WO2024033139A1

WO2024033139A1 - Joint radio link failure (rlf) detection for l1/l2 inter-cell mobility

Info

Publication number: WO2024033139A1
Application number: PCT/EP2023/071202
Authority: WO
Inventors: Icaro Leonardo DA SILVA; Antonino ORSINO
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2022-08-09
Filing date: 2023-07-31
Publication date: 2024-02-15

Abstract

The present disclosure is related to a UE and a method for joint radio link failure detection for L1/L2 inter-cell mobility. A method at a UE for RLM is provided. The UE is configured with one or more candidate cells for L1/L2 inter-cell mobility. The method comprises: performing an RLM process based on at least one of a first configuration associated with a serving cell and at least one second configuration associated with at least one of the candidate cells; and continuing the RLM process with or without an update of one or more parameters that are configured for the RLM process in response to receiving a signaling indicating L1/L2 inter-cell mobility execution to a target cell.

Description

JOINT RADIO LINK FAILURE (RLF) DETECTION FOR L1/L2 INTER-CELL MOBILITY

CROSS-REFERENCE TO RELATED APPLICATION (S)

This application claims priority to the U.S. Provisional Patent Application No. 63/370928, entitled " JOINT RLF DETECTION FOR L1/L2 INTER-CELL MOBILITY', filed on August 9, 2022, which is incorporated herein by reference in its entirety.

Technical Field

The present disclosure is related to the field of telecommunication, and in particular, to a User Equipment (UE) and a method for joint radio link failure (RLF) detection for L1/L2 inter-cell mobility.

Background

With the development of the electronic and telecommunication technologies, mobile devices, such as mobile phones, smart phones, laptops, tablets, vehicle mounted devices, become an important part of our daily lives. To support a numerous number of mobile devices, a highly efficient radio access network (RAN), such as a 3^rd Generation Partnership Project (3GPP) 5^th Generation (5G) New Radio (NR) RAN, will be required.

However, the performance of radio networks may be affected by many circumstance factors including (but not limited to) weather-related phenomena (such as clouds, rain, snow, resulting in a less efficient RAN), human activities (such as buildings, social gathering), etc., typically resulting radio link failures for the mobile devices. To reduce the adverse effects of RLFs on the user experience, mobile operators require an accurate and timely detection of such RLFs.

Summary

RLF detection has been defined to allow the UE to detect a failure and perform autonomous mobility (cell selection followed by a Radio Resource Control (RRC) Reestablishment procedure), e.g., when something does not work properly in the transmission of an RRC Measurement report from the UE to the network or in the reception of the response to that report: an RRC Reconfiguration including the Information Element (IE) Reconfiguration with Sync (handover command). This may occur, for example, when the measurement triggers are not optimally tuned.

In L1/L2 inter-cell mobility, the UE is configured with one or more L1/L2 inter-cell mobility candidate cells (e.g. each associated to a physical cell identifier (PCI), which are the cells the UE may be indicated by the network to move to upon reception of a lower layer signaling, such as a Medium Access Control (MAC) Control Element (CE) or Downlink Control Information (DCI), indicating one of the configured L1/L2 inter-cell mobility candidate cells. However, most likely the UE will be configured with a finite number of L1/L2 inter-cell mobility candidate cells, i.e., there will always be some limit or border wherein the UE reaches a cell which has not been configured as a L1/L2 intercell mobility candidate. In addition, because inter-cell L1/L2 inter-cell mobility is only meant to be supported for Intra Central Unit (intra-CU) scenarios, all candidate cells needs to be controlled by the same or different Distributed Units (DUs) of the same CU. So even if the UE could add candidates, it is not possible if the cell the UE is entering the coverage of is associated to another CU.

In this case, RRC based mobility to the cell, which is not any of the candidate cells, is needed. Thus, as discussed above, the fact that RRC-based mobility needs to be supported, at least in these cases the UE leaves the coverage of all configured L1/L2 inter-cell mobility candidates, an RLF mechanism is needed to detect a radio failure for a UE configured with one or more L1/L2 inter-cell mobility candidate(s) is needed, as the RRC measurement reporting framework may not always work.

The existing solution for RLF detection in 5G NR due to radio related problems rely on a Radio Link Monitoring (RLM) process based on the monitoring of the Special Cell (SpCell), such as the PCell in the Master Cell Group (MCG), or the PSCell in the Secondary Cell Group (SCG). However, in L1/L2 inter-cell mobility the UE is not only configured with a SpCell, but in addition, with one or more L1/L2 inter-cell mobility candidates which the UE can move to with L1/L2 inter-cell mobility execution. Hence, the existing framework for RLF detection and RLM may not be suitable, as the UE may actually leave the coverage of the SpCell it connects in the transitions to RRC_CONNECTED, but still be in the coverage of one of the L1/L2 inter-cell mobility candidate cells i.e. in the existing solution the UE would declare RLF even though it is still in the coverage in which it is capable of moving using inter-cell beam management operations. These undesirable (and unnecessary) RLFs and RRC Re-establishment procedures, which degrades the Key Performance Indicators at the network side, increases the signaling, reduces the control at the network side for L1/L2 inter-cell mobility.

Therefore, to address or at least partially alleviate one or more of the above issues, some embodiments of the present disclosure are provided.

According to a first aspect of the present disclosure, a method at a UE for RLM is provided. In some embodiments, the UE is configured with one or more candidate cells for L1/L2 inter-cell mobility. The method comprises: performing an RLM process based on at least one of a first configuration associated with a serving cell and at least one second configuration associated with at least one of the candidate cells; and continuing the RLM process with or without an update of one or more parameters that are configured for the RLM process in response to receiving a signaling indicating L1/L2 inter-cell mobility execution to a target cell.

In some embodiments, the continuing the RLM process with an update of one or more parameters that are configured for the RLM process comprises: updating the one or more parameters based on at least a configuration associated with the target cell in response to the RLM process being performed based not on the second configuration; and continuing the RLM process with the updated parameters. In some embodiments, the performing the RLM process based on at least one of the first configuration and the second configuration comprises: performing the RLM process by monitoring a first set of RLM Reference Signals (RLM-RSs) of the serving cell, wherein the updating the one or more parameters based on at least the configuration associated with the target cell comprises: updating the first set of RLM-RSs of the serving cell with a second set of RLM-RSs indicated by the configuration associated with the target cell, wherein the continuing the RLM process with the updated parameters comprises: continuing the RLM process by monitoring the second set of RLM-RSs.

In some embodiments, the first set of RLM-RSs comprise at least one of: one or more reference signals associated with one or more beams that are being used for transmission of one or more control and/or data channels in the serving cell; one or more Synchronous Signal (SS) and Physical Broadcast Channel (PBCH) blocks (SSBs) configured as Quasi Co-Location (QCL) source of one or more currently activated Transmission Configuration Indicator (TCI) states of the serving cell; one or more Channel State Information Reference Signals (CSI-RSs) configured as QCL source of one or more currently activated TCI states of the serving cell; one or more reference signals associated with one or more beams indicated by the first configuration; one or more SSBs indicated by the first configuration; and one or more CSI-RSs indicated by the first configuration.

In some embodiments, the second set of RLM-RSs comprise at least one of: one or more reference signals associated with one or more beams that are being activated for transmission of one or more control and/or data channels in the target cell; one or more SSBs configured as QCL source of one or more TCI states of the target cell that are being activated; one or more CSI-RSs configured as QCL source of one or more TCI states of the target cell that are being activated; one or more reference signals associated with one or more beams indicated by the configuration associated with the target cell; one or more SSBs indicated by the configuration associated with the target cell; and one or more CSI-RSs indicated by the configuration associated with the target cell.

In some embodiments, the method further comprises: generating an Out Of Sync (OOS) indication in response to determining that measurements on all RLM-RSs in the first set are worse than a configured threshold. In some embodiments, the continuing the RLM process without an update of one or more parameters that are configured for the RLM process comprises: continuing the RLM process by continuing to use the one or more parameters in response to the RLM process being performed based on the first configuration and the second configuration. In some embodiments, the performing the RLM process based on at least one of the first configuration and the second configuration comprises: performing the RLM process by monitoring a single set of RLM- RSs that comprise at least one RLM-RS of the serving cell and at least one RLM-RS of a candidate cell the UE is configured with, wherein the continuing the RLM process by continuing to use the one or more parameters comprises: continuing the RLM process by continuing to monitor the single set of RLM-RSs.

In some embodiments, the single set of RLM-RSs comprise at least one of: one or more RLM-RSs configured for a current active Bandwidth Part (BWP) of the serving cell; one or more reference signals associated with one or more beams configured as QCL source of an activated TCI state of the serving cell; one or more SSBs configured as QCL source of an activated TCI state of the serving cell; one or more CSI-RSs configured as QCL source of an activated TCI state of the serving cell; one or more RLM-RSs configured for a BWP of the configuration associated with the target cell; one or more reference signals configured as QCL source of one or more TCI states of the configuration associated with the target cell; one or more reference signals associated with at least one beam of all candidate cells; and one or more reference signals associated with at least one beam of one or more candidate cells that are explicitly indicated in a configuration. In some embodiments, the method further comprises: receiving, from the target cell, a configuration indicating one or more SSBs and/or CSI- RS resources to be monitored; and reconfiguring the single set of RLM-RSs based on at least the received configuration.

In some embodiments, the method further comprises at least one: activating one or more RLM-RSs in the single set; and deactivating one or more RLM-RSs in the single set. In some embodiments, the activating one or more RLM-RSs in the single set comprises: activating one or more RLM-RSs in the single set that are associated with the target cell in response to the execution of the L1/L2 inter-cell mobility to the target cell. In some embodiments, the deactivating one or more RLM-RSs in the single set comprises: deactivating one or more RLM-RSs in the single set that are associated with the serving cell before the execution of the L1/L2 inter-cell mobility to the target cell. In some embodiments, the method further comprises at least one of: determining the at least one RLM-RS in the single set that is associated with the candidate cell as at least one RLM-RS of the serving cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell; and determining the at least one RLM-RS in the single set that is associated with the serving cell as at least one RLM-RS of the candidate cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

In some embodiments, the method further comprises: determining the at least one RLM-RS in the single set that is associated with the candidate cell as at least one RLM-RS of the serving cell and also at least one RLM-RS of a candidate cell that is different from the serving cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method further comprises: generating an OOS indication in response to determining that measurements on all RLM-RSs in the single set are worse than a configured threshold.

In some embodiments, the continuing to monitor the single set of RLM-RSs is performed only in response to determining that the single set of RLM-RSs comprise at least one RLM-RS of the target cell. In some embodiments, the method further comprises: stopping an RLF timer associated with the RLM process in response to: determining that the RLF timer is running; and receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method further comprises: starting another RLF timer with a value indicated in the configuration associated with the target cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

In some embodiments, the method further comprises: continuing to use an RLF timer associated with the RLM process in response to: determining that the RLF timer is running; and receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method further comprises: stopping the RLF timer in response to: determining that the RLF timer is running; and receiving at least a configured number of consecutive In-Sync (IS) indications from a lower layer of the UE for the target cell. In some embodiments, the method further comprises: resetting an RLF counter associated with the RLF timer while continuing to use the RLF timer in response to: determining that the RLF timer is running; and receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

In some embodiments, the method further comprises: stopping the RLF timer in response to: determining that the RLF timer is running; and receiving at least a configured number of consecutive IS indications from a lower layer of the UE for the serving cell and the target cell. In some embodiments, the method further comprises: continuing to use the RLF timer without resetting an RLF counter associated with the RLF timer in response to: determining that the RLF timer is running; and receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method further comprises: resetting an RLF counter associated with the RLM process in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the resetting the RLF counter comprises: resetting the value of the RLF counter to a corresponding value indicated by the configuration associated with the target cell.

In some embodiments, the method further comprises: continuing to use an RLF counter associated with the RLM process in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method further comprises: stopping an RLF timer associated with the RLF counter, only in response to: determining that the RLF timer is running; and receiving at least a configured number of consecutive IS indications from a lower layer of the UE for the target cell. In some embodiments, the RLF counter is the N310 counter or the N311 counter, wherein the RLF timer is the T310 timer.

In some embodiments, the method further comprises at least one of: stopping or suspending the RLM process in the serving cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell; starting a timer in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell; and transmitting, to a network node associated with the target cell, a first message in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method further comprises at least one of: stopping the timer in response to receiving a second message responsive to the first message while the timer is running; determining that an L1/L2 inter-cell mobility procedure associated with the signaling is successful in response to receiving a second message responsive to the first message while the timer is running; restarting or resuming the RLM process based on at least the configuration associated with the target cell, only in response to receiving a second message responsive to the first message while the timer is running; and determining that an L1/L2 inter-cell mobility procedure associated with the signaling is failed in response to receiving no second message responsive to the first message until the timer is expired.

