WO2024082744A1

WO2024082744A1 - Methods and apparatuses for mro for subsequent cpac procedure

Info

Publication number: WO2024082744A1
Application number: PCT/CN2023/108744
Authority: WO
Inventors: Le Yan; Lianhai WU; Mingzeng Dai; Congchi ZHANG
Original assignee: Lenovo (Beijing) Limited
Priority date: 2023-07-21
Filing date: 2023-07-21
Publication date: 2024-04-25

Abstract

Various aspects of the present disclosure relate to methods and apparatuses for a MRO (Mobility Robustness Optimisation) mechanism for a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure. According to an embodiment of the present disclosure, a network node includes at least one memory and at least one processor coupled to the at least one memory and configured to cause the network node to: in case that a secondary cell group (SCG) failure occurs during a subsequent CPAC procedure, determine the SCG failure occurs in which one of the following: an initial conditional PSCell addition (CPA) of the subsequent CPAC procedure; an initial conditional PSCell change (CPC) of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure, wherein during the subsequent CPAC procedure, a user equipment (UE) doesn't release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.

Description

METHODS AND APPARATUSES FOR MRO FOR SUBSEQUENT CPAC PROCEDURE

TECHNICAL FIELD

The present disclosure relates to wireless communications, and more specifically to methods and apparatuses for a MRO (Mobility Robustness Optimisation) mechanism for a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure.

BACKGROUND

A wireless communications system may include one or multiple network communication devices, such as base stations, which may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE) , or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g. time resources (e.g. symbols, slots, subframes, frames, or the like) or frequency resources (e.g. subcarriers, carriers, or the like) . Additionally, the wireless communications system may support wireless communications across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) radio access technology, among other suitable radio access technologies beyond 5G (e.g. sixth generation (6G) ) .

SUMMARY

An article "a" before an element is unrestricted and understood to refer to "at least one" of those elements or "one or more" of those elements. The terms "a, " "at least one, " "one or more, " and "at least one of one or more" may be interchangeable. As used herein, including in the claims, "or" as used in a list of items (e.g. a list of items prefaced by a phrase such as "at least one of" or "one or more of" or "one or both of" ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase "based on" shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as "based on condition A" may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" shall be construed in the same manner as the phrase "based at least in part on. Further, as used herein, including in the claims, a "set" may include one or more elements.

Some implementations of the present disclosure provide a first network node. The first network node includes at least one memory; and at least one processor coupled to the at least one memory and configured to cause the first network node to: in case that a secondary cell group (SCG) failure occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure, determine the SCG failure occurs in which one of the following: an initial conditional PSCell addition (CPA) of the subsequent CPAC procedure; an initial conditional PSCell change (CPC) of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure, wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.

In some implementations of the first network node described herein, the at least one processor is configured to cause the first network node to: if a selected PSCell is not included in a first set of candidate target PSCells provided by the first network node, determine that wrong candidate target PSCell selection occurs at the first network node; if the selected PSCell is included in the first set of candidate target PSCells, but not included in a second set of candidate target PSCells selected by a second network node: transmit, to the second network node, information indicating that wrong candidate target PSCell selection occurs at the second network node; transmit SCG failure related information to the second network node; or transmit cell information of the selected PSCell to the second network node; and if the selected PSCell is included in the second set of candidate target PSCells: if the SCG failure occurs in the initial CPA, determine that one or more wrong CPA execution conditions are set for the initial CPA; if the SCG failure occurs in the initial CPC, determine that one or more wrong CPC execution conditions are set for the initial CPC; and if the SCG failure occurs in the subsequent CPC: transmit, to the second network node, information indicating that one or more wrong CPC execution conditions are set for the subsequent CPC; transmit the SCG failure related information to the second network node; or transmit the cell information of the selected PSCell to the second network node.

In some implementations of the first network node described herein, the first network node is one of the following: a master node (MN) ; and a secondary node (SN) managing a source PSCell in the initial CPA or the initial CPC, and the second network node is at least one candidate target secondary node (SN) .

In some implementations of the first network node described herein, the at least one processor is configured to cause the first network node to receive, from the UE or a third network node, information indicating that the SCG failure occurs in the initial CPA, information indicating that the SCG failure occurs in the initial CPC, or information indicating that the SCG failure occurs in the subsequent CPC.

In some implementations of the first network node described herein, the first network node is a secondary node (SN) , and the third network node is a master node (MN) .

In some implementations of the first network node described herein, the first network node is a master node (MN) , and to determine the SCG failure occurs in which one of the initial CPA, the initial CPC, and the subsequent CPC, the at least one processor is configured to cause the MN to: if none radio resource control (RRC) reconfiguration complete message is received before receiving SCG failure related information, determine that the SCG failure occurs in the initial CPA or the initial CPC; if one RRC reconfiguration complete message is received before receiving the SCG failure related information, determine time duration between receiving the one RRC reconfiguration complete message and the SCG failure related information; and if more than one RRC reconfiguration complete messages are received before receiving the SCG failure related information, determine that the SCG failure occurs in the subsequent CPC.

In some implementations of the MN described herein, after determining the time duration, the at least one processor is further configured to cause the MN to: if the time duration is shorter than or equal to a predefined threshold, determine that the SCG failure occurs in the initial CPA or the initial CPC; and if the time duration is longer than the predefined threshold, determine that the SCG failure occurs in the subsequent CPC.

In some implementations of the MN described herein, the at least one processor is further configured to cause the MN to transmit, to a secondary node (SN) managing a source PSCell in the initial CPA or the initial CPC, information indicating that the SCG failure occurs in the initial CPA, information indicating that the SCG failure occurs in the initial CPC, or information indicating that the SCG failure occurs in the subsequent CPC.

In some implementations of the first network node described herein, the at least one processor is configured to cause the first network node to determine that the SCG failure occurs during the subsequent CPAC procedure in response to detecting an event, wherein the event is one of the following: the UE performs a CPC execution from a first PSCell to a second PSCell successfully, but within a predefined limited time the UE performs a CPC execution from the second PSCell to a third PSCell successfully; the UE performs the CPC execution from the first PSCell to the second PSCell, but the CPC execution is not successful or the SCG failure occurs shortly after the CPC execution is successful, wherein the first PSCell is a suitable PSCell based on measurements reported from the UE; and the UE receives configuration information for the subsequent CPAC procedure, while the SCG failure occurs before one or more execution conditions of the initial CPC or the subsequent CPC are fulfilled.

In some implementations of the first network node described herein, the event occurs at least once in the subsequent CPAC procedure.

In some implementations of the first network node described herein, the first network node is a master node (MN) , and the at least one processor is configured to cause the MN to: generate a first set of trigger conditions related to a successful report, wherein the first set of trigger conditions is for at least one of the initial CPA or one or more subsequent CPCs of the subsequent CPAC procedure, or for at least one of the initial CPC or the one or more subsequent CPCs; and transmit the first set of trigger conditions to the UE.

In some implementations of the first network node described herein, the first network node is a master node (MN) , and the at least one processor is configured to cause the MN to: receive, from a secondary node (SN) managing a source PSCell in the initial CPA or the initial CPC, a second set of trigger conditions related to a successful report for the initial CPC; and transmit the second set of trigger conditions to the UE.

In some implementations of the first network node described herein, the first network node is a master node (MN) , and the at least one processor is configured to cause the MN to: receive at least one of the following from a candidate target secondary node (SN) : a third set of trigger conditions related to a successful report, wherein the third set of trigger conditions is for at least one of the initial CPA or one or more subsequent CPCs of the subsequent CPAC procedure, or for at least one of the initial CPC or the one or more subsequent CPCs; or a fourth set of trigger conditions related to the successful report for the one or more subsequent CPCs; and transmit at least one of the third set of trigger conditions and the fourth set of trigger conditions to the UE.

In some implementations of the first network node described herein, the first network node is a secondary node (SN) managing a source PSCell in the initial CPA or the initial CPC, and the at least one processor is configured to cause the SN to: generate a fifth set of trigger conditions related to a successful report for the initial CPC; and transmit the fifth set of trigger conditions to a master node (MN) or the UE.

In some implementations of the first network node described herein, the first set of trigger conditions, the second set of trigger conditions, the fourth set of trigger conditions, or the fifth set of trigger conditions is associated with timer T310 or timer T312, and the third set of trigger conditions is associated with timer T304.

In some implementations of the first network node described herein, the first set of trigger conditions for the one or more subsequent CPCs, the third set of trigger conditions for the one or more subsequent CPCs, or the fourth set of trigger conditions for the one or more subsequent CPCs include different or common trigger conditions for each of the one or more subsequent CPCs.

In some implementations of the first network node described herein, if common trigger conditions related to the successful report are generated for each of the one or more subsequent CPCs, the at least one processor is configured to cause the first network node to transmit, to the UE, information indicating that trigger conditions related to the successful report for each of the one or more subsequent CPCs are common.

In some implementations of the first network node described herein, the first network node is the MN, and the at least one processor is configured to cause the MN to: receive a successful report from the UE; and determine the successful report is for which one of the initial CPA, the initial CPC, and the subsequent CPC.

In some implementations of the first network node described herein, the first network node is the MN, and the at least one processor is configured to cause the MN to receive, from the UE, information indicating that the successful report is for the initial CPA, information indicating that the successful report is for the initial CPC, or information indicating that the successful report is for the subsequent CPC.

In some implementations of the first network node described herein, the first network node is the MN, and to determine the successful report is for which one of the initial CPA, the initial CPC, and the subsequent CPC, the at least one processor is configured to cause the MN to: if only one radio resource control (RRC) reconfiguration complete message is received before receiving the successful report, determine that the successful report is for the initial CPA or the initial CPC; if two RRC reconfiguration complete messages are received before receiving the successful report, determine whether a SCG failure information message is received; and if more than two RRC reconfiguration complete messages are received before receiving the successful report, determine that the successful report is for the subsequent CPC.

In some implementations of the first network node described herein, the first network node is the MN and during determining whether the SCG failure information message is received, the at least one processor is further configured to cause the MN to: if the SCG failure information message is received, determine that the successful report is for the initial CPA or the initial CPC; and if the SCG failure information message is not received, determine that the successful report is for the subsequent CPC.

In some implementations of the first network node described herein, the first network node is the MN, and the at least one processor is further configured to cause the MN to: if the successful report is for the initial CPA or the initial CPC: if the subsequent CPAC procedure is initiated by the MN, transmit the successful report to a SN managing a source PSCell in the initial CPA or the initial CPC; and if the subsequent CPAC procedure is initiated by the SN, transmit the successful report to the SN; and if the successful report is for the subsequent CPC, transmit the successful report to a target SN managing a target PSCell included in the successful report.

Some implementations of the present disclosure provide a processor for wireless communication, comprising at least one controller coupled with at least one memory and configured to cause the processor to: in case that a secondary cell group (SCG) failure occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure, determine the SCG failure occurs in which one of the following: an initial conditional PSCell addition (CPA) of the subsequent CPAC procedure; an initial conditional PSCell change (CPC) of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure, wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.

Some implementations of the present disclosure provide a method performed by a network node. The method includes: in case that a secondary cell group (SCG) failure occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure, determining whether the SCG failure occurs in which one of the following: an initial conditional PSCell addition (CPA) of the subsequent CPAC procedure; an initial conditional PSCell change (CPC) of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure, wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.

