Methods and systems for configuring and performing LTM cell switch

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Embodiments herein disclose methods and systems for handling current common and dedicated configurations related to a Secondary Cell Group (SCG) with respect to execution of a Lower-Layered Triggered Mobility (LTM) cell switch triggered on a Master Cell Group (MCG) (MCG LTM Cell Switch). Embodiments herein disclose methods and systems for handling current common and dedicated configurations related to an MCG with respect to execution of a Lower-Layered Triggered Mobility (LTM) cell switch triggered on a SCG (SCG LTM Cell Switch). Embodiments herein disclose methods and systems for handling Signaling Radio Bearer4 (SRB4) or Signaling Radio Bearer (SRB) for reporting Artificial Intelligence / Machine Learning (AI / ML) related data during the LTM cell switch.

Description

METHODS AND SYSTEMS FOR CONFIGURING AND PERFORMING LTM CELL SWITCH

[0001] Embodiments disclosed herein relate to wireless communication networks, and more particularly to managing a Lower-Layered Triggered Mobility (LTM) Cell Switch in a wireless communication network.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] The 3rd Generation Partnership Project (3GPP) release 18 introduced Lower Layers (L1 / L2 layers) Triggered Mobility (LTM) to solve problems related to associated with layer 3 (L3) mobility; for example, latency, signalling overhead, and so on. As per 3GPP, the goal of LTM is to enable a serving cell change via L1 / L2 signalling, in order to reduce the latency, overhead and interruption time. The Network (gNodeB (gNB)) may configure a User Equipment (UE) with multiple candidate cells to allow fast application of configurations for candidate cells. The UE may be configured with a complete configuration for one or more LTM candidate cells. The UE also may be configured with a LTM reference configuration, and an LTM candidate cell configuration.

[0009] The Network may further send a MAC CE to dynamically switch the UE from a source cell to one of the configured candidate cells. Further, LTM can be triggered based on L1 measurements rather than L3 measurements. The Network also may configure the UE to perform LTM upon a Master Cell Group (MCG) failure. The 3GPP proposes to perform LTM without a reset of lower layers to avoid data loss and to reduce the additional delay of data recovery wherever it is possible.

[0010] Embodiments of the present disclosure is to provide an apparatus and method for effectively providing a service in a wireless communication system.

[0011] The principal object of embodiments herein is to disclose methods and systems for handling current common and dedicated configurations related to a Secondary Cell Group (SCG) with respect to execution of a Lower-Layered Triggered Mobility (LTM) cell switch triggered on a Master Cell Group (MCG) (MCG LTM Cell Switch).

[0012] Another object of embodiments herein is to disclose methods and systems for handling current common and dedicated configurations related to an MCG with respect to execution of a Lower-Layered Triggered Mobility (LTM) cell switch triggered on a SCG (SCG LTM Cell Switch).

[0013] Another object of embodiments herein is to disclose methods and systems for handling Signaling Radio Bearer4 (SRB4) or Signaling Radio Bearer (SRB) for reporting Artificial Intelligence / Machine Learning (AI / ML) related data during the LTM cell switch.

[0014] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating at least one embodiment and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

[0015] Embodiments of the present disclosure is to provide an apparatus and method for effectively providing a service in a wireless communication system.

[0016] Embodiments herein are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the following illustratory drawings. Embodiments herein are illustrated by way of examples in the accompanying drawings, and in which:

[0017] FIG. 1 is a block diagram of a terminal or user equipment (UE), according to embodiments as disclosed herein;

[0018] FIG. 2 depicts a process for performing MCG LTM cell switch execution, according to embodiments as disclosed herein;

[0019] FIG. 3 depicts a process for performing MCG LTM cell switch execution, according to embodiments as disclosed herein;

[0020] FIG. 4 depicts a process for applying default SRB during LTM cell switch, according to embodiments as disclosed herein;

[0021] FIG. 5 depicts a process for applying default SRB during LTM cell switch, according to embodiments as disclosed herein;

[0022] FIG. 6 depicts a method for Lower-layer Triggered Mobility (LTM) cell switch execution in a wireless network, according to embodiments as disclosed herein;

[0023] FIG. 7 is a block diagram of a Master Node (MN), according to embodiments as disclosed herein; and

[0024] FIG. 8 depicts a method for Lower-layer Triggered Mobility (LTM) cell switch execution in a wireless network, according to embodiments as disclosed herein.

[0025] 3GPP proposes to perform LTM, without reset of lower layers (such as, Medium Access Control　(MAC)　) to avoid data loss and to reduce the additional delay of data recovery (wherever possible).

[0026] LTM is a procedure in which a gNB receives L1 measurement report(s) from a UE, and on the basis of the L1 measurement report(s), the gNB changes the UE's serving cell by a cell switch command signaled via a MAC Control Element (CE). LTM based on L3 measurements also is supported. The cell switch command indicates an LTM candidate cell configuration that the gNB had previously prepared and provided to the UE through Radio Resource Control (RRC) signalling. Then, the UE switches to the target cell according to the cell switch command. The LTM procedure can be used to reduce the mobility latency, as described.

[0027] The Network may request the UE to perform early Timing Advance (TA) acquisition of a candidate cell before a cell switch. The network indicates whether the UE shall access the target cell with a Random Access (RA) procedure if a TA value is not provided or with a Physical Uplink Shared Channel (PUSCH) transmission using the indicated TA value in the cell switch command. For RACH-less LTM, the UE either monitors Physical Downlink Control Channel (PDCCH) for dynamic scheduling from the target cell upon LTM cell switch, or the UE selects the configured grant occasion associated with the beam indicated in the cell switch command.

[0028] The following principles apply to R18 LTM:

[0029] - The UE does not update its security key in LTM; and

[0030] - Subsequent LTM is supported.

[0031] LTM supports both intra-gNB- Distributed Unit (DU) and intra-gNB- Central Unit (CU) inter-gNB-DU mobility. LTM also supports inter-frequency mobility, including mobility to inter-frequency cell that is not a current serving cell. The following scenarios are supported:

[0032] - Primary Cell (PCell) change in a non-Carrier Aggregation (CA) (non-CA) scenario;

[0033] - PCell change in a CA scenario; and

[0034] - Dual connectivity scenario, at least for the Primary Secondary Cell (PSCell) change without Master Node (MN) involvement case; i.e., intra-Secondary Node (SN) (intra-SN) PSCell change.

[0035] A configuration including a flag (for example, ltm-ConfigComplete) can be considered to be a complete configuration. The UE can directly apply it. If the configuration does not contain the flag (for example, ltm-ConfigComplete), the UE may apply the received LTM candidate configuration using an LTM reference configuration. The UE may first generate a complete configuration using LTM candidate configuration and the LTM reference configuration. The UE can then apply the generated complete configuration.

[0036] A cell switch command is conveyed in a MAC CE, which contains the necessary information to perform the LTM cell switch. The UE also may perform cell switch after certain failures.

[0037] 5.3.5.18.6 LTM cell switch execution:

[0038] Upon the indication by lower layers that an LTM cell switch procedure is triggered, or upon performing LTM cell switch following cell selection performed while timer T311 was running, as specified in 5.3.7.3, the UE shall:

[0039] 1> if the LTM cell switch is triggered on the MCG:

[0040] 2> release / clear all current dedicated and common radio configurations which have neither been received via SRB1 withinmrdc-SecondaryCellGroup, nor via SRB3 except for the following:

[0041] - the radio bearer configuration (configured viaRadioBearerConfig)

[0042] - thelogicalChannelIdentityandlogicalChannelIdentityExtof RLC bearers configured inRLC-BearerConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322;

[0043] - thebh-LogicalChannelIdentityof BH RLC channels configured inBH-RLC-ChannelConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0044] - the UE variablesVarLTM-ServingCellNoResetIDandVarLTM-ServingCellUE-MeasuredTA-ID;

[0045] - theltm-Config;

[0046] - the MCG C-RNTI;

[0047] - the AS security configurations associated with the master key;

[0048] - the logged measurement configuration;

[0049] 1> else, if the LTM cell switch is triggered on the SCG:

[0050] 2> release / clear all current dedicated and common radio configurations which have been received either via SRB1 withinmrdc-SecondaryCellGroup, or via SRB3 except for the following:

[0051] - the radio bearer configuration (configured viaRadioBearerConfigIE)

[0052] - thelogicalChannelIdentityandlogicalChannelIdentityExtof RLC bearers configured inRLC-BearerConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0053] - thebh-LogicalChannelIdentityof BH RLC channels configured inBH-RLC-ChannelConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0054] - the UE variablesVarLTM-ServingCellNoResetIDandVarLTM-ServingCellUE-MeasuredTA-ID;

[0055] - theltm-Config;

[0056] - the AS security configurations associated with the secondary key;

[0057] 1> for each SRB / DRB in the current UE configuration:

[0058] 2> if the LTM cell switch is triggered on the MCG and the SRB / DRB using the master key; or

[0059] 2> if the LTM cell switch is triggered on the SCG and the SRB / DRB using the secondary key:

[0060] 3> keep the associated PDCP and SDAP entities, their state variables, buffers and timers;

[0061] 3> release all fields related to the SRB / DRB configuration except forsrb-Identityanddrb-Identity;

[0062] 1> apply the default L1 parameter values as specified in corresponding physical layer specifications except for the parameters for which values are provided in SIB1;

[0063] 1> use the default values specified in 9.2.3 for timers T310, T311 and constants N310, N311 associated with the cell group for which the LTM cell switch procedure is triggered, where T310, N310, and N311 are for both MCG and SCG, and T311 is only for the MCG;

