WO2025031320A1 - Method for reporting link failure, and user equipment - Google Patents

Abstract

The present disclosure provides a method for reporting a link failure, and a user equipment (UE). The method for reporting a link failure comprises: a UE executes a layer 1/layer 2 triggered mobility (LTM) cell switch process; and the UE determines that the cell switch process fails; and the UE saves LTM-related failure information in a failure report, wherein the LTM-related failure information comprises one or more pieces of the following information: failure information for indicating that the failure is a failure of cell switch execution, and random access (RA) information for indicating whether RA is executed in the process of cell switch execution.

Description

Link failure reporting method and user equipment Technical Field

The present disclosure relates to the technical field of wireless communications, and more specifically, to a link failure reporting method and a corresponding user equipment.

Background Art

In wireless networks, network performance can be optimized through network optimization. Generally, data collection and data analysis are performed on the existing deployed and running networks to find out the reasons affecting network quality, and network performance is improved by modifying the configured network parameters, adjusting the network structure and deployed equipment. Self-configuration and Self-Optimization Network (SON) refers to the process of automatically adjusting the network based on the measurement/performance measurement of user equipment and/or base stations. The network side can configure the UE to perform measurements for SON. SON functions include many aspects, such as the Automatic Neighbor Relation Function (ANR) to reduce the neighbor management burden of operators, the Mobility Load Balancing (MLB) to balance the load between different cells, the Mobility Robustness Optimization (MRO) to optimize mobility performance, the Random Access Channel Optimization function to optimize random access channel parameters, and the Radio Link Failure Reporting function to optimize coverage and MRO.

In addition, Minimization of Drive Tests (MDT) technology is also an important means for operators to optimize their networks. Through the drive test data obtained from the UE, the relevant parameters for network optimization are obtained, and based on the analysis of these data, the status of network deployment and operation is obtained, so as to decide how to improve the operation status of the network. The main application scenarios of MDT are coverage optimization, capacity optimization, mobility management optimization, QoS parameter optimization, and public channel parameter configuration optimization.

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

The introduction of the Layer 1/L2-triggered mobility (LTM) mechanism is being discussed in the NR system of Release 18. The purpose of this mechanism is to reduce the mobility delay. In NR systems before 18, mobility is mainly achieved through handover (also called 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, then adds the target service cell, and needs to perform a complete layer 2 and layer 1 reset operation. This results in longer latency, higher overhead, and longer data interruption time in the mobility process. 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 reducing latency, overhead, and interruption time.

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

The main purpose of the present disclosure is to provide a link failure reporting method and a user device, so as to realize the reporting of failure information related to LTM cell switch in a system supporting LTM and the setting problem of failure information when realizing failure information reporting in the LTM scenario.

According to a first aspect of the present disclosure, a link failure reporting method is provided, comprising: a user equipment UE executes a cell switch process for triggering LTM cell change of layer 1 and layer 2 mobility; the UE determines that the cell switch process fails; and the UE saves LTM related failure information in a failure report, wherein the saving of LTM related failure information includes one or more of the following operations: Operation 1: including first failure information. The first failure information is used to indicate that the failure is a failure of LTM cell switch execution. Operation 2: if the layer 1 or layer 2 signaling used to trigger the cell switch process does not include valid TA information, then including second failure information for indicating random access information. Operation 3: if a random access process is triggered during the LTM cell switch execution process, then including second failure information for indicating random access information. Operation 4: including third failure information for indicating that the link failure is a failure of the LTM cell switch process in which the random access process is executed. Operation 5: setting fourth failure information for indicating that the link failure is a failure of the RACH-less cell switch process in which random access is not executed. Operation 6: Contains fifth failure information for indicating layer 1 measurement results of a source cell or a target cell or one or more neighbor cells related to a cell switch.

In the link failure reporting method of the first aspect, the UE determines that the cell switch process fails based on the expiration of the LTM cell switch timer; the timer is an indication received by the radio resource control RRC layer from the bottom layer to indicate that the LTM cell switch process is triggered. Start at .

In the link failure reporting method of the first aspect above, the layer 1 or layer 2 signaling does not contain valid information, which means that the signaling does not contain time advance information; or the time advance indication information uses a zero value or the same time advance as a certain serving cell; or it means that the time advance information contained in the command for triggering the cell switch does not set a special value.

In the link failure reporting method of the first aspect above, the first failure information or the third failure information is identified by a connection failure type connectionFailureType information element; and the second failure information is identified by a ra-InformationCommon information element.

In the link failure reporting method of the first aspect, operation 2 is performed only when operation 1 is performed.

In the link failure reporting method of the first aspect above, operation 4 is performed only if the layer 1 or layer 2 signaling does not include valid TA information.