Some implementations of the present disclosure provide a candidate target secondary node (SN) . The candidate target SN includes at least one memory; and at least one processor coupled to the at least one memory and configured to cause the candidate target SN to: determine which one of the following occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure: wrong candidate target PSCell selection at the candidate target SN; and one or more wrong CPC execution conditions set at the candidate target SN, wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.

In some implementations of the candidate target SN described herein, the one or more wrong CPC execution conditions include one or more wrong CPC execution conditions for at least one subsequent CPC of the subsequent CPAC procedure.

In some implementations of the candidate target SN described herein, the at least one processor is configured to cause the candidate target SN to receive an indication from a network node, and wherein the indication indicates one of the following: at least one wrong candidate target PSCell is selected at the candidate target SN; at least one wrong CPC execution condition is set at the candidate target SN; secondary cell group (SCG) failure related information; and cell information of a PSCell selected during the subsequent CPAC procedure.

In some implementations of the candidate target SN described herein, the indication is received in case that: the selected PSCell is included in a first set of candidate target PSCells provided by a first network node, but not included in a second set of candidate target PSCells selected by the candidate target SN; or the selected PSCell is included in the second set of candidate target PSCells.

In some implementations of the candidate target SN described herein, the first network node is one of the following: a master node (MN) ; and a secondary node (SN) managing a source PSCell in the initial CPA or the initial CPC.

In some implementations of the candidate target SN described herein, the subsequent CPAC procedure includes: an initial conditional PSCell addition (CPA) ; an initial conditional PSCell change (CPC) ; and one or more subsequent CPCs.

In some implementations of the candidate target SN described herein, the at least one processor is configured to cause the candidate target SN to: generate a fourth set of trigger conditions related to a successful report for the one or more subsequent CPCs, wherein the fourth set of trigger conditions is associated with timer T310 or timer T312; and transmit the fourth set of trigger conditions to a master node (MN) .

In some implementations of the candidate target SN described herein, the at least one processor is configured to cause the candidate target SN to: generate a third set of trigger conditions related to a successful report, wherein the third set of trigger conditions is for at least one of the initial CPA or one or more subsequent CPCs of the subsequent CPAC procedure, or for at least one of the initial CPC or the one or more subsequent CPCs; and transmit the third set of trigger conditions to a master node (MN) , wherein the third set of trigger conditions is associated with timer T304.

In some implementations of the candidate target SN described herein, the third set of trigger conditions or the fourth set of trigger conditions for the one or more subsequent CPCs include different or common trigger conditions for each of the one or more subsequent CPCs.

In some implementations of the candidate target SN described herein, if common trigger conditions related to the successful report are generated for each of the one or more subsequent CPCs, the at least one processor is configured to cause the candidate target SN to transmit, to the UE, information indicating that trigger conditions related to the successful report for each of the one or more subsequent CPCs are common.

Some implementations of the present disclosure provide a processor for wireless communication, comprising at least one controller coupled with at least one memory and configured to cause the processor to: determine which one of the following occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure: wrong candidate target PSCell selection at the candidate target SN; and one or more wrong CPC execution conditions set at the candidate target SN, wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.

Some implementations of the present disclosure provide a method performed by a candidate target secondary node (SN) . The method includes: determining which one of the following occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure: wrong candidate target PSCell selection at the candidate target SN; and one or more wrong CPC execution conditions set at the candidate target SN, wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.

Some implementations of the present disclosure provide a user equipment (UE) . The UE includes at least one memory; and at least one processor coupled to the at least one memory and configured to cause the UE to: in case that a secondary cell group (SCG) failure occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure, transmit information indicating the SCG failure occurs in which one of: an initial conditional PSCell addition (CPA) of the subsequent CPAC procedure; an initial conditional PSCell change (CPC) of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure, wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.

In some implementations of the UE described herein, the at least one processor is configured to cause the UE to determine that the SCG failure occurs during the subsequent CPAC procedure in response to detecting an event, wherein the event is one of the following: the UE performs a CPC execution from a first PSCell to a second PSCell successfully, but within a predefined limited time the UE performs a CPC execution from the second PSCell to a third PSCell successfully; the UE performs the CPC execution from the first PSCell to the second PSCell, but the CPC execution is not successful or the SCG failure occurs shortly after the CPC execution is successful, wherein the first PSCell is a suitable PSCell based on measurements reported from the UE; and the UE receives configuration information for the subsequent CPAC procedure, while the SCG failure occurs before one or more executions condition of the initial CPC or the subsequent CPC are fulfilled.

In some implementations of the UE described herein, the event occurs at least once in the subsequent CPAC procedure.

In some implementations of the UE described herein, the at least one processor is configured to cause the UE to perform one of: receiving a set of trigger conditions related to a successful report, wherein the set of trigger conditions includes at least one of the following: a first set of trigger conditions, wherein the first set of trigger conditions is for at least one of the initial CPA or one or more subsequent CPCs of the subsequent CPAC procedure, or for at least one of the initial CPC or the one or more subsequent CPCs; a second set of trigger conditions for the initial CPC; or a fourth set of trigger conditions for the one or more subsequent CPCs; and generating a successful report.

In some implementations of the UE described herein, the set of trigger conditions is associated with at least one of timer T310, timer T312, or timer T304.

In some implementations of the UE described herein, the at least one processor is configured to cause the UE to transmit, to the MN, information indicating that the successful report is for the initial CPA, information indicating that the successful report is for the initial CPC, or information indicating that the successful report is for the subsequent CPC.

Some implementations of the present disclosure provide a processor for wireless communication, comprising at least one controller coupled with at least one memory and configured to cause the processor to: in case that a secondary cell group (SCG) failure occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure, transmit information indicating the SCG failure occurs in which one of the following: an initial conditional PSCell addition (CPA) of the subsequent CPAC procedure; an initial conditional PSCell change (CPC) of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure, wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.

Some implementations of the present disclosure provide a method performed by a user equipment (UE) . The method includes: in case that a secondary cell group (SCG) failure occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure, transmitting information indicating whether the SCG failure occurs in one of the following: an initial conditional PSCell addition (CPA) of the subsequent CPAC procedure; an initial conditional PSCell change (CPC) of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure, wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates an example of a wireless communications system in accordance with aspects of the present disclosure.

Figure 2 illustrates an example of a user equipment (UE) 200 in accordance with aspects of the present disclosure.

Figure 3 illustrates an example of a processor 300 in accordance with aspects of the present disclosure.

Figure 4 illustrates an example of a network equipment (NE) 400 in accordance with aspects of the present disclosure.

Figure 5 illustrates a schematic diagram of a wireless communication system in accordance with aspects of the present disclosure.

Figures 6 and 7 illustrate flowcharts of a method related to a subsequent CPAC procedure in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

Next generation radio access network (NG-RAN) supports a multi-radio dual connectivity (MR-DC) operation. In a MR-DC scenario, a user equipment (UE) with multiple transceivers may be configured to utilize resources provided by two different nodes connected via non-ideal backhauls. One node may provide new radio (NR) access and the other one node may provide either evolved-universal terrestrial radio access (UTRA) (E-UTRA) or NR access. One node may act as a master node (MN) and the other node may act as a secondary node (SN) . The MN and SN are connected via a network interface (for example, X2 or Xn interface as specified in 3rd Generation Partnership Project (3GPP) standard documents) , and at least the MN is connected to the core network. MR-DC includes NR-NR DC, EN-DC, NGEN-DC, and/or NE-DC. A MN can be an eNB, a ng-eNB, or a gNB. A SN can be a ng-eNB, an en-gNB, or a gNB.

In 3GPP Rel-18, subsequent CPAC would be introduced, to enhance PSCell mobility in case of NR-DC. In the present disclosure, subsequent CPAC may also be called as selective SCG activation, selective activation cell of groups, selective activation of PSCell, selective activation of SCG, conditional selective cell group or subsequent CPA or CPC, selective activation of PSCell change (SAPC) , or conditional selective cell group, or the like. Selective SCG activation may be performed in any MR-DC cases, which includes NR-NR DC, EN-DC, NGEN-DC, and/or NE-DC. In general, during a subsequent CPAC or a selective SCG activation procedure, after receiving configuration for the subsequent CPAC or SCG selective activation procedure, a UE may perform several CPAC executions (including initial CPAC execution (e.g. initial CPA execution or initial CPC execution) and one or more subsequent CPC executions) . For example, in an initial CPA of the subsequent CPAC procedure, the UE may perform initial CPA execution; in an initial CPC of the subsequent CPAC procedure, the UE may perform initial CPC execution; and in a subsequent CPC of the subsequent CPAC procedure, the UE may perform subsequent CPC execution. After finishing initial CPAC execution or one subsequent CPC execution, the UE doesn’t release the received configuration for the subsequent CPAC or SCG selective activation procedure (e.g. conditional configuration of candidate target PSCells for the subsequent CPAC or SCG selective activation procedure, which may be sent to the UE via an RRC reconfiguration message) , the UE continues evaluating the execution condition (s) of one or more candidate target PSCells configured for the subsequent CPAC procedure. It should be possible to release one or more candidate target PSCells explicitly by an RRC reconfiguration procedure.

Baseline procedure to support a subsequent CPAC or SCG selective activation procedure may be executed as below:

(1) Step 1: when the execution condition of a candidate target PSCell is met, a UE performs the execution of CPA or CPC towards this candidate target PSCell.

(2) Step 2: After finishing the PSCell addition or change, the UE doesn’t release conditional configuration of other candidate target PSCells for subsequent CPC, the UE continues evaluating the execution conditions of other candidate target PSCells.

(3) Step 3: When the execution condition of a candidate target PSCell is met, the UE performs the execution of CPC towards this candidate target PSCell.

For example, there may be the following scenarios of subsequent CPAC or SCG selective activation:

(1) SN initiated intra-SN subsequent CPAC or SCG selective activation

(2) MN initiated intra-SN subsequent CPAC or SCG selective activation

(3) MN initiated inter-SN subsequent CPAC or SCG selective activation

(4) SN initiated inter-SN subsequent CPAC or SCG selective activation

In a subsequent CPAC or SCG selective activation procedure, the received configuration for the subsequent CPAC or SCG selective activation procedure (e.g. the CPC or CPA configurations of the UE) should be released after PCell change, at least for inter-MN HO (e.g. by an explicit indication from network) .

A CPA conditional configuration can be used for subsequent CPC (but with different execution conditions) . For inter-SN subsequent CPAC or SCG selective activation, MN should provide the reference configuration to all candidate target SNs (T-SNs) (in order to generate the T-SN candidate configuration) . For MN initiated inter-SN subsequent CPAC or SCG selective activation, source MN may generate the CPAC (e.g. CPA or CPC) execution conditions for the initial CPAC (e.g. initial CPA or initial CPC) . There may be the following options for subsequent CPC:

Option#1: Source MN generates the CPC execution conditions for all subsequent CPC (s) .

Option#2: Candidate target SN may generate CPC execution conditions for subsequent CPC (s) .

For SN initiated inter-SN subsequent CPAC or SCG selective activation, source SN may generate the CPC execution conditions for the initial CPC. Candidate T-SN may generate CPC execution conditions for subsequent CPC (s) .

