the target host node can be described as the completion of RRC re-establishment between the MT and the target host node. Step 901B can refer to step 701 in Figure 7 .

[0289] 902B. The source host node sends a first message to the access network device.

[0290] Accordingly, the access network device receives the first message from the source host node. The first message in step 902B may be the same as the first message in step 902A. Steps 901B and 902B are optional.

[0291] 901C. The target host node determines that trigger condition #2 is satisfied.

[0292] Trigger condition #2 includes at least one of the following: the MT of the relay node is about to be handed over, the MT has been handed over to the target host node, the MT is in the process of RRC re-establishment, or the MT has completed RRC re-establishment at the target host node. The completion of RRC re-establishment at the target host node can be described as the completion of RRC re-establishment between the MT and the target host node. Step 901C can refer to step 801 in Figure 8 .

[0293] 902C. The target host node sends a first message to the access network device.

[0294] Accordingly, the access network device receives a first message from the target host node. The first message in step 902C may be the same as the first message in step 902A. Step 901C and step 902C are optional. Before executing step 902C, the target host node may obtain identification information of the access network device. Exemplarily, the target host node receives a handover request message from the source host node, the handover request message being used to request handover of the MT to the target host node, the handover request message including identification information of the access network device. Exemplarily, the target host node receives a UE CONTEXT RETRIEVE RESPONSE message from the source host node, the UE CONTEXT RETRIEVE RESPONSE message including identification information of the access network device. Exemplarily, the target host node receives an RRC message from the MT, the RRC message including identification information of the access network device.

[0295] Steps 901A to 902A, steps 901B to 902B, and steps 901C to 902C are three parallel solutions. The method flow in FIG9 includes steps 901A to 902A, steps 901B to 902B, or steps 901C to 902C.

[0296] 903. The access network device determines whether to maintain the interface with the relay node based on the first message.

[0297] In one possible implementation, the first message includes the configuration update information; the access network device determines to maintain the interface with the relay node when the benefit value of the interface between the access network device and the relay node is greater than or equal to a preset threshold; otherwise, the access network device determines to remove the interface with the relay node. In this implementation, the interface with the relay node is determined to be maintained when the benefit value of the interface between the access network device and the relay node is greater than or equal to the preset threshold, thereby achieving better communication gain for subsequent data transmission via the interface with the relay node.

[0298] In one possible implementation, the first message includes identification information of the target host node of the relay node; when the access network device cannot communicate with the target host node via IP routing, the access network device determines to remove the interface with the relay node; otherwise, the access network device determines to maintain the interface with the relay node. In this implementation, when the access network device cannot communicate with the target host node via IP routing, the access network device determines to remove the interface with the relay node; this can save resource overhead for maintaining the interface. When the access network device can communicate with the target host node via IP routing, the access network device determines to maintain the interface with the relay node so that data can be subsequently transmitted via the interface with the relay node.

[0299] Step 903 is optional, and the access network device may not need to determine whether to maintain the interface with the relay node. It defaults to the need for maintenance of the interface. After receiving the first message, it directly enters step 904B to update the configuration information, that is, to update the IP address of the relay node maintained by itself to the IP address of the relay node under the target host node.

[0300] 904A. When the access network device determines to remove the interface with the relay node, it initiates a process of removing the interface with the relay node.

[0301] The operation of the access network device initiating the process of removing the interface between the access network device and the relay node can be seen in step 403C of Figure 4. After the access network device initiates the process of removing the first interface, the relay node and the access network device execute the process of removing the first interface, see step 403B of Figure 4. Step 904A is optional.

[0302] 904B. When determining to maintain the interface between the access network device and the relay node, the access network device updates the IP address of the relay node maintained by the device to the IP address of the relay node under the target host node.

[0303] Step 904B is optional. The method flow of FIG9 includes step 904A or step 904B.

[0304] In an embodiment of the present application, the access network device determines, based on the first message, whether to maintain the interface with the relay node so as to subsequently remove or maintain the interface with the relay node. Alternatively, the access network device directly updates the relay node information based on the first message so as to subsequently maintain the interface with the relay node.

[0305] FIG10 is a flow chart of another communication method provided by an embodiment of the present application. In the method flow of FIG10 , an access network device having an interface with a relay node determines whether to maintain the interface with the relay node. The difference between the method flow of FIG10 and the method flow of FIG9 is that in the method flow of FIG9 , the access network device initiates the process of removing the interface with the relay node, while in the method flow of FIG10 , the relay node initiates the process of removing the interface with the access network device. As shown in FIG10 , the method includes:

[0306] 1001. The relay node determines that trigger condition #1 is met.

[0307] Step 1001 may refer to step 901A in FIG. 9 .

[0308] 1002. The relay node sends a first message to the access network device.

[0309] The first message includes the identification information of the target host node of the relay node, but does not include the above-mentioned configuration update information.

[0310] 1003. The access network device determines whether to maintain the interface with the relay node based on the first message.

[0311] In one possible implementation, the first message includes identification information of the target host node of the relay node; when the access network device cannot communicate with the target host node via IP routing, the access network device determines to remove the interface with the relay node; otherwise, the access network device determines to maintain the interface with the relay node. In this implementation, when the access network device cannot communicate with the target host node via IP routing, the access network device determines to remove the interface with the relay node; this can save resource overhead for maintaining the interface. When the access network device can communicate with the target host node via IP routing, the access network device determines to maintain the interface with the relay node so that data can be subsequently transmitted via the interface with the relay node.

[0312] 1004A: When the relay node does not receive the third removal indication information within a first preset time period after sending the first message, the relay node sends configuration update information to the access network device.

[0313] Accordingly, when the access network device determines to maintain the interface between the access network device and the relay node based on the first message, it receives configuration update information from the relay node. In one possible implementation, when the access network device determines to maintain the interface between the access network device and the relay node based on the first message, it does not send the third removal indication information to the relay node, and the third removal indication information is used to instruct the relay node to remove the interface between the access network device. Accordingly, when the relay node does not receive the third removal indication information within the first preset time period after sending the first message, it sends the above-mentioned configuration update information to the access network device. Step 1004A can be replaced by: when the relay node does not receive the third removal indication information within the second preset time period after determining that trigger condition #1 is met, it sends configuration update information to the access network device. Optionally, when the relay node receives the third removal indication information within the second preset time period after determining that the above-mentioned trigger condition #1 is met, it does not need to send configuration update information to the access network device.

[0314] 1005A. The access network device updates the IP address of the relay node it maintains to the IP address of the relay node under the target host node based on the configuration update information.

[0315] 1004B. When the access network device determines to remove the interface between the access network device and the relay node based on the first message, the access network device sends third removal indication information to the relay node.

[0316] Correspondingly, the relay node receives third removal instruction information from the access network device. The third removal instruction information is used to instruct the relay node to remove the interface between the relay node and the access network device. The third removal instruction information may include identification information of the access network device.

[0317] 1005B. In response to the third removal indication information, the relay node initiates a process of removing the interface between the relay node and the access network device.

[0318] In one possible implementation, upon receiving third removal indication information within a first preset time period after sending the first message to the access network device, the relay node initiates a process for removing the interface between the relay node and the access network device. The process for the relay node initiating the process for removing the interface between the relay node and the access network device can be seen in step 402B of Figure 4 . After the relay node initiates the process for removing the interface between the relay node and the access network device, the access network device and the relay node execute the process for removing the interface between the relay node and the access network device (e.g., the Xn interface), see step 403B of Figure 4 .

[0319] In an embodiment of the present application, upon determining that a trigger condition has been met, the relay node sends a first message to the access network device. Based on the first message, the access network device determines whether to maintain the interface with the relay node. The first message does not include configuration update information, thereby reducing the amount of data carried by the first message. If the relay node does not receive third removal indication information within a first preset time period after sending the first message to the access network device, it sends configuration update information to the access network device, allowing the access network device to maintain the interface with the relay node.

