Node in a communication network and method thereof

Abstract

The application provides a node in a communication system and a method thereof, the method comprising: receiving, by a first node, a first message from a fourth node, the first message comprising information configuring the first node to migrate; and performing, by the first node, data transmission according to the received first message.

Description

Technical Field

[0001] The present application relates to wireless communication technology, and in particular to a device and method for exchanging user-related contexts between a centralized unit and distributed units of a base station. Background Art

[0002] In the NR New Radio Access (NR) network, in order to expand the network coverage, a relay network architecture, namely IAB (Integrated Access and Backhaul), is proposed.

[0003] To facilitate user data transmission in multi-hop relay networks, 3GPP has defined a new protocol layer, the Backhaul Adaptation Protocol (BAP). This protocol layer is configured within the distribution unit of an anchor node and relay nodes (e.g., the mobile terminal portion of a relay node and / or the distribution unit portion of a relay node), above the Radio Link Control (RLC) layer. Its primary function is to route and map data packets. To transmit user data between a relay node and an anchor node, the backhaul link and the F1 interface between the distribution unit of the relay node and the anchor node must be configured. This configuration includes, but is not limited to, the BAP address, routing configuration (e.g., routing identifier information, which indicates different transmission routes and includes the BAP address and path identifier of the destination receiving node), backhaul link channel configuration, tunnel configuration, and tunnel-specific backhaul link configuration.

[0004] The above information is provided as background information only to assist with an understanding of the present invention. No determination has been made, and no assertion is made, as to whether any of the above may be applicable as prior art with respect to the present invention. Summary of the Invention

[0005] Technical issues

[0006] Current research assumes that when a relay node's parent node changes, the relay node must migrate. This process not only involves switching the mobile terminal portion of the relay node, but also the migration of users served by the relay node's distribution unit. This process involves a large amount of signaling interaction (signaling storm) within a short period of time, and user data can only be transmitted after these signaling interactions are completed. This process results in excessive signaling overhead, user data transmission interruptions, and significant latency.

[0007] Solution

[0008] The solution of traditional technology is: during the migration of relay nodes, the signaling overhead is large, and user data transmission is interrupted or delayed.

[0009] According to one aspect of the present invention, a method performed by a first node in a communication system is provided, comprising: receiving a first message from a fourth node, the first message including information for configuring the first node to migrate; and performing data transmission according to the received first message.

[0010] According to another aspect of the present invention, a method performed by a fourth node in a communication system is provided, comprising: obtaining information for configuring a first node for migration; and sending a first message to the first node, wherein the first message includes information for configuring the first node for migration.

[0011] In the method according to the embodiment of the present invention, the first message may include at least one of the following information: information related to a backhaul link, information related to an address, and information related to configuration retention.

[0012] In the method according to the embodiment of the present invention, the information related to the backhaul link may include at least one of the following information: address information used when serving the backhaul link and configuration information of a default backhaul link.

[0013] In the method according to an embodiment of the present invention, the configuration information of the default return link may include at least one of the following information: default routing identification information used for transmitting uplink data, identification information of the default return link channel used for transmitting data, identification information of the default return link channel used for transmitting uplink data, identification information of the default return link channel used for receiving downlink data, and indication information of the type of transmitted data.

[0014] In the method according to an embodiment of the present invention, the address-related information may include at least one of the following information: address index information, Internet IP address information, IP address usage information, and address information of a distribution unit of an anchor node corresponding to the IP address.

[0015] In the method according to an embodiment of the present invention, the information related to the configuration maintenance may include at least one of the following information: indication information for maintaining the configuration, indication information for maintaining the return link channel, indication information for maintaining the configuration of the mobile terminal part of the first node, indication information for maintaining the configuration of the distribution unit part of the first node, information on the configuration that the first node needs to maintain, information related to the type of data to be maintained, indication information for maintaining the source path, and information on the length of time to maintain the configuration.

[0016] In the method according to an embodiment of the present invention, the configuration information that the first node needs to maintain may include at least one of the following information: BAP configuration, BAP address, default route identification information, default return link channel identification information, return link channel identification information, tunnel configuration information, transport layer association configuration information, address configuration information, transmission route configuration, and indication information for maintaining one or more of the above configurations.

[0017] In the method according to an embodiment of the present invention, the information about the type of retained data may include at least one of the following information: all data, control plane data of the F1 interface, user plane data of the F1 interface, data of non-F1 interface, control plane data of the F1 interface associated with the user, control plane data of the F1 interface associated with the non-user, control data of the BAP layer, uplink data, downlink data and retained indication information.

[0018] The method of the fourth node according to an embodiment of the present invention may further include: sending a third message to the fifth node, where the third message may include at least one of the following information: identification information of the first node and address-related information.

[0019] In the method according to an embodiment of the present invention, the address-related information may include at least one of the following information: address index information, address information, address information for control plane data F1-C traffic of the F1 interface, address information for user plane data F1-U traffic of the F1 interface, address information for non-F1 traffic of data of a non-F1 interface, and indication information of the purpose of the address.

[0020] According to another aspect of the present invention, a method performed by a second node in a communication system is provided, comprising: sending a second message to a third node, the second message including information requesting configuration of migration of the first node; and receiving a second response message from the third node, the second response message including information for configuring migration of the first node.

[0021] According to another aspect of the present invention, a method performed by a third node in a communication system is provided, comprising: receiving a second message from a second node, the second message including information requesting configuration of migration of the first node; and sending a second response message to the second node, the second response message including information for configuring migration of the first node.

[0022] In the method according to an embodiment of the present invention, the second message may include at least one of the following information: configuration information of the first node, request information related to the address of the first node, information related to the return link of the first node, indication information requesting to maintain the configuration, and information related to the load of the first node.

[0023] In the method according to the embodiment of the present invention, the request information related to the address of the first node may include at least one of the following information: address request information, indication information of the address request, and address information used on the source path.

[0024] In the method according to the embodiment of the present invention, the information related to the backhaul link of the first node may include at least one of the following information: information related to the backhaul link channel and indication information of a request to maintain all backhaul link channels.

[0025] In the method according to an embodiment of the present invention, the indication information requesting to maintain the configuration may include at least one of the following information: indication information requesting to retain the configuration on the source path, indication information requesting to maintain the return link channel, indication information requesting to maintain the configuration of the mobile terminal part of the first node, indication information requesting to maintain the configuration of the distribution unit part of the first node, and indication information requesting to maintain the configuration.

[0026] In the method according to an embodiment of the present invention, the information related to the load of the first node may include at least one of the following information: information on the number of users accessing the first node, information on the number of bearers served by the first node, information related to the return link channel configured by the mobile terminal part of the first node, indication information of the hardware load, indication information of the transmission network layer capacity, and information on the cell load of the first node.

[0027] In the method according to an embodiment of the present invention, the second response message may include at least one of the following information: feedback information related to the address of the first node, response information for maintaining the configuration, configuration information related to the return link of the first node, information related to initiating user context migration, and indication information for accepting user migration.

[0028] In the method according to the embodiment of the present invention, the feedback information related to the address of the first node may include at least one of the following information: information of the address configured by the first node and setting value information of the IP packet.

[0029] In the method according to the embodiment of the present invention, the response information for retaining the configuration may include at least one of the following information: indication information of approving the request and the retained configuration information.

[0030] In the method according to an embodiment of the present invention, the information related to initiating user context migration may include at least one of the following information: indication information for initiating user context migration, identification information of the relay node to which the user accesses, information on the number of users allowed to be admitted, information on the number of wireless bearers allowed to be admitted, and clock information for initiating migration.

[0031] In the method according to the embodiment of the present invention, the indication information for accepting user migration may include at least one of the following information: indication information for stopping user context migration, information on the number of users that can still be accepted, and reason information.

[0032] According to another aspect of the present invention, a method performed by a second node in a communication system is provided, comprising: sending a fourth message to a third node, wherein the fourth message includes user configuration information; and receiving a fourth response message from the third node.

[0033] According to another aspect of the present invention, a method performed by a third node in a communication system is provided, comprising: receiving a fourth message from a second node, wherein the fourth message includes user configuration information; and sending a fourth response message to the second node.

[0034] In the method according to the embodiment of the present invention, the fourth message may include at least one of the following information: first information related to user configuration, information indicating the purpose of the message, and information related to migration.

[0035] In the method according to the embodiment of the present invention, the first information related to the configuration of the user may include at least one of the following information: first identification information of a cell and first configuration information related to user data.

[0036] In the method according to the embodiment of the present invention, the indication information of the message usage may include at least one of the following information: indication information of user context migration, indication information of non-switching, indication information of ignoring information, and reason information.

[0037] In the method according to the embodiment of the present invention, the information related to migration may include at least one of the following information: indication information of the end of migration and indication information of the number of users that have not yet migrated.

[0038] In the method according to the embodiment of the present invention, the fourth response message may include at least one of the following information: second information related to user configuration, indication information of user migration, and indication information of ignoring information.

[0039] In the method according to the embodiment of the present invention, the second information related to the user configuration may include at least one of the following information: second identification information of the cell and indication information of retaining configuration information of the user radio bearer.

[0040] In the method according to the embodiment of the present invention, the user migration indication information may include at least one of the following information: indication information for stopping user context migration, information on the number of users that can still be accommodated, and reason information.

[0041] The method of the third node according to the embodiments of the present application can further comprise: sending a fifth message to the second node, wherein the fifth message can comprise at least one of the following information: indication information of starting user context migration, identification information of the relay node accessed by the user, number information of users allowed to be admitted, number information of radio bearers of the users allowed to be admitted, clock information of starting migration, and indication information of user migration.

[0042] In the method according to the embodiments of the present application, the indication information of user migration can comprise at least one of the following information: indication information of stopping user context migration, number information of users that can still be admitted, and cause information.

[0043] The method of the second node according to the embodiments of the present application can further comprise: sending a sixth message to the third node, wherein the sixth message can comprise at least one of the following information: indication information of ending user context migration, and second configuration information related to user data.

[0044] In the method according to the embodiments of the present application, the second configuration information related to user data can comprise at least one of the following information: identification information of a radio bearer, transmission state information of uplink data, and transmission state information of downlink data.

[0045] The method of the third node according to the embodiments of the present application can further comprise: sending a seventh message to the second node, wherein the seventh message can comprise at least one of the following information: identification information of the relay node, indication information of releasing user context, indication information of releasing context of the relay node, and indication information of releasing configuration of the source path.

[0046] The method of the second node or the third node according to the embodiments of the present application can further comprise: sending an eighth message to the first node, wherein the eighth message comprises at least one of the following information: identification information of the relay node, indication information of releasing user context, indication information of releasing context of the relay node, and indication information of releasing configuration of the source path.

[0047] According to still another aspect of the present application, there are also provided nodes for performing one of the above-mentioned methods, including an anchor node, a distribution unit of the anchor node, a relay node, and the like. BRIEF DESCRIPTION OF DRAWINGS

[0048] The above and other aspects, features, and advantages of certain embodiments of the present application will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0049] Figure 1 Schematic architecture of a multi-hop relay network (IAB network).

[0050] Figure 2Several examples of relay node migration scenarios according to embodiments of the present invention are shown.

[0051] Figure 3 The flowchart shows a process of data transmission performed by a first node according to an embodiment of the present invention.

[0052] Figure 4 (a) shows an example in which a first node transmits data with a second node or a third node on a target path according to an embodiment of the present invention.

[0053] Figure 4 (b) shows an example in which the first node performs data transmission with the second node on the source path according to an embodiment of the present invention.

[0054] Figure 4 (c) shows an example in which the first node transmits data with the second node or the third node on the source path and the target path according to an embodiment of the present invention.

[0055] Figure 5 An example of a migration process of a first node according to an embodiment of the present invention is shown.

[0056] Figure 6 An example of notifying the distribution unit of the anchor node on the target path of the address of the first node according to an embodiment of the present invention is shown.

[0057] Figure 7 An example of a method for user context migration according to an embodiment of the present invention is shown.

[0058] Figure 8 The embodiment of the present invention is shown in Figure 7 An example of a process flow may also be included before step 2-1.

[0059] Figure 9 The embodiment of the present invention is shown in Figure 7 An example of a process that may also be included after step 2-2.

[0060] Figure 10 An example of a process that may be included after completing the migration of the user context according to an embodiment of the present invention is shown.

[0061] Figure 11 is a block diagram of an anchor node according to an embodiment of the present invention.

[0062] Figure 12 is a block diagram of a relay node according to an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The following description, with reference to the accompanying drawings, is provided to facilitate a comprehensive understanding of the various embodiments of the present invention as defined by the claims and their equivalents. It includes various specific details to assist in such understanding, but these details are to be regarded as merely illustrative. Therefore, those skilled in the art will recognize that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present invention. Furthermore, descriptions of well-known functions and configurations may be omitted for clarity and conciseness.

[0064] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the invention. Therefore, it should be understood by those skilled in the art that the following description of various embodiments of the invention is provided for illustration purposes only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0065] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0066] In addition, the detailed description of the embodiments of the present invention is mainly based on a wireless communication system of a multi-hop relay network, but without departing from the scope of the present invention, the subject matter of the present invention can be applied to other communication systems with similar technical backgrounds and channel forms after slight modifications, and can be determined by those skilled in the art.

[0067] The advantages and features of the present invention and the manner in which they are achieved will become apparent by reference to the various embodiments described in detail below in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments set forth below, but may be implemented in a variety of different forms. The following embodiments are provided only to fully disclose the present invention and to inform those skilled in the art of the scope of the present invention, and the present invention is limited only by the scope of the appended claims. Throughout the specification, the same or similar reference numerals designate the same or similar elements.

