Systems and methods for indicating an access beam to a user equipment during a rach-less handover for mobile integrated access and backhaul

Abstract

A method (1300) by a user equipment, UE (102), for mobile-integrated Access and Backhaul, mlAB, includes receiving (1302) information indicating a beam to be transmitted from a target Distributed Unit (104), DU, during a HO of the UE from a first cell to a second cell. The HO comprises a mlAB Random Access Channel-less, RACH-less, HO.

Description

[0001] SYSTEMS AND METHODS FOR INDICATING AN ACCESS BEAM TO A USER EQUIPMENT DURING A RACH-LESS HANDOVER FOR MOBILE INTEGRATED ACCESS AND BACKHAUL

[0002] TECHNICAL FIELD

[0003] The present disclosure relates, in general, to wireless communications and, more particularly, systems and methods for indicating an access beam to a User Equipment (UE) during a RACH-less handover for mobile integrated access and backhaul (mlAB).

[0004] BACKGROUND

[0005] In Release 18, it is expected that the different Random Access Network (RAN) groups will work towards enhancing functionality of Integrated Access and Backhaul (IAB) through mobile- IAB (mlAB) providing 5thGeneration (5G) coverage enhancement to onboard and surrounding User Equipments (UEs). The initial use cases for mobile-IAB / vehicle mounted relay (VMR) are expected to be based on 3GPP TR 22.839 V.18. 1.0.

[0006] One of the main use cases of mlAB cell is to serve the UEs that are residing in the vehicle with the VMR. Other relevant use cases for mobile lABs involves a mobile / nomadic IAB network node, which is mounted on a vehicle and provides extended coverage. This involves scenarios where additional coverage is required during special events like concerts or during disasters. The nomadic IAB node provides access to surrounding UEs, while the backhaul traffic from the nomadic IAB node is transmitted wirelessly either with the help of IAB donors or non-terrestrial networks (NTN). A nomadic IAB node also reduces or even eliminates signal strength loss due to vehicle penetration for UEs that are present in the vehicles.

[0007] Advantages of mlAB include reducing / eliminating the vehicle penetration loss (specially at high frequency) and / or reducing / eliminating group handover.

[0008] In most use cases, the mlAB is expected to be mounted on public transport vehicles. To a large extent, the mlAB are expected to move in a pre -determined route. FIGURE 1 illustrates one such mlAB mounted on a bus travelling on a route that is covered by four different parent IAB nodes, which are depicted as parent 1, parent 2, parent 3, and parent 4). The parent nodes backhaul their traffic through two donor nodes, which are depicted as donor X and donor Y. An IAB node has an IAB -Distributed Unit (IAB-DU) that provides access to UEs around it. The IAB node also has an lAB-Mobile Termination (IAB-MT) that provides a backhaul connection from the IAB node to its parent(s) and the rest of the network. The parent IAB nodes consist of lAB-Dus that provide access to UEs and the mlAB present in the coverage area of a respective IAB-DU. lAB-nodes also consist of an IAB-MT, which backhauls its traffic together with traffic from the mlAB node. Finally, the two donor nodes consist of Distributed Unit (DU) that provides access and Centralized Unit (CU) that is connected to the core network. The CUs in both donor nodes maintain a Fl connection to lAB-Dus under it.

[0009] When the mlAB node moves from one geographical area to the next, it passes through different areas covered by various cells of stationary parent nodes.

[0010] FIGURE 2 illustrates a UE handover (HO) between cells pertaining to different logical lAB-DUs connect to separate CUs. In general, 3rdGeneration Partnership Project (3GPP) assumes that the mlAB-DU migration between different donor-CUs will be realized by providing a second logical mlAB-DU in an mlAB node (IAB-DU2), which will establish Fl connection to the target donor CU for mlAB-DU migration (IAB-donor-CU2). Then, the UEs served by the mlAB-node will be handed over from a cell of mlAB-DUl controlled by source donor CU (CUI) to a cell of mIAB-DU2 controlled by target donor CU (CU2). The two cells reside on the same physical IAB- node but they each have a separate Fl connection to lAB-donor-CU 1 and IAB-donor-CU2, respectively, as shown in FIGURE 2. After UEs are handed over between the mlAB-DUl and mIAB-DU2, the first connection between the mlAB-DUl and lAB-donor-CUl is released.

[0011] A HO that is executed without performing a RACH procedure may be called a RACH-less HO. Some 3GPP RAN2 agreements for RACH-less HO in mobile IAB include:

[0012] RAN2#121bis meeting agreements:

[0013] • Feasibility of beam handling during RACH-less HO in the mlAB WI is [for Future Study (FFS)] (and this need to be addressed for RACH-less to be supported for mlAB).

[0014] • RAN2 discuss further the following options to support beam operation for the first uplink (UL) transmission / downlink (DL) reception towards the target logical DU in Random Access Channel-less (RACH-less) HO during DU migration:

[0015] Option 1 : (Explicit approach) Explicit beam information is included in HO command. FFS the details. • Option 2: (Implicit approach) UE re-uses the same beam status as in the source cell (the beam information is not carried explicitly in HO command).

[0016] • RACH-less HO with same Timing Advance (TA) with security key change is in scope for served UEs during mlAB DU migration. FFS UL grant and HO completion procedure in mlAB RACH-less HO.

[0017] RAN2#122 meeting agreements:

[0018] • RAN2 think that to have a fast handover from UE point of view for legacy UEs it is important that the target cell is known to the UE (detected and measured).

[0019] • For RACH-less, if supported, there would need to be a beam indication (in RRC HO command), which seems feasible in this release from R2 perspective. R2 assumes that the network can know / select the beam, either from network impl specific knowledge or from UE measurement report (legacy report).

[0020] • for the UL grant and HO completion in RACH-less HO:

[0021] 1. Both type-1 configured grant and dynamic grant are supported

[0022] 2. FFS handling of supervision timer and when HO is considered successfully complete (expect to align with other WI).

[0023] • Send LS to RAN3 to check whether there are issues / feasibility concerns.

[0024] There currently exist certain challenge(s), however. For example, according to the discussions taken in 3GPP RAN2 Working Group, a RACH-less handover for UEs served by a mobile IAB node will be supported in Release 18. However, one open issue is how to indicate to the UE which beam the UE should use when switching to a second logical mlAB-DU. This is also related to the following agreement:

[0025] For RACH-less, if supported, there would need to be a beam indication (in RRC HO command), which seems feasible in this release from R2 perspective. R2 assumes that the network can know / select the beam, either from network impl specific knowledge or from UE measurement report (legacy report).

[0026] According to previous (i.e., Layer 3 (L3)) HO techniques, it is the UE that usually determines, during the RACH procedure, the beam to use in the target cell. However, in the case where there is no RACH procedure involved, it would be not possible for the UE to determine which beam to use in the target (second) logical mlAB-DU.

[0027] SUMMARY

[0028] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. For example, according to certain embodiments, methods and systems are provided that enable the UE to receive information about the beam to be used in a target (second) logical DU during a RACH-less HO.

[0029] According to certain embodiments, a method by a UE for mlAB includes receiving information indicating a beam to be transmitted from a target DU during a HO of the UE from a first cell to a second cell. The HO comprises a mlAB RACH-less HO.

[0030] According to certain embodiments, a UE for mlAB is configured to receive information indicating a beam to be transmitted from a target DU during a HO of the UE from a first cell to a second cell. The HO comprises a mlAB RACH-less HO.

[0031] According to certain embodiments, a method by a source CU for mlAB includes transmitting, to a UE, information indicating a beam to be transmitted from a target DU during a HO of the UE from a first cell to a second cell. The HO comprises a mlAB RACH-less HO.

[0032] According to certain embodiments, a source CU for mlAB is configured to transmit, to a UE, information indicating a beam to be transmitted from a target DU during a HO of the UE from a first cell to a second cell. The HO comprises a mlAB RACH-less HO.

[0033] According to certain embodiments, a method by a target CU, for mlAB includes receiving from a source CU and / or transmitting to the source CU information indicating a beam to be transmitted from a target DU during a HO of a UE from a first cell to a second cell. The HO comprises an mlAB RACH-less HO.

[0034] According to certain embodiments, a target CU for mlAB is configured to receive from a source CU and / or transmitting to the source CU information indicating a beam to be transmitted from a target DU during a HO of a UE from a first cell to a second cell. The HO comprises an mlAB RACH-less HO.

[0035] Certain embodiments may provide one or more of the following technical advantage (s). For example, certain embodiments may provide a technical advantage of enabling the network to determine a proper beam to be used by the UE during a mobile IAB RACH-less handover (because of a DU migration). As another example, certain embodiments may provide a technical advantage of allowing the UE to complete the mobile IAB RACH-less handover procedure without handover failures and avoid long connectivity interruption. Other advantages may be readily apparent to one having skill in the art. Certain embodiments may have none, some, or all of the recited advantages.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] For a more complete understanding of the disclosed embodiments and their features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

[0038] FIGURE 1 illustrates an mlAB mounted on a bus travelling on a route that is covered by four different parent IAB nodes;

[0039] FIGURE 2 illustrates a UE HO between cells pertaining to different logical lAB-DUs connect to separate CUs;

[0040] FIGURE 3 illustrates an example method and signaling diagram for a network to determine and inform a UE about which beam the UE would need to use towards the second logical mlAB- DU, according to certain embodiments;

[0041] FIGURE 4 illustrates an example flow and signaling diagram that includes a source donor CU calculating and / or determining a beam to be used by a UE during a mlAB RACH-less HO, according to certain embodiments;

[0042] FIGURE 5 illustrates an example flow and signaling diagram that includes a target donor CU calculating and / or determining a beam to be used by a UE during a mlAB RACH-less HO, according to certain embodiments;

[0043] FIGURE 6 illustrates an example communication system, according to certain embodiments;

[0044] FIGURE 7 illustrates an example UE, according to certain embodiments;

[0045] FIGURE 8 illustrates an example network node, according to certain embodiments;

[0046] FIGURE 9 illustrates a virtualization environment in which functions implemented by some embodiments may be virtualized, according to certain embodiments;

[0047] FIGURE 10 illustrates an example method by a UE for mlAB, according to certain embodiments;

[0048] FIGURE 11 illustrates an example method by a CU for indicating at least one access beam for mlAB, according to certain embodiments;

[0049] FIGURE 12 illustrates an example method by a target CU for indicating at least one access beam for mlAB, according to certain embodiments;

[0050] FIGURE 13 illustrates an example method by a UE, for mlAB, according to certain embodiments; FIGURE 14 illustrates an example method 1200 by a source CU for mlAB, according to certain embodiments; and

[0051] FIGURE 15 illustrates a method by a target CU for mlAB, according to certain embodiments.

