Method and system for exchanging information in an integrated access backhaul system

Abstract

Methods, apparatuses, and systems for reducing packet loss in a wireless system during handover, where one or more user equipment or mobile terminals are connected to an integrated access backhaul node. The present disclosure relates to continuous uplink (UL) and maintaining service continuity in an integrated access backhaul (IAB) system.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to wireless communication. BACKGROUND

[0002] Mobile communication technology is pushing the world towards a closely connected and networked society. The rapid growth of mobile communications and advances in technology lead to greater demands for capacity and connectivity. Other aspects, such as energy consumption, device cost, spectrum efficiency, and latency, are also important to meet the needs of various communication scenarios. Various technologies are currently being discussed, including new methods that provide higher quality of service, longer battery life, and improved performance. SUMMARY

[0003] This patent document describes techniques for communicating, among other things, in an integrated access backhaul (IAB) deployment of new radio (NR).

[0004] The following aspects can be preferred to be implemented in various embodiments.

[0005] In an aspect, one or more IAB nodes are communicatively coupled to a first parent node or a second parent node and one or more child nodes, wherein the parent node is communicatively coupled to a first IAB donor central unit (CU).

[0006] In an aspect, one or more IAB nodes receive a RRCreconfiguration message, or a stop indication, or a handover indication. In yet another aspect, the IAB node sends a stop indication or a handover indication to a child IAB node, wherein the stop indication or the handover indication indicates that the child node should stop data forwarding. In yet another embodiment, the IAB node is an IAB donor central unit (CU).

[0007] In an aspect, one or more IAB nodes receive a stop indication in an F1AP message, wherein the F1AP message includes a RRCreconfiguration message, and the stop forwarding user equipment (UE) data packets.

[0008] In an aspect, one or more IAB nodes include a flag in a BAP header of a user equipment (UE) packet, and send the UE packet to a next hop, wherein the flag indicates that the next hop ignores the BAP header or selects any next hop or selects any egress backhaul (BH) RLC channel to deliver the packet.

[0009] In an aspect, the one or more IAB nodes transmit uplink (UL) delivery status information to at least one or more child nodes. In a further aspect, the UL delivery status information includes a sequence number (SN) of one or more packets received from one of the one or more child nodes, wherein the one or more packets have not been transmitted to a first parent node or have not been acknowledged as received by the first parent node. In a further aspect, the UL delivery status information is transmitted via a BAP-sublayer control PDU or a BAP-sublayer data unit or a RLC-sublayer control PDU. In a further aspect, the UL delivery status information includes at least one of a RLC SN, a RLC channel ID or a Logical Channel (LC) ID, a Backhaul (BH) RLC channel ID or a BAP-sublayer SN. In a further aspect, the one or more IAB nodes transmit one or more data packets that need to be retransmitted to at least one of the one or more child nodes, wherein the one or more data packets contain at least one of a BAP address of a source IAB node, a BAP address of an access node and a flag in a BAP-subheader. In a further aspect, a backhaul RLC channel used to transmit the one or more data packets is configured by the donor CU.

[0010] In an aspect, the one or more IAB nodes receive a UL transmission status from a second IAB donor CU, wherein the UL transmission status is transmitted after the SN transmission message is received by the second IAB donor CU and retransmit packets in accordance with the UL transmission status. In a further embodiment, the UL transmission status contains at least one of a reception status of a UL PDCP SDU and a UL COUNT value of a first missing UL SDU.

[0011] In an aspect, the one or more IAB nodes include a flag in a GTP-U header of one or more packets, wherein the flag indicates that the packets need to be forwarded to a first IAB donor Central Unit (CU) and transmit the one or more packets to a next hop.

[0012] In another aspect, the one or more IAB nodes transmit an end marker to a second IAB donor CU via a GTP-U layer or a FlAP message after receiving a stop indication in a FlAP message. In a further aspect, the second IAB donor CU transmits the end marker to a first IAB donor CU.

