Methods and apparatus for handling a radio link failure (RLF) in a wireless communication network

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Embodiments disclosed herein relate to a wireless communication network, and there is a need for effective and efficient methods and systems for handling a radio link failure (RLF) recovery in the wireless communication network.

Description

METHODS AND APPARATUS FOR HANDLING A RADIO LINK FAILURE (RLF) IN A WIRELESS COMMUNICATION NETWORK

[0001] Embodiments disclosed herein relate to a wireless communication network, and more particularly to methods and systems for handling a radio link failure (RLF) recovery in the 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] 5th generation (5G) or new radio (NR) mobile communications is recently gathering increased momentum with all the worldwide technical activities on the various candidate technologies from industry and academia. The candidate enablers for the 5G / NR mobile communications include massive antenna technologies, from legacy cellular frequency bands up to high frequencies, to provide beamforming gain and support increased capacity, new waveform (e.g., a new radio access technology (RAT)) to flexibly accommodate various services / applications with different requirements, new multiple access schemes to support massive connections, and so on.

[0009] In wireless technologies like Fifth Generation (5G) New Radio (NR), devices can move across different cells. Mobility is performed using a procedure called cell reselection in RRC_IDLE mode. Until NR Release 17, mobility in RRC_CONNECTED mode was managed by a procedure called handover. Network controlled mobility applies to a User Equipment (UE) in RRC_CONNECTED mode, requiring explicit Radio Resource Control (RRC) signaling triggered by a gNB (or gNodeB) in the NR. The Handover in the NR consists of three steps: handover preparation, handover execution, and handover completion. The gNB may configure the UE to report measurements and based on the reported measurements, or based on the network topology, the gNB will send a RRC Reconfiguration message to handover the UE to another cell, referred to as the target cell, from the source cell. The UE accesses the target cell and sends the RRC Reconfiguration complete message.

[0010] An alternative approach introduced in 3GPP NR Release 16, wherein the gNB may configure the UE with the execution conditions for triggering the handover. Once the execution conditions are satisfied, the UE may move to the target cell and send the RRC Reconfiguration complete. 3GPP introduced a new handover method called DAPS handover in Release 16. In all these methods, the UE performs handover by sending layer 3 (RRC) messages, leading to considerable signaling overhead and latency issues. We can refer to the handover, and conditional handover (CHO) as layer 3 mobility. During handover, the UE may be configured to apply full configuration during a L3 handover, and if configured, the UE applies full configuration as described in section 5.3.5.11 of TS 38.331. In case of dual connectivity. The patent application refer to the handover, and conditional handover (CHO) as layer 3 mobility. The 3gpp release 18 also introduced Lower layers (L1 / L2 layers) Triggered Mobility, also known as LTM.

[0011] NG-RAN supports Multi-Radio Dual Connectivity (MR-DC) operation, whereby a User Equipment (UE) in RRC_CONNECTED mode is configured to utilize radio resources provided by two distinct schedulers located in two different NG-RAN nodes connected via a non-ideal backhaul. One node provides NR access, while the other provides either Evolved UMTS Terrestrial Radio Access (E-UTRA) or NR access. One node act as the Master Node (MN), and the other acts as the Secondary Node (SN). The MN and SN are connected via a network interface, and at least the MN is connected to the core network.

[0012] NG-RAN supports NG-RAN E-UTRA-NR Dual Connectivity (NGEN-DC), wherein a UE is connected to one ng-eNB (an E-UTRA base station capable of connecting to a 5G core) that acts as the MN and one gNB (5G base station) that acts as the SN. NG-RAN supports NR-E-UTRA Dual Connectivity (NE-DC), where the UE is connected to one gNB acting as the MN and one ng-eNB acting as the SN. The MN may move the SCG (Secondary Cell Group) to different states such as deactivated or activated. When carrier aggregation is supported, the secondary cells may also be moved between deactivated and activated states. When a radio link failure occurs in the SCG, the UE sends an RRC message, SCGFailureInformation.

[0013] A Primary SCG Cell (PSCell) change can occur due to mobility and may or may not involve a Secondary Node Change (SN change). The Secondary Node Change procedure can be initiated by either the MN or SN and is used to transfer the UE context from a source SN to a target SN while updating the SCG configuration in the UE.

[0014] A Conditional PSCell Change (CPC) is defined as a PSCell change executed by the UE when specific execution conditions are met. The UE may be configured with execution conditions, and upon meeting them, the RRC message (e.g., RRC Reconfiguration) is executed for one or more candidate cells. The UE begins evaluating the execution conditions upon receiving the CPC configuration and stops evaluating once a PSCell change is triggered. Both intra-SN CPC without MN involvement and inter-SN CPC initiated by either the MN or SN are supported. The MN adds PSCell during a PSCell addition procedure. A PSCell addition procedure that is executed only when PSCell addition conditions are met is referred to as Conditional PSCell Addition (CPA).

[0015] UE may perform PSCellChange or Conditional PSCellChange. In the context of dual connectivity, we can refer PSCellChange or Conditional PSCellChange also as layer 3 mobility. i.e. handover, conditional handover, PSCellChange,Conditional PSCellChange etc. refers to L3 mobility. PSCellChange or Conditional PSCellChange can be referred to as SCG layer 3 mobility and the handover and CHO as MCG layer 3 mobility in the context of dual connectivity. A UE may be configured to apply a conditional configuration after radio link failure using a flag by the network apparatus. In NR, network configures UE with attemptCondReconfig flag. If this flag is configured, the UE will perform conditional reconfiguration after selecting a cell after radio link failure, if selected cell is a target candidate cell and it is the first cell selection after failure.

[0016] Third Generation Partnership Project (3GPP) Release 18 is considering Lower Layers (L1 / L2 layers) Triggered Mobility (LTM), known as LTM to solve the problem related to latency, signaling overhead etc., associated with layer 3 mobility. As per 3GPP, LTM is to enable a serving cell change via L1 / L2 signaling, to reduce the latency, overhead and interruption time. Network (gNB) may configure the UE with multiple candidate cells to allow fast application of configurations for candidate cells. Network may further send Medium Access Control-Control Element (MAC CE) or L1 signaling to dynamically switch the UE from a source cell to one of the configured candidate cells. Further, the LTM can be triggered based on L1 measurements rather than L3 measurements.

[0017] The 3GPP proposes to perform LTM, without reset of lower layers like MAC to avoid data loss and to reduce the additional delay of data recovery wherever it is possible.

[0018] The gNB CU may provide LTMCandidateConfiguration, i.e. configure LTM candidate cells through one RRCReconfiguration message for a candidate target cell. The gNB may further release or modify the candidate configurations. A UE may store the LTM configuration of other candidate cells even after moving to a candidate cell through LTM. The gNB CU may provide the UE with configuration for performing LTM measurements for different candidate frequencies and candidate cells and reporting based on the performed LTM measurements. The gNB may further release or modify the candidate configurations. The UE may store the LTM configuration of other candidate cells even after moving to a candidate cell through LTM. The gNB also may provide the UE with configuration for performing LTM measurements for different candidate frequencies and candidate cells and reporting based on the performed LTM measurements. The 3GPP supports subsequent LTM, i.e. after one LTM candidate cell becomes a source cell due to LTM, the UE may store LTM candidate configuration and continue to report LTM measurements (i.e., L1 measurements for LTM) and the new serving cell may send LTM cell switch command to the UE and the UE performs LTM, and such LTM is called as the subsequent LTM. A UE may be configured to apply a LTM candidate configuration after radio link failure using a flag by the network apparatus. In NR, network configures UE with attemptLTM-Switch flag. If this flag is configured, the UE will execute an LTM cell switch after selecting a cell after radio link failure, if selected cell is a target candidate cell and it is the first cell selection after failure.

[0019] The UE performs the L1 measurements on the source cell and candidate cell to report L1 measurements through CSI reports to the gNB DU of the source cell. The gNB DU may send a MAC CE (for e.g. LTM MAC CE or cell switch MAC CE) asking the UE to switch to another cell which is a LTM candidate cell. The UE may perform random access during LTM cell switch, or the cell switch may be RACH less. The CellSwitch may be guarded by a timer (referred as T3xx).

[0020] The UE may be requested to perform random access on a candidate cell before the cell switch, so that the network can calculate the timing advance before the cell switch and inform the UE either through a random-access response or within the MAC CE which is send for the cell switch. The gNB may configure the UE to perform random access towards one or more LTM candidate cells for receiving the Timing Advance (TA) before the cell switch is performed (known as Early TA or Early Sync TA or TA for Early Sync). Random access performed on LTM candidate cells for the timing advance reception is known as random access for early TA. The gNB sends a Physical Downlink Control Channel (PDCCH) order to initiate Random Access Channel (RACH) for TA measurement for candidate cells. The UE receives PDCCH order from the serving cell. Upon reception of this PDCCH order, UE initiates RACH for TA measurement for candidate cells on the one or more candidate cell. UE sends RACH preamble to the candidate cells and receives the Timing Advance (TA) value from the candidate cell. TA for candidate cells may be received from the source cell also. Normally, TA will be received in the random-access response, but it may be also received through a MAC CE. If source DU indicates the UE to retransmit the RACH for early TA, UE retransmits the same. gNB may also send PDCCH order to retransmit RACH for TA measurement (also known as RACH for early sync).

[0021] In conventional methods, the UE does reset MAC and handle the configuration when configured with attemptCondReconfig or attemptLTM-Switch is not disclosed. Therefore, handling of UE with the successPSCell-Config (i.e. configuration for the UE to report the successful PSCell change or addition information to the network) when configured with attemptCondReconfig or attemptLTM-Switch is not disclosed. As a result, the UE and the network will be unsynchronized with respect to successPSCell-Config. The reporting of the UE about the capabilities for PDCCH ordered RACH is not disclosed.

[0022] Further, a 5G NR (new radio) radio access network also known as NG-RAN (Next Generation Radio Network) comprises a number of NR base stations (i.e., gNBs). The gNBs can be connected to each other through a Xn interface, and will be connected to various core network elements like AMF (Access and Mobility Management Function), UPF (User Plane Function) etc. Further, the gNBs can be divided into two physical entities; a CU (Centralized Unit) and a DU (Distributed Unit). The CU provides support for the higher layers of the protocol stack such as SDAP (Session Data Application Protocol), PDCP (Packet Data Convergence Protocol) and RRC (Radio Resource Control). The DU provides support for the lower layers of the protocol stack such as RLC (Radio Link Control), MAC (Medium Access Control) and Physical layer. Each gNB can have multiple cells serving many UEs (User Equipment). There are a large number of algorithms and configuration parameters used in NG-RAN. Especially, it is a very difficult task to identify the most optimal radio parameters and operators used to resort to manual techniques like drive tests to identify the optimal parameters. However, such manual parameter tuning is a costly operation since it depends on a lot of factors like the number of users, number of neighbors, maximum throughput in the cell, average throughput in the cell etc. Further, whenever a neighboring gNB is installed or a new service is introduced, many of these manual operations need to be repeated.

[0023] To resolve this problem, 3GPP has introduced Self-Organizing Networks (SON) techniques in wireless technologies like NR. SON was first introduced in 3GPP Release 9, in LTE. SON solutions can be divided into three categories: Self-Configuration, Self-Optimization and Self-Healing. The SON architecture can be a centralized, distributed or a hybrid solution. Mobility Robustness Optimization (MRO) is a SON technique which is used to optimize various parameters related to mobility.

[0024] According to 3GPP specifications like TS 38.300 V17.3.0, mobility robustness optimization aims at detecting and enabling correction of following problems:

[0025] - Connection failure due to intra-system or inter-system mobility;

[0026] - Inter-system Unnecessary HO (too early inter-system HO from NR to E-UTRAN with no radio link failure);

[0027] - Inter-system HO ping-pong.

[0028] The Mobility Robustness Optimization (MRO) provides a means to distinguish the above problems from NR coverage related problems and other problems, not related to mobility.

[0029] One of the functions of Mobility Robustness Optimization is to detect a sub-optimal successful handover event. The aim of MRO is to identify underlying conditions during successful ordinary handovers, successful DAPS handovers, or successful Conditional handovers. For analysis of successful handover, the UE supports Successful Handover Report based on configuration by network (for e.g., through IE successHO-Config as defined in 3gpp Technical Specification TS 38.331 in NR), if received, and makes the Successful Handover Report (SHR)available to the network. Upon retrieval of a Successful Handover Report, the receiving node may analyse whether its mobility configuration needs adjustment. Similarly, for dual connectivity, the UE may be configured to report successful PSCell Change or Addition Information (SPR) as described in 3gpp specifications such as TS 38.331.

[0030] Network configures the UE for successful handover reporting. In NR, gNB configures UE for successful handover reporting through OtherConfig in RRCReconfiguration. OtherConfig-v1700 ::=

[0031] SEQUENCE {

[0032] successHO-Config-r17 SetupRelease {SuccessHO-Config-r17} OPTIONAL, -- Need M

[0033] <only relevant parameter shown>

[0034] }

[0035] The gNB also may configure the UE for successful handover reporting for inter-RAT handover and through MobilityFromNRCommand as follows:

[0036] MobilityFromNRCommand-v1800-IEs ::= SEQUENCE {

[0037] successHO-Config-r18 SetupRelease {SuccessHO-Config-r17} OPTIONAL,

[0038] nonCriticalExtension SEQUENCE {} OPTIONAL

[0039] }

[0040] The SuccessHO-Config (Configuration for the UE to report the successful handover information to the network.) includes some thresholds and may also include some conditions which the UE evaluates at the time of handover. Based on the evaluation, the UE logs Successful Handover report.

[0041] In NR, SuccessHO-Config is defined as follows:

[0042] SuccessHO-Config-r17 ::= SEQUENCE {

[0043] thresholdPercentageT304-r17 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0044] thresholdPercentageT310-r17 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0045] thresholdPercentageT312-r17 ENUMERATED {p20, p40, p60, p80, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0046] sourceDAPS-FailureReporting-r17 ENUMERATED {true} OPTIONAL, --Need R

[0047] ...

[0048] }

[0049] There are different conditions when the UE logs SHR, based on the thresholds provided.

[0050] If the network configures the UE with the thresholdPercentageT310 and the ratio between the value of the elapsed time of the timer T310 and the configured value of the timer T310, is greater than the thresholdPercentageT310, UE logs SHR. If the network configures the UE with the thresholdPercentageT312 and the ratio between the value of the elapsed time of the timer T312 and the configured value of the timer T312, is greater than the thresholdPercentageT312, UE logs SHR. If the network configures the UE with the thresholdPercentageT304 and the ratio between the value of the elapsed time of the timer T304 and the configured value of the timer T304, is greater than the thresholdPercentageT304, UE logs SHR.

