System and method for indicating an access beam to a user device (UE) during RACH-less handover for mobile integrated access and backhaul (mIAB).

Abstract

A method (1300) using a UE (User Equipment) (102) for mIAB (Mobile Integrated Access and Backhaul) includes receiving information (1302) indicating a beam to be transmitted from a target DU (Distributed Unit) (104) during the HO of the UE from a first cell to a second cell. The HO includes an mIAB RACH-less (Random Access Channel-less) HO.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, and more specifically, to systems and methods for indicating an access beam to user equipment (UE) during RACH-less handover for mobile integrated access and backhaul (mIAB).

Background Art

[0002] In Release 18, various radio access network (RAN) groups are expected to work on enhancing the functions of integrated access and backhaul (IAB) via mobile IAB (mIAB), thereby providing 5th generation (5G) coverage enhancement for on-board and surrounding user equipment (UE). The initial use case of mobile IAB / vehicle mounted relay (VMR) is expected to be based on 3GPP® TR 22.839 V.18.1.0.

[0003] One of the main use cases of an mIAB cell is to serve UE located in a vehicle equipped with a VMR. Other relevant use cases of mobile IAB include mobile / nomadic IAB network nodes mounted on vehicles to provide extended coverage. This includes scenarios where additional coverage is required during special events such as concerts, or during disasters. While nomadic IAB nodes provide access to surrounding UEs, backhaul traffic from nomadic IAB nodes is transmitted over the air with the help of either an IAB donor or a non-terrestrial network (NTN). Nomadic IAB nodes reduce or even eliminate signal strength loss due to vehicle penetration for UE located inside the vehicle.

[0004] The advantages of mIAB include the reduction / elimination of vehicle transmission loss (especially at high frequencies) and / or the reduction / elimination of group handover.

[0005] In most use cases, the mIAB is expected to be installed in public transport vehicles. For the majority of cases, the mIAB is expected to travel along a predetermined route. Figure 1 shows one such mIAB installed in a bus traveling on a route covered by four different parent IAB nodes, indicated as Parent 1, Parent 2, Parent 3, and Parent 4. The parent nodes backhaul the traffic through two donor nodes, indicated as Donor X and Donor Y.

[0006] An IAB node has IAB-Distributed Units (IAB-DUs) that provide access to the surrounding UEs. An IAB node also has IAB-Mobile Terminations (IAB-MTs) that provide backhaul connectivity from the IAB node to its (one or more) parent nodes and the rest of the network. A parent IAB node consists of IAB-DUs that provide access to the UEs and mIABs present in the coverage area of ​​each IAB-DU. An IAB node also includes an IAB-MT that backhauls its own traffic along with traffic from the mIAB nodes. Finally, the two donor nodes consist of a Distributed Unit (DU) that provides access and a Centralized Unit (CU) that connects to the core network. The CUs of both donor nodes maintain F1 connectivity to the IAB-DUs below them.

[0007] When an mIAB node moves from one geographical area to the next, it passes through different areas covered by various cells of a fixed parent node.

[0008] Figure 2 illustrates UE handover (HO) between cells associated with different logical IAB-DUs connected to separate CUs. Generally, third-generation partnership projects (3GPP) assume that mIAB-DU migration between different donor CUs is achieved by providing a second logical mIAB-DU (IAB-DU2) to the mIAB node, which then establishes an F1 connection with the target donor CU (IAB-donor-CU2) for the mIAB-DU migration. Subsequently, UEs served by the mIAB node are handed over from the mIAB-DU1 cell controlled by the source donor CU (CU1) to the mIAB-DU2 cell controlled by the target donor CU (CU2). Although the two cells reside on the same physical IAB node, they have separate F1 connections to IAB-donor-CU1 and IAB-donor-CU2, respectively, as shown in Figure 2. After the UE is handed over between mIAB-DU1 and mIAB-DU2, the first connection between mIAB-DU1 and IAB-donor-CU1 is released.

[0009] HOs performed without executing the RACH procedure are sometimes called RACH-less HOs. Some of the 3GPP RAN2 agreements regarding RACH-less HOs in the Mobile IAB are as follows: Agreements reached at the RAN2#121bis meeting: ●The feasibility of beam processing during RACH-less HO in mIAB WI is [a matter for future consideration (FFS)] (and this needs to be addressed in order for RACH-less to be supported in mIAB). ●RAN2 further discusses the following options to support beam operation for the initial uplink (UL) transmit / downlink (DL) receive to the target logic DU in random access channelless (RACH-less) HO during DU migration. ●Option 1: (Explicit Approach) Explicit beam information is included in the HO command. See FFS for details. ●Option 2: (Implicit approach) The UE reuses the same beam status as the source cell (beam information is not explicitly included in the HO command). ● A RACH-less HO in the same timing advance (TA) with a security key change is within the scope for serving UEs during mIAB DU migration. The UL grant and HO completion procedure in mIAB RACH-less HO is FFS. Agreements reached at RAN2#122 meeting: ●RAN2 believes that for legacy UEs to perform fast handovers from the UE's perspective, it is important that the target cell is known to the UE (detected and measured). ●In the case of RACH-less configuration, beam indication (within the RRC HO command) will be required if supported, which appears to be achievable in this release from R2's perspective. R2 assumes that the network can know / select beams from network implementation-specific knowledge or from UE measurement reports (legacy reports). ●Regarding UL grant and HO completion in RACH-less HO: 1. Both Type 1 configurable grants and dynamic grants are supported. 2. The monitoring timer process and the time when HO is considered to have completed successfully is FFS (expected to be consistent with other WIs). ●Send an LS to RAN3 to check if there are any problems / feasibility concerns.

[0010] However, at present, there are (one or more) challenges. For example, according to discussions in the 3GPP RAN2 Working Group, RACH-less handover for UEs served by mobile IAB nodes will be supported in Release 18. However, one unresolved issue is how to inform a UE which beam to use when switching to a second logical mIAB-DU. This is also related to the following agreement:

[0011] In the case of RACH-less configuration, beam indication (within the RRC HO command) would be required if supported, which appears to be achievable in this release from R2's perspective. R2 assumes that the network can know / select beams from network implementation-specific knowledge or from UE measurement reports (legacy reports).

[0012] According to previous (i.e., Layer 3 (L3)) HO techniques, it is usually the UE that determines which beam to use in the target cell during the RACH procedure. However, when the RACH procedure is not involved, it is impossible for the UE to determine which beam should be used in the target (second) logical mIAB-DU. [Overview of the project]

[0013] Certain aspects and embodiments of this disclosure may provide solutions to these or other problems. For example, according to certain embodiments, a method and system are provided that enables a UE to receive information about the beam used in a target (second) logic DU during a RACH-less HO.

[0014] According to a particular embodiment, a method by UE for mIAB includes receiving information indicating a beam transmitted from a target DU during the HO of the UE from a first cell to a second cell. The HO includes an mIAB RACH-less HO.

[0015] According to a particular embodiment, a UE for the mIAB is configured to receive information indicating a beam transmitted from a target DU during the HO of the UE from a first cell to a second cell. The HO includes an mIAB RACH-less HO.

[0016] According to a particular embodiment, the method by source CU for mIAB includes transmitting to the UE information indicating a beam transmitted from a target DU during the HO of the UE from a first cell to a second cell. The HO includes an mIAB RACH-less HO.

[0017] According to a particular embodiment, the source CU for the mIAB is configured to transmit to the UE information indicating the beam transmitted from the target DU during the HO of the UE from the first cell to the second cell. The HO includes the mIAB RACH-less HO.

[0018] According to a particular embodiment, the method using a target CU for mIAB is This includes receiving from and / or transmitting to the source CU information indicating the beam transmitted from the target DU during the HO of the UE from the first cell to the second cell. The HO includes mIAB RACH-less HO.

[0019] According to a particular embodiment, the target CU for the mIAB is configured to receive from and / or transmit to the source CU information indicating the beam transmitted from the target DU during the HO of the UE from the first cell to the second cell. The HO includes the mIAB RACH-less HO.

[0020] A particular embodiment may provide one or more of the following technical advantages. For example, a particular embodiment may provide the technical advantage of enabling the network to determine the appropriate beam to be used by the UE (due to DU migration) during a mobile IAB RACH-less handover. As another example, a particular embodiment may provide the technical advantage of enabling the UE to complete the mobile IAB RACH-less handover procedure without handover failure and to avoid a prolonged connection interruption.

[0021] Other advantages may be readily apparent to those skilled in the art. Certain embodiments may have none, some, or all of the advantages described. [Brief explanation of the drawing]

[0022] For a more complete understanding of the disclosed embodiments, and their features and advantages, reference is made herein to the following description taken in conjunction with the accompanying drawings below.

[0023] [Figure 1] Figure 1 shows an mIAB mounted on a bus traveling along a route covered by four different parent IAB nodes. [Figure 2] Figure 2 shows UE handover (HO) between cells associated with different logical IAB-DUs connected to separate CUs. [Figure 3] Figure 3 shows an exemplary method and signaling diagram for a network to determine which beam a UE should use toward a second logical mIAB-DU and notify the UE thereof, in accordance with certain embodiments. [Figure 4] Figure 4 shows an exemplary flow and signaling diagram, comprising a source donor CU calculating and / or determining a beam to be used by a UE during mIAB RACH-less HO, in accordance with certain embodiments. [Figure 5] Figure 5 shows an exemplary flow and signaling diagram, comprising a target donor CU calculating and / or determining a beam to be used by a UE during mIAB RACH-less HO, in accordance with certain embodiments. [Figure 6] Figure 6 shows an exemplary communication system in accordance with certain embodiments. [Figure 7] Figure 7 shows an exemplary UE in accordance with certain embodiments. [Figure 8] Figure 8 shows an exemplary network node in accordance with certain embodiments. [Figure 9] Figure 9 shows a virtualized environment in which functions implemented by some embodiments may be virtualized, in accordance with certain embodiments. [Figure 10] Figure 10 shows an exemplary method performed by a UE for mIAB in accordance with certain embodiments. [Figure 11] Figure 11 shows an exemplary method performed by a CU for indicating at least one access beam for mIAB, in accordance with certain embodiments. [Figure 12] Figure 12 shows an exemplary method by a target CU for indicating at least one access beam for an mIAB according to a particular embodiment. [Figure 13] Figure 13 shows an exemplary method by UE for mIAB according to a specific embodiment. [Figure 14] Figure 14 shows an exemplary method 1200 by source CU for mIAB according to a particular embodiment. [Figure 15] Figure 15 shows a method for mIAB using a target CU according to a specific embodiment. [Modes for carrying out the invention]

[0024] Some of the embodiments described herein will be described in more detail below with reference to the accompanying drawings. The embodiments are provided as examples to convey the scope of the subject to those skilled in the art.

[0025] As used herein, “node” may be a network node or an UE. Examples of network nodes include Node B, Base Station (BS), Multi-Standard Radio (MSR) such as MSR BS, eNode B (eNB), gNode B (gNB), Master eNB (MeNB), Secondary eNB (SeNB), Integrated Access Backhaul (IAB) nodes, Network Controller, Radio Network Controller (RNC), Base Station Controller (BSC), Relays, Donor Node Control Relays, Base Transmitting Stations (BTS), Central Unit (e.g., within a gNB), Distributed Unit (e.g., within a gNB), Baseband Unit, Centralized Baseband, Central Baseband, C-RAN, Access Point (AP), Transmitting Point, Transmitting Node, Remote Radio Unit (RRU), Nodes within a Distributed Antenna System (DAS), Core Network Nodes (e.g., Mobile Switching Center (MSC), Mobility Management Entity (MME), etc.), Operation & Maintenance (O&M), Operation Support System (OSS), Self-Organizing Network (SON), Positioning Node (e.g., e-SMLC), etc.

[0026] Another example of a node is the non-restrictive term User Equipment (UE), which refers to any type of wireless device that communicates with network nodes and / or other UEs in a cellular or mobile communication system. Examples of UEs include target devices, device-to-device (D2D) UEs, vehicle-to-vehicle (V2V) UEs, machine-type UEs, MTC UEs or UEs capable of machine-to-machine (M2M) communication, personal digital assistants (PDAs), tablets, mobile terminals, smartphones, laptop embedded devices (LEEs), laptop-mounted devices (LMEs), Unified Serial Bus (USB) dongles, etc.