[0052] DETAIEED DESCRIPTION

[0053] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0054] As used herein, ‘node’ can be a network node or a UE. Examples of network nodes are NodeB, base station (BS), multi-standard radio (MSR) radio node such as MSR BS, eNodeB (eNB), gNodeB (gNB), Master eNB (MeNB), Secondary eNB (SeNB), integrated access backhaul (IAB) node, network controller, radio network controller (RNC), base station controller (BSC), relay, donor node controlling relay, base transceiver station (BTS), Central Unit (e.g. in a gNB), Distributed Unit (e.g. in a gNB), Baseband Unit, Centralized Baseband, C-RAN, access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU), Remote Radio Head (RRH), nodes in distributed antenna system (DAS), core network node (e.g. Mobile Switching Center (MSC), Mobility Management Entity (MME), etc.), Operations & Maintenance (O&M), Operations Support System (OSS), Self Organizing Network (SON), positioning node (e.g. E- SMLC), etc.

[0055] Another example of a node is user equipment (UE), which is a non-limiting term and refers to any type of wireless device communicating with a network node and / or with another UE in a cellular or mobile communication system. Examples of UE are target device, device to device (D2D) UE, vehicular to vehicular (V2V), machine type UE, MTC UE or UE capable of machine to machine (M2M) communication, Personal Digital Assistant (PDA), Tablet, mobile terminals, smart phone, laptop embedded equipment (LEE), laptop mounted equipment (LME), Unified Serial Bus (USB) dongles, etc.

[0056] In some embodiments, generic terminology, “radio network node” or simply “network node (NW node)”, is used. It can be any kind of network node which may comprise base station, radio base station, base transceiver station, base station controller, network controller, evolved Node B (eNB), Node B, gNodeB (gNB), relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH), Central Unit (e.g. in a gNB), Distributed Unit (e.g. in a gNB), Baseband Unit, Centralized Baseband, C-RAN, access point (AP), etc. The term radio access technology (RAT), may refer to any RAT such as, for example, Universal Terrestrial Radio Access Network (UTRA), Evolved Universal Terrestrial Radio Access Network (E-UTRA), narrow band internet of things (NB-IoT), WiFi, Bluetooth, next generation RAT, NR, 4G, 5G, etc. Any of the equipment denoted by the terms node, network node or radio network node may be capable of supporting a single or multiple RATs.

[0057] The term signal or radio signal used herein can be any physical signal or physical channel. Examples of downlink (DL) physical signals are reference signal (RS) such as Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), Channel State Information-Reference Signal (CSI-RS), Demodulation Reference Signal (DMRS) signals in SS / PBCH block (SSB), discovery reference signal (DRS), Cell Specific Reference Signal (CRS), Positioning Reference Signal (PRS), etc. RS may be periodic. For example, RS occasions carrying one or more RSs may occur with certain periodicity (e.g., 20 ms, 40 ms, etc.). The RS may also be aperiodic.

[0058] Each SSB carries New Radio-Primary Synchronization Signal (NR-PSS), New RadioSecondary Synchronization Signal (NR-SSS) and New Radio-Physical Broadcast Channel (NR- PBCH) in four successive symbols. One or multiple Synchronization Signal Blocks (SSBs) are transmitted in one SSB burst which is repeated with certain periodicity such as, for example, 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, and 160 ms. The UE is configured with information about SSB on cells of certain carrier frequency by one or more SS / PBCH block measurement timing configuration (SMTC) configurations. The SMTC configuration comprising parameters such as SMTC periodicity, SMTC occasion length in time or duration, SMTC time offset with regard to reference time (e.g., serving cell’s SFN) etc. Therefore, SMTC occasion may also occur with certain periodicity (e.g., 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, and 160 ms). Examples of uplink (UL) physical signals are reference signals such as Sounding Reference Signals (SRS), Demodulation Reference Signals (DMRS), etc. The term physical channel refers to any channel carrying higher layer information e.g. data, control etc. Examples of physical channels are Physical Broadcast Channel (PBCH), Physical Downlink Control Channel (PDCCH), Physical Downlink Shared Channel (PDSCH), Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), Physical Uplink Shared Channel (PUSCH), Short PUSCH (sPUCCH), Short PDSCH (sPDSCH), Short PUCCH (sPUCCH), Short PUSCH (sPUSCH), MTC PDCCH (MPDCCH), Narrowband PBCH (NPBCH), Narrowband PDCCH (NPDCCH), Narrowband PDSCH (NPDSCH), Narrowband PUSCH (NPUSCH), Enhanced PDCCH (E-PDCCH), etc.

[0059] The term time resource used herein may correspond to any type of physical resource or radio resource expressed in terms of length of time. Examples of time resources are: symbol, time slot, subframe, radio frame, TTI, interleaving time, slot, sub-slot, mini-slot, system frame number (SFN) cycle, hyper-SFN (H-SFN) cycle, etc.

[0060] Herein, the terms “mlAB”, “mobile IAB”, and “mlAB node” are used interchangeably.

[0061] Herein, the terms “mlAB-DU”, “mobile DU”, and “DU” are used interchangeably.

[0062] Herein, the terms “first / second logical mlAB-DU” and “source / target mlAB-DU” are used interchangeably.

[0063] Herein, the terms mobile IAB-MT and mlAB-MT are used interchangeably.

[0064] Herein, the terms mobile IAB-DU and mlAB-DU are used interchangeably.

[0065] Herein, the terms “CU”, “donor CU” and “donor node” are used interchangeably.

[0066] Herein, the notation “NG / S1 interface” means “NG interface or SI interface”. The same hold for “X2 / Xn interface”.

[0067] Herein, the terms “NG” and “NGAP” as well as “Xn” and “XnAP” are used interchangeably.

[0068] Herein, the terminology “UE connected to a mobile IAB” is used to characterize a UE that is in the coverage provided by the mobile IAB node.

[0069] Herein, the term “RACH-less HO” refers to a HO that is performed without executing a RACH procedure.

[0070] Though certain embodiments are written in the context of NR, the embodiments, techniques, solutions, and methods described herein can be applied without any loss of meaning also for other radio access technologies that can be used by a mobile IAB node.

[0071] Herein, the term “information related to a RACH-less handover of a UE” may include, but is not limited to, UE measurement report, chosen beam index, RSRP of the beam, PCI of the corresponding target cell etc.

[0072] As noted above, according to previous HO techniques (i.e., L3), it is usually the UE that determines during the RACH procedure the beam to use in the target cell. However, in the case where there is no RACH procedure involved, it would be not possible for the UE to determine which beam to use in the target (second) logical mlAB-DU. Thus, according to certain embodiments disclosed herein, the network determines and then informs the UE about which beam the UE would need to use towards the second logical mlAB-DU.

[0073] For example, according to certain embodiments, methods and systems are provided that enable the UE to receive information about the beam to be used in a target (second) logical DU during a RACH-less HO. These methods and systems may apply, for example, in the inter-CU mlAB-DU migration scenario with two logical DUs. Additionally, according to certain embodiments, methods and systems are provided for the network to determine which beam the UE should use when switching to a target (second) logical DU during a RACH-less handover (because of a DU migration).

[0074] For example, according to certain embodiments, when receiving the measurement report from the UE, the Source Donor CU selects a beam to be used by the UE during a RACH-less handover for mlAB, and indicates this selected beam to the Target Donor CU when triggering the handover procedure.

[0075] As another example, according to certain embodiments, when receiving the measurement report from the UE, the Source Donor CU sends a measurement report to the Target Donor CU when triggering the HO procedure. Then, the Target Donor CU selects a beam to be used by the UE during a RACH-less handover for mlAB.

[0076] Though certain embodiments are described based on a scenario that assumes inter-donor CU migration of a mobile IAB-DU (mlAB-DU), where the UEs served by the source logical mlAB-DU need to be handed over to the target logical mlAB-DU, the embodiments, techniques, solutions, and methods described herein can be applied to other scenarios.

[0077] FIGURE 3 illustrates an example method and signaling diagram 100 for a network to determine and inform a UE 102 about which beam the UE 102 would need to use towards the second logical mlAB-DU 104, according to certain embodiments.

[0078] As depicted, the method 100 begins at step 120 when the UE 102 provides measurement report from target beams projected by logical DU2 104 to donor CUI 108.

[0079] At step 130, the donor CUI 108 provides the information, either the selected beam or the measurement report, over Xn or over NG to donor CU2 112.

