WO2023280046A1

WO2023280046A1 - Cell change execution method and user equipment

Info

Publication number: WO2023280046A1
Application number: PCT/CN2022/102835
Authority: WO
Inventors: 常宁娟; 刘仁茂
Original assignee: 夏普株式会社; 常宁娟
Priority date: 2021-07-05
Filing date: 2022-06-30
Publication date: 2023-01-12
Also published as: CN115589620A

Abstract

The present disclosure provides a cell change execution method and a user equipment (UE). The cell change execution method comprises: a conditional handover (CHO) execution process is triggered on a UE; the UE determines whether there is an ongoing CPC process; if yes, the UE stops the ongoing CPC process; and if not, the UE continues to execute the CHO process, wherein the CPC process is a conditional reconfiguration process 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 more specifically, the present disclosure relates to a method for executing a condition-based cell change procedure and a corresponding user equipment.

Background technique

The 3GPP RAN working group is currently conducting a research project on version 17 (see 3GPP document RP-193249 (New WID on further enhancements on Multi-Radio Dual-Connectivity)). One of the research purposes of this project is to realize the condition-based addition and change process of Primary Secondary Cell Group Cell (PSCell) in the dual connectivity (Dual Connectivity, DC) scenario. More precisely, a condition-based PSCell change process in the PSCell change scenario between secondary base stations (Inter-Secondary Nodes) is implemented.

The present disclosure proposes a solution to the problem of how to implement condition-based addition or modification of PSCells in an NR system.

Contents of the invention

The purpose of the embodiments of the present disclosure is to provide a solution to the problem of how to implement condition-based addition or modification of a PSCell in an NR system. More specifically, the present disclosure is aimed at the execution of the CPAC and CHO procedures when the UE is simultaneously configured with Conditional HandOver (CHO) and condition-based PSCell Addition and Change (CPAC) in the NR system The process proposes a solution. Embodiments of the present disclosure provide a method for executing CPAC and CHO procedures executed in user equipment and corresponding user equipment.

According to the first aspect of the present disclosure, a cell change execution method is proposed, including: the conditional handover CHO execution process on the user equipment UE is triggered; the UE judges whether there is an ongoing CPC process; if there is an ongoing CPC process , the UE stops the ongoing CPC process, if there is no ongoing CPC process, the UE continues to perform the CHO process, wherein the CPC process is used for conditional reconfiguration of the secondary cell group SCG process.

In the method for performing cell change in the first aspect above, when the UE stops the ongoing CPC process, the UE may perform at least one of the following operations: Operation 1: Stop using the SCG/primary-secondary cell PSCell Operation 2: reset the medium access control MAC of the SCG; operation 3: release the dedicated random access resource provided in the rach-ConfigDedicated configuration for the SCG; operation 4: release the user stored in VarConditionalReconfig SCG-based conditional reconfiguration; and operation 5: fall back to the SCG configuration used at the source SeNB SN/SCG.

In the cell change execution method of the first aspect above, the UE may continue to execute the CHO process after the UE stops the ongoing CPC process.

In the cell change execution method of the first aspect above, the ongoing CPC process means that the T304 timer for SCG/PSCell is running, and the execution process of RRC reconfiguration is due to the conditional reconfiguration of SCG/PSCell Initiated, the no ongoing CPC process means that the T304 timer for the SCG/PSCell is not running, or the execution process of the RRC reconfiguration is not initiated due to the conditional reconfiguration of the SCG/PSCell.

According to the second aspect of the present disclosure, a cell change execution method is proposed, including: the conditional handover CHO process on the user equipment UE is triggered; the UE judges whether there is an ongoing CPC process; if there is an ongoing CPC process, The UE then continues to execute the CPC process, and then executes the CHO execution process after the CPC process is completed; and when the RRC reconfiguration complete message is generated during the CHO execution process or before the RRC reconfiguration complete message is sent, The configuration complete message includes an indication, and the indication is used to inform the CHO target cell that the UE has just gone through the CPC process before performing the CHO process, wherein the CPC process is a conditional reconfiguration process for the secondary cell group SCG.

In the cell change execution method of the second aspect above, the ongoing CPC process means that the T304 timer for SCG/PSCell is running, and the execution process of RRC reconfiguration is due to the conditional reconfiguration of SCG/PSCell Initiated.