[0051] UE reports logged SHR to the network based on the request from the network.

[0052] For SCG mobility optimisation, network may configure the UE with successPSCell configuration (SuccessPSCell-Config) to log and report SPR.

[0053] SuccessPSCell-Config-r18 ::= SEQUENCE {

[0054] thresholdPercentageT304-SCG-r18 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0055] thresholdPercentageT310-SCG-r18 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0056] thresholdPercentageT312-SCG-r18 ENUMERATED {p20, p40, p60, p80, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0057] ...

[0058] }

[0059] There are different conditions when the UE logs SPR, based on the thresholds provided.

[0060] If the network configures the UE with the thresholdPercentageT310-SCG and the ratio between the value of the elapsed time of the timer T310 and the configured value of the timer T310, is greater than the thresholdPercentageT310-SCG, UE logs SPR. If the network configures the UE with the thresholdPercentageT312-SCG and the ratio between the value of the elapsed time of the timer T312 and the configured value of the timer T312, is greater than the thresholdPercentageT312-SCG, UE logs SPR. If the network configures the UE with the thresholdPercentageT304 and the ratio between the value of the elapsed time of the timer T304 and the configured value of the timer T304, is greater than the thresholdPercentageT304-SCG, UE logs SPR.

[0061] The UE reports logged SPR to the network based on the request from the network.

[0062] According to NR specification TS 38.331, the parameters are defined as below:

[0063]

[0064]

[0065] In NR, R18, the evaluation of successful handover involves the various steps in TS 38.331 V18.0.0 5.3.5.9 and 5.4.3.3.

[0066] In NR, the evaluation of successful handover is performed according to the below.

[0067] 1> set the content of the RRCReconfigurationComplete message as follows:

[0068] 2> if the RRCReconfiguration includes the reconfigurationWithSync in spCellConfig of an MCG:

[0069] 3> if the UE was configured with successHO-Config when connected to the source PCell; and

[0070] 3> if the applied RRCReconfiguration is not due to a conditional reconfiguration execution upon cell selection performed while timer T311 was running, as defined in 5.3.7.3:

[0071] 4> perform the actions for the successful handover report determination as specified in clause 5.7.10.6, upon successfully completing the Random Access procedure triggered for the reconfigurationWithSync in spCellConfig of the MCG;

[0072] 5.4.3.4 Successful completion of the mobility from NR

[0073] 1> if the UE was configured with successHO-Config when connected to the source PCell and the targetRAT-Type is set to eutra:

[0074] 2> perform the actions for the successful handover report determination as specified in clause 5.7.10.6.

[0075] If the conditions for successful handover configuration are satisfied, UE logs a successful handover report (SHR). In NR SHR is defined in TS 38.331.

[0076] The UE indicates the availability of SHR in RRC complete messages. In NR, the messages can be RRCSetupComplete, RRCResumeComplete and RRCReconfigurationComplete. Further, the UE may receive a request to send SHR and report the SHR to the network.

[0077] In NR, the request to include SHR is sent in a UEInformationRequest message, and the UE sends the SHR to gNB through a UEInformationResponse message as described in NR TS 38.331.

[0078] The current methods for Successful Handover configuration do not allow the configuration of T310 and T312 thresholds in successful handover configuration (such as SuccessHO-Config in NR) at the time of handover. Similarly, for successful PSCellChange, configuration of T310 and T312 thresholds in Success PSCell Configuration (such as successPSCell-Config in NR) at the time of PSCellChange is not possible when the PSCellChange is directly send by the SN without MN interaction.

[0079] The 3GPP V18.0.0 version of TS 38.331, TS 38.321, TS 38.300 and TS 38.304 can be considered as relevant background. The 3GPP specifications such as TS38.300, TS38.331, TS 38.321 v18.0.0 can also be considered as relevant background.

[0080] Hence, there is a need in the art for solutions which will overcome the above-mentioned drawback(s), among others.

[0081] The principal object of the embodiments herein is to disclose methods and systems for handling a radio link failure (RLF) in a wireless communication network.

[0082] Further object of embodiments herein is to discover methods and systems for configuring at least one threshold parameter in the wireless communication network.

[0083] Another object of embodiments herein is to provide self-optimization for the mobility in dual connectivity of a user equipment (UE) in wireless communication network.

[0084] Further object of embodiments herein is to provide T310 and T312 threshold for optimization during the handover in dual connectivity in the wireless communication network.

[0085] Another object of embodiments herein is to provide that the UE keeping the SPR configuration when attemptCondReconfig and attemptLTM-Switch are configured.

[0086] Another object of embodiments herein is to provide that the UE releasing the above configuration when recovery according to attemptCondReconfig and attemptLTM-Switch fails.

[0087] Another object of embodiments herein is to provide a method for handling SPR configuration during RRCReestablishment when the UE is configured for CHO based recovery or LTM based recovery,

[0088] Another object of embodiments herein is to allow the network entity to configure SPR configuration over SRB3.

[0089] Another object of embodiments herein is to provide a network entity that configures the UE with the T310-SCG threshold (thresholdPercentageT310-SCG-r18) and T312-SCG threshold (thresholdPercentageT312-SCG-r18) from the source PSCell before the ReconfigurationSync for the PSCellChange send to the UE when the RRCReconfiguration including ReconfigurationWithSync is send over SRB3.

[0090] In line with development of the communication systems, there is a need for methods and systems for handling a radio link failure.

[0091] The technical subjects pursued in the disclosure may not be limited to the above mentioned technical subjects, and other technical subjects which are not mentioned may be clearly understood, through the following descriptions, by those skilled in the art to which the disclosure pertains.

[0092] The embodiment discloses a method for handling a radio link failure (RLF) in a wireless communication network. The method includes determining, by a user equipment (UE), whether at least one parameter related to at least one of: a conditional re-configuration, and a mobility switch attempt is configured, while initiating a RRC Reestablishment procedure. The method includes performing, by the UE, one of: retaining successPSCell configuration configured by a Primary Secondary Cell Group Cell (PSCell), on determining that the at least one parameter related to the at least one of: the conditional re-configuration, and the mobility switch attempt is configured; and releasing successPSCell configuration configured by the PSCell, on determining that the at least one parameter related to at least one of: the conditional re-configuration, and the mobility switch attempt is not configured.

[0093] Embodiments disclose methods for handling a radio link failure (RLF) in a wireless communication network. The method includes determining, whether at least one parameter related to at least one of: a conditional re-configuration, and a mobility switch attempt is configured, while initiating a RRC Reestablishment procedure. The method included performing, by the UE, one of: retaining successPSCell configuration configured by a Primary Secondary Cell Group Cell (PSCell), on determining that the at least one parameter related to the at least one of: the conditional re-configuration, and the mobility switch attempt is configured, and releasing successPSCell configuration configured by the PSCell, on determining that the at least one parameter related to at least one of: the conditional re-configuration, and the mobility switch attempt is not configured.

[0094] The embodiments disclose a method for configuring at least one threshold parameter in a wireless communication network. The method includes configuring, by a network entity, a UE to report at least one of a successful PSCell change and an additional information to a network with a successPSCell-Config from a source Primary Secondary Cell (PSCell). The method includes configuring, by the network entity, the UE to perform PSCell change through a Signalling Radio Bearer 3 (SRB3) in a RRC Reconfiguration message.

[0095] The embodiments disclose a User Equipment, comprising: a processor; a memory; and a radio link failure (RLF) controller, coupled with the processor and the memory. The RLF controller configured to determine whether at least one parameter related to at least one of: a conditional re-configuration, and a mobility switch attempt is configured, while initiating a RRC Reestablishment procedure. The RLF controller performs one of: retain successPSCell configuration configured by a Primary Secondary Cell Group Cell (PSCell), on determining that the at least one parameter related to the at least one of: the conditional re-configuration, and the mobility switch attempt is configured. The RLF controller releases successPSCell configuration configured by the PSCell, on determining that the at least one parameter related to at least one of: the conditional re-configuration, and the mobility switch attempt is not configured.

[0096] The embodiments disclose a network entity, comprising: a processor; a memory; and a threshold configuring controller, coupled with the processor and the memory. The threshold configuring controller configures a UE to report at least one of a successful PSCell change and an additional information to a network with a successPSCell-Config from a source Primary Secondary Cell (PSCell). The threshold configuring controller configure the UE to perform PSCell change through a Signalling Radio Bearer 3 (SRB3) in a RRC Reconfiguration message.

[0097] 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 scope thereof, and the embodiments herein include all such modifications.

[0098] The present disclosure provides an effective and efficient method for handling a radio link failure. Advantageous effects obtainable from the disclosure may not be limited to the above mentioned effects, and other effects which are not mentioned may be clearly understood, through the following descriptions, by those skilled in the art to which the disclosure pertains.

[0099] 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:

[0100] FIG. 1 is an example diagram illustrating a scenario for handling a radio link failure (RLF) and configuring at least one threshold parameter in a wireless communication network, according to embodiment as disclosed herein;

[0101] FIG. 2 is an example flow diagram for determining a successful handover report (SHR), according to embodiments as disclosed herein;

[0102] FIG. 3 is an example flow diagram for determining the SHR using at least one threshold parameter, according to embodiments as disclosed herein;

[0103] FIG. 4 is an example flow diagram for determining the SPR using at least one threshold parameters, according to embodiments as disclosed herein;

[0104] FIG. 5 is an example diagram depicting the UE performing UE capability reporting for the SHR, according to embodiments as disclosed herein;

[0105] FIG. 6 is an example diagram depicting the interaction of the source gNB and target gNB for performing a handover operation in the SHR configuration, according to embodiments as disclosed herein;

[0106] FIG. 7 is an example flow diagram illustrating a scenario of successPSCell-Config with attempt conditional reconfiguration / LTM, according to embodiments as disclosed herein;

[0107] FIG. 8 is an example flow diagram illustrating the scenario performing cell selection while T311 is running with successPSCell-Config, according to embodiments as disclosed herein;

[0108] FIG. 9 is an example flow diagram illustrating the scenario of performing cell selection while T311 is running with attempt conditional reconfiguration / LTM, according to embodiments as disclosed herein;

[0109] FIG. 10 is an example sequence diagram illustrating the scenario of a UE capability reporting for PDCCH ordered RACH, according to embodiments as disclosed herein;

[0110] FIG. 11 shows various hardware components of the UE, for handling the radio link failure (RLF) in a wireless communication network, according to embodiments as disclosed herein;

[0111] FIG. 12 shows various hardware components of a network entity for configuring at least one threshold parameter in the wireless communication network, according to embodiments as disclosed herein;

[0112] FIG. 13 is a flow chart depicting a method for handling the RLF in the wireless communication network, according to embodiments as disclosed herein; and

[0113] FIG. 14 is a flow chart depicting a method for configuring at least one threshold parameter in the wireless communication network, according to embodiments as disclosed herein.

[0114] 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 can 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] Embodiments herein disclose methods and systems for handling a radio link failure (RLF) in a wireless communication network.

[0121] The proposed method allows a user equipment (UE) to determine whether at least one parameter related to at least one of a conditional re-configuration and a mobility switch attempt is configured while initiating a Radio Resource Control (RRC) Reestablishment procedure.

[0122] The at least one parameter related to the at least one of the conditional re-configurations and the mobility switch attempt comprises a attemptCondReconfig and a attemptLTM-Switch for handling successPSCell configuration configured by a Primary Secondary Cell (PSCell).

[0123] Embodiments herein disclose methods and systems for performing mobility based RLF recovery. The present disclosure provides method for the UE to reset Medium Access Control (MAC) and handle the configuration when configured with attemptCondReconfig or attemptLTM-Switch. Further, the disclosure provides method for the UE to handle successPSCell-Config when configured with attemptCondReconfig or attemptLTM-Switch. The disclosure provides method for the UE to report the capabilities for PDCCH ordered RACH.

[0124] Embodiments herein disclose methods and systems for configuring at least one threshold parameter in the wireless communication network by configuring the UE to report at least one of a successful PSCell change and an additional information to the network with the successPSCell configuration from a source Primary SCG (Secondary Cell Group) Cell. The additional information deals with successful PSCell change and addition information.

[0125] The proposed method discloses at least one threshold parameter comprises a thresholdPercentageT310-SCG-r18 (T310-SCG), and a thresholdPercentageT312-SCG-r18 (T312-SCG).

[0126] The LTM is a procedure in which a gNB receives L1 measurement report(s) from a UE, and on their basis the gNB changes UE's serving cell by a cell switch command signaled via a MAC CE. The cell switch command indicates an LTM candidate cell configuration that the gNB previously prepared and provided to the UE through RRC signalling. 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.

[0127] Network may request the UE to perform early TA acquisition of a candidate cell before a cell switch. The early TA acquisition is triggered by PDCCH order [or through UE-based TA measurement].

[0128] The network indicates in the cell switch command whether the UE shall access the target cell with a RA procedure if a TA value is not provided or with PUSCH transmission using the indicated TA value. For RACH-less LTM, the UE either monitors 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.

[0129] The following principles apply to LTM:

[0130] - The UE doesn't update its security key in LTM.

[0131] - Subsequent LTM is supported.

[0132] LTM supports both intra-gNB-DU and intra-gNB-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:

[0133] - PCell change in non-CA scenario,

[0134] - PCell change in CA scenario,

[0135] - Dual connectivity scenario, at least for the PSCell change without MN involvement case, i.e. intra-SN PSCell change.

[0136] A supervision timer can be used to detect failure of LTM cell switch procedure, wherein LTM procedure fails if the LTM supervision timer expires, upon which the UE initiates RRC connection re-establishment procedure.

[0137] While the UE has stored LTM candidate cell configurations the UE can also execute any L3 handover command sent by the network. It is up to the network to avoid any issue due to a collision between LTM execution and L3 handover execution, e.g. avoiding sending LTM cell switch command and L3 handover command simultaneously.

[0138] Cell switch command is conveyed in a MAC CE, which contains the necessary information to perform the LTM cell switch.

[0139] After RLF is declared, the UE:

[0140] - in case of CHO, for RLF in the source cell:

[0141] - selects a suitable cell and if the selected cell is a CHO candidate and if network configured the UE to try CHO after RLF then the UE attempts CHO execution once, otherwise re-establishment is performed;

[0142] - enters RRC_IDLE if a suitable cell was not found within a certain time after RLF was declared.

