Logging and reporting of information associated with UE mobility operation

Abstract

Techniques for improving mobility of a user equipment, UE, across mulple cells in a wireless network An example method, in a UE operang in a wireless network, comprises the step of receiving (910), from the wireless network, a command instrucng the UE to perform downlink pre- synchronizaon for a candidate target cell for mobility or informing the UE that downlink synchronizaon for the candidate target cell for mobility is no longer needed. The example method further comprises the step of subsequently logging (920), in response to a successful change or addion of cell or in response to a failed mobility procedure, informaon idenfying and / or otherwise regarding one or more candidate cells and / or beams indicated in the command. The UE may subsequently include the logged informaon in a Radio Link Failure, RLF, report or a Successful Handover Report (SHR), for example.

Description

[0001] LOGGING AND REPORTING OF INFORMATION ASSOCIATED WITH UE MOBILITY OPERATION

[0002] TECHNICAL FIELD

[0003] The present application relates generally to the field of wireless networks, and more specifically to improving mobility operation of user equipment (UEs) across multiple cells in a wireless network, specifically mobility based on layer-1 (LI) and / or layer-2 (L2) procedures that incur less delay than conventional layer-3 mobility procedures.

[0004] BACKGROUND

[0005] Currently the fifth generation (5G) of cellular systems is being standardized within the Third- Generation Partnership Project (3GPP). NR is developed for maximum flexibility to support multiple and substantially different use cases. These include enhanced mobile broadband (eMBB), machine type communications (MTC), ultra-reliable low latency communications (URLLC), side-link device-to- device (D2D), and several other use cases.

[0006] Figure 1 illustrates a high-level view of an exemplary 5G network architecture, consisting of a Next Generation Radio Access Network (NG-RAN, 199) and a 5G Core (5GC, 198). The NG-RAN can include one or more gNodeBs (gNBs) connected to the 5GC via one or more NG interfaces, such as gNBs (100, 150) connected via respective interfaces (102, 152). More specifically, the gNBs can be connected to one or more Access and Mobility Management Functions (AMFs) in the 5GC via respective NG-C interfaces and to one or more User Plane Functions (UPFs) in 5GC via respective NG- U interfaces. The 5GC can include various other network functions (NFs), such as Session Management Function(s) (SMF).

[0007] Figure 2 shows an exemplary configuration of NR user plane (UP) and control plane (CP) protocol stacks in a UE 2101 and gNB 220. The Non-Access Stratum (NAS) layer in the UE 201 is terminated in the Access and Mobility Function (AMF) 230, while the other layers of the UP and CP protocol stacks in the UE 210 are terminated in respective layers in the gNB 220.

[0008] Although not shown in Figure 1, in some deployments the 5GC can be replaced by an Evolved Packet Core (EPC), which conventionally has been used together with a fourth generation (4G) Long-Term Evolution (LTE) Evolved UMTS RAN (E-UTRAN). In such deployments, gNBs (e.g., 100, 150) can connect to one or more Mobility Management Entities (MMEs) in EPC 198 via respective Sl-C interfaces. Similarly, gNBs can connect to one or more Serving Gateways (SGWs) in EPC via respective NG-U interfaces. In addition, the gNBs can be connected to each other via one or more Xn interfaces, such as Xn interface (140) between gNBs (100, 150). The radio technology for the NG-RAN is often referred to as "New Radio" (NR). With respect to the NR interface to UEs, each of the gNBs can support frequency division duplexing (FDD), time division duplexing (TDD), or a combination thereof. Each of the gNBs can serve a geographic coverage area including one or more cells and, in some cases, can also use various directional beams to provide coverage in the respective cells. In general, a DL "beam" is a coverage area of a network-transmitted reference signal (RS) that may be measured or monitored by a UE.

[0009] NG RAN logical nodes (e.g., gNB 100) include a Central Unit (CU or gNB-CU, e.g., 110) and one or more Distributed Units (DU or gNB-DU, e.g., 120, 130). CUs are logical nodes that host higher-layer protocols and perform various gNB functions such controlling the operation of DUs. DUs are decentralized logical nodes that host lower layer protocols and can include, depending on the functional split option, various subsets of the gNB functions. Each CU and DU can include various circuitry needed to perform their respective functions, including processing circuitry, communication interface circuitry (e.g., transceivers), and power supply circuitry.

[0010] A gNB-CU connects to one or more gNB-DUs over respective Fl logical interfaces (e.g., 122 and 132 shown in Figure 1). However, a gNB-DU can be connected to only a single gNB-CU. The gNB-CU and its connected gNB-DU(s) are only visible to other gNBs and the 5GC as a gNB. In other words, the Fl interface is not visible beyond gNB-CU.

[0011] Seamless handovers are a key feature of 3GPP technologies. A UE is handed over from a source or serving cell, provided by a source node, to a target cell provided by a target node. Successful handovers ensure that the UE moves around in the coverage area of different cells without causing too many interruptions in the data transmission. However, handover can have various problems related to robustness. For example, a handover command (e.g., RRCReconfiguration message including a reconfigurationWithSync information element) is normally sent when the radio conditions for the UE are already quite bad and may not reach the UE before the UE's degraded connection with the source node / cell is dropped.

[0012] Upon receiving a handover command, a UE starts a timer T304 to monitor whether the handover is successful. Upon T304 expiry the UE considers the handover failed and performs recovery actions such as initiation of an RRC Re-establishment procedure including cell selection while another timer T311 is running. While T304 is running, the UE's radio resource control (RRC) layer triggers a randomaccess (RA) procedure with a target cell indicated in the reconfigurationWithSync IE. The handover is considered successful when the RA procedure is successfully completed before T304 expiry. The reconfiguration with sync procedure during handover is further defined in 3GPP TS 38.331 (vl7.2.0) section 5.3.5.5.2.

[0013] A RACH-less handover was specified for LTE in 3GPP Rel-14. If the UE receives a handover command with a rach-Skip field, the UE should perform the handover to the target cell without performing a RA procedure. The UE initiates T304 in a similar manner as described above, but the handover is considered successful if the UE successfully receives certain information from the network via the target cell indicated in the handover command.

[0014] When the UE moves between the coverage areas of two cells, a serving cell change needs to be performed at some point. Currently, serving cell change is triggered by layer 3 (L3, e.g., RRC) measurements and involves RRC signaling to change PCell and / or PSCell (e.g., when dual connectivity is configured), as well as release / add SCells (e.g., when CA is configured). Currently, L3 inter-cell mobility involves complete layer 2 (L2) and layer 1 (LI, i.e., PHY) resets, leading to longer latency, increased signaling overhead, and longer interruptions than for intra-cell beam switching.

[0015] Layer 1 / Layer 2 (Ll / L2)-Triggered Mobility (LTM) in 3GPP Rel-18

[0016] Layer 1 / Layer 2-Triggered Mobility (LTM) has been specified in Release 18 of the 3GPP specifications as part of the Mobility enhancements Work Item. According to a version of the running change request (CR) for 3GPP TS 38.300, LTM is a procedure in which a gNB receives LI measurement report(s) from a UE and, on their basis, changes a UE's serving cell using a cell switch command signalled via a MAC CE. The cell switch command indicates an LTM candidate cell configuration that the gNB previously prepared and provided to the UE through RRC signalling. Upon receipt of the command, the UE switches to the target cell, according to the cell switch command. The LTM procedure can be used to reduce mobility latency.

[0017] LTM supports both intra-gNB-DU and intra-gNB-CU / inter-gNB-DU mobility. LTM supports both intrafrequency and inter-frequency mobility, including mobility to an inter-frequency cell that is not a current serving cell.

[0018] Figure 3 illustrates the signaling procedure for LTM.

[0019] The steps shown in the procedure illustrated in Figure 3 are as follows:

[0020] 1. The UE sends a MeasurementReport message to the gNB. The gNB decides to configure LTM and initiates candidate cell(s) preparation. 2. The gNB transmits an RRCReconfiguration message to the UE including the LTM candidate cell configurations of one or multiple candidate cells.

[0021] 3. The UE stores the LTM candidate cell configurations and transmits an RRCReconfigurationComplete message to the gNB.

[0022] 4a. The UE may perform DL synchronization with the candidate cell(s) before receiving the cell switch command. This step may be referred to as DL pre-sync (since it occurs before the LTM cell switch comamnd is received) or early DL sync, or pre-activation of TCI states of LTM candidate cell(s).

[0023] 4b. When UE-based TA measurement is configured, UE may acquire the TA value(s) of the candidate cell (s) by measurement. Otherwise, UE may perform early TA acquisition with the candidate cell (s) as requested by the network before receiving the cell switch command. The present disclosure is more directly (but not exclusively) concerned with early DL sync, so further details of this step are not discussed here.

[0024] 5. The UE performs LI measurements on the configured candidate cell(s) and transmits LI measurement reports to the gNB. LI measurement should be performed as long as RRC reconfiguration (step 2) is applicable.

[0025] 6. The gNB decides to execute cell switch to a target cell and transmits a MAC CE triggering cell switch by including the candidate configuration index of the target cell. The UE switches to the target cell and applies the configuration indicated by candidate configuration index. The MAC CE for LTM cell switch may also include a beam indication (a TCI State ID) of the LTM candidate cell indicated by the the candidate configuration index. The network includes the beam indication based on the LI measurements reported by the UE.

[0026] 7. The UE performs a random access procedure towards the target cell, if UE does not have valid TA of the target cell. The UE performs CFRA if the LTM cell switch command MAC CE contains information for CFRA as specified in clause 6.1.3.xy of TS 38.321.

[0027] 8. The UE completes the LTM cell switch procedure by sending RRCReconfigurationComplete message to target cell. If the UE has performed a RA procedure in step 7, the UE considers that LTM cell switch execution is successfully completed when the random access procedure is successfully completed. For RACH-less LTM, the UE considers that LTM cell switch execution is successfully completed when the UE determines that the network has successfully received its first UL data. The UE determines successful reception of its first UL data by receiving a PDCCH addressing the UE's C-RNTI in the target cell, which schedules a new transmission following the first UL data. The PDCCH carries either a DL assignment or an UL grant addressing the same HARQ. process as the first UL data.

[0028] According to the above procedures, it is noted that the LTM Cell Switch command from the network to the UE includes a beam indication and an indication of an LTM candidate cell, based on which the UE accesses the indicated LTM candidate cell, i.e., the UE performs the LTM cell switch and transmits an RRC complete message (e.g., RRC Reconfiguration Complete).

[0029] In NR, that "beam indication" is specified as a Transmission Configuration Indicator (TCI) State Identity (ID) associated to the LTM candidate cell, which is indicated as an LTM candidate configuration ID in the LTM cell switch command. When the UE receives the beam indication in the LTM cell switch command (e.g., a MAC Control Element) the UE monitors a Physical Downlink Control Channel (PDCCH) on that indicated beam of that indicated LTM candidate cell: in other words, the UE considers the TCI State for the indicated TCI state ID as an activated TCI State (or pre-activated) in the indicated LTM candidate cell, when performing the LTM cell switch. The TCI state is also associated to a Reference Signal (RS) and / or synchronization signal, such as a Synchronization Signal Block (SSB) or CSI-RS, which may also be called a Quasi-Co-location (QCL) source. Thus, when a beam is indicated, one may say that an SSB and / or CSI-RS is being indicated.

[0030] Self-Organizing Networks (SON) in 3GPP

[0031] A Self-Organizing Network (SON) is an automation technology designed to make the planning, configuration, management, optimization and healing of mobile radio access networks simpler and faster. SON functionality and behavior has been defined and specified in generally accepted mobile industry recommendations produced by organizations such as 3GPP (3rd Generation Partnership Project) and the NGMN (Next Generation Mobile Networks).

[0032] In 3GPP, the processes within the SON area are classified into Self-configuration process and Selfoptimization process. Self-configuration process is the process where newly deployed nodes are configured by automatic installation procedures to get the necessary basic configuration for system operation.

[0033] This process works in pre-operational state. Pre-operational state is understood as the state from when the eNB is powered up and has backbone connectivity until the RF transmitter is switched on.

[0034] As illustrated in Figure 4, functions handled in the pre-operational state, such as basic setup and initial radio configuration, are covered by the Self Configuration process. Self-optimization process is defined as the process where UE and access node measurements and performance measurements are used to auto-tune the network. This process works in operational state. Operational state is understood as the state where the RF interface is additionally switched on. As shown in Figure 4, functions handled in the operational state such as Optimization / Adaptation are covered by the Self Optimization process.

[0035] In LTE, support for Self-Configuration and Self-Optimization is specified, as described in 3GPP TS 36.300 section 22.2, including features such as Dynamic configuration, Automatic Neighbor Relation (ANR), Mobility load balancing, Mobility Robustness Optimization (MRO), RACH optimization and support for energy saving.

[0036] In NR, support for Self-Configuration and Self-Optimization is specified as well, starting with SelfConfiguration features such as Dynamic configuration, Automatic Neighbor Relation (ANR) in Rel-15, as described in 3GPP TS 38.300 section 15. In NR Rel-16, more SON features are being specified, including Self-Optimization features such as Mobility Robustness Optimization (MRO).

[0037] Mobility Robustness Optimization (MRO) in 3GPP

[0038] Seamless handovers are a key feature of 3GPP technologies. Successful handovers ensure that the UE moves around in the coverage area of different cells without causing too much interruptions in the data transmission. However, there will be scenarios when the network fails to handover the UE to the 'correct' neighbor cell in time and in such scenarios the UE will declare a radio link failure (RLF) or Handover Failure (HOF).

[0039] Upon HOF and RLF, the UE may take autonomous actions, i.e., trying to select a cell and initiate reestablishment procedure, so that it can be reachable again. An RLF will cause a poor user experience, as the RLF is declared by the UE only when it realizes that there is no reliable communication channel (radio link) available between itself and the network. Also, reestablishing the connection requires signaling with the newly selected cell (random access procedure, RRC Reestablishment Request, RRC Reestablishment RRC Reestablishment Complete, RRC Reconfiguration and RRC Reconfiguration Complete) and adds some latency, until the UE can exchange data with the network again.

[0040] According to the specifications (3GPP TS 36.331), possible causes for the radio link failure could be one of the following:

[0041] 1) Expiry of the radio link monitoring related timer T310; 2) Expiry of the measurement reporting associated timer T312 (not receiving the handover command from the network within this timer's duration despite sending the measurement report when T310 was running);

[0042] 3) Upon reaching the maximum number of RLC retransmissions;

[0043] 4) Upon receiving random access problem indication from the MAC entity;

[0044] As RLF leads to reestablishment, which degrades performance and user experience, it is in the interest of the network to understand the reasons for RLF and try to optimize mobility related parameters (e.g., trigger conditions of measurement reports) to avoid later RLFs. Before the standardization of MRO related report handling in the network, only the UE was aware of some information, such as how the radio quality looked at the time of RLF, the actual reason for declaring RLF, etc. For the network to identify the reason for the RLF, the network needs more information, both from the UE and also from the neighboring base stations.

[0045] As part of the MRO solution in LTE, the RLF reporting procedure was introduced in the RRC specification in Rel-9 RAN2 work. That has impacted the RRC specifications (especially 3GPP TS 36.331) in that it was standardized that the UE would log relevant information at the moment of an RLF and later report to a target cell to which the UE successfully connects (e.g., after reestablishment). That has also impacted the inter-gNodeB interface, i.e., X2AP specifications (3GPP TS 36.423), as an eNodeB receiving an RLF report could forward to the eNodeB where the failure has been originated.

[0046] For the RLF report generated by the UE, its contents have been enhanced with more details in the subsequent releases. The measurements included in the measurement report based on the latest LTE RRC specification are:

[0047] 1) Measurement quantities (RSRP, RSRQ.) of the last serving cell (PCell).

