A method, apparatus and system for releasing an F1 connection

Abstract

The embodiment of the application provides a method, device and system for releasing F1 connection, the method is used for IAB node, the method comprises the following steps: receiving a first message from a source IAB host node, the first message is used for indicating that the centralized unit CU of the IAB host node connected with the IAB node changes; according to the first message, the F1 connection between the CU of the source IAB host node is released. Therefore, the IAB node in the application can release the F1 connection in time under the indication of the source IAB host, avoid the resource waste caused by not releasing the F1 connection in time, or release the F1 connection too early, but the new F1 connection has not been established, leading to the terminal service interruption, improve the reliability of releasing the F1 connection, and ensure the IAB communication performance.

Description

Technical Field

[0001] This application relates to the field of communications, and in particular to a method, apparatus and system for releasing an F1 connection. Background Technology

[0002] In 3GPP (3rd Generation Partnership Project) Rel-15 (Release-15) NR (New Radio), the gNB (next generation node base station) can adopt a CU (Central Unit) - DU (Distributed Unit) separation architecture, that is, the gNB consists of one gNB-CU and one or more gNB-DUs.

[0003] In 3GPP Rel-15 IAB (Integrated Access and Backhaul), two types of nodes are introduced: IAB node and IAB donor. The IAB donor can be a gNB.

[0004] Mobility refers to the handover of a UE (User Equipment) from one cell to another; therefore, mobility is also generally referred to as handover. In this application, it will be referred to as handover.

[0005] In 3GPP Rel-16 IAB, only the Intra-donor-CU (within the host CU) handover scenario is considered, without considering the Inter-donor-CU (between host CUs) handover scenario, and no optimization scheme for releasing the source F1 connection between the IAB node and the source IAB donor-CU in the Inter-donor-CU handover scenario is disclosed. Summary of the Invention

[0006] This application provides a method, apparatus, and system for releasing F1 connections. In Inter-CU handover scenarios, IAB nodes (including the switching IAB node and its downstream IAB nodes) can determine from the source IAB host that the CU of the host node to which the IAB node is connected has changed, thereby allowing the IAB node to release the F1 connection in a timely manner. This avoids resource waste caused by failure to release the F1 connection in a timely manner, or premature release of the F1 connection before a new F1 connection is established, which could lead to interruption of terminal services. This improves the reliability of releasing the F1 connection and ensures the performance of IAB communication.

[0007] In a first aspect, embodiments of this application provide a method for releasing an F1 connection, the method being used to access a backhaul integrated IAB node, the method comprising:

[0008] Receive a first message from the source IAB host node, the first message being used to indicate a change in the centralized unit (CU) of the IAB host node to which the IAB node is connected;

[0009] Release the F1 connection between the CU and the source IAB host node according to the first message;

[0010] The source IAB host node is the IAB host node that the IAB node was connected to before the CU of the connected IAB host node was changed.

[0011] The F1 connection between the IAB node and the CU of the source IAB host node can be referred to as the source F1 connection.

[0012] In one possible implementation, the first message includes first information, which is used to indicate that the CU of the IAB host node to which the IAB node is connected has changed or a cross-host CU switch has occurred.

[0013] In one possible implementation, the first message is an F1 application layer protocol F1AP message.

[0014] In one possible implementation, receiving the first message from the source IAB host node includes:

[0015] The first message is received from the source IAB host node through the target IAB host node;

[0016] The target IAB host node is the IAB host node that the IAB node connects to after the CU of the connected IAB host node is changed.

[0017] In one possible implementation, receiving the first message from the source IAB host node via the target IAB host node includes:

[0018] Based on the IP address assigned to the IAB node by the target IAB host node, establish a first TNL association with the source IAB host node;

[0019] Based on the first TNL association, the first message is received from the source IAB host node through the target IAB host node.

[0020] In one possible implementation, the first message further includes second information, which includes the IP address assigned to the IAB node by the source IAB host node and / or the identifier of the CU of the source IAB host node.

[0021] In one possible implementation, receiving the first message from the source IAB host node via the target IAB host node includes:

[0022] A second TNL association is established with the source IAB host node based on the IP address assigned to the IAB node by the source IAB host node;

[0023] Based on the second TNL association, the first message is received from the source IAB host node through the target IAB host node.

[0024] In one possible implementation, the first message includes an inner IP header and an outer IP header, wherein the IP address of the IAB node included in the inner IP header corresponds to the source IAB host node, and the IP address of the IAB node included in the outer IP header corresponds to the target IAB host node.

[0025] In one possible implementation, releasing the F1 connection with the CU of the source IAB host node according to the first message includes:

[0026] Start the timer;

[0027] When the timer expires, the F1 connection between the source IAB host node and the CU is released.

[0028] In one possible implementation, the first message may also include information about the duration of the timer.

[0029] Secondly, embodiments of this application provide a method for releasing an F1 connection, the method being used in a source access backhaul integrated IAB host node, the method comprising:

[0030] A first message is determined, which is used to indicate a change in the centralized unit (CU) of the IAB host node connected to the IAB node.

[0031] Send the first message to the IAB node to release the F1 connection between the IAB node and the CU of the source IAB host node;

[0032] The source IAB host node is the IAB host node that the IAB node was connected to before the CU of the connected IAB host node was changed.

[0033] In one possible implementation, the first message includes first information, which is used to indicate that the CU of the IAB host node to which the IAB node is connected has changed or a cross-host CU switch has occurred.

[0034] In one possible implementation, the first message is an F1 application layer protocol F1AP message.

[0035] In one possible implementation, sending the first message to the IAB node includes:

[0036] The first message is sent to the IAB node through the target IAB host node;

[0037] The target IAB host node is the IAB host node that the IAB node connects to after the CU of the connected IAB host node is changed.

[0038] In one possible implementation, sending the first message to the IAB node via the target IAB host node includes:

[0039] Establish a first TNL association with the IAB node, wherein the first TNL association corresponds to the IP address allocated by the target IAB host node to the IAB node;

[0040] Based on the first TNL association, a first message is sent from the target IAB host node to the IAB node.

[0041] In one possible implementation, the first message further includes second information, which includes the IP address assigned to the IAB node by the source IAB host node and / or the identifier of the CU of the source IAB host node.

[0042] In one possible implementation, sending the first message to the IAB node via the target IAB host node includes:

[0043] A second TNL association is established with the IAB node, and the second TNL association corresponds to the IP address allocated to the IAB node by the source IAB host node;

[0044] Based on the second TNL association, the first message is sent to the IAB node through the target IAB host node.

[0045] One possible implementation also includes:

[0046] Send the IP address assigned to the IAB node by the source IAB host node to the CU of the target IAB host node. The IP address assigned to the IAB node by the source IAB host node is used to determine the mapping relationship.

[0047] The mapping relationship is the correspondence between the IP address allocated by the source IAB host node to the IAB node and the Backhaul Adaptation Protocol (BAP) address allocated by the target IAB host node to the IAB node.

[0048] In one possible implementation, the first message includes an inner IP header and an outer IP header, wherein the IP address of the IAB node included in the inner IP header corresponds to the target IAB host node, and the IP address of the IAB node included in the outer IP header corresponds to the source IAB host node.

[0049] In one possible implementation, the first message also includes information about the duration of the timer.

[0050] Thirdly, embodiments of this application provide a device for releasing an F1 connection, the device being used to access a backhaul integrated IAB node, the device comprising:

[0051] The receiving module is configured to receive a first message from the source IAB host node, the first message being used to indicate a change in the centralized unit (CU) of the IAB host node to which the IAB node is connected.

[0052] The release module is configured to release the F1 connection between the CU and the source IAB host node according to the first message;

[0053] The source IAB host node is the IAB host node that the IAB node was connected to before the CU of the connected IAB host node was changed.

[0054] Fourthly, embodiments of this application provide a device for releasing an F1 connection, the device being used for a source access backhaul integrated IAB host node, the device comprising:

[0055] The determination module is configured to determine a first message, which is used to indicate that the CU of the IAB host node connected to the IAB node has changed.

[0056] The sending module is configured to send a first message to the IAB node to release the F1 connection between the IAB node and the CU of the source IAB host node.

[0057] The source IAB host node is the IAB host node that the IAB node was connected to before the CU of the connected IAB host node was changed.

[0058] Fifthly, embodiments of this application provide a communication device, characterized in that the communication device includes: a processor coupled to a memory; the memory is used to store computer instructions; the processor is used to execute the computer instructions, causing the method described in the first aspect to be executed.

[0059] In a sixth aspect, embodiments of this application provide a communication device, characterized in that the communication device includes: a processor coupled to a memory; the memory is used to store computer instructions; the processor is used to execute the computer instructions, causing the method described in the second aspect above to be executed.

[0060] In a seventh aspect, embodiments of this application provide a communication system including two or more of an IAB node, a source IAB host node, and a target IAB host node; wherein the IAB node is used to execute the method described in the first aspect above; and the source IAB host node is used to execute the method described in the second aspect above.

[0061] Eighthly, embodiments of this application provide a computer storage medium, the computer storage medium including computer instructions, which, when executed, cause the method described in the first aspect to be performed.

[0062] Ninthly, embodiments of this application provide a computer storage medium including computer instructions that, when executed, cause the method described in the second aspect above to be performed.

[0063] In a tenth aspect, embodiments of this application provide an apparatus for performing the methods described in the first and second aspects above. Embodiments of this application provide a method, apparatus, and system for releasing an F1 connection. By determining a first message, which instructs the IAB node to change the CU of the IAB host node to be connected, and sending the first message to the IAB node, the IAB node releases the F1 connection with the CU of the source IAB host node according to the first message. This achieves timely release of the source F1 connection by the IAB node under the instruction of the source IAB host, avoiding resource waste caused by failure to release the source F1 connection in a timely manner, or communication interruption caused by premature release of the F1 connection, thus improving the reliability and efficiency of releasing the source F1 connection. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of a CU-DU separation structure;

[0065] Figure 2 This is a schematic diagram of the control plane protocol stack under a CU-DU separation structure;

[0066] Figure 3 This is a schematic diagram of a user plane protocol stack under a CU-DU separation structure;

[0067] Figure 4 This is a schematic diagram of a two-hop data backhaul scenario;

[0068] Figure 5 A schematic diagram of the control plane protocol stack for two-hop data backhaul;

[0069] Figure 6 A schematic diagram of the user plane protocol stack for two-hop data backhaul;

[0070] Figure 7 This is a schematic diagram of an Intra-CU switching scenario;

[0071] Figure 8 This is a schematic diagram of the Intra-CU switching process;

[0072] Figure 9 This is a schematic diagram of an Inter-CU handover scenario provided in an embodiment of this application;

[0073] Figure 10 This is a schematic diagram of another Inter-CU handover scenario provided in an embodiment of this application;

[0074] Figure 11 This is a schematic diagram of another Inter-CU handover scenario provided in an embodiment of this application;

[0075] Figure 12 This is a schematic diagram illustrating a method for releasing an F1 connection according to an embodiment of this application;

[0076] Figure 13 This is a schematic diagram illustrating a method for releasing an F1 connection according to an embodiment of this application;

[0077] Figure 14 A schematic diagram of a protocol stack architecture provided for an embodiment of this application;

[0078] Figure 15 This is a schematic diagram illustrating a method for releasing an F1 connection according to an embodiment of this application;

[0079] Figure 16 A schematic diagram of a protocol stack architecture provided for an embodiment of this application;

[0080] Figure 17 This is a schematic diagram illustrating a method for releasing an F1 connection according to an embodiment of this application;

[0081] Figure 18 A flowchart illustrating a method for releasing an F1 connection provided in an embodiment of this application;

[0082] Figure 19 A flowchart illustrating a method for releasing an F1 connection provided in an embodiment of this application;

[0083] Figure 20 This is a schematic diagram of a device for releasing the F1 connection provided in an embodiment of this application;

[0084] Figure 21 This is a schematic diagram of a device for releasing the F1 connection provided in an embodiment of this application;

[0085] Figure 22 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0086] Figure 23 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application. Detailed Implementation

[0087] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0088] In the description of this specification, terms such as "one embodiment" or "some embodiments" mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0089] In this specification, unless otherwise stated, " / " signifies "or," for example, A / B can mean A or B. "And / or" in this document merely describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Furthermore, in the description of the embodiments in this application, "multiple" refers to two or more.

