Radio link recovery method and user equipment

Abstract

The present disclosure provides a radio link recovery method and user equipment. A radio link recovery method comprises: receiving, by User Equipment (UE), a Conditional HandOver (CHO) configuration from a network side; initiating a Radio Link Control (RRC) reestablishment process, and performing cell selection; when a selected suitable cell is a CHO candidate cell comprising a CHO configuration for adding and changing a CPAC configuration of a conditional primary secondary cell, if an execution condition of a CPAC candidate cell in the CPAC configuration is met, performing link recovery by using the CHO configuration comprising the CPAC configuration corresponding to the CPAC candidate cell; and if the execution condition is not met, performing link recovery by using the CHO configuration comprising the CPAC configuration corresponding to the CPAC candidate cell having a best signal quality.

Description

Wireless link recovery method and user equipment Technical Field

[0001] The present disclosure relates to the technical field of wireless communications, and more particularly, to a radio link recovery method executed in a conditional cell change process and a corresponding user equipment. Background Art

[0002] The 3GPP RAN working group is currently conducting a research project for Release 18 (see 3GPP document RP-223520 (Revised WID on Further NR mobility enhancements). One of the research objectives of this project is to implement a conditional primary cell (PCell) change configuration in a dual connectivity (DC) scenario, which includes a process for adding or changing the configuration of a conditional primary secondary cell (PSCell). More specifically, simultaneous conditional primary cell switching can be achieved while conditional primary and secondary cell group cells can be added or changed, thereby supporting better dual connectivity continuity in the conditional switching scenario and improving throughput during the switching process.

[0003] The present disclosure proposes a solution to the link failure problem during conditional PSCell addition or change in an NR system, in order to implement conditional PCell switching.

[0004] Summary of the Invention

[0005] The purpose of the embodiments of the present disclosure is to propose a solution to the problem of how to implement the conditional PSCell addition or change included in the conditional handover (CHO) in the NR system. More specifically, the present disclosure proposes a solution for the execution process of the CPAC and CHO processes when the UE is configured with the conditional PSCell addition or change (CPAC) included in the CHO configuration in the NR system. The embodiments of the present disclosure provide a method for executing the CPAC and CHO processes executed in the user equipment and the corresponding user equipment.

[0006] According to the first aspect of the present disclosure, a wireless link recovery method is proposed, including: a user equipment UE receives a conditional switching CHO configuration from a network side; a radio link control RRC re-establishment process is initiated to perform cell selection; when the selected suitable cell is a CHO candidate cell including a CHO configuration including a conditional primary and secondary cell addition and change CPAC configuration, if the execution condition of the CPAC candidate cell in the CPAC configuration is met, the CHO configuration including the CPAC configuration corresponding to the CPAC candidate cell is applied to perform link recovery; otherwise, the CHO configuration including the CPAC configuration corresponding to the CPAC candidate cell with the best signal quality is applied to perform link recovery.

[0007] In the wireless link recovery method of the first aspect above, the CHO configuration received from the network side includes a traditional CHO configuration or a CHO configuration including a CPAC configuration; the traditional CHO configuration does not include an SCG configuration or does not include a CPAC configuration; the CHO configuration including a CPAC configuration includes one or more configuration items, wherein a configuration item includes a CHO reconfiguration identifier, a CHO execution condition, a CPAC execution condition, and an RRC reconfiguration message including a primary cell group configuration and a secondary cell group configuration.

[0008] In the wireless link recovery method of the first aspect above, the UE receives first indication information from the network side. When the first indication information exists or is set to TRUE, the UE applies the CHO configuration including the CPAC configuration to perform link recovery; the first indication information is used to indicate whether the UE can apply the CHO configuration including the CPAC configuration to achieve link recovery during the RRC re-establishment process.

[0009] In the radio link recovery method of the first aspect above, when the first indication information does not exist or is set to FALSE, if the selected cell is a CHO candidate cell, the UE applies the traditional CHO configuration corresponding to the selected cell to perform link recovery.

[0010] In the radio link recovery method of the first aspect above, the first indication information is included in the CHO configuration and configured to the UE; the first indication information is included in the CHO configuration only when the UE is configured with the CHO configuration including the CPAC configuration.

[0011] In the wireless link recovery method of the first aspect above, if the execution conditions of the CPAC candidate cell corresponding to the selected cell in multiple CHO configurations are met; the UE applies the CHO configuration containing the CPAC configuration corresponding to the CPAC candidate cell with the best signal quality among the multiple CPAC candidate cells that meet the execution conditions to perform link recovery.

[0012] In the radio link recovery method of the first aspect, the UE applying the CHO configuration means that the UE applies the configuration in the RRC reconfiguration message included in the saved CHO configuration corresponding to the selected cell and performs corresponding operations.

[0013] 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 method for performing radio link failure recovery during the cell change process described in the context. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For a more complete understanding of the present disclosure and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, in which:

[0015] FIG1 is a schematic diagram showing a CHO configuration including a CPAC configuration.

[0016] FIG2 is another schematic diagram showing a CHO configuration including a CPAC configuration.

[0017] FIG3 is a flowchart showing a link recovery execution method in embodiment 1 of the present disclosure.

[0018] FIG4 is a flowchart showing a link recovery execution method in embodiment 2 of the present disclosure.

[0019] FIG5 is a block diagram showing a user equipment UE involved in the present disclosure.

[0020] In the drawings, the same or similar structures are marked with the same or similar reference numerals. DETAILED DESCRIPTION

[0021] 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.

[0022] In this disclosure, the terms "include" and "including" and their derivatives mean inclusion without limitation; the term "or" is inclusive, meaning and / or.

[0023] 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.