In the link failure reporting method of the first aspect mentioned above, the layer 1 or layer 2 signaling is LTMCell Switch Command media intervention control MAC control element CE.

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.

Effects of the Invention

According to the link failure reporting method and user equipment performed by the user equipment disclosed in the present invention, it is expected that in a system supporting LTM, it is possible to implement the reporting of LTM-specific performance information when reporting a link failure and to implement the setting of random access information when reporting a link failure in an LTM scenario, so that the network side can distinguish whether the link failure is due to a failure caused in the LTM process and obtain the random access information corresponding to the random access process initiated to the target base station in the LTM process, and based on the information, analyze the random access performance and LTM configuration in the LTM scenario and optimize the parameter configuration in a more refined manner.

BRIEF DESCRIPTION OF THE DRAWINGS

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:

Figure 1 is a schematic flow chart showing the cell switching process based on the LTM mechanism.

FIG. 2 is a schematic flow chart showing a link failure reporting method in Embodiment 1 of the present invention.

FIG. 3 is a schematic flow chart showing a link failure reporting method in Embodiment 2 of the present invention.

FIG. 4 is a schematic flow chart showing a link failure reporting method in Embodiment 3 of the present invention.

FIG5 is a schematic flow chart showing a link failure reporting method in Embodiment 5 of the present invention.

FIG6 shows a block diagram of a user equipment according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

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.

In this specification, the various embodiments described below for describing the principles of the present disclosure are merely illustrative and should not be interpreted in any way as limiting the scope of the disclosure. The following description with reference to the accompanying drawings is used to help fully understand 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 are omitted. In addition, throughout the accompanying drawings, the same reference numerals are used for similar functions and operations.

In the present disclosure, the terms "include" and "contain" and their derivatives are intended to include but not be limited; the term "or" is inclusive, meaning and/or. "If", "if", "in the case of" and "when" are interchangeable.

The following takes the NR mobile communication system as an example application environment to specifically describe multiple implementations according to the present disclosure. However, it should be noted that the present disclosure is not limited to the following implementations, but can be applied to more other wireless communication systems, such as an LTE system connected to a 5G core network.

The base station in the present disclosure can be any type of base station, including Node B, enhanced base station eNB, 5G communication system base station gNB; or micro base station, pico base station, macro base station, home base station, etc.; the network side generally refers to a base station or a cell. The cell can also be a cell under any type of base station mentioned above. If there is no special explanation, the cell, beam, and transmission point (Transmission Point, TRP) can be interchangeable. The base station can also be a central unit (gNB-Central Unit, gNB-CU) or a distributed unit (gNB-Distributed Unit, gNB-DU) that constitutes the base station. Between different embodiments The work may also be combined, for example, the same variables/parameters/nouns in different embodiments may be interpreted the same. Cancel, release, delete, clear and clear may be replaced. Execute, use and apply may be replaced. Configure and reconfigure may be replaced. Monitor and detect may be replaced. Initiate and trigger may be replaced.

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

Random Access Channel: Random Access Channel, RACH. Refers to the channel used to send random access preambles. In the present disclosure, RACH can refer to both the transmission channel RACH and the physical random access channel (PRACH), without distinction. RACH parameters/configuration refer to the wireless configuration for implementing the random access function, including PRACH related configurations, such as the maximum number of preamble transmissions, power boost parameters, random access response receiving window size, medium access control (MAC) contention resolution timer configuration, PRACH resource configuration, message 1 (i.e. preamble) subcarrier spacing, information used to indicate the number of synchronization channel blocks (SSBs) corresponding to each RACH occasion (RO) and the number of contention-based random preambles corresponding to each SSB, backoff parameters (in the scalingFactorBI information element), etc. PRACH resources can refer to physical frequency resources, time domain resources, or code domain resources (such as preamble) used for random access.

Random access RA process:

UE can trigger the random access process in various situations, such as initial access, beam recovery request, cell switching, uplink asynchronization, no available Physical Uplink Control Channel (PUCCH) resources, etc.

In the existing NR mechanism, the random access process can be divided into contention-based random access (Contention Based Random Access, CBRA) and non-contention-based random access (i.e., contention-free random access (Contention Free Random Access, CFRA)). The CBRA process includes four steps: the first step is for the UE to send message 1 (i.e., random access preamble) to the base station; the second step: the UE receives message 2 from the base station (i.e., random access response Random Access Response, RAR); the third step: the UE sends message 3 (uplink transmission scheduled by the uplink grant in message 2), which is generally used to send UE identification to the base station, RRC messages for radio resource control (RRC) connection establishment/recovery/reestablishment, and random access. UE contention resolution identifier for entering contention resolution, etc.; Step 4: UE receives message 4 from the base station (i.e., the message used for contention resolution). The PRACH resources used in CBRA are shared by many UEs. When the UE completes the above four steps of random access of CBRA and the contention is resolved successfully, the random access process is successfully completed. The CFRA process includes two steps: Step 1: UE uses the dedicated PRACH resources acquired in advance to send a preamble to the base station; Step 2: UE receives RAR from the base station. After successfully receiving message 2 associated with message 1, the UE considers that the CFRA process is successfully completed. In addition, a two-step random access process, including message A and message B, is introduced in version 16 and later NRs.