In the cell change execution method of the second aspect above, the UE may suspend SCG transmission after completing the CPC process.

In the cell change execution method of the second aspect above, the UE may apply the SCG configuration and resume SCG transmission after receiving the first RRC reconfiguration message including the SCG configuration from the CHO target cell.

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

Description of drawings

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

FIG. 1 is a schematic diagram showing a general handover process.

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

FIG. 3 is a block diagram illustrating a user equipment UE involved in the present disclosure.

In the drawings, the same or similar structures are marked with the same or similar reference numerals.

detailed description

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

In this disclosure, the terms "include" and "comprising" and their derivatives mean to include but not to limit; the term "or" is inclusive, meaning and/or.

In this specification, the various embodiments described below to describe the principles of the present disclosure are illustrative 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 numerous specific details to aid in understanding, but these should be considered as examples 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 disclosure. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness. Also, the same reference numerals are used for similar functions and operations throughout the drawings.

The following takes the Long Term Evolution (Long Term Evolution, LTE)/NR mobile communication system and its subsequent evolution versions as an example application environment, and specifically describes multiple implementations according to the present disclosure. However, it should be pointed out that the present disclosure is not limited to the following embodiments, but is applicable to more other wireless communication systems. Unless otherwise specified, in this disclosure, the concept of a cell and a base station can be interchanged; the LTE system is also used to refer to 5G and subsequent LTE systems (such as eLTE systems, or LTE systems that can be connected to the 5G core network ), and LTE can be replaced by Evolved Universal Terrestrial Radio Access (E-UTRA) or Evolved Universal Terrestrial Radio Access Network (E-UTRAN). The cell change involved in the present disclosure includes handover and PSCell change. The handover refers to the change of the primary cell (Primary Cell, PCell), including the change of the primary cell between cells and the change of the primary cell within the cell, 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 The cell and the target primary cell may be the same cell or different cells. During this process, the secret key or security algorithm used for access layer security may also be updated or not updated accordingly. 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 (Radio Resource Control, RRC) message including a handover command to the UE. The target primary cell refers to the cell that the UE is connected to and serves the UE after the handover process is successfully completed, the cell indicated by the target cell identifier contained in the handover command, or the cell that performs downlink synchronization and random access during the handover process . Similarly, the PSCell change refers to the change of the PSCell, which may 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. In the present disclosure, a cell may also be understood as a base station, or called a beam (beam), a transmission point (Transmission point, TRP), or a cell group (Cell Group, CG). For example, the source primary cell can be called source base station, source beam, source TRP, and source primary cell group; the target primary cell can also be called target base station, or target beam, target transmission point, and target primary cell group; the source PSCell can be called The source SeNB or the source SeNB; the target PSCell may be called the target SeNB or the target SeNB. The handover command or PSCell change command described in the present disclosure is an RRC reconfiguration message including a synchronous reconfiguration (Reconfigurationwithsync) information element in the NR system. Furthermore, the RRC reconfiguration message containing the synchronization reconfiguration (Reconfigurationwithsync) information element used for the primary cell group MCG is used for the handover of the primary cell PCell, and includes the synchronization reconfiguration (Reconfigurationwithsync) information in the configuration of the primary secondary cell group SCG Elements are used to add or change PSCells. Therefore, handover can also be called synchronous reconfiguration of MCG, and addition or change of PSCell can also be called synchronous reconfiguration of SCG. For ease of description, the RRC reconfiguration message in this disclosure is equivalent to the RRC connection reconfiguration message; similarly, the response message RRC reconfiguration complete message is identical to the RRC connection reconfiguration complete message. The synchronous reconfiguration is equivalent to the RRC message including the synchronous reconfiguration, and refers to the RRC message or the configuration in the RRC message that triggers the handover of the UE. Cancel, Release, Delete, Empty and Clear etc. can be substituted. Execution, use, and application are interchangeable. Configuration and reconfiguration can be replaced. Monitor and detect are interchangeable. For ease of description, PSCell changes include both PSCell changes and PSCell additions.

The following describe processes or concepts in the prior art to which this disclosure pertains.

Switching configuration in NR system:

In the NR system, the RRC reconfiguration message used for the handover command carries the RRC configuration from the target base station, including but not limited to the following RRC configuration (for details, please refer to Section 6.2.2 of the 3GPP technical standard protocol 38.331):

- Measurement configuration (measconfig information element): used to configure intra-frequency, inter-frequency and inter-RAT measurements performed by the UE. Such as measurement object configuration, measurement reporting configuration, measurement gap (gap) configuration, etc.