[0143] - in case of MCG LTM, for RLF in the source cell:

[0144] - selects a suitable cell and if the selected cell is an LTM candidate cell and if network configured the UE to try LTM after RLF then the UE attempts RACH-based LTM execution once, otherwise re-establishment is performed;

[0145] Similarly, when initial CHO execution attempt fails or HO fails, the UE performs cell selection, and if the selected cell is a CHO candidate and if network configured the UE to try CHO after handover / CHO failure, then the UE attempts CHO execution once, otherwise re-establishment is performed. In the current specifications, UE releases the SPR configuration from PCell and PSCell even when the UE attempts CHO execution.

[0146] When LTM execution attempt triggered by LTM cell switch command MAC CE fails or HO fails, the UE performs cell selection and if the selected cell is an LTM candidate cell and if network configured the UE to try LTM after handover / LTM execution failure, then the UE attempts RACH-based LTM execution once, otherwise re-establishment is performed. In the current specifications, UE releases the SPR configuration from PCell and PSCell even when the UE attempts LTM execution.

[0147] Various steps for the CHO or LTM based recovery is specified as below in TS 38.331

[0148] 5.3.7RRC connection re-establishment

[0149] 5.3.7.2Initiation

[0150] The UE initiates the procedure when one of the conditions such as specified in TS 38.331 5.3.7.2 are met:

[0151] Upon initiation of the procedure, the UE shall:

[0152] 1> stop timer T310, if running;

[0153] 1> stop timer T312, if running;

[0154] 1> stop timer T304, if running;

[0155] 1> start timer T311;

[0156] 1> stop timer T316, if running;

[0157] 1> if UE is not configured with attemptCondReconfig; and

[0158] 1> if UE is not configured with attemptLTM-Switch:

[0159] 2> reset MAC;

[0160] 2> release spCellConfig, if configured;

[0161] 2> suspend all RBs, and BH RLC channels for IAB-MT, and Uu Relay RLC channels for L2 U2N Relay UE, except SRB0 and broadcast MRBs;

[0162] 2> release the MCG SCell(s), if configured;

[0163] 2> if MR-DC is configured:

[0164] 3> perform MR-DC release, as specified in clause 5.3.5.10;

[0165] 2> perform the LTM configuration release procedure for the MCG and the SCG as specified in clause 5.3.5.18.7;

[0166] 2> release delayBudgetReportingConfig, if configured and stop timer T342, if running;

[0167] 2> release overheatingAssistanceConfig, if configured and stop timer T345, if running;

[0168] 2> release idc-AssistanceConfig, if configured;

[0169] 2> release btNameList, if configured;

[0170] 2> release wlanNameList, if configured;

[0171] 2> release sensorNameList, if configured;

[0172] 2> release drx-PreferenceConfig for the MCG, if configured and stop timer T346a associated with the MCG, if running;

[0173] 2> release maxBW-PreferenceConfig for the MCG, if configured and stop timer T346b associated with the MCG, if running;

[0174] 2> release maxCC-PreferenceConfig for the MCG, if configured and stop timer T346c associated with the MCG, if running;

[0175] 2> release maxMIMO-LayerPreferenceConfig for the MCG, if configured and stop timer T346d associated with the MCG, if running;

[0176] 2> release minSchedulingOffsetPreferenceConfig for the MCG, if configured stop timer T346e associated with the MCG, if running;

[0177] 2> release rlm-RelaxationReportingConfig for the MCG, if configured and stop timer T346j associated with the MCG, if running;

[0178] 2> release bfd-RelaxationReportingConfig for the MCG, if configured and stop timer T346k associated with the MCG, if running;

[0179] 2> release releasePreferenceConfig, if configured stop timer T346f, if running;

[0180] 2> release onDemandSIB-Request if configured, and stop timer T350, if running;

[0181] 2> release referenceTimePreferenceReporting, if configured;

[0182] 2> release sl-AssistanceConfigNR, if configured;

[0183] 2> release obtainCommonLocation, if configured;

[0184] 2> release musim-GapAssistanceConfig, if configured and stop timer T346h, if running;

[0185] 2> release musim-GapPriorityAssistanceConfig, if configured;

[0186] 2> release musim-LeaveAssistanceConfig, if configured;

[0187] 2> release musim-CapabilityRestrictionConfig, if configured and stop timer T346n, if running;

[0188] 2> release ul-GapFR2-PreferenceConfig, if configured;

[0189] 2> release scg-DeactivationPreferenceConfig, if configured, and stop timer T346i, if running;

[0190] 2> release propDelayDiffReportConfig, if configured;

[0191] 2> release rrm-MeasRelaxationReportingConfig, if configured;

[0192] 2> release maxBW-PreferenceConfigFR2-2, if configured;

[0193] 2> release maxMIMO-LayerPreferenceConfigFR2-2, if configured;

[0194] 2> release minSchedulingOffsetPreferenceConfigExt, if configured;

[0195] 2> release multiRx-PreferenceReportingConfigFR2, if configured, and stop timer T346m, if running;

[0196] 2> release aerial-FlightPathAvailabilityConfig, if configured;

[0197] 2> release ul-TrafficInfoReportingConfig, if configured, and stop all instances of timer T346l, if running;

[0198] 1> release successHO-Config, if configured;

[0199] 1> release successPSCell-Config configured by the PCell, if configured;

[0200] 5.3.7.3Actions following cell selection while T311 is running

[0201] Upon selecting a suitable NR cell, the UE shall:

[0202] 1> ensure having valid and up to date essential system information as specified in clause 5.2.2.2;

[0203] 1> stop timer T311;

[0204] 1> if T390 is running:

[0205] 2> stop timer T390 for all access categories;

[0206] 2> perform the actions as specified in 5.3.14.4;

[0207] 1> stop the relay (re)selection procedure, if ongoing;

[0208] 1> if the cell selection is triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG or mobility from NR failure, and

[0209] 1> if attemptCondReconfig is configured; and

[0210] 1> if the selected cell is not configured with CondEventT1, or the selected cell is configured with CondEventT1 and leaving condition has not been fulfilled; and

[0211] 1> if the selected cell is one of the candidate cells for which the reconfigurationWithSync is included in the masterCellGroup in the MCG VarConditionalReconfig and the condExecutionCondPSCell is not configured for the corresponding condReconfigId in the MCG VarConditionalReconfig:

[0212] 2> if the UE supports RLF-Report for conditional handover, set the choCellId in the VarRLF-Report to the global cell identity, if available, otherwise to the physical cell identity and carrier frequency of the selected cell;

[0213] 2> apply the stored condRRCReconfig associated to the selected cell and perform actions as specified in 5.3.5.3;

[0214] NOTE 1: It is left to network implementation to how to avoid keystream reuse in case of CHO based recovery after a failed handover without key change.

[0215] 1> if the cell selection is triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG for LTM cell switch procedure triggered upon the indication by lower layers as specified in clause 5.3.5.18.6; and

[0216] 1> if attemptLTM-Switch is configured; and

[0217] 1> if the selected cell is one of the LTM candidate cells in the LTM-Candidate IE within ltm-Config associated with the MCG:

[0218] 2> perform the LTM cell switch procedure for the selected LTM candidate cell according to the actions specified in 5.3.5.18.6;

[0219] NOTE 2: In case both attemptCondReconfig and attemptLTM-Switch are configured, it is left to the UE implementation which procedure to execute.

[0220] 1>else

[0221] 2> if UE is configured with attemptCondReconfig; or

[0222] 2> if UE is configured with attemptLTM-Switch:

[0223] 3> reset MAC;

[0224] 3> release spCellConfig, if configured;

[0225] 3> release the MCG SCell(s), if configured;

[0226] 3> release delayBudgetReportingConfig, if configured and stop timer T342, if running;

[0227] 3> release overheatingAssistanceConfig, if configured and stop timer T345, if running;

[0228] 3> if MR-DC is configured:

[0229] 4> perform MR-DC release, as specified in clause 5.3.5.10;

[0230] 3> release idc-AssistanceConfig, if configured;

[0231] 3> release btNameList, if configured;

[0232] 3> release wlanNameList, if configured;

[0233] 3> release sensorNameList, if configured;

[0234] 3> release drx-PreferenceConfig for the MCG, if configured and stop timer T346a associated with the MCG, if running;

[0235] 3> release maxBW-PreferenceConfig for the MCG, if configured and stop timer T346b associated with the MCG, if running;

[0236] 3> release maxCC-PreferenceConfig for the MCG, if configured and stop timer T346c associated with the MCG, if running;

[0237] 3> release maxMIMO-LayerPreferenceConfig for the MCG, if configured and stop timer T346d associated with the MCG, if running;

[0238] 3> release minSchedulingOffsetPreferenceConfig for the MCG, if configured and stop timer T346e associated with the MCG, if running;

[0239] 3> release rlm-RelaxationReportingConfig for the MCG, if configured and stop timer T346j associated with the MCG, if running;

[0240] 3> release bfd-RelaxationReportingConfig for the MCG, if configured and stop timer T346k associated with the MCG, if running;

[0241] 3> release releasePreferenceConfig, if configured and stop timer T346f, if running;

[0242] 3> release onDemandSIB-Request if configured, and stop timer T350, if running;

[0243] 3> release referenceTimePreferenceReporting, if configured;

[0244] 3> release sl-AssistanceConfigNR, if configured;

[0245] 3> release obtainCommonLocation, if configured;

[0246] 3> release scg-DeactivationPreferenceConfig, if configured, and stop timer T346i, if running;

[0247] 3> release musim-GapAssistanceConfig, if configured and stop timer T346h, if running;

[0248] 3> release musim-GapPriorityAssistanceConfig, if configured;

[0249] 3> release musim-LeaveAssistanceConfig, if configured;

[0250] 3> release musim-CapabilityRestrictionConfig, if configured and stop timer T346n, if running;

[0251] 3> release propDelayDiffReportConfig, if configured;

[0252] 3> release ul-GapFR2-PreferenceConfig, if configured;

[0253] 3> release rrm-MeasRelaxationReportingConfig, if configured;

[0254] 3> release maxBW-PreferenceConfigFR2-2, if configured;

[0255] 3> release maxMIMO-LayerPreferenceConfigFR2-2, if configured;

[0256] 3> release minSchedulingOffsetPreferenceConfigExt, if configured;

[0257] 3> release aerial-FlightPathAvailabilityConfig, if configured;

[0258] 3> release ul-TrafficInfoReportingConfig, if configured, and stop all instances of timer T346l, if running;

[0259] 3> suspend all RBs, and BH RLC channels for the IAB-MT, except SRB0 and broadcast MRBs;

[0260] 2> remove all the entries within the MCG VarConditionalReconfig, if any;

[0261] 2> perform the LTM configuration release procedure for the MCG and the SCG as specified in clause 5.3.5.18.7;

[0262] The UE informs several capabilities for the LTM. One of the capabilities is whether UE may cause interruption on DL slots on serving cells due to PDCCH ordered RACH transmission. The capability definitions in the known prior arts related to PDCCH ordered RACH transmission is given below.

[0263]

[0264]

[0265] Referring now to the drawings, and more particularly to FIGs. 1 through 14, where similar reference characters denote corresponding features consistently throughout the figures, there are shown at least one embodiment.

[0266] FIG. 1 is an example diagram illustrating a scenario for handling a radio link failure (RLF) and configuring at least one threshold parameter in a wireless communication network 100.

[0267] As illustrated in FIG. 1, the embodiments herein disclose with handling Radio Link Failure (RLF) recovery and mobility transitions in a wireless communication network 100. The UE 1102, is configured to determine if certain parameters related to conditional reconfiguration or a mobility switch attempt are set when initiating an RRC Reestablishment procedure. Based on determination, the UE 1102 either retains or releases the successPSCell configuration associated with the Primary Secondary Cell Group Cell (PSCell).

[0268] The parameters related to the conditional reconfiguration or the mobility switch attempt may include, but not limited to a attemptCondReconfig and a attemptLTM-Switch. The parameters help the UE 1102 decide whether to retain or release the successPSCell configuration. If a Conditional Handover (CHO)-based recovery or a Lower Layers Triggered Mobility (LTM)-based recovery is unsuccessful and at least one of the parameters are configured, the UE 1102 releases the successPSCell configuration. Ensures that the UE 1102 does not persist with a PSCell configuration that is no longer viable, allowing it to switch to a better-suited cell.

[0269] In another embodiment, wherein the UE 1102 determines that it cannot apply an LTM-based candidate configuration or a conditional reconfiguration while performing cell selection when a timer is active. If the parameters related to conditional reconfiguration and mobility switch attempts are configured, the UE 1102 releases the successPSCell configuration after completing cell selection while the timer is still active.

[0270] In another embodiment, wherein for configuring at least one threshold parameter in a wireless communication network 100. A network entity 1202 is responsible for configuring the UE 1102 to report a successful PSCell change along with additional information to the network entity 1202. The additional information deals with successful PSCell change and addition information. The report contains the successPSCell-Config from the source PSCell, allowing the network to monitor mobility performance and optimize handover management. The network entity then configures the UE 1102 to execute PSCell changes using Signaling Radio Bearer 3 (SRB3) via an RRC Reconfiguration message. SRB3 is used to handle control signaling related to Secondary Cell Group (SCG) transitions, ensuring that the UE 1102 transitions smoothly between PSCells.

[0271] In another embodiment as disclosed herein, the configured threshold parameters include T310-SCG and T312-SCG, to identify the issues in the configuration for SCG mobility. Timers T310 and T312 are related to radio link failures. UE 1102 starts the timer T310 when it identifies certain issues on the radio link. UE 1102 starts T312 when it identifies certain issues on the radio link and UE 1102 has measurements to be reported for certain measurement identifiers. T310-SCG threshold indicates the threshold for the ratio in percentage between the elapsed T310 timer associated to the measurement identity of the target PSCell and the configured value of the T310 timer. T312-SCG threshold indicates the threshold for the ratio in percentage between the elapsed T312 timer associated to the measurement identity of the target PSCell and the configured value of the T312 timer. T310 threshold and T312 threshold can be used in SHR configuration. T310-SCG and T312-SCG thresholds can be used in SPR configuration. These thresholds help the UE 1102 manage connectivity and optimize failure recovery mechanisms. Handling RLF failure, is about handling successPSCell-Config during RLF, and threshold parameters are part of successPSCell-Config..

[0272] In an embodiment, the UE 1102 receives threshold parameters T310 and T312 from the target cell for SHR determination. The UE 1102 receives useAllSCGConfig from the target in SHR configuration, which assists in mobility handling decisions. The UE 1102 applies the configured T310 and T312 thresholds from the target cell, allowing to determine the success of a handover. Therefore, ensuring that the UE 1102 applies the correct parameters for mobility management, preventing unnecessary failures during network transitions.

