Node, user equipment in a wireless communication system and methods performed thereby

Abstract

The present disclosure provides a node, a user equipment and a method performed by the node and the user equipment in a wireless communication system. A method performed by a fifth node in a wireless communication system, comprising: receiving first information from a fourth node, wherein the first information comprises at least one of: information related to a manner of acquiring a timing advance (TA) used by a user equipment (UE) to access a target cell, a first TA for the UE to access the target cell, a first transmission configuration indication (TCI) state for the UE to access the target cell, first beam information for the UE to access the target cell, information related to the UE being simultaneously configured with a conditional handover and a layer 1 / layer 2 triggered mobility (LTM) handover, information related to a triggering condition of a handover of the UE; receiving second information from an eighth node; and sending third information to the fourth node, wherein the third information comprises at least one of: the first information, the second information.

Description

Technical Field

[0001] This disclosure relates to the field of wireless communication technology, and more specifically, to nodes, user equipment, and methods for performing such operations in wireless communication systems. Background Technology

[0002] To meet the increased demand for wireless data communication services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or near-5G communication systems. Therefore, 5G or near-5G communication systems are also referred to as "super 4G networks" or "post-LTE systems".

[0003] Wireless communication is one of the most successful innovations in modern history. Recently, the number of subscribers to wireless communication services surpassed 5 billion and continues to grow rapidly. The demand for wireless data services is growing rapidly due to the increasing prevalence of smartphones and other mobile data devices (such as tablets, laptops, netbooks, e-book readers, and machine-type devices) among consumers and businesses. To meet the rapid growth of mobile data services and support new applications and deployments, improving the efficiency and coverage of wireless interfaces is crucial. Summary of the Invention

[0004] Embodiments of this disclosure provide a method executed by a fifth node in a wireless communication system, comprising: receiving first information from a fourth node, wherein the first information includes at least one of the following: information related to the acquisition method of the timing advance TA used by a user equipment (UE) to access a target cell, a first TA for the UE to access the target cell, a first transmission configuration indication (TCI) state for the UE to access the target cell, first beam information for the UE to access the target cell, information related to the UE being simultaneously configured with conditional handover and Layer 1 / Layer 2 triggered mobility LTM handover, and information related to the handover triggering status of the UE; receiving second information from an eighth node, wherein the second information includes at least one of the following: a second TA used when the UE successfully accesses the target cell, a third TA used when the UE fails to access the target cell, a second TCI state used when the UE successfully accesses the target cell, a third TCI state used when the UE fails to access the target cell, a second beam information used when the UE successfully accesses the target cell, and a third beam information used when the UE fails to access the target cell; and sending third information to the fourth node, wherein the third information includes at least one of the following: the first information and the second information.

[0005] According to embodiments of this disclosure, the third information is used for self-optimization of the fourth node, wherein the self-optimization includes mobility robustness optimization.

[0006] According to an embodiment of this disclosure, the third information is sent from the fourth node to the third node, wherein the third information is used by the third node to perform self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0007] According to embodiments of this disclosure, the method for obtaining the TA used by the UE to access the target cell includes at least one of the following: the TA is a TA calculated by the UE; the TA is a TA received by the UE from a third node; the TA is a TA obtained by the UE through random access.

[0008] According to embodiments of this disclosure, the information related to the triggering of the handover of the UE includes at least one of the following: the handover is based on Layer 1 measurement results; the handover is based on Layer 3 measurement results; the handover is triggered by a source node centralized unit (CU); the handover is triggered by a source node distributed unit (DU); the handover is triggered by a source node DU based on Layer 3 measurement results, wherein, in the case where the handover is triggered by a source node CU, the third information is used by the fourth node for self-optimization, wherein, in the case where the handover is triggered by a source node DU, the third information is sent from the fourth node to the third node, and wherein the third information is used by the third node for self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0009] According to embodiments of this disclosure, the third information further includes the handover failure reason and / or potential handover failure reason of the UE, wherein the handover failure reason and / or potential handover failure reason of the UE is determined based on the first information and / or the second information, wherein the handover failure reason and / or potential handover failure reason of the UE includes at least one of the following: beam error used by the UE to access the target cell, TCI state error used by the UE to access the target cell, TA failure used by the UE to access the target cell, TA failure received by the UE, and TA failure calculated by the UE.

[0010] According to embodiments of this disclosure, determining the handover failure cause and / or potential handover failure cause of the UE includes at least one of the following: if the difference between the third TA and the second TA is greater than or equal to a first threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the first TA and the second TA is greater than or equal to a second threshold, the potential handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the identifier of the third TCI state and the identifier of the second TCI state is greater than or equal to a third threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell. The TCI state used by the UE to access the target cell is incorrect; if the difference between the identifier of the first TCI state and the identifier of the second TCI state is greater than or equal to a fourth threshold, the potential handover failure reason of the UE is determined to be the TCI state used by the UE to access the target cell being incorrect; if the difference between the third beam information and the second beam information is greater than or equal to a fifth threshold, the handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell; if the difference between the first beam information and the second beam information is greater than or equal to a sixth threshold, the potential handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell.

[0011] According to embodiments of this disclosure, the third information further includes at least one of the following: the difference between the third TA and the second TA, the difference between the first TA and the second TA, the difference between the identifier of the third TCI state and the identifier of the second TCI state, the difference between the identifier of the first TCI state and the identifier of the second TCI state, the difference between the third beam information and the second beam information, and the difference between the first beam information and the second beam information.

[0012] Embodiments of this disclosure provide a method executed by a fourth node in a wireless communication system, comprising: sending first information to a fifth node, wherein the first information includes at least one of the following: information related to the acquisition method of the timing advance TA used by a user equipment (UE) to access a target cell, a first TA for the UE to access the target cell, a first transmission configuration indication (TCI) state for the UE to access the target cell, first beam information for the UE to access the target cell, information related to the UE being simultaneously configured with conditional handover and Layer 1 / Layer 2 triggered mobility LTM handover, and information related to the handover triggering status of the UE; and receiving third information from the fifth node, wherein the third information includes at least one of the following: the first information and second information, wherein the second information is sent from an eighth node to the fifth node, wherein the second information includes at least one of the following: a second TA used when the UE successfully accesses the target cell, a third TA used when the UE fails to access the target cell, a second TCI state used when the UE successfully accesses the target cell, a third TCI state used when the UE fails to access the target cell, a second beam information used when the UE successfully accesses the target cell, and a third beam information used when the UE fails to access the target cell.

[0013] According to embodiments of this disclosure, the third information is used for self-optimization of the fourth node, wherein the self-optimization includes mobility robustness optimization.

[0014] According to an embodiment of this disclosure, the method further includes: sending the third information to a third node, wherein the third information is used by the third node to perform self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0015] According to embodiments of this disclosure, the method for obtaining the TA used by the UE to access the target cell includes at least one of the following: the TA is a TA calculated by the UE; the TA is a TA received by the UE from a third node; the TA is a TA obtained by the UE through random access.

[0016] According to embodiments of this disclosure, the information related to the triggering of the handover of the UE includes at least one of the following: the handover is based on Layer 1 measurement results; the handover is based on Layer 3 measurement results; the handover is triggered by a source node centralized unit (CU); the handover is triggered by a source node distributed unit (DU); the handover is triggered by a source node DU based on Layer 3 measurement results, wherein, in the case where the handover is triggered by a source node CU, the third information is used by the fourth node for self-optimization, wherein, in the case where the handover is triggered by a source node DU, the third information is sent from the fourth node to the third node, and wherein the third information is used by the third node for self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0017] According to embodiments of this disclosure, the third information further includes the handover failure reason and / or potential handover failure reason of the UE, wherein the handover failure reason and / or potential handover failure reason of the UE is determined based on the first information and / or the second information, wherein the handover failure reason and / or potential handover failure reason of the UE includes at least one of the following: beam error used by the UE to access the target cell, TCI state error used by the UE to access the target cell, TA failure used by the UE to access the target cell, TA failure received by the UE, and TA failure calculated by the UE.

[0018] According to embodiments of this disclosure, determining the handover failure cause and / or potential handover failure cause of the UE includes at least one of the following: if the difference between the third TA and the second TA is greater than or equal to a first threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the first TA and the second TA is greater than or equal to a second threshold, the potential handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the identifier of the third TCI state and the identifier of the second TCI state is greater than or equal to a third threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell. The TCI state used by the UE to access the target cell is incorrect; if the difference between the identifier of the first TCI state and the identifier of the second TCI state is greater than or equal to a fourth threshold, the potential handover failure reason of the UE is determined to be the TCI state used by the UE to access the target cell being incorrect; if the difference between the third beam information and the second beam information is greater than or equal to a fifth threshold, the handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell; if the difference between the first beam information and the second beam information is greater than or equal to a sixth threshold, the potential handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell.

[0019] According to embodiments of this disclosure, the third information further includes at least one of the following: the difference between the third TA and the second TA, the difference between the first TA and the second TA, the difference between the identifier of the third TCI state and the identifier of the second TCI state, the difference between the identifier of the first TCI state and the identifier of the second TCI state, the difference between the third beam information and the second beam information, and the difference between the first beam information and the second beam information.

[0020] Embodiments of this disclosure provide a method executed by a user equipment (UE) in a wireless communication system, comprising: receiving a request for a radio link failure report from a fifth node; and sending the radio link failure report to the fifth node, wherein first information is sent from a fourth node to the fifth node, wherein the first information includes at least one of the following: information related to the timing advance acquisition method used by the UE to access the target cell, a first TA for the UE to access the target cell, a first transmission configuration indication (TCI) state for the UE to access the target cell, first beam information for the UE to access the target cell, information related to the UE simultaneously configuring conditional handover and Layer 1 / Layer 2 triggered mobility LTM handover, and information related to the UE's handover... The information relates to the triggering situation; wherein, the second information is sent from the eighth node to the fifth node, and the second information includes at least one of the following: the second TA used when the UE successfully accesses the target cell, the third TA used when the UE fails to access the target cell, the second TCI state used when the UE successfully accesses the target cell, the third TCI state used when the UE fails to access the target cell, the second beam information used when the UE successfully accesses the target cell, and the third beam information used when the UE fails to access the target cell; and wherein, the third information is sent from the fifth node to the fourth node, and the third information includes at least one of the following: the first information and the second information.

[0021] According to embodiments of this disclosure, the third information is used for self-optimization of the fourth node, wherein the self-optimization includes mobility robustness optimization.

[0022] According to an embodiment of this disclosure, the third information is sent from the fourth node to the third node, wherein the third information is used by the third node to perform self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0023] According to embodiments of this disclosure, the method for obtaining the TA used by the UE to access the target cell includes at least one of the following: the TA is a TA calculated by the UE; the TA is a TA received by the UE from a third node; the TA is a TA obtained by the UE through random access.

[0024] According to embodiments of this disclosure, the information related to the triggering of the handover of the UE includes at least one of the following: the handover is based on Layer 1 measurement results; the handover is based on Layer 3 measurement results; the handover is triggered by a source node centralized unit (CU); the handover is triggered by a source node distributed unit (DU); the handover is triggered by a source node DU based on Layer 3 measurement results, wherein, in the case where the handover is triggered by a source node CU, the third information is used by the fourth node for self-optimization, wherein, in the case where the handover is triggered by a source node DU, the third information is sent from the fourth node to the third node, and wherein the third information is used by the third node for self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0025] According to embodiments of this disclosure, the third information further includes the handover failure reason and / or potential handover failure reason of the UE, wherein the handover failure reason and / or potential handover failure reason of the UE is determined based on the first information and / or the second information, wherein the handover failure reason and / or potential handover failure reason of the UE includes at least one of the following: beam error used by the UE to access the target cell, TCI state error used by the UE to access the target cell, TA failure used by the UE to access the target cell, TA failure received by the UE, and TA failure calculated by the UE.

[0026] According to embodiments of this disclosure, determining the handover failure cause and / or potential handover failure cause of the UE includes at least one of the following: if the difference between the third TA and the second TA is greater than or equal to a first threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the first TA and the second TA is greater than or equal to a second threshold, the potential handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the identifier of the third TCI state and the identifier of the second TCI state is greater than or equal to a third threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell. The TCI state used by the UE to access the target cell is incorrect; if the difference between the identifier of the first TCI state and the identifier of the second TCI state is greater than or equal to a fourth threshold, the potential handover failure reason of the UE is determined to be the TCI state used by the UE to access the target cell being incorrect; if the difference between the third beam information and the second beam information is greater than or equal to a fifth threshold, the handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell; if the difference between the first beam information and the second beam information is greater than or equal to a sixth threshold, the potential handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell.

[0027] According to embodiments of this disclosure, the third information further includes at least one of the following: the difference between the third TA and the second TA, the difference between the first TA and the second TA, the difference between the identifier of the third TCI state and the identifier of the second TCI state, the difference between the identifier of the first TCI state and the identifier of the second TCI state, the difference between the third beam information and the second beam information, and the difference between the first beam information and the second beam information.

[0028] Embodiments of this disclosure provide a node device in a wireless communication system, including: a transceiver configured to transmit and receive signals; and a processor coupled to the transceiver and configured to perform a method performed by any node in the wireless communication system according to embodiments of this disclosure.

[0029] Embodiments of this disclosure provide a user equipment (UE) in a wireless communication system, including: a transceiver configured to transmit and receive signals; and a processor coupled to the transceiver and configured to perform a method executed by the UE in the wireless communication system according to embodiments of this disclosure.

[0030] Embodiments of this disclosure provide a computer-readable medium having computer-readable instructions stored thereon, which, when executed by a processor, are used to implement a method performed by any node and / or user equipment in a wireless communication system according to embodiments of this disclosure.

[0031] The method provided in this disclosure, executed by a node and / or user equipment (UE) in a wireless communication system, enables the node to perform handover analysis and configuration self-optimization based on information such as parameters used by the UE during the handover process, abnormal conditions, and / or analysis results, thereby improving network performance. Attached Figure Description

[0032] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, wherein:

[0033] Figure 1 This is an exemplary system architecture for System Architecture Evolution (SAE);

[0034] Figure 2 These are exemplary system architectures based on various embodiments of this disclosure;

[0035] Figures 3A-3G Schematic diagrams of one aspect of a method for supporting mobility self-optimization according to embodiments of the present disclosure are shown respectively;

[0036] Figure 4A A flowchart is shown of a method performed by a fifth node in a wireless communication system according to an embodiment of the present disclosure;

[0037] Figure 4B A flowchart is shown of a method performed by a fourth node in a wireless communication system according to an embodiment of the present disclosure;

[0038] Figure 4C A flowchart illustrating a method performed by a user equipment (UE) in a wireless communication system according to an embodiment of the present disclosure is shown;

[0039] Figure 5 A schematic diagram of a node according to an embodiment of this disclosure is shown; and

[0040] Figure 6 A schematic diagram of a user equipment (UE) according to an embodiment of the present disclosure is shown. Detailed Implementation

[0041] The following description, with reference to the accompanying drawings, is provided to aid in a thorough understanding of the various embodiments of this disclosure as defined by the claims and their equivalents. This description includes various specific details to aid understanding but should be considered exemplary only. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope and spirit of this disclosure. Furthermore, for clarity and brevity, descriptions of well-known functions and structures may be omitted.

[0042] The terms and wording used in the following description and claims are not limited to their dictionary meanings, but are merely used by the inventors to enable a clear and consistent understanding of this disclosure. Therefore, it will be apparent to those skilled in the art that the following description of various embodiments of this disclosure is for illustrative purposes only and not for limiting the purpose of this disclosure as defined in the appended claims and their equivalents.

[0043] It should be understood that the singular forms of “one,” “an,” and “the” include plural references unless the context clearly indicates otherwise. Thus, for example, the reference to “component surface” includes one or more such surfaces.

[0044] The terms “comprising” or “may include” refer to the presence of a corresponding disclosed function, operation, or component that may be used in the various embodiments of this disclosure, rather than limiting the presence of one or more additional functions, operations, or features. Furthermore, the terms “comprising” or “having” may be interpreted as indicating certain characteristics, numbers, steps, operations, constituent elements, components, or combinations thereof, but should not be construed as excluding the possibility of the presence of one or more other characteristics, numbers, steps, operations, constituent elements, components, or combinations thereof.

[0045] The term "or" as used in the various embodiments of this disclosure includes any of the listed terms and all combinations thereof. For example, "A or B" may include A, may include B, or may include both A and B.

[0046] Unless otherwise defined, all terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of those skilled in the art as described herein. Common terms as defined in dictionaries are to be interpreted as having a meaning consistent with the context in the relevant technical field and should not be interpreted ideally or overly formally unless expressly defined in this disclosure.

[0047] The accompanying drawings and various embodiments used to illustrate the principles of this disclosure in this patent document are for illustrative purposes only and should not be construed as limiting the scope of this disclosure in any way. Those skilled in the art will understand that the principles of this disclosure can be implemented in any suitably arranged system or apparatus.

[0048] Figure 1 This is an exemplary system architecture 100 of System Architecture Evolution (SAE). User Equipment (UE) 101 is a terminal device used to receive data. Evolved Universal Terrestrial Radio Access Network (E-UTRAN) 102 is a radio access network, including macro base stations (eNodeB / NodeB) that provide the UE with an interface to access the radio network. Mobility Management Entity (MME) 103 is responsible for managing the UE's mobility context, session context, and security information. Serving Gateway (SGW) 104 primarily provides user plane functions; MME 103 and SGW 104 may reside in the same physical entity. Packet Data Network Gateway (PGW) 105 is responsible for functions such as charging and lawful interception, and may also reside in the same physical entity as SGW 104. Policy and Charging Rules Function Entity (PCRF) 106 provides Quality of Service (QoS) policies and charging criteria. Universal Packet Radio Service Support Node (SGSN) 108 is a network node device in the Universal Mobile Telecommunications System (UMTS) that provides routing for data transmission. The Home Subscriber Server (HSS) 109 is the UE's home subsystem, responsible for protecting user information including the UE's current location, the address of the serving node, user security information, and the UE's packet data context.

[0049] Figure 2 This is an exemplary system architecture 200 according to various embodiments of the present disclosure. Other embodiments of the system architecture 200 can be used without departing from the scope of the present disclosure.

[0050] User Equipment (UE) 201 is the terminal equipment used to receive data. Next-Generation Radio Access Network (NG-RAN) 202 is the radio access network, which includes base stations (gNBs or eNBs connected to the 5G core network 5GC; eNBs connected to the 5GC are also called ng-gNBs) that provide the UE with access to the radio network interface. Access Control and Mobility Management Function Entity (AMF) 203 is responsible for managing the UE's mobility context and security information. User Plane Function Entity (UPF) 204 primarily provides user plane functions. Session Management Function Entity (SMF) 205 is responsible for session management. Data Network (DN) 206 includes services such as operator services, internet access, and third-party services.

