Link failure report method and user equipment

Abstract

The present disclosure provides a link failure report method and a user equipment. The link failure report method comprises: a user equipment (UE) initiates a radio resource control (RRC) re-establishment process and executes a cell selection process; and if the UE determines that a selected cell is a layer 1 / layer 2 triggered mobility (LTM) candidate cell, the UE saves LTM-related information in a failure report, the LTM-related information at least comprising: information used for indicating the selected LTM candidate cell.

Description

Link failure reporting method and user equipment Technical Field

[0001] The present disclosure relates to the technical field of wireless communications, and more particularly, to a link failure reporting method and corresponding user equipment. Background Art

[0002] Network optimization in wireless networks can achieve the goal of optimizing network performance. Data collection and analysis are typically performed on existing deployed and operational networks to identify factors affecting network quality. Network performance can then be improved by modifying configured network parameters, adjusting network structure, and adjusting deployed equipment. Self-configuration and self-optimization networks (SON) refer to the process of automatically adjusting the network based on user equipment and / or base station measurements and performance measurements. The network can configure UEs to perform measurements for SON. SON functions include many aspects, such as the Automatic Neighbor Relation (ANR) function, which reduces the operator's burden of neighbor management; Mobility Load Balancing (MLB), which balances load between different cells; Mobility Robustness Optimization (MRO), which optimizes mobility performance; Random Access Channel Optimization, which optimizes random access channel parameters; and Radio Link Failure Reporting (RLFR), which optimizes coverage and MRO.

[0003] Furthermore, Minimization of Drive Tests (MDT) technology is also a key tool for operators to optimize their networks. By extracting relevant network optimization parameters from drive test data collected from UEs, operators can analyze this data to understand the status of network deployment and operations, enabling them to make decisions on how to improve network operations. MDT's primary application scenarios include coverage optimization, capacity optimization, mobility management optimization, QoS parameter optimization, and common channel parameter configuration optimization.

[0004] In NR systems of Release 18 and earlier versions, the Radio Link Failure (RLF) report is used to record relevant information on the UE side when a link failure occurs, so that the network side can diagnose and optimize problems or parameters such as network coverage, mobility robustness parameters, and random access process configuration.

[0005] The Layer 1 / L2-triggered mobility (LTM) mechanism was introduced in the NR system of version 18. The purpose of this mechanism is to reduce mobility delay. In the NR system before version 18, mobility was mainly achieved through handover (i.e., synchronous reconfiguration) triggered by Radio Resource Control (RRC) layer signaling based on Layer 3 measurement results. During the handover process, the UE releases the source service cell and then adds the target service cell, and needs to perform a complete Layer 2 and Layer 1 reset operation. This results in a longer delay in the mobility process, higher overhead, and longer data interruption time. In the LTM mechanism, the RRC configuration of the target candidate cell is sent to the UE in advance, and the subsequent cell change is triggered through Layer 1 or Layer 2 signaling based on the Layer 1 measurement results, thereby achieving the purpose of reducing delay, overhead, and interruption time.

[0006] The present disclosure aims to solve the link failure reporting problem in NR networks, and further, to solve the link failure reporting problem in networks supporting LTM. Summary of the Invention

[0007] The main purpose of the present disclosure is to provide a link failure reporting method and user equipment to realize the reporting of LTM-related link failure information in a system supporting LTM and the setting problem of failure information when realizing failure information reporting in an LTM scenario.

[0008] According to a first aspect of the present disclosure, a link failure reporting method is provided, comprising: a user equipment (UE) detecting a link failure, initiating a radio resource control (RRC) re-establishment process, and performing a cell selection process during the RRC re-establishment process; when the following conditions are met: the RRC re-establishment process is triggered by a radio link failure of a master cell group (MCG) or a synchronization reconfiguration failure of the MCG or a mobility failure from a next generation wireless system (NR); the UE is enabled with a link recovery function based on an LTM configuration; the cell selected in the cell selection process is an LTM candidate cell of an MCG for layer 1 and layer 2 triggered mobility; the UE performs a Cell Switch execution process to the selected cell, and the UE includes information on the selected LTM candidate cell in a link failure report.