[0013] In yet another aspect, the donor CU sends a stop indication to one or more IAB nodes in a FlAP message, wherein the FlAP message includes a RRCreconfiguration message, wherein the stop indication indicates that the one or more IAB nodes stop forwarding of user equipment (UE) data packets.

[0014] In yet another embodiment, the IAB node receives uplink (UL) delivery status information from one or more parent IAB nodes. In yet another embodiment, the UL delivery status information includes a sequence number (SN) of one or more packets received from one of the one or more child nodes, wherein the one or more packets have not been transmitted to a first parent node or have not been acknowledged as received by the first parent node. In another embodiment, the UL delivery status information is transmitted via a BAP sublayer control PDU or a BAP sublayer data PDU or a RLC sublayer control PDU. In yet another embodiment, the UL delivery status information includes at least one of a RLC SN, a RLC channel ID or a Logical Channel (LC) ID, a Backhaul (BH) RLC channel ID or a BAP sublayer SN.

[0015] In an aspect, the IAB node receives one or more data packets from one or more IAB nodes that need to be retransmitted, wherein the one or more data packets contain at least one of a BAP address of a source IAB node, a BAP address of an access node, and a flag in a BAP subheader. In yet another aspect, a backhaul RLC channel for the one or more data packets is configured by the donor CU.

[0016] In an aspect, a second IAB donor CU sends a UL transmission status to one or more IAB nodes, wherein the UL transmission status is sent after the second IAB donor CU receives a SN transmission message from a first IAB donor CU, wherein the one or more IAB nodes are configured to determine which packets need to be retransmitted based on the UL transmission status. In yet another aspect, the UL transmission status contains at least one of a reception status of a UL PDCP SDU and a UL COUNT value of a first missing UL SDU.

[0017] In yet another aspect, the first IAB donor CU receives one or more packets from one or more IAB nodes, the one or more packets including a flag in a GTP-U header, wherein the flag indicates that the packets need to be forwarded to a first IAB donor Central Unit (CU).

[0018] In another aspect, the second IAB donor CU receives an end marker via a GTP-U layer or Fl AP message, where the end marker can be used by the second IAB donor CU to stop forwarding one or more packets to the first IAB donor CU. In yet another aspect, the second IAB donor CU sends the end marker to the first IAB donor CU.

[0019] In aspects of the disclosure, the sending and receiving of messages are performed by various devices, including MTs, UEs, IAB nodes (e.g., access, migration, descendant, or ancestor), and IAB donors.

[0020] These and other aspects are described in the disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Embodiments of IAB deployment in a mobile vehicle are shown.

[0022] Figure 2 Embodiments of IAB topology are shown.

[0023] Figure 3 IAB topology performing IAB node handover is shown.

[0024] Figure 4 IAB topology performing IAB node handover is shown.

[0025] Figure 5 Embodiments of managing UL data transmission for descendant nodes or UEs are shown.

[0026] Figure 6 Embodiments of managing UL data transmission for descendant nodes or UEs are shown.

[0027] Figure 7 Another embodiment of managing packet retransmission is shown.

[0028] Figure 8 Embodiments of a node determining packets to be retransmitted are shown.

[0029] Figure 9 Embodiments of packet retransmission are shown.

[0030] Figure 10 Embodiments of identifying packets that need to be forwarded from a target to a source donor are shown.

[0031] Figure 11 An example of a wireless communication system to which techniques according to one or more embodiments of the present technology can be applied is shown.

[0032] Figure 12is a block diagram representation of a part of a wireless base station to which the techniques according to one or more embodiments of the present technology can be applied. DETAILED DESCRIPTION

[0033] The present disclosure relates to wireless systems. More specifically, the present disclosure relates to reducing packet loss during handover in IAB deployments.

[0034] For example, an Integrated Access and Backhaul (IAB) system supports wireless backhaul by deploying a New Radio (NR) cell, thereby reducing the need for wired transport infrastructure.