[0027] In some embodiments, the general term “wireless network node” or simply “network node (NW node)” is used. It can be any kind of network node, including base stations, wireless base stations, base transceivers, base station controllers, network controllers, evolved Node B (eNB), Node B, gNodeB (gNB), relay nodes, access points, wireless access points, remote radio units (RRUs), remote radio heads (RRHs), central units (e.g., within a gNB), distributed units (e.g., within a gNB), baseband units, centralized baseband, C-RAN, access points (APs), etc.

[0028] The term "Radio Access Technology (RAT)" can refer to any RAT, such as Universal Terrestrial Radio Access Network (UTRA), Evolved Universal Terrestrial Radio Access Network (E-UTRA), Narrowband Internet of Things (NB-IoT), WiFi, Bluetooth, Next Generation RAT, NR, 4G, 5G, etc. Any device referred to by the terms node, network node, or radio network node may support one or more RATs.

[0029] As used herein, the terms signal or radio signal may refer to any physical signal or physical channel. Examples of downlink (DL) physical signals include reference signals (RS) such as the primary synchronization signal (PSS), secondary synchronization signal (SSS), channel status information-reference signal (CSI-RS), demodulation reference signal (DMRS) in an SS / PBCH block (SSB), discovery reference signal (DRS), cell-specific reference signal (CRS), and positioning reference signal (PRS). RS may be periodic. For example, an RS opportunity carrying one or more RS may occur at a certain period (e.g., 20 ms, 40 ms, etc.). RS may also be non-periodic.

[0030] Each SSB carries the New Radio-Primary Synchronization Signal (NR-PSS), New Radio-Secondary Synchronization Signal (NR-SSS), and New Radio-Physical Broadcast Channel (NR-PBCH) in four consecutive symbols. One or more synchronization signal blocks (SSBs) are transmitted in a single SSB burst that repeats at specific periodicities, such as 5ms, 10ms, 20ms, 40ms, 80ms, and 160ms. The UE is configured with information about SSBs on a cell at a specific carrier frequency by one or more SS / PBCH block measurement timing settings (SMTC) settings. SMTC settings include parameters such as SMTC periodicity, SMTC opportunity length in time or duration, and SMTC time offset with respect to a reference time (e.g., the serving cell's SFN). Thus, SMTC opportunities can also occur at specific periods (e.g., 5ms, 10ms, 20ms, 40ms, 80ms, and 160ms). Examples of uplink (UL) physical signals include reference signals such as the Sounding Reference Signal (SRS) and Demodulation Reference Signal (DMRS). The term "physical channel" refers to any channel that carries higher-layer information (e.g., data, control, etc.). Examples of physical channels include physical broadcast channels (PBCH), physical downlink control channels (PDCCH), physical downlink shared channels (PDSCH), physical uplink shared channels (PUSCH), physical uplink control channels (PUCCH), physical uplink shared channels (PUSCH), short PUSCH (sPUSCH), short PDSCH (sPDSCH), short PUCCH (sPUCCH), short PUSCH (sPUSCH), MTC PDCCH (MPDCCH), narrowband PBCH (NPBCH), narrowband PDCCH (NPDCCH), narrowband PDSCH (NPDSCH), narrowband PUSCH (NPUSCH), and extended PDCCH (E-PDCCH).

[0031] As used herein, the term "time resource" may refer to any type of physical or wireless resource expressed in terms of a length of time. Examples of time resources include symbols, time slots, subframes, wireless frames, TTI, interleaved time, slots, subslots, minislots, system frame number (SFN) cycles, hyper-SFN (H-SFN) cycles, etc.

[0032] In this specification, the terms “mIAB,” “mobile IAB,” and “mIAB node” are used interchangeably.

[0033] In this specification, the terms “mIAB-DU,” “Mobile DU,” and “DU” are used interchangeably.

[0034] In this specification, the terms "first / second logical mIAB-DU" and "source / target mIAB-DU" are used interchangeably.

[0035] In this specification, the terms Mobile IAB-MT and mIAB-MT are used interchangeably.

[0036] In this specification, the terms Mobile IAB-DU and mIAB-DU are used interchangeably.

[0037] In this specification, the terms "CU," "donor CU," and "donor node" are used interchangeably.

[0038] In this specification, the term "NG / S1 interface" means "NG interface or S1 interface." The same applies to "X2 / Xn interface."

[0039] In this specification, the terms "NG" and "NGAP," and the terms "Xn" and "XnAP" are used interchangeably.

[0040] In this specification, the term “UE connected to a mobile IAB” is used to characterize a UE that is within the coverage provided by a mobile IAB node.

[0041] In this specification, the term "RACH-less HO" refers to an HO performed without executing the RACH procedure.

[0042] While specific embodiments are described in the context of NR, the embodiments, techniques, solutions, and methods described herein can be applied without loss of meaning to other radio access technologies that utilize mobile IAB nodes.

[0043] In this specification, the term “information related to UE RACH-less handover” includes, but is not limited to, UE measurement reports, selected beam indices, beam RSRP, and corresponding target cell PCI.

[0044] As described above, according to previous HO techniques (i.e., L3), it is usually the UE that determines which beam to use for the target cell during the RACH procedure. However, if the RACH procedure is not involved, it is impossible for the UE to determine which beam to use for the target (second) logical mIAB-DU. Therefore, according to certain embodiments disclosed herein, the network determines which beam the UE should use for the second logical mIAB-DU and then notifies the UE.

[0045] For example, according to certain embodiments, a method and system are provided to enable a UE to receive information about the beam used for the target (second) logical DU during a RACH-less HO. These methods and systems can be applied, for example, to an inter-CU mIAB-DU migration scenario using two logical DUs. Furthermore, according to certain embodiments, a method and system are provided for the network to determine which beam the UE should use when switching to the target (second) logical DU during a RACH-less handover (due to DU migration).

[0046] For example, according to a particular embodiment, upon receiving a measurement report from the UE, the source donor CU selects a beam to be used by the UE during a RACH-less handover for the mIAB and indicates this selected beam to the target donor CU when triggering the handover procedure.

[0047] As another example, according to a particular embodiment, upon receiving a measurement report from the UE, the source donor CU sends the measurement report to the target donor CU when triggering the HO procedure. The target donor CU then selects the beam to be used by the UE during the RACH-less handover for the mIAB.

[0048] Certain embodiments are described based on a scenario that assumes the migration of mobile IAB-DUs (mIAB-DUs) between donor CUs, in which the UEs served by the source logical mIAB-DU need to be handed over to the target logical mIAB-DU; however, the embodiments, techniques, solutions, and methods described herein are applicable to other scenarios.

[0049] Figure 3 shows an exemplary method and signaling diagram 100 for a network according to a particular embodiment to determine which beam UE 102 should use toward the second logical mIAB-DU 104 and to notify UE 102 of this.

[0050] As shown, method 100 is initiated in step 120, at which point UE 102 provides donor CU1 108 with a measurement report from the target beam emitted by logic DU2 104.

[0051] In step 130, donor CU1 108 provides either the selected beam or measurement report to donor CU2 112 via Xn or NG.

[0052] In step 140, donor CU2 112 includes the target beam in its handover response, which includes the TA value, if any, that UE 102 needs to adjust for the new beam. If no value is provided, UE 102 reuses the same TA from the old beam.

[0053] In step 150, donor CU1 108 transfers information, the selected beam, and any additional information from donor CU2 112 to UE 102.

[0054] In step 160, UE 102 migrates to donor CU2 112 (performs a handover).

[0055] Figure 4 shows an exemplary flow and signaling diagram 200, which includes the calculation and / or determination by the source donor CU 208 of the beam used by UE 202 during mIAB RACH-less HO, according to a particular embodiment.

[0056] As shown, the exemplary flowchart 200 includes step 220, in which UE 202 sends a measurement report to source donor CU 208 (via first logical mIAB DU 210). The measurement report may be sent periodically by UE 202 or when a specific event is triggered (e.g., channel intensity on serving cell falls below a threshold). The measurement report may also be triggered when mIAB migration is underway and all UEs are handed over to second logical DU 204.

[0057] In step 225, when the first logic mIAB DU 210 receives the measurement report from UE 202, it forwards it to the source donor CU 208 blindly (i.e., without reading or decoding).

[0058] In steps 230 and 235, upon receiving the UE measurement report, source donor CU 208 determines that a mobile IAB RACH-less handover should be triggered toward the selected target donor CU 212, and further determines which beam UE 202 will use if a mobile IAB RACH-less handover is triggered toward target donor DU 204.

[0059] In certain embodiments, the source donor CU 208 determines the beam according to or based on one or more of the following: ● The best beam (i.e., the beam with the strongest channel state) is selected as the final beam. ● A beam belonging to a specific PCI is selected as the final beam. ● A beam operating at a specific frequency is selected as the final beam. ● A beam belonging to a specific cell index is selected as the final beam. ● The beam with the strongest RSRP, RSRQ, SINR, or RSSI is selected as the final beam. ● The best beam not assigned to any other UE, according to any of the criteria described herein (this applies when the network wishes to assign a dedicated beam to each UE or a subset of UEs).

[0060] In this context, the beam is characterized according to one or more of the following: ● Beam identifier (ID), ● Transmission Configuration Identifier (TCI): Status ID, ●TCI status setting, ●SSB ID, and ●CSI-RS resource ID.

[0061] In step 240, when the source donor CU 208 determines which beam the UE will use if a mobile IAB RACH-less handover of UE 202 is triggered toward the target donor DU 204, it sends a handover request message to the selected target donor CU 212, including the beam that has just been determined.

[0062] In steps 245 and 250, the target donor CU 212 sends a request to the second logical mIAB DU 204 to establish a UE context for the upcoming mobile IAB RACH-less handover procedure, including the selected beams received by the source donor CU 208 with this request. The second logical mIAB DU 204 prepares the lower-layer configuration to be sent to the UE 202 as part of the handover command and sends it to the target donor CU 212, including the selected beams received by the target donor CU 212. In some cases, if UE 202 requires TA adjustment, a new TA value or delta adjustment may also be provided along with the selected beams, simply due to a known timing difference between the old and new beams (e.g., a new synchronization source adopted for the new logical DU2).

[0063] In step 255, the target donor CU 212 sends a handover command (i.e., an RRCReconfiguration message) to the source donor CU 208 to send to UE 202 to initiate the handover procedure toward the target donor CU 212 (and the second logical mIAB DU 204).

[0064] In step 260, source donor CU 208 sends handover commands to UE 202, including any adjustments received from target donor CU 212 (e.g., those related to TA).

[0065] Following this step, UE 212 initiates the mobile IAB RACH-less handover procedure by applying the received RRC reconfiguration message (which also includes an indication that this handover should be RACH-less). In this case, the random access procedure is not required, and UE 212 may, in step 265, initiate transmission and reception with the target donor CU 212 (and the second logical mIAB DU 204) via the beam indicated in the received RRC reconfiguration message.

[0066] Figure 5 shows an exemplary flow and signaling diagram 300, which includes the calculation and / or determination by the target donor CU 312 of the beam used by UE 302 during mIAB RACH-less HO according to a particular embodiment. As shown in Figure 5, in step 325, UE 302 sends a measurement report to the source donor CU 308 (via the first logical mIAB DU 310). The measurement report may be sent periodically by UE 302 or because a specific event has been triggered (e.g., the channel intensity on the serving cell is below a threshold). The measurement report may also be triggered because mIAB migration is taking place and all UEs are being handed over to the second logical DU 304. In this latter case, a possible example is when a DU migration is performed (the mIAB DU migrates between source donor CU 308 and target donor CU 312), and a handover needs to be triggered for two or more UEs 302. Therefore, since source donor CU 308 may broadcast a "DU migration ongoing" indication, the UEs will know that they need to send a measurement report to the network in such a case.

[0067] In step 330, when the first logic mIAB DU 310 receives the measurement report from UE 302, it forwards it to the source donor CU 308 blindly (i.e., without reading or decoding).

[0068] In step 335, upon receiving the UE measurement report, the source donor CU 308 determines that a mobile IAB RACH-less handover to the selected target donor CU 312 should be triggered.

[0069] In step 340, the source donor CU 308 sends a handover request message to the selected target donor CU 312, including the measurement report received by UE 302 in the request.