[0048] 2) Measurement quantities of the neighbor cells in different frequencies of different RATs (EUTRA, UTRA, GERAN, CDMA2000).

[0049] 3) Measurement quantity (RSSI) associated to WLAN Aps.

[0050] 4) Measurement quantity (RSSI) associated to Bluetooth beacons.

[0051] 5) Location information, if available (including location coordinates and velocity)

[0052] 6) Globally unique identity of the last serving cell, if available, otherwise the PCI and the carrier frequency of the last serving cell.

[0053] 7) Tracking area code of the PCell.

[0054] 8) Time elapsed since the last reception of the 'Handover command' message.

[0055] 9) C-RNTI used in the previous serving cell. 10) Whether or not the UE was configured with a DRB having QCI value of 1.

[0056] After an RLF is declared, the RLF report is logged and include in the VarRLF-Report and, once the UE selects a cell and succeeds with a reestablishment, it includes an indication that it has an RLF report available in the RRC Reestablishment Complete message, to make the target cell aware of that availability. Then, upon receiving an UElnformationRequest message with a flag "rlf-ReportReq-r9" the UE shall include the RLF report (stored in a UE variable VarRLF-Report, as described above) in an UElnformationResponse message and send it to the network.

[0057] Based on the RLF report from the UE and knowledge about which cell the UE reestablished itself with, the original source cell can deduce whether the RLF was caused due to a coverage hole or due to handover associated parameter configurations. If the RLF was deemed to be due to handover associated parameter configurations, the original serving cell can further classify the handover related failure among too-early, too-late, or handover to wrong cell classes. These handover failure classes are explained in brief below.

[0058] 1) Whether the handover failure occurred due to the 'too-late handover / mobility' cases a. The original serving cell can classify a handover failure to be 'too late handover / mobility' when the original serving cell fails to send the handover command to the UE associated to a handover towards a particular target cell and if the UE reestablishes itself in this target cell post RLF. b. An example corrective action from the original serving cell could be to initiate the handover procedure towards this target cell a bit earlier by decreasing the CIO (cell individual offset) towards the target cell that controls when the IE sends the event triggered measurement report that leads to taking the handover decision.

[0059] 2) Whether the handover failure occurred due to the 'too-early handover / mobility' cases a. The original serving cell can classify a handover failure to be 'too early handover / mobility' when the original serving cell is successful in sending the handover command to the UE associated to a handover however the UE fails to perform the random access towards this target cell or the UE declares RLF in the target cell soon afterwards. b. An example corrective action from the original serving cell could be to initiate the handover procedure towards this target cell a bit later by increasing the CIO (cell individual offset) towards the target cell that controls when the IE sends the event triggered measurement report that leads to taking the handover decision.

[0060] 3) Whether the handover failure occurred due to the 'handover / mobility-to-wrong-cell' cases a. The original serving cell can classify a handover failure to be 'handover / mobility-to- wrong-cell' when the original serving cell intends to perform the handover for this UE towards a particular target cell but the UE declares failure or declares failure shortly after successfully completing the handover and then reestablishes itself in a third cell. b. A corrective action from the original serving cell could be to initiate the measurement reporting procedure that leads to handover towards the target cell a bit later by decreasing the CIO (cell individual offset) towards the target cell or via initiating the handover towards the cell in which the UE reestablished a bit earlier by increasing the CIO towards the reestablishment cell.

[0061] SON and LTM

[0062] SON / MDT Enhancements remains a high priority item for standardization. There is interest in considering, for MRO:

[0063] RO enhancement for R18 mobility mechanisms, Lower layer triggered mobility (LTM), CHO with candidate SCGs, subsequent CPAC [RAN3, RAN2]: o Identify and specify necessary UE reporting to enhance the mobility parameter tuning [RAN2]

[0064] A goal of LTM cell switch is to reduce latency, overhead and interruption time. The decision to trigger an LTM cell switch procedure is taken by the source DU, while the legacy L3 mobility decisions are taken by the source CU-CP. The LTM candidate cells are expected to be configured in a UE-specific way. A UE might have limitations on how many inter-cell mobility candidates can it keep in the memory (e.g., 8 LTM candidate cells) and thus different UEs in the same DU might be configured with different LTM candidate cells depending on each UE's location, mobility characteristics and other parameters. Further, 3GPP has decided to call L1 / L2 inter-cell mobility with the name of L1 / L2 Triggered Mobility (LTM).

[0065] A SON / MDT work item in Release 19 will comprise data collection for the LTM cell switch procedure, and for the sake of troubleshooting and enhancements the existing SON reports e.g., RLF report or successful handover report, etc., might be enhanced to collect measurements and information for the LTM cell switch procedure.

[0066] Several issues remain. SUMMARY

[0067] One problem addressed by the present disclosure is that the DL synchronization procedure (TCI state pre-activation, as indicated above) consumes a significant amount of UE resources (e.g., UE power, processing, etc.). This means that the number of TCI states and / or LTM candidate cells for which the UE can perform DL pre-synchronization may be limited, compared to the number of LTM candidate cell (s) and / or TCI states the UE is configured with. Thus, it is not obvious which subset of LTM candidate cell(s) and / or TCI state(s) the network should configure for the UE for DL presynchronization and, among the configured ones, which ones to activate before the LTM cell switch is triggered.

[0068] In a typical case, the network decides the LTM candidate cells and / or TCI State I D(s) for DL pre-synch mechanism using the candidate target cell TCI activation / deactivation mechanism based on lower layer measurement reports from the UE (also called LI measurement reports for LTM), which includes measurement per beam, e.g., Synchronization Sequence Blocks (SSBs) measurements, such as LI RSRP for one or more SSBs. For example, strong LTM candidate cells in terms of Ll-RSRP and / or SSB of the LTM candidate cells are good candidates for DL pre-sync, as these are more likely to be candidates to which an LTM cell switch is going to be triggered.

[0069] However, since these measurements are not valid for a very long time and since the measurements may not be layer 3 (L3) filtered, the radio conditions may change quite quickly, so it might not always be simple for the network to determine towards which candidate cell and / or beam(s) of the candidate cell the pre-synchronization should be done. In a sub-optimal configuration, the DL presynchronization may be triggered toward an LTM candidate cell and / or beam (SSB) different from the cell that is eventually selected as target cell for the LTM cell switch procedure. This issue not only imposes extra cost on both network and the UE to unnecessarily execute DL pre-synchronization toward an LTM candidate cell but also increases the induced handover or cell switch interruption time.

[0070] Techniques, apparatuses, and systems described herein address this problem. According to at least some of these techniques, apparatuses, and systems, a UE records, or "logs," information relating to pre-synchronization operations that are triggered for the UE, such as information about the specific candidate cell(s) / beam(s) for which the UE has been triggered to perform pre-synchronization. This information can then be used by the network to optimize subsequent mobility configurations, such as for LTM, and / or to optimize subsequent pre-synchronization orders. An example method, according to some embodiments, is carried out by a user equipment (UE) operating in a wireless network and comprises the step of receiving, from the wireless network, a command instructing the UE to perform downlink pre-synchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed. This command may be, for example, a TCI state activation command or TCI state deactivation command, in the context of LTM. The method further comprises the step of subsequently logging, in response to a successful change or addition of cell or in response to a failed mobility procedure, information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in the command. This information may be included in a Radio Link Failure (RLF) report or a Successful Handover Report (SHR), for example, where the report is subsequently transmitted to the network, e.g., on request from the network.

[0071] Another example method, according to some embodiments, is carried out by a network node and comprises the step of receiving, from a user equipment (UE), a report of a successful or unsuccessful mobility event or of a radio link failure, the report comprising information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in a command from the wireless network instructing the UE to perform downlink pre-synchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed, the information having been logged by the UE in response to a subsequent successful change or addition of cell or failed mobility procedure. The information may have been logged by the UE in response to a subsequent successful change or addition of cell or failed mobility procedure. Again, this command may be, for example, a TCI state activation command or TCI state deactivation command, in the context of LTM. Likewise, the information may be received in a Radio Link Failure (RLF) report or a Successful Handover Report (SHR), for example, where the report is received by the network, e.g., in response to a request from the network.

[0072] Other embodiments include apparatuses and systems in which the methods described above and / or variants of such methods are implemented.

[0073] BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 shows a high-level view of an exemplary 5G network architecture.

[0075] Figure 2 shows an exemplary configuration of NR UP and CP protocol stacks.

[0076] Figure 3 illustrates the signaling procedure for LTM. Figure 4 shows ramifications of Self-Configuration / Self-Optimization functionality (from 3GPP TS 36.300 figure 22.1-1).

[0077] Figure 5 shows an example of logging and reporting information related to the pre-synchronization toward a candidate cell and the candidate cells' TCI state activation.

[0078] Figure 6 shows another example of logging and reporting information related to the presynchronization toward a candidate cell and the candidate cells' TCI state activation.

[0079] Figure 7 shows another example of logging and reporting information related to the presynchronization toward a candidate cell and the candidate cells' TCI state activation.

[0080] Figure 8 illustrates yet another example of logging and reporting information related to the presynchronization toward a candidate cell and the candidate cells' TCI state activation.

[0081] Figure 9 shows an exemplary method (e.g., procedure) for a UE, according to various embodiments of the present disclosure.

[0082] Figure 10 shows an exemplary method (e.g., procedure) for a network node, according to various embodiments of the present disclosure.

[0083] Figure 11 shows a communication system according to various embodiments of the present disclosure.

[0084] Figure 12 shows a UE according to various embodiments of the present disclosure.

[0085] Figure 13 shows a network node according to various embodiments of the present disclosure.

[0086] Figure 14 is a block diagram of a virtualization environment in which functions implemented by some embodiments of the present disclosure may be virtualized.

[0087] DETAILED DESCRIPTION

[0088] This disclosure may use the term "L1 / L2 based inter-cell mobility" as used in the Work Item Description in 3GPP, though it interchangeably also uses the terms L1 / L2 mobility, Ll-mobility, LI based mobility, Ll / L2-centric inter-cell mobility, L1 / L2 inter-cell mobility Ll / L2-Triggered Mobility, Lower-layer Triggered Mobility or simply LTM. The basic principle of LTM is that the UE 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) in accordance with configuration information previously received by the UE, wherein a lower layer signaling is a message / signaling of a lower layer protocol, which may be referred as a L1 / L2 inter-cell mobility execution 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 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). An LTM candidate cell configuration may include parameters in the IE CellGroupConfig per candidate cell and / or an embedded RRC Reconfiguration per LTM candidate cell.

[0089] 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 neighbor cell), using Ll / L2-triggered mobility (LTM). In the context of Ll / L2-triggered mobility (LTM), an LTM 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., PCell in case of LTM being configured for a Master Cell Group (MCG) and / or 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.

[0090] Where the term "change of cell" is used, the change of cell may comprise a change of 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).

[0091] An LTM cell switch procedure may be triggered in the UE by reception of a LTM cell switch command, e.g., a MAC CE.

[0092] This document often refers to an LTM candidate cell, which is a cell the UE is configured with when configured with Ll / L2-triggered mobility. That is, a cell the UE can move to in a LTM cell switch procedure, upon reception of a LTM cell switch command. These 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 performs measurements on (e.g., CSI measurements) so that the UE can report these measurements and the network may take educated decision on which beam (e.g. TCI state) and / or cell the UE is to be switched to. An LTM candidate cell may be a candidate to be a target PCell or PSCell, or an SCell of a cell group (e.g. MCG SCell). This disclosure also refers often to "at least one LTM candidate cell configuration" and may state that 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 Ll / L2-Triggered Mobility. A LTM candidate cell configuration comprises the configuration 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 an LTM cell switch command indicating the UE to perform a LTM 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 the UE 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).

[0093] The terms "triggering" the LTM cell switch or "executing" the LTM cell switch are used interchangeably in this disclosure.

[0094] In LTM, the LTM Cell Switch command from the network to the UE includes a beam indication and an indication of an LTM candidate cell, based on which the UE accesses the indicated LTM candidate cell, i.e., the UE performs the LTM cell switch and transmits an RRC complete message (e.g., RRC Reconfiguration Complete).

[0095] In NR, that "beam indication" is specified as a Transmission Configuration Indicator (TCI) State Identity (ID) associated to the LTM candidate cell, which is also indicated as an LTM candidate configuration ID in the LTM cell switch command. When the UE receives the beam indication in the LTM cell switch command (e.g., a MAC Control Element) the UE monitors a Physical Downlink Control Channel (PDCCH) on that indicated beam of that indicated LTM candidate cell: in other words, the UE considers the TCI State for the indicate TCI state ID as an activated TCI State (or pre-activated) in the indicated LTM candidate cell, when performing the LTM cell switch. The TCI state is also associated to a Reference Signal (RS) and / or synchronization signal, such as a Synchronization Signal Block (SSB) or CSI-RS, which may also be called a Quasi-Co-location (QCL) source. Thus, when a beam is indicated, one may say that an SSB and / or CSI-RS is being indicated.

[0096] Such a step in which the UE activates the TCI state and synchronizes with the LTM candidate cell, before it can monitor PDCCH and / or transmit a scheduling request for UL transmissions takes time. In LTM, in order to reduce the handover interruption time, downlink and uplink pre-synchronization mechanism has been introduced: the network, upon configuring one or more LTM candidate cells, can instruct the UE to perform synchronization toward one or more of the LTM candidate cells (that are different from the serving cell(s)). For instance, the TCI states of the LTM candidate cells can be activated in advance before any of those cells become the serving cell upon an LTM cell switch. This allows the UE to be DL synchronized with those cells in advance, thereby facilitating a faster cell switch to one of those cells when cell switch is triggered.

[0097] This mechanism is initiated by the serving DU (S-DU), e.g., based on lower layer measurements for one or more LTM candidate cells (LI RSRP), according to the following steps to activate / deactivate the candidate cells TCI state as specified in the MAC TS 38.321 version 18.0.0.:

[0098] - begin 3GPP specification excerpt -

[0099] 5.18.zy Candidate Cell TCI States Activation / Deactivation

[0100] The network may activate and deactivate the TCI states of LTM candidate cell(s) configured in CandidateTCI-State and CandidateTCI-UL-State by sending the Candidate Cell TCI States Activation / Deactivation MAC CE described in clause 6.1.3.xz.

[0101] The MAC entity shall:

[0102] 1> if the MAC entity receives a Candidate Cell TCI States Activation / Deactivation MAC CE on a Serving Cell:

[0103] 2> indicate to lower layers the information regarding the Candidate Cell TCI States Activation / Deactivation MAC CE.

[0104] [-.] 6.1.3.xz Candidate Cell TCI States Activation / Deactivation MAC CE

[0105] The Candidate Cell TCI States Activation / Deactivation MAC CE is identified by a MAC subheader with eLCID as specified in Table 6.2.1-lb. It has a variable size consisting of following fields:

[0106] - Candidate Cell ID: This field indicates the identity of an LTM candidate cell for which the MAC CE applies, corresponding to the Itm-Candidateld minus 1 as specified in TS 38.331 [5], The length of the field is 3 bits;

[0107] - Pi: This field indicates whether each TCI codepoint has multiple TCI states or a single TCI state. If the Pi field is set to 1, the ithTCI codepoint includes the DL TCI state and the UL TCI state. If the Pi field is set to 0, the ithTCI codepoint includes only the DL / joint TCI state or the UL TCI state. The codepoint to which a TCI state is mapped is determined by its ordinal position among all the TCI state ID fields;

[0108] - D / U: This field indicates whether the TCI state ID in the same octet is for a joint / downlink or an uplink TCI state. If this field is set to 1, the TCI state ID in the same octet is for joint / downlink TCI state. If this field is set to 0, the TCI state ID in the same octet is for uplink TCI state;

[0109] - TCI state ID: This field indicates the TCI state identified by TCI-Stateld in Itm-DL- OrJointTCI-StateToAddModList or TCI-UL-Stateld in Itm-UL-TCI-StatesToAddModList as specified in TS 38.331 [5], If D / U is set to 1, 7-bits length TCI state ID, i.e., TCI-Stateld as specified in TS 38.331 [5] is used. If D / U is set to 0, the most significant bit of TCI state ID is considered as the reserved bit and remaining 6 bits indicate the TCI-UL-Stateld as specified in TS 38.331 [5], The maximum number of activated TCI states is 16;

[0110] - R: Reserved bit, set to 0.