- Cell group configuration (cellGroupConfig information element), used to configure a primary cell group or a secondary cell group. Including radio link control (Radio Link Control, RLC) bearer configuration (rlc-bearerToAddModList information element and rlc-bearerToreleaselist information element) corresponding to data radio bearer/signaling radio bearer, medium access control (Medium Access Control, MAC) configuration (MAC-cellgroupconfig information element), physical layer configuration, secondary cell addition/modification/release configuration, special cell (Special cell, SpCell) configuration, etc. Among them, the SpCell configuration includes cell index number, handover information (reconfigurationWithSync information element), radio link failure related timer and constant configuration, radio link monitoring (Radio Link Monitoring, RLM) configuration, special cell dedicated configuration, etc. Among them, the reconfigurationwithsync information element is similar to the mobile control information in the LTE system, including handover related information to achieve mobility, which includes serving cell configuration public information, UE's cell radio network temporary identifier C-RNTI in the target cell, and handover process monitoring timer T304 configuration, random access dedicated configuration for the random access process to the target cell, etc.

- Non-Access Stratum Dedicated Information (dedicatedInfoNASList information element).

- Radio bearer configuration (radiobearerConfig information element), used to configure the service data application protocol layer (Service Data Application Protocol, SDAP) of the data radio bearer (Data Radio Bearer, DRB) and/or signaling radio bearer (Signaling Radio Bearer, SRB) ) and Packet Data Convergence Protocol (PDCP).

- 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 in the two base stations. The wireless access between the two base stations and the UE can be the same or different standards (Radio Access Technology, RAT), such as NR, or one is NR, and the other is LTE, also known as the evolved universal terrestrial radio access ( Evolved Universal Terrestrial Radio Access, E-UTRA). Among the two base stations, one is called the master base station (Master Node, MN) or MgNB, MeNB, and the serving cell group under the master base station is called the master cell group (Master Cell Group, MCG); the other is called the secondary base station ( Secondary Node, SN) or SgNB, SeNB, the serving cell group under the secondary base station is called secondary cell group (Secondary Cell Group, SCG). The MCG includes a primary cell (Primary Cell, PCell) and optionally one or more secondary cells (Secondary Cell, SCell). The PCell works on the main frequency, and the UE performs the initial connection establishment process or the connection re-establishment process through the main frequency. SCG includes a PSCell and optionally one or more SCells. The PSCell refers to an SCG cell to which the UE performs random access when performing a synchronous reconfiguration procedure or an SCG addition procedure. The PCell and the PSCell are also collectively referred to as the special cell SpCell.

Handover process in NR system:

User mobility in the connected state is mainly realized through a handover process, which refers to a process in which a UE in the RRC connected state changes a serving cell (primary cell). FIG. 1 is a schematic diagram showing a general handover process. As shown in FIG. 1 , a general handover process includes the following phases: Phase 1: Measurement phase. Based on the configured measurement configuration, the UE measures the radio link corresponding to the serving cell or the neighboring cell, and 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 to trigger handover for the UE based on the received measurement report and other factors such as base station load, and the source base station and the target base station obtain the handover command configured by the target base station through the handover preparation process. Phase 3: Switch execution phase. The source base station sends the handover command to the UE, and the UE that receives the handover command immediately applies the configuration of the handover command to perform handover. The UE detects the handover process through a timer T304. When the handover process is initiated, the UE starts the T304 timer; when the handover process is completed, the UE stops the timer T304; when the T304 times out, the UE considers the handover failure. The above handover process is also applicable to the PSCell change process.

Different from the UE performing handover immediately after receiving the handover command in stage 3 of the general handover process, the NR system also supports conditional handover (CHO), also called 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 preparations in advance according to the measurement results and the selected target base station, so that the base station can perform handover under real handover conditions (relative to the conservative Before the measurement report threshold) is met, the handover command including the handover candidate cell and the handover execution condition is sent to the UE in advance, which carries the handover execution condition of the UE. After receiving the conditional handover command, the UE does not execute the handover immediately, but saves the configuration of the received handover command, and starts to monitor the link quality of the source cell or the link quality of the target cell according to the handover execution conditions carried in the handover command message. The road quality is used to evaluate whether the handover execution conditions are met. Only when it detects that the configured handover execution conditions are satisfied, 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 conditions at the same time, the UE selects one of the candidate cells as the final conditional handover target cell and performs handover to this cell. In a word, conditional switching refers to a switching process that is executed only when one or more configured switching execution conditions are met. Because the switching command is included in the RRC reconfiguration message, conditional switching is also called conditional reconfiguration (conditional reconfiguration).