[0320] FIG11 is a flow chart of another communication method provided by an embodiment of the present application. In the method flow of FIG11 , the source host node of the relay node determines whether to maintain an interface with the relay node. As shown in FIG11 , the method includes:

[0321] 1101A. The relay node determines that trigger condition #1 is satisfied.

[0322] Step 1101A may refer to step 901A in FIG. 9 .

[0323] 1102A. The relay node sends a first message to its source host node.

[0324] Correspondingly, the source host node receives a first message from the relay node, wherein the first message includes configuration update information and / or identification information of the target host node.

[0325] 1101B. The source host node determines that trigger condition #2 is met.

[0326] Step 1101B may refer to step 901B in FIG. 9 .

[0327] Steps 1101A to 1102A and step 1101B are two parallel solutions. The method flow in FIG11 includes steps 1101A to 1102A or step 1101B.

[0328] 1103. The source host node determines whether to maintain the interface with the relay node.

[0329] In one possible implementation, when the source host node receives the first message, it determines whether to maintain the interface with the relay node based on the first message. In one possible implementation, when the source host node determines that trigger condition #2 is met, it determines whether to maintain the interface with the relay node.

[0330] Exemplarily, the first message includes the configuration update information; the source host node determines to maintain the interface with the relay node when the benefit value of the interface between the source host node and the relay node is greater than or equal to a preset threshold; otherwise, the source host node determines to remove the interface with the relay node. Exemplarily, the first message includes identification information of the target host node of the relay node; the source host node determines to remove the interface with the relay node when the source host node and the target host node cannot communicate via IP routing; otherwise, the source host node determines to maintain the interface with the relay node.

[0331] 1104A. When the source host node determines to remove the interface between the source host node and the relay node, the source host node initiates a process of removing the interface between the source host node and the relay node.

[0332] The source host node initiates the process of removing the interface between the source host node and the relay node, as shown in step 403C in Figure 4. After the source host node initiates the process of removing the interface between the source host node and the relay node, the relay node and the source host node execute the process of removing the interface between the source host node and the relay node, as shown in step 403B in Figure 4. Step 1104A is optional.

[0333] 1104B. When the source host node determines to maintain the interface with the relay node, it updates the IP address of the relay node it maintains to the IP address of the relay node under the target host node.

[0334] Step 1104B is optional.

[0335] 1104C. When the source host node determines to remove the interface between the source host node and the relay node, the source host node sends fifth removal indication information to the relay node.

[0336] Correspondingly, the fifth removal instruction information is used to instruct the relay node to remove the interface between itself and its source host node.

[0337] 1105C. In response to the fifth removal instruction information, the relay node initiates a process of removing the interface between the relay node and its source host node.

[0338] Step 1104C and step 1105C are optional. Step 1104A, step 1104B, and steps 1104C to 1105C are three parallel solutions. The method flow in Figure 11 includes 1104A, step 1104B, or steps 1104C to 1105C.

[0339] In an embodiment of the present application, the source host node determines whether to maintain the interface with the relay node so as to subsequently remove or maintain the interface with the relay node.

[0340] FIG12 is a flow chart of another communication method provided by an embodiment of the present application. In the method flow of FIG12, the source host node of the relay node determines whether to maintain an interface with the relay node. The difference between the method flow of FIG12 and the method flow of FIG11 is that in the method flow of FIG11, the source host node initiates the process of removing the interface between the relay node and the relay node, while in the method flow of FIG12, the relay node initiates the process of removing the interface between the relay node and the access network device. As shown in FIG12, the method includes:

[0341] 1201. The relay node determines that trigger condition #1 is satisfied.

[0342] Step 1201 may refer to step 901A in FIG. 9 .

[0343] 1202. The relay node sends a first message to its source host node.

[0344] Correspondingly, the source host node receives a first message from the relay node, wherein the first message includes identification information of the target host node of the relay node but does not include the configuration update information.

[0345] 1203. The source host node determines whether to maintain the interface with the relay node based on the first message.

[0346] In one possible implementation, upon receiving the first message, the source host node determines, based on the first message, whether to maintain the interface with the relay node. Exemplarily, the first message includes identification information of the target host node of the relay node. If the source host node cannot communicate with the target host node via IP routing, the source host node determines to remove the interface with the relay node; otherwise, the source host node determines to maintain the interface with the relay node.

[0347] 1204A: When the relay node does not receive the fifth removal instruction information within the first preset time period after sending the first message, the relay node sends configuration update information to the source host node.

[0348] Accordingly, when the source host node determines to maintain the interface between it and the relay node based on the first message, it receives configuration update information from the relay node. In one possible implementation, when the source host node determines to maintain the interface between it and the relay node based on the first message, it does not send the fifth removal indication information to the relay node, and the fifth removal indication information is used to instruct the relay node to remove the interface between it and the source host node. Step 1204A can be replaced by: when the relay node does not receive the fifth removal indication information within the second preset time length after determining that the trigger condition #1 is met, the relay node sends configuration update information to the source host node. Optionally, when the relay node receives the fifth removal indication information within the second preset time length after determining that the above-mentioned trigger condition #1 is met, it does not need to send configuration update information to the source host node.

[0349] 1205A. The source host node updates the IP address of the relay node it maintains to the IP address of the relay node under the target host node based on the configuration update information.

[0350] Step 1204A and step 1205A are optional.

[0351] 1204B. When the source host node determines to remove the interface between the source host node and the relay node based on the first message, the source host node sends fifth removal indication information to the relay node.

[0352] Correspondingly, the relay node receives fifth removal instruction information from the source host node. The fifth removal instruction information is used to instruct the relay node to remove the interface between it and its source host node. The third removal instruction information may include identification information of the source host node.

[0353] 1205B. In response to the fifth removal instruction information, the relay node initiates a process of removing the interface between the relay node and the source host node.

[0354] Steps 1204B and 1205B are optional. After the relay node initiates the process of removing the interface between it and the source host node, the source host node and the relay node execute the process of removing the interface (e.g., Xn interface) between them, as shown in step 403B in Figure 4. Steps 1204A to 1205A and steps 1204B to 1205B are two parallel solutions. The method flow in Figure 12 includes steps 1204A to 1205A or steps 1204B to 1205B.

[0355] In an embodiment of the present application, upon determining that a trigger condition has been met, the relay node or target host node sends a first message to the source host node. Based on the first message, the source host node determines whether to maintain the interface with the relay node. The first message does not include configuration update information, thereby reducing the amount of data carried by the first message. If the relay node does not receive third removal indication information within a first preset time period after sending the first message to the source host node, the relay node sends configuration update information to the access network device, thereby enabling the access network device to maintain the interface with the relay node.

[0356] FIG13 is a flow chart of another communication method provided by an embodiment of the present application. In the method flow of FIG13 , the target host node of the relay node determines whether to maintain an interface between the relay node and the access network device. As shown in FIG13 , the method includes:

[0357] 1301. The target host node determines whether the interface between the relay node and the access network device needs maintenance.

[0358] In one possible implementation, the target host node determines whether the interface between the relay node and the access network device requires maintenance based on whether the target host node and the access network device can communicate via IP routing. For example, when the target host node and the access network device cannot communicate via IP routing, it is determined that the interface between the relay node and the access network device does not require maintenance, i.e., it is determined that the interface between the relay node and the access network device is removed; when the target host node and the access network device can communicate via IP routing, it is determined that the interface between the relay node and the access network device requires maintenance, i.e., it is determined that the interface between the relay node and the access network device is maintained.

[0359] In one possible implementation, the target host node determines whether the interface between the relay node and the access network device requires maintenance based on whether the target host node has an interface with the access network device. For example, if the target host node has an interface with the access network device, the interface between the relay node and the access network device is determined to require maintenance; if the target host node does not have an interface with the access network device, the interface between the relay node and the access network device is determined to not require maintenance.