[0068] Here, it will be understood that each step in the flowchart illustration, as well as the combination of steps in the flowchart illustration, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing device create a means for implementing the functions specified in the flowchart. These computer program instructions can also be stored in a computer-usable or computer-readable memory, which can instruct the computer or other programmable data processing device to operate in a specific manner, such that the instructions stored in the computer-usable or computer-readable memory produce an article of manufacture including instruction means for implementing the functions specified in the flowchart. The computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operations performed on the computer or other programmable device produce a computer-implemented process, such that the instructions executed on the computer or other programmable device provide operations for implementing the functions specified in the flowchart.

[0069] And each block in the flowchart description can represent a module, segment or portion of code, which includes one or more executable instructions for implementing the specified (multiple) logical functions. It should also be noted that in some alternative implementations, the functions or steps marked in the flowchart may not occur in sequence. For example, depending on the functions involved, two steps shown in succession can actually be performed substantially simultaneously, or sometimes the steps can be performed in reverse order. In some cases, multitasking and parallel execution may be advantageous.

[0070] As used herein, "unit" or "module" refers to a software element or hardware element that performs a predetermined function, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). However, a "unit" or "module" is not always limited to the meaning of software or hardware. A "unit" or "module" can be constructed to be stored in an addressable storage medium or to execute one or more processors. Therefore, a "unit" or "module" for example includes a software element, an object-oriented software element, a class element or a task element, processing, a function, an attribute, a process, a subroutine, a segment of program code, a driver, firmware, microcode, a circuit, data, a database, a data structure, a table, an array and a parameter. The elements and functions provided by a "unit" or "module" can be combined into a smaller number of element "units" or "modules", or divided into a larger number of element "units" or "modules". In addition, an element "unit" or "module" can be implemented to reproduce one or more central processing units (CPUs) in a device or a secure multimedia card.

[0071] Aspects of the application, as generally described herein, and in the drawings, can be arranged, substituted, combined, separated, and designed in various different configurations, all of which are contemplated herein. Additionally, the features illustrated in each drawing can be used in combination with features illustrated in other drawings. Thus, the drawings are not to be considered as limiting the scope of the application as described herein. Figure 1 Generally, it is contemplated that the functions of the various embodiments can be implemented, at least in part, by software stored in and executed by one or more general purpose or special purpose programmable microprocessors, microcontrollers, digital signal processors or other components. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. As used herein, "software" is intended to encompass a non-transitory computer-readable medium having instructions, e.g., executable instructions, stored thereon. Also, it is contemplated that software can be downloaded into the memory of the microprocessor from another computer via a computer network, e.g., the Internet, a local area network, a wide area network, a wireless network, a modem, etc.

[0072] It will be understood that, although the terms "first", "second", etc. can be used herein to describe various elements, components, and / or parts, these elements, components, and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, and / or part from another element, component, and / or part. Thus, a first element, component, and / or part discussed below could be termed a second element, component, and / or part without departing from the teachings of the present application.

[0073] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. It will be understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0074] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0075] a. Constituent of the Invention

[0076] The present invention comprises two aspects:

[0077] ■Migration of the Relay Node

[0078] ■Migration of the User Configuration Information (or Context Information)

[0079] b. Embodiments of the Invention

[0080] The message names in the present invention are only examples, and other message names can also be used.

[0081] The "first", "second", etc. contained in the message names of the present invention are only examples of the messages, and do not represent the execution order.

[0082] Detailed descriptions of steps not related to the present invention are omitted.

[0083] In the present invention, the mobile terminal function of the relay node is equivalent to the mobile terminal part of the relay node, and the distribution unit function of the relay node is equivalent to the distribution unit part of the relay node.

[0084] In the present invention, The type of data transmitted by the relay node on the backhaul link Including: control plane data of F1 interface (F1AP message, or F1-C Traffic), control plane data of F1 interface associated with users (UE-associated F1AP message, or UE-associated F1-C traffic), control plane data of F1 interface non-user associated (non-UE-associated F1AP message, or non-UE-associated F1-C traffic), user plane data of F1 interface (F1-Utraffic), data of non-F1 interface (non-F1 traffic), control data of BAP layer (BAP Control Protocol Data Unit (BAP Control Protocol Data Unit), such as data related to flow control of BAP layer, data related to radio link failure of BAP layer, etc.), non-user plane data (non-UP traffic, such as F1-C traffic, non-F1 traffic, BAPControl PDU, etc.).

[0085] The nodes involved in the present invention are as follows:

[0086] ■First node: relay node, or the distribution unit function of relay node, or the mobile terminal function of relay node

[0087] ■ Second node: source node, which can be a base station, a centralized unit of a base station, or the control plane portion of a centralized unit of a base station, or the user plane portion of a centralized unit of a base station, or an anchor node, or a centralized unit of an anchor node, or the control plane portion of a centralized unit of an anchor node, or the user plane portion of a centralized unit of an anchor node

[0088] ■ Third node: target node, which can be a base station, a centralized unit of a base station, or the control plane part of a centralized unit of a base station, or the user plane part of a centralized unit of a base station, or an anchor node, or a centralized unit of an anchor node, or the control plane part of a centralized unit of an anchor node, or the user plane part of a centralized unit of an anchor node

[0089] The second node and the third node may be the same node or different nodes.

[0090] ■ Fourth node: a node to which the relay node is connected, such as a base station, a centralized unit of a base station, or a control plane portion of a centralized unit of a base station, or a user plane portion of a centralized unit of a base station, or an anchor node, or a centralized unit of an anchor node, or a control plane portion of a centralized unit of an anchor node, or a user plane portion of a centralized unit of an anchor node. In one embodiment, the node may be the second node described above, and in another embodiment, the node may be the third node described above.

[0091] ■Fifth node: the distribution unit of the base station or the distribution unit of the anchor node

[0092] The present invention considers relay node migration, which can also be considered relay node switching. During the migration process, the parent node (parent node) to which the relay node is connected changes. This parent node can be another relay node or a distribution unit of an anchor node.

[0093] The purpose of the present invention is to enable the relay node to maintain the configuration on the source path during migration, or to configure a return link channel on the target path to maintain the continuity of user data transmission through signaling interaction between the source anchor node, the target anchor node and the relay node.

[0094] By migrating user context between the source anchor node and the target anchor node, signaling storms can be avoided and signaling overhead during user migration can be reduced.

[0095] Figure 1A schematic architecture of a multi-hop relay network (IAB network) is provided. The figure shows a network architecture including an anchor node (e.g., an IAB donor / anchor) and two relay nodes (e.g., an IAB node, an IAB node). Users in the multi-hop network can access the network through the anchor node, the anchor node's distribution unit, or the relay node. For example, users 1 / 2 / 3 access the relay network through the anchor node's distribution unit, the distribution unit portion of relay node 1, and the distribution unit portion of relay node 2, respectively. The anchor node can be an independent base station or a base station composed of a centralized unit CU (in one embodiment, it can be an IAB anchor node's centralized unit, an IAB-donor central unit) and a distribution unit DU (in one embodiment, it can be an IAB anchor node's distributed unit, an IAB-donor distributed unit). A relay node includes a mobile terminal function and a distributed unit function (in another example, the relay node can also be described as including a mobile terminal portion and a distributed unit portion). The mobile terminal function is used to communicate with the relay node's upper-level node (e.g., the mobile terminal portion of relay node 1 is used to communicate with the anchor node or the anchor node's distributed unit, and the mobile terminal portion of relay node 2 is used to communicate with the distributed unit portion of relay node 1), and the distributed unit portion is used to communicate with the relay node's lower-level node (e.g., the distributed unit portion of relay node 1 is used to communicate with user 2, and can also be used to communicate with the mobile terminal portion of relay node 2). The mobile terminal portion of the relay node can be regarded as a user accessing the network, and therefore has the functions of an ordinary user (non-relay node) (e.g., the mobile terminal portion can establish a signaling radio bearer (SRB) with its upper-level node to send radio resource control (RRC) messages, and can also establish a data radio bearer (DRB) to send data). The centralized unit of the anchor node includes the following protocol stacks: the protocol stack of the service control plane, including the radio resource control (RRC) protocol layer and the packet data convergence protocol (PDCP) layer; the protocol stack of the service user plane, including the service data adaptation protocol (SDAP) layer and the PDCP layer.The distributed unit of an anchor node or a relay node includes the following protocol stacks: the service control plane and the user plane protocol stacks, including the Radio Link Control (RLC) protocol layer, the Medium Access Control (MAC) protocol layer, and the Physical Layer (PHY). The interface between the centralized unit of an anchor node and the distributed unit of an anchor node, and between the centralized unit of an anchor node and the distributed unit of a relay node, is the F1 interface (see 3GPP TS 38.473).

[0096] In a relay network, the link between a relay node and an anchor node or a distribution unit of an anchor node, or between relay nodes, is a backhaul link. One or more different backhaul link channels are established on the backhaul link, such as Figure 1 In the backhaul link channel 1 and backhaul link channel 2, backhaul link channel 1 is located between the anchor node and relay node 1, and backhaul link channel 2 is located between relay node 1 and relay node 2. An example of a backhaul link channel is a backhaul link radio link control (RLC) protocol layer channel, i.e., a backhaul link RLC Protocol Layer Channel. In a relay network, each backhaul link channel is used to send data packets belonging to the same user or different users. The data packets can be data radio bearer (DRB) data packets, signaling radio bearer (SRB) data packets, control plane data packets on the F1 interface, user plane data packets on the F1 interface, or data packets on non-F1 interfaces (such as Internet Protocol Security (IPSec) data packets, Stream Control Transmission Protocol (SCTP) data packets, Operation Administration and Maintenance (OAM) data packets, etc.).

[0097] Figure 2 Several examples of relay node migration scenarios according to embodiments of the present invention are shown:

[0098] 1) Intra-CU / intra-DU (same anchor node centralized unit and same anchor node distributed unit): During the migration process, the centralized unit and distributed unit of the anchor node serving the relay node remain unchanged.

[0099] 2) Intra-CU / inter-DU (same anchor node centralized unit and different anchor node distributed unit): During the migration process, the centralized unit of the anchor node serving the relay node does not change, but the distributed unit of the anchor node does change.

[0100] 3) Inter-CU / inter-DU (different anchor node centralized units and different anchor node distributed units): During the migration process, the centralized unit and distributed unit of the anchor node serving the relay node are changed.

[0101] In the present invention, the path connected (used) by the relay node before migration is the source path, and the path connected (used) after migration is the target path.

[0102] The key information involved in this invention is as follows:

[0103] User configuration information (or user context information) The user is a user accessing the network. In one embodiment, the user is any user accessing the network. In one embodiment, the user is a user accessing the network through a relay node. In one embodiment, the user is a user who maintains a connection with the relay node during the migration of the relay node. In one embodiment, the user may be a relay node or a mobile terminal portion of a relay node. The content of this information can be found in the HANDOVER REQUEST and HANDOVER REQUEST ACKNOWLEDGE messages in TS38.423 / TS36.423. In addition, it may also include at least one of the following information:

[0104] ■ User identification information on the F1 interface (e.g., gNB-CU UE F1AP ID, gNB-DU UE F1AP ID). This information can be used by the distributed unit of the relay node to which the user is connected and the centralized unit of the anchor node when configuring the user. In one embodiment, the centralized unit of the anchor node can be the centralized unit to which the relay node was connected before migration.

[0105] Configuration information of user radio bearers (e.g., DRBs). This configuration information may include the configuration of one or more radio bearers. For a radio bearer, this information includes at least one of the following:

[0106] ■ Information related to the quality of service (QoS) satisfied by the relay node. This information is used to indicate the QoS of the radio bearer that the relay node has satisfied when serving the radio bearer. In one embodiment, the relay node is the relay node accessed by the user. Furthermore, the relay node may have migrated, and after the migration, the user still accesses the network through the relay node. This information includes at least one of the following: non-dynamic 5QI descriptor, dynamic 5QI descriptor, allocation and retention priority, GBR QoS flow information, etc. For specific information, please refer to 3GPP TS38.473.

[0107] It should be noted that the aforementioned "information related to QoS satisfied by the relay node" is different from the QoS-related information for each radio bearer in conventional technologies (referred to as "radio bearer QoS information" in this disclosure, and the parameters contained in this information can be found in 3GPP TS38.473). The "radio bearer QoS information" indicates the QoS requirements of the radio bearer. Nodes receiving this information need to configure resources to serve the radio bearer according to the content contained in this information to meet the QoS requirements of the radio bearer. The aforementioned "information related to QoS satisfied by the relay node" indicates the QoS requirements already satisfied by the relay node. Nodes receiving this information determine the QoS requirements that still need to be met (referred to as the remaining QoS requirements in this disclosure) based on this information, and thus configure resources to serve the radio bearer to meet the "remaining QoS requirements." A beneficial effect of this information is that the node receiving this information can understand the QoS that the relay node can meet when serving the user's radio bearer and determine how to configure other nodes to serve the user's radio bearer, thereby enabling the relay node and other nodes to jointly serve the user's radio bearer and meet the QoS requirements of the radio bearer. Another beneficial effect of this information is that the node receiving the information can try to configure the relay node to serve the user's radio bearer according to the QoS indicated by the information, thereby eliminating the need to modify the configuration information of the relay node when serving the user's radio bearer.