In the present disclosure, RA process and RACH process can be replaced. RA information and RACH information can be replaced.

Radio link failure reporting mechanism in the existing mechanism:

In the NR system, the UE will generate and save a radio link failure report (RLF Report) when a radio link failure (RLF) or a handover failure (HOF) occurs, and save the radio link failure information in the UE variable VarRLF-Report. In general, 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 radio link failure report (the rlf-Report information element in the UE information response UEInformationResponse message) to the network side in the response RRC message. The wireless link failure report obtained by the network side is used for network optimization, such as network coverage and mobility robustness optimization. The wireless link failure report contains information related to the link failure, including the source cell, target cell or neighbor cell identification and measurement results, 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 time the UE enters the RRC connection state after the connection failure and the failure of the re-establishment process (recorded as timeUntilReconnection information element), RRC re-establishment cell identity, random access process information performed before link failure, etc. RLF and HOF are collectively referred to as connection failure. The random access process information contained in the RLF report refers to the random access common information, including the reference downlink frequency information associated with the random access process (such as the absolute frequency of Point A, subcarrier spacing, bandwidth location information locationAndBandwidth, etc.) and the RA information associated with each random access attempt arranged in chronological order. The RA information associated with each random access attempt includes the beam index value, the number of consecutive random access attempts on the beam (that is, the number of consecutive random access preambles corresponding to the beam), whether random access contention is detected, whether the reference signal received strength (RSRP) of the beam corresponding to the random access resource used by the random access attempt is higher than a configured threshold value, the fallback information of the two-step random access process to the four-step random access process, and the downlink quality measured by the UE before the two-step random access process is triggered.

LTM Mechanism:

Traditional handover triggers handover through layer 3 handover command (i.e., RRC reconfiguration message containing synchronous reconfiguration information element). In order to reduce data interruption caused by mobility, the 3GPP working group is currently discussing and specifying the LTM mechanism. In the conclusions reached so far, LTM can be used for service cell changes in the Master Cell Group (MCG), such as changes in the Primary Cell (PCell), and can also be used for service cell changes in the Secondary Cell Group (SCG). Cell change using the LTM mechanism is called cell switch to distinguish it from traditional handover. As shown in Figure 1, the network side sends the LTM candidate cell configuration to the UE in advance through RRC signaling (such as RRC reconfiguration message). After receiving the configuration, the UE saves the received LTM candidate cell configuration. The candidate cell configuration includes one or more RRC configurations corresponding to candidate cells. The network side determines the final target cell based on the layer 1 measurement results reported by the UE, and triggers the cell switch process through MAC signaling (such as MAC control element (CE)). The MAC signaling used to trigger the cell switch process contains at least the indication information of the target candidate cell configuration (such as the corresponding candidate (configuration) identifier or index value). The UE triggers the cell switch process and applies the saved previously received LTM candidate cell configuration to execute the change process to the target cell. In addition, the configuration of the LTM candidate cell does not reuse the current handover command structure, that is, it does not use the synchronous reconfiguration information element. RRC reconfiguration message.

In the LTM mechanism, in order to further reduce the delay of the cell change process, the network side can obtain the uplink timing advance (TA) of the candidate cell in advance before triggering the cell change, so that when the UE subsequently performs the cell switch process to the target cell, the random access process to the target cell can be omitted, and the acquired uplink TA value can be directly used for uplink transmission. This method is called early TA acquisition in this disclosure. The UE performs early TA acquisition for a candidate cell based on the indication/configuration of the network side, that is, performs a random access process on the candidate cell to obtain the TA of the candidate cell, as shown in Figure 1. The network side can configure dedicated random access resources to the UE through a physical downlink control channel order (PDCCH order) to trigger a random access process to a candidate cell. In the corresponding random access process, the UE only needs to send a random access preamble to the candidate cell to end the RA process. If the random access preamble sent by the UE is not successfully received by the network side, the network side can re-trigger the UE to resend the random access preamble through the PDCCH order. The network side records the corresponding TA obtained and includes the TA value in the MAC signaling used to trigger the cell switch to inform the UE. Therefore, unlike the traditional switching process in which the UE always needs to perform a random access process to the target cell to access the target cell and obtain uplink synchronization, in LTM, when the UE has obtained the TA of the LTM target cell in advance, the UE can directly send uplink data to the LTM target cell through dynamic scheduling or configured resources (Configured Grant, CG) without performing random access to the target cell. This cell switch process can also be called RACH-less cell switch or cell switch without RA. Similarly, the process of performing a random access process to obtain uplink synchronization during the cell switch process without performing advance TA acquisition can be called cell switch with RA or RACH-based cell switch.