[0064] 1> apply the default MAC Cell Group configuration as specified in 9.2.2 for the cell group for which the LTM cell switch procedure is triggered;

[0065] 1> for eachsrb-Identityin the current UE configuration:

[0066] 2> apply the default SRB configuration defined in 9.2.1 for the corresponding SRB;

[0067] 1> if theLTM-CandidateIE inltm-Configindicated by lower layers or for the selected cell in accordance with 5.3.7.3 does not contain the fieldltm-NoResetIDand if the UE does not have any value stored ofltm-ServingCellNoResetIDwithinVarLTM-ServingCellNoResetID; or

[0068] 1> if the value of fieldltm-NoResetIDcontained within theLTM-CandidateIE inltm-Configindicated by lower layers or for the selected cell in accordance with 5.3.7.3 is not equal to the value ofltm-ServingCellNoResetIDwithinVarLTM-ServingCellNoResetID:

[0069] 2> for eachlogicalChannelIdentityandlogicalChannelIdentityExtthat is part of the current UE configuration for the cell group for which the LTM cell switch procedure is triggered:

[0070] 3> ifservedRadioBeareris set todrb-Identity:

[0071] 4> after the end of this procedure, re-establish the corresponding RLC entity as specified in TS 38.322 [4], after applying the LTM configuration inltm-CandidateConfigwithin theLTM-Candidate IEinltm-Config;

[0072] 2> for eachbh-LogicalChannelIdentitythat is part of the current UE configuration for the cell group for which the LTM cell switch procedure is triggered:

[0073] 3> after the end of this procedure, re-establish the corresponding RLC entity as specified in TS 38.322 [4], after applying the LTM configuration inltm-CandidateConfigwithin the LTM-Candidate IE inltm-Config;

[0074] 2> for eachdrb-Identityvalue that is part of the current UE configuration:

[0075] 3> if this DRB is an AM DRB:

[0076] 4> after the end of this procedure, trigger the PDCP entity of this DRB to perform data recovery as specified in TS 38.323 [5], after applying the LTM configuration inltm-CandidateConfigwithinLTM-CandidateIE inltm-Config;

[0077] 2> if the value of fieldltm-NoResetID contained within theLTM-CandidateIE inltm-Configindicated by lower layers or for the selected cell in accordance with 5.3.7.3 is not equal to the value ofltm-ServingCellNoResetIDwithinVarLTM-ServingCellNoResetID:

[0078] 3> replace the value ofltm-ServingCellNoResetIDinVarLTM-ServingCellNoResetIDwith the value ofltm-NoResetIDin theLTM-Candidateinltm-Configindicated by lower layers or for the selected cell in accordance with 5.3.7.3;

[0079] 1> if theLTM-CandidateIE inltm-Configindicated by lower layers or for the selected cell in accordance with 5.3.7.3 contains the fieldltm-UE-MeasuredTA-ID:

[0080] 2> if the value ofltm-UE-MeasuredTA-IDis not equal to the value ofltm-ServingCellUE-MeasuredTA-IDwithinVarLTM-ServingCellUE-MeasuredTA-ID:

[0081] 3> replace the value ofltm-ServingCellUE-MeasuredTA-IDinVarLTM-ServingCellUE-MeasuredTA-IDwith the value received withinltm-UE-MeasuredTA-ID;

[0082] 3> for eachLTM-CandidateIE inltm-Config:

[0083] 4> if the value ofltm-UE-MeasuredTA-IDwithinLTM-CandidateIE is equal to the value ofltm-ServingCellUE-MeasuredTA-IDwithinVarLTM-ServingCellUE-MeasuredTA-ID:

[0084] 5> inform lower layers that the UE is configured with UE-based TA measurements for the LTM-Candidate;

[0085] 4> else:

[0086] 5> inform lower layers that the UE is not configured with UE-based TA measurements for the LTM-Candidate;

[0087] NOTE 0: The UE is not expected to perform UE-based TA measurements for an SpCell.

[0088] 1> else if theLTM-CandidateIE inltm-Configindicated by lower layers or for the selected cell in accordance with 5.3.7.3 does not contain the fieldltm-UE-MeasuredTA-ID:

[0089] 2> inform lower layers that the UE is not configured with UE-based TA measurements for theLTM-Candidate.

[0090] 1> ifltm-ConfigCompleteis not included within theLTM-CandidateIE inltm-Configindicated by lower layers or for the selected cell in accordance with 5.3.7.3:

[0091] 2> considerltm-ReferenceConfigurationinltm-Config, associated with the cell group for which the LTM cell switch procedure is triggered, to be the current UE configuration for the fields and configurations to be released by the actions above in this procedure;

[0092] 2> ifmeasConfigis included withinltm-ReferenceConfigurationinltm-Config;

[0093] 3> perform the measurement configuration procedure as specified in clause 5.5.2 by considering themeasConfigwithinltm-ReferenceConfigurationinltm-Configas the receivedmeasConfig:

[0094] NOTE 1: When the UE considers the reference configuration to be the current UE configuration, the UE should store fields and configurations that are part of the reference configuration but should not execute any actions or procedures triggered by the reception of anRRCReconfigurationmessage which are described in clause 5.3.5.3, unless specified otherwise in this clause.

[0095] 1> if the LTM cell switch is triggered by an indication from lower layers:

[0096] 2> apply theRRCReconfigurationmessage inltm-CandidateConfigwithinLTM-CandidateIE inltm-Configidentified by the LTM candidate configuration identity received from lower layers according to clause 5.3.5.3;

[0097] 1> else (LTM cell switch triggered upon cell selection performed while timer T311 was running):

[0098] 2> apply theRRCReconfigurationmessage inltm-CandidateConfigwithinLTM-CandidateIE inltm-Configrelated to the LTM candidate configuration identity for the selected cell (i.e., in accordance with 5.3.7.3) according to clause 5.3.5.3;

[0099] 1> release the radio bearer(s) and the logical channel(s) that were part of the UE configuration before of this LTM cell switch procedure but not part of the LTM candidate configuration either indicated by lower layers or for the selected cell in accordance with 5.3.7.3, or the LTM reference configuration (in case the LTM candidate configuration does not includeltm-ConfigComplete).

[0100] NOTE 2: Whenltm-ConfigCompleteis not included for an LTM candidate configuration, before an LTM cell switch is triggered a UE implementation may generate and store anRRCReconfigurationmessage by applying the received LTM candidate configuration on top of the LTM reference configuration, and the storedRRCReconfigurationmessage is applied when the LTM cell switch is triggered. It is up to the UE to ensure that the RRC reconfiguration applied at the time of LTM cell switch is in accordance with the latest LTM reference configuration and LTM candidate configuration.

[0101] In Release 18, only intra-CU LTM cell switch is supported. In Rel-19, inter-CU LTM cell switch will be introduced. With respect to dual connectivity, the following scenarios can coexist:

[0102] - Inter-MN LTM and intra-SN LTM

[0103] - Inter-SN LTM and intra-MN LTM

[0104] Network implementation avoids the simultaneous execution for both MCG and SCG LTM. In Release 19, inter-CU MCG LTM with intra-SN PSCell change will be supported, but the methods for supporting the Release 19 LTM is unknown.

[0105] A UE may be configured with following signaling radio bearers on the MCG:

[0106] - SRB0 is for RRC messages using the CCCH logical channel (except SRB0 of L2 U2N Remote UE); It is not configured using dedicated RRC signalling.

[0107] - SRB1 is for RRC messages (which may include a piggybacked NAS message) as well as for NAS messages prior to the establishment of SRB2, all using DCCH logical channel (except SRB1 of L2 U2N Remote UE);

[0108] - SRB4 is for RRC messages which include application layer measurement report information, all using DCCH logical channel. SRB4 has a lower priority than SRB1 and can only be configured by the network after AS security activation. There are further discussions on using SRB4 for other purposes such as for reporting measurements used for AI / ML in NR, for e.g. for beam management; and

[0109] - SRBx for sending UEInformationResponse message containing AI / ML related data.

[0110] Version 18.4.0 of TS 38.331, 38.321, 38.306, 37.340, 38.300 are considered as background.

[0111] V18.4.0 of TS 38.331 specifies the mechanism for including SCG configuration using mrdc-SecondaryCellGroup in the RRCReconfiguration message. If the network wants to setup SCG, it includes mrdc-SecondaryCellGroup in the RRCReconfiguration message.

[0112] RRCReconfiguration-v1560-IEs ::= SEQUENCE { mrdc-SecondaryCellGroupConfig SetupRelease { MRDC-SecondaryCellGroupConfig } OPTIONAL, -- Need M

[0113] }

[0114] MRDC-SecondaryCellGroupConfig ::= SEQUENCE {

[0115] mrdc-ReleaseAndAdd ENUMERATED {true} OPTIONAL, -- Need N

[0116] mrdc-SecondaryCellGroup CHOICE { nr-SCG OCTET STRING (CONTAINING RRCReconfiguration),

[0117] eutra-SCG OCTET STRING

[0118] }

[0119] V18.4.0 of TS 38.331 specifies the details for configuring LTM and the LTM candidates. According to this specification, LTM configuration can include LTM reference configuration, LTM candidate configuration, Configuration of the LTM CSI resources etc. LTM candidate configuration may include the configuration of the reference signals to be measured, configuration related to early uplink and early downlink synchronization, ltm-CandidateConfig which contain the RRCReconfiguration message used to configure an LTM candidate configuration either as a complete configuration or in conjunction with a reference configuration etc.

[0120] There are three ways by which UE can receive the LTM configuration-

[0121] a. The UE may receive the LTM configuration included within an RRCReconfiguration message received via SRB1. This is associated with the MCG and includes the MCG configuration.