[0090] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0091] In 3GPP Rel-15 NR, the gNB can adopt a CU-DU separate architecture, meaning that the gNB consists of one gNB-CU and one or more gNB-DUs. Each gNB-DU can only connect to one gNB-CU, and the gNB-CU and gNB-DU are connected via the F1 interface. The gNB-CU and 5GC are connected via the NG interface. Figure 1 As shown.

[0092] In this context, a gNB refers to a node that provides NR (New Radio) user plane and control plane transmission for UE (User Equipment), and may comprise one or more cells. A gNB connects to the 5GC (5G Core Network) via the NG interface and to other gNBs via the Xn interface. The Xn-C interface is used for control plane signaling transmission between two gNBs, while the Xn-U interface is used for user plane data transmission between them. The interface between the gNB and the UE is called the Uu interface.

[0093] gNB-CU can refer to a logical node that includes the gNB's RRC (Radio Resource Control) layer, SDAP (Service Data Adaptation Protocol) layer, and PDCP (Packet Data Convergence Protocol) layer, or the en-gNB's RRC and PDCP layers, used to control one or more gNB-DUs.

[0094] A gNB-DU (Distributed Unit) can refer to a logical node that includes the RLC (Radio Link Control) layer, MAC (Medium Access Control) layer, and PHY (Physical) layer of a gNB or en-gNB. A gNB-DU supports one or more cells, but a cell can only belong to one gNB-DU.

[0095] The UE accesses the gNB-CU through the gNB-DU, meaning that the PHY / MAC / RLC layer functions equivalent to the UE are located on the gNB-DU, and the PDCP / SDAP / RRC layer functions equivalent to the UE are located on the gNB-CU.

[0096] like Figure 2 As shown, for the CP (Control Plane), in the UL (Up Link) direction, the gNB-DU encapsulates the RRC message generated by the UE in an F1AP (F1 Application Protocol) message on the F1 interface and sends it to the gNB-CU; in the DL (Down Link) direction, the gNB-CU encapsulates the RRC message in an F1AP message and sends it to the gNB-DU. The gNB-DU extracts the RRC message from the F1AP message and maps it to the corresponding SRB (Signalling Radio Bearer) on the Uu interface before sending it to the UE. The SRB can be SRB0 / SRB1 / SRB2, etc.

[0097] like Figure 3 As shown, for the UP (User Plane), in the UL direction, the gNB-DU maps the UE data packets received from the DRB (Data Radio Bearer) on the Uu interface to the corresponding GTP (General Packet Radio Service Tunneling Protocol) tunnel and sends them to the gNB-CU; in the DL direction, the gNB-CU maps the UE data packets to the corresponding GTP tunnel and sends them to the gNB-DU. The gNB-DU extracts the UE data packets from the GTP tunnel and maps the UE data packets to the DRB corresponding to the Uu interface and sends them to the UE.

[0098] In 3GPP Rel-15 IAB, two types of nodes were introduced: IAB node and IAB donor. The IAB donor can be a gNB.

[0099] like Figure 4As shown, taking a two-hop data backhaul scenario as an example, where backhaul is referred to as BH, the IAB network adopts a CU-DU separation architecture. That is, the IAB donor consists of two parts: IAB donor-CU (donor-CU) and IAB donor-DU (donor-DU), and the IAB node consists of two parts: IAB node-MT (IAB-MT) and IAB node-DU (IAB-DU). Among them, IAB node-MT (Mobile Terminal 1) can also be called IAB node-UE (IAB-UE).

[0100] For IAB donors, the functions of donor-DU and gNB-DU are similar, and the functions of donor-CU and gNB-CU are similar.

[0101] For IAB nodes, IAB-DU functions similarly to gNB-DU, providing access services to its child nodes. The child nodes of IAB-DU can be UEs or other IAB nodes. IAB-MT has the function of a UE, providing data backhaul to the child nodes of a co-located IAB-DU (i.e., the IAB-DU and IAB-MT belong to the same IAB node).

[0102] Furthermore, IAB nodes can be divided into access IAB nodes and intermediate IAB nodes. Specifically, the IAB node the UE accesses is called the access IAB node, and the IAB nodes on the path between the access IAB node and the IAB donor are called intermediate IAB nodes. For example, ... Figure 4 As shown, when a UE accesses IAB node2, IAB node2 is called the UE's access IAB node (or the UE's parent node), and the UE is called the child node of IAB node2. The link between the UE and IAB node2 is called the access link. IAB node1 is called the intermediate IAB node. The parent node of IAB node1 is the IAB donor (the child node of the IAB donor is IAB node1), and the child node of IAB node1 is IAB node2 (the parent node of IAB node2 is IAB node1). The links between IAB node1 and IAB node2, as well as the links between IAB node1 and the IAB donor, are called backhaul links. The PHY, MAC, and RLC layers, which are equivalent to the UE, are located on the access IAB node (i.e., IAB2-DU), while the PDCP, SDAP, and RRC layers, which are equivalent to the UE, are located on the donor-CU. All IAB nodes adopt an L2 data forwarding architecture. The specific user plane and control plane protocol stacks are as follows:

[0103] like Figure 5 As shown, the control plane protocol stack for two-hop data backhaul establishes an F1 interface between the access IAB node (i.e., IAB2-DU) and the IAB donor (i.e., donor-CU). Specifically, if the IAB donor adopts a CP-UP separation architecture, an F1-C interface is established between IAB2-DU and the donor CU-CP. The UE's RRC messages are encapsulated in the F1AP messages of the F1-C interface for transmission.

[0104] like Figure 6 As shown, the user plane protocol stack for two-hop data backhaul is as follows: If the IAB donor adopts a CP-UP separation architecture, an F1-U interface is established between the IAB2-DU and the donor CU-UP, and a per-UE bearer GTP tunnel is established on this F1-U interface. In other words, each UE DRB established on the interface between the UE and the IAB2-DU corresponds to a separate GTP tunnel on the interface between the IAB2-DU and the donor CU-UP.

[0105] Mobility refers to a UE's handover from one cell to another; therefore, mobility is also generally referred to as handover or migration. In this application, it will be referred to as handover.

[0106] In 3GPP Rel-16 IAB, only the Intra-donor-CU handover scenario is considered, and the Inter-donor-CU handover scenario is not considered.

[0107] In this context, Intra-donor-CU switching refers to switching within the same donor-CU; Inter-donor-CU switching refers to switching between different donor-CUs. That is, Intra-donor-CU switching does not change the donor-CU, and the switching occurs within a single donor-CU; while Inter-donor-CU switching changes the donor-CU.

[0108] like Figure 7 As shown in the diagram, the Intra-donor-CU switching scenario is illustrated using the example of an IAB node directly connected to the IAB host undergoing a switch. The IAB node undergoing the switch can be referred to as the switching IAB node or the migrating IAB node. In this application, it is uniformly referred to as the switching IAB node.

[0109] This scenario can also be extended to multi-hop, meaning that there is at least one other IAB node between the switching IAB node and the IAB host.

[0110] The IAB node handover consists of two parts: IAB-MT and IAB-DU. In this embodiment, the IAB-MT of the handover IAB node is collectively referred to as the handover IAB-MT, and the IAB-DU of the handover IAB node is collectively referred to as the handover IAB-DU. The downstream node of the handover IAB node includes the child node, grandchild node (child node of the child node), and grand-grandchild node of the handover IAB node. The downstream node can be other IAB nodes or the UE.

[0111] Similar to the UE, before the IAB-MT handover, the IAB-MT connects to the source IAB host, that is, it connects to the IAB donor-CU through IAB donor-DU1. After the IAB-MT handover, the IAB-MT connects to the target IAB host, that is, it connects to the IAB donor-CU through IAB donor-DU2.

[0112] Since the IAB donor-CU remains unchanged before and after the IAB-MT switch, the F1 connection between the IAB-DU and the IAB donor-CU remains unchanged.

[0113] Since the IP address (Internet Protocol Address) of IAB-DU is assigned by IABdonor-DU, meaning that the IP address of IAB-DU and the IP address of IAB donor-DU belong to the same network segment or have the same network prefix, once the IAB donor-DU changes, the IP address of IAB-DU will change.

[0114] like Figure 8 The diagram illustrating the IABIntra-donor-CU handover process, taking a multi-hop scenario (where there is at least one other IAB node between the handover IAB node and the IAB donor-DU) as an example, shows the source path as the transmission path between the source parent node and the source IAB donor-DU; and the target path as the transmission path between the target parent node and the target IAB donor-DU. The specific handover process is as follows:

[0115] 8-1. Switch IAB-MT to send an RRC message (i.e., MeasurementReport message) to the source parent node's IAB-DU. The MeasurementReport message is a measurement reporting message.

[0116] 8-2. The source parent node's IAB-DU sends an F1AP message (i.e., a UL RRC Message Transfer message) to the IAB donor-CU, which carries a MeasurementReport message. The UL RRC Message Transfer message is a UL RRC message forwarding message.

[0117] 8-3. The IAB donor-CU sends an F1AP message (i.e., a UEContext Setup Request message) to the IAB-DU of the target parent node for the IAB switchover, to establish the context information for the IAB-MT switchover on the target parent node. The UE Context Setup Request message is a UE context establishment request message.

[0118] 8-4. The target parent node's IAB-DU sends an F1AP message (i.e., a UE Context Setup Response message) to the IAB donor-CU as a response. The UE Context Setup Response message is the UE context establishment response message.