[0009] In the link failure reporting method of the first aspect above, the information of the selected LTM candidate cell is the LTM cell identifier, and the UE sets a field in the link failure report to include the LTM cell identifier; when the global cell identifier is valid, the LTM cell identifier is set to the global cell identifier, otherwise the cell identifier is set to the physical cell identifier and carrier frequency.

[0010] In the link failure reporting method of the first aspect, the setting of the LTM cell identifier is to include a new LTM cell identifier in an LTM cell identifier list.

[0011] In the link failure reporting method of the first aspect, when the selected cell is the cell selected in the first cell selection process after detecting the link failure, the LTM cell identifier is set as the cell identifier of the selected cell.

[0012] In the link failure reporting method of the first aspect above, when the LTM cell identifier in the link failure report has not been set, the LTM cell identifier is set to the cell identifier of the selected cell; otherwise, the set LTM cell identifier in the link failure report is replaced with the cell identifier of the selected cell.

[0013] In the link failure reporting method of the first aspect above, the link recovery function enabled based on LTM configuration is configured with an attemptLTM-Switch information element; the attemptLTM-Switch information element is used to indicate that the UE should perform an LTM cell change when the selected cell is an LTM candidate cell.

[0014] In the link failure reporting method of the first aspect, the selected cell is an LTM candidate cell of an MCG, which means that the selected cell is one of one or more LTM candidate cells in the LTM configuration associated with the MCG.

[0015] In the link failure reporting method of the first aspect, when the UE supports link failure reporting for LTM, the UE includes information of the selected LTM candidate cell in the link failure report.

[0016] According to a second aspect of the present disclosure, a user equipment is provided, comprising: a processor; and a memory storing instructions; wherein the instructions, when executed by the processor, execute the above-mentioned link failure reporting method.

[0017] Effects of the Invention

[0018] According to the link failure reporting method performed by the user equipment and the user equipment disclosed in the present invention, in a system supporting LTM, when the UE realizes failed link recovery through the candidate cell of LTM, the relevant information of the link recovery based on LTM is reported, so that the network side can obtain the LTM characteristic information related to the link recovery, thereby obtaining more link failure related information, based on which the cause of the link failure is determined, and the setting of the relevant mobility parameters is optimized to avoid or reduce link failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other features of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0020] FIG1 is a schematic flow chart showing a cell switch process based on the LTM mechanism.

[0021] FIG2 is a schematic flow chart showing a link failure reporting method in embodiment 1 of the present invention.

[0022] FIG3 is a schematic flow chart showing a link failure reporting method in embodiment 2 of the present invention.

[0023] FIG4 is a schematic flow chart showing a link failure reporting method in embodiment 3 of the present invention.

[0024] FIG5 shows a block diagram of a user equipment according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description of exemplary embodiments of the disclosure, taken in conjunction with the accompanying drawings.

[0026] In this specification, the various embodiments described below for describing the principles of the present disclosure are merely illustrative and should not be construed in any way as limiting the scope of the disclosure. The following description with reference to the accompanying drawings is intended to assist in a comprehensive understanding of the exemplary embodiments of the present disclosure as defined by the claims and their equivalents. The following description includes a variety of specific details to aid understanding, but these details should be considered merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, for the sake of clarity and brevity, descriptions of well-known functions and structures have been omitted. In addition, throughout the drawings, the same reference numerals are used for similar functions and operations.

[0027] In this disclosure, the terms "include" and "contain" and their derivatives are intended to include but not limit; the term "or" is inclusive, meaning and / or. "If", "if", "in the case of" and "when" are interchangeable.

[0028] The following describes several embodiments of the present disclosure using the NR mobile communication system as an example application environment. However, it should be noted that the present disclosure is not limited to the following embodiments, but is applicable to many other wireless communication systems, such as an LTE system connected to a 5G core network.

