Methods and apparatuses for enabling performance of early uplink synchronization

Abstract

Embodiments described herein relate to methods and apparatuses for enabling performance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of a UE from a serving network node to a candidate network node A method performed by a first network node comprises transmitting, to the second network node, a first request for a first indication of one or more first dynamic resources to be used by the UE for the early UL synchronization; and receiving, from the second network node, the first indication of the one or more first dynamic resources.

Description

METHODS AND APPARATUSES FOR ENABLING PERFORRMANCE OF EARLYUPLINK SYNCHRONIZATION TECHNICAL FIELD Embodiments described herein relate to methods and apparatuses for enabling performance of early uplink synchronization. In particular, the methods and apparatuses described herein use a dynamic resource allocation. BACKGROUND

[0001] In 3rd Generation Partnership Project (3GPP) Release 18, a work item known as FurtherNew Radio (NR) mobility enhancements is ongoing. This work item includes a technical area entitledLayer 1 / Layer 2 (L1 / L2) based inter-cell mobility. According to the Work Item Description, WID(3GPP TS 38.300, v18.0.0, NR and NG-RAN Overall Description; Stage 2), when the user equipment (UE) moves from the coverage area of one cell to another cell, at some point a serving cell change needs to be performed. Currently, serving cell change is assisted by the UE transmitting Layer 3 (L3) measurements and is done by Radio Resource Control (RRC) signaling triggered Reconfiguration withSynchronization for change of Primary Cell (PCell) and Primary Secondary cell (PSCell), as well asrelease add for Secondary Cells (SCells) when applicable. All cases involve complete L2 (and L1) resets, leading to longer latency, larger overhead and longer interruption time than beam switch mobility. The goal of L1 / L2 based inter-cell mobility (also known as L1 / L2 Triggered Mobility) is toenable a serving cell change, sometimes also known as an L1 / L2 Triggered Mobility (LTM) cell switchor an LTM cell switch procedure, via L1 / L2 signalling, in order to reduce the latency, overhead and interruption time.

[0002] A basic principle with L1 / L2 triggered mobility is that the UE is pre-configured, by thenetwork, with an LTM configuration which includes information such as measurement configurationand an RRC configuration per LTM candidate cell, sometimes also known as an LTM candidate cellconfiguration. Such an LTM candidate cell configuration may be an RRCReconfiguration message orone or more information elements (IEs) / fields / parameters such as CellGroupConfig. The UE performs measurements on LTM candidate cells and beams in those cells, according to the measurement configuration included in the LTM configuration received by the network. The UE transmits L1measurement reports for LTM including L1-Reference Signal Received Power (RSRP) measurementsfor up to four LTM candidate cells and up to four beams in in each cell. When the network (e.g. a basestation (gNB) or a network node distributed unit (gNB-DU)), receives the L1 measurement report forLTM, it may use the content of this report to trigger an LTM cell switch towards one of the LTM candidate cells.

[0003] The network triggers the execution of an LTM cell switch procedure in the UE to one ofthese LTM candidate cells by transmitting an LTM cell switch command Medium Access Control(MAC) Control Element, (MAC CE), to the UE. The LTM cell switch command includes informationsuch as a reference to a LTM candidate cell configuration and an indication of a target beam in the LTM candidate cell. The UE then connects to the beam and switches to the LTM candidate cell configuration.

[0004] The overall procedures for LTM in Rel-18 are described in 3GPP TS 38.300 v 18.0.0,subclause 9.2.3.5, and for the gNB-CU / gNB-DU Architecture in 3GPP TS 38.401 v18.0.0, subclauses 8.2.1.4-8.2.1.6.

[0005] LTM in Rel-18 is limited to intra-gNB (including intra-central unit (CU) intra-DU andintra-CU inter-DU) mobility. In 3GPP Rel-19, a work item on NR Mobility enhancements Phase 4 is about to start, which aims to enhance mobility features, including introducing support for inter-CU LTM according to the objective below.

[0006] “• Specify support for inter-CU Layer 2 Mobility (LTM) [RAN2, RAN3]o Prioritize the case when CU is acting as Master Node (MN) when DC is not configuredo As secondary priority, support the case when NR-DC is configured and CU is acting as SN andMCG is unchangedo As secondary priority, support the case when NR-DC is configured, CU is acting as MN andSCG is unchanged or SCG is released^ Note: The case that LTM is configured in both MCG and SCG is excludedo Specify support for subsequent LTM mobility procedures aiming to avoid RRC configurationbetween cell switches as per Rel-18 LTM^ Coordination with SA3 needed with respect to security key handlingNote: Rel.18 intra-CU LTM procedure is considered as baseline for adding inter-CU support”

[0007] Preamble allocation for Early Uplink Synchronization

[0008] UL pre-sync for LTM, i.e., early Tracking Area (TA) acquisition can be triggered by thenetwork in Rel-18. A Physical Downlink Control Channel (PDCCH) order is transmitted in the sourcecell to the UE and it indicates to the UE to transmit a Physical Random Access Channel (PRACH) preamble in a candidate cell on a preconfigured resource. In order to allow the UE to perform Contention Free Random Access (CFRA) on a candidate cell for early TA acquisition, the candidate gNB-DU assigns preamble index for the UE and transfers to the source gNB-DU over F1 interface before the PDCCH order is sent.

[0009] As being depicted in TS 38.300 v18.0.0, for the random access procedure towards an LTMcandidate cell for early UL TA acquisition, CFRA triggered by a PDCCH order is used. The UE sendsMSG1 towards the cell without monitoring for a response from it. To support UE power ramping, the UE may perform MSG1 retransmission as indicated by the network. SUMMARY

[0010] There currently exist certain challenge(s). Currently preamble allocation is supported overF1 interface for intra-CU LTM. The candidate gNB-DU includes a list of preamble indexes for certain UEs in the UE associated signalings when sending the early uplink, UL, synchronization configuration to the source gNB-DU. However, with a total of 64 preamble indexes for Random Access Channel (RACH) configuration available, the reserved ones might soon be insufficient. This problem becomes even more critical when inter-CU LTM is enabled over the Xn interface.

[0011] Certain aspects of the disclosure and their embodiments may provide solutions to these orother challenges.

[0012] Embodiments described herein relate to methods and apparatuses that enable the sourcenetwork node to request one or more dynamic resources, such as a preamble index for early UL sync, from the candidate network node specifically for a certain UE, in LTM. This mechanism may be used between source gNB-DU and candidate gNB-DU and / or also source NG-RAN node and candidate NG- RAN node.

[0013] Certain embodiments may provide one or more of the following technical advantage(s).The embodiments described herein enable an efficient way to assign one or more dynamic resources (e.g. preamble index) for UL pre-sync between the network nodes for LTM. The intention is to improve the chances of successful handovers between network nodes.

[0014] According to some embodiments there is provided a method, performed by a first networknode, for enabling performance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of a UE from a serving network node to a second network node. The method comprises transmitting, to the second network node, a first request for a first indication of one or more first dynamic resources to be used by the UE for the early UL synchronization; and receiving, from the second network node, the first indication of the one or more first dynamic resources.

[0015] According to some embodiments there is provided a method, performed by a secondnetwork node, for enabling performance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of UE from a serving network node to the second network node. The method comprises receiving, from a first network node, a first request for a first indication of one or more first dynamic resources to be used by the UE for the early UL synchronization; and transmitting, to the first network node, the first indication of the one or more first dynamic resources.

[0016] According to some embodiments there is provided a method performed by a thirdnetwork node, for enabling performance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of UE from the third network node to a second network node. The method comprises receiving, from a first network node, a first indication ofone or more first dynamic resources to be used by the UE for the early UL synchronization; and transmitting, to the user equipment, the first indication of the one or more first dynamic resources.

[0017] According to some embodiments there is provided a method performed by a userequipment for enabling performance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the UE from a serving network node to a candidate network node. The method comprises receiving, from the serving network node, a first indication of one or morefirst dynamic resources for utilizing in performing the early uplink synchronization; receiving, from theserving network node, a second indication of one or more updated dynamic resources; and utilizing the one or more updated dynamic resources to perform the early uplink synchronization.

[0018] According to some embodiments there is provided a first network node for enablingperformance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of a UE from a serving network node to a second network node. The first network node comprises processing circuitry and a memory, the memory containing instructions executable by the processing circuitry whereby the first network node is operable to: transmit, to the second network node, a first request for a first indication of one or more first dynamic resources to be used by the UE for the early UL synchronization; and receive, from the second network node, the first indication of the one or more first dynamic resources.

[0019] According to some embodiments there is provided a second network node, for enablingperformance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of UE from a serving network node to the second network node. The second network node comprises processing circuitry and a memory, the memory containing instructions executable by the processing circuitry whereby the second network node is operable to: receive, from a first network node, a first request for a first indication of one or more first dynamic resources to be used by the UE for the early UL synchronization; and transmit, to the first network node, the first indication of the one or more first dynamic resources.

[0020] According to some embodiments there is provided a third network node, for enablingperformance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of UE from the third network node to a second network node. The third network node comprises processing circuitry and a memory, the memory containing instructions executable by the processing circuitry whereby the third network node is operable to: receive, from a first network node, a first indication of one or more first dynamic resources to be used by the UE for the early UL synchronization; and transmit, to the user equipment, the first indication of the one or more first dynamic resources.

[0021] According to some embodiments there is provided a user equipment for enablingperformance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the UE from a serving network node to a candidate network node. The user equipmentcomprises processing circuitry and a memory, the memory containing instructions executable by the processing circuitry whereby the user equipment is operable to: receive, from the serving network node, a first indication of one or more first dynamic resources for utilizing in performing the early uplink synchronization; receive, from the serving network node, a second indication of one or more updated dynamic resources; and utilize the one or more updated dynamic resources to perform the early uplink synchronization.

[0022] According to some embodiments there is provided a computer program, comprisinginstructions which, when executed on at least one processor, cause the at least one processor to carry out any of the methods described above.

[0023] According to some embodiments there is provided a computer-readable mediumcomprising instructions that, when executed on at least one processor, cause the at least one processor to perform any of the methods described above.

[0024] According to some embodiments there is provided a computer program productcomprising non transitory computer readable media having stored thereon a computer program as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] For a better understanding of the embodiments of the present disclosure, and to show howit may be put into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0026] Fig. 1 illustrates a system structure including the entities involved in embodimentsdescribed herein;

[0027] ig. 2 is a flow chart illustrating a method in accordance with some embodiments;

[0028] Fig. 3 is a flow chart illustrating a method in accordance with some embodiments;

[0029] Fig. 4 is a flow chart illustrating a method in accordance with some embodiments;

[0030] Fig. 5 is a flow chart illustrating a method in accordance with some embodiments;

[0031] Fig. 6 illustrates an example of a message sequence chart in an example implementationof the methods of Figures 2 to 5.