[0051] The nodes described in this disclosure may include: gNB, gNB Central Unit (gNB CU), gNB Distributed Unit (gNB DU), gNB Central Unit Control Plane (gNB CU-CP), gNB Central Unit User Plane (gNB CU-UP), en-gNB, eNB, ng-eNB, UE, Access and Mobility Management Function (AMF), Session Management Function (SMF), Mobility Management Entity (MME), Location Management Function (LMF), and other network nodes or network logical units, as well as the cells and / or beams they manage.

[0052] The signal strength and / or signal quality and / or measurement report and / or measurement result and / or measurement report result and / or signal measurement result mentioned in this disclosure may be Received Signal Strength Indicator (RSSI), Reference Signal Receiving Power (RSRP), Reference Signal Receiving Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), etc.

[0053] In this disclosure, failure type, problem type, and report type can refer to each other.

[0054] In this disclosure, self-optimization network (SON) related reports may include one or more of the following: Connection Establishment Failure (CEF) reports, Random Access reports, Successful Handover reports, RadioLink Failure (RLF) reports, measurement reports, or other reports related to wireless connectivity.

[0055] In this disclosure, wireless link failure can include both wireless link failure and handover failure. Wireless link failure can include failure that occurs after a successful handover. Wireless link failure can also be extended to include any type of failure such as beam failure.

[0056] The information and / or fields mentioned in this disclosure may be the average value, instantaneous value, maximum value, minimum value, etc. of the corresponding information and / or fields and / or parameters and / or values, and this disclosure does not limit them.

[0057] The information and / or fields described in this disclosure may be used to represent one or more of the following: up, down, up and down, up or down.

[0058] The information and / or fields described in this disclosure may be measured values ​​and / or actual values, or predicted values.

[0059] In this disclosure, a slice identifier can be represented by one or more Single Network Slice Selection Assistance Information (S-NSSAI).

[0060] In this disclosure, the TA received by the UE from the base station, the TA sent by the base station, the TA obtained through advance synchronization, and the TA in the LTM cell switching command can refer to each other.

[0061] In this disclosure, the TA calculated by the UE may also be referred to as the TA measured by the UE, the TA based on the UE, the TA based on the UE, the TA measurement based on the UE, etc.

[0062] In this document, the TCI status and / or beam information used when access to the target cell fails can refer to the TCI status and / or beam information used by the UE when access to the target cell fails, or it can refer to the TCI status and / or beam information used by the target cell node when access to the target cell fails. Similarly, the TCI status and / or beam information used when successfully accessing the target cell can refer to the TCI status and / or beam information used by the UE when successfully accessing the target cell, or it can refer to the TCI status and / or beam information used by the target cell node when successfully accessing the target cell. Furthermore, the TCI status and / or beam information used when (attempting) access to the target cell can refer to the TCI status and / or beam information used by the UE when (attempting) access to the target cell, or it can refer to the TCI status and / or beam information used by the target cell node when (attempting) access to the target cell. Other information fields (e.g., TA, etc.) have similar meanings and are not limited herein.

[0063] In this paper, the TCI status and / or beam information used when successfully accessing the target cell can be the TCI status and / or beam information used when successfully accessing the same (target) cell after a radio link failure, or the TCI status and / or beam information used after a successful handover and recovery from a beam failure in the same cell.

[0064] In this paper, the TA used when a UE successfully accesses the target cell can be the same TA used when a radio link failure occurs and the UE successfully accesses the same (target) cell. For example, successful access to the same (target) cell can be achieved through recovery and / or RRC re-establishment. Recovery can be fast recovery or LTM failure recovery, etc.

[0065] In this disclosure, fast recovery can be extended to one or more of the following: LTM failure recovery, beam failure recovery, RRC re-establishment, etc.

[0066] In this disclosure, TA expiration may also be referred to as TA expired and / or TA timeout, etc.

[0067] In this disclosure, the threshold can be any value. In some implementations, for example, the threshold can be 0.

[0068] The network self-optimization decisions described in this disclosure may include network energy saving, load balancing, coverage and / or capacity optimization, mobility (robustness) optimization and / or management, configuration formulation and / or updating, etc. Here, mobility robustness optimization and / or management may refer to optimization and / or management performed on the robustness of the UE's mobility.

[0069] In this disclosure, results and reports may refer to each other.

[0070] In this disclosure, time can be represented by one or more of the following: timestamp, point in time, time interval, timer, time period, time length, time cycle, time interval, duration, etc. The time length can be the time elapsed since a certain point in time, which can be the current moment or any other moment. The time can be relative or absolute. In some implementations, a time period can be represented by a separate field; for example, it can be a combination of start and end times, or a combination of start and time period.

[0071] In this disclosure, Quality of Experience (QoE) parameters and / or user experience parameters may include one or more of the following: Round-trip time, Jitter duration, Corruption duration, Average throughput, Initial playout delay, Playout Delay at InitialStartup, Device information, Rendered viewports, Codec information, Buffer level, Representation switch events, Play List, Media presentation description (MPD) information, Interactivity Summary, Interactivity Event List, etc.

[0072] In this disclosure, the Quality of Service (QoS) parameters may include at least one of the following: packet loss rate, latency, throughput, data rate, etc.

[0073] In this disclosure, load status and / or load information may include one or more of the following: PRB usage ratio, number of available PRBs, number of allocated PRBs, scheduling PDCCH CCE usage, Transport Network Layer (TNL) capacity indication, radio resource status, integrated available capacity group, integrated available resource group, number of active user terminals, number of Radio Resource Control (RRC) connections, slice available capacity, hardware capacity indication, S1 TNL load indication, hardware load indication, almost blank subframe (ABS) status, Reference Signal Received Power (RSRP) measurement report list, Reference Signal Received Quality (RSRQ) measurement report, Signal to Interference plus Noise Ratio (SINR) measurement report, Channel State Information (CSI) report, cell report indication, channel occupancy time ratio, energy detection. Detection threshold, signal strength and / or signal quality, channel busy ratio, data volume, and jitter of the above parameters, etc.

[0074] In this disclosure, load status and / or load information may refer to resource status.

[0075] In this disclosure, "beam" may refer to the SSB beam or any other beam.

[0076] In this disclosure, location can be represented by one or more of the following: coordinates, area, cell identifier, beam identifier, identifier for representing location and / or area, etc. The cell identifier can be one or more of the following: access cell identifier, connected cell identifier, serving cell identifier, etc. The beam identifier can be one or more of the following: access beam identifier, connected beam identifier, access beam identifier, etc. The identifier for representing location and / or area can be used to represent one or more locations and / or one or more areas. In some embodiments, for example, an area with a distance greater than and / or equal to and / or less than a specific threshold can be represented by an identifier. In other embodiments, for example, an area with a signal quality greater than and / or equal to and / or less than a specific threshold can be represented by an identifier.

[0077] In this disclosure, the target node can also be a candidate target node, a target master node, a target auxiliary node, a candidate target master node, a candidate target auxiliary node, etc.

[0078] In this disclosure, the source node can also be a source master node, a source slave node, etc.

[0079] In this disclosure, data collection can be Minimization of Drive Tests (MDT) or any other data collection method. This disclosure is not limited to any particular method. MDT can be a logged MDT or an immediate MDT. MDT can be a signaling-based MDT or a management-based MDT.

[0080] In this disclosure, collection may also be referred to as measurement.

[0081] In this disclosure, information can be actual values ​​collected and / or measured, predicted values, or generated values. Generated values ​​can be calculated values ​​obtained using mathematical methods, or generated and / or output values ​​obtained using artificial intelligence (AI) models, etc.

[0082] In this disclosure, data collection may be used to collect user trajectory information and / or user performance information, or for any other data collection.

[0083] In this disclosure, a secondary cell can be either a primary secondary cell (PSCell) or a secondary cell (SCell).

[0084] In this disclosure, the data collected may include one or more of the following:

[0085] • User trajectory-related data: This can include one or more of the following related to the user:

[0086] oUser ID

[0087] o Visiting cell identifier

[0088] o Accessing the main cell identifier

[0089] o Accessible secondary cell identifier

[0090] o Primary cell identifier and secondary cell identifier accessed: These indicate the primary and secondary cells accessed by the user in a dual-connectivity scenario.

[0091] o The node where the cell being accessed is located: can be either the node identifier or the node name. o The node where the primary cell being accessed is located: can be either the node identifier or the node name.

[0092] The node where the secondary cell is accessed can be either a node identifier or a node name.

[0093] o Visit time and / or stay time

[0094] o coordinate

[0095] o access beam information: could be beam identifier

[0096] • User performance-related data: This may include one or more of the following user-related data:

[0097] oUser ID

[0098] o User performance collection time

[0099] o The node corresponding to user performance: can be either a node identifier or a node name.

[0100] o User performance corresponding cell identifier

[0101] o User performance: may include one or more of the following: uplink and / or downlink data rate, uplink and / or downlink throughput, uplink and / or downlink latency, uplink and / or downlink packet loss rate, uplink and / or downlink QoE parameters

[0102] • User measurement result information: may include one or more of the following:

[0103] oUser ID

[0104] o Node identifier and / or cell identifier corresponding to user measurement results

[0105] o Measurement results

[0106] o Measurement time

[0107] In this disclosure, "beam" can refer to the Synchronization Signal and Physical Broadcast Channel (PBCH) block (SSB) beam, or any other beam.

[0108] In this disclosure, the L1 / L2 Triggered Mobility (LTM) cell handover can also be referred to as LTM handover.

[0109] In this disclosure, potential failure may refer to the possibility of failure.

[0110] In this disclosure, "near failure" can refer to a situation where, although no failure has occurred, there is a high probability that failure will happen. For example, a successful handover may be triggered, even though the handover was successful.

[0111] In this disclosure, the cause may also be referred to as a (report) type. For example, it may be a failure (report) type and / or a wireless link failure (report) type, a potential failure (report) type and / or a near failure (report) type and / or a successful handover (report) type, or a successful handover but with potential problems (report) type and / or a successful handover (report) type.

[0112] In this disclosure, access to (target) cell may also be referred to as handover to target cell and / or cell switching to target cell.

[0113] In this disclosure, when no handover occurs, such as a late handover, the source node can be the last serving node; when a handover occurs but fails, the source node can be the last serving node; when a handover succeeds but a radio link failure occurs, the target node can be the last serving node; and when a handover succeeds, the target node can be the last serving node. The term "node" can also refer to the cell and / or beam it manages.

[0114] In this disclosure, the target cell can be the last serving cell, the cell that the UE reconnects to, or the cell that the UE quickly restores its connection to.

[0115] In this disclosure, the Transmission Configuration Indicator (TCI) status may include one or more of the following: TCI status indication, beam identifier, cell identifier, node identifier, etc.

[0116] In this disclosure, beam information may include one or more of the following: TCI status (indication), beam identifier, cell identifier, node identifier, etc.

[0117] In this disclosure, LTM can also be extended to any other form of switching.

[0118] In this disclosure, cell switching and handover can refer to each other.

[0119] In this disclosure, user equipment (UE) can refer to user, terminal, etc.

[0120] In this disclosure, the model can be an artificial intelligence model and / or a machine learning model, a mathematical model, or any other model.

[0121] In this disclosure, collection can be used interchangeably with measurement.

[0122] In this disclosure, "related to" or "associated with" can also mean "including," and they can be used interchangeably. For example, "the first message related to / associated with the first information" can also mean "the first message including the first information," and so on.

[0123] The current self-optimization mechanism based on LTM is not perfect. In order to improve performance, an enhanced LTM self-optimization scheme is needed.

[0124] Example 1

[0125] This disclosure proposes a method to support mobility self-optimization, which may include: a first node sending a first message to a second node including information related to the availability of LTM cell transition information, so that the second node can know that the first node has LTM cell transition information.

[0126] In some implementations, the first message may include one or more of the following: RRC User Measurements Available, RRC Reestablishment Complete, RRC Reconfiguration Complete, RRC Resume Complete, or RRC Setup Complete; or another and / or newly defined MAC CE and / or RRC container and / or RRC and / or Xn and / or X2 and / or F1 and / or E1 and / or NG message. The first message may also be sent via MAC CE.

[0127] In some implementations, the first message may include one or more of the following fields:

[0128] • UE Identifier: Used to identify the UE corresponding to the available LTM cell transition information.

[0129] • Sending node identifier: Used to identify the node that sent the message.

[0130] • Receiver node identifier: Used to identify the node that received the message.

[0131] • Information related to the availability of LTM cell transition information: This field indicates that LTM cell transition information is available, meaning the message-sending node stores LTM cell transition information. This field can be represented by a single bit; for example, a bit of 1 indicates that LTM cell transition information is available, and a bit of 0 indicates that LTM cell transition information is not available. Alternatively, a bit of 0 indicates that LTM cell transition information is available, and a bit of 1 indicates that LTM cell transition information is not available. The LTM cell transition information can be referenced from the information in the third message.

[0132] • Specific information on available LTM cell switching information: The specific information can be found in the information in the third message.

[0133] In some implementations, the second node may send a second message containing a request for LTM cell transition information to the first node, based on its own circumstances and / or based on a first message received from the first node containing information related to the availability of LTM cell transition information, in order to request the first node to report LTM cell transition information.

[0134] In some implementations, the second message may be included in one or more of the following: a UE Information Request message for RRC; or another and / or a newly defined MAC CE and / or RRC container and / or RRC and / or Xn and / or X2 and / or F1 and / or E1 and / or NG message.

[0135] In some implementations, the second message may include one or more of the following fields:

[0136] • UE Identifier: Used to identify the UE corresponding to the requested LTM cell transition information.

[0137] • Sending node identifier: Used to identify the node that sent the message.

[0138] • Receiver node identifier: Used to identify the node that received the message.

[0139] • LTM Cell Transition Information Request: This field indicates a request for LTM cell transition information. It can be represented by a single bit; for example, a bit of 1 indicates a request for LTM cell transition information, and a bit of 0 indicates no request. Alternatively, a bit of 0 can indicate a request for LTM cell transition information, and a bit of 1 can indicate no request. The LTM cell transition information can be referenced from the information in the third message.

[0140] • Information requested to be collected and / or reported: The information requested to be collected and / or reported may refer to the information in the third message.

[0141] Example 2

[0142] This disclosure proposes a method to support mobility self-optimization, which may include: a first node sending a third message containing LTM cell transition information to a second node, so that the second node can obtain LTM cell transition information related to one or more UEs.

[0143] The second node can perform self-optimization based on the received LTM cell transition information. For example, the second node can perform mobility robustness optimization based on the received LTM cell transition information. For instance, LTM cell transition information can be used by the second node to analyze the causes of LTM-related radio link failures and / or potential failures and / or near-failures, and to perform related self-optimization. LTM cell transition information can also be used by the second node to analyze whether the problem originates from itself or other nodes when analyzing radio link causes, and to perform related self-optimization. LTM cell transition information can also be forwarded by the second node to other nodes for them to analyze failure causes and perform related self-optimization. This scheme can optimize mobility robustness to ensure mobility robustness and reduce and / or avoid failures. In this disclosure, failure can refer to radio link failure, handover failure, potential radio link failure, potential handover failure, near-radio link failure, near-handover failure, etc.

[0144] The aforementioned second node or other nodes can be one or more of the following: target node, target node CU, target node DU, source node, source node CU, source node DU, last service node CU, and last service node DU.

[0145] In some implementations, the third message may include one or more of the following: RRC UE Information Response, Secondary Cell Group Failure Information (SCGFailure Information), Primary Cell Group Failure Information (MCGFailure Information); Xn's FAILURE INDICATION message, HANDOVER REPORT message, ACCESS AND MOBILITY INDICATION message, S-NODE MODIFICATION REQUEST message, SgNB MODIFICATION REQUEST message, SCG FAILURE INFORMATION REPORT message, RRC TRANSFER message; F1's ACCESS AND MOBILITY INDICATION message, DU-CU ACCESS AND MOBILITY INDICATION message; NG's UPLINK RAN CONFIGURATION. Downlink RAN ​​Configuration Forwarding (DRIF) message, or a new and / or newly defined MAC CE and / or RRC container and / or RRC and / or Xn and / or X2 and / or F1 and / or E1 and / or NG message. This information or message may be included in a report, which may be a Connection Establishment Failure (CEF) report, a Random Access report, a Successful Handover report, a Radio Link Failure (RLF) report, a measurement report, or other reports related to wireless connectivity.

[0146] In some implementations, if the first node is a UE, the UE can record and / or report relevant information of a third message in the relevant report. For example, when a radio link failure occurs, the relevant report may be a radio link failure report and / or a random access report. For example, when a handover is successful, but the triggering conditions for a successful handover report are met, the relevant report may be a successful handover report.

[0147] In some implementations, the third message may include one or more of the following fields:

[0148] • UE Identifier: Used to identify the UE corresponding to LTM cell transition information. This UE identifier can include any identifier, such as one or more of the following: source node and / or target node UE XnAP ID, node UE XnAPID, gNB DU and / or gNB CU UE F1AP ID, and the C-RNTI assigned to the source node and / or target node. The source node can include one or more of the following: source node CU, source node DU, source node CUCP, source node CUUP, source node, etc. The target node can include one or more of the following: target node CU, target node DU, target node CUCP, target node CUUP, target node, etc.

[0149] • Cell Identifier: Used to identify the cell corresponding to LTM cell transition information. It may include one or more of the following: target cell identifier, source cell identifier, last serving cell identifier, etc.

[0150] • Node Identifier: Used to identify the node corresponding to LTM cell transition information. It may include one or more of the following: target node identifier, source node identifier, last serving node identifier, etc.

[0151] • Beam identifier: Used to identify the beam corresponding to LTM cell transition information. It may include one or more of the following: the beam identifier of the target cell, the beam identifier of the source cell, the beam identifier of the last serving cell, etc.

[0152] • Information related to the timing advance (TA) acquisition method: This can be used to indicate the TA acquisition method used by the UE.

[0153] The acquisition method of TA may include one or more of the following: calculated by the UE (also known as measured by the UE, UE-based, etc.), received by the UE from the base station (also known as sent by the base station), obtained through random access (contention-based and / or contention-free), etc.

[0154] The TA can be one or more of the following: the TA used by the UE when it attempts to access the target cell, the TA used when the UE fails to access the target cell, and the TA used when the UE successfully accesses the target cell.