[0035] The terminating node of the NR backhaul network on the network side is often referred to as an IAB donor, which represents a gNB, which is a logical node with additional functionality to support IAB. The IAB node supports gNB Distributed Unit (gNB-DU) functionality, which allows NR access User Equipment (UE) and a next-hop IAB node. The IAB node also supports IAB-MT functionality, which allows connection to another IAB node or gNB-DU of an IAB donor.

[0036] In one example, as shown in Figure 1 A movable vehicle, such as a high-speed train 101, has several passengers with one or more Mobile Terminals (MTs) or User Equipments (UEs) 103-106. The UEs 103-106 are wirelessly connected to an IAB node 102, and the IAB node 102 is in turn connected to a donor node or parent IAB node 107 or 108. As the high-speed train moves, handover between the parent IAB nodes occurs. The UEs 103-106 access the network via the IAB node 102, and the IAB node 102 accesses the network via the parent IAB node. Here, it should be understood that the use of the terms UE and MT are not mutually exclusive, and either term should be assumed to refer to either an MT or a UE. It should also be understood that the parent IAB node is understood to be included in the term “base station”. It should be understood that although a movable vehicle has been discussed, the techniques disclosed herein are also applicable to static IAB nodes, which can want to perform migration due to load balancing or due to Back Haul Radio Link Failure (BH RLF).

[0037] As train 101 passes, the relative positions of UEs 103 to 106 and IAB node 102 will change very little. However, as train 101 moves forward, the relative positions of IAB node 102 and each IAB donor will change frequently.

[0038] Therefore, this disclosure provides a system and method for performing a switchover of IAB node 102. This reduces signaling overhead and improves service continuity.

[0039] Figure 2 The IAB topology is shown. Parent nodes 201 and 202 have IAB-DU functionality and provide NR access to IAB node 203. IAB node 203 functions as both an IAB MT and an IAB DU. IAB node 203 can connect to parent nodes 201 and 202 as an IAB MT and also provides access to child nodes 204 to 206 as an IAB DU. Child nodes 204 to 206 have IAB MT functionality. It can be understood that any node in the topology can act as a donor or terminal, provided it is designed to have that functionality.

[0040] Figure 3 The IAB topology for performing IAB node handover is shown. UE 302 is wirelessly coupled to IAB node 304, and IAB node 304 is wirelessly coupled to IAB node 306. UE 308 is coupled to IAB node 306. It should be understood that any number of UEs or MTs can be coupled to any IAB node.

[0041] As shown by arrow 322, IAB node 306 migrates from IAB node 314 to IAB node 312. IAB node 314 is coupled to IAB donorDU 318, and IAB node 312 is coupled to IAB donorDU 316. Both IAB donors 318 and 316 are coupled to IAB donor CU.

[0042] Figure 4 The IAB topology for performing IAB node switching is shown. Figure 4 and Figure 3 The difference is that there is a second IABdonor CU.

[0043] UE 402 is wirelessly coupled to IAB node 404, and IAB node 404 is wirelessly coupled to IAB node 406. UE 408 is coupled to IAB node 406. It should be understood that any number of UEs or MTs can be coupled to any IAB node.

[0044] As indicated by arrow 422, IAB node 406 migrates from IAB node 414 to IAB node 412. IAB node 414 is coupled to IAB donor DU 418, and IAB node 412 is coupled to IAB donor DU 424. IAB donors 418 and 416 are both coupled to different IAB donor CUs. Figure 4 In this case, IAB node 406 migrates not only between IAB nodes, but also between IABdonor CUs.

[0045] It should be understood that the disclosed topology is merely exemplary. Any number of nodes, UEs, or donors can exist in an IAB deployment.

[0046] The disclosed topology applies to the embodiments disclosed herein.

[0047] Figure 5 An embodiment of managing UL data transmission for a descendant node or UE is illustrated. In step 502, the IAB node receives an RRCreconfiguration message, either a stop indication or a handover indication. In step 504, the IAB node that received the message sends the stop indication or handover indication to the child node. It should be understood that the child node can be another IAB node, a UE, or an MT. In step 506, the node that received the stop indication or handover indication stops forwarding data to the IAB node. In one embodiment, the IAB node is an IAB donor central unit (CU).

