Method for transmitting and receiving signals, device for transmitting and receiving signals, and communication system

Abstract

Embodiments of the present disclosure provide a method and apparatus for transmitting and receiving signals and a communication system, wherein the apparatus for transmitting and receiving signals is applicable to a first integrated access and backhaul node donor central unit (IAB-donor-CU), the apparatus comprises a first transmitting and receiving unit, the first transmitting and receiving unit being configured to: transmit a traffic offloading request to a second IAB-donor-CU; and receive a response of consent to traffic offloading or a response of refusal to traffic offloading transmitted by the second IAB-donor-CU.

Description

Technology Field

[0001] The present disclosure relates to the field of communication technology. Background Technology

[0002] Integrated access and backhaul (IAB), also referred to as integrated backhaul, enables radio relay functions in next-generation radio access networks (NG-RAN). Integrated access and backhaul nodes (IAB nodes) support access and backhaul via New Radio (NR). The endpoint of NR backhaul on the network side is referred to as an IAB donor, which represents a network device (e.g., a gNB) that supports IAB functions.

[0003] An IAB-node can be connected to an IAB-donor through one or more hops. These multi-hop connections form a directed acyclic graph (DAG) topology with the IAB-donor as the root node. The IAB-donor is responsible for executing centralized resource management, topology management, and routing management in the IAB network topology.

[0004] The IAB-node supports the functions of a gNB-DU (distributed unit), and the IAB-node DU is also referred to as the IAB-DU; it is the endpoint of the NR access (New Radio access) interface to the terminal equipment (UE) and the next-hop IAB-node, and also the endpoint of the F1 protocol to the gNB-CU (central unit) on the IAB-node. The IAB-DU can serve general UEs and IAB child nodes. The IAB-DU enables the functions of network-side devices, connects to downstream child IAB-nodes, provides NR air-interface access to UEs and downstream IAB child nodes, and establishes an F1 connection to the IAB donor-CU.

[0005] In addition to the functions of gNB-DU, the IAB-node also supports some UE functions, referred to as IAB-MT (mobile termination). IAB-MT includes physical layer, layer 2, RRC, and NAS functions that are connected to, for example, another IAB-node or gNB-DU on an IAB-donor, a gNB-CU on an IAB-donor, and the core network. IAB-MT can support functions such as the UE physical layer, access stratum (AS), radio resource control (RRC) layer, and non-access stratum (NAS), and can be connected to an IAB parent node.

[0006] The IAB-donor is an end node on the network side that provides network access to the IAB-MT or UE via backhaul or access links. The IAB-donor is further classified into the IAB-donor-CU (central unit) and IAB-donor-DU. The IAB-DU and IAB-donor-CU are connected via the F1 interface. In an independent networking scenario, the gNB and IAB-donor-CU are connected via the Xn interface.

[0007] To support multi-hop routing forwarding of data packets, a Backhaul Adaptation Protocol (BAP) sublayer is introduced into the IAB. The BAP sublayer is located above the Radio Link Control (RLC) sublayer and below the IP layer, and supports functions such as packet destination node and path selection, packet routing forwarding, bearer mapping, flow control feedback, and notification of backhaul link failures.

[0008] Figure 1 is a schematic diagram of the IAB topology. As illustrated in FIG. 1, in an IAB topology (10), an IAB-node (100) includes an IAB-MT functional unit (101) and an IAB-DU functional unit (102), neighbor nodes connected to the interface of the IAB-DU functional unit (102) are referred to as child nodes such as the child nodes (201, 202 and 203) shown in FIG. 1, and the IAB-DU functional unit (102) can communicate with the child nodes (201, 202 and 203) through an air interface (Uu), neighbor nodes connected to the interface of the IAB-MT functional unit (101) are referred to as parent nodes such as the parent nodes (301 and 302) shown in FIG. 1, and the IAB-MT functional unit (101) can communicate with the parent nodes (301 and 302) through the air interface (Uu).

[0009] As illustrated in FIG. 1, the direction from the IAB-node (100) to the child nodes (201, 202 and 203) is referred to as the downstream direction, and the direction from the IAB-node (100) to the parent nodes (301 and 302) is referred to as the upstream direction. And an IAB-donor (not shown) performs centralized resource management, topology management, and routing management for the IAB topology (10).

[0010] It should be noted that the description of the background art above is provided merely for the purpose of a clear and complete explanation of the present disclosure and for easy understanding by those skilled in the art. Furthermore, the technical solution above should not be understood as being known to those skilled in the art simply because it is described in the background art of the present disclosure.

[0011] Topology redundancy refers to offloading some services from one topology network to another by establishing a redundant path (also known as a second path) for IAB nodes in an IAB topology network, that is, transmitting data through the redundant path. The main purpose of topology redundancy is to balance service loads, reduce service interruptions, and improve network robustness.

[0012] In the existing intra-CU topology redundancy procedure, the establishment and disabling of redundant paths can be performed within an IAB topology under the same IAB-donor-CU, and a certain degree of path diversity and load balancing can be achieved through this procedure. When load saturation is reached in a topology network under the same IAB-donor-CU, the performance of services is affected. Inter-CU topology redundancy can further improve path diversity and better meet the requirements for load balancing.

[0013] However, the inventors found that there is currently no corresponding solution for a method to set or release topology redundant paths between CUs.

[0014] Embodiments of the present disclosure provide a method and apparatus for transmitting and receiving signals and a communication system, wherein a first IAB-donor-CU transmits a traffic offloading request to a second IAB-donor-CU, and the second IAB-donor-CU transmits a response of agreement of traffic offloading or a response of rejection of traffic offloading to the first IAB-donor-CU. Accordingly, redundant paths can be established between the network topology of the first IAB-donor-CU and the network topology of the second IAB-donor-CU, thereby further improving path diversity and better meeting the requirements for load balancing and reduced service interruptions.

[0015] According to aspects of embodiments of the present disclosure, an apparatus for transmitting and receiving signals applicable to a first integrated access and backhaul node donor central unit (IAB-donor-CU) is provided, the apparatus comprises a first transmitting and receiving unit, the first transmitting and receiving unit being:

[0016] Sending a traffic offloading request, i.e., a redundant routing request, to the second IAB-donor-CU;

[0017] It is configured to receive a response of consent to traffic offloading or a response of refusal to traffic offloading transmitted by the second IAB-donor-CU.

[0018] According to another aspect of the embodiments of the present disclosure, an apparatus for transmitting and receiving signals applicable to a second integrated access and backhaul node donor central unit (IAB-donor-CU) is provided, the apparatus comprises a second transmitting and receiving unit, the second transmitting and receiving unit being:

[0019] Receive a traffic offloading request sent by the 1st IAB-donor-CU;

[0020] It is configured to send a response of consent to traffic offloading or a response of refusal to traffic offloading to the first IAB-donor-CU.

[0021] According to additional aspects of embodiments of the present disclosure, an apparatus for transmitting and receiving signals applicable to an IAB-node is provided, wherein the IAB-node is connected to a first parent node, and the IAB-node is already connected to or will be connected to a second parent node, the first parent node is a node in the topology of a first IAB-donor-CU, and the second parent node is a node in the topology of a second IAB-donor-CU.

[0022] The device includes a third transmitting and receiving unit, and the third transmitting and receiving unit is:

[0023] Receive the first RRC reconstruction message transmitted by the first IAB-donor-CU;

[0024] It is configured to send an RRC reconfiguration completion message to the first IAB-donor-CU, and

[0025] The first RRC reconfiguration message is generated in response to the consent for traffic offloading transmitted by the second IAB-donor-CU to the first IAB-donor-CU, and

[0026] The first RRC reconfiguration message includes at least one TNL address assigned to a DU of an IAB-node, and the TNL address is anchored to a second IAB-donor-DU in the topology of a second IAB-donor-CU;

[0027] The RRC reconfiguration complete message is used to indicate that the IAB-node has received the first RRC reconfiguration message.

[0028] According to another aspect of the embodiments of the present disclosure, an apparatus for transmitting and receiving signals applicable to a descendant node of an IAB-node is provided, wherein the IAB-node is connected to a first parent node, and the IAB-node is already connected to or will be connected to a second parent node, the first parent node is a node in the topology of a first IAB-donor-CU, and the second parent node is a node in the topology of a second IAB-donor-CU.

[0029] The device includes a fourth transmitting and receiving unit, and the fourth transmitting and receiving unit is:

[0030] Receive the first RRC reconstruction message transmitted by the first IAB-donor-CU;

[0031] It is configured to send an RRC reconfiguration completion message to the first IAB-donor-CU, and

[0032] The first RRC reconfiguration message is generated in response to the consent for traffic offloading transmitted by the second IAB-donor-CU to the first IAB-donor-CU, and

[0033] The first RRC reconfiguration message includes at least one TNL address assigned to a DU of a descendant node, and the TNL address is anchored to a second IAB-donor-DU in the topology of a second IAB-donor-CU;

[0034] The RRC reconfiguration complete message is used to indicate that a descendant node has received the first RRC reconfiguration message.

[0035] According to another aspect of the embodiments of the present disclosure, a method for transmitting and receiving a signal is provided, corresponding to a device for transmitting and receiving a signal as described in any one of the above aspects.

[0036] An advantage of the embodiments of the present disclosure is that the first IAB-donor-CU transmits a traffic offloading request to the second IAB-donor-CU, and the second IAB-donor-CU transmits a response of consent to traffic offloading or a response of refusal to traffic offloading to the first IAB-donor-CU. Accordingly, a redundant path may be established between the network topology of the first IAB-donor-CU and the network topology of the second IAB-donor-CU.

[0037] Specific embodiments of the present disclosure are disclosed in detail with reference to the following description and drawings, and the principles and modes of use of the present disclosure are indicated. It should be understood that the scope of the embodiments of the present disclosure is not limited thereto. The embodiments of the present disclosure include many changes, modifications, and equivalents within the spirit and scope of the terms of the appended claims.

[0038] The features described and / or exemplified in connection with one embodiment may be used in one or more other embodiments in the same or similar manner and / or combined with or instead of features of other embodiments.

[0039] It should be emphasized that the term “comprising / containing / including,” as used herein, is intended to specify the presence of the mentioned features, integers, steps, or components and does not exclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. Brief explanation of the drawing

[0040] The elements and features described in one drawing or embodiment of the present disclosure may be combined with the elements and features described in one or more additional drawings or embodiments. Additionally, in the drawings, similar reference numbers may designate corresponding parts across several drawings and may be used to designate the same or similar parts in more than one embodiment. Figure 1 is a schematic diagram of the IAB topology. Figure 2 illustrates an example of a topology transmission path in a scenario of inter-CU topology redundancy. FIG. 3 is a schematic diagram of a method for transmitting and receiving a signal of an embodiment of the first aspect. FIG. 4 is a schematic diagram of a method for transmitting and receiving a signal of an embodiment of the second aspect. Figure 5 is a schematic diagram of the procedure for setting the second path of the IAB-node in Example 1. FIG. 6 is a schematic diagram of a method for establishing a CU-to-CU redundant path for the descendant nodes of an IAB-node in Example 2. Figure 7 illustrates a schematic diagram of adding an SN to an IAB-node to change it into a dual-connected node and establishing a redundant path. Figure 8 is a schematic diagram of the success of the traffic offloading procedure. Figure 9 is a schematic diagram of the failure of the traffic offloading procedure. FIG. 10 is a schematic diagram proposing redundant path release by an initiator of traffic offloading. Figure 11 is a schematic diagram proposing redundant path release by a traffic offloading receptor. FIG. 12 is a schematic diagram of a method for transmitting and receiving a signal of an embodiment of a third aspect. FIG. 13 is a schematic diagram of a method for transmitting and receiving a signal of an embodiment of a third aspect. FIG. 14 is a schematic diagram of a device for transmitting and receiving signals of an embodiment of the present disclosure. FIG. 15 is a schematic diagram of a device for transmitting and receiving signals of an embodiment of the sixth aspect. FIG. 16 is a schematic diagram of a device for transmitting and receiving signals of an embodiment of the seventh aspect. FIG. 17 is a schematic diagram of a device for transmitting and receiving signals of an embodiment of the eighth aspect. FIG. 18 is a schematic diagram of the structure of a network device of an embodiment of the present disclosure. FIG. 19 is a schematic diagram of a terminal device of an embodiment of the present disclosure. Specific details for implementing the invention

[0041] These and additional aspects and features of the present disclosure will become apparent from the following description and the accompanying drawings. In the description and drawings, specific embodiments of the present disclosure are disclosed in detail to represent some of the ways in which the principles of the present disclosure may be utilized, but it will be understood that the scope of the present disclosure is not limited accordingly. Rather, the present disclosure includes all changes, modifications, and equivalents within the spirit and terms of the appended claims.

[0042] In the embodiments of the present disclosure, terms such as “first” and “second” are used to distinguish different elements in relation to names and do not indicate a spatial arrangement or chronological order of such elements, and such elements should not be limited by such terms. The term “and / or” includes any one or more appropriately enumerated terms and all combinations thereof. The terms “include,” “comprehensively,” and “have” refer to the presence of the mentioned features, elements, components, or assemblies, but do not exclude the presence or addition of one or more other features, elements, components, or assemblies.

[0043] In the embodiments of the present disclosure, single forms “a” and “the,” etc. include plural forms and should be understood in a broad sense as “one kind” or “one type” and should not be defined as having the meaning of “one”; the term “the,” except otherwise specified, should be understood as including both single and plural forms. Also, except otherwise specified, the term “according to” should be understood as “at least partially according to” and the term “based on” should be understood as “at least partially based on”.

[0044] In embodiments of the present disclosure, the term “communication network” or “wireless communication network” may refer to a network that meets any one of the following communication standards: Long Term Evolution (LTE), Long Term Evolution-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), and High-Speed ​​Packet Access (HSPA), etc.

[0045] And communication between devices within a communication system may be performed according to communication protocols at any stage, which may include, but are not limited to, the following communication protocols: 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G, and future 5G and NR (New Radio), etc., and / or other communication protocols currently known or to be developed in the future.

[0046] In embodiments of the present disclosure, for example, the term “network device” refers to a device within a communication system that accesses user equipment to a communication network and provides services to user equipment. A network device may include, but is not limited to, the following devices: nodes and / or donors in an IAB architecture, a base station (BS), an access point (AP), a transmission reception point (TRP), a broadcast transmitter, a mobile management entity (MME), a gateway, a server, a radio network controller (RNC), and a base station controller (BSC).

[0047] A base station may include, but is not limited to, a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), and a 5G base station (gNB). Additionally, it may include a remote radio head (RRH), a remote radio unit (RRU), a relay, or a low-power node (e.g., femto and pico). The term "base station" may include some or all of its functions, and each base station may provide communication coverage for a specific geographic area. And the term "cell" may refer to a base station and / or its coverage area, depending on the context of the term.