PSCell change process in NR system

In the NR system, the PSCell change process is triggered by the UE through the RRC reconfiguration message containing the synchronous reconfiguration information element for the SCG. The PSCell change process can be initiated by the MN or by the SN. When Signaling Radio Bearer (SRB) 3 is configured, the SN can initiate the PSCell change process autonomously without the participation of the MN. At this time, the SN sends the PSCell change command for SCG to the UE on SRB3. Generally speaking, the PSCell change independently initiated by the SN of SRB3 is an Intra-SN, that is, a PSCell change within the same secondary base station. When SRB3 is not configured, no matter the PSCell change process initiated by the SN or the MN, the PSCell change command is sent to the UE on the SRB1, including intra-SN or inter-SN PSCell change. The RRC reconfiguration message for the PSCell change command of the SN is included in the nr-SecondaryCellGroupConfig information element (when the E-UTRAN is the MN) or the mrdc-SecondaryCellGroup information element (when the NR is the MN) of the outer RRC message. The outer message is generally an RRC (connection) reconfiguration message or a DLInformationTransferMRDC message. The UE receiving the PSCell change command executes the PSCell change process, starts the timer T304 for monitoring the process, starts downlink synchronization to the target PSCell, and applies the configuration including the RRC reconfiguration message for SCG synchronous reconfiguration , and send an RRC reconfiguration complete message to the network side. According to the received outer message of the PSCell change command, the RRC reconfiguration complete message may also be embedded in an outer RRC message, such as an RRC (connection) reconfiguration complete message or a ULInformationTransferMRDC message.

After conditional reconfiguration is introduced in the NR system, conditional reconfiguration is supported for adding or changing PSCells. Similar to conditional handover CHO, the UE is configured for SCG conditional reconfiguration (conditional reconfiguration) (also called CPAC configuration or CPC configuration) refers to sending the conditional reconfiguration including PSCell candidate cells and execution conditions to the UE. After receiving the conditional reconfiguration, the UE does not immediately add or change the PSCell candidate cells contained in it, but saves the received conditional reconfiguration, and starts monitoring the source cell according to the execution conditions carried in it. Link quality or the link quality of the target candidate cell to evaluate whether the execution conditions are met. Only when it detects that the configured execution condition is satisfied, 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 of the candidate cells as the final target PSCell cell and synchronizes to this cell.

conditional reconfiguration

As mentioned before, conditional reconfiguration can be applied to MCG or SCG. When the conditional reconfiguration is the conditional reconfiguration of MCG/PCell, it is also called conditional handover CHO; and when the conditional reconfiguration is the conditional reconfiguration of SCG/PSCell, it is called conditional PSCell change CPC Or conditional PSCell to add or change CPAC. In the NR system, after receiving the RRC reconfiguration message containing the conditional reconfiguration (ConditionalReconfiguration information element, which contains the conditional reconfiguration candidate cell list (condReconfigToAddModList information element)), the UE saves the configuration corresponding to the conditional reconfiguration candidate cell In the UE variable VarConditionalReconfig, which contains multiple items. Each item is identified by a conditional reconfiguration identifier (condReconfigId), including the execution condition (condExecutionCond) and the RRC configuration (condRRCReconfig) of the candidate cell. The cell identified by the cell identifier in the serving cell common configuration (servingCellConfigCommon information element) in the synchronous reconfiguration (reconfigurationWithSync information element) in the RRC configuration of the candidate cell corresponds to a conditional reconfiguration candidate cell. The UE performs conditional reconfiguration evaluation on each conditional reconfiguration candidate cell according to the execution condition. The execution condition may contain one or two measurement identifiers (measID). Only when the measurement events corresponding to all the measurement identifiers included in the execution condition (such as condEventA3 or CondEventA5 contained in the CondTriggerConfig information element) are satisfied, the UE considers that the The corresponding candidate cell is the trigger cell, and initiates a conditional reconfiguration execution process. During the execution of conditional reconfiguration, the UE applies the saved RRC configuration (condRRCReconfig) corresponding to the cell to the selected trigger cell, and performs cell change operations, such as starting timer T304, downlink synchronization to the selected cell, and sending The selected cell initiates a random access process for uplink synchronization, and sends an RRC reconfiguration completion message to the selected cell (see section 5.3.5.3 of 3GPP protocol specification document TS38.331 for details, which will not be described here). For the convenience of description, the conditional reconfiguration used for SCG and CPC/CPAC can be replaced.

