Method and apparatus for enhancing mobility robustness of integrated access and backhaul for new wireless

Abstract

The present disclosure describes methods, systems, and devices for enhancing the mobility robustness of the Integrated Access and Backhaul (IAB) of New Radio (NR). One method includes, during the migration of the NR's migrating integrated access and backhaul node (IAB node) from the source IAB host central unit (CU) to the target IAB host CU, enhancing the mobility robustness of the migrating IAB node by sending a handover request message from the source IAB host CU to the target IAB host CU, the handover request message including Dual Active Protocol Stack (DAPS) request information. Another method includes, during the migration of the NR's migrating IAB node from the source parent IAB node to the target parent IAB node, enhancing the mobility robustness of the migrating IAB node by sending an F1AP message from the IAB host CU to the migrating IAB node, the F1AP message including a Radio Resource Control Re‑configuration (RRCReconfiguration) message, the radio resource control reconfiguration message including DAPS configuration information.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications and more particularly to methods, systems and devices for enhancing mobility robustness of Integrated Access and Backhaul (IAB) for New Radio (NR). Background Art

[0002] Wireless communication technology is pushing the world towards an increasingly connected networked society. Compared with Long Term Evolution (LTE), the Fifth Generation (5G) New Radio (NR) technology has a wider spectrum, such as the millimeter wave (mmWave) frequency band. With the development of massive multiple input multiple output (MIMO) and / or multi-beam systems, 5G NR can provide faster speeds and shorter latency.

[0003] 5G NR may include an Integrated Access Backhaul (IAB) implementation. An IAB implementation may include one or more IAB hosts and multiple connected IAB nodes. Currently, there are issues and / or controversies associated with improving the mobility robustness of migrating IAB nodes.

[0004] The present disclosure may address at least some of the problems / issues associated with existing systems to improve the performance of wireless communications. Summary of the invention

[0005] This document relates to methods, systems, and devices for wireless communications, and more specifically, for enhancing mobility robustness of Integrated Access and Backhaul (IAB) for New Radio (NR).

[0006] In one embodiment, the present disclosure describes a method for wireless communication. The method includes enhancing the mobility robustness of a migrating integrated access and backhaul node (IAB node) of a New Radio (NR) by sending a handover request message from the source IAB host CU to the target IAB host CU during migration from a source IAB host central unit (CU) to a target IAB host CU, the handover request message including a dual active protocol stack (DAPS) request information.

[0007] In another embodiment, the present disclosure describes a method for wireless communication. The method includes, during migration from a source parent IAB node to a target parent IAB node, enhancing the mobility robustness of a migration access and backhaul node (IAB node) of a new radio (NR) by sending an F1AP message to a migration IAB node by a Central Unit (CU) of an IAB host (IAB host CU), the F1AP message including a Radio Resource Control Re-configuration (RRCReconfiguration) message, the RRC reconfiguration message including a Dual Active Protocol Stack (DAPS) configuration information.

[0008] In some other embodiments, a device for wireless communication is described, which may include a memory storing instructions and a processing circuit in communication with the memory. When the processing circuit executes the instructions, the processing circuit is configured to perform the above method.

[0009] In some other embodiments, a device for wireless communication is described, which may include a memory storing instructions and a processing circuit in communication with the memory. When the processing circuit executes the instructions, the processing circuit is configured to perform the above method.

[0010] In some other embodiments, a computer-readable medium is described, comprising instructions that, when executed by a computer, cause the computer to perform the above method.

[0011] The above and other aspects and embodiments thereof are described in more detail in the drawings, detailed description and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1A An example of a wireless communication system including an Integrated Access Backhaul (IAB) system is shown.

[0013] Figure 1B Another example of the architecture of an IAB system is shown.

[0014] Figure 2 An example of an IAB host or an IAB node is shown.

[0015] Figure 3 An example of a user device is shown.

[0016] Figure 4 A flow chart of a method for wireless communication is shown.

[0017] Figure 5 A flow chart of a method for wireless communication is shown.

[0018] Figure 6 A schematic diagram of a migrating IAB node in a central unit (CU) is shown.

[0019] Fig. 7A An exemplary logic flow of a method for wireless communications is shown.

[0020] Figure 7B An exemplary logic flow of a method for wireless communications is shown.

[0021] Figure 8 A schematic diagram showing a migrating IAB node in a centralized inter-unit migration.

[0022] Fig. 9A An exemplary logic flow of a method for wireless communications is shown.

[0023] Fig. 9B An exemplary logic flow of a method for wireless communications is shown. DETAILED DESCRIPTION

[0024] The present disclosure will now be described in detail below with reference to the accompanying drawings, which form a part of the present disclosure and show specific examples of embodiments by way of illustration. However, it is noted that the present disclosure can be embodied in a variety of different forms, and therefore, the subject matter covered or claimed is intended to be construed as not limited to any embodiment set forth below.

[0025] Throughout the specification and claims, terms may have nuanced meanings that are suggested or implied in contexts beyond the explicitly stated meanings. Likewise, the phrases "in one embodiment" or "in some embodiments" as used herein do not necessarily refer to the same embodiment, and the phrases "in another embodiment" or "in other embodiments" as used herein do not necessarily refer to different embodiments. The phrases "in one embodiment" or "in some embodiments" as used herein do not necessarily refer to the same embodiment, and the phrases "in another embodiment" or "in other embodiments" as used herein do not necessarily refer to different embodiments. For example, it is contemplated that the claimed subject matter includes all or part of an exemplary embodiment or combination of embodiments.