[0080] At step 140, the donor CU2 112 includes the target beam in the handover response including, if any, TA value that the UE 102 needs to adjust for the new beam. If no value is provided, the UE 102 reuses the same TA from the old beam.

[0081] At step 150, the donor CUI 108 forwards the information, the selected beam, and any additional information from donor CU2 112 to the UE 102.

[0082] At step 160, the UE 102 moves (performs handover) to donor CU2 112.

[0083] FIGURE 4 illustrates an example flow and signaling diagram 200 that includes a source donor CU 208 calculating and / or determining a beam to be used by a UE 202 during a mlAB RACH-less HO, according to certain embodiments.

[0084] As depicted, the example flow diagram 200 includes, at step 220, the UE 202 sending a measurement report to the Source Donor CU 208 (via the first logical mlAB DU 210). The measurement report may be sent by the UE 202 periodically or because a certain event has been triggered (e.g., channel strength on the serving cell is below a threshold). The measurement report may also be triggered because mlAB migration is taking place and all the UEs will be handed over to the second logical DU 204.

[0085] At step 225, the first logical mlAB DU 210, when receiving the measurement report from the UE 202, forwards it blindly (i.e., without reading or decoding it) to the Source Donor CU 208.

[0086] At steps 230 & 235, when receiving the UE measurement report, the Source Donor CU 208 determines that a mobile IAB RACH-less handover needs to be triggered towards a selected Target Donor CU 212, and also determines a beam for the UE 202 to be used when a mobile IAB RACH-less handover is triggered towards a Target Donor DU 204.

[0087] In a particular embodiment, the Source Donor CU 208 determines the beam according to or based on one or more of the following:

[0088] • the best beam (i.e., beam with the strongest channel conditions) is selected as the final beam,

[0089] • the beam belonging to a certain PCI is selected as final beam,

[0090] • the beam operating in a certain frequency is selected as the final beam,

[0091] • the beam belonging to a certain cell index is selected as the final beam,

[0092] • the beam with the strongest RSRP, or RSRQ, or SINR, or RS SI, is selected as the final beam,

[0093] • the best beam according to any of the criteria listed herein that is not allocated to any other UE (this is the case on when the network may want to assign a dedicated beam to each UE, or a sub-set of UEs).

[0094] In this context, a beam can be characterized according to one or more of the following:

[0095] • a beam identifier (ID),

[0096] • a Transmission Configuration Identifier (TCI) state ID,

[0097] • a TCI state configuration,

[0098] • a SSB ID, and

[0099] • a CSI-RS resource ID.

[0100] At step 240, once the Source Donor CU 208 determines a beam for the UE to be used when a mobile IAB RACH-less handover of the UE 202 is triggered towards a Target Donor DU 204, when sending an handover request message to the selected Target Donor CU 212, the Source Donor CU 208 also includes the just determined beam.

[0101] A steps 245 & 250, the Target Donor CU 212 sends a request to a second logical mlAB DU 204 to establish a UE context because on an upcoming mobile IAB RACH-less handover procedure, and, together with this request, it also includes the selected beam received by the Source Donor CU 208. The second logical mlAB DU 204 prepares and sends to the Target Donor CU 212 the lower layer configuration to be sent to the UE 202 as part of the handover command and includes also the selected beam received by the Target Donor CU 212. In some cases, if any TA adjustment is needed for the UE 202; simply because of known timing difference (e.g., new synchronization source taken for new logical DU2) between old beam and new beam then the new TA value or the delta adjustment can also be provided along with the selected beam.

[0102] At step 255, the Target Donor CU 212 sends to the Source Donor CU 208 the handover command (i.e., the RRCReconfiguration message) to send to the UE 202 to initiate the handover procedure towards the Target Donor CU 212 (and second logical mlAB DU 204).

[0103] At step 260, the Source Donor CU 208 sends to the UE 202 the handover command received from the Target Donor CU 212 including any adjustments (e.g., such as those related to the TA).

[0104] After this step, the UE 212 initiates the mobile IAB RACH-less handover procedure by applying the received RRCReconfiguration message (which also include an indication that this handover should be RACH-less). In this case, the random access procedure is not needed and the UE 212 can start transmitting / receiving with the Target Donor CU 212 (and second logical mlAB DU 204) via the indicated beam in the received RRCReconfiguration message, at step 265.

[0105] FIGURE 5 illustrates an example flow and signaling diagram 300 that includes a target donor CU 312 calculating and / or determining a beam to be used by a UE 302 during a mlAB RACH-less HO, according to certain embodiments. As depicted in FIGURE 5, at step 325, the UE 302 sends a measurement report to the Source Donor CU 308 (via the first logical mlAB DU 310). The measurement report may be sent by the UE 302 periodically or because a certain event has been triggered (e.g., channel strength on the serving cell is below a threshold). The measurement report may also be triggered because mlAB migration is taking place and all the UEs will be handed over to the second logical DU 304. For this latter case, a possible example is when a DU migration takes place (mlAB DU moves from a Source Donor CU 308 and a Target Donor CU 312) and an handover needs to be triggered for more than one UE 302. Therefore, the Source Donor CU 308 may broadcast a “DU migration ongoing” indication so UEs knows that in such case need to send a measurement report to the network.

[0106] At step 330, the first logical mlAB DU 310, when receiving the measurement report from the UE 302, forwards it blindly (i.e., without reading or decoding it) to the Source Donor CU 308.

[0107] At step 335, when receiving the UE measurement report, the Source Donor CU 308 determines that a mobile IAB RACH-less handover needs to be triggered towards a selected Target Donor CU 312. At step 340, the Source Donor CU 308 sends a handover request message to the selected Target Donor CU 312 and in the request includes also the measurement report received by the UE 302.

[0108] According to various particular embodiments, the Source Donor CU 308 when sending the measurement report may decide to include as part of this measurement report one or more of the following:

[0109] • the entire measurement report as received by the UE 302,

[0110] • measurement results (which are part of the measurement report) related to the Target Donor CU 312,

[0111] • measurement results (which are part of the measurement report) related to a particular cell that belongs to the Target Donor CU 312,

[0112] • measurement results (which are part of the measurement report) related to all the cells belonging to the second logical mlAB DU 304, and

[0113] • measurement results (which are part of the measurement report) related to one cell belonging to the second logical mlAB DU 304.

[0114] Additionally, the Source Donor CU 308 may, together with the measurement report received by the UE 302, also include a suggestion of a beam that UE 302 may use during a mobile IAB RACH-less handover procedure.

[0115] In particular embodiments, the Source Donor CU 308 determines the beam according to one or more of the following:

[0116] • the best beam (i.e., beam with the strongest channel conditions) is selected as the final beam,

[0117] • the beam belonging to a certain PCI is selected as final beam,

[0118] • the beam operating in a certain frequency is selected as the final beam,

[0119] • the beam belonging to a certain cell index is selected as the final beam,

[0120] • the beam with the strongest RSRP, or RSRQ, or SINR, or RS SI, is selected as the final beam, and

[0121] • the best beam according to any of the criteria listed herein that is not allocated to any other UE (this is the case on when the network may want to assign a dedicated beam to each UE, or a sub-set of UEs).

[0122] In particular embodiments, a beam can be characterized according to one or more of the following: a beam ID, a TCI state ID, a TCI state configuration, a SSB ID, and a CSI-RS resource ID,

[0123] At step 345, once the Target Donor CU 312 receives the handover request from the Source Donor CU 308, together with the measurement report received from the UE 302 and, eventually, a suggested beam to be used by the UE 302 when executing the mobile IAB RACH-less handover towards the Target Donor CU 312, the Target Donor CU 312 determines a beam to the used by the UE 302 when executing the mobile IAB RACH-less handover.

[0124] In particular embodiments, the target Donor CU 312 determines the beam according to one or more of the following:

[0125] • the best beam (i.e., beam with the strongest channel conditions) is selected as the final beam,

[0126] • the beam belonging to a certain PCI is selected as final beam,

[0127] • the beam operating in a certain frequency is selected as the final beam,

[0128] • the beam belonging to a certain cell index is selected as the final beam,

[0129] • the beam with the strongest RSRP, or RSRQ, or SINR, or RS SI, is selected as the final beam, and

[0130] • the beam suggested by the Source Donor CU is selected as the final beam.

[0131] In particular embodiments, a beam can be characterized according to one or more of the following:

[0132] • a beam ID,

[0133] • a TCI state ID,

[0134] • a TCI state configuration,

[0135] • a SSB ID, and

[0136] • a CSI-RS resource ID.

[0137] At steps 350 & 355, the Target Donor CU 312 sends a request to a second logical mlAB DU 304 to establish a UE context because on an upcoming mobile IAB RACH-less handover procedure, and, together with this request, it also includes the selected beam. The second logical mlAB DU 304 prepares and send to the Target Donor CU 312 the lower layer configuration to be sent to the UE 302 as part of the handover command and includes also the selected beam received by the Target Donor CU 312. In some cases, if any TA adjustment is needed for the UE 302; simply because of known timing difference (e.g., new synchronization source taken for new logical DU2) between old beam and new beam then the new TA value or the delta adjustment can also be provided along with the selected beam. At step 360, the Target Donor CU 360 sends to the Source Donor CU 308 the handover command (i.e., the RRCReconfiguration message) to be sent to the UE 302 to initiate the handover procedure towards the Target Donor CU 312 (and second logical mlAB DU 304).

[0138] At step 365, the Source Donor CU 308 sends to the UE 302 the handover command received by the Target Donor CU 312 including any adjustments (e.g., such as those related to the TA).