[0048] In the embodiments of the present disclosure, the terms “user equipment (UE)” or “terminal equipment (TE) or terminal device” refer to equipment that accesses a communication network and receives network services through a network device, for example. Terminal equipment may be fixed or mobile and may also be referred to as a mobile station (MS), terminal, subscriber station (SS), access terminal (AT), and station, etc.

[0049] Terminal equipment may include, but is not limited to, the following devices: cellular phones, personal digital assistants (PDAs), wireless modems, wireless communication devices, handheld devices, machine-type communication devices, laptops, cordless phones, smart cell phones, smartwatches, and digital cameras.

[0050] As another example, in scenarios such as the Internet of Things (IoT), user equipment may also be a machine or device that performs monitoring or measurement. For example, it may include, but is not limited to, machine-type communication (MTC) terminals, vehicle-mounted communication terminals, device-to-device (D2D) terminals, and machine-to-machine (M2M) terminals.

[0051] Additionally, the terms "network side" or "network device side" refer to a side of the network that may be a base station or one or more network devices including those described above. The terms "user side" or "terminal side" or "terminal equipment side" refer to a side of a terminal or user that may be a UE and may include one or more terminal equipment described above.

[0052] In embodiments of the present disclosure, the higher-layer signaling may be, for example, radio resource control (RRC) signaling; for example, referred to as an RRC message including an MIB, system information, and a dedicated RRC message; or referred to as an RRC information element (RRC IE). The higher-layer signaling may also be, for example, F1-C signaling or the F1AP protocol; but the present disclosure is not limited thereto.

[0053] In embodiments of the present disclosure, a plurality of UEs are connected to an IAB-donor through multi-hop IAB-nodes and are finally connected to a network, which is, for example, a 5G network.

[0054] Figure 2 illustrates an example of a topology transmission path in a scenario of topology overlap between CUs. In Figure 2, Donor-CU 1 is also referred to as IAB-donor-CU 1, and Donor-CU 2 is also referred to as IAB-donor-CU 2.

[0055] As shown in FIG. 2, Donor-CU 1 is the F1 terminating donor of IAB-Node 3 and IAB-Node 4. IAB-Node 3 is a duplex node and has two paths to Donor-CU 1. IAB-Node 4 may also have two paths to Donor-CU 1. Taking IAB-Node 4 as an example acting as an access IAB-Node, some data between IAB-Node 4 and Donor-CU 1 is transmitted through a topology network controlled by Donor-CU 1 (referred to as the first path, as shown by the solid arrow), and some data is transmitted through a topology network controlled by Donor-CU 2 (referred to as the second path, as shown by the dashed arrow), thereby achieving the goals of data diversion and load balancing. Similarly, IAB-Node 3 and other descendant nodes of IAB-Node 3 (not shown in the drawing) can also serve as access IAB-Nodes for establishing second paths.

[0056] In FIG. 2, IAB-Node 1 is the first parent node of IAB-Node 3, IAB-Node 2 is the second parent node of IAB-Node 3, and IAB-Node 4 is the descendant node of IAB-Node 3. For simplification, the UE under IAB-Node 4 is not shown in the figure.

[0057] In various embodiments of the present disclosure, the first IAB-donor-CU may be Donor-CU 1 of FIG. 2, the second IAB-donor-CU may be Donor-CU 2 of FIG. 2, the IAB-node may be IAB-node 3 of FIG. 2, the descendant node of IAB-node 3 may be IAB-node 4 of FIG. 2, the first parent node of IAB-node 3 may be IAB-node 1 of FIG. 2, the second parent node of IAB-node 3 may be IAB-node 2 of FIG. 2, the first parent node of IAB-node 3 (same as IAB-node 1) is a node in the topology of the first IAB-donor-CU, the second parent node of IAB-node 3 (same as IAB-node 2) is a node in the topology of the second IAB-donor-CU, and the second IAB-donor-DU may be donor-DU 2 of Fig. 2.

[0058] In FIG. 2, when both the first path and the second path are established, IAB-node 3 is connected to a first parent node (such as IAB-node 1), and IAB-node 3 is connected to a second parent node (such as IAB-node 2). Additionally, before the second path is established (i.e., before the method for transmitting and receiving signals in the present disclosure is executed), IAB-node 3 and the second parent node (e.g., IAB-node 2) may be in a connected state or an unconnected state (i.e., to be connected).

[0059] In embodiments of the present disclosure, the access IAB-node includes an IAB-node (e.g., IAB-node 3 in FIG. 2) and / or a descendant node of the IAB-node (e.g., IAB-node 4 in FIG. 2), or an IAB-node that will soon become a dual-connected node (e.g., a node that will soon be connected to the first IAB-donor-CU and the second IAB-donor-CU).

[0060] In embodiments of the present disclosure, IAB-DU may represent a distributed unit of an IAB-node, i.e., the DU of the IAB, and IAB-MT may represent a mobile terminal of an IAB-node, i.e., the MT of the IAB.

[0061] In the embodiments of the present disclosure, a node in the topology of the donor-CU refers to the fact that the DU portion of the node is managed by the donor-CU, that is, the F1 interface of the node is terminated at the donor-CU.

[0062] In various embodiments of the present disclosure, the meanings of donor-CU and IAB-donor-CU are identical and may be interchangeable.

[0063] Example of the first aspect

[0064] An embodiment of the first aspect of the present disclosure provides a method for transmitting and receiving signals applicable to a first integrated access and backhaul node donor central unit (IAB-donor-CU). The method for transmitting and receiving signals will be described from the side of the first IAB-donor-CU in an embodiment of the first aspect of the present disclosure, and the first IAB-donor-CU may be, for example, donor-CU 1 of FIG. 2.

[0065] FIG. 3 is a schematic diagram of a method for transmitting and receiving a signal of an embodiment of a first aspect. As illustrated in FIG. 3, the method comprises the following:

[0066] Operation 301: A traffic offloading request is sent to the 2nd IAB-donor-CU;

[0067] Operation 302: A response of consent to traffic offloading or a response of refusal to traffic offloading transmitted by the second IAB-donor-CU is received.

[0068] In the present disclosure, operations 301 and 302 can support topology redundancy between the first IAB-donor-CU and the second IAB-donor-CU, thereby further improving path diversity and better meeting the requirements for load balancing.

[0069] In at least one embodiment, the traffic offloading request transmitted in operation 301 includes a request to establish cross-donor redundant paths for the IAB-node and / or the descendants of the IAB-node.

[0070] For example, the first IAB-donor-CU configures a backhaul radio link control (BH RLC) channel and routing entries of the BAP sublayer between the IAB-node and its descendant node to support the routing of the second path and the mapping of the BH RLC channel of the second path, thereby establishing a redundant path for the descendant node; additionally, the first IAB-donor-CU can perform the configuration of a BAP routing identification mapping for the IAB-node in response to consent to traffic offloading. Accordingly, at the IAB-node, a BAP routing transformation can be performed between the topology of the first path controlled by the first IAB-donor-CU and the topology of the second path controlled by the second IAB-donor-CU, thereby establishing a redundant path for the descendant node; Additionally, the first IAB-donor-CU can migrate the F1-U path between the first IAB-donor-CU and the DU of the IAB-node and / or the descendant node of the IAB-node from the first path to the second path through a UE context modification request message or a UE context setup request message, thereby establishing duplicate paths for the IAB-node and / or descendant node.

[0071] In at least one embodiment, the response to the consent of traffic offloading in operation 302 may indicate that the traffic offloading request is at least partially accepted, and that the traffic offloading request is at least partially accepted refers to that redundant paths are established for some TNL-associated F1-Cs or for some F1-U tunnels.

[0072] In at least one embodiment, where the IAB-node is connected to a first parent node and the IAB-node is also connected to a second parent node, the traffic offloading request may be included in a traffic offloading request message, and the traffic offloading request message is, for example, a TRAFFIC OFFLOAD REQUEST message or a Redundant Path Establishment Request message; the response to consent to traffic offloading may be included in a traffic offloading request acknowledgment message, such as a TRAFFIC OFFLOAD REQUEST ACKNOWLEDGE message; and the response to refuse traffic offloading may be included in a traffic offloading refusal message, such as a TRAFFIC OFFLOAD REQUEST REJECT message.

[0073] In one implementation, a traffic offloading request message may include an identifier (UE XnAP ID) of the user equipment of the traffic offloading initiator node on the Xn interface, and / or identification information of one or more F1-Cs. The traffic offloading initiator node refers to the first IAB-donor-CU, the user equipment refers to the access IAB-node (the IAB-node acts as the user equipment of the IAB-donor), and the identification information of one or more F1-Cs is used to establish redundant paths for one or more F1-Cs of the access IAB-node.

[0074] In another implementation, the traffic offloading request message includes at least one of the following information: an identifier of the user equipment of the traffic offloading initiation node on the Xn interface (UE XnAP ID), the BAP address of the access IAB-node, the TNL address, one or more F1-U tunnel identification information, IP header information of F1-C and / or F1-U tunnels, and QoS information of the F1-U tunnels.

[0075] In the two implementations above, when traffic offloading requests for at least some of the F1-Cs and / or F1-U tunnels are accepted, the traffic offloading request acceptance message may include at least one of the following information:

[0076] UE XnAP ID of the traffic offloading initiation node, UE XnAP ID of the traffic offloading acceptance node, identification information of the F1-C and / or F1-U tunnel, newly assigned TNL address for the DU of the access IAB-node, BH RLC channel identifier on the link between the dual-link IAB-node configured for the F1-C and / or F1-U tunnel and the second parent node, BAP address of the second parent node, BAP routing identifier in the topology controlled by the second IAB-donor-CU, or the second BAP address of the IAB-node. The traffic offloading acceptance node refers to the second IAB-donor-CU, and the UE XnAP ID of the traffic offloading acceptance node refers to the Xn interface identifier of the access IAB-node within the node of the second IAB-donor-CU. Depending on whether the traffic initiation node and the traffic acceptance node correspond to an MN or an SN, the UE XnAP ID of the traffic offloading initiation node and the UE XnAP ID of the traffic offloading acceptance node may also be referred to as the M-NG-RAN node UE XnAP ID (UE XnAP ID of the main base station node) or the S-NG-RAN node UE XnAP ID (UE XnAP ID of the secondary base station node), respectively.

[0077] In the two implementations above, when traffic offloading requests for all F1-C and F1-U tunnels are rejected, the second IAB-donor-CU sends a traffic offloading request reject message, and the traffic offloading request reject message includes the UE XnAP ID of the traffic offloading initiator node.

[0078] In at least one embodiment, where the IAB-node is connected to a first parent node and the IAB-node is also connected to a second parent node, if the first IAB-donor-CU is a master node (MN), the contents of a traffic offloading request and the contents of a response agreeing to traffic offloading or a response rejecting traffic offloading are taken as information elements (IE) and included in the messages of the XnAP S-NG-RAN node modification preparation procedure.

[0079] In at least one other embodiment, where the IAB-node is connected to the first parent node and the IAB-node is not connected to the second parent node, the contents of the traffic offloading request and the contents of the response agreeing to traffic offloading or the contents of the response rejecting traffic offloading are taken as information elements (IE) and included in the message of the XnAP S-NG-RAN node addition preparation process.

[0080] For example, a traffic offloading request may be included in an auxiliary node addition request (S-NODE ADDITION REQUEST) message sent by the first IAB-donor-CU to the second IAB-donor-CU. For example, a response agreeing to traffic offloading may be included in an auxiliary node addition request acknowledgment (S-NODE ADDITION REQUEST ACKNOWLEDGE) message sent by the second IAB-donor-CU to the first IAB-donor-CU.

[0081] As illustrated in FIG. 3, this method further comprises the following:

[0082] Operation 303: In response to consent to traffic offloading, a first RRC reconfiguration message is sent to the IAB-node and / or the descendant IAB-nodes of the IAB-node.

[0083] In operation 303, the first RRC reconstruction message may include at least one transport network layer (TNL, or transport layer) address assigned to the DU of the IAB-node (e.g., IAB-node 3 in FIG. 2) and / or the DU of the descendant node of the IAB-node (e.g., IAB-node 4 in FIG. 2), respectively, and the TNL address is anchored to the second IAB-donor-DU in the topology of the second IAB-donor-CU (e.g., donor-DU 2 in FIG. 2).

[0084] In operation 303, the BAP configuration information element (bap-Config IE) of the first RRC reconfiguration message includes a field used to indicate a second BAP address configured for an IAB-node—this field is, for example, bap-Address-redundant or bap-Address-second, etc., used to indicate that it is a second BAP address; or the BAP address field within the BAP configuration information element (bap-Config IE) of the first RRC reconfiguration message includes a list, and each entry in the list is a BAP address and its associated information. For example, the list may be bap-AddressList, and each entry in the list is a BAP address and its associated information, and each entry is, for example, {bap-Address, 'MCG' / 'SCG'}, or {bap-Address, iab-donor-DU-BAP-Address}, etc. Therefore, a second BAP address can be assigned to IAB-node 3, and the second BAP address can be used for BAP routing configuration on a redundant path (i.e., a second path passing through donor-DU 2).

[0085] In at least one embodiment, when a new TNL address is assigned to an IAB-node and / or its descendant in operation 303, the first IAB-donor-CU may add the new TNL address to the F1-C association between the DU of the IAB-node and / or its descendant and the first IAB-donor-CU.

[0086] As illustrated in FIG. 3, the method for transmitting and receiving a signal may further include the following:

[0087] Operation 304: The first IAB-donor-CU sends or receives a duplicate path release request;

[0088] Operation 305: The first IAB-donor-CU receives or sends a message accepting a duplicate path release request.

[0089] For example, the first IAB-donor-CU sends a duplicate path release request to the second IAB-donor-CU, and the first IAB-donor-CU receives a duplicate path release request acceptance message from the second IAB-donor-CU; as another example, the first IAB-donor-CU receives the duplicate path release request sent by the second IAB-donor-CU, and the first IAB-donor-CU sends a duplicate path release request acceptance message to the second IAB-donor-CU.

[0090] In at least one embodiment, the redundant path release request includes the UE XnAP ID of the traffic offloading initiation node, the UE XnAP ID of the traffic offloading acceptance node, and the TNL address associated with F1-C that needs to be released from the redundant path, or User Plane Transport Layer Information (UP Transport Layer Information) of the F1-U tunnel that needs to be released from the redundant path, and the redundant path is, for example, the second path shown in FIG. 2.

[0091] In at least one embodiment, when master modes (MNs) in the first IAB-donor-CU and the second IAB-donor-CU transmit duplicate path release requests, the contents of the duplicate path release requests and the contents of the duplicate path release request acceptance messages are taken as IEs and included in the S-NG-RAN node modification preparation procedure.

