Node in wireless communication system and method performed by same

Abstract

The present disclosure provides a node in a wireless communication system and a method performed by the same. A method performed by a first node in a wireless communication system includes: transmitting a third message to a third node, the third message including information about a list of serving cells that the first node expects to activate and an F1 traffic profile; receiving, from the third node, a fourth message in response to the third message, the fourth message comprising an acceptable F1 traffic profile and information of a cell to be activated; and sending a sixth message to the second node, where the sixth message comprises information of the activated cell and an acceptable F1 traffic profile.

Description

Technical Field

[0001] The present disclosure relates to the technical field of wireless communications, and more particularly, to a node in a wireless communication system and a method executed by the node. Background Art

[0002] In order to meet the increased demand for wireless data communication services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or quasi-5G communication systems. Therefore, 5G or quasi-5G communication systems are also referred to as "super 4G networks" or "post-LTE systems."

[0003] The demand for wireless data services is growing rapidly due to the increasing popularity of smartphones and other mobile data devices (e.g., tablets, laptops, netbooks, e-book readers, and machine-type devices) among consumers and enterprises. In order to meet the high growth of mobile data services and support new applications and deployments, it is critical to improve the efficiency and coverage of the wireless interface.

[0004] In 5G communication technology, because of the use of higher frequencies, it has a faster transmission speed than 4G; but the higher frequency also leads to a shorter transmission distance, so more base stations will be deployed in the 5G network to ensure the coverage of the 5G network. But in fact, some areas cannot deploy normal 5G base stations due to environmental or cost reasons, so IAB (integrated access and backhaul) technology is proposed to make up for the problem of 5G base stations not being able to cover these areas and ensure normal communication for users. In the current research on IAB networks, the process of establishing the IAB network, partial migration, and the transmission process of data packets in the IAB network have been determined; next, a more in-depth study will be conducted on the movable IAB nodes and IAB-DU migration. Summary of the invention

[0005] An embodiment of the present disclosure provides a method performed by a first node in a wireless communication system, comprising: sending a third message to a third node, wherein the third message includes information about a list of service cells that the first node expects to activate and an F1 service profile; receiving a fourth message in response to the third message from the third node, wherein the fourth message includes an acceptable F1 service profile and information about cells to be activated; and sending a sixth message to a second node, wherein the sixth message includes information about the activated cells and an acceptable F1 service profile.

[0006] According to an embodiment of the present disclosure, the method further includes: receiving a first message from the second node, wherein the first message includes an F1 service profile.

[0007] According to an embodiment of the present disclosure, the method also includes: sending a second message to a fourth node, wherein the second message includes at least one of the following: a transmission network layer TNL address of a second DU of the first node, a node identifier and / or IP address of the third node, and information indicating that the first node is about to perform a distribution unit DU migration.

[0008] According to an embodiment of the present disclosure, the method further includes: sending a fifth message to a fourth node, wherein the fifth message includes a mobile integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the third node for the first node.

[0009] According to an embodiment of the present disclosure, the method also includes: receiving a seventh message from the second node, wherein the seventh message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a node identifier and / or IP address of a new target F1 termination anchor node CU; sending an eighth message to the third node, wherein the eighth message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a reason value for cancelling the successfully established F1 connection between the first node and the third node; and receiving a ninth message from the third node, wherein the ninth message includes information indicating that the third node agrees to cancel the successfully established F1 connection between the first node and the third node.

[0010] According to an embodiment of the present disclosure, the first message is sent from the second node when the second node receives the tenth message from the operation administration and maintenance OAM node, wherein the tenth message includes at least one of the following: information indicating that the first node performs distribution unit DU migration, the node identifier and / or IP address of the third node.

[0011] According to an embodiment of the present disclosure, the method also includes: receiving an eleventh message from an operation administration and maintenance OAM node, wherein the eleventh message includes at least one of the following: information indicating that the first node performs distribution unit DU migration, a node identifier and / or an IP address of the third node; and sending a twelfth message to the second node, wherein the twelfth message includes the node identifier and / or the IP address of the third node.

[0012] According to an embodiment of the present disclosure, the first message is sent from the second node when the second node agrees that the distributed unit DU of the first node is migrated to the third node.

[0013] According to an embodiment of the present disclosure, the method also includes: receiving an eleventh message from an operation administration and maintenance OAM node, wherein the eleventh message includes at least one of the following: information indicating that the first node performs distribution unit DU migration, the node identifier and / or IP address of the third node; receiving a thirteenth message from the fourth node, wherein the thirteenth message includes at least one of the following: a removable integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the fourth node for the first node, and a node identifier of the fourth node; and sending a fifth message to the fourth node, wherein the fifth message includes the removable integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the third node for the first node.

[0014] According to an embodiment of the present disclosure, the information about the list of service cells that the first node expects to activate is indicated by one or more of the following methods: indicated by a first information element in an F1 establishment request, wherein the first information element indicates a list of service cells that the first node expects to activate; indicated by status information corresponding to each service cell in the service cell list; or indicated by a second information element in the F1 establishment request, wherein the second information element indicates whether the cells in the service cell list are all service cells that the first node expects to activate.

[0015] According to an embodiment of the present disclosure, the method also includes: in case the sending of the sixth message fails, sending a fourteenth message to the third node, wherein the fourteenth message includes at least one of the following: information for indicating that the source F1 connection between the first node and the second node is disconnected, information indicating that the third node sends the sixth message to the second node, and information indicating that the third node notifies the second node that the source F1 connection between the first node and the second node is disconnected.

[0016] An embodiment of the present disclosure provides a method performed by a second node in a wireless communication system, comprising: sending a first message to a first node, wherein the first message includes an F1 service profile; and receiving a sixth message from the first node, wherein the sixth message includes information of an activated cell and an acceptable F1 service profile.

[0017] According to an embodiment of the present disclosure, the method further includes: in a case where the distributed unit DU of the first node is allowed to migrate to the third node, executing a user equipment context switching process.

[0018] According to an embodiment of the present disclosure, the method also includes: sending a seventh message to the first node, wherein the seventh message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a node identifier and / or IP address of a new target F1 termination anchor node CU.

[0019] According to an embodiment of the present disclosure, the method also includes: receiving a tenth message from an operation administration and maintenance OAM node, wherein the tenth message includes at least one of the following: information instructing the first node to perform distribution unit DU migration, a node identifier and / or IP address of a third node, wherein the first message is sent to the first node when the second node receives the tenth message.

[0020] According to an embodiment of the present disclosure, the method also includes: receiving a twelfth message from the first node, wherein the twelfth message includes a node identifier and / or IP address of a third node, wherein the node identifier and / or IP address of the third node is received by the first node from an operation administration and maintenance OAM node.

[0021] According to an embodiment of the present disclosure, the first message is sent from the second node when the second node agrees that the distributed unit DU of the first node is migrated to the third node.

[0022] According to an embodiment of the present disclosure, the method also includes: in case of failure to receive the sixth message from the first node, receiving a fifteenth message from the third node, wherein the fifteenth message includes at least one of the following: information indicating that the F1 connection between the first node and the third node is successfully established, information indicating that the source F1 connection between the first node and the second node is disconnected, a target cell identifier, information on activated cells, and an acceptable F1 service profile.

[0023] An embodiment of the present disclosure provides a method performed by a third node in a wireless communication system, comprising: receiving a third message from a first node, wherein the third message includes information about a list of service cells that the first node expects to activate and an F1 service profile; and sending a fourth message to the first node, wherein the fourth message includes an acceptable F1 service profile and information about the cell to be activated.

[0024] According to an embodiment of the present disclosure, the method also includes: receiving an eighth message from the first node, wherein the eighth message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a reason value for cancelling the successfully established F1 connection between the first node and the third node; and sending a ninth message to the first node, wherein the ninth message includes information indicating that the third node agrees to cancel the successfully established F1 connection between the first node and the third node, wherein the eighth message is sent from the first node when the first node receives a seventh message from the second node, wherein the seventh message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a node identifier and / or IP address of a new target F1 termination anchor node CU.

[0025] According to an embodiment of the present disclosure, the information about the list of service cells that the first node expects to activate is indicated by one or more of the following methods: indicated by a first information element in an F1 establishment request, wherein the first information element indicates a list of service cells that the first node expects to activate; indicated by status information corresponding to each service cell in the service cell list; or indicated by a second information element in the F1 establishment request, wherein the second information element indicates whether the cells in the service cell list are all service cells that the first node expects to activate.

[0026] According to an embodiment of the present disclosure, the method also includes: receiving a fourteenth message from the first node, wherein the fourteenth message includes at least one of the following: information indicating that the source F1 connection between the first node and the second node is disconnected, information indicating that the third node sends a sixth message to the second node, and information indicating that the third node notifies the second node that the source F1 connection between the first node and the second node is disconnected, wherein the fourteenth message is sent from the first node when the first node fails to send the sixth message to the second node.

[0027] According to an embodiment of the present disclosure, the method also includes: sending a fifteenth message to the second node, wherein the fifteenth message includes at least one of the following: information indicating that the F1 connection between the first node and the third node is successfully established, information indicating that the source F1 connection between the first node and the second node is disconnected, a target cell identifier, information about the activated cell, and an acceptable F1 service profile.

[0028] An embodiment of the present disclosure provides a method performed by a fourth node in a wireless communication system, comprising: receiving a second message from a first node, wherein the second message includes at least one of the following: a transport network layer TNL address of a second distribution unit DU of the first node, a node identifier and / or IP address of a third node, and information indicating that the first node is about to perform distribution unit DU migration; and receiving a fifth message from the first node, wherein the fifth message includes a mobile integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the third node for the first node.