[0139] After this step, the UE 302 initiates the mobile IAB RACH-less handover procedure by applying the received RRCReconfiguration message (which also include an indication that this handover should be RACH-less). In this case, the random access procedure is not needed and the UE 302 can start transmitting / receiving with the Target Donor CU 312 (and second logical mlAB DU 304) via the indicated beam in the received RRCReconfiguration message, at step 365.

[0140] According to certain embodiments, the source donor CU 308 may send to the target donor CU 312, in a single message, information related to the RACH-less HO of a single UE 302. This beam related information can be sent through legacy UE related signaling such as HANDOVER PROCEDURES.

[0141] In other embodiments, the source donor CU 308 may send to the target donor CU 312, in a single message, information related to the RACH-less HO of multiple UEs 302. This beam information of multiple UEs 302 can be sent over legacy IAB related procedures or new procedures specifically for HO of multiple UEs 302.

[0142] NGAP-Related Aspects

[0143] In certain embodiments described above, a Xn-based UE handover was assumed. However, 3GPP specifications also support NG-based handover, in case there is no XnAP connectivity between the source and target node. According to the specifications, in this case, the source and target RAN node exchange the messages related to the UE HO via the NGAP interface with one AMF in-between (in case the AMF serves both the source and the target node), or via two or more AMFs in-between (in case different AMFs serve the source and target node).

[0144] In some embodiments, all considerations, techniques, embodiments, solutions, methods, etc. that are presented for the case of Xn-based handover equally apply for the case of NG-based UE handover.

[0145] Technical Specification Impact

[0146] All implementation examples are non -limiting. The proposed changes are shown in bold / underline. The added content can either be in the form of multiple IES or in the form of a single IE, consisting of one or more IES. In some embodiments, the newly added IE in the example can contain a list of UE measurements pertaining to one or more UEs, while in some embodiments it may contain a single UE measurement.

[0147] RRC implementation example in TS 38.331 v 17.5.0

[0148] An example ASN.l RRCReconfiguration change is provided below.

[0149] RRCReconf iguration-vl800-IEs : : = SEQUENCE { mlAB-TargetPCI-rlS INTEGER (0 . . 1007) , ssb-Index-r!8 SSB-Index , nonCriticalExtension SEQUENCE { }

[0150] OPTIONAL }

[0151] XnAP Implementation Example in TS 38.423 v 17.5.0

[0152] An example change is provided below.

[0153] 9.1.1.1 HANDOVER REQUEST

[0154] This message is sent by the source NG-RAN node to the target NG-RAN node to request the preparation of resources for a handover.

[0155] Direction: source NG-RAN node — target NG-RAN node.

[0156] NGAP implementation example in TS 38.413 v 17.5.0 An example ASN.1 RRCReconfiguration change is provided below.

[0157] 9.3.1.29 Source NG-RAN Node to Target NG-RAN Node Transparent Container This IE is produced by the source NG-RAN node and is transmitted to the target NG-RAN node. For inter-system handovers to 5G, the IE is transmitted from the external handover source to the target NG-RAN node.

[0158] This IE is transparent to the 5GC.

[0159] FIGURE 6 shows an example of a communication system 400 in accordance with some embodiments. In the example, the communication system 400 includes a telecommunication network 402 that 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 be generally referred to as network nodes 410), or any other similar 3rdGeneration Partnership Project (3GPP) access node or non-3GPP access point. The network nodes 410 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 412a, 412b, 412c, and 412d (one or more of which may be generally referred to as UEs 412) to the core network 406 over one or more wireless connections.

[0160] Example wireless communications over 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 conveying information without the use of wires, cables, or other material conductors. Moreover, in different 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 may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 400 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0161] The UEs 412 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 410 and other communication devices. Similarly, the network nodes 410 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 412 and / or with other network nodes or equipment in the telecommunication network 402 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 402.

[0162] In the depicted example, the core network 406 connects the network nodes 410 to one or more hosts, such as host 416. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 406 includes one more core network nodes (e.g., core network node 408) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 408. Example core network nodes include functions of one or more of a 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 De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0163] The host 416 may be under the ownership or control of a service provider other than an operator or provider of the access network 404 and / or the telecommunication network 402, and may be operated by the service provider or on behalf of the service provider. The host 416 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0164] As a whole, the communication system 400 of FIGURE 6 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0165] In some examples, the telecommunication network 402 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 402 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 402. For example, the telecommunications network 402 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC)ZMassive loT services to yet further UEs.

[0166] In some examples, the UEs 412 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 404 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 404. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi -radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0167] In the example, the hub 414 communicates with the access network 404 to facilitate indirect communication between one or more UEs (e.g., UE 412c and / or 412d) and network nodes (e.g., network node 410b). In some examples, the hub 414 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 414 may be a broadband router enabling access to the core network 406 for the UEs. As another example, the hub 414 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 410, or by executable code, script, process, or other instructions in the hub 414. As another example, the hub 414 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 414 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 414 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 414 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 414 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.

[0168] The hub 414 may have a constant / persistent or intermittent connection to the network node 410b. The hub 414 may also allow for a different communication scheme and / or schedule between the hub 414 and UEs (e.g., UE 412c and / or 412d), and between the hub 414 and the core network 406. In other examples, the hub 414 is connected to the core network 406 and / or one or more UEs via a wired connection. Moreover, the hub 414 may be configured to connect to an M2M service provider over the access network 404 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 410 while still connected via the hub 414 via a wired or wireless connection. In some embodiments, the hub 414 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 410b. In other embodiments, the hub 414 may be a nondedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 410b, but which is additionally capable of operating as a communication start and / or end point for certain data channels. FIGURE 7 shows a UE 500 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0169] A UE may support device -to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0170] The UE 500 includes processing circuitry 502 that is operatively coupled via a bus 504 to an input / output interface 506, a power source 508, a memory 510, a communication interface 512, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in FIGURE 7. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0171] The processing circuitry 502 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 510. The processing circuitry 502 may be implemented as one or more hardware -implemented state machines (e.g., in discrete logic, field- programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 502 may include multiple central processing units (CPUs).

[0172] In the example, the input / output interface 506 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 500. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0173] In some embodiments, the power source 508 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 508 may further include power circuitry for delivering power from the power source 508 itself, and / or an external power source, to the various parts of the UE 500 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 508. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 508 to make the power suitable for the respective components of the UE 500 to which power is supplied.

[0174] The memory 510 may be or be configured to include memory such as 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, flash drives, and so forth. In one example, the memory 510 includes one or more application programs 514, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 516. The memory 510 may store, for use by the UE 500, any of a variety of various operating systems or combinations of operating systems.

[0175] The memory 510 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 510 may allow the UE 500 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 510, which may be or comprise a device -readable storage medium.

[0176] The processing circuitry 502 may be configured to communicate with an access network or other network using the communication interface 512. The communication interface 512 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 522. The communication interface 512 may include one ormore transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 518 and / or a receiver 520 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 518 and receiver 520 may be coupled to one or more antennas (e.g., antenna 522) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0177] In the illustrated embodiment, communication functions of the communication interface 512 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / intemet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth. Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 512, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0178] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0179] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or itemtracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 500 shown in FIGURE 7.

[0180] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0181] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0182] FIGURE 8 shows a network node 600 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NRNodeBs (gNBs)).

[0183] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0184] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs). The network node 600 includes a processing circuitry 602, a memory 604, a communication interface 606, and a power source 608. The network node 600 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 600 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 600 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 604 for different RATs) and some components may be reused (e.g., a same antenna 610 may be shared by different RATs). The network node 600 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 600, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 600.

[0185] The processing circuitry 602 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 600 components, such as the memory 604, to provide network node 600 functionality.

[0186] In some embodiments, the processing circuitry 602 includes a system on a chip (SOC). In some embodiments, the processing circuitry 602 includes one or more of radio frequency (RF) transceiver circuitry 612 and baseband processing circuitry 614. In some embodiments, the radio frequency (RF) transceiver circuitry 612 and the baseband processing circuitry 614 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 612 and baseband processing circuitry 614 may be on the same chip or set of chips, boards, or units.

[0187] The memory 604 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 602. The memory 604 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 602 and utilized by the network node 600. The memory 604 may be used to store any calculations made by the processing circuitry 602 and / or any data received via the communication interface 606. In some embodiments, the processing circuitry 602 and memory 604 is integrated.

[0188] The communication interface 606 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 606 comprises port(s) / terminal(s) 616 to send and receive data, for example to and from a network over a wired connection. The communication interface 606 also includes radio frontend circuitry 618 that may be coupled to, or in certain embodiments a part of, the antenna 610. Radio front-end circuitry 618 comprises filters 620 and amplifiers 622. The radio front-end circuitry 618 may be connected to an antenna 610 and processing circuitry 602. The radio frontend circuitry may be configured to condition signals communicated between antenna 610 and processing circuitry 602. The radio front-end circuitry 618 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 618 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 620 and / or amplifiers 622. The radio signal may then be transmitted via the antenna 610. Similarly, when receiving data, the antenna 610 may collect radio signals which are then converted into digital data by the radio front-end circuitry 618. The digital data may be passed to the processing circuitry 602. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0189] In certain alternative embodiments, the network node 600 does not include separate radio front-end circuitry 618, instead, the processing circuitry 602 includes radio front-end circuitry and is connected to the antenna 610. Similarly, in some embodiments, all or some of the RF transceiver circuitry 612 is part of the communication interface 606. In still other embodiments, the communication interface 606 includes one or more ports or terminals 616, the radio front-end circuitry 618, and the RF transceiver circuitry 612, as part of a radio unit (not shown), and the communication interface 606 communicates with the baseband processing circuitry 614, which is part of a digital unit (not shown). The antenna 610 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 610 may be coupled to the radio front-end circuitry 618 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 610 is separate from the network node 600 and connectable to the network node 600 through an interface or port.