In the release 16 NR system, although both CHO conditional reconfiguration and CPC conditional reconfiguration are supported, in order to reduce the complexity of the system and UE, simultaneous configuration of CHO and CPC for one UE is not supported. That is to say, in the version 16 system, it is only supported to configure only CHO or only CPC on the UE. In the ongoing discussion on conditional reconfiguration of Release 17, considering that CHO and CPC are applied in different scenarios, the former is used to improve the mobility performance of PCeIl, while the latter is used to improve the mobility performance of PSCell. Configuring CHO and CPC becomes an issue worthy of consideration. In the scenario where the UE is configured with CHO and CPC conditional reconfiguration at the same time, the UE needs to perform CHO and CPC conditional reconfiguration evaluation (conditional reconfiguration evaluation) at the same time. If the execution condition of the CPC is satisfied first, that is, when a triggering cell is determined according to the CPC conditional reconfiguration evaluation, the CHO conditional reconfiguration evaluation has not yet met the execution conditions of the candidate cell, considering that the mobility performance of the PCell is more important than the mobility performance of the PSCell, A reasonable way is to make the UE perform the CPC process to the selected trigger cell, and continue to perform CHO conditional reconfiguration evaluation during the process of performing the CPC. Then there is a situation that, during the ongoing CPC process, the UE needs to perform the CHO conditional reconfiguration process if the CHO execution condition is met during the CHO conditional reconfiguration evaluation process and a triggering cell is determined. But how to deal with the ongoing CPC process becomes a concern of this disclosure.

The following embodiments provide solutions based on the above problems, and some concepts or definitions are common among the embodiments unless otherwise specified.

Example 1

This embodiment provides a method for changing a cell performed on a UE. For the scenario described above, when the CHO execution process is triggered on the UE, and there is an ongoing CPC execution process on the UE, the UE stops the ongoing CPC execution process, and then executes the CHO execution process to avoid executing two CPC execution processes at the same time. The RRC process is used to avoid the problem of configuration confusion on the UE caused by two RRC processes being executed on the UE at the same time.

As an example, FIG. 2 is a flowchart showing a cell change execution method in Embodiment 1 of the present disclosure. As shown in Figure 2, as an implementation of Embodiment 1, the following steps are included:

Step 1: When the UE initiates the CHO execution process, it judges whether there is an ongoing CPC process. If there is an ongoing CPC process, the UE performs step 2. Otherwise, if there is no ongoing CPC process, the UE performs step 3.

The UE initiates the CHO execution process. It may also be that the UE applies the saved conditional reconfiguration condRRCReconfig to the selected candidate cell for CHO, and executes the conditional reconfiguration execution operation (see 5.3.5.3 of 3GPP protocol specification 38.331 chapter and will not be repeated here). It may also be that the UE performs the above judgment during the process of performing the conditional handover, such as when performing the conditional reconfiguration operation.

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

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

Operation 1: stop the T304 timer for SCG/PSCell;

Operation 2: Reset MAC of SCG;

Operation 3: release the dedicated random access resources provided in the rach-ConfigDedicated configuration (such as the random access preamble). The rach-ConfigDedicated configuration is included in the conditional reconfiguration for SCG corresponding to the CPC process, and is used for the CPC process;

Operation 4: Release the conditional reconfiguration for SCG stored in VarConditionalReconfig;

Operation 5: Revert back to the SCG configuration used at the source SN/SCG. That is, the SCG configuration on the UE falls back to the SCG configuration before the CPC process is executed;

Operation 6: Reestablish the RLC entity corresponding to the bearer associated with the SCG.

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

This embodiment does not limit the execution sequence when the UE executes more than one of the above operations.

Step 3: UE continues to execute the CHO process.