[0108] ■ Information about the tunnel of uplink data. The uplink data is the data sent by the relay node to the anchor node. The tunnel may be one or more. The information indicates the information of the anchor node or the centralized unit of the anchor node or the user plane part of the centralized unit of the anchor node. When the relay node migrates, the tunnel may be the uplink tunnel used before the migration or the uplink tunnel used after the migration. The information may include only the uplink tunnel used before the migration or only the uplink tunnel used after the migration, or both the uplink tunnel used before the migration and the uplink tunnel used after the migration. For one tunnel, the information includes the following:

[0109] At least one of the following information:

[0110] ◆Tunnel identification information

[0111] IP address

[0112] ◆TEID

[0113] ◆Route identification information, which is used to indicate the transmission path of the above-mentioned uplink data (further, the uplink data is sent through the above-mentioned tunnel), which includes the address information of the receiving node (such as, BAP address) and / or transmission path identification information (such as, path ID). Further, based on this information, the relay node can add this information to the uplink data packet sent through the above-mentioned tunnel

[0114] ◆The identification information of the next hop node. The next hop node is the node that directly receives the uplink data when the relay node sends the uplink data (furthermore, the uplink data is sent through the above tunnel). In other words, the relay node sends the uplink data to the next hop node, which then sends the uplink data directly or indirectly (through other nodes) to the destination node of the uplink data. Based on this information, the relay node knows which node to send the uplink data to.

[0115] ◆ Identification information of the backhaul link channel. The backhaul link channel is the backhaul link channel used by the relay node to send the uplink data (furthermore, the uplink data is sent through the above tunnel) to the above next-hop node. Based on this information, the relay node knows which backhaul link channel to use to send the uplink data.

[0116] One beneficial effect of including this information is that the receiving node can update the configuration of the uplink tunnel of the user data based on the information, and obtain the configuration of the uplink data transmission, such as the transmission path of the uplink data packet, the information to be added in the uplink data packet, the next hop node for receiving the uplink data packet, and the return link channel used to transmit the uplink data packet; another beneficial effect of including this information is that the receiving node can obtain the configuration information of the uplink tunnel of the wireless bearer served by the relay node, thereby helping the receiving node to update the configuration information of the uplink tunnel; another beneficial effect of including this information is that the receiving node can configure the uplink tunnel of the wireless bearer served by the relay node based on the received information.

[0117] ■ Information about the tunnels of downlink data. This downlink data is data sent by the anchor node to the relay node. This tunnel may be one or more. This information indicates information about the relay node or the distribution unit portion of the relay node. When a relay node migrates, the tunnel may be the downlink tunnel used before the migration or the downlink tunnel used after the migration. This information may include only the downlink tunnels used before the migration, only the downlink tunnels used after the migration, or both the downlink tunnels used before the migration and the downlink tunnels used after the migration. For each tunnel, this information includes at least one of the following:

[0118] ◆Tunnel identification information

[0119] IP address

[0120] ◆TEID

[0121] The configuration value information of the Differentiated Services Code Point (DSCP) field in the downlink data packet (furthermore, the downlink data packet is sent through the above tunnel)

[0122] The configuration value information of the flow label field in the downlink data packet (furthermore, the downlink data packet is sent through the above tunnel)

[0123] One benefit of including the information is that the receiving node can update the configuration of the downlink tunnel of the user data according to the information, and learn the configuration of the downlink data transmission, such as the configuration value of the DSCP field and the configuration value of the flow label field included in the downlink data packet. Another benefit of including the information is that the receiving node can learn how to send the downlink data to the relay node, such as the address of receiving the downlink data and the information required to be included in the downlink data packet, such as the configuration value of the DSCP field and the configuration value of the flow label field. Another benefit of including the information is that the receiving node can configure the downlink tunnel of the wireless bearer served by the relay node according to the received information.

[0124] The first aspect of the present application

[0125] The first node (relay node) migrates, which can be Figure 2 In order for the first node to transmit data on the target path, it is necessary to configure the tunnel (such as the tunnel used for transmitting DRB) or transmission layer association (such as the transmission layer association used for transmitting F1-C traffic) used for transmitting data between the first node (or the distributed unit part of the first node) and the second node or the third node, and further, it is necessary to configure the backhaul link information (such as BH Information, which can include BAP routing ID, identification of backhaul link channel, identification or address information of next hop node, such as BAP address) used for transmitting data on the above-mentioned tunnel or transmission layer association. However, it takes time to complete these configurations, and before the configuration of the tunnel and / or transmission layer association and / or backhaul link is completed, the first node cannot transmit data on the tunnel or transmission layer association with the second node or the third node. Therefore, in order to avoid interruption of data transmission or reduce the delay of data transmission, the method considered by the present application is:

[0126] ■During or after migration, the first node maintains the configuration on the source path, so as to transmit data using the source path

[0127] ■After the mobile terminal part of the first node switches to the target path (such as after completing the random access process), the first node transmits data with the second node or the third node using the target path

[0128] To implement the above-mentioned method, Figure 3 An example of a flow of data transmission by the first node according to an embodiment of the present application is shown in FIG. 1, which comprises the following steps: Figure 3 As shown, the flow of the present application comprises the following steps:

[0129] Step 1-1: The fourth node sends a first message to the first node, which can be a first configuration request message, and the first message includes information for configuring the first node to migrate, and the message is used to configure the first node to migrate. In an embodiment, when the first node migrates, the message indicates the configuration information required by the first node during and / or after migration (or the configuration information required by the first node after configuration update), and the fourth node can be a node connected to the first node before migration (such as the second node described above) or a node connected to the first node after migration (such as the third node described above). It should be noted that the migration before (or the configuration update before) mentioned above or below can refer to before the first node receives the first message. One or more information in the message can be determined by the fourth node and then sent to the first node by the fourth node through the message, or determined by the second node and sent to the first node through the message, or determined by the third node and sent to the first node through the message, or determined by the third node and then sent to the second node, and finally sent to the first node by the second node. The message includes at least one of the following information:

[0130] ■Information related to the backhaul link, which configures the backhaul link used by the first node, and the information includes at least one of the following information:

[0131] ■Address information used when serving the backhaul link, such as BAP address information (BAP address), and in an embodiment, the address can be address information used by the first node after migration

[0132] ■Configuration information of the default return link, which indicates the information used before the first node obtains the configuration of the return link used to transmit various types of data (such as during the initial access of the relay node to the network, during the migration process, during the RRC recovery process, during the RRC reconstruction process, etc.). During the migration of the first node, the information may be the configuration information used after the first node accesses the target path, then the return link configured in the configuration information (such as the return link channel, routing identifier, etc.) is the return link used by the first node on the target path. In one embodiment, the configuration information of the default return link may not distinguish between data types, so that the transmission of all types of data uses the same set of configurations. In another embodiment, the configuration information of the default return link may distinguish between different types of data, so that the information includes a set of configurations for the transmission of each type of data. Regardless of which implementation method is adopted, for a set of configurations, the information includes at least one of the following information:

[0133] ◆Default routing information used to transmit uplink data

[0134] ◆The identification information of the default return link channel used to transmit data, which can include both downlink data and uplink data

[0135] ◆Identification information of the default return link channel used to transmit uplink data

[0136] ◆Identification information of the default return link channel used to receive downlink data

[0137] ◆Indication of the type of data being transmitted, the type of data indicated by this information may be the above-mentioned “ Relay Section The type of data transmitted by the node on the backhaul link ", further, the indication information may be an explicit indication or an implicit indication (e.g., the name of the IE included in the message may be used as an indication of the data type).

[0138] Specifically, the above-mentioned "default backhaul link configuration information" may have the following possible implementations (the following implementations are only examples and other possible implementations are not excluded). In one implementation, a default configuration is given for the transmission of user plane data, and the information includes at least one of the following information:

[0139] ◆Default routing information used to transmit uplink user plane data

[0140] ◆The identification information of the default backhaul link channel used to transmit user plane data, which can include both downlink data and uplink data

[0141] ◆Identification information of the default backhaul link channel used to transmit uplink user plane data

[0142] ◆Identification information of the default return link channel used to receive downlink user plane data

[0143] In one embodiment, a default configuration is provided for the transmission of non-user plane data, and the information includes at least one of the following information:

[0144] ◆Default routing information used to transmit uplink non-user plane data

[0145] ◆Identification information of the default backhaul link channel used to transmit non-user plane data, which can include both downlink data and uplink data

[0146] ◆Identification information of the default backhaul link channel used to transmit uplink non-user plane data

[0147] ◆Identification information of the default return link channel used to receive downlink non-user plane data

[0148] In one embodiment, a default configuration is provided for the transmission of user plane data and non-user plane data, and the information includes at least one of the following information:

[0149] ◆The default routing identifier information used to transmit uplink data. This configuration indicates that uplink user plane data and non-user plane data use the same default routing identifier information

[0150] ◆The identification information of the default backhaul link channel used to transmit user plane data, which can include both downlink data and uplink data

[0151] ◆Identification information of the default backhaul link channel used to transmit non-user plane data, which can include both downlink data and uplink data

[0152] ◆Identification information of the default backhaul link channel used to transmit uplink user plane data

[0153] ◆Identification information of the default backhaul link channel used to transmit uplink non-user plane data

[0154] ◆Identification information of the default return link channel used to receive downlink user plane data

[0155] ◆Identification information of the default return link channel used to receive downlink non-user plane data

[0156] Furthermore, the "default backhaul link configuration information" may be provided separately for different nodes that perform data transmission with the first node. For example, the "default backhaul link configuration information" may include configuration information used when the first node performs data transmission with the second node, and may also include configuration information used when the first node performs data transmission with the third node.

[0157] The beneficial effect of the above-mentioned "configuration information of the default backhaul link" is that, before the first node obtains the configuration of the backhaul link used for transmitting various types of data (such as the configuration of the backhaul link channel, the configuration of the IP address, the configuration of the tunnel, the information of the backhaul link (such as the backhaul link channel, the BAP routing identifier, the BAP address or identifier of the next hop node, etc.), etc.), the first node can transmit data (such as the data of the distributed unit part of the first node) on the target path according to the information, which can reduce the time delay of data transmission during the migration of the first node. In an embodiment, after the migration of the first node, the first node can use the configuration indicated by the above-mentioned "configuration information of the default backhaul link" to transmit data (such as the sending of uplink data, and / or the receiving of downlink data) on the target path, which can be the transmission between the first node and the third node; or it can be the transmission between the first node and the second node, and in the transmission process, the first node needs to send the data to the distributed unit of the anchor node on the target path, and then the data is sent to the second node by the distributed unit of the anchor node on the target path, or the data needs to be sent to the distributed unit of the anchor node on the target path by the second node, and then the data is sent to the first node by the distributed unit of the anchor node on the target path.

[0158] ■Information related to the address, which indicates the address related information used by the first node when communicating with the network side (such as the fourth node, and / or the second node, and / or the third node). In an embodiment, the address can be an IP address. The information contained in the information is the address used by the first node when communicating with the node connected after the migration (or after the configuration update) (such as the third node), which includes at least one of the following information:

[0159] ■Index information of the address

[0160] ■IP address information

[0161] ■Usage information of the IP address, which indicates the type of data transmitted by the above-mentioned IP address, such as the control plane data used for transmitting the F1 interface, the user plane data used for transmitting the F1 interface, the data used for transmitting the non-F1 interface, etc.

[0162] ■Address information of the distributed unit of the anchor node corresponding to the IP address, such as BAP address information

[0163] ■ Information about configuration maintenance, which indicates the configuration that the first node needs to maintain. In one embodiment, when the first node migrates, the information indicates the configuration information that the first node needs to maintain during or after the migration process, and the maintained configuration information is the configuration information used before the migration, and the maintained configuration is used for the first node to continue to maintain data transmission with the node connected before the migration (i.e., the node on the source path) during or after the migration process; in another embodiment, when the first node undergoes a configuration update, the information indicates the configuration information that the first node needs to continue to maintain after the configuration update, and the maintained configuration information is the configuration information used before the configuration update, and the maintained configuration is used for the first node to continue to maintain data transmission with the node connected before the configuration update after the configuration update. The information includes at least one of the following information:

[0164] ■Indication information for maintaining configuration, the function of this information is to instruct the first node to continue to maintain the configuration of the node connected to it before migration (or before configuration update), so that the first node can continue to serve the first node or the distribution unit part of the first node using the source path. The configuration that needs to be maintained includes the configuration of the mobile terminal part of the first node (such as BAP configuration, return link channel configuration, etc.) and the configuration of the distribution unit part (such as tunnel configuration, transport layer association configuration, return link information, address configuration, etc.). In one embodiment, the function of this configuration is to serve the distribution unit part of the first node on the source path. In one embodiment, the indication information instructs the first node to maintain the configuration required to transmit the data of its distribution unit part on the source path, such as Keep Source BAP Indication, Keep Source BH link Indication, etc. The indication information can be an explicit message or an implicit message. As an example, the indication information can be implicitly indicated through DAPS-config (TS38.331), but it should be noted that this method expands the role of DAPS-configIE in traditional technology and changes the behavior of the receiving node. In traditional technology, DAPS-config IE is given for a DRB, that is, the DRB request containing this IE configures the DRB as a DAPS bearer, and the transmission of the DRB data needs to be carried out according to the existing DAPS mechanism. However, in the present invention, if the configuration information of at least one DRB received by the first node contains the DAPS-config IE, the first node is implicitly notified to retain the required configuration of the distributed unit part serving the first node or the first node on the source path (such as BAP configuration, and / or backhaul link channel configuration, tunnel configuration, transport layer association configuration, backhaul link information, address configuration, etc.)