[0190] The antenna 610, communication interface 606, and / or the processing circuitry 602 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 610, the communication interface 606, and / or the processing circuitry 602 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0191] The power source 608 provides power to the various components of network node 600 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 608 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 600 with power for performing the functionality described herein. For example, the network node 600 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 608. As a further example, the power source 608 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0192] Embodiments of the network node 600 may include additional components beyond those shown in FIGURE 8 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 600 may include user interface equipment to allow input of information into the network node 600 and to allow output of information from the network node 600. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 600.

[0193] FIGURE 9 is a block diagram illustrating a virtualization environment 700 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 700 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized.

[0194] Applications 702 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 700 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0195] Hardware 704 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 706 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 708a and 708b (one or more of which may be generally referred to as VMs 708), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 706 may present a virtual operating platform that appears like networking hardware to the VMs 708.

[0196] The VMs 708 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 706. Different embodiments of the instance of a virtual appliance 702 may be implemented on one or more of VMs 708, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0197] In the context of NFV, a VM 708 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 708, and that part of hardware 704 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 708 on top of the hardware 704 and corresponds to the application 702.

[0198] Hardware 704 may be implemented in a standalone network node with generic or specific components. Hardware 704 may implement some functions via virtualization. Alternatively, hardware 704 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 710, which, among others, oversees lifecycle management of applications 702. In some embodiments, hardware 704 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 712 which may alternatively be used for communication between hardware nodes and radio units.

[0199] FIGURE 10 illustrates an example method 800 by a UE for mlAB, according to certain embodiments. In the illustrated embodiment, the method includes a receiving step at 802. For example, at step 802, the UE may receive information indicating a beam to be used in a target DU during a HO of the UE from a first cell to a second cell.

[0200] FIGURE 11 illustrates an example method 900 by a CU for indicating at least one access beam for mlAB, according to certain embodiments. In the illustrated embodiment, the method includes a transmitting step at 902. For example, at step 902, the CU may transmit, to a UE, information indicating a beam to be used in a target DU during a HO of the UE from a first cell to a second cell.

[0201] FIGURE 12 illustrates an example method 1000 by a target CU for indicating at least one access beam for mlAB, according to certain embodiments. In the illustrated embodiment, the method includes a receiving and / or transmitting step at 1002. For example, at step 1002, the target CU may receive from a source CU and / or transmit to the source CU, information indicating a beam to be used in a target DU during a HO of a UE from a first cell to a second cell.

[0202] FIGURE 13 illustrates an example method 1100 by a UE, for mlAB, according to certain embodiments. As depicted, the method includes a step 1102 where the UE receives information indicating a beam to be transmitted from a target DU during a HO of the UE from a first cell to a second cell. The HO comprises a mlAB RACH-less HO. In a particular embodiment, the UE executes the HO to the second cell without performing RACH procedure.

[0203] In a particular embodiment, the beam is associated with and / or the information identifies the beam by at least one of: a beam identifier; a TCI state identifier; a TCI state configuration; a SSB ID; and a CSI-RS resource identifier.

[0204] In a particular embodiment, the UE receives, 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.

[0205] In a particular embodiment, the information is received from a source CU via a source DU.

[0206] In a particular embodiment, at least one of: the target DU (104) is a target donor DU, the source DU (110) is a source donor DU, a target CU (112) is a target donor CU, and the source CU (108) is a source donor CU.

[0207] In a particular embodiment, at least one of the target DU and the source DU is a logical DU.

[0208] In a particular embodiment, prior to receiving the information, the UE receives, from the target DU, a plurality of beams, performs at least one measurement procedure based on each of the plurality of beams, and transmits, to the source CU, a measurement report comprising at least one value associated with the at least one measurement performed by the UE for at least one of the plurality of beams from the target DU.

[0209] FIGURE 14 illustrates an example method 1200 by a source CU for mlAB, according to certain embodiments. As depicted, the method includes, at step 1402, the source CU transmitting, to a UE, information indicating a beam to be transmitted from a target DU during a Handover of the UE from a first cell to a second cell. The HO comprises a mlAB RACH-less HO.

[0210] In a particular embodiment, the beam is associated with and / or the information identifies the beam by at least one of: a beam identifier; a TCI state identifier; a TCI state configuration; a SSB identifier; and a CSI-RS resource identifier.

[0211] In a particular embodiment, at least one TA value for the beam is transmitted to the UE 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.

[0212] In a particular embodiment, the information is transmitted to the UE via a source DU.

[0213] In a particular embodiment, at least one of: the target DU (104) is a target donor DU, the source DU (110) is a source donor DU, a target CU (112) is a target donor CU, and the source CU (108) is a source donor CU. In a particular embodiment, at least one of the target DU and the source DU is a logical

[0214] DU.

[0215] In a particular embodiment, the source CU determines that the mlAB RACH-less handover is to be triggered towards a target CU.

[0216] In a particular embodiment, prior to transmitting the information to the UE, the source CU receives a measurement report associated with the UE. The measurement report comprises at least one value associated with at least one measurement performed by the UE for at least one beam transmitted by the target DU.

[0217] In a particular embodiment, the source CU transmits the 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, 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.

[0218] In a particular embodiment, the source CU transmits, with the measurement report or the at least one value associated with the measurement report, a suggested beam to be transmitted from the target DU.

[0219] In a particular embodiment, the suggested beam is selected by the source CU based on at least one of: a value indicating that the suggested beam has a highest channel quality; the suggested beam is associated with a particular PCI; the suggested beam operates in at a particular frequency and / or within a particular frequency range; the suggested beam is associated with a particular cell index; the suggested beam has a strongest Reference Signal Received Power, Reference Signal Received Quality, Signal Interference to Noise Ratio, and / or Received Signal Strength Indicator; the suggested beam is not allocated to another UE; and the suggested beam is allocated to a subset of UEs to which the UE belongs.

[0220] In a particular embodiment, the suggested beam is associated with and / or the suggested beam is indicated by at least one of: a beam identifier; a TCI state identifier; a TCI state configuration; a SSB identifier; and a CSI-RS resource identifier.

[0221] In a particular embodiment, the measurement report or the at least one value associated with the measurement report is transmitted to the target CU in or with a handover request message, and

[0222] In a particular embodiment, the source CU receives, from the target CU, a handover response message comprising the information indicating the beam to be transmitted from the target DU. In a particular embodiment, the response message comprises 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.

[0223] FIGURE 15 illustrates a method by a target CU for mlAB, according to certain embodiments. As depicted, the method includes the target CU receiving, at step 1302, from a source CU and / or transmitting to the source CU information indicating a beam to be transmitted from a target DU during a HO of a UE from a first cell to a second cell. The HO comprises an mlAB RACH-less HO.

[0224] In a particular embodiment, the beam is associated with and / or the information identifies the beam by at least one of: a beam identifier; a TCI state identifier; a TCI state configuration; a SSB identifier; and a CSI-RS resource identifier.

[0225] In a particular embodiment, at least one TA value for the beam is transmitted to the UE 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.

[0226] In a particular embodiment, at least one of: the target DU is a target donor DU, a source DU is a source donor DU, the target CU is a target donor CU, and the source CU is a source donor CU.

[0227] In a particular embodiment, at least one of the target DU and the source DU is a logical DU.

[0228] In a particular embodiment, the target CU selects the beam to be transmitted during the HO of the UE.

[0229] In a particular embodiment, the beam is selected based on at least one of: a value indicating that the beam has a highest channel quality; the beam is associated with a particular PCI; the beam operates in at a particular frequency and / or within a particular frequency range; the beam is associated with a particular cell index; the beam has a strongest Reference Signal Received Power or Reference Signal Received Quality or Signal Interference to Noise Ratio, or Received Signal Strength Indicator; the beam is not allocated to another UE; and the beam is allocated to a subset of UEs to which the UE belongs.

[0230] In a particular embodiment, prior to transmitting the information to the source CU, the target CU receives a measurement report and / or at least one value associated with a measurement report from the source CU. 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, and the beam is selected based on the measurement report and / or the at least one value associated with the measurement report. In a particular embodiment, 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 that is 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.

[0231] In a particular embodiment, the target CU receives, with the measurement report or the at least one value associated with the measurement report, a suggested beam to be used with the target DU.

[0232] In a particular embodiment, the suggested beam is associated with and / or the suggested beam is indicated by at least one of: a beam identifier; a TCI state identifier; a TCI state configuration; a SSB identifier; and a CSI-RS resource identifier.

[0233] In a particular embodiment, the target CU transmits, 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.

[0234] In a particular embodiment, the target CU receives, from the target DU, at least one of: 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.

[0235] Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0236] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer-readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

[0237] EXAMPLE EMBODIMENTS

[0238] Group A Example Embodiments

[0239] Example Embodiment Al. A method by a user equipment for determining access beams during a Random Access Channel-less Handover (HO) for mobile-integrated Access and Backhaul (mlAB), the method comprising: any of the user equipment steps, features, or functions described above, either alone or in combination with other steps, features, or functions described above.

[0240] Example Embodiment A2. The method of the previous embodiment, further comprising one or more additional user equipment steps, features or functions described above.

[0241] Example Embodiment A3. The method of any of the previous embodiments, further comprising: providing user data; and forwarding the user data to a host computer via the transmission to the network node.