[0024] The following describes multiple embodiments of the present disclosure using the Long Term Evolution (LTE) / NR mobile communication system and its subsequent evolutionary versions as example application environments. 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. The cell changes involved in the present disclosure include handover and PSCell changes. Handover refers to the change of the primary cell (PCell), that is, the primary cell of the UE is changed from the source primary cell to the target primary cell, where the source primary cell and the target primary cell can be the same cell or different cells. The source primary cell refers to the cell serving the UE connected before the handover process is initiated, that is, the cell that sends a radio resource control (RRC) message containing a handover command to the UE. The target primary cell refers to the cell serving the UE to which the UE is connected after the handover process is successfully completed, the cell indicated by the target cell identifier contained in the handover command, or the cell described as performing downlink synchronization and random access during the handover process. Similarly, PSCell change refers to a change in the PSCell, which can be a cell change within a secondary base station (SN) or a cell change across SNs. The PSCell before the cell change is called the source PSCell, and the PSCell after the cell change is called the target PSCell. The addition of PSCell means that the UE enters the DC state configured with PSCell by adding a PSCell configuration from the non-DC state without PSCell. The PSCell added in this scenario is also called the target PSCell. In this disclosure, unless otherwise specified, cells, base stations, beams, transmission points (Transmission point, TRP), and cell groups (Cell Group, CG) can be replaced. For example, the source main cell, source base station, source beam, source TRP, source main cell group, etc. can be replaced; the target main cell, target base station, or target beam, target transmission point, target main cell group can be replaced; the source PSCell, source secondary base station, source secondary cell group can be replaced; the target PSCell, target secondary base station or target secondary cell group can be replaced. The switching command or PSCell addition or change command described in the present disclosure is an RRC reconfiguration message containing a synchronous reconfiguration (Reconfiguration with sync) information element in the NR system. Furthermore, the RRC reconfiguration message including a synchronous reconfiguration (Reconfigurationwithsync) information element for the primary cell group MCG is used for handover of the primary cell PCell, and the reconfigurationwithsync information element includes a target primary cell identifier or frequency information.The synchronous reconfiguration (Reconfigurationwithsync) information element containing the configuration of the primary and secondary cell group SCG is used for the addition or change of PSCell, and the reconfigurationwithsync information element contains the target primary and secondary cell identifier or frequency information. Therefore, switching can also be called synchronous reconfiguration of MCG, and PSCell addition or change is also called synchronous reconfiguration of SCG. For the convenience of description, the RRC reconfiguration message and the RRC connection reconfiguration message are equivalent in this disclosure; similarly, its response message RRC reconfiguration completion message and the RRC connection reconfiguration completion message are equivalent. Synchronous reconfiguration is equivalent to the RRC message containing synchronous reconfiguration. Cancellation, release, deletion, clearing and clearing can be replaced. Execution, use and application can be replaced. Configuration and reconfiguration can be replaced. Monitoring (monitor) and detection (detect) can be replaced. For the convenience of description, PSCell change includes both PSCell change and PSCell addition.

[0025] The following describes processes or concepts in the prior art to which this disclosure relates.

[0026] Handover configuration in NR system:

[0027] In the NR system, the RRC reconfiguration message for the handover command carries the RRC configuration from the target base station, including but not limited to the following RRC configuration (see section 6.2.2 of 3GPP technical standard protocol 38.331-h40 for details):

[0028] - measurement configuration;

[0029] -Cell group configuration (cellGroupConfig information element), used to configure the primary cell group or secondary cell group. It includes the radio link control (RLC) bearer configuration (rlc-bearerToAddModList information element and rlc-bearerToreleaselist information element) corresponding to the data radio bearer / signaling radio bearer, medium access control (MAC) configuration (MAC-cellgroupconfig information element), physical layer configuration, secondary cell addition / modification / release configuration, special cell (SpCell) configuration, etc. Among them, the reconfigurationwithsync information element contained in the SpCell configuration (spCellConfig information element) is similar to the mobility control information in the LTE system, and contains handover-related information to achieve mobility. It includes serving cell configuration public information (such as the identity and frequency information of the target serving cell), the cell radio network temporary identifier C-RNTI of the UE in the target cell, the handover process monitoring timer T304 configuration, and the random access dedicated configuration used for the random access process to the target cell.

[0030] -Radio bearer configuration (radiobearerConfig information element), used to configure the Service Data Application Protocol (SDAP) and Packet Data Convergence Protocol (PDCP) layers of the Data Radio Bearer (DRB) and / or Signaling Radio Bearer (SRB).

[0031] -Master key update configuration (masterKeyupdate information element).

[0032] Dual Connectivity (DC):

[0033] In order to improve the data transmission efficiency of the UE, the UE establishes links with two base stations at the same time, that is, the radio resources used by the UE are provided by different schedulers located in the two base stations. The radio access between the two base stations and the UE can be the same or different standards (Radio Access Technology, RAT), such as both are NR, or one is NR and the other is LTE, also known as Evolved Universal Terrestrial Radio Access, E-UTRA. Among the two base stations, one is called the Master Node (MN) or MgNB, MeNB, and the service cell group under the Master Node is called the Master Cell Group (MCG); the other is called the Secondary Node (SN) or SgNB, SeNB, and the service cell group under the Secondary Node is called the Secondary Cell Group (SCG). The MCG contains at least one Primary Cell (PCell) and, optionally, one or more Secondary Cells (SCell). The PCell operates on the primary frequency, and the UE performs the initial connection establishment process or the connection re-establishment process through the primary frequency. An SCG contains at least one PSCell and, optionally, one or more SCells. A PSCell is the SCG cell to which a UE performs random access when performing a synchronous reconfiguration procedure or an SCG addition procedure. PCells and PSCells are collectively referred to as special cells (SpCells).

[0034] Handover process in NR system:

[0035] User mobility in a connected primary cell is primarily achieved through a handover process, which refers to the process by which a UE in an RRC connected state changes its serving cell (primary cell). A typical handover process consists of the following phases: Phase 1: Measurement phase. The UE measures the radio link corresponding to the serving cell or neighboring cell based on the configured measurement configuration. When the configured measurement reporting conditions are met, the UE sends a measurement report to the base station. Phase 2: Handover preparation phase. The base station determines whether to trigger a handover for the UE based on the received measurement report and other factors, such as base station load. The source and target base stations obtain the handover command configured by the target base station through the handover preparation process. Phase 3: Handover execution phase. The source base station issues the handover command to the UE, which immediately applies the configuration of the handover command to execute the handover. The UE uses a timer, T304, to monitor the handover process. When the handover process is initiated, the UE starts T304; when the handover process is complete, the UE stops T304; when T304 expires, the UE considers the handover to have failed. The above handover process also applies to the PSCell change process.