[0026] In general, terms can be understood at least in part based on usage in context. For example, terms such as "and", "or" or "and / or" as used herein can include various meanings that can depend at least in part on the context in which such terms are used. Typically, "or" is intended to represent A, B and C (used in an inclusive sense here) and A, B or C (used in an exclusive sense here) when used for an association list (such as A, B or C). In addition, the terms "one or more" or "at least one" as used herein, which depend at least in part on the context, can be used to describe any feature, structure or characteristic in a singular sense, or can be used to describe a combination of features, structures or characteristics in a plural sense. Similarly, terms such as "a / an" or "the" can again be understood to express singular usage or to express plural usage, depending at least in part on the context. In addition, the terms "based on" or "determined by..." can be understood to not necessarily intend to express a unique set of factors, but can again allow the presence of additional factors that are not necessarily explicitly described, depending at least in part on the context.

[0027] The present disclosure describes methods and apparatus for enhancing mobility robustness of Integrated Access and Backhaul (IAB) for New Radio (NR).

[0028] Next Generation (NG) or 5th Generation (5G) wireless communications can provide a range of functions from fast downloads to supporting real-time low-latency communications. Compared with Long Term Evolution (LTE), 5G New Radio (NR) technology has a wider spectrum, including, for example, millimeter wave (mmWave) frequency bands. With the development of large-scale multiple input multiple output (MIMO) and / or multi-beam systems, 5G NR can provide faster speeds and shorter delays. 5G NR may include the development of integrated access backhaul (IAB) implementation methods. IAB implementation methods may include one or more IAB hosts and multiple connected IAB nodes. IAB implementation methods may communicate between one or more IAB hosts and one or more IAB nodes via wireless backhaul and relay links. IAB implementation methods may provide flexible NR cell configurations and increase cell density without increasing the density of IAB hosts.

[0029] The IAB system may include one or more IAB hosts and one or more IAB nodes, which together provide wireless connection services to one or more user equipment (UE) (e.g., smart phones). The IAB host and the IAB node may be a wireless network base station including an NG-Radio Access Network (NG-RAN) base station, which may include a Node B (NB, e.g., gNB) in a mobile communication context. The IAB host may provide access backhaul to one or more connection sub-IAB nodes, and may be connected to the core network via wired communication. In one embodiment, the core network may include a 5G Core Network (5GC). In another embodiment, the wired communication may include optical fiber transmission communication. The IAB node may include a wireless access link and a wireless backhaul link. The wireless access link may be used for communication between the UE and the IAB node. The wireless backhaul link may be used for communication between the IAB node and the IAB host, and / or communication between one IAB node and another IAB node. Therefore, the IAB node does not require a wired communication network for data backhaul. In some embodiments, the IAB node does not include a wired communication network for data backhaul, making the IAB node more flexible and easier to implement, thereby alleviating the burden of implementing a wired communication network. The access link and the backhaul link may use the same frequency transmission band (referred to as in-band relay) or may use different frequency transmission bands (referred to as out-of-band relay).

[0030] refer to Figure 1A and Figure 1B , the IAB host 130 may provide access backhaul 140 to one or more connected child IAB nodes (152 and 154). The IAB host 130 may be connected to the core network 110 via wired communication 120. In one embodiment, the core network 110 may include a 5G core network (5G Core Network, 5GC). In another embodiment, the wired communication 120 may include optical fiber transmission communication. In another embodiment, between two connected IAB nodes (e.g., 154 and 156), the IAB node 154 may be referred to as a parent IAB node, and / or the IAB node 156 may be referred to as a child IAB node.

[0031] The IAB host can provide a wireless connection to one or more user equipment (UE). The UE can be a mobile device, such as a smart phone or a mobile communication module set in a vehicle. For example, the IAB host 130 can provide a wireless connection 160 to the UE 172.

[0032] Similarly, but not limiting, a child or parent IAB node may provide wireless connectivity to one or more UEs. For example, IAB node 152 may provide wireless connectivity 160 to UE 174.

[0033] Similarly, but not limiting, a child IAB node may provide access backhaul to one or more connected grandchild IAB nodes. For example, IAB node 154 may provide access backhaul 140 to IAB node 156. Similarly, but not limiting, a grandchild IAB node may also provide access backhaul to one or more connected great-grandchild IAB nodes and / or provide wireless connectivity to one or more UEs. In another embodiment, IAB node 154 may be a parent IAB node of IAB node 156.

[0034] refer to Figure 1B , the IAB system 100 may include more than one IAB host (130 and 135). Each of the IAB hosts may be connected to the core network (e.g., 5GC) 110 via wired communication 120. In one embodiment, the IAB host 135 may provide access backhaul 140 to one or more connection child IAB nodes 158; and the IAB node 158 may provide wireless connection 160 to one or more UEs 176.

[0035] In another embodiment, the IAB host 130 may include at least one centralized unit (CU) (e.g., an IAB host CU 131) and at least one distributed unit (DU) (e.g., an IAB host-DU 132). At least one IAB host DU 132 may be connected to at least one IAB host CU 131, and then at least one IAB host CU 131 may be connected to the 5GC 110.