[0029] According to an embodiment of the present disclosure, the method also includes: sending a thirteenth message to the first node, wherein the thirteenth message includes at least one of the following: a mobile integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the fourth node for the first node, and a node identifier of the fourth node.

[0030] An embodiment of the present disclosure provides a node device in a wireless communication system, comprising: a transceiver; and a processor, coupled to the transceiver and configured to execute any method performed by a first node and / or a second node and / or a third node and / or a fourth node in the wireless communication system according to an embodiment of the present disclosure.

[0031] An embodiment of the present disclosure provides a computer-readable medium having computer-readable instructions stored thereon, which, when executed by a processor, implement any method performed by a first node and / or a second node and / or a third node and / or a fourth node in a wireless communication system according to an embodiment of the present disclosure.

[0032] The method provided by the present disclosure and performed by the first node and / or the second node and / or the third node and / or the fourth node in the wireless communication system can realize DU migration of the movable IAB node. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0034] Figure 1 is an exemplary system architecture of System Architecture Evolution (SAE);

[0035] Figure 2 is an exemplary system architecture according to various embodiments of the present disclosure;

[0036] Figure 3a An exemplary structure of a base station according to an embodiment of the present disclosure is shown;

[0037] Figure 3bAn exemplary structure of a base station according to an embodiment of the present disclosure is shown;

[0038] Figure 3c An exemplary structure of a base station according to an embodiment of the present disclosure is shown;

[0039] Figure 4a An example case where an IAB-MT and an IAB-DU migrate from the same source IAB anchor node CU to the same target IAB anchor node CU is shown;

[0040] Figure 4b An example case where the IAB-MT and the IAB-DU migrate from the same source IAB anchor node CU to different target IAB anchor nodes CU is shown;

[0041] Figure 4c An example case where an IAB-MT and an IAB-DU migrate from different source IAB anchor nodes CU to the same target IAB anchor node CU is shown;

[0042] Figure 4d An example case where the IAB-MT and the IAB-DU migrate from different source IAB anchor nodes CU to different target IAB anchor nodes CU is shown;

[0043] Figure 5 An example flow chart showing the process of source F1 terminating anchor node CU triggering mIAB node to initiate DU migration;

[0044] Figure 6 An example flow chart showing a source F1 terminating anchor node CU changing a target F1 terminating anchor node CU;

[0045] Figure 7 An example case of OAM triggering DU migration process is shown;

[0046] Figure 8 An example flow chart of the OAM-triggered DU migration process is shown;

[0047] Fig. 9 An example flow chart of the OAM-triggered DU migration process is shown;

[0048] Fig.10 An example flow chart of the OAM-triggered DU migration process is shown;

[0049] Fig.11 An example of signaling enhancement of F1 setup request message is shown;

[0050] Fig.12 An example flow chart showing the successful establishment of a new F1 connection by notifying the source F1 terminating anchor node CU when a source link loss occurs;

[0051] Fig.13 Another example flow chart according to an embodiment of the present disclosure is shown;

[0052] Fig.14 Another example flow chart according to an embodiment of the present disclosure is shown;

[0053] Fig.15 A flowchart of a method performed by a first node in a wireless communication system according to an embodiment of the present disclosure is shown;

[0054] Fig.16 A flowchart of a method performed by a second node in a wireless communication system according to an embodiment of the present disclosure is shown;

[0055] Fig.17 A flowchart of a method performed by a third node in a wireless communication system according to an embodiment of the present disclosure is shown;

[0056] Fig.18 A flowchart of a method performed by a fourth node in a wireless communication system according to an embodiment of the present disclosure is shown; and

[0057] Fig.19 A schematic diagram of a node in a wireless communication system according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0058] The following description with reference to the accompanying drawings is provided to facilitate a comprehensive understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. This description includes various specific details to facilitate understanding but should be considered as exemplary only. Therefore, one of ordinary skill in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, for the sake of clarity and conciseness, descriptions of well-known functions and structures may be omitted.

[0059] The terms and expressions used in the following specification and claims are not limited to their dictionary meanings, but are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Therefore, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purposes only and not for the purpose of limiting the present disclosure as defined in the appended claims and their equivalents.

[0060] It should be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0061] The term "include" or "may include" refers to the presence of the corresponding disclosed functions, operations or components that can be used in various embodiments of the present disclosure, rather than limiting the presence of one or more additional functions, operations or features. In addition, the term "include" or "have" may be interpreted as indicating certain characteristics, numbers, steps, operations, constituent elements, components or combinations thereof, but should not be interpreted as excluding the possibility of the presence of one or more other characteristics, numbers, steps, operations, constituent elements, components or combinations thereof.

[0062] The term "or" used in various embodiments of the present disclosure includes any of the listed terms and all combinations thereof. For example, "A or B" may include A, may include B, or may include both A and B.

[0063] Unless defined differently, all terms (including technical terms or scientific terms) used in the present disclosure have the same meanings as understood by those skilled in the art described in the present disclosure. Common terms as defined in dictionaries are interpreted as having meanings consistent with the context in the relevant technical field, and should not be interpreted ideally or overly formally unless clearly defined in the present disclosure.

[0064] The accompanying drawings discussed below and the various embodiments used to describe the principles of the present disclosure in this patent document are for illustration only and should not be interpreted in any way as limiting the scope of the present disclosure. Those skilled in the art will appreciate that the principles of the present disclosure can be implemented in any suitably arranged system or device.

[0065] Figure 1 It is an exemplary system architecture 100 of System Architecture Evolution (SAE). User Equipment (UE) 101 is a terminal device used to receive data. Evolved Universal Terrestrial Radio Access Network (E-UTRAN) 102 is a radio access network, which includes a macro base station (eNodeB / NodeB) that provides a wireless network interface for the UE to access. The Mobility Management Entity (MME) 103 is responsible for managing the mobility context, session context and security information of the UE. The Serving Gateway (SGW) 104 mainly provides user plane functions, and the MME 103 and SGW 104 may be in the same physical entity. The Packet Data Network Gateway (PGW) 105 is responsible for functions such as billing and lawful interception, and may also be in the same physical entity as the SGW 104. The Policy and Charging Rules Function Entity (PCRF) 106 provides Quality of Service (QoS) policies and charging criteria. The General Packet Radio Service Support Node (SGSN) 108 is a network node device that provides routing for data transmission in the Universal Mobile Telecommunications System (UMTS). The Home Subscriber Server (HSS) 109 is the home subsystem of the UE and is responsible for protecting user information including the current location of the user equipment, the address of the service node, user security information, and the packet data context of the user equipment.

[0066] Figure 2 is an exemplary system architecture 200 according to various embodiments of the present disclosure. Other embodiments of the system architecture 200 can be used without departing from the scope of the present disclosure.

[0067] User equipment (UE) 201 is a terminal device used to receive data. Next generation radio access network (NG-RAN) 202 is a radio access network, which includes a base station (gNB or eNB connected to the 5G core network 5GC, the eNB connected to 5GC is also called ng-eNB) that provides the UE with an access wireless network interface. Access control and mobility management function (Access and Mobility Management Function, AMF) 203 is responsible for managing the mobility context and security information of the UE. User plane function (UPF) 204 mainly provides user plane functions. Session management function SMF 205 is responsible for session management. Data Network (Data Network, DN) 206 includes services such as operators, Internet access and third-party services.

[0068] In the NR system, in order to support network function virtualization, more efficient resource management and scheduling, the base station (gNB / ng-eNB) providing a wireless network interface for the terminal (UE) can be further divided into a centralized unit (e.g., gNB-CU / ng-eNB-CU (gNB central unit / ng-eNB central unit)) and a distributed unit (e.g., gNB-DU / ng-eNB-DU (gNB distributed unit / ng-eNB distributed unit)) (referred to as CU and DU in this disclosure), such as Figure 3aAs shown. gNB-CU has radio resource control (RRC), service data adaptation protocol (SDAP) and packet data convergence protocol (PDCP) protocol layers, and ng-eNB-CU has RRC and PDCP layers. gNB-DU / ng-eNB-DU has radio link control protocol (RLC), media access control (MAC) and physical layer (PHY), etc. There is a standardized public interface F1 between gNB-CU and gNB-DU, and a standardized public interface W1 between ng-eNB-CU and ng-eNB-DU. The F1 interface is divided into control plane F1-C and user plane F1-U. The transmission network layer of F1-C is based on IP transmission. In order to transmit signaling more reliably, the stream control transmission protocol (SCTP) protocol is added on top of IP. The protocol of the application layer is F1 Application Protocol (F1AP). SCTP can provide reliable application layer message transmission. The transport layer of F1-U is UDP / IP, and the GPRS tunneling protocol user plane (GTP-U) is used to carry the user plane protocol data unit PDU on top of UDP / IP. Furthermore, for gNB-CU, Figure 3bAs shown, the gNB-CU may include gNB-CU-CP (control plane part of the centralized unit of the base station) and gNB-CU-UP (user plane part of the centralized unit of the base station). The gNB-CU-CP includes the control plane function of the base station, and has RRC and PDCP protocol layers. The gNB-CU-UP includes the user plane function of the base station, and has SDAP and PDCP protocol layers. The standardized public interface E1 is used between the gNB-CU-CP and the gNB-CU-UP, and the protocol is the E1 Application Protocol (E1AP). The interface between the control plane part of the centralized unit of the base station and the distributed unit of the base station is the F1-C interface, i.e., the control plane interface of F1. The interface between the user plane part of the centralized unit of the base station and the distributed unit of the base station is the F1-U interface, i.e., the user plane interface of F1. In addition, in the NR system, the base station that provides the E-UTRA user plane and control plane accessing the 5G core network is called ng-eNB. In order to support virtualization, this base station (ng-eNB) can also be further divided into a centralized unit ng-eNB-CU (gNB central unit / ng-eNB central unit) and a distributed unit ng-eNB-DU (gNB distributed unit / ng-eNB distributed unit) (referred to as CU and DU in this disclosure), such as Figure 3c As shown. ng-eNB-CU has RRC and PDCP layers. gNB-DU / ng-eNB-DU has radio link control protocol (RLC), media access control (MAC) and physical layer, etc. There is a standardized public interface W1 between ng-eNB-CU and ng-eNB-DU. The W1 interface is divided into control plane W1-C and user plane W1-U. The transport network layer of W1-C is based on IP transmission. In order to transmit signaling more reliably, the SCTP protocol is added on top of IP. The protocol of the application layer is W1 Application Protocol (W1AP). The transport layer of W1-U is UDP / IP, and GTP-U is used to carry user plane protocol data unit PDU on top of UDP / IP.