[0155] If the message sending node is a UE, and the TA (Target Access Transaction) for accessing the target cell is calculated and / or measured by the UE, the UE can record and / or report in the relevant report that the TA for accessing the target cell is calculated and / or measured by the UE. If the message sending node is a UE, and the TA for accessing the target cell is received from the base station (e.g., from an LTM cell handover command sent by the base station), the UE can record and / or report in the relevant report that the TA for accessing the target cell is received from the base station. If the message sending node is a UE, and the TA for accessing the target cell is obtained through random access (based on contention and / or without contention), the UE can record and / or report in the relevant report that the TA for accessing the target cell is obtained through random access (based on contention and / or without contention). For example, when a radio link failure occurs, the relevant report could be a radio link failure report and / or a random access report. For example, when a handover is successful, but the triggering conditions for a successful handover report are met, the relevant report could be a successful handover report.

[0156] If the message sending node is a base station, when sending a TA (Target Access Request) for accessing the target cell to the UE, the message sending node may send information related to the acquisition method of the TA, which may indicate that the TA was sent by the base station. If the message sending node is a base station, when the TA for the UE to access the target cell is calculated and / or measured by the UE, the message sending node may send information related to the acquisition method of the TA, which may indicate that the TA was calculated and / or measured by the UE. If the message sending node is a base station, when the TA for the UE to access the target cell is obtained through random access (based on contention and / or without contention), the message sending node may send information related to the acquisition method of the TA, which may indicate that the TA was obtained through random access (based on contention and / or without contention).

[0157] The message receiving node can perform self-optimization based on this information, for example, mobility robustness optimization. In some implementations, for example, when it is found that the reason for the UE's failure to access the target cell is that the TA is invalid, if the TA used by the UE to access the target cell was received from the base station, the node can perform optimization, for example, optimizing the maintenance of the TA's validity period (e.g., reducing the validity period of the TA or any other implementation that can prevent the base station from sending invalid TAs to the UE). For example, when it is found that the reason for the UE's failure to access the target cell is that the TA is invalid, if the TA used by the UE to access the target cell was calculated by the UE, the node may not perform optimization. Alternatively, the node may no longer allow and / or configure the UE to use the TA calculated by the UE to access the target cell. Or, the node may not send this information to other nodes for related optimization (e.g., not sending this information to the corresponding source node and / or last serving node (e.g., source node and / or source node CU and / or source node DU and / or last serving node CU and / or last serving node DU) for related optimization).

[0158] For example, when it is found that the reason for the UE's failure to access the target cell is the failure of the TA, if the TA used by the UE to access the target cell is obtained through random access (based on contention and / or without contention), the node may not perform optimization. Alternatively, the node may send the information to the corresponding node (e.g., the target node and / or the target node CU and / or the target node DU and / or the source node and / or the source node CU and / or the source node DU and / or the last serving node CU and / or the last serving node DU) for the corresponding node to optimize the calculation of the TA and / or the random access process. Alternatively, the node may not send the information to other nodes for related optimization (e.g., not sending the information to the corresponding source node and / or the last serving node (e.g., the source node and / or the source node CU and / or the source node DU and / or the last serving node CU and / or the last serving node DU) for related optimization).

[0159] • TA used when successfully accessing the target cell: This indicates the TA used by the UE when successfully accessing the target cell. If the UE fails to access the target cell (the failure could be a radio link failure, etc.), and the UE reconnects to the same cell and / or performs fast recovery to the same cell, the TA used for successful access to the target cell is the TA used by the UE when reconnecting to the same cell and / or performing fast recovery to the same cell. When the message sending node is the UE, the UE can record the TA used when successfully accessing the target cell in the corresponding report. This report can be a radio link failure report or a random access report, etc. The message receiving node can perform self-optimization based on this information, for example, mobility robustness optimization. For example, the message receiving node can optimize based on the TA used when the UE successfully accessed the target cell and / or the TA used when the UE failed to access the target cell. For example, if the difference between the TA used when the UE successfully accessed the target cell and the TA used when the UE failed to access the target cell is too large (e.g., greater than and / or equal to a specific threshold) and / or inconsistent, it can be indicated that the cause of the failure may be the invalidation of the TA used when the UE failed to access the target cell. Nodes can optimize the maintenance of the validity period of the TA (Target Access Term). For example, the source node can optimize the maintenance of the validity period of the TA to ensure that the TA sent to the UE for accessing the target cell and / or the TA calculated by the UE for accessing the target cell when handover and / or cell switching are triggered are valid, thereby avoiding failures and ensuring mobility robustness. The TA can be obtained through a contention-based and / or contention-free random access procedure, or it can be the TA calculated by the UE, or it can be the TA received by the UE from the base station.

[0160] • TA used when access to the target cell fails: This refers to the TA used by the UE when access to the target cell fails during handover and / or cell transition. If the UE fails to access the target cell due to the inability to utilize the TA (such as a radio link failure), the TA used when accessing the target cell fails is the TA used when the UE fails to access the target cell due to the inability to utilize the TA (such as a radio link failure). When the message sending node is the UE, the UE will record the TA used when accessing the target cell fails during handover and / or cell transition in the corresponding report. This report can be a radio link failure report or a random access report, etc. The TA can be calculated and / or measured by the UE, or it can be received from the base station (also referred to as being sent by the base station). The message receiving node can perform self-optimization based on this information, for example, mobility robustness optimization. For example, the message receiving node can optimize based on the TA used when the UE successfully accesses the target cell and the TA used when the UE fails to access the target cell. For example, if the difference between the TA used when the UE successfully accesses the target cell and the TA used when the UE fails to access the target cell is too large (e.g., greater than and / or equal to a specific threshold) and / or inconsistent, it can be concluded that the failure may be due to the invalidation of the TA used when the UE failed to access the target cell. Nodes can optimize the maintenance of the TA's validity period. For example, the source node can optimize the maintenance of the TA's validity period to ensure that the TA sent to the UE for accessing the target cell and / or the TA calculated by the UE for accessing the target cell when triggering handover and / or cell transition is valid, thereby avoiding failure and ensuring mobility robustness. The TA can be obtained through a contention-based and / or contention-free random access procedure, or it can be the TA calculated by the UE, or it can be the TA received by the UE from the base station. If the TA is received by the UE from the base station, it can also be called the pre-synchronized TA, the TA sent by the base station, or the TA in the LTM cell transition command.

[0161] The difference between the TA used when the UE fails to access the target cell and the TA used when the UE successfully accesses the target cell: This represents the difference between the TA used when the UE fails to access the target cell during handover and / or cell transition and the TA used when the UE successfully accesses the target cell. If the UE fails to access the target cell (the failure could be a radio link failure, etc.) and reconnects to the same cell and / or performs fast recovery to the same cell, the TA used when the UE fails to access the target cell is the same as the TA used when the UE fails to access the target cell (the failure could be a radio link failure, etc.), and the TA used when the UE successfully accesses the target cell is the same as the TA used when the UE reconnects to the same cell and / or performs fast recovery to the same cell. When the message sending node is the UE, the UE can record the difference between the TA used when the UE fails to access the target cell and the TA used when the UE successfully accesses the target cell in the corresponding report. This report can be a radio link failure report or a random access report, etc. The message receiving node can perform self-optimization based on this information, for example, mobility robustness optimization. For example, if the TA used when the UE fails to access the target cell differs significantly (e.g., greater than and / or equal to a specific threshold) and / or is inconsistent with the TA used when the UE successfully accesses the target cell, it can be concluded that the failure may be due to the invalidation of the TA used when the UE failed to access the target cell. Nodes can optimize the maintenance of the TA's validity period. For example, the source node can optimize the maintenance of the TA's validity period to ensure that the TA sent to the UE for accessing the target cell and / or the TA calculated by the UE for accessing the target cell when triggering handover and / or cell transition are valid, thereby avoiding failures and ensuring mobility robustness. The TA can be obtained through a contention-based and / or contention-free random access procedure.

[0162] It can be the TA calculated by the UE, or it can be the TA received by the UE from the base station.

[0163] • TA (Track Access) used to access the target cell: This indicates the TA used by the UE to access the target cell. In some implementations, for example, the UE may record and / or report the TA used by the UE to access the target cell in relevant reports. For example, when a radio link failure occurs, the relevant report may be a radio link failure report and / or a random access report. For example, when a handover is successful, but the triggering condition for a successful handover report is met, the relevant report may be a successful handover report. In some implementations, for example, this information may be used for node self-optimization. For example, the node may optimize based on the TA used by the UE to access the target cell and / or the TA used when the UE successfully accessed the target cell. For example, when the difference between the TA used by the UE to access the target cell and the TA used when the UE successfully accessed the target cell is large (e.g., greater than and / or equal to a specific threshold), it may indicate that the cause of the radio link failure and / or the potential cause of failure and / or the near-failure is TA failure, and / or it may indicate that the cause of failure is the failure of the TA used when the UE failed to access the target cell. The node may optimize the maintenance of the TA's validity period. For example, the source node can optimize the validity period maintenance of the TA (Target Access Transaction) to ensure that the TA sent to the UE for accessing the target cell and / or the TA calculated by the UE for accessing the target cell when triggering handover and / or cell switching are valid, thereby avoiding failures and ensuring mobility robustness. The TA can be obtained through a contention-based and / or contention-free random access procedure, or it can be a TA calculated by the UE, or it can be a TA received by the UE from the base station. If the TA is received by the UE from the base station, it can also be called a pre-synchronized TA, a TA sent by the base station, or the TA in the LTM cell switching command.

[0164] The difference between the TA used by the UE (attempting) to access the target cell and the TA used when the UE successfully accessed the target cell: This represents the difference between the TA used by the UE (attempting) to access the target cell and the TA used when the UE successfully accessed the target cell. In some implementations, for example, the UE may record and / or report the difference between the TA used by the UE (attempting) to access the target cell and the TA used when the UE successfully accessed the target cell in relevant reports. For example, when a radio link failure occurs, the relevant report may be a radio link failure report and / or a random access report. For example, when a successful handover occurs, but the triggering condition for a successful handover report is met, the relevant report may be a successful handover report. In some implementations, for example, this information may be used for node self-optimization. For example, when the difference between the TA used by the UE (attempting) to access the target cell and the TA used when the UE successfully accessed the target cell is large (e.g., greater than and / or equal to a specific threshold), it may indicate that the cause of the radio link failure and / or the potential cause of failure and / or the near-failure is TA failure, and / or it may indicate that the cause of failure may be the failure of the TA used when the UE failed to access the target cell. The node may optimize the maintenance of the TA's validity period. For example, the source node can optimize the validity period maintenance of the TA (Target Access Transaction) to ensure that the TA sent to the UE for accessing the target cell and / or the TA calculated by the UE for accessing the target cell when handover and / or cell transition are triggered are valid, thereby avoiding failures and ensuring mobility robustness. The TA can be obtained through a contention-based and / or contention-free random access procedure, or it can be...

[0165] The TA calculated by the UE can also be the TA received by the UE from the base station.

[0166] • Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell: This indicates the TCI status and / or beam information used by the UE when successfully accessing the target cell. The beam information can be the identifier and / or list of identifiers of the beams used by the UE when successfully accessing the target cell. The TCI status and / or beam can be the TCI status and / or beam used by the UE to send and / or receive messages and / or data, or it can be the TCI status and / or beam used by the base station to receive and / or send messages and / or data. If a UE fails to access the target cell (the failure could be a radio link failure, etc.) and / or fails after accessing the target cell (the failure could be a radio link failure, etc.), and the UE reconnects to the same cell and / or performs fast recovery and / or beam failure recovery to reconnect to the same cell, the Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell are the TCI status and / or beam information used by the UE when reconnecting to the same cell and / or performing fast recovery and / or beam failure recovery to reconnect to the same cell. When the message sending node is the UE, the UE can record the TCI status and / or beam information used when successfully accessing the target cell in the corresponding report. This report can be a radio link failure report or a random access report, etc. The message receiving node can perform self-optimization based on this information, for example, mobility robustness optimization. For example, the message receiving node can perform optimization based on the TCI status and / or beam information used when successfully accessing the target cell and the TCI status and / or beam information used when accessing the target cell fails. For example, if the TCI state and / or beam information used when successfully accessing the target cell differs significantly (e.g., greater than and / or equal to a specific threshold) and / or is inconsistent with the TCI state and / or beam information used when access to the target cell fails, it can be concluded that the failure was due to an error in the TCI state and / or beam information used when the UE failed to access the target cell. The node can optimize the TCI state and / or beam to avoid failures and ensure mobility robustness. In this disclosure, the difference in TCI state can refer to the difference in the TCI state identifier, and the difference in beam can refer to the difference in the beam identifier.

[0167] • TCI status and / or beam information used when access to the target cell fails: This indicates the TCI status and / or beam information used by the UE when access to the target cell fails during handover and / or cell transition. Beam information can be the beam (identifier and / or list of identifiers) used by the UE when successfully accessing the target cell. The TCI status and / or beam can be the TCI status and / or beam used by the UE to send and / or receive messages and / or data, or it can be the TCI status and / or beam used by the base station to receive and / or send messages and / or data.

[0168] If a UE fails to access the target cell due to the inability to utilize TCI status and / or beam information (the failure could be a radio link failure, etc.) and / or fails after accessing the target cell (the failure could be a radio link failure, etc.), the TCI status and / or beam information used when accessing the target cell fails are the TCI status and / or beam information used by the UE when accessing the target cell fails due to the inability to utilize TCI status and / or beam information (the failure could be a radio link failure, etc.) and / or fails after accessing the target cell (the failure could be a radio link failure, etc.). When the message sending node is the UE, the UE will record the TCI status and / or beam information used when accessing the target cell fails during handover and / or cell transition in the corresponding report. This report can be a radio link failure report or a random access report, etc. The message receiving node can perform self-optimization based on this information, for example, mobility robustness optimization. For example, optimization can be performed based on the TCI status and / or beam information used when successfully accessing the target cell and the TCI status and / or beam information used when accessing the target cell fails. For example, if the TCI state and / or beam information used when successfully accessing the target cell differs significantly (e.g., greater than and / or equal to a specific threshold) and / or is inconsistent with the TCI state and / or beam information used when access to the target cell fails, it indicates that the failure may be due to an error in the TCI state and / or beam information used when the UE failed to access the target cell. The node can optimize the TCI state and / or beam to avoid failures and ensure mobility robustness.

[0169] • The difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell: This represents the difference between the TCI status and / or beam information used by the UE when accessing the target cell fails during handover and / or cell transition and the TCI status and / or beam information used by the UE when successfully accessing the target cell. If a UE fails to access the target cell (the failure could be a radio link failure, etc.) and / or fails after accessing the target cell (the failure could be a radio link failure, etc.), and the UE reconnects to the same cell and / or performs fast recovery and / or beam failure recovery to reconnect to the same cell, the TCI status and / or beam information used when accessing the target cell fails are the same as those used when the UE fails to access the target cell (the failure could be a radio link failure, etc.) and / or fails after accessing the target cell (the failure could be a radio link failure, etc.). The TCI status and / or beam information used when successfully accessing the target cell can be the same as those used when the UE reconnects to the same cell and / or performs fast recovery and / or beam failure recovery to reconnect to the same cell. When the message sending node is the UE, the UE can record the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell in the corresponding report. The report can be a radio link failure report or a random access report, etc. The message receiving node can perform self-optimization based on this information, such as mobility robustness optimization. For example, if the TCI state and / or beam information used when accessing the target cell fails differs significantly (e.g., greater than and / or equal to a specific threshold) and / or is inconsistent with the TCI state and / or beam information used when successfully accessing the target cell, it indicates that the failure may be due to an error in the TCI state and / or beam used when the UE failed to access the target cell. The node can optimize the TCI state and / or beam to avoid failures and ensure mobility robustness.

[0170] • TCI status and / or beam information used for (attempted) access to the target cell: This indicates the TCI status and / or beam information used for (attempted) access to the target cell. In some implementations, for example, the UE may record and / or report the TCI status and / or beam information used for (attempted) access to the target cell in a relevant report. For example, when a radio link failure occurs, the relevant report may be a radio link failure report and / or a random access report. For example, when a handover is successful, but the triggering condition for a successful handover report is met, the relevant report may be a successful handover report. In some implementations, for example, this information may be used for node self-optimization. For example, the node may optimize based on the TCI status and / or beam information used for (attempted) access to the target cell and / or the TCI status and / or beam information used when successfully accessing the target cell. The target cell for (attempted) access and the target cell for successful access may be the same cell. The access may be the access of the same UE.

[0171] For example, if the difference between the TCI state and / or beam information used when attempting to access the target cell and the TCI state and / or beam information used when successfully accessing the target cell is large (e.g., greater than and / or equal to a specific threshold), it can be indicated that the cause of the radio link failure and / or potential failure and / or near-failure is an error in the TCI state and / or beam information, and / or it can be indicated that the cause of failure may be an error in the TCI state and / or beam information used when the UE failed to access the target cell. The message receiving node can perform self-optimization based on this information, for example, mobility robustness optimization. For example, if the difference between the TCI state and / or beam information used when accessing the target cell fails and the TCI state and / or beam information used when successfully accessing the target cell is too large (e.g., greater than and / or equal to a specific threshold) and / or inconsistent, it can be indicated that the cause of failure may be an error in the TCI state and / or beam information used when the UE failed to access the target cell. The node can optimize the TCI state and / or beam to avoid failure and ensure mobility robustness.

[0172] The difference between the TCI state and / or beam information used when attempting to access the target cell and the TCI state and / or beam information used when successfully accessing the target cell: This represents the difference between the TCI state and / or beam information used by the UE during handover and / or cell transition when attempting to access the target cell and the TCI state and / or beam information used when successfully accessing the target cell. The target cell attempted to access and the target cell successfully accessed can be the same cell. The access can be accessed by the same UE. In some implementations, for example, the UE can record and / or report the difference between the TCI state and / or beam information used when attempting to access the target cell and the TCI state and / or beam information used when successfully accessing the target cell in relevant reports. For example, when a radio link failure occurs, the relevant report can be a radio link failure report and / or a random access report. For example, when a handover is successful, but the triggering condition for a successful handover report is met, the relevant report can be a successful handover report. For example, if the difference between the TCI state and / or beam information used when attempting to access the target cell and the TCI state and / or beam information used when successfully accessing the target cell is large (e.g., greater than and / or equal to a specific threshold), it can be indicated that the cause of the radio link failure and / or potential failure and / or near-failure is an error in the TCI state and / or beam information, and / or it can be indicated that the cause of failure may be an error in the TCI state and / or beam information used when the UE failed to access the target cell. The message receiving node can perform self-optimization based on this information, for example, performing mobility robustness optimization.