[0036] Similarly, in another embodiment, the IAB host 135 may include at least one CU (e.g., IAB host CU 136) and at least one DU (e.g., IAB host-DU 137). At least one IAB host DU 137 may be connected to at least one IAB host CU 136, and then at least one IAB host CU 136 may be connected to the 5GC 110.

[0037] IAB node 156 currently connected to IAB host 130 via IAB node 154 may migrate to IAB host 135. This may be referred to as an inter-host migration and IAB node 156 may be referred to as a migrating IAB node. Currently, there are issues and / or problems associated with configuring migrating IAB nodes during inter-host migration.

[0038] The present disclosure describes embodiments of methods and devices for enhancing the mobility robustness of IAB of NR. In order to improve the efficiency of wireless communications, the topology and flexibility of the architecture are greatly improved. Specifically, the existing and / or improved architecture can support inter-CU migration of IAB nodes and multipath transmission of IAB nodes. This complex and flexible architecture can bring advantages to IAB network performance and may place higher requirements on network control. The present disclosure can solve one or more problems associated with IAB migration, such as how to ensure seamless transmission during IAB migration.

[0039] The present disclosure describes a method for maintaining transmission using the principle of Dual Active Protocol Stack (DAPS) during IAB migration. The principle of DAPS-Handover (DAPS-HO) can allow the migrating IAB node to maintain a connection with the source parent IAB node cell to remain active in order to transmit user data until the migrating IAB node is able to transmit user data with the target parent IAB node. During the IAB migration process, the migrating IAB node can receive DL data simultaneously with the source parent IAB node and the target parent IAB node in a short period of time.

[0040] Figure 2 An exemplary wireless communication base station 200 is shown. The wireless communication base station 200 may be Figure 1A and Figure 1B 130 and 135 and / or an exemplary embodiment of at least one of the IAB hosts (130 and 135) and / or IAB nodes (152, 154, 156, and 158) in the base station 200. The base station 200 may include a wireless transmit / receive (Tx / Rx) circuit 208 to transmit / receive communications with one or more UEs and / or one or more other base stations. The base station may also include a network interface circuit 209 to communicate the base station with other base stations and / or a core network (e.g., via optical or wired interconnection, Ethernet, and / or other data transmission media / protocols). The base station 200 may optionally include an input / output (I / O) interface 206 to communicate with an operator or the like.

[0041] The base station may also include system circuitry 204. System circuitry 204 may include one or more processors 221 and / or memory 222. Memory 222 may include an operating system 224, instructions 226, and parameters 228. Instructions 226 may be configured to cause one or more of processors 124 to perform functions of the base station. Parameters 228 may include parameters for supporting the execution of instructions 226. For example, the parameters may include network protocol settings, bandwidth parameters, radio frequency mapping allocations, and / or other parameters.

[0042] Figure 3An exemplary user equipment (UE) 300 is shown. UE 300 may be a mobile device, such as a smart phone or a mobile communication module provided in a vehicle. UE 300 may be Figure 1A and Figure 1B 300. UE 300 may include a communication interface 302, a system circuit 304, an input / output (I / O) interface 306, a display circuit 308, and a storage device 309. The display circuit may include a user interface 310. The system circuit 304 may include any combination of hardware, software, firmware, or other logic / circuits. The system circuit 304 may be implemented, for example, with one or more systems on chip (Systems On Chip, SoC), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), discrete analog and digital circuits, and other circuits. The system circuit 304 may be part of an implementation of any desired functionality in the UE 300. In this regard, the system circuit 304 may include logic that facilitates, for example, the following: decoding and playing music and video, such as MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV decoding and playback; running applications; accepting user input; saving and retrieving application data; establishing, maintaining, and terminating mobile phone calls or data connections, such as Internet connections; establishing, maintaining, and terminating wireless network connections, Bluetooth connections, or other connections; and displaying relevant information on the user interface 310. The user interface 310 and the input / output (I / O) interface 306 may include a graphical user interface, a touch-sensitive display, tactile feedback or other tactile output, voice or facial recognition input, buttons, switches, speakers, and other user interface elements. Additional examples of the I / O interface 306 may include microphones, video and still image cameras, temperature sensors, vibration sensors, rotation and orientation sensors, headphone and microphone input / output jacks, Universal Serial Bus (USB) connectors, memory card slots, radiation sensors (e.g., IR sensors), and other types of inputs.

[0043] refer to Figure 3, the communication interface 302 may include radio frequency (RF) transmission (Tx) and reception (Rx) circuits 316 that transmit and receive signals through one or more antennas 314. The communication interface 302 may include one or more transceivers. The transceiver may be a wireless transceiver that includes modulation / demodulation circuits, digital to analog converters (DAC), shaping tables, analog to digital converters (ADC), filters, waveform shapers, filters, preamplifiers, power amplifiers, and / or other logic for transmitting and receiving through one or more antennas or (for some devices) through a physical (e.g., wired) medium. The transmitted and received signals may follow any of a variety of formats, protocols, modulations (e.g., QPSK, 16-QAM, 64-QAM, or 256-QAM), channels, bit rates, and encodings. As a specific example, the communication interface 302 may include a transceiver that supports transmission and reception according to 2G, 3G, BT, Wi-Fi, Universal Mobile Telecommunications System (UMTS), High Speed ​​Packet Access (HSPA) +, 4G / Long Term Evolution (LTE), and 5G standards. However, whether from the 3rd Generation Partnership Project (3GPP), GSM Association, 3GPP2, IEEE, or other partners or standards bodies, the techniques described below are applicable to other wireless communication technologies.

