CN115589620A - Cell change execution method and user equipment - Google Patents

Abstract

The disclosure provides a cell change execution method and user equipment. The cell change execution method comprises the following steps: a conditional access (CHO) execution process on User Equipment (UE) is triggered; the UE judges whether a CPC process is in progress; if there is an ongoing CPC procedure, the UE stops the ongoing CPC procedure, and if there is no ongoing CPC procedure, the UE continues to perform the CHO procedure, wherein the CPC procedure is a conditional reconfiguration procedure for a secondary cell group, SCG.

Description

Cell change execution method and user equipment

Technical Field

The present disclosure relates to the field of wireless communication technologies, and in particular, to a method for performing a condition-based cell change procedure and a corresponding user equipment.

Background

The 3GPP RAN working group is currently conducting a release 17 research project (see 3GPP document RP-193249 (New WID on flame enhancements on Multi-Radio Dual-Connectivity)). One of the research objectives of this project is to implement a process of adding and changing Primary and Secondary cells (pscells) based on conditions in a Dual Connectivity (DC) scenario. More specifically, a condition-based PSCell change process in a PSCell change scenario between Inter-Secondary nodes (Inter-Secondary nodes) is implemented.

The present disclosure proposes a solution to the problem of how to implement condition-based PSCell addition or change in NR systems.

Disclosure of Invention

An object of the embodiments of the present disclosure is to propose a solution to the problem of how to implement condition-based PSCell addition or change in NR systems. More specifically, the present disclosure proposes a solution for the execution process of CPAC and CHO processes when the UE is configured with both Conditional HandOver (CHO) and Conditional PSCell Addition or Change (CPAC) based conditions in the NR system. The disclosed embodiments provide a CPAC and CHO process execution method executed in a user equipment and a corresponding user equipment.

According to a first aspect of the present disclosure, a cell change execution method is provided, including: a conditional access (CHO) execution process on User Equipment (UE) is triggered; the UE judges whether a CPC process is in progress; if there is an ongoing CPC procedure, the UE stops the ongoing CPC procedure, and if there is no ongoing CPC procedure, the UE continues to perform the CHO procedure, wherein the CPC procedure is a conditional reconfiguration procedure for a secondary cell group, SCG.

In the cell change performing method of the first aspect, when the UE stops the CPC procedure in progress, the UE may perform at least one of the following operations: operation 1: stopping a T304 timer for the SCG/primary and secondary cell PSCells; operation 2: resetting the media access control MAC of the SCG; operation 3: releasing dedicated random access resources provided in the rach-configdivided configuration for the SCG; and operation 4: releasing the conditional reconfiguration for SCG saved in varconditional reconfig; and operation 5: fallback to the SCG configuration used at the source secondary base station SN/SCG.

In the cell change performing method of the first aspect, the UE may continue to perform the CHO procedure after the UE stops the ongoing CPC procedure.

In the cell change execution method according to the first aspect, the presence of an ongoing CPC procedure indicates that the T304 timer for the SCG/PSCell is running and the execution of the RRC reconfiguration is initiated due to the conditional reconfiguration of the SCG/PSCell, and the absence of an ongoing CPC procedure indicates that the T304 timer for the SCG/PSCell is not running or that the execution of the RRC reconfiguration is not initiated due to the conditional reconfiguration of the SCG/PSCell.

According to a second aspect of the present disclosure, a cell change execution method is provided, including: a conditional access CHO process on user equipment UE is triggered; the UE judges whether a CPC process is in progress or not; if the CPC process is in progress, the UE continues to execute the CPC process, and after the CPC process is finished, the CHO execution process is executed; and when generating an RRC reconfiguration complete message in a CHO execution process or before transmitting the RRC reconfiguration complete message, the UE including an indication in the RRC reconfiguration complete message, the indication being for informing a CHO target cell that the UE has undergone a CPC procedure just before executing the CHO procedure, wherein the CPC procedure is a conditional reconfiguration procedure for a secondary cell group, SCG.

In the cell change execution method according to the second aspect, the presence of the ongoing CPC procedure indicates that the T304 timer for the SCG/PSCell is running, and the execution procedure of the RRC reconfiguration is initiated due to a conditional reconfiguration of the SCG/PSCell.