In some embodiments, the method further comprises at least one of: initiating a RRC Re-establishment procedure in response to detecting an RLF associated with an MCG; and initiating an SCG Failure Report procedure towards a network node operating as a Master Node (MN) for the UE in response to detecting an RLF associated with an SCG. In some embodiments, the configuration associated with the target cell is at least one of: a configuration received in the signaling indicating L1/L2 inter-cell mobility execution to the target cell; and the second configuration.

In some embodiments, the one or more parameters comprise at least one of: one or more reference signals to be measured; one or more RLF counters; and one or more RLF timers. In some embodiments, the signaling is an L1/L2 signaling. In some embodiments, the signaling comprises at least one of: DCI; and MAC CE.

According to a second aspect of the present disclosure, a UE configured with one or more candidate cells for L1/L2 inter-cell mobility is provided. The UE comprises: a processor; a memory storing instructions which, when executed by the processor, cause the UE to: perform an RLM process based on at least one of a first configuration associated with a serving cell and at least one second configuration associated with at least one of the candidate cells; and continue the RLM process with or without an update of one or more parameters that are configured for the RLM process in response to receiving a signaling indicating L1/L2 inter-cell mobility execution to a target cell. In some embodiments, the instructions, when executed by the processor, further cause the UE to perform any of the methods of the first aspect.

According to a third aspect of the present disclosure, a UE configured with one or more candidate cells for L1/L2 inter-cell mobility is provided. The UE comprises: a performing module configured to perform an RLM process based on at least one of a first configuration associated with a serving cell and at least one second configuration associated with at least one of the candidate cells; and a continuing module configured to continue the RLM process with or without an update of one or more parameters that are configured for the RLM process in response to receiving a signaling indicating L1/L2 inter-cell mobility execution to a target cell. In some embodiments, the UE may comprise one or more further modules, each of which may perform any of the steps of any of the methods of the first aspect.

According to a fourth aspect of the present disclosure, a computer program comprising instructions is provided. The instructions, when executed by at least one processor, cause the at least one processor to carry out any of the methods of the first aspect.

According to a fifth aspect of the present disclosure, a carrier containing the computer program of the fourth aspect is provided. In some embodiments, the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

According to a sixth aspect of the present disclosure, a telecommunication system is provided. The telecommunication system comprises: at least one UE configured with one or more candidate cells for L1/L2 inter-cell mobility, the UE comprising: a processor; a memory storing instructions which, when executed by the processor, cause the UE to: perform an RLM process based on at least one of a first configuration associated with a serving cell and at least one second configuration associated with at least one of the candidate cells; and continue the RLM process with or without an update of one or more parameters that are configured for the RLM process in response to receiving a signaling indicating L1/L2 inter-cell mobility execution to a target cell. In some embodiments, the instructions stored in the memory of the corresponding UE, when executed by the processor of the corresponding UE, further cause the corresponding UE to perform any of the methods of the first aspect.

With some embodiments of the present disclosure, it is possible to detect an RLF when the UE is configured with one or more L1/L2 inter-cell mobility candidate cells the UE can move to with L1/L2 inter-cell mobility execution. Hence, when the UE leaves the coverage of the SpCell it connects in the transitions to RRC_CONNECTED, but is still in the coverage of one of the L1/L2 inter-cell mobility candidate cells, i.e. the UE would not declare RLF if still in the coverage in which it is capable of moving using inter-cell beam management operations.

Brief Description of the Drawings

Fig. 1 is a diagram illustrating an exemplary procedure for declaring an RLF.

Fig. 2 is a diagram illustrating an exemplary telecommunication network in which a UE leaves a coverage area of L1/L2 inter-cell mobility candidate cells and in which joint RLF detection for L1/L2 inter-cell mobility is applicable according to an embodiment of the present disclosure.

Fig. 3 is a flow chart illustrating an exemplary method at a UE for RLM according to an embodiment of the present disclosure.

Fig. 4 schematically shows an embodiment of an arrangement which may be used in a UE according to an embodiment of the present disclosure.

Fig. 5 is a block diagram of an exemplary UE according to an embodiment of the present disclosure.

Fig. 6 shows an example of a communication system in accordance with some embodiments of the present disclosure.

Fig. 7 shows an exemplary User Equipment (UE) in accordance with some embodiments of the present disclosure.

Fig. 8 shows an exemplary network node in accordance with some embodiments of the present disclosure.

Fig. 9 is a block diagram of an exemplary host, which may be an embodiment of the host of Fig. 6, in accordance with various aspects described herein. Fig. 10 is a block diagram illustrating an exemplary virtualization environment in which functions implemented by some embodiments may be virtualized.

Fig. 11 shows a communication diagram of an exemplary host communicating via an exemplary network node with an exemplary UE over a partially wireless connection in accordance with some embodiments of the present disclosure.

Detailed Description

Hereinafter, the present disclosure is described with reference to embodiments shown in the attached drawings. However, it is to be understood that those descriptions are just provided for illustrative purpose, rather than limiting the present disclosure. Further, in the following, descriptions of known structures and techniques are omitted so as not to unnecessarily obscure the concept of the present disclosure.

Those skilled in the art will appreciate that the term "exemplary" is used herein to mean "illustrative," or "serving as an example," and is not intended to imply that a particular embodiment is preferred over another or that a particular feature is essential. Likewise, the terms "first", "second", "third", "fourth," and similar terms, are used simply to distinguish one particular instance of an item or feature from another, and do not indicate a particular order or arrangement, unless the context clearly indicates otherwise. Further, the term "step," as used herein, is meant to be synonymous with "operation" or "action." Any description herein of a sequence of steps does not imply that these operations must be carried out in a particular order, or even that these operations are carried out in any order at all, unless the context or the details of the described operation clearly indicates otherwise.

Conditional language used herein, such as "can," "might," "may," "e.g.," and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment. Also, the term "or" is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Further, the term "each," as used herein, in addition to having its ordinary meaning, can mean any subset of a set of elements to which the term "each" is applied.

The term "based on" is to be read as "based at least in part on." The term "one embodiment" and "an embodiment" are to be read as "at least one embodiment." The term "another embodiment" is to be read as "at least one other embodiment." Other definitions, explicit and implicit, may be included below. In addition, language such as the phrase "at least one of X, Y and Z," unless specifically stated otherwise, is to be understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z, or a combination thereof.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limitation of example embodiments. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "has", "having", "includes" and/or "including", when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/ or combinations thereof. It will be also understood that the terms "connect(s)," "connecting", "connected", etc. when used herein, just mean that there is an electrical or communicative connection between two elements and they can be connected either directly or indirectly, unless explicitly stated to the contrary.

Of course, the present disclosure may be carried out in other specific ways than those set forth herein without departing from the scope and essential characteristics of the disclosure. One or more of the specific processes discussed below may be carried out in any electronic device comprising one or more appropriately configured processing circuits, which may in some embodiments be embodied in one or more applicationspecific integrated circuits (ASICs). In some embodiments, these processing circuits may comprise one or more microprocessors, microcontrollers, and/or digital signal processors programmed with appropriate software and/or firmware to carry out one or more of the operations described above, or variants thereof. In some embodiments, these processing circuits may comprise customized hardware to carry out one or more of the functions described above. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Although multiple embodiments of the present disclosure will be illustrated in the accompanying Drawings and described in the following Detailed Description, it should be understood that the disclosure is not limited to the disclosed embodiments, but instead is also capable of numerous rearrangements, modifications, and substitutions without departing from the present disclosure that as will be set forth and defined within the claims.

Further, please note that although the following description of some embodiments of the present disclosure is given in the context of 5G NR, the present disclosure is not limited thereto. In fact, as long as joint RLF detection for L1/L2 intercell mobility is involved, the inventive concept of the present disclosure may be applicable to any appropriate communication architecture, for example, to Global System for Mobile Communications (GSM) I General Packet Radio Service (GPRS), Enhanced Data Rates for GSM Evolution (EDGE), Code Division Multiple Access (CDMA), Wideband CDMA (WCDMA), Time Division - Synchronous CDMA (TD-SCDMA), CDMA2000, Worldwide Interoperability for Microwave Access (WiMAX), Wireless Fidelity (Wi-Fi), 4^th Generation Long Term Evolution (LTE), LTE-Advance (LTE-A), or 5G NR, 6th generation (6G) mobile system standard, etc. Therefore, one skilled in the arts could readily understand that the terms used herein may also refer to their equivalents in any other infrastructure. For example, the term "UE" used herein may refer to a terminal device, a mobile device, a mobile terminal, a mobile station, a user device, a user terminal, a wireless device, a wireless terminal, or any other equivalents. For another example, the term "network node" used herein may refer to a transmission reception point (TRP), a base station, a base transceiver station, an access point, a hot spot, a NodeB, an Evolved NodeB (eNB), a gNB, a network element, a satellite, an aircraft, or any other equivalents.

Radio Link Monitoring (RLPn handling in NR

In NR, RLM is also defined for a similar purpose as in LTE i.e. monitor the downlink radio link quality of the serving cell (more precisely the SpCell, i.e. PCell and PSCell if the UE is configured with Multiple-Radio Dual Connectivity) in RRC_CONNECTED state. RLM is performed by the lower layers at the UE (LI - layer 1, physical layer). The UE performs measurements (e.g. SINR), and when its quality is poor (according to a hypothetical Physical Downlink Control Channel (PDCCH) Block Error Rate (BLER) threshold) the lower layers at the UE generate an out of sync (OOS) indication to higher layer, which maintains a counter. Similarly, when the quality improves (according to another hypothetical PDCCH Block Error Rate threshold) the UE generates an in sync (IS) indication to higher layer, which maintains another counter. These counters are used by higher layer to determine whether or not a radio link failure should be declared.

To perform these measurements to generate OOS and IS events, the UE uses reference signals. In LTE, these are the so-called Cell-specific Reference Signals (CRS) defined per cell. Differently from LTE, some level of configurability has been introduced for RLM in NR in terms of RS type I beam I RLM resource configuration and BLER thresholds for IS/OOS generation.

Explicit RLM configuration

In NR, two types of reference signals (RS Types) are defined for L3 mobility:

- PBCH/SS Block (SSB or SS Block), which basically comprises synchronization signals equivalent to PSS/SSS in LTE and PBCH/DMRS, and

- CSI-RS for L3 mobility, more configurable and configured via dedicated signalling.

There are different reasons to define the two RS types, one of them being the possibility to transmit SSBs in wide beams while CSI-RSs in narrow beams.

In NR the RS type used for RLM is also configurable and both CSI-RS based RLM and SS block based RLM are supported. In the case of CSI-RS, the time/frequency resource and sequence can be used. As there can be multiple beams, the UE needs to know which ones to monitor for RLM and how to generate IS/OOS events. In the case of SSB, each beam can be identified by an SSB index (derived from a time index in PBCH and/or a PBCH/DMRS scrambling). The network can configure by RRC signalling, X RLM resources, either related to SS blocks or CSI-RS, as follows:

- One RLM-RS resource can be either one PBCH/SS block or one CSI-RS resource/port;

- The RLM-RS resources are UE-specifically configured at least in case of CSI-RS based RLM;

- When UE is configured to perform RLM on one or multiple RLM-RS resource(s), o Periodic IS is indicated if the estimated link quality corresponding to hypothetical PDCCH BLER based on at least Y RLM-RS resource(s) among all configured X RLM-RS resource(s) is above Q_in threshold; o Periodic OOS is indicated if the estimated link quality corresponding to hypothetical PDCCH BLER based on all configured X RLM-RS resource(s) is below Q_out threshold;

■ That points in the direction that only the quality of best beam really matters at every sample to generate OOS/IS events.

Note: RLM is not defined for SCells, only for SpCells i.e. if the UE is in single connectivity, RLM is performed only on the PCell. If the UE is configured with Multi Radio - Dual Connectivity (MR-DC), RLM is performed on both the PCell and the PSCell.

Resources for RLM can be configured via RRC TS 38.331 as part of the SpCellConfig, within each dedicated BWP configuration - BWP-DowniinkDedicated, in an RRCReconfiguration or RRCResume message, within the RadioLinkMonitoringConfigl ,

Each so-called RLM resource of a SpCell that needs to be monitored is configured in the IE RadioLinkMonitoringRS, wherein the UE is configured either with an SSB index or a CSI-RS index. These resources are equivalent to the downlink beams/spatial directions transmitting the reference signals (SSBs) associated to these indexes. And each of these beams are also used for transmission of control channel(s) for that cell (e.g. PDCCH) so that performing RLM is equivalent to assess the quality of control channel for that cell.