[0173] • Information related to the simultaneous configuration and / or simultaneous existence of conditional switching and LTM: This information indicates that the UE has been simultaneously configured with conditional switching and LTM. For example, this information may include one or more of the following: an indication that conditional switching and LTM are simultaneously configured and / or coexist, conditional switching configuration, LTM configuration, etc. The LTM configuration can refer to the LTM configuration described below. The conditional switching configuration can refer to the conditional switching configuration described below. If the message sending node is a UE, when the UE is simultaneously configured with conditional switching and LTM, the UE can record and / or... in the relevant report.

[0174] Alternatively, it may report information related to the simultaneous configuration and / or simultaneous existence of conditional handover and LTM. For example, when a radio link failure occurs, the relevant report could be a radio link failure report and / or a random access report. For example, when a handover is successful, but the triggering conditions for a successful handover report are met, the relevant report could be a successful handover report. If the message sending node is a base station, it sends this information when conditional handover and LTM are configured simultaneously for the UE.

[0175] The message receiving node can perform self-optimization based on this information, for example, mobility robustness optimization. In some implementations, for example, when the cause of radio link failure and / or the cause of potential failure and / or the cause of near failure is late handover and / or late cell transition, the node needs to optimize conditional handover, and / or the node needs to optimize LTM. Alternatively, when the cause of radio link failure and / or the cause of potential failure and / or the cause of near failure is late handover and / or late cell transition, the last serving node and / or the last serving node CU and / or the source node and / or the source node CU need to optimize conditional handover, and / or the last serving node and / or the last serving node CU and / or the source node and / or the source node CU and / or the source node DU need to optimize LTM. If LTM is triggered by the last serving node and / or the last serving node CU and / or the source node and / or the source node CU, the last serving node and / or the last serving node CU and / or the source node and / or the source node CU optimize LTM. If LTM is triggered by the last serving node and / or the last serving node DU and / or the source node DU, the last serving node and / or the last serving node DU and / or the source node and / or the source node DU optimize the LTM. If LTM is triggered by the last serving node and / or the last serving node DU and / or the source node and / or the source node DU, after receiving LTM cell transition information, the last serving node and / or the last serving node CU and / or the source node and / or the source node CU need to send the LTM cell transition information to the last serving node DU and / or the source node DU for related optimization. In some implementations, for example, when the cause of radio link failure and / or the cause of potential failure and / or the cause of near failure is premature handover and / or premature cell transition and / or handover to the wrong cell, and when the handover and / or cell transition performed by the UE is a conditional handover, the source node and / or the source node CU need to perform corresponding optimizations. Alternatively, the source node and / or source node CU can send relevant information to source node DU, which can then use the received information as reference and / or not perform optimization. In some implementations, for example, when the cause of radio link failure and / or the cause of potential failure and / or the cause of near failure is premature handover and / or premature cell transition and / or handover to the wrong cell, and when the handover and / or cell transition performed by the UE is an LTM cell transition, the source node and / or source node CU and / or source node DU need to perform corresponding optimizations. For example, when the cell transition time and / or the target cell of the cell transition is selected by the CU, the source node and / or source node CU need to perform corresponding optimizations. For example, when the cell transition time and / or the target cell of the cell transition is selected by the DU, the source node and / or source node DU perform corresponding optimizations.In other words, when the cell handover time and / or the target cell for cell handover is selected by the DU, the source node and / or source node CU need to send relevant information to the source node DU, and the source node DU will perform corresponding optimizations.

[0176] Alternatively, after receiving the relevant information, the source node and / or the source node CU may use the relevant information as reference information and / or not perform optimization. The relevant information may include the following:

[0177] One or more: Report type, self-optimization report, LTM cell transition information, etc. • Type of handover and / or cell transition: Indicates the type of handover and / or cell transition performed.

[0178] The types may include one or more of the following: conditional switching, LTM, layer 3 switching, dual-active protocol stack (DAPS) switching, etc.

[0179] • LTM configuration: This may include one or more of the following: (candidate) target cell identifier and / or cell list, reference configuration, CSI resource configuration, (contention-free) random access resource configuration, advance synchronization resource configuration, advance synchronization (candidate) cell information, UE-based TA measurement configuration, mapping (list) of LTM configuration identifier and cell identifier, etc. The advance synchronization (candidate) cell information may include one or more of the following: cell identifier, TCI status configuration, advance uplink synchronization configuration, advance uplink synchronization configuration for Supplementary uplink (SUL), TA assistance information, UE-based TA measurement configuration, etc.

[0180] This information can be used by the node to optimize the corresponding configuration. After the node releases the UE's context, this information can be used to optimize the corresponding configuration (e.g., the LTM configuration) to prevent the node from optimizing for inappropriate configurations (e.g., other LTM configurations or others).

[0181] Optimization during switching configurations can lead to unnecessary and / or erroneous optimizations. • Conditional handover configurations: may include one or more of the following: (candidate) target cell identifier,

[0182] The execution conditions corresponding to the (candidate) target cell, and the slices supported by the (candidate) target cell.

[0183] Protocol Data Units (PDUs) accepted by the (candidate) target cell

[0184] Information such as PDU session (resource) details. The PDU session (resource) details accepted by the (candidate) target cell may include one or more of the following: PDU session identifier, number of accepted PDU sessions (resources), etc. In some implementations, for example, if the UE is (simultaneously) configured with conditional handover and LTM, the conditional handover configuration needs to be added. This conditional handover configuration can be used by the node to optimize the handover, for example, it can be used by the node to optimize the configuration of conditional handover and / or LTM to improve mobility robustness. This information can be used by the node to optimize the corresponding configuration. After the node releases the UE's context, this information can be used by the node to optimize the corresponding configuration (e.g., the conditional handover configuration) to prevent the node from optimizing the configuration that does not correspond (e.g., other conditional handover configurations or others).

[0185] Optimization of handover configuration may lead to unnecessary and / or erroneous optimizations. Information related to the triggering of handover and / or cell transitions: This information can be used to indicate the triggering of UE handover and / or cell transitions. The triggering of UE handover and / or cell transitions may include one or more of the following: Layer 1 (measurement results) triggered handover and / or cell transition, Layer 3 (measurement results) triggered handover and / or cell transition, CU triggered handover and / or cell transition, DU triggered handover and / or cell transition based on Layer 3 measurement results triggered by CU, CU triggered handover and / or cell transition based on Layer 1 measurement results triggered by CU, DU triggered handover and / or cell transition based on Layer 3 measurement results triggered by DU, DU triggered handover and / or cell transition based on Layer 1 measurement results, etc. The message receiving node can perform self-optimization based on this information, for example, mobility robustness optimization. In some implementations, for example, if the handover and / or cell transition is triggered by CU, the source node and / or the source node CU performs self-optimization, and / or the source node CU does not need to send relevant information to the source node DU. In another implementation, for example, if the handover and / or cell transition is triggered by the DU, the source node DU performs self-optimization. That is, if the handover and / or cell transition is triggered by the DU, the source node and / or source node CU need to send relevant information to the source node DU, and the source node DU performs self-optimization. The relevant information may include...

[0186] The next one or more: report type, self-optimization report, LTM cell transition related information, etc. • Layer 1 measurement results: used to record Layer 1 measurement results before and / or during and / or after handover and / or before and / or during and / or after failure and / or when and / or after re-accessing the cell. This information may include one or more of the following: cell identifier, frequency information corresponding to the measurement result, beam information corresponding to the measurement result, measurement result, measurement identifier, etc. The measurement result can also be the difference between measurement results corresponding to any two times before and / or during and / or after handover and / or before and / or during and / or after failure and / or when and / or after re-accessing the cell. In some implementations, for example, a node can use this information to determine whether the target node for the handover has been correctly selected. In other implementations, for example, a node can use this information to determine whether the reason a user cannot access the network using the TA obtained through pre-synchronization is due to TA failure. For example, if the Layer 1 measurement result obtained during pre-synchronization (i.e., the TA in the LTM cell transition command) differs significantly from the Layer 1 measurement result during actual access (e.g., large...), the node may determine whether the TA is faulty.

[0187] If the threshold is equal to or greater than a certain threshold, it indicates that the inability to access the network is due to a TA failure. Layer 3 measurement results: These are used to record Layer 3 measurement results before and / or during and / or after handover and / or before and / or during and / or after failure and / or when and / or after re-accessing the cell. This information may include one or more of the following: cell identifier, frequency information corresponding to the measurement result, beam information corresponding to the measurement result, measurement result, measurement identifier, etc. The measurement result can also be the difference between measurement results at any two times: before and / or during and / or after handover and / or before and / or during and / or after failure and / or when and / or after failure and / or when and / or after re-accessing the cell. In some implementations, for example, a node can use this information to determine whether the target node for the handover has been correctly selected. In other implementations, for example, a node can use this information to determine whether the reason the user cannot access the network using the TA obtained through pre-synchronization is due to a TA failure. For example, if the TA obtained through pre-synchronization (i.e., the TA in the LTM cell transition command) is invalid...

[0188] If the difference between the Layer 1 measurement result at the time of access and the Layer 1 measurement result at the actual access time is too large (e.g., greater than and / or equal to a certain threshold), it can indicate that the reason for the inability to access is that the TA in the LTM command is invalid.

[0189] • Reason: This can be a reason for failure, a potential reason for failure, or a reason for near-failure, or a reason for a successful handover but with potential problems. The reason may include one or more of the following: beam information error, TCI status information error, TA failure, TA inapplicable, TA sent by the base station to the UE failure, TA sent by the base station to the UE inapplicable, TA calculated by the UE failure, TA calculated by the UE inapplicable, etc. This reason may be referred to as (report).

[0190] Type. For example, it could be a failure (report) type and / or a wireless link failure (report).

[0191] The type can be a potential failure (report) type and / or a near failure (report) type and / or a successful switchover (report) type, or a successful switchover but with potential problems (report) type and / or a successful switchover (report) type.

[0192] Based on the above information, nodes can determine the cause of failure and / or potential causes of failure and / or reasons that are close to failure. For example:

[0193] • Beam information error and / or TCI status information error: For example, this reason can be determined based on one or more of the following information: the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when (attempting) accessing the target cell, the difference between the TCI status and / or beam information used when (attempting) accessing the target cell and the TCI status and / or beam information used when successfully accessing the target cell, Layer 1 measurement results, Layer 3 measurement results, etc. For example, a failure occurs when a UE attempts to access a target cell based on (e.g., TCI status and / or beam information received from a base station), and / or a failure occurs after a UE attempts to access a target cell based on (e.g., TCI status and / or beam information received from a base station), and the UE then reconnects using new TCI status and / or beam information (e.g., via LTM fast recovery and / or RRC reconstruction and / or beam failure recovery) to the same cell (i.e., the aforementioned target cell where the failure occurred), wherein the UE attempts to access the target cell based on (e.g., TCI status and / or beam information received from a base station)... The TCI state and / or beam information corresponding to the failure to access the target cell and / or the subsequent failure after accessing the target cell are the TCI state and / or beam information used when accessing the target cell failed and / or the TCI state and / or beam information used when (attempting) accessing the target cell. The TCI state and / or beam information corresponding to the UE reconnecting to the same cell using the new TCI state and / or beam information (e.g., through LTM fast recovery and / or RRC reconstruction and / or beam failure recovery) is the TCI state and / or beam information used when successfully accessing the target cell. For example, if the difference between the TCI state and / or beam information used when accessing the target cell failed and the TCI state and / or beam information used when successfully accessing the target cell is too large (e.g., greater than and / or equal to a specific threshold) and / or inconsistent, the reason can be considered as beam information error and / or TCI state information error. The target cell where access failed and the target cell where access was successfully accessed can be the same cell. For example, if the difference between the TCI status and / or beam information used when (attempting) to access the target cell and the TCI status and / or beam information used when successfully accessing the target cell is too large (e.g., greater than and / or equal to a specific threshold) and / or inconsistent, the cause can be considered to be incorrect beam information and / or incorrect TCI status information. The target cell (attempting) to access and the target cell (successfully accessed) can be the same cell.For example, if the difference between the TCI status and / or beam information used when access to the target cell fails and the TCI status and / or beam information used when accessing the target cell successfully is too large (e.g., greater than and / or equal to a specific threshold) and / or inconsistent, the cause can be considered an error in beam information and / or TCI status information. The target cell where access failed and the target cell where access was successfully accessed can be the same cell. Alternatively, the node can determine the cause based on Layer 1 measurement results and / or Layer 3 measurement results. For example, the node can determine whether the TCI status information and / or beam information provided to the UE is correct based on Layer 1 measurement results and / or Layer 3 measurement results. The "too large difference" can mean a difference greater than and / or equal to a specific threshold. The above can also be the definition and / or concept of beam information error and / or TCI status information error.

[0194] • TA invalid and / or TA inapplicable and / or TA sent by the base station to the UE invalid and / or TA sent by the base station to the UE inapplicable and / or TA calculated by the UE invalid and / or TA calculated by the UE inapplicable:

[0195] For example, the cause can be determined based on one or more of the following information: the TA used when the UE successfully accesses the target cell, the TA used when the UE fails to access the target cell, the difference between the TA used when the UE fails to access the target cell and the TA used when the UE successfully accesses the target cell, the TA used by the UE (attempting) to access the target cell, the difference between the TA used by the UE (attempting) to access the target cell and the TA used when the UE successfully accesses the target cell, Layer 1 measurement results, Layer 3 measurement results, etc. For example, when a UE fails to access a target cell based on a TA (e.g., received from a base station), and then the UE (e.g., through a contention-based and / or contention-free random access procedure) reconnects to the same cell (i.e., the target cell where the failure occurred) using a new TA (e.g., through LTM fast recovery and / or RRC reconstruction), the TA corresponding to the UE's failed access to the target cell is the TA used when the UE failed to access the target cell and / or the TA used by the UE when (attempting) to access the target cell. The TA corresponding to the UE's reconnection to the same cell using a new TA (e.g., through a contention-based and / or contention-free random access procedure) is the TA used when the UE successfully accessed the target cell. For example, if the difference between the TA used when the UE failed to access the target cell and the TA used when the UE successfully accessed the target cell is too large (e.g., greater than and / or equal to a specific threshold) and / or inconsistent, the reason can be considered as TA failure and / or...

[0196] The TA (Transmission Tag) may be inapplicable and / or the TA sent by the base station to the UE may be invalid and / or the TA calculated by the UE may be invalid and / or the TA calculated by the UE may be inapplicable. The target cell where access failed and the target cell where access was successfully established can be the same cell. For example, if the difference between the TA used by the UE when (attempting) to access the target cell and the TA used when the UE successfully accessed the target cell is too large (e.g., greater than and / or equal to a specific threshold) and / or inconsistent, the cause can be considered as TA invalid and / or TA inapplicable and / or the TA sent by the base station to the UE may be invalid and / or the TA calculated by the UE may be invalid ... sent by the base station to the UE may be invalid and / or the TA sent by the UE may be invalid and / or the TA sent by the UE may be invalid and / or the TA sent by the UE may be invalid and / or the TA sent by the UE may be invalid and / or the TA sent by the UE may be invalid and / or the TA sent by the UE may be invalid and / or the TA sent by the UE may be invalid and / or the TA sent by the UE may be invalid and / or the TA sent by the UE may be invalid and / or the

[0197] Or the TA calculated by the UE is not applicable. The target cell for (attempted) access and the target cell for successful access can be the same cell. For example, if the difference between the TA used when the UE fails to access the target cell and the TA used when the UE successfully accesses the target cell is too large (e.g., greater than and / or equal to a certain threshold) and / or inconsistent, the reason can be considered as TA failure.

[0198] The TA (Target Aspect Ratio) may be inapplicable, and / or the TA sent by the base station to the UE may be invalid, and / or the TA calculated by the UE may be invalid, and / or the TA calculated by the UE may be inapplicable. The target cell for failed access and the target cell for successful access can be the same cell. For example, if the difference between the TA used when the UE fails to access the target cell and the TA used when the UE successfully accesses the target cell is too large (e.g., greater than and / or equal to a specific threshold) and / or inconsistent, the cause can be considered as TA invalid and / or TA inapplicable, and / or the TA sent by the base station to the UE may be invalid, and / or the TA calculated by the UE may be invalid, and / or the TA calculated by the UE may be inapplicable. The target cell for failed access and the target cell for successful access can be the same cell. Alternatively, the node can determine the cause based on Layer 1 measurement results and / or Layer 3 measurement results. For example, the node can determine whether the TA provided to the UE and / or the TA measured by the UE are correct and / or invalid based on Layer 1 measurement results and / or Layer 3 measurement results. The excessive difference can refer to a difference greater than and / or equal to a specific threshold. The above can also be the definition and / or concept of TA failure and / or TA inapplicability and / or TA failure sent by the base station to the UE and / or TA inapplicability sent by the base station to the UE and / or TA failure calculated by the UE and / or TA inapplicability calculated by the UE.

[0199] In some implementations, for example, when it is found that the reason for the UE's failure to access the target cell is a TA failure, if the TA used by the UE to access the target cell is received from the base station, the node can perform optimization, for example, optimizing the maintenance of the TA's validity period. For example, when it is found that the reason for the UE's failure to access the target cell is a TA failure, if the TA used by the UE to access the target cell is calculated by the UE, the node may not perform optimization. Alternatively, the node may no longer allow and / or configure the UE to use the TA calculated by the UE to access the target cell. Alternatively, the node may not send this information to other nodes for related optimization (e.g., not sending this information to the corresponding source node and / or last serving node (e.g., source node and / or source node CU and / or source node DU and / or last serving node CU and / or last serving node DU) for related optimization). For example, when it is found that the reason for the UE's failure to access the target cell is the failure of the TA, if the TA used by the UE to access the target cell is obtained through random access (based on contention and / or without contention), the node may not perform optimization. Alternatively, the node may send the information to the corresponding node (e.g., the target node and / or the target node CU and / or the target node DU and / or the source node and / or the source node CU and / or the source node DU and / or the last serving node CU and / or the last serving node DU) for the corresponding node to optimize the calculation of the TA and / or the random access process. Alternatively, the node may not send the information to other nodes for related optimization (e.g., not sending the information to the corresponding source node and / or the last serving node (e.g., the source node and / or the source node CU and / or the source node DU and / or the last serving node CU and / or the last serving node DU) for related optimization).

[0200] In the above information, one or more of the following TAs—the TA used when the UE fails to access the target cell, and / or the TA used when the UE attempts to access the target cell, and / or the TA used when the UE successfully accesses the target cell—can be TAs obtained through contention-based and / or contention-free random access procedures, TAs calculated by the UE, or TAs received by the UE from the base station. If the TA is received by the UE from the base station, it can also be called a pre-synchronized TA, a TA sent by the base station, or a TA in the LTM cell switching command.