[0122] b. The UE may receive the LTM configuration via SRB3. This is associated with the SCG and includes the SCG configuration.

[0123] c. The UE may receive the LTM configuration embedded in an RRCReconfiguration message received via SRB1. This is associated with the SCG and includes the SCG configuration.

[0124] The existing mechanisms do not provide any procedure for how the UE handles current common and dedicated configurations related to MCG with respect to the execution of LTM cell switch triggered on SCG and how the UE handles SRB5 during LTM cell switch. Similarly, the existing mechanisms do not provide any procedure for how the UE handles current common and dedicated configurations related to SCG with respect to the execution of LTM cell switch triggered on MCG.

[0125] Hence, there is a need in the art for solutions which will overcome the above mentioned drawback(s), among others.

[0126] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0127] For the purposes of interpreting this specification, the definitions (as defined herein) will apply and whenever appropriate the terms used in singular will also include the plural and vice versa. It is to be understood that the terminology used herein is for the purposes of describing particular embodiments only and is not intended to be limiting. The terms "comprising", "having" and "including" are to be construed as open-ended terms unless otherwise noted.

[0128] The words / phrases "exemplary", "example", "illustration", "in an instance", "and the like", "and so on", "etc.", "etcetera", "e.g.," , "i.e.," are merely used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein using the words / phrases "exemplary", "example", "illustration", "in an instance", "and the like", "and so on", "etc.", "etcetera", "e.g.," , "i.e.," is not necessarily to be construed as preferred or advantageous over other embodiments.

[0129] Embodiments herein may be described and illustrated in terms of blocks which carry out a described function or functions.　These blocks, which may be referred to herein as managers, units, modules, hardware components or the like, are physically implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and may optionally be driven by a firmware. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like.　The circuits constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block.　Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the disclosure.　Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the disclosure.

[0130] It should be noted that elements in the drawings are illustrated for the purposes of this description and ease of understanding and may not have necessarily been drawn to scale. For example, the flowcharts / sequence diagrams illustrate the method in terms of the steps required for understanding of aspects of the embodiments as disclosed herein. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Furthermore, in terms of the system, one or more components / modules which comprise the system may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0131] The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any modifications, equivalents, and substitutes in addition to those which are particularly set out in the accompanying drawings and the corresponding description. Usage of words such as first, second, third etc., to describe components / elements / steps is for the purposes of this description and should not be construed as sequential ordering / placement / occurrence unless specified otherwise.

[0132] Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.

[0133] In describing the embodiments, descriptions related to technical contents well-known in the art and not associated directly with the disclosure will be omitted. Such an omission of unnecessary descriptions is intended to prevent obscuring of the main idea of the disclosure and more clearly transfer the main idea.

[0134] For the same reason, in the accompanying drawings, some elements may be exaggerated, omitted, or schematically illustrated. Further, the size of each element does not completely reflect the actual size. In the drawings, identical or corresponding elements are provided with identical reference numerals or different reference numerals.

[0135] The advantages and features of the disclosure and ways to achieve them will be apparent by making reference to embodiments as described below in detail in conjunction with the accompanying drawings. However, the disclosure is not limited to the embodiments set forth below but may be implemented in various different forms. The following embodiments are provided only to completely disclose the disclosure and inform those skilled in the art of the scope of the disclosure, and the disclosure is defined only by the scope of the appended claims. Throughout the specification, the same or like reference numerals designate the same or like elements. Furthermore, in describing the disclosure, a detailed description of known functions or constitution incorporated herein will be omitted in the case that it is determined that the description may make the subject matter of the disclosure unnecessarily unclear. The terms which will be described below are terms defined in consideration of the functions in the disclosure, and may be different according to users, intentions of the operators, or customs. Therefore, the definitions of the terms should be made based on the contents throughout the specification.

[0136] Herein, it will be understood that each block of the flowchart illustrations, and combinations of blocks in the flowchart illustrations, may be performed based on computer program instructions. These computer program instructions may be loaded individually or collectively onto at least one processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which perform through any one of, or in any combination of, the at least one processor of the computer or other programmable data processing apparatus, create means for performing the functions specified in the flowchart block(s). These computer program instructions may also be stored in a non-transitory computer usable or computer-readable memory that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer usable or computer-readable memory produce an article of manufacture including instruction means that perform the function specified in the flowchart block(s). The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable data processing apparatus to produce a computer executed process such that the instructions that perform on the computer or other programmable data processing apparatus provide steps for executing the functions specified in the flowchart block(s).

[0137] Further, each block may represent a module, segment, or portion of code, which includes one or more executable instructions for executing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of the order. For example, two blocks (or functions) shown in succession may in fact be performed substantially concurrently or the blocks may sometimes be performed in the reverse order, depending upon the functionality involved.

[0138] As used in embodiments of the disclosure, a "~unit / module" may refer to a software element or a hardware element, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), which performs a predetermined function. However, the term including the word "~unit / module" does not always have a meaning limited to software or hardware. The "~unit / module" may be constructed either to be stored in an addressable storage medium or to execute one or more processors. Therefore, the "~unit / module" includes, for example, software elements, object-oriented software elements, components such as class elements and task elements, processes, functions, properties, procedures, sub-routines, segments of a program code, drivers, firmware, micro-codes, circuits, data, database, data structures, tables, arrays, and parameters. The components and functions provided by the "~unit / module" may be either combined into a smaller number of components and a "~unit / module," or divided into additional components and a "~unit / module." Moreover, the components and "~units / module" may be implemented to reproduce one or more central processing units (CPUs) within a device or a security multimedia card. Further, in the embodiments, the "쪟unit / module" may include one or more processors.

[0139] The entirety of the one or more computer programs may be stored in a single memory device, or the one or more computer programs may be divided with different portions stored in different multiple memory devices.

[0140] Any of the functions or operations described herein can be processed by one processor or a combination of processors. The one processor or the combination of processors is circuitry performing processing and includes circuitry like an application processor (AP, e.g. a CPU), a communication processor (CP, e.g., a modem), a graphics processing unit (GPU), a neural processing unit (NPU) (e.g., an artificial intelligence (AI) chip), a Wi-Fi chip, a Bluetooth® chip, a global positioning system (GPS) chip, a near field communication (NFC) chip, connectivity chips, a sensor controller, a touch controller, a finger-print sensor controller, a display driver integrated circuit (IC), an audio CODEC chip, a universal serial bus (USB) controller, a camera controller, an image processing IC, microprocessors, microcontrollers, digital　signal processors, FPGA, ASIC, a microprocessor unit (MPU), a system on chip (SoC), an IC, or the like. The one processor or the combination of processors executes instructions that can be stored in a memory, such as the　operating system, in order to control the overall operation of the device.　Also, the one processor or the combination of processors is also capable of executing other processes and programs　resident in the memory, such as processes for the disclosure.

[0141] It will be appreciated that various embodiments of the disclosure according to the claims and description in the specification can be realized in the form of hardware, software or a combination of hardware and software.

[0142] Any such software may be stored in non-transitory computer readable storage media. The non-transitory computer readable storage media store one or more computer programs (software modules), the one or more computer programs include computer-executable instructions that, when executed by one or more processors of an electronic device individually or collectively, cause the electronic device to perform a method of the disclosure. Additionally, or alternatively, such software may be a computer program [product] comprising instructions which, when executed by one or more processors of an electronic device individually or collectively, cause the electronic device to perform a method of the disclosure.

[0143] Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like read only memory (ROM), whether erasable or rewritable or not, or in the form of memory such as, for example, random access memory (RAM), memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a compact disk (CD), digital versatile disc (DVD), magnetic disk or magnetic tape or the like. It will be appreciated that the storage devices and storage media are various embodiments of non-transitory machine-readable storage that are suitable for storing a computer program or computer programs comprising instructions that, when executed, implement various embodiments of the disclosure. Accordingly, various embodiments of the present disclosure may provide a program comprising code for implementing apparatus or a method as claimed in any one of the claims of this specification and a non-transitory machine-readable storage storing such a program.

[0144] Hereinafter, the determination of priority between A and B in the present disclosure may refer to various actions such as selecting the one having a higher priority based on a predefined priority rule and performing an operation corresponding thereto or omitting or dropping an operation corresponding to the one having a lower priority.

[0145] Hereinafter, "A or B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0146] In addition, "at least one of A, B, and C" as described in the present disclosure may be understood to include A, or B, or C, or any combination of A, B, and C.

[0147] In addition, "at least one of A, B, or C" as described in the present disclosure may be understood to include A, or B, or C, or any combination of A, B, and C.

[0148] Furthermore, "A / B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0149] Furthermore, "A, B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0150] Furthermore, "A and B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0151] Furthermore, "if condition A and condition B are satisfied," as described in the present disclosure, may not be limited to a case where both condition A and condition B are satisfied, but may be understood to include a case where either condition A or condition B is individually satisfied, both condition A and condition B are satisfied, or one or more additional conditions are satisfied in combination.

[0152] Furthermore, throughout this disclosure, ordinal terms such as "first," "second," "third," etc., (and similar qualifiers) are used merely to distinguish between different instances, occurrences, configurations, messages, stages, elements or aspects of elements, operations, or information as described herein. Unless the context clearly dictates otherwise, the use of such ordinal terms does not itself require that the elements, operations, or information distinguished by these terms be structurally different, numerically distinct, or substantively dissimilar. For example, a "first signal" and a "second signal" may refer to instances of the same signal transmitted at different times or containing the same core information despite minor variations, or they may refer to signals with different content or characteristics, depending on the specific context. Similarly, a "first value" and a "second value" may represent the same magnitude but measured or applied in different circumstances, or they may represent different magnitudes. The interpretation should be guided by the specific technical context, function, and relationship described in the relevant portion of the specification and claims.