[0044] refer to Figure 3 , the system circuit 304 may include one or more processors 321 and a memory 322. The memory 322 stores, for example, an operating system 324, instructions 326, and parameters 328. The processor 321 is configured to execute the instructions 326 to perform the desired functions of the UE 300. The parameters 328 may provide and specify configuration and operating options for the instructions 326. The memory 322 may also store any BT, Wi-Fi, 3G, 4G, 5G, or other data that the UE 300 will send through the communication interface 302 or has received through the communication interface 302. In various embodiments, the system power of the UE 300 may be provided by a power storage device such as a battery or a transformer.

[0045] The present disclosure describes several embodiments of methods and devices for enhancing mobility robustness of a migrating integrated access and backhaul node (IAB node) for New Radio (NR), which may be partially or fully described in the above Figure 2 and Figure 3 The method is implemented on one or more wireless network base stations and / or one or more user devices described in the method.

[0046] refer to Figure 4 , the present disclosure describes an embodiment of a method 400 for enhancing the mobility robustness of a migrating IAB node for NR during migration from a source IAB host central unit (CU) to a target IAB host CU. The method 400 may include step 410: sending a handover request message by the source IAB host CU to the target IAB host CU, the handover request message including a dual active protocol stack (DAPS) request information. In one embodiment, the DAPS request information is included in a HANDOVER REQUEST handover request message for a given backhaul (BH) radio link control (RLC) channel of the migrating IAB node. In another embodiment, the DAPS request information indicates that the source IAB host CU requests a DAPS handover (HO) for a related BH RLC channel.

[0047] The method 400 may optionally include, when the target IAB host CU receives the handover request message, the target IAB host CU responding to the source IAB host CU by sending a handover request confirmation message to the source IAB host CU, the handover request confirmation message including DAPS response information. Optionally, in one embodiment, the DAPS response information indicates a response to a DAPS handover (HO) request for a given backhaul (BH) radio link control (RLC) channel of the migrated IAB node.

[0048] refer to Figure 5, the present disclosure describes an embodiment of a method 500 for enhancing the mobility robustness of a migrating Integrated Access and Backhaul (IAB) node of a New Radio (NR) during migration from a source access and backhaul (IAB) node to a target parent IAB node. The method 500 may include step 510: a Central Unit (CU) of an IAB host (IAB host CU) sends an F1AP message to the migrating IAB node, the F1AP message including a Radio Resource Control Re-configuration (RRCReconfiguration) message, the RRC reconfiguration message including a Dual Active Protocol Stack (DAPS) configuration information. In one embodiment, the DAPS configuration information is included for a given backhaul (BH) radio link control (RLC) channel of the migrating IAB node.

[0049] Optionally, in one embodiment, the method 500 may include the IAB host CU sending an F1AP message to the migration IAB node to instruct the source parent IAB node to continue to send downlink (DL) data to the migration IAB node during the migration.

[0050] Optionally, in another embodiment, the method 500 may include the IAB host CU sending an F1AP message to the access IAB node to instruct the access user equipment (UE) to perform uplink data switching through a downlink medium access control control element (DL MAC CE). In one embodiment, the access IAB node may be at least one of a migration IAB node and / or a descendant IAB node of the migration IAB node.

[0051] Optionally, in another embodiment, the method 500 may include the migrating IAB node modifying a Backhaul Adaptation Protocol (BAP) header of uplink forwarding data during migration.

[0052] In various embodiments, reference Figure 6 , the IAB system 600 may include an IAB host 610. The IAB host 610 may include a centralized unit (IAB host CU) and one or more distributed units (IAB host DU). For example but not limited to, Figure 6 In the embodiment, the IAB host 610 may include an IAB host CU 612 , a source IAB host DU 613 , and a target IAB host DU 614 .

[0053] Currently via the source path including the source IAB host DU 613 ( Figure 6 The IAB node 650 connected to the IAB host CU 612 by the dashed line in the figure may be migrated to be connected to the IAB host CU 612 via a target path including the target IAB host DU 614. The IAB node 650 may be referred to as a migration IAB node. In one embodiment, considering that the migration occurs within an IAB host CU, Figure 6 The migration in can be optionally referred to as intra-CU migration.

[0054] The source path may further include one or more intermediate hop IAB nodes 622 on the source path, and / or a source parent IAB node 630. The source parent IAB node may include a mobile terminal (MT) 632 and a DU 634.

[0055] The target path may further include one or more intermediate hop IAB nodes 624 on the target path, and / or a target parent IAB node 640. The target parent IAB node may include a mobile terminal (MT) 642 and a DU 644.

[0056] The migration IAB node 650 may include an MT 652 and a DU 654. In one embodiment, the migration IAB node 650 may be connected to one or more user equipments (UE), such as UE 670. In another embodiment, the migration IAB node 650 may be connected to one or more descendant IAB nodes (UE) or child IAB nodes, such as descendant IAB node 660.

[0057] Before migration, the migration IAB node 650 may communicate with the source parent IAB node 630. Figure 6 , the migration IAB node 650 may change its attachment point from the source parent IAB node 630 connected to the source IAB host DU 613 to the target parent IAB node 640 connected to the target IAB host DU 614. In one embodiment, a handover (HO) process may occur during the migration, and this may be an intra-CU HO scenario. The migration IAB node DU 454 may communicate with the IAB host CU 612 via F1-AP messages.

