Method and apparatus for optimizing low layer triggen mobility (LTM) in communication system

Abstract

The present disclosure relates to a 5G or 6G communication system supporting a higher data transmission rate. A method performed by a terminal in the system includes receiving a message including configuration information about a successful handover from a base station, and releasing the configuration information about the successful handover in a case where the terminal performs Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM) cell handover, where the LTM cell handover is triggered by the base station.

Description

Technical Field

[0001] This invention relates to telecommunications network systems. More specifically, this disclosure relates to optimizing low-level triggered mobility (LTM) in telecommunications network systems. Background Technology

[0002] 5G mobile communication technology defines a wide frequency band, enabling high transmission speeds and new services. This can be achieved not only in "sub-6GHz" bands such as 3.5GHz, but also in "above-6GHz" bands, including 28GHz and 39GHz, which are known as millimeter waves. Furthermore, to achieve transmission speeds 50 times faster than 5G and ultra-low latency only one-tenth that of 5G, the industry is considering deploying 6G mobile communication technology (referred to as "super 5G systems") in terahertz bands (e.g., the 95GHz to 3terahertz band).

[0003] In the early stages of 5G mobile communication technology development, standardization of the following technologies has been ongoing to support services related to enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC) and meet performance requirements: beamforming and massive multiple-input multiple-output (MIMO) for mitigating radio wave path loss and increasing radio wave transmission distance in millimeter waves; parameter set support (e.g., operating multiple subcarrier spacings) for dynamic operation to efficiently utilize millimeter wave resources and time slot formats; initial access technologies to support multi-beam transmission and broadband; definition and operation of BWP (bandwidth portion); new channel coding methods (e.g., LDPC (low-density parity-check) codes for large data transmissions and polar codes for highly reliable transmission of control information); L2 preprocessing; and network slicing for providing dedicated networks specifically for particular services.

[0004] Currently, given the services that 5G mobile communication technology will support, discussions are underway regarding improvements and performance enhancements to the initial 5G mobile communication technology. Furthermore, physical layer standardization has been implemented for the following technologies: V2X (Vehicle-to-Everything) technology, used to assist autonomous vehicles in making driving decisions and improve user convenience based on vehicle location and status information transmitted from vehicles; NR-U (New Radio Unlicensed) technology, designed to enable system operation in unlicensed frequency bands to meet various regulatory requirements; NR UE power saving technology; NTN (Non-Terrestrial Network) technology, i.e., UE-satellite direct communication used to provide coverage in areas where communication with terrestrial networks is impossible; and positioning technology.

[0005] In addition, standardization is underway for the following technologies regarding air interface architecture / protocol approach: Industrial Internet of Things (IIoT) for supporting new services through interoperability and convergence with other industries; IAB (Integrated Access and Backhaul) for providing nodes for network service area extension by comprehensively supporting wireless backhaul links and access links; mobility enhancements (including conditional handover and DAPS (Dual Active Protocol Stack) handover); and two-step random access (NR two-step RACH) for simplifying the random access process. Regarding system architecture / services, standardization is also progressing for the following technologies: 5G baseline architecture (e.g., 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 UE location-based reception services.

[0006] With the commercialization of 5G mobile communication systems, an exponential increase in connected devices will access communication networks. Therefore, enhancing the functionality and performance of 5G mobile communication systems, as well as the integrated operation of connected devices, will become essential. To this end, new research is planned in the following areas: Extended Reality (XR) for efficient support of AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality), etc.; improving 5G performance and reducing complexity by leveraging Artificial Intelligence (AI) and Machine Learning (ML); AI service support; Metaverse service support; and drone communication.

[0007] Furthermore, this development of 5G mobile communication systems will not only lay the foundation for the development of technologies such as: novel waveforms for providing coverage in the terahertz band of 6G mobile communication technology; multi-antenna transmission technologies such as full-dimensional MIMO (FD-MIMO), array antennas, and massive MIMO; metamaterial lenses and antennas for improving terahertz band signal coverage; high-dimensional spatial multiplexing technologies using OAM (orbital angular momentum); and RIS (reconfigurable smart surfaces), but will also lay the foundation for the development of technologies such as: full-duplex technologies for improving the frequency efficiency of 6G mobile communication technology and improving system networks; AI-based communication technologies for system optimization using satellites and artificial intelligence (AI) from the design stage and for built-in end-to-end AI support; and next-generation distributed computing technologies for enabling services with complexity exceeding the operational capabilities of UEs by utilizing ultra-high-performance communication and computing resources in the network.

[0008] In recent years, with global technical activities by industry and academia targeting various candidate technologies, the development momentum of fifth-generation (5G) or new radio (NR) mobile communications has become increasingly strong. Candidate enabling technologies for 5G / NR mobile communications include: massive MIMO technology from traditional cellular bands to high-frequency bands (for providing beamforming gain and supporting capacity increases), new waveforms that can flexibly adapt to various services / applications with different needs (such as new radio access technologies (RAT)), and new multiple access schemes that can support massive connectivity. The 5G NR (new radio) radio access network (also known as the next-generation radio access network (NG-RAN)) comprises multiple NR base stations called gNodeBs (gNBs). gNBs can be connected via the Xn interface and will connect to various core network elements such as Access and Mobility Management Functions (AMF) and User Plane Functions (UPF). Furthermore, gNBs can be divided into two physical entities: Centralized Units (CUs) and Distributed Units (DUs). The CU provides support for higher layers of the protocol stack, such as Session Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP), and Radio Resource Control (RRC), while the DU provides support for lower layers, such as Radio Link Control (RLC), Media Access Control (MAC), and the physical layer. Each gNB can contain multiple cells, serving a large number of User Equipments (UEs). It is particularly important to note that identifying optimal radio parameters and the process by which operators use manual techniques such as drive testing to determine these parameters is quite challenging. However, such manual parameter tuning is costly because it depends on many factors, such as the number of users, the number of neighboring cells, the maximum cell throughput, and the average cell throughput. Furthermore, many manual operations need to be repeated whenever a new neighboring gNB is deployed or a new service is introduced. To address this issue, 3GPP introduced Self-Organizing Network (SON) technology in radio technologies such as NR. SON was first introduced in the LTE system in 3GPP Release 9. SON solutions can be categorized into three types: self-configuration, self-optimization, and self-healing. SON architectures can be centralized, distributed, or hybrid solutions. Mobility Robustness Optimization (MRO) is a SON technique used to optimize various parameters related to mobility.

[0009] According to 3GPP specifications (such as TS 38.300 V17.3.0), MRO is designed to detect and correct connection failures caused by intra-system or inter-system mobility, unnecessary inter-system home visits (premature inter-system home visits from NR to E-UTRAN without radio link failure), and inter-system home visit ping-pong. MRO provides methods to distinguish these issues from NR coverage-related issues and other non-mobility-related issues.