In the current NR system, when a handover fails or a radio link fails, the UE generates an RLF report to record relevant failure information, which includes random access related information. In the existing mechanism, the UE determines whether to include random access related information in the RLF report (such as identified by the ra-InformationCommon information element) based on the connection failure type and radio link failure reason in the RLF report. Specifically, when the connection failure type (connectionFailureType information element) in the RLF report is RLF and the RLF reason is a random access problem (randomaccessproblem) or beam failure recovery failure (beamFailureRecoveryFailure), or when the connection failure type is HOF and the failed handover is a handover within the NR system, the UE includes random access related information in the RLF report. Access related information. As mentioned above, the characteristics of the LTM process make it different from the traditional switching process. When a cell switch fails in an LTM scenario, how does the UE record the information corresponding to the link failure? At present, 3GPP has not yet begun to formulate relevant mechanisms. One 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 switching failure. Considering the TA advance acquisition mechanism in the LTM mechanism, how to determine whether to include random access related information in the report used to record failure information (such as the RLF report) becomes a problem. In addition, unlike the traditional switching that is always based on the measurement results of Layer 3, the base station in the LTM mechanism determines whether to trigger and when to trigger the MAC command of the cell switch based on the L1 measurement results reported by the UE (such as the Channel State Information (CSI) report). Therefore, how to record the corresponding measurement results in the failure information after the LTM failure has also become a problem of concern in this disclosure.

The present disclosure mainly proposes solutions to the above-mentioned problems related to link failure reporting in the scenario supporting LTM. Through the solution described in the present disclosure, the UE carries in the link failure report whether the RA process is executed during the cell switch execution process in the LTM mechanism and information related to the executed RA process or layer 1 measurement results, so that the network side can obtain the RA-related information or layer 1 measurement results in the cell switch execution process, so that the network side can better judge the cause of the link failure or LTM execution failure or the configuration problem of random access parameters, and optimize the LTM-related mobility parameters and the corresponding dedicated random access information configuration based on this.

Example 1

This embodiment provides a link failure reporting method. The UE determines whether to include random access information in the failure report of the corresponding cell switch process based on whether the cell switch command carries a TA value. If the cell switch command corresponding to the cell switch process does not carry a TA value, the UE includes the RA information of the executed random access process in the failure report corresponding to the failure of the cell switch process.

The following is a detailed description of the link failure reporting method in Embodiment 1. Fig. 2 is a schematic flow chart showing the failure reporting method in Embodiment 1 of the present invention.

Step 101: The LTM cell switch execution process of the UE fails.

Optionally, the cell switch execution process failure refers to a fixed number associated with the cell switch process. The timer times out. The timer starts when the cell switch process starts and stops when the cell switch process ends successfully.

Optionally, the timer is started when the UE RRC layer receives an indication from the bottom layer indicating that the LTM cellswitch process is triggered. Optionally, the bottom layer refers to the MAC layer of the UE.

Optionally, the timer is configured via the LTM-Timers information element in the special cell configuration SpCellConfig.

Step 102: The UE includes failure information corresponding to the failed cell switch process in the failure report, which includes one or more of the following operations:

Operation 1: including first failure information. The first failure information is used to indicate that the failure is an LTM failure or an LTM cell switch execution failure.

Optionally, the first failure information is identified by a connection failure type (connectionFailureType).

Operation 2: If the layer 1 or layer 2 signaling used to trigger the cell switch process does not include valid TA information, second failure information is included. The second failure information is information related to the random access process.

Optionally, the layer 1 or layer 2 signaling is LTM Cell Switch Command MAC CE.

Optionally, the not containing valid information means that the command for triggering the cell switch does not contain time advance information, such as a time advance command (Timing Advance Command) or time advance indication information indicating that the time advance information uses a zero value or the same as the time advance amount of a certain serving cell; or it means that the time advance information contained in the command for triggering the cell switch does not set a special value (such as each bit of the time advance command is set to all 1 or hexadecimal FFF).

Optionally, in operation 2, if the layer 1 or layer 2 signaling used to trigger the cell switch process does not contain valid TA information, and the UE is not configured or enabled for UE-based TA measurement, a second failure information is included. The UE-based TA measurement means that a UE with such capability can autonomously complete TA measurement to the target cell without the network side indicating the TA value to it. Optionally, the network side can configure/enable UE-based TA measurement through an RRC message or an LTM cell switch command.