[0036] Unlike the general handover process in stage 3, in which the UE performs handover immediately after receiving the handover command, the NR system also supports conditional handover CHO, also known as conditional reconfiguration. In conditional handover, a relatively conservative measurement report threshold is set so that the base station obtains the measurement results in advance and performs handover preparation in advance based on the measurement results and the selected target base station. In this way, the base station can send a handover command containing the handover candidate cell and the handover execution condition to the UE in advance before the actual handover condition (relative to the conservative measurement report threshold) is met, which carries the conditions for the UE to perform handover. After receiving the conditional handover command, the UE does not perform handover immediately, but saves the received handover command configuration and starts monitoring the link quality of the source cell or the link quality of the target cell according to the handover execution condition carried in the handover command message to evaluate whether the handover execution condition is met. Only when it is monitored that the configured handover execution condition is met, the UE starts to execute the saved handover command and accesses the target cell. The UE can be configured with multiple conditional handover candidate cells at the same time. If multiple conditional handover candidate cells meet the handover execution condition at the same time, the UE selects one candidate cell from them as the final conditional handover target cell and performs handover to that cell. In short, conditional handover refers to a handover process that is executed only when one or more configured handover execution conditions are met. Because the handover command is included in the RRC reconfiguration message, conditional handover is also called conditional reconfiguration.

[0037] PSCell change process in NR system

[0038] The PSCell change process in the NR system is triggered by the UE through the RRC reconfiguration message containing the synchronization reconfiguration information element for SCG. The PSCell change process can be initiated by the MN or the SN. When the Signaling Radio Bearer (SRB) 3 is configured, the SN can autonomously initiate the PSCell change process without the participation of the MN. At this time, the SN sends the PSCell change command for the SCG to the UE on SRB3. Generally speaking, the PSCell change initiated by the SN autonomously through SRB3 is Intra-SN, that is, the PSCell change within the same secondary base station. When SRB3 is not configured, whether the PSCell change process is initiated by the SN or the MN, the PSCell change command is sent to the UE on SRB1, including intra-SN or inter-SN PSCell changes. The RRC reconfiguration message of the PSCell change command for SN is included in the nr-SecondaryCellGroupConfig information element (when E-UTRAN is MN) or the mrdc-SecondaryCellGroup information element (when NR is MN) of its outer RRC message. The outer message is generally an RRC (connection) reconfiguration message or a DLInformationTransferMRDC message. The UE that receives the PSCell change command executes the PSCell change process, starts the timer T304 for monitoring the process of the SCG, starts downlink synchronization to the target PSCell, applies the configuration of the RRC reconfiguration message including the synchronization reconfiguration for the SCG, and sends an RRC reconfiguration completion message to the network side. Depending on the outer message of the received PSCell change command, the RRC reconfiguration completion message may also be embedded in an outer RRC message, such as an RRC (connection) reconfiguration completion message or a ULInformationTransferMRDC message.

[0039] After the introduction of conditional reconfiguration in the NR system, conditional reconfiguration is supported for adding or changing PSCells. Similar to conditional switching CHO, the UE is configured with conditional reconfiguration for SCG, which means that the conditional reconfiguration containing PSCell candidate cells and execution conditions is sent to the UE. After receiving the conditional reconfiguration, the UE does not immediately execute the addition or change of the PSCell candidate cells contained therein, but saves the received conditional reconfiguration and starts monitoring the link quality of the source cell or the link quality of the target candidate cell according to the execution conditions carried therein to evaluate whether the execution conditions are met. Only when it is monitored that the configured execution conditions are met, the UE starts to execute the SCG configuration in the saved conditional reconfiguration and accesses the selected PSCell candidate cell. Like CHO, the UE can be configured with multiple PSCell candidate cells at the same time. If multiple candidate cells meet the execution conditions at the same time, the UE selects one candidate cell as the final target PSCell cell and synchronizes to the cell. Conditional reconfiguration for SCGs is referred to as Conditional PSCell Addition Change (CPAC). Conditional PSCell Addition is also known as CPA (Conditional PSCell Addition), and Conditional PSCell Change is also known as CPC (Conditional PSCell Change). For ease of description, CPAC in this disclosure may refer to either CPC or CPA.

[0040] Conditional reconfiguration

[0041] As mentioned above, conditional reconfiguration can be applied to MCG or SCG. The conditional reconfiguration of MCG / PCell is called conditional handover CHO; the conditional reconfiguration of SCG / PSCell is called conditional PSCell addition or change CPAC. In the NR system, conditional reconfiguration is configured to the UE through the conditional reconfiguration ConditionalReconfiguration information element in the RRC message. The ConditionalReconfiguration information element contains a list of conditional reconfiguration candidate cells (condReconfigToAddModList information element for adding or modifying candidate cells or condReconfigToRemoveList information element for removing candidate cells). The UE saves the configuration corresponding to one or more of the conditional reconfiguration candidate cells in the UE variable VarConditionalReconfig. In the NR system of version 17, the UE maintains two VarConditionalReconfig variables, which are used to save the CHO configuration of the MCG and the CPAC configuration of the SCG respectively. Among the one or more conditional configuration items stored in each variable, each item is identified by a conditional reconfiguration identifier (condReconfigId), including an execution condition (condExecutionCond or condExecutionCondSCG) and the RRC configuration of the candidate cell (condRRCReconfig). The RRC configuration of the candidate cell contains a nested RRC reconfiguration message, in which the cell identified by the cell identifier in the serving cell common configuration (servingCellConfigCommon information element) in the synchronous reconfiguration (reconfigurationWithSync information element) corresponds to a conditional reconfiguration candidate cell. The UE performs conditional reconfiguration evaluation on each conditional reconfiguration candidate cell based on the execution condition. The execution condition can include one or two measurement identifiers (measID). Only when the measurement events corresponding to all measurement identifiers included in the execution condition (such as condEventA3 or CondEventA5 included in the CondTriggerConfig information element) are met, the UE considers the corresponding candidate cell to be a triggering cell and initiates the conditional reconfiguration execution process.During the conditional reconfiguration execution process, the UE applies the saved RRC configuration (condRRCReconfig) corresponding to the selected triggering cell to the selected cell and performs the cell change operation, such as starting timer T304, downlink synchronization to the selected cell, initiating a random access process to the selected cell for uplink synchronization, and sending an RRC reconfiguration completion message to the selected cell (see section 5.3.5.3 of the 3GPP protocol specification document TS38.331 for details, which will not be repeated here). In this disclosure, unless otherwise specified, CHO and CHO configurations can be replaced, and CPAC and CPAC configurations can be replaced.