[0029] The base station in this disclosure can be any type of base station, including an enhanced eNB, a 5G communication system gNB, or a micro base station, pico base station, macro base station, or home base station. The network side generally refers to a base station or cell. Unless otherwise specified, cell, beam, transmission point (TRP), base station, and cell group are interchangeable. A base station can also refer to the gNB-Central Unit (gNB-CU) or gNB-Distributed Unit (gNB-DU) that constitutes a base station. Unless otherwise specified, different embodiments can be combined. For example, the same variables, parameters, and terms in different embodiments have the same interpretation. Cancel, release, delete, clear, and purge are interchangeable. Execute, use, and apply are interchangeable. Configure and reconfigure are interchangeable. Monitor and detect are interchangeable. Initiate and trigger are interchangeable.

[0030] The following first describes some existing mechanisms / prior technologies involved in the present disclosure. It is worth noting that some of the names in the following description are only illustrative and not restrictive, and other names may also be used.

[0031] Existing wireless link failure reporting mechanism:

[0032] In the NR system, the UE will generate and save a radio link failure report (RLF Report) when a radio link failure (RLF) or handover failure (HOF) occurs, and save the radio link failure information in the UE variable VarRLF-Report. Generally, the UE only saves the RLF information of the most recent connection failure (RLF or HOF) in the RLF report. After restoring the connection with the network side (such as through the RRC re-establishment process or the RRC establishment process for establishing a new connection), the UE can inform the network side through an RRC message that there is a valid radio link failure report (such as indicated by the rlf-InfoAvailable information element). After receiving the indication, the network side can request the UE to report its saved radio link failure report through an RRC message (such as the rlf-ReportReq information element in the UE information request UEInformationRequest message to indicate the request). The UE will report the saved RLF report (rlf-Report information element in the UE information response UEInformationResponse message) to the network side in the response RRC message. The radio link failure report obtained by the network side is used for network optimization, such as network coverage and mobile robustness optimization. The RLF report contains information related to the link failure, including the identifier and measurement results of the source cell, target cell or neighbor cell when the link failure occurs, location information, link failure type (RLF or HOF), RLF reason, the time from connection failure to RLF report reporting (recorded as timeSinceFailure information element), the time from the last receipt of the handover command (handover initiation or handover execution) to the connection failure (recorded as timeConnFailure information element), the time between the next UE entering the RRC connection state after the connection failure and the re-establishment process fails (recorded as timeUntilReconnection information element), RRC re-establishment cell identifier, random access process information performed before the link failure, etc. RLF and HOF are collectively referred to as connection failure or link failure.

[0033] LTM mechanism:

[0034] Traditional handovers are triggered by Layer 3 handover commands (i.e., RRC reconfiguration messages containing synchronization reconfiguration information elements). To reduce data interruptions during mobility, the 3GPP working group introduced the LTM mechanism. LTM can be used for serving cell changes within a Master Cell Group (MCG), such as changes to the primary cell (PCell), and can also be used for serving cell changes within a secondary cell group (SCG). Cell changes using the LTM mechanism are called cell switches to distinguish them from traditional handovers. As shown in Figure 1, the network sends the LTM candidate cell configuration to the UE in advance via RRC signaling (e.g., an RRC reconfiguration message). After receiving the configuration, the UE saves the received LTM candidate cell configuration. The candidate cell configuration includes the RRC configuration corresponding to one or more candidate cells (e.g., an RRC reconfiguration message containing synchronization reconfiguration information elements). Based on the Layer 1 measurement results reported by the UE, the network determines the final target cell and triggers the cell switch process via MAC signaling (e.g., a MAC control element (CE)). The MAC signaling used to trigger the cell switch process contains at least information indicating the target candidate cell configuration (such as the corresponding candidate (configuration) identifier or index value). The UE triggers the cell switch process, starts timer T304, and applies the saved, previously received LTM candidate cell configuration to execute the target cell change process. If the T304 timer expires, the UE considers the LTM cell change process to have failed.