[0273] Another embodiment as disclosed herein, the network entity 1202 may configure the UE 1102 to report a successful PSCell change along with additional information. The network entity 1202 then configures the UE 1102 to perform a PSCell change using Signaling Radio Bearer 3 (SRB3) through an RRC Reconfiguration message. The SRB3 is responsible for handling control plane signaling specific to Secondary Cell Group (SCG) transitions, ensuring smooth and efficient mobility between cells. UE 1102 may log the information pertaining to successful PSCellChange using the configuration.

[0274] Another embodiment as disclosed herein, for determining the SHR using at least one threshold parameter by the UE 1102. The UE 1102 receives source threshold parameters ThresholdPercentage T310-r18 and ThresholdPercentage T312-r18 from the target cell, to define the logging of SHR. The network entity 1202 configures these threshold parameters, which includeThresholdPercentageT310-r18 and ThresholdPercentage T312-r18. ThresholdPercentage T310 indicates the threshold for the ratio in percentage between the elapsed T310 timer associated to the measurement identity of the target PSCell and the configured value of the T310 timer. ThresholdPercentage T312 indicates the threshold for the ratio in percentage between the elapsed T312 timer associated to the measurement identity of the target PSCell and the configured value of the T312 timer. The UE 1102 applies the configured thresholds and reports the SHR.reports the SHR.

[0275] Another embodiment as disclosed herein, wherein the Secondary Primary Reconfiguration (SPR) using threshold parameters is performed by the UE 1102. The UE 1102 receives source Threshold percentage T310-SCG-r18 and ThresholdPercentage T312-SCG-r18 from the target PSCell, ensuring that the correct parameters are applied. The UE 1102 applies the thresholds for SPR determination, allowing to determine the suitable configuration of a PSCell Change.

[0276] Another embodiment as disclosed herein, the UE 1102 performs the capability reporting process for SHR. The UE 1102 receives a UE 1102 capability Enquiry request from the gNB 500, which initiates the process of reporting SHR-related capabilities. The UE 1102 provides the capability information, including its ability to apply T310 and T312 thresholds received from the target cell for SHR determination. The reported capabilities specifically relate to radio link failure recovery, mobility management, and Successful Handover Report (SHR), ensuring that the gNB 500 is aware of the UE's 1102 capabilities for managing reporting for near failure mobility transitions.

[0277] Another embodiment as disclosed herein, the handover operation in the SHR configuration is performed between the source gNB 500A and the target gNB 500B. The target gNB 500B sends a HandoverRequest message to the source gNB 500A. The message contains HandoverPreparationInformation, including T310 and T312 threshold values, ensuring that the handover is executed with the correct failure detection parameters. The source gNB 500A processes the request and provides a HandoverRequest acknowledgment, confirming that the handover operation can proceed. The interaction between the source and target gNBs ensures that the handover is seamless and that the UE 1102 receives the correct threshold parameters for mobility and failure handling.

[0278] In an embodiment herein, the network entity configures the UE 1102 with a SHR T310 threshold (thresholdPercentageT310-r17 as defined in TS 38.331) and SHR T312 threshold (thresholdPercentageT312-r17 as defined in TS 38.331) from a source cell before the ReconfigurationSync for the handover is sent to the UE 1102.

[0279] In an embodiment herein, the source cell may include the T310 / T312 thresholds in the RRCReconfiguration containing ReconfigurationSync generated by itself for a handover in which it is the target. In an embodiment herein, the source cell may include the SHR T310 / T312 thresholds in a RRCReconfiguration message that is sent before the RRCReconfiguration including ReconfigurationWithSync for the handover to the target cell is sent.

[0280] In an embodiment herein, the network node / entity 1202 configures the UE 1102 whether the T310 threshold for SHR (thresholdPercentageT310-r17) and T312 threshold for SHR (thresholdPercentageT312-r17) in the target cell (e.g. C2) configuration can be used instead of T310 thresholds for SHR and T312 threshold for SHR in the source cell (e.g. C1) configuration for determining the successful handover report for the handover from source cell C1 to target cell (e.g., C2). The UE 1102 uses a T310 threshold for SHR and a T312 threshold for SHR in the target cell configuration based on this configuration. If the target cell configuration is not available, the UE 1102 uses the T310 threshold for SHR and the T312 threshold for SHR in the source cell configuration. In an embodiment herein, this configuration is applicable for all the parameters from the source cell which are by default used for determining the successful handover report.

[0281] In an embodiment herein, the network node / network entity 1202 configures the UE 1102 to use the T310 threshold for SHR (thresholdPercentageT310-r17) and T312 threshold for SHR (thresholdPercentageT312-r17) in the target cell (e.g., C2) configuration for determining the successful handover report for the handover from the source cell C1 to the target cell C2. The UE 1102 uses the T310 threshold for SHR and the T312 threshold for SHR in the target cell configuration based on this configuration. If this configuration is not available, the UE 1102 uses the T310 threshold for SHR and the T312 threshold for SHR in the source cell configuration. In an embodiment herein, this configuration is applicable for all the parameters from the source cell which are by default used for determining the successful handover report.

[0282] In an embodiment herein, the network node / network entity 1202 indicates UE 1102 about the T310 threshold for SHR (thresholdPercentageT310-r17) and T312 threshold for SHR (thresholdPercentageT312-r17) configurations in the target cell C2 configuration or the T310 threshold for SHR and T312 threshold for SHR in the source cell C2 configuration to be used for determining the successful handover report for the handover from source cell C1 to target cell C2. The UE 1102 uses the configuration indicated by the network node.

[0283] In an alternative embodiment herein, the network node / network entity 1202 configures the UE 1102 to use the T310 SHR threshold (thresholdPercentageT310-r17) and / or T312 SHR threshold (thresholdPercentageT312- r17) and / or T304 SHR threshold (thresholdPercentageT304-r17) in the source PScell (e.g. C1) configuration (or PCell configuration) for determining the successful handover report for the handover from the source cell (e.g., C1) to the target cell (e.g., C2). The UE 1102 uses the T310 SHR threshold and / or T312 SHR threshold and / or T304 SHR threshold in the source cell (e.g. C1) configuration if configured. If it is not configured, the UE 1102 uses T310 SHR threshold and / or T312 SHR threshold and / or in the target cell (e.g. C2) configuration. The UE 1102 logs the SHR based on the T310 T310 SHR threshold and / or T312 SHR threshold. In an embodiment herein, the configuration is applicable for all the parameters from the target cell which are by default used for determining the successful handover report.

[0284] In an embodiment herein, the configuration used by the network entity 1202 to inform the UE 1102 to use the T310 threshold for SHR (thresholdPercentageT310-r17) and T312 threshold for SHR (thresholdPercentageT310-r17) configured by the target cell (as explained the above embodiments) is an Information Element (IE) such as a flag or enumerated. If the information element is included (or if the flag is true), the UE 1102 considers the T310 threshold for SHR and the T312 threshold for SHR (as configured by the target cell). In an embodiment herein, this IE may be sent when the configuration for handover is sent or when the configuration for determining the successful handover report is sent.

[0285] Consider the case where the UE 1102 moves from the source cell C1 to the target cell C2. The UE 1102 receives the T310 threshold for SHR (thresholdPercentageT310-r17) and the T312 threshold for SHR (thresholdPercentageT312-r17) from the source cell C1. Consider that the UE 1102 also receives the T310 threshold for SHR, and the T312 threshold for SHR from the target Cell C2. In the current system, the UE 1102 uses the T310 threshold for SHR and the T312 threshold for SHR from the source cell C1 to determine the SHR.

[0286] According to embodiments as disclosed herein, the communication network 100 may instruct the UE 1102 as to which T310 SHR threshold or T312 SHR threshold is to be used. The network 100 may instruct the UE 1102 to use the thresholds from the target cell, and the UE 1102 uses T310 SHR threshold and T312 SHR threshold received from the target cell C2 for determining the SHR during the handover from the source cell C1 to the target cell C2. If there is no specific instruction from the network to use the thresholds from target cell, the UE 1102 uses T310 SHR threshold and T312 SHR threshold received from source cell C1.

[0287] In an embodiment herein, according to TS 38.331,

[0288] SuccessHO-Config-r17 ::= SEQUENCE {

[0289] thresholdPercentageT304-r17 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0290] thresholdPercentageT310-r17 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0291] thresholdPercentageT312-r17 ENUMERATED {p20, p40, p60, p80, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0292] sourceDAPS-FailureReporting-r17 ENUMERATED {true} OPTIONAL, --Need R

[0293] [

[0294] uset310T312Threshold-FromTarget-r18 ENUMERATED {true} OPTIONAL, --Need R

[0295] ]

[0296] ...

[0297] }

[0298] useT310T312Threshold-FromTarget-r18 :If this field is included in target cell SuccessHO-Config, UE 1102 uses thresholdPercentageT310-r17 and thresholdPercentageT31-r17 configured by the target cell (instead of the values in source cell configuration) during the determination of SHR.

[0299] 5.3.5.9 Other configuration

[0300] 1> if the received otherConfig includes the SuccessHO-Config (and the SuccessHO-Config is setup):

[0301] 2> if useT310T312Threshold-FromTarget-r17 is included

[0302] 3> consider the thresholdPercentageT310-r17 and thresholdPercentageT310- r17 in the target cell configuration, if included, as configured by the source PSCell.

[0303] Alternatively,

[0304] 5.3.5.9 Other configuration

[0305] 1> if the received otherConfig from target PSCell includes the SuccessHO-Config (and the SuccessHO-Config is setup):

[0306] 2> if useT310T312Threshold-FromTarget-r18 is included

[0307] 3> consider the thresholdPercentageT304-r17 and thresholdPercentageT312-r17, in the target cell configuration, if included as configured by the source PSCell.

[0308] In an embodiment herein, if the useT310T312Threshold-FromTarget-r18, the UE 1102 uses thresholdPercentageT310-r17 and thresholdPercentageT312- r17 from target cell for determining SPR. The UE 1102 may not use any thresholdPercentageT310-r17 and thresholdPercentageT312-r17 from the source cell for the PSCellChange from the current source to the target.

[0309] In an embodiment herein, useT310T312Threshold-FromTarget-r18 is included only by the target cell.

[0310] In an embodiment herein, the target cell includes the T310 threshold for SHR from (determined by) the source cell and T312 threshold for SHR from (determined by) the source cell in the SuccessHO-Config.

[0311] In an embodiment herein, the target cell includes the T310 threshold for SHR from the source cell and T312 threshold for SHR from the source cell in the SuccessHO-Config, separately from the T310 threshold for SHR and T312 threshold for SHR from the target cell. The T310 threshold for the SHR from the source cell and T312 threshold for SHR from the source cell included in the target cell's SuccessHO-Config can be used for determining the SHR from the source cell to the target cell, whereas the T310 threshold for SHR from the target cell and T312 threshold for SHR from the target cell included in the target cell's SuccessHO-Config is used for determining the SHR from the target cell to another cell (i.e., when the target becomes source).

[0312] In an embodiment herein, according to TS 38.331,

[0313] SuccessHO-Config-r17 ::= SEQUENCE {

[0314] thresholdPercentageT304-r17 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0315] thresholdPercentageT310-r17 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0316] thresholdPercentageT312-r17 ENUMERATED {p20, p40, p60, p80, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0317] sourceDAPS-FailureReporting-r17 ENUMERATED {true} OPTIONAL, --Need R

[0318] [

[0319] sourceThresholdPercentageT310-r18 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0320] sourceThresholdPercentageT312-r18 ENUMERATED {p20, p40, p60, p80, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0321] ]

[0322] ...

[0323] }

[0324] sourceThresholdPercentageT310-r18: This field is included in SuccessHO-Config configured by the target cell. If this field is configured, UE 1102 uses it (instead of thresholdPercentageT310-r17 included in the source cell OtherConfig) during the determination of a successful handover report.

[0325] UE 1102 uses sourceThresholdPercentageT310-r18 from a target PSCell's OtherConfig as if it is the thresholdPercentageT310-r17 received from the sourcecell's OtherConfig.

[0326] sourceThresholdPercentageT312-r18: This field is included in SuccessHO-Config configured by the target cell. If this field is configured, UE 1102 uses it (instead of thresholdPercentageT312-r17 included in the source cell OtherConfig) during the determination of a successful handover report.

[0327] UE 1102 uses sourceThresholdPercentageT312-r18 from a target PSCell's OtherConfig as if it is the thresholdPercentageT312-r17 received from the sourcecell's OtherConfig.

[0328] 5.3.5.9Other configuration

[0329] 1> if the received otherConfig includes the SuccessHO-Config (and the SuccessHO-Config is setup):

[0330] 2> if sourceThresholdPercentageT310-r18 is included

[0331] 3> consider the sourceThresholdPercentageT310-r18, as the thresholdPercentageT310- r17 configured by the source cell.

[0332] 2> if sourceThresholdPercentageT312-r18 is included

[0333] 3> consider the sourceThresholdPercentageT312-r18, as the thresholdPercentageT312- r17 configured by the source cell.

[0334] Alternatively,

[0335] 5.3.5.9 Other configuration

[0336] 1> if the received otherConfig from target PSCell includes the SuccessHO-Config (and the SuccessHO-Config is setup):

[0337] 2> if sourceThresholdPercentageT310-r18 is included

[0338] 3> consider the sourceThresholdPercentageT310-r18, as the thresholdPercentageT310- r17 configured by the source cell.

[0339] 2> if sourceThresholdPercentageT312-r18 is included

[0340] 3> consider the sourceThresholdPercentageT312-r18, as the thresholdPercentageT312- r17 configured by the source cell.

[0341] In an embodiment herein, the source cell informs the target cell to include the T310 threshold for SHR and the T312 threshold for SHR as determined by the source cell in the OtherConfig configured by the target cell. This information may be sent from the source cell to the target cell in the HandoverPreparationInformation message.

[0342] In an embodiment herein, the source cell informs the target cell of the T310 threshold for SHR and the T312 threshold for SHR as determined by the source cell to the target cell. This information may be sent from the source cell to the target cell in HandoverPreparationInformation message. The target cell includes the T310 threshold for SHR and T312 threshold for SHR as received from the source cell in the RRCReconfiguration message including ReconfiguationWithSync which is sent to the UE 1102 for performing handover from the source cell to the target cell. In an embodiment herein, the target cell includes the T310 threshold for SHR and the T312 threshold for SHR as received from the source cell as sourceThresholdPercentageT310-r18 and sourceThresholdPercentageT312-r18 (or variables with similar functionality). In an embodiment herein, the target cell includes the T310 threshold for SHR and the T312 threshold for SHR as received from the source cell as thresholdPercentageT310- r17 and ThresholdPercentageT312-r17 and also includes useT310T312Threshold-FromTarget-r18 (or variables with similar functionality).