[0070] According to various specific embodiments, the source donor CU 308 may decide to include one or more of the following as part of the measurement report when transmitting the measurement report: ●The entire measurement report received by UE 302, ●Measurement results related to target donor CU 312 (part of the measurement report), ●Measurement results related to specific cells belonging to target donor CU 312 (part of the measurement report), ●Measurement results related to all cells belonging to the second logic mIAB DU 304 (which are part of the measurement report), and ●Measurement results related to one cell belonging to the second logic mIAB DU 304 (part of the measurement report).

[0071] Furthermore, the source-donor CU 308 may include, along with the measurement report received by UE 302, recommendations for beams that UE 302 may use during the mobile IAB RACH-less handover procedure.

[0072] In certain embodiments, the source-donor CU 308 determines the beam according to one or more of the following: ● The best beam (i.e., the beam with the strongest channel state) is selected as the final beam. ● A beam belonging to a specific PCI is selected as the final beam. ● A beam operating at a specific frequency is selected as the final beam. ● A beam belonging to a specific cell index is selected as the final beam. ● The beam with the strongest RSRP, RSRQ, SINR, or RSSI is selected as the final beam, and ● The best beam not assigned to any other UE, according to any of the criteria described herein (this applies when the network wishes to assign a dedicated beam to each UE or a subset of UEs).

[0073] In certain embodiments, the beam may be characterized according to one or more of the following: ● Beam ID, ●TCI status ID, ●TCI status setting, ●SSB ID, and ●CSI-RS resource ID.

[0074] In step 345, when the target donor CU 312 receives a handover request from the source donor CU 308, along with the measurement report received from UE 302 and the recommended beam that UE 302 should ultimately use when performing the mobile IAB RACH-less handover to the target donor CU 312, the target donor CU 312 determines which beam will be used by UE 302 when performing the mobile IAB RACH-less handover.

[0075] In certain embodiments, the target donor CU 312 determines the beam according to one or more of the following: ● The best beam (i.e., the beam with the strongest channel state) is selected as the final beam. ● A beam belonging to a specific PCI is selected as the final beam. ● A beam operating at a specific frequency is selected as the final beam. ● A beam belonging to a specific cell index is selected as the final beam. ● The beam with the strongest RSRP, RSRQ, SINR, or RSSI is selected as the final beam, and ● The beam recommended by the source donor CU is selected as the final beam.

[0076] In certain embodiments, the beam may be characterized according to one or more of the following: ● Beam ID, ●TCI status ID, ●TCI status setting, ●SSB ID, and ●CSI-RS resource ID.

[0077] In steps 350 and 355, the target donor CU 312 sends a request to the second logical mIAB DU 304 to establish a UE context for the upcoming mobile IAB RACH-less handover procedure, including the selected beam with this request. The second logical mIAB DU 304 prepares the lower layer configuration to be sent to UE 302 as part of the handover command and sends it to the target donor CU 312, including the selected beam received by the target donor CU 312. In some cases, if UE 302 requires TA adjustment, a new TA value or delta adjustment may also be provided along with the selected beam, simply due to a known timing difference between the old and new beams (e.g., a new synchronization source adopted for the new logical DU2).

[0078] In step 360, the target donor CU 312 sends a handover command (i.e., an RRCReconfiguration message) to the source donor CU 308, which should be sent to the UE 302 to initiate the handover procedure toward the target donor CU 312 (and the second logical mIAB DU 304).

[0079] In step 365, the source donor CU 308 sends a handover command to the UE 302, including any adjustments received by the target donor CU 312 (e.g., those related to TA).

[0080] Following this step, UE 302 initiates the mobile IAB RACH-less handover procedure by applying the received RRC reconfiguration message (which also includes an indication that this handover should be RACH-less). In this case, the random access procedure is not required, and UE 302 may, in step 365, begin sending and receiving with the target donor CU 312 (and the second logical mIAB DU 304) via the beam indicated in the received RRC reconfiguration message.

[0081] According to a specific embodiment, the source donor CU 308 may transmit information related to RACH-less handover (HO) of a single UE 302 to the target donor CU 312 in a single message. This beam-related information may be transmitted via legacy UE-related signaling such as HANDOVER PROCEDURES.

[0082] In other embodiments, the source donor CU 308 may transmit information related to RACH-less HO of a plurality of UEs 302 to the target donor CU 312 in a single message. This beam information of the plurality of UEs 302 may be transmitted via legacy IAB-related procedures or a new procedure specialized for HO of the plurality of UEs 302.

[0083] <NGAP-related aspects> In the specific embodiments described above, Xn-based UE handover was assumed. However, 3GPP specifications also support NG-based handover when there is no XnAP connection between the source node and the target node. According to the specifications, in this case, the source and target RAN nodes exchange messages related to UE HO via the NGAP interface with one AMF interposed therebetween (when the AMF serves both the source node and the target node), or with two or more AMFs interposed therebetween (when different AMFs serve the source node and the target node, respectively).

[0084] In some embodiments, all considerations, techniques, embodiments, solutions, methods, etc. presented for the case of Xn-based handover are equally applicable to the case of NG-based UE handover.

[0085] <Impact on technical specifications> All implementation examples are non-exclusive. Proposed changes are indicated in bold / underline. The added content may be in the form of multiple IEs or a single IE consisting of one or more IEs. In some embodiments, the newly added IE in the example may include a list of UE measurements related to one or more UEs, while in some embodiments it may include a single UE measurement.

[0086] Example of RRC implementation in TS 38.331 v17.5.0 An example of modifying ASN.1 RRCReconfiguration is provided below.

[0087] TIFF2026530420000002.tif35154

[0088] XnAP implementation example in TS 38.423 v17.5.0 An example of the changes is provided below.

[0089] 9.1.1.1 HANDOVER REQUEST This message is sent by the source NG-RAN node to the target NG-RAN node to request the preparation of resources for handover. Direction: Source NG-RAN node → Target NG-RAN node

[0090] TIFF2026530420000003.tif85154TIFF2026530420000004.tif213154TIFF2026530420000005.tif215154TIFF2026530420000006.tif127154

[0091] NGAP implementation example in TS 38.413 v17.5.0 An example of modifying ASN.1 RRCReconfiguration is provided below.

[0092] 9.3.1.29 Transparent containers from source NG-RAN node to target NG-RAN node This IE is generated by the source NG-RAN node and sent to the target NG-RAN node. In the case of inter-system handover to 5G, the IE is sent from the external handover source to the target NG-RAN node. This version of IE is transparent to 5GC.

[0093] TIFF2026530420000007.tif205139TIFF2026530420000008.tif195139TIFF2026530420000009.tif214139

[0094] Figure 6 shows an example of a communication system 400 according to several embodiments. In this example, the communication system 400 includes a telecommunications network 402 which includes an access network 404 such as a radio access network (RAN) and a core network 406 which includes one or more core network nodes 408. The access network 404 includes one or more access network nodes such as network nodes 410a and 410b (one or more of which may generally be referred to as network node 410), or some other similar third-generation partnership project (3GPP) access node or non-3GPP access point. The network nodes 410 facilitate direct or indirect connectivity of user equipment (UEs) by connecting UEs 412a, 412b, 412c and 412d (one or more of which may generally be referred to as UE412) to the core network 406 over one or more wireless connections.

[0095] Exemplary wireless communications on a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for carrying information without using wires, cables, or other physical conductors. Furthermore, in various embodiments, the communication system 400 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that can facilitate or participate in the communication of data and / or signals, whether wired or wireless. The communication system 400 may include and / or interface with any type of communication, telecommunications, data, cellular, wireless network, and / or other similar types of systems.

[0096] UE412 may be any of a broad range of communication devices, including wireless devices that are arranged, configured, and / or operable to communicate wirelessly with network node 410 and other communication devices. Similarly, network node 410 is arranged, can communicate, is configured, and / or operable to communicate directly or indirectly with UE412 and / or other network nodes or devices in telecommunications network 402 in order to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as management within telecommunications network 402.

[0097] In the illustrated example, the core network 406 connects network node 410 to one or more hosts, such as host 416. These connections may be direct or indirect, via one or more intermediate networks or devices. In other examples, network nodes may be directly connected to hosts. The core network 406 includes one or more core network nodes (e.g., core network node 408) structured with hardware and software components. The functions of these components may be substantially the same as those described for the UE, network nodes, and / or hosts, and therefore those descriptions are generally applicable to the corresponding components of core network node 408. An exemplary core network node includes one or more of the following functions: Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier Decryption Function (SIDF), Unified Data Management (UDM), Security Edge Protected Proxy (SEPP), Network Exposure Function (NEF), and / or User Plane Function (UPF).

[0098] Host 416 may be owned by or under the control of a service provider other than the operator or provider of the access network 404 and / or the telecommunications network 402, and may be operated by or on behalf of such service provider. Host 416 may host a variety of applications and provide one or more services. Examples of such applications include live and pre-recorded audio / video content, data acquisition services such as acquisition and editing of data on a variety of ambient conditions detected by multiple UEs, analytical functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for alarm and monitoring centers, or any other such functions performed by a server.

[0099] Overall, the communication system 400 in Figure 6 enables connectivity between the UE, network nodes, and hosts. In this sense, the communication system may be configured to operate according to predefined rules or procedures, such as certain standards, including but not limited to: GSM (Global System for Mobile Communications), UMTS (Universal Mobile Telecommunications System), LTE (Long Term Evolution), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standards (e.g., 6G), WLAN (wireless local area network) standards such as the IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard (WiFi), and / or any other suitable wireless communication standards such as WiMax (Worldwide Interoperability for Microwave Access), Bluetooth, Z-Wave, NFC (Near Field Communication), ZigBee, LiFi, and / or any LPWAN (low-power wide-area network) standards such as LoRa and Sigfox.

[0100] In some examples, the telecommunications network 402 is a cellular network implementing functions standardized by 3GPP. Therefore, the telecommunications network 402 may support network slicing to provide various logical networks to various devices connected to the telecommunications network 402. For example, the telecommunications network 402 may provide ultra-high reliability low latency communication (URLLC) services to some UEs while providing extended mobile broadband (eMBB) services to other UEs, and / or provide massive machine type communication (mMTC) / massive IoT services to further UEs.

[0101] In some examples, UE412 is configured to transmit and / or receive information without direct human interaction. For example, the UE may be designed to transmit information to access network 404 on a predetermined schedule, triggered by internal or external events, or in response to a request from access network 404. Additionally, the UE may be configured to operate in single or multi-RAT, or multi-standards mode. For example, the UE may be configured to operate in any one or a combination of Wi-Fi, NR (New Radio), and LTE, i.e., for multi-radio dual connectivity (MR-DC) such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio-Dual Connectivity (EN-DC).

[0102] In the above example, the hub 414 communicates with the access network 404 to facilitate indirect communication between one or more UEs (e.g., UE412c and / or 412d) and a network node (e.g., network node 410b). In some examples, the hub 414 may be a controller, router, content source and analytics, or any other communication device described herein with respect to the UE. For example, the hub 414 may be a broadband router that enables the UE to access the core network 406. In another example, the hub 414 may be a controller that sends commands or instructions to one or more actuators within the UE. Commands or instructions may be received from the UE or network node 410, or accepted by executable code, scripts, processes, or other instructions within the hub 414. In yet another example, the hub 414 may be a data collector acting as temporary storage for the UE's data, which in some embodiments may perform analysis or other processing on that data. In yet another example, the hub 414 may be a content source. For example, with respect to a UE that is a VR headset, display, loudspeaker, or other media delivery device, the hub 414 may acquire media or data related to VR assets, video, audio, or other sensory information via network nodes, in which case the hub 414 provides it to the UE either directly, after performing local processing, and / or after adding additional local content. In another example, the hub 414 acts as a proxy server or orchestrator for the UE, in particular when one or more of the UEs are low-energy IoT devices.

[0103] Hub 414 may have a steady / permanent or intermittent connection to network node 410b. Furthermore, Hub 414 may enable different communication methods and / or schedules between Hub 414 and UEs (e.g., UE412c and / or 412d), and between Hub 414 and the core network 406. In other examples, Hub 414 is connected to the core network 406 and / or one or more UEs via a wired connection. Additionally, Hub 414 may be configured to connect to an M2M service provider on the access network 404 and / or to other UEs via a direct connection. In some scenarios, a UE may establish a wireless connection with network node 410 while still being connected via Hub 414 via a wired or wireless connection. In some embodiments, Hub 414 may be a dedicated hub, i.e., a hub whose primary function is to route communication between UEs and network node 410b. In other embodiments, the hub 414 may be a non-dedicated hub, i.e., a device capable of routing communication between the UE and the network node 410b, but also capable of acting as a source and / or destination for some data channel.