In the cell change performing method of the second aspect, the UE may suspend SCG transmission after the CPC procedure is completed.

In the cell change execution method according to the second aspect, the UE may apply the SCG configuration and resume SCG transmission after receiving the RRC reconfiguration message that includes the SCG configuration in the first CHO target cell.

According to a third aspect of the present disclosure, there is provided a user equipment comprising: a processor; and a memory storing instructions; wherein the instructions, when executed by the processor, perform the cell change execution method according to context.

Drawings

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

fig. 1 is a diagram illustrating a general handover procedure.

Fig. 2 is a flowchart showing a cell change execution method in embodiment 1 of the present disclosure.

Fig. 3 is a block diagram representing a user equipment UE to which the present disclosure relates.

In the drawings, the same or similar structures are identified by the same or similar reference numerals.

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, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the disclosure.

In the present disclosure, the terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or.

In this specification, the various embodiments described below which are used to describe the principles of the present disclosure are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the present disclosure as defined by the claims and their equivalents. The following description includes various specific details to aid understanding, but such details are to be regarded as illustrative only. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the present disclosure. Moreover, descriptions of well-known functions and constructions are omitted for clarity and conciseness. Moreover, throughout the drawings, the same reference numerals are used for similar functions and operations.

Hereinafter, a Long Term Evolution (LTE)/NR mobile communication system and its subsequent Evolution are taken as an example application environment, and a plurality of embodiments according to the present disclosure are specifically described. However, it is to be noted that the present disclosure is not limited to the following embodiments, but is applicable to more other wireless communication systems. Unless otherwise specified, the concepts of cell and base station may be interchanged in this disclosure; the LTE system is also used to refer to the LTE system of 5G and beyond (e.g. referred to as the LTE system, or the LTE system that can be connected to the 5G core network), and LTE may be replaced by Evolved Universal Terrestrial Radio Access (E-UTRA) or Evolved Universal Terrestrial Radio Access network E-UTRAN. The cell change according to the present disclosure includes handover and PSCell change. The handover refers to a change of a Primary Cell (PCell), where the change of the Primary Cell including inter-cells also includes a change of a Primary Cell in the Cell, that is, a Primary Cell of the UE is changed from a source Primary Cell to a target Primary Cell, where the source Primary Cell and the target Primary Cell may be the same Cell or different cells, and in this process, a secret key or a security algorithm for access stratum security may be updated or not. The source primary cell refers to a cell serving the UE, which is connected before the handover process is initiated, that is, a cell transmitting a Radio Resource Control (RRC) message including a handover command to the UE. The target primary cell refers to a cell serving the UE and connected to the UE after the handover procedure is successfully completed, a cell indicated by a target cell identifier included in the handover command, or a cell that performs downlink synchronization and random access in the handover procedure. Similarly, a PSCell change refers to a change in PSCell, and may be a cell change within one secondary base station SN or a cell change across SNs. The PSCell before the cell change is referred to as a source PSCell, and the PSCell after the cell change is a target PSCell. In the present disclosure, a Cell may also be understood as a base station, or called beam (beam), transmission point (TRP), a Cell Group (CG). For example, the source primary cell may be referred to as a source base station, a source beam, a source TRP, or a source primary cell group; the target master cell can also be called a target base station, or a target light beam, a target transmission point and a target master cell group; the source PSCell may be referred to as a source secondary base station or a source secondary cell group; the target PSCell may be referred to as a target secondary base station or a target secondary cell group. The handover command or PSCell change command according to the present disclosure is an RRC reconfiguration message including a synchronization reconfiguration (reconfiguration with sync) information element in the NR system. Further, the RRC reconfiguration message including a synchronization reconfiguration (reconfiguration with sync) information element for the primary cell group MCG is used for handover of the primary cell PCell, and the synchronization reconfiguration (reconfiguration with sync) information element included in the primary-secondary cell group SCG configuration is used for addition or change of the PSCell. The handover may also be referred to as a synchronous reconfiguration of the MCG and the PSCell addition or change may also be referred to as a synchronous reconfiguration of the SCG. For convenience of description, the RRC reconfiguration message and the RRC connection reconfiguration message are equivalent in this disclosure; similarly, the response message RRC reconfiguration complete message is equivalent to the RRC connection reconfiguration complete message. The synchronization reconfiguration is equivalent to an RRC message containing the synchronization reconfiguration, and refers to an RRC message or a configuration in the RRC message that triggers the UE to perform handover. Cancellation, release, deletion, cleanup, and the like may be substituted. Execution, use, and application are alternatives. Configuration and reconfiguration may be alternative. Monitoring (monitor) and detection (detect) may be replaced. For ease of description, PSCell changes include both PSCell changes and PSCell additions.