[0360] In one possible implementation, the target host node determines whether the interface between the relay node and the access network device requires maintenance based on the revenue value of the interface between the target host node and the access network device. For example, when the revenue value of the interface between the target host node and the access network device is greater than or equal to a preset threshold, the interface between the relay node and the access network device is determined to require maintenance; otherwise, the interface between the relay node and the access network device is determined to not require maintenance. The preset threshold can be set according to actual needs and is not limited in this application.

[0361] 1302A. When the target host node determines that the interface between the relay node and the access network device needs maintenance, the target host node sends an RRC message carrying maintenance indication information to the relay node.

[0362] Accordingly, the relay node receives an RRC message carrying maintenance indication information from the target host node. If the MT has not yet been handed over, this RRC message is sent by the source host node, for example, via a handover command. The maintenance indication information instructs the relay node to maintain the interface with the access network device. The maintenance indication information may include the identification information of the access network device or the IP address of the access network device.

[0363] 1303A. In response to the maintenance instruction information, the relay node sends configuration update information to the access network device.

[0364] Accordingly, the access network device receives configuration update information from the relay node. The configuration update information includes the IP address of the relay node under the target host node and, optionally, the relay node's identification information and / or the IP address of the relay node under its source host node. The configuration update information is used to maintain the interface between the relay node and the access network device.

[0365] 1304A: The access network device updates the IP address of the relay node maintained by itself to the IP address of the relay node under the target host node based on the configuration update information.

[0366] Steps 1302A to 1304A are optional.

[0367] 1302B. The relay node establishes an Xn interface with the target host node.

[0368] In one possible implementation, the MT has completed handover or cross-site RRC re-establishment, and the WAB-gNB establishes an Xn interface with the target host node.

[0369] 1303B. When the target host node determines that the interface between the relay node and the access network device needs maintenance, the target host node sends an XnAP message carrying maintenance indication information to the relay node.

[0370] Accordingly, the relay node receives an XnAP message carrying maintenance indication information from the target host node. In one possible implementation, the MT has completed handover or cross-site RRC re-establishment, and the relay node has established an Xn interface with the target host node. Upon determining that the interface between the relay node and the access network device requires maintenance, the target host node sends an XnAP message carrying maintenance indication information to the relay node.

[0371] 1304B. In response to the maintenance instruction information, the relay node sends configuration update information to the access network device.

[0372] 1305B. The access network device updates the IP address of the relay node maintained by itself to the IP address of the relay node under the target host node based on the configuration update information.

[0373] Steps 1304B to 1305B may refer to steps 1303A to 1304A. Steps 1302B to 1305B are optional.

[0374] 1302C. When the target host node determines that the interface between the relay node and the access network device needs maintenance, the target host node sends configuration update information to the access network device.

[0375] Correspondingly, the access network device receives the configuration update information from the target host node.

[0376] 1303C. The access network device updates the IP address of the relay node maintained by itself to the IP address of the relay node under the target host node based on the configuration update information.

[0377] Steps 1302C to 1303C are optional.

[0378] 1302D. When the target host node determines that the interface between the relay node and the access network device needs to be removed, the target host node sends an RRC message carrying fourth removal indication information to the relay node.

[0379] Accordingly, the relay node receives an RRC message from the target host node carrying fourth removal indication information. The fourth removal indication information is used to instruct the relay node to remove the interface between the relay node and the access network device. The fourth removal indication information may include identification information of the access network device or the IP address of the access network device. If the MT has not yet been handed over, this RRC message is sent by the source host node, for example, via a handover command.

[0380] 1303D. In response to the fourth removal indication information, the relay node initiates a process of removing the interface between the relay node and the access network device.

[0381] The process for the relay node to initiate the removal of the interface between the relay node and the access network device can be seen in step 402B of Figure 4 . After the relay node initiates the process for removing the interface between the relay node and the access network device, the access network device and the relay node execute the process for removing the interface (e.g., the Xn interface) between them, as shown in step 403B of Figure 4 . Steps 1302D to 1303D are optional.

[0382] 1302E. The relay node establishes an Xn interface with the target host node.

[0383] 1303E: When the target host node determines that the interface between the relay node and the access network device needs to be removed, the target host node sends a message carrying fourth removal indication information XnAP to the relay node.

[0384] In one possible implementation, the MT has completed switching or cross-site RRC re-establishment, and the relay node establishes an Xn interface with the target host node; when the target host node determines that the interface between the relay node and the access network device needs to be removed, it sends a message carrying the fourth removal indication information XnAP to the relay node.

[0385] 1304E: In response to the fourth removal indication information, the relay node initiates a process of removing the interface between the relay node and the access network device.

[0386] 1302F. When the target host node determines that the interface between the relay node and the access network device needs to be removed, the target host node sends first removal indication information to the access network device.

[0387] Accordingly, the access network device receives first removal instruction information from the target host node. The first removal instruction information is used to instruct the access network device to remove the interface between the access network device and the relay node. The first removal instruction information may include identification information of the relay node or the IP address of the relay node under the source host node.

[0388] 1303F. In response to the first removal instruction information, the access network device initiates a process of removing the interface between the access network device and the relay node.

[0389] After the access network device initiates the process of removing the interface between the access network device and the relay node, the access network device and the relay node execute the process of removing the interface (eg, Xn interface) therebetween, see step 403B in Figure 4. Steps 1302D to 1303D are optional.

[0390] Steps 1302A to 1304A, 1302B to 1305B, 1302C to 1303C, 1302D to 1303D, 1302E to 1304E, and 1302F to 1303F are six parallel schemes. The method flow in FIG13 includes steps 1302A to 1304A, 1302B to 1305B, 1302C to 1303C, 1302D to 1303D, 1302E to 1304E, or 1302F to 1303F.

[0391] In an embodiment of the present application, upon determining that the interface between the relay node and the access network device requires maintenance, the target host node sends maintenance instruction information to the relay node and / or sends configuration update information to the access network device to maintain the interface between the relay node and the access network device; this can solve the problem of how to maintain the interface between the relay node and the access network device. Upon determining that the interface between the relay node and the access network device requires maintenance, the target host node sends fourth removal instruction information to the relay node and / or sends first removal instruction information to the access network device; this can save resource overhead for maintaining the interface between the relay node and the access network device.

[0392] FIG14 is a flow chart of another communication method provided by an embodiment of the present application. In the method flow of FIG14 , the target host node of the relay node determines whether to maintain an interface between the relay node and the source host node. As shown in FIG14 , the method includes:

[0393] 1401. The target host node determines whether the interface between the relay node and the source host node needs maintenance.

[0394] In one possible implementation, the target host node determines whether the interface between the relay node and the source host node needs to be maintained based on whether the target host node and the source host node can communicate via IP routing. For example, when the target host node and the source host node cannot communicate via IP routing, it is determined that the interface between the relay node and the source host node does not need to be maintained, that is, it is determined to remove the interface between the relay node and the source host node; when the target host node and the source host node can communicate via IP routing, it is determined that the interface between the relay node and the source host node needs to be maintained, that is, it is determined to maintain the interface between the relay node and the source host node.

[0395] In one possible implementation, the target host node determines whether the interface between the relay node and the source host node requires maintenance based on whether the target host node has an interface with the source host node. For example, when an interface exists between the target host node and the source host node, the interface between the relay node and the source host node is determined to require maintenance; when no interface exists between the target host node and the source host node, the interface between the relay node and the source host node is determined to not require maintenance.