[0069] The current research on IAB networks mainly determines the process of partial migration (or MTmigration). When an IAB node encounters a degradation in wireless performance, the source IAB anchor node CU (source IAB donor CU) can decide whether to perform partial migration based on the measurement report reported by the IAB node. If partial migration is performed, the IAB-MT (i.e., the RRC functional part) is migrated to the target IAB anchor node CU (target IAB donor CU); but the current research on IAB networks does not consider the mobility of IAB nodes, that is, the IAB nodes studied are all considered to be fixed. However, considering only fixed IAB nodes cannot meet people's needs for IAB networks, so it is necessary to study movable IAB nodes. When the IAB node is mobile, partial migration may not completely solve the problem of wireless performance degradation, so it is also necessary to study the process of DU migration, that is, not only the IAB-MT is migrated to the target IAB anchor node CU, but the IAB-DU (that is, the F1 connection with the anchor node CU) also needs to be migrated, so as to solve the problem of wireless performance degradation caused by the mobility of the IAB node.

[0070] Figure 4a An example case where an IAB-MT and an IAB-DU migrate from the same source IAB anchor node CU to the same target IAB anchor node CU is shown; Figure 4b An example case where the IAB-MT and the IAB-DU migrate from the same source IAB anchor node CU to different target IAB anchor nodes CU is shown; Figure 4c An example case where the IAB-MT and the IAB-DU migrate from different source IAB anchor nodes CU to the same target IAB anchor node CU is shown; Figure 4d An example case is shown where the IAB-MT and the IAB-DU migrate from different source IAB anchor nodes CU to different target IAB anchor nodes CU.

[0071] like Figure 4a-4d As shown, when the MT (mobile terminal) (mIAB-MT) and DU (mIAB-DU) of a mobile IAB node (mIAB node) are migrated, the following situations may occur:

[0072] Case 1: Migrate from the same source IAB anchor node CU to the same target IAB anchor node CU, such as Figure 4a As shown;

[0073] Case 2: Migrate from the same source IAB anchor node CU to a different target IAB anchor node CU, such as Figure 4b As shown;

[0074] Case 3: Migrate from different source IAB anchor nodes CU to the same target IAB anchor node CU, such as Figure 4c As shown;

[0075] Case 4: Migrate from different source IAB anchor nodes CU to different target IAB anchor nodes CU, such as Figure 4d shown.

[0076] Because MT migration and DU migration are decoupled from each other, in the above cases, only MT migration, only DU migration, MT migration before DU migration, and MT migration after DU migration are all possible. For the DU migration process, according to different initial states, that is, whether the anchor node CU anchored by MT and DU is the same, and whether the anchor node CU anchored by MT and DU is the same after DU migration is completed, there are three cases about DU migration:

[0077] Case 1: In the initial state, the anchor nodes CU anchored by MT and DU are the same. After the DU migration is completed, the anchor nodes CU anchored by MT and DU are different.

[0078] Case 2: In the initial state, the anchor nodes CU anchored by MT and DU are different. After the DU migration is completed, the anchor nodes CU anchored by MT and DU are the same.

[0079] Case 3: In the initial state, the anchor nodes CU anchored by the MT and the DU are different. After the DU migration is completed, the anchor nodes CU anchored by the MT and the DU are different.

[0080] One of the main technical problems solved by the present disclosure is to determine the DU migration process according to the above three DU migration situations, and the signaling design that needs to be enhanced in the process.

[0081] Exemplary embodiments of the present disclosure are further described below in conjunction with the accompanying drawings.

[0082] The text and drawings are provided as examples only to help understand the present disclosure. They should not be interpreted as limiting the scope of the present disclosure in any way. Although certain embodiments and examples have been provided, it will be apparent to those skilled in the art based on what is disclosed herein that the embodiments and examples shown may be changed without departing from the scope of the present disclosure.

[0083] Before introducing the specific content, some assumptions and definitions of the present disclosure are given below.

[0084] The message names in this disclosure are only examples, and other message names may also be used.

[0085] The “first”, “second”, etc. included in the message names in the present disclosure are just examples of messages and are only used to distinguish between messages, and do not represent the execution order.

[0086] Detailed descriptions of steps irrelevant to the present disclosure are omitted in the present disclosure.

[0087] In the present disclosure, the steps in various aspects, methods, and processes can be performed in combination with each other or individually. The execution steps of each process are only examples and do not exclude other possible execution orders.

[0088] In the present disclosure, the base station may be a 5G base station (such as gNB, ng-eNB), a 4G base station (such as eNB), a 6G base station, or other types of access nodes.

[0089] In the present disclosure, transmission of data refers to receiving and / or sending of data.

[0090] First aspect: Anchor node CU triggers DU migration

[0091] according to Figure 4a-4d In the present disclosure, the anchor node CU to which the mAB-MT and the mAB-DU are anchored may be represented by the following terms:

[0092] Source non-F1 terminating donor CU: the anchor node CU to which the mIAB-MT is anchored before migration; in this article, it may also be referred to as the fourth node;

[0093] Source F1 terminating donor CU: the anchor node CU to which the mIAB-DU is anchored before migration; in this article, it may also be referred to as the second node;

[0094] Target non-F1 terminating donor CU: the anchor CU to which the mIAB-MT is anchored after migration;

[0095] Target F1 terminating donor CU: mIAB-

[0096] The anchor node CU to which the DU is anchored after migration. In this article, it can also be called the third node.

[0097] The initial state of the anchor node CU anchored by mAB-MT and mAB-DU and the migration of mAB-MT and mAB-DU can be represented by the above four anchor node CUs. For example, if the initial state is that both mAB-MT and mAB-DU are anchored on the same anchor node CU, and only mAB-DU is migrated, then the source non-F1 termination anchor node CU and the source F1 termination anchor node CU are the same anchor node CU; because mAB-MT has not migrated, the target non-F1 termination anchor node CU is also the same anchor node CU as the source non-F1 termination anchor node CU; because only mAB-DU migration occurs, the target F1 termination anchor node CU is different from the source non-F1 termination anchor node CU, the source F1 termination anchor node CU, and the target non-F1 termination anchor node CU. So in this way, all different situations of the migration of mAB-MT and mAB-DU can be represented by the above four anchor node CUs.

[0098] Figure 5 The example flow chart of DU migration triggered by terminating anchor node CU for source F1. Because the present disclosure is mainly proposed for mAB-DU migration, mAB-MT migration is not the focus of the present disclosure. Figure 5 The target non-F1 termination anchor node CU is omitted. An example specific process is as follows:

[0099] 1) In step 501, the source F1 termination anchor node CU sends a first message to the mAB node to trigger the mAB node to initiate an F1 setup procedure or an F1 setup request (F1 setup procedure or F1 setup request) to the target F1 termination anchor node CU. For example, the first message may include information for triggering the mAB node to initiate an F1 setup procedure or an F1 setup request to the target F1 termination anchor node CU. The first message may be an F1 setup triggering message (F1 setup triggering message), or an F1 setup triggering signaling (F1 setup triggering signaling), etc., which is not limited here.

[0100] The first message may carry one or more of the following: a node identifier (e.g., a gNB ID, hereinafter, the node identifier may be referred to as a gNB ID) and / or an IP address of the target F1 termination anchor node CU, an mAB generated by the source non-F1 termination anchor node CU;

[0101] MT ID (i.e., MT UE XnAP ID) (e.g., mIAB-MT ID generated for the MT of the mIAB node) and / or gNBID may also carry the F1 traffic profile related to the mIAB node, or an indication that the mIAB node sends the F1 traffic profile to the target F1 termination anchor node CU, which may be an F1 traffic profile indication

[0102] (F1 traffic profile indication), or F1 traffic profile request (F1 traffic profile request), the message name is not limited here. The F1 traffic profile may include at least one of the following: the number of UEs served by the mAB node, the number of Data Radio Bearers (DRB) and / or traffic type (traffic type) of each UE, the radio resource status (Radio Resource Status), the activated cell list (activated cell list), etc. The F1 traffic profile can be at the cell level or at the UE level. When the target F1 termination anchor node CU knows the F1 traffic profile related to the mAB node, it helps it to perform admission control (admission control), that is, whether to approve the request for DU migration.

[0103] In step 502, after the mAB node receives the first message, the mAB-MT sends a second message to the source non-F1 termination anchor node CU. The second message may be an RRC message, and the RRC message may be IAB other information (IAB otherinformation) or other RRC messages, which are not limited here. When the mAB node knows that DU migration is to be performed, a second logical DU (i.e., mAB-DU2) is generated to initiate an F1 establishment process to the target F1 termination anchor node CU. The first logical DU (i.e., mAB-DU1) maintains an F1 connection with the source F1 termination anchor node CU, and mAB-DU1 and mAB-DU2 are on one mAB-DU entity.