The following describes processes or concepts in the prior art to which the present disclosure relates.

Handover configuration in NR system:

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 configurations (see section 6.2.2 in 3GPP technical standard protocol 38.331):

-measurement configuration (measconfig information element): for configuring intra-frequency, inter-frequency and inter-radio access technology measurements performed by the UE. Such as measurement object configuration, measurement reporting configuration, measurement gap (gap) configuration, etc.

-a cell group configuration (cellGroupConfig information element) for configuring the master cell group or the secondary cell group. The method includes Radio Link Control (RLC) bearer configuration (RLC-bearer toaddmodlist information element and RLC-bearer toreselist information element) corresponding to a data Radio bearer/a signaling Radio bearer, medium Access Control (MAC) configuration (MAC-cell group pconfig information element), physical layer configuration, secondary cell addition/modification/release configuration, special cell (SpCell) configuration, and the like. The SpCell configuration includes a cell index number, handover information (serving cell information element), radio Link failure related timer and constant configuration, radio Link Monitoring (RLM) configuration, special cell dedicated configuration, and the like. The reconfigurationwitthsync information element is similar to the mobile control information in the LTE system, and includes handover related information to realize mobility, which includes serving cell configuration public information, cell radio network temporary identity C-RNTI of the UE in the target cell, handover process monitoring timer T304 configuration, random access dedicated configuration for random access process to the target cell, and the like.

-non access stratum specific information (dedicatedinfonsulst information element).

-Radio Bearer configuration (radioconfiguration information element) for configuring a service Data Application Protocol layer (SDAP) and a Packet Data Convergence Protocol layer (PDCP) of a Data Radio Bearer (DRB) and/or a Signalling Radio Bearer (SRB).

Master key update configuration (masterKeyupdate information element).

Dual Connectivity (DC):

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 at the two base stations. The Radio Access between the two base stations and the UE may be of the same or different Standards (RATs), such as NR, or one NR, and one LTE is also called Evolved Universal Terrestrial Radio Access (E-UTRA). One of the two base stations is called a Master Node (MN) or MgNB, meNB, and a Group of serving cells under the Master base station is called a Master Cell Group (MCG); the other is called a Secondary Node (SN) or SgNB, seNB, and the serving Cell Group under the Secondary Node is called a Secondary Cell Group (SCG). The MCG comprises one Primary Cell (PCell) and optionally one or more Secondary cells (scells). The PCell works on the main frequency, and the UE executes an initial connection establishment process or a connection reestablishment process through the main frequency. The SCG contains one PSCell and optionally one or more scells. The PSCell refers to an SCG cell in which the UE performs random access when performing a synchronization reconfiguration procedure or an SCG addition procedure. PCell and PSCell are also collectively referred to as special cell SpCell.

Handover procedure in NR system:

the mobility of the connected user is mainly achieved through a handover procedure, i.e. a procedure in which the UE in the RRC connected state changes a serving cell (primary cell). Fig. 1 is a diagram illustrating a general handover procedure. As shown in fig. 1, a general handover procedure includes the following stages: stage 1: and (5) a measuring stage. And the UE measures the radio link corresponding to the serving cell or the adjacent cell based on the configured measurement configuration, and when the configured measurement reporting condition is met, the UE sends a measurement report to the base station. And (2) stage: and a switching preparation phase. The base station determines to trigger the switching for the UE according to the received measurement report and other factors such as base station load, and the source base station and the target base station acquire a switching command configured by the target base station through a switching preparation process. And (3) stage: and switching the execution phase. The source base station sends the switching command to the UE, and the UE receiving the switching command immediately applies the configuration of the switching command to execute switching. The UE detects the switching process through a timer T304, and when the switching process is initiated, the UE starts the T304 timer; when the handover procedure is completed, the UE stops the timer T304; when T304 times out, the UE considers the handover as failed. The handover procedure described above is also applicable to the PSCell change procedure.