[0165] ■ Instruction information for maintaining the backhaul link channel, which is used to indicate that one or more backhaul link channels used on the source path need to be maintained. For each backhaul link channel, the instruction information includes identification information of the backhaul link channel. Further, after receiving the instruction information, the first node will continue to use the source path to transmit data transmitted by these backhaul link channels.

[0166] ■ Maintaining the configuration indication information of the mobile terminal part of the first node, which may include BAP configuration and / or backhaul link channel configuration, etc.

[0167] ■ Maintain the configuration information of the distribution unit part of the first node, which may include the configuration of the tunnel, the configuration of the transport layer association, the information of the backhaul link, the address configuration, etc.

[0168] ■ Information about the configuration that the first node needs to maintain. This information is used to notify the first node of the configuration that needs to be maintained. This information includes at least one of the following:

[0169] ◆BAP configuration, which includes at least one of the following information: 1) the BAP address of the first node, 2) the default routing identification information, 3) the identification information of the default return link channel

[0170] BAP address

[0171] ◆Default routing identification information

[0172] ◆Default backhaul link channel identification information

[0173] ◆ Identification information of the backhaul link channel. The first node will be configured with one or more backhaul link channels on the source path. This information provides the identification information of one or more backhaul link channels that need to be maintained. Furthermore, this information also implicitly indicates the configuration information of the data transmitted on the channel that needs to be maintained, such as the tunnel configuration, such as the transport layer association configuration, etc.

[0174] Tunnel configuration information, which indicates the configuration of the tunnel that needs to be maintained. The tunnel can be an uplink tunnel or a downlink tunnel. For a tunnel, the configuration information includes at least one of the following information:

[0175] Tunnel identification information

[0176] Tunnel information, such as the IP address and / or GTP-U TEID, where the IP address is the IP address of one end of the tunnel

[0177] Downlink tunnel information, such as an IP address and / or GTP-U TEID. The IP address may be an IP address on the first node side (such as an address on the distribution unit side of the first node).

[0178] Uplink tunnel information, such as IP address and / or GTP-U TEID. The IP address may be the address of the anchor node (or the centralized unit of the anchor node or the user plane portion of the centralized unit of the anchor node)

[0179] Transport layer association configuration information, which indicates the configuration of the transport layer association that needs to be maintained, and includes at least one of the following information:

[0180] Transport layer associated identification information

[0181] Transport layer association information, such as the IP address and / or port number of the transport layer association. The IP address is the IP address of one end of the transport layer association.

[0182] Downlink transport layer related information, such as IP address and / or port number. The IP address may be the IP address of the first node (such as the address of the distribution unit of the first node).

[0183] Uplink transport layer related information, such as IP address and / or port, where the IP address can be the address of the anchor node (or the centralized unit of the anchor node or the user plane part of the centralized unit of the anchor node)

[0184] ◆Address configuration information, which indicates the address that needs to be maintained. The address can be an IP address or a BAP address. In one embodiment, the information can be included in a new IE (such as the kept address (KeptAddress)); in one embodiment, the information can be included in an existing IE, such as the IAB-IP-AddressConfiguration-r16 IE (TS38.331) of the traditional technology; specifically, if the IAB-IP-AddressConfiguration-r16 IE is used to add a new IP address, further, indication information can be added to the IE, which indicates that the first node needs to maintain the address corresponding to the index information contained in the IE before the migration (or before the configuration is updated). If the IE is used to update the IP address, further, indication information can be added to the IE, which indicates that the first node needs to maintain the address before the update and use the new IP address.

[0185] ◆Transmission route configuration, which indicates the transmission route that needs to be maintained. There may be one or more transmission routes to be maintained. For a transmission route, the configuration includes at least one of the destination BAP address and the path identifier.

[0186] ◆Maintain one or more of the above configuration instructions

[0187] ■ Information about the type of data to be maintained. This information indicates the type of data that the first node can continue to transmit after migration (or configuration update) using the configuration used before migration (or configuration update). In one embodiment, if the first node migrates, this information indicates the type of data that needs to be maintained on the source path. This information may include at least one of the following:

[0188] ◆All data, such as F1 interface data, non-F1 interface data, F1 interface control plane data, F1 interface user plane data, etc.

[0189] ◆Control plane data of F1 interface, such as F1-C traffic

[0190] User plane data of the F1 interface, such as F1-U traffic

[0191] ◆Non-F1 interface data, such as non-F1 traffic

[0192] ◆Control plane data of the F1 interface associated with the user, such as UE-associated F1-C traffic

[0193] ◆Control plane data of the F1 interface associated with non-users, such as non-UE-associated F1-C traffic

[0194] ◆BAP layer control data, such as BAP Control PDU

[0195] Uplink data

[0196] ◆Downlink data

[0197] ◆Retention instruction information, which is used to instruct the above one or more types of data to continue to be transferred using the configuration used before migration (or configuration update)

[0198] ■ Maintain the indication information of the source path. The purpose of this indication information is that when the first node migrates, the first node can continue to maintain communication with the nodes on the source path, as well as the configuration information required to support this communication. Furthermore, this "communication with the nodes on the source path" can be communication through a backhaul link channel, and the "configuration information required to support this communication" can be BAP configuration, backhaul link channel configuration, address (such as IP address, BAP address) configuration, tunnel configuration, etc.

[0199] ■ Information about the length of time the configuration needs to be maintained, which indicates the length of time the above configuration needs to be maintained

[0200] Based on the aforementioned "relevant configuration information to be maintained," the first node can maintain its pre-migration (or configuration update) configuration during the migration process (configuration update process) or after the migration (or configuration update), thereby utilizing this configuration information to transmit data with nodes connected before the migration (or configuration update) (e.g., other relay nodes, and / or anchor nodes, and / or nodes on the source path). Optionally, prior to step 1-1, the fourth node can also obtain information for configuring the first node for migration, including obtaining information for configuring the first node for migration from other nodes and / or generating information for configuring the first node for migration by the fourth node.

[0201] Step 1-2: (Optional) The first node sends a first response message to the fourth node. The first response message may be a first configuration request response message. The function of this message is to confirm to the fourth node that the first node has received the above-mentioned first message, and further, to confirm that the first node has completed the configuration contained in the first message.

[0202] Step 1-3: The first node transmits data according to the first message in step 1-1. In this step, the first node may transmit data in one or more of the following ways during the migration process (or configuration update process) and / or after the migration (after the configuration update):

[0203] ■ The first node transmits data through the node it was connected to before migration (or configuration update). In one embodiment, the node it was connected to is a node in the source path used before migration. The first node can transmit data based on the "relevant information retained in the configuration" included in step 1-1.

[0204] ■The first node transmits data through the node to which it is connected after migration (or configuration update). In one embodiment, the connected node is a node in the target path used after migration. The data transmitted through the target path may be ultimately sent to a third node. The data transmitted through the target path may also be ultimately sent to the second node. In this manner, the data transmitted through the target path may be directly or indirectly sent by the first node to the distribution unit of the anchor node on the target path, and then sent by the distribution unit of the anchor node on the target path to the second node, or sent by the second node to the distribution unit of the anchor node on the target path, and then sent by the distribution unit of the anchor node on the target path directly or indirectly to the first node.

[0205] The beneficial effects of the above process are:

[0206] 1) During the migration process (or configuration update process), the relay node can maintain communication with the source path (or the path before the configuration update), thereby avoiding or reducing the interruption and delay of user data transmission

[0207] 2) After migration (configuration update), the relay node can send user data through the target path used after migration (configuration update), thereby avoiding or reducing the interruption and delay of user data transmission.

[0208] To further illustrate the beneficial effects of executing the above steps 1-1 and 1-2, the following is an explanation with reference to a specific embodiment:

[0209] Example 1-1 (Configuring the First Node to Perform Data Transmission on the Target Path)

[0210] In this embodiment, the first node can communicate with the second node to which it was connected before migration by using the target path. The process involved is as follows:

[0211] Step 1-1-1: The fourth node sends a first message to the first node. The fourth node can be the node to which the first node was connected before migration (such as the second node mentioned above) or the node to which the first node was connected after migration (such as the third node mentioned above). The second node and the third node can be the same node or different nodes. The first message includes at least one of the following information:

[0212] ■For information related to the backhaul link, refer to "Information related to the backhaul link" in step 1-1 above.

[0213] ■ For the address-related information required by the first node, refer to the "Address-related information" in step 1-1 above.

[0214] Step 1-1-2: (Optional) The first node sends a first response message to the fourth node.

[0215] Step 1-1-3: The first node transmits data with the second node or the third node on the target path, for example, Figure 4 (a) shows an example in which a first node transmits data with a second node or a third node on a target path according to an embodiment of the present invention.

[0216] ■ The first node transmits data to the second node or the third node according to the "default backhaul link configuration information" in step 1-1-1. The data may be non-user plane data (such as control plane data of the F1 interface, data of non-F1 interface) and / or user plane data of the F1 interface.

[0217] ■ The first node transmits uplink data with the second node or the third node according to the "default backhaul link configuration information" in step 1-1-1. The data can be non-user plane data (such as control plane data of the F1 interface, non-F1 interface data) and / or user plane data of the F1 interface.

[0218] ■ The first node transmits downlink data with the second node or the third node according to the "default backhaul link configuration information" in step 1-1-1. The data can be non-user plane data (such as control plane data of the F1 interface, non-F1 interface data) and / or user plane data of the F1 interface.

[0219] During data transmission, the address used by the first node may be the "information related to the address required by the first node" configured in step 1-1-1, or the address used by the first node before migration (or configuration update).

[0220] The beneficial effect of this embodiment is that, during the migration process, the first node can maintain data transmission with the second node via the target path, thereby reducing the data transmission delay during the migration of the first node or avoiding interruption of data transmission during the migration of the first node. The data transmission can occur before a tunnel or transport layer association is established between the first node and the third node and a corresponding backhaul link is configured.

[0221] Example 1-2 (Configuring the First Node to Maintain Data Transmission on the Source Path)

[0222] In this embodiment, during or after the migration, the relay node can transmit data with the second node via the source path. The process included in this embodiment is as follows:

[0223] Step 1-2-1: The fourth node sends a first message to the first node. The fourth node can be the node to which the first node was connected before migration (such as the second node described above) or the node to which the first node was connected after migration (such as the third node described above). The second node and the third node can be the same node or different nodes. The first message includes at least one of the following information:

[0224] ■ For the address-related information required by the first node, refer to the "Address-related information" in step 1-1 above.

[0225] ■For information about configuration retention, please refer to the "Related information about configuration retention" in step 1-1 above.

[0226] Step 1-2-2: (Optional) The first node sends a first response message to the fourth node.

[0227] Step 1-2-3: The first node transmits data with the second node on the source path, for example, Figure 4 (b) shows an example of the first node transmitting data with the second node on the source path according to an embodiment of the present application.

[0228] ■The first node transmits data with the second node according to the "configured information about to be kept" in step 1-2-1, which can be non-user plane data (such as control plane data of F1 interface, data of non-F1 interface) and / or user plane data of F1 interface

[0229] ■The first node transmits downlink data with the second node according to the "configured information about to be kept" in step 1-2-1, which can be non-user plane data (such as control plane data of F1 interface, data of non-F1 interface) and / or user plane data of F1 interface

[0230] ■The first node transmits uplink data with the second node according to the "configured information about to be kept" in step 1-2-1, which can be non-user plane data (such as control plane data of F1 interface, data of non-F1 interface) and / or user plane data of F1 interface

[0231] In addition, because the first node can have established a connection with the third node, in step 1-2-3 above, the first node can also transmit data with the third node using the target path.

[0232] During the data transmission, the address used by the first node side can be the "information about the address required by the first node" configured in step 1-2-1, or the address used by the first node before migration (or before configuration update).

[0233] The beneficial effect of this embodiment is that, during migration, the first node can maintain data transmission with the second node through the source path, thereby reducing the latency of data transmission during the migration of the first node, or avoiding the interruption of data transmission during the migration of the first node. The data transmission can occur before the establishment of a tunnel or a transport layer association between the first node and the third node and the configuration of the corresponding backhaul link.

[0234] Embodiment 1-3 (the first node transmits data through the source path and the target path)

[0235] This embodiment simultaneously uses the source path and the target path for data transmission, and the process it contains is as follows:

[0236] Step 1-3-1: The fourth node sends a first message to the first node. The fourth node can be the node to which the first node was connected before migration (such as the second node mentioned above) or the node to which the first node is connected after migration (such as the third node mentioned above). The second node and the third node can be the same node or different nodes. The first message includes at least one of the following information:

[0237] ■For information related to the backhaul link, refer to "Information related to the backhaul link" in step 1-1 above.

[0238] ■ For the address-related information required by the first node, refer to the "Address-related information" in step 1-1 above.

[0239] ■For information about configuration retention, please refer to the "Related information about configuration retention" in step 1-1 above.

[0240] Step 1-3-2: (Optional) The first node sends a first response message to the fourth node.

[0241] Step 1-3-3: The first node performs data transmission with the second node or the third node on the source path and the target path, for example, Figure 4 (c) shows an example in which the first node transmits data with the second node or the third node on the source path and the target path according to an embodiment of the present invention.

[0242] ■ The first node performs data transmission with the second node on the target path according to the "default backhaul link configuration information" in step 1-3-1. The data may be non-user plane data (such as control plane data of the F1 interface, data of non-F1 interface) and / or user plane data of the F1 interface.