In 3GPP Rel-18, Successful PSCell change or addition Report (e.g. SPR) would be introduced, to optimize PSCell change or PSCell addition or CPC or CPA related parameters, e.g. if a physical layer issue is detected by a UE during an ongoing PSCell change or PSCell addition or CPC or CPA procedure. For the SPR, configurations for the UE to log or store or generate SPR is configured by the network, e.g. SPR-Config information element (IE) is configured via the RRC reconfiguration message to the UE, including at least one trigger condition, e.g. T304 related threshold (a threshold e.g. thresholdPercentageT304 generated by target PSCell or target SN, and the threshold may be a percentage value or an absolute value) , T310 related threshold (a threshold e.g. thresholdPercentageT310 generated by MN or source PSCell or source SN, and the threshold may be a percentage value or an absolute value) , or T312 related threshold (a threshold e.g. thresholdPercentageT312 generated by MN or source PSCell or source SN, and the threshold may be a percentage value or an absolute value) . Based on the network configuration, the UE stores successful PSCell change or addition or CPC or CPA related information or generates the VarSuccessPSCellChangeorAddition-Report or SPR when at least one trigger condition is satisfied and/or random access (RA) to a target PSCell is successful. SPR can be generated and reported to the network (e.g. source MN, source SN or target SN or other network node) , including successful PSCell change or PSCell addition or CPC or CPA related information, for example, at least one of: cell information of the source PSCell, cell information of the target PSCell, success PSCell change or addition cause value (e.g. t304, t310, t312 cause, etc. ) , measurement results of source PSCell and/or target PSCell and/or neighbour cell (s) , and RA information (e.g. RACH configurations for target PSCell) . The cell information may include global cell identity, tracking area code of the cell, and/or, PCI and carrier frequency information.

In general, a purpose of a SCG failure information procedure is to inform E-UTRAN or NR MN about a SCG failure the UE has experienced, i.e., a SCG radio link failure, a failure of SCG reconfiguration with sync, a SCG configuration failure for an RRC message on signalling radio bearer (SRB) 3, a SCG integrity check failure, and a consistent uplink listen-before-talk (LBT) failures on PSCell for operation with shared spectrum channel access. After the network receives the SCG failure information message, it can trigger the UE to perform a SN release or modification or change procedure. The following information (e.g. SCG failure related information) can be included in the SCG failure information message in case of a SCG failure: cell information of previous PSCell; cell information of failed PSCell; time SCG failure which indicates the time elapsed since the last execution of an RRC reconfiguration message with reconfigurationWithSync for the SCG until the SCG failure; RA-Information; measurement result (s) in MCG and/or measurement result (s) in SCG; and/or failure type. The cell information may include global cell identity, tracking area code of the cell, and/or, physical cell identifier (PCI) and carrier frequency information (e.g. an absolute radio frequency channel number (ARFCN) ) .

For analysis of PSCell change failure, the UE makes the SCG Failure Information available to the MN. The MN performs initial analysis to identify the node that caused the failure. The MN may use the SCG Failure Information Report procedure to verify whether intra-SN PSCell change has been triggered in the last serving SN and stores the SCG Failure Information for the time needed to receive possible response from the last serving SN. If the failure is caused by a source SN, the MN forwards then the SCG Failure Information to the source SN. The node responsible for the last PSCell change (the source SN, the last serving SN or the MN) performs the final root cause analysis.

One of the functions of self-optimization for PSCell change is to detect PSCell change failures that occur due to Too late PSCell change or Too early PSCell change, or Triggering PSCell change to wrong PSCell. These problems are defined as follows:

- Too late PSCell change: an SCG failure occurs after the UE has stayed for a long period of time in the PSCell; a suitable different PSCell is found based on the measurements reported from the UE.

- Too early PSCell change: an SCG failure occurs shortly after a successful PSCell change from a source PSCell to a target PSCell or a PSCell change failure occurs during the PSCell change procedure; source PSCell is still the suitable PSCell based on the measurements reported from the UE.

- Triggering PSCell change to wrong PSCell: an SCG failure occurs shortly after a successful PSCell change from a source PSCell to a target PSCell or a PSCell change failure occurs during the PSCell change procedure; a suitable PSCell different with source PSCell or target PSCell is found based on the measurements reported from the UE.

In the definition above, the "successful PSCell change" refers to the UE state, namely the successful completion of the RA procedure.

One of the functions of self-optimization for CPAC is to detect CPAC failures that occur due to Too late CPC execution or Too early CPC/CPA execution, or CPC/CPA execution to wrong PSCell. These problems are defined as follows:

- Too Late CPC Execution: UE receives CPC configuration, while a SCG failure occurs before CPC execution condition is satisfied; a suitable PSCell different from source PSCell is found based on the measurements reported from the UE.

- Too Early CPC/CPA Execution: CPC/CPA execution is not successful or an SCG failure occurs shortly after a successful CPC/CPA execution; in case of CPC, the source PSCell is still the suitable PSCell based on the measurements reported from the UE; in case of CPA, no suitable PSCell is found based on the measurements reported from the UE.

- CPC/CPA Execution to wrong PSCell: CPC/CPA execution is not successful or an SCG failure occurs shortly after a successful CPC/CPA execution; a suitable PSCell different from the source PSCell or the target PSCell is found based on the measurements reported from the UE. There are two sub-cases:

- if the suitable PSCell is one of the candidate target PSCells provided by the node initiating the CPC or by the MN initiating the CPA to a (candidate) target SN, but not one of the candidate PSCells selected by the (candidate) target SN, it is wrong target PSCell selection at the (candidate) target SN;

- else, it is wrong candidate PSCell list selection at the node initiating the CPC or at the MN initiating the CPA.

In the definition above, the "successful CPC/CPA execution" refers to the UE state, namely the successful completion of the RA procedure.

Currently, details regarding a MRO mechanism for a subsequent CPAC procedure, e.g. in a MR-DC scenario, have not been discussed yet. Embodiments of the present disclosure aim to resolve the abovementioned problem. Some embodiments of the present application define failure type definition for ping-pong in subsequent CPAC, wrong subsequent CPAC, too early subsequent CPAC and too late subsequent CPAC. Some embodiments of the present disclosure study a MRO mechanism for a SCG failure in a MN or SN initiated subsequent CPAC procedure. Some embodiments of the present disclosure study a MRO mechanism for a near-failure successful case in a MN or SN initiated subsequent CPAC procedure.

More specifically, in some embodiments of the present disclosure, regarding a MRO mechanism handling at the network side is a SCG failure occurs in initial CPAC (e.g. initial CPA or initial CPC) : if the selected PSCell (e.g. which is a suitable PSCell selected after the SCG failure) is not included in the candidate target PSCells provided by a network node (e.g. MN or initial source SN which initiates the subsequent CPAC procedure) , the network node detects that it is wrong candidate target PSCell selection; if the selected PSCell (e.g. which is a suitable PSCell selected after the SCG failure) is included in the candidate target PSCells provided by the network node, but not included in the candidate target PSCells selected or prepared by at least one of a (candidate) target SN (T-SN) , the network node may inform the at least one of a (candidate) T-SN that wrong candidate target PSCell (s) are selected or prepared directly or indirectly via a forwarding network node (e.g. MN) , or, the network node may forward SCG failure related information and cell information of the selected PSCell to the (candidate) T-SN, the (candidate) T-SN detects that it is wrong candidate target PSCell selection; if the selected PSCell (e.g. which is a suitable PSCell selected after the SCG failure) is included in the candidate target PSCells selected or prepared by the at least one of a (candidate) T-SN, the network node detects that it is wrong CPAC execution condition (s) setting or decision for initial CPAC.

In some embodiments of the present disclosure, regarding a MRO mechanism handling at the network side if a SCG failure occurs in subsequent CPC: if the selected PSCell (e.g. which is a suitable PSCell selected after the SCG failure) is not included in the candidate target PSCells provided by a network node (e.g. MN or initial source SN which initiates the subsequent CPAC procedure) , the network node detects that it is wrong candidate target PSCell selection; if the selected PSCell (e.g. which is a suitable PSCell selected after the SCG failure) is included in the candidate target PSCells provided by the network node, but not included in the candidate target PSCells selected or prepared by at least one of a (candidate) T-SN, the network node may inform the at least one of a (candidate) T-SN that wrong candidate target PSCell (s) are selected or prepared directly or indirectly via a forwarding network node (e.g. MN) , or, the network node may forward SCG failure related information and cell information of the selected PSCell to the (candidate) T-SN, the (candidate) T-SN detects that it is wrong candidate target PSCell selection; if the selected PSCell (e.g. which is a suitable PSCell selected after the SCG failure) is included in the candidate target PSCells selected or prepared by the at least one of a (candidate) T-SN, the network node may inform the at least one of a (candidate) T-SN that wrong CPAC execution condition (s) for subsequent CPC are set or decided directly or indirectly via a forwarding network node (e.g. MN) , or, the network node may forward SCG failure related information and cell information of the selected PSCell to the (candidate) T-SN, the (candidate) T-SN detects that it is wrong CPAC execution condition (s) for subsequent CPC setting or decision at the (candidate) T-SN.

In the embodiments of the present disclosure, in a SN initiated Subsequent CPAC or SCG selective activation procedure, a SN which initiates the Subsequent CPAC or SCG selective activation procedure is "an initial source SN (i.e. a node that manages a source PSCell in initial CPAC " or "a source SN during the initial CPA or the initial CPC or “a SN managing a source PSCell in the initial CPA or the initial CPC” ) . In a MN initiated Subsequent CPAC or SCG selective activation procedure, it is a MN to initiate the Subsequent CPAC or SCG selective activation procedure, and a SN may act as an initial source SN (i.e. a node that manages a source PSCell in initial CPAC procedure or a source SN during the initial CPA or the initial CPC or a SN managing a source PSCell in the initial CPA or initial CPC) or may act as a candidate target SN (i.e. a node that manages a target PSCell in initial CPA or in initial CPC or in subsequent CPC) .

In some embodiments of the present disclosure, to enable the network to know whether a SCG failure occurs in initial CPAC or subsequent CPC, UE-based (e.g. a UE indicates whether a SCG failure occurs in initial CPAC or subsequent CPC) , or network-based solution can be considered (e.g. based on a total number of RRC (connection) reconfiguration complete message (s) received before the SCG failure information message, and/or, time duration between the RRC (connection) reconfiguration complete message and the SCG failure information message) . For instance, in some embodiments for a Subsequent CPAC procedure in EN-DC or NGEN-DC scenario, the RRC (connection) reconfiguration complete message is an RRC connection reconfiguration complete message. In some embodiments for the Subsequent CPAC procedure in NE-DC or NR-DC scenario, the RRC (connection) reconfiguration complete message is an RRC reconfiguration complete message.

In some embodiments of the present disclosure, the initiating node (e.g. MN or initial source SN) decides or generates T310 or T312 related trigger condition (s) of a SPR or a new report for initial CPC, each (candidate) T-SN decides or generates T310 or T312 related trigger condition (s) of the SPR or the new report for subsequent CPC (e.g. T310 related trigger condition (s) of the SPR or the new report for each one of subsequent CPC procedures may be common or different, or T312 related trigger condition (s) of the SPR or the new report for each one of subsequent CPC procedures may be common or different) ; (candidate) T-SN decides or generates T304 related trigger condition (s) of the SPR or the new report for both initial CPC and subsequent CPC, T304 related trigger condition (s) of the SPR or the new report for initial CPC and subsequent CPC may be the same or different. The new report may be a report introduced for a PCell change with PSCell change procedure, or may be a report introduced for a subsequent CPAC procedure. To enable correct SPR forwarding at the network side, UE-based (e.g. a UE indicates whether SPR or the new report is generated for initial CPC or subsequent CPC) or network-based solution can be considered (e.g. based on a total number of RRC (connection) reconfiguration complete message (s) received before SPR, and/or, whether SCG failure information message is received) .