[0048] In one embodiment, the access or intermediate IAB node buffers data packets received from the UE and transmits the buffered packets on the target path. In one embodiment, the IAB node begins buffering data packets upon receiving a stop indication (or handover initiation indication) from its parent node, and sends a stop indication to the child MT upon receiving a stop indication from its parent node. In one embodiment, the migration IAB node sends a stop indication upon receiving a HO CMD.

[0049] In one embodiment, UL transmission resumes after the IAB node receives the updated F1-U UL mapping configuration and upon receiving a recovery indication (or handover completion indication) from the parent node. In another embodiment, this option is used when the updated F1-U UL mapping configuration is sent via the HO CMD, wherein the IAB node sends a recovery indication to the child MT upon receiving the recovery indication from the parent node, and the migrating IAB node sends a recovery indication when the target path is ready.

[0050] Figure 6An embodiment of managing UL data transmission for a descendant node or UE is illustrated. In step 602, the IAB node receives a stop indication or handover indication in an F1AP message. In one embodiment, the F1AP message includes an RRC reconfiguration message. In step 604, the IAB stops forwarding UE data packets. In one embodiment, DL RRC MESSAGETRANSFER is an example of an F1AP message.

[0051] In one embodiment, the UE will send RRCreconfigurationcomplete after receiving the HO CMD and using the new encryption key. In another embodiment, the migration IAB node can still connect to the source parent node, and the IAB node will stop forwarding the RRCreconfigurationcomplete message and the packets encrypted with the new key on the source path; that is, it will stop UL data forwarding and buffer the data packets received by the UE to avoid delivering the RRCreconfigurationcomplete / SCTP / F1 setup message and the UE packets encrypted with the new key to the source donor CU. In one embodiment, the access IAB node stops UL data forwarding for the corresponding UE upon receiving a stop indication in the DL RRC MESSAGE TRANSFER message, which includes the HO CMD for the UE.

[0052] Figure 7 Another embodiment for managing packet retransmission is illustrated. In step 702, a flag from the Backhaul Adaptation Protocol (BAP) header is included in the UE packet. In step 704, the UE packet is sent to the next hop. This flag instructs the next hop to either ignore the BAP header or select any next hop or any egress Backhaul (BH) Radio Link Control (RLC) channel to deliver the UE packet.

[0053] In one embodiment, after an IAB node migrates from one parent node to another, the BAP address and BAP route ID change, and the IAB node and donorDU on the destination path cannot recognize the BAP route ID contained in the BAP header of the retransmitted packets, and may drop these packets. In one embodiment, to solve this problem, the migrating IAB node includes a flag in the BAP header of the retransmitted packets, and if the flag is present, the parent IAB node either ignores the BAP header or selects any next hop or any egress BH RLC channel to deliver the packets.

[0054] Figure 8An embodiment of a node determining packets to be retransmitted is illustrated. In step 802, the IAB node sends UL delivery status information to the child node. In one embodiment, the UL delivery status information includes the sequence number (SN) of packets from the child node that have not yet been sent to or acknowledged by the parent node of the IAB node. In one embodiment, the UL delivery status information is sent via a BAP sublayer control PDU, a BAP sublayer data PDU, or an RLC sublayer control PDU. In one embodiment, the UL delivery status information includes at least one of an RLC SN, an RLC channel ID or a logical channel (LC) ID, a backhaul (BH) RLC channel ID, or a BAP sublayer SN. In step 804, the IAB node sends the packets that need to be retransmitted to the child node. In one embodiment, the packets contain at least the BAP address of the source IAB node, the BAP address of the access node, and flags in the BAP subheader.