[0111] -ENC| 3GPP specification excerpt -

[0112] A first problem that is addressed by the techniques described herein is that the DL synchronization procedure (TCI state pre-activation, as indicated above) consumes a significant amount of UE resources (e.g., UE power, processing, etc.), so that the number of TCI states and / or LTM candidate cells for which the UE can perform DL pre-synchronization is limited, compared to the number of LTM candidate cell(s) and / or TCI states the UE is configured with. Thus, it is not obvious which subset of LTM candidate cell (s) and / or TCI state(s) the network should configure the UE for DL pre- synchronization and, among the configured ones, which ones to activate before the LTM cell switch is triggered.

[0113] In a typical case, the network decides the LTM candidate cells and / or TCI State I D(s) for DL pre-synch mechanism using the candidate target cell TCI activation / deactivation mechanism based on lower layer measurement reports from the UE (also called LI measurement reports for LTM), which includes measurement per beam, e.g., Synchronization Sequence Blocks (SSBs) measurements, such as LI RSRP for one or more SSBs. For example, a strong LTM candidate cell in terms of Ll-RSRP and / or SSB of that LTM candidate cell are good candidates for DL pre-sync, as these are more likely to be candidates to which an LTM cell switch is going to be triggered.

[0114] However, since these measurements are not valid for a very long time and since the measurements may not be layer 3 (L3) filtered, the radio conditions may change quite quickly, so it might not always be simple for the network to determine towards which candidate cell and / or beam(s) of the candidate cell the pre-synchronization should be done. In a sub-optimal / wrong configuration the DL pre-synchronization may be triggered toward an LTM candidate cell and / or beam (SSB) different from the cell that is eventually selected as target cell for the LTM cell switch procedure. This issue not only causes extra cost on both network and the UE to unnecessarily execute DL pre-synchronization toward an LTM candidate cell but also increases the induced handover or cell switch interruption time. It is also that an opportunity was lost to select the LTM candidate cell and TCI ID to which the UE would actually perform LTM cell switch.

[0115] Techniques described herein address this problem. According to at least some of these techniques, a UE records, or "logs," information identifying and / or otherwise regarding / relating to candidate cells and / or beams for mobility (e.g., LTM), in response to successful or failed mobility procedures and / or radio link failures. More particularly, this information may relate to one or more candidate cells and / or beams indicated in one or more previously received commands (such as TCI state activations and / or TCI state deactivations) instructing the the UE to perform downlink pre-synchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed subsequent LTM successes or failures. This logged information can later be reported to the network. As this information relates pre-synchronization operations to subsequent mobility operations, the information can then be used by the network to optimize pre-synchronization orders. Note that the terms "log" and "logging" may be understood as referring to the saving of information to memory. In some embodiments or instances, this logging may comprise saving the relevant information directly into a data structure that forms all or part of a RLF report or SHR report that is subsequently transmitted to the network; in other embodiments or instances, this information may be saved in memory in a record that is later modified and / or duplicated to form such a report.

[0116] In the discussion herein, these techniques are described in the context of LTM cell switch procedures, and are more particularly described with respect to TCI state activation and deactivation commands (which are sent as Medium Access Control Control Elements, MAC CEs), where the TCI state activation command is a command to perform downlink pre-synchronization, with respect to a particular cell and / or beam, and where the TCI state deactivation command is a command that informs the UE that downlink synchronization for a particular cell and / or beam is no longer necessary, such that it can be released. Despite the discussion of the techniques specifically in the LTM context and using this terminology, it should be appreciated that the techniques are more generally applicable to mobility-related scenarios, where "mobility" refers to cell changes, cell additions and removals, handovers, conditional handovers, etc., and / or where the commands instructing a UE (or other wireless device) to perform downlink pre-synch or informing a UE (or other wireless device) that downlink synchronization is no longer necessary are commands other than TCI state activation / deactivation commands and / or are known by different names.

[0117] An advantage of the techniques described herein is that the serving / source network node becomes aware of whether the pre-synchronization mechanism using the candidate cells TCI state activation / deactivation is efficient / optimized, and based on the reported information can optimize the candidate cell TCI state activation / deactivation mechanism to improve the entire mobility procedure performance.

[0118] In other words, when analyzing a SON report, e.g., an RLF report, it might become essential for the network node to know whether the UE was in synch with the target cell prior to the mobility procedure execution or not. This is particularly important for the scenarios in which the network requests the UE to perform pre-synch procedure towards, for example, cell X and beam Bl, but the UE performs mobility toward a different cell (say cell Y) or a different beam of cell X than the one instructed by the network as part of candidate cell TCI state activation mechanism.

[0119] This may help the network to determine parameters for pre-sync configuration(s). For example: assume that the UE reports that cell A was a candidate cell for which TCI states were activated, and an RLF occurs and the UE initiates re-establishment to cell A; the reports confirms to the network that cell A was indeed a good candidate, and, moreover, that it was a good idea to trigger presynchronization to it, but that the LTM switch should have been triggered earlier. Or, assume that the UE reports that cell B was a candidate cell for which TCI states were not activated, and an RLF occurs and the UE initiates re-establishment to cell B; the reports indicates to the network that cell B was a good candidate, but also indicates that perhaps next time (depending on further statistics or reports), cell B could be a good candidate cell for triggering pre-synchronization.

[0120] Figures 5-8 illustrate four example scenarios that provide context for the techniques described herein. Figure 5 shows a scenario in which a UE logs and reports the pre-synchronization-related information discussed herein upon success or failure of an LTM cell switch, including this information in a SON report subsequently sent to the network. Figure 6 shows a scenario in which a mobility procedure fails, and where the UE logs the pre-synchronization-related information described herein in an RLF report, again for later reporting to the network. Figure 7 shows a similar where a mobility procedure is successful, but a radio link failure subsequently occurs - again, the pre-synchronization information is included in an RLF report sent to the network. And, finally, Figure 8 shows a scenario where a successful mobility procedure execution is followed by the reporting of pre-synchronization information to the network in a Successful Handover Report (SHR).

[0121] All of these four procedures are examples, only - a given implementation of the techniques described herein might support some or all of these procedures, as shown, and a given implementation might vary in the exact details of the procedures. Each of these illustrated procedures, however, may be regarded as including the following steps, all or parts of which may be employed in various applications of the techniques described herein, in the context of a wireless terminal, or UE. In these applications, the UE:

[0122] 1. Receives configurations indicating one or more candidate target cells for the mobility procedures (L3 reconfiguration with synch, so called handover, or LTM cell Switch operation), from the serving RAN node (e.g., from the gNB-CU). For example, the UE receives an RRC Reconfiguration message including the IE LTM-Config which includes a list of configuration(s) per LTM candidate cell, e.g., ltm-CandidateToAddModList-rl8 SEQUENCE (SIZE (l..maxNrofLTM-Configs-rl8)) OF LTM-Candidate-rl8.

[0123] 2. Receives configurations instructing the UE to perform pre-synchronization (e.g., configurations for further TCI state activation / deactivation) toward one or more candidate cell(s). For example, each configuration per LTM candidate cell (e.g., in the IE LTM-Candidate- rl8) includes one or more TCI state configuration(s) (e.g., in the Itm-DL-OrJointTCI- StateToAddModList-rl8 SEQUENCE (SIZE (l..maxNrofCandidateTCI-State-rl8)) OF CandidateTCI-State-rl8 and / or in the ltm-UL-TCI-StatesToAddModList-rl8 SEQUENCE (SIZE (l..maxNrofCandidateUL-TCI-rl8)) OF CandidateTCI-UL-State-rl8). Each TCI state configuration for a given candidate cell indicates one or more RS(s), e.g., SSB index and / or a CSI resource identifier, associated to a beam (since different RSs may be transmitted in different spatial directions).

[0124] 3. Receives one or more TCI state activation (or pre-activation) / deactivation commands, each command indicating a candidate cell (e.g., by including a candidate cell identifier) and one or more TCI state identifiers of the indicated candidate cell (e.g., one or more TCI State IDs), wherein the command is received before a command for a mobility procedure (e.g., before a MAC CE for LTM cell switch) and while the UE is connected to a source cell. In response to a TCI state activation / deactivation command, the UE performs TCI state activation / deactivation towards the indicated candidate cells and indicated TCI state per indicated candidate cell. For example, the command may correspond to a "Candidate Cell TCI States Activation / Deactivation MAC CE" including a Candidate Cell ID and a TCI state ID, pointing to the UE's current configuration (as received in steps 1 and 2).

[0125] 4. Detects an event which is either a successful mobility procedure or a failure, after having performed the pre-synchronization, wherein the failure may be one of: i) a Radio Link Failure (RLF) in the source cell (e.g., Primary cell before a mobility procedure); ii) a mobility related failure when the UE is leaving the source cell (e.g., handover failure, reconfiguration with sync failure, LTM cell switch failure, conditional handover execution failure); iii) a RLF in a target cell (e.g., Primary cell after the mobility procedure); iv) a successful mobility procedure (e.g., reconfiguration with sycn, handover, PSCell addition / change, LTM cell switch, conditional handover execution). In some of these cases, the UE performs the mobility procedure towards a target cell either upon receiving an indication from the network node (e.g., from the gNB-CU for the L3 handover or from the gNB-DU for the LTM cell switch command) or upon fulfillment of execution condition for a conditional mobility configuration such as conditional handover configuration or conditional LTM cell switch configuration.

[0126] 5. Logs in a SON report in response of step 4 (e.g., an RLF report or a successful handover report, or a successful LTM report, or a successful PSCell change or addition report) information about one or more candidate cell(s) for which the UE has been triggered to perform pre-synchronization.

[0127] In some embodiments, the UE may log information associated with one or more candidate cell(s) indicated in the TCI state activation / deactivation command(s) in step 3, e.g., information about the LTM candidate cell (s) which had at least one TCI state activated when the event in step 2 is triggered, and / or information about the LTM candidate cell(s) which had all TCI states deactivated when the event in step 2 is triggered. The information may comprise a candidate cell identifier, such as an LTM candidate cell ID (e.g., LTM-Candidateld-rl8, encoded with fewer bits than the actual cell identifier broadcasted in the cell's system information).

[0128] In some embodiments, the UE may log information about one or more beam(s) associated with a candidate cell. For example, the UE may log information about which beam(s) of a candidate cell the UE was synchronized with, when the event in step 4 was detected, by logging one or more beam identifiers.

[0129] In some embodiments, the UE may log information about one or more TCI state(s) associated with a candidate cell. For example, the UE may log information about the LTM candidate cell(s) which had at least one TCI state activated when the event in step 2 is triggered, e.g., by logging candidate cell I D(s); and / or information about the LTM candidate cell(s) which had all TCI states deactivated when the event in step 2 is triggered, by logging other candidate I D(s); and / or the TCI states which were activated when the event was detected, by logging TCI state I D(s); and / or the TCI states which were deactivated when the event was detected, by logging other TCI state I D(s).

[0130] The procedures described above include one or more triggers for logging the pre-synchronization information, such as i) a Radio Link Failure (RLF) in a source cell (e.g., Primary cell before a mobility procedure); ii) a mobility related failure when the UE is leaving the source cell (e.g., handover failure, reconfiguration with sync failure, LTM cell switch failure, conditional handover execution failure); iii) a RLF in a target cell (e.g., Primary cell after the mobility procedure); iv) a successful mobility procedure (e.g., reconfiguration with sycn, handover, PSCell addition / change, LTM cell switch, conditional handover execution). This means that the UE would log the information as above when one or more of these occur.

[0131] In some instances or embodiments, the mobility operation fails and the UE logs the information in a radio link failure report (so called RLF-report), and includes in the report information (e.g., one or more candidate cell identifiers) and / or measurements (e.g., latest available) related to the presynchronization toward candidate cells (i.e., information related to the candidate target cells TCI state activation / deactivation)

[0132] In other embodiments or instances, the mobility operation succeeds, and the UE logs a report (e.g., successful handover report or a successful PSCell change report) and includes in the report the information (e.g., one or more candidate cell identifiers) and / or measurements (e.g., latest available) related to the pre-synchronization toward candidate cells (i.e., information related to the candidate target cells TCI state activation / deactivation)

[0133] In other embodiments or instances, the UE experiences a radio link failure after a successful mobility operation and the UE logs a radio link failure report, and includes in the report the information (e.g., one or more candidate cell identifiers) and / or measurements (e.g., latest available) related to the pre-synchronization toward candidate cells (i.e., information related to the candidate target cells TCI status, i.e., activation / deactivation)

[0134] In still other embodiments or instances, the UE experiences a radio link failure while it is in the source cell (e.g., RLF in the source cell) and the UE logs the information in a radio link failure report, and includes in the report the information (e.g., one or more candidate cell identifiers) and / or measurements (e.g., latest available) related to the pre-synchronization toward candidate cells (i.e., information related to the candidate target cells TCI state activation / deactivation). In this case, the UE may either initiate a re-establishment procedure to a cell for which the UE had performed presynchronization, or to a cell for which the UE had not performed pre-synchronization. The initiation of the re-establishment may lead to a successful mobility procedure (e.g., Conditional Handover execution, or LTM cell switch) or the continuation of a re-establishment procedure (i.e., the UE transmitting an RRC Reestablishment Request message, receiving an RRC Reestablishment in response and transmitting an RRC Reestablishment Complete).

[0135] In each of these scenarios, the UE may subsequently report to the network the logged report including the information and / or measurements related to the pre-synchronization toward candidate cells.

[0136] It will be appreciated that common to all of the procedures described above and shown in Figures 5- 8 is a method, carried out by a UE configured with a lower-layer triggered mobility configuration, where the method comprises the step of logging (and at least sometimes reporting) certain pre- synchronization-related information in response to an event associated to a mobility procedure. This information may include any of the following, for example:

[0137] • An indication of the activation / deactivation status of the one or more TCI states associated to the target cell of the mobility procedure.

[0138] • An indication of downlink pre-synchronization status associated to the target cell of the mobility procedure.

[0139] • An indication of uplink pre-synchronization status associated to the target cell. • One or more indications indicating the activation / deactivation status of the one or more TCI states associated to each of the one or more candidate cells.

[0140] • One or more indications indicating downlink pre-synchronization status associated to the one or more candidate cells.

[0141] • One or more indications indicating uplink pre-synchronization status associated to the one or more candidate cells.

[0142] • One or more indications indicating activation / deactivation status of the one or more TCI states associated to each of the one or more neighboring cells.

[0143] • One or more indications indicating downlink pre-synchronization status associated to the one or more neighboring cells.

[0144] • One or more indications indicating uplink pre-synchronization status associated to the one or more neighboring cells.

[0145] • An indication of the cell that activated the one or more TCI states associated to the cell in which the UE detected the event.

[0146] This information may be logged by the UE in a radio link failure report triggered upon failure of a mobility procedure. The failure of the mobility procedure may be due to a specific cause - the logging of this information may be in response to this specific cause. The failure of the mobility procedure may occur while operating in a beam with a TCI state activated by the source cell - the logging of the pre-synchronization related information may be triggered by this specific scenario.

[0147] Alternatively, the information described above may be logged by the UE in a radio link failure report triggered upon a failure after a successful mobility procedure, or in a radio link failure report triggered upon a failure before any mobility procedure while being configured with the candidate cells for the lower-layer triggered mobility operation, or in a successful handover report triggered upon a successful execution of mobility procedure. The successful handover report may be logged due to a specific cause occurred during the successful execution of the mobility procedure, in some instances or embodiments.