[0119] 8-5. The IAB donor-CU sends an F1AP message (i.e., a UE ContextModification Request message) to the IAB-DU of the source parent node. This message carries an RRCReconfiguration message. The UE ContextModification Request message is a UE context modification request message, and the RRCReconfiguration message is an RRC reconfiguration message.

[0120] The RRCReconfiguration message includes the configuration of the default BH RLC channel (default bearer) and default BAP routing ID (default route) used for UL F1-C / non-F1 service transmission on the target path when switching IAB-MT. F1-C services refer to UE-associated F1AP messages and Non-UE associated F1AP messages, while non-F1 services refer to application layer messages established by IPsec (Internet Protocol Security), application layer messages associated by SCTP (Stream Control Transmission Protocol), or OAM (Operation Administration and Maintenance) services, etc.

[0121] When the IAB donor-DU changes, the RRCReconfiguration message may also include the IP address assigned by the target IAB donor-DU for switching the IAB node (or switching the IAB-DU).

[0122] 8-6. The source parent node's IAB-DU forwards the received RRCReconfiguration message to the switching IAB-MT.

[0123] 8-7. The source parent node's IAB-DU sends an F1AP message (i.e., a UE ContextModification Response message) to the IAB donor-CU as a response. The UE Context Modification Response message is the UE context modification response message.

[0124] 8-8. Switch IAB-MT to initiate a random access procedure to the IAB-DU of the target parent node.

[0125] 8-9. Switch IAB-MT to send an RRCReconfigurationComplete message to the target parent node's IAB-DU. The RRCReconfigurationComplete message is an RRC reconfiguration completion message.

[0126] 8-10. The target parent node's IAB-DU sends a UL RRC Message Transfer message to the IAB donor-CU, which carries an RRCReconfigurationComplete message.

[0127] 8-11. The IAB donor-CU configures the corresponding BH RLC channel and BAP route configuration for the target path of the switched IAB node, and configures the DL bearer mapping on the target IAB donor-DU for the switched IAB node. This configuration process can be performed in advance, for example, immediately after step (8-3).

[0128] 8-12. The F1-C connection update uses the new IP address of the switched IAB-DU. The IAB donor-CU updates the UL BH information associated with each GTP tunnel to the switched IAB node, that is, all F1-U tunnel updates use the new IP address of the switched IAB-DU.

[0129] 8-13. The IAB donor-CU sends an F1AP message (i.e., a UE Context Release Command message) to the IAB-DU of the source parent node. The UE Context Release Command message is a UE context release request message.

[0130] 8-14. The source parent node releases the context of the IAB-DU switching IAB-MT and sends an F1AP message (UE Context Release Complete message) to the IAB donor-CU in response. The UE Context ReleaseComplete message indicates that the UE context release is complete.

[0131] 8-15. IAB donor-CU releases the BH RLCchannel and BAP routing configuration information on the source path between the source parent node and the source IAB donor-DU.

[0132] As can be seen, in the Intra-donor-CU switching scenario, the F1 connection between the IAB-DU and the IAB donor-CU remains unchanged when switching. Similarly, the F1 connection between the downstream node of the IAB node (e.g., other IAB nodes) and the IAB donor-CU also remains unchanged. In other words, switching IAB nodes, switching the child IAB nodes of the IAB node, etc., do not require releasing the F1 connection with the IAB donor-CU.

[0133] However, the handover scenario of the Inter-donor-CU is also a typical handover scenario. In this scenario, the IAB donor-CU will change, which will cause the F1 connection of the switching IAB-DU to change (the current standard only supports one DU connecting to one CU to establish an F1 connection). That is: before the handover, an F1 connection is established between the switching IAB-DU and the source IAB donor-CU; after the handover, the switching IAB-DU needs to establish an F1 connection with the target IAB donor-CU and release the F1 connection with the source IAB donor-CU. Similarly, the F1 connection between the downstream node of the switching IAB node (e.g., other IAB nodes) and the IAB donor-CU also changes, that is, the F1 connection with the source IAB donor-CU needs to be released.

[0134] Therefore, this application provides a method, apparatus, and system for releasing F1 connections, aiming to solve the problem of how an IAB node releases its F1 connection with the source IAB donor-CU in an Inter-donor-CU handover scenario. The IAB node includes: a handover IAB node and a downstream IAB node of the handover IAB node.

[0135] The main application scenarios of this application include:

[0136] Before switching IAB-MT, the IAB-MT switch is performed via the source IAB donor-DU (e.g., Figure 9 The IAB donor-DU1 is connected to the source IAB donor-CU (e.g., ...). Figure 9 In the IAB donor-CU1); after the IAB-MT switch, the switch to IAB-MT is performed through the target IAB donor-DU (e.g., Figure 9 The IAB donor-DU2 is connected to the target IAB donor-CU (e.g., Figure 9 (IABdonor-CU2 in the middle).

[0137] The downstream node for switching IAB nodes can be a UE or another IAB node.

[0138] The above scenario can be further extended to include situations where there is at least one other IAB node between the switching IAB node and the IAB donor-DU, such as... Figure 10 As shown: Before the switch, IAB node1 and IAB node2 were the IAB node to be switched and the source IABdonor-DU (e.g., Figure 10There are other IAB nodes (also known as intermediate IAB nodes) between the IAB donor-DU1 and the target IAB donor-DU. IABnode3 and IABnode4 are for switching between IAB nodes and the target IAB donor-DU (e.g., Figure 10 Other IAB nodes (also known as intermediate IAB nodes) exist between the IAB donor-DU2 and the IAB donor.

[0139] Furthermore, the above scenarios can be further expanded, such as... Figure 11 As shown: Specifically, it includes the following two cases (examples):

[0140] Case 1: Before the switch, the switch IAB-MT is directly connected to the source IAB donor-DU; after the switch, the switch IAB-MT is connected to the target IAB donor-DU through at least one other IAB node.

[0141] Case 2: Before the switchover, the switching IAB-MT is connected to the source IAB donor-DU through at least one other IAB node; after the switchover, the switching IAB-MT is directly connected to the target IAB donor-DU.

[0142] In all the above switching scenarios, switching between IAB-MT and the source IABdonor-CU (such as...) Figures 9 to 11 The path between IAB donor-CU1 and the target IAB donor-CU is called the source path. Switching between IAB-MT and the target IAB donor-CU (e.g., Figures 9 to 11 The path between IAB donor-CU2 and the source IAB donor-DU is called the target path. Alternatively, switching between IAB-MT and source IAB donor-DU (e.g., Figures 9 to 11 The path between IAB donor-DU1 and the target IAB donor-DU is called the source path. Switching between IAB-MT and the target IAB donor-DU (e.g., Figures 9 to 11 The path between IAB donor-DU2 is called the target path.

[0143] The network elements involved in this application include: IAB node and IAB donor. Among them, the IAB node consists of IAB node-DU (abbreviated as IAB-DU) and IAB node-MT (abbreviated as IAB-MT), and the IAB donor consists of IAB donor-CU (abbreviated as Donor-CU) and IAB donor-DU (abbreviated as Donor-DU).

[0144] For the IAB donor, the donor-DU functions similarly to the gNB-DU, primarily implementing the functions of the L1 and L2 protocol stacks, including the PHY layer, MAC layer, and RLC layer. The donor-CU functions similarly to the gNB-CU, primarily implementing the PDCP layer, SDAP layer, and RRC layer.

[0145] For IAB nodes, the IAB-DU functions similarly to the gNB-DU, providing access services to its child nodes. The child nodes of the IAB-DU can be UEs or other IAB nodes. The IAB-MT functions as a UE, providing data backhaul to the child nodes of the co-located IAB-DU.

[0146] The following is a description through specific embodiments.

[0147] If RAN (Radio Access Network) sharing is not considered (i.e., one RAN device is shared by different operators), then a DU can only connect to one CU. In an Inter-donor-CU handover scenario, the IAB node's connected IAB donor changes from the source IAB donor to the target IAB donor. Therefore, the IAB node needs to establish an F1 connection with the target IAB donor and delete / release the F1 connection with the source IAB donor. IAB nodes include: the handover IAB node, and the downstream IAB nodes of the handover IAB node (e.g., child nodes, grandchild nodes, grandchild-grandchild nodes, etc.).

[0148] This application is based on Figure 9 Taking the switching scenario as an example, the solution provided in this application is also applicable to... Figure 10 and Figure 11 The aforementioned scene switching.

[0149] In an IAB scenario, IAB nodes include IAB-MT and IAB-DU, and source IAB donors include source IAB donor-DU and source IAB donor-CU. Deleting / releasing the F1 connection between an IAB node and the source IAB donor refers to the deletion / release of the F1 connection between IAB-DU and source IAB donor-CU. Here, the F1 connection between IAB-DU and source IAB donor-CU is referred to as the source F1 connection, and several specific schemes exist.

[0150] Option 1: The source IAB donor displays an instruction to the IAB node to delete / release the source F1 connection.

[0151] As one possible implementation method, i.e., method 1:

[0152] The source IAB donor can instruct the IAB node to delete / release the source F1 connection through the target IAB donor.

[0153] like Figure 12 As shown, after the IAB-MT completes the handover, for example, after the source IAB donor-CU receives the UE Context Release message sent by the target IAB donor, the source IAB donor-CU sends an F1AP message to the IAB-DU through the target IAB donor. Upon receiving this message, the IAB-DU will delete / release the source F1 connection. This F1AP message can be an existing F1AP message, such as an F1 Remoral Request message, or a newly defined F1AP message.

[0154] Optionally, the F1AP message may carry indication information 1, which is used to indicate donor-CU changes / updates, or to indicate inter-CU switching, so that subsequent IAB-DUs can trigger the establishment of an F1 connection with the target IAB donor-CU.

[0155] To assist the target IAB donor in correctly routing and / or mapping F1AP messages sent from the source IAB donor-CU to the IAB-DU, before the source IAB donor-CU instructs the IAB-DU to delete / release the source F1 connection, the target IAB donor-CU sends the source IAB donor-CU a mapping relationship between the UE-associated (User equipment-associated) F1AP type indication and the DSCP (Difierentiated Services CodePoint) / flow label, and / or a mapping relationship between the Non-UE associated F1AP type indication and the DSCP / flow label. Specifically, the target IAB donor-CU sends the following information to the source IAB donor-CU:

[0156] One or more of the following: F1AP type indicator and DSCP / flow label, wherein the F1AP type indicator includes UE-associated F1AP type indicator and / or Non-UE associated F1AP type indicator. The F1AP type indicator corresponds to the DSCP / flow label.

[0157] The source IAB donor-CU instructs the IAB-DU to delete / release the source F1 connection through the target IAB donor. That is, the F1AP message sent by the source IAB donor-CU to the IAB-DU is encapsulated in an IP packet and routed to the IAB-DU through the target IAB donor-DU. There are several specific implementation methods:

[0158] Method 1-1: The newly created TNL (Transport Network Layer) is the first TNL association.

[0159] Specifically, the F1AP message is sent through a newly established TNL association between the IAB-DU and the source IAB donor-CU.