In the embodiments of the present disclosure, a T304 related trigger condition may be T304 related threshold, e.g. a percentage value. Similarly, a T310 related trigger condition may be T310 related threshold, e.g. a percentage value. A T312 related trigger condition may be T312 related threshold, e.g. a percentage value.

More details of the embodiments of the present disclosure will be illustrated in the following text in combination with the appended drawings.

Figure 1 illustrates an example of a wireless communications system 100 in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more NE 102, one or more UE 104, and a core network (CN) 106. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as an LTE network or an LTE-Advanced (LTE-A) network. In some other implementations, the wireless communications system 100 may be a NR network, such as a 5G network, a 5G-Advanced (5G-A) network, or a 5G ultrawideband (5G-UWB) network. In other implementations, the wireless communications system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20. The wireless communications system 100 may support radio access technologies beyond 5G, for example, 6G. Additionally, the wireless communications system 100 may support technologies, such as time division multiple access (TDMA) , frequency division multiple access (FDMA) , or code division multiple access (CDMA) , etc.

The one or more NE 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the NE 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a network function, a network entity, a radio access network (RAN) , a NodeB, an eNodeB (eNB) , a next-generation NodeB (gNB) , or other suitable terminology. An NE 102 and a UE 104 may communicate via a communication link, which may be a wireless or wired connection. For example, an NE 102 and a UE 104 may perform wireless communication (e.g. receive signaling, transmit signaling) over a Uu interface.

An NE 102 may provide a geographic coverage area for which the NE 102 may support services for one or more UEs 104 within the geographic coverage area. For example, an NE 102 and a UE 104 may support wireless communication of signals related to services (e.g. voice, video, packet data, messaging, broadcast, etc. ) according to one or multiple radio access technologies. In some implementations, an NE 102 may be moveable, for example, a satellite associated with a non-terrestrial network (NTN) . In some implementations, different geographic coverage areas 112 associated with the same or different radio access technologies may overlap, but the different geographic coverage areas may be associated with different NE 102.

The one or more UE 104 may be dispersed throughout a geographic region of the wireless communications system 100. A UE 104 may include or may be referred to as a remote unit, a mobile device, a wireless device, a remote device, a subscriber device, a transmitter device, a receiver device, or some other suitable terminology. In some implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an Internet-of-Things (IoT) device, an Internet-of-Everything (IoE) device, or machine-type communication (MTC) device, among other examples.

AUE 104 may be able to support wireless communication directly with other UEs 104 over a communication link. For example, a UE 104 may support wireless communication directly with another UE 104 over a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link 114 may be referred to as a sidelink. For example, a UE 104 may support wireless communication directly with another UE 104 over a PC5 interface.

An NE 102 may support communications with the CN 106, or with another NE 102, or both. For example, an NE 102 may interface with other NE 102 or the CN 106 through one or more backhaul links (e.g. S1, N2, N2, or network interface) . In some implementations, the NE 102 may communicate with each other directly. In some other implementations, the NE 102 may communicate with each other or indirectly (e.g. via the CN 106. In some implementations, one or more NE 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC) . An ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as a radio heads, smart radio heads, or transmission-reception points (TRPs) .

The CN 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The CN 106 may be an evolved packet core (EPC) , or a 5G core (5GC) , which may include a control plane entity that manages access and mobility (e.g. a mobility management entity (MME) , an access and mobility management functions (AMF) ) and a user plane entity that routes packets or interconnects to external networks (e.g. a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g. data bearers, signal bearers, etc. ) for the one or more UEs 104 served by the one or more NE 102 associated with the CN 106.

The CN 106 may communicate with a packet data network over one or more backhaul links (e.g. via an S1, N2, N2, or another network interface) . The packet data network may include an application server. In some implementations, one or more UEs 104 may communicate with the application server. A UE 104 may establish a session (e.g. a protocol data unit (PDU) session, or the like) with the CN 106 via an NE 102. The CN 106 may route traffic (e.g. control information, data, and the like) between the UE 104 and the application server using the established session (e.g. the established PDU session) . The PDU session may be an example of a logical connection between the UE 104 and the CN 106 (e.g. one or more network functions of the CN 106) .

In the wireless communications system 100, the NEs 102 and the UEs 104 may use resources of the wireless communications system 100 (e.g. time resources (e.g. symbols, slots, subframes, frames, or the like) or frequency resources (e.g. subcarriers, carriers) ) to perform various operations (e.g. wireless communications) . In some implementations, the NEs 102 and the UEs 104 may support different resource structures. For example, the NEs 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the NEs 102 and the UEs 104 may support a single frame structure. In some other implementations, such as in 5G and among other suitable radio access technologies, the NEs 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures) . The NEs 102 and the UEs 104 may support various frame structures based on one or more numerologies.

One or more numerologies may be supported in the wireless communications system 100, and a numerology may include a subcarrier spacing and a cyclic prefix. A first numerology (e.g. μ=0) may be associated with a first subcarrier spacing (e.g. 15 kHz) and a normal cyclic prefix. In some implementations, the first numerology (e.g. μ=0) associated with the first subcarrier spacing (e.g. 15 kHz) may utilize one slot per subframe. A second numerology (e.g. μ=1) may be associated with a second subcarrier spacing (e.g. 30 kHz) and a normal cyclic prefix. A third numerology (e.g. μ=2) may be associated with a third subcarrier spacing (e.g. 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g. μ=3) may be associated with a fourth subcarrier spacing (e.g. 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g. μ=4) may be associated with a fifth subcarrier spacing (e.g. 240 kHz) and a normal cyclic prefix.

A time interval of a resource (e.g. a communication resource) may be organized according to frames (also referred to as radio frames) . Each frame may have a duration, for example, a 10 millisecond (ms) duration. In some implementations, each frame may include multiple subframes. For example, each frame may include 10 subframes, and each subframe may have a duration, for example, a 1 ms duration. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

Additionally or alternatively, a time interval of a resource (e.g. a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g. quantity) of slots. The number of slots in each subframe may also depend on the one or more numerologies supported in the wireless communications system 100. For instance, the first, second, third, fourth, and fifth numerologies (i.e., μ=0, μ=1, μ=2, μ=3, μ=4) associated with respective subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and 16 slots per subframe, respectively. Each slot may include a number (e.g. quantity) of symbols (e.g. OFDM symbols) . In some implementations, the number (e.g. quantity) of slots for a subframe may depend on a numerology. For a normal cyclic prefix, a slot may include 14 symbols. For an extended cyclic prefix (e.g. applicable for 60 kHz subcarrier spacing) , a slot may include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that reference to a first numerology (e.g. μ=0) associated with a first subcarrier spacing (e.g. 15 kHz) may be used interchangeably between subframes and slots.

In the wireless communications system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, the wireless communications system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz –7.125 GHz) , FR2 (24.25 GHz –52.6 GHz) , FR3 (7.125 GHz –24.25 GHz) , FR4 (52.6 GHz –114.25 GHz) , FR4a or FR4-1 (52.6 GHz –71 GHz) , and FR5 (114.25 GHz –300 GHz) . In some implementations, the NEs 102 and the UEs 104 may perform wireless communications over one or more of the operating frequency bands. In some implementations, FR1 may be used by the NEs 102 and the UEs 104, among other equipment or devices for cellular communications traffic (e.g. control information, data) . In some implementations, FR2 may be used by the NEs 102 and the UEs 104, among other equipment or devices for short-range, high data rate capabilities.

FR1 may be associated with one or multiple numerologies (e.g. at least three numerologies) . For example, FR1 may be associated with a first numerology (e.g. μ=0) , which includes 15 kHz subcarrier spacing; a second numerology (e.g. μ=1) , which includes 30 kHz subcarrier spacing; and a third numerology (e.g. μ=2) , which includes 60 kHz subcarrier spacing. FR2 may be associated with one or multiple numerologies (e.g. at least 2 numerologies) . For example, FR2 may be associated with a third numerology (e.g. μ=2) , which includes 60 kHz subcarrier spacing; and a fourth numerology (e.g. μ=3) , which includes 120 kHz subcarrier spacing.

Figure 2 illustrates an example of a UE 200 in accordance with aspects of the present disclosure. The UE 200 may include a processor 202, a memory 204, a controller 206, and a transceiver 208. The processor 202, the memory 204, the controller 206, or the transceiver 208, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g. operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

The processor 202, the memory 204, the controller 206, or the transceiver 208, or various combinations or components thereof may be implemented in hardware (e.g. circuitry) . The hardware may include a processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

The processor 202 may include an intelligent hardware device (e.g. a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof) . In some implementations, the processor 202 may be configured to operate the memory 204. In some other implementations, the memory 204 may be integrated into the processor 202. The processor 202 may be configured to execute computer-readable instructions stored in the memory 204 to cause the UE 200 to perform various functions of the present disclosure.

The memory 204 may include volatile or non-volatile memory. The memory 204 may store computer-readable, computer-executable code including instructions when executed by the processor 202 cause the UE 200 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such the memory 204 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

In some implementations, the processor 202 and the memory 204 coupled with the processor 202 may be configured to cause the UE 200 to perform one or more of the functions described herein (e.g. executing, by the processor 202, instructions stored in the memory 204) . For example, the processor 202 may support wireless communication at the UE 200 in accordance with examples as disclosed herein. In case that a SCG failure occurs during a subsequent CPAC procedure, the UE 200 may be configured to support a means for transmitting information indicating whether the SCG failure occurs in one of the following: an initial CPA of the subsequent CPAC procedure; an initial CPC of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure.

The controller 206 may manage input and output signals for the UE 200. The controller 206 may also manage peripherals not integrated into the UE 200. In some implementations, the controller 206 may utilize an operating system such as or other operating systems. In some implementations, the controller 206 may be implemented as part of the processor 202.

In some implementations, the UE 200 may include at least one transceiver 208. In some other implementations, the UE 200 may have more than one transceiver 208. The transceiver 208 may represent a wireless transceiver. The transceiver 208 may include one or more receiver chains 210, one or more transmitter chains 212, or a combination thereof. The means for receiving abovementioned in the processor 202 or the means for transmitting in the processor 202 may be implemented via at least one transceiver 208.

A receiver chain 210 may be configured to receive signals (e.g. control information, data, packets) over a wireless medium. For example, the receiver chain 210 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 210 may include at least one amplifier (e.g. a low-noise amplifier (LNA) ) configured to amplify the received signal. The receiver chain 210 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 210 may include at least one decoder for decoding the processing the demodulated signal to receive the transmitted data.

A transmitter chain 212 may be configured to generate and transmit signals (e.g. control information, data, packets) . The transmitter chain 212 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM) , frequency modulation (FM) , or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM) . The transmitter chain 212 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 212 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

Figure 3 illustrates an example of a processor 300 in accordance with aspects of the present disclosure. The processor 300 may be an example of a processor configured to perform various operations in accordance with examples as described herein. The processor 300 may include a controller 302 configured to perform various operations in accordance with examples as described herein. The processor 300 may optionally include at least one memory 304, which may be, for example, an L1/L2/L3 cache. Additionally, or alternatively, the processor 300 may optionally include one or more arithmetic-logic units (ALUs) 306. One or more of these components may be in electronic communication or otherwise coupled (e.g. operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g. buses) .