[0042] Radio Link Failure (RLF) or Handover Failure (HOF) recovery:

[0043] When the UE detects RLF of the master cell group or a handover failure (including general handover failure and conditional handover failure) occurs due to the timeout of T304 associated with the master cell group, it will initiate an RRC connection re-establishment process to re-establish / restore the connection with the network side. In the initiated RRC connection re-establishment process, the UE first performs a cell selection process to select a suitable cell. In the case where there is a saved conditional reconfiguration on the UE, if the UE is configured with an enable indication (attemptCondReconfig information element) that CHO can be performed after link failure, and the cell selection process is due to the detection of MCG RLF or MCG handover failure (i.e., synchronous reconfiguration failure in the NR system) and the selected cell is a conditional handover candidate cell (the synchronous reconfiguration information element reconfigurationWithSync corresponding to the selected cell is included in the MasterCellGroup information element in the saved conditional reconfiguration variable), the UE applies the configuration in the conditional reconfiguration according to the conditional handover configuration corresponding to the cell, and performs handover to the cell (see section 5.3.5.3 of the 3GPP protocol specification document TS38.331-h40), ending the link recovery process. Otherwise, the UE attempts to restore its connection with the network by sending an RRC Connection Reestablishment Request to the selected cell. If the UE receives an RRC Connection Reestablishment Message as a response, it reestablishes the RRC connection according to the configuration in the RRC Connection Reestablishment Message and sends an RRC Connection Reestablishment Complete Message back to the base station, successfully completing the RRC Connection Reestablishment process. If the RRC Reestablishment process fails, the UE leaves the RRC Connected State and enters the RRC Idle State.

[0044] For the convenience of description, the link recovery of conditional handover performed through the conditional reconfiguration candidate cell selected in the RRC re-establishment process is called conditional handover recovery.

[0045] LTM (L1 / L2 Triggered Mobility) mechanism:

[0046] The 3GPP working group is currently discussing and specifying standards for the LTM mechanism. According to the conclusions reached so far, LTM can be used for service cell changes in the main cell group MCG, such as changes in the main cell PCell, and can also be used for service cell changes in the secondary cell group SCG. The cell change using the LTM mechanism is called cell switch to distinguish it from traditional handover. The network side sends the LTM candidate cell configuration (LTM-Config) 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 UE saves the received LTM configuration in the UE variable VarLTM-Config, or the UE saves the LTM configuration generated according to the LTM candidate cell configuration in VarLTM-UE-Config. The candidate cell configuration includes an RRC configuration list (ltm-CandidateToAddModList) corresponding to one or more candidate cells. The configuration of each candidate cell in the list is represented by the LTM-Candidate information element and identified by ltm-CandidateId. Based on the Layer 1 measurement results reported by the UE, the network determines the target cell for the final cell change and triggers the cell switch process through Layer 1 / Layer 2 (L1 / L2) signaling (such as a MAC control element (CE)). The L1 / L2 signaling used to trigger the cell switch process contains at least an indication 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.

[0047] LTM and CHO are similar in that the RRC reconfiguration for a candidate cell is delivered to the UE in advance, before the actual cell change is triggered. Similar to the conditional handover recovery mechanism, whether the UE can utilize the saved LTM configuration to perform LTM-based link recovery during RRC reestablishment is currently under discussion within the 3GPP working group.

[0048] CHO with candidate SCG for CPAC:

[0049] The NR system of version 17 supports CHO including SCG configuration, that is, for each CHO candidate cell configuration, in addition to the corresponding MCG configuration, it can also include SCG configuration. This solution that supports both CHO and DC during mobility allows the UE to be in DC state in the target cell immediately after switching to the target cell through CHO, thereby increasing or maintaining the UE throughput during the switching process. However, because the CHO configuration is sent to the UE in advance before the actual switching is triggered, the UE may trigger the CHO some time after the CHO configuration is received. Then, when the CHO is executed, the SCG configuration contained therein may not be appropriate, which will cause SCG failure during the CHO execution process (such as failure to add or change PSCell).

[0050] In the mobility enhancement discussion of Release 18 currently underway in 3GPP, in order to solve the above-mentioned problem, it is proposed that the CHO configuration can be associated with one or more CPAC configurations. Unlike Release 17, which contains a fixed SCG configuration in the CHO configuration, the CHO configuration proposed in Release 18 can contain or be associated with one or more candidate SCG configurations, and each candidate SCG configuration is equivalent to a CPAC configuration. When the UE receives the CHO configuration and the associated CPAC configuration, it can simultaneously start the CHO conditional reconfiguration evaluation and the corresponding associated CPAC conditional reconfiguration evaluation. In this way, when the execution condition of CHO is met, that is, when CHO is triggered, the UE can select the most suitable SCG configuration from multiple candidate SCG configurations according to the corresponding CPAC execution condition evaluation for PSCell access. This can greatly reduce the problem of SCG failure or SCG inappropriateness in the CHO process caused by only one fixed SCG configuration in the CHO configuration in Release 17. In this disclosure, the CHO configuration in this newly introduced mechanism is referred to as a CHO configuration associated with a CPAC configuration, a CHO configuration containing a CPAC configuration, a CHO configuration with a candidate SCG for CPAC, or a CHO configuration with a candidate CPAC (configuration). However, it is worth noting that this disclosure is not limited to the above nomenclature.

[0051] In the CHO configuration that includes the CPAC configuration, the RRC message in the CHO configuration (CHO container) contains an MCG configuration, an SCG configuration, a CHO execution condition, and a CPAC execution condition, and is identified by a CHO identification number CondReconfigId, as shown in Figure 1. If a CHO candidate cell is associated with multiple CPAC candidate configurations, then for this CHO candidate cell, the network side will configure multiple CHO configurations for the UE, and each CHO configuration contains an MCG configuration and an SCG configuration. That is, the CHO candidate cell identifiers in multiple conditional reconfigurations (identified by condReconfigId) can be the same, but have different CPAC candidate cell identifiers. As shown in Figure 2, multiple CHO configurations are configured for PCell 1, each CHO configuration corresponds to a different PSCell, and these multiple CHO configurations are identified by different CondReconfigId.

[0052] In the above scenario, when the UE receives an RRC message containing the CPAC configuration of CHO and the associated alternative SCG, the UE saves the received CHO configuration and CPAC configuration, and starts the corresponding conditional reconfiguration evaluation at the same time. According to the conclusion reached by the 3GPP working group, only when the execution conditions of CHO are met and the associated CPAC execution conditions are also met, the UE triggers and executes the CHO process accompanied by CPAC, and triggers and completes the switching and PSCell addition or change. If the execution conditions of CHO are met but the execution conditions of the associated CPAC are not met, in this case, if the UE is configured with the traditional CHO configuration, the UE triggers the execution of the CHO process and applies the configured traditional CHO configuration. In the present disclosure, the traditional CHO configuration generally refers to a CHO configuration that is not associated with CPAC, or a CHO configuration that does not include a CPAC configuration, such as the CHO configuration that does not include an SCG configuration introduced in version 16 or the CHO configuration that includes an SCG configuration introduced in version 17 (which does not include the CPAC execution condition configuration corresponding to the SCG configuration).