[0242] Group B Example Embodiments

[0243] Example Embodiment Bl. A method performed by a network node for determining access beams during a Random Access Channel-less Handover (HO) for mobile-integrated Access and Backhaul (mlAB), the method comprising: any of the network node steps, features, or functions described above, either alone or in combination with other steps, features, or functions described above.

[0244] Example Embodiment B2. The method of the previous embodiment, further comprising one or more additional network node steps, features or functions described above. Example Embodiment B3. The method of any of the previous embodiments, further comprising: obtaining user data; and forwarding the user data to a host or a user equipment.

[0245] Group C Example Embodiments

[0246] Example Embodiment Cl. A method by a user equipment (UE) for mobile-integrated Access and Backhaul (mlAB), the method comprising: receiving information indicating a beam to be used in a target Distributed Unit (DU) during a Handover (HO) of the UE from a first cell to a second cell.

[0247] Example Embodiment C2. The method of Example embodiment Cl, wherein the information is received from a Source Centralized Unit (CU) via a source DU.

[0248] Example Embodiment C3. The method of Example Embodiment C2, wherein at least one of: the source CU communicates with the source DU via a first Fl connection; and a target CU communicates with the target DU via a second Fl connection.

[0249] Example Embodiment C4. The method of any one of Example Embodiments C2 to C3, wherein the target DU and the source DU are associated with a mobile-IAB node.

[0250] Example Embodiment C5. The method of any one of Example Embodiments C2 to C4, wherein at least one of: 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.

[0251] Example Embodiment C6. The method of any one of Example Embodiments C2 to C5, wherein at least one of the target DU and the source DU is a logical DU.

[0252] Example Embodiment C7. The method of any one of Example Embodiments Cl to C6, wherein the information is received in a RRCReconfiguration message.

[0253] Example Embodiment C8. The method of any one of Example Embodiments Cl to C7, wherein the HO comprises a mobile-IAB (mlAB) Random Access Channel-less (RACH-less) HO.

[0254] Example Embodiment C9. The method of any one of Example Embodiments Cl to C8, comprising: prior to receiving the information, transmitting a measurement report to the source CU.

[0255] Example Embodiment CIO. The method of Example Embodiment C9, comprising: receiving, from the target DU, a plurality of beams; performing at least one measurement procedure based on each of the plurality of beams; and generating the measurement report.

[0256] Example Embodiment Cl 1. The method of Example Embodiment CIO, wherein the measurement report is transmitted to the source CU based on a condition being fulfilled or a triggering event being detected.

[0257] Example Emboidment Cl 2. The method of Example Embodiment CI I, wherein the condition is fulfilled and / or the triggering event is detected when at least one of: a period of time has lapsed since a previous measurement report was transmitted; a value indicating a channel strength of the first cell is below a threshold; a mlAB migration requires all UEs associated with the source CU to be migrated to the target CU; and a mlAB migration requires all UEs associated with the source DU to be migrated to the target DU; and a mlAB migration requires all UEs associated with the first cell to be migrated to the second cell.

[0258] Example Embodiment Cl 3. The method of any one of Example Embodiments C9 to Cl 2, wherein the measurement report comprises a plurality of values, each of the plurality of values being associated with a measurement performed by the UE for a respective one of the plurality of beams from the target DU.

[0259] Example Embodiment Cl 4. The method of Example Embodiment Cl 3, wherein the plurality of values comprises at least one of: a channel quality value; a Reference Signal Received Power (RSRP); a Reference Signal Received Quality (RSRQ); a Signal Interference to Noise Ratio (SINR); and a Received Signal Strength Indicator (RSSI).

[0260] Example Embodiment Cl 5. The method of any one of Example Embodiments C 13 to Cl 4, wherein at least one value of the plurality of values is identified as being associated with at least one of: a PCI associated to a particular beam; a beam operating in a particular frequency and / or within a particular frequency range; a beam that is associated with a particular cell index; a beam that is not allocated to another UE; and a beam that is allocated to a subset of UEs to which the UE belongs.

[0261] Example Embodiment Cl 6. The method of any one of Example Embodiments Cl to Cl 5, wherein the beam is associated with and / or the information identifies the beam by 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.

[0262] Example Embodiment Cl 7. The method of any one of Example Embodiments Cl to Cl 6, comprising receiving, with the information, at least one TA value for the beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0263] Example Embodiment Cl 8. The method of any one of Example Embodiments Cl to Cl 7, comprising receiving, with the information, an indication that the HO comprises a RACH-less HO from the first cell to the second cell.

[0264] Example Embodiment Cl 9. The method of Example Embodiments Cl to C18, further comprising: providing user data; and forwarding the user data to a host via the transmission to the network node. Example Embodiment C20.A user equipment comprising processing circuitry configured to perform any of the methods of Example Embodiments Cl to Cl 9.

[0265] Example Embodiment C21. A user equipment configured to perform any of the methods of Example Embodiments Cl to C 19.

[0266] Example Embodiment C22.A wireless device comprising processing circuitry configured to perform any of the methods of Example Embodiments Cl to Cl 9.

[0267] Example Embodiment C23. A computer program comprising instructions which when executed on a computer perform any of the methods of Example Embodiments Cl to C 19.

[0268] Example Embodiment C24. A computer program product comprising computer program, the computer program comprising instructions which when executed on a computer perform any of the methods of Example Embodiments Cl to Cl 9.

[0269] Example Embodiment C25. A non-transitory computer readable medium storing instructions which when executed by a computer perform any of the methods of Example Embodiments Cl to Cl 9.

[0270] Group D Example Embodiments

[0271] Example Embodiment DI. A method by a source Centralized Unit (CU) for indicating at least one access beam for mobile-integrated Access and Backhaul (mlAB), the method comprising: transmitting, to a User Equipment (UE), information indicating a beam to be used in a target Distributed Unit (DU) during a Handover (HO) of the UE from a first cell to a second cell.

[0272] Example Embodiment D2. The method of Example Embodiment DI, wherein at least one of: the source CU communicates with a source DU via a first Fl connection; and a target CU communicates with the target DU via a second Fl connection.

[0273] Example Embodiment D3. The method of Example Embodiment D2, wherein the target DU and the source DU are associated with a mobile-IAB node.

[0274] Example Embodiment D4. The method of any one of Example Embodiments D2 to D3, wherein at least one of: 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.

[0275] Example Embodiment D5. The method of any one of Example Embodiments D 1 to D4, wherein at least one of the target DU and the source DU is a logical DU.

[0276] Example Embodiment D6. The method of any one of Example Embodiments DI to D5, wherein the information is transmitted to the UE in a RRCReconfiguration message.

[0277] Example Embodiment D7. The method of any one of Example Embodiments DI to D6, wherein at least one of: the HO comprises a mobile-IAB (mlAB) Random Access Channel-less (RACH-less) HO, and / or the method comprises determining that a mlAB RACH-less handover is to be triggered towards the target CU.

[0278] Example Embodiment D8. The method of any one of Example Embodiments DI to D7, comprising: prior to transmitting the information to the UE, receiving a measurement report associated with the UE, and wherein at least one of: the measurement report comprises a plurality of values, each of the plurality of values being associated with a measurement performed by the UE for a respective one of a plurality of beams projected by the target DU, and / or the measurement report is received via the source DU via an Fl connection.

[0279] Example Embodiment D9. The method of Example Embodiment D8, comprising: based on the measurement report comprising the plurality of values, selecting the beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0280] Example Embodiment DIO. The method of Example Embodiment D9, wherein the beam is selected to be used based on at least one of: a value indicating that the beam has a highest channel quality; the beam is associated with a particular PCI; the beam operates in at a particular frequency and / or within a particular frequency range; the beam is associated with a particular cell index; the beam has a strongest Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ) or Signal Interference to Noise Ratio (SINR), or Received Signal Strength Indicator (RSSI); the beam is not allocated to another UE; and the beam is allocated to a subset of UEs to which the UE belongs.

[0281] Example Embodiment D 11. The method of any one of Example Embodiments D9 to DIO, wherein the beam is associated with and / or the information identifies the beam by 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.

[0282] Example Embodiment D12. The method of Example Embodiment D9, comprising transmitting, to a target CU, the information indicating the beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0283] Example Embodiment D13. The method of Example Embodiment DI 2, wherein the information is transmitted in a handover request message associated with the UE.

[0284] Example Embodiment D14. The method of Example Embodiment DI 3, wherein the information is transmitted in a handover request message associated with a plurality of UEs, and wherein the information indicates: the beam is to be used in 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 to be used in the target DU during the HO of at least one additional UE from the first cell to the second cell. Example Embodiment D 15. The method of any one of Example Embodiments D 12 to D14, wherein the information is transmitted to the target CU via an Xn interface or NG interface.

[0285] Example Embodiment DI 6. The method of any one of Example Embodiments D 12 to D15, comprising receiving response message from the target CU, and wherein at least one of: the response message comprises at least one of: a handover response message, a handover request acknowledge message, a handover command message, and a RRCReconfiguration message; the response message comprises the information indicating the beam to be 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 to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0286] Example Embodiment DI 7. The method of Example Embodiment DI 6, wherein at least one TA value for the beam is transmitted to the UE with the information indicating the beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0287] Example Embodiment D18. The method of Example Embodiment 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, from the target CU, the information indicating the beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0288] Example Embodiment D19. The method of Example Embodiment D18, wherein transmitting the measurement report or the at least one value associated with the measurement report comprises transmitting at least one of: 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 the second cell that is 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 at least one value associated with and / or related to the second cell.