Implicit RLM configuration According to 38.331, if an explicit list of RSs is not configured for RLM, the UE monitors the reference signal(s) configured as Quasi-co-location (QCL) of currently active TCI states configured for the PCell or PSCell. This is described in RRC in the field description below:

As described in TS 38.213, if the UE is not provided RadioLinkMonitoringRS and the UE is provided for PDCCH receptions TCI states that include one or more of a CSI- RS

- the UE uses for radio link monitoring the RS provided for the active TCI state for PDCCH reception if the active TCI state for PDCCH reception includes only one RS

- if the active TCI state for PDCCH reception includes two RS, the UE expects that one RS is configured with qd-Type set to 'typeD' [6, TS 38.214] and the UE uses the RS configured with qd-Type set to 'typeD' for radio link monitoring; the UE does not expect both RS to be configured with qd-Type set to 'typeD'

- the UE is not required to use for radio link monitoring an aperiodic or semi- persistent RS

- For L_max = 4, the UE selects the N_RLM RS provided for active TCI states for PDCCH receptions in CORESETs associated with the search space sets in an order from the shortest monitoring periodicity. If more than one CORESETs are associated with search space sets having same monitoring periodicity, the UE determines the order of the CORESET from the highest CORESET index as described in clause 10.1.

The RS for a TCI state is configured as follows:

And, the TCI state is considered activated based on reception of MAC CE(s) (see TS 38.321 for further details on MAC CE activation of TCI states).

Out of Sync COOS) and In Sync (IS) indications based on RLM resources

For both implicit and explicit RLM configurations, the UE performs monitoring of the resources and evaluates the conditions whether radio link is suitable for the RRC connection or not.

In non-DRX mode operation, the physical layer in the UE assesses once per indication period the radio link quality, evaluated over the previous time period defined in [TS 38.133] against thresholds (Q_0Mt and Q_in) configured by rimlnSyncOutOfSyncThreshoid. The UE determines the indication period as the maximum between the shortest periodicity for radio link monitoring resources and 10 msec.

In DRX mode operation, the physical layer in the UE assesses once per indication period the radio link quality, evaluated over the previous time period defined in [10, TS 38.133], against thresholds Q_out and Q_in) provided by rimlnSyncOutOfSyncThreshoid. The UE determines the indication period as the maximum between the shortest periodicity for radio link monitoring resources and the DRX period.

The physical layer in the UE indicates, in frames where the radio link quality is assessed, out-of-sync (OOS) to higher layers when the radio link quality is worse than the threshold Q_out for all resources in the set of resources for radio link monitoring. When the radio link quality is better than the threshold Q_in for any resource in the set of resources for radio link monitoring, the physical layer in the UE indicates, in frames where the radio link quality is assessed, in-sync to higher layers.

Radio Link Failure due to physical layer problems

Fig. 1 is a diagram illustrating an exemplary procedure for declaring an RLF. As shown in Fig. 1, the procedure is started with step or stage S110 where a UE may perform normal operations, for example, when its radio condition is good. In some embodiments, the higher layer (RRC) may receive the OOS and IS indications from the lower layers (LI, physical layer), as described above. For example, at step or stage S120, the higher layer may receive one or more OOS indications from the lower layers. After a configurable number (N310) of such consecutive OOS indications are received, a timer (T310) may be started at the end of step or stage S120 where step or stage S130 begins. If the link quality is not improved (recovered) while T310 is running (i.e. there are no N311 consecutive "in-sync" indications from the physical layer) during step or stage S130, a radio link failure (RLF) may be declared in the UE at the end of step or stage S130 where step or stage S140 begins and another timer (T311) may be started.

At step or stage S140, upon declaring an RLF in the PCell, the UE may initiate reestablishment or, if configured with MR-DC and if configured with MCG failure reporting, it may report an MCG failure to the PSCell. Upon declaring an RLF in the PSCell (also named S-RLF), the UE may initiate an SCG Failure Report via the PCell. When the timer T311 expires and the re-establishment procedure is not successfully finished, the UE may go to the RRC_IDLE state at step or stage S150.

L1-L2 based inter-cell mobility in Rel-18

In Rel-18, 3GPP has agreed on a Work Item on Further New Radio (NR) mobility enhancements, in particular, in a technical area entitled L1/L2 based inter-cell mobility. See the WI description (WID in RP-213565 (https://www.3gpp.Org/ftp/TSG_RAN/TSG_RAN/TSGR_94e/Docs//RP-213565.zip) for further details.

According to the WID, when the UE moves from the coverage area of one cell to another cell, at some point a serving cell change needs to be performed. Currently serving cell change is triggered by L3 measurements and is done by RRC signalling triggered Reconfiguration with Synchronisation for change of PCell and PSCell, as well as release/add for SCells when applicable. All cases involve complete L2 (and LI) resets, leading to longer latency, larger overhead and longer interruption time than beam switch mobility. The goal of L1/L2 mobility enhancements is to enable a serving cell change via L1/L2 signalling, in order to reduce the latency, overhead and interruption time.

L1-L2 inter-cell mobility should be, if possible, like an inter-cell beam management i.e. to support L1-L2 inter-cell mobility the UE should be configured to perform measurements on cells which are not the serving cells as defined up to Rel-17.

In Rel-17, to support inter-PCI mTRP operation, a solution has been standardized where a CSI resource may be associated to a PCI which is not the same PCI of one of the serving cells. That solution also requires the UE to receive an explicit indication of which beams (SSBs) and PCIs to be measured for a given reporting configuration.

The goal is to specify mechanism and procedures of L1/L2 based inter-cell mobility for mobility latency reduction: o Configuration and maintenance for multiple candidate cells to allow fast application of configurations for candidate cells [RAN2, RAN3] o Dynamic switch mechanism among candidate serving cells (including SpCell and SCell) for the potential applicable scenarios based on L1/L2 signalling [RAN2, RANI] o LI enhancements for inter-cell beam management, including LI measurement and reporting, and beam indication [RANI, RAN2] o Timing Advance management [RANI, RAN2] o CU-DU interface signaling to support L1/L2 mobility, if needed [RAN3]

FR2 specific enhancements are not precluded, if any.

The procedure of L1/L2 based inter-cell mobility are applicable to the following scenarios:

■ Standalone, CA and NR-DC case with serving cell change within one CG

■ Intra-DU case and intra-CU inter- DU case (applicable for Standalone and CA: no new RAN interfaces are expected)

■ Both intra-frequency and inter-frequency

■ Both FR1 and FR2

■ Source and target cells may be synchronized or non-synchronized RLF detection has been defined to allow the UE to detect a failure and perform autonomous mobility (cell selection followed by an RRC Reestablishment procedure), e.g., when something does not work properly in the transmission of an RRC Measurement report from the UE to the network or in the reception of the response to that report: an RRC Reconfiguration including the IE Reconfiguration with Sync (handover command). This may occur, for example, when the measurement triggers are not optimally tuned.

Fig. 2 is a diagram illustrating an exemplary telecommunication network 20 in which a UE 200 leaves a coverage area of L1/L2 inter-cell mobility candidate cells 201 through 204 and in which joint RLF detection for L1/L2 inter-cell mobility is applicable according to an embodiment of the present disclosure.

In L1/L2 inter-cell mobility, the UE 200 may be configured with one or more L1/L2 inter-cell mobility candidate cells 201 through 204 (e.g. each associated to a physical cell identifier, such as PCI-1, PCI-2, PCI-3, PCI-4), which are the cells the UE 200 may be indicated by the network to move to upon reception of a lower layer signaling, such as a MAC CE or DCI, indicating one of the configured L1/L2 inter-cell mobility candidate cells 201 through 204. However, most likely the UE 200 will be configured with a finite number of L1/L2 inter-cell mobility candidate cells, i.e., there will always be some limit or border wherein the UE 200 reaches a cell which has not been configured as a L1/L2 inter-cell mobility candidate. In addition, because L1/L2 inter-cell mobility is only meant to be supported for intra-CU scenarios, all candidate cells needs to be controlled by the same or different DU(s) of the same CU. So even if the UE 200 could add candidates, it is not possible if the cell the UE 200 is entering the coverage of (e.g. cell 20x with PCI-x) is associated to another CU.

In this case, RRC-based mobility to the cell 20x of PCI-x is needed. Thus, as discussed above, the fact that RRC-based mobility needs to be supported, at least in these cases the UE 200 leaves the coverage of all configured L1/L2 inter-cell mobility candidates 201 through 204, an RLF mechanism is needed to detect a radio failure for a UE 200 configured with one or more L1/L2 inter-cell mobility candidate(s) is needed, as the RRC measurement reporting framework may not always work.

The existing solution for RLF detection in 5G NR due to radio related problems rely on an RLM process based on the monitoring of the Special Cell (SpCell), such as the PCell in the Master Cell Group (MCG), or the PSCell in the Secondary Cell Group (SCG). However, in L1/L2 inter-cell mobility, the UE is not only configured with a SpCell, but in addition, with one or more L1/L2 inter-cell mobility candidates which the UE can move to with L1/L2 inter-cell mobility execution. Hence, the existing framework for RLF detection and RLM may not be suitable, as the UE may actually leave the coverage of the SpCell it connects in the transitions to RRC_CONNECTED, but still be in the coverage of one of the L1/L2 inter-cell mobility candidate cells i.e. in the existing solution the UE would declare RLF even though it is still in the coverage in which it is capable of moving using inter-cell beam management operations. These undesirable (and unnecessary) RLFs and RRC Re-establishment procedures, which degrades the Key Performance Indicators at the network side, increases the signaling, reduces the control at the network side for L1/L2 inter-cell mobility.

Therefore, some embodiments of the present disclosure provide methods at a UE configured with one or more L1/L2 inter-cell mobility candidate cell(s) for performing RLM and RLF detection. The method comprises:

- Receiving one or more L1/L2 inter-cell mobility candidate cell config u ration (s);

- Performing a single RLM process based on one or more of: o A serving cell configuration; and/or o One of the L1/L2 inter-cell mobility candidate cell configuration(s);

- Upon reception of a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, and performing one or more of the actions: o (Solution 1) If the UE performs the single RLM process based on the serving cell configuration, the UE updates the RLM process to be according to the L1/L2 inter-cell mobility candidate cell; o (Solution 2) if the UE performs the single RLM process based on parameters of a serving cell and parameter(s) of at least one L1/L2 inter-cell mobility candidate cell (joint RLM), at least one state or parameter in the RLM process continues.

In some embodiments, a UE configured with a serving cell and one or more L1/L2 inter-cell mobility candidate cells may perform a single RLM process and, while performing RLM, the UE may receive a lower layer signaling indicating the execution of L1/L2 inter-cell mobility to a L1/L2 inter-cell mobility candidate cell.

Then, different solutions may be proposed: - Solution 1) while the UE performs an RLM process based on a serving cell the UE may receive a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, upon which the UE may update the RLM process to be according to the target candidate cell.

- Solution 2) UE may perform an RLM process based on parameters of a serving cell and parameter(s) of at least one L1/L2 inter-cell mobility candidate cell (called, in the present disclosure, joint RLM), when it receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to the L1/L2 inter-cell mobility candidate cell, without updating the RLM process.

In some embodiments, it is possible to detect an RLF when the UE is configured with one or more L1/L2 inter-cell mobility candidate cells the UE can move to with L1/L2 inter-cell mobility execution. Hence, when the UE leaves the coverage of the SpCell it connects in the transitions to RRC_CONNECTED, but is still in the coverage of one of the L1/L2 inter-cell mobility candidate cells i.e. the UE would not declare RLF if still in the coverage in which it is capable of moving using inter-cell beam management operations.

The text refers to the term "L1/L2 based inter-cell mobility" as used in the Work Item Description (WID) in 3GPP, though it interchangeably also uses the terms L1/L2 mobility, Ll-mobility, LI based mobility, Ll/L2-centric inter-cell mobility or L1/L2 intercell mobility. The basic principle is that the UE receives a lower layer signaling from the network indicating to the UE a change of its serving cell (e.g. change of PCell, from a source to a target PCell), wherein a lower layer signaling is a message/ signaling of a lower layer protocol.

In some embodiments, a lower layer protocol refers to a lower layer protocol in the air interface protocol stack compared to RRC protocol, e.g. Medium Access Control (MAC) is considered a lower layer protocol as it is "below" RRC in the air interface protocol stack, and in this case a lower layer signaling/ message may correspond to a MAC Control Element (MAC CE). Another example of lower layer protocol is the Layer 1 (or Physical Layer, LI), and in this case a lower layer signaling/message may correspond to a Downlink Control Information (DCI).

Signaling information in a protocol layer lower than RRC reduces the processing time and, consequently, reduces the interruption time during mobility; in addition, it may also increase the mobility robustness as the network may respond to faster changes in the channel conditions. Another relevant aspect in L1/L2 inter-cell mobility is that in multi-beam scenario, a cell can be associated to multiple SSBs, and during a half-frame, different SSBs may be transmitted in different spatial directions (i.e. using different beams, spanning the coverage area of a cell). Similar reasoning may be applicable to CSI-RS resources, which may also be transmitted in different spatial directions. Hence, in L1/L2 inter-cell mobility, the reception of a lower layer signaling indicates the UE to change from one beam in the serving cell, to another beam in a neighbour cell (which is a configured candidate cell), and by that changing serving cell.