[0396] In one possible implementation, the target host node determines whether the interface between the relay node and the source host node requires maintenance based on the benefit value of the interface between the target host node and the source host node. For example, when the benefit value of the interface between the target host node and the source host node is greater than or equal to a preset threshold, the interface between the relay node and the source host node is determined to require maintenance; otherwise, the interface between the relay node and the source host node is determined to not require maintenance. The preset threshold can be set according to actual needs and is not limited in this application.

[0397] 1402A. When the target host node determines that the interface between the relay node and the source host node needs maintenance, the target host node sends an RRC message carrying maintenance indication information to the relay node.

[0398] Accordingly, the relay node receives an RRC message carrying maintenance indication information from the target host node. If the MT has not yet switched, this RRC message is sent by the source host node, for example, via a handover command. The maintenance indication information instructs the relay node to maintain the interface with the source host node. The maintenance indication information may include the identification information of the source host node or the IP address of the source host node.

[0399] 1403A. In response to the maintenance indication information, the relay node sends configuration update information to the source host node.

[0400] Accordingly, the source host node receives configuration update information from the relay node. The configuration update information includes the IP address of the relay node under the target host node and, optionally, the relay node's identification information and / or the IP address of the relay node under its source host node. The configuration update information is used to maintain the interface between the relay node and the source host node.

[0401] 1404A. The source host node updates the IP address of the relay node it maintains to the IP address of the relay node under the target host node based on the configuration update information.

[0402] Steps 1402A to 1404A are optional.

[0403] 1402B. The relay node establishes an Xn interface with the target host node.

[0404] In one possible implementation, the MT has completed handover or cross-site RRC re-establishment, and the WAB-gNB establishes an Xn interface with the target host node.

[0405] 1403B. When the target host node determines that the interface between the relay node and the source host node needs maintenance, the target host node sends an XnAP message carrying maintenance indication information to the relay node.

[0406] Accordingly, the relay node receives an XnAP message carrying maintenance indication information from the target host node. In one possible implementation, the MT has completed handover or cross-site RRC re-establishment, and the relay node has established an Xn interface with the target host node. Upon determining that the interface between the relay node and the source host node requires maintenance, the target host node sends an XnAP message carrying maintenance indication information to the relay node.

[0407] 1404B. In response to the maintenance indication information, the relay node sends configuration update information to the source host node.

[0408] 1405B. The source host node updates the IP address of the relay node it maintains to the IP address of the relay node under the target host node based on the configuration update information.

[0409] Steps 1404B to 1405B may refer to steps 1403A to 1404A. Steps 1402B to 1405B are optional.

[0410] 1402C. When the target host node determines that the interface between the relay node and the source host node needs maintenance, the target host node sends configuration update information to the source host node.

[0411] Accordingly, the source host node receives the configuration update information from the target host node.

[0412] 1403C. The source host node updates the IP address of the relay node it maintains to the IP address of the relay node under the target host node based on the configuration update information.

[0413] Steps 1402C to 1403C are optional.

[0414] 1402D. When the target host node determines that the interface between the relay node and the source host node needs to be removed, the target host node sends an RRC message carrying fifth removal indication information to the relay node.

[0415] Accordingly, the relay node receives an RRC message from the target host node carrying fifth removal indication information. The fifth removal indication information is used to instruct the relay node to remove the interface between the relay node and the source host node. The fifth removal indication information may include identification information of the source host node or the IP address of the source host node. If the MT has not yet been handed over, this RRC message is sent by the source host node, for example, via a handover command.

[0416] 1403D. In response to the fifth removal instruction information, the relay node initiates a process of removing the interface between the relay node and the source host node.

[0417] The process of the relay node initiating the removal of the interface between the relay node and the source host node can be seen in step 402B of Figure 4. After the relay node initiates the process of removing the interface between the relay node and the source host node, the source host node and the relay node execute the process of removing the interface (e.g., the Xn interface) between them, see step 403B of Figure 4. Steps 1402D to 1403D are optional.

[0418] 1402E. The relay node establishes an Xn interface with the target host node.

[0419] 1403E: When the target host node determines that the interface between the relay node and the source host node needs to be removed, the target host node sends a message carrying fifth removal indication information XnAP to the relay node.

[0420] In one possible implementation, the MT has completed handover or cross-site RRC re-establishment, and the relay node establishes an Xn interface with the target host node; when the target host node determines that the interface between the relay node and the source host node needs to be removed, it sends a message carrying the fifth removal indication information XnAP to the relay node.

[0421] 1404E: In response to the fifth removal instruction information, the relay node initiates a process of removing the interface between the relay node and the source host node.

[0422] 1402F. When the target host node determines that the interface between the relay node and the source host node needs to be removed, the target host node sends second removal indication information to the source host node.

[0423] Correspondingly, the source host node receives second removal instruction information from the target host node. The second removal instruction information is used to instruct the source host node to remove the interface between the source host node and the relay node. The second removal instruction information may include identification information of the relay node or the IP address of the relay node under the source host node.

[0424] 1403F. In response to the second removal indication information, the source host node initiates a process of removing the interface between the source host node and the relay node.

[0425] After the source host node initiates the process of removing the interface between the source host node and the relay node, the source host node and the relay node execute the process of removing the interface (eg, Xn interface) between them, see step 403B in Figure 4. Steps 1402D to 1403D are optional.

[0426] Steps 1402A to 1404A, 1402B to 1405B, 1402C to 1403C, 1402D to 1403D, 1402E to 1404E, and 1402F to 1403F are six parallel schemes. The method flow in FIG14 includes steps 1402A to 1404A, 1402B to 1405B, 1402C to 1403C, 1402D to 1403D, 1402E to 1404E, or 1402F to 1403F.

[0427] In an embodiment of the present application, upon determining that the interface between the relay node and the source host node requires maintenance, maintenance indication information is sent to the relay node, and / or configuration update information is sent to the source host node to maintain the interface between the relay node and the source host node; this can solve the problem of how to maintain the interface between the relay node and the source host node. Upon determining that the interface between the relay node and the source host node requires maintenance, the target host node sends fifth removal indication information to the relay node, and / or second removal indication information to the source host node; this can save resource overhead for maintaining the interface between the relay node and the source host node.

[0428] Before determining whether the interface between the relay node and the access network device needs maintenance, the target host node may first obtain the identification information of the access network device. That is, before executing the operations in the method flow of Figure 13, the target host node needs to first obtain the identification information of the access network device. Before determining whether the interface between the relay node and the source host node needs maintenance, the target host node may first obtain the identification information of the source host node. That is, before executing the operations in the method flow of Figure 14, the target host node needs to first obtain the identification information of the source host node. The following introduces several possible ways for the target host node to obtain the identification information of the access network device and / or the identification information of the source host node in combination with Figures 15, 16 and 17. Figure 15 is a flow chart of another communication method provided in an embodiment of the present application. In the method flow of Figure 15, when the source host node determines that trigger condition #2 is met, it sends a second message to the target host node so that the target host node obtains the identification information of the access network device and / or the identification information of the source host node. As shown in Figure 15, the method includes:

[0429] 1501. The source host node determines that trigger condition #2 is met.

[0430] Step 1501 may refer to step 901B in FIG. 9 .

[0431] 1502. When the source host node determines that trigger condition #2 is met, the source host node sends a second message to the target host node.

[0432] Accordingly, the target host node receives the second message. The second message includes identification information of the access network device and / or identification information of the source host node. In the present application, the access network device refers to a device that has an interface with the relay node. Exemplarily, the identification information of an access network device includes the gNB ID and / or IP address of the access network device. Optionally, the second message also includes information for indicating that the access network device is a device that has an interface with the relay node. Exemplarily, the second message includes identification information of one or more access network devices that have an interface with the relay node and / or identification information of the source host node. The trigger condition for the target host node to determine whether the interface between the relay node and the source host node needs to be maintained is that the target host node receives the second message.