[0243] ■ The first node transmits uplink data with the second node on the target path according to the "default backhaul link configuration information" in step 1-3-1. The data can be non-user plane data (such as control plane data of the F1 interface, non-F1 interface data) and / or user plane data of the F1 interface.

[0244] ■ The first node transmits downlink data with the second node on the target path according to the "default backhaul link configuration information" in step 1-3-1. The data can be non-user plane data (such as control plane data of the F1 interface, non-F1 interface data) and / or user plane data of the F1 interface.

[0245] ■ The first node transmits data with the second node on the source path according to the "configuration and maintenance related information" in step 1-3-1. The data can be non-user plane data (such as control plane data of the F1 interface, data of non-F1 interface) and / or user plane data of the F1 interface.

[0246] ■ The first node transmits downlink data to the second node on the source path according to the "configuration of the retained relevant information" in step 1-3-1, which can be non-user plane data (such as control plane data of the F1 interface, data other than the F1 interface) and / or user plane data of the F1 interface

[0247] ■ The first node transmits uplink data to the second node on the source path according to the "configuration of the retained relevant information" in step 1-3-1, which can be non-user plane data (such as control plane data of the F1 interface, data other than the F1 interface) and / or user plane data of the F1 interface

[0248] In addition, since the first node can have established a connection with the third node, in step 1-3-3, the first node can also transmit data to the third node using the target path.

[0249] During the data transmission, the address used by the first node side can be the "address relevant information required by the first node" configured in step 1-3-1, or the address used by the first node before the migration (or before the configuration update).

[0250] The beneficial effect of this embodiment is that, during the migration, the first node can maintain data transmission with the second node through the source path and the target path, thereby reducing the latency of data transmission during the migration of the first node, or avoiding the interruption of data transmission during the migration of the first node. The data transmission can occur before the establishment of the tunnel or the transport layer association between the first node and the third node and the configuration of the corresponding backhaul link.

[0251] If the relay node is in the process of migration, its mobile terminal part can be switched according to the existing Dual Active Protocol Stack (DAPS) mechanism. In this mechanism, after receiving the RRC message for switching, the mobile terminal part of the user or relay node still maintains the connection with the control plane part of the source base station / source anchor node / source anchor node's centralized unit / source anchor node's centralized unit. When the mobile terminal part of the user or relay node successfully accesses the control plane part of the target base station / target anchor node / target anchor node's centralized unit / target anchor node's centralized unit (the control plane part of the target anchor node / target anchor node's centralized unit / target anchor node's centralized unit may be the same as the control plane part of the source anchor node / source anchor node's centralized unit / source anchor node's centralized unit), it will disconnect from the control plane part of the source base station / source anchor node / source anchor node's centralized unit / source anchor node's centralized unit. In one embodiment, during the process of accessing a node on a target path, the mobile terminal part can maintain uplink and downlink data transmission with the source path. After the mobile terminal part successfully accesses a node on the target path, such as after completing the random access process, the mobile terminal part can maintain downlink data transmission with the source path, but uplink data transmission needs to be carried out through the target path). In this way, according to the first aspect of the present invention, the relay node can use the source path to maintain the reception of user data, such as the reception of downlink data, and at the same time, can use the target path to send data, such as sending uplink data to a second node or a third node. One implementation method is to send user-side data to the second node and send non-user-side data to the third node.

[0252] Figure 5 FIG. 4 shows an example of a migration process of a first node according to an embodiment of the present invention. Figure 5 As shown, if the second node and the third node are two different nodes during the migration of the first node, the following process may also be included:

[0253] Step 1-a-1: The second node sends a second message to the third node. The second message may be the first handover request message, which includes information requesting the first node's migration configuration. This message sends the first node's configuration information to the third node, facilitating the third node's generation of the first node's post-migration configuration information. The content of this message can refer to the HANDOVER REQUEST message in TS38.423 and / or TS36.423. In addition, this message may include at least one of the following information:

[0254] ■Configuration information of the first node. The information contained in this information can be found in the above “ User configuration information (or user context information) ”

[0255] ■ Request information related to the address of the first node, which is used to send information related to the address of the first node to the third node, or to send information to the third node requesting the third node to configure an address for the first node, and includes at least one of the following information:

[0256] ■ Address request information, which is used to request the third node to configure the address of the first node. This information includes at least one of the following information:

[0257] ■The number of addresses requested, which can be either IPv4 or IPv6 addresses. The requested addresses can be used for all types of data transmission.

[0258] ■Indication of the purpose of the requested address. The purpose indicated by the indication information may be one or more of the following purposes: transmission of F1-C traffic, transmission of F1-U traffic, transmission of non-F1 traffic, etc.

[0259] ■Request the number of addresses used for F1-C traffic. The addresses can be either IPv4 or IPv6 addresses.

[0260] ■Request the number of addresses used for F1-U traffic. The address can be either an IPv4 address or an IPv6 address.

[0261] ■Request information about the number of addresses used for non-F1 traffic. The addresses can be either IPv4 or IPv6 addresses.

[0262] ■ Address request indication information, which indicates to the third node whether a new address is needed. The address can be an IPv4 address, an IPv6 address, or a prefix of an IPv6 address. This information includes at least one of the following:

[0263] ■ Request information indicating the address for data transmission

[0264] ■Request information indicating the address to be used for F1-C traffic

[0265] ■ Request information about the address to be used for F1-U traffic

[0266] ■Request information about the address used for non-F1 traffic

[0267] ■ Address information used on the source path. This information is used to inform the third node of address-related information used by the first node on the source path. This information may include one or more addresses. For each address, this information includes at least one of the following:

[0268] ■Address index information, such as Address Index

[0269] ■Address information, such as IPv4 address, IPv6 address, IPv6 prefix

[0270] ■Address information used for F1-C traffic, such as IPv4 address, IPv6 address, and IPv6 prefix

[0271] ■Address information used for F1-U traffic, such as IPv4 address, IPv6 address, and IPv6 prefix

[0272] ■Address information for non-F1 traffic, such as IPv4 address, IPv6 address, and IPv6 prefix

[0273] ■ Indication of the purpose of the address, which may be one or more of the following purposes: transmission of F1-C traffic, transmission of F1-U traffic, transmission of non-F1 traffic, etc.

[0274] ■ Request to keep the above address indication information, the role of this information is that the second node requests the third node to keep the address used on the source path. Further, this indication information can be given for each address separately or for all addresses. That is, if this indication information is included, it means that the second node requests to keep all addresses used on the source path.

[0275] The beneficial effect of this information is to help the third node to know the address information required by the first node, so that the third node can determine the address configured for the first node for the target path based on this information. Another beneficial effect is to help the third node to update the address used by the first node.

[0276] ■ Information related to a backhaul link of the first node, where the backhaul link is a backhaul link served by a mobile terminal portion of the first node. In one embodiment, the backhaul link is a backhaul link used on a source path, and the information includes at least one of the following information:

[0277] ■ Information related to the backhaul link channel. The backhaul link may include one or more backhaul link channels. For each backhaul link channel, the information includes at least one of the following information:

[0278] ◆Backhaul link channel identification information

[0279] QoS information of the backhaul link channel, which can be found in TS 38.473

[0280] Indication information of the request to reserve the backhaul link channel, which is used by the second node to request the third node to reserve the backhaul link channel on the source path

[0281] Indication information of the request to reserve all backhaul link channels, which is used by the second node to request the third node to reserve all backhaul link channels on the source path

[0282] Indication information of the request to reserve the configuration, which is used by the second node to request the reservation of the configuration on the source path, which can include one of the following information:

[0283] Indication information of the request to reserve the configuration on the source path, further, the configuration can be the configuration required by the service of the first node or the distributed unit part of the first node on the source path, which includes the configuration of the mobile terminal part of the first node (such as BAP configuration, backhaul link channel configuration, etc.) and the configuration of the distributed unit part (such as the configuration of the tunnel, the configuration of the transport layer association, the information of the backhaul link, the configuration of the address, etc.), such as Keep BAP Request, Keep Source BHlink Request, etc. The indication information can be an explicit indication or an implicit indication. As an example, the indication information can be implicitly indicated by DAPS Indicator (TS 38.423), but it needs to be noted that this way extends the role of DAPS Indicator IE in the traditional technology and changes the behavior of the receiving node. In the traditional technology, DAPS Indicator IE is given for a DRB, that is, the DRB containing the IE requests to configure the DRB as a DAPS bearer, and the receiving node decides whether to accept the request. However, in the present application, if the second node receives the configuration information of at least one DRB containing the DAPS Indicator IE, it implicitly notifies the second node that the first node requests to reserve the configuration required by the service of the first node or the distributed unit part of the first node on the source path (such as BAP configuration, and / or backhaul link channel configuration, configuration of the tunnel, configuration of the transport layer association, information of the backhaul link, configuration of the address, etc.)

[0284] Indication information of the request to reserve the backhaul link channel, which is used by the second node to request the third node to reserve the backhaul link channel on the source path

[0285] ■ Instruction information requesting to maintain the configuration of the mobile terminal part of the first node, which indicates that the first node requests to maintain the configuration used by the mobile terminal part to transmit data on the source path. The configuration of the mobile terminal part may include BAP configuration and / or backhaul link channel configuration, etc.

[0286] ■ Instruction information requesting to maintain the configuration of the distribution unit part of the first node, which indicates that the first node requests to maintain the configuration used by the distribution unit part to transmit data on the source path. The configuration of the distribution unit part may include tunnel configuration, transport layer association configuration, backhaul link information, address configuration, etc.

[0287] ■ Information indicating the configuration requested to be maintained, which indicates that the second node requests to maintain the configuration required to serve the first node or the distributed unit portion of the first node on the source path. The configuration requested to be maintained can be one or more of the following configurations:

[0288] ◆BAP configuration, which includes at least one of the following information: 1) the BAP address of the first node, 2) the default routing identification information, 3) the identification information of the default return link channel

[0289] BAP address

[0290] ◆Default routing identification information

[0291] ◆Default backhaul link channel identification information

[0292] ◆ Identification information of the backhaul link channel. The first node will be configured with one or more backhaul link channels on the source path. This information provides the identification information of one or more backhaul link channels that need to be maintained. Furthermore, this information also implicitly indicates the configuration information of the data transmitted on the channel that needs to be maintained, such as the tunnel configuration, such as the transport layer association configuration, etc.

[0293] Tunnel configuration information, which indicates the configuration of the tunnel that needs to be maintained. The tunnel can be an uplink tunnel or a downlink tunnel. For a tunnel, the configuration information includes at least one of the following information:

[0294] Tunnel identification information

[0295] Tunnel information, such as the IP address and / or GTP-U TEID, where the IP address is the IP address of one end of the tunnel

[0296] Downlink tunnel information, such as an IP address and / or GTP-U TEID. The IP address may be an IP address on the first node side (such as an address on the distribution unit side of the first node).

[0297] • information of uplink tunnel, such as IP address and / or GTP-U TEID, the IP address can be the address at the side of the anchor node (or the centralized unit of the anchor node or the user plane part of the centralized unit of the anchor node)

[0298] ◆ configuration information of transport layer association, which indicates the configuration of the transport layer association that needs to be maintained, and the information includes at least one of the following information:

[0299] • identification information of the transport layer association

[0300] • information of the transport layer association, such as IP address and / or port, the IP address is the IP address of one end of the transport layer association

[0301] • information of downlink transport layer association, such as IP address and / or port, the IP address can be the IP address at the side of the first node (such as the address at the side of the distributed unit part of the first node)

[0302] • information of uplink transport layer association, such as IP address and / or port, the IP address can be the address at the side of the anchor node (or the centralized unit of the anchor node or the user plane part of the centralized unit of the anchor node)

[0303] ◆ configuration information of address, which indicates the address that needs to be maintained, the address can be an IP address, and can be a BAP address

[0304] ◆ configuration of transport route, which indicates the transport route that needs to be maintained, and the transport route that needs to be maintained can be one or more, for one transport route, the configuration includes at least one of the following information: destination BAP address and path identifier

[0305] ■ load-related information of the first node, which is used to inform the third node of the load of the first node, so as to help the third node to perform access control, and the information includes at least one of the following information:

[0306] ■ information of the number of users accessing the first node

[0307] ■ information of the number of bearers served by the first node

[0308] ■ information related to the backhaul link channel configured by the mobile terminal part of the first node, which can include identification information of the backhaul link channel, QoS information of the backhaul link channel, etc.

[0309] ■ indication information of hardware load (such as hardware load indicator (Hardware Load Indicator)), which indicates the load of the hardware, such as DL / UL hardware load indicator (DL / UL Hardware Load Indicator)

[0310] ■ an indication of the transport network layer capacity (e.g. TNL Capacity indicator) indicating the capacity that the transport network can offer or available, which can include one of the following: offered DL / UL TNL capacity, available DL / UL TNL capacity, etc.

[0311] ■ information of the cell load of the first node, which can include at least one of the following:

[0312] ◆ identification information of the cell

[0313] ◆ radio resource status information indicating the usage of the physical resources of the cell, which can include one of the following: synchronization signaling block index, indication of the resource usage for serving DL / UL GBR (Guaranteed Bit Rate) traffic in the SSB area (e.g. SSB Area DL / UL GBR PRB usage), indication of the resource usage for serving DL / UL non-GBR traffic in the SSB area (e.g. SSB Area DL / UL non-GBR PRB usage), indication of the resource usage for serving DL / UL traffic in the SSB area (e.g. SSB Area DL / UL total PRB usage), DL / UL scheduling PDCCH CCE usage

[0314] ◆ available capacity information (e.g. Composite Available Capacity Group) indicating the level of total available DL / UL resources per cell or per SSB area. This can include one of the following: DL / UL Composite Available Capacity

[0315] Slice Available Capacity, which indicates the amount of resources each network slice has relative to the cell's resources. This information may include one of the following: Slice indication information (such as S-NSSAI), the amount of uplink / downlink resources available for the slice (such as the Slice Available Capacity Value UL / DL).