[0153] Furthermore, the terms "first ~", "second ~", etc., as described in the present disclosure with respect to various elements (e.g., information, objects, operation, sequences, or the like), should not limit those elements. These terms may only be intended to distinguish one element from another and may not be intended to indicate a specific order. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element.

[0154] Furthermore, even if "first ~" and "second ~" are described in the present disclosure, it may be understood that element(s) referred to by "first ~" and "second ~" may be the same or different. For example, in case of element(s) being information, first information and second information may both be the same information, and, in some cases, are separate and different information.

[0155] In addition, the terms "if ~" and "in case that ~" as used in the disclosure or claims may be interpreted to include the meanings of "when (or upon) ~," "in response to ~," "based on ~," or "according to ~," and may be used interchangeably with these expressions. In addition, expressions other than those exemplified herein may also be used, as long as they have substantially the same meaning and do not impair the technical features of the present disclosure. If a method step (e.g., transmit a signal) is performed according to the disclosure of the application in connection with one of the above terms (such as "in case that ~" or the like), it may be interpreted to include the meanings (disclosure) of a prior determination that a feature has a specific state "~" (e.g., a bit length is above X), and then perform the method step in response to said determination.

[0156] In addition, the term "not perform" as used in the present disclosure or claims may, in context, be understood to mean that the corresponding step is omitted or skipped. Such a term may be replaced with other terms having the same or substantially equivalent meaning.

[0157] In addition, "transmitting a message including A and B" as described in the present disclosure, may be understood as encompassing both (i) transmitting A and B in a single message, and (ii) transmitting A and B separately via multiple messages (e.g., transmitting a first message including A and a second message including B). This interpretation may also apply to messages that include two or more items (e.g., A, B, C), transmitted either together or separately.

[0158] In addition, "transmitting a message including A and transmitting a message including B" may also be interpreted as transmitting a message including A and B in a single message.

[0159] In the specific embodiments of the present disclosure described below, terms or components included in the disclosure may be expressed in singular or plural form depending on the specific embodiments presented. However, such singular or plural expressions are selected appropriately for convenience of description, and the present disclosure is not limited to a singular or plural number of components. A component expressed in the plural form may be implemented as a single component, and a component expressed in the singular form may be implemented as multiple components.

[0160] The drawings or flowcharts described below illustrate example methods that may be implemented according to the principles of the present disclosure, and various modifications may be made to the methods illustrated in the flowcharts of the present disclosure. For example, although illustrated as a series of steps, various steps in each drawing or flowchart may overlap, occur in parallel, occur in a different order, or be repeated. In other examples, any step may be omitted or replaced with another step.

[0161] The process of the flowchart may be performed by a device. One or more of the steps of the　flowchart can be implemented by one or more processors / computer programs executing　instructions to perform the noted functions.

[0162] The methods and apparatuses proposed in the embodiments of the present disclosure may be disclosed in connection with drawings disclosing flowcharts to illustrate example methods that may be implemented according to the principles of the present disclosure. Such flowcharts may contain different branches and / or sub-branches. It is understood that the principles of the present disclosure do not only contain the combination of all branches / sub-branches disclosed in the embodiment, but the present disclosure also contains at least one isolated branch / isolated sub-branch, in particular to a single branch / single sub-branch.

[0163] The methods and apparatuses proposed in the embodiments of the present disclosure are not limited to each embodiment individually but may also be applied in combination of all or some of the embodiments proposed in the disclosure. Therefore, the embodiments of the present disclosure may be modified and applied without significantly departing from the scope of the present disclosure, as would be understood by those skilled in the art.

[0164] In this case, even if certain wordings are described differently across embodiments, they may be used interchangeably or in substitution or in combination if their underlying concepts are equivalent. For example, for the same or equivalent concept, even if one embodiment uses the expression "A" and another embodiment uses the expression "B", such expressions may be understood interchangeably, in substitution, or in combination.

[0165] The terms used in the following description to refer to access nodes, network entities, messages, interfaces between network entities, various types of identification information, and the like, are provided merely for the convenience of explanation by way of example. Therefore, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may also be used. Such terms may also be interchangeable with terms defined in any 3rd generation partnership project　(3GPP) technical specifications (TS) or similar technical specifications, e.g., from ETSI, where appropriate.

[0166] Hereinafter, a base station (BS) is an entity that allocates resources to terminals, and may be at least one of a gNodeB, an eNodeB, a NodeB, a 6G base station, a sNodeB, a wireless access unit, a BS controller, or a node on a network.

[0167] Furthermore, the base station of the present disclosure may include a split architecture comprising a central unit (CU) and a distributed unit (DU). In this structure, the CU is configured to process the higher layers of the control and user planes, while the DU is configured to process lower-layer radio resource functions. The embodiments of the present disclosure may be equally applicable to 5G base station architectures in which such CU and DU functional splits are implemented.

[0168] A terminal may include a UE, a mobile station (MS), a cellular phone, a smartphone, a computer, a tablet, a wearable device, an Internet of Things (IoT) device, or any other device / system capable of performing communication functions.

[0169] In the disclosure, a downlink (DL) refers to a radio link through which a BS transmits a signal to a terminal, and an uplink (UL) refers to a radio link through which a terminal transmits a signal to a BS.

[0170] Furthermore, hereinafter, 5th generation (5G) mobile communication technologies (e.g., 5G new radio (NR)), 6th generation (6G) mobile communication technologies may be described by way of example, but the embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, newly evolved mobile communication systems developed after 5G and 6G may be included. Furthermore, based on determinations by those skilled in the art, the embodiments of the present disclosure may also be applied to other communication systems (e.g., Wi-Fi systems) through some modifications without significantly departing from the scope of the present disclosure

[0171] In the following description, the terms physical channel and signal may be used interchangeably with data or control signal. For example, the term physical downlink shared channel (PDSCH) refers to a physical channel through which data is transmitted, but the term PDSCH may also be used to refer to the data itself. That is, in the present disclosure, the expression "transmit a physical channel" may be interpreted as being equivalent to the expression "transmit data or a signal via a physical channel."

[0172] Hereinafter, in the context of the present disclosure, higher layer signaling may refer to signaling corresponding to at least one or any combination of the following: master information block (MIB), system information block (SIB) or SIB M (M = 1, 2, ...), radio resource control (RRC), or medium access control (MAC) control element (CE), or a non-access stratum (NAS) signaling message, or an application layer message. The RRC signaling message may be referred to as Layer 3 (L3) signaling.

[0173] In addition, Layer 1 (L1) signaling may refer to signaling corresponding to at least one or any combination of signaling techniques using the at least one or any combination of the following physical layer channels or signaling: physical downlink control channel (PDCCH), downlink control information (DCI), user equipment (UE)-specific DCI, group-common DCI, common DCI, scheduling DCI (e.g., DCI used for scheduling downlink or uplink data), non-scheduling DCI (e.g., DCI not used for scheduling downlink or uplink data) physical uplink control channel (PUCCH), or uplink control information (UCI). The L1 signaling message may be referred to as a physical layer signaling.

[0174] For example, the physical layer signaling (i.e., L1 signaling) may include downlink control information (DCI). In addition, the higher layer signaling may include a medium access control (MAC) control message, a radio resource control (RRC) signaling message, a non-access stratum (NAS) signaling message, or an application layer message. The RRC signaling message may be referred to as L3 signaling. It should be noted, however, that the higher layer signaling is not limited to the aforementioned examples.

[0175] Hereinafter, the expression that information is configured by the BS, as used in the present disclosure or claims, may, in context, be understood to mean that the terminal receives the corresponding information from the BS via a physical layer signaling or a higher layer signaling. Such an expression may be replaced with other terms having the same or substantially equivalent meaning.

[0176] Hereinafter, the operational principle of the present disclosure will be described in detail with reference to the accompanying drawings.

[0177] The embodiments herein achieve methods and systems for managing a Lower-Layered Triggered Mobility (LTM) Cell Switch, wherein the LTM Cell Switch is triggered by a Master Cell Group (MCG) in a wireless communication network. Referring now to the drawings, and more particularly to FIGS. 1 through 8, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.

[0178] Embodiments herein disclose methods for performing LTM cell switch as in section 5.3.5.18.6 of TS 38.331. In an embodiment herein, the LTM cell switch may be performed, on receiving an indication from the lower layers that an LTM cell switch procedure is triggered, or upon performing LTM cell switch following cell selection performed while timer T311 was running, as specified in section 5.3.7.3 of TS 38.331.

[0179] FIG. 1 is a block diagram of a terminal or user equipment (UE) 100. The terminal (i.e., the UE) is an electronic device capable of wireless communication and having various form factors, examples of the terminal may include a UE, a mobile station (MS), a cellular phone, a smartphone, a computer, a tablet, a wearable device, an Internet of Things (IoT) device, or any other device / system capable of performing wireless communication with a base station (BS) and / or another terminal through a wireless channel.

[0180] Referring to FIG. 1, the UE 100 may include at least one transceiver (hereinafter, referred to as simply "transceiver") 101, at least one processor (hereinafter, referred to as simply "processor") 102, and at least one memory (hereinafter, referred to as simply "memory") 103. According to at least one or a combination of methods corresponding to the embodiments described in the present disclosure, the transceiver 101, the processor 102, and the memory 103 of the UE 100 may operate. However, components of the UE 100 are not limited to the example components illustrated in FIG. 1. In another embodiment, the UE 100 may further include additional components in addition to the above-mentioned components, or some components may be omitted. Further, in some embodiments, any combination of the transceiver 101, the processor 102, or the memory 103 may be integrated in the form of one component.