Optionally, the second failure information is identified by a ra-InformationCommon information element.

Optionally, operation 2 is performed when operation 1 is performed, that is, when the first failure information is set in the failure report, the UE performs operation 2.

Optionally, this embodiment further includes step 100. In step 100, the UE receives a message from the network The LTM cell switch command on the remote side is executed and the LTM cell switch execution process is performed.

Example 2

This embodiment provides a link failure reporting method. The UE determines whether to include random access information in the failure report of the corresponding cell switch process based on whether the random access process is performed during the cell switch execution process. If the random access process is performed during the cell switch execution process, the UE includes the RA information of the executed random access process in the failure report corresponding to the failure of the cell switch process.

The following is a detailed description of the link failure reporting method in Embodiment 2. Fig. 3 is a schematic flow chart showing the failure reporting method in Embodiment 2 of the present invention.

Step 201: The LTM cell switch execution process of the UE fails.

Optionally, the failure of the cell switch execution process refers to the timeout of a timer associated with the cell switch process. The timer is started when the cell switch process starts and is stopped when the cell switch process ends successfully.

Optionally, the timer is started when the UE RRC layer receives an indication from the bottom layer indicating that the LTM cell switch process is triggered. Optionally, the bottom layer refers to the MAC layer of the UE.

Optionally, the timer is configured via the LTM-Timers information element in the special cell configuration SpCellConfig.

Step 202: The UE includes failure information corresponding to the failed cell switch process in the failure report, which includes one or more of the following operations:

Operation 1: including first failure information. The first failure information is used to indicate that the failure is an LTM failure or an LTM cell switch execution failure.

Optionally, the first failure information is identified by a connection failure type (connectionFailureType).

Operation 2: If the UE triggers or executes a random access process during the LTM cell switch execution process, the second failure information is included. The second failure information is information related to the random access process.

Optionally, the layer 1 or layer 2 signaling is LTM Cell Switch Command MAC CE.

Optionally, the random access procedure is performed during the LTM cell switch execution process, which means that a random access procedure is performed to the target cell of the cell switch. It can also be stated that during the operation of the LTM cell switch timer in step 201 (the timer associated with the failed cell switch process), the UE performs a random access procedure.

Optionally, the second failure information is identified by a ra-InformationCommon information element.

Optionally, operation 2 is performed when operation 1 is performed, that is, when the first failure information is set in the failure report, the UE performs operation 2.

Optionally, the embodiment further includes step 200. In step 200, the UE receives an LTM cell switch command from the network side and executes an LTM cell switch execution process.

In the above embodiments, the difference between Embodiment 2 and Embodiment 1 is that Embodiment 2 considers the random access process triggered by other reasons during the cell switch process, such as the random access triggered by Beam Failure Recovery (BFR). In Embodiment 1, only the random access process triggered by obtaining uplink synchronization with the target cell (i.e., obtaining the TA advance of the target cell) during the cell switch process is considered. Therefore, when the UE does not obtain a valid TA value from the LTM cell switch command, the UE needs to obtain the TA through the random access process to the target cell. Therefore, the UE includes the random access information related to the random access process for obtaining the TA for uplink synchronization in the failure report corresponding to the cell switch, so as to be used by the network side to analyze and adjust the link failure. In Embodiment 2, in addition to the random access to the target cell triggered by obtaining the TA/uplink synchronization, during the execution of the cell switch, random access may be triggered by other reasons. For example, in the existing mechanism, the beam failure recovery mechanism (such as when the beam failure indication counter BFI_COUNTER on a special cell is greater than or equal to the configured maximum value beamFailureInstanceMaxCount, the UE performs beam failure recovery by triggering a random access process) does not specify whether the random access process can be triggered by BFR during the cell switching process. One understanding is that during the cell switching process (when T304 is running), the UE still performs beam failure detection (BFD) on the target cell, and when BFR is triggered, the UE triggers a random access process for BFR. Another understanding is that during the cell switching process, because the UE has not successfully accessed the target cell, the UE does not perform BFD on the target cell, or does not trigger a random access process because of BFR. Then it is not clear whether the LTM cell switch process executes BFD or BFR to the target cell. In one understanding, during the LTM cell siwtch process (that is, when the LTM timer is running in step 101), the UE still performs BFD or BFR on the target cell. Under this understanding, in Embodiment 2, for the random access process triggered by this situation, the UE will also include the corresponding random access information in the failure report corresponding to the cell switch failure. Optionally, the UE may further indicate in the failure report whether the random access process related to the random access information is used for uplink synchronization with the target cell, such as indicating that the random access process is performed by In another understanding, during the cell switch execution process, because the UE has not successfully accessed the target cell, the UE does not perform BFD or BFR for the target cell, or does not trigger the random access process due to BFR. In this understanding, the implementation effects of Embodiment 2 and Embodiment 1 are the same, that is, the random access information recorded in the failure report is only used for uplink synchronization to the target cell.