[0433] In one possible implementation, the source host node determines that the MT is to perform Xn handover (i.e., the MT does not change the AMF network element), and the second message may be a handover request message transmitted through the Xn interface. In one possible implementation, if the MT is to perform NG handover (i.e., there is no Xn interface between the source host node and the target host node, or the MT needs to replace the AMF network element), the second message may be a handover request (HANDOVER REQUIRED) message sent by the source host node to the AMF network element and a handover request (HANDOVER REQUEST) message sent by the AMF network element to the target host node. In one possible implementation, the source host node determines that the MT is performing RRC re-establishment under a new base station (i.e., the target host node), and the second message sent by the source host node may be a UE CONTEXT RETRIEVE RESPONSE) message sent to the target host node.

[0434] 1503. The target host node obtains identification information of the access network device and / or identification information of the source host node based on the second message.

[0435] In an embodiment of the present application, when the source host node determines that trigger condition #2 is met, it sends a second message to the target host node; this allows the target host node to obtain identification information of the access network device and / or identification information of the source host node.

[0436] FIG16 is a flow chart of another communication method provided by an embodiment of the present application. The difference between the method flow of FIG16 and the method flow of FIG15 is that the relay node sends a message to its source host node, and the message carries the identification information of the access network device that has an interface with the relay node. As shown in FIG16, the method includes:

[0437] 1601. The relay node determines that its MT will be handed over.

[0438] 1602A. The MT of the relay node sends an RRC message carrying identification information of the access network device to its source host node.

[0439] Accordingly, the source host node receives the RRC message carrying the identification information of the access network device. Exemplarily, the RRC message sent by the MT of the relay node to its source host node carries the identification information of one or more access network devices having interfaces with the relay node.

[0440] 1602B. The relay node sends an XnAP message carrying identification information of the access network device to its source host node.

[0441] Accordingly, the source host node receives an XnAP message from the relay node that carries the identification information of the access network device. Exemplarily, the WAB-gNB (i.e., the base station functional portion of the relay node) sends an XnAP message to its source host node, carrying the identification information of one or more access network devices that interface with the relay node. Steps 1602A and 1602B are two parallel solutions. The method flow in Figure 16 includes either step 1602A or step 1602B.

[0442] 1603. The source host node determines that the MT has completed the handover.

[0443] Step 1603 is optional.

[0444] 1604. The source host node sends a second message to the target host node.

[0445] Correspondingly, the target host node receives the second message. Step 1604 can refer to step 1502 in FIG. 15 .

[0446] In an embodiment of the present application, the source host node sends a second message to the target host node; this allows the target host node to obtain identification information of the access network device and / or identification information of the source host node.

[0447] FIG17 is a flow chart of another communication method provided by an embodiment of the present application. The difference between the method flow of FIG17 and the method flow of FIG15 and FIG16 is that the relay node sends a message to its target host node, and the message carries the identification information of the access network device and / or the identification information of the source host node. As shown in FIG17, the method includes:

[0448] 1701. The relay node determines that the MT has been switched to the target host node or that the RRC re-establishment of the MT under the target host node is completed.

[0449] For example, when the relay node successfully randomly accesses the target host node, it is determined that the MT has been handed over to the target host node. For another example, when the relay node sends an RRC Reestablishment Complete message to the target host node, it is determined that the RRC reestablishment of the MT under the target host node is completed.

[0450] 1702. The relay node establishes an Xn interface with the target host node.

[0451] Step 1702 is optional.

[0452] 1703A. The MT of the relay node sends an RRC message to its target donor node.

[0453] Accordingly, the target host node receives an RRC message from the MT of the relay node, which includes identification information of one or more access network devices having interfaces with the relay node and / or identification information of the source host node of the relay node.

[0454] 1703B. The relay node sends an XnAP message to its target host node.

[0455] Accordingly, the target host node receives an XnAP message from the relay node. This XnAP message carries identification information of one or more access network devices that interface with the relay node and / or identification information of the source host node of the relay node. Steps 1703A and 1703B are two parallel solutions. The method flow in Figure 17 includes either step 1703A or step 1703B.

[0456] 1704. The target host node obtains identification information of the access network device and / or identification information of the source host node based on the RRC message or XnAP message from the relay node.

[0457] In an embodiment of the present application, the relay node sends a second message to the target host node; this allows the target host node to obtain identification information of the access network device and / or identification information of the source host node.

[0458] This application also provides a solution in which a RAN intelligent controller (RIC) determines whether to maintain the interface between a relay node and access network equipment in an open radio access network (Open RAN, O-RAN) architecture. Figure 18 is a schematic diagram of an O-RAN architecture provided by an embodiment of this application. As shown in Figure 18, the O-RAN architecture includes: RIC, gNB-DU, and gNB-CU. The RIC is responsible for collecting network information and performing necessary optimization tasks. It communicates with the gNB-CU and gNB-DU via the E2 interface. That is, the O-RIC can directly control the gNB-DU or control the gNB-DU through the gNB-CU. gNB-CU: A gNB-CU that supports O-RAN functions, including the donor base station CU (donor-CU) and WAB-CU. gNB-DU: A gNB-DU that supports O-RAN functions, including the donor base station DU (donor-DU) and WAB-DU. The donor-CU and donor-DU communicate via the F1 interface. The donor-DU and WAB-MT communicate via the Uu interface. The interaction between WAB and donor (host node) can be performed through RIC, and related information (such as bearer mapping) can also be generated by RIC.

[0459] FIG19 is a flow chart of another communication method provided by an embodiment of the present application. In the method flow of FIG19 , the RIC determines whether to maintain the interface between the relay node and the access network device. As shown in FIG19 , the method includes:

[0460] 1901A. The relay node sends an E2 message to the RIC.

[0461] Accordingly, the RIC receives an E2 message from the relay node. An E2 message is a message sent via the E2 interface. An E2 message includes configuration update information and / or identification information of the target host node. In one possible implementation, upon determining that trigger condition #1 (see step 901A in FIG. 9 ) is met, the relay node sends an E2 message to the RIC.

[0462] 1901B. The source host node sends an E2 message to the RIC.

[0463] Accordingly, the RIC receives the E2 message from the source host node. In one possible implementation, the source host node sends the E2 message to the RIC when determining that trigger condition #2 (see step 901B in FIG9 ) is satisfied.

[0464] 1901C. The target host node sends an E2 message to the RIC.

[0465] Accordingly, the RIC receives the E2 message from the target host node. In one possible implementation, the target host node sends the E2 message to the RIC when determining that trigger condition #2 (see step 801 in FIG8 ) is satisfied.

[0466] 1902. The RIC determines the interface between the relay node and the access network device that needs to be maintained and / or removed.

[0467] The RIC already knows which access network devices have Xn interfaces between the WAB-gNB and the RIC determines which of these Xn interfaces need to be maintained and / or removed.

[0468] 1903A. RIC sends an E2 message to one or more access network devices.

[0469] Accordingly, one or more access network devices receive an E2 message from the RIC. The E2 message includes identification information of the relay node and / or the IP address of the relay node under the source host node. The E2 message is used to instruct the access network device to remove the interface between the access network device and the relay node. The interfaces between one or more access network devices and the relay node in step 1903A are interfaces that need to be removed. Exemplarily, the RIC determines that the interface between the relay node and access network device #1 and the interface between the relay node and access network device #2 need to be removed; the RIC sends an E2 message #1 to access network device #1 and an E2 message #2 to access network device #2. E2 message #1 is used to instruct access network device #1 to remove the interface between the relay node, and E2 message #2 is used to instruct access network device #2 to remove the interface between the relay node. For interfaces with relay nodes that are not instructed to be removed, the access network device retains the interface with the relay node by default. That is, if an access network device does not receive an E2 message instructing it to remove the interface between the relay node, the access network device retains the interface with the relay node. In FIG19 , the access network devices represent various access network devices that have interfaces with the relay nodes.