[0316] Number of Active UEs, which indicates the average number of active UEs.

[0317] Step 1-a-2: The third node sends a second response message to the second node. The second response message may be the first handover request response message, and the second response message includes information for configuring the migration of the first node. This message is used to configure the migration of the first node and / or send the configuration information generated by the third node for serving the first node to the second node. The content included in this message can refer to the HANDOVER REQUESTACKNOWLEDGE message in TS38.423 and / or TS36.423. In addition, this message may include one of the following information:

[0318] ■ Feedback information related to the address of the first node, which is used to configure address-related information for the first node. The information includes at least one of the following:

[0319] ■ Information about the address configured for the first node, which includes at least one of the following:

[0320] Information about the newly added or updated address of the first node, including at least one of the following:

[0321] ●Address index information, such as Address Index

[0322] ●Address information, such as IPv4 address, IPv6 address, and IPv6 prefix

[0323] Address information for F1-C traffic, such as IPv4 address, IPv6 address, and IPv6 prefix

[0324] Address information for F1-U traffic, such as IPv4 address, IPv6 address, and IPv6 prefix

[0325] Address information for non-F1 traffic, such as IPv4 address, IPv6 address, and IPv6 prefix

[0326] Indication of the purpose of the address, which may be one or more of the following: transmission of F1-C traffic, transmission of F1-U traffic, transmission of non-F1 traffic, etc.

[0327] The address information of the distribution unit of the anchor node corresponding to the above address, such as Donor DU BAP Address

[0328] Information about the address that the first node needs to release, including at least one of the following:

[0329] Address index information, such as Address Index, which indicates the address that needs to be released

[0330] ■The setting value information of the IP packet, which can indicate the setting value of the DSCP field and / or flow label field in the IP packet. In one embodiment, the information can be given separately for each address included in the above-mentioned "information of the address configured by the first node", that is, one such information is configured for each address, and then the second node sets the DSCP field and / or flow label field of the IP packet to the value indicated by the information when sending data to the first node. In another embodiment, the information can be given for one or more or all addresses included in the above-mentioned "information of the address configured by the first node", and then the second node can set the DSCP field and / or flow label field of the IP packet to the value indicated by the information when sending data to the one or more or all addresses of the first node. As an example, the information can be named default QoS mapping information, default DSCP, default flow label, etc.

[0331] One beneficial effect of this information is that after the second node sets the IP packet according to the information, the IP packet can be sent to the first node via the target path. Furthermore, after the distribution unit of the anchor node on the target path receives the IP packet, it will determine the information used to send the data packet based on the destination IP address and / or the setting value of the DSCP field and / or the setting value of the Flow Label field contained in the IP packet, such as the return link channel, the default return link channel, the address of the next hop node receiving the data packet (such as the BAP address), the routing identifier that needs to be added to the data packet (such as the BAP routing ID, including the BAP address and the path identifier), the identifier of the transmission route of the data packet (such as the BAP routing ID, including the BAP address and the path identifier), etc.

[0332] ■ A response message for retaining the configuration. This message notifies the second and third nodes whether they have accepted the configuration requested to be retained as indicated in the "indication message for requesting to retain the configuration" in step 1-a-1. Furthermore, the message may indicate the configuration to be retained. This message includes at least one of the following information:

[0333] ■Indication of approval of the request, which includes at least one of the following:

[0334] ◆Accept the instruction information for retaining the configuration on the source path. Further, this information may be a response to the "instruction information for requesting to retain the configuration on the source path" included in step 1-a-1

[0335] ◆Accept the instruction information for maintaining the backhaul link channel. Further, this information may be a response to the "instruction information for requesting to maintain the backhaul link channel" included in step 1-a-1

[0336] ◆Accept the instruction information for maintaining the configuration of the mobile terminal part of the first node. Further, the information may be a response to the "instruction information for requesting to maintain the configuration of the mobile terminal part of the first node" included in step 1-a-1

[0337] ◆Accept the instruction information for maintaining the configuration of the distributed unit portion of the first node. Further, the information may be a response to the "instruction information for requesting to maintain the configuration of the distributed unit portion of the first node" included in step 1-a-1.

[0338] ◆Accept the indication information of the maintained configuration. Further, this information may be a response to the "indication information of requesting the maintained configuration" included in step 1-a-1

[0339] ■ The retained configuration information, which is used to notify the second node, or the first node (in this case, the third node sends the second response message to the second node, which then sends it to the first node) of the retained configuration information. The content of this information can be found in the "Related information about configuration retention" in the first message in step 1-1 above.

[0340] ■ Configuration information related to the first node's backhaul link. This information is used to configure the backhaul link channel used by the first node on the target path. This information includes at least one of the following: RLC layer configuration information, logical channel configuration information, etc. For details, see CellGroupConfig in TS38.331

[0341] ■Information related to starting user context migration, which is used to inform the second node to start the context migration of the user served by the first node, and the information includes at least one of the following information:

[0342] ■Indication information of starting user context migration, which is used to inform the second node to start the migration of the user context

[0343] ■Identification information of the relay node accessed by the user, such as the BAP address of the relay node, the identification of the distribution unit part of the relay node, etc.

[0344] ■Information of the number of users allowed to be admitted

[0345] ■Information of the number of radio bearers of the user allowed to be admitted

[0346] ■Clock information of starting migration, which indicates the time to be waited before starting the migration

[0347] ■Indication information of admitting user migration, which is used to inform the second node whether to continue the migration of the user context, and the information includes at least one of the following information:

[0348] ■Indication information of stopping user context migration, after receiving the information, the second node will stop the migration of the user context

[0349] ■Information of the number of users that can still be admitted, after receiving the information, the second node can select appropriate users for context migration

[0350] ■Reason information, such as insufficient resources, or other reasons

[0351] Further, the flow can further include the following steps:

[0352] Step 1-a-3: (Optional) The second node sends a first message to the first node, which is used to provide the first node with configuration information required for migration, and the content included in the message can be referred to the first message in step 1-1 above.

[0353] Step 1-a-4: (Optional) The first node sends a first response message to the second node or the third node, and the content included in the message can be referred to the first response message in step 1-2 above.

[0354] The beneficial effect of the above procedure is that the anchor node of the source path and the anchor node of the target path can interact the related information of the relay node during the migration of the relay node, so as to determine the configuration information of the migration of the relay node. Specifically, it can be determined whether to retain one or more configurations on the source path, it can be determined the retained one or more configurations on the source path, and it can be determined one or more configurations on the target path. Another beneficial effect is that the second node and / or the third node can determine the configuration of the data transmission with the first node on the source path and / or the target path. Another beneficial effect is that after the above procedure, the second node and / or the third node maintain the data transmission with the first node, thereby reducing the interruption or delay of data transmission of the relay node during the migration.

[0355] In addition, when the first node migrates, a possible implementation is that the second node performs data transmission with the first node using the address used by the first node before migration, and the transmitted data is transmitted through the distribution unit (fifth node) of the anchor node on the target path after the first node accesses the target path (after completing random access). In this implementation, the fifth node can not know the address (such as IP address) used by the first node before migration, so it can discard the data packet sent to or from the first node. In order to avoid this situation, the present application further provides an address notification mechanism, the main function of which is to notify the distribution unit of the anchor node on the target path of the address (such as IP address) of the first node. Figure 6 An example of notifying the distribution unit of the anchor node on the target path of the address of the first node according to an embodiment of the present application is shown as Figure 6 The mechanism includes the following procedure as shown in the figure:

[0356] Step 1-b-1: The fourth node sends a third message to the fifth node, and the third message can be a third configuration request message, the function of which is to notify the address information used by the first node. The fourth node can be the node connected by the first node before migration (such as the second node described above), or the node connected by the first node after migration (such as the third node described above). The second node and the third node can be the same node or different nodes, and the message includes at least one of the following information:

[0357] ■Identification information of the first node, such as gNB-DU ID, etc.

[0358] ■Address-related information, which includes at least one of the following information:

[0359] ■Address index information, such as Address Index

[0360] ■Address information, such as IPv4 address, IPv6 address, IPv6 prefix

[0361] ■Address information used for F1-C traffic, such as IPv4 address, IPv6 address, and IPv6 prefix

[0362] ■Address information used for F1-U traffic, such as IPv4 address, IPv6 address, and IPv6 prefix

[0363] ■Address information for non-F1 traffic, such as IPv4 address, IPv6 address, and IPv6 prefix

[0364] ■ Indication of the purpose of the address, which may be one or more of the following purposes: transmission of F1-C traffic, transmission of F1-U traffic, transmission of non-F1 traffic, etc.

[0365] In one embodiment, the address information is the address information used by the first node before migration. Receiving this information advantageously allows the fifth node to determine that the data packet containing the address information is a data packet of the first node it serves. Furthermore, the fifth node will continue to forward the data packet without discarding it.

[0366] Step 1-b-2: (Optional) The fifth node sends a third response message to the fourth node. The third response message may be a third configuration request response message, which is used to confirm the message sent in step 1-b-1.

[0367] In the above description, the first message and the first response message may be RRCReconfiguration and RRCReconfigurationComplete messages respectively, or may be other RRC messages, or may be messages of the F1 interface respectively.

[0368] The second message and the second response message may be HANDOVER REQUEST and HANDOVER REQUEST ACKNOWLEDGE messages of the X2 or Xn interface, respectively, or other messages.

[0369] The third message and the third response message may be the IAB TNL ADDRESS REQUEST and IAB TNL ADDRESS RESPONSE messages of the F1 interface respectively, or may be other messages of the F1 interface.

[0370] The steps (step 1-1, 1-2, 1-3, 1-a-1, 1-a-2, 1-a-3, 1-a-4, 1-b-1, 1-b-2) in the above procedure can be performed independently or in combination with each other.

[0371] The second aspect of the application

[0372] In the process of migration of the relay node, the users accessing the relay node can also migrate with the relay node. When the relay node migrates from one node (source node) to another node (target node), the context of the users accessing the relay node also needs to be migrated to the target node. To solve this problem, possible methods include group handover, i.e. when performing migration of the relay node, the users accessing the node are switched to the target node through group handover. In such a method, due to the limitation of the message size of the X2 / Xn interface, it is not possible to perform switching of all users in one message. Another method is to switch the users one by one to the target node according to the conventional user switching method. The problem of this method is that it causes a large amount of signaling overhead, which can cause a large switching delay. In addition, a common problem of the two methods is that each user needs to be switched in the air interface (the interface between the user and the relay node), which further causes a large amount of air interface signaling overhead and a larger switching delay. Therefore, to solve this problem, the application proposes a method for user context migration. Figure 7 An example of a method for user context migration according to an embodiment of the application is shown as follows, Figure 7 The method includes the following procedure:

[0373] Step 2-1: The second node sends a fourth message to the third node, the fourth message can be a first user configuration request message, and the fourth message includes user configuration information. The function of the message is to transmit user configuration information and / or send the context of the user to the third node, and the message can be used to send the context of one or more users, and the message includes at least one of the following information:

[0374] ■First information related to the configuration of the user, which can include configuration information of one or more users, and for one user, the information contained in the information can refer to the HANDOVER REQUEST message in TS38.423 or TS36.423, in addition, one or more of the above "user configuration information" can be included, in addition, one of the following information can also be included: User configuration information (or user context information)

[0375] ​■ Cell first identification information, which indicates the cell configured for the user by the second node before migration (i.e., when the user accesses the second node). This message may include one or more cells, which may be a special cell (SpCell), a primary cell (PCell), a primary secondary cell (PSCell), or a secondary cell (SCell). For a cell, this information includes at least one of the following:

[0376] NR CGI / NCGI (NR Cell Global Identifier)

[0377] Physical Cell Identifier (PCI)

[0378] Base station identification information (such as Global NG-RAN Node ID, or gNB ID)

[0379] ■ First configuration information related to user data, which is used to inform the transmission status of the user's radio bearer at the second node. For a user's radio bearer, this information includes at least one of the following information:

[0380] ■ Radio bearer identification information

[0381] Uplink data transmission status information, which includes at least one of the following:

[0382] ◆Indication information of the reception status of uplink PDCP layer data packets (such as PDCP SDUs), which indicates the uplink PDCP layer data packets correctly received at the second node, and / or the PDCP layer data packets that were incorrectly received. In one embodiment, the information can be a bit string (bitmap), where the first bit indicates the first incorrectly received PDCP SDU, and the subsequent bits indicate the reception status of each PDCP SDU after the PDCP SDU (such as 1 for correct reception and 0 for incorrect reception).

[0383] ◆ Sequence number of the first incorrectly received PDCP SDU (PDCP-SN)

[0384] Hyperframe number of the first incorrectly received PDCP SDU

[0385] ■ Downlink data transmission status information, which includes at least one of the following:

[0386] ◆The PDCP sequence number required for the first PDCP SDU that has not been assigned a PDCP sequence number

[0387] ◆The superframe number required for the first PDCP SDU that has not been assigned a PDCP sequence number. In the above information, the PDCP sequence number can be 12 bits or 18 bits long.