[0032] Fig. 7 illustrates an example of a message sequence chart in an example implementationof the methods of Figure 2, 3 and 4.

[0033] Fig. 8 shows an example of a communication system in accordance with someembodiments;

[0034] Fig. 9 shows a UE in accordance with some embodiments;

[0035] Fig. 10 shows a network node in accordance with some embodiments; and

[0036] Fig. 11 is a block diagram illustrating a virtualization environment in which functionsimplemented by some embodiments may be virtualized.DESCRIPTION

[0037] Some of the embodiments contemplated herein will now be described more fully withreference 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.

[0038] The text refers to the term “L1 / L2 based inter-cell mobility” as used in the Work ItemDescription in 3GPP, though it interchangeably also uses the terms L1 / L2 mobility, L1-mobility, L1 based mobility, L1 / L2-centric inter-cell mobility, L1 / L2 inter-cell mobility L1 / L2-Triggered Mobility, Lower-layer triggered Mobility or LTM. The basic principle is that the UE normally receives a lower layer signaling from the network indicating to the UE a change (or switch or activation) of its serving cell (e.g. change of PCell, from a source to a target PCell), wherein a lower layer signaling is a message / signaling of a lower layer protocol, which sometimes may be referred as a L1 / L2 inter-cell mobilityexecution command or LTM cell switch command. The change of serving cell (e.g. change of PCell)may also lead to a change in Scell(s) for the same cell group e.g. in case the command triggers the UE to change to another cell group configuration of the same type (e.g. another Master Cell Group (MCG) configuration). Before the UE receives the LTM cell switch command, the UE is configured by the network with one or more LTM candidate cell configurations (e.g. reception of an RRC Reconfiguration message, with at least one LTM candidate cell configuration) A LTM candidate cell configuration may include parameters in the IE CellGroupConfig for an LTM candidate cell and / or an embedded RRC Reconfiguration for an LTM candidate cell.

[0039] The term LTM cell switch procedure refers to the process of a UE switching (or changing)its cell from a source cell to a target cell (which may be called here an LTM candidate cell or a neighbourcell), using L1 / L2-triggered mobility (LTM). In the context of L1 / L2-triggered mobility (LTM), anLTM cell switch procedure may sometimes also be known as L1 / L2 based inter-cell mobility execution, LTM execution, dynamic switch, LTM switch, (LTM) cell switch, (LTM) serving cell change or (LTM) cell change. In the context of the invention, switching to the LTM candidate cell configuration comprises the UE considering that an LTM candidate cell becomes its new special cell (SpCell) e.g.Primary Cell (PCell) in case of LTM being configured for a Master Cell Group (MCG) and / or PrimarySecondary Cell (PSCell) in case of LTM being configured for a Secondary Cell Group (SCG); or,changing its SpCell from the current PCell to an LTM candidate cell.

[0040] Even if the term switch or change of cells is used, that may comprise a switch or changeof a whole cell group configuration, which includes a change in the SpCell (e.g. change of PCell,or change of PSCell) and a change in SCells of the cell group (e.g. addition, modification and / or release of one or more SCells).

[0041] An LTM cell switch procedure may be triggered in the UE by reception of a LTM cellswitch command, or alternatively, triggered by some other event, such as a condition, e,g, a triggeringcondition used for conditional configuration, such as conditional handover, being fulfilled, as a result of recovery from radio link failure or handover failure.

[0042] An inter-CU LTM cell switch procedure may comprise an LTM cell switch procedureresulting in a change of serving cell, e.g. change of SpCell, PCell, PSCell, to an LTM candidate cell controlled by a different gNB than the source gNB or serving gNB of the UE upon reception of the LTM cell switch command. From UE point of view, the actions performed during an inter-CU LTM cell switch procedure may be the same type of actions of an LTM cell switch procedure, but may also include additional actions, such as change of security key.

[0043] A LTM candidate cell may comprise a cell the UE is configured with when configuredwith L1 / L2-triggered mobility. That is a cell the UE can move to in an LTM cell switch procedure. Such cells may also be called candidate cell(s), candidates, mobility candidates, non-serving cells, additional cells, target candidate cell, target candidate, etc. A LTM candidate cell is a cell the UE mayperform measurements on (e.g. Channel State Information (CSI) measurements) so that the UE reportsthese measurements and network may take educated decision on which beam (e.g. TransmissionConfiguration Index (TCI) state) and / or cell the UE is to be switched to. An LTM candidate cell maybe a candidate to be a target PCell or PSCell, or an SCell of a cell group (e.g. MCG SCell or a SCG SCell).

[0044] Embodiments described herein refer to at least one LTM candidate cell configuration andthat the UE has received at least one LTM candidate cell configuration. This is also sometimes referred to as a configuration of a LTM candidate cell, which may be an RRC configuration, such as encapsulated in an RRC Reconfiguration message, that the UE receives when being configured with L1 / L2-Triggered Mobility. A LTM candidate cell configuration comprises the configuration which the UE needs to start to operate accordingly when it performs an LTM cell switch procedure to that LTM candidate cell e.g. upon reception of the LTM cell switch command indicating the UE to perform aLTM cell switch procedure to that LTM candidate cell, which becomes the target cell and the current(new) SpCell, or an SCell in a serving frequency. The LTM candidate cell configuration comprises parameters of a serving cell (or multiple serving cells, such as a cell group), comprising one or more of the groups of parameters, such as an RRCReconfiguration message an IE CellGroupConfig or an IE SpCellConfig (or the IE SCellConfig, in the case of a Secondary Cell). A LTM candidate cell configuration may in one example comprise one or more of: i) the PCell configuration and one or more SCell configuration(s) of a Master Cell Group (MCG); i) the PSCell configuration and one or more SCell configuration(s) of a secondary Cell Group (SCG). The terms (LTM) candidate configuration, LTM configuration, (LTM) candidate target cell configuration, (LTM) target candidate (cell) configuration may be used interchangeably when referring to LTM candidate cell configuration. An LTM candidate cell configuration is associated with an identifier which is used in the signaling when referring to a certain LTM candidate cell configuration, such as when the UE receives the LTM candidate cell configuration and when the UE receives an LTM cell switch command indicating theUE to perform a LTM cell switch procedure to that LTM candidate cell. This identifier is sometimes known as the LTM candidate cell configuration identity or LTM candidate configuration index (or similar).

[0045] The actual LTM candidate cell configuration and its exact content and / or structure of thisIE and / or embedded message may be called an RRC model for the candidate configuration, or simply RRC model. An LTM candidate cell configuration comprises the configuration which the UE needs to operate accordingly when it performs (executes) L1 / L2 based inter-cell mobility execution to a LTMcandidate cell, upon reception of the lower layer signaling (MAC CE) indicating a L1 / L2 based inter-cell mobility to a LTM candidate cell (which becomes the target cell and the current (new) PCell, or an SCell in a serving frequency), or upon reception of the lower layer signaling (MAC CE) indicating a L1 / L2 based inter-cell mobility to an LTM candidate cell configuration indicated with a candidate configuration index (sometimes also denoted candidate configuration ID). The UE may be configured with multiple LTM candidate cell configurations, so a Candidate DU generates and sends to the CU multiple configuration(s). The actual LTM candidate cell configuration the UE receives during the LTM configuration may be a delta signaling to be applied on top of a reference configuration, so that the actual configuration the UE is to use in the candidate cell upon LTM cell switch is the combination of the LTM candidate cell configuration and the reference configuration (e.g. separately signaled by the network to the UE).

[0046] Embodiments described herein refer to dynamic resource(s). In the context ofembodiments described herein, a dynamic resource for LTM may be a resource which is allocated and configured for a short period of time, for a certain UE or for a set of UEs. One example of dynamic resource for LTM is a preamble index used at transmission of random access (RA) preambles, e.g. to be used for early TA acquisition, sometimes known as early UL sync. Other examples of dynamic resource may be: ^SCell activation / deactivation indication(s)^ CSI measurement configuration activation / deactivation indication(s)^ TCI state(s) indication(s)^ Spatial relation indication^ RS indication^ UL grant^ PUCCH configuration^ PRACH configuration to be used e.g. PRACH preamble, preamble set, preamble group out ofa set in the RRC configuration; ^DL BWP ID^ UL BWP ID^ C-RNTI out of a set^ Timer value^ Timing advance information^ Configured grant configuration^ PUCCH for SR configuration^ Scell configuration indication^ Any dynamic information which may need to be activatedAny information to change state

[0047] Figure 1 illustrates a system structure including the entities that may be involved inembodiments described herein. The User Equipment (UE) 101 is a wireless terminal, such as a cellular smartphone, sometimes connected to the first network node 102 over a wireless interface 105. The UE is sometimes connected to the second network node 103 over the wireless interface 106 and sometimes to the third network node 104 over the wireless interface 107.

[0048] The first network node 102 may sometimes be referred to as a serving gNB or servingnetwork node, or in a distributed CU / DU Radio Access Network (RAN) architecture, referred to as aserving CU, gNB-CU, CU-CP or similar. The second network node 1003 may in the context of mobility sometimes be referred to as a candidate gNB, target gNB, or in a distributed CU / DU RAN architecture, referred to as a candidate DU, target DU or gNB-DU or similar. The second network node controls a second cell 110, which sometimes, in the context of mobility, is referred to as a neighbor cell, a candidate cell or an LTM candidate cell.

[0049] In some scenarios, such as in a distributed CU / DU RAN architecture, there is a thirdnetwork node 104, which sometimes may be referred to as a serving DU, source DU, or gNB-DU or similar.

[0050] The first network node is connected to the second network node over an interface 1008,which may sometimes be a F1 or Xn type of interface. In some scenarios, the first network node is connected to the third network node over an interface 109, which may be an F1 type of interface.

[0051] In some examples there is provided a first method for a first network node, such as aserving gNB or a serving CU, to handle dynamic resource allocation for a UE, for intra-CU and / or inter-CU LTM. The method comprises one or more of the following steps:^ transmitting, to the second network node, such as a candidate gNB or a candidate DU, a requestmessage to ask for one or more dynamic resources. ^receiving, from the second network node, a response message including one or more dynamicresource(s) for the UE(s). ^in one example the request message is existing F1AP UE Context Setup Request, F1AP UEContext Modification Request, XnAP Handover Request message and etc. ^in another example the request is a new message, e.g., Dynamic Resource Request. This newmessage can be UE associated or non-UE associated signaling.^ in one example the response message is existing F1AP UE Context Setup Response, F1AP UEContext Modification Response, XnAP Handover Request Acknowledge message and etc. ^in another example the response is a new message, e.g., Dynamic Resource Response. This newmessage can be UE associated or non-UE associated signaling.