[0010] One of the functions of MRO is to detect suboptimal successful handover events. The goal is to identify potential conditions during normal successful handover, DAPS successful handover, or conditional successful handover. To analyze successful handovers, the UE supports network configuration-based methods (e.g., via the IE defined in the 3GPP technical specification TS 38.331 for NR). successHO-Config The network receives a Successful Handover Report (SHR) and, if received, provides it to the network. Upon receiving the SHR, the network-side receiving node analyzes whether adjustments to mobility configuration are needed. The SHR supports Layer 3 (L3) mobility. successHO-Config The definition is as follows: SuccessHO-Config-r17 ::= SEQUENCE { thresholdPercentageT304-r17 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R thresholdPercentageT310-r17 ENUMERATED {p40, p60, p80, spare5, spare4, spare3, spare2, spare1} OPTIONAL, --Need R thresholdPercentageT312-r17 ENUMERATED {p20, p40, p60, p80, spare4, spare3, spare2, spare1} OPTIONAL, --Need R sourceDAPS-FailureReporting-r17 ENUMERATED {true} OPTIONAL, --Need R } Therefore, it is necessary to address the aforementioned shortcomings or other deficiencies, or at least provide an effective alternative. Summary of the Invention

[0011] Technical issues

[0012] With the development of communication systems, there is an urgent need for a method to optimize low-level triggered mobility (LTM).

[0013] The technical objectives pursued in this disclosure are not limited to those described above, and other unmentioned technical objectives can be clearly understood by those skilled in the art through the following description.

[0014] The main objective of this invention is to optimize LTM in telecommunications network systems.

[0015] Another objective of this invention is to optimize Low Layer Triggered Mobility (LTM) in NR through successful handover reporting and radio link failure (RLF) reporting.

[0016] Another objective of this invention is to process successful configuration switching during RLF.

[0017] Another objective of this invention is to ensure enhancements in RLF reporting for specific reasons related to LTM cell handover.

[0018] Another objective of this invention is to ensure enhancements in RLF reporting by utilizing LTM-related parameters.

[0019] Another object of the present invention is to provide a method for configuring and evaluating SHR thresholds for LTM.

[0020] Another object of the present invention is to provide a method for performing SHR reporting for LTM.

[0021] Another objective of this invention is to handle the SHR of L3 mobility during LTM cell handover.

[0022] Technical solution

[0023] This invention optimizes LTM in a telecommunications network system. The UE (101) receives the SHR configuration of at least one of the source cell and the target cell from signaling messages of the network device (201) for reporting a successful handover. Furthermore, the UE determines whether the SHR configuration is for LTM or for Layer 3 (L3) mobility. Further, the UE determines whether one or more SHR conditions for LTM are met based on the SHR configuration. Further, when one or more SHR conditions for LTM are met, the UE stores the LTM SHR. Furthermore, after the UE successfully hands over from the source cell to the target cell, the UE sends the SHR to the network device.

[0024] In one aspect, the above objective is achieved by providing a method for optimizing Low-Layer Triggered Mobility (LTM) in a telecommunications network system. The method includes: a User Equipment (UE) receiving a Successful Handover Report (SHR) configuration for at least one of a source cell and a target cell from signaling messages from a network device, for reporting a successful handover. Further, the method includes: the UE determining whether the SHR configuration is for LTM or for Layer 3 (L3) mobility. Further, the method includes: when the SHR configuration is for LTM, the UE determining whether one or more SHR conditions for LTM are met based on the SHR configuration of at least one of the source cell and the target cell. Further, the method also includes: when one or more SHR conditions for LTM are met, the UE storing the LTM SHR. The SHR includes at least one of an LTM measurement result, an SHR cause, a source cell ID, and a target cell ID. Furthermore, the method includes: after the UE successfully hands over from the source cell to the target cell, the UE sending the SHR to the network device.

[0025] In an embodiment, the SHR configuration of the source cell includes at least one of a first threshold percentage of a first timer and a second threshold percentage of a second timer.

[0026] In this embodiment, the signaling message configures a first timer value for a first timer and a second timer value for a second timer.

[0027] In this embodiment, the SHR configuration of the target cell includes a third threshold percentage of a third timer.

[0028] In this embodiment, a third timer value is configured for the third timer in the signaling message.

[0029] In this embodiment, the signaling message is at least one of a Radio Resource Control (RRC) reconfiguration message and an RRC recovery message.

[0030] In an embodiment, the method for storing the SHR of an LTM when one or more SHR conditions of an LTM are met includes: the UE determining whether the ratio of the elapsed time of a first timer to the value of a first timer is greater than a first threshold percentage. Further, the method includes: when the ratio of the elapsed time of the first timer to the value of the first timer is greater than the first threshold percentage, the UE stores the SHR of the LTM.

[0031] In an embodiment, the method for storing the SHR of the LTM when one or more SHR conditions of the LTM are met includes: the UE determining whether the ratio of the elapsed time of the second timer on the UE side to the value of the second timer is greater than a second threshold percentage. Further, the method further includes: when the ratio of the elapsed time of the second timer on the UE side to the value of the second timer is greater than the second threshold percentage, the UE stores the SHR of the LTM.

[0032] In an embodiment, the method for storing the SHR of the LTM when one or more SHR conditions of the LTM are met includes: the UE determining whether the ratio of the elapsed time of the UE-side third timer to the value of the third timer is greater than a third threshold percentage. Further, the method further includes: when the ratio of the elapsed time of the UE-side third timer to the value of the third timer is greater than the third threshold percentage, the UE stores the SHR of the LTM.

[0033] In an embodiment, the method includes: when the SHR configuration is not used for LTM and the cell handover is for the primary cell group (MCG), the UE releases the SHR configuration of at least one of the source cell and the target cell.

[0034] In the embodiments, the LTM measurement result is at least one of the following: reference signal received power (RSRP) measurement result, signal-to-interference-plus-noise ratio (SINR) measurement result, or reference signal received quality (RSRQ) measurement result.

[0035] In one embodiment, the method includes: the UE determining whether LTM measurement is configured for the UE, and whether at least one of a radio link failure, handover failure, or LTM failure has occurred. Further, the method includes: when the UE has LTM measurement configured and at least one of a radio link failure, handover failure, or LTM failure has occurred, the UE records and sends an RLF report to the network device, the RLF report including the LTM measurement result and the cause of at least one of the radio link failure, handover failure, or LTM failure.

[0036] In this embodiment, SHR includes at least one of the following: LTM measurement results of the source cell, target cell, and neighboring cells; SHR cause; Global Cell Identifier (CGI) of the source cell, or, if the CGI of the source cell is unavailable, the Physical Cell Identifier (PCI) and New Radio Absolute Channel Number (NR-ARFCN) of the source cell; Global Cell Identifier (CGI) of the target cell, or, if the CGI of the target cell is unavailable, the Physical Cell Identifier (PCI) and New Radio Absolute Channel Number (NR-ARFCN) of the target cell; C-RNTI (Cell Radio Network Temporary Identifier); Location information; Whether the neighboring cells are LTM candidate cells; L3 measurement results of the source cell, target cell, and neighboring cells; PLMN (Public Land Mobile Network) identifier; Independent Non-Public Network (SNPN) identifier; and random access related information.