[0058] The present disclosure describes various embodiments of a method for maintaining transmission during intra-CU IAB migration using the principles of a Dual Active Protocol Stack (DAPS).

[0059] Fig. 7A and Figure 7B The logic flow of a method 700 for enhancing the mobility robustness of a migration IAB node 650 during migration from a source parent IAB node 630 to a target parent IAB node 640 is shown. A UE 670 may be connected to the migration IAB node 650 and migrate together with the migration IAB node 650. Before migration, the migration IAB node 650 may be connected to an IAB host CU 612 via a source path including the source parent IAB node 630, one or more intermediate hop IAB nodes 622, and a source IAB host DU 613. After migration, the migration IAB node 650 may be connected to an IAB host CU 612 via a target path including the target parent IAB node 640, one or more intermediate hop IAB nodes 624, and a target IAB host DU 614.

[0060] In various implementations, method 700 may optionally include: Fig. 7A and Figure 7B Some or all of the steps in the present invention may be performed, and the embodiments described in the present disclosure are examples of various implementations rather than limitations on the various implementations.

[0061] refer to Fig. 7A In step 712, the migration IAB node 650 may send a MeasurementReport message to the source parent IAB node 630. In one embodiment, the MT of the migration IAB node may send a MeasurementReport message to the DU of the source parent IAB node. In another embodiment, the MeasurementReport message may be based on the measurement configuration previously received by the migration IAB node MT from the IAB host CU 612.

[0062] refer to Fig. 7A In step 714, the source parent IAB node 630 may send a UL RRC MESSAGE TRANSFER message to the IAB host CU 612. In one embodiment, the DU of the source parent IAB node may send a UL RRC MESSAGE TRANSFER message to the IAB host CU 612. In another embodiment, the UL RRC MESSAGE TRANSFER message may convey the received MeasurementReport to the IAB host CU.

[0063] refer to Fig. 7AIn step 716 of the embodiment, the IAB host CU 612 may send a UE CONTEXT SETUP REQUEST message to the target parent IAB node 640. In one embodiment, the IAB host CU 612 may send a UE CONTEXT SETUP REQUEST message to the DU of the target parent node IAB. In another embodiment, the UE CONTEXT SETUP REQUEST message is configured to create a UE context for the migration IAB-MT and set up one or more bearers. In another embodiment, these bearers may be used by the migration IAB-MT for its own signaling, and optionally for data traffic.

[0064] refer to Fig. 7A In step 718, upon receiving the UE CONTEXT SETUP REQUEST message, the DU of the target parent IAB node 640 may respond to the IAB host CU 612 via a UE CONTEXT SETUP RESPONSE message.

[0065] refer to Fig. 7A In step 720, the IAB host CU 612 may send a UECONTEXT MODIFICATION REQUEST message to the DU of the source parent IAB node 630. In one embodiment, the UE CONTEXT MODIFICATION REQUEST message may include the generated RRCReconfiguration message. The RRCReconfiguration message may include a default BH RLC channel and a default BAP routing ID configuration for UL F1-C traffic mapping on the target path. In another embodiment, the RRCReconfiguration message may include an additional BH RLC channel.

[0066] Optionally, step 720 may include allocating one or more Transport Network Layer (TNL) addresses that can be routed via the target IAB host DU. The new one or more TNL addresses may be included in the RRCReconfiguration message as a replacement for the one or more TNL addresses that can be routed via the source IAB host DU. In one embodiment, when IPsec tunnel mode is used to protect F1 and non-F1 traffic, the allocated TNL address is an external IP address. If the source path and the target path use the same IAB host DU, no TNL address replacement is required.

[0067] Optionally, the RRCReconfiguration message may include a DAPS configuration of one or more BH RLC channels between the MT of the migrating IAB node 650 and the DU of the target parent IAB node 640, and a DAPS configuration of one or more dedicated radio bearers (DRBs) for one or more UEs 670 connected to the migrating IAB node 650.

[0068] Optionally, the UE CONTEXT MODIFICATION REQUEST message may include a transmission action indicator, which indicates not to stop data transmission to the migration IAB node.

[0069] refer to Fig. 7A In step 722 , the DU of the source parent IAB node 630 may forward the received RRCReconfiguration message to the MT of the migration IAB node 650 .

[0070] refer to Fig. 7A In step 724, the DU of the source parent IAB node 630 may respond to the IAB host CU 612 via a UE CONTEXT MODIFICATION RESPONSE message.

[0071] refer to Fig. 7A In step 726 of , a random access procedure for the migrated IAB node 650 may be performed at the DU of the target parent IAB node 640 .

[0072] refer to Fig. 7A In step 728, the MT of the migrating IAB node 650 may respond to the DU of the target parent IAB node 640 via an RRCReconfigurationComplete message.

[0073] refer to Fig. 7A In step 730 of the target parent IAB node 640, the DU may send a UL RRCMESSAGE TRANSFER message to the IAB host CU 612 to convey the received RRCReconfigurationComplete message.

[0074] Optionally, step 730 may include that an uplink (UL) packet may be sent from the MT of the migrating IAB node 650 and forwarded to the IAB host CU 612 via the DU of the target parent IAB node 640. In one embodiment, the UL packet may belong to signaling of the MT of the migrating IAB node 650 and optionally to data traffic.