The text refers to the term "L1/L2 inter-cell mobility candidate cell" to refer to a cell the UE is configured with when configured with L1/L2 inter-cell mobility, that is, a cell the UE can move to in a L1/L2 inter-cell mobility procedure, upon reception of a lower layer signaling. These cells may also be called candidate cells, candidates, mobility candidates, non-serving cells, additional cells, etc. In some embodiments, this is a cell the UE perform measurements on (e.g. CSI measurements) as disclosed in the present disclosure, so that the UE reports these measurements and network may take educated decision on which beam (e.g. TCI state) and/or cell the UE is to be switched to. A L1/L2 inter-cell mobility candidate cell may be a candidate to be a target PCell or PSCell, or an SCell of a cell group (e.g. MCG SCell).

In some embodiments, a serving cell may correspond to a cell whose serving cell configuration has a TCI state which is activated. That may be a serving cell the UE is configured with when the UE transition to RRC_CONNECTED, or a cell the UE moves to with an RRC Reconfiguration with sync procedure (or handover) or a cell the UE moves to with a L1/L2 inter-cell mobility execution.

In some embodiments, a L1/L2 inter-cell mobility candidate cell may be a cell the UE is configured with for L1/L2 inter-cell mobility, i.e., after the configuration, the UE may receive a lower layer signaling (e.g. MAC CE or DCI) indicating the execution of L1/L2 inter-cell mobility to that configured cell. In some embodiments, that may be called a serving cell, though that is not "activated" if the UE does not have an activated TCI state of that cell. In some other embodiments, that is not called a serving cell, but simply a candidate or non-serving cell the UE is configured with for L1/L2 inter-cell mobility.

As highlighted above there are two solutions proposed, reflecting different sets of embodiments. In some embodiments, when a L1/L2 inter-cell mobility candidate cell is configured at the UE by a source network node (e.g., the Serving DU or Candidate DU), the configuration may include an indication on whether the RLF timers and/or RLF counters should be kept or reset when receiving a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell. This basically means that the Serving DU and the Candidate DU can decide independently in their configuration to reset or keep the RLF timers and RLF counters. Bottomline is that the UE always follow the indication present in the configuration of the L1/L2 inter-cell mobility candidate cell indicated in the lower layer signaling indicating L1/L2 inter-cell mobility execution.

In some embodiments, it is a third network node (e.g., a Central Unit - CU) that decides on whether the UE should keep or reset the RLF timer and/or RLF counter when receiving a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell. This means that when receiving the RRC message from the third network node with a configuration for a L1/L2 inter-cell mobility candidate cell, the RRC message may further comprise an indication on whether the UE should keep or reset the RLF timer and/or RLF counter when receiving a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell. This means that the indication configures a behavior at the UE that does not change when receiving a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell. It is only the CU that can change this behaviour at the UE via a reconfiguration.

Solution 1

In some embodiments, while the UE performs an RLM process based on a serving cell the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, upon which the UE may update the RLM process to be according to the target candidate cell.

- (Handling of RLM-RSs) In some embodiments, the UE may perform an RLM process by monitoring a first set of RLM-RS(s) of the serving cell, and when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may monitor a second set of RLM-RS(s) of the target candidate cell. It may be considered that there is a switching in the RLM process from source to target. (Update of implicit RLM) In some embodiments, the first set of RLM-RS(s) of the serving cell may comprise one or more beams which are being used for the transmissions in the serving cell of control (e.g. PDCCH) and data channels e.g. PDSCH. (Update of implicit RLM) In some embodiments, the first RLM-RS(s) of the serving cell may comprise one or more SSBs and/or CSI-RSs configured as QCL source of the currently activated TCI state(s) of the serving cell e.g. unified TCI state (as defined in TS 38.213, or PDCCH TCI state). (Update of implicit RLM) In some embodiments, the second set of RLM-RS(s) of the target candidate cell may comprise one or more beams which are being activated for the transmissions of control (e.g. PDCCH) and data channels e.g. PDSCH in the target candidate cell, e.g., as indicated in the lower layer signaling for the L1/L2 inter-cell mobility execution. (Update of implicit RLM) In some embodiments, the second set of RLM-RS(s) of the target candidate cell may comprise one or more SSBs and/or CSI-RS configured as QCL source of the TCI state(s) of the target candidate cell which are being activated, e.g., as indicated in the lower layer signaling for the L1/L2 inter-cell mobility execution. (Update of explicit RLM) In some embodiments, the first set of RLM-RS(s) of the serving cell may comprise one or more beams configured in the serving cell configuration e.g. as part of a BWP configuration. (Update of explicit RLM) In some embodiments, the first set of RLM-RS(s) of the serving cell may comprise one or more SSBs and/or CSI-RS configured in the serving cell configuration e.g. as part of a BWP configuration. (Update of explicit RLM) In some embodiments, the second set of RLM-RS(s) of the target candidate cell may comprise one or more beams configured in the target candidate cell configuration of the cell indicated in the lower layer signaling for the L1/L2 inter-cell mobility execution. (Update of explicit RLM) In some embodiments, the second set of RLM-RS(s) of the target candidate cell may comprise one or more SSBs and/or CSI-RSs configured in the target candidate cell configuration of the cell indicated in the lower layer signaling for the L1/L2 inter-cell mobility execution. - (Generating Out of Sync (OOS) indications/events) In some embodiments, the UE (e.g. the lower layers at the UE) may generate an OOS indication if all RLM-RS(s) in the first set of RLM-RS(s) of the serving cell are worse than a configured threshold, e.g. a mapped Block Error Rate of a control channel.

- (Stopping RLF timers la) In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may stop an RLF timer (e.g. stop timer T310 as defined in TS 38.331), if running. By stopping the timer T310 the UE may prevent RLF to be triggered while the UE is executing L1/L2 inter-cell mobility i.e. while a counter-action is being taken for a possible problem i.e. it is advantageous to first wait until the action is perform and not trigger the actions upon an RLF detection prematurely. o In some embodiments, the UE may stop using the value of RLF timer (value of T310) in the serving cell configuration and start to use the value of the RLF timer in the L1/L2 inter-cell mobility candidate cell configuration indicated in the lower layer signaling for L1/L2 inter-cell mobility execution.

- (Keep running RLF timers lb) In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE does not stop the RLF timers (e.g. T310, as defined in TS 38.331), if running. By NOT stopping the timer T310 the UE may prevent RLF to be triggered too late. If the UE is performing L1/L2 inter-cell mobility to a cell which is anyways not in good enough radio conditions, an RLF will anyways happens, being just a matter of time, thus, it is advantageous that it is not triggered late. o In some embodiments, the UE may keep the RLF timer running during the execution of L1/L2 inter-cell mobility to the target cell. However, in this case the running RLF timer (e.g., T310) will be stopped when receiving at least "N" consecutive in-sync indications from lower layers for the target cell. In this case "N" can be the N311 counter as specified in TS 38.331. In this case the UE may reset the counter N311 when receiving the lower layer signaling but keep the timer T310 running. o In some embodiments, the UE may keep the RLF timer running during the execution of L1/L2 inter-cell mobility to the target cell. However, in this case the running RLF timer (e.g., T310) will be stopped when receiving at least "N" consecutive in-sync indications from lower layers of the serving cell and the target cell. In this case "N" can be the N311 counter as specified in TS 38.331. In this case the UE does not reset the counter N311 when receiving the lower layer signaling, meaning that the overall number "N" of in-sync indication is the sum of those one received first on the serving cell and then on the target cell (i.e., after executing L1/L2 inter-cell mobility over the target cell).

- (Resetting of RLF counters la) In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may reset at least one RLF related counter, such as N310 and/or N311. By resetting N310, for example, the UE may prevent RLF to be triggered while the UE is executing L1/L2 inter-cell mobility i.e. while a counter-action is being taken for a possible problem i.e. it is advantageous to first wait until the action is perform and not trigger the actions upon an RLF detection prematurely. o In some embodiments, the UE may stop using the value of RLF counter (value of N310) in the serving cell configuration and start to use the value of the RLF counter in the L1/L2 inter-cell mobility candidate cell configuration indicated in the lower layer signaling for L1/L2 inter-cell mobility execution.

- (Keep state of RLF counters lb) In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may keep the state of an RLF related counter, such as N310 and/or N311. This means that the UE will increment or reset the current values of the RLF related counters according to the in-sync or out-of-sync indication from lower layer with respect to the target cell. For example, if the values of the RLF related counter was N310 = 2 and N311= 0 when the UE was in the serving cell, after receiving the L1/L2 inter-cell mobility lower layer command and switching to the target cell, if the UE receives an out-of-sync indication from the lower layer while connected to the target cell, the UE may update the values of the RLF timer to N310=3 and N311=0. o In some embodiments, the UE may keep the state of the RLF related counter during the execution of L1/L2 inter-cell mobility to the target cell. However, in this case, if the timer T310 is running, the UE will keep timer T310 running and will stop it only when receiving at least "N" consecutive in-sync indications from lower layers for the target cell. - (Detection of L1/L2 inter-cell mobility failure) In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may start a timer Txxx and send a message (e.g. MAC CE or Scheduling request) to the indicated L1/L2 inter-cell mobility candidate cell. If the UE receives a response message (e.g. a HARQ feedback, another form of acknowledgement and/or a response message) while the timer is running, the UE may stop the timer and considers the process successful; Else, if the timer expires, the UE may consider the L1/L2 inter-cell mobility as a failed procedure. Notice that the failure handling mechanisms is useful in this case as RLM stops in the serving cell and, while the timer is running, it is not started. In other words, RLM would only re-start, according to the configuration of the target candidate cell, after the UE receives the response from the network, after the L1/L2 inter-cell mobility execution.

- (Actions upon RLF detection) In some embodiments, if the UE detects RLF at a Master Cell Group (MCG), according to a method in the present disclosure, the UE may initiate an RRC Re-establishment procedure. An RLF at the MCG, or M-RLF, means that the UE is monitoring a PCell as the Special Cell.

- (Actions upon RLF detection) In some embodiments, if the UE detects RLF at a Secondary Cell Group (SCG), according to a method in the document, the UE may initiate an SCG Failure Report procedure e.g. to the network node operating as Master Node for a UE configured with Multi-Radio Dual Connectivity (MR-DC). An RLF at the SCG, or S-RLF, means that the UE is monitoring a PSCell (Special cell of the SCG) as the Special Cell.

Solution 2

In some embodiments, a UE may perform an RLM process based on parameters of a serving cell and parameter(s) of at least one L1/L2 inter-cell mobility candidate cell (called, in the present disclosure, joint RLM), when it receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to the L1/L2 inter-cell mobility candidate cell, without updating the RLM process.

- (Handling of RLM-RSs 2a) In some embodiments, the UE may perform an RLM process by monitoring a single set of RLM-RS(s), comprising at least one RLM-RS(s) of the serving cell and at least one RLM-RS(s) of a L1/L2 inter-cell mobility candidate cell the UE is configured with. And, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may continue to monitor the single set of RLM-RS(s) despite the execution of L1/L2 inter-cell mobility to a new cell. o In some embodiments, the UE may determine the at least one RLM-RS(s) for the serving cell, comprised in the single set of RLM-RSs, by receiving the RLM-RSs configured for the current active BWP of the serving cell. o In some embodiments, the UE may determine the at least one RLM-RS(s) for the serving cell as the beam(s) configured as QCL source of an activated TCI state of the serving cell. o In some embodiments, the UE may determine the at least one RLM-RS(s) for the serving cell as the SSB(s) and/or CSI-RS resources configured as QCL source of an activated TCI state of the serving cell. o In some embodiments, the UE may determine RLM-RS(s) for a L1/L2 intercell serving cell, comprised in the single set of RLM-RSs, by receiving the RLM-RSs configured for a BWP of the target candidate cell configuration. o In some embodiments, the UE may determine RLM-RS(s) for a L1/L2 intercell mobility candidate cell, comprised in the single set of RLM-RSs, by receiving the RSs configured as QCL source of TCI states of the target candidate cell configuration. o In some embodiments, the single set of RLM-RS(s) may comprise at least one beam (e.g. SSB and/or CSI-RS) of all L1/L2 inter-cell mobility candidate cells. o In some embodiments, the single set of RLM-RS(s) may comprise at least one beam (e.g. SSB and/or CSI-RS) of L1/L2 inter-cell mobility candidate cells explicitly indicated in a configuration, which may be a subset of all L1/L2 inter-cell mobility candidate cells the UE is configured with. o In some embodiments, the single set of RLM-RS(s) may be re-configured by the network. For example, the UE may have added to the set of RLM-RS one or more SSBs and/or CSI-RS resources of the L1/L2 inter-cell mobility candidate cell, after the execution of the L1/L2 inter-cell mobility e.g. by receiving an RRC Reconfiguration. o In some embodiments, the single set of RLM-RS(s) may have RLM-RSs activated and/or deactivated e.g. by the UE receiving a MAC CE and/or DCI from the network. For example, the UE may have activated to the set of RLM-RS one or more SSBs and/or CSI-RS resources of the L1/L2 inter-cell mobility candidate cell, after the execution of the L1/L2 inter-cell mobility, and/or the deactivation of RLM-RSs of the cell which was the serving cell before the L1/L2 inter-cell mobility execution. o In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may consider the at least one RLM-RS(s) of a L1/L2 inter-cell mobility candidate cell as the RLM-RS(s) of the serving cell and the at least one RLM-RS(s) of the serving cell as the RLM-RS(s) of a L1/L2 intercell mobility candidate cell. o In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may consider the at least one RLM-RS(s) of a L1/L2 inter-cell mobility candidate cell as the RLM-RS(s) of the serving cell and at least one new RLM-RS(s) of a L1/L2 inter-cell mobility candidate cell wherein the L1/L2 inter-cell mobility candidate cell may be different from the previous serving cell.