Unlike the conventional handover process in which the UE immediately performs handover after receiving a handover command in stage 3, the NR system also supports conditional handover CHO, also called conditional reconfiguration. In the conditional handover, a relatively conservative measurement report threshold is set, so that the base station obtains the measurement result in advance, and performs handover preparation in advance according to the measurement result and the selected target base station, so that the base station can issue a handover command containing a handover candidate cell and a handover execution condition to the UE in advance before a real handover condition (relative to the conservative measurement report threshold) is met, wherein the handover command carries a condition for the UE to perform handover. After receiving the conditional handover command, the UE does not immediately perform handover, but stores 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 satisfied. And only when the configured switching execution condition is monitored to be met, the UE starts to execute the stored switching command and accesses to the target cell. The UE may be configured with multiple conditional handover candidate cells at the same time, and if the multiple conditional handover candidate cells simultaneously satisfy the handover execution condition, the UE selects one candidate cell among the multiple conditional handover candidate cells as a final target cell for conditional handover, and executes handover to the candidate cell. In summary, conditional handover refers to a handover procedure that is performed only when one or more handover execution conditions configured are satisfied. Since the handover command is included in the RRC reconfiguration message, the conditional handover is also called conditional reconfiguration (conditional reconfiguration).

PSCell Change procedure in NR System

The PSCell change procedure in NR systems is triggered by the UE to perform through an RRC reconfiguration message for SCG containing a synchronization reconfiguration information element. The PSCell change procedure may be initiated by the MN or by the SN. When a Signaling Radio Bearer (SRB) 3 is configured, the SN may autonomously initiate a PSCell change process without participation of the MN, and at this time, the SN sends a PSCell change command for SCG to the UE on the SRB 3. In general, PSCell changes initiated autonomously by SN of SRB3 are Intra-SN, i.e., PSCell changes within the same secondary base station. When SRB3 is not configured, PSCell change commands are sent to UE on SRB1 by PSCell change processes initiated by SN or MN, including intra-SN or inter-SN PSCell changes. The RRC reconfiguration message for the PSCell change command of the SN is contained in an NR-SecondaryCellGroup config information element (when the E-UTRAN is MN) or an mrdc-SecondaryCellGroup information element (when the NR is MN) of its outer RRC message. The outer layer message is typically an RRC (connection) reconfiguration message or a dlinformation transfermrdc message. The UE receiving the PSCell change command executes the change process of the PSCell, starts a timer T304 for monitoring the process, starts downlink synchronization to the target PSCell, applies a configuration including an RRC reconfiguration message for synchronous reconfiguration of the SCG, and sends an RRC reconfiguration complete message to the network side. According to the outer layer message of the received PSCell change command, the RRC reconfiguration complete message may also be embedded in an outer layer RRC message, such as an RRC (connection) reconfiguration complete message or a ULInformationTransferMRDC message.

After the condition reconfiguration is introduced into the NR system, the condition reconfiguration is supported to be used for adding or changing the PSCell. Similar to the conditional handover CHO, the UE being configured with a conditional reconfiguration (also called CPAC configuration or CPC configuration) for SCG means that the conditional reconfiguration including PSCell candidate cells and execution conditions is issued to the UE. After receiving the condition reconfiguration, the UE does not immediately perform addition or change of the PSCell candidate cells included therein, but stores the received condition reconfiguration, and starts to monitor the link quality of the source cell or the link quality of the target candidate cell according to the execution condition carried therein to evaluate whether the execution condition is satisfied. And only when the configured execution condition is monitored to be met, the UE starts to execute SCG configuration in the stored condition reconfiguration and accesses the selected PSCell candidate cell. As with CHO, the UE may be configured with multiple PSCell candidate cells at the same time, and if the multiple candidate cells simultaneously satisfy the execution condition, the UE selects one candidate cell among them as the final target PSCell cell and synchronizes to the candidate cell.