[0104] Figure 7 shows several embodiments of the UE500. As used herein, UE refers to a device that is capable of, configured, deployed, and / or operating wirelessly with network nodes and / or other UEs. Examples of UEs include, but are not limited to, smartphones, mobile phones, cell phones, VoIP (Voice over IP) phones, wireless local loop phones, desktop computers, personal digital assistants (PDAs), wireless cameras, game consoles or devices, music storage devices, playback appliances, wearable terminal devices, wireless endpoints, mobile stations, tablets, laptops, laptop embedded devices (LEEs), laptop-based devices (LMEs), smart devices, wireless customer premises equipment (CPEs), and in-vehicle or vehicle embedded / integrated wireless devices. Other examples include any UE identified by the Third Generation Partnership Project (3GPP), including Narrowband Internet of Things (NB-IoT) UEs, Machine Type Communications (MTC) UEs, and / or Enhanced MTC (eMTC) UEs.

[0105] A UE may support device-to-device (D2D) communication, for example, by implementing 3GPP standards for side-link communication, dedicated short-range communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE does not necessarily have a user in the sense of a person who owns and / or operates the device in question. Instead, a UE may represent a device (e.g., a smart sprinkler controller) that is intended to be sold to or operated by a human user, but may not be associated with a particular human user, at least initially. Alternatively, a UE may represent a device (e.g., a smart power meter) that is not intended to be sold to or operated by an end user, but may be associated with a user or operated for the benefit of a user.

[0106] The UE500 includes an input / output interface 506, a power supply 508, memory 510, a communication interface 512, and / or any other components, or any combination thereof, and processing circuits 502 operably connected via bus 504. A certain UE may utilize all or a subset of the components shown in Figure 7. The level of integration between components may vary between one UE and another. Furthermore, a certain UE may include multiple instances of a component, such as multiple processors, memory, transceivers, transmitters, receivers, etc.

[0107] The processing circuit 502 is configured to process instruction sets and data, and may implement some sequential state machine capable of operating to execute instruction sets stored in memory 510 as machine-readable computer programs. The processing circuit 502 may be implemented as one or more hardware-implemented state machines (e.g., discrete logic, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), etc.), programmable logic with appropriate firmware, one or more stored computer programs, a general-purpose processor such as a microprocessor or digital signal processor (DSP) with appropriate software, or any combination of the above. For example, the processing circuit 502 may include multiple central processing units (CPUs).

[0108] In the above example, the input / output interface 506 may be configured to provide an input device, an output device, or one or more interfaces to one or more input and / or output devices. Examples of output devices include speakers, sound cards, video cards, displays, monitors, printers, actuators, emitters, smart cards, other output devices, or any combination thereof. Input devices may allow a user to capture information to the UE500. Examples of input devices include touch-sensitive or presence-sensitive displays, cameras (e.g., digital cameras, digital video cameras, webcams, etc.), microphones, sensors, mice, trackballs, directional pads, trackpads, scroll wheels, and smart cards. Presence-sensitive displays may include capacitive or resistive touch sensors for sensing user input. Sensors may include, for example, accelerometers, gyroscopes, tilt sensors, force sensors, magnetic sensors, optical sensors, proximity sensors, biosensors, or any combination thereof. Output devices may use the same type of interface port as input devices. For example, a Universal Serial Bus (USB) port may be used to provide input and output devices.

[0109] In some embodiments, the power supply 508 is structured as a battery or battery pack. Other types of power sources may be used, such as an external power source (e.g., an electrical outlet), a solar power device, or a battery. The power supply 508 may further include power circuits for transmitting power from the power supply 508 itself and / or an external power source to various parts of the UE500 via interfaces such as input circuits or power cables. Power transmission may be, for example, for charging the power supply 508. The power circuits may perform some shaping, conversion, or other modification on the power from the power supply 508 to suit the power of each component of the UE500 to which the power is supplied.

[0110] Memory 510 may be, or may be configured to include, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, and flash drives. In one example, memory 510 includes one or more application programs 514, such as an operating system, a web browser application, a widget, a gadget engine, or other application, and corresponding data 516. Memory 510 may store any of a wide variety of operating systems or combinations of multiple operating systems for use by UE500.

[0111] Memory 510 may be configured to include multiple physical drive units such as RAID (Redundant Array of Independent Disks), flash memory, USB flash drives, external hard disk drives, thumb drives, pen drives, key drives, HD-DVD (High-Density Digital Versatile Disc), optical disc drives, internal hard disk drives, Blu-ray optical disc drives, HDDS (Holographic Digital Data Storage) optical disc drives, external miniDIMM (Dual In-Line Memory Module), SDRAM (Synchronous Dynamic Random Access Memory), external microDIMM SDRAM, tamper-resistant modules in the form of UICC (universal integrated circuit card) including one or more SIMs (subscriber identity modules) such as USIM and / or ISIM, other memories, or any combination thereof. The UICC may be, for example, an embedded UICC (eUICC), an integrated UICC (iUICC), or a removable UICC commonly known as a "SIM card". The memory 510 may enable the UE500 to access instruction sets and application programs stored in temporary or non-temporary storage media to offload or upload data. Product items, such as those utilizing communication systems, may be tangibly embodied as or within the memory 510, which is a device-readable storage medium or may contain one.

[0112] The processing circuit 502 may be configured to communicate with an access network or other network using a communication interface 512. The communication interface 512 may include one or more communication subsystems, and may include or be communicatively connected to an antenna 522. The communication interface 512 may include one or more transceivers used to perform communication, such as by communicating with one or more remote transceivers of other wirelessly communicable devices (e.g., other UEs or network nodes in the access network). Each transceiver may include a transmitter 518 and / or receiver 520 appropriate for providing network communication (e.g., optical, electrical, frequency-allocated, etc.). Furthermore, the transmitter 518 and receiver 520 may be connected to one or more antennas (e.g., antenna 522), and they may share circuit components, software, or firmware, or alternatively, be implemented separately.

[0113] In the illustrated embodiment, the communication functions of the communication interface 512 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, near-field communication such as Bluetooth, location-based communication such as the use of GPS (Global Positioning System) for location determination, other similar communication functions, or any combination thereof. The communication may be implemented in accordance with one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA®), GSM, LTE, New Radio (NR), UMTS, WiMAX, Ethernet, Transmission Control Protocol / Internet Protocol (TCP / IP), Synchronous Optical Networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, and Hypertext Transfer Protocol (HTTP).

[0114] Regardless of the sensor type, the UE may provide an output of data captured by its sensor to a network node via a wireless connection through its communication interface 512. The data captured by the UE's sensor may be communicated to a network node via another UE via a wireless connection. The output may be periodic (e.g., once every 15 minutes if reporting sensed temperature), random (e.g., to equalize the load from notifications from multiple sensors), in response to a triggering event (e.g., moisture is detected and an alert is sent), in response to a request (e.g., a user-initiated request), or as a continuous stream (e.g., a live video feed of a patient).

[0115] Other examples include actuators, motors, or switches associated with a communication interface configured to receive wireless input from a network node via a wireless connection. The state of the actuator, motor, or switch may change in response to the received wireless input. For example, the UE may include a motor that adjusts the control surface or rotor of a drone in flight according to the received input, or a robotic arm that performs a medical procedure according to the received input.

[0116] If a UE is in the form of an IoT (Internet of Things) device, it may be a device for use in one or more application domains, which include, but are not limited to, wearable technology in urban environments, augmented industrial applications, and healthcare. Non-exclusive examples of such IoT devices include, or are incorporated into, devices such as connected refrigerators or freezers, TVs, connected lighting fixtures, electric meters, robotic vacuum cleaners, voice-controlled smart speakers, home security cameras, motion detectors, thermostats, smoke detectors, door / window sensors, moisture detectors (flood / moisture sensors), electric door locks, connected doorbells, air conditioning systems such as heat pumps, autonomous vehicles, surveillance systems, weather monitoring devices, vehicle parking monitoring devices, electric vehicle charging stations, smartwatches, fitness trackers, head-mounted displays for augmented reality (AR) or virtual reality (VR), wearables for haptic enhancement or sensory enhancement, water sprinklers, animal or object tracking devices, sensors for monitoring plants or animals, industrial robots, unmanned aerial vehicles (UAVs), and any type of medical device such as heart rate monitors or remotely controlled surgical robots. An IoT device-type UE comprises, in addition to circuitry and / or software that depends on the intended application of the IoT device, other components such as those described in relation to the UE500 shown in Figure 7.

[0117] In another specific example, in an IoT scenario, the UE may represent a machine or other device that performs monitoring and / or measurement and transmits the results of such monitoring and / or measurement to other UEs and / or network nodes. In this case, the UE may be an M2M device and may be referred to as an MTC device in the context of 3GPP. In one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, the UE may represent a vehicle such as a passenger car, bus, truck, ship or aircraft, or other equipment capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0118] In practice, any number of UEs may be used together for a single use case. For example, the first UE may be a drone or integrated into a drone and provide speed information of the drone (obtained through a speed sensor) to a second UE, which is a remote controller operating the drone. When the user makes a change from the remote controller, the first UE may adjust the drone's throttle (for example, by controlling an actuator) to increase or decrease the drone's speed. The first and / or second UE may include more than one of the functionalities described above. For example, the UE may include sensors and actuators and handle data communication for both the speed sensor and the actuator.

[0119] Figure 8 shows network nodes 600 according to several embodiments. As used herein, a network node is a device that is capable of communicating directly or indirectly with the UE and / or other network nodes or devices in the telecommunications network, and is configured, positioned, and / or capable of operating in such a manner. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points) and base stations (BSs) (e.g., radio base stations, node Bs, evolved node Bs (eNBs), and NR node Bs (gNBs)).

[0120] Base stations may be categorized based on the amount of coverage they provide (or, in other words, their transmit power level), and therefore may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations, depending on the amount of coverage they provide. A base station may also be a relay node or a relay donor node controlling a relay device. Network nodes may also include one or all of the parts of a distributed radio base station, such as a centralized digital unit and / or a remote radio unit (RRU), sometimes called a remote radio head (RRH). Such remote radio units may or may not be integrated with an antenna, such as an antenna-integrated radio. Some parts of a distributed radio base station may also be referred to as nodes within a distributed antenna system (DAS).

[0121] Other examples of network nodes include multi-transmitting point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BS, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base station transceivers (BTSs), transmit points, transmit nodes, multi-cell / multicast cooperative entities (MCEs), operation and maintenance (O&M) nodes, operation support system (OSS) nodes, self-organizing network (SON) nodes, and positioning nodes (including, for example, evolved serving mobile location centers (E-SMLCs) and / or drive test minimization (MDTs)).

[0122] Network node 600 includes a processing circuit 602, memory 604, a communication interface 606, and a power supply 608. Network node 600 may consist of multiple physically separate components (e.g., node B component and RNC component, or BTS component and BSC component), each of which may have its own respective components. In a scenario in which network node 600 has multiple separate components (e.g., BTS and BSC components), one or more of these separate components may be shared among several network nodes. For example, a single RNC may control multiple node Bs. In such a scenario, each unique pair of node B and RNC may, in some examples, be considered a single separate network node. In some embodiments, network node 600 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be redundant (e.g., separate memory 604 for different RATs), and some components may be reused (e.g., the same antenna 610 may be shared by multiple different RATs). Furthermore, the network node 600 may include multiple sets of diverse exemplary components for various wireless technologies to be integrated into the network node 600, such as GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, RFID (Radio Frequency Identification), or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chips or sets of chips and other components within the network node 600.

[0123] The processing circuit 602 may include one or more combinations of microprocessors, controllers, microcontrollers, central processing units, digital signal processors, application-specific integrated circuits, field-programmable gate arrays, or other suitable computing devices, resources, or hardware, software, and / or coding logic, which can operate independently or in conjunction with other network node 600 components such as memory 604 to provide the functionality of the network node 600.