[0160] In this method 1-1, once the IAB-DU obtains the IP address assigned to it by the target IAB donor, it will establish a new TNL association with the source IAB donor-CU. That is, the IP address corresponding to the newly established TNL association includes: the IP address of the source IAB donor-CU and the IP address assigned to the IAB node by the target IAB donor.

[0161] It is worth noting that in this application, the IP address assigned to the IAB donor is for use by the IAB-DU.

[0162] Optionally, to enable the IAB-DU to delete the F1 connection between the IAB-DU and the source IAB donor-CU after receiving the F1AP message sent by the source IAB donor-CU on the newly established TNL association, the F1AP message may also carry indication information 2, such as... Figure 13 As shown. The instruction information 2 can implicitly or explicitly indicate the deletion of the source F1 connection. For example, instruction information 2 can be the IP address assigned to the IAB node by the source IAB donor, or it can be the identifier of the source IAB donor-CU (e.g., source IAB donor-CU name), or it can be an instruction to delete the source F1 connection (explicit instruction). Based on instruction information 2, the IAB-DU will delete the F1 connection corresponding to that instruction information. Furthermore, the protocol stack architecture corresponding to the above method 1-1 is as follows: Figure 14 As shown.

[0163] Method 1-2: Old TNL (i.e., second TNL association)

[0164] Specifically, the F1AP message is sent via the old TNL association between the IAB-DU and the source IAB donor-CU.

[0165] In this method 1-2, the IP addresses corresponding to the old TNL association established between IAB-DU and source IAB donor-CU include: the IP address of source IAB donor-CU and the IP address assigned by source IAB donor to IAB node.

[0166] In order for the target IAB donor-DU to perform the corresponding routing and bearer mapping based on the IP packets received from the source IAB donor-CU, the source IAB donor-CU needs to send the IP address assigned to the IAB node by the source IAB donor to the target IAB donor-CU. The target IAB donor-CU then sends the mapping relationship between the IP address assigned to the IAB node by the source IAB donor and the BAP address assigned to the IAB node by the target IAB donor-CU to the target IAB donor-DU. Figure 15 As shown. Specifically, the target IAB donor-CU sends the IP address assigned to the IAB node by the source IAB donor and the BAP address assigned to the IAB node by the target IAB donor-CU to the target IAB donor-DU. There is a correspondence between the IP address assigned to the IAB node by the source IAB donor and the BAP address assigned to the IAB node by the target IAB donor-CU. Furthermore, the protocol stack architecture corresponding to methods 1-2 above is the same as the protocol stack architecture corresponding to method 1-1 above.

[0167] Methods 1-3: Using IP-in-IP transmission, i.e., double IP encapsulation.

[0168] like Figure 16 As shown, the F1AP message sent from the source IAB donor-CU to the IAB-DU undergoes two IP encapsulations. Taking the following data transmission as an example, in the first IP encapsulation (referred to as the outer IP for convenience), the destination IP address is the IP address assigned to the IAB node by the source IAB donor, and the source IP address is the IP address of the source IAB donor-CU. In the second IP encapsulation (referred to as the inner IP for convenience), the destination IP address is the IP address assigned to the IAB node by the target IAB donor, and the source address is the IP address of the source IAB donor-CU.

[0169] In order for the source IAB donor-CU to know the IP address that the target IAB donor has assigned to the IAB node, the target IAB donor-CU needs to send the IP address that the target IAB donor has assigned to the IAB node to the source IAB donor-CU.

[0170] As another possible implementation, namely method 2:

[0171] The source IAB donor can directly instruct the IAB node to delete / release the source F1 connection via the source path. For example... Figure 17 As shown, before the IAB-MT receives the handover command (or performs the handover), the source IAB donor-CU sends an F1AP message to the IAB-DU. Upon receiving this message, the IAB-DU will delete / release the source F1 connection. This F1AP message can be a standard F1AP message, such as an F1Removal Request message, or a newly defined F1AP message. Optionally, the F1AP message may also carry indication information 1, which is used to instruct the donor-CU to change / update, or to instruct the inter-CU to switch, so that the IAB-DU can subsequently trigger the establishment of an F1 connection with the target IAB donor-CU.

[0172] Option 2: Implicitly instruct the IAB node to delete / release the source F1 connection

[0173] As one possible implementation, after IAB-MT receives a switching command (i.e., when the RRC reconfiguration message carries the ReconfigurationWithSync parameter), IAB-MT notifies IAB-DU through an internal interface so that IAB-DU can automatically delete / release the source F1 connection.

[0174] As one possible implementation, after receiving a new configuration, or after the new configuration of the IAB-DU is activated, the source F1 connection will be automatically deleted / released. The new configuration refers to the configuration of the IAB-DU under the target IAB donor, and includes at least one of the following information: the new cell identifier of the IAB-DU cell under the target IAB donor (e.g., Cell identity or CGI (Cell Global Identity)) or the system broadcast message of the IAB-DU cell. Optionally, the IAB-DU can obtain the new configuration from the OAM server, or the IAB-DU can obtain the new configuration from the target IAB donor.

[0175] One possible implementation is that the source IAB donor or the target IAB donor configures a timer for the IAB node. When the timer expires, the IAB-DU will automatically delete / release the source F1 connection. Specifically, there are several possibilities for the IAB node to start this timer, including: once the IAB-MT receives a handover command, or once the IAB-DU receives a new configuration, the IAB node starts the timer, and when the timer expires, the IAB-DU automatically deletes / releases the source F1 connection.

[0176] Next, please refer to Figure 18 , Figure 18 This is a flowchart illustrating a method for releasing an F1 connection, provided in an embodiment of this application. This method can be used on a source IAB host node, which includes a source donor-CU and a source donor-DU, for example: Figures 9 to 11 In any Inter-CU switching scenario, IAB donor-CU1 and IABdonor-DU1 are used. For example... Figure 18 As shown, the method for releasing the F1 connection may include the following steps:

[0177] S181. Determine the first message, which is used to indicate a change in the CU of the IAB host node connected to the IAB node.

[0178] Specifically, the source IAB host node can refer to the IAB host node that the IAB node was connected to before the CU of the connected IAB host node was changed.

[0179] An IAB node can refer to either the switching IAB node or its downstream node. The downstream node can include the switching IAB node's child nodes, grandchild nodes (children of child nodes), and so on. Furthermore, this downstream node can be another IAB node or a UE. Based on the measurement results reported by the switching IAB node, the source IAB host node can execute a handover decision, determining whether the switching IAB node needs to be switched from the source IAB host node to the target IAB host node. Therefore, based on the decision result, the source IAB host node can determine whether the CU of the IAB host node connected to the IAB node will change.

[0180] As an example, the message name of the first message can implicitly indicate a change in the CU of the IAB host node to which the IAB node is connected. For example: F1 Removal Request message, or a newly defined message (e.g., F1 Release Request message).

[0181] As another embodiment, the information carried in the first message explicitly or implicitly indicates a change in the CU of the IAB host node to which the IAB node is connected. For example, the first message includes first information used to indicate a change in the CU of the IAB host node to which the IAB node is connected, or a switchover between host CUs. For instance, the first information could be as follows: Figure 12 The instruction information shown is 1.

[0182] As another embodiment, the first message can be an F1AP message. This F1AP message can be a standard F1AP message, such as an F1 Removal Request message; it can also be a newly defined F1AP message. Optionally, the F1AP message can carry first information, which is used to indicate a change in the CU of the IAB host node connected to the IAB node or a switchover between host CUs.

[0183] As another embodiment, the first message may be a switching command generated by the target IAB host node (i.e., the ReconfigurationWithSync parameter carried in the RRC reconfiguration message). This switching command carries first information, which is used to indicate that the CU of the IAB host node to which the IAB node is connected has changed or a cross-host CU switch has occurred.

[0184] As another embodiment, the first message may be a message configuring configuration information for the DU of the IAB node under the target IAB host node. This configuration information may include: the new cell identifier (e.g., Cell identity or CGI) of the IAB-DU cell under the target IAB donor and / or the system broadcast message of the IAB-DU cell. This configuration information may implicitly indicate a change in the CU of the IAB host node to which the IAB node is connected, or a handover to a cross-host CU. Optionally, this configuration information may be provided by the OAM server or by the target IAB host node.

[0185] As another embodiment, the first message may also include information about the duration of a timer. The duration of this timer can be configured by the source IAB host node, the target IAB host node, or it can be predetermined by the communication protocol. That is, when the IAB node receives the first message, it first starts the timer. After the timer expires, it releases the F1 connection with the CU of the source IAB host node. This allows the IAB node sufficient processing time before releasing the F1 connection, improving the reliability of the F1 connection release.

[0186] S182. Send the first message to the IAB node to release the F1 connection between the IAB node and the CU of the source IAB host node.

[0187] Specifically, the F1 connection between an IAB node and the CU of the source IAB host node can be simply referred to as the source F1 connection. The F1 connection between an IAB node and the CU of the target IAB host node can be simply referred to as the target F1 connection.

[0188] As an example, the source IAB host can send the first message to the IAB node via the source path. For instance, before the IAB node switches from the source path to the target path, the source IAB host can send the first message to the IAB node via the source path. For example, such as... Figure 17 As shown, before the IAB-MT receives the handover command (or performs the handover), the source IABdonor-CU sends an F1AP message to the IAB-DU. After receiving the message, the IAB-DU will delete / release the source F1 connection.

[0189] As another embodiment, the source IAB host node can send the first message to the IAB node through the target IAB host node. For example, after the IAB node switches from the source path to the target path, the source IAB host node can send the first message to the IAB node through the target IAB host node.

[0190] The target IAB host node can be the IAB host node that the IAB node connects to after the CU of the connected IAB host node changes. For example: Figures 9 to 11 In any Inter-CU switching scenario, IAB donor-CU2 and IAB donor-DU2 are involved. In this application, the source IAB host node sends a first message to the IAB node through the target IAB host node; specifically, the source IAB host node sends the first message to the target IAB donor-DU2 through the target IAB donor-DU2. Figures 9 to 11 In any Inter-CU handover scenario, the IAB donor-DU2 sends the first message to the IAB node; that is, the transmission of the first message does not pass through the target IAB donor-CU. Figures 9 to 11 (IAB donor-CU2 in any Inter-CU handover scenario).

[0191] It should be understood that the source IAB host node can route the first message to the target IAB host node via a wired connection. After receiving the first message, the target IAB host node can further route and forward the first message to the IAB node through the target path.

[0192] The source path mentioned above can refer to the transmission path between the source parent node and the source IAB donor-CU; the destination path can refer to the transmission path between the target parent node and the target IAB donor-CU. For example: Figures 9 to 11In this context, the path between IAB-MT and IAB donor-CU1 is called the source path, and the path between IAB-MT and IAB donor-CU2 is called the target path. Alternatively, the source path can refer to the transmission path between the source parent node and the source IAB donor-DU; the target path can refer to the transmission path between the target parent node and the target IAB donor-DU. For example: Figures 9 to 11 In this process, the path between IAB-MT and IAB donor-DU1 is called the source path, and the path between IAB-MT and IAB donor-DU2 is called the target path.