[0053] As mentioned above, when RLF or HOF occurs, in the cell selection phase of the RRC re-establishment process, if the selected cell is a CHO candidate cell in the CHO configuration saved by the UE, then the UE applies the CHO configuration of the cell and performs CHO-based recovery. In the NR system of version 17, each CHO candidate cell will only be configured with one CHO configuration, and the UE can directly execute the CHO configuration corresponding to the selected CHO candidate cell. In the above-mentioned new mechanism introduced in version 18, if the UE is configured with a CHO configuration including a CPAC configuration, for the same CHO candidate cell, the UE may be configured with multiple CHO configurations, where each CHO configuration may not be associated with an SCG configuration or may be associated with a different CPAC configuration. For example, in the example of Figure 2, the same PCell 1 can be associated with different CPAC candidate PSCells 1 to 3 in different CHO configurations. In this case, how the UE selects the CHO configuration of the selected CHO candidate cell is the issue of concern in this disclosure. In addition, if the UE is configured with conditional handover recovery and LTM-based link recovery in addition to conditional handover recovery, then if the selected cell is both a CHO candidate cell and an LTM candidate cell, that is, the selected cell is associated with both a CHO configuration and an LTM configuration, then which configuration the UE should apply to achieve link recovery also becomes a problem of concern in this disclosure. Furthermore, if the execution conditions of CHO are met and the corresponding execution conditions of CPAC are not met, in this case, if the UE applies the configured traditional CHO configuration (i.e., a CHO configuration that does not include a CPAC configuration), then how the UE handles the configured CPAC configuration or whether it considers that the configured CPAC execution has failed is also a problem of concern in this disclosure.

[0054] The following embodiments provide solutions to the above-mentioned problems. Unless otherwise specified, some concepts or definitions are common among the embodiments, and different embodiments can be implemented in combination and are not mutually exclusive.

[0055] Example 1

[0056] This embodiment provides a link recovery method performed on the UE. For the scenario described above, during the RRC re-establishment process, if the selected cell is a CHO candidate cell in the CHO configuration saved by the UE, and for this CHO candidate cell, if the UE is configured with multiple CHO configurations including CPAC configurations, then the UE selects one of the CHO configurations based on the method described in this embodiment, applies the CHO configuration, and executes the corresponding RRC reconfiguration process to achieve link recovery. Through the method, the UE can also select a more appropriate SCG configuration during the CHO recovery process, so that after the link is restored, the UE can remain in the DC state to ensure the UE's throughput.

[0057] In this embodiment, the UE initiates an RRC re-establishment procedure and performs a cell selection procedure. If the selected cell is a candidate cell in a CHO configuration that includes a CPAC configuration, and if the execution conditions corresponding to the CPAC configuration included in a CHO configuration stored by the UE for the candidate cell are met, the UE applies the CHO configuration. Otherwise, the UE applies the measurement results of the CPAC candidate cell included in the stored CHO configuration for the candidate cell to the best CHO configuration.

[0058] As an example, FIG3 is a flow chart showing the execution method in Example 1 of the present disclosure. As shown in FIG3 , as an implementation method of Example 1, the following steps are included:

[0059] Step 110: The UE initiates an RRC re-establishment process and performs a cell selection process.

[0060] Step 120 : When a suitable cell is selected, if the selected cell is a CHO candidate cell, the UE executes step 130 .

[0061] Optionally, the selected cell is a CHO candidate cell, which means that the selected cell is a candidate cell, and the synchronization reconfiguration information element reconfigurationWithSync corresponding to the candidate cell is included in the master cell group configuration masterCellGroup information element in the UE variable VarConditionalReconfig used to save the CHO configuration.

[0062] Step 120 is an optional step.

[0063] Step 130 : The UE further determines whether the selected cell includes a candidate PCell cell in the CHO configuration of the CPAC configuration. If the UE determines that the selected cell is a candidate PCell cell in the CHO configuration including the CPAC configuration, the UE executes step 140 .

[0064] Step 140: If the execution conditions corresponding to the candidate CPACs in one or more CHO configurations corresponding to the selected cell are met, the UE executes step 150; otherwise, if the execution conditions corresponding to the candidate CPACs in one or more CHO configurations corresponding to the selected cell are not met, the UE executes step 160.

[0065] Optionally, the execution condition corresponding to the candidate CPAC being met can also be expressed as the candidate CPAC cell being a triggered cell.

[0066] Optionally, the execution condition corresponding to the candidate CPAC also includes that the measurement result of the execution condition corresponding to the CPAC does not satisfy a configured leaving condition.

[0067] Step 150: Apply the CHO configuration, including applying the CPAC configuration in the CHO configuration, and performing operations corresponding to the RRC reconfiguration in the CHO configuration.

[0068] Optionally, if the execution conditions corresponding to the candidate CPACs in the multiple CHO configurations corresponding to the selected cell are all met, the UE selects the CHO configuration corresponding to the candidate CPAC with the best signal quality (best measurement result) from the multiple CHO configurations of the candidate CPACs with the execution conditions met for application.

[0069] Step 160: If none of the execution conditions corresponding to the candidate CPACs in one or more CHO configurations corresponding to the selected cell are met, then a CHO configuration corresponding to the candidate CPAC with the best signal quality (best measurement result) is selected from the multiple CHO configurations for application.

[0070] Optionally, applying the CHO configuration refers to applying the saved condRRCReconfig.

[0071] Optionally, the execution order of the above operations is not limited.

[0072] Obviously, before step 110, the UE also includes receiving the CHO configuration or the CHO configuration including the CPAC configuration, and saving the received CHO configuration in the corresponding UE variable as described above.

[0073] Optionally, the CPAC configuration or candidate CPAC in the aforementioned CHO configuration refers to a CPAC configuration associated with the CHO configuration. As described in the background section, the evaluation or execution of such a CPAC configuration is linked to the CHO configuration or execution. For example, even if the execution conditions corresponding to the CPAC are met, the application or execution of the CPAC configuration can only be performed when the CHO process is triggered / applied. In other words, the evaluation or execution of the CPAC configuration is dependent on the evaluation or execution of the associated CHO configuration.