Conditional reconfiguration

As previously described, the conditional reconfiguration may be applied to either the MCG or the SCG. When the conditional reconfiguration (conditional reconfiguration) is a conditional reconfiguration for MCG/PCell, it is also called conditional handover CHO; on the other hand, when the condition reconfiguration is a condition reconfiguration for SCG/PSCell, it is called that the condition PSCell changes the CPC or that the condition PSCell adds or changes the CPAC. In the NR system, after receiving an RRC reconfiguration message including a conditional reconfiguration (conditional reconfiguration information element that includes a conditional reconfiguration candidate cell list (contenfigugtoadmodlist information element)), the UE stores a configuration corresponding to the conditional reconfiguration candidate cell in a UE variable varconfigurationreconfiguration, which includes a plurality of items. Each item is identified by a conditional reconfiguration identity (condrecconfigid), containing the execution condition (condExecutionCond) and the RRC configuration (condrrcconfig) of the candidate cell. The cell identified by the cell identification in the serving cell common configuration (serving cell configcommon information element) in the synchronization reconfiguration (reconfiguration within sync information element) in the RRC configuration of the candidate cell corresponds to a conditional reconfiguration candidate cell. And the UE performs condition reconfiguration evaluation on each condition reconfiguration candidate cell according to the execution condition. The execution condition may include one or two measurement identifiers (measID), and only when the measurement events (e.g., condEventA3 or condEventA5 included in the CondTriggerConfig information element) corresponding to all the measurement identifiers included in the execution condition are satisfied, the UE considers the corresponding candidate cell as a trigger cell and initiates a condition reconfiguration execution process. In the conditional reconfiguration execution process, the UE applies the stored RRC configuration (condrrcconfig) corresponding to the cell to the selected trigger cell, and executes a cell change operation, such as starting a timer T304, performing downlink synchronization to the selected cell, initiating a random access procedure to the selected cell for uplink synchronization, and sending an RRC reconfiguration complete message to the selected cell (see section 5.3.5.3 of 3GPP protocol specification document TS38.331, which is not described herein). For convenience of description, the conditional reconfiguration for SCG and CPC/CPAC may be replaced.

In the NR system of release 16, although both the conditional reconfiguration of CHO and the conditional reconfiguration of CPC are supported, in order to reduce the complexity of the system and the UE, it is not supported that both CHO and CPC are configured for one UE. That is, in the release 16 system, only CHO or CPC configuration is supported on the UE. In the current ongoing conditional reconfiguration discussion of release 17, considering that the scenarios applied to the CHO and the CPC are different, the former is used to improve the mobility performance of the PCell, and the latter is used to improve the mobility performance of the PSCell, and it is a considerable problem to configure the CHO and the CPC for one UE. In a scenario where the UE is configured with the condition reconfiguration of the CHO and the CPC at the same time, the UE needs to perform the CHO and CPC condition reconfiguration evaluation (conditional reconfiguration evaluation) at the same time. If the execution condition of CPC is satisfied first, that is, when determining a trigger cell according to the CPC condition reconfiguration evaluation, the CHO condition reconfiguration evaluation does not satisfy the execution condition of the candidate cell, and considering that the importance of the mobility performance of PCell is higher than that of PSCell, a reasonable way is to make the UE perform the CPC procedure to the selected trigger cell, and continue to perform the CHO condition reconfiguration evaluation during the CPC procedure. There is a case that the UE needs to perform the CHO conditional reconfiguration procedure when the CHO execution condition is satisfied in the CHO conditional reconfiguration evaluation procedure during the ongoing CPC procedure and a triggering cell is determined. But how to handle the ongoing CPC procedure becomes a concern of the present disclosure.

The embodiments described below give solutions to the above-mentioned problems, and some concepts or definitions may be common among the embodiments unless otherwise specified.

Example 1

This embodiment presents a cell change method performed on a UE. For the foregoing scenario, when a CHO execution process is triggered on the UE and there is an ongoing CPC execution process on the UE at this time, the UE stops the ongoing CPC execution process and then executes the CHO execution process, so as to avoid executing two RRC processes at the same time, thereby avoiding a problem of configuration confusion on the UE caused by the two RRC processes being executed at the same time on the UE.