[0124] In some embodiments, the processing circuit 602 includes a system-on-a-chip (SOC). In some embodiments, the processing circuit 602 includes one or more of the radio frequency (RF) transceiver circuit 612 and the baseband processing circuit 614. In some embodiments, the RF transceiver circuit 612 and the baseband processing circuit 614 may be on separate chips (or sets of chips), substrates, or units, such as a radio unit and a digital unit. In alternative embodiments, some or all of the RF transceiver circuit 612 and the baseband processing circuit 614 may be on the same chip or set of chips, substrate, or unit.

[0125] Memory 604 may include, but is not limited to, any form of volatile or non-volatile computer-readable memory, including persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random-access memory (RAM), read-only memory (ROM), large storage media (e.g., hard disk), removable storage media (e.g., flash drive, compact disc (CD) or digital video disc (DVD)), and / or any other volatile or non-volatile non-temporary device-readable and / or computer-executable memory device, for storing information, data and / or instructions that can be used by the processing circuit 602. Memory 604 may store any suitable instructions, data or information, including applications, and / or other instructions, which can be executed by the processing circuit 602 and are available to the network node 600, including one or more computer programs, software, logic, rules, code, and tables. Memory 604 may also be used to store any calculation results produced by the processing circuit 602 and / or any data received via the communication interface 606. In some embodiments, the processing circuit 602 and the memory 604 are integrated.

[0126] The communication interface 606 is used for wired or wireless signaling and / or data between network nodes, access networks, and / or UEs. As illustrated, the communication interface 606 includes, for example, a port / terminal 616 for sending and receiving data to and from the network over a wired connection. The communication interface 606 also includes a wireless front-end circuit 618, which is connected to or, in some embodiments, part of the antenna 610. The wireless front-end circuit 618 includes a filter 620 and an amplifier 622. The wireless front-end circuit 618 may be connected to the antenna 610 and the processing circuit 602. The wireless front-end circuit may be configured to adjust signals communicated between the antenna 610 and the processing circuit 602. The wireless front-end circuit 618 can receive digital data to be sent to other network nodes or UEs via the wireless connection. The wireless front-end circuit 618 can convert its digital data into a wireless signal with appropriate channel and bandwidth parameters using a combination of the filter 620 and / or the amplifier 622. The radio signal can then be transmitted via antenna 610. Similarly, when data is received, antenna 610 collects the radio signal, which can then be converted into digital data by the radio front-end circuit 618. The digital data can then be passed to the processing circuit 602. In other embodiments, the communication interface may include different components and / or different combinations of components.

[0127] In one alternative embodiment, the network node 600 does not include a separate radio front-end circuit 618; rather, the processing circuit 602 includes the radio front-end circuit and is connected to the antenna 610. Similarly, in some embodiments, all or some of the RF transceiver circuits 612 are part of the communication interface 606. In yet another embodiment, the communication interface 606, as part of a radio unit (not shown), includes one or more ports or terminals 616, a radio front-end circuit 618, and an RF transceiver circuit 612, and the communication interface 606 communicates with a baseband processing circuit 614, which is part of a digital unit (not shown).

[0128] Antenna 610 may include one or more antennas or antenna arrays configured to transmit and / or receive wireless signals. Antenna 610 may be connected to a wireless front-end circuit 618 and may be any type of antenna capable of wirelessly transmitting and receiving data and / or signals. In one embodiment, antenna 610 is separate from the network node 600 and can be connected to the network node 600 through an interface or port.

[0129] The antenna 610, communication interface 606, and / or processing circuit 602 may be configured to perform any receiving operations and / or acquisition operations described herein as being performed by a network node. Any information, data, and / or signals may be received from the UE, other network nodes, and / or any other network equipment. Similarly, the antenna 610, communication interface 606, and / or processing circuit 602 may be configured to perform any transmitting operations described herein as being performed by a network node. Any information, data, and / or signals may be transmitted to the UE, other network nodes, and / or any other network equipment.

[0130] Power supply 608 provides power to the various components of network node 600 in a format suitable for each component (for example, at the voltage and current levels required for each component). Power supply 608 may further include, or be connected to, a power management circuit for supplying power to the components of network node 600 to perform the functions described herein. For example, network node 600 may be connectable to an external power source (e.g., a power grid, an electrical outlet) via an input circuit or interface such as an electrical cable, thereby allowing the external power source to supply power to the power circuit of power supply 608. As a further example, power supply 608 may include a power source in the form of a battery or battery pack connected to or integrated into the power circuit. The battery may provide backup power in case of failure of the external power source.

[0131] Embodiments of network node 600 may include additional components other than those shown in Figure 8 to provide a functional view of the network node, including any functionality necessary to support any of the functionalities described herein and / or any functionality necessary to support the subject matter described herein. For example, network node 600 may include user interface equipment that enables input of information to and output of information from network node 600. This may enable users to perform diagnostic, maintenance, repair, and other management functions on network node 600.

[0132] Figure 9 is a block diagram showing a virtualization environment 700 in which functions implemented by several embodiments can be virtualized.

[0133] In this context, virtualization means for generating a virtual version of a device or apparatus may include a virtualization hardware platform, storage devices, and networking resources. As used herein, virtualization can be applied to any of the devices or components thereof described herein and relates to implementation examples in which at least some of its functionality is implemented as one or more virtual components. Some or all of the functionality described herein may be implemented as virtual components run by one or more virtual machines (VMs) implemented within one or more virtual environments 700 hosted by one or more hardware nodes, such as network nodes, UEs, core network nodes, or hardware computing devices acting as hosts. Furthermore, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or a host), the node as a whole may be virtualized.

[0134] Application 702 (which may alternatively be called a software instance, virtual appliance, network function, virtual node, virtual network function, etc.) runs in a virtualized environment 700 to implement some of the features, functions and / or benefits of some of the embodiments disclosed herein.

[0135] Hardware 704 includes a processing circuit, memory for storing software and / or instruction sets executable by the hardware processing circuit, and / or hardware devices as described herein, such as network interfaces and input / output interfaces. The software is executed by the processing circuit to instantiate one or more virtualization layers 706 (also referred to as a hypervisor or virtual machine monitor (VMM)), provide VM708a and VM708b (one or more of which may generally be referred to as VM708), and / or perform any of the functions, features and / or benefits described herein in relation to some of the embodiments described herein. The virtualization layer 706 may present a virtual operating platform that appears to the VM708 as networking hardware.

[0136] VM708 includes virtual processing, virtual memory, virtual networking or interfaces, and virtual storage, and may be run by the corresponding virtualization layer 706. Various embodiments of instances of the virtual appliance 702 may be implemented in one or more of the VM708, and such implementation may be carried out in various ways. Hardware virtualization is referred to as network function virtualization (NFV) in several contexts. NFV can be used to consolidate many types of network equipment into industry-standard, high-capacity server hardware, physical switches, and physical storage that can reside in data centers and customer premises equipment.

[0137] In the context of NFV, VM708 may be a software implementation of a physical machine that runs a program as if it were running on a physical, non-virtualized machine. Each VM708, and the portion of hardware 704 on which the VM runs, whether dedicated hardware for that VM and / or hardware shared by that VM with other VMs, forms a separate virtual network element. Also in the context of NFV, the virtual network function is responsible for handling the specific network functions running in one or more VM708s at the top level of hardware 704 and corresponds to application 702.

[0138] Hardware 704 may be implemented in a standalone network node with general-purpose or specific components. Hardware 704 may implement some functions through virtualization. Alternatively, hardware 704 may be part of a larger hardware cluster (e.g., one in a data center or CPE) in which multiple hardware nodes cooperate and are managed via management and orchestration 710, which oversees, among other things, the lifecycle management of application 702. In some embodiments, hardware 704 is connected to one or more radio units, each including one or more transmitters and one or more receivers, which can be connected to one or more antennas. The radio units may communicate directly with other hardware nodes via one or more suitable network interfaces, or they may be used in combination with virtual components to provide radio capabilities to virtual nodes, such as radio access nodes or base stations. In some embodiments, some signaling can be provided in conjunction with the use of a control system 712, which may alternatively be used for communication between hardware nodes and radio units.

[0139] Figure 10 shows an exemplary method 800 by a UE for mIAB according to a particular embodiment. In the illustrated embodiment, the method includes a receiving step in 802. For example, in step 802, the UE may receive information indicating the beam used in the target DU during the UE's HO from the first cell to the second cell.

[0140] Figure 11 shows an exemplary method 900 by a CU for indicating at least one access beam for a mIAB according to a particular embodiment. In the illustrated embodiment, the method includes a transmission step in 902. For example, in step 902, the CU may transmit information to the UE indicating the beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0141] Figure 12 shows an exemplary method 1000 by a target CU for indicating at least one access beam for a mIAB according to a particular embodiment. In the illustrated embodiment, the method includes a receive and / or transmit step 1002. For example, in step 1002, the target CU may receive from and / or transmit to the source CU information indicating a beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0142] Figure 13 shows an exemplary method 1100 by a UE for mIAB according to a particular embodiment. As illustrated, the method includes step 1102 in which the UE receives information indicating a beam transmitted from a target DU during the HO of the UE from a first cell to a second cell. The HO includes an mIAB RACH-less HO.

[0143] In certain embodiments, the UE performs HO to the second cell without performing the RACH procedure.

[0144] In a particular embodiment, a beam is associated with at least one of a beam identifier, a TCI status identifier, a TCI status setting, an SSB ID, and a CSI-RS resource identifier, and / or the above information identifies the beam by at least one of the beam identifier, a TCI status identifier, a TCI status setting, an SSB ID, and a CSI-RS resource identifier.

[0145] In a particular embodiment, the UE receives at least one TA value for the beam transmitted from the target DU during the UE's HO from the first cell to the second cell, along with the above information.

[0146] In a particular embodiment, the above information is received from the source CU via the source DU.

[0147] In a particular embodiment, at least one of the following is true: target DU(104) is a target donor DU, source DU(110) is a source donor DU, target CU(112) is a target donor CU, and source CU(108) is a source donor CU.

[0148] In certain embodiments, at least one of the target DU and source DU is a logical DU.

[0149] In a particular embodiment, prior to receiving the above information, the UE receives a plurality of beams from the target DU, performs at least one measurement procedure based on each of the plurality of beams, and sends a measurement report to the source CU containing at least one value related to the at least one measurement performed by the UE for at least one of the plurality of beams from the target DU.

[0150] Figure 14 shows an exemplary method 1200 by a source CU for mIAB according to a particular embodiment. As illustrated, the method includes, in step 1402, the source CU transmitting information to the UE indicating the beam to be transmitted from the target DU during the handover of the UE from the first cell to the second cell. The HO includes an mIAB RACH-less HO.

[0151] In a particular embodiment, a beam is associated with at least one of a beam identifier, a TCI status identifier, a TCI status setting, an SSB ID, and a CSI-RS resource identifier, and / or the above information identifies the beam by at least one of the beam identifier, a TCI status identifier, a TCI status setting, an SSB ID, and a CSI-RS resource identifier.

[0152] In a particular embodiment, at least one TA value for a beam is transmitted to the UE along with information indicating the beam being transmitted by the target DU during the HO of the UE from the first cell to the second cell.

[0153] In certain embodiments, the above information is transmitted to the UE via the source DU.

[0154] In a particular embodiment, at least one of the following is true: target DU(104) is a target donor DU, source DU(110) is a source donor DU, target CU(112) is a target donor CU, and source CU(108) is a source donor CU.

[0155] In certain embodiments, at least one of the target DU and source DU is a logical DU.

[0156] In a particular embodiment, the source CU determines that an mIAB RACH-less handover should be triggered toward the target CU.

[0157] In certain embodiments, the source CU receives a measurement report associated with the UE before transmitting information to the UE. The measurement report includes at least one value associated with at least one measurement performed by the UE for at least one beam transmitted by the target DU.

[0158] In a particular embodiment, the source CU transmits a measurement report, or at least one value associated with the measurement report, to a target CU associated with the target DU, and receives from the target CU information indicating the beam transmitted from the target DU during the HO of the UE from the first cell to the second cell.

[0159] In certain embodiments, the source CU transmits a recommended beam to be transmitted from the target DU, along with a measurement report or at least one value associated with the measurement report.