[0037] Accordingly, embodiments of the present invention provide a method for optimizing Low-Layer Triggered Mobility (LTM) in a telecommunications network system. The method includes: a network device sending a Signaling Receiver (SHR) configuration for at least one of a source cell and a target cell in a signaling message to report a successful handover. Further, the method includes: after a UE successfully hands over from the source cell to the target cell, the network device receives the SHR. Further, the method includes: the network device sending the SHR to at least one of a Distributed Unit (DU) or an Operation, Management and Maintenance Module (OAM) to optimize network resources.

[0038] Accordingly, embodiments of the present invention provide a UE in a telecommunications network system for optimizing LTM through a Successful Handover Report (SHR). The UE includes a processor and an LTM controller communicatively coupled to the processor. The LTM controller receives an SHR configuration of at least one of a source cell and a target cell from signaling messages from a network device for reporting a successful handover. Further, the LTM controller determines whether the SHR configuration is for LTM or for Layer 3 (L3) mobility. Further, when the SHR configuration is for LTM, the LTM controller determines whether one or more SHR conditions for LTM are met based on the SHR configuration of at least one of the source cell and the target cell. Further, when one or more SHR conditions for LTM are met, the LTM controller stores the LTM SHR, wherein the SHR includes at least one of an LTM measurement result, an SHR reason, a source cell ID, and a target cell ID. Further, after the UE successfully hands over from the source cell to the target cell, the LTM controller sends the SHR to the network device.

[0039] Accordingly, embodiments of the present invention provide a network apparatus for optimizing Low-Layer Triggered Mobility (LTM) in a telecommunications network system. The network apparatus includes a processor and an LTM controller communicatively coupled to the processor. The LTM controller sends a Signaling Receiver (SHR) configuration for at least one of a source cell and a target cell in a signaling message to report a successful handover. Further, the LTM controller receives the SHR after the UE successfully hands over from the source cell to the target cell. Further, the LTM controller sends the SHR to at least one of a Distributed Unit (DU) or an Operation, Management, and Maintenance (OAM) module to optimize network resources.

[0040] These and other aspects of the embodiments of the present invention will be more readily understood and appreciated in conjunction with the following description and accompanying drawings. However, it should be understood that while the following description illustrates preferred embodiments and numerous specific details, it is for illustrative purposes only and not for limitation. Various changes and modifications can be made within the scope of the embodiments of the present invention.

[0041] Beneficial effects

[0042] This disclosure provides an effective and efficient method for optimizing low-level triggered mobility (LTM). The beneficial effects achievable with this disclosure are not limited to those described above; other unmentioned effects will be readily understood by those skilled in the art through the following description. Attached Figure Description

[0043] These features, aspects, and advantages of the embodiments of the present invention will become more apparent from the following accompanying drawings, in which the same reference numerals denote the same elements throughout. The embodiments of the present invention will be better understood from the following description with reference to the accompanying drawings, in which: Figure 1 A block diagram of a UE for optimizing LTM in a telecommunications network system according to an embodiment of the present disclosure is shown; Figure 2 A block diagram of a network apparatus for optimizing LTM in a telecommunications network system according to an embodiment of the present disclosure is shown; Figure 3 A flowchart is shown of a method for optimizing LTM in a telecommunications network system according to an embodiment of the present disclosure; Figure 4 A flowchart is shown of a method for optimizing LTM in a network device in a telecommunications network system according to an embodiment of the present disclosure.

[0044] It should be noted that, where possible, the same reference numerals have been used to denote the same elements in the accompanying drawings. Furthermore, those skilled in the art should understand that the elements in the drawings are for simplification and are not necessarily drawn to scale. For example, the dimensions of some elements in the drawings may be enlarged relative to other elements to aid in understanding the embodiments of the present invention. In addition, elements in the drawings may be represented by conventional symbols, and the drawings only show specific details relevant to understanding the embodiments of the present invention, so as not to obscure the drawings due to details known to those skilled in the art. Detailed Implementation

[0045] The embodiments of the present invention and their various features and advantageous details are described in detail below with reference to the accompanying drawings. To avoid unnecessarily obscuring the essence of the embodiments of the invention, descriptions of well-known components and processing techniques will be omitted. Furthermore, the various embodiments described herein are not necessarily mutually exclusive, and some embodiments may be combined with one or more other embodiments to form new embodiments. The term "or" as used herein, unless otherwise stated, refers to a non-exclusive or. The examples used herein are intended only to help understand how the embodiments of the present invention are implemented and to further enable those skilled in the art to practice the embodiments of the present invention. Therefore, these examples should not be construed as limiting the scope of the embodiments of the present invention.

[0046] As is customary in the art, embodiments are described and illustrated according to blocks that perform the functions described herein. These blocks, referred to herein as managers, units, modules, hardware components, etc., can be physically implemented using analog and / or digital circuitry (such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits, etc.) and optionally driven by firmware and software. For example, the circuitry constituting a block can be embodied on one or more semiconductor chips or on a substrate carrier such as a printed circuit board. The circuitry constituting a block can be implemented by dedicated hardware, or by a processor (e.g., one or more programmable microprocessors and associated circuitry), or by a combination of dedicated hardware (for performing some functions of the block) and a processor (for performing other functions of the block). Each block of an embodiment of the invention can be physically divided into two or more interacting independent blocks without departing from the scope of the proposed method. Similarly, blocks of an embodiment of the invention can also be physically combined into more complex blocks without departing from the scope of the proposed method.

[0047] The accompanying drawings are provided to aid in the easy understanding of the various technical features. It should be understood that the embodiments of the present invention are not limited to what is shown in the drawings. Therefore, the proposed methods should be interpreted as extending to any modifications, equivalents, and alternatives beyond what is specifically shown in the drawings. Although the terms first, second, etc., are used herein to describe various elements, these elements are not limited by these terms. These terms are generally used to distinguish one element from another.

[0048] Accordingly, an embodiment discloses a method for optimizing LTM in a telecommunications network system. The method includes: a user equipment (UE) receiving a signaling message from a signaling message from a network device for receiving a signaling management system (SHR) configuration of at least one of a source cell and a target cell, for reporting a successful handover. Further, the method includes: the UE determining whether the SHR configuration is for LTM or for Layer 3 (L3) mobility. Further, the method includes: when the SHR configuration is for LTM, the UE determining whether one or more SHR conditions for LTM are met based on the SHR configuration of at least one of the source cell and the target cell. Further, the method includes: when one or more SHR conditions for LTM are met, the UE storing the LTM SHR. The SHR includes at least one of an LTM measurement result, an SHR cause, a source cell ID, and a target cell ID. Further, the method includes: after the UE successfully hands over from the source cell to the target cell, the UE sending the SHR to the network device.