[0289] Example Embodiment D20. The method of any one of Example Embodiments D18 to DI 9, comprising transmitting, with the measurement report or the at least one value associated with the measurement report, a suggested beam to be used with the target DU.

[0290] Example Embodiment D21. The method of Example Embodiment D20, wherein the suggested beam is selected by the source CU based on at least one of: a value indicating that the beam has a highest channel quality; the beam is associated with a particular PCI; the beam operates in at a particular frequency and / or within a particular frequency range; the beam is associated with a particular cell index; the beam has a strongest Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ) or Signal Interference to Noise Ratio (SINR), or Received Signal Strength Indicator (RSSI); the beam is not allocated to another UE; and the beam is allocated to a subset of UEs to which the UE belongs.

[0291] Example Embodiment D22. The method of any one of Example Embodiments D20 to D21, wherein the suggested beam is associated with and / or the suggested beam is indicated by 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.

[0292] Example Embodiment D23. The method of any one of Example Embodiments DI 8 to D22, wherein the measurement report or the at least one value associated with the measurement report is transmitted to the target CU in or with a handover request message.

[0293] Example Embodiment D24. The method of Example Embodiment D23, wherein the handover request message is associated with a plurality of UEs (including the UE), and wherein the handover request message comprises at least one of: a plurality of measurement reports, wherein each measurement report is associated with an associated one of the plurality of UEs; a plurality of measurement values, wherein each measurement value is associated with an associated one of the plurality of UEs; a suggested beam to be used in the target DU during HO of the plurality of UEs from the first cell to the second cell; and a plurality of suggested beams to be used in the target DU during HO of the plurality of UEs from the first cell to the second cell, wherein each suggested beam is associated with an associated one of the plurality of UEs.

[0294] Example Embodiment D25. The method of any one of Example Embodiments D 18 to D24, wherein the measurement report or the at least one value associated with the measurement report is transmitted to the target CU via an Xn interface or NG interface.

[0295] Example Embodiment D26. The method of any one of Example Embodiments D 18 to D25, wherein at least one of: the information indicating the beam to be used in the target DU is received from the target CU in a response message; the response message comprising at least one of: a handover response message, a handover request acknowledge message, a handover command message, and a RRCReconfiguration message; and the response message comprises at least one TA value for the beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0296] Example Embodiment D27. The method of Example Embodiment D26, wherein at least one TA value for the beam is transmitted to the UE with the information indicating the beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0297] Example Embodiment D28. The method of any one of Example Embodiments D26 to D27, wherein the response message indicates at least one of: that the beam is to be used in the target DU during the HO of a plurality of UEs (including the UE) from the first cell to the second cell; and at least one additional beam to be used in the target DU during the HO of at least one additional UE from the first cell to the second cell.

[0298] Example Embodiment D29. The method of any one of Example Embodiments D 1 to D28, further comprising : obtaining user data; and forwarding the user data to a host or a user equipment.

[0299] Example Embodiment D30. A network node comprising processing circuitry configured to perform any of the methods of Example Embodiments DI to D29.

[0300] Example Embodiment D31. A network node configured to perform any of the methods of Example Embodiments DI to D29.

[0301] Example Embodiment D32. A computer program comprising instructions which when executed on a computer perform any of the methods of Example Embodiments DI to D29.

[0302] Example Embodiment D33. A computer program product comprising computer program, the computer program comprising instructions which when executed on a computer perform any of the methods of Example Embodiments DI to D29.

[0303] Example Embodiment D34. A non-transitory computer readable medium storing instructions which when executed by a computer perform any of the methods of Example Embodiments DI to D29.

[0304] Group E Example Embodiments

[0305] Example Embodiment El. A method by a target Centralized Unit (CU) for indicating at least one access beam for mobile-integrated Access and Backhaul (mlAB), the method comprising at least one of: receiving from a source CU and / or transmitting to the source CU, information indicating a beam to be used in a target Distributed Unit (DU) during a handover (HO) of a User Equipment (UE) from a first cell to a second cell.

[0306] Example Embodiment E2. The method of Example Embodiment E 1 , wherein at least one of: the source CU communicates with a source DU via a first Fl connection; and the target CU communicates with the target DU via a second Fl connection.

[0307] Example Embodiment E3. The method of Example Embodiment E2, wherein the target DU and the source DU are associated with a mobile-IAB node.

[0308] Example Embodiment E4. The method of any one of Example Embodiments E2 to E3, wherein at least one of: 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.

[0309] Example Embodiment E5. The method of any one of Example Embodiments El to E4, wherein at least one of the target DU and the source DU is a logical DU.

[0310] Example Embodiment E6. The method of any one of Example Embodiments El to E5, wherein the HO comprises a mobile-IAB (mlAB) Random Access Channel-less (RACH-less) HO.

[0311] Example Embodiment E7. The method of any one of Example Embodiments El to E6, wherein the information indicating the beam to be used in the target DU is transmitted from the target CU to the source CU.

[0312] Example Embodiment E8. The method of Example Emboidment E7, comprising: prior to transmitting the information to the source CU, receiving a measurement report and / or at least one value associated with a measurement report from the source CU, the measurement report and / or the at least one value being associated with the UE for HO from the first cell to the second cell, and based on the measurement report and / or the at least one value associated with the measurement report, selecting the beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0313] Example Embodiment E9. The method of Example Embodiment E8, wherein at least one of: the measurement report comprises a plurality of values, each of the plurality of values being associated with a measurement performed by the UE for a respective one of a plurality of beams projected by the target DU, and / or the measurement report is received via an Xn or NG connection.

[0314] Example Embodiment El 0. The method of any one of Example Embodiments E8 to E9, wherein the beam is selected by the target CU to be used during the HO of the UE based on at least one of: a value indicating that the beam has a highest channel quality; the beam is associated with a particular PCI; the beam operates in at a particular frequency and / or within a particular frequency range; the beam is associated with a particular cell index; the beam has a strongest Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ) or Signal Interference to Noise Ratio (SINR), or Received Signal Strength Indicator (RSSI); the beam is not allocated to another UE; and the beam is allocated to a subset of UEs to which the UE belongs.

[0315] Example Embodiment El l. The method of any one of Example Embodiments E8 to E10, wherein 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 that is associated with the UE.

[0316] Example Embodiment El 2. The method of any one of Example Embodiments E8 to E10, wherein 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 that is associated with a plurality of UEs, and wherein the information transmitted to the source CU indicates: the beam is to be used in 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 to be used in the target DU during the HO of at least one additional UE from the first cell to the second cell.

[0317] Example Embodiment El 3. The method of any one of Example Embodiments E8 to El 2, comprising receiving, with the measurement report or the at least one value associated with the measurement report, a suggested beam to be used with the target DU.

[0318] Example Embodiment El 4. The method of Example Embodiment El 3, wherein the suggested beam is associated with and / or the suggested beam is indicated by 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.

[0319] Example Embodiment El 5. The method of any one of Example Embodiments E7 to El 4, wherein the beam is associated with and / or the information transmitted to the source CU identifies the beam by 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.

[0320] Example Embodiment El 6. The method of any one of Example Embodiments E7 to E15, wherein the information indicating the beam to be used in the target DU is transmitted to the source CU in a response message, and wherein the response message comprises at least one of: a handover response message, a handover request acknowledge message, a handover command message, and a RRCReconfiguration message.

[0321] Example Embodiment El 7. The method of Example Embodiment El 6, wherein the response message comprises at least one TA value for the beam is transmitted to the UE with the information indicating the beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0322] Example Embodiment El 8. The method of any one of Example Embodiments El to E6, wherein the information indicating the beam to be used in the target DU is received from the source CU.

[0323] Example Embodiment El 9. The method of Example Embodiment E18, wherein the information indicating the beam comprises 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.

[0324] Example Embodiment E20.The method of any one of Example Embodiments El 8 to E 19, wherein the information indicating the beam to be used in the target DU is received by the target CU in or with a handover request message associated with the UE.

[0325] Example Embodiment E21.The method of any one of Example Embodiments El 8 to E 19, wherein the information is transmitted in a handover request message associated with a plurality of UEs (including the UE), and wherein the information indicates: the beam is to be used in 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 to be used in the target DU during the HO of at least one additional UE from the first cell to the second cell.

[0326] Example Embodiment E22.The method of any one of Example Embodiments E18 to E21, wherein the information is received from the source CU via an Xn interface or NG interface.

[0327] Example Embodiment E23.The method of any one of Example Embodiments E17 to E22, comprising transmitting a response message from the target CU, and wherein at least one of: the response message comprises at least one of: a handover response message, a handover request acknowledge message, a handover command message, and a RRCReconfiguration message; the response message comprises the information indicating the beam to be 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 to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0328] Example Embodiment E24.The method of any one of Example Embodiments El to E23, comprising transmitting, to the target DU, the information indicating the beam to be used in the target DU during the HO of the UE from the first cell to the second cell.

[0329] Example Embodiment E25. The method of Example Embodiment E24, wherein the information indicating the beam to be used in the target DU is transmitted to the target DU with or in a request to establish a UE context for the UE.

[0330] Example Emboidment E26.The method of any one of Example Embodiments E24 to E25, comprising receiving, from the target DU, at least one of: a lower layer configuration to be used during the HO of the UE from the first cell to the second cell; the information indicating the beam to be used in 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.

[0331] Example Embodiment E27.The method of any one of Example Embodiments El to E26, further comprising : obtaining user data; and forwarding the user data to a host or a user equipment.

[0332] Example Embodiment E28. A network node comprising processing circuitry configured to perform any of the methods of Example Embodiments El to E27.