[0388] Furthermore, the above-mentioned “first information related to user configuration” may also be for multiple users.

[0389] ■Indication information of the purpose of the message, which is used to inform the third node of the purpose of the fourth message containing the indication information, and includes at least one of the following information:

[0390] ■ User context migration indication information, which is used to inform the third node that the fourth message containing the indication information is used to migrate the user context (i.e., from the second node to the third node). An example of the name of this information is Context Migration Indication, and it can also be other names.

[0391] ■ No Handover Indication information, which is used to inform the third node that the fourth message containing the indication information is not for handover. An example of the name of this information is No Handover Indication, and it can also be other names

[0392] ■ Ignore information indication information, which is used to inform the third node that if the fourth message contains the indication information, the third node can ignore some information in the fourth message, such as the target cell global identifier (TargetCell Global ID); an example of the name of this information is Ignore Handover IEsIndication, which can also be other names

[0393] ■Reason information, which indicates the reason for sending the fourth message, such as context migration, IAB / relay node migration, base station change, donor node change, etc.

[0394] The indication information of the message usage is beneficial to help the third node to understand the information in the fourth message and to help the third node to set the information in the fourth response message. In one embodiment, the third node can ignore one or more information elements (IEs) in the fourth message, such as the Target Cell Global ID. Meanwhile, the third node can also set the information in the fourth response message according to the indication information when it replies the fourth response message in step 2-2, such as not setting the configuration information of the user's random access, such as not including the RRC container information related to handover, etc. In addition, if the second node includes the indication information, the second node can also determine how to handle the information in the fourth response message according to the indication information after it receives the fourth response message in step 2-2, such as ignoring some information in the message (such as the RRC container information).

[0395] ■Information related to migration, which is used to help the third node to determine whether the migration is completed, and the information includes at least one of the following information:

[0396] ■Indication information of the end of migration, which indicates that the contexts of all users on the second node have been migrated, and after receiving the indication information, the third node can consider that the second node will not send the fourth message to migrate the context of the user again

[0397] ■Indication information of the number of users that have not been migrated, which indicates the number of users whose contexts need to be continued to be migrated

[0398] Step 2-2: The third node sends a fourth response message to the second node, which can be a first user configuration request response message. The function of the message is to inform the configuration of the user at the third node, and the message can include the configuration of one or more users, and the message includes at least one of the following information:

[0399] ■Second information related to the configuration of the user, which can include the configuration information of one or more users, and for one user, the information includes the configuration of the user decided by the third node, and the content included in the information can refer to the HANDOVER REQUEST ACKNOWLEDGE message in TS 38.423 or TS 36.423, in addition, one or more of the information included in the above "Information related to migration" can also be included, in addition, one of the following information can also be included: use User configuration information (or user context information)

[0400] ​■Second identity information of the cell, the cell identified by the information is the cell serving the user. The cell serving the user is the cell of the third node; in one embodiment, the migration of the user context is because the relay node accessed by the user has migrated (from the second node to the third node), which causes the change of the cell served by the relay node (such as the change of the cell identity). The information can include the identity of one or more cells, which can be a special cell (SpCell), a primary cell (PCell), a primary secondary cell (PSCell), a secondary cell (SCell), and for one cell, the information includes at least one of the following information:

[0401] ◆Cell global identifier, NR CGI / NCGI (NR Cell Global Identifier)

[0402] ◆Physical cell identifier (PCI)

[0403] ◆Base station identification information (such as global NG-RAN node identifier (Global NG-RAN Node ID), or gNB ID)

[0404] ■Indication information for reserving the configuration information of the user's radio bearer, which informs the second node to reserve the configuration information of the user's radio bearer to continue to serve the user, and for the radio bearer of one user, the information includes at least one of the following information:

[0405] ◆Identification information of the radio bearer

[0406] ◆Indication information for reserving the uplink tunnel of the user's radio bearer, which informs the second node that it can also receive user data on the uplink tunnel of the radio bearer

[0407] ◆Indication information for reserving the downlink tunnel of the user's radio bearer, which informs the second node that it can also send user data to the relay node on the downlink tunnel of the radio bearer, and further, it can also include the information added by the second node in the data packet when sending user data to the relay node, such as the setting value of the DSCP field and / or the setting value of the Flow Label field, which can help the second node to set the fields in the data packet, so as to ensure that the data packet sent by it can be finally sent to the relay node. The above-mentioned "second information related to the user configuration" can also be for multiple users.

[0408] ■ User migration indication information, which is used to inform the second node whether to continue migrating the user context. This information includes at least one of the following information:

[0409] ■ Instruction message to stop user context migration. After receiving this message, the second node will stop the migration of user context.

[0410] ■ Information about the number of users that can be accommodated. After receiving this information, the second node can select the appropriate user for context migration

[0411] ■Reason information, such as insufficient resources, may also be other reasons

[0412] ■ Ignore information indication information, which is used to notify the second node to ignore certain information in the fourth response message, such as the RRC container included in the message. In one embodiment, the Target NG-RAN node To SourceNG-RAN node Transparent Container IE in the message is ignored.

[0413] The above process is different from the user switching process in the traditional technology (i.e., the switching preparation process performed by the HANDOVERREQUEST and HANDOVER REQUEST ACKNOWLEDGE messages on the X2 / Xn interface). This is because the user does not switch the serving cell in this process (it is still the cell on the relay node). Therefore, in step 2-1, there is no need to include information related to the target cell (such as the identification information of the target cell, the target cell is the cell of the third node. In one embodiment, the target cell is the cell after the relay node migrates to the third node), nor is there any need to include configuration information related to random access. However, some new information will also need to be included, such as the configuration information related to the user's wireless bearer tunnel and the information related to the return link required for the wireless bearer tunnel serving the user. For details, please refer to the above " User configuration information (or user context information) Therefore, the fourth message and the fourth response message in the above process may be newly defined messages on the Xn / X2 interface. The message may be a user-related message (only one user context is migrated at a time). Examples of the message names may be UE Context Migration Request / Response, Group Context Migration Request / Response, etc.

[0414] In another embodiment, the fourth message and the fourth response message in the above procedure can also be existing messages, such as the HANDOVER REQUEST and HANDOVER REQUEST ACKNOWLEDGE messages on the X2 / Xn interface. However, as described above, the user context migration is different from the user handover, some IEs in the existing HANDOVER REQUEST message can not be needed, or the third node can ignore some IEs in the message, therefore, an indication information needs to be added in the HANDOVER REQUEST message to indicate that the purpose of sending the message is not for handover, or to indicate that the purpose of sending the message is for user context migration, an example of the added indication information is the "message usage indication information" contained in step 2-1 above, after receiving the indication information, the third node will not understand the procedure as a handover procedure, but as a context migration procedure, and then the third node can have some behaviors different from the handover preparation procedure, such as ignoring some IEs. After receiving the indication information, the third node can also be different from the existing handover preparation procedure when setting the HANDOVER REQUEST ACKNOWLEDGE message, such as the third node can not modify the user configuration information, the third node can not configure the user with random access related configuration, etc., the third node can add an "ignore information indication information" in the message to inform the second node to ignore some information in the message.

[0415] In another embodiment, the fourth message and the fourth response message in the above procedure can also be existing messages, such as the HANDOVER REQUEST and HANDOVER REQUEST ACKNOWLEDGE messages on the X2 / Xn interface, and the above procedure is equivalent to the existing user handover preparation procedure, and the difference from the existing procedure is that some new information is added in the HANDOVER REQUEST and HANDOVER REQUEST ACKNOWLEDGE messages, which can be used to interact the user context information between the second node and the third node. Further, after step 2-2, the procedure can also include that the second node or the third node sends an RRCReconfiguration message to the user accessing the first node (the user is the user to which the above HANDOVER REQUEST and HANDOVER REQUEST ACKNOWLEDGE messages are directed), and the user accessing the first node sends an RRCReconfigurationComplete message to the second node or the third node.

[0416] In another embodiment, the fourth message and the fourth response message in the above process may also be non-user-related messages (migrating the context of one or more users at a time), then the process can be used to migrate the context of multiple users at a time, and examples of the message names may be Group Context Migration Request / Response, etc.

[0417] The above process has the beneficial effect of migrating a user's context from one node to another. Furthermore, during the migration process, a user configuration update may or may not be required. Another beneficial effect is that during the relay node migration process, the user context migration is not performed simultaneously with the handover of the mobile terminal portion of the relay node, thereby saving signaling overhead, reducing user data transmission latency, and avoiding interruption of user data transmission.

[0418] In addition to the above process, optional, Figure 8 The embodiment of the present invention is shown in Figure 7 Examples of processes that can also be included before step 2-1 include: Figure 8 As shown:

[0419] Step 2-1a: The third node sends a fifth message to the second node. The fifth message may be a second user configuration request message. The function of the message is to notify the second node to start migrating the user context. The message includes at least one of the following information:

[0420] ■ Instruction information for starting user context migration, which is used to notify the second node to start user context migration

[0421] ■ Identification information of the relay node to which the user is connected, such as the BAP address of the relay node, the identification of the distribution unit of the relay node, etc.

[0422] ■Information on the number of users allowed to be accepted

[0423] ■ Information on the number of radio bearers allowed to be admitted to a user

[0424] ■Clock information for starting migration, which indicates the time to wait before starting migration

[0425] Step 2-1b: (Optional) The second node sends a fifth response message to the third node. The fifth response message may be a second user configuration request response message, which serves to confirm receipt of the fifth message in the above step 2-1a.

[0426] In another embodiment, step 2-1a may also occur during user context migration. In this case, sending the fifth message is used to notify the second node of information related to the user context migration. The fifth message may further include at least one of the following information:

[0427] ■ User migration indication information, which is used to inform the second node whether to continue migrating the user context. This information includes at least one of the following information:

[0428] ■ Instruction message to stop user context migration. After receiving this message, the second node will stop the migration of user context.

[0429] ■ Information about the number of users that can be accommodated. After receiving this information, the second node can select the appropriate user for context migration

[0430] ■Reason information, such as insufficient resources, may also be other reasons

[0431] The fifth message and the fifth response message in the above process can be messages of the newly defined X2 / Xn interface or existing messages. The message can be a non-user-related message or a user-related message. An example of the message name can be a UE Context Migration Trigger Request / Response message or other message. In another embodiment, step 2-1b can be excluded from the above process.

[0432] The beneficial effect of the above process is that the third node can notify the second node to migrate the user context according to the access status of the relay node, thus ensuring the success of the migration.

[0433] also, Figure 9 The embodiment of the present invention is shown in Figure 7 An example of a process that may also be included after the above step 2-2 is as follows: Figure 9 As shown:

[0434] Step 2-2a: The second node sends a sixth message to the third node. The sixth message may be a third user configuration request message. The function of the message is to notify the third node that the migration of the user context has ended. The message includes at least one of the following information:

[0435] ■Indication of the end of user context migration

[0436] Second configuration information related to user data, which is used to inform the user of the transmission status of the radio bearer at the second node. For a radio bearer of a user, this information includes at least one of the following information:

[0437] ■ Radio bearer identification information

[0438] ■ Uplink data transmission status information, which includes at least one of the following:

[0439] ◆Indication information of the reception status of uplink PDCP layer data packets (such as PDCP SDUs), which indicates the uplink PDCP layer data packets correctly received at the second node, and / or the PDCP layer data packets that were incorrectly received. In one embodiment, the information can be a bit string (bitmap), where the first bit indicates the first incorrectly received PDCP SDU, and the subsequent bits indicate the reception status of each PDCP SDU after the PDCP SDU (such as 1 for correct reception and 0 for incorrect reception).

[0440] ◆ Sequence number of the first incorrectly received PDCP SDU (PDCP-SN)

[0441] Hyperframe number of the first incorrectly received PDCP SDU

[0442] ■ Downlink data transmission status information, which includes at least one of the following:

[0443] ◆The PDCP sequence number required for the first PDCP SDU that has not been assigned a PDCP sequence number

[0444] ◆The superframe number required for the first PDCP SDU that has not been assigned a PDCP sequence number. In the above information, the PDCP sequence number can be 12 bits or 18 bits long.

[0445] Step 2-2b: (Optional) The third node sends a sixth response message to the second node. The sixth response message may be a third user configuration request response message, which confirms receipt of the sixth message in the above step 2-2a.

[0446] The sixth message and sixth response message in the above process may be messages of the newly defined X2 / Xn interface or existing messages. The message may be a non-user-related message or a user-related message. An example of the message name may be a UE Context Migration Complete Request / Response message or other message. In another embodiment, step 2-2b may be excluded from the above process.

[0447] The beneficial effect of the above process is that the second node can notify the third node that the migration of the user context has been completed, which helps the third node determine the information in the source node for releasing the service user.

[0448] also, Figure 10 An example of a process that may be included after completing the migration of the user context according to an embodiment of the present invention is shown. Figure 10 As shown:

[0449] Step 2-3: The third node sends a seventh message to the second node. The seventh message may be the fourth user configuration request message. The function of the message is to notify the second node to release the configuration information related to the user and / or relay node. The message includes at least one of the following information:

[0450] ■ Relay node identification information, such as gNB-ID, BAP address, etc.

[0451] ■Instructions for releasing user context

[0452] ■Instruction information for releasing the relay node's context

[0453] ■Instructions for releasing the source path configuration

[0454] After receiving the above message, the second node may release the relevant configuration of serving the relay node, and may also release the relevant configuration of the user accessing the relay node.