[0055] In one embodiment, the IAB access IAB node determines the packets that need to be retransmitted. The migration / descendant IAB node sends UL delivery status information (e.g., the SN of packets received from the child MT that have not been acknowledged or sent) to the child MT. Upon receiving the UL delivery status information, the child IAB node also sends the SN of packets received from its child MT that have not been acknowledged by RLC ACK to its child MT. The UL delivery status information may be sent via the BAP layer (e.g., BAP control PDU) or the RLC layer (e.g., RLC control PDU) and includes at least one of the following: the RLC SN in the ingress link; the RLC channel ID or LCID; and the BAP layer SN.

[0056] In one embodiment, the migrating / descendant IAB node sends the SN and packets that need to be retransmitted on the destination path to the descendant node. The BAP address of the access IAB node is also included in the BAP header. In one embodiment, a retransmission flag needs to be included in the BAP header. Any BH RLC channel or a channel of a specific implementation or a channel configured via the CU can be used.

[0057] Figure 9 An embodiment of packet retransmission is illustrated. In step 902, the IAB node receives the UL transmission status from the donor IAB. In one embodiment, the UL transmission status is sent after the IAB donor CU receives the SN transmission message. In step 904, the IAB node retransmits packets based on the UL transmission status. In one embodiment, the UL transmission status includes at least one of the reception status of the UL PDCP SDU and the UL COUNT value of the first lost UL SDU.

[0058] In one embodiment, after receiving an SN status transmission message (which may contain the status of the PDCP SDU and the UL COUNT value for each UE DRB) from the source donor CU, the target donor CU sends the UL transmission status to the access IAB node. The access IAB node can determine which packets need to be retransmitted based on the UL transmission status received from the target donor CU.

[0059] Figure 10 An embodiment is illustrated for identifying packets that need to be forwarded from the destination to the source donor. In step 1002, the IAB node causes one or more packets to include a flag in their GTP-U header. In one embodiment, this flag indicates that the packet needs to be forwarded to the source donor, such as a specific donor CU. In step 1004, the IAB node sends the packet to the next hop.

[0060] Figure 11 An embodiment for identifying packets that need to be forwarded is illustrated. In step 1102, the IAB node receives a stop indication from the F1AP message. In step 1104, the IAB node sends an end marker to the target donor CU via the GTP-U layer or the F1AP message. In one embodiment, the target IAB donor (CU) sends the end marker to the source IAB donor (CU).

[0061] In one embodiment, the target donor CU identifies packets that need to be forwarded to the source donor CU via an end marker. The UE applies a new encryption key after receiving the HO CMD, and the access IAB node sends an end marker after receiving a DL RRC MESSAGETRANSFER message (which includes the HO CMD for the UE). The target donor CU forwards packets received from the migration / descendant node to the S-donor CU until it receives the end marker. In one embodiment, the donor CU should be aware of the end marker. In one embodiment, the end marker is sent per UE bearer or per UE. In one embodiment, the T-donor CU also sends the end marker to the S-donor CU, and then the S-donor CU sends an SN status transmission message (which includes the UL transmission status) to the T-donor CU upon receiving the end marker.

[0062] In one embodiment, a stop / resume instruction is sent to the child IAB-MT via the IAB node, and UL data transmission between the descendant node and the UE continues during migration. In another embodiment, by including a stop instruction in the DL RRC MESSAGE TRANSFER message, UL data transmission between the descendant node and the UE continues during migration.

[0063] In one embodiment, the BAP address and BAP route ID change after the migration, and the access IAB node causes the packet's BAP header to include a flag, wherein the IAB node ignores the BAP header, and if the flag is present, selects either any next hop or any egress BH RLC channel to deliver the packet.

[0064] In one embodiment, the access IAB node determines which packets need to be retransmitted or sent by receiving UL delivery status information (e.g., the SN of packets received from the child MT that have not been acknowledged or sent) from the migrating IAB node and / or intermediate nodes. In another embodiment, the access IAB node determines which packets need to be retransmitted or sent by sending the SN and the packets that need to be retransmitted on the destination path to the child IAB-MT. In yet another embodiment, the access IAB node determines which packets need to be retransmitted or sent by including the BAP address of the source IAB node or the BAP address of the access IAB node in the BAP header. In one embodiment, a retransmission flag may be included in the BAP header. In one embodiment, the access IAB node determines which packets need to be retransmitted or sent, wherein the donor CU configures traffic mapping for packets that need to be retransmitted via F1AP messages. In one embodiment, the access IAB node determines which packets need to be retransmitted or sent after receiving an SN status transmission message (containing the status of the PDCP SDU and the UL COUNT value for each UE DRB) from the source donor CU, and the destination donor CU sends the UL transmission status to the access IAB node via F1.