[0092] In at least one embodiment, when performing the auxiliary base station node release (S-NG-RAN node Release) process of the IAB-node, all redundant paths related to the IAB-node in the SN topology are released.

[0093] According to an embodiment of the first aspect of the present disclosure, the configuration of a redundant path between a first IAB-donor-CU and a second IAB-donor-CU can be supported, thereby further improving path diversity and better meeting the requirements for load balancing and reduced service interruptions. Additionally, the topology redundant path between the first IAB-donor-CU and the second IAB-donor-CU can be disabled.

[0094] Example of the second aspect

[0095] At least in response to the same problem as in the embodiment of the first embodiment, an embodiment of the second embodiment of the present disclosure provides a method for transmitting and receiving a signal corresponding to the method of the embodiment of the first embodiment. The method for transmitting and receiving a signal of the embodiment of the second embodiment is applicable to a second integrated access and backhaul node donor central unit (IAB-donor-CU). The method for transmitting and receiving a signal will be described from the side of the second IAB-donor-CU in the embodiment of the second embodiment of the present disclosure, and the second IAB-donor-CU may be, for example, donor-CU 2 of FIG. 2.

[0096] FIG. 4 is a schematic diagram of a method for transmitting and receiving a signal of an embodiment of a second aspect. As illustrated in FIG. 4, the method comprises the following:

[0097] Operation 401: A traffic offloading request transmitted by the 1st IAB-donor-CU is received;

[0098] Operation 402: A response of consent to traffic offloading or a response of refusal to traffic offloading is transmitted to the first IAB-donor-CU.

[0099] In the present disclosure, operations 401 and 402 can support topology redundancy between the first IAB-donor-CU and the second IAB-donor-CU, thereby further improving path diversity and better meeting the requirements for load balancing.

[0100] In at least one embodiment, the traffic offloading request in operation 401 includes a request to set up redundant paths for an IAB-node (e.g., IAB-node 3 in FIG. 2) and / or a descendant node of the IAB-node (e.g., IAB-node 4 in FIG. 2).

[0101] The response to the consent to traffic offloading in operation 402 indicates that the traffic offloading request is at least partially accepted, and that the traffic offloading request is at least partially accepted indicates that redundant paths are established for some TNL-associated F1-Cs or some F1-U tunnels.

[0102] When an IAB-node is connected to a first parent node and an IAB-node is connected to a second parent node, a traffic offloading request may be included in a traffic offloading request message, and a response agreeing to traffic offloading may be included in a traffic offloading request acknowledgment message, and the traffic offloading request acknowledgment message is, for example, a TRAFFIC OFFLOAD REQUEST ACKNOWLEDGE message, and a response rejecting traffic offloading may be included in a traffic offloading rejection message, and the traffic offloading rejection message is, for example, a TRAFFIC OFFLOAD REQUEST REJECT.

[0103] The traffic offloading request message may include the identifier of the user equipment of the traffic offloading initiation node on the Xn interface (UE XnAP ID), and / or identification information of one or more F1-Cs. The identification information of one or more F1-Cs is used to establish redundant paths for one or more F1-Cs of the access IAB-node, and the access IAB-node includes an IAB-node and / or a descendant node of the IAB-node, or an IAB-node that will soon become a dual-connected node.

[0104] The traffic offloading request message may include at least one of: the UE XnAP ID of the traffic offloading initiating node, the BAP address of the access IAB-node, the TNL address, one or more F1-U tunnel identification information, the IP header information of the F1-C and / or F1-U tunnels, or the QoS information of the F1-U tunnels.

[0105] In at least one embodiment, when a traffic offloading request for the F1-C and / or F1-U tunnel is accepted, the traffic offloading request acknowledgment message is:

[0106] It may include at least one of the UE XnAP ID of the traffic offloading initiation node, the UE XnAP ID of the traffic offloading acceptance node, identification information of the F1-C and / or F1-U tunnel, a newly assigned TNL address for the DU of the access IAB-node, a BH RLC channel identifier on the link between the dual-link IAB-node and the second parent node configured for the F1-C and / or F1-U tunnel, the BAP address of the second parent node, a BAP routing identifier in the topology controlled by the second IAB-donor-CU, or the second BAP address of the IAB-node, and the traffic offloading acceptance node refers to the second IAB-donor-CU, and the UE XnAP ID of the traffic offloading acceptance node refers to the Xn interface identifier of the access IAB-node within the node of the second IAB-donor-CU.

[0107] Additionally, if traffic offloading requests for all F1-C and F1-U tunnels are denied, the second IAB-donor-CU may send a traffic offloading request denial message to the first IAB-donor-CU, and the traffic offloading request denial message includes the UE XnAP ID of the traffic offloading initiation node.

[0108] In at least one embodiment, where the IAB-node is connected to a first parent node and the IAB-node is connected to a second parent node, if the first IAB-donor-CU is a master node (MN), the contents of a traffic offloading request and the contents of a response agreeing to traffic offloading or a response rejecting traffic offloading are taken as information elements (IE) and included in the messages of the XnAP S-NG-RAN node modification preparation procedure.

[0109] In at least one embodiment, where the IAB-node is connected to the first parent node and the IAB-node is not connected to the second parent node, the contents of the traffic offloading request and the contents of the response agreeing to traffic offloading or the contents of the response rejecting traffic offloading are taken as information elements (IE) and included in the message of the XnAP S-NG-RAN node addition preparation process.

[0110] For example, a traffic offloading request is included in an auxiliary node addition request (S-NODE ADDITION REQUEST) message sent by the first IAB-donor-CU to the second IAB-donor-CU. As another example, a response agreeing to traffic offloading is included in an auxiliary node addition request acknowledgment (S-NODE ADDITION REQUEST ACKNOWLEDGE) message sent by the second IAB-donor-CU to the first IAB-donor-CU.

[0111] As illustrated in FIG. 4, this method further comprises the following:

[0112] Operation 403: When the IAB-node is already connected to the second parent node, the second IAB-donor-CU sends a UE context modification request message to the second parent node to modify the User Equipment (UE) context of the IAB-node's Mobile Terminal (MT), and establishes at least one bearer; or

[0113] Operation 404: When the IAB-node is not connected to the second parent node, the second IAB-donor-CU sends a UE context setup request message to the second parent node to set up the UE context of the IAB's MT and sets up at least one bearer.

[0114] As illustrated in FIG. 4, this method further comprises the following:

[0115] Operation 405: For a second path required by an IAB-node and / or a descendant node of the IAB-node, the second IAB-donor-CU performs the configuration of a BH RLC channel between the IAB-node and the second IAB-donor-DU and the configuration of a BAP sublayer routing entry.

[0116] As illustrated in FIG. 4, this method further comprises the following:

[0117] Operation 406: The second IAB-donor-CU transmits the address of the second BAP configured for the IAB-node to the mobile terminal (MT) of the IAB-node.

[0118] In operation 406, the second IAB-donor-CU may transmit a second reconfiguration (RRCReconfiguration) message to the mobile terminal (MT) of the IAB-node, and the second RRCReconfiguration message includes BAP configuration information (bap-Config), and the BAP configuration information includes the address of the second BAP configured for the IAB-node.

[0119] In the present disclosure, a second path may be configured for the IAB-node in operations 403-403.

[0120] As illustrated in FIG. 4, this method further comprises the following:

[0121] Operation 407: The 2nd IAB-donor-CU receives or sends a duplicate path release request;

[0122] Operation 408: The second IAB-donor-CU sends or receives a message accepting a duplicate path release request.

[0123] For example, in operation 407, the second IAB-donor-CU receives a duplicate path release request sent by the first IAB-donor-CU, and in operation 408, the second IAB-donor-CU sends a duplicate path release request acceptance message to the first IAB-donor-CU. As another example, in operation 407, the second IAB-donor-CU sends a duplicate path release request to the first IAB-donor-CU, and in operation 408, the second IAB-donor-CU receives a duplicate path release request acceptance message sent by the first IAB-donor-CU.

[0124] In at least one embodiment, the redundant path release request in operation 407 comprises: the UE XnAP ID of the traffic offloading initiation node, the UE XnAP ID of the traffic offloading acceptance node, and the TNL address associated with F1-C that needs to be released from the redundant path, or User Plane Transport Layer Information (UP Transport Layer Information) of the F1-U tunnel that needs to be released from the redundant path, and the redundant path is the second path shown in FIG. 2.

[0125] When MNs in the first IAB-donor-CU and the second IAB-donor-CU transmit duplicate path release requests, the contents of the duplicate path release requests and the contents of the duplicate path release request acceptance messages are taken as IEs and included in the S-NG-RAN node modification preparation procedure.

[0126] When performing the auxiliary base station node release (S-NG-RAN node Release) process of the IAB-node, all redundant paths associated with the IAB-node in the SN topology (e.g., IAB-node 3 shown in Fig. 2) are released.

[0127] According to an embodiment of the second aspect of the present disclosure, the establishment of a topology redundant path between the first IAB-donor-CU and the second IAB-donor-CU can be supported, thereby further improving the diversity of paths and better satisfying the requirements for load balancing; additionally, the topology redundant path between the first IAB-donor-CU and the second IAB-donor-CU can be released.

[0128] A method for transmitting and receiving a signal in an embodiment of the first aspect and a method for transmitting and receiving a signal in an embodiment of the second aspect will be described in detail with reference to specific embodiments.

[0129] Example 1

[0130] In Example 1, the IAB-node (e.g., IAB-node 3 shown in FIG. 2) is in a state where it is already double-connected to two different IAB-donor-CUs. Therefore, in Example 1, IAB-node 3 is also referred to as a double-connected IAB-node.

[0131] Since the F1 interface can be established after the MT of the IAB-node is connected to two different donors, the F1 end node may be an MN or an SN. On the first path, the first IAB-donor-CU (e.g., IAB-donor-CU 1 in FIG. 2) is an F1-end node that may be a master node (MN) or an auxiliary node (SN) in this embodiment. On the second path, the second IAB-donor-CU (e.g., IAB-donor-CU 2 in FIG. 2) is a non-F1-end node that may be an SN or an MN in this embodiment.

[0132] FIG. 5 is a schematic diagram of the procedure for establishing the second path of the IAB-node in Example 1. As illustrated in FIG. 5, the establishment procedure includes the following steps:

[0133] 1. IAB-donor-CU 1 initiates a traffic offloading request to IAB-donor-CU 2 (e.g., a TRAFFIC OFFLOAD REQUEST), that is, a request to establish a redundant path for a duplex IAB-node. If IAB-donor-CU 2 rejects it, IAB-donor-CU 2 directly transmits a response rejecting the traffic offloading, and subsequent steps are not executed.

[0134] 2. If IAB-donor-CU 2 agrees to or partially agrees to the traffic offloading request, IAB-donor-CU 2 sends a UE CONTENT MODIFICATION REQUEST message to the IAB-DU of the second parent node of the dual-link IAB-node to modify the UE context of the dual-link IAB-MT and establishes one or more bearers.

[0135] 3. The IAB-DU of the second parent node of the dual-linked IAB-node sends a UE CONTENT MODIFICATION RESPONSE message to the IAB-donor CU 2.

[0136] 4. If it is necessary to assign a second BAP address to a dual-link IAB-node, the IAB-donor CU 2 transmits a downlink wireless link control message transmission (e.g., DL RRC MESSAGE TRANSFER) message to the IAB-DU of the second parent node, and this message includes a generated RRCReconfiguration message, and the RRCReconfiguration message includes a bap-Config containing the configured second BAP address.

[0137] 5. The second parent node forwards the received RRCReconfiguration message to the duplex IAB-MT.

[0138] 6. The dual-linked IAB-MT sends a response to the second parent node with an RRC ReconfigurationComplete message.

[0139] 7. The second parent node sends a response to IAB-donor-CU 2 with an uplink wireless link control transfer (UL RRC MESSAGE TRANSFER) message, which includes the received RRCReconfigurationComplete message.

[0140] 8. IAB-donor-CU 2 performs BH RLC channel configuration and BAP sublayer routing entry configuration between the dual-linked IAB-node and IAB-donor-DU 2 on the second path (configuration of BAP routes and mapping rules following the second path between the dual-linked IAB-node and the second path IAB-donor-DU through the second parent IAB-node). Step 8 may be executed earlier, such as immediately after Step 2.

[0141] 9. IAB-donor-CU 2 sends a response to IAB-donor-CU 1 with consent for traffic offloading.

[0142] 10. IAB-donor-CU 1 transmits a DL RRC MESSAGE TRANSFER message to the IAB-DU of the first parent node according to the content of the response from IAB-donor-CU 2 (e.g., assigned TNL address), and this message includes a generated RRCReconfiguration message. The RRCReconfiguration message may include one or more TNL addresses assigned to the dual-linked IAB-DU, and these addresses are anchored to the IAB-donor-DU of the second path (e.g., donor-DU 2 in FIG. 2). IAB-donor-CU 2 may obtain these TNL addresses in advance from donor-DU 2. When the IPsec channel mode is used to protect F1 and non-F1 traffic, the assigned TNL addresses are outer IP addresses. If a redundant path has previously been established for F1-C or F1-U of a dual-connected IAB-node, the assigned TNL addresses may no longer need to be assigned.

[0143] 11. The first parent node forwards the received RRCReconfiguration message to the duplex IAB-MT.

[0144] 12. The dual-linked IAB-MT sends a response to the second parent node with an RRCReconfigurationComplete message.

[0145] 13. The first parent node sends a UL RRC MESSAGE TRANSFER message to IAB-donor-CU 2, and this message conveys the received RRCReconfigurationComplete message.

[0146] 15. When new TNL address(s) are assigned in Step 10, the addition of the new TNL address(s) to the F1-C associations of the dual-linked IAB-node DU is performed. IAB-donor-CU 1 can configure new UL BH information for F1AP messages of the second path, and, for example, a specific procedure can be achieved through the gNB DU configuration update procedure of the F1AP.

[0147] 16. IAB-donor-CU 1 migrates the F1-U tunnel between IAB-donor-CU 1 and the duplex IAB-DU from the first path to the second path via the UE CONTEXT MODIFICATION REQUEST message.

[0148] 17. The dual-connection IAB-DU sends a response with a CONTEXT MODIFICATION RESPONSE message.

[0149] Accordingly, a second path of the dual-connection IAB-node can be established, and uplink user data or downlink user data can be transmitted between the user equipment (UE) and the first IAB-donor-CU through the second path.

[0150] For example, as illustrated in FIG. 5, the transmission order of uplink user data on the second path is: UE--duplex IAB-node--second parent node--intermediate hop IAB-node on the second path--donor-DU on the second path (e.g., donor-DU 2 in FIG. 2)--first IAB-donor-CU.

[0151] As another example, as illustrated in FIG. 5, the transmission order of downstream user data on the second path is as follows: first IAB-donor-CU--donor-DU on the second path (e.g., donor-DU 2 in FIG. 2)--intermediate hop IAB-node on the second path--second parent node--duplex IAB-node--UE.