[0455] Optionally, the method further includes step 2-4: the second node sends a seventh response message to the third node. The seventh response message may be the fourth user configuration request response message. The seventh response message is used to confirm receipt of the seventh message. Furthermore, the message may include at least one of the following information:

[0456] ■ Third configuration information related to user data, which is used to inform the transmission status of the user's radio bearer at the second node. For a user's radio bearer, this information includes at least one of the following information:

[0457] ■ Radio bearer identification information

[0458] ■ Uplink data transmission status information, which includes at least one of the following:

[0459] ◆Indication information of the reception status of uplink PDCP layer data packets (such as PDCP SDUs), which indicates the uplink PDCP layer data packets correctly received at the second node, and / or the PDCP layer data packets that were incorrectly received. In one embodiment, the information can be a bit string (such as a bitmap), the first bit indicates the first incorrectly received PDCP SDU, and the subsequent bits indicate the reception status of each PDCP SDU after the PDCP SDU (such as 1 for correct reception and 0 for incorrect reception).

[0460] ◆ Sequence number of the first incorrectly received PDCP SDU (PDCP-SN)

[0461] Hyperframe number of the first incorrectly received PDCP SDU

[0462] ■ Downlink data transmission status information, which includes at least one of the following:

[0463] ◆The PDCP sequence number required for the first PDCP SDU that has not been assigned a PDCP sequence number

[0464] ◆The superframe number required for the first PDCP SDU that does not have a PDCP sequence number assigned to it

[0465] The seventh message and seventh response message in the above process can be messages of the newly defined X2 / Xn interface or existing messages. The message can be a non-user-related message or a user-related message. Examples of the message name can be a Migration Success Request / Response message, a Source Path Release Request / Response message, or other messages.

[0466] Optionally, the method may further include step 2-5: the second node or the third node sends an eighth message to the first node, where the eighth message may be a fifth user configuration request message, and the message is used to notify the first node to release configuration information related to the user and / or relay node, and the message includes at least one of the following information:

[0467] ■ Relay node identification information, such as gNB-ID, BAP address, etc.

[0468] ■Instructions for releasing user context

[0469] ■Instruction information for releasing the relay node's context

[0470] ■Instructions for releasing the source path configuration

[0471] Step 2-5 can be performed independently, or after step 2-3 or step 2-4.

[0472] The beneficial effect of the above process is that the third node can notify the second node to release the context of the relay node and / or user, as well as the relevant configuration and resources on the source path, so that the second node can provide more resources to other users. Another beneficial effect is that the second node or the third node can notify the first node to release the context of the relay node and / or user, as well as the relevant configuration and resources on the source path, so that the first node can provide more resources to other users.

[0473] Each step in the above process (steps 2-1, 2-2, 2-1a, 2-1b, 2-2a, 2-2b, 2-3, 2-4, and 2-5) can be performed independently or in combination. In one embodiment, the following steps can be included:

[0474] ■Step 1: The third node sends the fifth message to the second node, see step 2-1a above

[0475] ■Step 2: (Optional) The second node sends a fifth response message to the third node, see step 2-1b above.

[0476] ■Step 3: The second node sends a fourth message to the third node, see step 2-1 above

[0477] ■Step 4: The third node sends a fourth response message to the second node, see step 2-2 above

[0478] The above steps 3 / 4 can be performed continuously to migrate the user's context

[0479] ■Step 5: The second node sends the sixth message to the third node, see step 2-2a above

[0480] ■Step 6: (Optional) The third node sends a sixth response message to the second node, see step 2-2b above.

[0481] ■Step 7: The third node sends the seventh message to the second node, see steps 2-3 above

[0482] ■Step 8: Optionally, the second node sends a seventh response message to the third node, see steps 2-4 above.

[0483] ■Step 9: Optionally, the second node or the third node sends an eighth message to the first node, see steps 2-5 above.

[0484] The process of the first aspect and the process of the second aspect of the present invention may also be combined with each other. In one embodiment, the process may include the following:

[0485] ■Step 1: The second node sends a second message to the third node, see step 1-a-1 above

[0486] ■Step 2: The third node sends a second response message to the second node, see step 1-a-2 above

[0487] ■Step 3: The fourth node sends the first message to the first node, see step 1-1 above

[0488] ■Step 4: (Optional) The first node sends a first response message to the fourth node, see steps 1-2 above

[0489] ■Step 5: The third node sends a fifth message to the second node, see step 2-1a above

[0490] ■Step 6: (Optional) The second node sends a fifth response message to the third node, see step 2-1b above.

[0491] ■Step 7: The second node sends a fourth message to the third node, see step 2-1 above

[0492] ■Step 8: The third node sends a fourth response message to the second node, see step 2-2 above

[0493] The above steps 7 / 8 can be performed continuously to migrate the user's context

[0494] ■Step 9: The second node sends the sixth message to the third node, see step 2-2a above

[0495] ■Step 10: (Optional) The third node sends a sixth response message to the second node, see step 2-2b above.

[0496] ■Step 11: The third node sends the seventh message to the second node, see steps 2-3 above

[0497] ■Step 12: (Optional) The second node sends a seventh response message to the third node, see steps 2-4 above.

[0498] ■Step 13: (Optional) The second node or the third node sends an eighth message to the first node, see steps 2-5 above.

[0499] ■

[0500] 1) Effects of the Invention

[0501] Based on the invention of the first aspect, the beneficial effects are:

[0502] 1) During the migration process (or configuration update process), the relay node can maintain communication with the source path (or the path before the configuration update), thereby avoiding or reducing the interruption and delay of user data transmission

[0503] 2) After migration (configuration update), the relay node can send user data through the target path used after migration (configuration update), thereby avoiding or reducing the interruption and delay of user data transmission.

[0504] Based on the invention of the second aspect, the beneficial effects are:

[0505] 1) The user's context can be migrated between base stations without requiring the user to switch, saving signaling overhead and reducing switching delay

[0506] 2) In a multi-hop relay network, the configuration and resources of the source path can be released in time, effectively utilizing the wireless resources on the node

[0507] Figure 11 1 is a block diagram of an anchor node according to an embodiment of the present invention. Here, the structure and function of the anchor node are described as an example, but it should be understood that the structure and function shown are also applicable to a base station or a distribution unit of the anchor node.

[0508] refer to Figure 11 , the anchor node 1100 includes a transceiver 1110, a controller 1120, and a memory 1130. Under the control of the controller 1120 (which may be implemented as one or more processors), the anchor node 1100 (including the transceiver 1110 and the memory 1130) is configured to execute Figure 3 、 Figures 5 to 10 The operations of the anchor node in the illustrated process or described above include, but are not limited to, the operations of the source anchor node and the target anchor node. Although the transceiver 1110, the controller 1120, and the memory 1130 are shown as separate entities, they may be implemented as a single entity, such as a single chip. The transceiver 1110, the controller 1120, and the memory 1130 may be electrically connected or coupled to each other. The transceiver 1110 may send signals to and receive signals from other network entities, such as another anchor node, a relay node, and / or a UE. In one embodiment, the transceiver 1110 may be omitted. In this case, the controller 1120 may be configured to execute instructions (including computer programs) stored in the memory 1130 to control the overall operation of the anchor node 1100, thereby implementing Figure 3 、 Figures 5 to 10 The operations of the anchor node in the process shown or described above.

[0509] Figure 12 is a block diagram of a relay node according to an embodiment of the present invention.

[0510] refer to Figure 12 , the relay node 1200 includes a transceiver 1210, a controller 1220 and a memory 1230. Under the control of the controller 1220 (which can be implemented as one or more processors), the relay node 1200 (including the transceiver 1210 and the memory 1230) is configured to execute Figure 3 、 Figure 5 The operations of the relay node in the process shown or described above. Although the transceiver 1210, the controller 1220 and the memory 1230 are shown as separate entities, they can be implemented as a single entity, such as a single chip. The transceiver 1210, the controller 1220 and the memory 1230 can be electrically connected or coupled to each other. The transceiver 1210 can send signals to and receive signals from other network entities, such as anchor nodes, another relay node and / or UEs. In one embodiment, the transceiver 1210 can be omitted. In this case, the controller 1220 can be configured to execute instructions (including computer programs) stored in the memory 1230 to control the overall operation of the relay node 1200, thereby performing Figure 3 、 Figure 5 The operations of the relay node in the process shown or described above.

[0511] Those skilled in the art will recognize that the present invention can be implemented in other specific forms without changing the technical ideas or basic features of the present invention. Therefore, it should be understood that the above embodiments are merely examples and are not limiting. The scope of the present invention is defined by the appended claims, rather than by the detailed description. Therefore, it should be understood that all modifications or variations derived from the meaning and scope of the appended claims and their equivalents are within the scope of the present invention.

[0512] In the above-described embodiments of the present invention, all operations and messages may be selectively performed or omitted. Furthermore, the operations in each embodiment need not be performed sequentially, and the order of operations may vary. Messages need not be transmitted sequentially, and the order in which messages are transmitted may vary. Each operation and each message transmission may be performed independently.

[0513] While the invention has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.

Claims

1. A method performed by a first integrated access backhaul (IAB) anchor node in a communication system, the method comprising: Sending a request message to the second IAB anchor node, the request message including first information related to the first address allocated to the relay node and address request information indicating a request for address allocation; as well as A response message in response to the request message is received from the second IAB anchor node, the response message including second information related to a second address allocated to the relay node.

2. The method according to claim 1, wherein The first address allocated to the relay node includes at least one of the following: an Internet Protocol (IP version 4) IPv4 address allocated to the relay node or an IP version 6 (IPv6) address allocated to the relay node.

3. The method according to claim 1, wherein The request for address allocation includes at least one of the following: a request for Internet Protocol (IP version 4) address allocation, or a request for IP version 6 (IPv6) address allocation.

4. The method according to claim 1, wherein The request for address allocation includes at least one of the following: information about the number of addresses requested for all data flow traffic, information about the number of addresses requested for F1-C data flow, information about the number of addresses requested for F1-U data flow, or information about the number of addresses requested for non-F1 data flow.

5. The method according to claim 1, wherein The second information includes at least one of the following: an Internet Protocol (IP) version 4 (IPv4) address assigned to the relay node, an IP version 6 (IPv6) address assigned to the relay node, information indicating usage of the IPv4 address or the IPv6 address, or an address of an IAB anchor node distribution unit (DU).

6. The method according to claim 1, further comprising: The second address is sent to the relay node.

7. The method according to claim 1, wherein An IAB transport network layer (TNL) address request message is sent from the second IAB anchor node to the DU of the second IAB anchor node, the IAB TNL address request message including third information related to a third address allocated to the relay node.

8. The method according to claim 7, wherein: The third address allocated to the relay node includes at least one of: an Internet Protocol (IP) version 4 (IPv4) address allocated to the relay node, or an IP version 6 (IPv6) address allocated to the relay node.

9. The method according to claim 7, wherein: The third address assigned to the relay node is the first address assigned to the relay node.

10. The method according to claim 7, wherein: The data packet including the third address allocated to the relay node is forwarded by the DU of the second IAB anchor node.

11. A method performed by a second integrated access backhaul (IAB) anchor node in a communication system, the method comprising: receiving a request message from the first IAB anchor node, the request message including first information related to a first address allocated to the relay node and address request information indicating a request for address allocation; as well as In response to the request message, a response message is sent to the first IAB anchor node, where the response message includes second information related to the second address allocated to the relay node.

12. The method according to claim 11, wherein The first address allocated to the relay node includes at least one of: an Internet Protocol (IP version 4) IPv4 address allocated to the relay node, or an IP version 6 (IPv6) address allocated to the relay node.

13. The method according to claim 11, wherein The request for address allocation includes at least one of the following: a request for Internet Protocol (IP version 4) IPv4 address allocation or a request for IP version 6 (IPv6) address allocation.

14. The method according to claim 11, wherein The request for address allocation includes at least one of: information regarding the number of addresses requested for all data flows, information regarding the number of addresses requested for F1-C data flows, information regarding the number of addresses requested for F1-U data flows, or information regarding the number of addresses requested for non-F1 data flows.

15. The method according to claim 11, wherein The second information includes at least one of the following: an Internet Protocol (IP) version 4 (IPv4) address assigned to the relay node, an IP version 6 (IPv6) address assigned to the relay node, information indicating usage of the IPv4 address or the IPv6 address, or an address of an IAB anchor node distribution unit (DU).

16. The method according to claim 11, further comprising: An IAB transport network layer (TNL) address request message is sent to the DU of the second IAB anchor node, wherein the IAB TNL address request message includes third information related to a third address allocated to the relay node.

17. The method according to claim 16, wherein The third address allocated to the relay node includes at least one of: an Internet Protocol (IP) version 4 (IPv4) address allocated to the relay node, or an IP version 6 (IPv6) address allocated to the relay node.

18. The method according to claim 16, wherein The third address assigned to the relay node is the first address assigned to the relay node.

19. The method according to claim 16, wherein The data packet including the third address allocated to the relay node is forwarded by the DU of the second IAB anchor node.

20. The method according to claim 11, wherein The second address is sent by the first IAB anchor node to the relay node.

21. A first integrated access backhaul (IAB) anchor node, comprising: memory for storing computer programs; as well as A controller configured to execute the computer program to implement the method according to any one of claims 1 to 10.

22. A second integrated access backhaul (IAB) anchor node, comprising: memory for storing computer programs; as well as A controller configured to execute the computer program to implement the method according to any one of claims 11 to 20.

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