[0343] In an example spec from TS 38.331,

[0344] -- ASN1START

[0345] -- TAG-HANDOVER-PREPARATION-INFORMATION-START

[0346] HandoverPreparationInformation ::= SEQUENCE {

[0347] criticalExtensions CHOICE {

[0348] c1 CHOICE{

[0349] handoverPreparationInformation HandoverPreparationInformation-IEs,

[0350] spare3 NULL, spare2 NULL, spare1 NULL

[0351] },

[0352] criticalExtensionsFuture SEQUENCE {}

[0353] }

[0354] }

[0355] HandoverPreparationInformation-IEs ::= SEQUENCE {

[0356] ue-CapabilityRAT-List UE-CapabilityRAT-ContainerList,

[0357] sourceConfig AS-Config OPTIONAL, -- Cond HO

[0358] rrm-Config RRM-Config OPTIONAL,

[0359] as-Context AS-Context OPTIONAL,

[0360] nonCriticalExtension SEQUENCE {} OPTIONAL

[0361] }

[0362] AS-Context ::= SEQUENCE {

[0363]

[0364] <only relevant IEs shown>

[0365] [[

[0366] needForGapNCSG-InfoNR-r17 NeedForGapNCSG-InfoNR-r17 OPTIONAL,

[0367] needForGapNCSG-InfoEUTRA-r17 NeedForGapNCSG-InfoEUTRA-r17 OPTIONAL,

[0368] mbsInterestIndication-r17 OCTET STRING (CONTAINING MBSInterestIndication-r17) OPTIONAL

[0369] ]],

[0370] [[

[0371] thresholdPercentageT310-r18 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL,

[0372] thresholdPercentageT312-r18 ENUMERATED {p20, p40, p60, p80, spare4, spare3, spare2, spare1} OPTIONAL,

[0373] ]]

[0374] }

[0375] -- TAG-HANDOVER-PREPARATION-INFORMATION-STOP

[0376] -- ASN1STOP

[0377] thresholdPercentageT310-r18 and thresholdPercentageT312-r18 are the T310 and T312 thresholds for SHR as determined by the source cell.

[0378] In an embodiment herein, the target PSCell includes the T310-SCG threshold for SPR from the source PSCell and the T312-SCG threshold for SPR from the source PSCell in the SuccessPSCell-Config, separately from the T310-SCG threshold for SPR and the T312-SCG threshold for SPR from the target PSCell. The T310-SCG threshold for SPR from the source PSCell and T312-SCG threshold for SPR from the source PScell included in the target PSCell's SuccessPSCell-Config is used for determining the SPR from the source PSCell to the target PSCell, whereas the T310 threshold for SPR from the target PSCell and the T312 threshold for SPR from the target PSCell included in the target PSCell's SuccessPSCell-Config is used for determining the SPR for a PSCellChange from the target PSCell to another PSCell where the target PSCell becomes the source PSCell

[0379] In an embodiment herein, according to TS 38.331,

[0380] SuccessPSCell-Config-r18 ::= SEQUENCE {

[0381] thresholdPercentageT304-SCG-r18 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0382] thresholdPercentageT310-SCG-r18 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0383] thresholdPercentageT312-SCG-r18 ENUMERATED {p20, p40, p60, p80, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0384] sourceThresholdPercentageT310-SCG-r18 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0385] sourceThresholdPercentageT312-SCG-r18 ENUMERATED {p20, p40, p60, p80, spare4, spare3, spare2, spare1} OPTIONAL, --Need R

[0386] ...

[0387] }

[0388] sourceThresholdPercentageT310-SCG-r18: This field is included in SuccessPSCell-Config configured by the target PSCell. If this field is configured, the UE 1102 uses it (instead of thresholdPercentageT310-SCG-r18 included in the source PSCell OtherConfig) during the determination of successful PSCellAddition or Change information.

[0389] UE 1102 uses sourceThresholdPercentageT310-SCG-r18 from a target PSCell's OtherConfig as if it is the thresholdPercentageT310-SCG-r18 received from the source PSCell's OtherConfig.

[0390] sourceThresholdPercentageT312-SCG-r18: This field is included in SuccessPSCell-Config configured by the target PSCell. If this filed is configured, UE 1102 uses it (instead of thresholdPercentageT312-SCG-r18 included in the source PSCell OtherConfig) during the determination of successful PSCellAddition or Change information.

[0391] sourceThresholdPercentageT312-SCG-r18 from a target PSCell's OtherConfig as if it is the thresholdPercentageT312-SCG-r18 received from the source PSCell's OtherConfig.

[0392] 5.3.5.9 Other configuration

[0393] 1> if the received otherConfig includes the SuccessPSCell-Config (and the SuccessPSCell-Config is setup) :

[0394] 2> if sourceThresholdPercentageT310-SCG-r18 is included

[0395] 3> consider the sourceThresholdPercentageT310-SCG-r18, as the thresholdPercentageT310-SCG- r18 configured by the source cell.

[0396] 2> if sourceThresholdPercentageT312-SCG-r18 is included

[0397] 3> consider the sourceThresholdPercentageT312-SCG-r18, as the thresholdPercentageT312- SCG-r18 configured by the source cell.

[0398] Alternatively,

[0399] 5.3.5.9 Other configuration

[0400] 1> if the received otherConfig from target PSCell includes the SuccessPSCell-Config (and the SuccessPSCell-Config is setup):

[0401] 2> if sourceThresholdPercentageT310-SCG-r18 is included

[0402] 3> consider the sourceThresholdPercentageT310-SCG-r18, as the thresholdPercentageT310-SCG- r18 configured by the source cell.

[0403] 2> if sourceThresholdPercentageT312-SCG-r18 is included

[0404] 3> consider the sourceThresholdPercentageT312-SCG-r18, as the thresholdPercentageT312- SCG-r18 configured by the source cell.

[0405] In an embodiment herein, the UE 1102 informs the network whether it is capable of using the T310 and T312 thresholds for SHR in the target cell's configuration (i.e., SuccessHO-Config). In Nr, This may be informed in the UECapabilityInformation RRC message as a single bit of per-UE capability. The network uses this information to configure sourceThresholdPercentageT310-r18 or sourceThresholdPercentageT312-r18 or useT310T312Threshold-FromTarget-r18 in the target cell's SuccessHO-Config.

[0406] In an embodiment herein, the UE 1102 informs the network whether it is capable of using the T310 and T312 thresholds for SHR in the target cell's configuration (i.e., SuccessHO-Config); i.e., the UE 1102 informs whether it is capable of handling the fields sourceThresholdPercentageT310-r18 or sourceThresholdPercentageT312-r18 or useT310T312Threshold-FromTarget-r18 in SHR configuration as per the above embodiments in this invention. In NR, this may be informed in the UECapabilityInformation RRC message as a single bit of per-UE capability. The Network uses this information to configure sourceThresholdPercentageT310-r18 or sourceThresholdPercentageT312-r18 or useT310T312Threshold-FromTarget-r18 in the target cell's SuccessHO-Config.

[0407] In an embodiment herein, the UE 1102 informs the network whether it is capable of using the T310-SCG and T312-SCG thresholds for SPR in the target PSCell's configuration (i.e., SuccessPSCell-Config). This may be informed in the UECapabilityInformation RRC message as a single bit of per-UE capability. The Network uses this information to configure sourceThresholdPercentageT310-SCG-r18 or sourceThresholdPercentageT312-SCG-r18 or useT310T312Threshold-FromTarget-r18 in the target cell's SuccessHO-Config.

[0408] In an embodiment herein, the network node configures the UE 1102 with the T310-SCG threshold (thresholdPercentageT310-SCG-r18) and T312-SCG threshold (thresholdPercentageT312-SCG-r18) from the source PSCell before the ReconfigurationSync for the PSCellChange send to the UE 1102 when the RRCReconfiguration including ReconfigurationWithSync is send over SRB3. The source PSCell may include the T310 / T312 thresholds in the RRCReconfiguration containing ReconfigurationSync generated by itself for a PSCellChange in which it is the target. The source PSCell may include the T310 / T312 thresholds in a RRCReconfiguration message sent before the RRCReconfiguration including ReconfigurationWithSync is sent when the the RRCReconfiguration including ReconfigurationWithSync for the PSCellChange to the target PScell is sent over SRB3.

[0409] In an embodiment herein, whenever the source cell includes SuccessHO-Config, it is included as a setup. In an embodiment herein, whenever the target cell includes SuccessHO-Config, it is included as a setup.

[0410] In an embodiment herein, whenever source PSCell includes SuccessPSCell-Config, it is included as setup. In an embodiment herein, whenever target PSCell includes SuccessPSCell-Config, it is included as a setup.

[0411] In an embodiment herein, whenever PCell includes SuccessPSCell-Config, it is included as a setup.

[0412] FIG. 2 is an example flow diagram for determining a successful handover report (SHR). As illustrated in flow diagram 200, in step 202, the UE 1102 may receive threshold parameters T310 and T312 for SHR from the target cell. In step 204, the UE 1102 may receive useAllSCGConfig from target in SHR configuration. In step 206, the UE 1102 may apply threshold parameter T310 and T312 threshold for SHR from the target cell for SHR determination.

[0413] As illustrated in flow diagram 200, the process begins with the network entity 1202 configuring the UE 1102 to report a successful PSCell change along with additional information. The UE 1102 is responsible for detecting when the PSCell transition occurs and sending a corresponding report to the network, allowing the network entity 1202 to monitor mobility transitions effectively.

[0414] Once the UE 1102 reports the PSCell change, the network entity 1102 proceeds to configure the UE 1102 to perform PSCell change through Signaling Radio Bearer 3 (SRB3) in an RRC Reconfiguration message. The SRB3 is used to manage control plane signaling specifically for secondary cell group (SCG) configurations. This ensures that the UE 1102 applies new mobility configurations while maintaining connection stability.

[0415] The next phase involves setting threshold parameters to regulate network transitions. The UE 1102 is configured to handle T310-SCG and T312-SCG thresholds, which influence the UE 1102 responding to the RLF and mobility events. The T310-SCG (ThresholdPercentageT310-SCG-r18) defines the timer expiration for detecting radio link failures on the secondary cell group (SCG), while the T312-SCG (ThresholdPercentageT312-SCG-r18) determines the waiting time before the UE 1102 declares a failure or attempts reestablishment.

[0416] FIG. 3 is an example flow diagram for determining the SHR using at least one threshold parameter. As illustrated in FIG. 3 of the flow diagram 300, in step 302, the UE 1102 may be configured to receive source ThresholdPErcentage T310-r18 and source ThresholdPercentage T312-r18 from the target cell.

[0417] The network entity 1202 configures at least one threshold parameter, which may include, but not limited to T310-SCG (ThresholdPercentageT310-SCG-r18) and T312-SCG (ThresholdPercentageT312-SCG-r18). T310-SCG parameter defines the timer expiration threshold for detecting radio link failures on the Secondary Cell Group (SCG). The T312-SCG parameter defines the waiting time before a failure is declared or a reestablishment procedure is initiated.

[0418] The threshold parameters may help the UE 1102 to determine when to reattempt PSCell reconfiguration, declare link failure, or switch to an alternative cell. In step 304, the UE 1102 may apply the configured thresholds and adjusts connectivity. Once the UE 1102 receives the new configurations, applies the T310-SCG and T312-SCG thresholds to regulate its response to potential radio link failures. Therefore, if the T310-SCG timer expires, the UE 1102 initiates an RLF recovery procedure. If the T312-SCG threshold is reached, the UE 1102 declares failure and may initiate a reestablishment or handover process.

[0419] FIG. 4 is an example flow diagram for determining the SPR using at least one threshold parameters. In step 402 of the flow diagram 400, the UE 1102 may receive source ThresholdPercentage T310-SCG-r18 and source ThresholdPercentage T312-SCG-r18 from the target PSCell. In step 404, the UE 1102 may apply T310-SCG and T312-SCG threshold for SPR from the target PSCell for SPR determination.

[0420] FIG. 5 is an example diagram depicting the UE 1102 performing UE 1102 capability reporting for the SHR. As depicted in FIG. 5, in step 1, the UE 1102 receives the UE 1102 capability request from a gNB 500. In step 2, the UE 1102 may provide the capability information including the capability to apply T310 and T312 thresholds received from the target cell for SHR determination. Specifically in relation to radio link failure recovery, mobility management, and secondary handover recovery (SHR).

[0421] FIG. 6 is an example diagram depicting the interaction of the source gNB and target gNB for performing a handover operation in the SHR configuration. As depicted in FIG. 6, the source gNB 500A and the target gNB 500B interact to perform handover. In step 1, the target gNB 500B may send a HandoverRequest including HandoverPreparationInformation containing T310 and T312 threshold for SHR configuration. In step 2, the source gNB 500A on receiving the request may provide HandoverRequest acknowledgement to perform the hand over operation.

[0422] FIG. 7 is an example flow diagram illustrating a scenario of successPSCell-Config with attempt conditional reconfiguration / LTM. As illustrated in FIG. 7, the flow diagram 700 depicts the UE 1102 and a network entity 1202 handling a radio link failure (RLF) and mobility transitions. The step begins with 702, for determining the RLF. In step 704, the UE 1102 determines whether parameters related to a conditional reconfiguration and a mobility switch attempt are configured. The parameters comprise attemptCondReconfig and attemptLTM-Switch, which influence whether the UE 1102 retains or releases the successPSCell configuration. In step 706, if the parameters related to conditional reconfiguration and mobility switch attempt are configured, the UE 1102 retains the successPSCell configuration as part of the reestablishment process. In step 108, if the parameters are not configured, the UE 1102 releases the successPSCell configuration configured by the PSCell.

[0423] FIG. 8 is an example flow diagram illustrating the scenario performing cell selection while T311 is running with successPSCell-Config. As illustrated in FIG. 8, the flow diagram 800 begins with cell selection while a timer T311 is running. In step 802, the UE 1102 determines whether the parameters associated with conditional reconfiguration and mobility switch such as attemptCondReconfig or attemptLTM-Switch are configured. In step 804, the UE 1002 on determining that the parameters are configured, may release successPSCell-Config configured by the PSCell.