[0052] In some examples, the first method described above further comprises the first networknode receiving, from the second network node, such as a candidate gNB or a candidate DU, a requestto remove or update dynamic resource(s), for the UE. The first method may further comprises one ormore of the following steps: ^receiving, from the second network node, a request message to remove one or more dynamicresource(s) which have been received in the previous message. ^receiving, from the second network node, a request message to update one or more dynamicresource(s) which have been received in the previous message. ^transmitting, to the second network node, a response message to acknowledge the removal orupdate of dynamic resource can be done. ^transmitting, to the second network node, a response message to indicate the change of dynamicresource fails, due to e.g., the dynamic resource has been sent to the UE already. ^in one example the request message is existing F1AP gNB-DU Configuration Update, XnAPNG-RAN Node Configuration Update message and etc. ^in another example the request is sent in a new message, e.g., Dynamic Resource Update. Thisnew message can be UE associated or non-UE associated signaling. ^in one example the response message is existing F1AP gNB-DU Configuration UpdateAcknowledge, XnAP NG-RAN Node Configuration Update Acknowledge message and etc. ^in another example the request is sent in a new message, e.g., Dynamic Resource UpdateAcknowledge. This new message can be UE associated or non-UE associated signaling.

[0053] In some examples there is provided a second method for a first network node, such as aserving gNB or a serving CU, to inform the third network node, such as a serving DU, about dynamicresource allocation for a UE, for intra-CU and / or inter-CU LTM. The second method comprises one ormore of the following steps: ^transmitting, to the third network node, a message to inform about the dynamic resource(s), tobe allocated to the UE(s) for early UL sync. ^receiving, from the third network node, an acknowledge message indicating that theinformation is received. ^in one example the request message is existing F1AP UE Context Setup Request, F1AP UEContext Modification Request, and etc.^ in another example the request is a new message, e.g., Dynamic Resource Request. This newmessage can be UE associated or non-UE associated signaling. ^in one example the response message is existing F1AP UE Context Setup Response, F1AP UEContext Modification Response, and etc. ^in another example the response is a new message, e.g., Dynamic Resource Response. This newmessage can be UE associated or non-UE associated signaling.

[0054] In some examples, the second method described above further comprises, the first networknode transmitting, to the third network node, such as a serving DU, a message to remove or updatedynamic resource(s), for the UE. The second method may further comprise one or more of the followingsteps: ^transmitting, to the third network node, a message to remove one or more dynamic resource(s)which have been sent in the previous message. ^receiving, from the third network node, an acknowledge message including the indication ofone or more dynamic resource(s) for the UE which have been updated. ^in one example the request message is existing F1AP gNB-CU Configuration Update, and etc.^ in another example the request is sent in a new message, e.g., Dynamic Resource Update. Thisnew message can be UE associated or non-UE associated signaling. ^in one example the response message is existing F1AP gNB-CU Configuration UpdateAcknowledge, and etc. ^in another example the request is a new message, e.g., Dynamic Resource UpdateAcknowledge. This new message can be UE associated or non-UE associated signaling.

[0055] In some examples, in the first method, the signalling between the source DU and acandidate DU is via a direct interface between DUs.

[0056] In some examples, in the first method or the second method, the dynamic resource is apreamble index for early UL sync.

[0057] In some examples of the first method or the second method, the message transmitted to thefirst network node and the message received from the second network node includes one or moreidentifier of one or more UEs.

[0058] In the case that the message used to signal the preamble (or other dynamic resource) is anon-UE associated message then there may be a mapping between the preambles (or other dynamic resource) listed and the UE(s). For that there may be an identifier of the UE included. In one example this could be the gNB-DU UE F1AP ID together with the LTM Configuration ID.

[0059] In some examples, there is provided a third method at a second network node, such as acandidate gNB or a candidate DU, to handle the dynamic resource for a UE, e.g., for the UE. The third method comprises one or more of the following steps: ^receiving, from the first network node, a request message to ask for one or more dynamicresource(s) to be allocated to the UE(s). ^transmitting, to the first network node, a response message including one or more dynamicresource(s) ) for the UE(s).

[0060] In some examples, the third method comprises the second network node transmitting, tothe first network node, a request to remove or update dynamic resource(s), for the UE. The third method may comprise one or more of the following steps: ^transmitting, to the first network node, a message to remove one or more dynamic resource(s)which have been sent in the previous message. ^receiving, from the first network node, an acknowledge message including the indication of oneor more dynamic resource(s) for the UE which have been updated.

[0061] In some examples, in the third method, the dynamic resource is a preamble index forearly UL sync.

[0062] In some examples, in the third method, wherein the message received from the firstnetwork node and the message transmitted from the second network node include one or more identifier of one or more UEs.

[0063] In some examples, there is provided a fourth method, at a third network node, such as aserving DU, to handle the dynamic resource(s), for the UE. The fourth method comprises one or more of the following steps: ^receiving, from the first network node, a message to inform about the dynamic resourceallocation, to be allocated to the UE(s). ^transmitting, to the first network node, a response message to acknowledge the reception of theabove information.

[0064] In some examples, the fourth method comprises third network node receiving, from thefirst network node, a request to remove or update dynamic resource(s), for the UE. For example, the fourth method may comprise one or more of: ^receiving, from the first network node, a message to remove one or more preamble index(es)which have been sent in the previous message. ^transmitting, to the first network node, an acknowledge message including the indication of oneor more dynamic resource for the UE which have been updated.

[0065] In some examples, the dynamic resource is a preamble index for early UL sync.

[0066] In some examples, in the fourth method, the message received from the first network nodeand the message transmitted from the third network node include one or more identifier of one ormore UEs.

[0067] In some examples, there is provided a fifth method at a User Equipment (UE), to performearly TA acquisition. The fifth method comprises one or more of the following steps:^ receiving, from a first network node (serving gNB) or a third network node (serving DU), afirst lower layer signalling transmit a preamble for UL pre-sync to an LTM candidate cell using an indicated dynamic resource. ^receiving, from a first network node (serving gNB) or a third network node (serving DU), asecond lower layer signalling to update a preamble for UL pre-sync to the LTM candidate cell. ^transmitting, in the LTM candidate cell, a preamble for UL pre-sync using the indicateddynamic resource.

[0068] In some examples, in the fifth method, the dynamic resource is a preamble index for earlyUL sync.

[0069] In some examples, in the fifth method, the UE releases the stored dynamic resources andstarts to use the ones received within the second lower layer signalling. In another example, the UEmay release all the stored dynamic resources, regardless on which one has been received within the second lower layer signalling. In some examples, the UE releases only the stored dynamic resourcewith are the same as the one received within the second lower layer signalling. For instance, if the lower layer signalling includes Resource A, the UE releases only Resource A from its memory and start using Resource A received within the second lower layer signalling.

[0070] In some examples, in the fifth method the lower layer signalling is a PDCCH order.

[0071] Figure 2 illustrates a method in accordance with particular embodiments. The method ofFigure 2 may be performed by a UE or wireless device (e.g. the UE 812 or UE 900 as described laterwith reference to Figures 8 and 9 respectively). The method of Figure 2 may be for enablingperformance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the UE from a serving network node to a candidate network node. The method begins at step 202 with receiving, from the serving network node, a first indication of one or more first dynamic resources for utilizing in performing the early uplink synchronization. In step 204 the method comprises receiving, from the serving network node, a second indication of one or more updated dynamic resources. In step 206 the method comprises utilizing the one or more updated dynamic resources to perform the early uplink synchronization.

[0072] It will be appreciated that the serving network node may comprise one of: a servingdistributed unit, DU, and a serving base station (gNB). The candidate network node may comprise oneof: a candidate distributed unit, DU and a candidate base station. In other words, the LTM cell switchmay be one of: intra-CU, inter CU or inter-gNB.

[0073] As described above, the one or more first dynamic resources (and / or updated dynamicresources) may comprise one or more of: Secondary Cell, SCell, activation / deactivation indication(s) Channel State Information, CSI, measurement configuration activation / deactivation indication(s) Transmission Configuration Indication, TCI, state(s) indication(s) Spatial relation indication Reference Signal, RS, indication Uplink, UL, grant Physical Uplink Control Channel, PUCCH, configuration Physical Random Access Channel, PRACH, configuration to be used; Downlink, DL, bandwidth part, BWP, identifier, ID Uplink, UL, bandwidth part, BWP, identifier, ID Cell, Radio Number Temporary Identifier, C-RNTI, out of a set Timer value Timing advance information Configured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configuration Scell configuration indication; and a preamble index.

[0074] The first indication of the one or more first dynamic resources and / or the second indicationof the one or more updated dynamic resources may be received on lower layer signalling.

[0075] In some examples, the second indication of one or more updated dynamic resourcesupdates a subset of the one or more first dynamic resources. The method of Figure 2 may then furthercomprise utilizing the one or more updated dynamic resources and one or more of the first dynamic resources not updated by the second indication to perform the early uplink synchronization. In otherexamples, the method of Figure 2 may then further comprise refraining from utilizing the one or moreof the first dynamic resources not updated by second indication to perform the early uplink synchronization.

[0076] For example, the one or more first dynamic resources may comprise Resource A, ResourceB and Resource C. The updated dynamic resources may comprise Resource A’ and Resource B’ which updates resources Resource A and Resource B. The UE may in some examples, there use Resource A’, Resource B’ and Resource C to perform the early UL synchronization. In other examples, the UE mayrefrain from using Resource C, and may only use Resource A’ and Resource B’ to perform the early UL synchronization.

[0077] Figure 3 illustrates a method in accordance with particular embodiments. The method 3may be performed by a first network node (e.g. the network node 810 or network node 1000 as describedlater with reference to Figures 8 and 10 respectively). The method may be for enabling performance ofearly uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of a UE from a serving network node to a second network node.

[0078] The method begins at step 302 with transmitting, to the second network node, a first requestfor a first indication of one or more first dynamic resources to be used by the UE for the early UL synchronization. In step 304 the method comprises receiving, from the second network node, the first indication of the one or more first dynamic resources.