[0470] 1904A. One or more access network devices initiate a process of removing an interface with a relay node.

[0471] After the access network device initiates the process of removing the interface between the access network device and the relay node, the access network device and the relay node execute the process of removing the interface (e.g., Xn interface) between them, see step 403B in Figure 4. Exemplarily, the access network device initiates the process of removing the interface between the access network device and the relay node in response to an E2 message instructing the access network device to remove the interface between the access network device and the relay node.

[0472] 1905A. RIC sends an E2 message to the relay node.

[0473] Correspondingly, the relay node receives an E2 message from the RIC. The E2 message is used to indicate the interfaces between the relay node and each access network device that need to be maintained.

[0474] 1906A. The relay node sends configuration update information to one or more access network devices.

[0475] Accordingly, one or more access network devices receive configuration update information from the relay node. The interfaces between the one or more access network devices and the relay node in step 1906A are interfaces that require maintenance. The configuration update information includes the IP address of the relay node under the target host node and, optionally, identification information of the relay node and / or the IP address of the relay node under the source host node.

[0476] 1907A. The access network device updates the IP address of the relay node it maintains to the IP address of the relay node under the target host node based on the configuration update information.

[0477] 1903B. The RIC sends an E2 message to the relay node.

[0478] Accordingly, the relay node receives an E2 message from the RIC. The E2 message is used to indicate the interfaces between the relay node and each access network device that need to be removed and / or maintained. The E2 message may include identification information of the access network devices associated with one or more interfaces that need to be removed, and / or identification information of the access network devices associated with one or more interfaces that need to be maintained. Exemplarily, the E2 message includes first indication information and second indication information, the first indication information is used to indicate that the interface between access network device #1 and the relay node and the interface between access network device #2 and the relay node need to be removed, and the second indication information is used to indicate that the interface between access network device #3 and the relay node and the interface between access network device #4 and the relay node need to be maintained.

[0479] 1904B. The relay node initiates a process of removing interfaces between the relay node and one or more access network devices.

[0480] In step 1904B, one or more interfaces between access network devices and the relay node are interfaces that need to be removed. Step 1904B is optional. For example, the E2 message in step 1903B indicates that the interface between access network device #1 and the relay node and the interface between access network device #2 and the relay node need to be removed; the relay node initiates the process of removing the interface between access network device #1 and the relay node, and the process of removing the interface between access network device #2 and the relay node.

[0481] 1905B. The relay node sends configuration update information to one or more access network devices.

[0482] Accordingly, one or more access network devices receive configuration update information from the relay node. Step 1905B is optional. In step 1905B, one or more interfaces between the access network devices and the relay node are interfaces that require maintenance. For example, the E2 message in step 1903B indicates that the interface between access network device #3 and the relay node and the interface between access network device #4 and the relay node require maintenance; the relay node sends configuration update information to access network device #3 and access network device #4, respectively.

[0483] 1906B. The access network device updates the IP address of the relay node it maintains to the IP address of the relay node under the target host node based on the configuration update information.

[0484] 1903C. RIC sends an E2 message to the relay node.

[0485] Correspondingly, the relay node receives an E2 message from the RIC. The E2 message is used to indicate the interfaces between the relay node and each access network device that need to be removed.

[0486] 1904C. The relay node initiates a process of removing interfaces with one or more access network devices.

[0487] Step 1904C may refer to step 1904B.

[0488] 1903D: When the relay node does not receive the third removal indication information within the first preset time period after sending the E2 message to the RIC, it sends configuration update information to the access network device.

[0489] The E2 message in step 1901A does not include configuration update information. Exemplarily, when the relay node does not receive the third removal indication information within a first preset time period after sending the E2 message (i.e., the E2 message in step 1901A) to the RIC, it sends configuration update information to the access network device with which it has an interface.

[0490] 1904D: Based on the configuration update information, the access network device updates the IP address of the relay node it maintains to the IP address of the relay node under the target host node.

[0491] Steps 1903A to 1907A, 1903B to 1906B, 1903C to 1904C, and 1903D to 1904D are four parallel schemes. The method flow of FIG19 may include steps 1903A to 1907A, 1903B to 1906B, 1903C to 1904C, or 1903D to 1904D.

[0492] In the embodiment of the present application, the RIC determines whether to maintain the interface between the relay node and the access network device, and solves the Xn interface maintenance problem during the WAB movement process, thereby supporting the mobility of the WAB.

[0493] It should be understood that in the various embodiments of the present application, unless otherwise specified and there is no logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships. In the above embodiment, taking an access network device as an example, a scheme for removing or maintaining the interface between the relay node and the access network device is described. In actual applications, the scheme for removing the interface between the relay node and the access network device and the scheme for maintaining the interface between the relay node and the access network device can be combined. For example, the interface between the relay node and a part of the access network device can be removed in the manner described in any of the above embodiments, and the interface between the relay node and another part of the access network device can be maintained in the manner described in any of the above embodiments. In addition, the scheme for removing or maintaining the interface between the relay node and the access network device can also be combined with the scheme for removing or maintaining the interface between the relay node and the source host node.

[0494] It should also be understood that in some of the above embodiments, devices in existing network architectures are mainly used as examples for illustrative purposes, and it should be understood that the embodiments of the present application do not limit the specific form of the devices. For example, devices that can achieve the same functions in the future are applicable to the embodiments of the present application.

[0495] It can be understood that in the above-mentioned method embodiments, the methods and operations implemented by devices (such as relay nodes, source host nodes, target host nodes, access network devices) can also be implemented by components that can be used in devices (such as chips or circuits).

[0496] It can also be understood that some optional features in the various embodiments of the present application may not depend on other features in certain scenarios, and may also be combined with other features in certain scenarios, without limitation.

[0497] Those skilled in the art should be aware that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is performed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0498] The following describes the structure of a communication device that can implement the communication method provided in the embodiment of the present application in conjunction with the accompanying drawings. The following only briefly describes the communication device. For details on the implementation of the solution, please refer to the description of the method embodiment above, which will not be repeated below.

[0499] Figure 20 is a schematic diagram of the structure of a communication device 2000 provided in an embodiment of the present application. The communication device 2000 can implement the functions or steps implemented by the relay node in each of the above-mentioned method embodiments, the functions or steps implemented by the source host node in each of the above-mentioned method embodiments, the functions or steps implemented by the target host node in each of the above-mentioned method embodiments, or the functions or steps implemented by the access network device in each of the above-mentioned method embodiments. The communication device may include a processing module 2010 and a transceiver module 2020. In one possible implementation, it may also include a storage unit that can be used to store instructions (code or program) and / or data. The processing module 2010 and the transceiver module 2020 can be coupled to the storage unit. For example, the processing module 2010 can read the instructions (code or program) and / or data in the storage unit to implement the corresponding method. The above-mentioned units can be provided independently or partially or fully integrated. For example, the transceiver module 2020 may include a transmitting module and a receiving module. The transmitting module can be a transmitter, and the receiving module can be a receiver. The entity corresponding to the transceiver module 2020 may be a transceiver circuit, such as a transceiver or a communication interface.

[0500] In some possible implementations, the communication device 2000 can implement the behaviors and functions of the relay node in the above-described method embodiments. For example, the communication device 2000 can be a relay node, or a component (e.g., a chip or circuit) used in a relay node. The transceiver module 2020 can, for example, be used to perform all receiving or sending operations performed by the relay node in the embodiments of Figures 4 to 17 and 19. The processing module 2010 can, for example, be used to perform all operations performed by the relay node in the embodiments of Figures 4 to 17 and 19 except for the transmitting and receiving operations.