[0049] Accordingly, embodiments disclose a method for optimizing Low-Layer Triggered Mobility (LTM) in a telecommunications network system. The method includes a network device sending a Signaling Receiver (SHR) configuration for at least one of a source cell and a target cell in a signaling message to report a successful handover. Further, the method includes the network device receiving the SHR after the UE successfully hands over from the source cell to the target cell. Further, the method includes the network device sending the SHR to at least one of a Distributed Unit (DU) or an Operation, Management, and Maintenance Module (OAM) to optimize network resources.

[0050] Accordingly, an embodiment discloses a UE in a telecommunications network system for optimizing LTM through a Successful Handover Report (SHR). The UE includes a processor and an LTM controller communicatively coupled to the processor. The LTM controller receives an SHR configuration for at least one of a source cell and a target cell from signaling messages from the network device for reporting a successful handover. Further, the LTM controller determines whether the SHR configuration is for LTM or for Layer 3 (L3) mobility. Further, when the SHR configuration is for LTM, the LTM controller determines whether one or more LTM SHR conditions are met based on the SHR configuration of at least one of the source cell and the target cell. Further, when one or more LTM SHR conditions are met, the LTM controller stores the LTM SHR, wherein the SHR includes at least one of an LTM measurement result, an SHR reason, a source cell ID, and a target cell ID. Further, after the UE successfully hands over from the source cell to the target cell, the LTM controller sends the SHR to the network device.

[0051] Accordingly, embodiments disclose a network apparatus for optimizing Low-Layer Triggered Mobility (LTM) in a telecommunications network system. The network apparatus includes a processor and an LTM controller communicatively coupled to the processor. The LTM controller sends a Signaling Receiver (SHR) configuration for at least one of a source cell and a target cell in a signaling message to report a successful handover. Further, the LTM controller receives the SHR after the UE successfully hands over from the source cell to the target cell. Further, the LTM controller sends the SHR to at least one of a Distributed Unit (DU) or an Operation, Management, and Maintenance (OAM) module to optimize network resources.

[0052] The following describes mobility in NR based on a conventional system description.

[0053] In wireless technologies such as 5G NR, devices can move between different cells. Mobility in RRC_IDLE mode is achieved through a cell reselection procedure. As of NR Release 17, mobility in RRC_CONNECTED mode is achieved through a handover procedure. Network-controlled mobility applies to UEs in RRC_CONNECTED mode. Explicit RRC signaling triggered by the gNB is applied in NR. Handover in NR typically involves three steps: handover preparation, handover execution, and handover completion. The gNB can configure the UE to report measurement results, and based on the reported measurement results or knowledge of the network topology, the gNB sends an RRC reconfiguration message to hand over the UE from the source cell to another cell called the target cell. The UE accesses the target cell and sends an RRC reconfiguration completion message. In another approach introduced in 3GPP NR Release 16, the gNB can configure conditions for the UE to trigger a handover; once the conditions are met, the UE can move to the target cell and send an RRC reconfiguration completion message. In all these methods, the UE performs handover by sending Layer 3 (RRC) messages, which leads to significant signaling overhead and latency issues. During handover, the UE can be configured to apply the full configuration during L3 handover, and if configured, the UE applies the full configuration. Handover and conditional handover (CHO) are referred to as Layer 3 mobility. In dual-connectivity scenarios, the UE can perform PSCell changes or conditional PSCell changes. In dual-connectivity scenarios, PSCell changes or conditional PSCell changes are also referred to as Layer 3 mobility; that is, handover, conditional handover, PSCell change, and conditional PSCell change all refer to L3 mobility. Furthermore, in dual-connectivity scenarios, PSCell changes or conditional PSCell changes are referred to as SCG Layer 3 mobility, and handover and CHO are referred to as MCG Layer 3 mobility.

[0054] In the proposed solution, 3GPP Release 18 is considering using low-layer (L1 / L2) triggered mobility (also known as LTM) to address this issue. According to the 3GPP definition, the goal of LTM is to reduce latency, overhead, and downtime by enabling serving cell changes through L1 / L2 signaling. Network devices (such as the gNB in ​​NR) can configure the UE to have multiple candidate cells for rapid application of candidate cell configurations. The network can further send MAC CE or L1 signaling (using a cell handover command) to dynamically switch the UE from the source cell to one of the configured candidate cells. Furthermore, LTM can be triggered based on L1 measurements rather than L3 measurements. The UE can receive LTM measurement configuration from the gNB; this LTM measurement configuration is part of the L1 measurement configuration and provides the UE with configurations for measurement and reporting, as well as report content or information included in the report.

[0055] Furthermore, in the proposed solution, when 3GPP performs LTM, it avoids resetting lower layers such as MAC whenever possible to prevent data loss and reduce additional latency in data recovery. The gNB can provide LTM candidate configurations (i.e., configure LTM candidate cells for candidate target cells via an RRC reconfiguration message). The gNB can also release or modify candidate configurations. Even after the UE moves to a candidate cell via LTM, the UE can still store the LTM configurations of other candidate cells.

[0056] Furthermore, to avoid sending large messages over the air interface, the gNB can provide LTM candidate configurations as incremental configurations instead of the full configuration. The gNB can instruct the UE to use the source cell configuration as a reference for the incremental configuration, or explicitly provide a reference configuration.

[0057] The gNB also provides the UE with configurations for performing LTM measurements on different candidate frequencies and candidate cells and for reporting based on the performed LTM measurements. The gNB provides a reference configuration, L1 measurement configuration, and candidate cell configuration in the RRC ASN.1 sequence used for LTM configuration.

[0058] This invention provides a method for optimizing LTM in a telecommunications network. The method enhances RLF reporting for specific reasons such as LTM handover. Furthermore, the method enhances RLF reporting using LTM measurement results. In addition, in the proposed method, the network device ensures that the UE is configured with an SHR threshold for LTM. The proposed method supports the UE in performing SHR reporting for LTM and managing the content of the SHR. Furthermore, the proposed method also supports simultaneous processing of SHR reports for L3 mobility and LTM.

[0059] Figure 1 A block diagram of a UE for optimizing LTM in a telecommunications network system is shown according to an embodiment of the present disclosure.

[0060] The user equipment (UE) (101) includes a processor (103), a memory (107), an I / O interface (105), and an LTM controller (109). The UE (101) may be an end user equipment that connects to a network device to obtain services. For example, the UE (101) may include, but is not limited to, mobile phones, smartphones, tablets, laptops, Internet of Things (IoT) devices, etc. In addition, the processor (103) of the UE (101) communicates with the memory (107), the I / O interface (105), and the LTM controller (109). The processor (103) is configured to execute instructions stored in the memory (107) and perform various processes. The processor (103) may include one or more processors, which may be general-purpose processors (such as central processing unit (CPU), application processor (AP), etc.), dedicated graphics processors (such as graphics processing unit (GPU), vision processing unit (VPU)) and / or dedicated artificial intelligence (AI) processors (such as neural processing unit (NPU)).