[0079] As described above, LTM cell switch may be one of: intra-CU, inter CU or inter-gNB. Ins some examples, the first network node (e.g. where the first network node comprises a gNB comprisesthe serving network node). In other examples, a serving distributed unit, DU, connected to the firstnetwork node (e.g. where the first network node comprises a CU) comprises the serving network node. The second network node may comprise one of: a candidate distributed unit, DU and a candidate basestation (e.g. gNB).

[0080] In some examples, the method of Figure 3 further comprises, responsive to receiving thefirst indication of the one or more first dynamic resources, forwarding the first indication to a thirdnetwork node (e.g. the DU serving the UE) or to the UE.

[0081] In some examples, the method of Figure 3 further comprises receiving, from the secondnetwork node, a second indication of one or more updated dynamic resources. The second indication of one or more updated dynamic resources may adjusts, removes or adds to the one or more first dynamic resources. For example, adjustment may comprise changing Resource A to Resource A’. Removal may comprise removing Resource A. Adding may comprise adding new resource, e.g. Resource B.

[0082] In some examples, the method of Figure 3 further comprises, responsive to receiving thesecond indication, forwarding the second indication to the third network node or the UE.

[0083] As describes above the one or more first dynamic resources (or the one or more updateddynamic resources) comprises one or more of: Secondary Cell, SCell, activation / deactivation indication(s) Channel State Information, CSI, measurement configuration activation / deactivation indication(s) Transmission Configuration Indication, TCI, state(s) indication(s) Spatial relation indication Reference Signal, RS, indication Uplink, UL, grantPhysical Uplink Control Channel, PUCCH, configuration Physical Random Access Channel, PRACH, configuration to be used; Downlink, DL, bandwidth part, BWP, identifier, ID Uplink, UL, bandwidth part, BWP, identifier, ID Cell, Radio Number Temporary Identifier, C-RNTI, out of a set Timer value Timing advance information Configured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configuration Scell configuration indication; and a preamble index.

[0084] In some examples of Figure 3 the first request comprises a UE identifier of the UEassociated with the one or more first dynamic resources.

[0085] In some examples of Figure 3 the method further comprises, responsive to receiving thesecond indication, transmitting a response message to indicate the update to the one or more first dynamic resource has failed, e.g. due to the one or more first dynamic resources having been sent to the UE already.

[0086] Figure 4 illustrates a method in accordance with particular embodiments. The method ofFigure 4 may be performed by a second network node (e.g. the network node 810 or network node 1000as described later with reference to Figures 8 and 10 respectively). The method may be for enablingperformance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of a UE from a serving network node to the second network node.

[0087] In step 402 the method comprises receiving, from a first network node, a first request fora first indication of one or more first dynamic resources to be used by the UE for the early ULsynchronization. In step 404 the method comprises transmitting, to the first network node, the firstindication of the one or more first dynamic resources. Step 402 corresponds to step 302 and step 404 corresponds to step 304.

[0088] The first network node may comprise one of: the serving network node, a serving centralunit, CU, and a serving base station (gNB). The second network node comprises one of: a candidate distributed unit, DU and a candidate base station (gNB). The LTM cell switch may be one of: intra-CU, inter-CU or inter-gNB.

[0089] In some examples, the method of Figure 4 further comprises, receiving from the UEinitiation of the early UL synchronization utilizing the one or more first dynamic resources. Forexample, the UE may transmit a preamble utilizing the indication of a preamble index in the one ormore first dynamic resources.

[0090] In some examples, the method of Figure 4 further comprises transmitting, to the firstnetwork node, a second indication of one or more updated dynamic resources. The second indication of one or more updated dynamic resources may adjusts, removes or adds to the one or more first dynamicresources (e.g. as described above with reference to Figure 3).

[0091] In some examples, responsive to transmitting the second indication, the method of Figure4 further comprises receiving from the UE, initiation of the early UL synchronization utilizing the oneor more updated dynamic resources. For example, the UE may transmit a preamble utilizing theindication of a preamble index in the one or more updated dynamic resources.

[0092] As described above, the one or more first dynamic resources (and / or one or more updateddynamic resources) comprises one or more of:Secondary Cell, SCell, activation / deactivation indication(s) Channel State Information, CSI, measurement configuration activation / deactivation indication(s) Transmission Configuration Indication, TCI, state(s) indication(s) Spatial relation indication Reference Signal, RS, indication Uplink, UL, grant Physical Uplink Control Channel, PUCCH, configuration Physical Random Access Channel, PRACH, configuration to be used; Downlink, DL, bandwidth part, BWP, identifier, ID Uplink, UL, bandwidth part, BWP, identifier, ID Cell, Radio Number Temporary Identifier, C-RNTI, out of a set Timer value Timing advance information Configured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configuration Scell configuration indication; and a preamble index.

[0093] Figure 5 illustrates a method in accordance with particular embodiments. The method ofFigure 5 may be performed by a third network node (e.g. the network node 810 or network node 1000as described later with reference to Figures 8 and 10 respectively). The method may be for enablingperformance of early uplink, UL, synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cellswitch of a UE from the third network node to a second network node. In step 502 the method comprisesreceiving, from a first network node, a first indication of one or more first dynamic resources to be used by the UE for the early UL synchronization. In step 504 the method comprises transmitting, to the userequipment, the first indication of the one or more first dynamic resources.

[0094] The third network node may comprise a serving distributed unit, DU. The first networknode may comprise a serving central unit, CU. The second network node may comprise a candidate DU.

[0095] In some examples, the method of Figure 5 further comprises receiving, from the firstnetwork node, a second indication of one or more updated dynamic resources to be used by the UE for the early UL synchronization. The method may then further comprise transmitting, to the user equipment, the second indication.

[0096] The one or more first dynamic resources (and / or one or more updated dynamic resources)comprises one or more of: Secondary Cell, SCell, activation / deactivation indication(s) Channel State Information, CSI, measurement configuration activation / deactivation indication(s) Transmission Configuration Indication, TCI, state(s) indication(s) Spatial relation indication Reference Signal, RS, indication Uplink, UL, grant Physical Uplink Control Channel, PUCCH, configuration Physical Random Access Channel, PRACH, configuration to be used; Downlink, DL, bandwidth part, BWP, identifier, ID Uplink, UL, bandwidth part, BWP, identifier, ID Cell, Radio Number Temporary Identifier, C-RNTI, out of a set Timer value Timing advance information Configured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configuration Scell configuration indication; and a preamble index.

[0097] Figure 6 illustrates an example of a message sequence chart in an example implementationof the methods of Figures 2 to 5.

[0098] In this example, the first network node is a CU, the second network node is a candidateDU and the third network node is a serving DU.

[0099] Main steps in this example are as follows:Step 601. The serving DU decides to configure LTM for the UE including at least one LTMcandidate cell, and transmits a request to the candidate DU.Step 602. The candidate DU generates at least one LTM candidate cell configuration and an earlyUL sync RACH configuration.Step 603. The candidate DU responds to the CU and includes the generated information in theresponse message.Steps 604-605. The CU informs the serving DU about the early UL sync RACH configuration foreach LTM candidate cell. Steps 606-607. The CU provides the UE with an LTM configuration, including at least one LTM candidate configuration and the early UL sync RACH configuration, for each candidate cell.Step 608. The serving DU determines to trigger early UL sync (also known as UL pre-sync) foran LTM candidate cell for the UE.Step 609. The serving DU transmits, to the CU, a message to request dynamic resources in thecandidate DU and includes a request for preamble index in the message.Step 610. The CU forwards the request to the candidate DU. (This step may be considered tocomprise an example implementation of step 302 of Figure 3 or step 402 of Figure 4)Step 611. The candidate DU allocates preamble index(es) for early UL sync for the UE andresponds to the CU. This step may be considered to comprise an example implementation of step 304 of Figure 3 or step 404 of Figure 4)Step 612. The CU forwards the response to the serving DU. This step may be considered tocomprise an example implementation of step 502 of Figure 5Step 613. The serving DU transmits a PDCCH order to request the UE to transmit a preamble tothe indicated LTM candidate cell and using the indicated preamble index (the same preamble index allocated in step 11). This step corresponds to step 202 of Figure 2 orstep 504 of Figure 5.Step 614. The UE transmits an RA preamble using the indicated preamble index in the LTMcandidate cell.Steps 615-616. The candidate DU calculates a timing advance (TA) based on the receivedpreamble and transmits the TA to the serving DU via the CU.

[0100] Figure 7 illustrates an example of a message sequence chart in an example implementationof the methods of Figure 2, 3 and 4.

[0101] In this example, the first network node is a serving gNB, and the second network node isa candidate gNB.