[0181] The transceiver 101 may be a communication circuit or communication circuitry that enables the UE 100 to perform wireless communication with a node or an entity of a network. For example, the transceiver 101 may enable the UE 100 to transmit or receive a signal to or from a BS through cellular communication, or to transmit or receive a signal to or from another UE through cellular communication. For example, the transceiver 101 may support at least one of various cellular communication technologies including 3rd generation (3G), 4th generation (4G), long term evolution (LTE), 5th generation (5G) NR, 6th generation (6G), and various cellular wireless communication technologies supported by the transceiver (101) may include all subsequent generations of evolved wireless communications.

[0182] According to an embodiment, the transceiver 101 may include various circuit structures used to transmit or receive signals to or from a BS through a wireless channel. The signals may include control information and data. For example, the transceiver 101 may include a radio frequency (RF) transmitter for up-converting and amplifying the frequency of a transmitted signal and an RF receiver for low-noise-amplifying a received signal and down-converting the frequency thereof. The transceiver 101 may output a signal received through a wireless channel to the processor 102 and may transmit, through a wireless channel, a signal output from the processor 102.

[0183] According to an embodiment, the UE 100 may include a plurality of transceivers. For example, in the case of supporting evolved-universal terrestrial radio access-new radio (E-UTRA-NR) dual connectivity (EN-DC), the UE 100 may include a first transceiver supporting the 4G LTE wireless communication and a second transceiver supporting the 5G NR wireless communication. According to another embodiment, in the case of supporting NR-dual connectivity (NR-DC), the UE 100 may include a plurality of transceivers supporting the 5G NR wireless communication. According to still another embodiment, in the case of supporting near field wireless communication, the UE 100 may separately include a transceiver supporting at least one standard in the group of wireless communication protocol standards as defined in the protocol standards for Bluetooth, wireless local area network (WLAN) network (including institute of electrical and electronics engineers (IEEE) 802.11-2016 standard or its amendments, e.g., 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be, without being limited thereto).

[0184] The processor 102 may control general operations of the UE 100 according to embodiments of the disclosure. The processor 102 may be implemented by one or more integrated circuit (or circuitry) (IC) chips and may execute various data processing operations. The processor 102 may include at least one electric circuit, and may execute instructions (or a program, codes, data, etc.) stored in the memory 103, individually, collectively or in any combination thereof. Further, the processor 102 may include a single-core processor or multi-core processor and may include a processor assembly including a plurality of processing circuits (circuitry) according to a specific implementation scheme.

[0185] The processor 102 may be electrically, operatively, and / or communicatively coupled to the transceiver 101 to control the transceiver 101.

[0186] The processor 102 may include at least one processor (or processing circuitry), and the at least one processor may perform the following operations individually, collectively or in any combination thereof. For example, the processor 102 may include a communication processor (CP) configured to control communication operations and an application processor (AP) configured to control execution of an upper layer (for example, an application layer). In a specific embodiment, at least a part of the processor 102 may be included in one chip and the other part of the processor 102 may be included in another chip. Otherwise, at least one processor may be included in another component, for example, the transceiver 101 or the memory 103.

[0187] The processor 102 may perform or control or cause an operation of the UE 100 for executing at least one or a combination of methods according to embodiments of the disclosure. For example, the processor 102 may control operations of the UE 100 for processing a downlink signal received from a BS or generating and transmitting an uplink signal to a BS. To this end, the processor 102 may execute a computer program, codes, or instructions stored in the memory 103, so as to control other components of the UE 100 to enable execution of various operations.

[0188] The memory 103 corresponds to a hardware storage device capable of temporarily or permanently storing information and may include one or more storage media. For example, the memory 103 may include a memory assembly including one or more storage media. For example, the one or more storage media may include permanent memory, such as a hard drive, flash memory, or read-only memory (ROM), semipermanent memory, such as random access memory (RAM), cache memory, or a combination thereof.

[0189] The memory 103 may be electrically, operatively, and / or communicatively coupled to the processor 102 and may be accessed by the processor 102.

[0190] The memory 103 may store a computer program, codes, or instructions executable by the processor 102. According to an embodiment, a computer program, codes, or instructions executable by the processor 102 may be either stored in a single memory device or separated and stored in a distributed manner in two or more memory devices. By executing the instructions stored in the memory 103, the processor 102 may perform various functions according to an embodiment of the disclosure.

[0191] According to an embodiment of the disclosure, operations of the UE 100 may be caused to be performed based on execution of instructions (or a computer program or codes) stored in the memory 103 by at least one processor (or processing circuitry) configured to execute the same individually, collectively, or in any combination thereof, based on processing circuitry that is not configured to execute instructions, and / or based on components of processing circuitry that is not configured to execute instructions.

[0192] The processor 102 can receive LTM configuration for the SCG LTM cell switch, wherein the received configuration is associated with the MCG. SCG LTM cell switch is the LTM cell switch on SCG, i.e. to change the PSCell, such as when SN sends the command for LTM cell switch or the UE executes conditional LTM cell switch for SCG. LTM configuration is associated with the MCG if the LTM configuration includes the MCG configuration. The UE 100 can be configured for dual connectivity and has a Primary secondary cell (PSCell). On LTM cell switch being triggered on the SCG, the processor 102 can release a first set of configurations associated with the MCG. On LTM cell switch being triggered on the SCG, the processor 102 can further retain (i.e., not release) a second set of configurations associated with the MCG. The first set of configurations comprises dedicated and common radio configurations which have not been received via SRB1 within a mrdc-SecondaryCellGroup; and dedicated and common radio configurations which have not been received via SRB3. As illustrated in the background, mrdc-SecondaryCellGroup includes the SCG configuration while it is send in SRB1. In NR-DC, SRB3 is used only for SCG configuration. Thus dedicated and common radio which have not been received via SRB3 means configuration which is not SCG configuration, i.e. the MCG configuration. Releasing the first ste pf configurations, i.e. releasing the MCG configuration allows the UE to use reference configuration for LTM cell switch triggered on the SCG when the configuration to be applied at the time of the cell switch includes the MCG configuration also as the network can configure the MCG configuration without considering the current configuration of the PCell. The second set of configurations comprises a radio bearer configuration, a MCG Cell Radio Network Temporary Identifier (C-RNTI), at least one Access Stratum (AS) security configuration associated with a master key, a logged measurement configuration; and ServingCellConfigCommon of a Primary Cell (PCell). The second set of configuration includes MCG C-RNTI, wherein the MCG C-RNTI can be used to decode any Downlink Control Information (DCI) addressed to it. If the second set of configurations does not include the MCG C-RNTI, the UE will release the MCG C-RNTI and will not be able to receive any scheduling. The second set of configuration includes the AS security configuration associated with a master key, wherein the AS security configuration will help to avoid lower layer reestablishment and data recovery. Keeping the AS security configuration is thus important to keep the UE performance intact. The second set of configuration includes a logged measurement configuration so that the UE can perform logged measurements, if the UE moves to RRCRelease without receiving another set of configuration from the network. The second set of configuration includes ServingCellConfigCommon of a Primary Cell (PCell), wherein the ServingCellConfigCommon enables the UE to not reapply the common configuration of the PCell during SCG LTM cell switch. This gives sufficient signalling benefits as the network apparatus does not have to include the serving cell common configuration in the candidate configuration or reference configuration.

[0193] Release of SCG configuration during LTM cell switch triggered on MCG:

[0194] In an embodiment herein, while performing LTM cell switch, and the LTM cell switch is triggered on the MCG, the processor 102 can release / clear the current dedicated configurations associated with the SCG, except a few specific configurations (Cx) based on one or more conditions.

[0195] In an embodiment herein, while performing LTM cell switch by the UE 100 (such as in section 5.3.5.18.6 of TS 38.33), and the LTM cell switch is triggered on MCG, the processor 102 can release / clear current dedicated configurations associated with SCG by the UE 100 if the MCG RRCConfiguration applied during the LTM cell switch contains configuration for PSCellChange. Current configuration as disclosed herein can mean the configuration of the UE 100, when the UE 100 performs LTM cell switch execution, such as specified in TS 38.331.

[0196] In an embodiment herein, while performing LTM cell switch triggered on SCG, the processor 102 releases / clears the current dedicated configurations associated with MCG, except a few specific configurations (Cx) based on some conditions. A configuration associated with MCG is the configuration related to MCG operation (operation of PCells and SCells for the MCG).

[0197] In an embodiment herein, while performing LTM cell switch triggered on SCG, the processor 102 releases / clears current dedicated configurations associated with MCG, if the LTM cell switch is inter-CU SN LTM cell switch or intra-CU SN LTM cell switch and the LTM configuration is associated with the MCG. In NR, LTM configuration for inter-CU SN LTM cell switch is always associated with the MCG, while the LTM configuration for intra-CU SN LTM cell switch can be associated with either MCG or SCG.

[0198] In an embodiment, in NR, while performing LTM cell switch triggered on SCG, the processor 102 releases / clears current dedicated configurations associated with MCG if the applied LTM configuration (ltm-config) is included within an RRCReconfiguration message received via SRB1.

[0199] FIG. 2 depicts a process for performing MCG LTM cell switch execution. In step 201, the UE 100 is configured for dual connectivity and has a PSCell. In step 202, the processor 102 receives LTM configuration for MCG via the transceiver 101 (order of steps 201 and 202 are interchangeable). In step 203, the processor 102 performs LTM cell switch, triggered on MCG. The RRCReconfiguration message applied due to the LTM cell switch execution procedure such as according to clause 5.3.5.18.6 changes the PSCell also. In step 204, the processor 102 releases / clears the current dedicated configurations associated with SCG, except a few specific configurations (Cx). In NR, the current dedicated configurations associated with SCG which is released / cleared comprises of all current dedicated and common radio configurations which have been received either via SRB1 within mrdc-SecondaryCellGroup, or via SRB3. The various actions in method 200 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 2 may be omitted.