[0061] Furthermore, the memory (107) of the UE (101) includes storage units addressable by the processor (103). The memory (107) is not limited to volatile memory and / or non-volatile memory. Furthermore, the memory (107) may include one or more computer-readable storage media. The memory (107) may include non-volatile storage elements. For example, non-volatile storage elements may include magnetic hard disks, optical disks, floppy disks, flash memory, or electrically programmable memory (EPROM) or electrically erasable programmable memory (EEPROM), etc. The memory (107) may store media streams such as audio streams, video streams, haptic feedback, etc. Furthermore, the memory (107) of the UE (101) may store several types of information received from at least one network device. For example, the memory may store SHR configurations such as source cell and target cell. The SHR configuration is provided via signaling messages from the network device for reporting successful handover.

[0062] The I / O interface (105) transmits information between the memory (107) and external peripheral devices. These peripheral devices are input / output devices associated with the UE (101). The I / O interface (105) receives various information from the network device. This information received from the network device may include, but is not limited to, SHR configuration for reporting a successful handover.

[0063] The LTM controller (109) communicates with the I / O interface (105) and memory (107) to optimize LTM in a telecommunications network system. The LTM controller (109) is innovative hardware formed through the physical implementation of analog and digital circuits, including logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive and active electronic components, and optical components. The LTM controller (109) of the UE (101) receives the SHR configuration of at least one of the source cell and the target cell from signaling messages from the network device for reporting a successful handover. Further, the LTM controller (109) determines whether the SHR configuration is for LTM or for Layer 3 (L3) mobility. Further, when the SHR configuration is for LTM, the LTM controller (109) determines whether one or more SHR conditions for LTM are met based on the SHR configuration of at least one of the source cell and the target cell. Further, when one or more SHR conditions for LTM are met, the LTM controller (109) stores the LTM SHR. The SHR includes at least one of the following: LTM measurement result, SHR reason, source cell ID, and target cell ID. Furthermore, after the UE successfully hands over from the source cell to the target cell, the LTM controller (109) sends the SHR to the network device.

[0064] The following is an exemplary specification for LTM configuration and operation (Example 1):

[0065] LTM cell handover is monitored by a timer. The timer Tcellswitch is started when the UE (101) receives a cell handover command and stopped after the handover is complete. In one alternative, Tcellswitch is defined as a new timer. In another alternative, an existing NR RRC timer T304 can be used to monitor LTM cell handover, and all embodiments of Tcellswitch in this disclosure are applicable to T304 when Tcellswitch is used for LTM (e.g., monitoring LTM cell handover). Tcellswitch can be described according to the following characteristics: 1. After the UE receives the LTM cell handover MAC CE, it initiates Tcellswitch; 2. After the UE successfully completes the LTM cell handover, stop Tcellswitch; 3. If the MCG's Tcellswitch expires, the UE can declare LTM failure and initiate RRC reconstruction; 4. Tcellswitch is an RRC layer timer.

[0066] LTM measurement: A gNB (hereinafter referred to as gNB interchangeably as a network device) can configure different measurement configurations for L3 mobility (e.g., using MeasConfig IE in R17 of NR) and LTM for a UE (101). A UE (101) configured with both an L3 mobility measurement configuration (for L3 mobility configuration / performance / reporting of measurements, e.g., configured via MeasConfig IE in R17 of NR, hereinafter referred to as L3 measurement) and an LTM measurement configuration (for LTM configuration / performance / reporting of measurements, hereinafter referred to as LTM measurement) performs both L3 measurement and LTM measurement. LTM measurement is a type of L1 measurement.

[0067] L1 measurement reports for LTM can be submitted in the following ways: periodic reports on PUCCH, semi-persistent reports on PUCCH / PUSCH, and aperiodic reports on PUSCH. Additionally, L1 measurement results can be reported using MAC CE. Reports can be scheduled by the gNB or initiated by the UE; the gNB can also determine whether to execute LTM based on uplink measurements.

[0068] In the method proposed in this invention, a successful configuration switching feature (such as in NR) is configured. successHO-Config UE (101) releases the successful handover configuration when performing LTM cell handover. In one embodiment, the UE releases the successful handover configuration after receiving the cell handover command from the network. In another embodiment, the UE's RRC layer performs the release after receiving information from a lower layer (such as MAC) that the lower layer has received the cell handover command from the network. In yet another embodiment, the successful handover configuration is released when it is used to record and report successful L3 mobility. In yet another embodiment, the successful handover configuration is not released when it is used to record and report successful LTM. In another optional embodiment, the successful handover configuration is released when it is used to record and report both successful L3 mobility and LTM.

[0069] In one embodiment, after receiving a cell handover command triggered for MCG, the UE (101) releases the successful handover configuration for L3 mobility. In another embodiment, after receiving a cell handover command triggered for SCG, the UE (101) retains the successful handover configuration for L3 mobility.

[0070] In the embodiment, after the UE (101) receives a cell handover command from the network (which is triggered for the MCG), it releases the successful handover configuration configured for L3 mobility by the source cell.

[0071] In the embodiment, after the UE (101) receives a cell handover command from the network (which is triggered for the MCG), it releases the successful handover configuration configured for L3 mobility by the source cell and the T304 threshold configured by the target cell.

[0072] In the embodiment, after receiving the cell handover command from the MCG, the UE (101) releases the successful handover configuration configured for L3 mobility by the source cell and the T304 threshold configured by the target cell.

[0073] In the embodiment, the UE (101) that includes the neighboring cell measurement results in the SHR also includes whether the neighboring cell is an LTM candidate cell.

[0074] The following are exemplary sequences from a partial embodiment of the capture method in TS 38.331:

[0075] In this embodiment, a UE (101) configured with a successful handover configuration (such as successHO-Config in NR) releases the successful handover configuration when the LTM cell handover is successful.

[0076] In this embodiment, a UE (101) configured with a successful handover configuration (such as successHO-Config in NR) releases the successful handover configuration when the LTM cell handover fails.

[0077] In the embodiment, a UE (101) configured with a successful handover configuration for L3 mobility (such as successHO-Config in NR) releases the successful handover configuration when the LTM cell handover is successful.

[0078] In the embodiment, a UE (101) configured with a successful handover configuration for L3 mobility (such as successHO-Config in NR) releases the successful handover configuration when the LTM cell handover fails.

[0079] In another optional embodiment, a UE (101) configured with a successful handover configuration for L3 mobility (such as successHO-Config in NR) retains the successful handover configuration whether the LTM cell handover is successful or not.

[0080] In this embodiment, a UE (101) configured with an LTM candidate cell stores the L3 mobility successful handover report if an available LTM candidate cell measurement result exists.

[0081] In this embodiment, a UE (101) configured with LTM candidate cells stores available LTM measurement results in the L3 mobility successful handover report if these candidate cells do not have available L3 measurement results. In this embodiment, a UE configured with LTM candidate cells stores available LTM measurement results in the L3 mobility successful handover report if these cells (cells configured for the corresponding frequency) do not have L3 measurement targets.