[0424] The flow diagram 800 accounts for situations where the UE 1102 is unable to apply LTM-based candidate configurations or conditional reconfiguration during cell selection while a timer is active. In such cases, the UE 1102 releases the PSCell configuration after completing cell selection. The threshold parameters T310 and T312 are used for optimized mobility.

[0425] FIG. 9 is an example flow diagram illustrating the scenario of performing cell selection while T311 is running with attempt conditional reconfiguration / LTM. As illustrated in flow diagram 900, in step 902, the cell selection while the timer T311 is active. In step 904, checks whether the UE 1102 has applied the stored condRRCReconfig associated to the selected cell and has not performed LTM cell switch procedure for the selected LTM candidate cell. In step 304, on determining that the UE 1102 has not performed LTM cell switch for the selected LTM candidate cell may proceed to the step 906. In step 906, if the attemptCondReconfig or attemptLTM-Switch is configured, may proceed to step 908. In step 908, the UE 1102 reset MAC, releases successPSCell-Config and perform other UE 1102 related operations.

[0426] FIG. 10 is an example sequence diagram illustrating the scenario of a UE 1102 capability reporting for PDCCH ordered RACH. As illustrated in FIG. 4, the sequence diagram illustrates the interaction between the UE 1102and a Next-Generation NodeB / Base Station (gNB) 500 for handling PDCCH order RACH (Physical Downlink Control Channel ordered Random Access Channel) configuration and scheduling within a wireless communication network.

[0427] In step 1, begins with the UE 1102, capability enquiry request from the gNB 500. The UE 1102, may set capability for interruption handling during PDCCH order RACH for the cell group. The UE 1102, configures itself to recognize and respond to PDCCH orders that trigger a random-access procedure, which is essential for establishing and maintaining a connection with the gNB 500.

[0428] In step 2, the UE 1102, has set capability, may interact with the gNB 500, responsible for handling the scheduling and allocation of grants for the cell group. The gNB 500 processes the received configuration from the UE 1102 and ensures that resources are allocated efficiently, based on the current network conditions and the UE's capabilities.

[0429] Hence, ensures that the UE 1102 and the gNB 500 remain synchronized, allowing for smooth RACH-based access procedures, for network access, mobility, and radio link recovery. The interaction facilitates dynamic resource allocation and ensures that the UE 1102 can successfully perform access procedures while minimizing latency and disruptions.

[0430] FIG. 11 shows various hardware components of the UE 1102 for handling the radio link failure (RLF) in a wireless communication network 100. In an embodiment, the UE 1102 comprises a processor 1104, a memory 1106, a communicator 1108, and a radio link failure (RLF) controller 1110. The processor 1104 is coupled with the communicator 1108, the memory 1106, and the RLF controller 1110.

[0431] The RLF controller 1110 may determine whether at least one parameter related to either conditional reconfiguration or a mobility switch attempt is configured at the time of initiating RRC Reestablishment. If the parameters are detected, the RLF controller 1110 instructs the UE 1102 to retain the successPSCell configuration, allowing the UE 1102 to continue operating with the previously assigned Primary Secondary Cell (PSCell).

[0432] If the RLF controller 1110 determines that neither conditional reconfiguration nor the mobility switch attempt is configured, directs the UE 1102 to release the successPSCell configuration. Enabling to reset and select a new cell for reestablishment, preventing the UE 1102 from relying on an outdated or non-functional PSCell configuration.

[0433] Therefore, the RLF controller 1110 operates by first evaluating whether at least one parameter related to the conditional reconfiguration or the mobility switch attempt is present when the RRC Reestablishment procedure is initiated. If the parameters are configured, the controller indicates that the UE 1102 was undergoing the planned reconfiguration or mobility switch, which retains the existing PSCell configuration.

[0434] When the RLF controller 1110 determines that conditional reconfiguration or a mobility switch attempt is configured, directs the UE 1102 to retain the successPSCell configuration. The UE 1102 continues using the previously assigned PSCell. By retaining the PSCell configuration, the UE 1102 avoids unnecessary interruptions and can quickly resume communication with the network.

[0435] If the RLF controller 1110 determines that neither the conditional reconfiguration nor the mobility switch attempt is configured, decides to release the successPSCell configuration. Hence, allowing the UE 1102 to discard the previous PSCell.

[0436] The interaction between the RLF controller 1110, the processor 1104, and the memory 1106 ensures that radio link failure recovery is handled efficiently.

[0437] The embodiment herein focuses on handling Primary Secondary Cell (PSCell) configuration during Radio Link Failure (RLF) recovery in a wireless communication network. Involves determining parameters related to conditional reconfiguration and mobility switch attempts for determining whether to retain or release the successPSCell configuration based on various network conditions.

[0438] The parameters such as attemptCondReconfig and attemptLTM-Switch, are used to manage PSCell transitions. The parameters indicate whether the conditional reconfiguration or the mobility switch attempt has been triggered.

[0439] The embodiment includes scenarios where the UE 1102 may need to release the successPSCell configuration. If Conditional Handover (CHO) based recovery or Lower Layers Triggered Mobility (LTM) based recovery is not successful, and if the conditional reconfiguration or / and the mobility switch attempt has been configured, the UE 1102 releases the successPSCell configuration. Ensuring that the UE 1102 does not continue using a PSCell that is no longer viable, allowing it to transition to a more stable network connection.

[0440] In another embodiment, when the UE 1102 determines that it is unable to apply an LTM-based candidate configuration or the conditional reconfiguration while performing cell selection. If the timer is active and the required parameters related to conditional reconfiguration and mobility switch attempts are configured, the UE 1102 releases the successPSCell configuration. This step prevents the UE 1102 from maintaining an ineffective PSCell setup and enables it to establish a new, more suitable connection in the network.

[0441] The embodiment ensures that the UE 1102 dynamically evaluates mobility and recovery conditions about PSCell configuration retention or release based on real-time network status. By incorporating CHO-based and LTM-based recovery mechanisms, optimizes mobility transitions, enhances network stability, and improves the efficiency of RRC Reestablishment procedures in wireless communication systems.

[0442] The UE 1102 referred to herein may be an electronic device / user device that is used by the user to connect, interact, and / or control the operations of the plurality of other devices using a 3GPP network. Examples of the UE 1102 may include, but are not limited to, a smartphone, a mobile phone, a video phone, a computer, a tablet personal computer (PC), a laptop, a wearable device, television, a personal digital assistant (PDA), an IoT device, or any other device that may use a 3GPP network or non-3GPP network.

[0443] The RLF controller 1110 is 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 firmware.

[0444] The processor 1104 may include one or a plurality of processors. The one or the plurality of processors may be a general-purpose processor, such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an AI-dedicated processor such as a neural processing unit (NPU). The processor 1104 may include multiple cores and is configured to execute the instructions stored in the memory 1106.

[0445] Further, the processor 1104 is configured to execute instructions stored in the memory 1106 and to perform various processes. The communicator 1108 is configured for communicating internally between internal hardware components and with external devices via one or more networks. The memory 1106 also stores instructions to be executed by the processor 1104. The memory 1106 may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory 1106 may, in some examples, be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term "non-transitory" should not be interpreted that the memory 1106 is non-movable. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in Random Access Memory (RAM) or cache).

[0446] FIG. 12 shows various hardware components of the network entity 1202 for configuring at least one threshold parameter in the wireless communication network 100. The network entity may include, but not limited to a Next-Generation NodeB (gNB), Evolved NodeB (eNB) target gNB, source gNB, Primary Cell, Secondary Cell, Master Node (MN), Secondary Node (SN), and so on. In an embodiment, the network entity 1202 comprises a processor 1204, a memory 1206, a communicator 1208, and a threshold configuring controller 1210.

[0447] The threshold configuring controller 1210 comprises the processor 1204 responsible for executing commands related to the network entity 1202 for configuring the threshold parameters.

[0448] The threshold configuring controller 1210 may report a successful PSCell change and additional information to a network with the successPSCell-Config from a source Priamry Secondary Cell (PSCELL). The reporting includes the successPSCell-Config from the source PSCell, which helps the network track handover. The threshold configuring controller 1210 configures the UE 1102 to execute PSCell changes through Signaling Radio Bearer 3 (SRB3) using an RRC Reconfiguration message. SRB3 is the dedicated signaling bearer that allows control plane communication between the UE 1102 and the network, ensuring smooth PSCell transitions.

[0449] The threshold configuring controller 1210 of the network entity 1202 configures the UE 1102 to apply threshold parameters T310-SCG and T312-SCG. The T310-SCG threshold determines the timer expiration for detecting radio link failures in the Secondary Cell Group (SCG), while the T312-SCG threshold defines the waiting time before failure is declared or a reestablishment attempt is made.

[0450] The network entity 1202, which may be, but not limited to a gNB 500(Next-Generation NodeB), a source gNB 500A, a target gNB 500B, another control unit, interacts with the UE 1102 to send configuration updates, process PSCell reports, and monitor network transitions.

[0451] The threshold configuring controller 1210 is 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 firmware.

[0452] The processor 1204 may include one or a plurality of processors. The one or the plurality of processors may be a general-purpose processor, such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an AI-dedicated processor such as a neural processing unit (NPU). The processor 1204 may include multiple cores and is configured to execute the instructions stored in the memory 1206.

[0453] Further, the processor 1204 is configured to execute instructions stored in the memory 1206 and to perform various processes. The communicator 1208 is configured for communicating internally between internal hardware components and with external devices via one or more networks. The memory 1206 also stores instructions to be executed by the processor 1204. The memory 1206 may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory 1206 may, in some examples, be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term "non-transitory" should not be interpreted that the memory 1206 is non-movable. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in Random Access Memory (RAM) or cache).

[0454] In an embodiment, the UE 1102 logs the successful PSCell change or addition report for a MN initiated PSCell mobility based on the successful PSCell change or addition report configuration. (successPSCell-Config) from the PCell, and for a SN initiated PSCell mobility based on configuration from PSCell. When the UE 1102 recovers from a RLF based on the conditional reconfiguration or LTM configuration, there is a need for the source PSCell and the UE 1102 to be synchronized with respect to the successPSCell-Config. Similarly, when the attempt to recover fails and a new PSCell is configured, the new PSCell and the UE 1102 needs to be synchronized with respect to the successPSCell-Config.

[0455] The network entity needs to be able to configure the UE 1102 with the successPSCell-Config using SRB3 to avoid unnecessary signaling between MN and SN and between MN and UE 1102.

[0456] In an embodiment, upon selecting a suitable NR cell while T311 is running, UE 1102 checks if it has applied the stored conditional reconfiguration (condRRCReconfig) associated to the selected cell, and has not performed LTM cell switch procedure for the selected LTM candidate cell (for e.g. as in section 5.3.7.3) and if so, UE 1102 further checks whether the UE 1102 has been configured to apply the stored conditional reconfiguration (condRRCReconfig) associated to the selected cell or stored LTM candidate cell associated to the selected cell and if so, UE 1102 resets MAC, releases a set of configurations and suspend all RBs, and BH RLC channels for the IAB-MT, except SRB0 and broadcast MRBs.

[0457] In an embodiment, this can be represented as below in TS 38.331.

[0458] 5.3.7.3 Actions following cell selection while T311 is running

[0459] Upon selecting a suitable NR cell, the UE shall:

[0460] 1> ensure having valid and up to date essential system information as specified in clause 5.2.2.2;

[0461] 1> stop timer T311;

[0462] 1> if T390 is running:

[0463] 2> stop timer T390 for all access categories;

[0464] 2> perform the actions as specified in 5.3.14.4;

[0465] 1> stop the relay (re)selection procedure, if ongoing;

[0466] 1> if the cell selection is triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG or mobility from NR failure, and

[0467] 1> if attemptCondReconfig is configured; and

[0468] 1> if the selected cell is not configured with CondEventT1, or the selected cell is configured with CondEventT1 and leaving condition has not been fulfilled; and

[0469] 1> if the selected cell is one of the candidate cells for which the reconfigurationWithSync is included in the masterCellGroup in the MCG VarConditionalReconfig and the condExecutionCondPSCell is not configured for the corresponding condReconfigId in the MCG VarConditionalReconfig:

[0470] 2> if the UE supports RLF-Report for conditional handover, set the choCellId in the VarRLF-Report to the global cell identity, if available, otherwise to the physical cell identity and carrier frequency of the selected cell;

[0471] 2> apply the stored condRRCReconfig associated to the selected cell and perform actions as specified in 5.3.5.3;

[0472] NOTE 1: It is left to network implementation to how to avoid keystream reuse in case of CHO based recovery after a failed handover without key change.

[0473] 1> if the cell selection is triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG for LTM cell switch procedure triggered upon the indication by lower layers as specified in clause 5.3.5.18.6; and

[0474] 1> if attemptLTM-Switch is configured; and

[0475] 1> if the selected cell is one of the LTM candidate cells in the LTM-Candidate IE within ltm-Config associated with the MCG:

[0476] 2> perform the LTM cell switch procedure for the selected LTM candidate cell according to the actions specified in 5.3.5.18.6;

[0477] NOTE 2: In case both attemptCondReconfig and attemptLTM-Switch are configured, it is left to the UE implementation which procedure to execute.