The aforementioned stopping of the ongoing CPC process may also be referred to as aborting (abort) the ongoing CPC process.

Example 2

This embodiment provides another cell change method, which is executed on the UE. For the scenario described above, when the 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 then executes the CHO execution process after the CPC process is completed. Avoid the configuration confusion process caused by executing two related RRC processes on the UE at the same time.

In this embodiment, the UE executes the CHO execution process, and sends an RRC reconfiguration complete message to the target cell. When generating the RRC reconfiguration complete message or before sending the RRC reconfiguration complete message, the UE judges whether there is an ongoing CPC process when the CHO execution procedure is initiated, and if so, the UE includes a in the RRC reconfiguration complete message instruct. The indication is used to inform the CHO target cell that the UE has just gone through a CPC process before performing the CHO process. That is, the execution of CHO is immediately after the CPC process. Therefore, whether there is an ongoing CPC process when the CHO execution process is initiated can also be described as whether there is a just-completed CPC process before the execution of the CHO execution process.

Based on the indication in the received RRC reconfiguration complete message, the CHO target cell learns that the UE has just completed a CPC process, and the UE context (SCG configuration) saved by the CHO target cell is no longer the latest UE configuration. The CHO target cell can obtain the latest UE context (SCG configuration) from the source cell through a UE context acquisition process between the initiator and the source cell. Preferably, the UE context acquisition process refers to the RETRIEVE UE CONTEXT process.

Considering that the UE's SCG configuration after the CPC process may be inconsistent with the UE's SCG configuration saved in the CHO target cell, optionally, the UE suspends the SCG transmission or deactivates it after completing the CPC process The SCG is used to suspend the sending and receiving of the SCG. Optionally, after completing the CHO process, the UE suspends SCG transmission or deactivates the SCG. Optionally, when performing the CHO process, the UE does not apply the SCG configuration in the RRC reconfiguration corresponding to the target cell or does not perform operations related to the SCG configuration. After the CHO is successfully completed, when the UE successfully receives the first RRC reconfiguration message including the SCG configuration from the CHO target cell, the UE applies the SCG configuration and resumes SCG transmission or activates the SCG. The SCG transmission refers to data radio bearer (Data Radio Bearer, DRB) or signaling radio bearer SRB transmission associated with the SCG. The CPC process and the CPC execution process can be replaced, and the CHO process and the CHO execution process can be replaced.

Preferably, the SCG configuration refers to the RRC configuration included in mrdc-SecondaryCellGroup or mrdc-SecondaryCellGroupConfig. The completion of the CPC procedure by the UE means that the MAC successfully completes the random access procedure triggered by the synchronous reconfiguration of the SCG. It may also refer to the failed end of the CPC process, that is, the PSCell/SCG synchronous reconfiguration failure caused by the timeout of T304 for the SCG. The completion of the CHO process by the UE means that the MAC successfully completes the random access process triggered by the synchronous reconfiguration of the MCG.

Optionally, if the CPC procedure fails (T304 of the SCG times 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, that is, does not report the CPC procedure to the network side fail.

In this embodiment, when the CHO execution process is triggered on the UE, and there is an ongoing CPC execution process on the UE, the UE continues to execute the CPC execution process. At this time, it can be seen that the triggered CHO process is suspended ; After the CPC process is completed, the CHO execution process is executed again, which can be regarded as the triggered CHO process being resumed. Optionally, a variable can be set on the UE to record whether there is a suspended CHO process. For example, when the CHO process is suspended, the UE sets this variable to "TRUE", and when the CHO process is resumed or not suspended , the UE sets this variable to "FALSE". The UE judges whether there is a pending CHO procedure that has been triggered according to the recorded variables. For example, after the execution of the CPC procedure ends, the UE judges that if the variable value is "TRUE", then the UE resumes the suspended CHO procedure, continues to execute the CHO procedure, and sets the variable value to "FALSE".

Example 3

This embodiment describes 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, and the like. The memory 302 may include, for example, a volatile memory (such as a random access memory RAM), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other memories. Memory 302 has program instructions stored thereon. When the instruction is executed by the processor 301, the above cell change execution method described in detail in the present invention can be executed.