[0082] In this embodiment, the UE (101) includes the latest LTM measurement results in the SHR of L3 mobility. In this embodiment, the UE sends the average value of the LTM measurement results over a specific time period to the network in the SHR of L3 mobility. In this embodiment, the network configures a filter for the UE to report applicable LTM measurement results in the SHR. The UE filters the LTM measurement results based on the configured filter. In this embodiment, the LTM measurement results can be any of the periodic, non-periodic, semi-periodic, or event-triggered measurements configured by the UE for LTM according to the gNB.

[0083] In this embodiment, the LTM measurement results included in the SHR are RSRP (Reference Signal Received Power) measurement results. In this embodiment, the LTM measurement results included in the L3 mobility SHR are Signal-to-Interference-Noise Ratio (SINR) measurement results. In this embodiment, the LTM measurement results included in the L3 mobility SHR are Reference Signal Received Quality (RSRQ) measurement results.

[0084] For a UE (101) configured with both LTM and L3 measurements in the same cell, the SHR for L3 mobility only includes the L3 measurement results. In another optional embodiment, for a UE configured with both LTM and L3 measurements in the same cell, the SHR for L3 mobility includes both LTM and L3 measurement results. In yet another optional embodiment, for a UE configured with both LTM and L3 measurements in the same cell, the SHR for L3 mobility includes the LTM measurement results.

[0085] LTM successful switchover report:

[0086] In this embodiment, the UE (101) receives a configuration (referred to herein as the "LTM Success Report Configuration") from a network device (such as a gNB) for reporting a successful LTM handover report. In this embodiment, the LTM Success Report Configuration is implemented using RRC IEsuccessHO-Config-r17 in the NR. In this embodiment, the configuration is received via a new NR IE. In this embodiment, for the NR, the configuration is received via RRC IE OtherConfig.

[0087] In this embodiment, the LTM success reporting configuration includes threshold percentages for timers T310 (timer T310 is interchangeably referred to as the first timer) and T312 (timer T312 is interchangeably referred to as the second timer). In this embodiment, the LTM success reporting configuration is provided via RRC messages such as RRC reconfiguration or RRC recovery. In this embodiment, the threshold percentage of timer T310 of the aforementioned LTM (the first threshold percentage is interchangeably referred to as the threshold percentage of timer T310) is configured via NR RRC IEthresholdPercentageT310. In this embodiment, the threshold percentage of timer T310 of the aforementioned LTM is configured via a new NR RRC IE.

[0088] In an embodiment, if the ratio of the elapsed time of timer T310 to the configured timer T310 value is greater than the timer T310 threshold percentage of LTM included in the LTM success report configuration, then the UE (101) stores a successful LTM handover report. In an embodiment, the NR UE (101) sets t310-cause in shr-Cause to true in this case.

[0089] In this embodiment, if the ratio of the elapsed time of timer T312 on the UE side to the configured applicable timer T312 value is greater than the timer T312 threshold percentage of LTM included in the LTM success report configuration (the second threshold percentage is interchangeably referred to as the threshold percentage of timer T312), then the UE (101) stores the successful LTM handover report. In this embodiment, the NR UE (101) sets t312-cause in shr-Cause to true in this case.

[0090] In this embodiment, the threshold percentages for timers T310 and T312 in the LTM success report configuration include the following values: thresholdPercentageT310-r17 ENUMERATED {p40, p60, p80, spare5,spare4, spare3, spare2, spare1} OPTIONAL, -- Need R thresholdPercentageT312-r17 ENUMERATED {p20, p40, p60, p80, spare4,spare3, spare2, spare1} OPTIONAL, -- Need R (p20 represents 20%, p40 represents 40%, p60 represents 60%, p80 represents 80%, and so on) In this embodiment, the threshold percentages for timers T310 (the first threshold percentage is interchanged with the threshold percentage of timer T310) and T312 (the second threshold percentage is interchanged with the threshold percentage of timer T312) in the LTM success report configuration are configured by the source cell. In this embodiment, the threshold percentages for timers T310 and T312 in the LTM success report configuration are included in the RRC message generated by the source cell.

[0091] In this embodiment, the threshold can be an absolute value, such as the duration of timer T310 or timer T312, rather than a percentage.

[0092] In this embodiment, the LTM success report configuration includes a threshold for the timer Tcellswitch (referred to as the third timer). In this embodiment, the LTM success report configuration includes a threshold percentage for the timer Tcellswitch (referred to as thresholdPercentageTcellswitch in this invention) (referred to as the third timer's threshold percentage). In this embodiment, the MCG's LTM success report configuration includes the threshold percentage thresholdPercentageTcellswitch for the timer Tcellswitch. In this embodiment, thresholdPercentageTcellswitch is set by the target gNB and included in the target cell's RRC configuration message. In this embodiment, thresholdPercentageTcellswitch is configured in the LTM candidate configuration (such as LTM-Candidate-r18 in the background art). In this embodiment, thresholdPercentageTcellswitch includes one or more of the following values: 20%, 40%, 60%, and 80%. In this embodiment, thresholdPercentageTcellswitch includes the following values: 40%, 60%, and 80%.

[0093] In this embodiment, if the ratio of the elapsed time of timer Tcellswitch to the configured timer Tcellswitch value is greater than the thresholdPercentageTcellswitch included in the LTM success report configuration, then the UE (101) stores the LTM successful handover report. In this embodiment, the successful handover reason (shr-cause) stored by the UE (101) is caused by Tcellswitch. In this embodiment, the UE sets Tcellswitch-cause in shr-cause to true in this case.

[0094] In this embodiment, the threshold matching criterion in the LTM success report configuration is based on "greater than or equal to" rather than "greater than".

[0095] In this embodiment, a UE (101) configured with LTM candidate cells or LTM measurements stores available LTM measurement results while storing a successful handover report.

[0096] In this embodiment, the UE (101) includes the latest LTM measurement result in the SHR of LTM. In this embodiment, the latest measurement result is the last measurement performed. In this embodiment, the latest measurement result is the last measurement reported. In this embodiment, the UE sends the average value of LTM measurement results over a specific time period to the network in the SHR of LTM. In this embodiment, the LTM measurement result can be any one of the periodic, non-periodic, semi-periodic, or event-triggered measurements configured by the UE for LTM according to the gNB.

[0097] In this embodiment, the LTM measurement result included in the SHR is the RSRP (Reference Signal Received Power) measurement result. In this embodiment, the LTM measurement result included in the SHR of the LTM is the SINR (Signal-to-Interference-plus-Noise Ratio) measurement result. In this embodiment, the LTM measurement result included in the SHR of the LTM is the RSRQ (Reference Signal Received Quality) measurement result.