The processor 300 may be a processor chipset and include a protocol stack (e.g. a software stack) executed by the processor chipset to perform various operations (e.g. receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) in accordance with examples as described herein. The processor chipset may include one or more cores, one or more caches (e.g. memory local to or included in the processor chipset (e.g. the processor 300) or other memory (e.g. random access memory (RAM) , read-only memory (ROM) , dynamic RAM (DRAM) , synchronous dynamic RAM (SDRAM) , static RAM (SRAM) , ferroelectric RAM (FeRAM) , magnetic RAM (MRAM) , resistive RAM (RRAM) , flash memory, phase change memory (PCM) , and others) .

The controller 302 may be configured to manage and coordinate various operations (e.g. signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of the processor 300 to cause the processor 300 to support various operations in accordance with examples as described herein. For example, the controller 302 may operate as a control unit of the processor 300, generating control signals that manage the operation of various components of the processor 300. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating timing of operations.

The controller 302 may be configured to fetch (e.g. obtain, retrieve, receive) instructions from the memory 304 and determine subsequent instruction (s) to be executed to cause the processor 300 to support various operations in accordance with examples as described herein. The controller 302 may be configured to track memory address of instructions associated with the memory 304. The controller 302 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 302 may be configured to interpret the instruction and determine control signals to be output to other components of the processor 300 to cause the processor 300 to support various operations in accordance with examples as described herein. Additionally, or alternatively, the controller 302 may be configured to manage flow of data within the processor 300. The controller 302 may be configured to control transfer of data between registers, arithmetic logic units (ALUs) , and other functional units of the processor 300.

The memory 304 may include one or more caches (e.g. memory local to or included in the processor 300 or other memory, such RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some implementations, the memory 304 may reside within or on a processor chipset (e.g. local to the processor 300) . In some other implementations, the memory 304 may reside external to the processor chipset (e.g. remote to the processor 300) .

The memory 304 may store computer-readable, computer-executable code including instructions that, when executed by the processor 300, cause the processor 300 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. The controller 302 and/or the processor 300 may be configured to execute computer-readable instructions stored in the memory 304 to cause the processor 300 to perform various functions. For example, the processor 300 and/or the controller 302 may be coupled with or to the memory 304, the processor 300, the controller 302, and the memory 304 may be configured to perform various functions described herein. In some examples, the processor 300 may include multiple processors and the memory 304 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may, individually or collectively, be configured to perform various functions herein.

The one or more ALUs 306 may be configured to support various operations in accordance with examples as described herein. In some implementations, the one or more ALUs 306 may reside within or on a processor chipset (e.g. the processor 300) . In some other implementations, the one or more ALUs 306 may reside external to the processor chipset (e.g. the processor 300) . One or more ALUs 306 may perform one or more computations such as addition, subtraction, multiplication, and division on data. For example, one or more ALUs 306 may receive input operands and an operation code, which determines an operation to be executed. One or more ALUs 306 be configured with a variety of logical and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation. Additionally, or alternatively, the one or more ALUs 306 may support logical operations such as AND, OR, exclusive-OR (XOR) , not-OR (NOR) , and not-AND (NAND) , enabling the one or more ALUs 306 to handle conditional operations, comparisons, and bitwise operations.

The processor 300 may support wireless communication in accordance with examples as disclosed herein.

In some further implementations, the processor 300 may be configured to support means for performing operations as described with respect to Figure 6. For example, in case that a SCG failure occurs during a subsequent CPAC procedure, the processor 300 may be configured to or operable to support a means for determining whether the SCG failure occurs in which one of the following: an initial CPA of the subsequent CPAC procedure; an initial CPC of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure.

In some implementations, the processor 300 may be configured to support means for performing operations as described with respect to Figure 7. For example, in case that a SCG failure occurs during a subsequent CPAC procedure, the processor 300 may be configured to or operable to support a means for transmitting information indicating whether the SCG failure occurs in one of the following: an initial CPA of the subsequent CPAC procedure; an initial CPC of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure.

In some additional implementations, the processor 300 may be configured to support means for performing operations of a candidate target SN. For example, the processor 300 may be configured to or operable to support a means for determining which one of the following occurs during a subsequent CPAC procedure: wrong candidate target PSCell selection at the candidate target SN; and one or more wrong CPC execution conditions set at the candidate target SN.

It should be appreciated by persons skilled in the art that the components in exemplary processor 300 may be changed, for example, some of the components in exemplary processor 300 may be omitted or modified or new component (s) may be added to exemplary processor 300, without departing from the spirit and scope of the disclosure. For example, in some embodiments, the processor 300 may not include the ALUs 306.

Figure 4 illustrates an example of a NE 400 in accordance with aspects of the present disclosure. The NE 400 may include a processor 402, a memory 404, a controller 406, and a transceiver 408. The processor 402, the memory 404, the controller 406, or the transceiver 408, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g. operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

The processor 402, the memory 404, the controller 406, or the transceiver 408, or various combinations or components thereof may be implemented in hardware (e.g. circuitry) . The hardware may include a processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

The processor 402 may include an intelligent hardware device (e.g. a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof) . In some implementations, the processor 402 may be configured to operate the memory 404. In some other implementations, the memory 404 may be integrated into the processor 402. The processor 402 may be configured to execute computer-readable instructions stored in the memory 404 to cause the NE 400 to perform various functions of the present disclosure.

The memory 404 may include volatile or non-volatile memory. The memory 404 may store computer-readable, computer-executable code including instructions when executed by the processor 402 cause the NE 400 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such the memory 404 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

In some implementations, the processor 402 and the memory 404 coupled with the processor 402 may be configured to cause the NE 400 to perform one or more of the functions described herein (e.g. executing, by the processor 402, instructions stored in the memory 404) . For example, the processor 402 may support wireless communication at the NE 400 in accordance with examples as disclosed herein. For example, the NE 400 may be configured to support means for performing the operations as described with respect to Figure 6 or operations of a candidate target SN as described below.

In some implementations, in case that a SCG failure occurs during a subsequent CPAC procedure, the NE 400 may be a MN (e.g. a MN initiating a subsequent CPAC procedure) or an initial source SN which initiates a subsequent CPAC procedure (e.g. a SN managing a source PSCell in an initial CPA or an initial CPC of the subsequent CPAC procedure) , and configured to support a means for determining whether the SCG failure occurs in which one of the following: an initial CPA of the subsequent CPAC procedure; an initial CPC of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure.

In some implementations, the NE 400 may be a candidate target SN and configured to support a means for determining which one of the following occurs during a subsequent CPAC procedure: wrong candidate target PSCell selection at the candidate target SN; and one or more wrong CPC execution conditions set at the candidate target SN.

The controller 406 may manage input and output signals for the NE 400. The controller 406 may also manage peripherals not integrated into the NE 400. In some implementations, the controller 406 may utilize an operating system such as or other operating systems. In some implementations, the controller 406 may be implemented as part of the processor 402.

In some implementations, the NE 400 may include at least one transceiver 408. In some other implementations, the NE 400 may have more than one transceiver 408. The transceiver 408 may represent a wireless transceiver. The transceiver 408 may include one or more receiver chains 410, one or more transmitter chains 412, or a combination thereof. The means for receiving or the means for transmitting abovementioned in the processor 402 may be implemented via at least one transceiver 408.

A receiver chain 410 may be configured to receive signals (e.g. control information, data, packets) over a wireless medium. For example, the receiver chain 410 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 410 may include at least one amplifier (e.g. a low-noise amplifier (LNA) ) configured to amplify the received signal. The receiver chain 410 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 410 may include at least one decoder for decoding the processing the demodulated signal to receive the transmitted data.

Atransmitter chain 412 may be configured to generate and transmit signals (e.g. control information, data, packets) . The transmitter chain 412 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM) , frequency modulation (FM) , or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM) . The transmitter chain 412 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 412 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

It should be appreciated by persons skilled in the art that the components in exemplary NE 400 may be changed, for example, some of the components in exemplary NE 400 may be omitted or modified or new component (s) may be added to exemplary NE 400, without departing from the spirit and scope of the disclosure. For example, in some embodiments, the NE 400 may not include the controller 406.

Figure 5 illustrates a schematic diagram of a wireless communication system in accordance with aspects of the present disclosure. As shown in FIG. 5, the wireless communication system 500 may be a dual connectivity system 500, including at least one UE 501, at least one MN 502, and at least one SN 503. In particular, the dual connectivity system 500 in FIG. 5 includes one shown UE 501, one shown MN 502, and one shown SN 503 for illustrative purpose. Although a specific number of UEs 501, MNs 502, and SNs 503 are depicted in FIG. 5, it is contemplated that any number of UEs 501, MNs 502, and SNs 503 may be included in the wireless communication system 500.

Referring to FIG. 5, UE 501 may be connected to MN 502 and SN 503 via a network interface, for example, the Uu interface as specified in 3GPP standard documents. MN 502 and SN 503 may be connected with each other via a network interface, for example, the Xn interface as specified in 3GPP standard documents for NR-NR DC or NGEN-DC or NE-DC, or X2 interface as specified in 3GPP standard documents for EN-DC. MN 502 may be connected to the core network via a network interface (not shown in FIG. 5) . UE 501 may be configured to utilize resources provided by MN 502 and SN 503 to perform data transmission.

MN 502 may refer to a radio access node that provides a control plane connection to the core network. In an embodiment of the present disclosure, in the E-UTRA-NR Dual Connectivity (EN-DC) scenario, MN 502 may be an eNB. In another embodiment of the present disclosure, in the next generation E-UTRA-NR Dual Connectivity (NGEN-DC) scenario, MN 502 may be an ng-eNB. In yet another embodiment of the present disclosure, in the NR-E-UTRA Dual Connectivity (NE-DC) scenario or the NR-NR Dual Connectivity (NR-DC) scenario, MN 502 may be a gNB.

MN 502 may be associated with a master cell group (MCG) . The MCG may refer to a group of serving cells associated with MN 502, and may include a primary cell (PCell) and optionally one or more secondary cells (SCells) of the MCG. The PCell may provide a control plane connection to UE 501.

SN 503 may refer to a radio access node without a control plane connection to the core network but providing additional resources to UE 501. In an embodiment of the present disclosure, in the EN-DC scenario, SN 503 may be an en-gNB. In another embodiment of the present disclosure, in the NE-DC scenario, SN 503 may be a ng-eNB. In yet another embodiment of the present disclosure, in the NR-DC scenario or the NGEN-DC scenario, SN 503 may be a gNB.

SN 503 may be associated with a secondary cell group (SCG) . The SCG may refer to a group of serving cells associated with SN 503, and may include a primary secondary cell group cell (PSCell) and optionally one or more secondary cells (SCells) . The PCell of the MCG and the PSCell of the SCG may also be referred to as a special cell (SpCell) .

In particular, some embodiments of the present disclosure define following event types in a Subsequent CPAC or SCG selective activation procedure, i.e., Embodiments 1-1, 1-2, 1-3, and 1-4 as below. One of the functions of MRO is to detect the event (s) that occur in a Subsequent CPAC or SCG selective activation procedure. The event types may also be named as "problem types" or "failure types" or "case types" or the like.