[0035] The LTM mechanism also supports link recovery based on LTM configuration. When a UE experiences a link failure (such as RLF, HOF, or LTM cell change failure (synchronous reconfiguration failure)), the UE initiates an RRC re-establishment process. During the cell selection process in this process (while timer T311 is running), if the UE is enabled for link recovery based on LTM configuration (i.e., the attemptLTM-Switch information element is configured), and if the cell A selected during the cell selection process is an LTM candidate cell for an MCG, the UE executes the LTM cell change process to the selected LTM candidate cell A. If the LTM cell change process to cell A fails, the UE can repeat the above process, i.e., initiate the RRC re-establishment process again, and determine whether the cell B selected during the cell selection process is an LTM candidate cell for an MCG; if so, the UE continues to execute the LTM cell change process to the selected LTM candidate cell B. In other words, the LTM mechanism supports continuous link recovery processes based on LTM configuration. The standard does not specify how many times to execute or whether to continue executing the LTM-configured link recovery process in the event of consecutive link failures or link recovery failures. In this disclosure, the terms "LTM-configured link recovery process," "LTM-based recovery," "LTM link recovery," "LTM link failure recovery," and "LTM recovery" can be interchanged.

[0036] As mentioned above, the characteristics of the link recovery process based on LTM configuration make it different from the traditional link failure recovery process. For example, a continuous link recovery process based on LTM configuration can be executed. Then when the link recovery process based on LTM configuration is executed, especially when the link recovery process based on LTM configuration is executed multiple times in succession, how the UE records and reports the information corresponding to the link failure to the network becomes the problem of concern in this disclosure. Currently, 3GPP has not yet started to formulate relevant mechanisms. One feasible way is to reuse the RLF report, that is, when the cell switch fails, the UE records the information corresponding to the link failure in the RLF report, just like the traditional handover failure. Therefore, how the UE records the information corresponding to the link failure under the LTM mechanism is the problem solved by this disclosure.

[0037] Example 1

[0038] This embodiment provides a link failure reporting method. A UE that has executed a link recovery process based on an LTM configuration includes an identifier in its link failure report for indicating the LTM link recovery cell. This allows the network to determine the cause of the link failure based on the identifier, such as a late handover or a handover to an incorrect cell.

[0039] The following describes in detail the link failure reporting method in embodiment 1. Fig. 2 is a schematic flow chart showing the link failure reporting method in embodiment 1 of the present invention.

[0040] Step 101: The UE initiates an RRC re-establishment process.

[0041] During this process, the UE starts the timer T311 and performs the cell selection process.

[0042] Optionally, when an MCG failure occurs, such as RLF of the MCG, synchronization reconfiguration failure of the MCG, or mobility failure from the NR, the UE initiates the RRC re-establishment procedure.

[0043] Optionally, the timer T311 is used to monitor the cell selection process. When the UE selects a suitable cell, the timer T311 is stopped; when T311 times out, the UE considers that the RRC re-establishment process has failed and executes the operation of entering the RRC idle state.

[0044] Step 102: If the RRC re-establishment process or the cell selection process is triggered by RLF of the MCG or synchronization reconfiguration failure of the MCG or mobility failure from the NR, if the UE is enabled with the link recovery function based on the LTM configuration, and if the selected cell is an LTM candidate cell of the MCG, the UE executes the LTM cell change execution process to the selected cell (operation 1) and includes the link recovery related information based on the LTM configuration in the link failure report (operation 2). Preferably, the link recovery related information based on the LTM configuration is information of the selected LTM candidate cell.

[0045] Furthermore, the link recovery related information configured by the LTM is the cell identifier of the selected cell (e.g., LTM cell identifier, LTM link recovery cell identifier, LTM recovery cell identifier, etc., which names are not limited in this disclosure). If the global cell identifier of the selected cell is available, the cell identifier is the global cell identifier; otherwise (if the global cell identifier is not available), the cell identifier is the physical cell identifier and carrier frequency. In this implementation, the UE sets a field in the link failure report to include the above-mentioned cell identifier, and the field is used to indicate the LTM candidate cell selected by the UE for LTM-based link recovery when timer T311 runs.

[0046] When the UE continuously performs multiple LTM-based link recovery processes, that is, the UE performs multiple cell selection processes in the RRC re-establishment process, there are multiple selected LTM candidate cells. At this time, the UE determines which cell identifier in the field in the above-mentioned link failure report is the cell identifier of which or which selected LTM candidate cells. Several implementation methods are given below.