[0160] In a particular embodiment, the recommended beam is selected by the source CU based on at least one of the following: a value indicating that the recommended beam has the best channel quality; that the recommended beam is associated with a particular PCI; that the recommended beam operates at a particular frequency and / or within a particular frequency range; that the recommended beam is associated with a particular cell index; that the recommended beam has the maximum reference signal received power, reference signal received quality, signal-to-interference noise ratio, and / or received signal strength indicator; that the recommended beam is not assigned to any other UE; and that the recommended beam is assigned to a subset of UEs to which the UE belongs.

[0161] In certain embodiments, the recommended beam is associated with and / or indicated by at least one of the following: a beam identifier, a TCI status identifier, a TCI status setting, an SSB identifier, and a CSI-RS resource identifier.

[0162] In certain embodiments, a measurement report, or at least one value associated with the measurement report, is sent to the target CU in or along with a handover request message.

[0163] In a particular embodiment, the source CU receives a handover response message from the target CU that includes information indicating the beam transmitted from the target DU.

[0164] In a particular embodiment, the response message includes at least one TA value for the beam transmitted from the target DU during the HO of the UE from the first cell to the second cell.

[0165] Figure 15 shows a method for mIAB using a target CU according to a particular embodiment. As illustrated, the method includes, in step 1302, the target CU receiving from and / or transmitting to the source CU information indicating the beam transmitted from the target DU during the HO of the UE from the first cell to the second cell. The HO includes an mIAB RACH-less HO.

[0166] In a particular embodiment, a beam is associated with at least one of a beam identifier, a TCI status identifier, a TCI status setting, an SSB ID, and a CSI-RS resource identifier, and / or the above information identifies the beam by at least one of the beam identifier, a TCI status identifier, a TCI status setting, an SSB ID, and a CSI-RS resource identifier.

[0167] In a particular embodiment, at least one TA value for a beam is transmitted to the UE along with information indicating the beam being transmitted by the target DU during the HO of the UE from the first cell to the second cell.

[0168] In a particular embodiment, at least one of the following is true: target DU is target donor DU, source DU is source donor DU, target CU is target donor CU, and source CU is source donor CU.

[0169] In certain embodiments, at least one of the target DU and source DU is a logical DU.

[0170] In a particular embodiment, the target CU selects the beam to be transmitted during the UE's HO.

[0171] In a particular embodiment, the beam is selected based on at least one of the following: a value indicating that the beam has the best channel quality; that the beam is associated with a particular PCI; that the beam operates at a particular frequency and / or within a particular frequency range; that the beam is associated with a particular cell index; that the beam has the maximum reference signal received power, or reference signal received quality, or signal-to-interference noise ratio, or received signal strength indicator; that the beam is not assigned to another UE; and that the beam is assigned to a subset of UEs to which the UE belongs.

[0172] In a particular embodiment, before transmitting the above information to the source CU, the target CU receives a measurement report and / or at least one value associated with the measurement report from the source CU. The measurement report and / or at least one value is associated with at least one measurement performed by the UE for HO from a first cell to a second cell, and the beam is selected based on the measurement report and / or at least one value associated with said measurement report.

[0173] In certain embodiments, the measurement report and / or at least one value associated with the measurement report are received from the source CU in a handover request message associated with the UE. Information indicating the beam to be transmitted from the target DU is sent to the source CU in a handover response message.

[0174] In a particular embodiment, the target CU receives a recommended beam to be used by the target DU, along with a measurement report or at least one value associated with the measurement report.

[0175] In certain embodiments, the recommended beam is associated with and / or indicated by at least one of the following: beam identifier, TCI status identifier, TCI status setting, SSB identifier, and CSI-RS resource identifier.

[0176] In a particular embodiment, the target CU transmits to the target DU information indicating the beam transmitted from the target DU during the HO of the UE from the first cell to the second cell.

[0177] In a particular embodiment, the target CU receives from the target DU at least one of the following: information indicating a beam transmitted from the target DU during the HO of a UE from a first cell to a second cell, and at least one TA value for said beam.

[0178] While the computing devices described herein (e.g., UEs, network nodes, hosts) may include combinations of illustrated hardware components, other embodiments may include computing devices with different combinations of components. It should be understood that these computing devices may include any suitable combination of hardware and / or software required to perform the tasks, features, functions, and methods disclosed herein. The decisions, calculations, acquisitions, or similar operations described herein may be performed by processing circuits, which may process information by, for example, converting acquired information to other information, comparing acquired or converted information with information stored in the network node, and / or performing one or more operations based on the acquired or converted information, and making decisions as a result of the processing. Furthermore, while components are depicted as single boxes located within larger boxes or nested within multiple boxes, in practice, computing devices may include multiple different physical components that make up the illustrated single component, and functionality may be separated between distinct components. For example, a communication interface may be configured to include any of the components described herein, and the functionality of those components may be separated between the processing circuit and the communication interface. In other examples, computationally intensive functions of any of these components may be implemented in software or firmware, while computationally intensive functions may be implemented in hardware.

[0179] In some embodiments, some or all of the functionalities described herein may be provided by a processing circuit executing a set of instructions stored in memory, which may be a computer program product in the form of a non-temporary computer-readable storage medium. In alternative embodiments, some or all of the functionalities may be provided by the processing circuit, such as in a hardwired manner, without executing instructions stored in separate or discrete device-readable storage mediums. In any of these specific embodiments, the processing circuit can be configured to perform the functionalities described, whether or not it executes instructions stored in a non-temporary computer-readable storage medium. The benefits provided by such functionalities are not limited to the processing circuit alone or other components of the computing device, but are enjoyed by the computing device as a whole, and / or by the end user and the wireless network in general.

[0180] Examples <Examples from Group A> Example A1. A method using user equipment for determining an access beam during a random access channelless HO (handover) for mIAB (Mobile Integrated Access and Backhaul), wherein the method includes any of the steps, features, or functions of the user equipment described above, either alone or in combination with other steps, features, or functions described above.

[0181] Example A2. A method of a previous embodiment, further comprising one or more additional user device steps, features, or functions described above.

[0182] Example A3. A method according to any of the preceding embodiments, further comprising providing user data and transferring the user data to a host computer via transmission to a network node.

[0183] <Examples from Group B> Example B1. A method performed by a network node for determining an access beam during a random access channelless HO (handover) for mIAB (Mobile Integrated Access and Backhaul), wherein the method includes, alone or in combination with, any of the network node steps, features, or functions described above.

[0184] Example B2. A method of a previous embodiment, further comprising one or more additional network node steps, features, or functions described above.

[0185] Example B3. A method according to any of the preceding embodiments, further comprising acquiring user data and transferring the user data to a host or user device.

[0186] <Examples of Group C> Example C1. A method for mobile integrated access and backhaul (mIAB) using user equipment (UE), the method comprising receiving information indicating the beam to be used in a target DU (distributed unit) during the HO (handover) of the UE from a first cell to a second cell.

[0187] Example C2. A method according to Example C1, wherein the information is received from a source CU (aggregation unit) via a source DU.

[0188] Example C3. A method of Embodiment C2, wherein the source CU communicates with the source DU via a first F1 connection, and the target CU communicates with the target DU via a second F1 connection, at least one of these.

[0189] Example C4. A method according to Example C2 or C3, wherein the target DU and the source DU are associated with a mobile-IAB node.

[0190] Example C5. A method of any one of Examples C2 to C4, wherein the target DU is a target donor DU, the source DU is a source donor DU, the target CU is a target donor CU, and the source CU is a source donor CU.

[0191] Example C6. A method according to any one of Examples C2 to C5, wherein at least one of the target DU and the source DU is a logical DU.

[0192] Example C7. A method, one of the embodiments C1 to C6, wherein the information is received in an RRCReconfiguration message.

[0193] Example C8. A method comprising any one of Examples C1 to C7, wherein the HO includes an mIAB (Mobile-IAB) RACH-less (Random Access Channel-less) HO.

[0194] Example C9. A method, one of the examples C1 to C8, comprising sending a measurement report to the source CU before receiving the information.

[0195] Example C10. A method of Example C9, comprising: receiving a plurality of beams from the target DU; performing at least one measurement procedure based on each of the plurality of beams; and generating the measurement report.

[0196] Example C11. A method according to Example C10, wherein the measurement report is transmitted to the source CU based on the fulfillment of a condition or the detection of a trigger event.

[0197] Example C12. A method of Example C11, wherein the conditions are met and / or the trigger event is detected if a certain period of time has elapsed since a previous measurement report was sent, if the value indicating the channel intensity of the first cell falls below a threshold, if the mIAB migration requires that all UEs associated with the source CU be migrated to the target CU, if the mIAB migration requires that all UEs associated with the source DU be migrated to the target DU, and if the mIAB migration requires that all UEs associated with the first cell be migrated to the second cell.

[0198] Example C13. A method, any one of Examples C9 to C12, wherein the measurement report includes a plurality of values, each of which is associated with a measurement performed by the UE for each of the plurality of beams from the target DU.

[0199] Example C14. A method of Example C13, wherein the plurality of values ​​include at least one of the following: channel quality value, reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-interference noise ratio (SINR), and received signal strength indicator (RSSI).

[0200] Example C15. A method of Example C13 or C14, wherein at least one of the plurality of values ​​is identified as being associated with at least one of the following: PCI associated with a particular beam; a beam operating at a particular frequency and / or within a particular frequency range; a beam associated with a particular cell index; a beam not assigned to another UE; and a beam assigned to a subset of UEs to which the UE belongs.

[0201] Example C16. A method, any one of Examples C1 to C15, wherein the beam is associated with at least one of a beam identifier, a transmit setting indication (TCI) state identifier, a TCI state configuration, a synchronization signal block (SSB) identifier, and a channel state-information reference signal (CSI-RS) resource identifier, and / or the information identifies the beam by at least one of them.

[0202] Example C17. A method according to any one of Examples C1 to C16, comprising receiving, together with the information, at least one TA value for the beam used in the target DU during the HO of the UE from the first cell to the second cell.

[0203] Example C18. A method according to any one of Examples C1 to C17, comprising receiving an indication, along with the information, that the HO includes a RACH-less HO from the first cell to the second cell.

[0204] Example C19. A method, any one of the embodiments C1 to C18, further comprising providing user data and transferring the user data to a host via transmission to the network node.

[0205] Example C20. A user device comprising a processing circuit configured to perform any of the methods of Examples C1 to C19.

[0206] Example C21. A user device configured to perform any of the methods of Examples C1 to C19.

[0207] Example C22. A wireless device comprising a processing circuit configured to perform any of the methods of Examples C1 to C19.

[0208] Example C23. A computer program that includes instructions, wherein, when executed on a computer, the instructions execute one of the methods of Examples C1 to C19.

[0209] Example C24. A computer program product comprising a computer program, wherein the computer program, when executed on a computer, includes instructions that execute any of the methods of Examples C1 to C19.

[0210] Example C25. A non-temporary computer-readable medium storing instructions, wherein, when executed by a computer, the instructions execute one of the methods of Embodiments C1 to C19.

[0211] <Examples from Group D> Example D1. A method for mobile integrated access and backhaul (mIAB) using a source aggregation unit (CU), the method comprising transmitting to the user equipment (UE) information indicating the beam to be used in a target distribution unit (DU) during a handover (HO) of the user equipment (UE) from a first cell to a second cell.

[0212] Example D2. A method according to Embodiment D1, wherein the source CU communicates with the source DU via a first F1 connection, and / or the target CU communicates with the target DU via a second F1 connection.

[0213] Example D3. A method according to Example D2, wherein the target DU and the source DU are associated with a mobile-IAB node.

[0214] Example D4. A method of Example D2 or D3, wherein at least one of the following is true: the target DU is a target donor DU, the source DU is a source donor DU, the target CU is a target donor CU, and the source CU is a source donor CU.

[0215] Example D5. A method according to any one of the embodiments D1 to D4, wherein at least one of the target DU and the source DU is a logical DU.

[0216] Example D6. A method in any one of the embodiments D1 to D5, wherein the information is transmitted to the UE in an RRCReconfiguration message.

[0217] Example D7. A method of any one of Examples D1 to D6, wherein the HO includes a mobile-IAB (mIAB) random access channelless (RACH-less) HO, and / or the method includes determining that an mIAB RACH-less handover should be triggered toward a target CU.