[0501] In some possible implementations, the communication device 2000 can implement the behaviors and functions of the source host node in the above-mentioned method embodiments. For example, the communication device 2000 can be a source host node, or a component (such as a chip or circuit) applied to the source host node. The transceiver module 2020 can be used to perform all receiving or sending operations performed by the source host node in the embodiments of Figures 4 to 17 and 19. The processing module 2010 can be used to perform all operations except the transceiver operations performed by the source host node in the embodiments of Figures 4 to 17 and 19.

[0502] In some possible implementations, the communication device 2000 can implement the behaviors and functions of the target host node in the above-mentioned method embodiments. For example, the communication device 2000 can be a target host node, or it can be a component (such as a chip or circuit) applied to the target host node. The transceiver module 2020 can be used to perform all receiving or sending operations performed by the target host node in the embodiments of Figures 4 to 17 and 19. The processing module 2010 can be used to perform all operations except the receiving and sending operations performed by the target host node in the embodiments of Figures 4 to 17 and 19.

[0503] In some possible implementations, the communication device 2000 can implement the corresponding behaviors and functions of the access network device in the above-mentioned method embodiments. For example, the communication device 2000 can be an access network device, or it can be a component (such as a chip or circuit) used in the access network device. The transceiver module 2020 can be used to perform all receiving or sending operations performed by the access network device in the embodiments of Figures 4 to 17 and 19. The processing module 2010 can be used to perform all operations performed by the access network device in the embodiments of Figures 4 to 17 and 19 except for the receiving and sending operations.

[0504] FIG21 is a schematic diagram of the structure of another apparatus 210 provided in an embodiment of the present application. The apparatus in FIG21 can be the aforementioned relay node or a chip for the aforementioned relay node, the aforementioned source host node or a chip for the aforementioned source host node, the aforementioned target host node or a chip for the aforementioned target host node, or the aforementioned access network device or a chip for the aforementioned access network device. As shown in FIG21 , the apparatus 210 includes a processing circuit 2110 and a transceiver circuit 2120.

[0505] In some embodiments of the present application, the processing circuit 2110 and the transceiver circuit 2120 may be configured to execute functions or operations performed by a relay node. The transceiver circuit 2120 may be configured to, for example, execute all receiving or transmitting operations performed by the relay node in the embodiments of Figures 4 to 17 and 19. The processing circuit 2110 may be configured to, for example, execute all operations performed by the relay node in the embodiments of Figures 4 to 17 and 19 except for the transceiver operations.

[0506] In some embodiments of the present application, the processing circuit 2110 and the transceiver circuit 2120 may be configured to execute functions or operations performed by the source host node. The transceiver circuit 2120 may be configured to, for example, execute all receiving or sending operations performed by the source host node in the embodiments of Figures 4 to 17 and 19. The processing circuit 2110 may be configured to, for example, execute all operations except the transceiver operations performed by the source host node in the embodiments of Figures 4 to 17 and 19.

[0507] In some embodiments of the present application, the processing circuit 2110 and the transceiver circuit 2120 may be configured to execute functions or operations performed by the target host node. The transceiver circuit 2120 may be configured to, for example, execute all receiving or sending operations performed by the target host node in the embodiments of Figures 4 to 17 and 19. The processing circuit 2110 may be configured to, for example, execute all operations except the transceiver operations performed by the target host node in the embodiments of Figures 4 to 17 and 19.

[0508] In some embodiments of the present application, the processing circuit 2110 and the transceiver circuit 2120 may be configured to execute functions or operations performed by the access network device. The transceiver circuit 2120 may, for example, be configured to execute all receiving or transmitting operations performed by the access network device in the embodiments of Figures 4 to 17 and 19. The processing circuit 2110 may, for example, be configured to execute all operations performed by the access network device in the embodiments of Figures 4 to 17 and 19 except for the transceiver operations.

[0509] In a possible implementation, the transceiver circuit 2120 includes at least one transceiver, and the processing circuit 2110 includes at least one processor, or a circuit in at least one processor for processing or control.

[0510] The transceiver is used to communicate with other devices / apparatuses via a transmission medium. The processor uses the transceiver to transmit and receive data and / or signaling and is used to implement the methods in the above-described method embodiments. The processor can implement the functions of the processing module 2010, and the transceiver can implement the functions of the transceiver module 2020. Optionally, the transceiver may include a radio frequency circuit and an antenna. The radio frequency circuit is primarily used for converting baseband signals into radio frequency signals and processing radio frequency signals. The antenna is primarily used for transmitting and receiving radio frequency signals in the form of electromagnetic waves.

[0511] Optionally, the device 210 may further include at least one memory for storing program instructions and / or data. The memory and the processor are coupled. The coupling in the embodiments of the present application is an indirect coupling or communication connection between devices, units, or modules, which may be electrical, mechanical, or other forms, and is used for information exchange between the devices, units, or modules. The processor may operate in conjunction with the memory. The processor may execute program instructions stored in the memory. At least one of the at least one memory may be included in the processor.

[0512] The processor can read software programs in the memory, interpret and execute the instructions of the software programs, and process the data of the software programs. When data needs to be transmitted wirelessly, the processor performs baseband processing on the data to be transmitted and outputs the baseband signal to the radio frequency circuit. The radio frequency circuit performs radio frequency processing on the baseband signal and then transmits the radio frequency signal to the outside in the form of electromagnetic waves via the antenna. When data is sent to the device 210, the radio frequency circuit receives the radio frequency signal via the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor. The processor converts the baseband signal into data and processes the data.

[0513] In another implementation, the RF circuit and antenna may be arranged independently of the processor performing baseband processing. For example, in a distributed scenario, the RF circuit and antenna may be arranged remotely from the device 210 .

[0514] The specific connection medium between the above-mentioned transceiver, processor and memory is not limited in the embodiments of the present application.

[0515] In the embodiments of the present application, the processor may be one of the following devices: a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or all or part of the circuits used for processing functions in the aforementioned devices, which may implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the method disclosed in conjunction with the embodiments of the present application may be directly embodied as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0516] In one possible implementation, the processing circuit 2110 includes at least one logic circuit, and the transceiver circuit 2120 includes at least one interface. The processing module 2010 in Figure 20 can be implemented using a logic circuit, and the transceiver module 2020 in Figure 20 can be implemented using an interface. The logic circuit can be a chip, a processing circuit, an integrated circuit, or a system on chip (SoC) chip, and the interface can be a communication interface, an input / output interface, etc. In the embodiment of the present application, the logic circuit and the interface can also be coupled to each other. The embodiment of the present application does not limit the specific connection method of the logic circuit and the interface.

[0517] The present application also provides a computer-readable storage medium, in which a computer program or instruction is stored. When the computer program or instruction is executed on a computer, the computer executes the method of the above embodiment.

[0518] The present application also provides a computer program product, which includes instructions or a computer program. When the instructions or the computer program are run on a computer, the method in the above embodiment is executed.

[0519] The present application also provides a communication system, comprising the above relay node, the above source host node and the above target host node. Optionally, the communication system further comprises the above access network device.

[0520] The present application also provides a chip, which includes: a communication interface and a processor; the communication interface is used for sending and receiving signals of the above-mentioned chip; the processor is used to execute computer program instructions so that the communication device including the above-mentioned chip executes the method in the above-mentioned embodiment.

[0521] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0522] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

Claims

1. A communication method, characterized in that: The method is applied to a relay node, and includes: When a trigger condition is met, determining whether to maintain a first interface, where the first interface is an interface between the relay node and the access network device, or the first interface is an interface between the relay node and its source host node, where the trigger condition includes at least one of the following: a mobile terminal MT of the relay node is about to be handed over, the MT has been handed over to a target host node of the relay node, or a radio resource control RRC re-establishment of the MT under the target host node is completed; When it is determined to maintain the first interface, configuration update information is sent to the access network device or the source host node, where the configuration update information includes an Internet Protocol IP address of the relay node under the target host node.