[0148] The mobility procedure may be a L3 (RRC) based reconfiguration with synch procedure such as normal handover (reconfigurationWithSynch) or a conditional handover (reconfigurationWithSynch) performed between source and target primary cell (so called PCell) or between source and target primary secondary cell (PSCell), or a Layer 1 or Layer 2 based mobility procedure so called LTM cell switch procedure performed between source and target primary cell (so called PCell) or between source and target primary secondary cell (PSCell). Indicating the activation / deactivation status of one TCI state associated to the cell (i.e., candidate, source, target, neighboring) may imply or include:

[0149] • Setting the state to 'activated' for the concerned cell if at least one TCI state was activated for the concerned cell at the time of detecting the event.

[0150] • Setting the state to 'deactivated' for the concerned cell if no TCI state was activated for the concerned cell at the time of detecting the event.

[0151] Alternatively or additionally, indicating the activation / deactivation status of one or more TCI states associated to the cell (i.e. candidate, source, target, neighboring) may imply or include:

[0152] • Setting the state to 'activated' for each of the active TCI states associated to the concerned cell at the time of detecting the event.

[0153] • Setting the state to 'deactivated' for each of the deactivated TCI states associated to the concerned cell if no TCI state was activated for the concerned cell at the time of detecting the event.

[0154] In some embodiments or instances, only the active TCI states associated to the cell (i.e., candidate, source, target, neighboring) are indicated.

[0155] The logged information may include an indication of pre-synchronization status for one or more cells and / or beams. Indicating the pre-synchronization status (uplink, downlink) of the cell (i.e. candidate, target, source neighboring) may imply or include:

[0156] • Setting the status to 'sync' for the concerned cell if the UE was synchronized to the concerned cell at the time of the event,

[0157] • Setting the status to 'unsynch' for the concerned cell if the UE was not synchronized to the concerned cell at the time of the event.

[0158] The logged information may include an indication of the cell that activated the one or more TCI states associated to the cell in which the UE detected the event. This may imply or include indicating the source cell identifier if the event was detected for a TCI state activated by the source cell of the mobility procedure. Alternatively or additionally, this may imply or include indicating the target cell identifier if the event was detected for a TCI state activated by the target cell of the mobility procedure.

[0159] According to various embodiments of the presently disclosed techniques, the UE logs and reports to a network, e.g., to a cell (served by a network node), information about pre-synchronization performed by the UE toward candidate cells of the mobility procedures. Pre-synchronization refers to any procedure (and / or steps in a procedure) in which the UE connected to a source cell is further configured with one or more candidate cell(s) for mobility, e.g., configured with LTM candidate cell (s). In that procedure (or in steps of that procedure) the UE synchronizes with one or of the candidate cells, e.g., based on a command from the network. This is called pre-synchronization because the UE synchronizes with one or more candidate cell(s) before the UE receives a mobility command. For example, in the case of LTM, the UE is configured with an LTM candidate, and before it receives an LTM cell switch command, while connected to the source cell, the UE synchronizes with the LTM candidate cell. This pre-synchronization may specifically refer to a TCI state activation / deactivation procedure (as specified in TS 38.321).

[0160] Examples of the logged information include, for example, candidate identifier(s) of candidate cells which the UE was synchronized with and / or beam identifiers of candidate cell (s) the UE was synchronized with and / or Reference Signal identifiers (e.g., SSB index or CSI-RS resource identity) of candidate cell(s) the UE was synchronized with, TCI state identifiers which were activated, for TCI states of a candidate cell, and / or TCI state identifiers which were deactivated, for TCI states of a candidate cell.

[0161] According to an example method, in a scenario with a LTM cell switch procedure, the UE is configured with a set of LTM candidate cells (e.g., received in an RRC Reconfiguration message), and TCI state configuration for at least one of the LTM candidate cell(s), and further receives at least one candidate cell TCI state activation (or deactivation) indication including an indication of the LTM candidate cell (e.g., candidate cell ID) for which the UE shall perform the pre-synchronization and a TCI state indication of at least one of the configured TCI state(s) of the indicated LTM candidate cell, indicating downlink and / or uplink TCI state indication representing the beam toward which the UE is to synchronize. Upon reception of the candidate TCI state activation, for example, the UE establishes a pre LTM cell switch synch toward the candidate target cell. The UE may later, e.g., upon a network request (e.g., LTM cell switch command) or upon fulfillment of some mobility execution conditions (e.g., conditional handover execution condition), execute a mobility procedure.

[0162] Following are some possible outcomes when the UE has been instructed to perform pre LTM cell switch synchronization toward a candidate cell:

[0163] A. In one scenario the UE performs the mobility procedure toward the candidate cell in which the TCI state activation was performed.

[0164] B. In another scenario the UE performs the mobility procedure toward a cell different than the candidate cell in which the TCI state activation was performed. This might happen due to the changes in the radio condition from the time network instructed the UE to activate the TCI state of the candidate cell to the time of execution of the mobility procedure.

[0165] C. In another scenario the the UE performs the mobility procedure toward the candidate cell in which the TCI state activation was performed but to a different TCI state for which the UE has not performed pre-sync, e.g., UE synchronized toward a different beam than the one it received in the candidate cell TCI activation command. That may be due to the fact that the indicated beam in the LTM cell switch command is not a beam previously indicated for DL pre-sync, or, in case the UE performs beam selection during a random access procedure in the LTM cell switch procedure and selects a beam not previously selected.

[0166] D. In another scenario, an RLF occurs, initiates a re-establishment procedure and, as part of that selects a cell and / or beam for which the UE has been DL synchronized.

[0167] E. In another scenario, an RLF occurs, initiates a re-establishment procedure and, as part of that selects a cell and / or beam for which the UE has NOT been DL synchronized.

[0168] Although scenario A is the expected behavior, scenario B, scenario C, D and E are also plausible, which may lead to sub-optimal performance, i.e., despite performing pre-synchronization toward a candidate cell the UE could not leverage the pre-synchronization feature as the UE needs to regain the synch either for a different target cell or a different target beam. This may lead to extra latency in a successful handover or may lead to a failure in handover execution or even failure after a successful execution of the mobility procedure.

[0169] According to an example method, the UE logs information pertaining to the above scenarios, in particular scenario B and scenario C in which the UE is in pre-synch with a cell but performs mobility toward another cell or a beam different from the beam indicated in the candidate cell TCI state activation command.

[0170] Example methods are described based on different scenarios in the following.

[0171] Logging pre-synchronization (e.g., TCI state activation status) in case of mobility procedure failure Following are details and variants of an example procedure for logging pre-synchronization-related information in the case of a mobility procedure failure. This is illustrated at a high level in Figure 6.

[0172] This procedure includes a step of receiving configurations indicating one or more candidate target cells for the mobility procedures (L3 reconfiguration with synch, so called handover, or LTM Cell Switch operation), from the serving RAN node (e.g., from the gNB-CU). This step is optional and may not exist in some mobility scenarios (e.g., normal Layer-3 based handover).

[0173] The procedure further includes a step of receiving configurations instructing the UE how to perform pre-synchronization toward one or more neighboring cells (e.g., toward candidate cells, using the candidate cell TCI state activation procedure, from the serving RAN node (e.g., from the gNB-DU). Note that these configurations are not commands to actually perform the pre-synchronization, but rather specifications of what a given pre-synchronization will involve, when invoked.

[0174] For example, in the case the mobility procedure relates to LTM, the UE receives an LTM configuration (IE LTM-Config) in an RRC Reconfiguration message, which includes a list of configuration(s) per LTM candidate cell to be added or modified, e.g., Itm-CandidateToAddModList-rlS of IE SEQUENCE (SIZE (l..maxNrofLTM-Configs-rl8)) OF LTM-Candidate-rl8. Each configuration per LTM candidate cell (e.g., in the IE LTM-Candidate-rl8) may include TCI state configuration(s) for the respective LTM candidate cell (associated to the IE LTM-Candidateld-rl8), including TCI state(s) that may be pre-activated (i.e. activated before the LTM cell switch command is received by the UE) or further deactivated. The TCI state configuration(s) within the configuration per LTM candidate may correspond to one or more of the following:

[0175] A list of TCI states for LTM to add and / or modify, e.g., encoded as Itm-DL-OrJointTCI- StateToAddModList-rl8 SEQUENCE (SIZE (l..maxNrofCandidateTCI-State-rl8)) OF CandidateTCI-State-rl8; o Each TCI state for LTM configuration may correspond to the IE CandidateTCI-State and defines a TCI states configuration which associate one or more reference signal with a corresponding quasi-colocation (QCL) type.

[0176] A list of uplink TCI states for LTM to add and / or modify, e.g., encoded as Itm-UL-TCI- StatesToAddModList-rl8 SEQUENCE (SIZE (l..maxNrofCandidateUL-TCI-rl8)) OF CandidateTCI-UL-State-rl8; o Each TCI state for LTM configuration may correspond to th IE CandidateTCI-UL-State;

[0177] Each TCI state configuration (e.g., in the IE CandidateTCI-State) defines a TCI state configuration which associate one or more reference signal with a corresponding quasi-colocation (QCL) type and may include:

[0178] TCI state identity (tci-Stateld-rl8 of IE TCI-Stateld);

[0179] - QCL type 1 (qcl-Typel-rl8 of IE LTM-QCL-lnfo-rl8); o Including an RS index, e.g., SSB index or CSI-RS index;

[0180] - QCL type 2 (qcl-Type2-rl8 of IE LTM-QCL-lnfo-rl8) o Including an RS index, e.g., SSB index or CSI-RS index;

[0181] Path loss reference RS (pathlossReferenceRS-ld-rl8 of PathlossReferenceRS-ld-rl7).

[0182] The procedure further comprises performing TCI state activation (so-called pre-synchronization) toward one or more cells indicated in the one or more candidate cell TCI activation indication, and being synched with the one or more cells. Synchronization may be done in uplink or downlink or both uplink and downlink. Performing may be based on the reception of an activation command from the network to the UE. In the case of LTM that may be a "Candidate Cell TCI States Activation / Deactivation MAC CE".

[0183] In some cases, after the UE has activated a TCI state of an LTM candidate cell, the UE may deactivate that TCI state, e.g., upon reception of another network command, e.g., another "Candidate Cell TCI States Activation / Deactivation MAC CE", indicating deactivation. In that case, the UE can log a sequence of activation / deactivation events, to be later reported in the SON report. For example, if for cell A the UE at to received a command to activate TCI state whose TCI state ID=x, and at tl the UE receives a command to deactivate TCI state whose TCI state ID=x, and at t2 the UE receives a command to activate the TCI state whose TCI state ID=x again, the UE keeps track of the different status and / or status changes and may log a sequence of status for the TCI state ID=x the, e.g., ['activated', 'deactivated', 'activated']; or, something derived from it or equivalent, such as the number of times a status change occurred combined with the current state, e.g., for the previous example the status has changed 3 times (starting as deactivated) and the status at the time of the event (failure of successful mobility execution) was activated. Performing the mobility procedure toward a target cell, either upon receiving an indication from the network node (e.g., from the gNB- CU for the L3 handover or from the gNB-DU for the LTM cell switch) to perform a mobility operation toward a target cell, or upon fulfillment of execution conditions associated to a conditional mobility configuration (CHO configuration or conditional LTM cell switch configuration).

[0184] In this example scenario, the procedure further comprises the step of declaring a radio link failure upon execution of the mobility procedure and logging and RLF report with the information pertaining to the detected failure. This includes Including the information associated to the pre-synchronization (such as TCI activation status) of one or more candidate cells in the RLF report., e.g., candidate cell identifier for a cell for which the UE has performed pre-synchronization and / or associated TCI state which is activated and / or deactivated. In some embodiments or instances, the UE logs the pre-synchronization status (e.g., TCI activation status) of the cells which were activated when the UE detects the failure in the mobility execution procedure (Timer T304 expiry), associated with a candidate cell identifier.

[0185] • For example, in the case of LTM, when cell A is an LTM candidate cell for which the UE was pre-synchronized when the failure was detected, the UE logs cell A's LTM-Candidateld and its status set to 'sync', or something equivalent, e.g., a list of LTM-Candidateld(s) of candidate cells for which the UE was synchronized.

[0186] • For example, in the case of LTM, when cell A is an LTM candidate cell for which the UE had at least one TCI state activated, when the failure was detected, the UE logs cell A's LTM- Candidateld and the status set to 'activated', or something equivalent, e.g., a list of LTM- Candidateld(s) of candidate cells for which the UE had at least one activated TCI state.

[0187] • For example, in the case of LTM, when cell A is an LTM candidate cell for which TCI states whose TCI state ID=x and TCI state I D=y were activated when the failure was detected, the UE logs cell A's LTM-Candidateld and the status set per configured TCI state, e.g., set to 'activated' for the activated TCI states; or something equivalent, e.g., a list of LTM- Candidateld(s) of candidate cells for which the UE had at least one acticated TCI state, and for cell the status of the configured TCI states or, a list of TCI state I D(s) for the TCI states which were activated.

[0188] In some embodiments or instances, the UE logs the pre-sync information for a candidate cell depending on the target cell and / or target beam indicated in the mobility command, e.g., LTM candidate ID and TCI state Id in the LTM cell switch command. For example:

[0189] • The UE may log the pre-synchronization status (e.g., TCI activation status) of the cells in the case the target cell toward which the mobility procedure is executed is not among the set of one or more cells toward which the UE was pre-synchronized and activated the TCI states. This means that before logging the information UE determines whether the target cell toward which the mobility procedure is executed (e.g., LTM candidate ID indicated in LTM cell switch) is or is not among the set of one or more cells toward which the UE was pre-sync and activated the TCI states. The logic here is that the network only gets a report when its decision was sub-optimal, so a lack of report indicates the decisions were fine, i.e., UE ends up in a cell for which it was previously synchronized with.

[0190] • The UE may log the pre-synchronization status (e.g., TCI activation status) of the cells in the case the target beam (e.g., TCI state indicated in the LTM cell switch command) towards which the mobility procedure is executed is not among the set of activated TCI states of that target cell i.e., the UE logs pre-synchronization information (e.g., TCI activation status) when the received TCI state in the candidate cell TCI state activation command is different from the TCI state of the UE upon execution of the mobility procedure toward the target cell. This means that before logging the information UE determines whether the target beam towards which the mobility procedure is executed (e.g., TCI state ID of the LTM candidate ID indicated in LTM cell switch) is or is not among the set of TCI states which were activated. The logic here is that the network only gets a report when its decision was sub-optimal, so a lack of report indicates the decisions were fine, i.e., UE ends up in a cell for which it was previously synchronized with.

[0191] In other embodiments or instances, the UE logs an indication associated to the target cell, the indication indicates whether the UE has performed synchronization toward the target cell at the time of execution of the mobility procedure, e.g., at the time of the handover.

[0192] In some embodiments or instances, the UE logs the pre-synchronization status (e.g., TCI activation status) of the cells for which a TCI state has been activated or deactivated when the UE detects the failure in the mobility execution procedure. For example:

[0193] • The UE may log, for a cell (e.g., target cell, candidate cells configured by the source cells, neighboring cells configured for RRM measurements by the source cell) identifier, the list of TCI states which are currently "activated" and, at the same time, another list of TCI states which are currently as "deactivated". In this case, a "deactivated" TCI state is a TCI state which was initially activated and later deactivated by the reception of the TCI activated / deactivated MAC CE.

[0194] • The UE may log only the TCI states that were active at the time of detecting the failure. For example, only the TCI states that were active in the cell in which the failure was detected after completing the mobility procedure

[0195] • The UE may log the TCI states as active and / or inactive only if they were configured by the source cell of the mobility procedure.