[0102] Main steps in this example are as follows:Step 701. The serving gNB decides to configure LTM for the UE including at least one LTMcandidate cell, and transmits a request to the candidate gNB.Step 702. The candidate gNB generates at least one LTM candidate cell configuration and anearly UL sync RACH configuration.Step 703. The candidate gNB responds to the serving gNB and includes the generatedinformation in the response message.Steps 704-705. The serving gNB provides the UE with an LTM configuration, including at leastone LTM candidate configuration and the early UL sync RACH configuration, for each candidate cell.Step 706. The serving gNB determines to trigger early UL sync (also known as UL pre-sync) foran LTM candidate cell for the UE.Step 707. The serving gNB transmits, to the candidate gNB, a message to request dynamicresources in the candidate gNB and includes a request for preamble index in the message. This step may be considered to comprise an example implementation of step302 of Figure 3 or Step 402 of Figure 4.Step 708. The candidate gNB allocates preamble index(es) for early UL sync for the UE andresponds to the serving gNB. This step may be considered to comprise an exampleimplementation of step 304 of Figure 3 or step 404 of Figure 4.Step 709. The serving gNB transmits a PDCCH order to request the UE to transmit a preamble tothe indicated LTM candidate cell and using the indicated preamble index (the same preamble index allocated in step 708). This step comprises an example implementationof step 202 of Figure 2.Step 710. The UE transmits an RA preamble using the indicated preamble index in the LTMcandidate cell.Step 711. The candidate gNB calculates a timing advance (TA) based on the received preambleand transmits the TA to the serving gNB. Technical Specification Impact Below illustrates an example implementation in the 3GPP F1AP specification, TS 38.473 v18.0.0, and XnAP specification, TS 38.423 v18.0.0, is illustrated for examples of the invention. (This entire section is considered new according to embodiments described herein) for TS 38.473: This message is sent by the gNB-DU to request for dynamic resource to be allocated for the UE.Direction: gNB-DU ^ gNB-CUIE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit y Message Type M 9.3.1.1 YES ignoregNB-CU UE F1AP M 9.3.1.4 YES rejectID gNB-DU UEM 9.3.1.5 YES rejectF1AP ID Cell ID M NR CGI YES reject9.3.1.12LTM Dynamic0..1 YES ignoreResource Request >Request forM ENUMERA- Preamble Index TED (true, ...) This message is sent by the gNB-CU to request for dynamic resource to be allocated for the UE.Direction: gNB-CU ^ gNB-DUIE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit y Message Type M 9.3.1.1 YES ignoregNB-CU UE F1AP M 9.3.1.4 YES rejectID gNB-DU UEM 9.3.1.5 YES rejectF1AP ID Cell ID M NR CGI YES reject9.3.1.12 LTM Dynamic0..1 YES ignoreResource Request >Request forM ENUMERA- Preamble Index TED (true, ...) This message is sent by the gNB-DU to transfer dynamic resource to be allocated for the UE.Direction: gNB-DU ^ gNB-CUIE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit y Message Type M 9.3.1.1 YES ignoregNB-CU UE F1AP M 9.3.1.4 YES rejectID gNB-DU UEM 9.3.1.5 YES rejectF1AP ID Cell ID M NR CGI YES reject9.3.1.12 LTM Dynamic0..1 YES ignoreResource Response >Preamble Index M INTEGER- (0..63) This message is sent by the gNB-CU to transfer dynamic resource to be allocated for the UE.Direction: gNB-CU ^ gNB-DUIE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit yMessage Type M 9.3.1.1 YES ignoregNB-CU UE F1AP M 9.3.1.4 YES rejectID gNB-DU UEM 9.3.1.5 YES rejectF1AP ID Cell ID M NR CGI YES reject9.3.1.12 LTM Dynamic0..1 YES ignoreResource Response >Preamble Index M INTEGER- (0..63) This message is sent by the gNB-DU to update the dynamic resource to be allocated for the UE.Direction: gNB-DU ^ gNB-CUIE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit y Message Type M 9.3.1.1 YES ignoregNB-CU UE F1AP M 9.3.1.4 YES rejectID gNB-DU UEM 9.3.1.5 YES rejectF1AP ID Cell ID M NR CGI YES reject9.3.1.12 LTM Dynamic0..1 YES ignoreResource To Be Updated >Preamble Index M INTEGER- (0..63) This message is sent by the gNB-CU to update the dynamic resource to be allocated for the UE.Direction: gNB-CU ^ gNB-DUIE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit y Message Type M 9.3.1.1 YES ignoregNB-CU UE F1AP M 9.3.1.4 YES rejectID gNB-DU UEM 9.3.1.5 YES rejectF1AP ID Cell ID M NR CGI YES reject9.3.1.12 LTM Dynamic0..1 YES ignoreResource To Be Updated>Preamble Index M INTEGER- (0..63) This message is sent by the gNB-DU to acknowledge the change of dynamic resource to be allocated for the UE.Direction: gNB-DU ^ gNB-CUIE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit y Message Type M 9.3.1.1 YES ignoregNB-CU UE F1AP M 9.3.1.4 YES rejectID gNB-DU UEM 9.3.1.5 YES rejectF1AP ID Cell ID M NR CGI YES reject9.3.1.12 LTM DynamicO ENUMERA YES ignoreResource Updated TED (accepted, rejected, ...) This message is sent by the gNB-CU to acknowledge the change of dynamic resource to be allocated for the UE.Direction: gNB-CU ^ gNB-DUIE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit y Message Type M 9.3.1.1 YES ignoregNB-CU UE F1AP M 9.3.1.4 YES rejectID gNB-DU UEM 9.3.1.5 YES rejectF1AP ID Cell ID M NR CGI YES reject9.3.1.12 LTM DynamicO ENUMERA YES ignoreResource Updated TED (accepted, rejected, ...) 8.2.5 gNB-CU Configuration Update (The additions are shown bold and underlined.) The purpose of the gNB-CU Configuration Update procedure is to update application level configuration data needed for the gNB-DU and gNB-CU to interoperate correctly on the F1 interface. This procedure does not affect existing UE-related contexts, if any. The procedure uses non-UE associated signalling.[Text omitted]If the LTM Dynamic Resource Request IE is included in the GNB-CU CONFIGURATIONUPDATE message the gNB-DU will include if supported LTM Dynamic Resource Response IE inthe GNB-CU CONFIGURATION UPDATE ACKNOWLEDGE message. This message is sent by the gNB-CU to transfer updated information associated to an F1-C interface instance. NOTE: If F1-C signalling transport is shared among several F1-C interface instances, thismessage may transfer updated information associated to several F1-C interface instances.Direction: gNB-CU ^ gNB-DUIE / Group Name Presence Range IE type andSemantics Criticalit Assigned reference description y Criticalit y Message Type M 9.3.1.1 YES rejectTransaction ID M 9.3.1.23 YES rejectText omitted LTM Dynamic0..1 YES ignoreResource Request >Request forM ENUMERAT- Preamble Index ED (true, ...) This message is sent by a gNB-DU to a gNB-CU to acknowledge update of information associated to an F1-C interface instance. NOTE: If F1-C signalling transport is shared among several F1-C interface instance, thismessage may transfer updated information associated to several F1-C interface instances.Direction: gNB-DU ^ gNB-CUIE / Group Name Presence Range IE type andSemantics Criticalit Assigned reference description y Criticalit y Message Type M 9.3.1.1 YES rejectTransaction ID M 9.3.1.23 YES reject[Text omitted] LTM Dynamic0..1 YES ignoreResource Response >Preamble Index M INTEGER- (0..63) >UE AssistantM gNB-CU UE– Identifier F1AP ID 9.3.1.4 >LTMM INTEGERCorresponds to - Configuration ID (1..8) the LTM- CandidateId IE,as defined in TS 38.331 [8].TS 38.423 (This entire section is considered new according to embodiments described herein):This message is sent by the source NG-RAN node to the target NG-RAN node to request for the dynamic resources for a handover.Direction: source NG-RAN node ^ target NG-RAN node.IE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit y Message Type M 9.2.3.1 YES rejectSource NG-RANM NG-RANAllocated atYES rejectnode UE XnAP ID node UE the source reference XnAP ID NG-RAN 9.2.3.16 node Target Cell GlobalM 9.2.3.25 Includes either YES rejectID an E-UTRA CGI or an NR CGI LTM Dynamic0..1 YES ignoreResource Request >Request forM ENUMERA- Preamble Index TED (true, ...) This message is sent by the target NG-RAN node to transfer dynamic resource to be allocated for the UE.Direction: target NG-RAN nodesource NG-RAN node.IE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit y Message Type M 9.2.3.1 YES rejectSource NG-RANM NG-RANAllocated atYES ignorenode UE XnAP ID node UE the source XnAP ID NG-RAN 9.2.3.16 node Target NG-RANM NG-RANAllocated atYES ignorenode UE XnAP ID node UE the target NG- XnAP ID RAN node 9.2.3.16 LTM Dynamic0..1 YES ignoreResource Response >Preamble Index M INTEGER- (0..63)This message is sent by the target NG-RAN node to to update the dynamic resource to be allocatedfor the UE.Direction: target NG-RAN nodesource NG-RAN node.IE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit y Message Type M 9.3.1.1 YES ignoregNB-CU UE F1AP M 9.3.1.4 YES rejectID gNB-DU UEM 9.3.1.5 YES rejectF1AP ID Cell ID M NR CGI YES reject9.3.1.12 LTM Dynamic0..1 YES ignoreResource To Be Updated >Preamble Index M INTEGER- (0..63)This message is sent by the source NG-RAN node to acknowledge the change of dynamic resource tobe allocated for the UE.Direction: source NG-RAN node ^ target NG-RAN node.IE / Group Name Presenc Range IE type andSemantics Critical Assigned e reference description ity Criticalit y Message Type M 9.3.1.1 YES ignoregNB-CU UE F1AP M 9.3.1.4 YES rejectID gNB-DU UEM 9.3.1.5 YES rejectF1AP ID Cell ID M NR CGI YES reject9.3.1.12 LTM DynamicO ENUMERA YES ignoreResource Updated TED (accepted, rejected, ...)8.4.2 NG-RAN node Configuration Update (The additions are shown bold and underlined.)The purpose of the NG-RAN node Configuration Update procedure is to update application level configuration data needed for two NG-RAN nodes to interoperate correctly over the Xn-C interface. NOTE: Update of application level configuration data also applies between two NG-RAN nodesin case the SN (i.e. the gNB) does not broadcast system information other than for radio frame timing and SFN, as specified in the TS 37.340 [8]. How to use this information when this option is used is not explicitly specified. The procedure uses non UE-associated signalling. Text omittedIf the LTM Dynamic Resource Request IE is included in the NG-RAN NODECONFIGURATION UPDATE ACKNOWLEDGE message the NG-RAN node1 shall, ifsupported, include the LTM Dynamic Resource Response IE in the NG-RAN NODECONFIGURATION UPDATE ACKNOWLEDGE message.This message is sent by a NG-RAN node to a neighbouring NG-RAN node to transfer updated information for an Xn-C interface instance.Direction: NG-RAN node1 ^ NG-RAN node2.IE / Group Name Presence Range IE type andSemantics Criticalit Assigned reference description y Criticalit y Message Type M 9.2.3.1 YES rejectText omitted LTM Dynamic0..1 YES ignoreResource Request >Request forM ENUMERAT- Preamble Index ED (true, ...) This message is sent by a neighbouring NG-RAN node to a peer node to acknowledge update of information for a TNL association.Direction:node1.IE / Group Name Presence Range IE type andSemantics Criticalit Assigned reference description y Criticalit y Message Type M 9.2.3.1 YES rejectText omitted LTM Dynamic0..1 YES ignoreResource Response >Preamble Index M INTEGER- (0..63) >UE AssistantM NG-RAN– Identifier node UE XnAP ID 9.2.3.16 >LTMM INTEGERCorresponds to - Configuration ID (1..8) the LTM- CandidateId IE,as defined in TS 38.331 [8].

[0103] Figure 8 shows an example of a communication system 800 in accordance with someembodiments.

[0104] In the example, the communication system 800 includes a telecommunication network 802that includes an access network 804, such as a radio access network (RAN), and a core network 806, which includes one or more core network nodes 808. The access network 804 includes one or more access network nodes, such as network nodes 810a and 810b (one or more of which may be generally referred to as network nodes 810), or any other similar 3rd Generation Partnership Project (3GPP)access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, anetwork node is not necessarily limited to an implementation in which a radio portion and a basebandportion are supplied and integrated by a single vendor. Thus, it will be understood that network nodesinclude disaggregated implementations or portions thereof. For example, in some embodiments, thetelecommunication network 802 includes one or more Open-RAN (ORAN) network nodes. An ORANnetwork node is a node in the telecommunication network 802 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network 802, including one or more network nodes 810 and / or core network nodes 808.