2. The method according to claim 1, characterized in that The method further comprises: When it is determined to remove the first interface, a process of removing the first interface is initiated.

3. A communication method, characterized in that: The method is applied to a relay node, and includes: Determining that a trigger condition is met, the trigger condition including at least one of the following: a mobile terminal MT of the relay node is about to be handed over, the MT has been handed over to a target host node of the relay node, or a radio resource control RRC re-establishment of the MT under the target host node is completed; Initiate a process for removing the first interface or send a first removal indication message to the access network device or send a second removal indication message to the source host node of the relay node, where the first interface is the interface between the relay node and the access network device, or the first interface is the interface between the relay node and its source host node, the first removal indication message is used to instruct the access network device to remove the interface between it and the relay node, and the second removal indication message is used to instruct the source host node to remove the interface between it and the relay node.

4. The method according to claim 3, characterized in that The first removal indication information includes identification information of the relay node or the Internet IP address of the relay node under the source host node, and / or the second removal indication information includes identification information of the relay node or the IP address of the relay node under the source host node.

5. A communication method, characterized in that: The method is applied to a relay node, a source host node of the relay node, or a target host node of the relay node, and includes: Determining that a trigger condition is met, the trigger condition including at least one of the following: a mobile terminal MT of the relay node is about to be handed over, the MT has been handed over to the target host node, the MT is performing radio resource control RRC re-establishment, or the MT has completed RRC re-establishment under the target host node; A first message is sent to the access network device, where the first message includes configuration update information and / or identification information of the target host node, and the configuration update information includes an Internet Protocol IP address of the relay node under the target host node.

6. The method according to claim 5, characterized in that The first message does not include the configuration update information; the method further includes: When no third removal indication information is received within a first preset time period after sending the first message to the access network device, the configuration update information is sent to the access network device, and the third removal indication information is used to instruct the relay node to remove the interface between it and the access network device.

7. A communication method, characterized in that: The method is applied to a relay node, a source host node of the relay node, or a target host node of the relay node, and includes: Determining that a trigger condition is met, the trigger condition including at least one of the following: a mobile terminal MT of the relay node is about to be handed over, the MT has been handed over to the target host node, the MT is performing radio resource control RRC re-establishment, or the MT has completed RRC re-establishment under the target host node; When no third removal indication information is received within a second preset time period after determining that the trigger condition is met, configuration update information is sent to the access network device, wherein the configuration update information includes the Internet Protocol IP address of the relay node under the target host node, and the third removal indication information is used to instruct the relay node to remove the interface between it and the access network device.

8. A communication method, characterized in that: The method is applied to an access network device, and the method includes: receiving a first message, the first message including configuration update information and / or identification information of a target host node of the relay node, the configuration update information including an Internet Protocol (IP) address of the relay node under the target host node; Based on the first message, it is determined whether to maintain the interface with the relay node.

9. The method according to claim 8, characterized in that The first message does not include the configuration update information; the method further includes: When it is determined based on the first message that the interface with the relay node is to be maintained, the configuration update information is received from the relay node.

10. The method according to claim 8 or 9, characterized in that The method further comprises: When determining to maintain the interface with the relay node, the IP address of the relay node maintained by the relay node is updated to the IP address of the relay node under the target host node.

11. The method according to any one of claims 8 to 10, characterized in that The method further comprises: When it is determined to remove the interface with the relay node, a process of removing the interface with the relay node is initiated.

12. A communication method, characterized in that: The method is applied to a source host node or a target host node of a relay node, and the method includes: Determining that a trigger condition is met, the trigger condition including at least one of the following: a mobile terminal MT of the relay node is about to be handed over, the MT has been handed over to the target host node, the MT is performing radio resource control RRC re-establishment, or the MT has completed RRC re-establishment under the target host node; First removal indication information is sent to the access network device, where the first removal indication information is used to instruct the access network device to remove the interface between the access network device and the relay node.

13. The method according to claim 12, characterized in that The first removal instruction information includes identification information of the relay node or the Internet IP address of the relay node under the source host node.

14. A communication method, characterized in that: The method is applied to a target host node of a relay node, and the method includes: Determining whether the interface between the relay node and the access network device requires maintenance; When it is determined that the interface between the relay node and the access network device needs maintenance, maintenance indication information is sent to the relay node, and / or configuration update information is sent to the access network device, the maintenance indication information is used to instruct the relay node to maintain the interface between the relay node and the access network device, and the configuration update information includes the Internet Protocol IP address of the relay node under the target host node.

15. The method according to claim 14, characterized in that The method further comprises: When it is determined that the interface between the relay node and the access network device needs to be removed, fourth removal indication information is sent to the relay node, and / or first removal indication information is sent to the access network device, the fourth removal indication information is used to instruct the relay node to remove the interface between it and the access network device, and the first removal indication information is used to instruct the access network device to remove the interface between it and the relay node.

16. The method according to claim 14 or 15, characterized in that The method further comprises: A second message is received from the relay node or a source host node of the relay node, where the second message includes identification information of the access network device.

17. The method according to claim 16, characterized in that The second message comes from the source host node, and the second message is a handover request message or a UE context retrieval response message. The handover request message is used to request that the mobile terminal MT of the relay node be switched to the target host node, and the UE context retrieval response message carries the context of the MT; or, the second message comes from the relay node, and the second message is a radio resource control RRC message or an Xn interface application protocol XnAP message.

18. A communication method, characterized in that: The method is applied to a relay node, and includes: receiving maintenance instruction information from a target host node of the relay node, wherein the maintenance instruction information is used to instruct the relay node to maintain an interface between the relay node and an access network device; Sending configuration update information to the access network device, where the configuration update information includes the Internet Protocol (IP) address of the relay node under the target host node.

19. The method according to claim 18, characterized in that The maintenance instruction information includes identification information of the access network device or the IP address of the access network device.

20. The method according to claim 18 or 19, characterized in that The method further comprises: A second message is sent to the source host node of the relay node or the target host node, where the second message includes identification information of the access network device.

21. A communication method, characterized in that: The method is applied to a relay node, and includes: receiving fourth removal instruction information from a target host node of the relay node, where the fourth removal instruction information is used to instruct the relay node to remove an interface between the relay node and the access network device; In response to the fourth removal indication information, a process of removing the interface between the access network device and the access network device is initiated.

22. The method according to claim 21, characterized in that The fourth removal indication information includes identification information of the access network device or an Internet Protocol IP address of the access network device.

23. The method according to claim 21 or 22, characterized in that The method further comprises: A second message is sent to the source host node of the relay node or the target host node, where the second message includes identification information of the access network device.

24. A communication method, characterized in that: The method is applied to an access network device, and the method includes: Receiving first removal instruction information from a target host node of the relay node, where the first removal instruction information is used to instruct the access network device to remove an interface between the access network device and the relay node; In response to the first removal indication information, a process of removing the interface with the relay node is initiated.

25. The method according to claim 24, characterized in that The first removal instruction information includes identification information of the relay node or the Internet IP address of the relay node under the source host node.

26. A communication device, characterized in that: The method comprises modules or units for implementing the method according to any one of claims 1 to 25.

27. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, wherein the computer program includes program instructions. When the program instructions are executed, the computer is caused to perform the method according to any one of claims 1 to 25.

28. A communication device, characterized in that: The communication device comprises a processor coupled to a memory, wherein the memory is used to store programs or instructions. When the programs or instructions are executed by the processor, the communication device performs the method according to any one of claims 1 to 25.

29. A chip, characterized in that: include: A communication interface, used for sending and receiving signals from the chip; A processor, configured to execute computer program instructions so that a communication device comprising the chip performs the method according to any one of claims 1 to 25.

30. A computer program product, characterized in that The computer program product comprises a computer program, wherein the computer program comprises program instructions, and when the program instructions are executed, the computer is caused to perform the method according to any one of claims 1 to 25.

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