[0478] 1>if the UE has not applied the stored condRRCReconfig associated to the selected cell and has not performed LTM cell switch procedure for the selected LTM candidate cell, as above:

[0479] 2> if UE is configured with attemptCondReconfig; or

[0480] 2> if UE is configured with attemptLTM-Switch :

[0481] 3> reset MAC;

[0482] 3> release spCellConfig, if configured;

[0483] 3> release the MCG SCell(s), if configured;

[0484] 3> release delayBudgetReportingConfig, if configured and stop timer T342, if running;

[0485] 3> release overheatingAssistanceConfig , if configured and stop timer T345, if running;

[0486] 3> if MR-DC is configured:

[0487] 4> perform MR-DC release, as specified in clause 5.3.5.10;

[0488] 3> release idc-AssistanceConfig, if configured;

[0489] 3> release btNameList, if configured;

[0490] 3> release wlanNameList, if configured;

[0491] 3> release sensorNameList, if configured;

[0492] 3> release drx-PreferenceConfig for the MCG, if configured and stop timer T346a associated with the MCG, if running;

[0493] 3> release maxBW-PreferenceConfig for the MCG, if configured and stop timer T346b associated with the MCG, if running;

[0494] 3> release maxCC-PreferenceConfig for the MCG, if configured and stop timer T346c associated with the MCG, if running;

[0495] 3> release maxMIMO-LayerPreferenceConfig for the MCG, if configured and stop timer T346d associated with the MCG, if running;

[0496] 3> release minSchedulingOffsetPreferenceConfig for the MCG, if configured and stop timer T346e associated with the MCG, if running;

[0497] 3> release rlm-RelaxationReportingConfig for the MCG, if configured and stop timer T346j associated with the MCG, if running;

[0498] 3> release bfd-RelaxationReportingConfig for the MCG, if configured and stop timer T346k associated with the MCG, if running;

[0499] 3> release releasePreferenceConfig, if configured and stop timer T346f, if running;

[0500] 3> release onDemandSIB-Request if configured, and stop timer T350, if running;

[0501] 3> release referenceTimePreferenceReporting, if configured;

[0502] 3> release sl-AssistanceConfigNR, if configured;

[0503] 3> release obtainCommonLocation, if configured;

[0504] 3> release scg-DeactivationPreferenceConfig, if configured, and stop timer T346i, if running;

[0505] 3> release musim-GapAssistanceConfig, if configured and stop timer T346h, if running;

[0506] 3> release musim-GapPriorityAssistanceConfig, if configured;

[0507] 3> release musim-LeaveAssistanceConfig, if configured;

[0508] 3> release musim-CapabilityRestrictionConfig, if configured and stop timer T346n, if running;

[0509] 3> release propDelayDiffReportConfig, if configured;

[0510] 3> release ul-GapFR2-PreferenceConfig, if configured;

[0511] 3> release rrm-MeasRelaxationReportingConfig, if configured;

[0512] 3> release maxBW-PreferenceConfigFR2-2, if configured;

[0513] 3> release maxMIMO-LayerPreferenceConfigFR2-2, if configured;

[0514] 3> release minSchedulingOffsetPreferenceConfigExt, if configured;

[0515] 3> release aerial-FlightPathAvailabilityConfig, if configured;

[0516] 3> release ul-TrafficInfoReportingConfig, if configured, and stop all instances of timer T346l, if running;

[0517] 3> suspend all RBs, and BH RLC channels for the IAB-MT, except SRB0 and broadcast MRBs;

[0518] 2> remove all the entries within the MCG VarConditionalReconfig, if any;

[0519] 2> perform the LTM configuration release procedure for the MCG and the SCG as specified in clause 5.3.5.18.7;

[0520] In an embodiment,

[0521] 5.3.7RRC connection re-establishment

[0522] 5.3.7.2Initiation

[0523] The UE initiates the procedure when one of the conditions such as specified in TS 38.331 5.3.7.2 are met:

[0524] Upon initiation of the procedure, the UE shall:

[0525] 1> stop timer T310, if running;

[0526] 1> stop timer T312, if running;

[0527] 1> stop timer T304, if running;

[0528] 1> start timer T311;

[0529] 1> stop timer T316, if running;

[0530] 1> if UE is not configured with attemptCondReconfig; and

[0531] 1> if UE is not configured with attemptLTM-Switch and the cell selection is triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG for LTM cell switch procedure triggered upon the indication by lower layers:

[0532] 2> reset MAC;

[0533] 2> release spCellConfig, if configured;

[0534] 2> suspend all RBs, and BH RLC channels for IAB-MT, and Uu Relay RLC channels for L2 U2N Relay UE, except SRB0 and broadcast MRBs;

[0535] 2> release the MCG SCell(s), if configured;

[0536] 2> if MR-DC is configured:

[0537] 3> perform MR-DC release, as specified in clause 5.3.5.10;

[0538] 2> perform the LTM configuration release procedure for the MCG and the SCG as specified in clause 5.3.5.18.7;

[0539] 2>A set of releases

[0540] 1> release successHO-Config, if configured;

[0541] 1> release successPSCell-Config configured by the PCell, if configured;

[0542] 5.3.7.3 Actions following cell selection while T311 is running

[0543] Upon selecting a suitable NR cell, the UE shall:

[0544] 1> ensure having valid and up to date essential system information as specified in clause 5.2.2.2;

[0545] 1> stop timer T311;

[0546] 1> if T390 is running:

[0547] 2> stop timer T390 for all access categories;

[0548] 2> perform the actions as specified in 5.3.14.4;

[0549] 1> stop the relay (re)selection procedure, if ongoing;

[0550] 1> if the cell selection is triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG or mobility from NR failure, and

[0551] 1> if attemptCondReconfig is configured; and

[0552] 1> if the selected cell is not configured with CondEventT1, or the selected cell is configured with CondEventT1 and leaving condition has not been fulfilled; and

[0553] 1> if the selected cell is one of the candidate cells for which the reconfigurationWithSync is included in the masterCellGroup in the MCG VarConditionalReconfig and the condExecutionCondPSCell is not configured for the corresponding condReconfigId in the MCG VarConditionalReconfig:

[0554] 2> if the UE supports RLF-Report for conditional handover, set the choCellId in the VarRLF-Report to the global cell identity, if available, otherwise to the physical cell identity and carrier frequency of the selected cell;

[0555] 2> apply the stored condRRCReconfig associated to the selected cell and perform actions as specified in 5.3.5.3;

[0556] NOTE 1: It is left to network implementation to how to avoid keystream reuse in case of CHO based recovery after a failed handover without key change.

[0557] 1> if the cell selection is triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG for LTM cell switch procedure triggered upon the indication by lower layers as specified in clause 5.3.5.18.6; and

[0558] 1> if attemptLTM-Switch is configured; and

[0559] 1> if the selected cell is one of the LTM candidate cells in the LTM-Candidate IE within ltm-Config associated with the MCG:

[0560] 2> perform the LTM cell switch procedure for the selected LTM candidate cell according to the actions specified in 5.3.5.18.6;

[0561] NOTE 2: In case both attemptCondReconfig and attemptLTM-Switch are configured, it is left to the UE implementation which procedure to execute.

[0562] 1>if the UE has not applied the stored condRRCReconfig associated to the selected cell and has not performed LTM cell switch procedure for the selected LTM candidate cell, as above:

[0563] 2> if UE is configured with attemptCondReconfig; or

[0564] 2> if UE is configured with attemptLTM-Switch and the cell selection was triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG for LTM cell switch procedure triggered upon the indication by lower layers:

[0565] 3> reset MAC;

[0566] 2> A set of releases

[0567] 2> remove all the entries within the MCG VarConditionalReconfig, if any;

[0568] 2> perform the LTM configuration release procedure for the MCG and the SCG as specified in clause 5.3.5.18.7;

[0569] In an embodiment, UE 1102 informs the network its capability on whether UE 1102 may cause interruption on DL slot(s) on serving cells due to PDCCH-ordered RACH transmission for the same cell group.

[0570]

[0571]

[0572] For e.g. a UE 1102 which has informed the network that it is capable of not causing interruption on DL slot(s) on serving cells due to PDCCH-ordered RACH transmission for the same cell group, receives PDCCH ordered RACH transmission of MCG, may cause interruption on a serving cell on SCG, but not on MCG. Similarly, a UE 1102 which has informed the network that it is capable of not causing interruption on DL slot(s) on serving cells due to PDCCH-ordered RACH transmission for the same cell group, receives PDCCH ordered RACH transmission of SCG, may cause interruption on a serving cell on MCG, but not on SCG.

[0573]

[0574] The UE 1102 reports the interruption length due to RF re-tuning for PDCCH ordered RACH of which the resources are not fully contained in any of UE's configured UL BWP(s) of active serving cells of the same cell group. If the UE 1102 receives PDCCH order on MCG LTM candidate cell, UE 1102 creates an interruption of the specified length due to RF re-tuning for PDCCH ordered RACH of which the resources are not fully contained in any of UE's configured UL BWP(s) of active serving cells of MCG. MN will not schedule the UE 1102 for UL transmissions or schedule any DL transmission during this interval. SN may schedule the UE 1102 for UL transmissions or schedule any DL transmission during this interval.

[0575] Similarly, if the UE 1102 receives PDCCH order on SCG LTM candidate cell, UE 1102 creates an interruption of the specified length due to RF re-tuning for PDCCH ordered RACH of which the resources are not fully contained in any of UE's configured UL BWP(s) of active serving cells of SCG. SN will not schedule the UE 1102 for UL transmissions or schedule any DL transmission during this interval. MN may schedule the UE 1102 for UL transmissions or schedule any DL transmission during this interval.

[0576] In an embodiment, UE 1102 keeps the successPSCell-Config configured by the PSCell, if configured, if the UE 1102 is configured with attemptCondReconfig (or any variable with equivalent functionality) or attemptLTM-Switch is (or any variable with equivalent functionality) while initiating RRC Reestablishment procedure (or equivalent procedure). If both attemptCondReconfig and attemptLTM-Switch are not configured, UE 1102 releases successPSCell-Config configured by the PSCell while initiating RRC connection reestablishment.

[0577] In an embodiment, if the UE 1102 is not able to apply LTM candidate configuration or conditional reconfiguration upon cell selection while T311 is running and if at least one of attemptCondReconfig and attemptLTM-Switch are configured, UE 1102 releases successPSCell-Config configured by the PSCell following cell selection while T311 is running.

[0578] In an embodiment, if the UE 1102 supports RLF-Report for LTM, set the choCellId in the VarRLF-Report to the global cell identity, if available, otherwise to the physical cell identity and carrier frequency of the selected cell.

[0579] 5.3.7RRC connection re-establishment

[0580] 5.3.7.2Initiation

[0581] The UE initiates the procedure when one of the conditions such as specified in TS 38.331 5.3.7.2 are met:

[0582] Upon initiation of the procedure, the UE shall:

[0583] 1> stop timer T310, if running;

[0584] 1> stop timer T312, if running;

[0585] 1> stop timer T304, if running;

[0586] 1> start timer T311;

[0587] 1> stop timer T316, if running;

[0588] 1> if UE is not configured with attemptCondReconfig; and

[0589] 1> if UE is not configured with attemptLTM-Switch:

[0590] 2> reset MAC;

[0591] 2> release spCellConfig, if configured;

[0592] 2> suspend all RBs, and BH RLC channels for IAB-MT, and Uu Relay RLC channels for L2 U2N Relay UE, except SRB0 and broadcast MRBs;

[0593] 2> release the MCG SCell(s), if configured;

[0594] 2> if MR-DC is configured:

[0595] 3> perform MR-DC release, as specified in clause 5.3.5.10;

[0596] 2> perform the LTM configuration release procedure for the MCG and the SCG as specified in clause 5.3.5.18.7;

[0597] 2> release delayBudgetReportingConfig, if configured and stop timer T342, if running;

[0598] 2> release overheatingAssistanceConfig, if configured and stop timer T345, if running;

[0599] 2> release idc-AssistanceConfig, if configured;

[0600] 2> release btNameList, if configured;

[0601] 2> release wlanNameList, if configured;

[0602] 2> release sensorNameList, if configured;

[0603] 2> release drx-PreferenceConfig for the MCG, if configured and stop timer T346a associated with the MCG, if running;

[0604] 2> release maxBW-PreferenceConfig for the MCG, if configured and stop timer T346b associated with the MCG, if running;

[0605] 2> release maxCC-PreferenceConfig for the MCG, if configured and stop timer T346c associated with the MCG, if running;

[0606] 2> release maxMIMO-LayerPreferenceConfig for the MCG, if configured and stop timer T346d associated with the MCG, if running;

[0607] 2> release minSchedulingOffsetPreferenceConfig for the MCG, if configured stop timer T346e associated with the MCG, if running;

[0608] 2> release rlm-RelaxationReportingConfig for the MCG, if configured and stop timer T346j associated with the MCG, if running;

[0609] 2> release bfd-RelaxationReportingConfig for the MCG, if configured and stop timer T346k associated with the MCG, if running;

[0610] 2> release releasePreferenceConfig, if configured stop timer T346f, if running;

[0611] 2> release onDemandSIB-Request if configured, and stop timer T350, if running;

[0612] 2> release referenceTimePreferenceReporting, if configured;

[0613] 2> release sl-AssistanceConfigNR, if configured;

[0614] 2> release obtainCommonLocation, if configured;

[0615] 2> release musim-GapAssistanceConfig, if configured and stop timer T346h, if running;

[0616] 2> release musim-GapPriorityAssistanceConfig, if configured;

[0617] 2> release musim-LeaveAssistanceConfig, if configured;

[0618] 2> release musim-CapabilityRestrictionConfig, if configured and stop timer T346n, if running;

[0619] 2> release ul-GapFR2-PreferenceConfig, if configured;

[0620] 2> release scg-DeactivationPreferenceConfig, if configured, and stop timer T346i, if running;

[0621] 2> release propDelayDiffReportConfig, if configured;

[0622] 2> release rrm-MeasRelaxationReportingConfig, if configured;

[0623] 2> release maxBW-PreferenceConfigFR2-2, if configured;

[0624] 2> release maxMIMO-LayerPreferenceConfigFR2-2, if configured;

[0625] 2> release minSchedulingOffsetPreferenceConfigExt, if configured;

[0626] 2> release multiRx-PreferenceReportingConfigFR2, if configured, and stop timer T346m, if running;

[0627] 2> release aerial-FlightPathAvailabilityConfig, if configured;

[0628] 2> release ul-TrafficInfoReportingConfig, if configured, and stop all instances of timer T346l, if running;

[0629] 2> release successPSCell-Config configured by the PSCell, if configured;

[0630] 1> release successHO-Config, if configured;

[0631] 1> release successPSCell-Config configured by the PCell, if configured;

[0632] 1> if any DAPS bearer is configured:

[0633] 2> reset the source MAC and release the source MAC configuration;

[0634] 2> for each DAPS bearer:

[0635] 3> release the RLC entity or entities as specified in TS 38.322 [4], clause 5.1.3, and the associated logical channel for the source SpCell;

[0636] 3> reconfigure the PDCP entity to release DAPS as specified in TS 38.323 [5];

[0637] 2> for each SRB:

[0638] 3> release the PDCP entity for the source SpCell;

[0639] 3> release the RLC entity as specified in TS 38.322 [4], clause 5.1.3, and the associated logical channel for the source SpCell;

[0640] 2> release the physical channel configuration for the source SpCell;

[0641] 2> discard the keys used in the source SpCell (the KgNB key, the KRRCenc key, the KRRCint key, the KUPint key and the KUPenc key), if any;

[0642] 1> release sl-L2RelayUE-Config, if configured;

[0643] 1> release sl-L2RemoteUE-Config, if configured;

[0644] 1> release the SRAP entity, if configured;

[0645] 1> release ncr-FwdConfig, if configured;

[0646] 1> if the UE is NCR-MT:

[0647] 2> indicate to NCR-Fwd to cease forwarding;

[0648] 1> if SL indirect path is configured:

[0649] 2> release cell identity and relay UE ID configured in sl-IndirectPathAddChange;

[0650] 2> indicate upper layers to trigger PC5 unicast link release of the SL indirect path;

[0651] 1> if N3C indirect path is configured:

[0652] 2> release n3c-IndirectPathAddChange;

[0653] 2> consider the non-3GPP connection is not used;

[0654] 1> if the UE is acting as a N3C relay UE:

[0655] 2> release n3c-IndirectPathConfigRelay;

[0656] 2> consider the non-3GPP connection is not used;

[0657] 1> if the UE is acting as L2 U2N Remote UE and MP via L2 U2N Relay UE is not configured:

[0658] 2> if the PC5-RRC connection with the U2N Relay UE is determined to be released:

[0659] 3> indicate upper layers to trigger PC5 unicast link release;

[0660] 3> perform either cell selection in accordance with the cell selection process as specified in TS 38.304

[0020] , or relay selection as specified in clause 5.8.15.3, or both;

[0661] 2> else (i.e., maintain the PC5 RRC connection):

[0662] 3> consider the connected L2 U2N Relay UE as suitable and perform actions as specified in clause 5.3.7.3a;

[0663] NOTE 1: It is up to Remote UE implementation whether to release or keep the current PC5 unicast link.