Example 3

This embodiment provides another link failure reporting method. The UE determines the link failure type in the failure report based on whether the cell switch command carries a TA value, and determines whether to include random access information based on the link failure type.

The following is a detailed description of the link failure reporting method in Embodiment 3. Fig. 4 is a schematic flow chart showing the failure reporting method in Embodiment 3 of the present invention.

Step 301: The LTM cell switch execution process of the UE fails.

Optionally, the failure of the cell switch execution process refers to the timeout of a timer associated with the cell switch process. The timer is started when the cell switch process starts and is stopped when the cell switch process ends successfully.

Optionally, the timer is started when the UE RRC layer receives an indication from the bottom layer indicating that the LTM cell switch process is triggered. Optionally, the bottom layer refers to the MAC layer of the UE.

Optionally, the timer is configured via the LTM-Timers information element in the special cell configuration SpCellConfig.

Step 302: The UE includes failure information corresponding to the failed cell switch process in the failure report, which includes one or more of the following operations:

Operation 1: including third failure information. The third failure information is used to indicate that the link failure is a failure of the LTM cell switch process that performs a random access process.

Optionally, the third failure information is identified by a connection failure type (connectionFailureType).

Optionally, if the layer 1 or layer 2 signaling used to trigger the cell switch process in step 301 does not include valid TA information, the third failure information is included.

Optionally, the layer 1 or layer 2 signaling is LTM Cell Switch Command MAC CE.

Optionally, the not containing valid information means that the command for triggering the cell switch does not contain time advance information, such as a time advance command or a timing advance command. The time advance indication information uses a zero value or the same time advance indication information as a time advance amount of a serving cell; or refers to that the time advance information contained in the command for triggering the cell switch does not set a special value (such as the time advance command is set to all 1s or hexadecimal FFF).

Optionally, in operation 1, if the layer 1 or layer 2 signaling used to trigger the cell switch process does not contain valid TA information, and the UE is not configured or enabled for UE-based TA measurement, a third failure information is included. The UE-based TA measurement means that a UE with such capability can autonomously complete TA measurement to the target cell without the network side indicating the TA value to it. Optionally, the network side can configure/enable UE-based TA measurement through an RRC message or an LTM cell switch command.

Operation 2: When operation 1 is performed, the UE includes/sets second failure information in the failure report. The second failure information is information related to the random access process.

Optionally, the second failure information is identified by a ra-InformationCommon information element.

Optionally, the embodiment further includes step 300. In step 300, the UE receives an LTM cell switch command from the network side and executes an LTM cell switch execution process.

In the above embodiments, the difference between Embodiment 1 and Embodiment 3 is whether the same connection failure type is set for the failure of the LTM cell switch process that does not perform the RA process (such as the uplink TA advance amount of the target cell has been obtained through the advance TA acquisition mechanism) and the LTM cell switch process that performs the RA process or whether an independent connection failure type is set for each. In Embodiment 1, whether the cell switch process is RACH-less cell switch or cell switch with RA, if a cell switch failure occurs, the UE sets the same first failure information (indicating the same connection failure type), so the UE needs to use other information to determine whether the cell switch process corresponds to random access. In Embodiment 3, if a cell switch failure occurs, the UE sets different connection failure type indication information for RACH-less cell switch and cell switch with RA, such as for the cell switch process of cell switch with RA, the UE sets the third failure information to indicate that the link failure is the failure of the LTM cell switch process that performs the random access process; for the RACH-less cell switch process, the UE sets the fourth failure information to indicate that the link failure is the failure of the RACH-less cell switch process. Therefore, in Embodiment 3, the UE can determine that RA for uplink synchronization is performed in the cell switch process through the third failure information, so the UE performs operation 2 when operation 1 is performed. Therefore, Embodiment 1 and Embodiment 3 can achieve the same effect. The network side can know whether the UE performs cell switch with RA or RACH- less cell switch and specific RA information when cell switch with RA is executed.

Example 4

This embodiment provides another link failure reporting method. In the failure report corresponding to the cell switch process, the UE includes the latest layer 1 measurement result when the link fails. Traditional switching is based on layer 3 measurement results, so generally speaking, the UE will include the layer 3 measurement result when the link fails in the traditional RLF report at RLF or HOF, so that the network side can analyze the link quality/status. In the cell switch process, unlike the traditional layer 3 switching, the network side preparation of the cell switch is still based on the layer 3 measurement results, that is, the network side determines which LTM candidate cells to configure to the UE based on the layer 3 measurement results; but the triggering of the cell switch process is based on the layer 1 measurement results, so by carrying the layer 1 measurement results in addition to the layer 3 measurement results in the failure report, the network side can connect the layer 1 measurement value when the link fails, thereby adjusting the mobility parameters of the cell switch process (cell switch trigger threshold value based on L1 measurement) to improve the success rate of the cell switch.