[0098] For UEs (101) configured with both LTM and L3 measurements in the same cell, the SHR for LTM only includes L3 measurement results. In another optional embodiment, for UEs configured with both LTM and L3 measurements in the same cell, the SHR for LTM includes both LTM and L3 measurement results. In yet another optional embodiment, for UEs configured with both LTM and L3 measurements in the same cell, the SHR for LTM includes LTM measurement results.

[0099] In this embodiment, the above embodiments can be captured by the example embodiments in the following 3GPP specification TS 38.331. In the following sections, the successful handover reports for LTM and L3 handovers, as well as the configuration of successful handover reports for LTM and L3 handovers, use the same variable names.

[0100] In this embodiment, after the UE (101) receives the cell handover command from the network, it retains the successful handover configuration set for LTM. If another mobility event occurs from the same source cell, the configured timer T310 / T312 thresholds can be reused. If another mobility event occurs towards the same target cell, the configured timer Tcellswitch thresholds can be reused.

[0101] In one embodiment, the gNB can configure the thresholdPercentageTcellswitch in the LTM reference configuration. In another embodiment, the gNB can configure the thresholdPercentageTcellswitch in the LTM candidate cell configuration. In yet another embodiment, the gNB can configure the thresholdPercentageTcellswitch in any RRC reconfiguration message.

[0102] In this embodiment, the UE (101) configured with LTM successful handover reporting records and reports the information shown in Table 2 below:

[0103] Table 2

[0104] In the embodiment, after receiving the cell handover command from the network device, the UE (101) retains the successful handover configuration configured as LTM and releases the successful handover configuration configured as LTM when the network device (such as gNB) explicitly releases it, or during RRC reconstruction, or during RRC release (regardless of switching to RRC_IDLE mode or RRC_INACTIVE mode).

[0105] During timer T390 processing, when a cell handover is performed (e.g., when the UE RRC receives a cell handover command indication from a lower layer, or when a condition for performing LTM is met), the UE (101) stops the timer if it is running a timer T390 for all access classes (as defined or described in TS 38.331). In a particular embodiment, this operation applies only to cell handover commands for MCGs.

[0106] During timer T304 processing, when a cell handover is performed (e.g., when the UE RRC receives a cell handover command indication sent by a lower layer, or when a certain condition for performing LTM is met), the UE (101) stops timer T304 (as defined in TS 38.331).

[0107] In this embodiment, when LTM measurements are configured, the UE (101) updates the RLF report.

[0108] In this embodiment, a UE (101) configured with LTM measurements or an LTM candidate cell that experiences a radio link failure, handover failure, or LTM malfunction includes the latest LTM measurement result in its radio link failure report (e.g., an RLF report or handover failure report in the NR R17 specification). In this embodiment, the latest measurement result is the last measurement performed. In this embodiment, the latest measurement result is the last reported measurement. In this embodiment, the UE (101) sends the average value of the LTM measurement results over a specific time period to the network in the RLF report. In this embodiment, the LTM measurement result can be any one of the periodic, non-periodic, semi-periodic, or event-triggered measurements configured by the UE for LTM according to the gNB.

[0109] In this embodiment, the LTM measurement results included in the RLF report are RSRP (Reference Signal Received Power) measurement results. In this embodiment, the LTM measurement results included in the RLF report are SINR (Signal-to-Interference-plus-Noise Ratio) measurement results. In this embodiment, the LTM measurement results included in the RLF report are RSRQ (Reference Signal Received Quality) measurement results.

[0110] For UEs (101) configured with both LTM and L3 measurements in the same cell, the RLF report in the above case only includes L3 measurement results. In another optional embodiment, for UEs configured with both LTM and L3 measurements in the same cell, the RLF report in the above case includes both LTM and L3 measurement results. In yet another optional embodiment, for UEs configured with both LTM and L3 measurements in the same cell, the RLF report in the above case includes LTM measurement results.

[0111] In an embodiment, when LTM execution fails (e.g., timer Tcellswitch expires), the UE (101) includes an RLF reason (e.g., rlf-Cause-r16 in NR TS 38.331), which is used to inform the network that the failure was caused by an LTM failure (e.g., timer Tcellswitch expires or LTM execution fails). In an embodiment, when LTM execution fails (e.g., timer Tcellswitch expires), the UE (101) informs the network device in the RLF report that the last handover type was LTM (e.g., setting lastHO-Type-r17 to an enumerated value indicating that the last handover type was LTM).

[0112] In one embodiment, the UE (101) reports the SHR of LTM in an RRC message such as a UE Information Response. In another embodiment, the gNB CU receives the RRC message containing the SHR of LTM and uses this message to optimize the LTM configuration. In yet another embodiment, the gNB CU sends the received SHR of LTM to the gNB DU via an IFAP message (such as an Access and Mobility Indication).

[0113] Figure 2 A block diagram of a network apparatus for optimizing LTM in a telecommunications network system according to an embodiment of the present disclosure is shown.

[0114] The network device (201) includes a processor (203), a memory (207), an I / O interface (205), and an LTM controller (209). The network device (201) communicates with the UE (101) to perform self-optimization during handover. For example, the network device (201) may include, but is not limited to, a base station access point, a central server, or similar equipment. Furthermore, the processor (203) of the network device (201) communicates with the memory (207), the I / O interface (205), and the LTM controller (209). The processor (203) is configured to execute instructions stored in the memory (207) and perform various processes. The processor (203) may include one or more processors, which may be general-purpose processors (such as a central processing unit (CPU), an application processor (AP), etc.), dedicated graphics processors (such as a graphics processing unit (GPU), a vision processing unit (VPU)), and / or dedicated artificial intelligence (AI) processors (such as a neural processing unit (NPU)).

[0115] Furthermore, the memory (207) of the network device (201) includes storage units addressable by the processor (203). The memory (207) is not limited to volatile memory and / or non-volatile memory. Further, the memory (207) may include one or more computer-readable storage media, and may also include non-volatile storage elements. For example, non-volatile storage elements may include magnetic hard disks, optical disks, floppy disks, flash memory, or electrically programmable memory (EPROM) or electrically erasable programmable memory (EEPROM), etc. The memory (207) may store media streams such as audio streams, video streams, haptic feedback, etc. In addition, the memory (207) of the network device (201) may store several pieces of information received from the UE (101). For example, the memory (207) may store an SHR received from the UE (101), which includes at least one of LTM measurement results, SHR cause, source cell ID, and target cell ID.

[0116] The I / O interface (205) transmits information between the memory (207) and external peripheral devices, which are input / output devices associated with the network device (201). The I / O interface (205) receives information from the UE (101). This information received from the UE (101) may include, but is not limited to, an SHR containing at least one of the following: LTM measurement result, SHR cause, source cell ID, and target cell ID.

[0117] The LTM controller (209) communicates with the I / O interface (205) and memory (207) to optimize LTM in a telecommunications network system. The LTM controller (209) is innovative hardware formed through the physical implementation of analog and digital circuits, including logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive and active electronic components, and optical components. The LTM controller (209) of the network device (201) sends an SHR configuration of at least one of the source cell and the target cell in a signaling message to report a successful handover. Furthermore, the LTM controller (209) receives the SHR after the UE (101) successfully hands over from the source cell to the target cell. Additionally, the LTM controller (209) sends the SHR to at least one of the DU or OAM to optimize network resources.