[0664] 1> else:

[0665] 2> if the UE is capable of L2 U2N Remote UE:

[0666] 3> perform either cell selection as specified in TS 38.304

[0020] , or relay selection as specified in clause 5.8.15.3, or both;

[0667] 2> else:

[0668] 3> perform cell selection in accordance with the cell selection process as specified in TS 38.304

[0020] .

[0669] NOTE 2: For L2 U2N Remote UE, if both a suitable cell and a suitable relay are available, the UE can select either one based on its implementation.

[0670] 5.3.7.3Actions following cell selection while T311 is running

[0671] Upon selecting a suitable NR cell, the UE shall:

[0672] 1> ensure having valid and up to date essential system information as specified in clause 5.2.2.2;

[0673] 1> stop timer T311;

[0674] 1> if T390 is running:

[0675] 2> stop timer T390 for all access categories;

[0676] 2> perform the actions as specified in 5.3.14.4;

[0677] 1> stop the relay (re)selection procedure, if ongoing;

[0678] 1> if the cell selection is triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG or mobility from NR failure, and

[0679] 1> if attemptCondReconfig is configured; and

[0680] 1> if the selected cell is not configured with CondEventT1, or the selected cell is configured with CondEventT1 and leaving condition has not been fulfilled; and

[0681] 1> if the selected cell is one of the candidate cells for which the reconfigurationWithSync is included in the masterCellGroup in the MCG VarConditionalReconfig and the condExecutionCondPSCell is not configured for the corresponding condReconfigId in the MCG VarConditionalReconfig:

[0682] 2> if the UE supports RLF-Report for conditional handover, set the choCellId in the VarRLF-Report to the global cell identity, if available, otherwise to the physical cell identity and carrier frequency of the selected cell;

[0683] 2> apply the stored condRRCReconfig associated to the selected cell and perform actions as specified in 5.3.5.3;

[0684] NOTE 1: It is left to network implementation to how to avoid keystream reuse in case of CHO based recovery after a failed handover without key change.

[0685] 1> if the cell selection is triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG for LTM cell switch procedure triggered upon the indication by lower layers as specified in clause 5.3.5.18.6; and

[0686] 1> if attemptLTM-Switch is configured; and

[0687] 1> if the selected cell is one of the LTM candidate cells in the LTM-Candidate IE within ltm-Config associated with the MCG:

[0688] 2> if the UE supports RLF-Report for LTM, set the choCellId in the VarRLF-Report to the global cell identity, if available, otherwise to the physical cell identity and carrier frequency of the selected cell;

[0689] 2> perform the LTM cell switch procedure for the selected LTM candidate cell according to the actions specified in 5.3.5.18.6;

[0690] NOTE 2: In case both attemptCondReconfig and attemptLTM-Switch are configured, it is left to the UE implementation which procedure to execute.

[0691] 1>if the UE has not applied the stored condRRCReconfig associated to the selected cell and has not performed LTM cell switch procedure for the selected LTM candidate cell, as above:

[0692] 2> if UE is configured with attemptCondReconfig; or

[0693] 2> if UE is configured with attemptLTM-Switch:

[0694] 3> reset MAC;

[0695] 3> release spCellConfig, if configured;

[0696] 3> release the MCG SCell(s), if configured;

[0697] 3> release delayBudgetReportingConfig, if configured and stop timer T342, if running;

[0698] 3> release overheatingAssistanceConfig, if configured and stop timer T345, if running;

[0699] 3> if MR-DC is configured:

[0700] 4> perform MR-DC release, as specified in clause 5.3.5.10;

[0701] 3> release idc-AssistanceConfig, if configured;

[0702] 3> release btNameList, if configured;

[0703] 3> release wlanNameList, if configured;

[0704] 3> release sensorNameList, if configured;

[0705] 3> release drx-PreferenceConfig for the MCG, if configured and stop timer T346a associated with the MCG, if running;

[0706] 3> release maxBW-PreferenceConfig for the MCG, if configured and stop timer T346b associated with the MCG, if running;

[0707] 3> release maxCC-PreferenceConfig for the MCG, if configured and stop timer T346c associated with the MCG, if running;

[0708] 3> release maxMIMO-LayerPreferenceConfig for the MCG, if configured and stop timer T346d associated with the MCG, if running;

[0709] 3> release minSchedulingOffsetPreferenceConfig for the MCG, if configured and stop timer T346e associated with the MCG, if running;

[0710] 3> release rlm-RelaxationReportingConfig for the MCG, if configured and stop timer T346j associated with the MCG, if running;

[0711] 3> release bfd-RelaxationReportingConfig for the MCG, if configured and stop timer T346k associated with the MCG, if running;

[0712] 3> release releasePreferenceConfig, if configured and stop timer T346f, if running;

[0713] 3> release onDemandSIB-Request if configured, and stop timer T350, if running;

[0714] 3> release referenceTimePreferenceReporting, if configured;

[0715] 3> release sl-AssistanceConfigNR, if configured;

[0716] 3> release obtainCommonLocation, if configured;

[0717] 3> release scg-DeactivationPreferenceConfig, if configured, and stop timer T346i, if running;

[0718] 3> release musim-GapAssistanceConfig, if configured and stop timer T346h, if running;

[0719] 3> release musim-GapPriorityAssistanceConfig, if configured;

[0720] 3> release musim-LeaveAssistanceConfig, if configured;

[0721] 3> release musim-CapabilityRestrictionConfig, if configured and stop timer T346n, if running;

[0722] 3> release propDelayDiffReportConfig, if configured;

[0723] 3> release ul-GapFR2-PreferenceConfig, if configured;

[0724] 3> release rrm-MeasRelaxationReportingConfig, if configured;

[0725] 3> release maxBW-PreferenceConfigFR2-2, if configured;

[0726] 3> release maxMIMO-LayerPreferenceConfigFR2-2, if configured;

[0727] 3> release minSchedulingOffsetPreferenceConfigExt, if configured;

[0728] 3> release aerial-FlightPathAvailabilityConfig, if configured;

[0729] 3> release ul-TrafficInfoReportingConfig, if configured, and stop all instances of timer T346l, if running;

[0730] 3> suspend all RBs, and BH RLC channels for the IAB-MT, except SRB0 and broadcast MRBs;

[0731] 3> release successPSCell-Config configured by the PSCell, if configured;

[0732] 2> remove all the entries within the MCG VarConditionalReconfig, if any;

[0733] 2> perform the LTM configuration release procedure for the MCG and the SCG as specified in clause 5.3.5.18.7.

[0734] FIG. 13 is a flow chart S1300 depicting a method for handling the RLF in the wireless communication network 100. As depicted in FIG. 13, in step S1302, the UE 1102 may determine whether at least one parameter related to at least one of: the conditional re-configuration, and the mobility switch attempt is configured, while initiating the RRC Reestablishment procedure. In step S1304, the UE 1102: retaining successPSCell configuration configured by a Primary Secondary Cell Group Cell (PSCell), on determining that the at least one parameter related to the at least one of: the conditional re-configuration, and the mobility switch attempt is configured. In step S1306, the UE 1102 may perform releasing successPSCell configuration configured by the PSCell, on determining that the at least one parameter related to at least one of: the conditional re-configuration, and the mobility switch attempt is not configured.

[0735] FIG. 14 is a flow chart S1400 depicting a method for configuring at least one threshold parameter in the wireless communication network 100. As depicted in FIG. 14, in step S1402, the network entity 1202 may configure the UE 1102 to report at least one of: the successful PSCell change and the addition information to the network with a successPSCell-Config from the source Primary Secondary Cell (PSCell).

[0736] In step S1404, the network entity 1202 may configure the UE 1102 to perform PSCell change through a Signalling Radio Bearer 3 (SRB3) in the RRC Reconfiguration message.

[0737] The various actions, acts, blocks, steps, or the like in the flow charts / diagrams (200, 300, 400, 700, 800, 900, S1300-S1400) may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some of the actions, acts, blocks, steps, or the like may be omitted, added, modified, skipped, or the like without departing from the scope of the invention.

[0738] 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.

[0739] 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.

[0740] 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 practiced with modification within the scope of the embodiments as described herein.

Claims

1.A method performed by a terminal in a wireless communication system, the method comprising:receiving, from a base station, a message;identifying that the message comprises at least one of first information on a conditional reconfiguration or second information on a layer 1 (L1) / layer 2 (L2) triggered mobility (LTM); andin case that the message comprises at least one of the first information or second information, releasing third information on a successful primary secondary cell group (SCG) Cell (PSCell) change or addition except fourth information on the successful PSCell change or addition,wherein the third information is configured by a primary cell (PCell), andwherein the fourth information is configured by a PSCell.2.The method of claim 1, further comprising:in case that the message does not comprise the at least one of the first information or second information, releasing the third information and the fourth information.3.The method of claim 1, further comprising:in case that a selected cell is not one of LTM candidate cells, releasing the third information and the fourth information,wherein the identifying comprises identifying that the message comprises the at least one of the first information or the second information while initiating radio resource control (RRC) re-establishment procedure or upon a cell selection.4.The method of claim 1, further comprising:receiving, from the base station, at least one of fifth information on a threshold associated with a T310 timer or sixth information on a threshold associated with a T312 timer,wherein the at least one of the fifth information or the sixth information is not configured at the time of a PSCell change via a signaling radio bearer 3 (SRB3).5.A method performed by a base station in a wireless communication system, the method comprising:generating a message comprising at least one of first information on a conditional reconfiguration or second information on a layer 1 (L1) / layer 2 (L2) triggered mobility (LTM); andtransmitting, to a terminal, the message;wherein, in case that the message comprises at least one of the first information or second information, third information on a successful primary secondary cell group (SCG) Cell (PSCell) change or addition is released by the terminal except fourth information on the successful PSCell change or addition,wherein the third information is configured by a primary cell (PCell), andwherein the fourth information is configured by a PSCell.6.The method of claim 5,wherein, in case that the message does not comprise the at least one of the first information or second information, the third information and the fourth information are released by the terminal,wherein, in case that a selected cell is not one of LTM candidate cells, the third information and the fourth information are released by the terminal, andwherein the at least one of the first information or the second information is configured while initiating radio resource control (RRC) re-establishment procedure or upon a cell selection.7.The method of claim 5, further comprising:transmitting, to the terminal, at least one of fifth information on a threshold associated with a T310 timer or sixth information on a threshold associated with a T312 timer,wherein the at least one of the fifth information or the sixth information is not configured at the time of a PSCell change via a signaling radio bearer 3 (SRB3).8.A terminal in a wireless communication system, the terminal comprising:a transceiver; andat least one processor coupled with the transceiver and configured to:receive, from a base station, a message,identify that the message comprises at least one of first information on a conditional reconfiguration or second information on a layer 1 (L1) / layer 2 (L2) triggered mobility (LTM), andin case that the message comprises at least one of the first information or second information, release third information on a successful primary secondary cell group (SCG) Cell (PSCell) change or addition except fourth information on the successful PSCell change or addition,wherein the third information is configured by a primary cell (PCell), andwherein the fourth information is configured by a PSCell.9.The terminal of claim 8, wherein the at least one processor is further configured to:in case that the message does not comprise the at least one of the first information or second information, release the third information and the fourth information.10.The terminal of claim 8, wherein the at least one processor is further configured to:in case that a selected cell is not one of LTM candidate cells, release the third information and the fourth information,wherein the identifying comprises identifying that the message comprises the at least one of the first information or the second information while initiating radio resource control (RRC) re-establishment procedure or upon a cell selection.11.The terminal of claim 8, wherein the at least one processor is further configured to:receive, from the base station, at least one of fifth information on a threshold associated with a T310 timer or sixth information on a threshold associated with a T312 timer,wherein the at least one of the fifth information or the sixth information is not configured at the time of a PSCell change via a signaling radio bearer 3 (SRB3).12.A base station in a wireless communication system, the base station comprising:a transceiver; andat least one processor coupled with the transceiver and configured to:generate a message comprising at least one of first information on a conditional reconfiguration or second information on a layer 1 (L1) / layer 2 (L2) triggered mobility (LTM), andtransmit, to a terminal, the message,wherein, in case that the message comprises at least one of the first information or second information, third information on a successful primary secondary cell group (SCG) Cell (PSCell) change or addition is released by the terminal except fourth information on the successful PSCell change or addition,wherein the third information is configured by a primary cell (PCell), andwherein the fourth information is configured by a PSCell.13.The base station of claim 12,wherein, in case that the message does not comprise the at least one of the first information or second information, the third information and the fourth information are released by the terminal.14.The base station of claim 12,wherein, in case that a selected cell is not one of LTM candidate cells, the third information and the fourth information are released by the terminal, andwherein the at least one of the first information or the second information is configured while initiating radio resource control (RRC) re-establishment procedure or upon a cell selection.15.The base station of claim 12, wherein the at least one processor is further configured to:transmit, to the terminal, at least one of fifth information on a threshold associated with a T310 timer or sixth information on a threshold associated with a T312 timer,wherein the at least one of the fifth information or the sixth information is not configured at the time of a PSCell change via a signaling radio bearer 3 (SRB3).

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