[0105] Examples of an ORAN network node include an open radio unit (O-RU), an opendistributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU-CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designatingsupport of an ORAN specification). The network node may support a specification by, for example,supporting an interface defined by the ORAN specification, such as an A1, F1, W1, E1, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface.Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORANnetwork node may be implemented in a virtualization environment (described further below) in whichone or more network functions are virtualized. For example, the virtualization environment may includean O-Cloud computing platform orchestrated by a Service Management and Orchestration Frameworkvia an O-2 interface defined by the O-RAN Alliance or comparable technologies. The network nodes810 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 812a, 812b, 812c, and 812d (one or more of which may be generally referred to as UEs 812) to the core network 806 over one or more wireless connections.

[0106] Example wireless communications over a wireless connection include transmitting and / orreceiving 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 800 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 800 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0107] The UEs 812 may be any of a wide variety of communication devices, including wirelessdevices arranged, configured, and / or operable to communicate wirelessly with the network nodes 810 and other communication devices. Similarly, the network nodes 810 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 812 and / or with other network nodes or equipment in the telecommunication network 802 to enable and / or provide network access, such aswireless network access, and / or to perform other functions, such as administration in the telecommunication network 802.

[0108] In the depicted example, the core network 806 connects the network nodes 810 to one ormore host computing systems, such as host 816. 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 806 includes one more core network nodes (e.g., core network node 808) 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 thatthe descriptions thereof are generally applicable to the corresponding components of the core networknode 808. 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).

[0109] The host 816 may be under the ownership or control of a service provider other than anoperator or provider of the access network 804 and / or the telecommunication network 802. The host 816 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.

[0110] As a whole, the communication system 800 of Figure 8 enables connectivity between theUEs, 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.

[0111] In some examples, the telecommunication network 802 is a cellular network thatimplements 3GPP standardized features. Accordingly, the telecommunications network 802 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 802. For example, the telecommunications network 802 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providingEnhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive IoT services to yet further UEs.

[0112] In some examples, the UEs 812 are configured to transmit and / or receive informationwithout direct human interaction. For instance, a UE may be designed to transmit information to the access network 804 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 804. Additionally, a UE may be configured for operatingin single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one orcombination 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) NewRadio – Dual Connectivity (EN-DC).

[0113] In the example, the hub 814 communicates with the access network 804 to facilitateindirect communication between one or more UEs (e.g., UE 812c and / or 812d) and network nodes (e.g., network node 810b). In some examples, the hub 814 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 814 may be a broadband router enabling access to the core network 806 for the UEs. As another example, the hub 814 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 810, or by executable code, script, process, or other instructions in the hub 814. As another example, the hub 814 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 814 may be a contentsource. For example, for a UE that is a VR device, display, loudspeaker, or other media delivery device,the hub 814 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 814 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 814 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy IoT devices.

[0114] The hub 814 may have a constant / persistent or intermittent connection to the network node810b. The hub 814 may also allow for a different communication scheme and / or schedule between the hub 814 and UEs (e.g., UE 812c and / or 812d), and between the hub 814 and the core network 806. In other examples, the hub 814 is connected to the core network 806 and / or one or more UEs via a wired connection. Moreover, the hub 814 may be configured to connect to an M2M service provider over the access network 804 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 810 while still connected via the hub 814 via a wired orwireless connection. In some embodiments, the hub 814 may be a dedicated hub – that is, a hub whoseprimary function is to route communications to / from the UEs from / to the network node 810b. In otherembodiments, the hub 814 may be a non-dedicated hub – that is, a device which is capable of operatingto route communications between the UEs and network node 810b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0115] Figure 9 shows a UE 900 in accordance with some embodiments. The UE 900 presentsadditional details of some embodiments of the UE 812 of Figure 1. 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 digitalassistant (PDA), wireless cameras, gaming console or device, music storage / playback device, wearableterminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), an Augmented Reality (AR) or Virtual Reality (VR) device, wireless customer-premise equipment (CPE), vehicle, 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.

[0116] A UE may support device-to-device (D2D) communication, for example by implementinga 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).

[0117] The UE 900 includes processing circuitry 902 that is operatively coupled via a bus 904 toan input / output interface 906, a power source 908, a memory 910, a communication interface 912, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 9. 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.

[0118] The processing circuitry 902 is configured to process instructions and data and may beconfigured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 910. The processing circuitry 902 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 902 mayinclude multiple central processing units (CPUs). The processing circuitry 902 may be configured to cause the UE 902 to perform the methods as described with reference to Figure 2.

[0119] In the example, the input / output interface 906 may be configured to provide an interfaceor 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 900. 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.

[0120] In some embodiments, the power source 908 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 908 may further include power circuitry for delivering power from the power source 908 itself, and / or an external power source, to the various parts of the UE 900 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 908. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 908 to make the power suitable for the respective components of the UE 900 to which power is supplied.

[0121] The memory 910 may be or be configured to include memory such as random accessmemory (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 910 includes one or more application programs 914, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 916. The memory 910 may store, for use by the UE 900, any of a variety of various operating systems or combinations of operating systems.

[0122] The memory 910 may be configured to include a number of physical drive units, such asredundant 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 resistantmodule 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 910 may allow the UE 900 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 910, which may be or comprise a device-readable storage medium.

[0123] The processing circuitry 902 may be configured to communicate with an access networkor other network using the communication interface 912. The communication interface 912 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 922. The communication interface 912 may include one or more 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 918 and / or a receiver 920 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 918 and receiver 920 may be coupled to one or more antennas (e.g., antenna 922) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0124] In the illustrated embodiment, communication functions of the communication interface912 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 / internet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0125] Regardless of the type of sensor, a UE may provide an output of data captured by itssensors, through its communication interface 912, 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).

[0126] As another example, a UE comprises an actuator, a motor, or a switch, related to acommunication 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.

[0127] A UE, when in the form of an Internet of Things (IoT) device, may be a device for use inone 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 IoT 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, awearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking 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 IoT device comprises circuitry and / or software in dependence of the intended application of the IoT device in addition to other components as described in relation to the UE 900 shown in Figure 9.

[0128] As yet another specific example, in an IoT scenario, a UE may represent a machine orother device that performs monitoring and / or measurements, and transmits the results of suchmonitoring and / or measurements to another UE and / or a network node. The UE may in this case be anM2M 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.

[0129] In practice, any number of UEs may be used together with respect to a single use case. Forexample, 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.

[0130] Figure 10 shows a network node 1000 in accordance with some embodiments. As usedherein, 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 NR NodeBs (gNBs)), O-RAN nodes or components of an O-RAN node (e.g., O-RU, O- DU, O-CU).

[0131] Base stations may be categorized based on the amount of coverage they provide (or, stateddifferently, 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, distributed units (e.g., in an O-RAN access node) 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).

[0132] Other examples of network nodes include multiple transmission point (multi-TRP) 5Gaccess 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).

[0133] The network node 1000 includes a processing circuitry 1002, a memory 1004, acommunication interface 1006, and a power source 1008. The network node 1000 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 1000 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 1000 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1004 for different RATs) and some components may be reused (e.g., a same antenna 1010 may be shared by different RATs). The network node 1000 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1000, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) orBluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1000.

[0134] The processing circuitry 1002 may comprise a combination of one or more of amicroprocessor, 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 1000 components, such as the memory 1004, to provide network node 1000 functionality. For example, the processing circuitry 1002 may be configured tocause the network node to perform the methods as described with reference to Figure 3, 4 and / or 5.

[0135] In some embodiments, the processing circuitry 1002 includes a system on a chip (SOC).In some embodiments, the processing circuitry 1002 includes one or more of radio frequency (RF) transceiver circuitry 1012 and baseband processing circuitry 1014. In some embodiments, the radio frequency (RF) transceiver circuitry 1012 and the baseband processing circuitry 1014 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 1012 and baseband processing circuitry 1014 may be on the same chip or set of chips, boards, or units.

[0136] The memory 1004 may comprise any form of volatile or non-volatile computer-readablememory 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 1002. The memory 1004 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 1002 and utilized by the network node 1000. The memory 1004 may be used to store any calculations made by the processing circuitry 1002 and / or any data received via the communication interface 1006. In some embodiments, the processing circuitry 1002 and memory 1004 is integrated.

[0137] The communication interface 1006 is used in wired or wireless communication ofsignaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 1006 comprises port(s) / terminal(s) 1016 to send and receive data, for example to and from a network over a wired connection. The communication interface 1006 also includes radio front-end circuitry 1018 that may be coupled to, or in certain embodiments a part of, the antenna 1010. Radio front-end circuitry 1018 comprises filters 1020 and amplifiers 1022. The radio front-end circuitry 1018 may be connected to an antenna 1010 and processing circuitry 1002. The radio front-end circuitry may be configured to condition signals communicated between antenna 1010 and processing circuitry1002. The radio front-end circuitry 1018 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 1018 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1020 and / or amplifiers 1022. The radio signal may then be transmitted via the antenna 1010. Similarly, when receiving data, the antenna 1010 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1018. The digital data may be passed to the processing circuitry 1002. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0138] In certain alternative embodiments, the network node 1000 does not include separate radiofront-end circuitry 1018, instead, the processing circuitry 1002 includes radio front-end circuitry and is connected to the antenna 1010. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1012 is part of the communication interface 1006. In still other embodiments, the communication interface 1006 includes one or more ports or terminals 1016, the radio front-end circuitry 1018, and the RF transceiver circuitry 1012, as part of a radio unit (not shown), and the communication interface 1006 communicates with the baseband processing circuitry 1014, which is part of a digital unit (not shown).

[0139] The antenna 1010 may include one or more antennas, or antenna arrays, configured to sendand / or receive wireless signals. The antenna 1010 may be coupled to the radio front-end circuitry 1018 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1010 is separate from the network node 1000 and connectable to the network node 1000 through an interface or port.

[0140] The antenna 1010, communication interface 1006, and / or the processing circuitry 1002may 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 1010, the communication interface 1006, and / or the processing circuitry 1002 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.

[0141] The power source 1008 provides power to the various components of network node 1000in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1008 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1000 with power for performing the functionality described herein. For example, the network node 1000 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 1008. As a further example, the power source 1008 may comprise a source of power in the formof 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.