- (Generating Out of Sync (OOS) indications/ events) In some embodiments, the UE (e.g. the lower layers at the UE) may generate an OOS indication if all RLM-RS(s) in the single set of RLM-RS(s) of the serving cell are worse than a configured threshold e.g. a mapped Block Error Rate of a control channel.

- (Handling of RLM-RSs 2b) In some embodiments, the UE may perform an RLM process by monitoring a single set of RLM-RS(s), comprising at least one RLM-RS(s) of the serving cell and at least one RLM-RS of a L1/L2 inter-cell mobility candidate cell the UE is configured with. And, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may continue to monitor the single set of RLM-RS(s) only if the single set of RLM-RS(s) comprises at least one RLM-RS of the indicated L1/L2 inter-cell mobility candidate cell.

- (Stopping RLF timers) In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may stop an RLF timer (e.g. stops timer T310 as defined in TS 38.331), if running. By stopping the timer T310 the UE prevents RLF to be triggered while the UE is executing L1/L2 inter-cell mobility i.e. while a counter-action is being taken for a possible problem i.e. it is advantageous to first wait until the action is perform and not trigger the actions upon an RLF detection prematurely. In one embodiment, the UE may stop using the value of RLF timer (value of T310) in the serving cell configuration and start to use the value of the RLF timer in the L1/L2 intercell mobility candidate cell configuration indicated in the lower layer signaling for L1/L2 inter-cell mobility execution. Notice that despite the fact that the UE uses a single set of RLM-RSs, there may still be different RLF timer values, per cell, which is updated upon L1/L2 inter-cell mobility execution.

- (Keep running RLF timers) In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE does not stop the RLF timers (e.g. T310, as defined in TS 38.331), if running. By NOT stopping the timer T310 the UE prevents RLF to be triggered too late. If the UE is performing L1/L2 inter-cell mobility to a cell which is anyways not in good enough radio conditions, an RLF will anyways happens, being just a matter of time, thus, it is advantageous that it is not triggered late. o In some embodiments, the UE may keep the RLF timer running during the execution of L1/L2 inter-cell mobility to the target cell. However, in this case the running RLF timer (e.g., T310) will be stopped when receiving at least "N" consecutive in-sync indications from lower layers for the target cell. In this case "N" can be the N311 counter as specified in TS 38.331. In this case the UE may reset the counter N311 when receiving the lower layer signaling but keep the timer T310 running. o In some embodiments, the UE may keep the RLF timer running during the execution of L1/L2 inter-cell mobility to the target cell. However, in this case the running RLF timer (e.g., T310) will be stopped when receiving at least "N" consecutive in-sync indications from lower layers of the serving cell and the target cell. In this case "N" can be the N311 counter as specified in TS 38.331. In this case the UE does not reset the counter N311 when receiving the lower layer signaling, meaning that the overall number "N" of in-sync indication is the sum of those one received first on the serving cell and then on the target cell (i.e., after executing L1/L2 inter-cell mobility over the target cell). - (Resetting of RLF counters) In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may reset at least one RLF related counter, such as N310 and/or N311. By resetting N310, for example, the UE may prevent RLF to be triggered while the UE is executing L1/L2 inter-cell mobility i.e. while a counter-action is being taken for a possible problem i.e. it is advantageous to first wait until the action is perform and not trigger the actions upon an RLF detection prematurely. In one embodiment, the UE may stop using the value of RLF counter (value of N310) in the serving cell configuration and starts to use the value of the RLF counter in the L1/L2 inter-cell mobility candidate cell configuration indicated in the lower layer signaling for L1/L2 inter-cell mobility execution.

- (Keep state of RLF counters lb) In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may keep the state of an RLF related counter, such as N310 and/or N311. This means that the UE will increment or reset the current values of the RLF related counters according to the in-sync or out-of-sync indication from lower layer with respect to the target cell. For example, if the values of the RLF related counter was N310 = 2 and N311= 0 when the UE was in the serving cell, after receiving the L1/L2 inter-cell mobility lower layer command and switching to the target cell, if the UE receives an out-of-sync indication from the lower layer while connected to the target cell, the UE updates the values of the RLF timer to N310=3 and N311=0. o In some embodiments, the UE may keep the state of the RLF related counter during the execution of L1/L2 inter-cell mobility to the target cell. However, in this case, if the timer T310 is running, the UE will keep timer T310 running and will stop it only when receiving at least "N" consecutive in-sync indications from lower layers for the target cell.

- (Detection of L1/L2 inter-cell mobility failure) In some embodiments, when the UE receives a lower layer signaling indicating L1/L2 inter-cell mobility execution to a L1/L2 inter-cell mobility candidate cell, the UE may start a timer Txxx and sends a message (e.g. MAC CE or Scheduling request) to the indicated L1/L2 inter-cell mobility candidate cell. If the UE receives a response message (e.g. a HARQ feedback, another form of acknowledgement and/or a response message) while the timer is running, the UE may stop the timer and consider the process successful; Else, if the timer expires, the UE may consider the L1/L2 inter-cell mobility as a failed procedure. Notice that the failure handling mechanisms is useful in this case as RLM stops in the serving cell and, while the timer is running, it is not started. In other words, RLM would only re-start, according to the configuration of the target candidate cell, after the UE receives the response from the network, after the L1/L2 inter-cell mobility execution.

- (Actions upon RLF detection) In some embodiments, if the UE detects RLF at a Master Cell Group (MCG), according to a method in the document, the UE may initiate an RRC Re-establishment procedure. An RLF at the MCG, or M-RLF, means that the UE is monitoring a PCell as the Special Cell.

Fig. 3 is a flow chart illustrating an exemplary method 300 at a UE for RLM according to an embodiment of the present disclosure. The method 300 may be performed at a UE (e.g., the UE 200). In some embodiments, the UE may be configured with one or more candidate cells for L1/L2 inter-cell mobility. The method 300 may comprise steps S310 and S320. However, the present disclosure is not limited thereto. In some other embodiments, the method 300 may comprise more steps, less steps, different steps, or any combination thereof. Further the steps of the method 300 may be performed in a different order than that described herein when multiple steps are involved. Further, in some embodiments, a step in the method 300 may be split into multiple sub-steps and performed by different entities, and/or multiple steps in the method 300 may be combined into a single step. The method 300 may begin at step S310 where the UE may perform an RLM process based on at least one of a first configuration associated with a serving cell and at least one second configuration associated with at least one of the candidate cells.

At step S320, the UE may continue the RLM process with or without an update of one or more parameters that are configured for the RLM process in response to receiving a signaling indicating L1/L2 inter-cell mobility execution to a target cell.

In some embodiments, the continuing the RLM process with an update of one or more parameters that are configured for the RLM process may comprise: updating the one or more parameters based on at least a configuration associated with the target cell in response to the RLM process being performed based not on the second configuration; and continuing the RLM process with the updated parameters. In some embodiments, the performing the RLM process based on at least one of the first configuration and the second configuration may comprise: performing the RLM process by monitoring a first set of RLM-RSs of the serving cell. In some embodiments, the updating the one or more parameters based on at least the configuration associated with the target cell may comprise: updating the first set of RLM-RSs of the serving cell with a second set of RLM- RSs indicated by the configuration associated with the target cell. In some embodiments, the continuing the RLM process with the updated parameters may comprise: continuing the RLM process by monitoring the second set of RLM-RSs.

In some embodiments, the first set of RLM-RSs may comprise at least one of: one or more reference signals associated with one or more beams that are being used for transmission of one or more control and/or data channels in the serving cell; one or more SSBs configured as QCL source of one or more currently activated TCI states of the serving cell; one or more CSI-RSs configured as QCL source of one or more currently activated TCI states of the serving cell; one or more reference signals associated with one or more beams indicated by the first configuration; one or more SSBs indicated by the first configuration; and one or more CSI-RSs indicated by the first configuration.

In some embodiments, the second set of RLM-RSs may comprise at least one of: one or more reference signals associated with one or more beams that are being activated for transmission of one or more control and/or data channels in the target cell; one or more SSBs configured as QCL source of one or more TCI states of the target cell that are being activated; one or more CSI-RSs configured as QCL source of one or more TCI states of the target cell that are being activated; one or more reference signals associated with one or more beams indicated by the configuration associated with the target cell; one or more SSBs indicated by the configuration associated with the target cell; and one or more CSI-RSs indicated by the configuration associated with the target cell.

In some embodiments, the method 300 may further comprise: generating an OOS indication in response to determining that measurements on all RLM-RSs in the first set are worse than a configured threshold. In some embodiments, the continuing the RLM process without an update of one or more parameters that are configured for the RLM process may comprise: continuing the RLM process by continuing to use the one or more parameters in response to the RLM process being performed based on the first configuration and the second configuration. In some embodiments, the performing the RLM process based on at least one of the first configuration and the second configuration may comprise: performing the RLM process by monitoring a single set of RLM-RSs that comprise at least one RLM-RS of the serving cell and at least one RLM-RS of a candidate cell the UE is configured with. In some embodiments, the continuing the RLM process by continuing to use the one or more parameters may comprise: continuing the RLM process by continuing to monitor the single set of RLM-RSs.

In some embodiments, the single set of RLM-RSs may comprise at least one of: one or more RLM-RSs configured for a current active BWP of the serving cell; one or more reference signals associated with one or more beams configured as QCL source of an activated TCI state of the serving cell; one or more SSBs configured as QCL source of an activated TCI state of the serving cell; one or more CSI-RSs configured as QCL source of an activated TCI state of the serving cell; one or more RLM-RSs configured for a BWP of the configuration associated with the target cell; one or more reference signals configured as QCL source of one or more TCI states of the configuration associated with the target cell; one or more reference signals associated with at least one beam of all candidate cells; and one or more reference signals associated with at least one beam of one or more candidate cells that are explicitly indicated in a configuration. In some embodiments, the method 300 may further comprise: receiving, from the target cell, a configuration indicating one or more SSBs and/or CSI-RS resources to be monitored; and reconfiguring the single set of RLM-RSs based on at least the received configuration. In some embodiments, the method 300 may further comprise at least one: activating one or more RLM-RSs in the single set; and deactivating one or more RLM- RSs in the single set. In some embodiments, the activating one or more RLM-RSs in the single set may comprise: activating one or more RLM-RSs in the single set that are associated with the target cell in response to the execution of the L1/L2 inter-cell mobility to the target cell. In some embodiments, the deactivating one or more RLM- RSs in the single set may comprise: deactivating one or more RLM-RSs in the single set that are associated with the serving cell before the execution of the L1/L2 inter-cell mobility to the target cell. In some embodiments, the method 300 may further comprise at least one of: determining the at least one RLM-RS in the single set that is associated with the candidate cell as at least one RLM-RS of the serving cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell; and determining the at least one RLM-RS in the single set that is associated with the serving cell as at least one RLM-RS of the candidate cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

In some embodiments, the method 300 may further comprise: determining the at least one RLM-RS in the single set that is associated with the candidate cell as at least one RLM-RS of the serving cell and also at least one RLM-RS of a candidate cell that is different from the serving cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method 300 may further comprise: generating an OOS indication in response to determining that measurements on all RLM-RSs in the single set are worse than a configured threshold.