[0218] Example D8. A method of any one of the embodiments D1 to D7, comprising receiving a measurement report associated with the UE before transmitting the information to the UE, wherein the measurement report includes a plurality of values, each of which is associated with a measurement performed by the UE for one of a plurality of beams emitted by the target DU, and / or the measurement report is received via the source DU via an F1 connection.

[0219] Example D9. A method of Example D8, comprising selecting the beam to be used in the target DU during the HO of the UE from the first cell to the second cell, based on the measurement report including the plurality of values.

[0220] Example D10. A method of Embodiment D9, wherein the beam is selected to be used on the basis of at least one of the following: a value indicating that the beam has the best channel quality; the beam is associated with a particular PCI; the beam operates at a particular frequency and / or within a particular frequency range; the beam is associated with a particular cell index; the beam has the highest reference signal received power (RSRP) or reference signal received quality (RSRQ) or signal-to-interference noise ratio (SINR) or received signal strength indicator (RSSI); the beam is not assigned to another UE; and the beam is assigned to a subset of UEs to which the UE belongs.

[0221] Example D11. A method according to Example D9 or D10, wherein the beam is associated with at least one of a beam identifier, a transmit setting indication (TCI) status identifier, a TCI status setting, a synchronization signal block (SSB) identifier, and a channel status information reference signal (CSI-RS) resource identifier, and / or the information identifies the beam by at least one of these.

[0222] Example D12. A method of Example D9, comprising transmitting the information indicating the beam to be used in the target DU to the target CU during the HO of the UE from the first cell to the second cell.

[0223] Example D13. A method according to Example D12, wherein the information is transmitted in a handover request message associated with the UE.

[0224] Example D14. A method of Embodiment D13, wherein the information is transmitted in a handover request message associated with a plurality of UEs, and the information indicates that the beam is used in the target DU during the HO of the plurality of UEs from the first cell to the second cell, or that at least one additional beam is used in the target DU during the HO of at least one additional UE from the first cell to the second cell.

[0225] Example D15. A method comprising any one of the embodiments D12 to D14, wherein the information is transmitted to the target CU via the Xn interface or the NG interface.

[0226] Example D16. A method according to any one of Examples D12 to D15, comprising receiving a response message from the target CU, wherein the response message comprises at least one of a handover response message, a handover request acknowledgment response message, a handover command message, and an RRC reset message; the response message comprises the information indicating the beam used in the target DU during the HO of the UE from the first cell to the second cell; and the response message comprises at least one TA value for the beam used in the target DU during the HO of the UE from the first cell to the second cell.

[0227] Example D17. A method of embodiment D16, wherein at least one TA value for the beam is transmitted to the UE, along with the information indicating the beam used in the target DU during the HO of the UE from the first cell to the second cell.

[0228] Example D18. A method of Example D8, comprising: transmitting the measurement report or at least one value associated with the measurement report to a target CU associated with the target DU; and receiving the information from the target CU indicating the beam used in the target DU during the HO of the UE from the first cell to the second cell.

[0229] Example D19. A method of Example D18, wherein transmitting the measurement report or at least one value associated with the measurement report comprises transmitting at least one of the following: all values ​​associated with the measurement report, at least one value associated with and / or related to the target CU, at least one value associated with and / or related to a second cell associated with the target CU, at least one value associated with and / or related to all cells associated with the target DU, at least one value associated with and / or related to at least one cell associated with the target DU, and / or at least one value associated with and / or related to the second cell.

[0230] Example D20. A method of Example D18 or D19, comprising transmitting a recommended beam to be used with the target DU, along with the measurement report or at least one value associated with the measurement report.

[0231] Example D21. A method of Example D20, wherein the recommended beam is selected by the source CU based on at least one of the following: a value indicating that the beam has the best channel quality; that the beam is associated with a particular PCI; that the beam operates at a particular frequency and / or within a particular frequency range; that the beam is associated with a particular cell index; that the beam has the highest reference signal received power (RSRP) or reference signal received quality (RSRQ) or signal-to-interference noise ratio (SINR) or received signal intensity indicator (RSSI); that the beam is not assigned to another UE; and / or that the beam is assigned to a subset of UEs to which the UE belongs.

[0232] Example D22. A method of Example D20 or D21, wherein the recommended beam is associated with at least one of a beam identifier, a transmit setting indication (TCI) status identifier, a TCI status setting, a synchronization signal block (SSB) identifier, and a channel status information reference signal (CSI-RS) resource identifier, and / or the recommended beam is indicated by at least one of these.

[0233] Example D23. A method, one of the embodiments D18 to D22, wherein the measurement report or at least one value associated with the measurement report is sent to the target CU in or together with the handover request message.

[0234] Example D24. A method of Example D23, wherein the handover request message is associated with a plurality of UEs (including the UE), and the handover request message comprises at least one of a plurality of measurement reports, each measurement report associated with a relevant one of the plurality of UEs; a plurality of measurements, each measurement associated with a relevant one of the plurality of UEs; a recommended beam to be used in the target DU during the HO of the plurality of UEs from the first cell to the second cell; and a plurality of recommended beams to be used in the target DU during the HO of the plurality of UEs from the first cell to the second cell, each recommended beam associated with a relevant one of the plurality of UEs.

[0235] Example D25. A method according to any of Examples D18 to D24, wherein the measurement report or at least one value associated with the measurement report is transmitted to the target CU via the Xn interface or the NG interface.

[0236] Example D26. A method according to any one of Examples D18 to D25, wherein the information indicating the beam used in the target DU is received from the target CU in a response message, the response message includes at least one of a handover response message, a handover request acknowledgment response message, a handover command message, and an RRC reset message, and the response message includes at least one TA value for the beam used in the target DU during the HO of the UE from the first cell to the second cell.

[0237] Example D27. A method of embodiment D26, wherein at least one TA value for the beam is transmitted to the UE, along with the information indicating the beam used in the target DU during the HO of the UE from the first cell to the second cell.

[0238] Example D28. A method of Example D26 or 27, wherein the response message indicates that a beam is used at the target DU during the HO of a plurality of UEs (including the UE) from the first cell to the second cell, and that at least one additional beam is used at the target DU during the HO of at least one additional UE from the first cell to the second cell.

[0239] Example D29. A method according to any of the examples D1 to D28, further comprising acquiring user data and transferring the user data to a host or user device.

[0240] Example D30. A network node comprising a processing circuit configured to perform any of the methods of Examples D1 to D29.

[0241] Example D31. A network node configured to perform any of the methods of Examples D1 to D29.

[0242] Example D32. A computer program comprising instructions that, when executed by a computer, perform any of the methods of Examples D1 to D29.

[0243] Example D33. A computer program product comprising a computer program, wherein the computer program comprises instructions that, when executed by a computer, perform any of the methods of Examples D1 to D29.

[0244] Example D34. A non-transitory computer-readable medium storing instructions that, when executed by a computer, perform any of the methods of Examples D1 to D29.

[0245] <Examples of Group E> Example E1. A method for indicating at least one access beam for mobile integrated access and backhaul (mIAB) by a target centralized unit (CU), the method comprising at least one of: receiving information indicating a beam to be used by a target distributed unit (DU) from a source CU during handover (HO) of a user equipment (UE) from a first cell to a second cell, and / or transmitting said information to the source CU.

[0246] Example E2. The method of Example E1, wherein at least one of: the source CU communicates with a source DU via a first F1 connection, and the target CU communicates with the target DU via a second F1 connection.

[0247] Example E3. A method of Example E2, wherein the target DU and the source DU are associated with a mobile IAB node.

[0248] Example E4. A method of Example E2 or E3, wherein the target DU is a target donor DU, the source DU is a source donor DU, the target CU is a target donor CU, and the source CU is a source donor CU.

[0249] Example E5. A method according to any of Examples E1 to E4, wherein at least one of the target DU and the source DU is a logical DU.

[0250] Example E6. A method of any of Examples E1 to E5, wherein the HO includes a mobile IAB (mIAB) random access channelless (RACH-less) HO.

[0251] Example E7. A method in any of Examples E1 to E6, wherein the information indicating the beam used in the target DU is transmitted from the target CU to the source CU.

[0252] Example E8. A method of Example E7, comprising: receiving a measurement report and / or at least one value associated with the measurement report from the source CU before transmitting the information to the source CU, wherein the measurement report and / or the at least one value is associated with the UE for the HO from the first cell to the second cell; and selecting the beam to be used in the target DU during the HO of the UE from the first cell to the second cell based on the measurement report and / or the at least one value associated with the measurement report.

[0253] Example E9. A method of Example E8, wherein the measurement report includes a plurality of values, each of which is associated with a measurement performed by the UE for one of a plurality of beams emitted by the target DU, and / or the measurement report is received via an Xn or NG connection.

[0254] Example E10. A method of Example E8 or E9, wherein the beam is selected by the target CU to be used in the HO of the UE, the selection being based on at least one of the following: a value indicating that the beam has the best channel quality; the beam is associated with a particular PCI; the beam operates at a particular frequency and / or within a particular frequency range; the beam is associated with a particular cell index; the beam has the highest reference signal received power (RSRP) or reference signal received quality (RSRQ) or signal-to-interference noise ratio (SINR) or received signal intensity indicator (RSSI); the beam is not assigned to another UE; and the beam is assigned to a subset of UEs to which the UE belongs.

[0255] Example E11. A method according to any of Examples E8 to E10, wherein the measurement report and / or at least one value associated with the measurement report is received from the source CU in a handover request message associated with the UE.

[0256] Example E12. The method according to any one of Embodiments E8 to E10, wherein the measurement report and / or at least one value associated with the measurement report is received from the source CU in a handover request message associated with a plurality of UEs, and the information transmitted to the source CU indicates that the beam is to be used by the target DU during the HO of the plurality of UEs from the first cell to the second cell, or at least one additional beam is to be used by the target DU during the HO of at least one additional UE from the first cell to the second cell.

[0257] Embodiment E13. The method according to any one of Embodiments E8 to E12, comprising receiving a recommended beam to be used by the target DU together with the measurement report or the at least one value associated with the measurement report.

[0258] Embodiment E14. The method according to Embodiment E13, wherein the recommended beam is associated with at least one of a beam identifier, a transmission configuration indication (TCI) state identifier, a TCI state configuration, a synchronization signal block (SSB) identifier, and a channel state information reference signal (CSI-RS) resource identifier, and / or the recommended beam is indicated by at least one of the foregoing.

[0259] Embodiment E15. The method according to any one of Embodiments E7 to E14, wherein the beam is associated with at least one of a beam identifier, a transmission configuration indication (TCI) state identifier, a TCI state configuration, a synchronization signal block (SSB) identifier, and a channel state information reference signal (CSI-RS) resource identifier, and / or the information transmitted to the source CU identifies the beam by at least one of the foregoing.

[0260] Embodiment E16. A method according to any of Examples E7 to E15, wherein the information indicating the beam used in the target DU is transmitted to the source CU in a response message, the response message comprising at least one of a handover response message, a handover request confirmation message, a handover command message, and an RRC reconfiguration message.

[0261] Example E17. A method of Example E16, wherein the response message is transmitted to the UE from the first cell to the second cell, along with information indicating the beam used in the target DU, and at least one TA value for the beam.

[0262] Example E18. A method in any of Examples E1 to E6, wherein the information indicating the beam used in the target DU is received from the source CU.

[0263] Example E19. A method of Example E18, wherein the information indicating the beam includes at least one of a beam identifier, a Transmit Setting Indication (TCI) status identifier, a TCI status setting, a Synchronization Signal Block (SSB) identifier, and a Channel Status Information Reference Signal (CSI-RS) resource identifier.

[0264] Example E20. A method according to Example E18 or E19, wherein the information indicating the beam used in the target DU is received by the target CU in or together with the handover request message associated with the UE.

[0265] Example E21. A method of Example E18 or E19, wherein the information is transmitted in a handover request message associated with a plurality of UEs (including the UE), and the information indicates that the beam is used in the target DU during the HO of the plurality of UEs from the first cell to the second cell, or that at least one additional beam is used in the target DU during the HO of at least one additional UE from the first cell to the second cell.

[0266] Example E22. A method according to any of Examples E18 to E21, wherein the information is received from the source CU via the Xn interface or the NG interface.