[0104] The second message may carry or include at least one of the following: target F1 termination anchor

[0105] The gNB ID and / or IP address of the node CU, and / or the indication information that the mAB node is about to perform DU migration (i.e., DU migration indication (indication for DU migration)), the source non-F1 termination anchor node CU can know that the mAB node is about to perform DU migration, and which anchor node CU the target F1 termination anchor node CU is. At this time, the source non-F1 termination anchor node CU will not trigger the mAB-MT migration to avoid the simultaneous occurrence of mAB-MT migration and mAB-DU migration. In one example, the second message may not carry the indication information that the mAB node is about to perform DU migration. In this case, the indication information that the mAB node is about to perform DU migration can be implicitly indicated by the gNB ID and / or IP address of the target F1 termination anchor node CU. In one example, the second message may carry the indication information that the mAB node is about to perform DU migration. In this case, the indication information that the mAB node is about to perform DU migration can be explicitly indicated. When the TNL address (TNL address, Transport Network Layer address) of mAB-DU2 is configured by operation administration and maintenance (OAM), or when mAB-DU2 selects one from a TNL address set / list pre-configured by OAM or the source non-F1 termination anchor node CU, the second message also needs to carry the TNL address of mAB-DU2, so that the source non-F1 termination anchor node CU can configure the BAP configuration (BAP configuration, backhaul adaptation protocol configuration) for mAB-DU2 after knowing it.

[0106] In step 503, mAB-DU2 sends a third message to the target F1 termination anchor node CU to send an F1 connection establishment request to the target F1 termination anchor node CU, and the request may be an F1 setup request (or referred to as an F1 connection establishment request) or other F1AP messages, which are not limited here. For example, the third message may include an F1 connection establishment request with the target F1 termination anchor node CU.

[0107] The third message may carry or include at least one of the following: source non-F1 termination anchor

[0108] The mIAB-MT ID generated by the node CU and its gNB ID, the gNB ID of the source F1 termination anchor node CU, the F1 service profile related to the mIAB node, the activation cell list expected or wanted by mIAB-DU2, and the cell group configuration (CellGroupConfig) related information of mIAB-DU1, etc. After the target F1 termination anchor node CU knows the gNBID of the source F1 termination anchor node CU, it can know whether there is an Xn interface with it, so as to help the target F1 termination anchor node CU to perform admission control. After the target F1 termination anchor node CU knows the activation cell list expected or wanted by mIAB-DU2 and / or the F1 service profile related to the mIAB node, it can also help it to perform admission control. After the target F1 termination anchor node CU knows the CellGroupConfig related information of mIAB-DU1, it is convenient for it to configure the same CellGroupConfig for mIAB-DU2.

[0109] In step 504, after receiving the third message, the target F1 termination anchor node CU sends a fourth message to the mAB-DU2 to tell the mAB node whether it agrees to establish an F1 connection with it. The fourth message can be an F1 setup response (F1 setupresponse) or other F1AP messages, which are not limited here.

[0110] The fourth message may carry at least one of the following: whether to accept F1 establishment (e.g.

[0111] For example, the indication information of the above F1 connection establishment request), the activated cell list on the mIAB-DU2 (i.e., Cells to be Activated list), acceptable F1 services and / or F1 service profiles, and the mIAB-MT ID (i.e., MT UE XnAP ID) generated by the target F1 termination anchor node CU.

[0112] In step 505, after the mIAB node receives the fourth message, the mIAB-MT sends a fifth message (eg, an RRC message, such as an UL RRC message) to the source non-F1 terminating anchor node CU.

[0113] The fifth message may be an RRC message, and may carry the mIAB-MT ID generated by the target F1 termination anchor node CU (for example, the mIAB-MTID generated for the MT of the mIAB node). After the source non-F1 termination anchor node CU receives the fifth message, it is convenient for it to accept the IAB transport migration management (IAB Transport Migration Management, IAB TMM) message subsequently sent by the target F1 termination anchor node CU, because the IAB TMM message sent by the target F1 termination anchor node CU to the source non-F1 termination anchor node CU needs to include the mIAB-MT ID generated by the target F1 termination anchor node CU and the source non-F1 termination anchor node CU.

[0114] MT ID.

[0115] 6) In step 506, when the F1 connection between the mIAB-DU2 and the target F1 termination anchor node CU is successfully established, the mIAB-DU1 sends a sixth message (Indication for successful F1 setup) to the source F1 termination anchor node CU, so that the source F1 termination anchor node CU knows that the F1 connection between the mIAB-DU2 and the target F1 termination anchor node CU is successfully established.

[0116] The sixth message may be an F1AP message, which may carry, in addition to the indication information that the F1 connection between the mAB-DU2 and the target F1 termination anchor node CU is successfully established, at least one of the following: information related to the service cell activated on the mAB-DU2 (for example, a list of activated service cells, an activated service cell ID, and the ServCellInfo IE or part of the information in the IE, such as uplink or downlink carrier frequency, transmission bandwidth, etc.), the target cell ID, the F1 service acceptable to the target F1 termination anchor node CU and / or the F1 service profile, so that the source F1 termination anchor node CU may decide whether to replace the target F1 termination anchor node CU to which the mAB-DU is to migrate.

[0117] 7) In step 507, after the source F1 termination anchor node CU receives the sixth message, if it agrees to migrate the mAB-DU to the target F1 termination anchor node CU, that is, it can accept the F1 service and / or F1 service profile that the target F1 termination anchor node CU can accept, then the source F1 termination anchor node CU performs the UE context switching (HO) process.

[0118] Specifically, the source F1 terminates the anchor node CU to send a handover command to the UE, the handover command carries a target cell ID selected from the target cell IDs, the UE performs cell handover, and after the handover is completed, the UE sends an RRC reconfiguration completion message to the target cell.

[0119] In another embodiment, the source F1 terminates when the anchor node CU receives Figure 5 After receiving the sixth message in the, if the source F1 termination anchor node CU is not approved to migrate the mAB-DU to the target F1 termination anchor node CU, that is, the source F1 termination anchor node CU cannot accept the F1 service and / or F1 service profile that the target F1 termination anchor node CU can accept, then the source F1 termination anchor node CU can change the target F1 termination anchor node CU to which the mAB-DU is to migrate. The process is as follows: Figure 6 An example of the specific process is as follows:

[0120] 1) Figure 6 The first 6 steps in (i.e., F1 setup trigger, RRC message, F1 setup request, F1 setup response, RRC message, and F1 setup success) are the same as Figure 5 The first 6 steps are the same as in the previous section and will not be repeated here.

[0121] 2) In step 601, after the source F1 termination anchor node CU receives the sixth message sent by mIAB-DU1, if it does not agree with the migration of mIAB-DU to the target F1 termination anchor node CU, that is, it cannot accept the F1 service and / or F1 service profile that the target F1 termination anchor node CU can accept, then the source F1 termination anchor node CU sends a seventh message to mIAB-DU1, instructing the mIAB node to cancel (or remove) the newly established F1 connection between mIAB-DU2 and the target F1 termination anchor node CU.

[0122] The seventh message may be an F1AP message, which may reuse the first message but carry different message contents, or may be a newly defined message, which is not limited here. The seventh message may carry or include at least one of the following: cancel / remove mIAB-

[0123] The seventh message may also carry or include at least one of the following:

[0124] The mAB-MT ID (i.e., MT UE XnAPID) and / or gNB ID generated by the source non-F1 termination anchor node CU, as well as the F1 service profile related to the mAB node, and / or the indication information for the mAB node to send the F1 service profile to the new target F1 termination anchor node CU.

[0125] 3) In step 602, after the mIAB node receives the seventh message, the mIAB-DU2 sends an eighth message to the target F1 termination anchor node CU to instruct to cancel / remove the newly established F1 connection between the mIAB-DU2 and the target F1 termination anchor node CU.

[0126] ·The eighth message may be an F1AP message, an F1 removal request (F1 removalrequest) message, or other F1AP messages, which are not limited here. The eighth message may include information indicating the cancellation / removal of the newly established (i.e., the successfully established above) F1 connection between the mIAB-DU2 and the target F1 termination anchor node CU. The eighth message may also carry a new cause value (i.e., new cause value) to indicate the reason for the F1 removal to the target F1 termination anchor node CU. The meaning of this value may be that the source F1 termination anchor node CU does not agree to DU migration, or the source F1 termination anchor node CU cannot accept the F1 service and / or F1 service profile that the target F1 termination anchor node CU can accept.

[0127] 4) In step 603, after receiving the eighth message, the target F1 termination anchor node CU replies to the mIAB-DU2 with the ninth message, indicating that it agrees to proceed with the F1 removal process.

[0128] The ninth message may also be an F1AP message, an F1 removal response message, or other F1AP messages, which are not limited here. For example, the ninth message may include at least one of the following: information indicating that the target F1 termination anchor node CU agrees to cancel / remove the above-mentioned successfully established F1 connection between the mIAB-DU2 and the target F1 termination anchor node CU.

[0129] 5) After receiving the ninth message, mAB-DU2 indicates that the newly established F1 connection between mAB-DU2 and the target F1 termination anchor node CU has been canceled / removed. Then, according to the gNB ID and / or IP address of the new target F1 termination anchor node CU in the seventh message sent by the source F1 termination anchor node CU, the F1 establishment process (or F1 establishment request) is initiated to the new target F1 termination anchor node CU. The following process is the same as Figure 5 The third message in the process and the process after the third message are similar and will not be described repeatedly here.

[0130] Second aspect: OAM triggers mAB-DU migration When mAB-DU is triggered by OAM, it can be divided into three different situations, such as Figure 7 As shown: Case 1: When OAM decides to let the mAB node perform DU migration, it sends F1 to the mAB-DU

[0131] The trigger message is established to allow the mAB-DU to directly initiate the F1 establishment process to the target F1 termination anchor node CU.