[0152] In Example 1, a second BAP address is assigned to the dual-linked IAB-node in steps 4-7. The second BAP address can be used for BAP routing configuration on the redundant path (i.e., the second path). The dual-linked IAB-node needs to associate the BAP address with a Master Cell Group (MCG) / Secondary Cell Group (SCG) or an MN / SN. If an RRCReconfiguration message with a BAP address received by the dual-linked node is from the MCG or received via SRB1 (signaling radio bearer 1), the received BAP address is associated with the MCG or MN; if an RRCReconfiguration message with a BAP address received by the dual-linked node is from the SCG or received via SRB3, the received BAP address is associated with the SCG or SN.

[0153] Additionally, the second BAP address may be assigned in other ways as well. For example, steps 4-7 may be removed, and the second BAP address may be transmitted along with other RRC configuration messages in steps 10-13. Therefore, the existing RRCReconfiguration message format needs to be modified. There are two methods of modification:

[0154] Method 1: Adding a field, such as referred to as bap-Address redundant or bap-Address-second, to the bap-Config IE (information element) of the RRCReconfiguration message to indicate that the field represents a second BAP address; and

[0155] Method 2: Modify the bap-Address field within the bap-Confg IE of the RRCReconfiguration message to a list such as bap-AddressList. Each entry in this list is a BAP address and its associated information, and this entry is, for example, {bap-Address, 'MCG' / 'SCG'}, or {bap-Address, iab-donor-DU-BAP-Address}.

[0156] Example 2

[0157] In Example 2, the IAB-node (e.g., IAB-node 3 in FIG. 2) is in a state where it is already double-connected to two different IAB-donor-CUs. Therefore, in Example 2, IAB-node 3 is also referred to as a double-connected IAB-node.

[0158] Example 2 is used to illustrate a method for establishing a CU-to-CU redundant path for a descendant node of an IAB-node (e.g., IAB-node 4 in FIG. 2).

[0159] FIG. 6 is a schematic diagram of a method for establishing a CU-to-CU redundant path for a descendant node of an IAB-node in Example 2. For the sake of simplicity, possible nodes between a descendant IAB-node and a duplex IAB-node are not shown. Differences between FIG. 6 and FIG. 5 will be described below, and for identical or similar steps therein, the description of Example 1 may be referenced.

[0160] As illustrated in FIG. 6, the setup process includes the following steps:

[0161] 1. IAB-donor-CU 1 initiates a traffic offloading request to IAB-donor-CU 2, and the traffic offloading request includes a request to establish a redundant path to the descendant nodes of the duplex-linked IAB-node;

[0162] 4-7. Steps 4-7 are identical to Steps 4-7 of Example 1, wherein if no duplicate path has previously been established for the IAB-node or other descendant IAB-nodes, a second BAP address is assigned to the dual-linked IAB-node; additionally, if a second BAP address has already been assigned to the dual-linked IAB-node, Steps 4-7 may be skipped and not executed;

[0163] 8. If necessary, for descendant nodes on the second path, IAB-donor-CU 2 performs BH RLC channel configuration and BAP sublayer routing entry configuration between the dual-linked IAB-node and IAB-donor-DU 2, and this method is the same as the method for the dual-linked IAB-node of Example 1.

[0164] 10. Similar to step 10 of FIG. 1, IAB-donor-CU 1 configures one or more TNL addresses for descendant IAB-nodes according to a response message from IAB-donor-CU 2, and one or more TNL addresses are anchored in IAB donor-DU 2;

[0165] 14. IAB-donor-CU 1 performs the configuration of BH RLC channels between the duplex IAB-node and the descendant access IAB-node and the configuration of BAP sublayer routing entries (configuration of BAP routes and mapping rules following the path between the access IAB-node and the duplex IAB-node for the redundant path) to support routing of the second path and BH RLC channel mapping; and IAB-donor-CU 1 performs the configuration of BAP routing ID mapping on the duplex IAB-node based on a response message from IAB-donor-CU 2 (e.g., transmitted in step 9) used for BAP routing transformation between the two topologies. These configurations may be performed earlier, such as immediately after step 10;

[0166] 15. When a new TNL address is assigned in Step 10, the new TNL address is added to the F1-C association of descendant IAB-DU and IAB-donor-CU 1, and IAB-donor-CU 1 constitutes new uplink backhaul information (UL BH information) for F1AP messages of the second path;

[0167] 16. IAB-donor-CU 1 migrates the F1-U tunnel between IAB-donor-CU 1 and IAB-DU, a descendant of the duplexly connected IAB-node, from the first path to the second path via the UE CONTEXT MODIFICATION REQUEST message;

[0168] 17. The descendant IAB-DU sends a response with a UE CONTEXT MODIFICATION RESPONSE message.

[0169] Accordingly, a second path of a descendant node of a dual-connected IAB-node can be established, and uplink user data or downlink user data can be transmitted between the user equipment (UE) and the first IAB-donor-CU through the second path.

[0170] For example, as illustrated in FIG. 6, the transmission order of uplink user data on the second path is: UE--child node--duplex IAB-node--second parent node--intermediate hop IAB-node on the second path--donor-DU on the second path (e.g., donor-DU 2 in FIG. 2)--first IAB-donor-CU.

[0171] As another example, as illustrated in FIG. 6, the transmission order of downstream user data on the second path is as follows: first IAB-donor-CU--donor-DU on the second path (e.g., donor-DU 2 in FIG. 2)--intermediate hop IAB-node on the second path--second parent node--duplex IAB-node--UE.

[0172] Based on different implementations, the process of establishing a redundant path for a descendant IAB-node may be executed after establishing a redundant path for a doubly connected IAB-node, that is, the process of Fig. 6 may be executed after the process of Fig. 5. Alternatively, the process of establishing a redundant path for a descendant IAB-node may be executed simultaneously with establishing a redundant path for a doubly connected IAB-node, that is, the process of Fig. 6 may be executed simultaneously with the process of Fig. 5.

[0173] Example 3

[0174] In Example 3, before the redundant path of the IAB-node is established, the IAB-node (e.g., IAB-node 3 in FIG. 2) is a single-connecting node, that is, the IAB-node is connected to IAB-donor-CU 1.

[0175] When IAB-donor-CU 1 determines that traffic in this topology network is overloaded and network topologies managed by other donor-CUs are needed for traffic offloading, an operation to add an SN (e.g., IAB-donor-CU 2 in FIG. 2) on the IAB-node is performed, that is, the IAB-node is made into a cross-donor (i.e., CU-to-CU) duplex connection, and some traffic is offloaded to the topology of IAB-donor-CU 2 to establish a redundant path.

[0176] FIG. 7 illustrates a schematic diagram of adding an SN to an IAB-node to change it into a dual-linked node and establishing a redundant path. For the sake of simplicity, regarding the step of assigning a second BAP address by the IAB-node in a dual-linked state, one may refer to steps 5-7 of FIG. 5, and thus, these are not illustrated in FIG. 7. The main differences between the process illustrated in FIG. 7 and the process illustrated in FIG. 5 will be explained below, and the same parts will not be repeated.

[0177] The process of Fig. 7 includes the following steps:

[0178] 1. The IAB-MT transmits a measurement report (e.g., MeasurementReport) message to the IAB-DU of the first parent node, and this message is generated according to a measurement configuration (e.g., Measurement Configuration) previously received by the IAB-MT from IAB-donor CU 1;

[0179] 2. The IAB-DU of the first parent node sends a UL RRC MESSAGE TRANSFER message to IAB-donor-CU 1 to transmit the received MeasurementReport;

[0180] 3. IAB-donor CU 1 initiates an S-NODE ADDITION REQUEST message to IAB-donor-CU 2 to add an SN, this message carrying a traffic offloading request, i.e., a request to establish a redundant path for an IAB-node (e.g., IAB-node 3 in FIG. 2), and for specific signaling, refer to Example 4. If IAB-donor-CU 2 rejects the request to add an SN, it may transmit a response rejecting traffic offloading without executing subsequent steps. If IAB-donor-CU 2 agrees to the request to add an SN but rejects the traffic offloading request, it performs the process of directly adding an SN according to existing standards. The response message contains a rejection of traffic offloading, and these subsequent steps do not need to be executed;

[0181] 4. If IAB-donor-CU 2 agrees to or partially agrees to the traffic offloading request, IAB-donor-CU 2 sends a UE CONTENT SETUP REQUEST message to the IAB-DU of the second parent node of the IAB-node to set up the UE context of the IAB-MT and set up one or more bearers, and one or more bearers are used for signaling of its own IAB-MT and optional data traffic.

[0182] 5. The IAB-DU of the second parent node of the IAB-node sends a response to the UE CONTENT SETUP RESPONSE message to the IAB-donor CU 2.

[0183] 7. IAB-donor-CU 2 sends a response to the SN Addition Request Acknowledgment (S-NODE ADDION REQUEST ACKNOWLEDGE) message to IAB-donor-CU 1, and this message includes an IE agreeing to traffic offloading.

[0184] 12. IAB-donor-CU 1 sends a secondary node reconfiguration completion (e.g., S-NODE RECONFIGURATION COMPLETE) message to IAB-donor-CU 2, and this message indicates that the duplex connection configuration of the IAB-node has been successfully completed;

[0185] 13. The IAB-node performs a random access procedure on the IAB-DU of the second parent node.

[0186] The description of the other steps of FIG. 7 is the same as that of Example 1. Additionally, in FIG. 7, if the message in step 3 further includes a request to establish a duplicate path for a descendant IAB-node, the corresponding operations may be performed according to Example 2.

[0187] Example 4

[0188] Example 4 describes the signaling between IAB-donor-CU 1 and IAB-donor-CU 2, namely the XnAP (Xn Application Protocol) procedure. IAB-donor-CU 1 sends a traffic offloading request to IAB-donor-CU 2, and this request is used to migrate F1-C or one or more F1-U tunnels to a topology redundant path of IAB-donor-CU 2.

[0189] For Examples 1 and 2, a new dual-connection related XnAP procedure (e.g., a traffic offloading procedure) and a new XnAP message may be added.

[0190] FIG. 8 is a schematic diagram of the success of the traffic offloading procedure. As shown in FIG. 8, NG-RAN node 1 (i.e., IAB-donor-CU 1) sends a traffic offloading request message, such as the TRAFFIC OFFLOAD REQUEST message, to NG-RAN node 2 (i.e., IAB-donor-CU 2). NG-RAN node 2 sends a response in the form of an acceptance or partial acceptance message, such as the TRAFFIC OFFLOAD REQUEST ACKNOWLEDGE message. Partial acceptance refers to establishing redundant paths for F1-Cs associated with some TNLs, or establishing redundant paths for some F1-U tunnels.

[0191] FIG. 9 is a schematic diagram of a failure of the traffic offloading procedure. As shown in FIG. 9, NG-RAN node 1 (i.e., IAB-donor-CU 1) sends a traffic offloading request message, such as a TRAFFIC OFFLOAD REQUEST message, to NG-RAN node 2 (i.e., IAB-donor-CU 2). If NG-RAN node 2 has a relatively high traffic load or other failures occur, all traffic offloading requests may be rejected, and thus, redundant paths are not established. This traffic offloading rejection message may be referred to as a TRAFFIC OFFLOAD REQUEST REJECT message, which may include the reason for the failure.

[0192] The traffic offloading request message may include the UE XnAP ID of the traffic offloading initiating node and / or identification information of one or more F1-Cs, thereby establishing redundant paths to one or more access IAB-nodes. These access IAB-nodes may be duplex IAB-nodes or IAB-nodes that will soon become duplex IAB-nodes, or descendant IAB-nodes of duplex IAB-nodes. The traffic offloading request message may additionally include the BAP address of the access IAB-node. The F1-C identification information may be a TNL association or TNL association transport layer information (e.g., the IAB-DU control plane transport layer address, i.e., the TNL address). Traffic offloading of the F1-C may be performed explicitly for the TNL association, or the performance of traffic offloading of the F1-C for the TNL association may be implicitly indicated by not providing information for the F1-U.

[0193] When a traffic offloading request for F1-C is accepted, the Traffic Offload Request Acknowledge message may include the UE XnAP ID of the traffic offloading initiating node, the UE XnAP ID of the traffic offloading accepting node, identification information of F1-C, the TNL address newly assigned by IAB-donor-DU 2 for the access IAB-DU, the BH RLC channel ID configured for F1-C on the link between the dual-linked IAB-node and the second parent node, the BAP address of the second parent node, BAP routing identifiers (including uplink and downlink) in the topology controlled by CU 2, and possible second BAP addresses of the dual-linked IAB-node, etc. The BAP address of the second parent node is used by the node's next hop in configuring uplink routing of the redundant path when donor-CU 1 configures a routing entry for the dual-linked IAB-node. The BAP routing identifier in the topology controlled by donor-CU 2 refers to the uplink or downlink BAP routing identifier between donor-DU 2 and the duplex IAB-node, and is used by donor-CU 1 to configure the BAP routing identifier mapping for the duplex IAB-node.

[0194] The traffic offloading request message may further include identification information of data radio bearers (DRBs) indicating the establishment of one or more F1-U tunnels, i.e., redundant paths for these F1-U tunnels. The F1-U tunnel identification information may be user plane (UP) transport layer information including a transport layer address and a GTP-TEID (GPRS tunnelling protocol-tunnel endpoint ID). The request message may further include the BAP address and TNL address of the access IAB-node, IP header information of the F1-U, and QoS information, etc. The IP header information is used by donor-DU 2 to perform traffic mapping from the IP layer to layer 2, and the QoS information is used to perform BH RLC channel selection and configuration at the hops of the redundant path. The QoS information may be the DRB QoS IE defined in TR38.473, or part of the information within the IE, such as the 5G QoS identifier (5QI). When a traffic offloading request for an F1-U tunnel is accepted or partially accepted, the traffic offload request acknowledgment message may include identification information of the received F1-U tunnel and a BH RLC channel identifier on the link between the dual-linked IAB node configured for the F1-U tunnel and the second parent node, and may additionally include a new TNL address, a BAP address of the second parent node, a BAP routing identifier within the topology controlled by CU 2 (including uplink and downlink), and a possible second BAP address of the dual-linked IAB node, etc.

[0195] When dual connectivity exists and an MN initiates a traffic offloading request, the contents of these request and response messages are also taken as IEs and can be included in the existing XnAP S-NG-RAN node modification readiness procedure; that is, existing messages such as S-NODE MODIFICATION REQUEST, S-NODE MODIFICATION REQUEST ACKNOWLEDGE, and S-NODE MODIFICATION REJECT are reused. When existing messages are reused, if all traffic offloading requests are rejected but any other modification requests are agreed upon, the S-NODE MODIFICATION REQUEST ACKNOWLEDGE message is still used. The S-NODE MODIFICATION REJECT message is used only when any modification request is not agreed upon and any traffic offloading request is not agreed upon, or when a failure occurs.