Embodiment 1-1 (ping-pong)

The event of "ping-pong (s) in a Subsequent CPAC or SCG selective activation procedure" may be defined as follows:

- A UE performs CPC execution/PSCell change from one PSCell (e.g. PSCell#1) to another PSCell (e.g. PSCell#2) successfully, but within a predefined limited time the UE performs CPC execution/PSCell change from the another PSCell (e.g. PSCell#2) back to the one PSCell (e.g. PSCell#1) successfully. The event may occur more than once in a Subsequent CPAC or SCG selective activation procedure.

Statistics regarding ping-pong occurrences in a Subsequent CPAC or SCG selective activation procedure may be collected by a MN. Ping-pong in a Subsequent CPAC or SCG selective activation procedure may be detected or analysed by the MN, in the following two options:

(1) Option#A: based on SCG UE History Information stored by a MN or based on SCG UE History Information received from a UE or source SN or any candidate target SN. For example, based on the time duration of the UE staying in PSCell#1, or PSCell#2, or when back to PSCell#1, if within a predefined limited time the UE leaves PSCell#2 and then back to PSCell#1, or if the UE stays in PSCell#2 for a short predefined time, a MN detects it as a ping-pong case.

(2) Option#B: based on RRC (connection) reconfiguration complete message received from a UE. For example, the received RRC (connection) reconfiguration complete message indicates the target PSCell selected by the UE for CPAC execution, based on the time duration between receiving the RRC (connection) reconfiguration complete message for PSCell#1 and receiving the RRC (connection) reconfiguration complete message for PSCell#2, and/or, based on the time duration between receiving the RRC (connection) reconfiguration complete message for PSCell#2 and receiving the RRC (connection) reconfiguration complete message for back to PSCell#1, if within a predefined limited time the UE leaves PSCell#2 and then back to PSCell#1, or if the UE stays in PSCell#2 for a short predefined time, a MN detects it as a ping-pong case.

AMN may indicate the occurrence of potential ping-pong case to the initial source SN (the node that manages the source PSCell in initial CPAC procedure) or the corresponding SN (e.g. the SN that manages the PSCell#1, or the SN that manages the PSCell#2) .

Embodiment 1-2 (wrong Subsequent CPAC or SCG selective activation)

The failure type of "wrong Subsequent CPAC or SCG selective activation" may be defined as follows:

- A UE performs CPC execution/PSCell change from one PSCell (e.g. PSCell#a) to another PSCell (e.g. PSCell#b) successfully, but within a predefined limited time the UE performs CPC execution/PSCell change from the another PSCell (e.g. PSCell#b) to an additional PSCell (e.g. PSCell#c) successfully. The event may occur more than once in a Subsequent CPAC or SCG selective activation procedure.

The above wrong Subsequent CPAC or SCG selective activation may be detected or analysed by a MN, in the following two options:

(1) Option#M: based on SCG UE History Information stored by A MN or based on SCG UE History Information received from a UE or source SN or any candidate target SN. For example, based on the time duration of UE staying in PSCell#a, PSCell#b or PSCell#c, if within a predefined limited time the UE leaves PSCell#b and enters PSCell#c, or if the UE stays in PSCell#b for a short predefined time, a MN detects it as a wrong Subsequent CPAC or SCG selective activation case.

(2) Option#N: based on RRC (connection) reconfiguration complete message received from a UE. For example, the received RRC (connection) reconfiguration complete message indicates the target PSCell selected by the UE for CPAC execution, based on the time duration between receiving the RRC (connection) reconfiguration complete message for PSCell#aand receiving the RRC (connection) reconfiguration complete message for PSCell#b, and/or, based on the time duration between receiving the RRC (connection) reconfiguration complete message for PSCell#b and receiving the RRC (connection) reconfiguration complete message for PSCell#c, if within a predefined limited time the UE leaves PSCell#b and then back to PSCell#a, or if the UE stays in PSCell#b for a short predefined time, a MN detects it as a wrong Subsequent CPAC or SCG selective activation case.

Also, as failure type definition of CPC/CPA Execution to wrong PSCell for legacy CPAC procedure in 3GPP Rel-18, the failure type of "wrong Subsequent CPAC or SCG selective activation" can be defined as below:

- initial CPAC execution or subsequent CPC execution is not successful or an SCG failure occurs shortly after a successfully initial CPAC execution or subsequent CPC execution; a suitable PSCell different from the PSCell which is treated as source PSCell when the initial CPAC execution or subsequent CPC execution is triggered or the target PSCell is found based on the measurements reported from a UE.

A MN may indicate the occurrence of wrong Subsequent CPAC or SCG selective activation to the initial source SN or the corresponding SN (e.g. the SN that manages PSCell#a, or the SN that manages PSCell#b, or the SN that manages PSCell#c, or the node manages the source PSCell when the subsequent CPC execution is triggered, or the node manages the target PSCell) .

Embodiment 1-3 (too early Subsequent CPAC or SCG selective activation)

The failure type of "too early Subsequent CPAC or SCG selective activation" may be defined as follows:

- A UE performs CPC execution/PSCell change from one PSCell (e.g. PSCell#x) to another PSCell (e.g. PSCell#y) , but CPC execution/PSCell change is not successful or an SCG failure occurs shortly after a successful CPC execution/PSCell change, PSCell#x is the suitable PSCell based on the measurements reported from the UE. For example, PSCell#x may be the source PSCell when initial CPAC execution is initiated or a candidate target PSCell configured for the subsequent CPAC or SCG selective activation procedure.

The above too early Subsequent CPAC or SCG selective activation may be detected by a MN. The MN may indicate the occurrence of too early subsequent CPAC or SCG selective activation to the initial source SN or the corresponding SN (e.g. the SN that manages PSCell#x, or the SN that manages PSCell#y) .

Embodiment 1-4 (too late Subsequent CPAC or SCG selective activation)

The failure type of "too late Subsequent CPAC or SCG selective activation may be defined as follows:

- a UE receives configuration for a subsequent CPAC or SCG selective activation procedure, while a SCG failure occurs before initial CPC execution condition or subsequent CPC execution condition is satisfied; a suitable PSCell different from the PSCell which is treated as source PSCell when the initial CPC execution or subsequent CPC execution is triggered is found based on the measurements reported from the UE.

The above too late Subsequent CPAC or SCG selective activation may be detected by a MN. The MN may indicate the occurrence of too late subsequent CPAC or SCG selective activation to the corresponding SN (e.g. the SN that manages the PSCell which is treated as source PSCell when the initial CPC execution or subsequent CPC execution is triggered) .

Figure 6 illustrates a flowchart of a method related to a subsequent CPAC procedure in accordance with aspects of the present disclosure. The operations of the method may be implemented by a network node as described herein. In some implementations, the network node may be a MN or a source SN which initiates a subsequent CPAC procedure, and may execute a set of instructions to control the function elements of the MN or the source SN to perform the described functions. In some implementations, aspects of operations 602 and 604 may be performed by NE 400, MN 502, or SN 503 as described with reference to Figure 4 or Figure 5. Each of operations 602 and 604 may be performed in accordance with examples as described herein.

At operation 602, the method may include determining, by a network node (denoted as node#1) , that a SCG failure occurs during a subsequent CPAC procedure. For example, node#1 may determine that the SCG failure occurs during the subsequent CPAC procedure based on SCG failure related information, e.g. which is received from the UE.

At operation 604, in case that a SCG failure occurs during a subsequent CPAC procedure, the method may include determining, by node#1, the SCG failure occurs in which one of the following: an initial CPA of the subsequent CPAC procedure; an initial CPC of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure. During the subsequent CPAC procedure, a UE doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution. Moreover, the UE continues evaluating execution conditions of one or more candidate PSCells configured for the subsequent CPAC procedure.

In some implementations, node#1 is a MN initiating the subsequent CPAC procedure. In some other implementations, node#1 is a source SN initiating the subsequent CPAC procedure.

In an implementation, if a selected PSCell (e.g. which is a suitable PSCell selected after occurrence of the SCG failure) is not included in a set (denoted as set#1) of candidate target PSCells provided by node#1, node#1 may determine that wrong candidate target PSCell selection occurs at node#1.

In another implementation, if the selected PSCell is included in set#1 of candidate target PSCells, but not included in another set (denoted as set#2) of candidate target PSCells selected by another network node (denoted as node#2) (e.g. at least one candidate target SN) , node#1 may:

(1) transmit, to node#2, information indicating that wrong candidate target PSCell selection occurs at node#2; or

(2) transmit SCG failure related information to node#2; for example, SCG failure related information may include: cell information of previous PSCell; cell information of failed PSCell; time SCG failure which indicates the time elapsed since the last execution of an RRC reconfiguration message with reconfigurationWithSync for the SCG until the SCG failure; RA-Information; measurement result (s) in MCG and/or measurement result (s) in SCG; and/or failure type. The cell information may include global cell identity, tracking area code of the cell, and/or, PCI and carrier frequency information (e.g. an ARFCN) ; or

(3) transmit cell information of the selected PSCell to node#2.

In some implementations, if the selected PSCell is included in set#2 of candidate target PSCells:

(1) if the SCG failure occurs in the initial CPA, node#1 may determine that one or more wrong CPA execution conditions are set for the initial CPA;

(2) if the SCG failure occurs in the initial CPC, node#1 may determine that one or more wrong CPC execution conditions are set for the initial CPC; and

(3) if the SCG failure occurs in the subsequent CPC, node#1 may:

a) transmit, to node#2, information indicating that one or more wrong CPC execution conditions are set for the subsequent CPC; or

b) transmit the SCG failure related information to node#2; or

c) transmit the cell information of the selected PSCell to node#2.

In some implementations of the method described herein, node#1 may receive, from the UE or another network node (denoted as node#3) , information indicating that the SCG failure occurs in the initial CPA, information indicating that the SCG failure occurs in the initial CPC, or information indicating that the SCG failure occurs in the subsequent CPC. In some implementations, node#1 is an initial source SN (e.g. a node that manages the source PSCell in initial CPAC procedure) or a source SN which initiates the subsequent CPAC procedure, and node#3 is a MN of the subsequent CPAC procedure. In the embodiments of the subject application, a MN of a subsequent CPAC procedure may be a MN initiating the subsequent CPAC procedure or a MN for the subsequent CPAC procedure which is initiated by an initial source SN (i.e. a node that manages a source PSCell in initial CPAC " or "a source SN during the initial CPA or the initial CPC or “a SN managing a source PSCell in the initial CPA or initial CPC” ) .

In some implementations of the method described herein, if node#1 is a MN of the subsequent CPAC procedure, to determine the SCG failure occurs in which one of the initial CPA, the initial CPC, and the subsequent CPC:

(1) if none RRC (connection) reconfiguration complete message (e.g. an RRC connection reconfiguration complete message or an RRC reconfiguration complete message) is received before receiving SCG failure related information, the MN may determine that the SCG failure occurs in the initial CPA or the initial CPC;

(2) if one RRC (connection) reconfiguration complete message is received before receiving the SCG failure related information, the MN may determine time duration between receiving the one RRC reconfiguration complete message and the SCG failure related information; and

(3) if more than one RRC (connection) reconfiguration complete messages are received before receiving the SCG failure related information, the MN may determine that the SCG failure occurs in the subsequent CPC.

In some implementations of the method described herein, after determining the time duration, if the time duration is shorter than or equal to a predefined threshold, the MN may determine that the SCG failure occurs in the initial CPA or the initial CPC; and if the time duration is longer than the predefined threshold, the MN may determine that the SCG failure occurs in the subsequent CPC.