The link failure reporting method in Embodiment 4 is described in detail below.

Step 401: The LTM cell switch execution process of the UE fails.

Optionally, the failure of the cell switch execution process refers to the timeout of a timer associated with the cell switch process. The timer is started when the cell switch process starts and is stopped when the cell switch process ends successfully.

Optionally, the timer is started when the UE RRC layer receives an indication from the bottom layer indicating that the LTM cell switch process is triggered. Optionally, the bottom layer refers to the MAC layer of the UE.

Optionally, the timer is configured via the LTM-Timers information element in the special cell configuration SpCellConfig.

Step 402: The UE includes failure information corresponding to the failed cell switch process in the failure report, which includes one or more of the following operations:

Operation 1: including first failure information. The first failure information is used to indicate that the failure is an LTM failure or an LTM cell switch execution failure.

Optionally, the first failure information is identified by a connection failure type (connectionFailureType).

Operation 2: Including fifth failure information. The fifth failure information includes a layer 1 measurement result related to the cell switch.

Optionally, the layer 1 measurement result is the latest layer 1 measurement result collected when the UE detects a failure (up to the moment the UE detected failure).

Optionally, the layer 1 measurement result is a layer 1 measurement result of a source cell or a target cell or one or more LTM candidate cells.

Optionally, the LTM candidate cell refers to one or more other LTM candidate cells except the target cell.

Optionally, the LTM candidate cells refer to LTM candidate cells configured for all UEs.

Optionally, the LTM candidate cell refers to an LTM candidate cell included in the neighboring cell measurement result list measResultNeighCells. That is, if a neighboring cell in the neighboring cell measurement result list is an LTM candidate cell, its layer 1 measurement result is included in its measurement result.

Optionally, the layer 1 measurement result refers to a channel state information report (Channel State Information report, CSI report) or a CSI measurement report.

Optionally, the layer 1 measurement result is a layer 1 measurement result based on a synchronization signal block (SSB).

Optionally, the layer 1 measurement result is layer 1 reference signal received power (Reference Signal Received Power, RSRP).

Optionally, the embodiment further includes step 400. In step 400, the UE receives an LTM cell switch command from the network side and executes an LTM cell switch execution process.

Example 5

This embodiment provides a method for reporting a link failure report executed on a UE. Through the method described in this embodiment, the UE can report LTM related information to the base station in the failure report to provide more accurate failure information to the network side. This embodiment provides a method for the signaling process when the UE reports the failure report described in the above embodiment through the RRC process.

FIG5 is a schematic flow chart showing a link failure reporting method in Embodiment 5 of the present disclosure. As shown in FIG5 , the link failure reporting method in Embodiment 5 of the present disclosure may include the following steps.

Step 501: The UE receives a UE information request UEInformationRequest message from the network side, which carries an indication/request for requesting the UE to report a stored failure report.

Step 502: The UE includes the content of the stored failure report in a UE information response UEInformationResponse message, and sends the UEInformationResponse message to the network side. The failure report included in the UEInformationResponse message includes at least A combination of one or more of the failure information in 1 to 4 or in Example 6 (such as the first failure information to the fifth failure information).

In the above embodiments, the name of the failure report is not limited. Optionally, the failure report refers to a link failure report RLF report. Optionally, the failure report may also be defined specifically for reporting LTM cell switch failure information. In the above embodiments, if not specifically stated, if the UE performs multiple operations in one step, the execution order of the operations is not limited.

Example 6

This embodiment provides another link failure reporting method. In the failure report of the UE configured with the LTM configuration, the UE includes the latest layer 1 measurement result when the link fails. Different from Example 4, in Example 4, after the cell switch process is triggered and fails to execute, the UE includes the fifth failure information including the layer 1 measurement result in the corresponding failure report. In this embodiment, when the UE has a wireless link failure (not the case of the cell switch process execution failure), the UE includes the fifth failure information including the layer 1 measurement result in the corresponding failure report.

The failure reporting method in Example 6 is described in detail below.

Step 601: The UE detects a radio link failure (RLF).

Optionally, the UE considers that RLF is detected when one or more of the following situations occurs:

Case 1: Timer T310 for radio link failure monitoring times out;

Case 2: Timer T312 for radio link failure monitoring times out;

Case 3: A random access problem indication is received from the MAC layer and timers T300, T301, T304, T311 and T319 are not in operation; these timers are used to monitor the RRC connection establishment process, the RRC connection re-establishment process, the switching process, the cell reselection process during the RRC re-establishment process and the RRC connection recovery process.