[0193] For example, such as Figure 12 As shown, after the IAB-MT completes the handover, for example, after the source IAB donor-CU receives the UE Context Release message sent by the target IAB donor, the source IAB donor-CU sends an F1AP message to the IAB-DU through the target IAB donor. Upon receiving this message, the IAB-DU will delete / release the source F1 connection. This F1AP message can be an existing F1AP message, such as an F1 Removal Request message, or a newly defined F1AP message.

[0194] As can be seen from the above embodiments, by determining the first message, which is used to instruct the CU of the IAB host node connected to the IAB node to change, and sending the first message to the IAB node, the IAB node can release the F1 connection with the CU of the source IAB host node according to the first message. This enables the IAB node to release the F1 connection in a timely manner under the instruction of the source IAB host, avoiding resource waste caused by not releasing the F1 connection in a timely manner, or prematurely releasing the F1 connection without establishing a new F1 connection, which would lead to the interruption of terminal services. This improves the reliability of releasing the F1 connection and ensures the performance of IAB communication.

[0195] Furthermore, as an example, when the source IAB host node sends the first message to the IAB node through the target IAB host node, it can first establish a first TNL association with the IAB node. This first TNL association corresponds to the IP address allocated to the IAB node by the target IAB host node. Then, based on the first TNL association, the source IAB host node sends the first message to the IAB node through the target IAB host node.

[0196] Specifically, from the perspective of the IAB node, the IAB node can establish a first TNL association with the source IAB host based on the IP address assigned by the target IAB host. In other words, the first TNL association is triggered by the IAB node and established with the source IAB host node. For a detailed explanation of its implementation, please refer to the newly created TNL in method 1-1 above.

[0197] Optionally, the first message sent based on the first TNL association may further include second information, which includes the IP address assigned to the IAB node by the source IAB host node and / or the identifier of the CU of the source IAB host node; or, the second information includes indication information showing that the IAB node should delete the source F1 connection. For example, the second information may be as follows: Figure 13 The instruction information shown is 2.

[0198] As another embodiment, when the source IAB host node sends the first message to the IAB node through the target IAB host node, it can do so by establishing a second TNL association with the IAB node. The second TNL association corresponds to the IP address allocated to the IAB node by the source IAB host node. Based on the second TNL association, the first message is sent to the IAB node through the target IAB host node.

[0199] Specifically, the second TNL association is triggered by the IAB node and established with the source IAB host node. Its specific implementation process can be found in the old TNL of method 1-2 above. It is worth noting that when an IAB node initially connects to the source IAB host node, before establishing a source F1 connection, the IAB node can establish a second TNL association with the source IAB host node based on the IP address assigned to it by the source IAB host node. When the IAB node performs a handover, the source IAB host node can send a first message to the IAB node through the target IAB host node based on the already established second TNL association.

[0200] Optionally, before sending the first message to the IAB node through the target IAB host node based on the second TNL association, the source IAB host may also send the IP address assigned to the IAB node by the source IAB host node to the CU of the target IAB host node. The IP address assigned to the IAB node by the source IAB host node is used to determine the mapping relationship; wherein, the mapping relationship is the correspondence between the IP address assigned to the IAB node by the source IAB host node and the BAP address assigned to the IAB node by the target IAB host node. For example, this mapping relationship can be as follows: Figure 15 The mapping relationship is shown.

[0201] As another embodiment, when the source IAB host sends the first message to the IAB node through the target IAB host node, the first message may include an inner IP header and an outer IP header. The IP address of the IAB node included in the inner IP header corresponds to that of the target IAB host node, and the IP address of the IAB node included in the outer IP header corresponds to that of the source IAB host node. The specific implementation process can be found in the IP-in-IP transmission method of methods 1-3 above, where the source IAB host performs IP encapsulation twice on the first message.

[0202] It should be understood that the inner layer here refers to the second IP encapsulation process, and the outer layer refers to the first IP encapsulation process. Optionally, the IP address of the IAB node included in the inner layer can be the IP address assigned by the target IAB host node, and the IP address of the IAB node included in the outer layer can be the IP address assigned by the source IAB host node. For example, such as... Figure 16 As shown, the F1AP message sent from the source IAB donor-CU to the IAB-DU undergoes two IP encapsulations. Taking the following data transmission as an example, in the first IP encapsulation, the destination IP address is the IP address assigned to the IAB node by the source IAB donor, and the source IP address is the IP address of the source IAB donor-CU. In the second IP encapsulation, the destination IP address is the IP address assigned to the IAB node by the target IAB donor, and the source address is the IP address of the source IAB donor-CU.

[0203] As can be seen from the above embodiments, when the source IAB host sends the first message to the IAB node through the target IAB host node, it can send the first message to the IAB node through various implementation methods such as first TNL association, second TNL association, and double IP encapsulation, i.e., IP-in-IP transmission, thereby enriching the diversity of the first message sending methods and meeting the individual needs of different communication functions.

[0204] See Figure 19 , Figure 19 This is a flowchart illustrating a method for releasing an F1 connection, provided in an embodiment of this application. This method for releasing an F1 connection can be used with IAB nodes, including IAB-MT and IAB-DU, for example: Figures 9 to 11 In any Inter-CU switching scenario, IAB-MT and IAB-DU are used. For example... Figure 19 As shown, the method for releasing the F1 connection may include the following steps:

[0205] S191. Receive a first message from the source IAB host node, the first message being used to indicate a change in the CU of the IAB host node to which the IAB node is connected.

[0206] Specifically, the source IAB host node can refer to the IAB host node that the IAB node was connected to before the CU of the connected IAB host node was changed.

[0207] An IAB node can refer to the switching IAB node or its downstream node. The downstream node of the switching IAB node can include its child nodes, grandchild nodes (children of child nodes), and so on. Furthermore, this downstream node can be another IAB node or a UE (User Equipment).

[0208] Regarding the first message:

[0209] As an example, the message name of the first message can implicitly indicate a change in the CU of the IAB host node to which the IAB node is connected. For example: F1 Removal Request message, or a newly defined message (e.g., F1 Release Request message).

[0210] As another embodiment, the information carried in the first message explicitly or implicitly indicates a change in the CU of the IAB host node to which the IAB node is connected. For example, the first message includes first information used to indicate a change in the CU of the IAB host node to which the IAB node is connected, or a switchover between host CUs. For instance, the first information could be as follows: Figure 12 The instruction information shown is 1.

[0211] As another embodiment, the first message can be an F1AP message. This F1AP message can be an F1 AP message, such as an F1 Removal Request message; it can also be a newly defined F1AP message. Optionally, the F1AP message can carry first information, which is used to indicate that the CU of the IAB host node connected to the IAB node has changed or a cross-host CU switch has occurred.

[0212] As another embodiment, the first message may be a switching command generated by the target IAB host node (i.e., the ReconfigurationWithSync parameter carried in the RRC reconfiguration message). This switching command carries first information, which is used to indicate that the CU of the IAB host node to which the IAB node is connected has changed or a cross-host CU switch has occurred.

[0213] As another embodiment, the first message may be a message configuring configuration information for the DU of the IAB node under the target IAB host node. This configuration information may include: the new cell identifier (e.g., CeU identity or CGI) of the IAB-DU cell under the target IAB donor and / or the system broadcast message of the IAB-DU cell. This configuration information may implicitly indicate a change in the CU of the IAB host node to which the IAB node is connected, or a handover to a cross-host CU. Optionally, this configuration information may be provided by the OAM server or by the target IAB host node.

[0214] Regarding the receiving method:

[0215] As an example, an IAB node can receive the first message from the source IAB host node via the source path. For instance, before switching from the source path to the target path, the IAB node can receive the first message from the source IAB host node via the source path. For example, such as... Figure 17 As shown, before the IAB-MT receives the handover command (or performs the handover), the source IABdonor-CU sends an F1AP message to the IAB-DU. After receiving the message, the IAB-DU will delete / release the source F1 connection.

[0216] As another embodiment, an IAB node can receive the first message from the source IAB host node through the target IAB host node. For example, after an IAB node switches from the source path to the target path, the IAB node can receive the first message from the source IAB host node through the target IAB host node.

[0217] The target IAB host node can be the IAB host node that the IAB node connects to after the CU of the connected IAB host node changes. For example: Figures 9 to 11 In any Inter-CU switching scenario, IAB donor-CU2 and IAB donor-DU2 are involved. In this application, the source IAB host node sends a first message to the IAB node through the target IAB host node; specifically, the source IAB host node sends the first message to the target IAB donor-DU2 through the target IAB donor-DU2. Figures 9 to 11 In any Inter-CU handover scenario, the IAB donor-DU2 sends the first message to the IAB node; that is, the transmission of the first message does not pass through the target IAB donor-CU. Figures 9 to 11 (IAB donor-CU2 in any Inter-CU handover scenario).

[0218] It should be understood that since the source IAB host node can route the first message to the target IAB host node via a wired connection, and the target IAB host node can further route and forward the first message to the IAB node through the target path after receiving the first message, the IAB node can receive the first message from the source IAB host node through the target IAB host node.

[0219] The source path mentioned above can refer to the transmission path between the source parent node and the source IAB donor-CU; the destination path can refer to the transmission path between the target parent node and the target IAB donor-CU. For example: Figures 9 to 11 In this context, the path between IAB-MT and IAB donor-CU1 is called the source path, and the path between IAB-MT and IAB donor-CU2 is called the target path. Alternatively, the source path can refer to the transmission path between the source parent node and the source IAB donor-DU; the target path can refer to the transmission path between the target parent node and the target IAB donor-DU. For example: Figures 9 to 11 In this process, the path between IAB-MT and IAB donor-DU1 is called the source path, and the path between IAB-MT and IAB donor-DU2 is called the target path.

[0220] For example, such as Figure 12 As shown, after the IAB-MT completes the handover, for example, after the source IAB donor-CU receives the UE Context Release message sent by the target IAB donor, the source IAB donor-CU sends an F1AP message to the IAB-DU through the target IAB donor. Upon receiving this message, the IAB-DU will delete / release the source F1 connection. This F1AP message can be an existing F1AP message, such as an F1 Removal Request message, or a newly defined F1AP message.

[0221] S192. Release the F1 connection between the source IAB host node and the CU according to the first message.

[0222] Specifically, after receiving the first message, the IAB node can choose to immediately release the F1 connection with the CU of the source IAB host node, or it can choose to delay for a certain period of time before releasing the F1 connection with the CU of the source IAB host node.

[0223] As an example, the IAB node can start a timer. When the timer expires, it releases the F1 connection with the CU of the source IAB host node. This allows the IAB node some processing time before releasing the source F1 connection, thereby improving the reliability of releasing the source F1 connection. The duration of this timer can be configured by the source IAB host node, the target IAB host node, or it can be predetermined by the communication protocol.