[0201] The Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, and / or the TCI status and / or beam information used when accessing the target cell fails, and / or the TCI status and / or beam information used when (attempting) access to the target cell can be the TCI status and / or beam information received by the UE from the base station, or the TCI status and / or beam information determined by the UE and / or the base station (based on measurement results). If the TCI status and / or beam information is received by the UE from the base station, it can also be referred to as the TCI status and / or beam information sent by the base station, the TCI status and / or beam information received by the UE from the base station, or the TCI status and / or beam information in the LTM cell switching command.

[0202] In some implementations of the above information, for example, the target cell mentioned in different pieces of information may be the same cell. For instance, the target cell for (attempted) access, the target cell for failed access, and the target cell for successful access mentioned in the above information may be the same cell. In some implementations, for example, the UE targeted by the above information may be the same UE; that is, the various pieces of information may be information associated with the same UE.

[0203] Example 3

[0204] This disclosure proposes a method to support mobility self-optimization, which may include: a seventh node sending a fourth message to an eighth node containing information that triggers the recording and / or reporting of LTM cell transition-related information. When the eighth node detects that the information triggers the recording and / or reporting of LTM cell transition-related information is met, it records and / or reports the LTM cell transition-related information.

[0205] In some implementations, the fourth message may be included in one or more of the following: a switch request confirmation message for Xn; a reconfiguration message for RRC; or another and / or a newly defined MAC CE and / or RRC container and / or RRC and / or Xn and / or X2 and / or F1 and / or E1 and / or NG message.

[0206] In some implementations, the fourth message may include one or more of the following fields:

[0207] • UE Identifier: Indicates the UE corresponding to the information recorded and / or reported that triggered the LTM cell transition.

[0208] • Information related to triggering LTM cell transition recording and / or reporting: Refer to the information in the third message.

[0209] • The threshold corresponding to the difference between the TA used when the UE fails to access the target cell and the TA used when the UE successfully accesses the target cell: When the difference between the TA used when the UE fails to access the target cell and the TA used when the UE successfully accesses the target cell is greater than and / or equal to and / or less than the threshold corresponding to the difference between the TA used when the UE fails to access the target cell and the TA used when the UE successfully accesses the target cell, LTM cell transition information is recorded and / or reported. The LTM cell transition information can be referred to in the third message. In some implementations, when the difference between the TA used when the UE fails to access the target cell and the TA used when the UE successfully accesses the target cell is greater than and / or equal to a threshold corresponding to the difference between the TA used when the UE fails to access the target cell and the TA used when the UE successfully accesses the target cell, one or more of the following information is recorded and / or reported in the LTM cell transition information: the TA used when the UE successfully accessed the target cell, the TA used when the UE failed to access the target cell, the difference between the TA used when the UE failed to access the target cell and the TA used when the UE successfully accessed the target cell, the TA used by the UE (attempting) to access the target cell, the difference between the TA used by the UE (attempting) to access the target cell and the TA used when the UE successfully accessed the target cell, Layer 1 measurement results, Layer 3 measurement results, etc. In some implementations, for example, this information may be specified by the source node and / or the target node.

[0210] The threshold corresponding to the difference between the TA used by the UE (attempting) to access the target cell and the TA used when the UE successfully accessed the target cell: When the difference between the TA used by the UE (attempting) to access the target cell and the TA used when the UE successfully accessed the target cell is greater than and / or equal to and / or less than the threshold corresponding to the difference between the TA used by the UE (attempting) to access the target cell and the TA used when the UE successfully accessed the target cell, LTM cell conversion related information is recorded and / or reported. The LTM conversion related information can refer to the third message. In some embodiments, when the difference between the TA used by the UE (attempting) to access the target cell and the TA used when the UE successfully accessed the target cell is greater than and / or equal to and / or less than the threshold corresponding to the difference between the TA used by the UE (attempting) to access the target cell and the TA used when the UE successfully accessed the target cell, LTM cell conversion related information is recorded and / or reported.

[0211] When the difference between the TA used when successfully accessing the target cell and the TA used when the UE (attempted) accesses the target cell is greater than and / or equal to the threshold corresponding to the difference between the TA used when the UE (attempted) accesses the target cell and the TA used when the UE successfully accesses the target cell, one or more of the following information is recorded and / or reported in the LTM cell transition information: the TA used when the UE successfully accesses the target cell, the TA used when the UE fails to access the target cell, the difference between the TA used when the UE fails to access the target cell and the TA used when the UE successfully accesses the target cell, the TA used when the UE (attempted) accesses the target cell, the difference between the TA used when the UE (attempted) accesses the target cell and the TA used when the UE successfully accesses the target cell, Layer 1 measurement results, Layer 3 measurement results, etc. In some implementations, for example, this information may be specified by the source node and / or the target node.

[0212] • The threshold corresponding to the difference between the TCI status and / or beam information used when access to the target cell fails and the TCI status and / or beam information used when access to the target cell is successful:

[0213] When the difference between the TCI state and / or beam information used when accessing the target cell fails and the TCI state and / or beam information used when successfully accessing the target cell is greater than and / or equal to and / or less than the threshold corresponding to the difference between the TCI state and / or beam information used when accessing the target cell fails and the TCI state and / or beam information used when successfully accessing the target cell, LTM cell transition information is recorded and / or reported. The LTM transition information can be referred to in the third message. In some implementations, when the threshold corresponding to the difference between the TCI state and / or beam information used when accessing the target cell fails and the TCI state and / or beam information used when successfully accessing the target cell is greater than and / or equal to the threshold corresponding to the difference between the TCI state and / or beam information used when accessing the target cell fails and the TCI state and / or beam information used when successfully accessing the target cell, one or more of the following information are recorded and / or reported in the LTM cell transition related information: the TCI state and / or beam information used when successfully accessing the target cell, the TCI state and / or beam information used when accessing the target cell fails, the difference between the TCI state and / or beam information used when accessing the target cell fails and the TCI state and / or beam information used when successfully accessing the target cell, the TCI state and / or beam information used when (attempted) accessing the target cell, the difference between the TCI state and / or beam information used when (attempted) accessing the target cell and the TCI state and / or beam information used when successfully accessing the target cell, Layer 1 measurement results, Layer 3 measurement results, etc. In some implementations, for example, this information may be specified by the source node and / or the target node.

[0214] • The threshold corresponding to the difference between the TCI state and / or beam information used when attempting to access the target cell and the TCI state and / or beam information used when successfully accessing the target cell:

[0215] When the threshold corresponding to the difference between the TCI state and / or beam information used in the (attempted) access to the target cell and the TCI state and / or beam information used when successfully accessing the target cell is greater than and / or equal to and / or less than the threshold corresponding to the difference between the TCI state and / or beam information used in the (attempted) access to the target cell and the TCI state and / or beam information used when successfully accessing the target cell, LTM cell transition information is recorded and / or reported. The LTM transition information can be referred to in the third message. In some embodiments, when the threshold corresponding to the difference between the TCI state and / or beam information used in the (attempted) access to the target cell and the TCI state and / or beam information used when successfully accessing the target cell is greater than and / or equal to and / or less than ... the threshold corresponding to the difference between the TCI state and / or beam information used in the (attempted) access to the target cell and the TCI state and / or beam information used when successfully accessing the target cell is greater than and / or equal to the threshold corresponding to the difference between the TCI state and / or beam information used in the (attempted) access to the target cell and the TCI state and / or beam information used when successfully accessing the target cell is greater than and / or equal to the threshold corresponding to the difference between the TCI state and / or beam information used in the (attempted) access to the target cell and the TCI state and / or beam information used in the (attempted) access to the target cell is greater than and / or equal to the threshold corresponding to the difference between the TCI state and / or beam information used in the (attempted) access

[0216] When the value is equal to or equal to the threshold corresponding to the difference between the TCI state and / or beam information used when attempting to access the target cell and the TCI state and / or beam information used when successfully accessing the target cell, one or more of the following information is recorded and / or reported in the LTM cell transition information: the TCI state and / or beam information used when successfully accessing the target cell, the TCI state and / or beam information used when accessing the target cell failed, the difference between the TCI state and / or beam information used when accessing the target cell failed and the TCI state and / or beam information used when successfully accessing the target cell, the TCI state and / or beam information used when attempting to access the target cell, the difference between the TCI state and / or beam information used when attempting to access the target cell and the TCI state and / or beam information used when successfully accessing the target cell, Layer 1 measurement results, Layer 3 measurement results, etc. In some implementations, for example, this information may be specified by the source node and / or the target node.

[0217] • Events that trigger the recording and / or reporting of LTM cell handover related information: When this event is met,

[0218] Record and / or report relevant information. The events may include one or more of the following:

[0219] The system fails to detect UE access to the target cell using the TCI status and / or beam information received from the source node during the LTM process (e.g., a radio link failure occurred, such as a handover failure), but subsequently detects the same UE accessing the target cell during the aforementioned LTM process using different TCI status and / or beam information.

[0220] o After a UE accesses the target cell, a radio link failure occurs. Subsequently, different TCI states and / or beam information are used to detect that the same UE accessed the target cell in the above LTM process.

[0221] o Beam Failure Recovery occurs after the UE accesses the target cell. In some implementations, this may be because the beam corresponding to the beam used by the UE to access the target cell is different from and / or the beam corresponding to the beam used by the UE after beam failure recovery is large.

[0222] The target cell cannot be accessed using the TA received from the source node during the LTM process.

[0223] (For example, a radio link failure occurs. For example, a radio link failure could be a handover failure), and then the UE accesses and / or connects to the target cell in the LTM process described above using a different TA.

[0224] If a UE experiences a radio link failure after accessing the target cell, and then the UE re-accesses and / or reconnects to the target cell during the LTM process described above using a different TA, for example, through a fast recovery process.

[0225] Exemplary embodiments of this disclosure are further described below with reference to the accompanying drawings.

[0226] The text and accompanying drawings are provided by way of example only to aid in understanding this disclosure. They should not be construed as limiting the scope of this disclosure in any way. Although certain embodiments and examples have been provided, it will be apparent to those skilled in the art, based on the content disclosed herein, that changes may be made to the illustrated embodiments and examples without departing from the scope of this disclosure.

[0227] Figure 3A A schematic diagram of one aspect of a method for supporting mobility self-optimization according to embodiments of the present disclosure is shown. Specifically, Figure 3AThis diagram illustrates the process of exchanging LTM cell transition information between two nodes, allowing the second node to acquire this information. The second node can then perform self-optimization based on the received LTM cell transition information. For example, the second node can perform mobility robustness optimization based on the received LTM cell transition information. This information can be used by the second node to analyze the causes of LTM-related radio link failures and / or potential failures and / or near-failures, and to perform related self-optimization. LTM cell transition information can also be used by the second node to analyze whether the problem originates from itself or other nodes when analyzing radio link causes, and to perform related self-optimization. The second node can also forward LTM cell transition information to other nodes for them to analyze failure causes and perform related self-optimization. This scheme can optimize mobility robustness to ensure mobility robustness and reduce and / or avoid failures.

[0228] In some implementations, for example, the first node may be a UE, and the second node may be a gNB, gNB-CU, gNB-DU, gNB CU-CP, gNB CU-UP, en-gNB, eNB, or ng-eNB. In other implementations, for example, the first node may be a gNB, gNB-CU, gNB CU-CP, en-gNB, eNB, or ng-eNB, and the second node may be a gNB, gNB-CU, gNB-DU, gNB CU-CP, gNB CU-UP, en-gNB, eNB, or ng-eNB. In still other implementations, for example, the first node may be an AMF, SMF, or MME, and the second node may be a gNB, gNB-CU, gNB CU-CP, en-gNB, eNB, or ng-eNB. In yet another implementation, for example, the first node may be a gNB, gNB-CU, gNB CU-CP, en-gNB, eNB, or ng-eNB, and the second node may be an AMF, SMF, or MME. For example, the first node is the source node, and the second node is the destination node. Alternatively, the first node is the destination node, and the second node is the source node. Or, the first node is a node, and the second node is the final service node. Another example is that the first node is a gNB DU, and the second node is a gNB CU. Finally, the first node is a gNB CU, and the second node is a gNB DU. Here, gNB can be a source node, a destination node, or a final service node.

[0229] Step 301A: Optionally, the first node sends information related to the availability of LTM cell transition information to the second node. The information related to the availability of LTM cell transition information may be the aforementioned first message.

[0230] Step 302A: Optionally, the second node sends an LTM cell transition related information request to the first node based on its own situation and / or based on a first message received from the first node containing information related to the availability of LTM cell transition related information, in order to request the first node to report LTM cell transition related information. The LTM cell transition related information request may be the aforementioned second message.

[0231] Step 303A: The first node sends a third message containing LTM cell transition information to the second node, allowing the second node to obtain this information. In step 304A, the second node can perform cause analysis and / or self-optimization based on the received LTM cell transition information. For example, the second node can perform mobility robustness optimization based on the received LTM cell transition information. For instance, the LTM cell transition information can be used by the second node to analyze the causes of LTM-related radio link failures and / or potential failures and / or near-failures, and to perform related self-optimization. The LTM cell transition information can also be used by the second node to analyze whether the problem originates from itself or other nodes when analyzing radio link causes, and to perform related self-optimization. The LTM cell transition information can also be forwarded by the second node to other nodes for them to analyze failure causes and perform related self-optimization. This scheme can optimize mobility robustness to ensure mobility robustness and reduce and / or avoid failures.

[0232] Figure 3B A schematic diagram of one aspect of a method for supporting mobility self-optimization according to embodiments of the present disclosure is shown. Specifically, Figure 3B The process of exchanging LTM cell transition information between nodes is illustrated, allowing a fourth node and / or a third node to obtain this information. The fourth and / or third nodes can perform self-optimization based on the received LTM cell transition information. For example, they can perform mobility robustness optimization. Alternatively, the LTM cell transition information can be used by a fifth node to analyze whether a problem originates from itself or another node when analyzing radio link causes, and to perform related self-optimization. The fifth node can also forward the LTM cell transition information to other nodes for them to analyze failure causes and perform related self-optimization. Furthermore, the LTM cell transition information can be used by the fourth and / or third nodes to perform related self-optimization based on the causes of LTM-related radio link failures and / or potential failures and / or near-failures. For example, self-optimization can be mobility robustness optimization. This scheme can optimize mobility robustness to ensure mobility robustness and reduce and / or avoid failures.

[0233] In some implementations, for example, the third node may be the source node DU of the switch, the fourth node may be the source node CU of the switch, the fifth node may be the target node and / or the target node CU and / or the last serving node and / or the last serving node CU of the switch, the eighth node may be the target node and / or the target node DU and / or the last serving node and / or the last serving node DU of the switch, and the sixth node may be other nodes.

[0234] Step 300B: Optionally, the third node sends LTM cell transition-related information and / or information triggering the recording and / or reporting of LTM cell transition-related information to the fourth node. The LTM cell transition-related information may be the aforementioned third message. The information triggering the recording and / or reporting of LTM cell transition-related information may be the aforementioned fourth message. The LTM cell transition-related information and / or information triggering the recording and / or reporting of LTM cell transition-related information may be sent via a UE context release complete message and / or a UE context release request message.

[0235] In some implementations, the LTM cell transition information sent by the third node to the fourth node may include one or more of the following: information related to the acquisition method of the TA used by the UE to access the target cell, a first TA for the UE (attempting) to access the target cell, a first Transport Configuration Indicator (TCI) state for the UE (attempting) to access the target cell, and first beam information for the UE (attempting) to access the target cell. Furthermore, the LTM cell transition information sent by the third node to the fourth node may also include any other one or more of the information in the third message as described above.

[0236] Step 301B: The fourth node sends LTM cell transition-related information and / or information that triggers the recording and / or reporting of LTM cell transition-related information to the fifth node. The LTM cell transition-related information may be the aforementioned third message. The information that triggers the recording and / or reporting of LTM cell transition-related information may be the aforementioned fourth message. The LTM cell transition-related information can be sent via an SN STATUS TRANSFER message.

[0237] In some implementations, the LTM cell transition information sent by the fourth node to the fifth node may also be referred to as the first information. In some implementations, the first information may include one or more of the following: LTM cell transition information received by the fourth node from the third node; information related to the UE's simultaneous configuration of conditional handover and Layer 1 / Layer 2 triggered mobility LTM handover; the UE's conditional handover configuration; the UE's LTM handover configuration; and information related to the UE's handover triggering status. Furthermore, the first information may also include any other one or more of the information in the third message described above.

[0238] Step 301B.a: Optionally, the fifth node sends LTM cell transition-related information and / or information triggering the recording and / or reporting of LTM cell transition-related information to the eighth node. The LTM cell transition-related information may be the aforementioned third message. The information triggering the recording and / or reporting of LTM cell transition-related information may be the aforementioned fourth message. The LTM cell transition-related information and / or information triggering the recording and / or reporting of LTM cell transition-related information may be sent via an Access and Mobility Indication (ACCESS AND MOBILITY INDICATION) message.

[0239] In some implementations, the LTM cell transition information sent by the fifth node to the eighth node may be LTM cell transition information received by the fifth node and / or determined by the fifth node itself.

[0240] The fifth node can also obtain the UE's radio link failure report. The UE's radio link failure report can be collected and / or obtained through method A and / or method B as described below. This step is optional.

[0241] Method A:

[0242] Step 302B: The UE sends information related to the availability of the radio link failure report to the fifth node.

[0243] Step 303B: The fifth node sends a radio link failure report request to the UE.

[0244] Step 304B: The UE sends a radio link failure report to the fifth node.

[0245] Method B:

[0246] Step 304B.b: The sixth node sends the UE's radio link failure report to the fifth node.

[0247] Step 305B: Optionally, the eighth node sends LTM cell transition information to the fifth node. The LTM cell transition information can be sent via a DU-CU Access and Mobility Indication (DU-CU ACCESS AND MOBILITY INDICATION) message.

[0248] In some implementations, the LTM cell transition information sent by the eighth node to the fifth node may also be referred to as the second information. In some implementations, the second information may include one or more of the following: the second TA used when the UE successfully accesses the target cell; the third TA used when the UE fails to access the target cell; the second TCI state used when the UE successfully accesses the target cell; the third TCI state used when the UE fails to access the target cell; the second beam information used when the UE successfully accesses the target cell; and the third beam information used when the UE fails to access the target cell. Furthermore, the second information may also include any other one or more of the third messages described above.

[0249] Step 306B: The fifth node performs cause analysis based on the radio link failure report and / or LTM cell transition information. The LTM cell transition information may be stored by the fifth node, and / or received by the fifth node from the fourth node, and / or received by the fifth node from the eighth node.