In some embodiments, the continuing to monitor the single set of RLM-RSs is performed only in response to determining that the single set of RLM-RSs may comprise at least one RLM-RS of the target cell. In some embodiments, the method 300 may further comprise: stopping an RLF timer associated with the RLM process in response to: determining that the RLF timer is running; and receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method 300 may further comprise: starting another RLF timer with a value indicated in the configuration associated with the target cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

In some embodiments, the method 300 may further comprise: continuing to use an RLF timer associated with the RLM process in response to: determining that the RLF timer is running; and receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method 300 may further comprise: stopping the RLF timer in response to: determining that the RLF timer is running; and receiving at least a configured number of consecutive IS indications from a lower layer of the UE for the target cell. In some embodiments, the method 300 may further comprise: resetting an RLF counter associated with the RLF timer while continuing to use the RLF timer in response to: determining that the RLF timer is running; and receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

In some embodiments, the method 300 may further comprise: stopping the RLF timer in response to: determining that the RLF timer is running; and receiving at least a configured number of consecutive IS indications from a lower layer of the UE for the serving cell and the target cell. In some embodiments, the method 300 may further comprise: continuing to use the RLF timer without resetting an RLF counter associated with the RLF timer in response to: determining that the RLF timer is running; and receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method 300 may further comprise: resetting an RLF counter associated with the RLM process in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the resetting the RLF counter may comprise: resetting the value of the RLF counter to a corresponding value indicated by the configuration associated with the target cell.

In some embodiments, the method 300 may further comprise: continuing to use an RLF counter associated with the RLM process in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method 300 may further comprise: stopping an RLF timer associated with the RLF counter, only in response to: determining that the RLF timer is running; and receiving at least a configured number of consecutive IS indications from a lower layer of the UE for the target cell. In some embodiments, the RLF counter may be the N310 counter or the N311 counter. In some embodiments, the RLF timer may be the T310 timer.

In some embodiments, the method 300 may further comprise at least one of: stopping or suspending the RLM process in the serving cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell; starting a timer in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell; and transmitting, to a network node associated with the target cell, a first message in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell. In some embodiments, the method 300 may further comprise at least one of: stopping the timer in response to receiving a second message responsive to the first message while the timer is running; determining that an L1/L2 inter-cell mobility procedure associated with the signaling is successful in response to receiving a second message responsive to the first message while the timer is running; restarting or resuming the RLM process based on at least the configuration associated with the target cell, only in response to receiving a second message responsive to the first message while the timer is running; and determining that an L1/L2 inter-cell mobility procedure associated with the signaling is failed in response to receiving no second message responsive to the first message until the timer is expired.

In some embodiments, the method 300 may further comprise at least one of: initiating an RRC Re-establishment procedure in response to detecting an RLF associated with an MCG; and initiating an SCG Failure Report procedure towards a network node operating as an MN for the UE in response to detecting an RLF associated with an SCG. In some embodiments, the configuration associated with the target cell may be at least one of: a configuration received in the signaling indicating L1/L2 intercell mobility execution to the target cell; and the second configuration.

In some embodiments, the one or more parameters may comprise at least one of: one or more reference signals to be measured; one or more RLF counters; and one or more RLF timers. In some embodiments, the signaling may be an L1/L2 signaling. In some embodiments, the signaling may comprise at least one of: DCI; and MAC CE.

Fig. 4 schematically shows an embodiment of an arrangement 400 which may be used in a UE (e.g., the UE 200) according to an embodiment of the present disclosure. Comprised in the arrangement 400 are a processing unit 406, e.g., with a Digital Signal Processor (DSP) or a Central Processing Unit (CPU). The processing unit 406 may be a single unit or a plurality of units to perform different actions of procedures described herein. The arrangement 400 may also comprise an input unit 402 for receiving signals from other entities, and an output unit 404 for providing signal(s) to other entities. The input unit 402 and the output unit 404 may be arranged as an integrated entity or as separate entities. Furthermore, the arrangement 400 may comprise at least one computer program product 408 in the form of a non-volatile or volatile memory, e.g., an Electrically Erasable Programmable Read-Only Memory (EEPROM), a flash memory and/or a hard drive. The computer program product 408 comprises a computer program 410, which comprises code/computer readable instructions, which when executed by the processing unit 406 in the arrangement 400 causes the arrangement 400 and/or the UE in which it is comprised to perform the actions, e.g., of the procedure described earlier in conjunction with Fig. 3 or any other variant.

The computer program 410 may be configured as a computer program code structured in computer program modules 410A and 410B. Hence, in an exemplifying embodiment when the arrangement 400 is used in a UE for RLM, the code in the computer program of the arrangement 400 includes: a module 410A configured to perform an RLM process based on at least one of a first configuration associated with a serving cell and at least one second configuration associated with at least one of the candidate cells; and a module 410B configured to continue the RLM process with or without an update of one or more parameters that are configured for the RLM process in response to receiving a signaling indicating L1/L2 inter-cell mobility execution to a target cell.

The computer program modules could essentially perform the actions of the flow illustrated in Fig. 3, to emulate the UE. In other words, when the different computer program modules are executed in the processing unit 406, they may correspond to different modules in the UE.

Although the code means in the embodiments disclosed above in conjunction with Fig. 4 are implemented as computer program modules which when executed in the processing unit causes the arrangement to perform the actions described above in conjunction with the figures mentioned above, at least one of the code means may in alternative embodiments be implemented at least partly as hardware circuits.

The processor may be a single CPU (Central processing unit), but could also comprise two or more processing units. For example, the processor may include general purpose microprocessors; instruction set processors and/or related chips sets and/or special purpose microprocessors such as Application Specific Integrated Circuit (ASICs). The processor may also comprise board memory for caching purposes. The computer program may be carried by a computer program product connected to the processor. The computer program product may comprise a computer readable medium on which the computer program is stored. For example, the computer program product may be a flash memory, a Random-access memory (RAM), a Read-Only Memory (ROM), or an EEPROM, and the computer program modules described above could in alternative embodiments be distributed on different computer program products in the form of memories within the UE.

Correspondingly to the method 300 as described above, an exemplary UE for RLM is provided. Fig. 5 is a block diagram of a UE 500 according to an embodiment of the present disclosure. The UE 500 may be, e.g., the UE 200 in some embodiments.

The UE 500 may be configured to perform the method 300 as described above in connection with Fig. 3. As shown in Fig. 5, the UE 500 may comprise: a performing module 510 configured to perform an RLM process based on at least one of a first configuration associated with a serving cell and at least one second configuration associated with at least one of the candidate cells; and a continuing module 520 configured to continue the RLM process with or without an update of one or more parameters that are configured for the RLM process in response to receiving a signaling indicating L1/L2 inter-cell mobility execution to a target cell.

The above modules 510 and 520 may be implemented as a pure hardware solution or as a combination of software and hardware, e.g., by one or more of: a processor or a micro-processor and adequate software and memory for storing of the software, a Programmable Logic Device (PLD) or other electronic component(s) or processing circuitry configured to perform the actions described above, and illustrated, e.g., in Fig. 3. Further, the UE 500 may comprise one or more further modules, each of which may perform any of the steps of the method 300 described with reference to Fig. 3.

Fig. 6 shows an example of a communication system QQ100 in accordance with some embodiments.

In the example, the communication system QQ100 includes a telecommunication network QQ102 that includes an access network QQ104, such as a radio access network (RAN), and a core network QQ106, which includes one or more core network nodes QQ108. The access network QQ104 includes one or more access network nodes, such as network nodes QQllOa and QQllOb (one or more of which may be generally referred to as network nodes QQ110), or any other similar 3^rd Generation Partnership Project (3GPP) access node or non-3GPP access point. The network nodes QQ110 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs QQ112a, QQ112b, QQ112c, and QQ112d (one or more of which may be generally referred to as UEs QQ112) to the core network QQ106 over one or more wireless connections.

Example wireless communications over a wireless connection include transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system QQ100 may include any number of wired or wireless networks, network nodes, UEs, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections. The communication system QQ100 may include and/or interface with any type of communication, telecommunication, data, cellular, radio network, and/or other similar type of system.

The UEs QQ112 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and/or operable to communicate wirelessly with the network nodes QQ110 and other communication devices. Similarly, the network nodes QQ110 are arranged, capable, configured, and/or operable to communicate directly or indirectly with the UEs QQ112 and/or with other network nodes or equipment in the telecommunication network QQ102 to enable and/or provide network access, such as wireless network access, and/or to perform other functions, such as administration in the telecommunication network QQ102.

In the depicted example, the core network QQ106 connects the network nodes QQ110 to one or more hosts, such as host QQ116. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network QQ106 includes one more core network nodes (e.g., core network node QQ108) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and/or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node QQ108. 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).

The host QQ116 may be under the ownership or control of a service provider other than an operator or provider of the access network QQ104 and/or the telecommunication network QQ102, and may be operated by the service provider or on behalf of the service provider. The host QQ116 may host a variety of applications to provide one or more service. Examples of such applications include live and prerecorded 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.

As a whole, the communication system QQ100 of Fig. 6 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and/or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and/or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

In some examples, the telecommunication network QQ102 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network QQ102 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network QQ102. For example, the telecommunications network QQ102 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.

In some examples, the UEs QQ112 are configured to transmit and/or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network QQ104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network QQ104. 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).

In the example, the hub QQ114 communicates with the access network QQ104 to facilitate indirect communication between one or more UEs (e.g., UE QQ112c and/or QQ112d) and network nodes (e.g., network node QQllOb). In some examples, the hub QQ114 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub QQ114 may be a broadband router enabling access to the core network QQ106 for the UEs. As another example, the hub QQ114 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 QQ110, or by executable code, script, process, or other instructions in the hub QQ114. As another example, the hub QQ114 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub QQ114 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub QQ114 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub QQ114 then provides to the UE either directly, after performing local processing, and/or after adding additional local content. In still another example, the hub QQ114 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.

The hub QQ114 may have a constant/persistent or intermittent connection to the network node QQllOb. The hub QQ114 may also allow for a different communication scheme and/or schedule between the hub QQ114 and UEs (e.g., UE QQ112c and/or QQ112d), and between the hub QQ114 and the core network QQ106. In other examples, the hub QQ114 is connected to the core network QQ106 and/or one or more UEs via a wired connection. Moreover, the hub QQ114 may be configured to connect to an M2M service provider over the access network QQ104 and/or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes QQ110 while still connected via the hub QQ114 via a wired or wireless connection. In some embodiments, the hub QQ114 may be a dedicated hub - that is, a hub whose primary function is to route communications to/from the UEs from/to the network node QQllOb. In other embodiments, the hub QQ114 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node QQllOb, but which is additionally capable of operating as a communication start and/or end point for certain data channels.

Fig. 7 shows a UE QQ200 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customerpremise equipment (CPE), vehicle-mounted or vehicle embedded/integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE.

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).

The UE QQ200 includes processing circuitry QQ202 that is operatively coupled via a bus QQ204 to an input/output interface QQ206, a power source QQ208, a memory QQ210, a communication interface QQ212, and/or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Fig. 7. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

The processing circuitry QQ202 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory QQ210. The processing circuitry QQ202 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry QQ202 may include multiple central processing units (CPUs).

In the example, the input/output interface QQ206 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and/or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE QQ200. 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.

In some embodiments, the power source QQ208 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source QQ208 may further include power circuitry for delivering power from the power source QQ208 itself, and/or an external power source, to the various parts of the UE QQ200 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source QQ208. Power circuitry may perform any formatting, converting, or other modification to the power from the power source QQ208 to make the power suitable for the respective components of the UE QQ200 to which power is supplied.

The memory QQ210 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory QQ210 includes one or more application programs QQ214, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data QQ216. The memory QQ210 may store, for use by the UE QQ200, any of a variety of various operating systems or combinations of operating systems.

The memory QQ210 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 inline memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and/or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as 'SIM card.' The memory QQ210 may allow the UE QQ200 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory QQ210, which may be or comprise a device-readable storage medium.

The processing circuitry QQ202 may be configured to communicate with an access network or other network using the communication interface QQ212. The communication interface QQ212 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna QQ222. The communication interface QQ212 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter QQ218 and/or a receiver QQ220 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter QQ218 and receiver QQ220 may be coupled to one or more antennas (e.g., antenna QQ222) and may share circuit components, software or firmware, or alternatively be implemented separately.

In the illustrated embodiment, communication functions of the communication interface QQ212 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, locationbased communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and/or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol/internet protocol (TCP/IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface QQ212, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

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.

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. Nonlimiting 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 the UE QQ200 shown in Fig. 7.

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

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.

Fig. 8 shows a network node QQ300 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and/or operable to communicate directly or indirectly with a UE and/or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)).

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).

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

The network node QQ300 includes a processing circuitry QQ302, a memory QQ304, a communication interface QQ306, and a power source QQ308. The network node QQ300 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node QQ300 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node QQ300 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory QQ304 for different RATs) and some components may be reused (e.g., a same antenna QQ310 may be shared by different RATs). The network node QQ300 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node QQ300, 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 QQ300.

The processing circuitry QQ302 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 QQ300 components, such as the memory QQ304, to provide network node QQ300 functionality.