[0196] In the case of Example 3, the contents of these messages are taken as IEs and can be included in the existing XnAP S-NG-RAN node addition preparation process. That is, existing messages such as S-NODE ADDION REQUEST, S-NODE ADDION REQUEST ACKNOWLEDGE, and S-NODE ADDION PROJECT are reused. When existing messages are reused, if all traffic offloading requests are rejected but the SN addition request is agreed upon, the S-NODE MODIFICATION REQUEST ACKNOWLEDGE message is still used. The S-NODE MODIFICATION REJECT message is used only when the SN addition request is not agreed upon or when a failure occurs.

[0197] Example 5

[0198] Example 5 is used to describe a process for releasing duplicate paths between IAB-donor-CU 1 and IAB-donor-CU 2.

[0199] Both NG-RAN node 1 (i.e., IAB-donor-CU 1) and NG-RAN node 2 (i.e., IAB-donor-CU 2) can initiate a process to release the redundant path. A new duplex-related XnAP process may be added to perform the release process.

[0200] Both the initiator of traffic offloading (e.g., IAB-donor-CU 1) and the receiver (e.g., IAB-donor-CU 2) can propose the release of redundant paths. FIG. 10 is a schematic diagram of the proposal for redundant path release by the initiator of traffic offloading, and FIG. 11 is a schematic diagram of the proposal for redundant path release by the receiver of traffic offloading.

[0201] As illustrated in FIGS. 10 and 11, different message names may be used to distinguish whether redundant path release is proposed by the initiator of traffic offloading (e.g., IAB-donor-CU 1) or by the receiver (e.g., IAB-donor-CU 2). For example, as illustrated in FIG. 10, the initiator of traffic offloading, i.e., the F1 end donor-node, may send a traffic offload release request message to a non-F1 end donor-node, and the non-F1 end donor-node sends a response of a traffic offload release acknowledgment message; and as illustrated in FIG. 11, the non-F1 end donor-node may send a traffic offload release required message to the F1 end donor-node, and the F1 end donor-node sends a response of a traffic offload release confirm message.

[0202] Traffic offload release request / request messages include the TNL address associated with F1-C requiring redundancy release, or UP transport layer information of the F1-U tunnel requiring redundancy release.

[0203] The specific process for releasing duplicate paths is: releasing BAP routing entries related to the duplicate paths by donor-CU 1 and / or donor-CU 2, if necessary, modifying or releasing the BH RLC channels required by the duplicate paths; and, if necessary, deleting mapping information of the related BAP routing identifiers on the duplex IAB-nodes by donor-CU 1.

[0204] When MN initiates a process to release duplicate paths, the above request and response messages are also taken as IEs and can be included in the existing XnAP S-NG-RAN node modification preparation procedure, that is, existing messages such as S-NODE MODIFICATION REQUEST, S-NODE MODIFICATION REQUEST ACKNOWLEDGE, etc. are reused.

[0205] In the process of S-NG-RAN node release, all redundant paths within the SN topology are released.

[0206] Example of the third aspect

[0207] At least in response to the same problem as that of the embodiment of the first embodiment, the embodiment of the third embodiment of the present disclosure provides a method for transmitting and receiving a signal corresponding to the method of the embodiment of the first embodiment. The method for transmitting and receiving a signal of the embodiment of the third embodiment is applicable to an IAB-node, wherein the IAB-node may be, for example, IAB-node 3 of FIG. 2.

[0208] FIG. 12 is a schematic diagram of a method for transmitting and receiving a signal of an embodiment of a third aspect. As illustrated in FIG. 12, the method comprises the following:

[0209] Operation 1201: A first RRC reconstruction message transmitted by the first IAB-donor-CU is received;

[0210] Operation 1202: An RRC reconfiguration complete message is sent to the 1st IAB-donor-CU, and

[0211] A first RRC reconfiguration message is generated in response to consent to traffic offloading transmitted by the second IAB-donor-CU to the first IAB-donor-CU, and the first RRC reconfiguration message includes at least one TNL address assigned to the DU of the IAB-node, and the TNL address is anchored to the second IAB-donor-DU in the topology of the second IAB-donor-CU.

[0212] The bap configuration information element (bap-Config IE) of the first RRC reconfiguration message includes a field for indicating a second BAP address configured for the IAB-node; or, the bap address field within the bap configuration information element (bap-Config IE) of the first RRC reconfiguration message includes a list, and each entry in the list is a BAP address and its associated information.

[0213] The RRC Reconfiguration Complete (e.g., RRCReconfigurationComplete) message in operation 1202 is used to indicate that the IAB-node has received the first RRC Reconfiguration message. Additionally, the RRC Reconfiguration Complete message may further indicate that the IAB-node has completed the reconfiguration.

[0214] According to Operation 1201 and Operation 1202, a cross-donor duplicate path can be established for an IAB-node.

[0215] As illustrated in FIG. 12, this method further comprises the following:

[0216] Operation 1203: The IAB-node receives a second RRC reconstruction message transmitted by the second IAB-donor-CU;

[0217] Operation 1204: The IAB-node sends a reconfiguration complete message to the second IAB-donor-CU.

[0218] In operation 1203, the second RRC reconfiguration message contains BAP configuration information (bap-Config), and the BAP configuration information contains the second BAP address configured for the IAB-node. And in operation 1204, the reconfiguration complete (RRCReconfigurationComplete) message is used to indicate that the IAB-node has received the second RRC reconfiguration message.

[0219] As illustrated in FIG. 12, this method further comprises the following:

[0220] Operation 1205: The IAB-node associates the second BAP address with the master cell group (MCG) / secondary cell group (SCG) or the master node (MN) / secondary node (SN).

[0221] For example, if a second RRCReconfiguration message carrying a second BAP address received by an IAB-node is from an MCG or received via a signaling radio bearer (SRB) 1, the second BAP address is associated with the MCG or MN; if a second RRCReconfiguration message carrying a second BAP address received by an IAB-node is from an SCG or received via SRB3, the second BAP address is associated with the SCG or SN.

[0222] Example of the fourth aspect

[0223] At least in response to the same problem as that of the embodiment of the first embodiment, the embodiment of the fourth embodiment of the present disclosure provides a method for transmitting and receiving a signal corresponding to the method of the embodiment of the first embodiment. The method for transmitting and receiving a signal of the embodiment of the fourth embodiment is applicable to a descendant node of an IAB-node, wherein the descendant node may be, for example, the IAB-node 4 of FIG. 2.

[0224] FIG. 13 is a schematic diagram of a method for transmitting and receiving a signal of an embodiment of a third aspect. As illustrated in FIG. 13, the method comprises the following:

[0225] Operation 1301: A first RRC reconstruction message transmitted by the first IAB-donor-CU is received;

[0226] Operation 1302: An RRC reconfiguration complete message is sent to the 1st IAB-donor-CU, and

[0227] A first RRC reconfiguration message is generated in response to consent to traffic offloading transmitted by the second IAB-donor-CU to the first IAB-donor-CU, and the first RRC reconfiguration message includes at least one TNL address assigned to a DU of a descendant node, and the TNL address is anchored to the second IAB-donor-DU in the topology of the second IAB-donor-CU;

[0228] The RRC ReconfigurationComplete message in operation 1302 is used to indicate that a child node has received the first RRC reconfiguration message. Additionally, the RRC ReconfigurationComplete message may further indicate that the child node has completed the reconfiguration.

[0229] According to an embodiment of the fourth aspect, a cross-donor duplicate path can be established for the descendant nodes of an IAB-node.

[0230] Example of the fifth aspect

[0231] An embodiment of the present disclosure provides an apparatus for transmitting and receiving a signal applicable to a first IAB-donor-CU. The apparatus may be the first IAB-donor-CU or may be part of the units of the first IAB-donor-CU. The apparatus corresponds to the method of an embodiment of the first aspect.

[0232] FIG. 14 is a schematic diagram of an apparatus for transmitting and receiving a signal according to an embodiment of the present disclosure. As illustrated in FIG. 14, the apparatus (1400) for transmitting and receiving a signal includes a first transmitting and receiving unit (1401), and the first transmitting and receiving unit (1401) comprises:

[0233] Send a traffic offloading request to the 2nd IAB-donor-CU;

[0234] It is configured to receive a response of consent to traffic offloading or a response of refusal to traffic offloading transmitted by the second IAB-donor-CU.

[0235] In at least one embodiment, the first transmitting and receiving unit (1401) is further configured to transmit a first RRC reconfiguration message to an IAB-node and / or a descendant IAB-node of the IAB-node in response to consent to traffic offloading, and

[0236] The first RRC reconfiguration message includes at least one TNL address assigned to the DU of the IAB-node and / or the DU of the descendant node of the IAB-node, respectively, the TNL address is anchored to the second IAB-donor-DU in the topology of the second IAB-donor-CU, the IAB-node is connected to the first parent node, the first parent node is a node in the topology of the first IAB-donor-CU, the IAB-node is already connected to or will be connected to the second parent node, and the second parent node is a node in the topology of the second IAB-donor-CU.

[0237] In at least one embodiment, the BAP configuration information element (bap-Config IE) of the first RRC reconfiguration message includes a field used to indicate a second BAP address configured for an IAB-node; or the BAP address field within the BAP configuration information element (bap-Config IE) of the first RRC reconfiguration message includes a list, and each entry in the list is a BAP address and its associated information.

[0238] In at least one embodiment, the first transmitting and receiving unit is:

[0239] When a new TNL address is assigned, it is further configured to add the new TNL address to the F1-C association between the DU of the IAB-node and / or the DU of its descendant node and the first IAB-donor-CU.

[0240] In at least one embodiment, the traffic offloading request includes a request to set redundant paths for the IAB-node and / or the descendant nodes of the IAB-node.

[0241] In at least one embodiment, the first transmitting and receiving unit (1401) is:

[0242] The first IAB-donor-CU is further configured to support routing of the second path and BH RLC channel mapping by performing the configuration of the BH RLC channel between the IAB-node and the descendant nodes of the IAB-node and the configuration of the BAP sublayer routing entry.

[0243] In at least one embodiment, the first transmitting and receiving unit (1401) is:

[0244] The first IAB-donor-CU is further configured to perform the configuration of BAP routing ID mapping for the IAB-node in response to the consent for traffic offloading.

[0245] In at least one embodiment, the first transmitting and receiving unit (1401) is:

[0246] The first IAB-donor-CU is further configured to migrate the F1-U tunnel between the first IAB-donor-CU and the DU of the IAB-node and / or the descendant node of the IAB-node from the first path to the second path via the UE CONTEXT MODIFICATION REQUEST message or the UE CONTEXT SETUP REQUEST message.

[0247] In at least one embodiment, the response to the consent of traffic offloading indicates that the traffic offloading request is at least partially accepted, and that the traffic offloading request is at least partially accepted refers to that redundant paths are established for some TNL-associated F1-Cs or for some F1-U tunnels.

[0248] In at least one embodiment, the IAB-node is connected to a first parent node, the IAB-node is connected to a second parent node, the first parent node is a node in the topology of the first IAB-donor-CU, and the second parent node is a node in the topology of the second IAB-donor-CU. A traffic offloading request is included in a traffic offloading request message, a response agreeing to traffic offloading is included in a traffic offloading request acknowledge message, and a response rejecting traffic offloading is included in a traffic offloading request reject message.

[0249] In at least one embodiment, the traffic offloading request message includes an identifier (UE XnAP ID) of the user equipment of the traffic offloading initiation node in the Xn interface, and / or one or more F1-C identification information, the F1-C identification information is used to establish redundant paths for one or more F1-Cs of the access IAB-node, and the access IAB-node includes an IAB-node and / or a descendant node of the IAB-node or an IAB-node that will soon become a dual-connected node.

[0250] In at least one embodiment, the traffic offloading request message is:

[0251] It includes at least one of the UE XnAP ID of the traffic offloading initiation node, the BAP address of the access IAB-node, the TNL address, one or more F1-C identification information, the IP header information of the F1-C and / or F1-U tunnels, or the QoS information of the F1-U tunnels.

[0252] In at least one embodiment, when a traffic offloading request for the F1-C and / or F1-U tunnel is accepted, the traffic offloading request acknowledgment message is:

[0253] It includes at least one of the UE XnAP ID of the traffic offloading initiation node, the UE XnAP ID of the traffic offloading acceptance node, identification information of the F1-C and / or F1-U tunnel, a newly assigned TNL address for the DU of the access IAB-node, a BH RLC channel identifier on the link between the dual-link IAB-node and the second parent node configured for the F1-C and / or F1-U tunnel, the BAP address of the second parent node, a BAP routing identifier in the topology controlled by the second IAB-donor-CU, or the second BAP address of the IAB-node.

[0254] In at least one embodiment, when traffic offloading requests for all F1-C and F1-U tunnels are denied, the traffic offloading request denial message includes the UE XnAP ID of the traffic offloading initiation node.

[0255] In at least one embodiment, the IAB-node is connected to a first parent node, the IAB-node is connected to a second parent node, the first parent node is a node in the topology of the first IAB-donor-CU, and the second parent node is a node in the topology of the second IAB-donor-CU.

[0256] The first IAB-donor-CU is a master node (MN), and the contents of the traffic offloading request and the contents of the response agreeing to or rejecting the traffic offloading are taken as information elements (IEs) and included in the messages of the XnAP S-NG-RAN node modification preparation procedure.

[0257] In at least one embodiment, the IAB-node is connected to a first parent node, and the IAB-node is not connected to a second parent node, the first parent node is a node in the topology of the first IAB-donor-CU, and the second parent node is a node in the topology of the second IAB-donor-CU, and

[0258] The contents of the traffic offloading request and the contents of the response agreeing to or rejecting traffic offloading are taken as information elements (IEs) and included in the messages of the XnAP S-NG-RAN node addition preparation process.

[0259] In at least one embodiment, the traffic offloading request is included in an auxiliary node addition request (S-NODE ADDITION REQUEST) message transmitted by the first IAB-donor-CU to the second IAB-donor-CU.

[0260] In at least one embodiment, the response to the consent for traffic offloading is included in an auxiliary node addition request acknowledgment (S-NODE ADDITION REQUEST ACKNOWLEDGE) message sent by the second IAB-donor-CU to the first IAB-donor-CU.

[0261] In at least one embodiment, the response to the refusal of traffic offloading is included in an S-NODE ADDITION REQUEST ACKNOWLEDGE message transmitted by the second IAB-donor-CU to the first IAB-donor-CU.

[0262] In at least one embodiment, the first transmitting and receiving unit (1401) is:

[0263] Sending or receiving a duplicate path release request by the 1st IAB-donor-CU;

[0264] It is further configured to receive or send a message accepting a duplicate path release request by the 1st IAB-donor-CU.