[0250] Step 307B: The fifth node sends LTM cell transition information to the fourth node. This LTM cell transition information may be the aforementioned third message. It can also be sent via a handover report message. If the analysis indicates that the source node needs optimization, the fifth node sends the LTM cell transition information to the fourth node; for example, the analyzed cause might be premature handover, premature cell transition, handover to the wrong cell, or the cause mentioned in the third message. In some implementations, for example, the fourth node may perform cause analysis and / or self-optimization based on the LTM cell transition information.

[0251] In some implementations, the LTM cell handover information sent by the fifth node to the fourth node may also be referred to as third information. In some implementations, the third information may include one or more of the following: first information received by the fifth node, second information received by the fifth node, the reason for the UE's handover failure, and / or the potential reason for handover failure. Furthermore, the third information may also include any other one or more of the third messages described above.

[0252] Step 308B: Optionally, the fourth node sends LTM cell transition information to the third node. The LTM cell transition information may be the aforementioned third message. The LTM cell transition information can be sent via an Access and Mobility Indication (ACCESS AND MOBILITY INDICATION) message. If the analysis result indicates that the source node DU needs optimization, the fourth node sends the LTM cell transition information to the third node; for example, the analyzed cause may be premature handover, premature cell transition, handover to the wrong cell, or the cause mentioned in the third message. In some implementations, for example, the third node may perform cause analysis and / or self-optimization based on the LTM cell transition information.

[0253] Step 305B may occur before and / or simultaneously with step 302B, step 303B, or step 304B.

[0254] Figure 3C A schematic diagram of one aspect of a method for supporting mobility self-optimization according to embodiments of the present disclosure is shown. Specifically, Figure 3C The process of exchanging LTM cell transition information between nodes is illustrated, allowing a fourth node and / or a third node to obtain this information. The fourth and / or third nodes can perform self-optimization based on the received LTM cell transition information. For example, they can perform mobility robustness optimization. Alternatively, the LTM cell transition information can be used by a fifth node to analyze whether a problem originates from itself or another node when analyzing radio link causes, and to perform related self-optimization. The fifth node can also forward the LTM cell transition information to other nodes for them to analyze failure causes and perform related self-optimization. Furthermore, the LTM cell transition information can be used by the fourth and / or third nodes to perform related self-optimization based on the causes of LTM-related radio link failures and / or potential failures and / or near-failures. For example, self-optimization can be mobility robustness optimization. This scheme can optimize mobility robustness to ensure mobility robustness and reduce and / or avoid failures.

[0255] In some implementations, for example, the third node may be the source node DU of the switch, the fourth node may be the source node CU of the switch, the fifth node may be the target node and / or the target node CU and / or the last serving node and / or the last serving node CU of the switch, and the sixth node may be other nodes.

[0256] Step 301C: Optionally, the third node and / or the fourth node send LTM cell transition-related information and / or information triggering LTM cell transition-related information recording and / or reporting to the UE. The LTM cell transition-related information may be the aforementioned third message. The information triggering LTM cell transition-related information recording and / or reporting may be the aforementioned fourth message. The LTM cell transition information can be sent via MAC CE and / or Layer 1 messages. The LTM cell transition-related information can be sent via RRC reconfiguration messages. The information triggering LTM cell transition-related information recording and / or reporting can be sent via MAC CE and / or Layer 1 messages. The information triggering LTM cell transition-related information recording and / or reporting can be sent via RRC reconfiguration messages.

[0257] The fifth node can also obtain LTM cell transition information of the UE. This LTM cell transition information can be collected and / or obtained through the methods described below, A and / or B.

[0258] Method A:

[0259] Step 302C: The UE sends information related to the availability of LTM cell transition information to the fifth node. This information may be the aforementioned first message.

[0260] Step 303C: The fifth node sends an LTM cell transition information request to the UE. The LTM cell transition information request may be the aforementioned second message.

[0261] Step 304C: The UE sends LTM cell transition information to the fifth node. The LTM cell transition information may be the aforementioned third message.

[0262] Method B:

[0263] Step 304C.b: The sixth node sends LTM cell transition information to the fifth node. The LTM cell transition information may be the aforementioned third message. The LTM cell transition information may be sent via a HANDOVERREPORT message, an ACCESS AND MOBILITY INDICATION message, or a FAILURE INDICATION message.

[0264] One or more of the following steps may also occur before step 304C.b in method B: step 302D, step 303D, and step 304D.

[0265] Step 305C: The fifth node performs cause analysis based on LTM cell switching information.

[0266] Step 306C: The fifth node sends LTM cell transition information to the fourth node. This LTM cell transition information may be the aforementioned third message. It can also be sent via a handover report message. If the analysis indicates that the source node needs optimization, the fifth node sends the LTM cell transition information to the fourth node. For example, the analyzed cause might be premature handover, premature cell transition, handover to the wrong cell, or the cause mentioned in the third message. In some implementations, for example, the fourth node can perform cause analysis and / or self-optimization based on the LTM cell transition information.

[0267] Step 307C: Optionally, the fourth node sends LTM cell transition information to the third node. The LTM cell transition information may be the aforementioned third message. The LTM cell transition information can be sent via an Access and Mobility Indication (ACCESS AND MOBILITY INDICATION) message. If the analysis result indicates that the source node DU needs optimization, the fourth node sends the LTM cell transition information to the third node. For example, the analyzed cause may be premature handover, premature cell transition, handover to the wrong cell, or the cause mentioned in the third message. In some implementations, for example, the third node may perform cause analysis and / or self-optimization based on the LTM cell transition information.

[0268] Figure 3D A schematic diagram of one aspect of a method for supporting mobility self-optimization according to embodiments of the present disclosure is shown. Specifically, Figure 3D The process of exchanging LTM cell transition information between nodes is illustrated, allowing a fourth node and / or a third node to obtain this information. The fourth and / or third nodes can perform self-optimization based on the received LTM cell transition information. For example, they can perform mobility robustness optimization. Alternatively, the LTM cell transition information can be used by a fifth node to analyze whether a problem originates from itself or another node when analyzing radio link causes, and to perform related self-optimization. The fifth node can also forward the LTM cell transition information to other nodes for them to analyze failure causes and perform related self-optimization. Furthermore, the LTM cell transition information can be used by the fourth and / or third nodes to perform related self-optimization based on the causes of LTM-related radio link failures and / or potential failures and / or near-failures. For example, self-optimization can be mobility robustness optimization. This scheme can optimize mobility robustness to ensure mobility robustness and reduce and / or avoid failures.

[0269] In some implementations, for example, the third node may be the last serving node and / or the last serving node DU and / or the target node and / or the target node DU, the fourth node may be the last serving node and / or the last serving node CU and / or the target node and / or the target node CU, and the sixth node may be any other node. In other implementations, for example, the third node may be the last serving node and / or the last serving node DU and / or the target node and / or the target node DU, the fourth node may be the last serving node and / or the last serving node CU and / or the target node and / or the target node CU, and the sixth node may also be the last serving node and / or the last serving node CU and / or the target node and / or the target node CU. In this case, the fourth node and the sixth node may be the same node. The interaction between the fourth node and the sixth node may be omitted. In yet another implementation, for example, the third node may be the source node and / or the source node DU, the fourth node may be the source node and / or the source node CU, and the sixth node may be the target node and / or the target node CU and / or any other node.

[0270] Step 301D: Optionally, the third node and / or the fourth node send LTM cell transition-related information and / or information triggering LTM cell transition-related information recording and / or reporting to the UE. The LTM cell transition-related information may be the aforementioned third message. The information triggering LTM cell transition-related information recording and / or reporting may be the aforementioned fourth message. The LTM cell transition information can be sent via MAC CE and / or Layer 1 messages. The LTM cell transition-related information can be sent via RRC reconfiguration messages. The information triggering LTM cell transition-related information recording and / or reporting can be sent via MAC CE and / or Layer 1 messages. The information triggering LTM cell transition-related information recording and / or reporting can be sent via RRC reconfiguration messages.

[0271] Step 302D: The UE sends information related to the availability of LTM cell transition information to the sixth node. This information may be the aforementioned first message.

[0272] Step 303D: The sixth node sends an LTM cell switching related information request to the UE. The LTM cell switching related information request may be the aforementioned second message.

[0273] Step 304D: The UE sends LTM cell transition information to the sixth node. The LTM cell transition information may be the aforementioned third message.

[0274] Step 305D: The sixth node sends LTM cell transition information to the fourth node. The LTM cell transition information may be the aforementioned third message. This information can be sent via a Handover Report message, an Access and Mobility Indication message, or a Failure Indication message. In some implementations, for example, the fourth node may perform cause analysis and / or self-optimization based on the LTM cell transition information.

[0275] Step 306D: Optionally, the fourth node sends LTM cell transition information to the third node. The LTM cell transition information may be the aforementioned third message. The LTM cell transition information can be sent via an Access and Mobility Indication (ACCESS AND MOBILITY INDICATION) message. If the analysis result indicates that the last serving node (DU) needs optimization, for example, if the analyzed cause is late handover, the fourth node sends the LTM cell transition information to the third node. In some implementations, for example, the third node may perform cause analysis and / or self-optimization based on the LTM cell transition information.

[0276] In the above embodiments, the sixth node and the fourth node and / or the third node can be the same node.

[0277] Figure 3E A schematic diagram of one aspect of a method for supporting mobility self-optimization according to embodiments of the present disclosure is shown. Specifically, Figure 3E This illustrates the process by which inter-node interactions trigger the recording and / or reporting of LTM cell transition-related information. When a node detects information that satisfies the trigger for recording and / or reporting LTM cell transition-related information, it records and / or reports the relevant information.

[0278] In some implementations, for example, the seventh node may be the last serving node and / or the last serving node DU and / or the target node and / or the target node DU, and the eighth node may be the source node and / or the source node CU. In other implementations, for example, the seventh node may be the source node and / or the source node CU, and the eighth node may be the last serving node and / or the last serving node DU and / or the target node and / or the target node DU. In yet another implementation, for example, the seventh node may be a gNB and / or the last serving node and / or the last serving node DU and / or the target node and / or the target node DU, and the eighth node may be a UE. In still other implementations, for example, the seventh node may be a gNB and / or the source node and / or the source node CU, and the eighth node may be a UE.

[0279] Step 301E: The seventh node sends information related to triggering LTM cell transition records and / or reports to the eighth node. The information related to triggering LTM cell transition records and / or reports may be the aforementioned fourth message.

[0280] Step 302E: When the eighth node detects information that triggers the recording and / or reporting of LTM cell transition-related information, it records and / or reports the LTM cell transition-related information. Alternatively, the eighth node forwards the information triggering the recording and / or reporting of LTM cell transition-related information to other nodes for other nodes to record and / or report LTM cell transition-related information.

[0281] Figure 3F A schematic diagram of one aspect of a method for supporting mobility self-optimization according to embodiments of the present disclosure is shown. Specifically, Figure 3F This illustrates the process by which inter-node interactions trigger the recording and / or reporting of LTM cell transition-related information. When a node detects information that satisfies the trigger for recording and / or reporting LTM cell transition-related information, it records and / or reports the relevant information.

[0282] In some implementations, for example, the seventh node may be the last serving node and / or the last serving node DU and / or the target node and / or the target node DU, and the eighth node may be the source node and / or the source node CU. In other implementations, for example, the seventh node may be the source node and / or the source node CU, and the eighth node may be the last serving node and / or the last serving node DU and / or the target node and / or the target node DU.

[0283] Step 301F: The seventh node sends information related to triggering LTM cell transition records and / or reports to the eighth node. The information related to triggering LTM cell transition records and / or reports may be the aforementioned fourth message.

[0284] Step 302F: The eighth node sends LTM cell transition related information records and / or reporting information to the UE. The LTM cell transition related information records and / or reporting information may be the aforementioned fourth message. In some implementations, for example, the eighth node may add to and / or supplement and / or modify the LTM cell transition related information records and / or reporting information received from the seventh node before sending the final LTM cell transition related information records and / or reporting information to the UE.

[0285] Step 303F: When the UE detects information that triggers the recording and / or reporting of LTM cell transition related information, it records and / or reports the LTM cell transition related information. Alternatively, the eighth node forwards the information that triggers the recording and / or reporting of LTM cell transition related information to other nodes for other nodes to record and / or report LTM cell transition related information.

[0286] Figure 3G A schematic diagram of one aspect of a method for supporting mobility self-optimization according to embodiments of the present disclosure is shown. Specifically, Figure 3G The process of exchanging LTM cell transition information between nodes is illustrated, allowing a fourth node and / or a third node to obtain this information. The fourth and / or third nodes can perform self-optimization based on the received LTM cell transition information. For example, they can perform mobility robustness optimization. Alternatively, the LTM cell transition information can be used by a fifth node to analyze whether a problem originates from itself or another node when analyzing radio link causes, and to perform related self-optimization. The fifth node can also forward the LTM cell transition information to other nodes for them to analyze failure causes and perform related self-optimization. Furthermore, the LTM cell transition information can be used by the fourth and / or third nodes to perform related self-optimization based on the causes of LTM-related radio link failures and / or potential failures and / or near-failures. For example, self-optimization can be mobility robustness optimization. This scheme can optimize mobility robustness to ensure mobility robustness and reduce and / or avoid failures.

[0287] In some implementations, for example, the third node can be the source node DU during handover, the fourth node can be the source node CU during handover, the fifth node can be the target node and / or the target node CU and / or the last serving node and / or the last serving node CU during handover, and the eighth node can be the target node and / or the target node DU and / or the last serving node and / or the last serving node DU during handover. If handover fails, the last serving node is the source node. If a radio link failure occurs after a successful handover, the last serving node is the target node.

[0288] Step 301G: The eighth node sends LTM cell transition information to the fifth node. The LTM cell transition information may be the aforementioned third message.

[0289] Step 302G: The fifth node sends LTM cell transition information to the fourth node. The LTM transition information may be the aforementioned third message.

[0290] Step 303G: The fourth node sends LTM cell switching information to the third node. The LTM switching information may be the aforementioned third message.

[0291] In cases where beam information errors and / or TCI status information errors occur, the various embodiments of this disclosure may also include the following implementation methods, hereinafter referred to as... Figure 3G Described as an example:

[0292] Implementation method A:

[0293] Step 301G: The eighth node analyzes the cause (which can be a failure cause, a potential failure cause, or a near-failure cause, or a successful handover with potential problems). If the analyzed cause is an incorrect beam information and / or an incorrect TCI status information, the eighth node sends LTM cell transition information to the fifth node. The LTM cell transition information can be the aforementioned third message. In some implementations, for example, the LTM cell transition information can include all and / or part of the third message. For example, it can include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when (attempting) accessing the target cell, the difference between the TCI status and / or beam information used when (attempting) accessing the target cell and the TCI status and / or beam information used when successfully accessing the target cell, the cause, etc.

[0294] Step 302G: The fifth node sends LTM cell transition information to the fourth node. The LTM transition information may be the aforementioned third message. In some implementations, for example, the LTM cell transition information may include all and / or part of the third message. For example, it may include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when attempting to access the target cell, the difference between the TCI status and / or beam information used when attempting to access the target cell and the TCI status and / or beam information used when successfully accessing the target cell, and the reason, etc.

[0295] Step 303G: The fourth node sends LTM cell transition information to the third node. The LTM transition information may be the aforementioned third message. In some implementations, for example, the LTM cell transition information may include all and / or part of the third message. For example, it may include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when attempting to access the target cell, the difference between the TCI status and / or beam information used when attempting to access the target cell and the TCI status and / or beam information used when successfully accessing the target cell, and the reason, etc.

[0296] The third node performs self-optimization based on the received LTM conversion-related information. This self-optimization can be mobility robustness optimization. For example, it can optimize beam selection and / or TCI status information settings.

[0297] Implementation Method B:

[0298] Step 301G: The eighth node sends LTM cell transition information to the fifth node. The LTM cell transition information may be the aforementioned third message. In some implementations, for example, the LTM cell transition information may include all and / or part of the third message. For example, it may include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when (attempting) accessing the target cell, and the difference between the TCI status and / or beam information used when (attempting) accessing the target cell and the TCI status and / or beam information used when successfully accessing the target cell, etc.

[0299] In some implementations, for example, the eighth node may send LTM cell switching information to the fifth node when it detects the following:

[0300] - The UE access to the target cell cannot be detected using the TCI status and / or beam information received from the source node during the LTM process (e.g., a radio link failure occurred. For example, the radio link failure could be a handover failure), but the same UE access to the target cell during the aforementioned LTM process is subsequently detected using different TCI status and / or beam information.

[0301] - After a UE accesses the target cell, a radio link failure occurs. Subsequently, different TCI states and / or beam information are used to detect that the same UE accessed the target cell in the above LTM process.

[0302] - Beam failure recovery occurs after the UE accesses the target cell. In some implementations, this may be because the beam corresponding to the beam used by the UE to access the target cell is different from and / or the beam corresponding to the beam used by the UE after beam failure recovery is large.

[0303] Step 302G: The fifth node analyzes the cause (this could be a failure cause, a potential failure cause, or a near-failure cause, or a successful handover with potential problems). In some implementations, for example, the fifth node can perform the analysis based on information received from the eighth node and / or its own stored information. If the analyzed cause is a beam information error and / or a TCI status information error, the fifth node sends LTM cell transition information to the fourth node. The LTM cell transition information can be the aforementioned third message. In some implementations, for example, the LTM cell transition information can include all and / or part of the third message. For example, it may include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when (attempting) accessing the target cell, the difference between the TCI status and / or beam information used when (attempting) accessing the target cell and the TCI status and / or beam information used when successfully accessing the target cell, and the reason, etc.

[0304] In some implementations, for example, the fifth node may send LTM cell switching information to the fourth node when it detects the following situation, which can be referred to the situation exemplarily described in step 301G.

[0305] Step 303G: The fourth node sends LTM cell transition information to the third node. The LTM transition information may be the aforementioned third message. In one implementation, for example, the LTM cell transition information may include all and / or part of the third message. For example, it may include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when attempting to access the target cell, the difference between the TCI status and / or beam information used when attempting to access the target cell and the TCI status and / or beam information used when successfully accessing the target cell, and the reason, etc.

[0306] The third node performs self-optimization based on the received LTM conversion-related information. This self-optimization can be mobility robustness optimization. For example, it can optimize beam selection and / or TCI status information settings.

[0307] Implementation method C:

[0308] Step 301G: The eighth node sends LTM cell transition information to the fifth node. The LTM cell transition information may be the aforementioned third message. In some embodiments, for example, the LTM cell transition information may include all and / or part of the third message. For example, it may include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when (attempting) accessing the target cell, and the difference between the TCI status and / or beam information used when (attempting) accessing the target cell and the TCI status and / or beam information used when successfully accessing the target cell, etc.