[0196] • The UE may log the TCI states as active and / or inactive irrespective of whether they were configured by the source cell or by target cell of the mobility procedure. In such case, the UE may log in correspondence of a TCI state an indication of the cell identifier of the cell that configured the said TCI state.

[0197] • The UE may log an indication associated to the target cell, the indication indicates whether the UE has already activated the candidate cell TCI state toward the target cell at the time of execution of the handover. • The UE may log an indication associated to the target cell, the indication indicates whether the UE has already activated the candidate cell downlink TCI state toward the target cell at the time of execution of the handover.

[0198] • The UE may log an indication associated to the target cell, the indication indicates whether the UE has already activated the candidate cell uplink TCI state toward the target cell at the time of execution of the handover.

[0199] • The UE may log an indication associated to the target cell, the indication indicates whether the UE has already activated the candidate cell both downlink and uplink TCI state toward the target cell at the time of execution of the handover.

[0200] • The UE may log the above mentioned indication for each and every neighboring cells or each and every candidate cell.

[0201] In some embodiments or instances, the logging of the above indications depends on the cause of the failure. For example, the logging of the above indications is only performed if the failure is due to a beam failure recovery procedure following a beam failure.

[0202] • This handles the case in which the radio link failure is detected in the target cell of the mobility procedure, but that failure is not due to operations related to the TCI states configured as part of the LTM procedure. For example, if the failure is due to random access problems in the target cell, or to consistent listen before talk failures, then no information associated to the TCI states configured for the LTM procedure should be logged.

[0203] In some embodiments or instances, in a case where the failure is due to a beam failure recovery procedure, the UE only logs the TCI state associated to the beam in which the beam failure was detected. In another example, if the beam failure was detected for a beam whose associated TCI state was configured or activated or deactivated by the source, the UE logs the TCI status of the concerned beam, otherwise it does not. In yet another example, the UE logs the cell that configured or activated or deactivated the beam, i.e., the source cell identifier or the target cell identifier

[0204] • This handles the cases in which the radio link failure is detected after a successful handover.

[0205] In some cases, the failure may occur due to failures occurred in beams whose TCI state was configured and possibly activated by the source cell of the mobility procedure. In some other cases, instead the the failure may occur due to failures occurred in beams whose TCI state was activated by the target cell of the mobility procedure after the successful handover

[0206] The steps discussed above may be followed by the UE reporting, to the network, the logged report including the information and / or measurements related to the pre-synchronization toward candidate cells. Logging pre-synchronization (e.g., TCI state activation status) in case ofRLF after a successful mobility procedure

[0207] Following are details and variants of an example procedure for logging pre-synchronization-related information in the case of a radio link failure that occurs after a successful mobility procedure. This is illustrated at a high level in Figure 7.

[0208] This procedure includes a step of receiving configurations indicating one or more candidate target cells for the mobility procedures (L3 reconfiguration with synch, so called handover, or LTM Cell Switch operation), from the serving RAN node (e.g., from the gNB-CU). This step is optional and may not exist in some mobility scenarios (e.g., normal Layer-3 based handover).

[0209] The procedure further includes a step of receiving configurations instructing the UE to perform presynchronization toward one or more neighboring cells (e.g., toward candidate cells, using the candidate cell TCI state activation procedure, from the serving RAN node (e.g., from the gNB-DU). Again, these configurations are not commands to actually perform the pre-synchronization, but rather specifications of what a given pre-synchronization will involve, when invoked.

[0210] The procedure further includes the step of performing TCI state activation (so-called presynchronization) toward one or more cells indicated in the one or more candidate cell TCI activation indication, and being synched with the one or more cells. Synchronization may be done in uplink or downlink or both uplink and downlink. This performing may be based on the reception of an activation command from the network to the UE. In the case of LTM that may be a "Candidate Cell TCI States Activation / Deactivation MAC CE".

[0211] The procedure still further comprises performing a mobility procedure toward a target cell, either upon receiving an indication from the network node (e.g., from the gNB-CU for the L3 handover or from the gNB-DU for the LTM cell switch) to perform a mobility operation toward a target cell, or upon fulfillment of execution conditions associated to a conditional mobility configuration (CHO configuration or conditional LTM cell switch configuration).

[0212] In this scenario, the procedure comprises the step of declaring a radio link failure in the target cell. In this scenario, this occurs after successful execution and completion of the mobility procedure. The procedure further comprises logging an RLF report with pre-synchronization information pertaining to the detected failure. This may comprise including information associated to the presynchronization and TCI state activation status of one or more cells in the RLF report. In some embodiments or instances, the UE logs the pre-synchronization status and TCI activation status of the cells only if the target cell toward which the mobility procedure is executed is not among the set of one or more cells toward which the UE was pre-synchronized and activated the TCI states.

[0213] In other embodiments or instances, the UE logs the pre-synchronization status and TCI activation status of the cells only if the target beam toward which the mobility procedure is executed is not among the set of activated TCI state of that target cell, i.e., the logs pre-synchronization and TCI activation status if the received TCI state in the candidate cell TCI state activation command is different from the TCI state of the UE upon execution of the mobility procedure toward the target cell.

[0214] In other embodiments or instances, the UE logs an indication associated to the target cell, the indication indicates whether the UE has performed synchronization toward the target cell at the time of execution of the handover.

[0215] In still other embodiments or instances, the UE logs the pre-synchronization status (e.g., TCI activation status) of the cells for which a TCI state has been activated or deactivated when the UE successfully completed the mobility execution procedure. For example:

[0216] • The UE may log, for a candidate cell identifier, the list of TCI states which are currently "activated" and, at the same time, another list of TCI states which are currently as "deactivated". In this case, a "deactivated" TCI state is a TCI state which was initially activated and later on deactivated by the reception of the TCI activated / deactivated MAC CE.

[0217] In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicating whether the UE has already activated the candidate cell TCI state toward the target cell at the time of execution of the handover.

[0218] In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicating whether the UE has already activated the candidate cell downlink TCI state toward the target cell at the time of execution of the handover.

[0219] In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicating whether the UE has already activated the candidate cell uplink TCI state toward the target cell at the time of execution of the handover. In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicates whether the UE has already activated the candidate cell both downlink and uplink TCI state toward the target cell at the time of execution of the handover.

[0220] In some embodiments or instances, the UE logs the above-mentioned indication for each and every neighboring cell or each and every candidate cell.

[0221] The procedure may further comprise reporting, to the network, the logged report including the information and / or measurements related to the pre-synchronization toward candidate cells.

[0222] Logging pre-synchronization and TCI state activation status in case of generating successful handover report upon successful execution of mobility procedure

[0223] Following are details and variants of an example procedure for logging pre-synchronization-related information in the case of a successful mobility procedure. This is illustrated at a high level in Figure 8.

[0224] This procedure also includes a step of receiving configurations indicating one or more candidate target cells for the mobility procedures (L3 reconfiguration with synch, so called handover, or LTM Cell Switch operation), from the serving RAN node (e.g., from the gNB-CU). This step is optional and may not exist in some mobility scenarios (e.g., normal Layer-3 based handover).

[0225] The procedure further includes a step of receiving configurations instructing the UE to perform presynchronization toward one or more neighboring cells (e.g., toward candidate cells, using the candidate cell TCI state activation procedure, from the serving RAN node (e.g., from the gNB-DU). Again, these configurations are not commands to actually perform the pre-synchronization, but rather specifications of what a given pre-synchronization will involve, when invoked.

[0226] The procedure further includes the step of performing TCI state activation (so-called presynchronization) toward one or more cells indicated in the one or more candidate cell TCI activation indication, and being synched with the one or more cells. Synchronization may be done in uplink or downlink or both uplink and downlink. This performing may be based on the reception of an activation command from the network to the UE. In the case of LTM that may be a "Candidate Cell TCI States Activation / Deactivation MAC CE".

[0227] The procedure still further comprises performing a mobility procedure toward a target cell, either upon receiving an indication from the network node (e.g., from the gNB-CU for the L3 handover or from the gNB-DU for the LTM cell switch) to perform a mobility operation toward a target cell, or upon fulfillment of execution conditions associated to a conditional mobility configuration (CHO configuration or conditional LTM cell switch configuration).

[0228] In this scenario, the UE successfully executes the mobility procedure toward the target cell, and the procedure comprises logging a successful handover report (SHR), e.g., upon fulfilment of one or more SHR triggering conditions.

[0229] In some embodiments or instances, the SHR triggering condition can be a flag configured by the network to indicate the UE to log the SHR, in cae the target cell is different from the one or more cells the UE activated the TCI state toward it i.e, the UE was in synch with some other cells than the one that the UE successfully executed the handover.

[0230] This example procedure comprises the step of including information associated to the presynchronization and TCI state activation status of one or more cells in the SHR.

[0231] In some embodiments or instances, the UE logs the pre-synchronization status and TCI activation status of the cells only if the target cell toward which the mobility procedure is executed is not among the set of one or more cells toward which the UE was pre-synchronized and activated the TCI states.

[0232] In some embodiments or instances, the UE logs the pre-synchronization status and TCI activation status of the cells only if the target beam toward which the mobility procedure is executed is not among the set of activated TCI state of that target cell, i.e., the logs pre-synchronization and TCI activation status if the received TCI state in the candidate cell TCI state activation command is different from the TCI state of the UE upon execution of the mobility procedure toward the target cell.

[0233] In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicates whether the UE has performed synchronization toward the target cell at the time of execution of the handover

[0234] In some embodiments or instances, the UE logs the pre-synchronization status (e.g., TCI activation status) of the cells for which a TCI state has been activated or deactivated. For example:

[0235] • The UE may log, for a candidate cell identifier, the list of TCI states which are currently "activated" and, at the same time, another list of TCI states which are currently as "deactivated". In this case, a "deactivated" TCI state is a TCI state which was initially activated and later on deactivated by the reception of the TCI activated / deactivated MAC CE. In other embodiments or instances, the UE logs an indication associated to the target cell, the indication indicates whether the UE has already activated the candidate cell TCI state toward the target cell at the time of execution of the handover.

[0236] In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicating whether the UE has already activated the candidate cell downlink TCI state toward the target cell at the time of execution of the handover.

[0237] In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicating whether the UE has already activated the candidate cell uplink TCI state toward the target cell at the time of execution of the handover.

[0238] In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicating whether the UE has already activated the candidate cell both downlink and uplink TCI state toward the target cell at the time of execution of the handover. n some embodiments or instances, the UE logs the above-mentioned indication for each and every neighboring cells or each and every candidate cells

[0239] The procedure may further comprise reporting, to the network, the logged successful handover report including the information and / or measurements related to the pre-synchronization toward candidate cells.

[0240] Logging pre-synchronization (e.g., TCI state activation status) in case ofRLFin source, before a mobility procedure is triggered.

[0241] Another possible scenario is that radio link failure (RLF) occurs while the UE is connected to its source cell, before a mobility procedure is triggered. In this case the UE may log information like that described above in a radio link failure report, and include in the report the information (e.g., one or more candidate cell identifiers) and / or measurements (e.g., latest available) related to the presynchronization toward candidate cells (i.e., information related to the candidate target cells TCI state activation / deactivation), when an RLF occurs in a source cell before a mobility procedure is triggered, e.g., before the UE receives an LTM cell switch command, but after the UE has received a command to activate a TCI state of an LTM candidate cell.

[0242] In this case, the UE may either initiate a re-establishment procedure to a cell for which the UE had performed pre-synchronization, or to a cell for which the UE had not performed pre-synchronization. And, the initiation of the re-establishment may lead to a successful mobility procedure (e.g .Conditional Handover execution, or LTM cell switch) or the continuation of a re-establishment procedure (i..e the UE transmitting an RRC Reestablishment Request message, receiving an RRC Reestablishment in response and transmitting an RRC Reestablishment Complete).

[0243] In this scenario, then, the procedure may include the step of receiving configurations indicating one or more candidate target cells for the mobility procedures (L3 reconfiguration with synch, so called handover, or LTM Cell Switch operation), from the serving RAN node (e.g., from the gNB-CU). This step is optional and may not exist in some mobility scenarios (e.g., normal Layer-3 based handover).

[0244] The procedure further includes a step of receiving configurations instructing the UE to perform presynchronization toward one or more neighboring cells (e.g., toward candidate cells, using the candidate cell TCI state activation procedure, from the serving RAN node (e.g., from the gNB-DU). Again, these configurations are not commands to actually perform the pre-synchronization, but rather specifications of what a given pre-synchronization will involve, when invoked.

[0245] For example, in the case the mobility procedure relates to LTM, the UE may receive an LTM configuration (IE LTM-Config) in an RRC Reconfiguration message, which includes a list of configuration(s) per LTM candidate cell to be added or modified, e.g., Itm-CandidateToAddModList- rl8 of IE SEQUENCE (SIZE (l..maxNrofLTM-Configs-rl8)) OF LTM-Candidate-rl8. Each configuration per LTM candidate cell (e.g., in the IE LTM-Candidate-rl8) may include TCI state configuration(s) for the respective LTM candidate cell (associated to the IE LTM-Candidateld-rl8), including TCI state(s) that may be pre-activated (i.e. activated before the LTM cell switch command is received by the UE) or further deactivated. The TCI state configuration(s) within the configuration per LTM candidate may correspond to one or more of the following:

[0246] A list of TCI states for LTM to add and / or modify, e.g., encoded as Itm-DL-OrJointTCI- StateToAddModList-rl8 SEQUENCE (SIZE (l..maxNrofCandidateTCI-State-rl8)) OF CandidateTCI-State-rl8; o Each TCI state for LTM configuration may correspond to the IE CandidateTCI-State and defines a TCI states configuration which associate one or more reference signal with a corresponding quasi-colocation (QCL) type.

[0247] A list of uplink TCI states for LTM to add and / or modify, e.g., encoded as Itm-UL-TCI- StatesToAddModList-rl8 SEQUENCE (SIZE (l..maxNrofCandidateUL-TCI-rl8)) OF CandidateTCI-UL-State-rl8; o Each TCI state for LTM configuration may correspond to the IE CandidateTCI-UL- State; Each TCI state configuration (e.g., in the IE CandidateTCI-State) defines a TCI state configuration which associate one or more reference signal with a corresponding quasi-colocation (QCL) type and may include:

[0248] TCI state identity (tci-Stateld-rl8 of IE TCI-Stateld);

[0249] - Q.CL type 1 (qcl-Typel-rl8 of IE LTM-Q.CL-lnfo-rl8); o Including an RS index, e.g., SSB index or CSI-RS index;

[0250] - Q.CL type 2 (qcl-Type2-rl8 of IE LTM-Q.CL-lnfo-rl8) o Including an RS index, e.g., SSB index or CSI-RS index;

[0251] Path loss reference RS (pathlossReferenceRS-ld-rl8 of PathlossReferenceRS-ld-rl7).

[0252] The procedure may further include the step of performing TCI state activation (so-called presynchronization) toward one or more cells indicated in the one or more candidate cell TCI activation indication, and becoming synched with the one or more cells. Synchronization may be done in uplink or downlink or both uplink and downlink. This performing may be based on the reception of an activation command from the network to the UE. In the case of LTM that may be a "Candidate Cell TCI States Activation / Deactivation MAC CE".

[0253] In some embodiments or instances, after the UE has activated a TCI state of an LTM candidate cell, the UE may deactivate that TCI state, e.g., upon reception of another network command, e.g., another "Candidate Cell TCI States Activation / Deactivation MAC CE", indicating deactivation, before an RLF occurs (e.g., expiry of timer T310, maximum number of random access attempts is reached). In that case, the UE can log a sequence of activation / deactivation events, to be later reported in the SON report. For example, if for cell A the UE at to received a command to activate TCI state whose TCI state ID=x, and at tl the UE receives a command to deactivate TCI state whose TCI state ID=x, and at t2 the UE receives a command to activate the TCI state whose TCI state ID=x again, the UE keeps track of the different status and / or status changes and may log a sequence of status for the TCI state ID=x the, e.g., ['activated', 'deactivated', 'activated']; or, something derived from it or equivalent, such as the number of times a status change occurred combined with the current state, e.g., for the previous example the status has changed 3 times (starting as deactivated) and the status at the time of the event (failure of successful mobility execution) was activated.