[0265] In at least one embodiment, the redundant path release request includes the UE XnAP ID of the traffic offloading initiation node, the UE XnAP ID of the traffic offloading acceptance node, and the TNL address associated with F1-C that needs to be released from the redundant path, or User Plane Transport Layer Information (UP Transport Layer Information) of the F1-U tunnel that needs to be released from the redundant path.

[0266] In at least one embodiment, the duplicate path release request includes the UE XnAP ID of the traffic offloading initiation node and the UE XnAP ID of the traffic offloading acceptance node.

[0267] In at least one embodiment, when MNs in the first IAB-donor-CU and the second IAB-donor-CU transmit duplicate path release requests,

[0268] The contents of duplicate path release requests and duplicate path release request acceptance messages are taken as IEs and included in the S-NG-RAN node modification preparation process.

[0269] In at least one embodiment, when performing the auxiliary base station node release (S-NG-RAN node Release) process of the IAB-node, all redundant paths related to the IAB-node in the SN topology are released.

[0270] For a detailed description of the first transmitting and receiving unit (1401), refer to the description of the method in the embodiment of the first aspect.

[0271] Example of the 6th aspect

[0272] An embodiment of the present disclosure provides an apparatus for transmitting and receiving a signal applicable to a second IAB-donor-CU. The apparatus may be the second IAB-donor-CU or one or more components or assemblies configured in the second IAB-donor-CU. The apparatus corresponds to the method of an embodiment of a second aspect.

[0273] FIG. 15 is a schematic diagram of a device for transmitting and receiving a signal of an embodiment of the sixth aspect. As illustrated in FIG. 15, the device (1500) for transmitting and receiving a signal includes a second transmitting and receiving unit (1501), and the second transmitting and receiving unit (1501) comprises:

[0274] Receive a traffic offloading request sent by the 1st IAB-donor-CU;

[0275] It is configured to send a response of consent to traffic offloading or a response of refusal to traffic offloading to the first IAB-donor-CU.

[0276] In at least one embodiment, the traffic offloading request includes a request to establish redundant paths for the IAB-node and / or the descendant nodes of the IAB-node.

[0277] In at least one embodiment, the second transmitting and receiving unit (1501) is:

[0278] When the IAB-node is already connected to the second parent node, the second IAB-donor-CU sends a UE context modification request message to the second parent node to modify the User Equipment (UE) context of the IAB-node's Mobile Terminal (MT), and is further configured to establish at least one bearer, and the second parent node is a node in the topology of the second IAB-donor-CU.

[0279] In at least one embodiment, the second transmitting and receiving unit (1501) is:

[0280] When the IAB-node is not connected to the second parent node, the second IAB-donor-CU sends a UE context setup request message to the second parent node to set up the UE context of the IAB's MT, and is further configured to set up at least one bearer,

[0281] The second parent node is a node in the topology of the second IAB-donor-CU.

[0282] In at least one embodiment, the second transmitting and receiving unit (1501) is:

[0283] The second IAB-donor-CU is further configured to transmit a second RRC-Reconfiguration message to the mobile terminal (MT) of the IAB-node, and the second RRC-Reconfiguration message includes BAP configuration information (bap-Config), and the BAP configuration information includes the address of the second BAP configured for the IAB-node.

[0284] In at least one embodiment, the second transmitting and receiving unit (1501) is:

[0285] For a second path required by an IAB-node and / or a descendant node of an IAB-node, the second IAB-donor-CU is additionally configured to perform the configuration of a BH RLC channel between the IAB-node and the second IAB-donor-DU and the configuration of routing entries in the BAP sublayer, and

[0286] The second IAB-donor-DU is within the topology of the second IAB-donor-CU.

[0287] In at least one embodiment, the response to the consent of traffic offloading indicates that the traffic offloading request is at least partially accepted, and that the traffic offloading request is at least partially accepted refers to that redundant paths are established for some TNL-associated F1-Cs or for some F1-U tunnels.

[0288] In at least one embodiment, the IAB-node is connected to a first parent node, the IAB-node is connected to a second parent node, the first parent node is a node in the topology of the first IAB-donor-CU, and the second parent node is a node in the topology of the second IAB-donor-CU.

[0289] A traffic offloading request is included in the traffic offloading request message, a response agreeing to traffic offloading is included in the traffic offloading request acknowledgment message, and a response rejecting traffic offloading is included in the traffic offloading request rejection message.

[0290] In at least one embodiment, the traffic offloading request message includes an identifier (UE XnAP ID) of the user equipment of the traffic offloading initiation node in the Xn interface, and / or one or more F1-C identification information, the F1-C identification information is used to establish redundant paths for one or more F1-Cs of the access IAB-node, and the access IAB-node includes an IAB-node and / or a descendant node of the IAB-node or an IAB-node that will soon become a dual-connected node.

[0291] In at least one embodiment, the traffic offloading request message is:

[0292] It includes at least one of the UE XnAP ID of the traffic offloading initiation node, the BAP address of the access IAB-node, the TNL address, one or more F1-C identification information, the IP header information of the F1-C and / or F1-U tunnels, or the QoS information of the F1-U tunnels.

[0293] In at least one embodiment, when a traffic offloading request for the F1-C and / or F1-U tunnel is accepted, the traffic offloading request acknowledgment message is:

[0294] It includes at least one of the UE XnAP ID of the traffic offloading initiation node, the UE XnAP ID of the traffic offloading acceptance node, identification information of the F1-C and / or F1-U tunnel, a newly assigned TNL address for the DU of the access IAB-node, a BH RLC channel identifier on the link between the dual-link IAB-node and the second parent node configured for the F1-C and / or F1-U tunnel, the BAP address of the second parent node, a BAP routing identifier in the topology controlled by the second IAB-donor-CU, or the second BAP address of the IAB-node.

[0295] In at least one embodiment, when traffic offloading requests for all F1-C and F1-U tunnels are denied, the traffic offloading request denial message includes the UE XnAP ID of the traffic offloading initiation node and may optionally include the UE XnAP ID of the traffic offloading denial node.

[0296] In at least one embodiment, the IAB-node is connected to a first parent node, the IAB-node is connected to a second parent node, the first parent node is a node in the topology of the first IAB-donor-CU, and the second parent node is a node in the topology of the second IAB-donor-CU.

[0297] The first IAB-donor-CU is the master node (MN), and the contents of the traffic offloading request and the contents of the response agreeing to or rejecting the traffic offloading are taken as information elements (IEs) and included in the messages of the XnAP S-NG-RAN node modification preparation process.

[0298] In at least one embodiment, the IAB-node is connected to a first parent node, and the IAB-node is not connected to a second parent node, the first parent node is a node in the topology of the first IAB-donor-CU, and the second parent node is a node in the topology of the second IAB-donor-CU, and

[0299] The contents of the traffic offloading request and the contents of the response agreeing to or rejecting traffic offloading are taken as information elements (IEs) and included in the messages of the XnAP S-NG-RAN node addition preparation process.

[0300] In at least one embodiment, the traffic offloading request is included in an auxiliary node addition request (S-NODE ADDITION REQUEST) message transmitted by the first IAB-donor-CU to the second IAB-donor-CU.

[0301] In at least one embodiment, the response to the consent for traffic offloading is included in an auxiliary node addition request acknowledgment (S-NODE ADDITION REQUEST ACKNOWLEDGE) message sent by the second IAB-donor-CU to the first IAB-donor-CU.

[0302] In at least one embodiment, the second transmitting and receiving unit (1501) is:

[0303] Receive or send a request to release duplicate paths by the 2nd IAB-donor-CU;

[0304] It is additionally configured to send or receive a message accepting a duplicate path release request by the second IAB-donor-CU.

[0305] In at least one embodiment, the redundant path release request includes the UE XnAP ID of the traffic offloading initiation node, the UE XnAP ID of the traffic offloading acceptance node, and the TNL address associated with F1-C that needs to be released from the redundant path, or User Plane Transport Layer Information (UP Transport Layer Information) of the F1-U tunnel that needs to be released from the redundant path.

[0306] In at least one embodiment, when MNs in the first IAB-donor-CU and the second IAB-donor-CU transmit duplicate path release requests,

[0307] The contents of duplicate path release requests and duplicate path release request acceptance messages are taken as IEs and included in the S-NG-RAN node modification preparation process.

[0308] In at least one embodiment, when performing the auxiliary base station node release (S-NG-RAN node Release) process of the IAB-node, all redundant paths related to the IAB-node in the SN topology are released.

[0309] For a detailed description of the second transmitting and receiving unit (1501), refer to the description of the method in the embodiment of the second aspect.

[0310] Example of the 7th aspect

[0311] An embodiment of the present disclosure provides an apparatus for transmitting and receiving signals applicable to an IAB-node. The apparatus may be an IAB-node or one or more components or assemblies configured in an IAB-node. The apparatus corresponds to the method of an embodiment of a third aspect.

[0312] FIG. 16 is a schematic diagram of a device for transmitting and receiving a signal of an embodiment of the seventh aspect. As illustrated in FIG. 16, the device (1600) for transmitting and receiving a signal includes a third transmitting and receiving unit (1601), and the third transmitting and receiving unit (1601) comprises:

[0313] Receive the first RRC reconstruction message transmitted by the first IAB-donor-CU;

[0314] It is configured to send an RRC reconstruction completion message to the first IAB-donor-CU.

[0315] In at least one embodiment, a first RRC reconfiguration message is generated in response to consent to traffic offloading transmitted by the second IAB-donor-CU to the first IAB-donor-CU, and the first RRC reconfiguration message includes at least one TNL address assigned to the DU of the IAB-node, the TNL address is anchored to the second IAB-donor-DU in the topology of the second IAB-donor-CU, and an RRC Reconfiguration Complete message is used to indicate that the IAB-node has received the first RRC reconfiguration message. Additionally, the RRC Reconfiguration Complete message may indicate that the IAB-node has completed the reconfiguration.

[0316] In at least one embodiment, the third transmitting and receiving unit (1601) is:

[0317] By the IAB-node, receive a second RRC reconfiguration message transmitted by the second IAB-donor-CU - the second RRC reconfiguration message includes BAP configuration information (bap-Config), and the BAP configuration information includes a second BAP address configured for the IAB-node - ;

[0318] It is additionally configured to send a reconstruction completion message by the IAB-node to the second IAB-donor-CU, and

[0319] The reconfiguration complete message is used to indicate that the IAB-node has received the second RRC reconfiguration message.

[0320] In at least one embodiment, the third transmitting and receiving unit (1601) is:

[0321] The IAB-node is further configured to associate a second BAP address with a master cell group (MCG) / secondary cell group (SCG) or a master node (MN) / secondary node (SN).

[0322] In at least one embodiment, if a second RRCReconfiguration message carrying a second BAP address received by an IAB-node is from an MCG or received via a signaling radio bearer (SRB) 1, the second BAP address is associated with the MCG or MN;

[0323] If a second RRCReconfiguration message carrying a second BAP address received by an IAB-node is from SCG or received via SRB3, the second BAP address is associated with SCG or SN.

[0324] In at least one embodiment, the bap configuration information element (bap-Config IE) of the first RRC reconfiguration message includes a field used to indicate a second BAP address configured for the IAB-node; or

[0325] The bap address field within the BAP configuration information element (bap-Config IE) of the first RRC reconfiguration message contains a list, and each entry in the list is a BAP address and its associated information.

[0326] For a detailed description of the third transmitting and receiving unit (1601), refer to the description of the method in the embodiment of the third aspect.

[0327] Example of the 8th aspect

[0328] An embodiment of the present disclosure provides an apparatus for transmitting and receiving signals applicable to a descendant node of an IAB-node. The apparatus may be a descendant node, or one or more components or assemblies configured in a descendant node. The apparatus corresponds to the method of an embodiment of a fourth aspect.

[0329] FIG. 17 is a schematic diagram of a device for transmitting and receiving a signal of an embodiment of the eighth aspect. As illustrated in FIG. 17, the device (1700) for transmitting and receiving a signal includes a fourth transmitting and receiving unit (1701), and the fourth transmitting and receiving unit (1701) comprises:

[0330] Receive the first RRC reconstruction message transmitted by the first IAB-donor-CU;

[0331] It is configured to send an RRC reconfiguration completion message to the first IAB-donor-CU, and

[0332] A first RRC reconfiguration message is generated in response to consent to traffic offloading transmitted by the second IAB-donor-CU to the first IAB-donor-CU, and the first RRC reconfiguration message includes at least one TNL address assigned to a DU of a descendant node, and the TNL address is anchored to the second IAB-donor-DU in the topology of the second IAB-donor-CU;

[0333] The RRC reconfiguration complete message is used to indicate that a child node has received the first RRC reconfiguration message. Additionally, the RRC reconfiguration complete message can indicate that the child node has completed the reconfiguration.

[0334] For a detailed description of the fourth transmitting and receiving unit (1701), refer to the description of the method in the embodiment of the fourth aspect.

[0335] Example of the ninth aspect

[0336] Embodiments of the present disclosure provide a communication system, and reference may be made to FIG. 1, and contents identical to those in embodiments of the first through eighth embodiments will not be described further herein.

[0337] In some embodiments, the communication system is:

[0338] A first IAB-donor-CU comprising a device (1400) for transmitting and receiving signals as described in the embodiment of the fifth aspect;

[0339] A second IAB-donor-CU comprising a device (1500) for transmitting and receiving signals as described in the embodiment of the sixth aspect;

[0340] An IAB-node comprising a device (1600) for transmitting and receiving signals as described in the embodiment of the seventh aspect; and

[0341] It may include a descendant node of an IAB-node, which includes a device (1700) for transmitting and receiving signals as described in the embodiment of the eighth aspect.

[0342] The IAB-node may include an IAB-MT functional unit and an IAB-DU functional unit, the IAB-MT functional unit has the same structure as the terminal equipment, and the IAB-DU functional unit, the first IAB-donor-CU, and the second IAB-donor-CU have units identical to the network device.

[0343] FIG. 18 is a schematic diagram of the structure of a network device of an embodiment of the present disclosure. As shown in FIG. 18, the network device (1800) may include a processor (1810) (e.g., a central processing unit (CPU)) and a memory (1820), and the memory (1820) is coupled to the processor (1810). The memory (1820) may store various data and may also store a program (1830) for information processing and execute the program (1830) under the control of the processor (1810).

[0344] For example, the processor (1810) may be configured to execute a program for executing a method executed by IAB-DU in an embodiment of the first or second embodiment or a method executed by IAB-DU in an embodiment of the third or fourth embodiment.