[0200] FIG. 3 depicts a process for performing MCG LTM cell switch execution. In an embodiment, the steps are as follows: At step 301, UE 100 is configured for dual connectivity and has a PSCell. At step 302, the processor 102 receives LTM configuration for SCG LTM cell switch, wherein the configuration is associated with MCG (order of steps 301 and 302 are interchangeable). At step 303, the processor 102 performs LTM cell switch triggered on SCG. At step 304, the processor 102 releases / clears the current dedicated configurations associated with MCG except a few specific configurations (Cx). In NR, the current dedicated configurations associated with the MCG which are released / cleared comprise all current dedicated and common radio configurations which have been received neither via SRB1 within mrdc-SecondaryCellGroup nor via SRB3. The processor 102 also releases / clears the current dedicated configurations associated with SCG except a few specific configurations (Cy). The various actions in method 300 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 3 may be omitted.

[0201] After performing one of the above steps (200 / 300), the processor 102 may apply the MCG RRCReconfiguration and SCG RRCReconfiguration corresponding to the LTM candidate cell. In NR dual connectivity, embodiments disclosed herein may be applied only on NR-DC. If the LTM configuration for SCG LTM cell switch is associated with SCG, the processor 102 releases / clears the current dedicated configurations associated with the SCG and does not release / clear the current dedicated configurations associated with MCG except a few specific configurations (Cy).

[0202] In an embodiment herein, in NR, on the UE 100 performing LTM cell switch triggered on MCG, the processor 102 releases / clears all current dedicated and common radio configurations which have been received either via SRB1 within mrdc-SecondaryCellGroup, or via SRB3 (except a few specific configurations (Cx)), if the RRCReconfiguration message to be applied due to the LTM cell switch execution procedure includes mrdc-SecondaryCellGroup (i.e., includes mrdc-SecondaryCellGroupConfig set to setup).

[0203] In an embodiment herein, on the UE 100 performing LTM cell switch triggered on MCG, the processor 102 releases / clears all current dedicated and common radio configurations associated to SCG (i.e., all current dedicated and common radio configurations which have been received either via SRB1 within mrdc-SecondaryCellGroup, or via SRB3), except a few specific configurations (Cx), if the MCG RRCReconfiguration message to be applied due to the LTM cell switch execution procedure includes SCG RRCReconfiguration message.

[0204] In an embodiment in NR, on the UE 100 performing LTM cell switch triggered on SCG, the processor 102 releases / clears all current dedicated and common radio configurations which have been received neither via SRB1 within mrdc-SecondaryCellGroup nor via SRB3 (except a few specific configurations (Cx)) if the RRCReconfiguration message to be applied due to the LTM cell switch execution is received in a MN RRCReconfiguration message (and not in mrdc-SecondaryCellGroup).

[0205] In an embodiment, on the UE 100 performing LTM cell switch triggered on SCG, the processor 102 releases / clears all current dedicated and common radio configurations associated with MCG (i.e., all current dedicated and common radio configurations which have been received neither via SRB1 within mrdc-SecondaryCellGroup nor via SRB3) except a few specific configurations (Cx) if an MCG RRCReconfiguration message also needs to be applied due to the LTM cell switch.

[0206] In an embodiment herein, the SCG configurations (Cx) that are kept while releasing / clearing of current dedicated configurations associated with SCG during the execution of LTM cell switch (such as in section 5.3.5.18.6 of TS 38.33) triggered on the MCG, according to the above embodiments comprise of the following:

[0207] - the radio bearer configuration (configured viaRadioBearerConfigIE);

[0208] - thelogicalChannelIdentityandlogicalChannelIdentityExtof RLC bearers configured inRLC-BearerConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322;

[0209] - thebh-LogicalChannelIdentityof BH RLC channels configured inBH-RLC-ChannelConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322;

[0210] - the UE variablesVarLTM-ServingCellNoResetIDandVarLTM-ServingCellUE-MeasuredTA-ID; and

[0211] - theltm-Config; and

[0212] - the AS security configurations associated with the secondary key.

[0213] Keeping the LTM configuration avoids the need for re-providing the LTM configuration to the UE 100, every time that the SCG LTM cell switch including the MCG configuration is provided. This enables the configuration of MCG and SCG LTM cell to be switched together. Keeping the UE variables VarLTM-ServingCellNoResetID and VarLTM-ServingCellUE-MeasuredTA-ID prevents the lower layer reestablishment.

[0214] In an embodiment herein, the MCG dedicated and common radio configurations Cx that are kept while releasing / clearing of current dedicated configurations associated with MCG during LTM cell switch triggered on the SCG according to the above embodiments comprise one or more of the following:

[0215] - The radio bearer configuration (configured viaRadioBearerConfigIE)

[0216] - thelogicalChannelIdentityandlogicalChannelIdentityExtof Radio Link Control (RLC)　bearers configured inRLC-BearerConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0217] - thebh-LogicalChannelIdentityof Backhaul (BH) RLC channels configured inBH-RLC-ChannelConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0218] - the UE variablesVarLTM-ServingCellNoResetIDandVarLTM-ServingCellUE-MeasuredTA-ID;

[0219] - the ltm-Config;

[0220] - the MCG Cell Radio Network Temporary Identifier (C-RNTI) (MCG C-RNTI);

[0221] - the Access Stratum (AS) security configurations associated with the master key;

[0222] - the logged measurement configuration; and

[0223] - the ServingCellConfigCommon of the PCell.

[0224] In an embodiment herein, according to TS 38.331,

[0225] 5.3.5.18.6 LTM cell switch execution:

[0226] Upon the indication by lower layers that an LTM cell switch procedure is triggered, or upon performing LTM cell switch following cell selection performed while timer T311 was running, as specified in 5.3.7.3, the processor 102 shall:

[0227] 1> if the LTM cell switch is triggered on the MCG:

[0228] 2> release / clear all current dedicated and common radio configurations which have neither been received via SRB1 withinmrdc-SecondaryCellGroup, nor via SRB3 except for the following:

[0229] - the radio bearer configuration (configured viaRadioBearerConfig)

[0230] - thelogicalChannelIdentityandlogicalChannelIdentityExtof RLC bearers configured inRLC-BearerConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0231] - thebh-LogicalChannelIdentityof BH RLC channels configured inBH-RLC-ChannelConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0232] - the UE variablesVarLTM-ServingCellNoResetIDandVarLTM-ServingCellUE-MeasuredTA-ID;

[0233] - theltm-Config;

[0234] - the MCG C-RNTI;

[0235] - the AS security configurations associated with the master key;

[0236] - the logged measurement configuration;

[0237] 2> if the RRCReconfiguration (to be) applied due to the LTM cell switch includesmrdc-SecondaryCellGroup:

[0238] 3> release / clear all current dedicated and common radio configurations which have either been received via SRB1 withinmrdc-SecondaryCellGroup, or via SRB3 except for the following:

[0239] - the radio bearer configuration (configured viaRadioBearerConfigIE)

[0240] - thelogicalChannelIdentityandlogicalChannelIdentityExtof RLC bearers configured inRLC-BearerConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0241] - thebh-LogicalChannelIdentityof BH RLC channels configured inBH-RLC-ChannelConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0242] - the UE variablesVarLTM-ServingCellNoResetIDandVarLTM-ServingCellUE-MeasuredTA-ID;

[0243] - theltm-Config; and

[0244] - the AS security configurations associated with the secondary key.

[0245] Releasing the SCG configuration enables the UE 100 to use reference configuration for LTM cell switch triggered on the MCG when the configuration to be applied at the time of the cell switch includes the SCG configuration also as the network can configure the SCG configuration without considering the current configuration of the PSCell. The AS security configuration associated with the secondary key is not released as it will help to avoid lower layer reestablishment and data recovery. Keeping the AS security configuration is thus important to keep the performance of the UE 100 intact. Keeping the LTM configuration avoids the need for re-providing the LTM configuration every time SCG LTM cell switch including MCG configuration is provided. This enables the configuration of MCG and SCG LTM cell to be switched together. Keeping the UE variablesVarLTM-ServingCellNoResetIDandVarLTM-ServingCellUE-MeasuredTA-IDprevents the lower layer reestablishment.

[0246] 1> else, if the LTM cell switch is triggered on the SCG:

[0247] 2> release / clear all current dedicated and common radio configurations which have been received either via SRB1 withinmrdc-SecondaryCellGroup, or via SRB3 except for the following:

[0248] - the radio bearer configuration (configured viaRadioBearerConfigIE)

[0249] - the logicalChannelIdentityandlogicalChannelIdentityExtof RLC bearers configured inRLC-BearerConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0250] - thebh-LogicalChannelIdentityof BH RLC channels configured inBH-RLC-ChannelConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0251] - the UE variablesVarLTM-ServingCellNoResetIDandVarLTM-ServingCellUE-MeasuredTA-ID;

[0252] - theltm-Config; and

[0253] - the AS security configurations associated with the secondary key;

[0254] 2> if the ltm-Config is associated with the MCG

[0255] 3> release / clear all current dedicated and common radio configurations which have neither been received via SRB1 within mrdc-SecondaryCellGroup, nor via SRB3 except for the following:

[0256] - the radio bearer configuration (configured viaRadioBearerConfig)

[0257] - thelogicalChannelIdentityandlogicalChannelIdentityExtof RLC bearers configured inRLC-BearerConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0258] - thebh-LogicalChannelIdentityof BH RLC channels configured inBH-RLC-ChannelConfigand the associated RLC entities, their state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value, as specified in TS 38.322 [4];

[0259] - the UE variablesVarLTM-ServingCellNoResetIDandVarLTM-ServingCellUE-MeasuredTA-ID;

[0260] - theltm-Config;

[0261] - the MCG C-RNTI;

[0262] - the AS security configurations associated with the master key;

[0263] - the logged measurement configuration;

[0264] - theServingCellConfigCommonof the PCell.