[0254] In this scenario, the procedure may comprise the steps of the UE declaring a RLF in the source cell and logging an RLF report with information pertaining to the detected failure, the information comprising information associated to the pre-synchronization (such as TCI activation status) of one or more candidate cells in the RLF report, e.g., candidate cell identifier for a cell for which the UE has performed pre-synchronization and / or associated TCI state which is activated and / or deactivated. The information associated to the pre-synchronization (such as TCI activation status) of one or more candidate cells in the RLF report., e.g., candidate cell identifier for a cell for which the UE has performed pre-synchronization and / or associated TCI state which is activated and / or deactivated may be included in the RLF report, which may later be sent to the network.

[0255] In some embodiments or instances, the UE may log the pre-synchronization status (e.g., TCI activation status) of the cells which were activated when the UE detects the failure in the mobility execution procedure (Timer T304 expiry), associated with a candidate cell identifier.

[0256] • For example, in the case of LTM, when cell A is an LTM candidate cell for which the UE was pre-synchronized when the failure was detected, the UE logs cell A's LTM-Candidateld and its status set to 'sync', or something equivalent, e.g., a list of LTM-Candidateld(s) of candidate cells for which the UE was synchronized.

[0257] • For example, in the case of LTM, when cell A is an LTM candidate cell for which the UE had at least one TCI state activated, when the failure was detected, the UE logs cell A's LTM- Candidateld and the status set to 'activated', or something equivalent, e.g., a list of LTM- Candidateld(s) of candidate cells for which the UE had at least one activated TCI state.

[0258] • For example, in the case of LTM, when cell A is an LTM candidate cell for which TCI states whose TCI state ID=x and TCI state I D=y were activated when the failure was detected, the UE logs cell A's LTM-Candidateld and the status set per configured TCI state, e.g., set to 'activated' for the activated TCI states; or something equivalent, e.g., a list of LTM- Candidateld(s) of candidate cells for which the UE had at least one activated TCI state, and for cell the status of the configured TCI states or, a list of TCI state I D(s) for the TCI states which were activated.

[0259] In some embodiments or instances, the UE logs the pre-sync information for a candidate cell depending on the target cell and / or target beam indicated in the mobility command, e.g., LTM candidate ID and TCI state Id in the LTM cell switch command. For example:

[0260] • The UE may log the pre-synchronization status (e.g., TCI activation status) of the cells in the case the target cell toward which the mobility procedure is executed is not among the set of one or more cells toward which the UE was pre-synchronized and activated the TCI states. This means that before logging the information UE determines whether the target cell toward which the mobility procedure is executed (e.g., LTM candidate ID indicated in LTM cell switch) is or is not among the set of one or more cells toward which the UE was pre-sync and activated the TCI states. The logic here is that the network only gets a report when its decision was sub-optimal, so a lack of report indicates the decisions were fine, i.e., UE ends up in a cell for which it was previously synchronized with.

[0261] • The UE may log the pre-synchronization status (e.g., TCI activation status) of the cells in the case the target beam (e.g., TCI state indicated in the LTM cell switch command) towards which the mobility procedure is executed is not among the set of activated TCI states of that target cell i.e., the UE logs pre-synchronization information (e.g., TCI activation status) when the received TCI state in the candidate cell TCI state activation command is different from the TCI state of the UE upon execution of the mobility procedure toward the target cell. This means that before logging the information UE determines whether the target beam towards which the mobility procedure is executed (e.g., TCI state ID of the LTM candidate ID indicated in LTM cell switch) is or is not among the set of TCI states which were activated. The logic here is that the network only gets a report when its decision was sub-optimal, so a lack of report indicates the decisions were fine, i.e., UE ends up in a cell for which it was previously synchronized with.

[0262] In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicates whether the UE has performed synchronization toward the target cell at the time of execution of the mobility procedure, e.g., at the time of the handover.

[0263] In some embodiments or instances, the UE logs the pre-synchronization status (e.g., TCI activation status) of the cells for which a TCI state has been activated or deactivated. For example:

[0264] • The UE may log, for a candidate cell identifier, the list of TCI states which are currently "activated" and, at the same time, another list of TCI states which are currently as "deactivated". In this case, a "deactivated" TCI state is a TCI state which was initially activated and later on deactivated by the reception of the TCI activated / deactivated MAC CE.

[0265] In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicates whether the UE has already activated the candidate cell TCI state toward the target cell at the time of execution of the handover.

[0266] In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicating whether the UE has already activated the candidate cell downlink TCI state toward the target cell at the time of execution of the handover. In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicating whether the UE has already activated the candidate cell uplink TCI state toward the target cell at the time of execution of the handover.

[0267] In some embodiments or instances, the UE logs an indication associated to the target cell, the indication indicating whether the UE has already activated the candidate cell both downlink and uplink TCI state toward the target cell at the time of execution of the handover.

[0268] In some embodiments or instances, the UE logs the above-mentioned indication for each and every neighboring cell or each and every candidate cell.

[0269] The example procedure may include sending, to the network, the logged report including the information and / or measurements related to the pre-synchronization toward candidate cell.

[0270] Although much of the discussion herein has focused on TCI state activation or deactivation commands that pertain to downlink pre-synchronization, the techniques described herein are more generally applicable to commands instructing the UE to perform downlink and / or uplink presynchronization or informing the UE that this synchronization is no longer needed, for a given beam and / or cell. Thus, the command may be a TCI state activation / deactivation for a DL or UL, or for a joint UL and DLTCI state.

[0271] In particular examples, the synchronization procedure according to the TCI state activation / deactivation indication or command is for acquiring DL synchronization to the corresponding beam of a cell.

[0272] In some embodiments, or instances, the TCI state activation / deactivation command may be represented by the Candidate Cell TCI States Activation / Deactivation MAC CE. The subsequent LTM cell switch command, in the context of Ll / L2-triggered mobility (LTM), may be represented by the LTM cell switch MAC CE.

[0273] As seen in the above examples, then, in various embodiments and instances of the presently disclosed techniques, a UE (a term that is used herein to refer generally to a wireless access terminal for operating in a wireless network, whether or not it is a 3GPP wireless access terminal) logs and reports to a network, e.g., to a cell served by a network node, information relating to presynchronization performed by the UE toward candidate cells of the mobility procedures. Presynchronization refers to any procedure (and / or steps in a procedure) in which a UE connected to a source cell is further configured with one or more candidate cell(s) for mobility, e.g., configured with LTM candidate cell (s) and, in that procedure (or in steps of that procedure) the UE synchronizes with one or of the candidate cells, e.g., based on a command from the network. This is called presynchronization because the UE synchronizes with one or more candidate cell(s) before the UE receives a mobility command. For example, in the case of LTM, the UE is configured with an LTM candidate, and before it receives an LTM cell switch command, while connected to the source cell, the UE synchronizes with the LTM candidate cell.

[0274] The term "beam" may be utilized to represent a TCI state. A TCI state may be associated to a Reference Signal (RS), e.g., Synchronization Signal Block (SSB), wherein the RS is configured as Quasi- co-located (QCL) source of the TCI state, and the RS is transmitted in a spatial direction (beam). Thus, activating a TCI state may comprise synchronizing with the RS configured as a QCL source of the TCI state, where the RS is transmitted in a beam. Thus, when this document describes a beam of a target cell, that may directly correspond to a TCI state of the target (LTM candidate) cell and / or a RS configured as QCL source of the TCI state.

[0275] Any of various ones of the information elements described above may be logged by the UE, in response to any of the following events:

[0276] • Successful completion of the mobility procedure. In which case the information may be logged in the SHR (if the mobility procedure is for the change of the PCell, i.e., classical HO), or in the SPR (if the mobility procedure is for the addition or change of the PSCell).

[0277] • Radio link failure during the mobility procedure execution. In this case, the information may be logged in the RLF-Report.

[0278] • Radio link failure before the mobility procedure was executed and the UE was configured with LTM candidate cells. In this case, the information may be logged in the RLF-Report.

[0279] • Radio link failure after the mobility procedure was executed, i.e., the failure occurs in the target cell. In this case, the information may be logged in the RLF-Report.

[0280] The above information may be logged in response to any of the above events as long as certain conditions are met, in some embodiments or instances. For example, the information may be logged only in case the mobility procedure is executed towards a beam of the target cell for which the TCI state activation was received while the UE was connected to the source cell, i.e., the UE executes the cell switch according to the LTM cell switch MAC CE indicating the target cell and a corresponding TCI state for which the UE received previous in the source cell the Candidate Cell TCI States Activation / Deactivation MAC CE for the said target cell and TCI state, i.e., the UE was requested by the source cell to synchronize to the beam according the said TCI state for the target cell.

[0281] In another case, the above information are logged only in the case the failure after successfully completing the mobility procedure occurs while the UE was operating on the same TCI state configured by the source cell during the mobility procedure, i.e. failure while operating on the TCI state indicated in the LTM cell switch MAC CE for the target cell.

[0282] In view of the detailed examples given above, it should be understood that Figure 9 is a process flow illustrating an example method carried out by a UE or other wireless terminal operating in a wireless network. The illustrated method is intended to be a generalization of the UE-related techniques described above - hence, where terminology used to describe the method of Figure 9 differs in some respects from similar or related terminology used above, the former should be understood to at least encompass the latter, unless the context clearly indicates otherwise. Further, it should be appreciated that while the following discussion describes certain variations or specific examples of the illustrated method, the method in its broadest conception is not limited to these variations or specific examples.

[0283] As shown at block 910, the method includes the step of receiving, from the wireless network, a command instructing the UE to perform downlink pre-synchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed. As discussed above, this command may be a TCI state activation or deactivation command, in some embodiments. The method further comprises, as shown at block 920, the step of subsequently logging, in response to a successful change or addition of cell or in response to a failed mobility procedure, information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in the command. This information may, in particular, relate to the presynchronization status of one or more cells and / or beams.

[0284] In some embodiments or instances, the method further comprises transmitting the logged information to the wireless network. This is shown at block 950. The method may comprise, prior to this transmitting, sending an indication of the availability of the logged information to the wireless network, as shown at block 930, where the transmitting is in response to receipt of a request for the logged information, e.g., as shown at block 940.

[0285] As noted above, in some embodiments or instances, the command received by the UE is a TCI state activation command or a TCI state deactivation command. In some embodiments or instances, the successful change or addition of cell or failed mobility procedure that triggers the logging is triggered by a Layer 1 / Layer 2-triggered Mobility (LTM) cell switch command. In others, the successful change or addition of cell or failed mobility procedure may be triggered by a Layer 3-based reconfiguration or conditional handover. In various embodiments or instances, the logged information may comprise any of the following: an indication of activation / deactivation status of each of one or more TCI states associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of downlink presynchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of uplink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; one or more indications of the activation / deactivation status of the one or more TCI states associated to each of one or more candidate cells for mobility; one or more indications indicating downlink pre-synchronization status associated to one or more candidate cells for mobility; one or more indications indicating uplink presynchronization status associated to one or more candidate cells for mobility; one or more indications indicating activation / deactivation status of one or more TCI states associated to each of one or more neighboring cells; one or more indications indicating downlink pre-synchronization status associated to one or more neighboring cells; one or more indications indicating uplink presynchronization status associated to one or more neighboring cells; and an indication of a cell that activated one or more TCI states associated to the cell in which the UE detected an event triggering the logging. These are non-limiting examples - the discussion above provides additional examples as well as details and variations of these.

[0286] In some embodiments or instances, the logging is responsive to execution of a mobility procedure towards a beam of a target cell for which TCI state activation was received while the UE was connected to a source cell for the mobility procedure. In some embodiments or instances, at least some of the logged information is timing-related information related to a last TCI state activation command or last TCI state deactivation received by the UE while the UE was connected to a source cell prior to a mobility procedure execution.

[0287] In some embodiments or instances, the method includes including the logged information in a radio link failure report. The radio link failure report may be one that that is triggered (by a radio link failure) sometime after a successful mobility procedure following reception of the command, in some embodiments or instances.

[0288] In some embodiments or instances, the method instead includes including the logged information in a successful handover report.

[0289] Figure 10 is a process flow diagram illustrating an example method performed in a network node, such as a gNB, operating in a wireless network. Again, the illustrated method, which complements the UE-based methods described above, is intended to be a generalization of the network node- related techniques described above - hence, where terminology used to describe the method of Figure 10 differs in some respects from similar or related terminology used above, the former should be understood to at least encompass the latter, unless the context clearly indicates otherwise.

[0290] As shown at block 1030, the method comprises receiving, from a user equipment (UE), a report of a successful or unsuccessful mobility event or of a radio link failure, the report comprising information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in a command from the wireless network instructing the UE to perform downlink pre-synchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed, the information having been logged by the UE in response to a subsequent successful change or addition of cell or failed mobility procedure.

[0291] In some embodiments or instances, the method comprises receiving the report in response to a request for the report sent to the UE, e.g., as shown at block 1020. This sending of the request for the report may in turn be in response to receiving, from the UE, an indication that the report is available, as shown at block 1010.

[0292] In some embodiments or instances, the command referred to above is a TCI state activation command or a TCI state deactivation command. In some embodiments or instances, the successful change or addition of cell or failed mobility procedure is triggered by a Layer 1 / Layer 2-triggered Mobility (LTM) cell switch command, which may be sent by the network node carrying out the method of Figure 10 or another network node. In others, it may be triggered by a Layer 3-based reconfiguration or conditional handover, which again may be sent by the network node carrying out the method of Figure 10 or another.

[0293] As was the case with the corresponding method shown in Figure 9, the "information" referred to above may comprise any of the following: an indication of activation / deactivation status of each of one or more TCI states associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of downlink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of uplink presynchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; one or more indications of the activation / deactivation status of the one or more TCI states associated to each of one or more candidate cells for mobility; one or more indications indicating downlink pre-synchronization status associated to one or more candidate cells for mobility; one or more indications indicating uplink pre-synchronization status associated to one or more candidate cells for mobility; one or more indications indicating activation / deactivation status of one or more TCI states associated to each of one or more neighboring cells; one or more indications indicating downlink pre-synchronization status associated to one or more neighboring cells; one or more indications indicating uplink pre-synchronization status associated to one or more neighboring cells; and an indication of a cell that activated one or more TCI states associated to the cell in which the UE detected an event triggering the logging. Once again, these are non-limiting examples - the discussion above provides additional examples as well as details and variations of these.

[0294] Figure 11 shows an example of a communication system 1100 in accordance with some embodiments. In this example, communication system 1100 includes telecommunication network 1102 that includes access network 1104 (e.g., RAN) and a core network 1106, which includes one or more core network nodes 1108. Access network 1104 includes one or more access network nodes, such as network nodes lllOa-b (one or more of which may be generally referred to as network nodes 1110), or any other similar 3GPP access node or non-3GPP access point. Network nodes 1110 facilitate direct or indirect connection of UEs, such as by connecting UEs 1112a-d (one or more of which may be generally referred to as UEs 1112) to core network 1106 over one or more wireless connections.

[0295] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, communication system 1100 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. Communication system 1100 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0296] UEs 1112 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with network nodes 1110 and other communication devices. Similarly, network nodes 1110 are arranged, capable, configured, and / or operable to communicate directly or indirectly with UEs 1112 and / or with other network nodes or equipment in telecommunication network 1102 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in telecommunication network 1102. In the depicted example, core network 1106 connects network nodes 1110 to one or more hosts, such as host 1116. 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. Core network 1106 includes one or more core network nodes (e.g., 1108) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of core network node 1108. 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).