In some implementations of the method described herein, the MN may transmit, to a source SN initiating the subsequent CPAC procedure, information indicating that the SCG failure occurs in the initial CPA, information indicating that the SCG failure occurs in the initial CPC, or information indicating that the SCG failure occurs in the subsequent CPC.

In some implementations of the method described herein, node#1 may determine that the SCG failure occurs during the subsequent CPAC procedure in response to detecting an event. The event may occur at least once (e.g. more than once) in the subsequent CPAC procedure. The event may be one of the following:

(1) the UE performs a CPC execution from one PSCell (e.g. PSCell#a) to another PSCell (e.g. PSCell#b) successfully, but within a predefined limited time the UE performs a CPC execution from PSCell#b to an additional PSCell (e.g. PSCell#c) successfully, i.e., the failure type of "wrong Subsequent CPAC or SCG selective activation" in Embodiment 1-2;

(2) the UE performs the CPC execution from one PSCell (e.g. PSCell#a) to another PSCell (e.g. PSCell#b) , but the CPC execution is not successful or the SCG failure occurs shortly after the CPC execution is successful, wherein the one PSCell (e.g. PSCell#a) is a suitable PSCell based on measurements reported from the UE, i.e., the failure type of "too early Subsequent CPAC or SCG selective activation" in Embodiment 1-3; and

(3) the UE receives configuration information for the subsequent CPAC procedure, while the SCG failure occurs before one or more execution conditions of the initial CPC or the subsequent CPC are fulfilled, i.e., the failure type of "too late Subsequent CPAC or SCG selective activation" in Embodiment 1-4.

In some implementations of the method described herein, if node#1 is a MN of the subsequent CPAC procedure, the MN may generate a set of trigger conditions (denoted as trigger condition set#1) related to a successful report, and transmit trigger condition set#1 to the UE. Trigger condition set#1 may be for at least one of "the initial CPA" or "one or more subsequent CPCs" of the subsequent CPAC procedure, or for at least one of "the initial CPC" or "the one or more subsequent CPCs" . Trigger condition set#1 for the one or more subsequent CPCs may include different or common trigger conditions for each of the one or more subsequent CPCs. Trigger condition set#1 may be associated with timer T310 or timer T312. The successful report may be a SPR, or may be a new report introduced for a PCell change with PSCell change procedure, or may be a new report introduced for a subsequent CPAC procedure.

In some implementations of the method described herein, if node#1 is a MN of the subsequent CPAC procedure, the MN may receive, from an initial source SN (e.g. a node that manages the source PSCell in an initial CPAC procedure) , a set of trigger conditions (denoted as trigger condition set#2) related to a successful report for the initial CPC, and transmit this set of trigger conditions to the UE. Trigger condition set#2 may be associated with timer T310 or timer T312.

In some implementations of the method described herein, if node#1 is a MN of the subsequent CPAC procedure, the MN may receive at least one of the following from a candidate target SN, and then transmit at least one of the received sets of trigger conditions to the UE:

(1) A set of trigger conditions (denoted as trigger condition set#3) related to a successful report, which is for at least one of "the initial CPA" or "one or more subsequent CPCs" of the subsequent CPAC procedure" , or for at least one of "the initial CPC" or "the one or more subsequent CPCs" . Trigger condition set#3 for the one or more subsequent CPCs may include different or common trigger conditions for each of the one or more subsequent CPCs. Trigger condition set#3 may be associated with timer T304. Trigger condition set#3 may be generated by a candidate target SN and transmitted to the MN.

(2) A set of trigger conditions (denoted as trigger condition set#4) related to the successful report for the one or more subsequent CPCs. Trigger condition set#4 for the one or more subsequent CPCs may include different or common trigger conditions for each of the one or more subsequent CPCs. Trigger condition set#4 may be associated with timer T310 or timer T312.

In some implementations of the method described herein, if node#1 is a source SN initiating the subsequent CPAC procedure, the source SN may generate a set of trigger conditions (denoted as trigger condition set#5) related to a successful report for the initial CPC, and transmit this set of trigger conditions to a MN or the UE. The successful report may be a SPR, or may be a new report introduced for a PCell change with PSCell change procedure, or may be a new report introduced for a subsequent CPAC procedure. Trigger condition set#5 may be associated with timer T310 or timer T312.

In some implementations of the method described herein, if common trigger conditions related to the successful report are generated for each of the one or more subsequent CPCs, node#1 may transmit, to the UE, information indicating that trigger conditions related to the successful report for each of the one or more subsequent CPCs are common. For example, if node#1 is a MN of the subsequent CPAC procedure, the MN may send, to the UE, an indication to indicate that the T310 related trigger condition is common for each of the one or more subsequent CPCs. Or, the MN may send, to the UE, an indication to indicate that the T312 related trigger condition is common for each of the one or more subsequent CPCs. In some implementations of the method described herein, if node#1 is a MN of the subsequent CPAC procedure, the MN may send, to the UE, an indication to indicate that the T310 related trigger condition of a SPR or a new report is common for both initial CPAC and anyone of subsequent CPC (s) . Or, the MN may send, to the UE, an indication to indicate that the T312 related trigger condition of the SPR or the new report is common for both initial CPAC and anyone of subsequent CPC (s) . The new report may be a report introduced for a PCell change with PSCell change procedure, or may be a report introduced for a subsequent CPAC procedure.

In some implementations of the method described herein, if node#1 is the MN of the subsequent CPAC procedure, the MN may receive a successful report from the UE, and determine the successful report is for which one of the initial CPA, the initial CPC, and the subsequent CPC. The successful report may be a SPR, or may be a new report introduced for a PCell change with PSCell change procedure, or may be a new report introduced for a subsequent CPAC procedure.

In some implementations of the method described herein, if node#1 is the MN of the subsequent CPAC procedure, the MN may receive, from the UE, information indicating that the successful report is for the initial CPA, information indicating that the successful report is for the initial CPC, or information indicating that the successful report is for the subsequent CPC.

In some implementations of the method described herein, if node#1 is the MN of the subsequent CPAC procedure, to determine the successful report is for which one of the initial CPA, the initial CPC, and the subsequent CPC:

(1) if only one RRC (connection) reconfiguration complete message (e.g. an RRC connection reconfiguration complete message or an RRC reconfiguration complete message) is received before receiving the successful report, the MN may determine that the successful report is for the initial CPA or the initial CPC;

(2) if two RRC (connection) reconfiguration complete messages are received before receiving the successful report, the MN may determine whether a SCG failure information message is received; and

(3) if more than two RRC (connection) reconfiguration complete messages are received before receiving the successful report, the MN may determine that the successful report is for the subsequent CPC.

In some implementations of the method described herein, if node#1 is the MN of the subsequent CPAC procedure, during determining whether the SCG failure information message is received, if the SCG failure information message is received, the MN may determine that the successful report is for the initial CPA or the initial CPC, and if the SCG failure information message is not received, the MN may determine that the successful report is for the subsequent CPC.

In some implementations of the method described herein, if node#1 is the MN of the subsequent CPAC procedure:

(1) if the successful report is for the initial CPA or the initial CPC:

a) if the subsequent CPAC procedure is initiated by the MN, the MN may transmit the successful report to an initial source SN (e.g. a node that manages the source PSCell in an initial CPAC procedure) ; and

b) if the subsequent CPAC procedure is initiated by the source SN, the MN may transmit the successful report to the source SN; and

(2) if the successful report is for the subsequent CPC, the MN may transmit the successful report to a target SN managing a target PSCell included in the successful report.

It should be noted that the method described in Figure 6 describes possible implementations, and that the operations and the steps may be rearranged or otherwise eliminated or modified and that other implementations are possible, without departing from the spirit and scope of the disclosure.

Figure 7 illustrates another flowchart of a method related to a subsequent CPAC procedure in accordance with aspects of the present disclosure. The operations of the method may be implemented by a UE as described herein. In some implementations, the UE may execute a set of instructions to control the function elements of the UE to perform the described functions. In some implementations, aspects of operations 702 and 704 may be performed by UE 200 or UE 501 as described with reference to Figure 2 or Figure 5. Each of operations 702 and 704 may be performed in accordance with examples as described herein.

At operation 702, the method may include determining, by a UE, that a SCG failure occurs during a subsequent CPAC procedure. At operation 704, the method may include transmitting, by the UE, information indicating the SCG failure occurs in which one of the following: an initial CPA of the subsequent CPAC procedure; an initial CPC of the subsequent CPAC procedure; and a subsequent CPC of the subsequent CPAC procedure. During the subsequent CPAC procedure, a UE doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution. Moreover, the UE continues evaluating execution conditions of one or more candidate PSCells configured for the subsequent CPAC procedure.

In some implementations of the method described herein, the UE may determine that the SCG failure occurs during the subsequent CPAC procedure in response to detecting an event. The event may occur at least once in the subsequent CPAC procedure. The event may be one of the following:

(1) the UE performs a CPC execution from one PSCell (e.g. PSCell#a) to another PSCell (e.g. PSCell#b) successfully, but within a predefined limited time the UE performs a CPC execution from the another PSCell (e.g. PSCell#b) to an additional PSCell (e.g. PSCell#c) successfully, i.e., the failure type of "wrong Subsequent CPAC or SCG selective activation" in Embodiment 1-2;

(3) the UE receives configuration information for the subsequent CPAC procedure, while the SCG failure occurs before one or more executions condition of the initial CPC or the subsequent CPC are fulfilled, i.e., the failure type of "too late Subsequent CPAC or SCG selective activation" in Embodiment 1-4.

In some implementations of the method described herein, the UE may receive a set of trigger conditions related to a successful report, and generate a successful report, e.g. due to fulfillment of the set of trigger conditions. The successful report may be a SPR, or may be a new report introduced for a PCell change with PSCell change procedure, or may be a new report introduced for a subsequent CPAC procedure. The set of trigger conditions may be associated with at least one of timer T310, timer T312, or timer T304. The set of trigger conditions may include at least one of the following:

(1) A set of trigger conditions (e.g. trigger condition set#1 or trigger condition set#3) for at least one of "the initial CPA" or "one or more subsequent CPCs" of the subsequent CPAC procedure, or for at least one of "the initial CPC" or "the one or more subsequent CPCs" . Trigger condition set#1 may be generated by a MN, and then the MN transmits trigger condition set#1 to the UE. Trigger condition set#3 may be generated by a candidate target SN, the candidate target SN transmits trigger condition set#3 to the MN, and then the MN transmits trigger condition set#3 to the UE.

(2) A set of trigger conditions (e.g. trigger condition set#2 or trigger condition set#5) for the initial CPC. Trigger condition set#2 may be generated by an initial source SN (e.g. a node that manages the source PSCell in an initial CPAC procedure) , and transmitted to the UE by the initial source SN or via a MN. Trigger condition set#5 may be generated by a candidate target SN and transmitted to the MN, and then the MN transmits trigger condition set#5 to the UE.

(3) A set of trigger conditions (e.g. trigger condition set#4) for the one or more subsequent CPCs. Trigger condition set#4 may be generated by a candidate target SN and transmitted to the MN, and then the MN transmits trigger condition set#4 to the UE.

In an implementation, if the set of trigger conditions includes T310 related trigger condition, when the ratio between the value of the elapsed time of the timer T310 of current source PSCell and the configured value of the timer T310 configured for this current source PSCell is greater than the configured T310 related threshold (e.g. a percentage value) , the UE may consider that the set of trigger conditions is fulfilled, and then generate a successful report.