[0265] The UE 100 releasing the configuration associated to SCG- helps the MCG to include SCG configuration in the MCG LTM configuration which can be used for subsequent LTM. Without this embodiment herein, the current dedicated and common configuration will impact the configuration for the candidate cells, thereby making it too complex to perform subsequent LTM cell switch including SCG configuration; i.e., PSCell change cannot be performed with subsequent MCG LTM without this embodiment.

[0266] In an embodiment herein, while performing LTM cell switch by the UE 100, and the LTM cell switch being triggered on MCG, the processor 102 releases / clears current dedicated configurations associated with SCG, if the MCG RRCConfiguration applied during the LTM cell switch releases the PSCell or maintains the PSCell without any change.

[0267] In an embodiment herein, a gNB includes mrdc-SecondaryCellGroup IE only in LTM candidate configuration and not in reference configuration. According to this embodiment herein, the UE 100 does not receive mrdc-SecondaryCellGroupConfig set as setup in LTM reference configuration.

[0268] Embodiments disclosed herein allow the network to include the MCG configuration in the reference configuration and LTM candidate configuration separately for Inter-CU SN LTM. It also allows the network to configure intra-CU SN LTM simultaneously with the inter-CU SN LTM.

[0269] When the reference configuration mechanism is used, if the processor 102 does not apply embodiments as disclosed herein, during inter-CU SN LTM or the intra-CU SN LTM configured together with inter-CU SN LTM, as an existing configuration with the need code Need M or Need S (according to the Need code definitions in NR TS 38.331) in the PCell may interfere with the new configuration applied after the cell switch.

[0270] In an embodiment herein, the processor 102 may skip release / clear of the current dedicated configurations associated with MCG during the LTM cell switch execution triggered on SCG if the MCG RRC configuration is not changed.

[0271] Handling of application of Default configuration for SRB:

[0272] While performing LTM cell switch (as in section 5.3.5.18.6 of TS 38.331), the processor 102 applies the default SRB configuration for SRB1 and SRB2 and avoids applying the default SRB configuration for SRB4 or SRBx.

[0273] FIG. 4 depicts a process for applying default SRB during LTM cell switch. In step 401, the UE 100 is configured with SRB1,SRB2 and at least one of SRB4 or SRBx. In step 402, the processor 102 receives LTM configuration for MCG (order of steps 401 and 402 are interchangeable). In step 403, the processor 102 performs LTM cell switch (as in section 5.3.5.18.6 of TS 38.331). While performing LTM cell switch, in step 404, the processor 102 applies the default SRB configuration for SRB1 and SRB2 and avoids applying the default SRB configuration for SRB4 or SRBx. The various actions in method 400 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 4 may be omitted.

[0274] FIG. 5 depicts a process for applying default SRB during LTM cell switch. While performing LTM cell switch (as in section 5.3.5.18.6 of TS 38.331), the UE 100 applies the default SRB configuration for SRB3 and avoids applying the default SRB configuration for SRB5.

[0275] In step 501, the UE 100 is configured with SRB3 and SRB5. At step 502, the UE 100 receives LTM configuration for SCG (wherein the order of steps 501 and 502 are interchangeable). At step 503, the UE 100 performs LTM cell switch (as in section 5.3.5.18.6 of TS 38.331). While performing LTM cell switch, at step 504, the UE 100 applies the default SRB configuration for SRB3 and avoids applying the default SRB configuration for SRB5. The various actions in method 500 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 5 may be omitted.

[0276] Without this embodiment herein, there will be a need to define a standardized default SRB configuration for sending QoE measurements and AI / ML related data, which will in turn increase the implementation complexity of devices and the networks. The embodiments disclosed herein enable the UE 100 to apply SRB configuration completely based on the network configuration and allows the full configuration of the SRB related parameters.

[0277] FIG. 6 depicts a method for Lower-layer Triggered Mobility (LTM) cell switch execution in a wireless network. In step 601, the UE 100 is configured for dual connectivity and has a Primary secondary cell (PSCell). In step 602, the UE 100 receives LTM configuration for the SCG LTM cell switch, and the LTM configuration is associated with the MCG, and also has configuration for the MCG. The received configuration can be associated with the MCG. On LTM cell switch being triggered on a SCG, in step 603, the UE 100 releases the first set of configurations associated with the MCG. The first set of configurations comprises dedicated and common radio configurations which have not been received via SRB1 within a mrdc-SecondaryCellGroup, and dedicated and common radio configurations which have not been received via SRB3. On LTM cell switch being triggered on a SCG, in step 604, the UE 100 retains the second set of configurations associated with the MCG. The second set of configurations comprises a radio bearer configuration, a C-RNTI, at least one AS security configuration associated with a master key; a logged measurement configuration; and ServingCellConfigCommon of a PCell. The various actions in method 600 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 6 may be omitted.

[0278] FIG. 7 is a block diagram of a Master Node (MN). While configuring the UE for (inter-CU) MCG LTM with intra-SN PSCell change, a Master Node (MN) may perform a MR-DC release and add procedure. If the MN includes the mrdc-SecondaryCellGroup in MCG LTM configuration (RRCReconfiguration message which will be applied during MCG LTM cell switch), the MN may also include the mrdc-ReleaseAndAdd, wherein the MN can set the mrdc-ReleaseAndAdd as true; i.e., if the RRCReconfiguration message which will be applied during MCG LTM cell switch includes MRDC-SecondaryCellGroupConfig, the RRCReconfiguration message will also include mrdc-ReleaseAndAdd, which is set to true in the RRCReconfiguration message. This will allow the network to configure the PSCellChange during MCG LTM without the UE modifications. 'MR-DC release and add' is a network based solution for applying the SCG configuration irrespective of the current configuration of the PSCell. 'MR-DC release and add' may internally trigger the release of the SCG configuration (both common and dedicated configurations), thus minimizing the implementation complexity.

[0279] The MN 700 may perform wireless communication with at least one terminal located within the area of the MN 700 through a wireless channel. The MN 700 may perform communication with a node or an entity of a network through wired or wireless communication.

[0280] Referring to FIG. 7, the MN 700 may include at least one transceiver (hereinafter, referred to as simply "transceiver") 701, at least one processor (hereinafter, referred to as simply "processor") 702, and at least one memory (hereinafter, referred to as simply "memory") 703. According to at least one or a combination of methods corresponding to the embodiments described in the present disclosure, the transceiver 701, the processor 702, and the memory 703 of the MN 700 may operate. However, components of the MN 700 are not limited to the exemplary components illustrated in FIG. 7. In another embodiment, the MN 700 may further include additional components in addition to the above-mentioned components, or some components may be omitted. Further, in some embodiments, any combination of the transceiver 701, the processor 702, or the memory 703 may be integrated in the form of one component.

[0281] The transceiver 701 may be a communication circuit or communication circuitry that enables the MN 700 to perform wireless communication with a node or an entity of a network. For example, the transceiver 701 may enable the MN 700 to transmit or receive a signal to or from the UE 100 through cellular communication, or to transmit or receive a signal to or from another network entity through wireless communication. For example, the transceiver 701 may support various cellular communication technologies including 3rd generation (3G), 4th generation (4G), long term evolution (LTE), 5th generation (5G) NR, 6th generation (6G), and various cellular wireless communication technologies supported by the transceiver (701) may include all subsequent generations of evolved wireless communications. According to an embodiment, the transceiver 701 may include various circuit structures used to transmit or receive signals to or from a UE through a wireless channel. The signals may include control information and data. For example, the transceiver 701 may include a radio frequency (RF) transmitter for up-converting and amplifying the frequency of a transmitted signal and an RF receiver for low-noise-amplifying a received signal and down-converting the frequency thereof. The transceiver 701 may output a signal received through a wireless channel to the processor 702 and may transmit, through a wireless channel, a signal output from the processor 702.

[0282] Meanwhile, according to an embodiment of the present disclosure, the MN 700 may perform communication with a node or an entity of a network through wired or wireless communication. For example, the MN 700 may perform wired or wireless communication with an adjacent BS, or a node or an entity of a core network through a backhaul network. Although not illustrated in FIG. 7, when the MN 700 performs wired communication, the MN 700 may further include a separate network interface for wired communication in addition to the transceiver 701. The network interface may be referred to as network interface circuitry or communication interface circuitry.

[0283] The processor 702 may control general operations of the MN 700 according to embodiments of the disclosure. The processor 702 may be implemented by one or more integrated circuit (or circuitry) (IC) chips and may execute various data processing. The processor 702 may include at least one electric circuit, and may execute instructions (or a program, codes, data, etc.) stored in the memory 703, individually, collectively or in any combination thereof. Further, the processor 702 may include a single-core processor or multi-core processor and may include a processor assembly including a plurality of processing circuits (circuitry) according to a specific implementation scheme.

[0284] The processor 702 may be electrically, operatively, and / or communicatively coupled to the transceiver 701 to control the transceiver 701.

[0285] The processor 702 may include at least one processor (or processing circuitry), and the at least one processor may perform the following operations individually, collectively or in any combination thereof. In a specific embodiment, at least a part of the processor 702 may be included in one chip and the other part of the processor 702 may be included in another chip. Otherwise, at least one processor may be included in another component, for example, the transceiver 701 or the memory 703.