[0345] Additionally, as illustrated in FIG. 18, the network device (1800) may include a transceiver (1840) and an antenna (1850), etc. The functions of the above components are similar to the functions of the components of the relevant technology and will not be described further here. It should be noted that the network device (1800) does not necessarily include all parts illustrated in FIG. 18, and the network device (1800) may include parts not illustrated in FIG. 18, and the relevant technology may be referenced. Additionally, the IAB-donor-CU and IAB-donor-DU may exist in a node and act as a network device IAB-donor, or may be separated into two nodes that each perform functions different from the functions of the network device, and existing techniques may be referenced.

[0346] FIG. 19 is a schematic diagram of terminal equipment in an embodiment of the present disclosure. As illustrated in FIG. 19, terminal equipment (1900) may include a processor (1910) and a memory (1920), and the memory (1920) stores data and programs and is coupled to the processor (1910). It should be noted that these drawings are merely exemplary and that other types of structures may be used to supplement or replace this structure and to achieve telecommunications functions or other functions. For example, the processor (1910) may be configured to execute a program for performing a method executed by IAB-MT in an embodiment of a third or fourth aspect.

[0347] As illustrated in FIG. 19, the terminal equipment (1900) may additionally include a communication module (1930), an input unit (1940), a display (1950), and a power supply (1960); the functions of the above components are similar to the functions of the components of the relevant art, which will not be described further herein. It should be noted that the terminal equipment (1900) does not necessarily include all parts illustrated in FIG. 19, and the above components are not required. Additionally, the terminal equipment (1900) may include parts not illustrated in FIG. 19, and the relevant art may be referenced.

[0348] An embodiment of the present disclosure provides a computer-readable program that, when executed in a donor-CU, causes the donor-CU to perform a method as described in an embodiment of a first or second aspect.

[0349] An embodiment of the present disclosure provides a computer storage medium comprising a computer-readable program that enables a donor-CU to perform a method as described in an embodiment of a first or second aspect.

[0350] An embodiment of the present disclosure provides a computer-readable program that, when executed at an IAB or its descendant node, causes the IAB node or its descendant node to perform a method for transmitting and receiving a signal as described in an embodiment of a third or fourth aspect.

[0351] An embodiment of the present invention provides a computer storage medium comprising a computer-readable program that enables an IAB node or its descendant node to perform a method for transmitting and receiving a signal as described in an embodiment of a third or fourth aspect.

[0352] The above devices and methods of the present disclosure may be implemented by hardware or by hardware combined with software. The present disclosure relates to such computer-readable programs, and when a program is executed by a logic device, the logic device is enabled to execute the devices or components as described above, or to execute the methods or steps as described above. The present disclosure also relates to storage media for storing the above programs, such as hard disks, floppy disks, CDs, DVDs, and flash memory.

[0353] The methods / devices described with reference to the embodiments of the present disclosure may be directly implemented as hardware, software modules executed by a processor, or a combination thereof. For example, one or more functional block diagrams and / or one or more combinations of functional block diagrams shown in the drawings may correspond to software modules of procedures of a computer program or to hardware modules. These software modules may each correspond to the steps shown in the drawings. And, the hardware modules may be implemented by firming the software modules using, for example, a field programmable gate array (FPGA).

[0354] Soft modules may be located on RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disks, floppy disks, CD-ROMs, or any other form of memory medium known in the art. Since the memory medium may be coupled to the processor, the processor may read information from the memory medium and write information to the memory medium; or the memory medium may be a component of the processor. The processor and the memory medium may be located within an ASIC. Soft modules may be stored in the memory of a mobile terminal and may also be stored on a memory card of a pluggable mobile terminal. For example, if the equipment (such as a mobile terminal) uses a relatively large capacity MEGA-SIM card or a large capacity flash memory device, the soft modules may be stored on the large capacity MEGA-SIM card or flash memory device.

[0355] One or more functional blocks and / or one or more combinations of functional blocks in the drawings may be realized as general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or any suitable combination thereof performing the functions described in this application. And one or more functional block diagrams and / or one or more combinations of functional block diagrams in the drawings may also be realized as a combination of a DSP and a microprocessor, a plurality of processors, one or more microprocessors coupled to communication with a DSP, or any other combination of computing equipment such as such configurations.

[0356] The present disclosure is described above with reference to specific embodiments. However, those skilled in the art should understand that such description is merely illustrative and is not intended to limit the scope of protection of the present disclosure. Various modifications and variations may be made by those skilled in the art in accordance with the spirit and principles of the present disclosure, and such modifications and variations fall within the scope of the present disclosure.

[0357] With respect to embodiments including the above embodiments, the following supplements are further disclosed.

[0358] Method on the 1st IAB-donor-CU side:

[0359] 1. A method for transmitting and receiving signals applicable to a first integrated access and backhaul node donor central unit (IAB-donor-CU), comprising:

[0360] A step of sending a traffic offloading request to the second IAB-donor-CU; and

[0361] A method comprising the step of receiving a response of consent to traffic offloading or a response of refusal to traffic offloading transmitted by the second IAB-donor-CU.

[0362] 2. In Supplement 1, the above method is:

[0363] The method further includes the step of transmitting a first RRC reconfiguration message to an IAB-node and / or a descendant IAB-node of said IAB-node in response to consent to the traffic offloading above, and

[0364] The first RRC reconstruction message includes at least one TNL address assigned to the DU of the IAB-node and / or the DU of the descendant node of the IAB-node, respectively, and the TNL address is anchored to the second IAB-donor-DU in the topology of the second IAB-donor-CU, and

[0365] A method wherein the above IAB-node is connected to a first parent node, the first parent node is a node in the topology of the first IAB-donor-CU, the above IAB-node is already connected to or will be connected to a second parent node, and the second parent node is a node in the topology of the second IAB-donor-CU.

[0366] 3. In Supplement 2,

[0367] The BAP configuration information element (bap-Config IE) of the first RRC reconfiguration message includes a field used to indicate a second BAP address configured for the IAB-node; or

[0368] A method in which the BAP address field within the BAP configuration information element (bap-Config IE) of the first RRC reconfiguration message includes a list, and each entry in the list is a BAP address and its associated information.

[0369] 4. In Supplement 2, the above method is:

[0370] A method further comprising the step of adding the new TNL address to the F1-C association of the DU of the first IAB-donor-CU and the IAB-node and / or the descendant node of the IAB-node when the new TNL address is assigned.

[0371] 5. In Supplement 1,

[0372] A method in which the above traffic offloading request includes a request to establish a redundant path for the above IAB-node and / or descendant nodes of the above IAB-node.

[0373] 6. In Supplement 5, the above method is:

[0374] A method further comprising the step of supporting routing of a second path and BH RLC channel mapping by performing BH RLC channel configuration and BAP sublayer routing entry configuration between the IAB-node and the descendant node of the IAB-node by the first IAB-donor-CU.

[0375] 7. In Supplement 5, the above method is:

[0376] A method further comprising the step of performing BAP routing identifier mapping for the IAB-node by the first IAB-donor-CU in response to consent to the traffic offloading.

[0377] 8. In Supplement 5, the above method is:

[0378] A method further comprising the step of migrating an F1-U tunnel between the first IAB-donor-CU and the DU of the IAB-node and / or the descendant node of the IAB-node from the first path to the second path via a UE context modification request message or a UE context setup request message by the first IAB-donor-CU.

[0379] 9. In Supplement 1,

[0380] The response to the consent for the above traffic offloading indicates that the traffic offloading request is accepted at least partially, and

[0381] A method in which the above traffic offloading request is accepted at least partially, which refers to redundant paths being established for some TNL-associated F1-Cs or some F1-U tunnels.

[0382] 10. In Supplement 1,

[0383] The above IAB-node is connected to a first parent node, the above IAB-node is connected to a second parent node, the above first parent node is a node in the topology of the above first IAB-donor-CU, and the above second parent node is a node in the topology of the above second IAB-donor-CU, and

[0384] A method wherein the above traffic offloading request is included in a traffic offloading request message, the response of consent to the above traffic offloading is included in a traffic offloading request acknowledgment message, and the response of refusal to the above traffic offloading is included in a traffic offloading request refusal message.

[0385] 11. In the supplement to Section 10,

[0386] The above traffic offloading request message is:

[0387] A method comprising at least one of the identifier of a user device of a traffic offloading initiation node in an Xn interface (UE XnAP ID), the BAP address of an access IAB-node, the TNL address, one or more F1-C identification information, one or more F1-U tunnel identification information, IP header information of F1-C and / or F1-U tunnels, and QoS information of said F1-U tunnels.

[0388] 12. In Supplement 11,

[0389] If a traffic offloading request for the F1-C and / or F1-U tunnel is accepted, the traffic offloading request acknowledgment message is:

[0390] A method comprising at least one of the UE XnAP ID of the traffic offloading initiation node, the UE XnAP ID of the traffic offloading acceptance node, identification information of the F1-C and / or F1-U tunnel, a newly assigned TNL address for the DU of the access IAB-node, a BH RLC channel identifier on the link between the dual-link IAB-node configured for the F1-C and / or F1-U tunnel and the second parent node, the BAP address of the second parent node, a BAP routing identifier in the topology controlled by the second IAB-donor-CU, and the second BAP address of the IAB-node.

[0391] 13. In Supplement 11,

[0392] A method in which, when traffic offloading requests for all F1-C and F1-U tunnels are rejected, the traffic offloading request rejection message includes the UE XnAP ID of the traffic offloading initiation node.

[0393] 14. In Supplement 1,

[0394] The above IAB-node is connected to the above first parent node, the above IAB-node is connected to the above second parent node, the above first parent node is a node in the topology of the above first IAB-donor-CU, and the above second parent node is a node in the topology of the above second IAB-donor-CU, and

[0395] A method wherein the first IAB-donor-CU is a master node (MN), and the contents of the traffic offloading request and the contents of the response agreeing to the traffic offloading or the contents of the response rejecting the traffic offloading are taken as information elements (IEs) and included in the message of the S-NG-RAN node modification preparation procedure of XnAP.

[0396] 15. In Supplement 1,

[0397] The above IAB-node is connected to the above first parent node, and the above IAB-node is not connected to the above second parent node, the above first parent node is a node in the topology of the above first IAB-donor-CU, and the above second parent node is a node in the topology of the above second IAB-donor-CU, and

[0398] A method in which the contents of the traffic offloading request and the contents of the response agreeing to the traffic offloading or the contents of the response rejecting the traffic offloading are taken as information elements (IEs) and included in the message of the S-NG-RAN node addition preparation procedure of XnAP.

[0399] 16. In Supplement 15,

[0400] A method in which the above traffic offloading request is included in an auxiliary node addition request (S-NODE ADDITION REQUEST) message transmitted by the first IAB-donor-CU to the second IAB-donor-CU.

[0401] 17. In Supplement 15,

[0402] A method in which the response to consent to the above traffic offloading is included in an auxiliary node addition request acknowledgment (S-NODE ADDITION REQUEST ACKNOWLEDGE) message transmitted by the second IAB-donor-CU to the first IAB-donor-CU.

[0403] 18. In Supplement 1, the above method is:

[0404] The step of transmitting or receiving a duplicate path release request by the first IAB-donor-CU; and

[0405] A method further comprising the step of receiving or transmitting a duplicate path release request acceptance message by the first IAB-donor-CU.

[0406] 19. In Supplement 18,

[0407] A method wherein the above redundant path release request comprises the UE XnAP ID of the traffic offloading initiator node, the UE XnAP ID of the traffic offloading acceptor node, and the TNL address associated with F1-C which needs to release the redundant path, or User Plane Transport Layer Information (UP Transport Layer Information) of the F1-U tunnel which needs to release the redundant path.

[0408] 20. In Supplement 18,

[0409] When the MNs of the first IAB-donor-CU and the second IAB-donor-CU transmit duplicate path release requests,

[0410] A method in which the contents of the above duplicate path release request and the contents of the above duplicate path release request acceptance message are taken as IEs and included in the above S-NG-RAN node modification preparation procedure.

[0411] 21. In Supplement 1,

[0412] A method in which all redundant paths related to the IAB-node in the SN topology are released when performing the auxiliary base station node release (S-NG-RAN node Release) procedure of the IAB-node.

[0413] Method on the 2nd IAB-donor-CU side:

[0414] 1. A method for transmitting and receiving signals applicable to a second integrated access and backhaul node donor central unit (IAB-donor-CU), comprising:

[0415] Receiving a traffic offloading request transmitted by the first IAB-donor-CU; and

[0416] A method comprising the step of transmitting a response of consent to traffic offloading or a response of refusal to traffic offloading to the first IAB-donor-CU.

[0417] 2. In Supplement 1,

[0418] A method in which the above traffic offloading request includes a request to establish redundant paths for an IAB-node and / or descendant nodes of the said IAB-node.

[0419] 3. In Supplement 1, the above method is:

[0420] When the above IAB-node is already connected to a second parent node, the second IAB-donor-CU transmits a UE context modification request message to the second parent node to modify the user equipment (UE) context of the mobile terminal (MT) of the above IAB-node, and further includes the step of establishing at least one bearer.

[0421] The above second parent node is a node in the topology of the above second IAB-donor-CU, method.

[0422] 4. In Supplement 1, the above method is:

[0423] When the above IAB-node is not connected to the above second parent node, the above second IAB-donor-CU additionally includes the step of sending a UE context setup request message to the above second parent node to set up the UE context of the IAB's MT, and setting up at least one bearer.

[0424] The above second parent node is a node in the topology of the above second IAB-donor-CU, method.

[0425] 5. In Supplement 3 or Supplement 4, the method is:

[0426] A method further comprising the step of transmitting a second reconfiguration (RRCReconfiguration) message to the mobile terminal (MT) of the IAB-node by the second IAB-donor-CU, wherein the second RRCReconfiguration message includes BAP configuration information (bap-Config), and the BAP configuration information includes a second BAP address configured for the IAB-node.

[0427] 6. In Supplement 3 or Supplement 4, the method is:

[0428] For a second path required by the above IAB-node and / or a descendant node of the above IAB-node, the method further includes the step of performing BH RLC channel configuration and BAP sublayer routing entry configuration between the above IAB-node and the second IAB-donor-DU by the second IAB-donor-CU, and

[0429] The above second IAB-donor-DU is in the topology of the above second IAB-donor-CU, method.

[0430] 7. In Supplement 1,

[0431] The response to the consent for the above traffic offloading indicates that the traffic offloading request is accepted at least partially, and

[0432] A method in which the above traffic offloading request is accepted at least partially, which refers to redundant paths being established for some TNL-associated F1-Cs or some F1-U tunnels.

[0433] 8. In Supplement 1,

[0434] The above IAB-node is connected to a first parent node, and the above IAB-node is also connected to a second parent node, the above first parent node is a node in the topology of the above first IAB-donor-CU, and the above second parent node is a node in the topology of the above second IAB-donor-CU, and

[0435] A method wherein the above traffic offloading request is included in a traffic offloading request message, the response of consent to the above traffic offloading is included in a traffic offloading request acknowledgment message, and the response of refusal to the above traffic offloading is included in a traffic offloading request refusal message.