[0047] In one implementation, the UE sets the field in operation 2 as follows: the UE includes a new LTM cell identity in the LTM cell identity list in the link failure report and sets it as the cell identity of the currently selected cell. In this implementation, the LTM cell identity list includes one or more LTM cell identity, each of which corresponds to the cell identity of an LTM candidate cell selected when T311 is executed. When the UE performs multiple LTM-based link recovery procedures consecutively, the multiple LTM cell identities in the list are recorded in the order in which the corresponding LTM-based link recovery procedures were executed. For example, if the cell selected by the UE in the first LTM-based link recovery procedure after a link failure is cell A, the UE records LTM cell identity A in the list, such as {Cell identity A}. If the LTM cell change procedure to cell A fails, and the cell selected by the UE in the second LTM-based link recovery procedure is cell B, the UE records LTM cell identity B in the list, such as {Cell identity A, Cell identity B}. Then, after the LTM cell change process to cell B fails, the cell selected by the UE in the subsequent third LTM-based link recovery process is cell C, and the UE records the LTM cell identity C in the list, such as {Cell identity A, Cell identity B, Cell identity C}. Then, the LTM cell change process to cell C succeeds, and the connection with the network side is restored. In this example, the list records the cell identities of the cells selected by the UE in the LTM-based link recovery processes that have been successively executed in chronological order. Optionally, the first item in the list corresponds to the LTM candidate cell selected in the first cell selection process after the link failure. Optionally, the first item in the list corresponds to the LTM candidate cell selected in the last / most recent cell selection process after the link failure.

[0048] In another implementation, the LTM cell identifier in the UE's link failure report always records the cell identifier of the cell selected during the first LTM-configured link recovery process performed after a link failure. More specifically, in operation 2, the UE sets the field as follows: the UE sets the field in the link failure report to the cell identifier of the LTM candidate cell selected during the first LTM-configured link recovery process performed by the UE after a link failure. That is, if this is the first LTM-based link recovery process performed by the UE after a link failure, the field in the link failure report is set to the cell identifier of the selected LTM candidate cell. Optionally, the link failure refers to a link failure event experienced / corresponding to the cell indicated by the failed cell identifier in the link failure report (such as the failedPCellId in the RLF report). In this implementation, operation 2 of step 102 can be described as follows: if the LTM cell identifier in the link failure report has not been set after a link failure is detected, then the LTM cell identifier is set to the cell identifier of the selected cell. Or if the selected cell is the first cell selected in the cell selection process after detecting the link failure, then the LTM cell identifier is set to the cell identifier of the selected cell. Or if the selected cell is the first LTM candidate cell selected after detecting the link failure (cell selection process), then the LTM cell identifier is set to the cell identifier of the selected cell.

[0049] In yet another implementation, the LTM cell identifier in the UE's link failure report always records the cell identifier of the cell selected during the last LTM-configured link recovery process performed after a link failure. More specifically, in operation 2, the UE sets the field as follows: if the LTM cell identifier in the link failure report (after detecting the link failure) has not been set, then the LTM cell identifier is set to the cell identifier of the selected cell; otherwise, the LTM cell identifier in the link failure report is replaced with the cell identifier of the selected cell. This can also be described as: if the LTM cell identifier exists in the link failure report, then the LTM cell identifier in the link failure report is replaced with the cell identifier of the selected cell; otherwise, the LTM cell identifier in the link failure report is set to the cell identifier of the selected cell. This can also be described as: setting the LTM cell identifier in the link failure report to the cell identifier of the selected cell. Optionally, prior to this, operation 2 also includes: clearing the LTM cell identifier field in the link failure report.

[0050] Optionally, the order of the UE including the link recovery related information based on the LTM configuration in the link failure report (operation 2) and the UE executing the LTM cell change execution process to the selected cell (operation 1) is not limited.

[0051] Optionally, the LTM-based link recovery function is enabled and the attemptLTM-Switch information element is configured. This information element is used to indicate that the UE should perform an LTM cell change when the selected cell is an LTM candidate cell.

[0052] Optionally, the selected cell is an LTM candidate cell of an MCG, which means that the selected cell is one of one or more LTM candidate cells in an ltm-Config associated with the MCG. The ltm-Config is used to store the LTM candidate configuration. The selected LTM candidate cell configuration is included in the LTM-Candidate information element in the ltm-Config.