[0286] The processor 702 may perform or control or cause an operation of the MN 700 for executing at least one or a combination of methods according to embodiments of the disclosure. For example, the processor 702 may control operations of the MN 700 for generating and transmitting a downlink signal to a UE or processing an uplink signal received from a UE. Otherwise, the MN 700 may transmit or receive a signal to or from a neighboring BS, transfer a signal received from a UE to an upper node of the network, or transmit a signal transferred from an upper node of the network to a UE. To this end, the processor 702 may execute a computer program, codes, or instructions stored in the memory 703, so as to control other components of the MN 700 to enable execution of various operations.

[0287] The memory 703 corresponds to a hardware storage device capable of temporarily or permanently storing information and may include one or more storage media. For example, the memory 703 may include a memory assembly including one or more storage media. For example, the one or more storage media may include permanent memory, such as a hard drive, flash memory, or read-only memory (ROM), semipermanent memory, such as random access memory (RAM), cache memory, or a combination thereof.

[0288] The memory 703 may be electrically, operatively, and / or communicatively coupled to the processor 702 and may be accessed by the processor 702.

[0289] The memory 703 may store a computer program, codes, or instructions executable by the processor 702. According to an embodiment, a computer program, codes, or instructions executable by the processor 702 may be either stored in a single memory device or separated and stored in a distributed manner in two or more memory devices. By executing the instructions stored in the memory 703, the processor 702 may perform various functions according to an embodiment of the disclosure.

[0290] According to an embodiment of the disclosure, operations of the MN 700 may be caused to be performed based on execution of instructions (or a computer program or codes) stored in the memory 703 by at least one processor (or processing circuitry) configured to execute the same individually, collectively, or in any combination thereof, based on processing circuitry that is not configured to execute instructions, and / or based on components of processing circuitry that is not configured to execute instructions.

[0291] While configuring the UE for LTM which triggered on the MCG which sets up the SCG, the processor 702 can perform Multi-Radio Dual Connectivity (MR-DC) release and add procedure. If the RRCReconfiguration message will be applied by the UE during Master Cell Group (MCG) LTM cell switch, and the RRCReconfiguration message includes an mrdc-SecondaryCellGroup set to setup, the processor 702 can include mrdc-ReleaseAndAdd in a RRCReconfiguration message.

[0292] FIG. 8 depicts a method for Lower-layer Triggered Mobility (LTM) cell switch execution in a wireless network. In step 801, the MN 700 configures the UE 100 to perform MR-DC release and add procedure, while configuring the UE for LTM which triggered on the MCG which sets up the SCG. In step 802, the MN 700 performs the MR-DC release and add procedure. If the RRCReconfiguration message will be applied by the UE during Master Cell Group (MCG) LTM cell switch, and the RRCReconfiguration message includes an mrdc-SecondaryCellGroup set to setup, in step 803, the MN 700 includes mrdc-ReleaseAndAdd in a RRCReconfiguration message. The various actions in method 800 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 8 may be omitted.

[0293] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The elements include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.

[0294] The embodiments disclosed herein describe methods and systems for managing a Lower-Layered Triggered Mobility (LTM) Cell Switch, wherein the LTM Cell Switch is triggered by a Master Cell Group (MCG) in a wireless communication network. Therefore, it is understood that the scope of the protection is extended to such a program and in addition to a computer readable means having a message therein, such computer readable storage means contain program code means for implementation of one or more steps of the method, when the program runs on a server or mobile device or any suitable programmable device. The method is implemented in at least one embodiment through or together with a software program written in e.g., Very high speed integrated circuit Hardware Description Language (VHDL) another programming language or implemented by one or more VHDL or several software modules being executed on at least one hardware device. The hardware device can be any kind of portable device that can be programmed. The device may also include means which could be e.g., hardware means like e.g., an ASIC, or a combination of hardware and software means, e.g., an ASIC and an FPGA, or at least one microprocessor and at least one memory with software modules located therein. The method embodiments described herein could be implemented partly in hardware and partly in software. Alternatively, the invention may be implemented on different hardware devices, e.g., using a plurality of CPUs.

[0295] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments and examples, those skilled in the art will recognize that the embodiments and examples disclosed herein can be practised with modification within the scope of the embodiments as described herein.

Claims

1.A method, performed by a user equipment (UE) in a communication system, the method comprising:from a base station, receiving radio resource control (RRC) reconfiguration message including Lower-layerd Triggered Mobility (LTM) configuration related to a LTM cell switch; andreleasing configurations, in case that the LTM cell switch is triggerd on a secondary cell group (SCG) and the LTM configuration related to the LTM cell switch is associated with a master cell group (MCG).2.The method of claim 1,wherein the configurations are released in case that the LTM cell switch is triggerd on the MCG.3.The method of claim 1,wherein the configurations are neither been received via signalling radio bearer 1 (SRB1) within mrdc-SecondaryCellGroup, nor via signalling radio bearer 3 (SRB3).4.The method of claim 3,wherein at least one of:radio bearer configuration,logicalChannelIdentity and logicalChannelIdentityExt of radio link control (RLC) bearers configured in RLC-BearerConfig and associated RLC entities, state variables, buffers, and timers, except for triggering the associated RLC entities to reset variable RETX_COUNT its initial value,bh-LogicalChannelIdentity of back haul (BH) RLC channels configured in BH-RLC-ChannelConfig and the associated RLC entities, state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value,UE variables VarLTM-ServingCellNoResetID and VarLTM-ServingCellUE-MeasuredTA-ID,ltm-Config,master cell group cell radio network temporary identifier (MCG C-RNTI),access stratum (AS) security configurations associated with master key,logged measurement configuration, orServingCellConfigCommon of a primary cell (Pcell)are not released.5.A method, performed by a base station (BS) in a communication system, the method comprising:to a user equipment (UE), transmitting radio resource control (RRC) reconfiguration message including Lower-layerd Triggered Mobility (LTM) configuration related to a LTM cell switch,wherein configurations are released, in case that the LTM cell switch is triggerd on a secondary cell group (SCG) and the LTM configuration related to the LTM cell switch is associated with a master cell group (MCG).6.The method of claim 5,wherein the configurations are released in case that the LTM cell switch is triggerd on the MCG.7.The method of claim 5,wherein the configurations are neither been received via signalling radio bearer 1 (SRB1) within mrdc-SecondaryCellGroup, nor via signalling radio bearer 3 (SRB3).8.The method of claim 7,wherein at least one of:radio bearer configuration,logicalChannelIdentity and logicalChannelIdentityExt of radio link control (RLC) bearers configured in RLC-BearerConfig and associated RLC entities, state variables, buffers, and timers, except for triggering the associated RLC entities to reset variable RETX_COUNT its initial value,bh-LogicalChannelIdentity of back haul (BH) RLC channels configured in BH-RLC-ChannelConfig and the associated RLC entities, state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value,UE variables VarLTM-ServingCellNoResetID and VarLTM-ServingCellUE-MeasuredTA-ID,ltm-Config,master cell group cell radio network temporary identifier (MCG C-RNTI),access stratum (AS) security configurations associated with master key,logged measurement configuration, orServingCellConfigCommon of a primary cell (Pcell)are not released.9.A user equipment (UE) in a wireless communication system, comprising:a transceiver; anda controller coupled to the transceiver and configured to:from a base station, receive radio resource control (RRC) reconfiguration message including Lower-layerd Triggered Mobility (LTM) configuration related to a LTM cell switch; andrelease configurations, in case that the LTM cell switch is triggerd on a secondary cell group (SCG) and the LTM configuration related to the LTM cell switch is associated with a master cell group (MCG).10.The UE of claim 9,wherein the configurations are released in case that the LTM cell switch is triggerd on the MCG.11.The UE of claim 9,wherein the configurations are neither been received via signalling radio bearer 1 (SRB1) within mrdc-SecondaryCellGroup, nor via signalling radio bearer 3 (SRB3).12.The UE of claim 11,wherein at least one of:radio bearer configuration,logicalChannelIdentity and logicalChannelIdentityExt of radio link control (RLC) bearers configured in RLC-BearerConfig and associated RLC entities, state variables, buffers, and timers, except for triggering the associated RLC entities to reset variable RETX_COUNT its initial value,bh-LogicalChannelIdentity of back haul (BH) RLC channels configured in BH-RLC-ChannelConfig and the associated RLC entities, state variables, buffers, and timers, except for triggering the associated RLC entities to reset the variable RETX_COUNT its initial value,UE variables VarLTM-ServingCellNoResetID and VarLTM-ServingCellUE-MeasuredTA-ID,ltm-Config,master cell group cell radio network temporary identifier (MCG C-RNTI),access stratum (AS) security configurations associated with master key,logged measurement configuration, orServingCellConfigCommon of a primary cell (Pcell)are not released.13.A base station (BS) in a wireless communication system, comprising:a transceiver; anda controller coupled to the transceiver and configured to:to a user equipment (UE), transmit radio resource control (RRC) reconfiguration message including Lower-layerd Triggered Mobility (LTM) configuration related to a LTM cell switch,wherein configurations are released, in case that the LTM cell switch is triggerd on a secondary cell group (SCG) and the LTM configuration related to the LTM cell switch is associated with a master cell group (MCG).14.The BS of claim 13,wherein the configurations are released in case that the LTM cell switch is triggerd on the MCG.15.The BS of claim 13,wherein the configurations are neither been received via signalling radio bearer 1 (SRB1) within mrdc-SecondaryCellGroup, nor via signalling radio bearer 3 (SRB3).

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