In some embodiments, the processing circuitry QQ302 includes a system on a chip (SOC). In some embodiments, the processing circuitry QQ302 includes one or more of radio frequency (RF) transceiver circuitry QQ312 and baseband processing circuitry QQ314. In some embodiments, the radio frequency (RF) transceiver circuitry QQ312 and the baseband processing circuitry QQ314 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 QQ312 and baseband processing circuitry QQ314 may be on the same chip or set of chips, boards, or units.

The memory QQ304 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device- readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by the processing circuitry QQ302. The memory QQ304 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and/or other instructions capable of being executed by the processing circuitry QQ302 and utilized by the network node QQ300. The memory QQ304 may be used to store any calculations made by the processing circuitry QQ302 and/or any data received via the communication interface QQ306. In some embodiments, the processing circuitry QQ302 and memory QQ304 is integrated.

The communication interface QQ306 is used in wired or wireless communication of signaling and/or data between a network node, access network, and/or UE. As illustrated, the communication interface QQ306 comprises port(s)/terminal(s) QQ316 to send and receive data, for example to and from a network over a wired connection. The communication interface QQ306 also includes radio front-end circuitry QQ318 that may be coupled to, or in certain embodiments a part of, the antenna QQ310. Radio front-end circuitry QQ318 comprises filters QQ320 and amplifiers QQ322. The radio front-end circuitry QQ318 may be connected to an antenna QQ310 and processing circuitry QQ302. The radio front-end circuitry may be configured to condition signals communicated between antenna QQ310 and processing circuitry QQ302. The radio front-end circuitry QQ318 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry QQ318 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters QQ320 and/or amplifiers QQ322. The radio signal may then be transmitted via the antenna QQ310. Similarly, when receiving data, the antenna QQ310 may collect radio signals which are then converted into digital data by the radio front-end circuitry QQ318. The digital data may be passed to the processing circuitry QQ302. In other embodiments, the communication interface may comprise different components and/or different combinations of components.

In certain alternative embodiments, the network node QQ300 does not include separate radio front-end circuitry QQ318, instead, the processing circuitry QQ302 includes radio front-end circuitry and is connected to the antenna QQ310. Similarly, in some embodiments, all or some of the RF transceiver circuitry QQ312 is part of the communication interface QQ306. In still other embodiments, the communication interface QQ306 includes one or more ports or terminals QQ316, the radio front-end circuitry QQ318, and the RF transceiver circuitry QQ312, as part of a radio unit (not shown), and the communication interface QQ306 communicates with the baseband processing circuitry QQ314, which is part of a digital unit (not shown).

The antenna QQ310 may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals. The antenna QQ310 may be coupled to the radio front-end circuitry QQ318 and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In certain embodiments, the antenna QQ310 is separate from the network node QQ300 and connectable to the network node QQ300 through an interface or port.

The antenna QQ310, communication interface QQ306, and/or the processing circuitry QQ302 may be configured to perform any receiving operations and/or certain obtaining operations described herein as being performed by the network node. Any information, data and/or signals may be received from a UE, another network node and/or any other network equipment. Similarly, the antenna QQ310, the communication interface QQ306, and/or the processing circuitry QQ302 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.

The power source QQ308 provides power to the various components of network node QQ300 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source QQ308 may further comprise, or be coupled to, power management circuitry to supply the components of the network node QQ300 with power for performing the functionality described herein. For example, the network node QQ300 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source QQ308. As a further example, the power source QQ308 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.

Embodiments of the network node QQ300 may include additional components beyond those shown in Fig. 8 for providing certain aspects of the network node's functionality, including any of the functionality described herein and/or any functionality necessary to support the subject matter described herein. For example, the network node QQ300 may include user interface equipment to allow input of information into the network node QQ300 and to allow output of information from the network node QQ300. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node QQ300.

Fig. 9 is a block diagram of a host QQ400, which may be an embodiment of the host QQ116 of Fig. 6, in accordance with various aspects described herein. As used herein, the host QQ400 may be or comprise various combinations hardware and/or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host QQ400 may provide one or more services to one or more UEs.

The host QQ400 includes processing circuitry QQ402 that is operatively coupled via a bus QQ404 to an input/output interface QQ406, a network interface QQ408, a power source QQ410, and a memory QQ412. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Fig. 7 and Fig. 8, such that the descriptions thereof are generally applicable to the corresponding components of host QQ400.

The memory QQ412 may include one or more computer programs including one or more host application programs QQ414 and data QQ416, which may include user data, e.g., data generated by a UE for the host QQ400 or data generated by the host QQ400 for a UE. Embodiments of the host QQ400 may utilize only a subset or all of the components shown. The host application programs QQ414 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (WC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FI_AC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems). The host application programs QQ414 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host QQ400 may select and/or indicate a different host for over-the-top services for a UE. The host application programs QQ414 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.

Fig. 10 is a block diagram illustrating a virtualization environment QQ500 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 QQ500 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.

Applications QQ502 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment QQ500 to implement some of the features, functions, and/or benefits of some of the embodiments disclosed herein. Hardware QQ504 includes processing circuitry, memory that stores software and/or instructions executable by hardware processing circuitry, and/or other hardware devices as described herein, such as a network interface, input/output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers QQ506 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs QQ508a and QQ508b (one or more of which may be generally referred to as VMs QQ508), and/or perform any of the functions, features and/or benefits described in relation with some embodiments described herein. The virtualization layer QQ506 may present a virtual operating platform that appears like networking hardware to the VMs QQ508.

The VMs QQ508 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer QQ506. Different embodiments of the instance of a virtual appliance QQ502 may be implemented on one or more of VMs QQ508, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

In the context of NFV, a VM QQ508 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, nonvirtualized machine. Each of the VMs QQ508, and that part of hardware QQ504 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 QQ508 on top of the hardware QQ504 and corresponds to the application QQ502.

Hardware QQ504 may be implemented in a standalone network node with generic or specific components. Hardware QQ504 may implement some functions via virtualization. Alternatively, hardware QQ504 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 QQ510, which, among others, oversees lifecycle management of applications QQ502. In some embodiments, hardware QQ504 is coupled to one or more radio units that each includes one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system QQ512 which may alternatively be used for communication between hardware nodes and radio units.

Fig. 11 shows a communication diagram of a host QQ602 communicating via a network node QQ604 with a UE QQ606 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as a UE QQ112a of Fig. 6 and/or UE QQ200 of Fig. 7), network node (such as network node QQllOa of Fig. 6 and/or network node QQ300 of Fig. 8), and host (such as host QQ116 of Fig. 6 and/or host QQ400 of Fig. 9) discussed in the preceding paragraphs will now be described with reference to Fig. 11.

Like host QQ400, embodiments of host QQ602 include hardware, such as a communication interface, processing circuitry, and memory. The host QQ602 also includes software, which is stored in or accessible by the host QQ602 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE QQ606 connecting via an over- the-top (OTT) connection QQ650 extending between the UE QQ606 and host QQ602. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection QQ650.

The network node QQ604 includes hardware enabling it to communicate with the host QQ602 and UE QQ606. The connection QQ660 may be direct or pass through a core network (like core network QQ106 of Fig. 6) and/or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.

The UE QQ606 includes hardware and software, which is stored in or accessible by UE QQ606 and executable by the UE's processing circuitry. The software includes a client application, such as a web browser or operator-specific "app" that may be operable to provide a service to a human or non-human user via UE QQ606 with the support of the host QQ602. In the host QQ602, an executing host application may communicate with the executing client application via the OTT connection QQ650 terminating at the UE QQ606 and host QQ602. In providing the service to the user, the UE's client application may receive request data from the host's host application and provide user data in response to the request data. The OTT connection QQ650 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through the OTT connection QQ650.

The OTT connection QQ650 may extend via a connection QQ660 between the host QQ602 and the network node QQ604 and via a wireless connection QQ670 between the network node QQ604 and the UE QQ606 to provide the connection between the host QQ602 and the UE QQ606. The connection QQ660 and wireless connection QQ670, over which the OTT connection QQ650 may be provided, have been drawn abstractly to illustrate the communication between the host QQ602 and the UE QQ606 via the network node QQ604, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

As an example of transmitting data via the OTT connection QQ650, in step QQ608, the host QQ602 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE QQ606. In other embodiments, the user data is associated with a UE QQ606 that shares data with the host QQ602 without explicit human interaction. In step QQ610, the host QQ602 initiates a transmission carrying the user data towards the UE QQ606. The host QQ602 may initiate the transmission responsive to a request transmitted by the UE QQ606. The request may be caused by human interaction with the UE QQ606 or by operation of the client application executing on the UE QQ606. The transmission may pass via the network node QQ604, in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step QQ612, the network node QQ604 transmits to the UE QQ606 the user data that was carried in the transmission that the host QQ602 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step QQ614, the UE QQ606 receives the user data carried in the transmission, which may be performed by a client application executed on the UE QQ606 associated with the host application executed by the host QQ602. In some examples, the UE QQ606 executes a client application which provides user data to the host QQ602. The user data may be provided in reaction or response to the data received from the host QQ602. Accordingly, in step QQ616, the UE QQ606 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input/output interface of the UE QQ606. Regardless of the specific manner in which the user data was provided, the UE QQ606 initiates, in step QQ618, transmission of the user data towards the host QQ602 via the network node QQ604. In step QQ620, in accordance with the teachings of the embodiments described throughout this disclosure, the network node QQ604 receives user data from the UE QQ606 and initiates transmission of the received user data towards the host QQ602. In step QQ622, the host QQ602 receives the user data carried in the transmission initiated by the UE QQ606.

One or more of the various embodiments improve the performance of OTT services provided to the UE QQ606 using the OTT connection QQ650, in which the wireless connection QQ670 forms the last segment. More precisely, the teachings of these embodiments may improve the data rate, latency, power consumption and thereby provide benefits such as reduced user waiting time, relaxed restriction on file size, improved content resolution, better responsiveness, extended battery lifetime.

In an example scenario, factory status information may be collected and analyzed by the host QQ602. As another example, the host QQ602 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host QQ602 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host QQ602 may store surveillance video uploaded by a UE. As another example, the host QQ602 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs. As other examples, the host QQ602 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing and/or transmitting data.

In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection QQ650 between the host QQ602 and UE QQ606, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of the host QQ602 and/or UE QQ606. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection QQ650 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of the OTT connection QQ650 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of the network node QQ604. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency and the like, by the host QQ602. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or 'dummy' messages, using the OTT connection QQ650 while monitoring propagation times, errors, etc.

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

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

The present disclosure is described above with reference to the embodiments thereof. However, those embodiments are provided just for illustrative purpose, rather than limiting the present disclosure. The scope of the disclosure is defined by the attached claims as well as equivalents thereof. Those skilled in the art can make various alternations and modifications without departing from the scope of the disclosure, which all fall into the scope of the disclosure.

Abbreviation Explanation

5GC or 5GCN 5G Core Network

ACK Acknowledgement

AGC Automatic Gain Control

AMF Access and Mobility Management Function

AP Application Protocol

ARQ Automatic Repeat Request

BSR Buffer Status Report BWP Bandwidth Part

CA Carrier Aggregation

CE Control Element

CGI Cell Global Identity

CHO Conditional Handover

CN Core Network

CP Control Plane

CPA Conditional PSCell Addition

CPC Conditional PSCell Change

CQI Channel Quality Indicator

C-RNTI Cell Radio Network Temporary Identifier

CSI Channel State Information

CU Central Unit

DAPS Dual Active Protocol Stack

DC Dual Connectivity

DCI Downlink Control Information

DL Downlink

DRB Data Radio Bearer

DU Distributed Unit eNB (EUTRAN) base station

E-RAB EUTRAN Radio Access Bearer

E-UTRA Evolved Universal Terrestrial Radio Access

E-UTRAN Evolved Universal Terrestrial Radio Access Network

FDD Frequency Division Duplex gNB NR base station

GTP-U GPRS Tunneling Protocol - User Plane

HARQ Hybrid ARQ

IE Information Element

IP Internet Protocol

LTE Long Term Evolution

MAC Medium Access Control

MAC CE MAC Control Element

MCG Master Cell Group MeNB Master eNB

MgNB Master gNB

MN Master Node

MR-DC Multi-Radio Dual Connectivity

NACK Negative Acknowledgement

NAS Non Access Stratum

Ng-eNB Next Generation Evolved Node B

NG-RAN Next Generation Radio Access Network

NR New Radio

PCell Primary Cell

PCI Physical Cell Identity

PDCCH Physical Downlink Control Channel

PDCP Packet Data Convergence Protocol

PHR Power Headroom Report

PSCell Primary Secondary Cell (in LTE) or

Primary SCG Cell (in NR)

PUCCH Physical Uplink Control Channel

PUSCH Physical Uplink Shared Channel

RACH Random Access Channel

RAT Radio Access Technology

RB Radio Bearer

RLC Radio Link Control

RLF Radio Link Failure

RRC Radio Resource Control

SCell Secondary Cell

SCG Secondary Cell Group

SCTP Stream Control Transmission Protocol

SeNB Secondary eNB

SgNB Secondary gNB

SINR Signal to Interference plus Noise Ratio

SN Secondary Node

SpCell Special Cell, the primary cell of a master or secondary cell group SR Scheduling Request

SRB Signaling Radio Bearer

SSB Synchronization Signal Block

S-SN Source Secondary Node

SUL Supplementary Uplink

TAT Time Alignment Timer

TCI Transmission Configuration Indication

TDD Time Division Duplex

TEID Tunnel Endpoint IDentifier

TNL Transport Network Layer

T-SN Target Secondary Node

UCI Uplink Control Information

UDP User Datagram Protocol

UE User Equipment

UL Uplink

UL-SCH Uplink Shared Channel

UP User Plane

UPF User Plane Function

URLLC Ultra Reliable Low Latency Communication

X2 Interface between base stations

Claims

Claims What is claimed is:

1. A method (300) at a User Equipment (UE) (200) for Radio Link Monitoring (RLM), the UE (200) being configured with one or more candidate cells for Layer 1 (LI) and/or Layer 2 (L2) (L1/L2) inter-cell mobility, the method (300) comprising: performing (S310) an RLM process based on at least one of a first configuration associated with a serving cell and at least one second configuration associated with at least one of the candidate cells; and continuing (S320) the RLM process with or without an update of one or more parameters that are configured for the RLM process in response to receiving a signaling indicating L1/L2 inter-cell mobility execution to a target cell.