[0309] In some implementations, for example, the eighth node may send LTM cell switching information to the fifth node when it detects the following:

[0310] - The UE access to the target cell cannot be detected using the TCI status and / or beam information received from the source node during the LTM process (e.g., a radio link failure occurred. For example, the radio link failure could be a handover failure), but the same UE access to the target cell during the aforementioned LTM process is subsequently detected using different TCI status and / or beam information.

[0311] - After a UE accesses the target cell, a radio link failure occurs. Subsequently, different TCI states and / or beam information are used to detect that the same UE accessed the target cell in the above LTM process.

[0312] - Beam failure recovery occurs after the UE accesses the target cell. In some implementations, this may be because the beam corresponding to the beam used by the UE to access the target cell is different from and / or the beam corresponding to the beam used by the UE after beam failure recovery is large.

[0313] Step 302G: The fifth node sends LTM cell transition information to the fourth node. The LTM transition information may be the aforementioned third message. In some implementations, for example, the LTM cell transition information may include all and / or part of the third message. For example, it may include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when attempting to access the target cell, and the difference between the TCI status and / or beam information used when attempting to access the target cell and the TCI status and / or beam information used when successfully accessing the target cell, etc.

[0314] In some implementations, for example, the fifth node may send LTM cell switching information to the fourth node when it detects the following situation, which can be referred to the situation exemplarily described in step 301G.

[0315] Step 303G: The fourth node analyzes the cause (this could be a failure cause, a potential failure cause, or a near-failure cause, or a successful handover with potential problems). In some implementations, for example, the fourth node can perform the analysis based on information received from the fifth node and / or its own stored information. If the analyzed cause is a beam information error and / or a TCI status information error, the fourth node sends LTM cell transition information to the third node. The LTM cell transition information can be the aforementioned third message. In some implementations, for example, the LTM cell transition information can include all and / or part of the third message. For example, it may include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when (attempting) accessing the target cell, the difference between the TCI status and / or beam information used when (attempting) accessing the target cell and the TCI status and / or beam information used when successfully accessing the target cell, and the reason, etc.

[0316] The third node performs self-optimization based on the received LTM conversion-related information. This self-optimization can be mobility robustness optimization. For example, it can optimize beam selection and / or TCI status information settings.

[0317] Implementation method D:

[0318] Step 301G: The eighth node sends LTM cell transition information to the fifth node. The LTM cell transition information may be the aforementioned third message. In some implementations, for example, the LTM cell transition information may include all and / or part of the third message. For example, it may include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when (attempting) accessing the target cell, and the difference between the TCI status and / or beam information used when (attempting) accessing the target cell and the TCI status and / or beam information used when successfully accessing the target cell, etc.

[0319] In some implementations, for example, the eighth node may send LTM cell switching information to the fifth node when it detects the following:

[0320] - The UE access to the target cell cannot be detected using the TCI status and / or beam information received from the source node during the LTM process (e.g., a radio link failure occurred. For example, the radio link failure could be a handover failure), but the same UE access to the target cell during the aforementioned LTM process is subsequently detected using different TCI status and / or beam information.

[0321] - After a UE accesses the target cell, a radio link failure occurs. Subsequently, different TCI states and / or beam information are used to detect that the same UE accessed the target cell in the above LTM process.

[0322] - Beam failure recovery occurs after the UE accesses the target cell. In some implementations, this may be because the beam corresponding to the beam used by the UE to access the target cell is different from and / or the beam corresponding to the beam used by the UE after beam failure recovery is large.

[0323] Step 302G: The fifth node sends LTM cell transition information to the fourth node. The LTM transition information may be the aforementioned third message. In some implementations, for example, the LTM cell transition information may include all and / or part of the third message. For example, it may include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when attempting to access the target cell, and the difference between the TCI status and / or beam information used when attempting to access the target cell and the TCI status and / or beam information used when successfully accessing the target cell, etc.

[0324] In some implementations, for example, the fifth node may send LTM cell switching information to the fourth node when it detects the following situation, which can be referred to the situation exemplarily described in step 301G.

[0325] Step 303G: The fourth node sends LTM cell transition information to the third node. The LTM transition information may be the aforementioned third message. In some implementations, for example, the LTM cell transition information may include all and / or part of the third message. For example, it may include one or more of the following: UE identifier, Transmission Configuration Indicator (TCI) status and / or beam information used when successfully accessing the target cell, TCI status and / or beam information used when accessing the target cell fails, the difference between the TCI status and / or beam information used when accessing the target cell fails and the TCI status and / or beam information used when successfully accessing the target cell, the TCI status and / or beam information used when attempting to access the target cell, and the difference between the TCI status and / or beam information used when attempting to access the target cell and the TCI status and / or beam information used when successfully accessing the target cell, etc.

[0326] The third node analyzes the cause (which can be the cause of failure, a potential cause of failure, or a near-failure cause, or a successful handover with potential problems). In some implementations, for example, the third node can perform analysis based on information received from the fourth node and / or its own stored information. The third node performs self-optimization based on the received LTM conversion-related information. The self-optimization can be mobility robustness optimization. If the analyzed cause is beam information error and / or TCI status information error, for example, the beam selection and / or TCI status information settings can be optimized.

[0327] In the above embodiments, if it is a cell handover between cells under the same CU, the source node CU and the target node CU can be regarded as the same node.

[0328] In this disclosure, the embodiments are merely illustrative examples, and the above embodiments can be combined, etc.

[0329] In the examples above, for instance, in a non-gNB CU / gNB DU separate architecture, the gNB CU and gNB DU can be merged into a single node, such as the gNB. In this case, the interactions between the gNB CU and gNB DU can be considered as intra-node behaviors.

[0330] It should be understood that, depending on the application scenario, the various examples, aspects, methods, steps, processes, etc., described herein can be implemented individually or in combination in any manner, and this document does not impose any limitations. In this disclosure, for the sake of brevity, descriptions of specific steps in one example or embodiment are typically not repeated in corresponding steps of another example or embodiment. However, it should be understood that descriptions of specific steps in one example or embodiment can be applied to corresponding steps in any other example.

[0331] In one embodiment, the source gNB-DU needs to optimize the TA validity time.

[0332] During LTM preparation, the network side completes the LTM resource configuration preparation phase, sending an RRC reconfiguration message to the UE to configure the UE-side resources. Then, before the UE triggers LTM, optionally, to allow the UE to obtain the Timing Advance (TA) value with the candidate cell in advance, and thus perform a fast access procedure without RACH during LTM execution, the network side needs to perform an early TA acquisition process or the UE side needs to perform a TA measurement process. The mechanisms of these two methods are as follows:

[0333] Method 1 (Network-side triggering method): The source gNB-DU triggers the UE to send a preamble to the candidate cell via the PDCCH command. Then, the candidate cell calculates the TA information and sends it to the source gNB-DU via inter-network node signaling. When LTM is triggered, the source gNB-DU carries the TA of the target cell to the UE via the cell handover command MAC CE.

[0334] Method 2 (UE-side measurement method): The UE obtains the TA (Traffic Aspect) between the UE and candidate cells through measurement. In this method, the UE indicates its TA measurement capability to the network. Then, during LTM configuration, the network configures whether the UE can perform TA measurements based on the UE for each cell and other candidate cells. The network does not obtain the timing of the UE performing TA measurements based on the UE or the TA value of which candidate cell the UE has measured.

[0335] In one embodiment, when LTM is triggered, the UE obtains the TA of the target cell in advance through the aforementioned possible methods, and then the UE performs a RACH-less access procedure to the target cell. If the UE fails to perform a RACH-less access procedure (possibly due to an inaccurate, invalid, or expired TA), the UE will attempt to use the dedicated RACH resources carried in the cell handover command to perform a RACH-based access procedure to the target cell. If the RACH-based access procedure is successful, the target cell will send the TA value of successful RACH access to the gNB-CU, and the gNB-CU will send the successful access TA value to the source gNB-DU for optimization. However, the source gNB-DU may not send the TA of the target cell to the UE, or the TA used by the UE for RACH-less access may be obtained by the UE through measurement using method 2 described above. In this case, it would be unnecessary for the target cell to send the TA value information of successful RACH access to the source gNB-DU for TA validity time optimization. In this scenario, the problem isn't with the source gNB-DU (e.g., TA validity time). It could be that the source gNB-DU accurately determined an earlier TA to be invalid and therefore didn't send it to the UE, allowing the UE to directly access via RACH. Alternatively, it could be due to inaccurate, invalid, or expired TA measurements by the UE. Therefore, for scenarios where a UE initially fails to access the same target cell without RACH but then successfully accesses via RACH, network optimization is needed to avoid RACH-less access failures and unnecessary signaling transmissions between the target gNB-DU and gNB-CU, and between the gNB-CU and source gNB-DU. This is also important because the invalid TA might be caused by the UE or the target gNB-DU, and to prevent unnecessary optimization by the source DU that could negatively impact performance. The self-configuration and self-optimization method includes the following steps:

[0336] The source gNB-DU transmits the target cell's TA to the UE via the cell handover command MAC CE;

[0337] The source gNB-DU sends the target cell TA indication information to the gNB-CU, or the source gNB-DU sends the target cell TA sent to the UE to the gNB-CU, and the gNB-CU saves the received information.

[0338] The gNB CU sends the target cell's TA indication information to the UE, or the target cell's TA sent to the UE is sent to the target gNB-DU, and the gNB-DU saves the received information;

[0339] When the UE successfully accesses the target gNB-DU via the RACH procedure, the target gNB-DU sends the TA value based on the successful RACH access to the target cell to the gNB-CU.

[0340] The gNB CU sends a message to the source gNB-DU containing the TA value for successful RACH access to the target cell. This allows the source gNB-DU to optimize the TA validity period. The source gNB-DU optimizes the TA validity period based on the TA value for successful RACH access and the TA value for failed RACH access.

[0341] In this method, the failure can be caused by the gNB-CU detecting that the TA is invalid or expired, or by the source gNB-DU detecting that the TA is invalid or expired. If the failure is caused by the gNB-CU detecting that the TA is invalid or expired, then the message sent by the gNB-CU to the source gNB-DU also includes the invalid TA as the type of failure.

[0342] Optionally, the source gNB-DU can send an indication that a TA (Target Transfer Protocol) for the target cell has been sent, or the TA for the target cell sent to the UE, to the gNB-CU via an F1AP DU-CU Cell Switch Notification message or other messages. The gNB-CU can then send the same indication or the same TA for the target cell sent to the UE, to the target gNB-DU via a CU-DU Cell Switch Notification message or other messages. The indication that a TA for the target cell has been sent can also be named differently, such as "Early TA Delivery to UE," indicating that the source gNB-DU carried the TA for the target cell to the UE via a cell handover command. The target gNB-DU will save this indication upon receiving it. If the target gNB-DU knows that the UE first experiences a RACH-less access failure and then successfully accesses via RACH, the target DU determines that the problem might be caused by an invalid or inaccurate early TA sent by the target gNB-DU and will perform self-optimization. If the target gNB-DU determines that the problem is not with the target gNB-DU, then it is likely a problem with the source gNB-DU. In this case, the target gNB-DU will send an F1AP message to the gNB-CU, which will then send a message to the source gNB-DU containing the TA value for successful RACH-based access. This allows the source gNB-DU to optimize the early TA validity time based on the TA value for successful RACH-based access and the TA value for the RACH-less access failure. Optionally, the target gNB-DU can notify the gNB-CU of the RACH-based successful access TA value via an F1AP access success message or other messages. Then, the gNB-CU can notify the source gNB-DU of the aforementioned TA value via a UE context release command, a UE context modification request message, or other messages.

[0343] In one embodiment, if an indication message (indicating that the source gNB-DU sent an early TA of the target cell to the UE when LTM was triggered) or an early TA is included in the DU-CU cell handover notification message, the gNB-CU should forward this indication message to the target gNB-DU via the CU-DU cell handover notification message, if supported.

[0344] In one embodiment, if an indication (indicating that the source gNB-DU sent an early TA of the target cell to the UE when LTM was triggered) or an early TA is included in the CU-DU cell handover notification message, the target gNB-DU should store this indication information, if supported, and consider this information when performing LTM mobility robustness optimization. For example, if a RACH-based access success occurs after a RACH-less access failure, the target gNB-DU sends the RACH-based access success TA value to the source gNB-DU via the gNB-CU.

[0345] In one embodiment, if the target gNB-DU sends a TA value based on RACH access success to the gNB-CU, this TA value information is included in the access success message or other messages, and if supported, the gNB-CU should forward this TA information to the source gNB-DU.

[0346] In one embodiment, if the source gNB-DU receives a TA value based on successful RACH access, this information is included in the UE context release command or UE context modification request message. If supported, the source gNB-DU should consider comparing it with the TA obtained in an earlier TA procedure and then perform the corresponding LTM mobility robustness optimization (such as optimizing the TA validity period).

[0347] Next, Figure 4A A flowchart of a method 400 performed by a fifth node in a wireless communication system according to an embodiment of the present disclosure is shown.

[0348] like Figure 4AAs shown, the method 400 executed by a fifth node in a wireless communication system according to an embodiment of this disclosure may include: in step S401, receiving first information from a fourth node, wherein the first information includes at least one of the following: information related to the acquisition method of the timing advance TA used by the user equipment UE to access the target cell, a first TA for the UE to access the target cell, a first transmission configuration indication (TCI) state for the UE to access the target cell, first beam information for the UE to access the target cell, information related to the UE simultaneously configuring conditional handover and Layer 1 / Layer 2 triggered mobility LTM handover, and information related to the handover triggering status of the UE; in step S402 In step S403, the UE receives second information from the eighth node, wherein the second information includes at least one of the following: the second TA used when the UE successfully accesses the target cell, the third TA used when the UE fails to access the target cell, the second TCI state used when the UE successfully accesses the target cell, the third TCI state used when the UE fails to access the target cell, the second beam information used when the UE successfully accesses the target cell, and the third beam information used when the UE fails to access the target cell; and in step S403, the UE sends third information to the fourth node, wherein the third information includes at least one of the following: the first information and the second information.

[0349] According to embodiments of this disclosure, the third information is used for self-optimization of the fourth node, wherein the self-optimization includes mobility robustness optimization.

[0350] According to an embodiment of this disclosure, the third information is sent from the fourth node to the third node, wherein the third information is used by the third node to perform self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0351] According to embodiments of this disclosure, the method for obtaining the TA used by the UE to access the target cell includes at least one of the following: the TA is a TA calculated by the UE; the TA is a TA received by the UE from a third node; the TA is a TA obtained by the UE through random access.

[0352] According to embodiments of this disclosure, the information related to the triggering of the handover of the UE includes at least one of the following: the handover is based on Layer 1 measurement results; the handover is based on Layer 3 measurement results; the handover is triggered by a source node centralized unit (CU); the handover is triggered by a source node distributed unit (DU); the handover is triggered by a source node DU based on Layer 3 measurement results, wherein, in the case where the handover is triggered by a source node CU, the third information is used by the fourth node for self-optimization, wherein, in the case where the handover is triggered by a source node DU, the third information is sent from the fourth node to the third node, and wherein the third information is used by the third node for self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0353] According to embodiments of this disclosure, the third information further includes the handover failure reason and / or potential handover failure reason of the UE, wherein the handover failure reason and / or potential handover failure reason of the UE is determined based on the first information and / or the second information, wherein the handover failure reason and / or potential handover failure reason of the UE includes at least one of the following: beam error used by the UE to access the target cell, TCI state error used by the UE to access the target cell, TA failure used by the UE to access the target cell, TA failure received by the UE, and TA failure calculated by the UE.

[0354] According to embodiments of this disclosure, determining the handover failure cause and / or potential handover failure cause of the UE includes at least one of the following: if the difference between the third TA and the second TA is greater than or equal to a first threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the first TA and the second TA is greater than or equal to a second threshold, the potential handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the identifier of the third TCI state and the identifier of the second TCI state is greater than or equal to a third threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell. The TCI state used by the UE to access the target cell is incorrect; if the difference between the identifier of the first TCI state and the identifier of the second TCI state is greater than or equal to a fourth threshold, the potential handover failure reason of the UE is determined to be the TCI state used by the UE to access the target cell being incorrect; if the difference between the third beam information and the second beam information is greater than or equal to a fifth threshold, the handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell; if the difference between the first beam information and the second beam information is greater than or equal to a sixth threshold, the potential handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell.

[0355] According to embodiments of this disclosure, the third information further includes at least one of the following: the difference between the third TA and the second TA, the difference between the first TA and the second TA, the difference between the identifier of the third TCI state and the identifier of the second TCI state, the difference between the identifier of the first TCI state and the identifier of the second TCI state, the difference between the third beam information and the second beam information, and the difference between the first beam information and the second beam information.

[0356] Figure 4B A flowchart of a method 410 performed by a fourth node in a wireless communication system according to an embodiment of the present disclosure is shown.

[0357] like Figure 4BAs shown, the method 410 executed by a fourth node in a wireless communication system according to an embodiment of this disclosure may include: in step S411, sending first information to a fifth node, wherein the first information includes at least one of the following: information related to the acquisition method of the timing advance TA used by the user equipment UE to access the target cell, a first TA for the UE to access the target cell, a first transmission configuration indication (TCI) state for the UE to access the target cell, first beam information for the UE to access the target cell, information related to the UE being simultaneously configured with conditional handover and Layer 1 / Layer 2 triggered mobility LTM handover, and information related to the handover triggering status of the UE; and in step S412, receiving third information from the fifth node, wherein the third information includes at least one of the following: the first information and the second information. In some implementations, the second information is sent from the eighth node to the fifth node, wherein the second information includes at least one of the following: the second TA used when the UE successfully accesses the target cell, the third TA used when the UE fails to access the target cell, the second TCI state used when the UE successfully accesses the target cell, the third TCI state used when the UE fails to access the target cell, the second beam information used when the UE successfully accesses the target cell, and the third beam information used when the UE fails to access the target cell.

[0358] According to embodiments of this disclosure, the third information is used for self-optimization of the fourth node, wherein the self-optimization includes mobility robustness optimization.

[0359] According to an embodiment of this disclosure, the method further includes: sending the third information to a third node, wherein the third information is used by the third node to perform self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0360] According to embodiments of this disclosure, the method for obtaining the TA used by the UE to access the target cell includes at least one of the following: the TA is a TA calculated by the UE; the TA is a TA received by the UE from a third node; the TA is a TA obtained by the UE through random access.