[0132] Case 2: When OAM decides to let the mAB node perform DU migration, it first sends a

[0133] Send F1 establishment trigger message (and / or DU migration indication message); after receiving the message, the mAB node knows that OAM wants it to perform DU migration. However, the mAB node does not directly initiate the F1 establishment process to the target F1 termination anchor node CU, but first communicates with the source F1 termination anchor node CU. If the source F1 termination anchor node CU agrees, it will then send the F1 establishment process to the target F1 termination anchor node CU.

[0134] CU initiates the F1 establishment process.

[0135] Case 3: When OAM decides to let the mAB node perform DU migration, it first notifies the source F1 to terminate the anchor

[0136] The node CU, if the source F1 termination anchor node CU agrees to perform DU migration, sends an F1 establishment trigger message to the mAB node, triggering the mAB node to initiate an F1 establishment process to the target F1 termination anchor node CU.

[0137] Therefore, it is necessary to provide the process of OAM triggering mAB-DU migration according to the above three different situations.

[0138] Figure 8 This is a flowchart of case 3. Since DU migration is triggered by OAM, the target F1 termination anchor node CU to which the mAB-DU is to migrate is determined by OAM. An example specific process is as follows:

[0139] 1) In step 801, when OAM decides to trigger DU migration, OAM sends a tenth message to the source F1 terminating anchor node CU.

[0140] The tenth message may carry or include at least one of the following: indication information that the mIAB-DU migration is to be performed (eg, information indicating that the mIAB node is to perform DU migration), and

[0141] / or the gNB ID and / or IP address of the target F1 termination anchor node CU, so that the source F1 termination anchor node CU knows which anchor node CU the mAB-DU will be migrated to, and whether to agree to migrate the mAB-DU to the anchor node CU. The tenth message may also carry the mAB-DU ID and / or the mAB-MT ID generated by the source F1 termination anchor node CU, so that the source F1 termination anchor node CU knows which DU or which mAB node's DU needs to be migrated, because the source F1 termination anchor node CU may serve multiple mAB nodes.

[0142] 2) After the source F1 termination anchor node CU receives the tenth message sent by OAM, if it agrees to perform DU migration, it sends the first message, namely, F1 setup triggering message, to the mAB-DU to trigger the mAB node to initiate the F1 setup process to the target F1 termination anchor node CU. The following process is the same as Figure 5 The process is the same and will not be repeated here.

[0143] Fig. 9 This is a flowchart of situation 2. The specific process of an example is as follows:

[0144] 1) In step 901, when OAM decides to trigger DU migration, OAM sends an eleventh message to the mAB node, and the message may include information for instructing the mAB node to perform DU migration.

[0145] The eleventh message may carry or include at least one of the following: the gNBID and / or IP address of the target F1 termination anchor node CU, so that the mAB node knows which target anchor node CU the DU needs to migrate to.

[0146] 2) In step 902, after receiving the eleventh message sent by OAM, the mAB node sends a twelfth message to the source F1 termination anchor node CU, which may include information indicating that the source F1 termination anchor node CU is to perform mAB-DU migration. The twelfth message may be an F1AP message or other appropriate message.

[0147] The twelfth message may carry or include at least one of the following: the gNBID and / or IP address of the target F1 termination anchor node CU, so that the source F1 termination anchor node CU knows to which target anchor node CU the mAB-DU is migrated.

[0148] 3) If the source F1 termination anchor node CU agrees to the migration of the mAB-DU (i.e., agrees to migrate the mAB-DU to the target F1 termination anchor node CU), the source F1 termination anchor node CU sends a first message to the mAB node to trigger the mAB node to initiate the F1 establishment process to the target F1 termination anchor node CU. The following process is as follows Figure 5 The description is described in , and will not be repeated here.

[0149] The first message here may no longer contain the gNBID and / or IP address of the target F1 termination anchor node CU, because the mAB node has already obtained this information from OAM.

[0150] Fig.10 This is a flow chart of case 1. Because OAM directly triggers the mAB node to perform DU migration, the source F1 termination anchor node CU does not know which target anchor node CU the mAB-DU has migrated to until the F1 connection between the mAB-DU2 and the target F1 termination anchor node CU is successfully established. Therefore, the process of case 1 is quite different from that of cases 2 and 3. An example of the specific process is as follows:

[0151] 1) In step 1001, when OAM decides to trigger DU migration, OAM sends an eleventh message to the mLAB node, and the message may include information for instructing the mLAB node to perform DU migration.

[0152] The eleventh message may carry or include at least one of the following: the gNBID and / or IP address of the target F1 termination anchor node CU, so that the mAB node knows which target anchor node CU the DU needs to migrate to. It may also carry the TNL address configured by OAM for mAB-DU2.

[0153] 2) In step 1002, after receiving the eleventh message sent by OAM, the mAB node knows that OAM requires it to perform DU migration, and then generates a second logical DU, namely, mAB-DU2.

[0154] The MT sends a second message to the source non-F1 terminating anchor node CU.

[0155] The content contained in the second message can be Figure 5 Same as the second message in .

[0156] 3) After receiving the second message, the source non-F1 termination anchor node CU knows that the mAB-DU is to be migrated, and the source non-F1 termination anchor node CU no longer triggers MT migration to avoid simultaneous migration of MT and DU. In step 1003, after receiving the second message, the source non-F1 termination anchor node CU sends a thirteenth message to the mAB-MT, so that the mAB node tells the target F1 termination anchor node CU the generated mAB-MT ID.

[0157] The thirteenth message may be an RRC message (eg, a DL RRC message), and may carry or include at least one of the following: an mIAB-MT ID generated by the source non-F1 termination anchor node CU (eg, an mIAB-MTID generated for the MT of the mIAB node);

[0158] and / or its gNB ID.

[0159] 4) In step 1004, after the mIAB node receives the thirteenth message, the mIAB-DU2 sends a third message to the target F1 termination anchor node CU. The content contained in the third message can be the same as Figure 5 Same as the third message.

[0160] 5) In step 1005, after receiving the third message, the target F1 terminating anchor node CU sends a

[0161] DU2 replies with a fourth message, the content of which may be Figure 5 Same as in the fourth message.

[0162] 6) In step 1006, after receiving the fourth message, the mAB node sends a fifth message to the source non-F1 termination anchor node CU. The content contained in the fifth message can be the same as Figure 5 Same as the fifth message.

[0163] 7) In step 1007, the mIAB-DU1 sends a sixth message to the source F1 termination anchor node CU, notifying it that the F1 connection between the mIAB-DU2 and the target F1 termination anchor node CU is successfully established.

[0164] The sixth message contains Figure 5 In addition to the same content as the sixth message in the UE context switching message, the gNB ID and / or IP address of the target F1 termination anchor node CU must also be carried, so that the source F1 termination anchor node CU knows which target anchor node CU the mAB-DU has been migrated to, and the source F1 termination anchor node CU decides whether to agree to migrate the DU to the target F1 termination anchor node CU. If the source F1 termination anchor node CU agrees to the DU migration, the UE context switching process can be performed; if the source F1 termination anchor node CU does not agree to the DU migration, the UE context switching process can be performed. Figure 6 The process in .

[0165] In some embodiments, whether the DU migration is triggered by the anchor node CU in the first aspect or by the OAM in the second aspect, the mAB-DU2 needs to tell the target F1 termination anchor node CU the list of service cells that it wants or expects to activate, so that the target F1 termination anchor node CU can perform admission control. For example, the mAB node or the mAB-DU2 can send information about the list of service cells that the mAB node or the mAB-DU2 expects to activate to the target F1 termination anchor node CU. One aspect of the present disclosure also proposes the following methods for signaling enhancement in the F1 establishment request:

[0166] Option 1: directly add a new information element (IE) (referred to as the first IE in this article) in the F1 establishment request to directly indicate the list of serving cells that the mIAB-DU2 wants or expects to activate. The IE may be called a preference for activated cells list or other names, which are not limited here. Fig.11 An example of this IE is shown.

[0167] Option 2: Add status information after the served cell list, such as preference status, that is, each served cell ID corresponds to a preference status. The preference status can be "preferred" or "not preferred"; it can also be "true (indicating desired / expected)" or "false (indicating unwanted / unexpected)"; it can also be that when the served cell ID has a corresponding preference status, it means it is desired / expected, and when it does not, it means it is unwanted / unexpected.

[0168] Option 3: Add a new IE (referred to as the second IE in this article) in the F1 establishment request, which indicates that the cells in the serving cell list are the serving cell list that the mAB node wants or expects to activate. The IE can be called preference for all served cells or other names, which are not limited here. An example of the IE is as follows: Fig.11In one embodiment, if the IE exists, it indicates that the cells in the service cell list are all service cell lists that the mIAB node wants or expects to activate; if it does not exist, there is no such indication. In another embodiment, it can also be indicated by 1 bit, and when the bit is 1, it indicates that the cells in the service cell list are all service cell lists that the mIAB node wants or expects to activate; when it is 0, there is no such indication, and vice versa.

[0169] Aspect 3: Notification of successful establishment of a new F1 connection when source link loss occurs

[0170] Due to the mobility of the mAB node, before the migration of the mAB-DU is completed, the mAB-DU1 may lose (or disconnect) the F1 connection with the source F1 termination anchor node CU. This problem is called source link loss. There are many reasons for the source link loss, such as a parent IAB node (parentIAB node) between the source F1 termination anchor node CU and the mAB-DU1 being disconnected from the source F1 termination anchor node CU or the mAB-DU1. However, when the F1 connection between the mAB-DU2 and the target F1 termination anchor node CU is successfully established, the mAB node needs to notify the source F1 termination anchor node CU. If the source link loss occurs, it cannot be notified to the source F1 termination anchor node CU through the mAB-DU1, so the present disclosure proposes a corresponding solution to this problem. The specific process is as follows: Fig.12 As shown, an example specific process is as follows:

[0171] 1) When the source link loss occurs, the mAB-DU1 cannot send the sixth message (eg, successful F1 setup) to the source F1 termination anchor node CU, and the mAB node will know that the source link loss occurs.