[0297] Host 1116 may be under the ownership or control of a service provider other than an operator or provider of access network 1104 and / or telecommunication network 1102, and may be operated by the service provider or on behalf of the service provider. Host 1116 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.

[0298] As a whole, communication system 1100 of Figure 11 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0299] In some examples, telecommunication network 1102 is a cellular network that implements 3GPP standardized features. Accordingly, telecommunication network 1102 may support network slicing to provide different logical networks to different devices that are connected to telecommunication network 1102. For example, telecommunication network 1102 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive loT services to yet further UEs.

[0300] In some examples, UEs 1112 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to access network 1104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from access network 1104. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e., being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN- DC).

[0301] In the example, hub 1114 communicates with access network 1104 to facilitate indirect communication between one or more UEs (e.g., UE 1112c and / or 1112d) and network nodes (e.g., network node 1110b). In some examples, hub 1114 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, hub 1114 may be a broadband router enabling access to core network 1106 for the UEs. As another example, hub 1114 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 1110, or by executable code, script, process, or other instructions in hub 1114. As another example, hub 1114 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, hub 1114 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, hub 1114 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which hub 1114 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, hub 1114 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.

[0302] Hub 1114 may have a constant / persistent or intermittent connection to network node 1110b. Hub 1114 may also allow for a different communication scheme and / or schedule between hub 1114 and UEs (e.g., UE 1112c and / or 1112d), and between hub 1114 and core network 1106. In other examples, hub 1114 is connected to core network 1106 and / or one or more UEs via a wired connection. Moreover, hub 1114 may be configured to connect to an M2M service provider over access network 1104 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with network nodes 1110 while still connected via hub 1114 via a wired or wireless connection. In some embodiments, hub 1114 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to network node 1110b. In other embodiments, hub 1114 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 1110b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0303] Figure 12 shows a UE 1200 in accordance with some embodiments. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by 3GPP, including a narrow band internet of things (NB-loT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0304] A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to- vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0305] UE 1200 includes processing circuitry 1202 that is operatively coupled via bus 1204 to input / output interface 1206, power source 1208, memory 1210, communication interface 1212, and possibly other components not explicitly shown. Certain UEs may utilize all or a subset of the components shown in Figure 12. 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. Processing circuitry 1202 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine- readable computer programs in memory 1210. Processing circuitry 1202 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, processing circuitry 1202 may include multiple central processing units (CPUs).

[0306] In the example, input / output interface 1206 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into UE 1200. 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.

[0307] In some embodiments, power source 1208 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. Power source 1208 may further include power circuitry for delivering power from power source 1208 itself, and / or an external power source, to the various parts of UE 1200 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging power source 1208. Power circuitry may perform any formatting, converting, or other modification to the power from power source 1208 to make the power suitable for the respective components of UE 1200 to which power is supplied.

[0308] Memory 1210 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable readonly 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, memory 1210 includes one or more application programs 1214, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1216. Memory 1210 may store, for use by UE 1200, any of a variety of various operating systems or combinations of operating systems.

[0309] Memory 1210 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUlCC), integrated UICC (iUICC) or a removable UICC commonly known as 'SIM card.' Memory 1210 may allow UE 1200 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 memory 1210, which may be or comprise a device-readable storage medium.

[0310] Processing circuitry 1202 may be configured to communicate with an access network or other network using communication interface 1212. Communication interface 1212 may comprise one or more communication subsystems and may include or be communicatively coupled to antenna 1222. Communication interface 1212 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 transmitter 1218 and / or receiver 1220 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, transmitter 1218 and receiver 1220 may be coupled to one or more antennas (e.g., 1222) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0311] In the illustrated embodiment, communication functions of communication interface 1212 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), Q.UIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0312] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1212, 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 16 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., an alert is sent when moisture is detected), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0313] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0314] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or 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 loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to UE 1200 shown in Figure 12.

[0315] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-loT 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.

[0316] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone's speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone's speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0317] Figure 13 shows a network node 1300 in accordance with some embodiments. Examples of network nodes include, but are not limited to, access points (e.g., radio access points) and base stations (e.g., radio base stations, Node Bs, eNBs, and gNBs).

[0318] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0319] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0320] Network node 1300 includes processing circuitry 1302, memory 1304, communication interface 1306, and power source 1308. Network node 1300 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 network node 1300 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, network node 1300 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1304 for different RATs) and some components may be reused (e.g., a same antenna 1310 may be shared by different RATs). Network node 1300 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1300, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1300.

[0321] Processing circuitry 1302 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 1300 components, such as memory 1304, to provide network node 1300 functionality.

[0322] In some embodiments, processing circuitry 1302 includes a system on a chip (SOC). In some embodiments, processing circuitry 1302 includes one or more of radio frequency (RF) transceiver circuitry 1312 and baseband processing circuitry 1314. In some embodiments, RF transceiver circuitry 1312 and baseband processing circuitry 1314 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 1312 and baseband processing circuitry 1314 may be on the same chip or set of chips, boards, or units. Memory 1304 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non- transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by processing circuitry 1302. Memory 1304 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 (collectively denoted computer program product 1304a) capable of being executed by processing circuitry 1302 and utilized by network node 1300. Memory 1304 may be used to store any calculations made by processing circuitry 1302 and / or any data received via communication interface 1306. In some embodiments, processing circuitry 1302 and memory 1304 is integrated.

[0323] Communication interface 1306 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, communication interface 1306 comprises port(s) / terminal(s) 1316 to send and receive data, for example to and from a network over a wired connection. Communication interface 1306 also includes radio front-end circuitry 1318 that may be coupled to, or in certain embodiments a part of, antenna 1310. Radio front-end circuitry 1318 comprises filters 1320 and amplifiers 1322. Radio front-end circuitry 1318 may be connected to antenna 1310 and processing circuitry 1302. The radio front-end circuitry may be configured to condition signals communicated between antenna 1310 and processing circuitry 1302. Radio frontend circuitry 1318 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. Radio front-end circuitry 1318 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1320 and / or amplifiers 1322. The radio signal may then be transmitted via antenna 1310. Similarly, when receiving data, antenna 1310 may collect radio signals which are then converted into digital data by radio front-end circuitry 1318. The digital data may be passed to processing circuitry 1302. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0324] In certain alternative embodiments, network node 1300 does not include separate radio front-end circuitry 1318, instead, processing circuitry 1302 includes radio front-end circuitry and is connected to antenna 1310. Similarly, in some embodiments, all or some of RF transceiver circuitry 1312 is part of communication interface 1306. In still other embodiments, communication interface 1306 includes one or more ports or terminals 1316, radio front-end circuitry 1318, and RF transceiver circuitry 1312, as part of a radio unit (not shown), and communication interface 1306 communicates with the baseband processing circuitry 1314, which is part of a digital unit (not shown).

[0325] Antenna 1310 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. Antenna 1310 may be coupled to radio front-end circuitry 1318 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, antenna 1310 is separate from network node 1300 and connectable to network node 1300 through an interface or port.

[0326] Antenna 1310, communication interface 1306, and / or processing circuitry 1302 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, antenna 1310, communication interface 1306, and / or processing circuitry 1302 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.

[0327] Power source 1308 provides power to the various components of network node 1300 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). Power source 1308 may further comprise, or be coupled to, power management circuitry to supply the components of network node 1300 with power for performing the functionality described herein. For example, network node 1300 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 power source 1308. As a further example, power source 1308 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0328] Embodiments of network node 1300 may include additional components beyond those shown in Figure 13 for providing certain aspects of the network node's functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, network node 1300 may include user interface equipment to allow input of information into network node 1300 and to allow output of information from network node 1300. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for network node 1300.

[0329] Figure 14 is a block diagram illustrating a virtualization environment 1400 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1400 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized.

[0330] Applications 1402 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 1400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0331] Hardware 1404 includes processing circuitry, memory that stores software and / or instructions (collectively denoted computer program product 1404a) 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 1406 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1408a-b (one or more of which may be generally referred to as VMs 1408), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 1406 may present a virtual operating platform that appears like networking hardware to VMs 1408.

[0332] VMs 1408 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1406. Different embodiments of the instance of a virtual appliance 1402 may be implemented on one or more of VMs 1408, and the implementations may differ. 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.

[0333] In the context of NFV, each VM 1408 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of VMs 1408, and that part of hardware 1404 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 1408 on top of hardware 1404 and corresponds to application 1402.

[0334] Hardware 1404 may be implemented in a standalone network node with generic or specific components. Hardware 1404 may implement some functions via virtualization. Alternatively, hardware 1404 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 1410, which, among others, oversees lifecycle management of applications 1402. In some embodiments, hardware 1404 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 control system 1412 which may alternatively be used for communication between hardware nodes and radio units.

[0335] The foregoing merely illustrates the principles of the disclosure. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements, and procedures that, although not explicitly shown or described herein, embody the principles of the disclosure and can be thus within the spirit and scope of the disclosure. Various embodiments can be used together with one another, as well as interchangeably therewith, as should be understood by those having ordinary skill in the art.

[0336] The term unit, as used herein, can have conventional meaning in the field of electronics, electrical devices and / or electronic devices and can include, for example, electrical and / or electronic circuitry, devices, modules, processors, memories, logic solid state and / or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and / or displaying functions, and so on, as such as those that are described herein.

[0337] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and / or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according to one or more embodiments of the present disclosure.

[0338] As described herein, device and / or apparatus can be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of a device or apparatus, instead of being hardware implemented, be implemented as a software module such as a computer program or a computer program product comprising executable software code portions for execution or being run on a processor. Furthermore, functionality of a device or apparatus can be implemented by any combination of hardware and software. A device or apparatus can also be regarded as an assembly of multiple devices and / or apparatuses, whether functionally in cooperation with or independently of each other. Moreover, devices and apparatuses can be implemented in a distributed fashion throughout a system, so long as the functionality of the device or apparatus is preserved. Such and similar principles are considered as known to a skilled person.

[0339] Furthermore, functions described herein as being performed by a wireless device or a network node may be distributed over a plurality of wireless devices and / or network nodes. In other words, it is contemplated that the functions of the network node and wireless device described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices. In addition, certain terms used in the present disclosure, including the specification, drawings and embodiments thereof, can be used synonymously in certain instances, including, but not limited to, e.g., data and information. It should be understood that, while these words and / or other words that can be synonymous to one another, can be used synonymously herein, that there can be instances when such words can be intended to not be used synonymously. Further, to the extent that the prior art knowledge has not been explicitly incorporated by reference herein above, it is explicitly incorporated herein in its entirety. All publications referenced are incorporated herein by reference in their entireties.

[0340] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0341] In addition, certain terms used in the present disclosure, including the specification and drawings, can be used synonymously in certain instances (e.g., "data" and "information"). It should be understood, that although these terms (and / or other terms that can be synonymous to one another) can be used synonymously herein, there can be instances when such words can be intended to not be used synonymously.

[0342] The techniques and apparatus described herein include, but are not limited to, the following enumerated examples:

[0343] Al. A method, in a user equipment (UE) operating in a wireless network, the method comprising: receiving, from the wireless network, a command instructing the UE to perform downlink pre-synchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed; and subsequently logging, in response to a successful change or addition of cell or in response to a failed mobility procedure, information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in the command.

[0344] A2. The method of example embodiment Al, wherein the method further comprises transmitting the logged information to the wireless network. A3. The method of example embodiment A2, wherein the method comprises, prior to said transmitting, sending an indication of the availability of the logged information to the wireless network, wherein said transmitting is in response to receipt of a request for the logged information.

[0345] A4. The method of any one of example embodiments A1-A3, wherein the command is a TCI state activation command or a TCI state deactivation command.

[0346] A5. The method of any one of example embodiments A1-A4, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 1 / Layer 2-triggered Mobility (LTM) cell switch command.

[0347] A6. The method of any of example embodiments A1-A4, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 3-based reconfiguration or conditional handover.

[0348] A7. The method of any one of example embodiments A1-A6, wherein the logged information comprises any one or more of: an indication of activation / deactivation status of each of one or more TCI states associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of downlink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of uplink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; one or more indications of the activation / deactivation status of the one or more TCI states associated to each of one or more candidate cells for mobility; one or more indications indicating downlink pre-synchronization status associated to one or more candidate cells for mobility; one or more indications indicating uplink pre-synchronization status associated to one or more candidate cells for mobility; one or more indications indicating activation / deactivation status of one or more TCI states associated to each of one or more neighboring cells; one or more indications indicating downlink pre-synchronization status associated to one or more neighboring cells; one or more indications indicating uplink pre-synchronization status associated to one or more neighboring cells; and an indication of a cell that activated one or more TCI states associated to the cell in which the UE detected an event triggering the logging.

[0349] A8. The method of any of example embodiments A1-A7, wherein said logging is responsive to execution of a mobility procedure towards a beam of a target cell for which TCI state activation was received while the UE was connected to a source cell for the mobility procedure.

[0350] A9. The method of any of example embodiments A1-A8, wherein at least some of the logged information is timing-related information related to a last TCI state activation command or last TCI state deactivation received by the UE while the UE was connected to a source cell prior to a mobility procedure execution.

[0351] A10. The method of any of example embodiments A1-A9, wherein the method includes including the logged information in a radio link failure report.

[0352] All. The method of example embodiment A10, wherein the radio link failure report is triggered after a successful mobility procedure following reception of the command.

[0353] A12. The method of any of example embodiments A1-A8, wherein the method includes including the logged information in a successful handover report.

[0354] Bl. A method, in a network node operating in a wireless network, the method comprising: receiving, from a user equipment (UE), a report of a successful or unsuccessful mobility event or of a radio link failure, the report comprising information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in a command from the wireless network instructing the UE to perform downlink presynchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed, the information having been logged by the UE in response to a subsequent successful change or addition of cell or failed mobility procedure. B2. The method of any one of example embodiments B1-B3, wherein the method comprises receiving the report in response to a request for the report sent to the UE.

[0355] B3. The method of example embodiment B2, wherein the method comprises receiving, from the UE, an indication that the report is available and sending the request for the report in response to said indication.

[0356] B4. The method of any one of example embodiments B1-B3, wherein the command is a TCI state activation command or a TCI state deactivation command.

[0357] B5. The method of any one of example embodiments B1-B4, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 1 / Layer 2-triggered Mobility (LTM) cell switch command.

[0358] B6. The method of any of example embodiments B1-B4, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 3-based reconfiguration or conditional handover.

[0359] B7. The method of any one of example embodiments B1-B6, wherein the information comprises any one or more of: an indication of activation / deactivation status of each of one or more TCI states associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of downlink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of uplink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; one or more indications of the activation / deactivation status of the one or more TCI states associated to each of one or more candidate cells for mobility; one or more indications indicating downlink pre-synchronization status associated to one or more candidate cells for mobility; one or more indications indicating uplink pre-synchronization status associated to one or more candidate cells for mobility; one or more indications indicating activation / deactivation status of one or more TCI states associated to each of one or more neighboring cells; one or more indications indicating downlink pre-synchronization status associated to one or more neighboring cells; one or more indications indicating uplink pre-synchronization status associated to one or more neighboring cells; and an indication of a cell that activated one or more TCI states associated to the cell in which the UE detected an event triggering the logging.

[0360] B8. The method of any of example embodiments B1-B7, wherein at least some of the logged information is timing-related information related to a last TCI state activation command or last TCI state deactivation received by the UE while the UE was connected to a source cell prior to a mobility procedure execution.

[0361] B9. The method of any of example embodiments B1-B8, wherein the information is received in a radio link failure report.

[0362] BIO. The method of any of example embodiments B1-B8, wherein the information is received in a successful handover report.