As an example, fig. 2 is a flowchart illustrating a cell change execution method according to embodiment 1 of the present disclosure. As shown in fig. 2, as an implementation manner of embodiment 1, the method includes the following steps:

step 1: and when the UE initiates the CHO executing process, judging whether an ongoing CPC process exists, if so, executing the step 2 by the UE, otherwise, executing the step 3 by the UE if no ongoing CPC process exists.

The UE initiates a CHO execution process, or the UE applies the saved conditional reconfiguration condrrcreeconfig to the selected candidate cell for CHO, and executes the conditional reconfiguration execution operation (see section 5.3.5.3 of 3GPP protocol specification 38.331, which is not described herein). The UE may also perform the above determination during the process of performing the conditional switch, for example, when performing the conditional reconfiguration execution operation.

The there is an ongoing CPC procedure that means that a T304 timer for the SCG/PSCell is running and the RRC reconfiguration execution procedure is initiated due to a conditional reconfiguration of the SCG/PSCell. The no ongoing CPC procedure means that a T304 timer for the SCG/PSCell is not running or the execution procedure of the RRC reconfiguration is not initiated due to a conditional reconfiguration of the SCG/PSCell.

Step 2: the UE stops the ongoing CPC procedure. The UE stops the ongoing CPC procedure by performing one or more of the following:

operation 1: stopping the T304 timer for the SCG/PSCell;

operation 2: resetting the MAC of the SCG;

operation 3: the dedicated random access resource (e.g., random access preamble) provided in the rach-ConfigDedicated configuration is released. The rach-ConfigDedicated configuration is included in the conditional reconfiguration for SCG corresponding to the CPC procedure, for the CPC procedure;

and operation 4: releasing the conditional reconfiguration for SCG saved in varconditional reconfig;

operation 5: rollback to the SCG configuration used at the source SN/SCG. I.e. the SCG configuration on the UE is rolled back to the SCG configuration before the CPC procedure is performed;

operation 6: and reconstructing the RLC entity corresponding to the SCG associated bearer.

After stopping the ongoing CPC procedure, the UE performs step 3.

The present embodiment does not limit the execution sequence when the UE performs more than one of the above operations.

And step 3: the UE continues to perform the CHO procedure.

The stopping of the ongoing CPC procedure may also be referred to as abandoning (abort) the ongoing CPC procedure.

Example 2

This embodiment presents another cell change method, performed on the UE. For the foregoing scenario, when a CHO execution process is triggered on the UE and there is an ongoing CPC execution process on the UE at this time, the UE continues to execute the CPC execution process, and after the CPC execution process is completed, the CHO execution process is executed again to avoid a configuration confusion process caused by executing two related RRC processes on the UE at the same time.

In this embodiment, the UE performs a CHO execution procedure and sends an RRC reconfiguration complete message to the target cell. When generating RRC reconfiguration complete message or before sending RRC reconfiguration complete message, UE judges whether there is a CPC process in progress when the CHO executing process is initiated, if yes, UE includes an indication in the RRC reconfiguration complete message. The indication is used to inform the CHO target cell that the UE has undergone one CPC procedure just before performing the CHO procedure. I.e. the execution of CHO immediately follows the CPC process. Therefore, whether an ongoing CPC process is initiated by the CHO executing process may also be described as whether a CPC process that has just been completed before the CHO executing process is executed.

The there is an ongoing CPC procedure that means that a T304 timer for the SCG/PSCell is running and the RRC reconfiguration execution procedure is initiated due to a conditional reconfiguration of the SCG/PSCell. The no ongoing CPC procedure means that a T304 timer for the SCG/PSCell is not running or the execution procedure of the RRC reconfiguration is not initiated due to a conditional reconfiguration of the SCG/PSCell.

Based on the indication in the received RRC reconfiguration complete message, the CHO target cell knows that the UE has just completed a CPC procedure, at which point the UE context (SCG configuration) saved by the CHO target cell is not the latest UE configuration. The CHO target cell may obtain the latest UE context from the source cell by initiating a UE context acquisition procedure between the source cell and the CHO target cell (SCG configuration). Preferably, the UE CONTEXT acquisition procedure refers to a RETRIEVE UE CONTEXT procedure.