[0224] As another embodiment, the first message includes information about the duration of the timer, so that the IAB node can first obtain the duration of the timer according to the first message, and then start the corresponding timer according to the duration, until the corresponding timer expires and then release the F1 connection with the CU of the source IAB host node.

[0225] As can be seen from the above embodiments, by receiving a first message sent by the source IAB host node, which is used to indicate that the CU of the IAB host node connected to the IAB node has changed, and releasing the F1 connection with the CU of the source IAB host node according to the first message, the IAB node can release the F1 connection in a timely manner under the instruction of the source IAB host, thereby avoiding the waste of resources caused by not releasing the F1 connection in a timely manner, or releasing the F1 connection too early without establishing a new F1 connection, which would lead to the interruption of terminal services, improve the reliability of releasing the F1 connection, and ensure the performance of IAB communication.

[0226] Furthermore, as an example, when an IAB node receives a first message from a source IAB host node through a target IAB host node, it can first establish a first TNL association with the source IAB host node based on the IP address assigned to the IAB node by the target IAB host node; and then, based on the first TNL association, receive the first message from the source IAB host node through the target IAB host node.

[0227] Specifically, from the perspective of the IAB node, the IAB node can establish a first TNL association with the source IAB host based on the IP address assigned by the target IAB host. In other words, the first TNL association is triggered by the IAB node and established with the source IAB host node. For a detailed explanation of the implementation process, please refer to the newly established TNL in Method 1-1 above.

[0228] Optionally, the first message received based on the first TNL association may further include second information, which includes the IP address assigned to the IAB node by the source IAB host node and / or the identifier of the CU of the source IAB host node, or the second information includes indication information showing that the IAB node deletes the source F1 connection. For example, the second information may be as follows: Figure 13 The instruction information shown is 2.

[0229] As another embodiment, when an IAB node receives a first message from a source IAB host node through a target IAB host node, it can establish a second TNL association with the source IAB host node based on the IP address assigned to the IAB node by the source IAB host node; and based on the second TNL association, it can receive the first message from the source IAB host node through the target IAB host node.

[0230] Specifically, the second TNL association is triggered by the IAB node and established with the source IAB host node. Its specific implementation process can be found in the old TNL of method 1-2 above. It is worth noting that when an IAB node initially connects to the source IAB host node, before establishing a source F1 connection, the IAB node can establish a second TNL association with the source IAB host node based on the IP address assigned to it by the source IAB host node. When the IAB node performs a handover, the source IAB host node can send a first message to the IAB node through the target IAB host node based on the already established second TNL association.

[0231] As another embodiment, when an IAB node receives a first message from a source IAB host node through a target IAB host node, the first message may include an inner IP header and an outer IP header. The IP address of the IAB node included in the inner IP header corresponds to that of the target IAB host node, and the IP address of the IAB node included in the outer IP header corresponds to that of the source IAB host node. The specific implementation process can be found in the IP-in-IP transmission methods of methods 1-3 described above, where the source IAB host node performs two IP encapsulations on the first message.

[0232] It should be understood that the inner layer here refers to the second IP encapsulation process, and the outer layer refers to the first IP encapsulation process. Optionally, the IP address of the IAB node included in the inner layer can be the IP address assigned by the target IAB host node, and the IP address of the IAB node included in the outer layer can be the IP address assigned by the source IAB host node. For example, such as... Figure 16 As shown, the F1AP message sent from the source IAB donor-CU to the IAB-DU undergoes two IP encapsulations. Taking the following data transmission as an example, in the first IP encapsulation, the destination IP address is the IP address assigned to the IAB node by the source IAB donor, and the source IP address is the IP address of the source IAB donor-CU. In the second IP encapsulation, the destination IP address is the IP address assigned to the IAB node by the target IAB donor, and the source address is the IP address of the source IAB donor-CU.

[0233] As can be seen from the above embodiments, when an IAB node receives a first message from a source IAB host node through a target IAB host node, it can receive the first message from the source IAB host node through various implementation methods such as first TNL association, second TNL association, and double IP encapsulation, i.e., IP-in-IP transmission. This enriches the diversity of first message reception and meets the individual needs of different communication functions.

[0234] See Figure 20 , Figure 20 This is a schematic diagram of a device for releasing an F1 connection, provided in an embodiment of this application. The device for releasing an F1 connection can be used in a source IAB host node, which includes a source donor-CU and a source donor-DU, for example: Figures 9 to 11 In any Inter-CU switching scenario, IAB donor-CU1 and IAB donor-DU1. For example... Figure 20 As shown, the device for releasing the F1 connection may include:

[0235] The determination module 201 is configured to determine a first message, the first message being used to indicate that the CU of the IAB host node connected to the IAB node has changed.

[0236] The sending module 202 is configured to send a first message to the IAB node to release the F1 connection between the IAB node and the CU of the source IAB host node.

[0237] The source IAB host node is the IAB host node that the IAB node was connected to before the CU of the connected IAB host node was changed.

[0238] Specifically, the source IAB host node can refer to the IAB host node that the IAB node was connected to before the CU of the connected IAB host node changed. The IAB node can refer to the switching IAB node or its downstream node. The downstream node of the switching IAB node can include its child nodes, grandchild nodes (children of child nodes), and so on. Furthermore, this downstream node can be another IAB node or a UE. Based on the measurement results reported by the switching IAB node, the source IAB host node can perform a handover decision to determine whether the switching IAB node needs to be switched from the source IAB host node to the target IAB host node. Therefore, based on the decision result, the source IAB host node can determine whether the CU of the IAB host node connected to the IAB node will change. As an example, the message name of the first message can implicitly indicate a change in the CU of the IAB host node connected to the IAB node. For example: F1 Removal Request message (existing F1AP message), or a newly defined message (e.g., F1 Release Request message).

[0239] In one possible implementation, the first message includes first information, which is used to indicate that the CU of the IAB host node to which the IAB node is connected has changed or a cross-host CU switch has occurred.

[0240] Specifically, the information carried in the first message explicitly or implicitly indicates a change in the CU of the IAB host node to which the IAB node is connected. For example, the first message includes first information used to indicate a change in the CU of the IAB host node to which the IAB node is connected, or a switchover between host CUs. For instance, this first information could be as follows: Figure 12 The instruction information shown is 1.

[0241] In one possible implementation, the first message is an F1 application layer protocol F1AP message.

[0242] Specifically, the F1AP message can be an F1AP message, such as an F1 Removal Request message; or it can be a newly defined F1AP message. Optionally, the F1AP message may carry first information, which is used to indicate that the CU of the IAB host node connected to the IAB node has changed or a cross-host CU switch has occurred.

[0243] In one possible implementation, the sending module 202 includes:

[0244] The sending submodule is configured to send the first message to the IAB node via the target IAB host node;

[0245] Wherein, the target IAB host node is the IAB host node that the IAB node connects to after the CU of the connected IAB host node is changed. For example: Figures 9 to 11 In any Inter-CU switching scenario, IAB donor-CU2 and IABdonor-DU2 are involved. In this application, the source IAB host node sends a first message to the IAB node through the target IAB host node; specifically, the source IAB host node sends the first message to the target IAB donor-DU2 through the target IAB host node. Figures 9 to 11 In any Inter-CU handover scenario, the IAB donor-DU2 sends the first message to the IAB node; that is, the transmission of the first message does not pass through the target IAB donor-CU. Figures 9 to 11 (IAB donor-CU2 in any Inter-CU handover scenario).

[0246] It should be understood that the source IAB host node can route the first message to the target IAB host node via a wired connection. After receiving the first message, the target IAB host node can further route and forward the first message to the IAB node through the target path.

[0247] In one possible implementation, the sending submodule includes:

[0248] The first association unit is configured to establish a first TNL association with the IAB node based on the IP address assigned to the IAB node by the target IAB host node;

[0249] The first sending unit is configured to send a first message to the IAB node through the target IAB host node based on the first TNL association.

[0250] Specifically, from the perspective of the IAB node, the IAB node can establish a first TNL association with the source LAB host based on the IP address assigned by the target IAB host. In other words, the first TNL association is triggered by the IAB node and established with the source IAB host node. For a detailed explanation of its implementation, please refer to the newly created TNL in method 1-1 above.

[0251] In one possible implementation, the first message further includes second information, which includes the IP address assigned to the IAB node by the source IAB host node and / or the identifier of the CU of the source IAB host node.

[0252] Specifically, the first message sent based on the first TNL association may further include second information. The second information includes the IP address assigned to the IAB node by the source IAB host node and / or the identifier of the CU of the source IAB host node. Alternatively, the second information may include indication information showing that the IAB node deletes the source F1 connection. For example, the second information may be as follows: Figure 13 The instruction information shown is 2.

[0253] In one possible implementation, the sending submodule includes:

[0254] The second association unit is configured to establish a second TNL association with the IAB node based on the IP address assigned to the IAB node by the source IAB host node;

[0255] The second sending unit is configured to send the first message to the IAB node through the target IAB host node based on the second TNL association.

[0256] Specifically, the second TNL association is triggered by the IAB node and established with the source IAB host node. Its specific implementation process can be found in the old TNL of method 1-2 above. It is worth noting that when an IAB node initially connects to the source IAB host node, before establishing a source F1 connection, the IAB node can establish a second TNL association with the source IAB host node based on the IP address assigned to it by the source IAB host node. When the IAB node performs a handover, the source IAB host node can send a first message to the IAB node through the target IAB host node based on the already established second TNL association.

[0257] One possible implementation also includes:

[0258] The third sending unit is configured to send the IP address allocated by the source IAB host node to the IAB node to the CU of the target IAB host node. The IP address allocated by the source IAB host node to the IAB node is used to determine the mapping relationship.

[0259] The mapping relationship is the correspondence between the IP address allocated by the source IAB host node to the IAB node and the Backhaul Adaptation Protocol (BAP) address allocated by the target IAB host node to the IAB node.

[0260] Specifically, before sending the first message to the IAB node through the target IAB host node based on the second TNL association, the source IAB host may also send the IP address assigned to the IAB node by the source IAB host node to the CU of the target IAB host node.

[0261] In one possible implementation, the first message includes an inner IP header and an outer IP header, wherein the IP address of the IAB node included in the inner IP header corresponds to the target IAB host node, and the IP address of the IAB node included in the outer IP header corresponds to the source IAB host node.

[0262] It should be understood that the inner layer here refers to the second IP encapsulation process, and the outer layer refers to the first IP encapsulation process. Optionally, the IP address of the IAB node included in the inner layer can be the IP address assigned by the target IAB host node, and the IP address of the IAB node included in the outer layer can be the IP address assigned by the source IAB host node. For example, such as... Figure 16 As shown, the F1AP message sent from the source IAB donor-CU to the IAB-DU undergoes two IP encapsulations. Taking the following data transmission as an example, in the first IP encapsulation, the destination IP address is the IP address assigned to the IAB node by the source IAB donor, and the source IP address is the IP address of the source IAB donor-CU. In the second IP encapsulation, the destination IP address is the IP address assigned to the IAB node by the target IAB donor, and the source address is the IP address of the source IAB donor-CU.