[0333] Example Embodiment E29. A network node configured to perform any of the methods of Example Embodiments El to E27. Example Embodiment E30. A computer program comprising instructions which when executed on a computer perform any of the methods of Example Embodiments El to E27.

[0334] Example Embodiment E31. A computer program product comprising computer program, the computer program comprising instructions which when executed on a computer perform any of the methods of Example Embodiments El to E27.

[0335] Example Embodiment E32. A non-transitory computer readable medium storing instructions which when executed by a computer perform any of the methods of Example Embodiments El to E27.

[0336] Group F Example Embodiments

[0337] Example Embodiment Fl. A user equipment for mobile-integrated Access and Backhaul (mlAB), the UE comprising: processing circuitry configured to perform any of the steps of any of the Group A and C Example Embodiments; and power supply circuitry configured to supply power to the processing circuitry.

[0338] Example Embodiment F2. A network node for indicating access beams for mobile- integrated Access and Backhaul (mlAB), the network node comprising: processing circuitry configured to perform any of the steps of any of the Group B, D, and E Example Embodiments; power supply circuitry configured to supply power to the processing circuitry.

[0339] Example Embodiment F3. A user equipment (UE) for mobile-integrated Access and Backhaul (mlAB), the UE comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry; the processing circuitry being configured to perform any of the steps of any of the Group A and C Example Embodiments; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

Claims

CLAIMS1. A method (1300) by a user equipment, UE (102), for mobile-integrated Access and Backhaul, mlAB, the method comprising: receiving ( 1302) information indicating a beam to be transmitted from a target Distributed Unit (104), DU, during a HO of the UE from a first cell to a second cell, wherein the HO comprises a mlAB Random Access Channel-less, RACH-less, HO.

2. The method of Claim 1, wherein the beam is associated with and / or the information identifies the beam by at least one of: a beam identifier; a Transmission Configuration Indication state identifier; a TCI state configuration; a Synchronization Signal Block identifier; and a Channel State Information-Reference Signal resource identifier.

3. The method of any one of Claims 1 to 2, comprising receiving, 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. The method of any one of Claims 1 to 3, wherein the information is received from a source Centralized Unit, CU (108), via a source DU (110).

5. The method of Claim 4, wherein at least one of: the target DU (104) is a target donor DU, the source DU (110) is a source donor DU, a target CU ( 112) is a target donor CU, and the source CU (108) is a source donor CU.

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

7. The method of any one of Claims 1 to 6, wherein prior to receiving the information, the method comprises: receiving, from the target DU, a plurality of beams; performing at least one measurement procedure based on each of the plurality of beams; andtransmitting, to the source CU, a measurement report comprising at least one value associated with the at least one measurement performed by the UE for at least one of the plurality of beams at the target DU.

8. A method (1400) by a source Centralized Unit, CU (108), for mobile-integrated Access and Backhaul, mlAB, the method comprising: transmitting (1402), to a User Equipment, UE (102), information indicating a beam to be transmitted from a target Distributed Unit, DU (104), during a Handover, HO, of the UE from a first cell to a second cell, wherein the HO comprises a mlAB Random Access Channel-less, RACH-less, HO.

9. The method of Claim 8, wherein the beam is associated with and / or the information identifies the beam by at least one of: a beam identifier; a Transmission Configuration Indication state identifier; a TCI state configuration; a Synchronization Signal Block identifier; and a Channel State Information-Reference Signal resource identifier.

10. The method of any one of Claims 8 to 9, wherein at least one TA value for the beam is transmitted to the UE 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. The method of any one of Claims 8 to 10, wherein the information is transmitted to the UE via a source DU.

12. The method of Claim 11, wherein at least one of: the target DU (104) is a target donor DU, the source DU (110) is a source donor DU, a target CU ( 112) is a target donor CU, and the source CU (108) is a source donor CU.

13. The method of any one of Claims 11 to 12, wherein at least one of the target DU and the source DU is a logical DU.

14. The method of any one of Claims 8 to 13, comprising: determining that the mlAB RACH-less handover is to be triggered towards a target CU.

15. The method of any one of Claims 8 to 14, comprising: prior to transmitting the information to the UE, receiving a measurement report associated with the UE, and wherein the measurement report comprises 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 of Claim 15, 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, 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.

17. The method of Claim 16, comprising transmitting, with the measurement report or the at least one value associated with the measurement report, a suggested beam to be transmitted from the target DU.

18. The method of Claim 17, wherein the suggested beam is selected by the source CU based on at least one of: a value indicating that the suggested beam has a highest channel quality; the suggested beam is associated with a particular PCI; the suggested beam operates in at a particular frequency and / or within a particular frequency range; the suggested beam is associated with a particular cell index; the suggested beam has a strongest Reference Signal Received Power, Reference Signal Received Quality, Signal Interference to Noise Ratio, and / or Received Signal Strength Indicator; the suggested beam is not allocated to another UE; and the suggested beam is allocated to a subset of UEs to which the UE belongs.

19. The method of any one of Claims 17 to 18, wherein the suggested beam is associated with and / or the suggested beam is indicated by at least one of: a beam identifier; a Transmission Configuration Indication state identifier; a TCI state configuration; a Synchronization Signal Block identifier; and a Channel State Information-Reference Signal resource identifier.

20. The method of any one of Claims 16 to 19, wherein:the measurement report or the at least one value associated with the measurement report is transmitted to the target CU in or with a handover request message, and the method comprises receiving, from the target CU, a handover response message comprising the information indicating the beam to be transmitted from the target DU.

21. The method of Claim 20, wherein the response message comprises 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) by atarget Centralized Unit, CU (112), for mobile-integrated Access and Backhaul, mlAB, the method comprising: receiving (1502) from a source CU (108) and / or transmitting to the source CU information indicating a beam to be transmitted from a target Distributed Unit, DU (104), during a handover, HO, of a User Equipment, UE (102), from a first cell to a second cell, wherein the HO comprises an mlAB Random Access Channel-less, RACH-less, HO.

23. The method of Claim 22, wherein the beam is associated with and / or the information identifies the beam by at least one of: a beam identifier; a Transmission Configuration Indication state identifier; a TCI state configuration; a Synchronization Signal Block identifier; and a Channel State Information-Reference Signal resource identifier.

24. The method of any one of Claims 22 to 23, wherein at least one TA value for the beam is transmitted to the UE 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. The method of any one of Claims 22 to 24, wherein at least one of: the target DU (104) is atarget donor DU, a source DU (110) is a source donor DU, the target CU (112) is a target donor CU, and the source CU (108) is a source donor CU.

26. The method of Claim 25, wherein at least one of the target DU and the source DU is a logical DU.

27. The method of any one of Claims 22 to 26, comprising selecting the beam to be transmitted during the HO of the UE.

28. The method of Claim 27, wherein the beam is selected based on at least one of: a value indicating that the beam has a highest channel quality; the beam is associated with a particular PCI; the beam operates in at a particular frequency and / or within a particular frequency range; the beam is associated with a particular cell index; the beam has a strongest Reference Signal Received Power or Reference Signal Received Quality or Signal Interference to Noise Ratio, or Received Signal Strength Indicator; the beam is not allocated to another UE; and the beam is allocated to a subset of UEs to which the UE belongs.

29. The method of any one of Claims 27 to 28, comprising: prior to transmitting the information to the source CU, receiving a measurement report and / or at least one value associated with a measurement report from the source CU, the measurement report and / or the at least one value being associated with at least one measurement performed by the UE for HO from the first cell to the second cell, and wherein the beam is selected based on the measurement report and / or the at least one value associated with the measurement report.

30. The method of Claim 29, wherein: 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 that is associated with the UE; and the information indicating the beam to be transmitted from the target DU is transmitted to the source CU in a handover response message.

31. The method of any one of Claims 29 to 30, comprising receiving, with the measurement report or the at least one value associated with the measurement report, a suggested beam to be used with the target DU.

32. The method of Claim 31, wherein the suggested beam is associated with and / or the suggested beam is indicated by at least one of: a beam identifier; a Transmission Configuration Indication state identifier; a TCI state configuration; a Synchronization Signal Block identifier; and a Channel State Information-Reference Signal resource identifier.

33. The method of 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. The method of any one of Claims 22 to 32, comprising receiving, from the target DU, at least one of: 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.

35. A user equipment, UE (102), for mobile-integrated Access and Backhaul, mlAB, the UE configured to: receive information indicating a beam to be transmitted by a target Distributed Unit, DU (104), during a Handover, HO, of the UE from a first cell to a second cell, wherein the HO comprises a mlAB Random Access Channel-less, RACH-less, HO.

36. The UE of Claim 35, configured to perform any of the methods of Claims 2 to 8.

37. A source Centralized Unit, CU (108), for mobile-integrated Access and Backhaul, mlAB, the source CU configured to: transmit, to a User Equipment, UE (102), information indicating a beam to be transmitted by a target Distributed Unit, DU (104), during a Handover, HO, of the UE from a first cell to a second cell, wherein the HO comprises a mlAB Random Access Channel-less, RACH-less, HO.

38. The source CU of Claim 37, configured to perform any of the methods of Claims 10 to 22.

39. A target Centralized Unit, CU (112), for mobile-integrated Access and Backhaul, mlAB, the target CU configured to: receive from a source CU (108) and / or transmit to the source CU, information indicating a beam to be transmitted by a target Distributed Unit, DU (104), during a handover, HO, of a User Equipment, UE (102), from a first cell to a second cell, wherein the HO comprises a mlAB Random Access Channel-less, RACH-less, HO.

40. The target CU of Claim 39, configured to perform any of the methods of Claims 24 to 35.

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