Considering that the SCG configuration of the UE after the CPC procedure is performed may be inconsistent with the SCG configuration of the UE stored in the CHO target cell, the UE may suspend the transmission of SCG or deactivate the SCG after the CPC procedure is completed, so as to suspend the transmission and reception of SCG. Optionally, the UE suspends SCG transmission or deactivates the SCG after the CHO procedure is completed. Optionally, when performing the CHO procedure, the UE does not apply the SCG configuration in the RRC reconfiguration corresponding to the target cell or does not perform the operation related to the SCG configuration. After the CHO is successfully completed, after the UE successfully receives the first RRC reconfiguration message containing the SCG configuration of the CHO target cell, the UE applies the SCG configuration and recovers SCG transmission or activates SCG. The SCG transmission refers to Data Radio Bearer (DRB) or Signaling Radio Bearer (SRB) transmission associated with the SCG. The CPC process and CPC execution process may be replaced, and the CHO process and CHO execution process may be replaced.

Preferably, the SCG configuration refers to an RRC configuration included in mrdc-SecondaryCellGroup or mrdc-SecondaryCellGroup pconfig. The UE completing the CPC procedure means that the MAC successfully completes the random access procedure triggered by the synchronization reconfiguration of the SCG. It may also refer to CPC procedure failure end, i.e. PSCell/SCG synchronization reconfiguration failure due to T304 timeout for SCG. The UE completing the CHO procedure means that the MAC successfully completes the random access procedure triggered by the synchronization reconfiguration of the MCG.

Alternatively, if the CPC procedure fails (T304 of SCG is timed out), considering that there is a triggered CHO procedure at this time, the UE does not perform the operation of initiating the SCG failure information procedure, i.e. does not report the failure of the CPC procedure to the network side.

In this embodiment, when a CHO execution procedure is triggered on the UE and there is an ongoing CPC execution procedure on the UE, the UE continues to execute the CPC execution procedure, which may be regarded as the triggered CHO procedure being suspended; after the CPC procedure is completed, the CHO execution procedure is performed again, which may be considered as a triggered CHO procedure being resumed. Alternatively, the UE may record whether there is a CHO process that is suspended by setting a variable, such as "TRUE" when the CHO process is suspended and "FALSE" when the CHO process is resumed or not suspended. The UE determines from the recorded variables whether there is a pending triggered CHO procedure. If the UE determines that the variable value is "TRUE" after the CPC process is executed, the UE resumes the suspended CHO process, continues to execute the CHO process, and sets the variable value to "FALSE".

Example 3

This embodiment explains the user equipment UE of the present disclosure. Fig. 3 is a block diagram showing a user equipment UE according to the present invention. As shown in fig. 3, the user equipment UE30 includes a processor 301 and a memory 302. The processor 301 may include, for example, a microprocessor, a microcontroller, an embedded processor, or the like. The memory 302 may include, for example, volatile memory (e.g., random access memory RAM), a Hard Disk Drive (HDD), non-volatile memory (e.g., flash memory), or other memory, among others. The memory 302 has stored thereon program instructions. Which when executed by the processor 301 may perform the above-described cell change performing method described in detail in the present invention.

The method of the present disclosure and the related apparatus have been described above in connection with preferred embodiments. Those skilled in the art will appreciate that the methods illustrated above are exemplary only. The methods of the present disclosure are not limited to the steps or sequences shown above. The base station and the user equipment shown above may comprise further modules, for example, modules that may be developed or developed in the future, which may be available for the base station, MME, or UE, etc. The various identifiers shown above are merely exemplary and not limiting, and the present disclosure is not limited to the specific information elements that are examples of these identifiers. Many variations and modifications may occur to those skilled in the art in light of the teachings of the illustrated embodiments.

The program running on the apparatus according to the present disclosure may be a program that causes a computer to realize 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 nonvolatile memory (such as a flash memory), or other memory system.