The methods and related devices of the present disclosure have been described above in conjunction with preferred embodiments. Those skilled in the art can understand that the methods shown above are only exemplary. The methods of the present disclosure are not limited to the steps and order shown above. The base station and user equipment shown above may include more modules, for example, may also include modules that may be developed or developed in the future and may be used for the base station, MME, or UE, and the like. The various identifiers shown above are only exemplary rather than restrictive, and the present disclosure is not limited to specific information elements as examples of these identifiers. Numerous variations and modifications may be made by those skilled in the art in light of the teachings of the illustrated embodiments.

The program running on the device 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 volatile memory (such as random access memory RAM), hard disk drive (HDD), non-volatile memory (such as flash memory), or other memory systems.

A program for realizing the functions of the various embodiments of the present disclosure can be recorded on a computer-readable recording medium. The corresponding functions can be realized by causing a computer system to read programs recorded on the recording medium and execute the programs. The so-called "computer system" here may be a computer system embedded in the device, which may include an operating system or hardware (such as peripheral devices). The "computer-readable recording medium" may be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a recording medium in which a short-term dynamic storage program is stored, or any other recording medium readable by a computer.

Various features or functional modules of the devices used in the above-mentioned embodiments may be implemented or executed by circuits (for example, single-chip or multi-chip integrated circuits). Circuits designed to perform the functions described in this specification may include general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of the above. A general-purpose processor can be a microprocessor, or it can be any existing processor, controller, microcontroller, or state machine. The above-mentioned circuits may be digital circuits or analog circuits. Where new integrated circuit technologies have emerged to replace existing integrated circuits due to advances in semiconductor technology, one or more embodiments of the present disclosure may also be implemented using these new integrated circuit technologies.

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

As above, the embodiments of the present disclosure have been described in detail with reference to the drawings. However, the specific structure is not limited to the above embodiments, and the present disclosure also includes any design changes that do not deviate from the 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. In addition, components having the same effect described in the above embodiments can be substituted for each other.

Claims

A cell change execution method, comprising:

The conditional handover CHO execution process on the user equipment UE is triggered;

The UE determines whether there is an ongoing CPC process;

If there is an ongoing CPC process, the UE stops the ongoing CPC process,

If there is no ongoing CPC process, the UE continues to perform the CHO process,

Wherein, the CPC process is a conditional reconfiguration process for the secondary cell group SCG.
The cell change execution method according to claim 1, wherein,

When the UE stops the ongoing CPC process, the UE performs at least one of the following operations:

Operation 1: stop the T304 timer used for the SCG/PSCell;

Operation 2: Reset the medium access control MAC of the SCG;

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

Operation 4: Release the conditional reconfiguration for the SCG held in VarConditionalReconfig; and

Operation 5: Fall back to the SCG configuration used in the source secondary base station SN/SCG.
The cell change execution method according to claim 1, wherein,

After the UE stops the ongoing CPC process, the UE continues to execute the CHO process.
The cell change execution method according to claim 1, wherein,

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

The non-in progress CPC process means that the T304 timer for SCG/PSCell is not running, or the execution process of RRC reconfiguration is not initiated due to the conditional reconfiguration of SCG/PSCell.
A cell change execution method, comprising:

The conditional handover CHO process on the user equipment UE is triggered;

The UE determines whether there is an ongoing CPC process;

If there is an ongoing CPC process, the UE continues to execute the CPC process, and then executes the CHO execution process after the CPC process is completed; and

When the RRC reconfiguration complete message is generated during CHO execution or before the RRC reconfiguration complete message is sent, the UE includes an indication in the RRC reconfiguration complete message, and the indication is used to inform the CHO target cell that the UE is performing CHO The process has just gone through the CPC process before,

Wherein, the CPC process is a conditional reconfiguration process for the secondary cell group SCG.
The cell change execution method according to claim 5, wherein,

The ongoing CPC process indicates that the T304 timer for the SCG/PSCell is running, and the execution process of the RRC reconfiguration is initiated due to the conditional reconfiguration of the SCG/PSCell.
The cell change execution method according to claim 5, wherein,

The UE suspends SCG transmission after completing the CPC procedure.
The cell change execution method according to claim 5 or 7, wherein,

After receiving the first RRC reconfiguration message including SCG configuration from the CHO target cell, the UE applies the SCG configuration and resumes SCG transmission.
A user equipment UE, comprising:

processor; and

a memory storing instructions;

Wherein, the instruction executes the cell change execution method according to any one of claims 1-8 when executed by the processor.