[0267] Example E23. A method according to any of Examples E17 to E22, comprising sending a response message from the target CU, wherein the response message includes at least one of a handover response message, a handover request acknowledgment response message, a handover command message, and an RRC reset message; the response message includes the information indicating the beam used in the target DU during the HO of the UE from the first cell to the second cell; and the response message includes at least one TA value for the beam used in the target DU during the HO of the UE from the first cell to the second cell.

[0268] Example E24. A method according to any of Examples E1 to E23, comprising transmitting to the target DU the information indicating the beam used in the target DU during the HO of the UE from the first cell to the second cell.

[0269] Example E25. A method of Example E24, wherein the information indicating the beam used in the target DU is transmitted to the target DU together with, or in, a request to establish a UE context for the UE.

[0270] Example E26. A method of Example E24 or E25, comprising receiving from the target DU at least one of the following: a lower layer setting used in the HO of the UE from the first cell to the second cell; the information indicating the beam used in the target DU in the HO of the UE from the first cell to the second cell; and at least one TA value for the beam.

[0271] Example E27. A method according to any of Examples E1 to E26, further comprising acquiring user data and transferring the user data to a host or user device.

[0272] Example E28. A network node comprising a processing circuit configured to perform any of the methods of Examples E1 to E27.

[0273] Example E29. A network node configured to perform any of the methods of Examples E1 to E27.

[0274] Example E30. A computer program that, when executed by a computer, includes instructions that perform any of the methods of Examples E1 to E27.

[0275] Example E31. A computer program product comprising a computer program, wherein the computer program, when executed on a computer, includes instructions that perform any of the methods of Examples E1 to E27.

[0276] Example E32. A non-temporary computer-readable medium containing instructions that, when executed by a computer, perform one of the methods of Examples E1 to E27.

[0277] <Examples of Group F> Example F1. A user device (UE) for mobile integrated access and backhaul (mIAB), the UE comprising: a processing circuit configured to perform any of the steps included in any of the embodiments of Groups A and C; and a power supply circuit configured to supply power to the processing circuit.

[0278] Example F2. A network node for indicating access beams for mobile integrated access and backhaul (mIAB), the network node comprising: a processing circuit configured to perform any of the steps included in any of the embodiments of groups B, D, and E; and a power supply circuit configured to supply power to the processing circuit.

[0279] Example F3. A user device (UE) for mobile integrated access and backhaul (mIAB), the UE comprising: an antenna configured to transmit and receive radio signals; a radio front-end circuit connected to the antenna and a processing circuit and configured to adjust signals communicated between the antenna and the processing circuit; the processing circuit configured to perform any of the steps included in any of the embodiments of Groups A and C; an input interface connected to the processing circuit and configured to allow input to the UE of information to be processed by the processing circuit; an output interface connected to the processing circuit and configured to output from the UE the information processed by the processing circuit; and a battery connected to the processing circuit and configured to supply power to the UE.

Claims

1. A method (1300) by a UE (User Equipment) (102) for mIAB (Mobile Integrated Access and Backhaul), wherein the method is A method comprising receiving information (1302) indicating a beam to be transmitted from a target DU (distributed unit) (104) during the HO of the UE from a first cell to a second cell, wherein the HO includes an mIAB RACH-less (random access channel-less) HO.

2. A method according to claim 1, wherein the beam is Beam identifier and, Sending setting indication status identifier, TCI status setting, Synchronization signal block identifier, Channel status information - reference signal resource identifier, It is associated with at least one of the following, and / or A method for identifying the beam by at least one of the aforementioned pieces of information.

3. A method according to claim 1 or 2, comprising receiving, together with the information, at least one TA value for the beam to be transmitted from the target DU during the HO of the UE from the first cell to the second cell.

4. A method according to any one of claims 1 to 3, wherein the information is received from a source CU (aggregation unit) (108) via a source DU (110).

5. The method according to claim 4, The aforementioned target DU (104) is a target donor DU. The source DU (110) is a source donor DU. The target CU (112) is the target donor CU, and The source CU (108) is a source donor CU. A method that is at least one of the following.

6. A method according to any one of claims 1 to 5, wherein at least one of the target DU and the source DU is a logical DU.

7. A method according to any one of claims 1 to 6, wherein the method, before receiving the information, Receiving multiple beams from the target DU, Performing at least one measurement procedure based on each of the plurality of beams, and Sending a measurement report to the source CU, which includes at least one value associated with at least one measurement performed by the UE for at least one of the plurality of beams in the target DU, Methods that include...

8. A method (1400) for mIAB (Mobile Integrated Access and Backhaul) using a source CU (aggregation unit) (108), wherein the method is: A method comprising transmitting to a UE (User Equipment) (102) information indicating a beam to be transmitted from a target DU (Distributed Unit) (104) during a HO (Handover) of the UE (User Equipment) (102) from a first cell to a second cell (1402), wherein the HO includes an mIAB RACH-less (Random Access Channel-less) HO.

9. The method according to claim 8, wherein the beam is Beam identifier and, Sending setting indication status identifier, TCI status setting, Synchronization signal block identifier, Channel status information - reference signal resource identifier, It is associated with at least one of the following, and / or A method for identifying the beam by at least one of the aforementioned pieces of information.

10. A method according to claim 8 or 9, wherein at least one TA value for the beam is transmitted to the UE along with the information indicating the beam to be transmitted by the target DU during the HO of the UE from the first cell to the second cell.

11. A method according to any one of claims 8 to 10, wherein the information is transmitted to the UE via a source DU.

12. The method according to claim 11, The aforementioned target DU (104) is a target donor DU. The source DU (110) is a source donor DU. The target CU (112) is the target donor CU, and The source CU (108) is a source donor CU. A method that is at least one of the following.

13. A method according to claim 11 or 12, wherein at least one of the target DU and the source DU is a logical DU.

14. A method according to any one of claims 8 to 13, A method comprising determining that the aforementioned mIAB RACHless handover should be triggered toward a target CU.

15. A method according to any one of claims 8 to 14, The process includes receiving a measurement report associated with the UE before transmitting the aforementioned information to the UE, A method wherein the measurement report includes at least one value associated with at least one measurement performed by the UE for at least one beam transmitted by the target DU.

16. The method according to claim 15, Sending the measurement report, or at least one value associated with the measurement report, to the target CU associated with the target DU, and Receiving from the target CU the information indicating the beam to be transmitted from the target DU during the HO of the UE from the first cell to the second cell, Methods that include...

17. A method according to claim 16, comprising transmitting a recommended beam to be transmitted from the target DU together with the measurement report, or the at least one value associated with the measurement report.

18. The method according to claim 17, wherein the recommended beam is The value indicating that the recommended beam has the best channel quality, The recommended beam is associated with a specific PCI. The recommended beam operates at a specific frequency and / or within a specific frequency range. The recommended beam is associated with a specific cell index. The recommended beam has the strongest reference signal received power, reference signal received quality, signal-to-interference noise ratio, and / or received signal strength indicator. The aforementioned recommended beam is not assigned to any other UE, and The recommended beam is assigned to a subset of UEs to which the UE belongs. A method selected by the source CU based on at least one of the following.

19. The method according to claim 17 or 18, wherein the recommended beam is Beam identifier and, Sending setting indication status identifier, TCI status setting, Synchronization signal block identifier, Channel status information - reference signal resource identifier, It is associated with at least one of the following, and / or The aforementioned recommended beams are indicated by at least one of them, by a method.

20. A method according to any one of claims 16 to 19, The measurement report, or the at least one value associated with the measurement report, is transmitted to the target CU in a handover request message, or together with the handover request message. The method includes receiving a handover response message from the target CU, which includes the information indicating the beam to be transmitted from the target DU.

21. A method according to claim 20, wherein the response message includes at least one TA value for the beam to be transmitted from the target DU during the HO of the UE from the first cell to the second cell.

22. A method (1500) using a target CU (aggregation unit) (112) for mIAB (Mobile Integrated Access and Backhaul), A method comprising receiving from and / or transmitting to a source CU (108) information indicating a beam to be transmitted by a target DU (distributed unit) (104) during a HO (handover) of a UE (user equipment) (102) from a first cell to a second cell, wherein the HO includes an mIAB RACH-less (random access channel-less) HO.

23. A method according to claim 22, wherein the beam is Beam identifier and, Sending setting indication status identifier, TCI status setting, Synchronization signal block identifier, Channel status information - reference signal resource identifier, It is associated with at least one of the following, and / or A method for identifying the beam by at least one of the aforementioned pieces of information.

24. A method according to claim 22 or 23, wherein at least one TA value for the beam is transmitted to the UE, along with the information indicating the beam to be transmitted by the target DU during the HO of the UE from the first cell to the second cell.

25. A method according to any one of claims 22 to 24, The aforementioned target DU (104) is a target donor DU. Source DU (110) is the source donor DU. The aforementioned target CU (112) is a target donor CU, and The source CU (108) is a source donor CU. A method that is at least one of the following.

26. A method according to claim 25, wherein at least one of the target DU and the source DU is a logical DU.

27. A method according to any one of claims 22 to 26, comprising selecting the beam to be transmitted in the HO of the UE.

28. A method according to claim 27, wherein the beam is A value indicating that the beam has the best channel quality, The beam is associated with a specific PCI. The beam operates at a specific frequency and / or within a specific frequency range. The beam is associated with a specific cell index, The beam has the strongest reference signal received power, or reference signal received quality, or signal-to-interference noise ratio, or received signal strength indicator. The aforementioned beam is not allocated to any other UE, and The beam is assigned to a subset of UEs to which the UE belongs. A method selected based on at least one of the following.

29. The method according to claim 27 or 28, Before transmitting the information to the source CU, the method includes receiving a measurement report and / or at least one value associated with the measurement report from the source CU, wherein the measurement report and / or the at least one value is associated with at least one measurement performed by the UE for HO from the first cell to the second cell, A method by which the beam is selected based on the measurement report and / or the at least one value associated with the measurement report.

30. The method according to claim 29, The measurement report and / or the at least one value associated with the measurement report is received from the source CU in a handover request message associated with the UE. The information indicating the beam to be transmitted from the target DU is transmitted to the source CU in a handover response message.

31. A method according to claim 29 or 30, comprising receiving the measurement report, or the at least one value associated with the measurement report, along with a recommended beam to be used in the target DU.

32. The method according to claim 31, wherein the recommended beam is Sending setting indication status identifier, TCI status setting, Synchronization signal block identifier, Channel status information - reference signal resource identifier, It is associated with at least one of the following, and / or The aforementioned recommended beams are indicated by at least one of them, by a method.

33. A method according to any one of claims 22 to 32, comprising transmitting to the target DU the information indicating the beam to be transmitted from the target DU during the HO of the UE from the first cell to the second cell.

34. A method according to any one of claims 22 to 32, wherein the target DU is The information indicating the beam to be transmitted from the target DU during the HO of the UE from the first cell to the second cell, and At least one TA value for the beam, A method that includes receiving at least one of the following.

35. A UE (User Equipment) (102) for mIAB (Mobile Integrated Access and Backhaul), wherein the UE is The UE is configured to receive information indicating a beam to be transmitted from a target DU (distributed unit) (104) during the HO (handover) of the UE from a first cell to a second cell, wherein the HO includes an mIAB RACH-less (random access channel-less) HO.

36. A UE according to claim 35, wherein the UE is configured to perform the method described in any one of claims 2 to 8.

37. A source CU (aggregation unit) (108) for mIAB (Mobile Integrated Access and Backhaul), wherein the source CU is The system is configured to transmit to the UE information indicating a beam to be transmitted from the target DU (distributed unit) (104) during the HO (handover) of the UE (user equipment) (102) from the first cell to the second cell, wherein the HO includes a source CU, and the HO includes an mIAB RACHless (random access channelless) HO.

38. A source CU according to claim 37, wherein the source CU is configured to perform the method described in any one of claims 10 to 22.

39. A target CU (aggregation unit) (112) for mIAB (Mobile Integrated Access and Backhaul), The system is configured to receive from and / or transmit to a source CU (108) information indicating a beam to be transmitted by a target DU (distributed unit) (104) during a HO (handover) of a UE (user equipment) (102) from a first cell to a second cell, wherein the HO includes an mIAB RACH-less (random access channel-less) HO.

40. A target CU according to claim 39, wherein the target CU is configured to perform the method described in any one of claims 24 to 35.

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