[0065] In one embodiment, the target donor CU identifies which packets need to be forwarded to the source donor CU by including a flag / end marker in the GTP-U header, or the T-donor CU sends an end marker to the S-donor CU so that upon receiving the end marker, the source donor CU knows that there is no more data to be forwarded from the target donor CU. In one embodiment, the access IAB node includes a flag / end marker in the GTP-U header.

[0066] It should be understood that while some embodiments describe sending certain data to nodes in an IAB deployment, this disclosure contemplates receiving and further transmitting. For example, when describing an IAB node sending a piece of data to a UE, it should be understood that there are any number of child IAB nodes between the IAB node sending the data and the UE. It should be understood that those IAB nodes also transmit the data. This also applies to any node along the path from the IAB node sending the data to the IAB donor CU.

[0067] Figure 11An example of a wireless communication system 1100 to which one or more embodiments of the present technology may be applied is shown. The wireless communication system 1100 may include one or more base stations (BS) 1105a, 1105b, one or more wireless devices 1110a, 1110b, 1110c, 1110d, and a core network 1125. Base stations 1105a, 1105b may provide wireless services to wireless devices 1110a, 1110b, 1110c, and 1110d in one or more wireless sectors. In some embodiments, base stations 1105a, 1105b include directional antennas that generate two or more directional beams to provide wireless coverage in different sectors. It should be understood that references... Figures 1 to 4 A base station can be a series of IAB nodes.

[0068] Core network 1125 can communicate with one or more base stations 1105a, 1105b. Core network 1125 provides connectivity with other wireless communication systems and wired communication systems. Core network 1125 may include one or more service subscription databases to store information related to subscribed wireless devices 1110a, 1110b, 1110c, and 1110d. First base station 1105a can provide wireless services based on a first wireless access technology, while second base station 1105b can provide wireless services based on a second wireless access technology. Depending on the deployment, base stations 1105a and 1105b can be co-located or installed separately in the field. Wireless devices 1110a, 1110b, 1110c, and 1110d can support a variety of different wireless access technologies. The technologies and embodiments described herein can be implemented by base stations of the wireless devices described herein.

[0069] Figure 12 This is a block diagram representation of a portion of a wireless base station to which one or more embodiments of the present technology may be applied. The wireless base station 1205, such as a base station or wireless device (or UE) or MT, may include processor electronics 1210, such as a microprocessor implementing one or more of the wireless technologies presented herein. The wireless base station 1205 may include transceiver electronics 1215 for transmitting and / or receiving wireless signals via one or more communication interfaces, such as antenna 1220. The wireless base station 1205 may include other communication interfaces for transmitting and receiving data. The wireless base station 1205 may include one or more memories (not explicitly shown) configured to store information such as data and / or instructions. In some embodiments, processor electronics 1210 may include at least a portion of transceiver electronics 1215. In some embodiments, at least some of the disclosed technologies, modules, or functions are implemented using the wireless base station 1205. In some embodiments, the wireless base station 1205 may be configured to perform the methods described herein.

[0070] It should be understood that this document discloses techniques that can be implemented in various embodiments of IAB deployment. The disclosed and other embodiments, modules, and functional operations described in this document can be implemented in digital electronic circuits, or in computer software, firmware, or hardware (including the structures disclosed in this document and their structural equivalents), or in a combination of one or more of these. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded in a computer-readable medium for execution by or control of the operation of a data processing apparatus. A computer-readable medium can be a combination of a machine-readable storage device, a machine-readable storage substrate, a storage device, a substance that implements machine-readable propagating signals, or a combination of one or more of these. The term "data processing apparatus" includes all means, devices, and machines for processing data, including, for example, a programmable processor, a computer, or a plurality of processors or computers. In addition to hardware, the apparatus may include code that creates an execution environment for the computer program in question, for example, code constituting processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of these. Propagating signals are artificially generated signals, such as machine-generated electrical, optical, or electromagnetic signals, generated to encode information for transmission to a suitable receiver device.