[0172] 2) In step 1201, mIAB-DU2 sends a fourteenth message to the target F1 termination anchor node CU, which is used to indicate that the target F1 termination anchor node CU source F1 connection is disconnected (ie, the F1 connection between mIAB-DU1 and the source F1 termination anchor node CU is disconnected).

[0173] The fourteenth message may be an F1AP message, which may reuse the third message or be a new message. In addition to instructing the target F1 termination anchor node CU that the source F1 connection is disconnected, the target F1 termination anchor node CU may also be instructed to send the content of the sixth message originally sent by mIAB-DU1 to the source F1 termination anchor node CU to the source F1 termination anchor node CU. The message may also carry the content of the sixth message, and optionally, may not carry the content of the sixth message known to the target F1 termination anchor node CU. The message may also carry indication information, instructing the target F1 termination anchor node CU to notify the source F1 termination anchor node CU of the source link loss.

[0174] 3) In step 1202, after receiving the fourteenth message, the target F1 termination anchor node CU sends the fifteenth message to the source F1 termination anchor node CU, so that the source F1 termination anchor node CU knows that the F1 connection between the mIAB-DU2 and the target F1 termination anchor node CU is successfully established.

[0175] The fifteenth message may be XnAP (Xn Application Protocol)

[0176] The message may be an Xn setup request message or other XnAP message, which is not limited here. In addition to the indication information that the F1 connection is successfully established, the message may also include an indication of the source link loss, and Figure 5 For example, the fifteenth message may include at least one of the following: information indicating that the F1 connection between the mIAB-DU2 and the target F1 termination anchor node CU is successfully established, information indicating that the source F1 connection between the mIAB-DU1 and the source F1 termination anchor node CU is disconnected, Figure 5 One or more of the contents carried by the sixth message.

[0177] 4) In step 1203, after receiving the fifteenth message, the source F1 terminating anchor node CU knows that the source link is lost. In the event of the source link being lost, the UE context switching process is performed.

[0178] This embodiment solves the problem of how to notify the source F1 termination anchor node CU that a new F1 connection is successfully established when the source link is lost.

[0179] Aspect 4: Avoid simultaneous migration of MT and DU

[0180] The present invention mentioned earlier that when the source F1 termination anchor node CU triggers the mAB node to perform DU migration, the mAB node will send a second message to the source non-F1 termination anchor node CU. At this time, the source non-F1 termination anchor node CU will not trigger the migration of MT after receiving the second message and knowing the DU migration. In another case, MT migration may occur before DU migration. At this time, it is also necessary to let the source F1 termination anchor node CU know the MT migration so as not to continue to trigger the migration of DU. The specific process is as follows:

[0181] 1) The source F1 termination anchor node CU sends a first message to the mAB node (or mAB-DU1) to trigger the mAB node to initiate an F1 setup procedure or F1 setup request (F1 setup procedure or F1 setup request) to the target F1 termination anchor node CU. Figure 5 Step 501.

[0182] 2) The mIAB node knows that it is performing MT migration, and after receiving the first message sent by the source F1 termination anchor node CU, it replies with the sixteenth message to the source F1 termination anchor node CU.

[0183] The message is an F1AP message, which can be an F1 setup failure message or other F1AP messages, which are not limited here. If the message is an F1 setup failure message, it can carry a new cause value, which indicates the reason why the source F1 terminates the anchor node CU and its F1 setup fails, which can be that MT migration is in progress / will be carried out. If the message is other F1AP messages or a newly defined F1AP message, it can carry indication information, which indicates that MT is in progress / will be migrated.

[0184] 3) After receiving the sixteenth message, the source F1 termination anchor node CU no longer triggers the mIAB node to perform DU migration during the MT migration process.

[0185] In another embodiment, when the mAB node performs MT migration, it can also actively send indication information to the source F1 termination anchor node to indicate that it is performing MT migration. The specific process is as follows:

[0186] 1) The source non-F1 termination anchor node CU sends the seventeenth message to the mAB node (or mAB-MT), which is used to trigger the mAB node to perform MT migration.

[0187] The message is an RRC message, which may be an RRC reconfiguration message or other RRC messages, which is not limited here.

[0188] 2) After receiving the seventeenth message, the mAB node knows that the MT migration is to be performed, and then sends the eighteenth message to the source F1 termination anchor node CU, indicating that it is performing / will perform the MT migration.

[0189] The eighteenth message is an F1AP message. The eighteenth message may reuse the sixteenth message, or may be other F1AP messages, which is not limited here.

[0190] 3) After receiving the eighteenth message, the source F1 termination anchor node CU no longer triggers the mAB node to perform DU migration during the MT migration process.

[0191] In another embodiment, when the source non-F1 termination anchor node CU decides to perform MT migration, it can directly inform the source F1 termination anchor node CU. At this time, the source F1 termination anchor node CU no longer triggers the mAB node to perform DU migration during the MT migration process. The flow chart is as follows Fig.13 As shown, the specific steps of an example are as follows:

[0192] 1) In step 1301, when the source non-F1 termination anchor node CU decides to perform MT migration, it sends the twenty-fifth message to the source F1 termination anchor node CU, indicating that the source F1 termination anchor node CU is about to migrate / is currently migrating its mIAB-MT.

[0193] The message may be an XnAP message. In addition to the above-mentioned indication information, it may also carry the gNB ID and / or IP address of the target non-F1 termination anchor node CU, so as to let the source F1 termination anchor node CU know to which target IAB anchor node the mIAB-MT is migrated; it may also carry a timer, which is used by the source non-F1 termination anchor node CU to determine whether feedback from the source F1 termination anchor node CU is received within the timer.

[0194] 2) In step 1302, after the source F1 termination anchor node CU receives the twenty-fifth message and knows the target IAB anchor node to which the mAB-MT will be migrated, it determines whether to migrate the mAB-DU. If the source F1 termination anchor node CU decides to migrate the DU and also migrates the mAB-DU to the target non-F1 termination anchor node CU, the twenty-sixth message is sent to the source non-F1 termination anchor node CU within the timer, indicating that its mAB-DU is also to be migrated to the target non-F1 termination anchor node CU. On the contrary, if it does not decide to migrate the DU or does not migrate the mAB-DU to the target non-F1 termination anchor node CU, the twenty-sixth message is not sent. The twenty-sixth message is an XnAP message.

[0195] 3) In step 1303, if the source non-F1 termination anchor node CU receives the twenty-sixth message, the twenty-seventh message sent to the target non-F1 termination anchor node CU carries part or all of the UE context information, or all or part of the context information of a part of the UE. On the contrary, if the twenty-sixth message is not received, the twenty-seventh message sent to the target non-F1 termination anchor node CU does not carry the relevant information of the UE context. The twenty-seventh message is an XnAP message, which can be a handover request message or other messages, which are not limited here.

[0196] Fifth aspect: Network integration process of mAB nodes

[0197] During the network integration process, mIAB-MT and mIAB-DU can also be connected to different IAB anchor nodes respectively. The flow chart is as follows: Fig.14 As shown, the specific process is as follows:

[0198] 1) In step 1401, the mAB-MT initiates a random access process to the source non-F1 termination anchor node CU to complete the mAB-MT integration process;

[0199] 2) In step 1402, OAM configures DU-related parameters for the mAB-DU, and allocates the source F1 termination anchor node CU to the mAB-DU, that is, OAM sends the gNB ID and / or IP address of the source F1 termination anchor node CU to the mAB-DU;

[0200] 3) In step 1403, after the mAB-DU knows the gNB ID and / or IP address of the source F1 termination anchor node CU, the mAB-MT sends the nineteenth message to the source non-F1 termination anchor node CU to inform the source non-F1 termination anchor node CU of the relevant information of the source F1 termination anchor node CU;

[0201] The nineteenth message is an RRC message, which can be multiplexed with the second message or other RRC messages, which is not limited here. The message can carry the gNB ID and / or IP address of the source F1 terminating anchor node CU, and the ID and / or IP address of the mAB-DU;

[0202] 4) In step 1404, after receiving the nineteenth message, the source non-F1 terminating anchor node CU replies to the mIAB-MT with a twentieth message, which carries BAP configuration related information.

[0203] The twentieth message is an RRC message, which may be an RRC reconfiguration message or other messages, which are not limited here. In addition to carrying BAP-related configuration messages, it may also carry the mAB-MT ID generated by the source non-F1 termination anchor node CU (for example, the mAB-MT ID generated for the MT of the mAB node) and / or its gNB ID. Optionally, if the mAB node is triggered by the source non-F1 termination anchor node CU to perform an F1 setup procedure (F1 setup procedure) during the network integration process, it is also necessary to carry information for triggering the mAB node to initiate an F1 setup procedure or an F1 setup request to the source F1 termination anchor node CU. If the mAB node is triggered by OAM to perform the F1 setup procedure during the network integration process, the trigger information does not need to be carried.

[0204] 5) In step 1405, after receiving the 20th message, the mAB node sends a 21st message to the source F1 termination anchor node CU to initiate the F1 establishment process.

[0205] The twenty-first message is an F1AP message, which may reuse the third message or be a new message, which is not limited here. The message may carry the mAB-MT ID generated by the source non-F1 termination anchor node CU (for example, the mAB-MT ID generated for the MT of the mAB node) and / or its gNB ID.