[0075] refer to Figure 7B In step 732 of step 716, the IAB host CU may configure one or more BH RLC channels and one or more BAP sublayer routing entries on the target path between the target parent IAB node 640 and the target IAB host DU 614, and configure one or more downlink (DL) mappings for the target path of the migrated IAB node on the target IAB host DU 614. In one embodiment, optionally, the above configuration may be performed at an earlier stage, for example, immediately after step 716. In another embodiment, the IAB host CU 612 may establish one or more additional BH RLC channels to the MT of the migrated IAB node 650 via an RRC message.

[0076] refer to Figure 7B In step 734, the F1-C connection may be switched to use one or more new TNL addresses of the migrated IAB node. The IAB host CU 612 may update the BH information associated with each GTP tunnel to the migrated IAB node 650. Optionally, step 734 may also update the UL FTEID and DL FTEID associated with each GTP tunnel. In one embodiment, all F1-U tunnels may be switched to use one or more new TNL addresses of the migrated IAB node. In another embodiment, this step may use non-UE associated signaling in the E1 and / or F1 interfaces to provide updated UP configurations for the F1-U tunnels of one or more connected UEs, or child IAB nodes, or descendant IAB nodes.

[0077] Optionally, in step 734, the IAB host CU 612 may update the UL BH information associated with the non-UP traffic. Optionally, in another embodiment, an uplink retransmission packet for one or more DAPS-configured DRBs and / or BH RLC channels may be sent from the MT of the migration IAB node 650, and the uplink retransmission packet may be forwarded to the IAB host CU 612 via the DU 640 of the target parent IAB node. Optionally, in another embodiment, the migration IAB node 650 may modify the BAP header of the uplink retransmission packet.

[0078] refer to Figure 7B In step 736 , the IAB host CU 612 may send a UECONTEXT RELEASE COMMAND message to the DU of the source parent IAB node 630 .

[0079] refer to Figure 7BIn step 738 of the source parent IAB node 630, the DU may release the context of the MT of the migration IAB node 650 and respond to the IAB host CU 612 with a UE CONTEXT RELEASE COMPLETE message.

[0080] refer to Figure 7B In step 740 , the IAB host CU 612 may release the one or more BH RLC channels and the one or more BAP sublayer routing entries on the source path between the source parent IAB node 630 and the source IAB host DU 613 .

[0081] In various embodiments, reference Figure 8 , the IAB system 800 may include a source IAB host CU 811 and a target IAB host CU 812. Currently, the source path ( Figure 8 The migration IAB node 650 connected to the source IAB host CU 811 by the dashed line in FIG. 6A may be migrated so as to be connected to the target IAB host CU 812 via a target path including the target IAB host DU 614. In one embodiment, considering that the migration occurs between more than one IAB host CU, Figure 8 The migration in may alternatively be referred to as inter-CU migration, for example, migration from the source IAB host CU 811 to the target IAB host CU 812.

[0082] Before migration, the migration IAB node 650 may communicate with the source parent IAB node 630. Figure 8 , the migration IAB node 650 may change its attachment point from the source parent IAB node 630 connected to the source IAB host CU 811 to the target parent IAB node 640 connected to the target IAB host CU 812. In one embodiment, a handover (HO) process may occur during the migration, and this may be an inter-CU HO scenario. The migration IAB node DU454 may communicate with the source IAB host CU 811 and / or the target IAB host CU 812 via F1-AP messages.

[0083] The present disclosure describes various embodiments of a method for maintaining transmission during inter-CU IAB migration using the principles of a Dual Active Protocol Stack (DAPS).

[0084] Fig. 9A and Fig. 9BThe logic flow of a method 900 for enhancing the mobility robustness of a migration IAB node 650 during migration from a source IAB host CU 811 to a target host CU 812 is shown. The UE 670, and / or any child IAB node / descendant IAB node may be connected to the migration IAB node 650 and migrated together with the migration IAB node 650. Before migration, the migration IAB node 650 may be connected to the source IAB host CU 811 via a source path including a source parent IAB node 630 and a source IAB host DU 613. After migration, the migration IAB node 650 may be connected to the target IAB host CU 812 via a target path including a target parent IAB node 640 and a target IAB host DU 614.

[0085] In various implementations, method 900 may optionally include: Fig. 9A and Fig. 9B Some or all of the steps in the present invention may be performed, and the embodiments described in the present disclosure are examples of various implementations rather than limitations on the various implementations.

[0086] refer to Fig. 9A In step 912, the MT of the migrated IAB node 650 may send a MeasurementReport message to the DU of the source parent IAB node 630. In one embodiment, the MeasurementReport message may be based on the measurement configuration previously received by the migrated IAB node from the source IAB host CU 811.

[0087] refer to Fig. 9A In step 914 of the example, the DU of the source parent IAB node 630 may send a UL RRCMESSAGE TRANSFER message to the source IAB host CU 811 to convey the received MeasurementReport message.

[0088] refer to Fig. 9A In step 916 of , the source IAB host CU 811 may send a HANDOVER REQUEST message with information required for preparing the handover at the target side to the target IAB host CU 812. Optionally, in one embodiment, the HANDOVER REQUEST message may indicate a DAPS HO request for the associated DRB or the associated BH RLC channel.