[0074] Example 2

[0075] This embodiment provides a link recovery method performed on a UE. For the scenario described above, during the RRC re-establishment process, if the selected cell is a CHO candidate cell in the CHO configuration saved by the UE, and for this CHO candidate cell, if the UE is configured with multiple CHO configurations including CPAC configurations, then based on the method described in this embodiment, the UE can determine whether a CHO configuration can be selected and execute the corresponding RRC reconfiguration process to achieve link recovery. Through the method, the UE can determine whether to select an SCG configuration to remain in the DC state according to the instructions on the network side during the CHO recovery process.

[0076] In this embodiment, the UE initiates an RRC re-establishment process and performs a cell selection process. If the selected cell is a candidate cell in a CHO configuration including a CPAC configuration and the UE is enabled for link recovery based on a CHO configuration including a CPAC configuration, the UE applies a CHO configuration including a CPAC configuration. Otherwise, the UE applies the saved CHO configuration corresponding to the selected cell that does not include a CPAC configuration to perform link recovery, or the UE continues to perform the RRC re-establishment process and initiates the sending of an RRC re-establishment request message.

[0077] In this embodiment, the network side displays the configuration of whether the UE can apply the CHO configuration including the CPAC configuration to perform link recovery during the RRC re-establishment process (enable indication). Taking into account that the network side is aware of the UE context and the wireless environment and service attributes of the UE, the network side can configure whether the UE applies the CHO configuration including the CPAC configuration to perform link recovery, so as to achieve the goal of not affecting the success rate of RRC re-establishment and maximizing the retention of the UE's DC state after link recovery. For the case where the UE is configured with both the traditional CHO configuration and the CHO configuration including the CPAC configuration, the UE can determine whether to apply the CHO configuration including the CPAC configuration to perform link recovery or the traditional CHO configuration to perform link recovery based on the enable indication when the selected cell is a CHO candidate cell. For example, when the cell selected during the RRC re-establishment process is a CHO candidate cell, if the network side configures the UE with the enabling indication, the UE applies a CHO configuration corresponding to the selected cell that includes a CPAC configuration to perform link recovery; if the UE is not configured with the enabling indication, the UE applies the traditional CHO configuration corresponding to the selected cell to perform link recovery.

[0078] As an example, FIG4 is a flow chart showing the execution method in Example 2 of the present disclosure. As shown in FIG4 , as an implementation method of Example 2, the following steps are included:

[0079] Step 210: The UE initiates an RRC re-establishment process and performs a cell selection process.

[0080] Step 220 : When a suitable cell is selected, if the selected cell is a CHO candidate cell and the UE is configured with the first indication information (ie, the aforementioned enabling indication), the UE executes step 230 ; otherwise, the UE executes step 240 .

[0081] Optionally, the selected cell is a CHO candidate cell, which means that the selected cell is a candidate cell, and the synchronization reconfiguration information element reconfigurationWithSync corresponding to the candidate cell is included in the master cell group configuration masterCellGroup information element in the UE variable VarConditionalReconfig used to save the CHO configuration.

[0082] The first indication information is used to indicate whether the UE can apply the CHO configuration including the CPAC configuration to achieve link recovery during the RRC re-establishment process. Optionally, if the first indication information exists or is configured as "TRUE", it means that the network side has configured / enabled the application of the CHO configuration including the CPAC configuration to achieve link recovery during the RRC re-establishment process. Optionally, the existence of the first indication information means that the first indication information exists in the RRC message received by the UE from the network side. Furthermore, the first indication information is included in the CHO configuration and configured to the UE, such as in the ConditionalReconfiguration information element. Optionally, the UE is configured with the first indication information only when it is configured with the CHO configuration including the CPAC configuration. That is, if the UE is not configured with the CHO configuration including the CPAC configuration, the UE will not be configured with the first indication information.

[0083] Optionally, in this step, when a suitable cell is selected, if the selected cell is a CHO candidate cell, the UE further determines if the selected cell is a CHO candidate cell in a CHO configuration including a CPAC configuration, and the UE is configured with the first indication information, and the UE executes step 230.

[0084] Step 230: The UE applies a CHO configuration including a CPAC configuration corresponding to the selected cell and performs operations corresponding to the CHO configuration (ie, performs related operations based on the content in the RRC reconfiguration message in the CHO configuration).

[0085] Optionally, in this step, when the UE further determines that the selected cell is configured with a CHO configuration having an SCG configuration for CPAC, the UE performs the operation in this step.

[0086] Optionally, if the selected cell corresponds to more than one CHO configuration with an SCG configuration for CPAC, i.e., multiple CHO configurations including CPAC configurations, the UE selects one CHO configuration from among them for application. Optionally, the method for the UE to select a CHO configuration from multiple applicable CHO configurations can be based on the method described in Example 1 or Example 5.

[0087] Step 240: The UE applies the CHO configuration corresponding to the selected cell, or the UE continues the RRC re-establishment process by initiating an RRC re-establishment request message.

[0088] Optionally, if the UE is not configured with the above-mentioned first indication information or the selected cell is not configured with a CHO configuration with an SCG configuration for CPAC, the UE applies the CHO configuration corresponding to the selected cell. The CHO configuration refers to a traditional CHO configuration, that is, a CHO configuration that does not include a CPAC configuration. The UE applies the CHO configuration corresponding to the selected cell when the selected cell is a candidate cell in the traditional CHO configuration.

[0089] Optionally, if the UE is not configured with the above-mentioned first indication information or the selected cell is not configured with a CHO configuration with an SCG configuration for CPAC or the selected cell is not configured with a traditional CHO configuration, the UE initiates an RRC re-establishment request message.

[0090] Optionally, applying the CHO configuration refers to applying the saved condRRCReconfig.

[0091] Optionally, the execution order of the above operations is not limited.

[0092] Optionally, before step 210, the UE receives a CHO configuration or a CHO configuration including a CPAC configuration, and saves the received CHO configuration in a corresponding UE variable as described above.

[0093] Optionally, the CPAC configuration or candidate CPAC in the aforementioned CHO configuration refers to a CPAC configuration associated with the CHO configuration. As described in the background section, the evaluation or execution of such a CPAC configuration is linked to the CHO configuration or execution. For example, even if the execution conditions corresponding to the CPAC are met, the application or execution of the CPAC configuration can only be performed when the CHO process is triggered / applied. In other words, the evaluation or execution of the CPAC configuration is dependent on the evaluation or execution of the associated CHO configuration.

[0094] Example 3

[0095] This embodiment provides a link recovery method performed on a UE. As previously mentioned, considering that both the CHO and LTM mechanisms are intended to improve the mobility performance of the UE in a connected state, the UE can be configured with both the CHO configuration and the LTM configuration. The present disclosure proposes a method for determining whether to restore the link based on the CHO configuration or the LTM configuration during the RRC re-establishment process. Through the method described in this embodiment, when the cell selected during the RRC re-establishment process is both a CHO candidate cell and an LTM candidate cell, the UE can determine the link recovery method.