[0436] 9. In Supplement 8,

[0437] The above traffic offloading request message is:

[0438] A method comprising at least one of an identifier (UE XnAP ID) of a user device of a traffic offloading initiation node in an Xn interface, a BAP address of an access IAB-node, a TNL address, one or more F1-C identification information, one or more F1-U tunnel identification information, IP header information of F1-C and / or F1-U tunnels, and QoS information of F1-U tunnels.

[0439] 10. In Supplement 9,

[0440] If a traffic offloading request for the F1-C and / or F1-U tunnel is accepted, the traffic offloading request acknowledgment message is:

[0441] A method comprising at least one of the UE XnAP ID of the traffic offloading initiation node, the UE XnAP ID of the traffic offloading acceptance node, identification information of the F1-C and / or F1-U tunnel, a newly assigned TNL address for the DU of the access IAB-node, a BH RLC channel identifier on the link between the dual-link IAB-node configured for the F1-C and / or F1-U tunnel and the second parent node, the BAP address of the second parent node, a BAP routing identifier in the topology controlled by the second IAB-donor-CU, and the second BAP address of the IAB-node.

[0442] 11. In Supplement 9,

[0443] A method in which, when traffic offloading requests for all F1-C and F1-U tunnels are rejected, the traffic offloading request rejection message includes the UE XnAP ID of the traffic offloading initiation node.

[0444] 12. In Supplement 1,

[0445] The above IAB-node is connected to the above first parent node, and the above IAB-node is also connected to the above second parent node, the above first parent node is a node in the topology of the above first IAB-donor-CU, and the above second parent node is a node in the topology of the above second IAB-donor-CU, and

[0446] A method in which the first IAB-donor-CU is a master node (MN), and the contents of the traffic offloading request and the contents of the response agreeing to the traffic offloading or the contents of the response rejecting the traffic offloading are taken as information elements (IEs) and included in the messages of the S-NG-RAN node modification preparation procedure of XnAP.

[0447] 13. In Supplement 1,

[0448] The above IAB-node is connected to the above first parent node, and the above IAB-node is not connected to the above second parent node, the above first parent node is a node in the topology of the above first IAB-donor-CU, and the above second parent node is a node in the topology of the above second IAB-donor-CU, and

[0449] A method in which the contents of the traffic offloading request and the contents of the response agreeing to the traffic offloading or the contents of the response rejecting the traffic offloading are taken as information elements (IEs) and included in the messages of the S-NG-RAN node addition preparation procedure of XnAP.

[0450] 14. In Supplement 13,

[0451] A method in which the above traffic offloading request is included in an auxiliary node addition request (S-NODE ADDITION REQUEST) message transmitted by the first IAB-donor-CU to the second IAB-donor-CU.

[0452] 15. In Supplement 13,

[0453] A method in which the response to consent to the above traffic offloading is included in an auxiliary node addition request acknowledgment (S-NODE ADDITION REQUEST ACKNOWLEDGE) message transmitted by the second IAB-donor-CU to the first IAB-donor-CU.

[0454] 16. In Supplement 1, the above method is:

[0455] The step of receiving or transmitting a duplicate path release request by the second IAB-donor-CU; and

[0456] A method further comprising the step of transmitting or receiving a duplicate path release request acceptance message by the second IAB-donor-CU.

[0457] 17. In Supplement 16,

[0458] A method wherein the above redundant path release request comprises the UE XnAP ID of the traffic offloading initiator node, the UE XnAP ID of the traffic offloading acceptor node, and the TNL address associated with F1-C which needs to release the redundant path, or User Plane Transport Layer Information (UP Transport Layer Information) of the F1-U tunnel which needs to release the redundant path.

[0459] 18. In Supplement 16,

[0460] When the MNs of the first IAB-donor-CU and the second IAB-donor-CU transmit duplicate path release requests,

[0461] A method in which the contents of the above duplicate path release request and the contents of the above duplicate path release request acceptance message are taken as IEs and included in the above S-NG-RAN node modification preparation procedure.

[0462] 19. In Supplement 1,

[0463] A method in which all redundant paths related to the IAB-node in the SN topology are released when performing the auxiliary base station node release (S-NG-RAN node Release) procedure of the IAB-node.

[0464] Method on the dual-connection IAB-node side:

[0465] 1. A method for transmitting and receiving signals applicable to an IAB-node, wherein the IAB-node is connected to a first parent node, and the IAB-node is already connected to or will be connected to a second parent node, the first parent node is a node in the topology of a first IAB-donor-CU, and the second parent node is a node in the topology of a second IAB-donor-CU.

[0466] The above method is:

[0467] The step of receiving a first RRC reconstruction message transmitted by the first IAB-donor-CU; and

[0468] The method includes the step of transmitting an RRC reconstruction completion message to the first IAB-donor-CU,

[0469] The above first RRC reconfiguration message is generated in response to the consent for traffic offloading transmitted by the second IAB-donor-CU to the first IAB-donor-CU, and

[0470] The first RRC reconfiguration message includes at least one TNL address assigned to a DU of the IAB-node, and the TNL address is anchored to a second IAB-donor-DU in the topology of the second IAB-donor-CU;

[0471] A method in which the above RRC reconstruction completion message is used to indicate that the above IAB-node has received the above first RRC reconstruction message.

[0472] 2. In Supplement 1, the above method is:

[0473] A step of receiving a second RRC reconfiguration message transmitted by the second IAB-donor-CU by the IAB-node - the second RRC reconfiguration message includes BAP configuration information (bap-Config), and the BAP configuration information includes a second BAP address configured for the IAB-node - ; and

[0474] The method further includes the step of transmitting an RRC reconstruction completion message by the above IAB-node to the above second IAB-donor-CU,

[0475] A method in which the above RRC reconstruction completion message is used to indicate that the above IAB-node has received the above second RRC reconstruction message.

[0476] 3. In Supplement 2, the above method is:

[0477] A method further comprising the step of associating the second BAP address with a master cell group (MCG) / auxiliary cell group (SCG) or a master node (MN) / auxiliary node (SN) by the above IAB-node.

[0478] 4. In Supplement 3,

[0479] If the second RRCReconfiguration message carrying the second BAP address received by the IAB-node is from the MCG or received via signaling radio bearer (SRB) 1, the second BAP address is associated with the MCG or the MN;

[0480] A method in which, if the second RRCReconfiguration message carrying the second BAP address received by the IAB-node is from the SCG or received via SRB3, the second BAP address is associated with the SCG or the SN.

[0481] 5. In Supplement 1,

[0482] The bap configuration information element (bap-Config IE) of the first RRC reconfiguration message includes a field used to indicate a second BAP address configured for the IAB-node; or

[0483] A method in which the bap address field within the BAP configuration information element (bap-Config IE) of the first RRC reconfiguration message includes a list, and each entry in the list is a BAP address and its associated information.

[0484] Method on the descendant node side:

[0485] 1. A method for transmitting and receiving signals applicable to a descendant node of an IAB-node, wherein the IAB-node is connected to a first parent node, and the IAB-node is already connected to or will be connected to a second parent node, the first parent node is a node in the topology of a first IAB-donor-CU, and the second parent node is a node in the topology of a second IAB-donor-CU.

[0486] The above method is:

[0487] The step of receiving a first RRC reconstruction message transmitted by the first IAB-donor-CU; and

[0488] The method includes the step of transmitting an RRC reconstruction completion message to the first IAB-donor-CU,

[0489] The above first RRC reconfiguration message is generated in response to the consent for traffic offloading transmitted by the second IAB-donor-CU to the first IAB-donor-CU, and

[0490] The first RRC reconstruction message includes at least one TNL address assigned to the DU of the descendant node, and the TNL address is anchored to the second IAB-donor-DU in the topology of the second IAB-donor-CU;

[0491] A method in which the above RRC reconstruction completion message is used to indicate that the descendant node has received the first RRC reconstruction message.

Claims

Claim 1 A device for transmitting and receiving signals applicable to a first integrated access and backhaul node donor central unit (IAB-donor-CU), comprising a first controller, wherein the first controller is configured to: transmit a traffic offload request to a second IAB-donor-CU; and receive a reply of consent to the traffic offload or a reply of refusal to the traffic offload transmitted by the second IAB-donor-CU, wherein the IAB node is connected to a first parent node, and the IAB node is connected to or will be connected to a second parent node, wherein the first parent node is a node in the topology of the first IAB-donor-CU, and the second parent node is a node in the topology of the second IAB-donor-CU, wherein the traffic offload request is included in a traffic offload request message, the reply of consent to the traffic offload is included in a traffic offload request acknowledge message, and the reply of refusal to the traffic offload is a traffic offload request refusal. Device included in the message. Claim 2 A device according to claim 1, wherein the first controller is further configured to transmit a first RRC reconfiguration message to an IAB node and / or a descendant IAB node of the IAB node in response to consent to the traffic offload, and the first RRC reconfiguration message includes at least one TNL address assigned to the IAB node and / or the descendant node of the IAB node, and the TNL address is anchored to a second IAB-donor-DU within the topology of the second IAB-donor-CU. Claim 3 delete Claim 4 A device according to claim 1, wherein the traffic offload request includes a request to establish a redundant path for the IAB node and / or the descendant nodes of the IAB node. Claim 5 In paragraph 4, the first controller is further configured to perform BAP routing identifier mapping for the IAB node by the first IAB-donor-CU in response to the reply of consent for the traffic offload. Claim 6 A device according to claim 1, wherein the reply of consent to the traffic offload indicates that the traffic offload request is at least partially accepted, and that the traffic offload request is at least partially accepted indicates that redundant paths are established for some TNL-associated F1-Cs or for some F1-U tunnels. Claim 7 delete Claim 8 The device according to claim 1, wherein the traffic offload request message comprises: an identifier (UE XnAP ID) of a user device of a traffic offload initiation node at an Xn interface, a TNL address, one or more F1-C identification information, one or more F1-U tunnel identification information, and at least one of QoS information of the F1-U tunnels. Claim 9 In claim 8, when a traffic offload request for F1-C and / or F1-U tunnels is accepted, the traffic offload request acknowledgment message comprises: at least one of the following: a UE XnAP ID of the traffic offload initiating node, a UE XnAP ID of the traffic offload accepting node, identification information of the F1-C and / or F1-U tunnels, a newly assigned TNL address for the IAB node, a BH RLC channel identifier on the link between the second parent node and the dual-linked IAB node configured for the F1-C and / or F1-U tunnels, a BAP address of the second parent node, and a BAP routing identifier in the topology controlled by the second IAB-donor-CU. Claim 10 In paragraph 8, a device in which, when traffic offload requests for all F1-C and F1-U channels are denied, the traffic offload request denial message includes the UE XnAP ID of the traffic offload initiation node. Claim 11 delete Claim 12 A device according to claim 1, wherein the first controller is further configured to: transmit or receive a duplicate path release request to the first IAB-donor-CU; and receive or transmit a duplicate path release request acceptance message to the first IAB-donor-CU. Claim 13 In paragraph 12, the device comprises, wherein the redundant path release request includes the UE XnAP ID of the traffic offload initiating node, the UE XnAP ID of the traffic offload receiving node, and the TNL address associated with the F1-C that needs to be released from the redundant path, or User Plane Transport Layer Information (UP Transport Layer Information) of the F1-U channel that needs to be released from the redundant path. Claim 14 A device according to claim 1, wherein when performing the auxiliary base station node release (S-NG-RAN node Release) process of the IAB node, all redundant paths related to the IAB node in the SN topology are released. Claim 15 A device for transmitting and receiving signals applicable to a second integrated access and backhaul node donor central unit (IAB-donor-CU), comprising a second controller, wherein the second controller is configured to: receive a traffic offload request transmitted by a first IAB-donor-CU; and transmit a reply of consent to traffic offload or a reply of refusal to traffic offload to the first IAB-donor-CU, wherein the IAB node is connected to a first parent node, and the IAB node is connected to or will be connected to a second parent node, wherein the first parent node is a node in the topology of the first IAB-donor-CU, and the second parent node is a node in the topology of the second IAB-donor-CU, wherein the traffic offload request is included in a traffic offload request message, the reply of consent to traffic offload is included in a traffic offload request acknowledge message, and the reply of refusal to traffic offload is included in a traffic offload request refusal message. Claim 16 In paragraph 15, the device, wherein the traffic offload request includes a request to establish a redundant path for an IAB node and / or a descendant node of the IAB node. Claim 17 A device for transmitting and receiving signals applicable to an IAB node, wherein the IAB node is connected to a first parent node, and the IAB node is already connected to or will be connected to a second parent node, the first parent node is a node in the topology of a first IAB-donor-CU, and the second parent node is a node in the topology of a second IAB-donor-CU, and the device comprises a third controller, wherein the third controller is configured to: receive a first RRC reconstruction message transmitted by the first IAB-donor-CU; and transmit an RRC reconstruction complete message to the first IAB-donor-CU, wherein the first RRC reconstruction message comprises at least one TNL address assigned to the IAB node, the TNL address is anchored to a second IAB-donor-DU in the topology of the second IAB-donor-CU; and the RRC reconstruction complete message is used to indicate that the IAB node has received the first RRC reconstruction message. Claim 18 In paragraph 17, the third controller: receives, by the IAB node, a second RRC reconfiguration message transmitted by the second IAB-donor-CU, wherein the second RRC reconfiguration message includes BAP configuration information (bap-Config), and the BAP configuration information includes a second BAP address configured for the IAB node; additionally configured to transmit an RRC reconfiguration completion message by the IAB node to the second IAB-donor-CU, wherein the RRC reconfiguration completion message is used to indicate that the IAB node has received the second RRC reconfiguration message. Claim 19 In paragraph 18, the third controller is further configured to associate the second BAP address with a master cell group (MCG) / secondary cell group (SCG) or a master node (MN) / secondary node (SN) by the IAB node, a device. Claim 20 A device according to claim 18, wherein if a second RRCReconfiguration message carrying the second BAP address received by the IAB node is from an MCG or received via a signaling radio bearer (SRB) 1, the second BAP address is associated with the MCG or MN; and if a second RRCReconfiguration message carrying the second BAP address received by the IAB node is from an SCG or received via SRB3, the second BAP address is associated with the SCG or SN. Claim 21 In paragraph 2, the first controller is further configured to add the new TNL address to the F1-C association of the DU of the first IAB-donor-CU and the IAB node and / or the descendant node of the IAB node when the new TNL address is assigned. Claim 22 In paragraph 5, the first controller is further configured to support routing of a second path and BH RLC channel mapping by performing BH RLC channel configuration and BAP sublayer routing entry configuration between the IAB node and the descendant node of the IAB node by the first IAB-donor-CU.

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