[0053] Optionally, this embodiment does not limit when the UE performs the above-mentioned operation 2. In addition to step 102, the UE performs operation 2 when the cell selected during the RRC re-establishment process is an LTM candidate cell of an MCG; operation 2 can also be performed during the execution of operation 1, that is, during the LTM cell change process; operation 2 can also be performed after operation 1 is completed, such as when the LTM cell change execution process is successfully completed or failed. Optionally, the successful completion of the LTM cell change execution process refers to the successful completion of the random access process triggered by the LTM cell change; the failed completion of the LTM cell change execution process refers to the expiration of the associated timer T304.

[0054] Optionally, when the UE supports link failure reporting for LTM, the UE performs the above operation 2.

[0055] Optionally, the link failure report is an RLF report or a UE variable VarRLF-Report. In the present disclosure, no distinction is made between the RLF report and the variable VarRLF-Report.

[0056] Optionally, if the UE performs a link recovery process based on conditional reconfiguration (conditional handover-based recovery) after a link failure, the UE does not perform operation 2 or does not include the LTM cell identifier in the link failure report. Otherwise, the UE performs operation 2 or includes the field of the LTM cell identifier in the link failure report. Optionally, the execution of the link recovery process based on conditional reconfiguration may be that the link failure report includes / sets the conditional reconfiguration cell identifier (such as the choCellId information element in the RLF report). The choCellId information element is used to indicate the conditional handover candidate target cell selected by the UE for conditional handover-based recovery when timer T311 runs.

[0057] Optionally, the LTM cell identifier (ie, the field in the aforementioned operation 2) reuses the choCellId information element.

[0058] Example 2

[0059] This embodiment provides a link failure reporting method. When a UE restores its connection with the network by performing an RRC establishment procedure, the UE sets the time parameter in the link failure report based on whether the UE performed a link recovery procedure based on an LTM configuration after a link failure prior to the RRC establishment procedure. Through the method described in this embodiment, the network side can know whether the UE performed a link recovery procedure based on an LTM configuration between the execution of the RRC establishment procedure and the link failure, as well as the time information, and accordingly determine whether the RRC connection establishment procedure is for link recovery or general-purpose initial access.

[0060] The following describes in detail the link failure reporting method in embodiment 2. FIG3 is a schematic flow chart showing the link failure reporting method in embodiment 2 of the present invention.

[0061] Step 201: The UE initiates an RRC establishment process and sends an RRC establishment request message.

[0062] Step 202: When the UE receives the RRC setup message in response to the RRC setup request, if the UE link failure report contains stored link failure information, the UE performs one or more of the following operations to set the information in the link failure report:

[0063] Operation 1: If the UE supports link failure reporting for LTM and the LTM cell identifier field is set in the link failure report, the UE sets the first time information field in the link failure report to the time elapsed from the link failure experienced / corresponding to the cell indicated by the failed cell identifier in the link failure report (such as failedPCellId in the RLF report) (until the RRC establishment message is received); otherwise, the first time information field is set to the time elapsed since the last link failure. The above "otherwise, setting the first time information field to the time elapsed since the last link failure" is an optional operation.

[0064] Optionally, the condition for the UE to set the first time information field also includes: the first time information field in the link failure report is not set after the RRC re-establishment process fails and the RRC establishment message is the first RRC establishment message received by the UE since the UE declared the link failure.

[0065] Optionally, the condition for the UE to set the first time information field also includes: when the reconnection cell identification field in the link failure report after the failure of the RRC re-establishment process is not set and the RRC establishment message is the first RRC establishment message received by the UE since the UE declared the link failure. Optionally, the reconnection cell identification field is a reconnectCellId information element. The reconnectCellId information element field is used to indicate the cell to which the UE returns to the connected state (a new connection established with the network) after the connection failure and the failure to perform RRC re-establishment.

[0066] Operation 2: If the UE supports link failure reporting for LTM and the link failure report contains multiple LTM cell identifiers (or the LTM cell identifier list contains multiple (e.g., more than one) LTM cell identifiers), then the UE sets an indication information in the link failure report to indicate that the UE has performed multiple link recovery procedures based on LTM configuration after the link failure.

[0067] Optionally, the link failure report includes multiple LTM cell identifiers, which may also mean that the UE executes multiple link recovery processes based on LTM configuration after the link failure.