[0071] Computer programs (also known as programs, software, software applications, scripts, or code) can be written in any programming language, including compiled or interpreted languages, and can be deployed in any form, including as standalone programs or as modules, components, subroutines, or other units suited to a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored as a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), as a single file dedicated to the program in question, or as multiple collaborative files (e.g., a file storing one or more modules, subroutines, or code sections). Computer programs can be deployed to execute on a single computer or on multiple computers located in one place or distributed across multiple locations and interconnected via a communication network.

[0072] The processes and logic flows described in this document can be executed by one or more programmable processors, which execute one or more computer programs to perform functions by manipulating input data and generating output. The processes and logic flows can also be executed by dedicated logic circuitry, and the devices can be implemented as dedicated logic circuitry, such as field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).

[0073] For example, processors suitable for executing computer programs include general-purpose microprocessors and special-purpose microprocessors, as well as any one or more processors in any kind of digital computer. Typically, the processor receives instructions and data from read-only memory or random access memory, or both. The basic components of a computer are a processor for executing instructions and one or more storage devices for storing instructions and data. Typically, a computer will also include, or be operatively coupled to, one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, to receive data from, transfer data to, or both of these mass storage devices. However, a computer does not need to have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and storage devices, including, for example, semiconductor storage devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD-ROMs and DVD-ROMs. The processor and memory may be supplemented or incorporated therein by dedicated logic circuitry.

[0074] While this patent document contains numerous details, these details should not be construed as limiting any invention or the scope of the claims, but rather as descriptions of features characteristic of specific embodiments of a particular invention. Certain features described in this patent document within the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually in multiple embodiments or in any suitable sub-combination. Furthermore, although some features may be described above as functioning in certain combinations, and even initially claimed in this way, in some cases, one or more features from a claimed combination may be removed from that combination, and the claimed combination may be for sub-combinations or variations thereof.

[0075] Similarly, although operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring such operations to be performed in the specific order or sequence shown, or requiring all shown operations to obtain the desired result. Furthermore, the separation of various system components in the embodiments described in this patent document should not be construed as requiring such separation in all embodiments.

[0076] Only some implementation methods and examples are described, and other implementation methods, enhancements and variations can be achieved based on the content described and shown in this patent document.

Claims

1. An information transmission method, comprising: The Integrated Access Backhaul (IAB) node sends uplink UL delivery status information to the child nodes. This UL delivery status information includes sequence numbers (SNs) of one or more packets received from one of the child nodes, wherein the one or more packets have not yet been sent to the parent node of the IAB node or have not yet been acknowledged as received by the parent node of the IAB node; and The IAB node sends one or more packets that need to be retransmitted to the child node to the child node, wherein the one or more packets contain at least one of the following: the first Backhaul Adaptation Protocol (BAP) address of the source IAB node, the second BAP address of the access node, or a flag in the BAP subheader.

2. The method according to claim 1, wherein, The UL delivery status information is transmitted via a BAP sublayer control PDU, a BAP sublayer data PDU, or an RLC sublayer control PDU.

3. The method according to claim 1, wherein, The UL delivery status information includes at least one of the following: RLC SN, RLC channel ID or logical channel LCID, backhaul BHRLC channel ID or BAP sublayer SN.

4. The method according to claim 1, wherein, The return RLC channel used to send the one or more packets is configured by the donor CU.

5. The method according to claim 1, wherein, The sub-node is the User Equipment (UE).

6. The method according to claim 1, wherein, The child node is another IAB node.

7. A wireless communication device comprising a processor configured to implement the method of any one of claims 1 to 6.

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