[0363] Cl. A user equipment, UE, comprising: communication interface circuitry configured to communicate with a RAN node via at least one serving cell; and processing circuitry operably coupled to the communication interface circuitry, wherein the processing circuitry and communication interface circuitry are configured to: receive, from the wireless network, a command instructing the UE to perform downlink presynchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed; and subsequently log, in response to a successful change or addition of cell or in response to a failed mobility procedure, information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in the command.

[0364] C2. The UE of example embodiment Cl, wherein the processing circuitry and communication interface circuitry are further configured to transmit the logged information to the wireless network. C3. The UE of example embodiment C2, wherein the processing circuitry and communication interface circuitry are configured to, prior to said transmitting, send an indication of the availability of the logged information to the wireless network, wherein said transmitting is in response to receipt of a request for the logged information.

[0365] C4. The UE of any one of example embodiments C1-C3, wherein the command is a TCI state activation command or a TCI state deactivation command.

[0366] C5. The UE of any one of example embodiments C1-C4, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 1 / Layer 2-triggered Mobility (LTM) cell switch command.

[0367] C6. The UE of any of example embodiments C1-C4, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 3-based reconfiguration or conditional handover.

[0368] C7. The UE of any one of example embodiments C1-C6, wherein the logged information comprises any one or more of: an indication of activation / deactivation status of each of one or more TCI states associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of downlink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of uplink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; one or more indications of the activation / deactivation status of the one or more TCI states associated to each of one or more candidate cells for mobility; one or more indications indicating downlink pre-synchronization status associated to one or more candidate cells for mobility; one or more indications indicating uplink pre-synchronization status associated to one or more candidate cells for mobility; one or more indications indicating activation / deactivation status of one or more TCI states associated to each of one or more neighboring cells; one or more indications indicating downlink pre-synchronization status associated to one or more neighboring cells; one or more indications indicating uplink pre-synchronization status associated to one or more neighboring cells; and an indication of a cell that activated one or more TCI states associated to the cell in which the UE detected an event triggering the logging.

[0369] C8. The UE of any of example embodiments C1-C7, wherein the processing circuitry and communication interface circuitry are configured to perform said logging responsive to execution of a mobility procedure towards a beam of a target cell for which TCI state activation was received while the UE was connected to a source cell for the mobility procedure.

[0370] C9. The UE of any of example embodiments C1-C8, wherein at least some of the logged information is timing-related information related to a last TCI state activation command or last TCI state deactivation received by the UE while the UE was connected to a source cell prior to a mobility procedure execution.

[0371] CIO. The UE of any of example embodiments C1-C9, wherein the processing circuitry and communication interface circuitry are configured to include the logged information in a radio link failure report.

[0372] Cll. The UE of example embodiment CIO, wherein the radio link failure report is triggered after a successful mobility procedure following reception of the command.

[0373] C12. The UE of any of example embodiments C1-C8, wherein the processing circuitry and communication interface circuitry are configured to include the logged information in a successful handover report.

[0374] C13. A user equipment, UE, being adapted to: receive, from the wireless network, a command instructing the UE to perform downlink presynchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed; and subsequently log, in response to a successful change or addition of cell or in response to a failed mobility procedure, information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in the command. C14. The UE of example embodiment C13, being further adapted to perform operations corresponding to any of the methods of example embodiments A2-A12.

[0375] C15. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a user equipment, UE, configure the UE to perform operations corresponding to any of the methods of example embodiments A1-A12.

[0376] C16. A computer program product comprising computer-executable instructions that, when executed by processing circuitry of a user equipment, UE, configure the UE to perform operations corresponding to any of the methods of example embodiments A1-A12.

[0377] DI. A network node, RAN, the network node comprising: communication interface circuitry configured to communicate with one or more user equipments, UEs, via at least one serving cell; and processing circuitry operably coupled to the communication interface circuitry, wherein the processing circuitry and communication interface circuitry are configured to: receive, from a user equipment (UE), a report of a successful or unsuccessful mobility event or of a radio link failure, the report comprising information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in a command from the wireless network instructing the UE to perform downlink pre-synchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed, the information having been logged by the UE in response to a subsequent successful change or addition of cell or failed mobility procedure.

[0378] D2. The network node of any one of example embodiments D1-D3, wherein the processing circuitry and communication interface circuitry are configured to receive the report in response to a request for the report sent to the UE.

[0379] D3. The network node of example embodiment D2, wherein the processing circuitry and communication interface circuitry are configured to receive, from the UE, an indication that the report is available, and send the request for the report in response to said indication. D4. The network node of any one of example embodiments D1-D3, wherein the command is a TCI state activation command or a TCI state deactivation command.

[0380] D5. The network node of any one of example embodiments D1-D4, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 1 / Layer 2-triggered Mobility (LTM) cell switch command.

[0381] D6. The network node of any of example embodiments D1-D4, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 3-based reconfiguration or conditional handover.

[0382] D7. The network node of any one of example embodiments D1-D6, wherein the information comprises any one or more of: an indication of activation / deactivation status of each of one or more TCI states associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of downlink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; an indication of uplink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell; one or more indications of the activation / deactivation status of the one or more TCI states associated to each of one or more candidate cells for mobility; one or more indications indicating downlink pre-synchronization status associated to one or more candidate cells for mobility; one or more indications indicating uplink pre-synchronization status associated to one or more candidate cells for mobility; one or more indications indicating activation / deactivation status of one or more TCI states associated to each of one or more neighboring cells; one or more indications indicating downlink pre-synchronization status associated to one or more neighboring cells; one or more indications indicating uplink pre-synchronization status associated to one or more neighboring cells; and an indication of a cell that activated one or more TCI states associated to the cell in which the UE detected an event triggering the logging. D8. The network node of any of example embodiments D1-D7, wherein at least some of the logged information is timing-related information related to a last TCI state activation command or last TCI state deactivation received by the UE while the UE was connected to a source cell prior to a mobility procedure execution.

[0383] D9. The network node of any of example embodiments D1-D8, wherein the information is received in a radio link failure report.

[0384] DIO. The network node of any of example embodiments D1-D8, wherein the information is received in a successful handover report.

[0385] Dll. A network node, the network node being adapted to: receive, from a user equipment (UE), a report of a successful or unsuccessful mobility event or of a radio link failure, the report comprising information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in a command from the wireless network instructing the UE to perform downlink presynchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed, the information having been logged by the UE in response to a subsequent successful change or addition of cell or failed mobility procedure.

[0386] D12. The network node of example embodiment Dll, wherein the network node is adapted to carry out a method according to any one of example embodiments B2-10.

[0387] D13. A computer program product comprising computer-executable instructions that, when executed by processing circuitry of a network node, configure the network node to perform operations corresponding to any of the methods of example embodiments B1-B10.

[0388] Some Abbreviations:

[0389] BWP Bandwidth Part

[0390] CE Control Element

[0391] CBRA Contention Based Random Access

[0392] CFRA Contention Free Random Access CHO Conditional Handover

[0393] CP Control Plane

[0394] C-RNTI Cell- Radio Network Temporary Identifier.

[0395] CSI Channel State Information

[0396] CSI-RS Channel State Information - Reference Signal

[0397] CU Central unit

[0398] CU-gNB gNB-CU

[0399] DCI Downlink Control Information

[0400] DL Downlink

[0401] DRB Data Radio Bearer

[0402] DU Distributed unit eNB Base station supporting the LTE air interface gNB Base station supporting the NR air interface gNB-CU gNB Central Unit gNB-DU gNB Distributed Unit

[0403] HARQ. Hybrid Automatic Repeat Request

[0404] HOF Handover Failure

[0405] IE Information Element

[0406] LI Layer-1

[0407] L2 Layer-2

[0408] L3 Layer-3

[0409] LTE Long Term Evolution

[0410] LTM Layer 1 / Layer 2 (Ll / L2)-Triggered Mobility, or Lower-Layer Triggered Mobility

[0411] MAC Medium Access Control

[0412] MDT Minimization of Drive Test

[0413] MHI Mobility History Report

[0414] MCG Master Cell Group

[0415] MN Master Node

[0416] NR New Radio

[0417] PCell Primary Cell

[0418] PCI Physical cell identifier

[0419] PDCCH Physical Downlink Control Channel

[0420] PSCell Primary Secondary Cell

[0421] PRACH Physical Random Access Channel QCI Quality of Service Class Indicator

[0422] RA Random Access

[0423] RACH Random Access Channel

[0424] RACH based Random Access Channel based

[0425] RACH-less Random Access Channel Less (i.e., without RA procedure)

[0426] RAN Radio Access Network

[0427] RAT Radio Access Technology

[0428] RLF Radio Link Failure

[0429] RRC Radio Resource Control

[0430] RS Reference Signal

[0431] RSRP Received Signal Received Power

[0432] RSRQ Received Signal Received Quality

[0433] RSSI Received Signal Strength Indicator

[0434] SCell Secondary Cell

[0435] S / U supplementary uplink / uplink

[0436] SCG Secondary Cell Group

[0437] S-DU Source Distributed Unit

[0438] S-gNB-DU Source-gNB-Distributed Unit

[0439] SHR Successful Handover Report

[0440] SINR Signal to Interference Noise ratio

[0441] SN Secondary Node

[0442] SpCell Special Cell

[0443] SSB Synchronization Signal / PBCH block (SSB)

[0444] SS / PBCH Synchronization Signal / Physical Broadcast Channel

[0445] SS-RSRP Synchronization Signal-Received Signal Received Power

[0446] SS-RSRQ Synchronization Signal-Received Signal Received Quality

[0447] SS-SINR Synchronization Signal-Signal To Interference Noise Ratio

[0448] TA Time Advance

[0449] TCI Transmission Configuration Indicator

[0450] UE User Equipment

[0451] UL Uplink

[0452] WLAN AP Wireless Local-Area Network Access Point

Claims

CLAIMS1. A method, in a user equipment, UE, operating in a wireless network, the method comprising: receiving (910), from the wireless network, a command instructing the UE to perform downlink pre-synchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed; and subsequently logging (920), in response to a successful change or addition of cell or in response to a failed mobility procedure, information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in the command.

2. The method of claim 1, wherein the method further comprises transmitting (990) the logged information to the wireless network.

3. The method of claim 1 or 2, wherein the command is a Transmission Configuration Indicator, TCI, state activation command or a TCI state deactivation command.

4. The method of any one of claims 1-3, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 1 / Layer 2-triggered Mobility, LTM, cell switch command.

5. The method of any one of claims 1-4, wherein the logged information comprises an indication of downlink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell.

6. The method of any one of claims 1-4, wherein the logged information comprises one or more indications indicating downlink pre-synchronization status associated to one or more candidate cells for mobility.

7. The method of any of claims 1-6, wherein said logging (920) is responsive to execution of a mobility procedure towards a beam of a target cell for which TCI state activation was received while the UE was connected to a source cell for the mobility procedure.

8. The method of any of claims 1-7, wherein at least some of the logged information is timing-related information related to a last TCI state activation command or last TCI state deactivation received by the UE while the UE was connected to a source cell prior to a mobility procedure execution.

9. A method, in a network node operating in a wireless network, the method comprising:Receiving (1030), from a user equipment, UE, a report of a successful or unsuccessful mobility event or of a radio link failure, the report comprising information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in a command from the wireless network instructing the UE to perform downlink presynchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed, the information having been logged by the UE in response to a subsequent successful change or addition of cell or failed mobility procedure.

10. The method of claim 9, wherein the method comprises receiving (1030) the report in response to a request for the report sent to the UE.

11. The method of claim 9 or 10, wherein the command is a Transmission Configuration Indicator, TCI, state activation command or a TCI state deactivation command.

12. The method of any one of claims 9-11, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 1 / Layer 2-triggered Mobility, LTM, cell switch command.

13. The method of any one of claims 9-12, wherein the information comprises an indication of downlink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell.

14. The method of any one of claims 9-12, wherein the information comprises one or more indications indicating downlink pre-synchronization status associated to one or more candidate cells for mobility.

15. The method of any of claims 9-14, wherein at least some of the logged information is timing- related information related to a last TCI state activation command or last TCI state deactivation received by the UE while the UE was connected to a source cell prior to a mobility procedure execution.

16. A user equipment, UE, comprising: communication interface circuitry configured to communicate with a wireless network via at least one serving cell; and processing circuitry operably coupled to the communication interface circuitry, wherein the processing circuitry and communication interface circuitry are configured to: receive, from the wireless network, a command instructing the UE to perform downlink pre-synchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed; and subsequently log, in response to a successful change or addition of cell or in response to a failed mobility procedure, information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in the command.

17. The UE of claim 16, wherein the processing circuitry and communication interface circuitry are further configured to transmit the logged information to the wireless network.

18. The UE of claim 16 or 17, wherein the command is a Transmission Configuration Indicator, TCI, state activation command or a TCI state deactivation command.

19. The UE of any one of claims 16-18, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 1 / Layer 2-triggered Mobility (LTM) cell switch command.

20. The UE of any one of claims 16-19, wherein the logged information comprises an indication of downlink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell.

21. The UE of any one of claims 16-19, wherein the logged information comprises one or more indications indicating downlink pre-synchronization status associated to one or more candidate cells for mobility.

22. The UE of any of claims 16-21, wherein the processing circuitry and communication interface circuitry are configured to perform said logging responsive to execution of a mobility proceduretowards a beam of a target cell for which TCI state activation was received while the UE was connected to a source cell for the mobility procedure.

23. The UE of any of claims 16-22, wherein at least some of the logged information is timing-related information related to a last TCI state activation command or last TCI state deactivation received by the UE while the UE was connected to a source cell prior to a mobility procedure execution.

24. A network node, comprising: communication interface circuitry configured to communicate with one or more user equipments, UEs, via at least one serving cell; and processing circuitry operably coupled to the communication interface circuitry, wherein the processing circuitry and communication interface circuitry are configured to: receive, from a UE, a report of a successful or unsuccessful mobility event or of a radio link failure, the report comprising information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in a command from the wireless network instructing the UE to perform downlink pre-synchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed, the information having been logged by the UE in response to a subsequent successful change or addition of cell or failed mobility procedure.

25. The network node of claim 24, wherein the processing circuitry and communication interface circuitry are configured to receive the report in response to a request for the report sent to the UE.

26. The network node of claim24 or 25, wherein the command is a Transmission Configuration Indicator, TCI, state activation command or a TCI state deactivation command.

27. The network node of any one of claims 24-26, wherein the successful change or addition of cell or failed mobility procedure is triggered by a Layer 1 / Layer 2-triggered Mobility, ,LTM, cell switch command.

28. The network node of any one of claims 24-27, wherein the information comprises an indication of downlink pre-synchronization status associated to a target cell of the mobility procedure or successful change or addition of cell.

29. The network node of any one of claims 24-27, wherein the information comprises one or more indications indicating downlink pre-synchronization status associated to one or more candidate cells for mobility.

30. The network node of any of claims 24-29, wherein at least some of the logged information is timing-related information related to a last TCI state activation command or last TCI state deactivation received by the UE while the UE was connected to a source cell prior to a mobility procedure execution.

31. A user equipment, UE, being adapted to: receive, from a wireless network, a command instructing the UE to perform downlink presynchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed; and subsequently log, in response to a successful change or addition of cell or in response to a failed mobility procedure, information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in the command.

32. The UE of claim 31, being further adapted to perform operations corresponding to any of the methods of claims 2-8.

33. A network node, the network node being adapted to: receive, from a UE, a report of a successful or unsuccessful mobility event or of a radio link failure, the report comprising information identifying and / or otherwise regarding one or more candidate cells and / or beams indicated in a command from the wireless network instructing the UE to perform downlink pre-synchronization for a candidate target cell for mobility or informing the UE that downlink synchronization for the candidate target cell for mobility is no longer needed, the information having been logged by the UE in response to a subsequent successful change or addition of cell or failed mobility procedure.

34. The network node of claim 33, wherein the network node is further adapted to carry out a method according to any of the methods of claims 10-15.

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