[0089] refer to Fig. 9AIn step 918 of the embodiment, the target IAB host CU 812 may perform admission control and respond to the source IAB host CU 811 with a HANDOVERREQUEST ACKNOWLEDGE message. Optionally, in one embodiment, the HANDOVERREQUEST ACKNOWLEDGE message may include information required for accessing the target side. Optionally, in another embodiment, the HANDOVERREQUEST ACKNOWLEDGE message may indicate a DAPSHO response for the relevant DRB or the relevant BH RLC channel.

[0090] refer to Fig. 9A In step 920, the source IAB host CU 811 may send a UECONTEXT MODIFICATION REQUEST message to the DU of the source parent IAB node 630. In one embodiment, the UECONTEXT MODIFICATION REQUEST message may include the generated RRCReconfiguration message.

[0091] Optionally, in another embodiment, the RRCReconfiguration message may include a default BH RLC channel and a default backhaul adaptation protocol (BAP) routing identification (ID) configuration for UL F1-C traffic mapping on the target path. Optionally, in another embodiment, the RRCReconfiguration message may include one or more additional BH RLC channels.

[0092] Alternatively, in another embodiment, step 920 may include allocating one or more TNL addresses routable via the target IAB host DU 614. Alternatively, in another embodiment, the RRCReconfiguration message may include one or more new TNL addresses as a replacement for the one or more TNL addresses routable via the source IAB host DU.

[0093] Optionally, in another embodiment, where IPsec tunnel mode is used to protect F1 and non-F1 traffic, the assigned TNL address is an external IP address. If the source path and the target path use the same IAB host DU, no TNL address replacement is required.

[0094] Optionally, in another embodiment, the RRCReconfiguration message may include a DAPS-HO indication for related BH RLC channels between the MT and the migrating IAB node and the target parent IAB-DU, and a DAPS-HO indication for related DRBs of the UE connected to the migrating IAB node.

[0095] Optionally, in another embodiment, the UE CONTEXT MODIFICATION REQUEST message may include a transmission action indicator, which indicates not to stop data transmission to the migration IAB node.

[0096] refer to Fig. 9A In step 922 , the DU of the source parent IAB node 630 may forward the received RRCReconfiguration message to the MT of the migration IAB node 650 .

[0097] refer to Fig. 9A In step 924, the DU of the source parent IAB node 630 may respond to the source IAB host CU 811 via a UE CONTEXT MODIFICATION RESPONSE message.

[0098] refer to Fig. 9A In step 926 , a random access procedure may be performed at the DU of the target parent IAB node 640 .

[0099] refer to Fig. 9A In step 928, the MT of the migrated IAB node 650 may respond to the DU of the target parent IAB node 640 via an RRCReconfigurationComplete message.

[0100] refer to Fig. 9A In step 930, the DU of the target parent IAB node may send a UL RRCMESSAGE TRANSFER message to the source IAB host CU 812 to convey the received RRCReconfigurationComplete message. Optionally, in another embodiment, an uplink data packet may be sent from the migration IAB-MT, which is forwarded to the target IAB host CU 812 by the DU of the target parent IAB node 640. Optionally, in another embodiment, the UL data packet belongs to the IAB-MT's own signaling and optionally belongs to data traffic.

[0101] refer to Fig. 9BIn step 932, the target IAB host CU 812 may send a UECONTEXT SETUP REQUEST message to the DU of the target parent IAB node 640 to create a UE context for the migration IAB node and set up one or more bearers. In one embodiment, the one or more bearers may be used by the migration IAB node 650 for its own signaling and, optionally, for data traffic.

[0102] refer to Fig. 9B In step 934, the DU of the target parent IAB node 640 may respond to the target IAB host CU 812 via a UE CONTEXT SETUP RESPONSE message.

[0103] refer to Fig. 9B In step 936 of step 916, the target IAB host CU 812 may configure one or more BH RLC channels and one or more BAP sublayer routing entries on the target path between the target parent IAB node 640 and the target IAB host DU 614, and configure DL mapping for the target path of the migrating IAB node on the target IAB host DU 614. Optionally, in one embodiment, the configuration may be performed at an earlier stage, for example, immediately after step 916. Optionally, in another embodiment, the target IAB host CU 812 may establish one or more additional BH RLC channels to the migrating IAB node via an RRC message.

[0104] refer to Fig. 9B In step 938 of the embodiment, the F1-C connection may be switched to use one or more new TNL addresses of the migrated IAB node. Optionally, in one embodiment, the target IAB host CU 812 may update the BH information associated with each GTP tunnel to the migrated IAB node 650.

[0105] Optionally, in another embodiment, step 938 may also include updating the UL FTEID and DL FTEID associated with each GTP tunnel. Optionally, in another embodiment, all F1-U tunnels may be switched to use one or more new TNL addresses of the migrated IAB node. Optionally, in another embodiment, step 938 may include using non-UE associated signaling in the E1 and / or F1 interface to provide updated UP configurations for multiple F1-U tunnels connected to UEs or sub-IAB-MTs.

[0106] Optionally, in another embodiment, the target IAB host CU 812 may update the UL BH information associated with non-UP traffic. Optionally, in another embodiment, the IAB host CU sends an F1AP message to the access IAB node to instruct its access UE to perform uplink data switching through DL MAC CE. After receiving the DL MAC CE, the UE performs an uplink data switching process. Uplink retransmission packets for one or more DAPS-HO DRBs and / or one or more BH RLC channels may be sent from the MT of the migration IAB node 650, and the uplink retransmission packets are forwarded to the target IAB host CU 812 through the DU 640 of the target parent IAB node.