[0263] In one possible implementation, the first message also includes information about the duration of the timer.

[0264] Specifically, the duration of this timer can be configured by the source IAB host node, the target IAB host node, or predefined by the communication protocol. That is, when the IAB node receives the first message, it first starts this timer. After the timer expires, it releases the F1 connection with the CU of the source IAB host node. This allows the IAB node sufficient processing time before releasing the F1 connection, improving the reliability of the F1 connection release.

[0265] It should be understood that the above-described device is used to execute the method for releasing F1 connection on the source IAB host node side in the above embodiments. The implementation principle and technical effect of the corresponding program modules in the device are similar to those described in the method for releasing F1 connection on the source IAB host node side. The working process of the device can be referred to the corresponding process in the method for releasing F1 connection on the source IAB host node side, which will not be repeated here.

[0266] See Figure 21 , Figure 21 This is a schematic diagram of a device for releasing an F1 connection, provided in an embodiment of this application. The device for releasing an F1 connection can be used in an IAB node, which includes IAB-MT and IAB-DU, for example: Figures 9 to 11In any Inter-CU switching scenario, IAB-MT and IAB-DU are used. For example... Figure 21 As shown, the device for releasing the F1 connection may include:

[0267] The receiving module 211 is configured to receive a first message from the source IAB host node, the first message being used to indicate a change in the CU of the IAB host node to which the IAB node is connected.

[0268] Release module 212 is configured to release the F1 connection with the CU of the source IAB host node according to the first message;

[0269] The source IAB host node is the IAB host node that the IAB node was connected to before the CU of the connected IAB host node was changed.

[0270] Specifically, the source IAB host node can refer to the IAB host node that the IAB node was connected to before the CU of the connected IAB host node changed. The IAB node can refer to the switching IAB node or its downstream node. The downstream node of the switching IAB node can include the child node, grandchild node (child of a child node), and great-grandchild node of the switching IAB node. Furthermore, this downstream node can be another IAB node or a UE. As an example, the message name of the first message can implicitly indicate a change in the CU of the IAB host node connected to the IAB node. For example, an F1 RemovalRequest message (an existing F1AP message), or a newly defined message (e.g., an F1 Release Request message).

[0271] In one possible implementation, the first message includes first information, which is used to indicate that the CU of the IAB host node to which the IAB node is connected has changed or a cross-host CU switch has occurred.

[0272] Specifically, the information carried in the first message explicitly or implicitly indicates a change in the CU of the IAB host node to which the IAB node is connected. For example, the first message includes first information used to indicate a change in the CU of the IAB host node to which the IAB node is connected, or a switchover between host CUs. For instance, this first information could be as follows: Figure 12 The instruction information shown is 1.

[0273] In one possible implementation, the first message is an F1AP message.

[0274] Specifically, the F1AP message can be an F1AP message, such as an F1 Removal Request message; or it can be a newly defined F1AP message. Optionally, the F1AP message may carry first information, which is used to indicate that the CU of the IAB host node connected to the IAB node has changed or a cross-host CU switch has occurred. In one possible implementation, the receiving module 211 includes:

[0275] The receiving submodule is configured to receive the first message from the source IAB host node via the target IAB host node;

[0276] Wherein, the target IAB host node is the IAB host node that the IAB node connects to after the CU of the connected IAB host node is changed. For example: Figures 9 to 11 In any Inter-CU switching scenario, IAB donor-CU2 and IABdonor-DU2 are involved. In this application, the source IAB host node sends a first message to the IAB node through the target IAB host node; specifically, the source IAB host node sends the first message to the target IAB donor-DU2 through the target IAB host node. Figures 9 to 11 In any Inter-CU handover scenario, the IAB donor-DU2 sends the first message to the IAB node; that is, the transmission of the first message does not pass through the target IAB donor-CU. Figures 9 to 11 (IAB donor-CU2 in any Inter-CU handover scenario).

[0277] It should be understood that since the source IAB host node can route the first message to the target IAB host node via a wired connection, and the target IAB host node can further route and forward the first message to the IAB node through the target path after receiving the first message, the IAB node can receive the first message from the source IAB host node through the target IAB host node.

[0278] In one possible implementation, the receiving submodule includes:

[0279] The first establishment unit is configured to establish a first TNL association with the source IAB host node based on the IP address allocated to the IAB node by the target IAB host node.

[0280] The first receiving unit is configured to receive the first message from the source IAB host node through the target IAB host node based on the first TNL association.

[0281] Specifically, from the perspective of the IAB node, the IAB node can establish a first TNL association with the source IAB host based on the IP address assigned by the target IAB host. In other words, the first TNL association is triggered by the IAB node and established with the source IAB host node. For a detailed explanation of its implementation, please refer to the newly created TNL in method 1-1 above.

[0282] In one possible implementation, the first message further includes second information, which includes the IP address assigned to the IAB node by the source IAB host node and / or the identifier of the CU of the source IAB host node.

[0283] Specifically, the first message received based on the first TNL association may further include second information. The second information includes the IP address assigned to the IAB node by the source IAB host node and / or the identifier of the CU of the source IAB host node, or the second information includes indication information showing the IAB node deleting the source F1 connection. For example, the second information may be as follows: Figure 13 The instruction information shown is 2.

[0284] In one possible implementation, the receiving submodule includes:

[0285] The second establishment unit is configured to establish a second TNL association with the source IAB host node based on the IP address assigned to the IAB node by the source IAB host node.

[0286] The second receiving unit is configured to receive the first message from the source IAB host node through the target IAB host node based on the second TNL association.

[0287] The second TNL association is triggered by the IAB node and established with the source IAB host node. Its specific implementation process can be found in the old TNL of method 1-2 above. It is worth noting that when an IAB node initially connects to the source IAB host node, before establishing a source F1 connection, the IAB node can establish a second TNL association with the source IAB host node based on the IP address assigned to it by the source IAB host node. When the IAB node performs a handover, the source IAB host node can send a first message to the IAB node through the target IAB host node based on the already established second TNL association.

[0288] In one possible implementation, the first message includes an inner IP header and an outer IP header, wherein the IP address of the IAB node included in the inner IP header corresponds to the source IAB host node, and the IP address of the IAB node included in the outer IP header corresponds to the target IAB host node.

[0289] It should be understood that the inner layer here refers to the second IP encapsulation process, and the outer layer refers to the first IP encapsulation process. Optionally, the IP address of the IAB node included in the inner layer can be the IP address assigned by the target IAB host node, and the IP address of the IAB node included in the outer layer can be the IP address assigned by the source IAB host node. For example, such as... Figure 16 As shown, the F1AP message sent from the source IAB donor-CU to the IAB-DU undergoes two IP encapsulations. Taking the following data transmission as an example, in the first IP encapsulation, the destination IP address is the IP address assigned to the IAB node by the source IAB donor, and the source IP address is the IP address of the source IAB donor-CU. In the second IP encapsulation, the destination IP address is the IP address assigned to the IAB node by the target IAB donor, and the source address is the IP address of the source IAB donor-CU.

[0290] In one possible implementation, the release module 212 includes:

[0291] The startup submodule is configured to start the timer;

[0292] The release submodule is configured to release the F1 connection with the CU of the source IAB host node after the timer expires.

[0293] Specifically, the IAB node can start a timer. When the timer expires, it releases the F1 connection with the CU of the source IAB host node. This allows the IAB node some processing time before releasing the source F1 connection, thereby improving the reliability of releasing the source F1 connection. The duration of this timer can be configured by the source IAB host node, the target IAB host node, or it can be predetermined by the communication protocol.

[0294] In one possible implementation, the first message may also include information about the duration of the timer.

[0295] It should be understood that the IAB node can obtain the timer duration based on the first message, and then start the corresponding timer according to that duration. The F1 connection with the CU of the source IAB host node will be released only after the corresponding timer expires. It should be understood that the above-described device is used to execute the method for releasing the F1 connection on the IAB host side in the above embodiments. The implementation principle and technical effects of the corresponding program modules in the device are similar to those described in the method for releasing the F1 connection on the IAB host side. The working process of this device can be referred to the corresponding process in the above-described method for releasing the F1 connection on the IAB host side, and will not be repeated here.

[0296] See Figure 22 , Figure 22This is a schematic diagram of a communication device provided in an embodiment of this application. The communication device can be an IAB host node (e.g., the source host node or target host node in the embodiments of this application), capable of implementing the functions of the IAB host node in the above method embodiments; or the communication device can be an IAB node, capable of implementing the functions of the IAB node in the above method embodiments. For ease of explanation, Figure 22 The main components of the communication device are shown, such as Figure 22 As shown:

[0297] The communication device includes at least one processor 711, at least one memory 712, at least one transceiver 713, at least one network interface 714, and one or more antennas 715. The processor 711, memory 712, transceiver 713, and network interface 714 are connected, for example, via a bus. In this embodiment, the connection may include various interfaces, transmission lines, or buses, etc., and this embodiment is not limited thereto. The antenna 715 is connected to the transceiver 713. The network interface 714 enables the communication device to connect to other network devices via a communication link.

[0298] The processor 711 is mainly used to process communication protocols and communication data, control the entire node, execute software programs, and process the data of the software programs.

[0299] As an optional implementation, the processor may include a baseband processor and a central processing unit (CPU). The baseband processor is mainly used for processing communication protocols and communication data. The CPU is mainly used for controlling the entire terminal device, executing software programs, and processing the data of the software programs. Alternatively, the processor may integrate the functions of the baseband processor and the CPU. Those skilled in the art will understand that the baseband processor and the CPU can also be independent processors interconnected via technologies such as buses. Those skilled in the art will understand that a node may include multiple baseband processors to adapt to different network standards, and a node may include multiple CPUs to enhance its processing capabilities. The various components of the node can be connected via various buses. The baseband processor can also be described as a baseband processing circuit or a baseband processing chip. The CPU can also be described as a central processing circuit or a central processing chip. The function of processing communication protocols and communication data can be built into the processor or stored in memory as a software program, which is then executed by the processor to implement the baseband processing function.

[0300] The memory 712 is primarily used to store software programs and data. The memory 712 can exist independently and be connected to the processor 711. Optionally, the memory 712 can be integrated with the processor 711, for example, integrated within a single chip, i.e., on-chip memory, or the memory 712 can be a separate storage element; this embodiment does not limit this. The memory 712 can store program code that executes the technical solutions of this embodiment, and its execution is controlled by the processor 711. The various types of computer program code being executed can also be considered as drivers for the processor 711.