[0068] Optionally, the link failure in the “after link failure” refers to the link failure experienced / corresponding to the cell indicated by the failed cell identifier in the link failure report (such as failedPCellId in the RLF report).

[0069] Optionally, the condition for executing operation 2 further includes that the UE sets the first time information field in the link failure report. Optionally, the UE executes operation 2 based on executing operation 1.

[0070] Operation 3: Set the second time information field to the time elapsed from the link failure to the last / last time the UE initiated the RRC re-establishment procedure.

[0071] Optionally, the link failure in the “link failure start” refers to the link failure experienced / corresponding to the cell indicated by the failed cell identifier in the link failure report (such as failedPCellId in the RLF report).

[0072] Optionally, the last RRC re-establishment process initiated refers to the RRC re-establishment process initiated by the UE most recently before executing the RRC establishment process in step 201, which may also be referred to as a failed RRC re-establishment process.

[0073] Optionally, the execution conditions of operation 3 also include: the UE supports link failure reporting for LTM, the link failure report contains the aforementioned LTM cell identifier, and the UE executes one or more link recovery processes based on LTM configuration after the link failure.

[0074] Operation 4: Set the third time information field to the time elapsed from the link failure to the UE's most recent / last RRC re-establishment procedure failure.

[0075] Optionally, the failure of the RRC re-establishment process refers to the timer T301 used to monitor the RRC re-establishment process timing out, or the cell selected in the cell selection process is no longer suitable according to the cell selection criteria, etc.

[0076] Optionally, the failure of the most recent / last RRC re-establishment procedure may also be referred to as a failed RRC re-establishment procedure.

[0077] Optionally, the LTM cell identifier field refers to the cell identifier of the LTM candidate cell selected when the UE performs RRC connection process cell reselection in the link recovery process based on LTM configuration, as described in Example 1. Optionally, the LTM cell identifier field may include one LTM cell identifier or multiple LTM cell identifiers.

[0078] Optionally, the link failure report is an RLF report or a UE variable VarRLF-Report. In the present disclosure, no distinction is made between the RLF report and the variable VarRLF-Report.

[0079] Unless otherwise specified, the present disclosure does not limit the order of the multiple operations performed by the UE.

[0080] Example 3

[0081] This embodiment provides a method for reporting a link failure report executed on a UE. Using the method described in this embodiment, the UE can report LTM-related information in a link failure report to the base station, providing the network with more accurate failure information. This embodiment also provides a method for the signaling process when the UE reports the failure report described in the previous embodiment through the RRC process.

[0082] FIG4 is a schematic flow chart showing a link failure reporting method in Embodiment 3 of the present disclosure. As shown in FIG4 , the link failure reporting method in Embodiment 3 of the present disclosure may include the following steps.

[0083] Step 301: The UE receives a UE Information Request message from the network side, which carries an instruction / request for requesting the UE to report a stored link failure report.

[0084] Step 302: The UE includes the content of the stored link failure report in a UE Information Response message and sends the UE Information Response message to the network side. The failure report included in the UE Information Response message includes at least one or more combinations of the LTM related information in Embodiment 1 or Embodiment 2 of this document.

[0085] In the above embodiments, the name of the failure report is not limited. Optionally, the link failure report is a link failure report (RLF report). Optionally, the failure report can also be defined specifically for reporting LTM cell switch failure information. In the above embodiments, unless otherwise specified, if the UE performs multiple operations in a single step, the order in which the operations are performed is not limited.

[0086] FIG5 is a block diagram of a user device 10 according to an embodiment of the present disclosure. As shown in FIG5 , the user device 10 includes a processor 101 and a memory 102. The processor 101 may include, for example, a microprocessor, a microcontroller, an embedded processor, etc. The memory 102 may include, for example, a volatile memory (such as a random access memory (RAM)), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other memory. The memory 102 stores program instructions. When executed by the processor 101, the instructions may execute the link failure reporting method in the user device described in detail in the present disclosure.

[0087] The program running on the device according to the present disclosure may be a program that controls a central processing unit (CPU) to enable a computer to implement the functions of the embodiments of the present disclosure. The program or the information processed by the program may be temporarily stored in a volatile memory (such as a random access memory RAM), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other memory systems.