[0361] According to embodiments of this disclosure, the information related to the triggering of the handover of the UE includes at least one of the following: the handover is based on Layer 1 measurement results; the handover is based on Layer 3 measurement results; the handover is triggered by a source node centralized unit (CU); the handover is triggered by a source node distributed unit (DU); the handover is triggered by a source node DU based on Layer 3 measurement results, wherein, in the case where the handover is triggered by a source node CU, the third information is used by the fourth node for self-optimization, wherein, in the case where the handover is triggered by a source node DU, the third information is sent from the fourth node to the third node, and wherein the third information is used by the third node for self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0362] According to embodiments of this disclosure, the third information further includes the handover failure reason and / or potential handover failure reason of the UE, wherein the handover failure reason and / or potential handover failure reason of the UE is determined based on the first information and / or the second information, wherein the handover failure reason and / or potential handover failure reason of the UE includes at least one of the following: beam error used by the UE to access the target cell, TCI state error used by the UE to access the target cell, TA failure used by the UE to access the target cell, TA failure received by the UE, and TA failure calculated by the UE.

[0363] According to embodiments of this disclosure, determining the handover failure cause and / or potential handover failure cause of the UE includes at least one of the following: if the difference between the third TA and the second TA is greater than or equal to a first threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the first TA and the second TA is greater than or equal to a second threshold, the potential handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the identifier of the third TCI state and the identifier of the second TCI state is greater than or equal to a third threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell. The TCI state used by the UE to access the target cell is incorrect; if the difference between the identifier of the first TCI state and the identifier of the second TCI state is greater than or equal to a fourth threshold, the potential handover failure reason of the UE is determined to be the TCI state used by the UE to access the target cell being incorrect; if the difference between the third beam information and the second beam information is greater than or equal to a fifth threshold, the handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell; if the difference between the first beam information and the second beam information is greater than or equal to a sixth threshold, the potential handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell.

[0364] According to embodiments of this disclosure, the third information further includes at least one of the following: the difference between the third TA and the second TA, the difference between the first TA and the second TA, the difference between the identifier of the third TCI state and the identifier of the second TCI state, the difference between the identifier of the first TCI state and the identifier of the second TCI state, the difference between the third beam information and the second beam information, and the difference between the first beam information and the second beam information.

[0365] Figure 4C A flowchart of a method 420 performed by a user equipment (UE) in a wireless communication system according to an embodiment of the present disclosure is shown.

[0366] like Figure 4CAs shown, a method 420 performed by a user equipment (UE) in a wireless communication system according to an embodiment of this disclosure may include: receiving a request for a wireless link failure report from a fifth node in step S421; and sending the wireless link failure report to the fifth node in step S422. In some embodiments, first information is sent from a fourth node to the fifth node, wherein the first information includes at least one of the following: information related to the acquisition method of the timing advance TA used by the UE to access the target cell, a first TA for the UE to access the target cell, a first transmission configuration indication (TCI) state for the UE to access the target cell, first beam information for the UE to access the target cell, information related to the UE simultaneously configuring conditional handover and Layer 1 / Layer 2 triggered mobility LTM handover, and information related to the handover triggering status of the UE. In some embodiments, the second information is sent from the eighth node to the fifth node, wherein the second information includes at least one of the following: a second TA used when the UE successfully accesses the target cell, a third TA used when the UE fails to access the target cell, a second TCI state used when the UE successfully accesses the target cell, a third TCI state used when the UE fails to access the target cell, second beam information used when the UE successfully accesses the target cell, and third beam information used when the UE fails to access the target cell. In some embodiments, the third information is sent from the fifth node to the fourth node, wherein the third information includes at least one of the following: the first information and the second information.

[0367] According to embodiments of this disclosure, the third information is used for self-optimization of the fourth node, wherein the self-optimization includes mobility robustness optimization.

[0368] According to an embodiment of this disclosure, the third information is sent from the fourth node to the third node, wherein the third information is used by the third node to perform self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0369] According to embodiments of this disclosure, the method for obtaining the TA used by the UE to access the target cell includes at least one of the following: the TA is a TA calculated by the UE; the TA is a TA received by the UE from a third node; the TA is a TA obtained by the UE through random access.

[0370] According to embodiments of this disclosure, the information related to the triggering of the handover of the UE includes at least one of the following: the handover is based on Layer 1 measurement results; the handover is based on Layer 3 measurement results; the handover is triggered by a source node centralized unit (CU); the handover is triggered by a source node distributed unit (DU); the handover is triggered by a source node DU based on Layer 3 measurement results, wherein, in the case where the handover is triggered by a source node CU, the third information is used by the fourth node for self-optimization, wherein, in the case where the handover is triggered by a source node DU, the third information is sent from the fourth node to the third node, and wherein the third information is used by the third node for self-optimization, wherein the self-optimization includes mobility robustness optimization.

[0371] According to embodiments of this disclosure, the third information further includes the handover failure reason and / or potential handover failure reason of the UE, wherein the handover failure reason and / or potential handover failure reason of the UE is determined based on the first information and / or the second information, wherein the handover failure reason and / or potential handover failure reason of the UE includes at least one of the following: beam error used by the UE to access the target cell, TCI state error used by the UE to access the target cell, TA failure used by the UE to access the target cell, TA failure received by the UE, and TA failure calculated by the UE.

[0372] According to embodiments of this disclosure, determining the handover failure cause and / or potential handover failure cause of the UE includes at least one of the following: if the difference between the third TA and the second TA is greater than or equal to a first threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the first TA and the second TA is greater than or equal to a second threshold, the potential handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell; if the difference between the identifier of the third TCI state and the identifier of the second TCI state is greater than or equal to a third threshold, the handover failure cause of the UE is determined to be a failure of the TA used by the UE to access the target cell. The TCI state used by the UE to access the target cell is incorrect; if the difference between the identifier of the first TCI state and the identifier of the second TCI state is greater than or equal to a fourth threshold, the potential handover failure reason of the UE is determined to be the TCI state used by the UE to access the target cell being incorrect; if the difference between the third beam information and the second beam information is greater than or equal to a fifth threshold, the handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell; if the difference between the first beam information and the second beam information is greater than or equal to a sixth threshold, the potential handover failure reason of the UE is determined to be the beam error used by the UE to access the target cell.

[0373] According to embodiments of this disclosure, the third information further includes at least one of the following: the difference between the third TA and the second TA, the difference between the first TA and the second TA, the difference between the identifier of the third TCI state and the identifier of the second TCI state, the difference between the identifier of the first TCI state and the identifier of the second TCI state, the difference between the third beam information and the second beam information, and the difference between the first beam information and the second beam information.

[0374] It should be understood that methods 400, 410, 420, etc., according to embodiments of this disclosure may also include any steps described in conjunction with the various examples, aspects, drawings, etc. of this disclosure.

[0375] Next, Figure 5 A schematic diagram of node 500 according to an embodiment of the present disclosure is shown.

[0376] like Figure 5As shown, a node (or node device) 500 according to an embodiment of this disclosure may include a transceiver 510 and a processor 520. The transceiver 510 may be configured to transmit and receive signals. The processor 520 may be coupled to the transceiver 510 and may be configured (e.g., to control the transceiver 510) to perform methods executed by any node according to an embodiment of this disclosure.

[0377] Figure 6 A schematic diagram of a user equipment (UE) 600 according to an embodiment of the present disclosure is shown.

[0378] like Figure 6 As shown, a user equipment (UE) 600 according to an embodiment of this disclosure may include a transceiver 610 and a processor 620. The transceiver 610 may be configured to transmit and receive signals. The processor 620 may be coupled to the transceiver 610 and may be configured (e.g., to control the transceiver 610) to perform methods executed by the user equipment (UE) according to an embodiment of this disclosure. In this disclosure, the processor may also be referred to as a controller.

[0379] Embodiments of this disclosure also provide a computer-readable medium having computer-readable instructions stored thereon, which, when executed by a processor, can be used to implement any method according to embodiments of this disclosure.

[0380] Various embodiments of this disclosure can be implemented as computer-readable code embodied on a computer-readable recording medium from a particular perspective. A computer-readable recording medium is any data storage device capable of storing data readable by a computer system. Examples of computer-readable recording media may include read-only memory (ROM), random access memory (RAM), optical disc read-only memory (CD-ROM), magnetic tape, floppy disk, optical data storage device, carrier wave (e.g., data transmission via the Internet), and the like. Computer-readable recording media can be distributed via computer systems connected via a network, and thus computer-readable code can be stored and executed in a distributed manner. Furthermore, the functional programs, code, and code segments used to implement the various embodiments of this disclosure can be readily interpreted by those skilled in the art applying the embodiments of this disclosure.

[0381] It will be understood that embodiments of this disclosure can be implemented in hardware, software, or a combination of hardware and software. Software can be stored as processor-executable program instructions or computer-readable code on a non-transitory computer-readable medium. Examples of non-transitory computer-readable recording media include magnetic storage media (e.g., ROM, floppy disk, hard disk, etc.) and optical recording media (e.g., CD-ROM, digital video disc (DVD), etc.). Non-transitory computer-readable recording media can also be distributed across a network-coupled computer system, such that the computer-readable code is stored and executed in a distributed manner. The medium can be read by a computer, stored in memory, and executed by a processor. Various embodiments can be implemented by a computer or a portable terminal including a controller and memory, and the memory can be an example of a non-transitory computer-readable recording medium suitable for storing a program(s) having instructions for implementing embodiments of this disclosure. This disclosure can be implemented by a program having code for specifically implementing the apparatus and methods described in the claims, the program being stored in a machine (or computer)-readable storage medium. The program can be carried electronically on any medium, such as communication signals transmitted via wired or wireless connections, and this disclosure suitably includes its equivalents.

[0382] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any person skilled in the art can make various changes or substitutions within the technical scope disclosed in this disclosure, and such changes or substitutions should all be covered within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A method performed by a fifth node in a wireless communication system, comprising: Receive first information from the fourth node, wherein the first information includes at least one of the following: information related to the acquisition method of the advance timing TA used by the user equipment (UE) to access the target cell, the first TA for the UE to access the target cell, the first transmission configuration indication (TCI) state for the UE to access the target cell, the first beam information for the UE to access the target cell, information related to the UE being configured with both conditional handover and Layer 1 / Layer 2 triggered mobility LTM handover, and information related to the handover triggering status of the UE; The second information is received from the eighth node, wherein the second information includes at least one of the following: a second TA used when the UE successfully accesses the target cell, a third TA used when the UE fails to access the target cell, a second TCI state used when the UE successfully accesses the target cell, a third TCI state used when the UE fails to access the target cell, a second beam information used when the UE successfully accesses the target cell, and a third beam information used when the UE fails to access the target cell; and Send third information to the fourth node, wherein the third information includes at least one of the following: the first information and the second information.

2. The method according to claim 1, wherein, The third information is used by the fourth node for self-optimization, wherein the self-optimization includes mobility robustness optimization.

3. The method according to claim 1, wherein, The third information is sent from the fourth node to the third node. The third information is used for the third node to perform self-optimization, which includes mobility robustness optimization.

4. The method according to claim 1, wherein, The method for obtaining the TA used by the UE to access the target cell includes at least one of the following: The TA is the TA calculated by the UE; The TA is the TA received by the UE from the third node; The TA is the TA obtained by the UE through random access.

5. The method according to claim 1, wherein, The information related to the triggering of the handover of the UE includes at least one of the following: The switching is based on the layer 1 measurement results; The switching is based on the layer 3 measurement results; The switching is triggered by the source node centralized unit (CU); The switching is triggered by the source node distribution unit (DU). The switching is triggered by the source node DU based on the layer 3 measurement results. Specifically, when the switching is triggered by the source node CU, the third information is used by the fourth node for self-optimization. Wherein, if the switch is triggered by the source node DU, the third information is sent from the fourth node to the third node, and wherein the third information is used by the third node for self-optimization. The self-optimization includes mobility robustness optimization.

6. The method according to claim 1, wherein, The third information also includes the reason for the UE's handover failure and / or potential reasons for handover failure. The handover failure reason and / or potential handover failure reason of the UE is determined based on the first information and / or the second information. The handover failure reasons and / or potential handover failure reasons of the UE include at least one of the following: The beam used by the UE to access the target cell is incorrect, the TCI status used by the UE to access the target cell is incorrect, the TA used by the UE to access the target cell is invalid, the TA received by the UE is invalid, and the TA calculated by the UE is invalid.

7. The method according to claim 6, wherein, The determination of the handover failure cause and / or potential handover failure cause of the UE includes at least one of the following: If the difference between the third TA and the second TA is greater than or equal to the first threshold, the reason for the UE's handover failure is determined to be that the TA used by the UE to access the target cell has failed. If the difference between the first TA and the second TA is greater than or equal to the second threshold, the potential handover failure reason of the UE is determined to be the failure of the TA used by the UE to access the target cell; If the difference between the identifier of the third TCI state and the identifier of the second TCI state is greater than or equal to the third threshold, the reason for the UE's handover failure is determined to be that the TCI state used by the UE to access the target cell is incorrect. If the difference between the identifier of the first TCI state and the identifier of the second TCI state is greater than or equal to the fourth threshold, the potential handover failure reason of the UE is determined to be that the TCI state used by the UE to access the target cell is incorrect. If the difference between the third beam information and the second beam information is greater than or equal to the fifth threshold, the reason for the UE's handover failure is determined to be an error in the beam used by the UE to access the target cell. If the difference between the first beam information and the second beam information is greater than or equal to the sixth threshold, the potential handover failure reason of the UE is determined to be an error in the beam used by the UE to access the target cell.

8. The method according to claim 1, wherein, The third information also includes at least one of the following: The difference between the third TA and the second TA, the difference between the first TA and the second TA, the difference between the identifier of the third TCI state and the identifier of the second TCI state, the difference between the identifier of the first TCI state and the identifier of the second TCI state, the difference between the third beam information and the second beam information, and the difference between the first beam information and the second beam information.

9. A method performed by a fourth node in a wireless communication system, comprising: Send first information to the fifth node, wherein the first information includes at least one of the following: information related to the acquisition method of the advance timing reference (TA) used by the user equipment (UE) to access the target cell; a first TA for the UE to access the target cell; a first transmission configuration indication (TCI) state for the UE to access the target cell; first beam information for the UE to access the target cell; information related to the UE being simultaneously configured with conditional handover and Layer 1 / Layer 2 triggered mobility LTM handover; and information related to the handover triggering status of the UE; and The third information is received from the fifth node, wherein the third information includes at least one of the following: the first information, the second information, The second information is sent from the eighth node to the fifth node, and the second information includes at least one of the following: the second TA used when the UE successfully accesses the target cell, the third TA used when the UE fails to access the target cell, the second TCI state used when the UE successfully accesses the target cell, the third TCI state used when the UE fails to access the target cell, the second beam information used when the UE successfully accesses the target cell, and the third beam information used when the UE fails to access the target cell.

10. A method performed by a user equipment (UE) in a wireless communication system, comprising: Receive a request for a wireless link failure report from the fifth node; as well as Send the wireless link failure report to the fifth node. The first information is sent from the fourth node to the fifth node, and the first information includes at least one of the following: information related to the acquisition method of the timing advance TA used by the UE to access the target cell, the first TA for the UE to access the target cell, the first transmission configuration indication (TCI) status for the UE to access the target cell, the first beam information for the UE to access the target cell, information related to the UE being configured with both conditional handover and Layer 1 / Layer 2 triggered mobility LTM handover, and information related to the handover triggering status of the UE. The second information is sent from the eighth node to the fifth node, and includes at least one of the following: the second TA used when the UE successfully accesses the target cell, the third TA used when the UE fails to access the target cell, the second TCI state used when the UE successfully accesses the target cell, the third TCI state used when the UE fails to access the target cell, the second beam information used when the UE successfully accesses the target cell, and the third beam information used when the UE fails to access the target cell; and The third information is sent from the fifth node to the fourth node, and the third information includes at least one of the following: the first information, the second information, the difference between the third TA and the second TA, the difference between the first TA and the second TA, the difference between the identifier of the third TCI state and the identifier of the second TCI state, the difference between the identifier of the first TCI state and the identifier of the second TCI state, the difference between the third beam information and the second beam information, and the difference between the first beam information and the second beam information.

11. The method according to claim 10, wherein, The third information is used by the fourth node for self-optimization, wherein the self-optimization includes mobility robustness optimization.

12. The method according to claim 10, wherein, The third information is sent from the fourth node to the third node. The third information is used for the third node to perform self-optimization, which includes mobility robustness optimization.

13. The method according to claim 10, wherein, The method for obtaining the TA used by the UE to access the target cell includes at least one of the following: The TA is the TA calculated by the UE; The TA is the TA received by the UE from the third node; The TA is the TA obtained by the UE through random access.

14. The method of claim 10, wherein, The information related to the triggering of the handover of the UE includes at least one of the following: The switching is based on the layer 1 measurement results; The switching is based on the layer 3 measurement results; The switching is triggered by the source node centralized unit (CU); The switching is triggered by the source node distribution unit (DU). The switching is triggered by the source node DU based on the layer 3 measurement results. Specifically, when the switching is triggered by the source node CU, the third information is used by the fourth node for self-optimization. Wherein, if the switch is triggered by the source node DU, the third information is sent from the fourth node to the third node, and wherein the third information is used by the third node for self-optimization. The self-optimization includes mobility robustness optimization.

15. The method according to claim 10, wherein, The third information also includes the reason for the UE's handover failure and / or potential reasons for handover failure. The handover failure reason and / or potential handover failure reason of the UE is determined based on the first information and / or the second information. The handover failure reasons and / or potential handover failure reasons of the UE include at least one of the following: The following are errors: the beam used by the UE to access the target cell is incorrect; the TCI state used by the UE to access the target cell is incorrect; the TA used by the UE to access the target cell is invalid; the TA received by the UE is invalid; the TA calculated by the UE is invalid. The determination of the handover failure reason and / or potential handover failure reason of the UE includes at least one of the following: If the difference between the third TA and the second TA is greater than or equal to the first threshold, the reason for the UE's handover failure is determined to be that the TA used by the UE to access the target cell has failed. If the difference between the first TA and the second TA is greater than or equal to the second threshold, the potential handover failure reason of the UE is determined to be the failure of the TA used by the UE to access the target cell; If the difference between the identifier of the third TCI state and the identifier of the second TCI state is greater than or equal to the third threshold, the reason for the UE's handover failure is determined to be that the TCI state used by the UE to access the target cell is incorrect. If the difference between the identifier of the first TCI state and the identifier of the second TCI state is greater than or equal to the fourth threshold, the potential handover failure reason of the UE is determined to be that the TCI state used by the UE to access the target cell is incorrect. If the difference between the third beam information and the second beam information is greater than or equal to the fifth threshold, the reason for the UE's handover failure is determined to be an error in the beam used by the UE to access the target cell. If the difference between the first beam information and the second beam information is greater than or equal to the sixth threshold, the potential handover failure reason of the UE is determined to be an error in the beam used by the UE to access the target cell.

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