[0118] Figure 3 A flowchart is shown of a method for optimizing LTM for a UE in a telecommunications network system according to an embodiment of the present disclosure.

[0119] In block 301, the UE (101) receives an SHR configuration for at least one of the source cell and the target cell from a signaling message of the network device (201) for reporting a successful handover. The SHR configuration includes, but is not limited to, a first threshold percentage from a first timer of the source cell and a second threshold percentage from a second timer of the network device (201). The SHR configuration also includes a third threshold percentage from a third timer of the target cell of the network device (201).

[0120] In block 303, the UE (101) determines whether the SHR configuration is for LTM or for Layer 3 (L3) mobility.

[0121] In block 305, when the SHR configuration is not for LTM and the cell handover is for the primary cell group, the UE (101) releases the SHR configuration of the source cell and the target cell.

[0122] In block 307, the UE (101) determines whether one or more SHR conditions for the LTM included in the SHR configuration are met. Specifically, the UE (101) determines whether the ratio of the elapsed time of the first timer to the value of the first timer is greater than a first threshold percentage. Additionally, the UE (101) also determines whether the ratio of the elapsed time of the second timer on the UE side to the value of the second timer is greater than a second threshold percentage. Furthermore, the UE (101) determines whether the ratio of the elapsed time of the third timer on the UE side to the value of the third timer is greater than a third threshold percentage.

[0123] In block 309, the UE (101) stores the SHR of the LTM when any one of the SHR conditions is met. Specifically, the UE (101) stores the SHR of the LTM when the ratio of the elapsed time of the first timer to the value of the first timer is greater than a first threshold percentage. Furthermore, the UE (101) stores the SHR of the LTM when the ratio of the elapsed time of the second timer on the UE side to the value of the second timer is greater than a second threshold percentage. Additionally, the UE (101) stores the SHR of the LTM when the ratio of the elapsed time of the third timer on the UE side to the value of the third timer is greater than a third threshold percentage.

[0124] In block 311, after the UE (101) successfully switches from the source cell to the target cell, the UE (101) sends the SHR to the network device (201).

[0125] Figure 4 A flowchart is shown of a method for optimizing LTM in a network device in a telecommunications network system according to an embodiment of the present disclosure.

[0126] In block 401, the network device (201) sends the SHR configuration to the UE (101). The network device contains multiple network cells, among which the cell currently accessed by the UE (101) is called the source cell. Further, during the handover process, the UE (101) moves toward the target cell. Therefore, the network device sends the SHR configurations of the source cell and the target cell to the UE (101). The SHR configuration is sent to the UE (101) for use in reporting after a successful handover from the source cell to the target cell.

[0127] In block 403, the network device (201) receives the SHR after the UE (101) successfully switches from the source cell to the target cell.

[0128] In block 405, the network device (201) sends the SHR to the DU or OAM to optimize network resources and parameters, such as the T304 timer value, random access resources, the measurement threshold that will trigger LTM, the measurement threshold that will trigger LTM early synchronization, whether to configure the UE based on TA measurement, etc.

[0129] The various actions, operations, blocks, and steps in the method can be executed in the indicated order, in a different order, or simultaneously. Furthermore, in some embodiments, certain actions, operations, blocks, and steps can be omitted, added, modified, or skipped without departing from the scope of the proposed method.

[0130] The above description of specific embodiments will fully reveal the general nature of the embodiments of the present invention, enabling those skilled in the art to easily modify and / or adapt these specific embodiments for various applications by applying present knowledge, without departing from the general concept. Therefore, such adaptations and modifications should and are intended to be understood within the meaning and scope of equivalents of the disclosed embodiments. It should be understood that the wording or terminology used herein is for descriptive purposes and not for limiting purposes. Therefore, although embodiments of the present invention have been described according to preferred embodiments, those skilled in the art will recognize that modifications can be made to the embodiments within the scope described in the present invention.

[0131] Reference number list

Claims

1. A method performed by a terminal in a wireless communication system, the method comprising: Receive a message from the base station that includes configuration information about a successful handover; as well as When the terminal performs a Layer 1 / Layer 2 L1 / L2 triggered mobility LTM cell handover, the configuration information regarding the successful handover is released. The LTM cell handover is triggered by the base station.

2. The method according to claim 1, further comprising: When the terminal performs the LTM cell handover, information about the percentage ratio threshold related to the timer is released.

3. The method according to claim 1, further comprising: In the event of a successful or failed handover of the LTM cell, the configuration information regarding a successful handover is released.

4. The method according to claim 1, in, The configuration information regarding successful handover is for LTM.

5. A method performed by a base station in a wireless communication system, the method comprising: Send a message to the terminal including configuration information about a successful handover. In the case where the terminal performs a mobility LTM cell handover triggered by Layer 1 / Layer 2 (L1 / L2), the configuration information regarding the successful handover is released. The LTM cell handover is triggered by the base station.

6. The method according to claim 5, in, When the terminal performs the LTM cell handover, information regarding the percentage ratio threshold related to the timer is released.

7. The method according to claim 5, in, In the event of a successful or failed handover in the LTM cell, the configuration information regarding a successful handover is released. The configuration information regarding successful switching is for LTM.

8. A terminal in a wireless communication system, the terminal comprising: transceiver; as well as At least one processor, coupled to the transceiver, the at least one processor being configured to: Receive a message from the base station including configuration information about a successful handover, and When the terminal performs a Layer 1 / Layer 2 L1 / L2 triggered mobility LTM cell handover, the configuration information regarding the successful handover is released. The LTM cell handover is triggered by the base station.

9. The terminal according to claim 8, wherein, The at least one processor is further configured to: When the terminal performs the LTM cell handover, information about the percentage ratio threshold related to the timer is released.

10. The terminal according to claim 8, wherein, The at least one processor is configured as follows: If the LTM cell handover is successful or fails, the successful handover configuration information is released.

11. The terminal according to claim 8, in, The configuration information regarding successful handover is for LTM.

12. A base station in a wireless communication system, the base station comprising: transceiver; as well as At least one processor, coupled to the transceiver, the at least one processor being configured to: Send a message to the terminal including configuration information about a successful handover. In the case where the terminal performs a mobility LTM cell handover triggered by Layer 1 / Layer 2 (L1 / L2), the configuration information regarding the successful handover is released. The LTM cell handover is triggered by the base station.

13. The base station according to claim 12, in, When the terminal performs the LTM cell handover, information regarding the percentage ratio threshold related to the timer is released.

14. The base station according to claim 12, in, In the event of a successful or failed handover in the LTM cell, the configuration information regarding a successful handover is released.

15. The base station according to claim 12, in, The configuration information regarding successful handover is for LTM.

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