[0088] The program for realizing each embodiment function of the present disclosure can be recorded on a computer-readable recording medium. The corresponding function can be realized by making a computer system read the program recorded on the recording medium and executing these programs. The so-called "computer system" herein can be a computer system embedded in the device, and can include an operating system or hardware (such as a peripheral device). "Computer-readable recording medium" can be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a short-term dynamic storage program recording medium or any other recording medium that is computer-readable.

[0089] The various features or functional modules of the devices used in the above embodiments can be implemented or executed by circuits (e.g., single-chip or multi-chip integrated circuits). The circuits designed to perform the functions described in this specification may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of the above devices. The general-purpose processor may be a microprocessor, or any existing processor, controller, microcontroller, or state machine. The above circuits may be digital circuits or analog circuits. In the case where new integrated circuit technologies have emerged to replace existing integrated circuits due to advances in semiconductor technology, one or more embodiments of the present disclosure may also be implemented using these new integrated circuit technologies.

[0090] Furthermore, the present disclosure is not limited to the above-described embodiments. Although various examples of the embodiments have been described, the present disclosure is not limited thereto. Fixed or non-mobile electronic devices installed indoors or outdoors can be used as terminal devices or communication devices, such as AV equipment, kitchen equipment, cleaning equipment, air conditioners, office equipment, vending machines, and other household appliances.

[0091] As described above, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. However, the specific structure is not limited to the above-mentioned embodiments, and the present disclosure also includes any design changes that do not deviate from the main purpose of the present disclosure. In addition, various modifications can be made to the present disclosure within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. In addition, components with the same effect described in the above-mentioned embodiments can be replaced with each other.

Claims

1. A link failure reporting method, comprising: The user equipment UE detects a link failure and initiates the radio resource control RRC re-establishment process. Perform cell selection during RRC re-establishment. When the following conditions are met: the RRC re-establishment process is triggered by a radio link failure of a master cell group (MCG) or a synchronization reconfiguration failure of an MCG or a mobility failure from a next generation wireless system (NR); the UE is enabled with a link recovery function based on LTM configuration; the cell selected in the cell selection process is a mobility LTM candidate cell for layer 1 and layer 2 triggering of an MCG; The UE executes the LTM cell switch execution process to the selected cell, The UE includes information of the selected LTM candidate cell in the link failure report.

2. The link failure reporting method according to claim 1, wherein: The information of the selected LTM candidate cell is an LTM cell identifier, and the UE sets a field in the link failure report to include the LTM cell identifier; If the global cell identifier is valid, the LTM cell identifier is set to the global cell identifier; otherwise, the cell identifier is set to the physical cell identifier and carrier frequency.

3. The link failure reporting method according to claim 2, wherein: The setting of the LTM cell identifier is to include a new LTM cell identifier in an LTM cell identifier list.

4. The link failure reporting method according to claim 1 or 2, wherein: When the selected cell is the cell selected in the first cell selection process after link failure is detected, the LTM cell identifier is set as the cell identifier of the selected cell.

5. The link failure reporting method according to claim 1 or 2, wherein: When the LTM cell identifier in the link failure report has not been set, the LTM cell identifier is set to the cell identifier of the selected cell; otherwise, the set LTM cell identifier in the link failure report is replaced with the cell identifier of the selected cell.

6. The link failure reporting method according to claim 1, wherein: The link recovery function enabled based on LTM configuration is configured with the attemptLTM-Switch information element; the attemptLTM-Switch information element is used to indicate that the UE should perform an LTM cell change when the selected cell is an LTM candidate cell.

7. The link failure reporting method according to claim 1, wherein: The selected cell being an LTM candidate cell of an MCG means that the selected cell is one of one or more LTM candidate cells in the LTM configuration associated with the MCG.

8. The link failure reporting method according to claim 1, wherein: When the UE supports link failure reporting for LTM, the UE includes information of the selected LTM candidate cell in the link failure report.

9. A user equipment (UE), comprising: processor; as well as a memory storing instructions; The instructions, when executed by the processor, execute the link failure reporting method according to any one of claims 1 to 8.

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