Case 4: An indication is received from the RLC layer that the maximum number of retransmissions has been reached.

The above timers are all timers associated with the Master Cell Group (MCG).

Step 602: The UE saves the information related to the link failure in the failure report. If the UE has a saved LTM configuration or the UE is configured with the LTM configuration, the UE includes the failure information related to the failed LTM in the failure report, which includes the following operations:

Operation 1: Include the fifth failure information. The fifth failure information includes the LTM cell switch Related layer 1 measurements.

Optionally, the layer 1 measurement result is the latest layer 1 measurement result collected when the UE detects a failure (up to the moment the UE detected failure).

Optionally, the layer 1 measurement result is a layer 1 measurement result of a serving cell or one or more LTM candidate cells. The serving cell refers to a cell where RLF occurs.

Optionally, the LTM candidate cells refer to LTM candidate cells configured for all UEs.

Optionally, the LTM candidate cell refers to an LTM candidate cell included in the neighboring cell measurement result list measResultNeighCells. That is, if a neighboring cell in the neighboring cell measurement result list is an LTM candidate cell, its layer 1 measurement result is included in its measurement result.

Optionally, the layer 1 measurement result refers to a channel state information report (Channel State Information report, CSI report).

Optionally, this embodiment further includes step 600. In step 600, the UE receives LTM configuration from the network side.

FIG6 is a block diagram of a user device 10 according to an embodiment of the present disclosure. As shown in FIG6 , 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 memories, etc. Program instructions are stored on the memory 102. When the instructions are executed by the processor 101, the above-mentioned failure reporting method in the user device described in detail in the present disclosure may be executed.

The program running on the device according to the present disclosure may be a program that enables a computer to implement the functions of the embodiments of the present disclosure by controlling a central processing unit (CPU). The program or 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.

The program for realizing the functions of each embodiment of the present disclosure can be recorded on a computer-readable recording medium. The corresponding functions 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 recording medium of a short-term dynamic storage program, or any other recording medium readable by a computer.

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). Circuits designed to perform the functions described in this specification may include general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), 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.

In addition, the present disclosure is not limited to the above-mentioned 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.

As mentioned 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 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 changes can be made to the present disclosure within the scope of the claims, and the 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, the components with the same effect described in the above embodiments can be replaced by each other.

Claims (8)

A link failure reporting method, comprising: The user equipment UE executes the cell switch procedure for layer 1 and layer 2 triggered mobility LTM; The UE determines that the cell switching process fails; and The UE saves LTM related failure information in the failure report. Saving the LTM related failure information includes one or more of the following operations: Operation 1: including first failure information, where the first failure information is used to indicate that the failure is an LTM cell switch execution failure; Operation 2: if the layer 1 or layer 2 signaling used to trigger the cell switch process does not include valid TA information, then include second failure information for indicating random access information; Operation 3: if a random access process is triggered during the execution of the LTM cell switch, second failure information indicating random access information is included; Operation 4: including third failure information for indicating that the link failure is a failure of an LTM cell switch process in which a random access process is performed; Operation 5: setting fourth failure information, used to indicate that the link failure is a failure of a RACH-less cell switch process without performing random access; Operation 6: Contains fifth failure information for indicating layer 1 measurement results of a source cell or a target cell or one or more neighbor cells related to a cell switch. The link failure reporting method according to claim 1, wherein: The UE determines that the cell switch process fails based on the LTM cell switch timer timeout; The timer is started when the radio resource control RRC layer receives an indication from the lower layer indicating that the LTM cellswitch process is triggered. The link failure reporting method according to claim 1, wherein: The layer 1 or layer 2 signaling does not contain valid information, which means that the signaling does not contain time advance information; or the time advance indication information uses a zero value or a time advance indication information that is the same as the time advance amount of a certain serving cell; or it means that the time advance information contained in the command for triggering the cell switch does not set a special value. The link failure reporting method according to claim 1, wherein: The first failure information or the third failure information is a connection failure type The second failure information is identified by the connectionFailureType information element; the second failure information is identified by the ra-InformationCommon information element. The link failure reporting method according to claim 1, wherein: Operation 2 is executed only after operation 1 is executed. The link failure reporting method according to claim 1, wherein: Operation 4 is performed only if the layer 1 or layer 2 signaling does not include valid TA information. The link failure reporting method according to claim 1, wherein: The layer 1 or layer 2 signaling is LTM Cell Switch Command media intervention control MAC control element CE. A user equipment UE, comprising: Processor; and A memory storing instructions; Wherein, when the instructions are executed by the processor, the link failure reporting method according to any one of claims 1 to 7 is executed.