[0301] Transceiver 713 can be used for baseband signal to radio frequency (RF) signal conversion and RF signal processing. Transceiver 713 can be connected to antenna 715. Transceiver 713 includes a transmitter (Tx) and a receiver (Rx). Specifically, one or more antennas 715 can receive RF signals. The receiver Rx of transceiver 713 receives the RF signals from the antennas, converts the RF signals into digital baseband signals or digital intermediate frequency (IF) signals, and provides the digital baseband signals or IF signals to processor 711 so that processor 711 can perform further processing on the digital baseband signals or IF signals, such as demodulation and decoding. Furthermore, the transmitter Tx in transceiver 713 receives the modulated digital baseband signals or IF signals from processor 711, converts the modulated digital baseband signals or IF signals into RF signals, and transmits the RF signals through one or more antennas 715. Specifically, the receiver Rx can selectively perform one or more stages of downmixing and analog-to-digital conversion on the radio frequency signal to obtain a digital baseband signal or a digital intermediate frequency (IF) signal. The order of the downmixing and IF conversion is adjustable. The transmitter Tx can selectively perform one or more stages of upmixing and digital-to-analog conversion on the modulated digital baseband signal or digital IF signal to obtain a radio frequency signal. The order of the upmixing and IF conversion is also adjustable. The digital baseband signal and the digital IF signal can be collectively referred to as digital signals. Optionally, the transmitter Tx and the receiver Rx can be implemented using different physical structures / circuits, or they can be implemented using the same physical structure / circuit; that is, the transmitter Tx and the receiver Rx can be integrated.

[0302] A transceiver can also be called a transceiver unit, transceiver, or transceiver device. Optionally, the device in the transceiver unit that performs the receiving function can be considered the receiving unit, and the device in the transceiver unit that performs the transmitting function can be considered the transmitting unit. That is, the transceiver unit includes a receiving unit and a transmitting unit. The receiving unit can also be called a receiver, input port, or receiving circuit, and the transmitting unit can be called a transmitter, transmitter, or transmitting circuit. Alternatively, the combination of Tx, Rx, and antenna can be considered as a transceiver.

[0303] exist Figure 22 In this embodiment, if the communication device is a source IAB host node, the source IAB host node can communicate with the target IAB host node through a network interface, thereby completing the transmission and reception of information and / or messages between the source IAB host node and the target IAB host node. The source IAB host node can communicate with the IAB node through a transceiver and antenna, thereby completing the transmission and reception of information and / or messages between the source IAB host node and the IAB node. If the communication device is an IAB node, the IAB node can communicate with either the source IAB host node or the target IAB host node through a transceiver and antenna, thereby completing the transmission and reception of information and / or messages between the IAB node and the source IAB host node or the target IAB host node. Specific information and / or messages can be found in the above embodiments and will not be repeated here.

[0304] Figure 23 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application. The communication device can be an IAB host node (e.g., the source host node or target host node in this application), and can implement the functions of the IAB host node in the above method embodiments. The communication device can adopt a CU-DU separated architecture. For example... Figure 23 As shown, the communication device may include one or more DU 1101 and one or more CU 1102. DU 1101 may include at least one antenna 11011, at least one radio frequency unit 11012, at least one processor 11013, and at least one memory 11014. The DU 1101 is mainly used for transmitting and receiving radio frequency signals, converting radio frequency signals to baseband signals, and performing some baseband processing. CU 1102 may include at least one processor 11022 and at least one memory 11021. CU 1102 and DU 1101 can communicate via an interface, where the control plane interface can be F1-C and the user plane interface can be F1-U.

[0305] The CU 1102 is mainly used for baseband processing and base station control. The DU 1101 and CU 1102 can be physically installed together or physically separated, i.e., a distributed base station. The CU 1102 is the control center of the base station, also known as a processing unit, and is mainly used to complete baseband processing functions. For example, the CU 1102 can be used to control communication equipment to execute the operation procedures described in the above method embodiments.

[0306] Specifically, the baseband processing on CU and DU can be divided according to the protocol layer of the wireless network, as detailed above.

[0307] In one example, the CU1102 can be composed of one or more single boards. Multiple single boards can collectively support a single access indication wireless access network (such as a 5G network), or they can each support wireless access networks with different access standards (such as LTE, 5G, or other access networks). The memory 11021 and processor 11022 can serve one or more single boards. That is, each single board can have its own memory and processor, or multiple single boards can share the same memory and processor. Furthermore, each single board can also have necessary circuitry. Similarly, the DU1101 can be composed of one or more single boards. Multiple single boards can collectively support a single access indication wireless access network (such as a 5G network), or they can each support wireless access networks with different access standards (such as LTE, 5G, or other access networks). The memory 11014 and processor 11013 can serve one or more single boards. That is, each single board can have its own memory and processor, or multiple single boards can share the same memory and processor. Furthermore, each single board can also have necessary circuitry.

[0308] Optionally, CU 1102 can transmit with IAB nodes via DU 1101. CU 1102 can connect to other communication devices via an interface. CU 1102 can receive data and / or messages from other communication devices (e.g., CUs of other communication devices) through this interface, or CU 1102 can send data and / or messages to the other communication device through this interface.

[0309] For example, if the communication device is the source host node, CU 1102 can send and receive messages and / or information through the interface between it and the target host node, and CU 1102 can send and receive messages and / or information with the IAB node through DU 1101. The specific information and / or messages can be found in the above embodiments and will not be repeated here.

[0310] This application also provides a communication system, including two or more of a source IAB host node, a target IAB host node, and IAB nodes; wherein the source IAB host node can execute a method for releasing F1 connections on the source IAB host node side; and the IAB nodes can execute a method for releasing F1 connections on the IAB node side.

[0311] This application also provides a computer storage medium that includes computer instructions that, when executed on a source IAB host node, enable the source IAB host node to perform a method for releasing an F1 connection on the source IAB host node side.

[0312] This application also provides a computer storage medium that includes computer instructions that, when executed on an IAB node, enable the IAB node to perform a method for releasing an F1 connection on the IAB node side.

[0313] It is understood that the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor.

[0314] The method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can reside in an ASIC.

[0315] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state disk (SSD)).

[0316] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application.

Claims

1. A method for switching between host-centralized units (CUs), characterized in that, The method is used for an integrated access and backhaul, IAB, node, and the method comprises: receiving, by a target IAB donor node, a first message from a source IAB donor node, the first message being used to indicate that a centralized unit, CU, of an IAB donor node to which the IAB node is connected has changed; releasing, according to the first message, an F1 connection between the IAB node and the CU of the source IAB donor node; wherein the source IAB donor node is an IAB donor node to which the IAB node is connected before a CU of the IAB donor node changes, and the target IAB donor node is an IAB donor node to which the IAB node is connected after the CU of the IAB donor node changes.

2. The method of claim 1, wherein, The first message comprises first information used to indicate that the CU of the IAB donor node to which the IAB node is connected changes or a cross-donor CU handover occurs.

3. The method according to claim 1 or 2, characterized in that, The first message is an F1 application layer protocol, F1AP, message.

4. The method of claim 1, wherein, The receiving, by the target IAB donor node, of the first message from the source IAB donor node comprises: establishing, according to an IP address allocated to the IAB node by the target IAB donor node, a first transport network layer, TNL, association with the source IAB donor node; receiving, based on the first TNL association, the first message from the source IAB donor node by the target IAB donor node.

5. The method of claim 4, wherein, The first message further comprises second information, and the second information comprises an internet protocol, IP, address allocated to the IAB node by the source IAB donor node and / or an identifier of the CU of the source IAB donor node.

6. The method of claim 1, wherein, The receiving, by the target IAB donor node, of the first message from the source IAB donor node comprises: establishing, according to an IP address allocated to the IAB node by the source IAB donor node, a second TNL association with the source IAB donor node; receiving, based on the second TNL association, the first message from the source IAB donor node by the target IAB donor node.

7. The method of claim 6, wherein, The first message comprises an inner IP header and an outer IP header, the IP address of the IAB node comprised in the inner IP header corresponds to the target IAB donor node, and the IP address of the IAB node comprised in the outer IP header corresponds to the source IAB donor node.

8. The method of claim 1 or 2, wherein, The releasing, according to the first message, of the F1 connection between the IAB node and the CU of the source IAB donor node comprises: starting a timer; releasing, after the timer expires, the F1 connection between the IAB node and the CU of the source IAB donor node.

9. The method of claim 8, wherein, The first message further comprises information about a time length of the timer. 10.A method for inter-donor central unit (CU) handover, the method comprising: The method is used for a source integrated access and backhaul, IAB, donor node, and the method comprises: determining a first message, the first message being used to indicate that a centralized unit, CU, of an IAB donor node to which an IAB node is connected has changed; sending, by a target IAB donor node, the first message to the IAB node to release an F1 connection between the IAB node and the CU of the source IAB donor node; The source IAB donor node is a connected IAB donor node of the IAB node before the CU of the connected IAB donor node changes; and the target IAB donor node is a connected IAB donor node of the IAB node after the CU of the connected IAB donor node changes.

11. The method of claim 10, wherein, The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs.

12. The method according to claim 10 or 11, characterized in that, The first message is an F1 application layer protocol (F1AP) message.

13. The method of claim 10, wherein, The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs. The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs. The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs.

14. The method of claim 13, wherein, The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs.

15. The method of claim 10, wherein, The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs. The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs. The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs.

16. The method of claim 15, wherein, The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs. The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs. The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs.

17. The method of claim 10, wherein, The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs.

18. The method of claim 10 or 11, wherein, The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs.

19. A device for releasing an F1 connection, characterized in that, The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs. The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs. The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs. The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs. The first message includes first information used to indicate that the CU of the connected IAB donor node of the IAB node changes or switching across the CUs of the donor nodes occurs. 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20. A device for releasing an F1 connection, characterized in that, The apparatus is used for a source integrated access and backhaul, IAB, donor node, and the apparatus includes: A determining module configured to determine a first message, the first message being used to indicate that a CU of a connected IAB donor node of an IAB node has changed; A sending module configured to send, by a target IAB donor node, the first message to the IAB node to release an F1 connection between the CU of the source IAB donor node; The source IAB donor node is a connected IAB donor node of the IAB node before the CU of the connected IAB donor node changes; and the target IAB donor node is a connected IAB donor node of the IAB node after the CU of the connected IAB donor node changes.

21. A communications device, characterized by The communication apparatus includes a processor coupled with a memory; The memory is used to store computer instructions; The processor is used to execute the computer instructions, so that the method in any one of claims 1-9 is executed.

22. A communications device, characterized by The communication apparatus includes a processor coupled with a memory; The memory is used to store computer instructions; The processor is used to execute the computer instructions, so that the method in any one of claims 10-18 is executed.

23. A communication system, characterized by Two or more of the IAB node, the source IAB donor node, and the target IAB donor node are included; wherein the IAB node is used to execute the method in any one of claims 1-9; and the source IAB donor node is used to execute the method in any one of claims 10-18.

24. A computer storage medium, comprising, The computer storage medium includes computer instructions, when the computer instructions are executed, so that the method in any one of claims 1-9 is executed.

25. A computer storage medium, comprising, The computer storage medium includes computer instructions, when the computer instructions are executed, so that the method in any one of claims 10-18 is executed.

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