[0142] Embodiments of the network node 1000 may include additional components beyond thoseshown in Figure 10 for providing certain aspects of the network node’s functionality, including any ofthe functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 1000 may include user interface equipment to allow input of information into the network node 1000 and to allow output of information from the network node 1000. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1000. In some embodiments providing a core network node, such as core network node 108 of FIG.8, some components, such as the radio front-end circuitry 1018 and the RF transceiver circuitry 1012 may be omitted.

[0143] Figure 11 is a block diagram illustrating a virtualization environment 1100 in whichfunctions 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 1100 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 radioconnectivity (e.g., a core network node or host), then the node may be entirely virtualized. In someembodiments, the virtualization environment 1100 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and OrchestrationFramework via an O-2 interface. Virtualization may facilitate distributed implementations of a networknode, UE, core network node, or host.

[0144] Applications 1102 (which may alternatively be called software instances, virtualappliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualizationenvironment Q400 to implement some of the features, functions, and / or benefits of some of theembodiments disclosed herein.

[0145] Hardware 1104 includes processing circuitry, memory that stores software and / orinstructions 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 1106 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1108a and 1108b (one or more of which may be generally referred to as VMs 1108), and / or perform any of the functions, features and / orbenefits described in relation with some embodiments described herein. The virtualization layer 1106 may present a virtual operating platform that appears like networking hardware to the VMs 1108.

[0146] The VMs 1108 comprise virtual processing, virtual memory, virtual networking orinterface and virtual storage, and may be run by a corresponding virtualization layer 1106. Different embodiments of the instance of a virtual appliance 1102 may be implemented on one or more of VMs 1108, 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.

[0147] In the context of NFV, a VM 1108 may be a software implementation of a physicalmachine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 1108, and that part of hardware 1104 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 1108 on top of the hardware 1104 and corresponds to the application 1102.

[0148] Hardware 1104 may be implemented in a standalone network node with generic or specificcomponents. Hardware 1104 may implement some functions via virtualization. Alternatively, hardware 1104 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 1110, which, among others, oversees lifecycle management of applications 1102. In some embodiments, hardware 1104 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 1112 which may alternatively be used for communication between hardware nodes and radio units.

[0149] Although the computing devices described herein (e.g., UEs, network nodes) may includethe 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 locatedwithin 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.

[0150] In certain embodiments, some or all of the functionality described herein may be providedby 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.EMBODIMENTS Group A Embodiments1. A method performed by a user equipment for enabling performance of early uplink, UL,synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the UE from a servingnetwork node to a candidate network node, the method comprising: receiving, from the serving network node, a first indication of one or more first dynamicresources for utilizing in performing the early uplink synchronization; receiving, from the serving network node, a second indication of one or more updated dynamic resources; and utilizing the one or more updated dynamic resources to perform the early uplink synchronization.2. The method of embodiment 1 wherein the serving network node comprises one of:a serving distributed unit, DU, and a serving base station (gNB).3. The method of embodiment 1 or 2 wherein the candidate network node comprises one of: acandidate distributed unit, DU and a candidate base station.4. The method of embodiment 1 to 3, wherein the one or more first dynamic resources comprisesone or more of: Secondary Cell, SCell, activation / deactivation indication(s)Channel State Information, CSI, measurement configuration activation / deactivationindication(s) Transmission Configuration Indication, TCI, state(s) indication(s)Spatial relation indication Reference Signal, RS, indicationUplink, UL, grantPhysical Uplink Control Channel, PUCCH, configurationPhysical Random Access Channel, PRACH, configuration to be used;Downlink, DL, bandwidth part, BWP, identifier, IDUplink, UL, bandwidth part, BWP, identifier, IDCell, Radio Number Temporary Identifier, C-RNTI, out of a setTimer value Timing advance informationConfigured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configurationScell configuration indication; and apreamble index.5. The method of any one of embodiments 1 to 4 wherein the first indication of the one or more firstdynamic resources and / or the second indication of the one or more updated dynamic resources is received on lower layer signalling.6. The method of any one of embodiments 1 to 5, wherein the second indication of one or moreupdated dynamic resources updates a subset of the one or more first dynamic resources, andwherein the method comprises:utilizing the one or more updated dynamic resources and one or more of the first dynamic resources not updated by the second indication to perform the early uplinksynchronization.7. The method of any one of embodiments 1 to 5, wherein the second indication of one or moreupdated dynamic resources updates a subset of the one or more first dynamic resources, themethod comprises: refraining from utilizing the one or more of the first dynamic resources not updated by second indication to perform the early uplink synchronization.8. The method of any one of embodiments 1 to 7, wherein the LTM cell switch is one of: intra-CU,inter CU or inter-gNB. Group B Embodiments9. A method, performed by a first network node, for enabling performance of early uplink, UL,synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of a UE from a servingnetwork node to a second network node, the method comprising: transmitting, to the second network node, a first request for a first indication of one or morefirst dynamic resources to be used by the UE for the early UL synchronization; andreceiving, from the second network node, the first indication of the one or more first dynamicresources.10. The method of embodiment 9 further comprising:responsive to receiving the first indication of the one or more first dynamic resources,forwarding the first indication to a third network node or to the UE.11. The method of embodiment 9 or 10, further comprising:receiving, from the second network node, a second indication of one or more updateddynamic resources.12. The method of embodiment 11 wherein the second indication of one or more updated dynamicresources adjusts, removes or adds to the one or more first dynamic resources.13. The method of embodiment 11 or 12, further comprising:responsive to receiving the second indication, forwarding the second indication to the third network node or the UE.14. The method of embodiments 11 or 12 further comprising, responsive to receiving the secondindication, transmitting a response message to indicate that the update to the one or more first dynamic resource has failed.15. The method of any one of embodiments 9 to 14 wherein the one or more first dynamic resourcescomprises one or more of: Secondary Cell, SCell, activation / deactivation indication(s) Channel State Information, CSI, measurement configuration activation / deactivation indication(s) Transmission Configuration Indication, TCI, state(s) indication(s) Spatial relation indication Reference Signal, RS, indication Uplink, UL, grant Physical Uplink Control Channel, PUCCH, configuration Physical Random Access Channel, PRACH, configuration to be used; Downlink, DL, bandwidth part, BWP, identifier, ID Uplink, UL, bandwidth part, BWP, identifier, ID Cell, Radio Number Temporary Identifier, C-RNTI, out of a set Timer value Timing advance information Configured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configuration Scell configuration indication; anda preamble index.16. The method of any one of embodiments 9 to 15 wherein the first request comprises a UE identifierof the UE associated with the one or more first dynamic resources.17. The method of any one of embodiments 9 to 16, wherein the LTM cell switch is one of: intra-CU, inter CU or inter-gNB.18. The method of any one of embodiments 9 to 17, wherein the first network node comprises theserving network node or, a serving distributed unit, DU, connected to the first network nodecomprises the serving network node.19. The method of embodiment any one of embodiments 9 to 18, wherein the second network nodecomprises one of: a candidate distributed unit, DU and a candidate base station.20. A method, performed by a second network node, for enabling performance of early uplink, UL,synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of UE from a servingnetwork node to the second network node, the method comprising: receiving, from a first network node, a first request for a first indication of one or morefirst dynamic resources to be used by the UE for the early UL synchronization; and transmitting, to the second network node, the first indication of the one or more first dynamicresources.21. The method of embodiment 20 further comprising, receiving from the UE initiation of the earlyUL synchronization utilizing the one or more first dynamic resources.22. The method of embodiment 20 or 21 further comprising:transmitting, to the second network node, a second indication of one or more updated dynamic resources.23. The method of embodiment 22 wherein the second indication of one or more updated dynamicresources adjusts, removes or adds to the one or more first dynamic resources.24. The method of embodiment 22 to 23, further comprising:responsive to transmitting the second indication, receiving from the UE, initiation of the early UL synchronization utilizing the one or more updated dynamic resources.The method of any one of embodiments 20 to 24, wherein the first network node comprises oneof the serving network node, or a serving a serving central unit, CU, and a serving base station(gNB).The method of any one of embdoiments 20 to 25, wherein the second network node comprisesone of: a candidate distributed unit, DU and a candidate base station (gNB).The method of any one of embodiments 20 to 26, wherein the LTM cell switch is one of: intra-CU, inter-CU or inter-gNB.The method of any one of embodiments 20 to 27, wherein the one or more first dynamic resourcescomprises one or more of: Secondary Cell, SCell, activation / deactivation indication(s) Channel State Information, CSI, measurement configuration activation / deactivation indication(s) Transmission Configuration Indication, TCI, state(s) indication(s) Spatial relation indication Reference Signal, RS, indication Uplink, UL, grant Physical Uplink Control Channel, PUCCH, configuration Physical Random Access Channel, PRACH, configuration to be used; Downlink, DL, bandwidth part, BWP, identifier, ID Uplink, UL, bandwidth part, BWP, identifier, ID Cell, Radio Number Temporary Identifier, C-RNTI, out of a set Timer value Timing advance information Configured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configuration Scell configuration indication; and a preamble index.29. A method performed by a third network node, for enabling performance of early uplink, UL,synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of UE from the third network node to a second network node, the method comprising: receiving, from a first network node, a first indication of one or more first dynamic resources to be used by the UE for the early UL synchronization; and transmitting, to the user equipment, the first indication of the one or more first dynamicresources.30. The method as claimed in claim 29 wherein:the third network node comprises a serving distributed unit, DU,the first network node comprises a serving central unit, CU, andthe second network node comprises a candidate DU.31. The method as claimed in claim 29 or 30 further comprising:receiving, from the first network node, a second indication of one or more updated dynamic resources to be used by the UE for the early UL synchronization; transmitting, to the user equipment, the second indication.32. The method of any one of embodiments 29 to 31 wherein the one or more first dynamic resourcescomprises one or more of: Secondary Cell, SCell, activation / deactivation indication(s) Channel State Information, CSI, measurement configuration activation / deactivation indication(s) Transmission Configuration Indication, TCI, state(s) indication(s) Spatial relation indication Reference Signal, RS, indication Uplink, UL, grant Physical Uplink Control Channel, PUCCH, configuration Physical Random Access Channel, PRACH, configuration to be used; Downlink, DL, bandwidth part, BWP, identifier, ID Uplink, UL, bandwidth part, BWP, identifier, ID Cell, Radio Number Temporary Identifier, C-RNTI, out of a set Timer value Timing advance information Configured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configurationScell configuration indication; and a preamble index.33. The method as claimed in any one of embodiments 29 to 32 further comprising:transmitting a request, to the first network node for the first indication. Group C Embodiments34. A user equipment for enabling performance of early uplink, UL, synchronization for a Layer1 / Layer 2 triggered mobility, LTM, cell switch, comprising: processing circuitry configured to cause the user equipment to perform any of the steps of anyof the Group A embodiments; and power supply circuitry configured to supply power to the processing circuitry.35. A network node for enabling performance of early uplink, UL, synchronization for a Layer1 / Layer 2 triggered mobility, LTM, cell switch, the network node comprising: processing circuitry configured to cause the network node to perform any of the steps of any of the Group B embodiments; power supply circuitry configured to supply power to the processing circuitry.36. A user equipment (UE) for enabling performance of early uplink, UL, synchronization for a Layer1 / Layer 2 triggered mobility, LTM, cell switch, 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 cause the user equipment to perform any of the steps of any of the Group A 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, performed by a first network node, for enabling performance of early uplink, UL,synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of a UE from a serving network node to a second network node, the method comprising: transmitting (302), to the second network node, a first request for a first indication of oneor more first dynamic resources to be used by the UE for the early UL synchronization; and receiving (304), from the second network node, the first indication of the one or more firstdynamic resources.