[0206] 6) In step 1406, the source F1 termination anchor node CU replies to the mAB-DU with a 22nd message to tell the mAB node whether it agrees to establish an F1 connection with it. The 22nd message can be an F1 setup response, can reuse the fourth message, or can be another F1AP message, which is not limited here. The message content carried is the same as the fourth message.

[0207] 7) In step 1407, the source F1 termination anchor node CU sends a twenty-third message to the source non-F1 termination anchor node CU to trigger the IAB TMM process.

[0208] The twenty-third message is an XnAP message, which can be an IAB TMM request (IAB TMM request) or other XnAP messages, which are not limited here. The message can also carry an indication of successful F1 establishment, indicating that the F1 connection between the source non-F1 termination anchor node CU and its mIAB-DU and the source F1 termination anchor node CU is successfully established. If the twenty-third message does not carry the indication of successful F1 establishment, the mIAB-MT needs to send an RRC message to the source non-F1 termination anchor node CU to indicate that the F1 connection between the source non-F1 termination anchor node CU and its mIAB-DU and the source F1 termination anchor node CU is successfully established.

[0209] 8) In step 1408, after receiving the 23rd message, the source non-F1 termination anchor node CU replies with a 24th message to the source F1 termination anchor node CU. The message is an XnAP message, which may be an IAB TMM response (IAB TMM response) or other XnAP messages, which are not limited here.

[0210] It should be understood that, depending on the application scenario, the various exemplary aspects, methods, steps, processes, etc. shown in the above-mentioned drawings can be combined and implemented in any manner, and this document does not limit this.

[0211] Next, Fig.15 A flowchart of a method 1500 performed by a first node in a wireless communication system according to an embodiment of the present disclosure is shown.

[0212] like Fig.15 As shown, according to an embodiment of the present disclosure, method 1500 performed by a first node in a wireless communication system may include: in step S1501, sending a third message to a third node, wherein the third message includes information about a list of service cells that the first node expects to activate and an F1 service profile; in step S1502, receiving a fourth message in response to the third message from the third node, wherein the fourth message includes an acceptable F1 service profile and information about cells to be activated; and in step S1503, sending a sixth message to the second node, wherein the sixth message includes information about the activated cells and an acceptable F1 service profile.

[0213] According to an embodiment of the present disclosure, the method 1500 may further include: receiving a first message from the second node, wherein the first message includes an F1 service profile.

[0214] According to an embodiment of the present disclosure, method 1500 may also include: sending a second message to a fourth node, wherein the second message includes at least one of the following: a transmission network layer TNL address of the second DU of the first node, a node identifier and / or IP address of the third node, and information indicating that the first node is about to perform a distribution unit DU migration.

[0215] According to an embodiment of the present disclosure, the method 1500 may further include: sending a fifth message to a fourth node, wherein the fifth message includes a mobile integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the third node for the first node.

[0216] According to an embodiment of the present disclosure, method 1500 may further include: receiving a seventh message from the second node, wherein the seventh message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a node identifier and / or IP address of the new target F1 termination anchor node CU; sending an eighth message to the third node, wherein the eighth message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a reason value for cancelling the successfully established F1 connection between the first node and the third node; and receiving a ninth message from the third node, wherein the ninth message includes information indicating that the third node agrees to cancel the successfully established F1 connection between the first node and the third node.

[0217] According to an embodiment of the present disclosure, the first message is sent from the second node when the second node receives the tenth message from the operation administration and maintenance OAM node, wherein the tenth message includes at least one of the following: information indicating that the first node performs distribution unit DU migration, the node identifier and / or IP address of the third node.

[0218] According to an embodiment of the present disclosure, method 1500 may also include: receiving an eleventh message from an operation administration and maintenance OAM node, wherein the eleventh message includes at least one of the following: information indicating that the first node performs distribution unit DU migration, a node identifier and / or an IP address of the third node; and sending a twelfth message to the second node, wherein the twelfth message includes the node identifier and / or the IP address of the third node.

[0219] According to an embodiment of the present disclosure, the first message is sent from the second node when the second node agrees that the distributed unit DU of the first node is migrated to the third node.

[0220] According to an embodiment of the present disclosure, method 1500 may also include: receiving an eleventh message from an operation administration and maintenance OAM node, wherein the eleventh message includes at least one of the following: information indicating that the first node performs distribution unit DU migration, the node identifier and / or IP address of the third node; receiving a thirteenth message from the fourth node, wherein the thirteenth message includes at least one of the following: a removable integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the fourth node for the first node, and a node identifier of the fourth node; and sending a fifth message to the fourth node, wherein the fifth message includes the removable integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the third node for the first node.

[0221] According to an embodiment of the present disclosure, the information about the list of service cells that the first node expects to activate is indicated by one or more of the following methods: indicated by a first information element in an F1 establishment request, wherein the first information element indicates a list of service cells that the first node expects to activate; indicated by status information corresponding to each service cell in the service cell list; or indicated by a second information element in the F1 establishment request, wherein the second information element indicates whether the cells in the service cell list are all service cells that the first node expects to activate.

[0222] According to an embodiment of the present disclosure, method 1500 may also include: in case the sending of the sixth message fails, sending a fourteenth message to the third node, wherein the fourteenth message includes at least one of the following: information for indicating that the source F1 connection between the first node and the second node is disconnected, information indicating that the third node sends the sixth message to the second node, and information indicating that the third node notifies the second node that the source F1 connection between the first node and the second node is disconnected.

[0223] Fig.16 A flowchart of a method 1600 performed by a second node in a wireless communication system according to an embodiment of the present disclosure is shown.

[0224] like Fig.16 As shown, according to an embodiment of the present disclosure, method 1600 performed by a second node in a wireless communication system may include: in step S1601, sending a first message to a first node, wherein the first message includes an F1 service profile; and in step S1602, receiving a sixth message from the first node, wherein the sixth message includes information of an activated cell and an acceptable F1 service profile.

[0225] According to an embodiment of the present disclosure, the method further includes: in a case where the distributed unit DU of the first node is allowed to migrate to the third node, executing a user equipment context switching process.

[0226] According to an embodiment of the present disclosure, method 1600 may further include: sending a seventh message to the first node, wherein the seventh message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a node identifier and / or IP address of the new target F1 termination anchor node CU.

[0227] According to an embodiment of the present disclosure, method 1600 may also include: receiving a tenth message from an operation administration and maintenance OAM node, wherein the tenth message includes at least one of the following: information instructing the first node to perform distribution unit DU migration, a node identifier and / or IP address of a third node, wherein the first message is sent to the first node when the second node receives the tenth message.

[0228] According to an embodiment of the present disclosure, method 1600 may also include: receiving a twelfth message from the first node, wherein the twelfth message includes a node identifier and / or IP address of a third node, wherein the node identifier and / or IP address of the third node is received by the first node from the operation administration and maintenance OAM node.

[0229] According to an embodiment of the present disclosure, the first message is sent from the second node when the second node agrees that the distributed unit DU of the first node is migrated to the third node.

[0230] According to an embodiment of the present disclosure, method 1600 may further include: in case of failure to receive the sixth message from the first node, receiving a fifteenth message from the third node, wherein the fifteenth message includes at least one of the following: information indicating that the F1 connection between the first node and the third node is successfully established, information indicating that the source F1 connection between the first node and the second node is disconnected, a target cell identifier, information on activated cells, and an acceptable F1 service profile.

[0231] Fig.17 A flowchart of a method 1700 performed by a third node in a wireless communication system according to an embodiment of the present disclosure is shown.

[0232] like Fig.17As shown, according to an embodiment of the present disclosure, method 1700 performed by a third node in a wireless communication system may include: in step S1701, receiving a third message from a first node, wherein the third message includes information about a list of service cells that the first node expects to activate and an F1 service profile; and in step S1702, sending a fourth message to the first node, wherein the fourth message includes an acceptable F1 service profile and information about cells to be activated.

[0233] According to an embodiment of the present disclosure, method 1700 may further include: receiving an eighth message from the first node, wherein the eighth message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a reason value for cancelling the successfully established F1 connection between the first node and the third node; and sending a ninth message to the first node, wherein the ninth message includes information indicating that the third node agrees to cancel the successfully established F1 connection between the first node and the third node, wherein the eighth message is sent from the first node when the first node receives the seventh message from the second node, wherein the seventh message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a node identifier and / or IP address of the new target F1 termination anchor node CU.

[0234] According to an embodiment of the present disclosure, the information about the list of service cells that the first node expects to activate is indicated by one or more of the following methods: indicated by a first information element in an F1 establishment request, wherein the first information element indicates a list of service cells that the first node expects to activate; indicated by status information corresponding to each service cell in the service cell list; or indicated by a second information element in the F1 establishment request, wherein the second information element indicates whether the cells in the service cell list are all service cells that the first node expects to activate.

[0235] According to an embodiment of the present disclosure, method 1700 may also include: receiving a fourteenth message from the first node, wherein the fourteenth message includes at least one of the following: information indicating that the source F1 connection between the first node and the second node is disconnected, information indicating that the third node sends a sixth message to the second node, and information indicating that the third node notifies the second node that the source F1 connection between the first node and the second node is disconnected, wherein the fourteenth message is sent from the first node when the first node fails to send the sixth message to the second node.

[0236] According to an embodiment of the present disclosure, method 1700 may further include: sending a fifteenth message to the second node, wherein the fifteenth message includes at least one of the following: information indicating that the F1 connection between the first node and the third node is successfully established, information indicating that the source F1 connection between the first node and the second node is disconnected, a target cell identifier, information on activated cells, and an acceptable F1 service profile.