[0096] In one implementation, during the RRC re-establishment process, if the UE is configured with both the CHO and LTM configurations, the UE prioritizes the CHO configuration for link recovery. Specifically, the UE initiates the RRC re-establishment process and performs cell selection. The UE first determines whether the selected cell is a CHO candidate cell. If the selected cell is a CHO candidate cell, the UE applies the stored CHO configuration corresponding to the selected cell and performs RRC connection reconfiguration operations in the CHO configuration. Otherwise, the UE determines whether the selected cell is an LTM candidate cell. If so, the UE applies the stored LTM configuration corresponding to the selected cell and performs an LTM cell switch.

[0097] In another implementation, during the RRC re-establishment process, if the UE is configured with both the CHO and LTM configurations, the UE prioritizes the LTM configuration for link recovery. Specifically, the UE initiates the RRC re-establishment process and performs cell selection. The UE first determines whether the selected cell is an LTM candidate cell. If the selected cell is an LTM candidate cell, the UE applies the saved LTM configuration corresponding to the selected cell and performs an LTM cell switch. Otherwise, the UE determines whether the selected cell is a CHO candidate cell. If so, the UE applies the saved CHO configuration corresponding to the selected cell and performs RRC connection reconfiguration-related operations in the CHO configuration.

[0098] In another implementation, during the RRC re-establishment process, if the UE is configured with both the CHO configuration and the LTM configuration, the UE determines whether to use the CHO configuration or the LTM configuration to perform link recovery based on the instructions of the network side. Specifically, the UE initiates the RRC re-establishment process and performs cell selection. The third indication information configured on the UE indicates that the UE uses the CHO configuration to perform link recovery. When the selected cell is a CHO candidate cell, the UE applies the saved CHO configuration corresponding to the selected cell and performs RRC connection reconfiguration related operations in the CHO configuration. If the third indication information configured on the UE indicates that the UE uses the LTM configuration to perform link recovery, when the selected cell is an LTM candidate cell, the UE applies the saved LTM configuration corresponding to the selected cell and performs LTM cellswitch. The third indication information is configured to the UE by the network side through an RRC message to indicate whether the UE performs conditional reconfiguration or LTM when the selected cell is both a CHO candidate cell and an LTM candidate cell. Optionally, the third indication information may only exist when the UE is configured with both CHO configuration and LTM configuration.

[0099] Optionally, if the selected cell is a CHO candidate cell and the UE is configured with the attemptCondReconfig information element, the UE applies the saved CHO configuration corresponding to the selected cell.

[0100] Optionally, if the selected cell is an LTM candidate cell and the UE is enabled for LTM-based link recovery, the UE applies the saved LTM configuration corresponding to the selected cell. Optionally, the UE being enabled for LTM-based link recovery means that the UE is configured with second indication information, and the second indication information is used to indicate that if the selected cell is an LTM candidate cell (and this is the first cell selection after link failure), the UE executes the LTM configuration corresponding to the selected cell. Optionally, the second indication information is represented by an attemptLTMconfig or attemptLTMreconfig information element. Optionally, the second indication information can be represented by reusing the attemptCondReconfig information element in the existing mechanism.

[0101] Optionally, the selected cell is a CHO candidate cell, which means that the selected cell is a candidate cell, and the synchronization reconfiguration information element reconfigurationWithSync corresponding to the candidate cell is included in the master cell group configuration masterCellGroup information element in the UE variable VarConditionalReconfig used to save the CHO configuration.

[0102] Optionally, the selected cell is an LTM candidate cell, which means that the selected cell is a candidate cell, and the LTM cell switching information element ltm-CellSwitchInfo corresponding to the candidate cell is included in the master cell group configuration masterCellGroup information element in the UE variable used to store the LTM configuration.

[0103] Example 4

[0104] This embodiment provides a cell change method performed on a UE. Using the method described in this embodiment, for a UE configured with a CHO configuration that includes a CPAC configuration, if a traditional handover is performed, the UE can report to the network that it did not perform the CPAC configuration after the handover is completed. This allows the network to use the reported information to quickly configure an appropriate SCG for the UE, thereby improving the UE's throughput through DC.

[0105] In this embodiment, after the UE successfully completes the handover, if the UE is configured with a CHO configuration including a CPAC configuration in the source cell, the UE initiates an SCG failure information SCGFailureInformation process to indicate to the network side that the CPAC in the configured CHO configuration is not executed.

[0106] As an example, the embodiment may include the following steps:

[0107] Step 410: The UE successfully completes the handover.

[0108] Optionally, the UE successfully completing the handover means that the MAC layer successfully completes the random access process to the target base station.

[0109] Optionally, the handover refers to a conditional handover CHO. Furthermore, it refers to a CHO that does not include a CPAC configuration.

[0110] Step 420: If the UE is configured with a CHO configuration including a CPAC configuration in the source cell, or the UE has a saved CHO configuration including a CPAC configuration, the UE initiates an SCG failure information process and sends an RRC message of SCGFailureInformation to the network side.

[0111] Optionally, the RRC message includes at least the measurement result of the CPAC candidate cell. Optionally, the RRC message also includes execution condition information of the CPAC candidate cell (such as whether the configured execution condition is met).

[0112] Optionally, if the CHO configuration including CPAC configuration configured in the source cell of the UE or the CHO candidate cell identifier in the CHO configuration including CPAC configuration stored on the UE is the same as the target candidate cell of the handover completed in step 410, the UE executes step 420.

[0113] Optionally, if the UE is configured with a CHO configuration including a CPAC configuration in the source cell, or there is a CHO configuration including a CPAC configuration saved on the UE, when the UE successfully completes the switching in step 410, if the CHO configuration including the CPAC configuration saved on the UE is released, the UE executes step 420.

[0114] Optionally, if the CHO configuration including CPAC configuration configured in the source cell of the UE or the CHO candidate cell identifier in the CHO configuration including CPAC configuration saved on the UE is the same as the target candidate cell of the switching completed in step 410, and if the CHO configuration including CPAC configuration saved on the UE is released when the switching is triggered or when the switching is successful, the UE executes step 420.