2. The method of claim 1 further comprising:responsive to receiving the first indication of the one or more first dynamic resources, forwarding the first indication to a third network node or to the UE.

3. The method of claim 1 or 2, further comprising:receiving, from the second network node, a second indication of one or more updated dynamic resources.

4. The method of claim 3 wherein the second indication of one or more updated dynamic resourcesadjusts, removes or adds to the one or more first dynamic resources.

5. The method of claim 3 or 4, further comprising:responsive to receiving the second indication, forwarding the second indication to the third network node or the UE.

6. The method of claims 3 or 4 further comprising, responsive to receiving the second indication,transmitting a response message to indicate that the update to the one or more first dynamic resource has failed.

7. The method of any one of claims 1 to 6 wherein the one or more first dynamic resourcescomprises one or more of: Secondary Cell, SCell, activation / deactivation indication(s) Channel State Information, CSI, measurement configuration activation / deactivation indication(s) Transmission Configuration Indication, TCI, state(s) indication(s) Spatial relation indicationReference Signal, RS, indication Uplink, UL, grant Physical Uplink Control Channel, PUCCH, configuration Physical Random Access Channel, PRACH, configuration to be used; Downlink, DL, bandwidth part, BWP, identifier, ID Uplink, UL, bandwidth part, BWP, identifier, ID Cell, Radio Number Temporary Identifier, C-RNTI, out of a set Timer value Timing advance information Configured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configuration Scell configuration indication; and a preamble index.

8. The method of any one of claims 1 to 7 wherein the first request comprises a UE identifier of theUE associated with the one or more first dynamic resources.

9. A method, performed by a second network node, for enabling performance of early uplink, UL,synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of UE from a serving network node to the second network node, the method comprising: receiving (402), from a first network node, a first request for a first indication of one ormore first dynamic resources to be used by the UE for the early UL synchronization; and transmitting (404), to the first network node, the first indication of the one or more firstdynamic resources.

10. The method of claim 9 further comprising, receiving from the UE initiation of the early ULsynchronization utilizing the one or more first dynamic resources.

11. The method of claim 9 or 10 further comprising:transmitting, to the first network node, a second indication of one or more updated dynamicresources.

12. The method of claim 11 wherein the second indication of one or more updated dynamic resourcesadjusts, removes or adds to the one or more first dynamic resources.

13. The method of claim 11 to 12, further comprising:responsive to transmitting the second indication, receiving from the UE, initiation of the early UL synchronization utilizing the one or more updated dynamic resources.

14. The method of any one of claims 9 to 13, wherein the one or more first dynamic resourcescomprises one or more of: Secondary Cell, SCell, activation / deactivation indication(s) Channel State Information, CSI, measurement configuration activation / deactivation indication(s) Transmission Configuration Indication, TCI, state(s) indication(s) Spatial relation indication Reference Signal, RS, indication Uplink, UL, grant Physical Uplink Control Channel, PUCCH, configuration Physical Random Access Channel, PRACH, configuration to be used; Downlink, DL, bandwidth part, BWP, identifier, ID Uplink, UL, bandwidth part, BWP, identifier, ID Cell, Radio Number Temporary Identifier, C-RNTI, out of a set Timer value Timing advance information Configured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configuration Scell configuration indication; and a preamble index.

15. A method performed by a third network node, for enabling performance of early uplink, UL,synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of UE from the third network node to a second network node, the method comprising: receiving (502), from a first network node, a first indication of one or more first dynamicresources to be used by the UE for the early UL synchronization; and transmitting (504), to the user equipment, the first indication of the one or more first dynamicresources.

16. The method as claimed in claim 15 further comprising:receiving, from the first network node, a second indication of one or more updated dynamic resources to be used by the UE for the early UL synchronization; transmitting, to the user equipment, the second indication.

17. The method of any one of claims 15 to 16 wherein the one or more first dynamic resourcescomprises one or more of: Secondary Cell, SCell, activation / deactivation indication(s) Channel State Information, CSI, measurement configuration activation / deactivation indication(s) Transmission Configuration Indication, TCI, state(s) indication(s) Spatial relation indication Reference Signal, RS, indication Uplink, UL, grant Physical Uplink Control Channel, PUCCH, configuration Physical Random Access Channel, PRACH, configuration to be used; Downlink, DL, bandwidth part, BWP, identifier, ID Uplink, UL, bandwidth part, BWP, identifier, ID Cell, Radio Number Temporary Identifier, C-RNTI, out of a set Timer value Timing advance information Configured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configuration Scell configuration indication; and a preamble index.

18. A method performed by a user equipment for enabling performance of early uplink, UL,synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the UE from a serving network node to a candidate network node, the method comprising: receiving (202), from the serving network node, a first indication of one or more firstdynamic resources for utilizing in performing the early uplink synchronization; receiving (204), from the serving network node, a second indication of one or more updateddynamic resources; and utilizing (206) the one or more updated dynamic resources to perform the early uplink synchronization.

19. The method of claim 18, wherein the one or more first dynamic resources comprises one or moreof: Secondary Cell, SCell, activation / deactivation indication(s) Channel State Information, CSI, measurement configuration activation / deactivation indication(s) Transmission Configuration Indication, TCI, state(s) indication(s) Spatial relation indication Reference Signal, RS, indication Uplink, UL, grant Physical Uplink Control Channel, PUCCH, configuration Physical Random Access Channel, PRACH, configuration to be used; Downlink, DL, bandwidth part, BWP, identifier, ID Uplink, UL, bandwidth part, BWP, identifier, ID Cell, Radio Number Temporary Identifier, C-RNTI, out of a set Timer value Timing advance information Configured grant configuration Physical Uplink Control Channel PUCCH for Scheduling Request, SR, configuration Scell configuration indication; and a preamble index.

20. The method of any one of claims 18 to 19, wherein the first indication of the one or more firstdynamic resources and / or the second indication of the one or more updated dynamic resources is received on lower layer signalling.

21. The method of any one of claims 18 to 20, wherein the second indication of one or more updateddynamic resources updates a subset of the one or more first dynamic resources, and wherein the method comprises: utilizing the one or more updated dynamic resources and one or more of the first dynamic resources not updated by the second indication to perform the early uplink synchronization.

22. The method of any one of claims 18 to 20, wherein the second indication of one or more updateddynamic resources updates a subset of the one or more first dynamic resources, the method comprises: refraining from utilizing the one or more of the first dynamic resources not updated by second indication to perform the early uplink synchronization.

23. A first network node (1000, 640, 720) for enabling performance of early uplink, UL,synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of a UE from a serving network node to a second network node, the first network node comprising processing circuitry (1002) and a memory (1004), the memory containing instructions executable by theprocessing circuitry whereby the first network node is operable to: transmit (302), to the second network node, a first request for a first indication of one ormore first dynamic resources to be used by the UE for the early UL synchronization; and receive (304), from the second network node, the first indication of the one or more firstdynamic resources.

24. The first network node as claimed in claim 23 wherein the memory further contains instructionsexecutable by the processing circuitry whereby the first network node is operable to perform the method as claimed in any one of claims 2 to 8.

25. A second network node (1000, 630, 730), for enabling performance of early uplink, UL,synchronization for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of UE from a serving network node to the second network node, the second network node comprising processing circuitry (1002) and a memory (1004), the memory containing instructions executable by theprocessing circuitry whereby the second network node is operable to: receive (402), from a first network node, a first request for a first indication of one or morefirst dynamic resources to be used by the UE for the early UL synchronization; and transmit (404), to the first network node, the first indication of the one or more first dynamicresources.

26. The second network node as claimed in claim 25 wherein the memory further containsinstructions executable by the processing circuitry whereby the second network node is operable to perform the method as claimed in any one of claims 10 to 14.

27. A third network node (1000, 620), for enabling performance of early uplink, UL, synchronizationfor a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of UE from the third network node to a second network node, the third network node comprising processing circuitry (1002) and a memory (1004), the memory containing instructions executable by the processing circuitrywhereby the third network node is operable to:receive (502), from a first network node, a first indication of one or more first dynamicresources to be used by the UE for the early UL synchronization; and transmit (504), to the user equipment, the first indication of the one or more first dynamicresources.

28. The third network node as claimed in claim 27 wherein the memory further contains instructionsexecutable by the processing circuitry whereby the third network node is operable to perform the method as claimed in any one of claims 16 to 17.

29. A user equipment (600, 700, 900) for enabling performance of early uplink, UL, synchronizationfor a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the UE from a serving network node to a candidate network node, the user equipment comprising processing circuitry (902) anda memory (910), the memory containing instructions executable by the processing circuitrywhereby the user equipment is operable to: receive (202), from the serving network node, a first indication of one or more firstdynamic resources for utilizing in performing the early uplink synchronization; receive (204), from the serving network node, a second indication of one or more updateddynamic resources; and utilize (206) the one or more updated dynamic resources to perform the early uplinksynchronization.

30. The user equipment as claimed in claim 29 wherein the memory further contains instructionsexecutable by the processing circuitry whereby the user equipment is operable to perform the method as claimed in any one of claims 19 to 2231. A computer program, comprising instructions which, when executed on at least one processor,cause the at least one processor to carry out a method according to any of claims 1 to 22.

32. A computer-readable medium comprising instructions that, when executed on at least oneprocessor, cause the at least one processor to perform the method according to any of claims 1 to 22.

33. A computer program product comprising non transitory computer readable media having storedthereon a computer program according to claim 31.

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