[0237] Fig.18 A flowchart of a method 1800 performed by a fourth node in a wireless communication system according to an embodiment of the present disclosure is shown.

[0238] like Fig.18 As shown, according to the embodiment of the present disclosure, the method 1800 executed by the fourth node in the wireless communication system may include: in step S1801, receiving a second message from the first node, wherein the second message includes at least one of the following: a transmission network layer TNL address of the second distribution unit DU of the first node, a node identifier and / or IP address of the third node, and information indicating that the first node is about to perform distribution unit DU migration; and in step S1802, receiving a fifth message from the first node, wherein the fifth message includes a mobile integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the third node for the first node.

[0239] According to an embodiment of the present disclosure, method 1800 may also include: sending a thirteenth message to the first node, wherein the thirteenth message includes at least one of the following: a mobile integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the fourth node for the first node, and a node identifier of the fourth node.

[0240] It should be understood that methods 1500, 1600, 1700 and 1800 according to the embodiments of the present disclosure may also include one or more of the methods or steps described above in combination with any examples, aspects or figures, which will not be repeated here.

[0241] Next, Fig.19 A schematic diagram of a node 1900 in a wireless communication system according to an embodiment of the present disclosure is shown.

[0242] like Fig.19As shown, the node 1900 according to an embodiment of the present disclosure (for example, it can be the first node as described above (for example, mIAB node or mIAB-MT or mIAB-DU, etc.), the second node (for example, the source F1 termination anchor node CU), the third node (for example, the target F1 termination anchor node CU) or any other network node) may include a transceiver 1910 and a processor 1920. The transceiver 1910 can be configured to send and receive signals. The processor 1920 can be coupled to the transceiver 1910 and can be configured (for example, to control the transceiver 1910) to execute any method performed by the first node and / or the second node and / or the third node and / or the fourth node in the wireless communication system according to an embodiment of the present disclosure.

[0243] In this article, a node may also be referred to as a node device. In this article, a processor may also be referred to as a controller.

[0244] Various embodiments of the present disclosure may be implemented as computer-readable codes embodied on a computer-readable recording medium from a specific perspective. A computer-readable recording medium is any data storage device that can store data readable by a computer system. Examples of computer-readable recording media may include read-only memory (ROM), random access memory (RAM), compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, optical data storage device, carrier wave (e.g., data transmission via the Internet), and the like. Computer-readable recording media may be distributed via a computer system connected via a network, and therefore computer-readable codes may be stored and executed in a distributed manner. Moreover, the functional programs, codes, and code segments for implementing the various embodiments of the present disclosure may be easily interpreted by a technician in the field of the embodiments of the present disclosure.

[0245] It will be understood that the embodiments of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software. Software may be stored as program instructions or computer-readable codes executable on a processor on a non-transient computer-readable medium. Examples of non-transient computer-readable recording media include magnetic storage media (e.g., ROM, floppy disk, hard disk, etc.) and optical recording media (e.g., CD-ROM, digital video disk (DVD), etc.). Non-transient computer-readable recording media may also be distributed on network-coupled computer systems so that computer-readable codes are stored and executed in a distributed manner. The medium may be read by a computer, stored in a memory, and executed by a processor. Various embodiments may be implemented by a computer or a portable terminal including a controller and a memory, and the memory may be an example of a non-transient computer-readable recording medium suitable for storing (multiple) programs having instructions for implementing embodiments of the present disclosure. The present disclosure may be implemented by a program having a code for specifically implementing the apparatus and method described in the claims, the program being stored in a machine (or computer) readable storage medium. The program may be electronically carried on any medium, such as a communication signal transmitted via a wired or wireless connection, and the present disclosure suitably includes its equivalents.

[0246] The above description is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can make various changes or substitutions within the technical scope disclosed in the present disclosure, and these changes or substitutions should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A method performed by a first node in a wireless communication system, comprising: Sending a third message to a third node, wherein the third message includes information about a list of serving cells that the first node desires to activate and an F1 service profile; receiving a fourth message in response to the third message from the third node, wherein the fourth message includes information of an acceptable F1 service profile and a cell to be activated; and A sixth message is sent to the second node, wherein the sixth message includes information of the activated cell and an acceptable F1 service profile.

2. The method according to claim 1, further comprising: A first message is received from a second node, wherein the first message includes an F1 service profile.

3. The method according to claim 1, further comprising: A second message is sent to the fourth node, wherein the second message includes at least one of the following: a transport network layer TNL address of a second DU of the first node, a node identifier and / or IP address of the third node, and information indicating that the first node is about to perform a distribution unit DU migration.

4. The method according to claim 1, further comprising: A fifth message is sent to the fourth node, wherein the fifth message includes a mobile integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the third node for the first node.

5. The method according to claim 1, further comprising: receiving a seventh message from the second node, wherein the seventh message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, a node identifier and / or an IP address of a new target F1 termination anchor node CU; sending an eighth message to the third node, wherein the eighth message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a reason value indicating cancellation of the successfully established F1 connection between the first node and the third node; and A ninth message is received from the third node, wherein the ninth message includes information indicating that the third node agrees to cancel the successfully established F1 connection between the first node and the third node.

6. The method according to claim 1, wherein: The first message is sent from the second node when the second node receives a tenth message from an operations administration and maintenance (OAM) node, The tenth message includes at least one of the following: information instructing the first node to perform distribution unit DU migration, and a node identifier and / or IP address of the third node.

7. The method according to claim 1, further comprising: receiving an eleventh message from an operation administration and maintenance (OAM) node, wherein the eleventh message includes at least one of the following: information indicating that the first node performs a distribution unit (DU) migration, a node identifier and / or an IP address of the third node; and A twelfth message is sent to the second node, wherein the twelfth message includes a node identifier and / or an IP address of the third node.

8. The method according to claim 7, wherein: The first message is sent from the second node when the second node agrees that the distributed unit DU of the first node is migrated to the third node.

9. The method according to claim 3, further comprising: receiving an eleventh message from an operation administration and maintenance OAM node, wherein the eleventh message includes at least one of the following: information indicating that the first node performs a distribution unit DU migration, a node identifier and / or an IP address of the third node; receiving a thirteenth message from the fourth node, wherein the thirteenth message includes at least one of the following: a mobile integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the fourth node for the first node, and a node identifier of the fourth node; and A fifth message is sent to the fourth node, wherein the fifth message includes a mobile integrated access and backhaul-mobile terminal mIAB-MT identifier generated by the third node for the first node.

10. The method according to claim 1, wherein: The information about the list of serving cells that the first node expects to activate is indicated in one or more of the following ways: Indicated by a first information element in the F1 establishment request, wherein the first information element indicates a list of serving cells that the first node desires to activate; Indicated by the status information corresponding to each serving cell in the serving cell list; or The second information element in the F1 establishment request is used to indicate whether the cells in the serving cell list are all serving cells that the first node desires to activate.

11. The method according to claim 1, further comprising: In case the sending of the sixth message fails, a fourteenth message is sent to the third node, wherein the fourteenth message includes at least one of the following: information for indicating that the source F1 connection between the first node and the second node is disconnected, information for indicating that the third node sends the sixth message to the second node, and information for indicating that the third node notifies the second node that the source F1 connection between the first node and the second node is disconnected.

12. A method performed by a second node in a wireless communication system, comprising: Sending a first message to the first node, wherein the first message includes an F1 service profile; and A sixth message is received from the first node, wherein the sixth message includes information of activated cells and an acceptable F1 service profile.

13. The method according to claim 12, further comprising: In the case of agreeing to migrate the distributed unit DU of the first node to the third node, a user equipment context switching process is performed.

14. The method according to claim 12, further comprising: A seventh message is sent to the first node, wherein the seventh message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a node identifier and / or IP address of a new target F1 termination anchor node CU.

15. The method according to claim 12, further comprising: receiving a tenth message from an operation administration and maintenance OAM node, wherein the tenth message includes at least one of the following: information indicating that the first node performs a distribution unit DU migration, a node identifier and / or an IP address of a third node, The first message is sent to the first node when the second node receives the tenth message.

16. The method according to claim 12, further comprising: receiving a twelfth message from the first node, wherein the twelfth message includes a node identifier and / or an IP address of a third node, The node identifier and / or IP address of the third node is received by the first node from an operation, administration and maintenance (OAM) node.

17. The method according to claim 16, wherein: The first message is sent from the second node when the second node agrees that the distributed unit DU of the first node is migrated to the third node.

18. The method according to claim 12, further comprising: In case of failure to receive the sixth message from the first node, a fifteenth message is received from the third node, wherein the fifteenth message includes at least one of the following: information indicating that the F1 connection between the first node and the third node is successfully established, information indicating that the source F1 connection between the first node and the second node is disconnected, a target cell identifier, information of an activated cell, and an acceptable F1 service profile.

19. A method performed by a third node in a wireless communication system, comprising: receiving a third message from the first node, wherein the third message includes information about a serving cell list that the first node desires to activate and an F1 service profile; and A fourth message is sent to the first node, wherein the fourth message includes information about an acceptable F1 service profile and a cell to be activated.

20. The method according to claim 19, further comprising: receiving an eighth message from the first node, wherein the eighth message includes at least one of: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and a cause value indicating cancellation of the successfully established F1 connection between the first node and the third node; and sending a ninth message to the first node, wherein the ninth message includes information indicating that the third node agrees to cancel the successfully established F1 connection between the first node and the third node, The eighth message is sent from the first node when the first node receives the seventh message from the second node, wherein the seventh message includes at least one of the following: information indicating cancellation of the successfully established F1 connection between the first node and the third node, and the node identifier and / or IP address of the new target F1 termination anchor node CU.

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