[0115] Example 5

[0116] This embodiment provides another link recovery method performed on the UE. For the scenario described above, during the RRC re-establishment process, if the selected cell is a CHO candidate cell in the CHO configuration saved by the UE, and for this CHO candidate cell, if the UE is configured with multiple CHO configurations including CPAC configurations, then the UE selects one of the CHO configurations based on the method described in this embodiment, applies the CHO configuration, and executes the corresponding RRC reconfiguration process to achieve link recovery. Through the method, the UE can also select a more appropriate SCG configuration during the CHO recovery process, so that after the link is restored, the UE can remain in the DC state to ensure the UE's throughput.

[0117] In this embodiment, the UE initiates an RRC re-establishment procedure and performs a cell selection procedure. If the selected cell is a candidate cell in a CHO configuration that includes a CPAC configuration, and the selected cell corresponds to multiple CHO configurations that include a CPAC configuration, the UE applies the saved measurement results of the CPAC candidate cells included in the multiple CHO configurations for the candidate cell to the best CHO configuration.

[0118] As an implementation of Example 5, the following steps are included:

[0119] Step 510: The UE initiates an RRC re-establishment process and performs a cell selection process.

[0120] Step 520 : When a suitable cell is selected, if the selected cell is a CHO candidate cell, the UE executes step 530 .

[0121] Optionally, the selected cell is a CHO candidate cell, which means that the selected cell is a candidate cell, and the synchronization reconfiguration information element reconfigurationWithSync corresponding to the candidate cell is included in the master cell group configuration masterCellGroup information element in the UE variable VarConditionalReconfig used to save the CHO configuration.

[0122] Step 520 is an optional step.

[0123] Step 530 : The UE further determines whether the selected cell includes a candidate PCell cell in the CHO configuration of the CPAC configuration. If the UE determines that the selected cell is a candidate PCell cell in the CHO configuration including the CPAC configuration, the UE executes step 540 .

[0124] Step 540: If the selected cell corresponds to multiple CHO configurations including CPAC configurations, the UE selects a CHO configuration corresponding to a candidate CPAC with the best signal quality (best measurement result) among the multiple CHO configurations to apply.

[0125] Optionally, applying the CHO configuration refers to applying the saved condRRCReconfig.

[0126] Optionally, the execution order of the above operations is not limited.

[0127] Obviously, before step 510, the UE also includes receiving the CHO configuration or the CHO configuration including the CPAC configuration, and saving the received CHO configuration in the corresponding UE variable as described above.

[0128] Optionally, the CPAC configuration or candidate CPAC in the aforementioned CHO configuration refers to a CPAC configuration associated with the CHO configuration. As described in the background section, the evaluation or execution of such a CPAC configuration is linked to the CHO configuration or execution. For example, even if the execution conditions corresponding to the CPAC are met, the application or execution of the CPAC configuration can only be performed when the CHO process is triggered / applied. In other words, the evaluation or execution of the CPAC configuration is dependent on the evaluation or execution of the associated CHO configuration.

[0129] Example 6

[0130] This embodiment illustrates the user equipment UE disclosed in the present invention. FIG5 is a block diagram of the user equipment UE involved in the present invention. As shown in FIG5 , the user equipment UE 50 includes a processor 501 and a memory 502. The processor 501 may include, for example, a microprocessor, a microcontroller, an embedded processor, etc. The memory 502 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 502 stores program instructions. When the instructions are executed by the processor 501, the link recovery or cell change execution method described in detail in the present invention may be executed.

[0131] The method and related devices of the present disclosure have been described above in conjunction with preferred embodiments. Those skilled in the art will appreciate that the method shown above is merely exemplary. The method of the present disclosure is not limited to the steps and sequence shown above. The base station and user equipment shown above may include more modules, for example, modules that can be developed or will be developed in the future and can be used for the base station, MME, or UE, etc. The various identifiers shown above are merely exemplary and not restrictive, and the present disclosure is not limited to the specific information elements used as examples of these identifiers. Those skilled in the art may make many changes and modifications based on the teachings of the illustrated embodiments.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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 wireless link recovery method, comprising: The user equipment UE receives a conditional handover CHO configuration from the network side; Initiate the radio link control (RRC) re-establishment process and perform cell selection; When the selected suitable cell is a CHO candidate cell that includes a CHO configuration that adds and changes the CPAC configuration for conditional primary and secondary cells, if the execution conditions of the CPAC candidate cell in the CPAC configuration are met, the CHO configuration including the CPAC configuration corresponding to the CPAC candidate cell is applied to perform link recovery; otherwise, the CHO configuration including the CPAC configuration corresponding to the CPAC candidate cell with the best signal quality is applied to perform link recovery.

2. The wireless link recovery method according to claim 1, wherein: The CHO configuration received from the network side includes a traditional CHO configuration or a CHO configuration including a CPAC configuration; The traditional CHO configuration does not include SCG configuration or CPAC configuration; The CHO configuration including the CPAC configuration includes one or more configuration items, wherein one configuration item includes a CHO reconfiguration identifier, a CHO execution condition, a CPAC execution condition, and an RRC reconfiguration message including a primary cell group configuration and a secondary cell group configuration.

3. The wireless link recovery method according to claim 1 or 2, wherein: The UE receives first indication information from the network side, and when the first indication information exists or is set to TRUE, the UE applies the CHO configuration including the CPAC configuration to perform link recovery; The first indication information is used to indicate whether the UE can apply the CHO configuration including the CPAC configuration to achieve link recovery during the RRC re-establishment process.

4. The wireless link recovery method according to claim 2 or 3, wherein: When the first indication information does not exist or is set to FALSE, if the selected cell is a CHO candidate cell, the UE applies the traditional CHO configuration corresponding to the selected cell to perform link recovery.

5. The wireless link recovery method according to claim 3 or 4, wherein: The first indication information is included in the CHO configuration and configured to the UE; Only when the UE is configured with a CHO configuration including a CPAC configuration, the first Instructions are included in the CHO configuration.

6. The wireless link recovery method according to claim 1, wherein: If the selected cell corresponds to multiple CPAC candidate cells in the CHO configuration and the execution conditions are met; The UE applies the CHO configuration including the CPAC configuration corresponding to the CPAC candidate cell with the best signal quality among the multiple CPAC candidate cells that meet the execution conditions to perform link recovery.

7. The wireless link recovery method according to claim 1 or 4, wherein: The UE applying the CHO configuration means that the UE applies the configuration in the RRC reconfiguration message contained in the saved CHO configuration corresponding to the selected cell and performs corresponding operations.

8. A user equipment UE, comprising: processor; as well as A memory storing instructions; Wherein, when the instructions are executed by the processor, the wireless link recovery method according to any one of claims 1 to 7 is executed.

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