[0107] Optionally, in another embodiment, the migration IAB node 650 may modify the BAP header of the uplink retransmission data packet.

[0108] refer to Fig. 9B In step 940 , the target IAB host CU 812 may send a switching success message to the source IAB host CU 811 .

[0109] refer to Fig. 9B In step 942 , the source IAB host CU 811 may send a UECONTEXT RELEASE COMMAND message to the DU of the source parent IAB node 630 .

[0110] refer to Fig. 9B In step 944 , the DU of the source parent IAB node 630 may release the context of the migrated IAB-MT and respond to the source IAB host CU 811 with a UE CONTEXT RELEASE COMPLETE message.

[0111] refer to Fig. 9B In step 946 of , the source IAB host CU 811 may release the one or more BH RLC channels and the one or more BAP sublayer routing entries on the source path between the source parent IAB node 630 and the source IAB host DU 613 .

[0112] refer to Fig. 9B In step 948 of the embodiment, the target IAB host CU 812 may send an RRCReconfiguration message to the MT of the migrated IAB node 650. In one embodiment, the RRCReconfiguration message may include a DAPS-HO release indication. Alternatively, in another embodiment, the MT of the migrated IAB node 650 may release the connection with the source parent IAB node 630.

[0113] The present disclosure describes methods, apparatus, and computer-readable media for wireless communications. The present disclosure addresses the problem of enhancing the mobility robustness of a migrating integrated access and backhaul-node (IAB-node) of a New Radio (NR) during inter-CU or intra-CU migration. The methods, devices, and computer-readable media described in the present disclosure can facilitate the performance of wireless communications by sending a handover request message including a Dual Active Protocol Stack (DAPS) configuration request, thereby improving migration efficiency and overall wireless network performance. The methods, devices, and computer-readable media described in the present disclosure can improve the overall efficiency of a wireless communication system.

[0114] Reference throughout this specification to features, advantages, or similar language does not imply that all features and advantages that can be achieved with the present solution should be included or included in any single embodiment thereof. Rather, language referring to features and advantages is understood to mean that a particular feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present solution. Thus, discussion of features and advantages and similar language throughout the specification may, but do not necessarily, refer to the same embodiment.

[0115] In addition, the features, advantages, and characteristics described in the present solution may be combined in any suitable manner in one or more embodiments. Based on the description herein, one of ordinary skill in the relevant art will recognize that the present solution may be practiced without one or more of the specific features or advantages of a particular embodiment. In other cases, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the present solution.

Claims

1. A method for wireless communication, comprising: During the migration of a migrating integrated access and backhaul node (IAB node) of New Radio (NR) from a source integrated access and backhaul (IAB) hosting centralized unit (CU) to a target IAB hosting CU, the mobility robustness of the migrating IAB node is enhanced by the following steps: The source IAB host CU sends a switching request message to the target IAB host CU, wherein the switching request message includes dual active protocol stack (DAPS) request information; wherein, The DAPS request information is included in the handover request message for a given backhaul (BH) radio link control (RLC) channel of the migrating IAB node.

2. The method according to claim 1, wherein: The DAPS request information is used to indicate that the source IAB host CU requests a DAPS handover (HO) for a related BH RLC channel.

3. The method according to claim 1, wherein: When the target IAB host CU receives the handover request message, the target IAB host CU responds to the source IAB host CU by sending a handover request confirmation message to the source IAB host CU, and the handover request confirmation message includes DAPS response information.

4. The method according to any one of claims 2 to 3, wherein: The DAPS response information is used to indicate a response to a DAPS handover (HO) requested for a given backhaul (BH) radio link control (RLC) channel of the migrating IAB node.

5. A method for wireless communication, comprising: During the migration of a migrating integrated access and backhaul node (IAB node) of New Radio (NR) from a source parent integrated access and backhaul (IAB) node to a target parent IAB node, the mobility robustness of the migrating IAB node is enhanced by the following steps: A centralized unit (CU) of the IAB host (IAB host CU) sends an F1AP message to the migration IAB node, wherein the F1AP message includes a radio resource control reconfiguration (RRCReconfiguration) message, and the radio resource control reconfiguration message includes DAPS configuration information; in: The DAPS configuration information is included for a given backhaul (BH) radio link control (RLC) channel of the migrating IAB node.

6. The method according to claim 5, wherein: The IAB host CU sends an F1AP message to the migration IAB node to instruct the source parent IAB node to continue to send downlink (DL) data to the migration IAB node during the migration.

7. The method according to claim 5, wherein: The IAB host CU sends an F1AP message to the access IAB node to instruct the access user equipment (UE) to perform uplink data switching through a downlink medium access control control element (DL MAC CE).

8. The method according to claim 7, wherein: The access IAB node includes at least one of the following items: said migrating IAB node, or The descendant IAB node of the migrated IAB node.

9. The method according to claim 5, wherein: The migration IAB node modifies a Backhaul Adaptation Protocol (BAP) header of uplink forwarding data during the migration.

10. A wireless communication device, comprising a processor and a memory, wherein the processor is configured to read a code from the memory and execute the method according to any one of claims 1 to 9.

11. A computer program product comprising computer readable program medium code stored thereon, which, when executed by a processor, causes the processor to perform the method according to any one of claims 1 to 9.

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