2. The method (300) of claim 1, wherein the continuing the RLM process with an update of one or more parameters that are configured for the RLM process comprises: updating the one or more parameters based on at least a configuration associated with the target cell in response to the RLM process being performed based not on the second configuration; and continuing the RLM process with the updated parameters.

3. The method (300) of claim 2, wherein the performing the RLM process based on at least one of the first configuration and the second configuration comprises: performing the RLM process by monitoring a first set of RLM Reference Signals

(RLM-RSs) of the serving cell, wherein the updating the one or more parameters based on at least the configuration associated with the target cell comprises: updating the first set of RLM-RSs of the serving cell with a second set of RLM-RSs indicated by the configuration associated with the target cell, wherein the continuing the RLM process with the updated parameters comprises: continuing the RLM process by monitoring the second set of RLM-RSs.

4. The method (300) of claim 3, wherein the first set of RLM-RSs comprise at least one of: - one or more reference signals associated with one or more beams that are being used for transmission of one or more control and/or data channels in the serving cell;

- one or more Synchronous Signal (SS) and Physical Broadcast Channel (PBCH) blocks (SSBs) configured as Quasi Co-Location (QCL) source of one or more currently activated Transmission Configuration Indicator (TCI) states of the serving cell;

- one or more Channel State Information Reference Signals (CSI-RSs) configured as QCL source of one or more currently activated TCI states of the serving cell;

- one or more reference signals associated with one or more beams indicated by the first configuration;

- one or more SSBs indicated by the first configuration; and

- one or more CSI-RSs indicated by the first configuration.

5. The method (300) of claim 3 or 4, wherein the second set of RLM-RSs comprise at least one of:

- one or more reference signals associated with one or more beams that are being activated for transmission of one or more control and/or data channels in the target cell;

- one or more SSBs configured as QCL source of one or more TCI states of the target cell that are being activated;

- one or more CSI-RSs configured as QCL source of one or more TCI states of the target cell that are being activated;

- one or more reference signals associated with one or more beams indicated by the configuration associated with the target cell;

- one or more SSBs indicated by the configuration associated with the target cell; and

- one or more CSI-RSs indicated by the configuration associated with the target cell.

6. The method (300) of any of claims 3 to 5, further comprising: generating an Out Of Sync (OOS) indication in response to determining that measurements on all RLM-RSs in the first set are worse than a configured threshold.

7. The method (300) of any of claims 1 to 6, wherein the continuing the RLM process without an update of one or more parameters that are configured for the RLM process comprises: continuing the RLM process by continuing to use the one or more parameters in response to the RLM process being performed based on the first configuration and the second configuration.

8. The method (300) of claim 7, wherein the performing the RLM process based on at least one of the first configuration and the second configuration comprises: performing the RLM process by monitoring a single set of RLM-RSs that comprise at least one RLM-RS of the serving cell and at least one RLM-RS of a candidate cell the UE (200) is configured with, wherein the continuing the RLM process by continuing to use the one or more parameters comprises: continuing the RLM process by continuing to monitor the single set of RLM-RSs.

9. The method (300) of claim 8, wherein the single set of RLM-RSs comprise at least one of:

- one or more RLM-RSs configured for a current active Bandwidth Part (BWP) of the serving cell;

- one or more reference signals associated with one or more beams configured as QCL source of an activated TCI state of the serving cell;

- one or more SSBs configured as QCL source of an activated TCI state of the serving cell;

- one or more CSI-RSs configured as QCL source of an activated TCI state of the serving cell;

- one or more RLM-RSs configured for a BWP of the configuration associated with the target cell;

- one or more reference signals configured as QCL source of one or more TCI states of the configuration associated with the target cell;

- one or more reference signals associated with at least one beam of all candidate cells; and - one or more reference signals associated with at least one beam of one or more candidate cells that are explicitly indicated in a configuration.

10. The method (300) of claim 8 or 9, further comprising: receiving, from the target cell, a configuration indicating one or more SSBs and/or CSI-RS resources to be monitored; and reconfiguring the single set of RLM-RSs based on at least the received configuration.

11. The method (300) of any of claims 8 to 10, further comprising at least one: activating one or more RLM-RSs in the single set; and deactivating one or more RLM-RSs in the single set.

12. The method (300) of claim 11, wherein the activating one or more RLM-RSs in the single set comprises: activating one or more RLM-RSs in the single set that are associated with the target cell in response to the execution of the L1/L2 inter-cell mobility to the target cell.

13. The method (300) of claim 11 or 12, wherein the deactivating one or more RLM- RSs in the single set comprises: deactivating one or more RLM-RSs in the single set that are associated with the serving cell before the execution of the L1/L2 inter-cell mobility to the target cell.

14. The method (300) of any of claims 8 to 13, further comprising at least one of: determining the at least one RLM-RS in the single set that is associated with the candidate cell as at least one RLM-RS of the serving cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell; and determining the at least one RLM-RS in the single set that is associated with the serving cell as at least one RLM-RS of the candidate cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

15. The method (300) of any of claims 8 to 14, further comprising: determining the at least one RLM-RS in the single set that is associated with the candidate cell as at least one RLM-RS of the serving cell and also at least one RLM-RS of a candidate cell that is different from the serving cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

16. The method (300) of any of claims 8 to 15, further comprising: generating an OOS indication in response to determining that measurements on all RLM-RSs in the single set are worse than a configured threshold.

17. The method (300) of any of claims 8 to 16, wherein the continuing to monitor the single set of RLM-RSs is performed only in response to determining that the single set of RLM-RSs comprise at least one RLM-RS of the target cell.

18. The method (300) of any of claims 1 to 17, further comprising: stopping an RLF timer associated with the RLM process in response to:

- determining that the RLF timer is running; and

- receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

19. The method (300) of claim 18, further comprising: starting another RLF timer with a value indicated in the configuration associated with the target cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

20. The method (300) of any of claims 1 to 19, further comprising: continuing to use an RLF timer associated with the RLM process in response to:

- determining that the RLF timer is running; and

21. The method (300) of claim 20, further comprising: stopping the RLF timer in response to:

- determining that the RLF timer is running; and - receiving at least a configured number of consecutive In-Sync (IS) indications from a lower layer of the UE (200) for the target cell.

22. The method (300) of claim 20 or 21, further comprising: resetting an RLF counter associated with the RLF timer while continuing to use the RLF timer in response to:

- determining that the RLF timer is running; and

23. The method (300) of claim 20, further comprising: stopping the RLF timer in response to:

- determining that the RLF timer is running; and

- receiving at least a configured number of consecutive IS indications from a lower layer of the UE (200) for the serving cell and the target cell.

24. The method (300) of claim 20 or 23, further comprising: continuing to use the RLF timer without resetting an RLF counter associated with the RLF timer in response to:

- determining that the RLF timer is running; and

25. The method (300) of any of claims 1 to 24, further comprising: resetting an RLF counter associated with the RLM process in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

26. The method (300) of claim 25, wherein the resetting the RLF counter comprises: resetting the value of the RLF counter to a corresponding value indicated by the configuration associated with the target cell.

27. The method (300) of any of claims 1 to 24, further comprising: continuing to use an RLF counter associated with the RLM process in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

28. The method (300) of claim 27, further comprising: stopping an RLF timer associated with the RLF counter, only in response to:

- determining that the RLF timer is running; and

- receiving at least a configured number of consecutive IS indications from a lower layer of the UE (200) for the target cell.

29. The method (300) of any of claims 18 to 28, wherein the RLF counter is the N310 counter or the N311 counter, wherein the RLF timer is the T310 timer.

30. The method (300) of any of claims 1 to 29, further comprising at least one of: stopping or suspending the RLM process in the serving cell in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell; starting a timer in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell; and transmitting, to a network node associated with the target cell, a first message in response to receiving the signaling indicating L1/L2 inter-cell mobility execution to the target cell.

31. The method (300) of claim 30, further comprising at least one of: stopping the timer in response to receiving a second message responsive to the first message while the timer is running; determining that an L1/L2 inter-cell mobility procedure associated with the signaling is successful in response to receiving a second message responsive to the first message while the timer is running; restarting or resuming the RLM process based on at least the configuration associated with the target cell, only in response to receiving a second message responsive to the first message while the timer is running; and determining that an L1/L2 inter-cell mobility procedure associated with the signaling is failed in response to receiving no second message responsive to the first message until the timer is expired.

32. The method (300) of any of claims 1 to 31, further comprising at least one of: initiating a Radio Resource Control (RRC) Re-establishment procedure in response to detecting an RLF associated with a Master Cell Group (MCG); and initiating a Secondary Cell Group (SCG) Failure Report procedure towards a network node operating as a Master Node (MN) for the UE (200) in response to detecting an RLF associated with an SCG.

33. The method (300) of any of claims 2 to 32, wherein the configuration associated with the target cell is at least one of:

- a configuration received in the signaling indicating L1/L2 inter-cell mobility execution to the target cell; and

- the second configuration.

34. The method (300) of any of claims 1 to 33, wherein the one or more parameters comprise at least one of:

- one or more reference signals to be measured;

- one or more Radio Link Failure (RLF) counters; and

- one or more RLF timers.

35. The method (300) of any of claims 1 to 34, wherein the signaling is an L1/L2 signaling.

36. The method (300) of any of claims 1 to 35, wherein the signaling comprises at least one of:

- Downlink Control Information (DCI); and

- Medium Access Control (MAC) Control Element (CE).

37. A UE (200, 400, 500) configured with one or more candidate cells for L1/L2 intercell mobility, the UE (200, 400, 500) comprising: a processor (406); a memory (408) storing instructions which, when executed by the processor (406), cause the UE (200, 400, 500) to: perform an RLM process based on at least one of a first configuration associated with a serving cell and at least one second configuration associated with at least one of the candidate cells; and continue the RLM process with or without an update of one or more parameters that are configured for the RLM process in response to receiving a signaling indicating L1/L2 inter-cell mobility execution to a target cell.

38. The UE (200, 400, 500) of claim 37, wherein the instructions, when executed by the processor (406), further cause the UE (200, 400, 500) to perform the method (300) of any of claims 2 to 36.

39. A computer program (410) comprising instructions which, when executed by at least one processor (406), cause the at least one processor (406) to carry out the method (300) of any of claims 1 to 36.

40. A carrier (408) containing the computer program of claim 39, wherein the carrier (408) is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

41. A telecommunication system (20), comprising: at least one UE (200) configured with one or more candidate cells (202, 203, 204) for L1/L2 inter-cell mobility, the UE (200) comprising: a processor; a memory storing instructions which, when executed by the processor, cause the UE (200) to: perform an RLM process based on at least one of a first configuration associated with a serving cell (201) and at least one second configuration associated with at least one of the candidate cells (202, 203, 204); and continue the RLM process with or without an update of one or more parameters that are configured for the RLM process in response to receiving a signaling indicating L1/L2 inter-cell mobility execution to a target cell (20x).

42. The telecommunication system (20) of claim 41, wherein the instructions stored in the memory of the corresponding UE (200), when executed by the processor of the corresponding UE (200), further cause the corresponding UE (200) to perform the method (300) of any of claims 2 to 36.