A program for implementing the functions of the embodiments of the present disclosure may be recorded on a computer-readable recording medium. The corresponding functions can be realized by causing a computer system to read the programs recorded on the recording medium and execute the programs. The term "computer system" as used herein may be a computer system embedded in the device and may include an operating system or hardware (e.g., peripheral devices). The "computer-readable recording medium" may be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a recording medium that stores a program for short-term dynamics, or any other recording medium that is readable by a computer.

Various features or functional blocks of the devices used in the above-described embodiments may be implemented or performed by circuitry (e.g., a single or multiple chip integrated circuits). Circuitry designed to perform the functions described herein 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 device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The circuit may be a digital circuit or an analog circuit. Where new integrated circuit technology has emerged as a replacement for existing integrated circuits due to advances in semiconductor technology, one or more embodiments of the present disclosure may also be implemented using such new integrated circuit technology.

Further, the present disclosure is not limited to the above-described embodiments. While various examples of the embodiments have been described, the present disclosure is not so limited. Fixed or non-mobile electronic devices installed indoors or outdoors may be used as terminal devices or communication devices, such as AV devices, kitchen devices, cleaning devices, air conditioners, office devices, vending machines, and other home appliances.

As above, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. However, the specific configuration is not limited to the above embodiment, and the present disclosure also includes any design modification without departing from the gist 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 technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. Further, components having the same effects described in the above embodiments may be substituted for each other.

Claims (9)

1. A cell change execution method includes:

a conditional access (CHO) execution process on User Equipment (UE) is triggered;

the UE judges whether a CPC process is in progress;

if there is an ongoing CPC procedure, the UE stops the ongoing CPC procedure,

if there is no ongoing CPC procedure, the UE continues to perform the CHO procedure,

wherein the CPC procedure is a conditional reconfiguration procedure for a secondary cell group, SCG.

2. The cell change performing method according to claim 1,

while the UE stops the CPC procedure in progress, the UE performs at least one of:

operation 1: stopping a T304 timer for the SCG/primary and secondary cell PSCells;

operation 2: resetting the media access control MAC of the SCG;

operation 3: releasing dedicated random access resources provided in the rach-ConfigDedicated configuration for the SCG;

and operation 4: releasing the conditional reconfiguration for SCG saved in varconditional reconfig; and

operation 5: fallback to the SCG configuration used at the source secondary base station SN/SCG.

3. The cell change execution method according to claim 1,

after the UE stops the ongoing CPC procedure, the UE continues to perform the CHO procedure.

4. The cell change execution method according to claim 1,

the ongoing CPC procedure indicates that the T304 timer for SCG/PSCell is running and the execution procedure of RRC reconfiguration is initiated due to conditional reconfiguration of SCG/PSCell,

the no-ongoing CPC procedure indicates that the T304 timer for the SCG/PSCell is not running, or that the execution procedure of the RRC reconfiguration is not initiated due to a conditional reconfiguration of the SCG/PSCell.

5. A cell change execution method includes:

a conditional access (CHO) process on User Equipment (UE) is triggered;

the UE judges whether a CPC process is in progress;

if the CPC process is in progress, the UE continues to execute the CPC process, and after the CPC process is finished, the CHO execution process is executed; and

when generating an RRC reconfiguration complete message in a CHO execution process or before transmitting the RRC reconfiguration complete message, the UE including an indication in the RRC reconfiguration complete message, the indication being used for informing a CHO target cell that the UE has undergone a CPC process just before executing the CHO process,

wherein the CPC procedure is a conditional reconfiguration procedure for a secondary cell group, SCG.

6. The cell change execution method according to claim 5,

the there-ongoing CPC procedure indicates that the T304 timer for the SCG/PSCell is running and the execution procedure of the RRC reconfiguration is initiated due to a conditional reconfiguration of the SCG/PSCell.

7. The cell change execution method according to claim 5,

the UE suspends SCG transmission after the CPC process is completed.

8. The cell change performing method according to claim 5 or 7,

and after receiving the first RRC reconfiguration message containing the SCG configuration of the CHO target cell, the UE applies the SCG configuration and recovers SCG transmission.

9. A user equipment, UE, comprising:

a processor; and

a memory storing instructions;

wherein the instructions, when executed by the processor, perform the cell change performing method according to any one of claims 1 to 8.

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