In another implementation, if the set of trigger conditions includes T304 related trigger condition, when the ratio between the value of the elapsed time of the timer T304 of target PSCell and the configured value of the timer T304 configured for this target PSCell is greater than the configured T304 related threshold (e.g. a percentage value) , the UE may consider that the set of trigger conditions is fulfilled, and then generate a successful report.

In another implementation, if the set of trigger conditions includes T312 related trigger condition, when the ratio between the value of the elapsed time of the timer T312 of current source PSCell and the configured value of the timer T312 configured for this current source PSCell is greater than the configured T312 related threshold (e.g. a percentage value) , the UE may consider that the set of trigger conditions is fulfilled, and then generate a successful report.

In some implementations of the method described herein, the UE may transmit, to the MN, information indicating that the successful report is for the initial CPA, information indicating that the successful report is for the initial CPC, or information indicating that the successful report is for the subsequent CPC.

It should be noted that the method described in Figure 7 describes possible implementations, and that the operations and the steps may be rearranged or otherwise eliminated or modified and that other implementations are possible, without departing from the spirit and scope of the disclosure.

In accordance with some aspects of the present disclosure, operations of a method related to a subsequent CPAC procedure may be implemented by a candidate target SN as described herein. In some implementations, the candidate target SN may execute a set of instructions to control the function elements of the candidate target SN to perform the described functions.

In some implementations of the method described herein, the method may include determining, by a candidate target SN, which one of the following occurs during a subsequent CPAC procedure: wrong candidate target PSCell selection at the candidate target SN; and one or more wrong CPC execution conditions set at the candidate target SN. During the subsequent CPAC procedure, a UE doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution. Moreover, the UE continues evaluating execution conditions of one or more candidate PSCells configured for the subsequent CPAC procedure.

In some implementations, the one or more wrong CPC execution conditions include one or more wrong CPC execution conditions for at least one subsequent CPC of the subsequent CPAC procedure.

In some implementations of the method described herein, the candidate target SN may receive an indication from a network node, which indicates one of the following:

(1) at least one wrong candidate target PSCell is selected at the candidate target SN;

(2) at least one wrong CPC execution condition is set at the candidate target SN;

(3) SCG failure related information; and

(4) cell information of a PSCell selected during the subsequent CPAC procedure.

In some implementations, the indication is received by the candidate target SN in case that:

(1) the selected PSCell is included in a set (e.g. set#1) of candidate target PSCells provided by a network node (e.g. node#1) , but not included in another set (e.g. set#2) of candidate target PSCells selected by the candidate target SN. In some implementations, node#1 is a MN initiating the subsequent CPAC procedure or a source SN initiating the subsequent CPAC procedure.

(2) the selected PSCell is included in another set (e.g. set#2) of candidate target PSCells selected by the candidate target SN.

In some implementations of the method described herein, the subsequent CPAC procedure includes: an initial CPA; an initial CPC; and one or more subsequent CPCs.

In some implementations of the method described herein, the candidate target SN may generate a set of trigger conditions (e.g. trigger condition set#4) related to a successful report for the one or more subsequent CPCs, and transmit the set of trigger conditions of a SPR or new report (s) to a MN. The successful report may be a SPR, or may be a new report introduced for a PCell change with PSCell change procedure, or may be a new report introduced for a subsequent CPAC procedure. This set of trigger conditions may be associated with timer T310 or timer T312. This set of trigger conditions for one or more subsequent CPCs may include different or common trigger conditions for each of the one or more subsequent CPCs.

In some implementations of the method described herein, the candidate target SN may generate a set of trigger conditions (e.g. trigger condition set#3) related to a successful report, and transmit this set of trigger conditions of a SPR or new report (s) to a MN. The successful report may be a SPR, or may be a new report introduced for a PCell change with PSCell change procedure, or may be a new report introduced for a subsequent CPAC procedure. This set of trigger conditions may be for at least one of "the initial CPA" or "one or more subsequent CPCs" , or for at least one of "the initial CPC" or "one or more subsequent CPCs" , and may be associated with timer T304. This set of trigger conditions for one or more subsequent CPCs may include different or common trigger conditions for each of the one or more subsequent CPCs. For example, this set of trigger conditions (e.g. T304 related Trigger condition of the SPR or the new report (s) ) for each of the one or more subsequent CPCs may be the same or different. In some implementations of the method described herein, this set of trigger conditions (e.g. T304 related trigger condition of a SPR or new report (s) ) for initial CPAC and anyone of subsequent CPC (s) may be the same or different.

In some implementations of the method described herein, if common trigger conditions related to the successful report are generated for each of the one or more subsequent CPCs, the candidate target SN may transmit, to the UE, information indicating that trigger conditions related to the successful report for each of the one or more subsequent CPCs are common, via a MN of the subsequent CPAC procedure.

The following text describes specific embodiments of the flowcharts as shown and illustrated above, i.e., Embodiment 2 and Embodiment 3.

Embodiment 2 (MRO for a failure case)

Embodiment 2-1 (MRO for a failure case in a MN initiated Subsequent CPAC or SCG selective activation)

In Embodiment 2-1, for a MN initiated Subsequent CPAC or SCG selective activation procedure, a MN decides or generates execution condition (s) for initial CPAC of the Subsequent CPAC procedure, and the MN provides the list of candidate target PSCell (s) to one or more (candidate) target SNs. Embodiment 2-1 assumes that each (candidate) target SN decides or generates execution conditions for one or more subsequent CPCs of the Subsequent CPAC procedure. In Embodiment 2-1, a SCG failure (e.g. CPC/CPA execution is not successful or an SCG failure occurs shortly after a successful CPC/CPA execution) may occur in initial CPAC or subsequent CPC of the Subsequent CPAC procedure.

In an example of Embodiment 2-1, if a SCG failure occurs in an initial CPAC of the Subsequent CPAC procedure, MRO analysis or optimization at the network side may be as follows.

AMN receives SCG failure related information from a UE via the SCG failure information message. Then, the MN selects a suitable PSCell after the SCG failure, e.g. the MN selects a suitable PSCell for SCG reconfiguration, and the MN performs failure analysis:

(1) If the suitable PSCell is one of the candidate target PSCells provided by the MN to a (candidate) target SN, but not one of the candidate target PSCells selected by the (candidate) target SN, the MN may perform one of following two manners:

a) The MN finds or detects that it is wrong candidate target PSCell selection at the (candidate) target SN. The MN may indicate to the (candidate) target SN that the wrong candidate target PSCell (s) are selected or prepared by the (candidate) target SN, e.g. via the SCG FAILURE INFORMATION REPORT message, optionally, MN may forward SCG failure related information to the (candidate) target SN, e.g. via the SCG FAILURE INFORMATION REPORT message. Then, the (candidate) target SN may modify the selected or prepared candidate target PSCell (s) .

b) The MN may forward SCG failure related information and cell information of the MN selected suitable PSCell to the (candidate) target SN, e.g. via the SCG FAILURE INFORMATION REPORT message; the (candidate) target SN finds or detects that it is wrong candidate target PSCell selection at the (candidate) target SN. Then, the (candidate) target SN may modify the selected or prepared candidate target PSCell (s) .

(2) If the suitable PSCell is not one of the candidate target PSCells provided by the MN to a (candidate) target SN, the MN finds or detects that it is wrong candidate PSCell list selection at the MN. The MN may modify its provided/selected list of candidate target PSCell (s) .

(3) If the suitable PSCell is one of the candidate target PSCells selected or prepared by the (candidate) target SN, MN finds or detects that it is wrong CPAC execution condition (s) setting or decision at MN; MN may modify the execution condition (s) for initial CPAC.

In another example of Embodiment 2-1, if a SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure, MRO analysis or optimization at the network side may be as follows.

AMN may receive SCG failure related information from the UE via the SCG failure information message. Then, the MN may select a suitable PSCell after the SCG failure, e.g. the MN selects a suitable PSCell for SCG reconfiguration, and performs failure analysis:

(1) If the suitable PSCell is one of the candidate target PSCells provided by MN to a (candidate) target SN, but not one of the candidate target PSCells selected by the (candidate) target SN, the MN may perform one of following two manners:

(3) If the suitable PSCell is one of the candidate target PSCells selected or prepared by the (candidate) target SN, the MN may perform one of following two manners:

a) The MN finds or detects that it is wrong CPAC execution condition (s) for subsequent CPC setting or decision at the (candidate) target SN. The MN may indicate to the (candidate) target SN that wrong CPAC execution condition (s) for subsequent CPC are set or decided by the (candidate) target SN, e.g. via the SCG FAILURE INFORMATION REPORT message. Optionally, the MN may forward SCG failure related information to the (candidate) target SN, e.g. via the SCG FAILURE INFORMATION REPORT message. Then, the (candidate) target SN may modify the execution condition (s) for subsequent CPC.

b) The MN may forward SCG failure related information and cell information of the MN selected suitable PSCell to the (candidate) target SN, e.g. via the SCG FAILURE INFORMATION REPORT message. The (candidate) target SN may find or detect that it is wrong CPAC execution condition (s) for subsequent CPC setting or decision at the (candidate) target SN. Then, the (candidate) target SN may modify the execution condition (s) for subsequent CPC.

Based on above descriptions in Embodiment 2-1, MRO analysis or optimization at the network side for initial CPAC and subsequent CPC of the Subsequent CPAC procedure may be different (e.g. for the case that if the suitable PSCell is one of the candidate target PSCells selected or prepared by the (candidate) target SN) . To enable the network to perform right MRO handling (to let a MN know whether SCG failure occurs in initial CPAC or subsequent CPC of the Subsequent CPAC procedure) , there may be following two options:

(1) Option#X: (UE-based solution)

a) A UE indicates a MN about whether a SCG failure occurs in initial CPAC or subsequent CPC of the Subsequent CPAC procedure, e.g. the UE includes an indication to indicate SCG failure occurs in initial CPAC or subsequent CPC of the Subsequent CPAC procedure in the SCG failure information message. After the MN receives the SCG failure information message which includes the indication, the MN may send an indication explicitly to the initial source SN, or the MN may send the SCG failure related information which includes the indication to the initial source SN.Also, the MN may send an indication explicitly to the (candidate) target SN, or the MN may send the SCG failure related information which includes the indication to the (candidate) target SN. For instance, an indication to indicate that the SCG failure occurs in initial CPAC or in subsequent CPC of the Subsequent CPAC procedure may be sent from the MN to the initial source SN or the (candidate) target SN, or an indication to indicate that the SCG failure occurs in initial CPAC or in subsequent CPC of the Subsequent CPAC procedure may be included in the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message from the MN to the initial source SN or the (candidate) target SN. Also, the UE prioritizes to report the measurement results of one or more candidate target PSCells that evaluated for subsequent CPC of the Subsequent CPAC procedure.

(2) Option#Y: (network-based solution)

a) If none RRC (connection) reconfiguration complete message (e.g. an RRC connection reconfiguration complete message or an RRC reconfiguration complete message) is received before receiving SCG failure information message from a UE, a MN knows the received SCG failure information message is for initial CPAC of the Subsequent CPAC procedure. Optionally, the MN may indicate to the initial source SN that the latest SCG failure occurs in the initial CPAC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. Also, the MN may indicate to the (candidate) target SN that the latest SCG failure occurs in the initial CPAC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. For instance, an indication to indicate that the SCG failure occurs in the initial CPAC of the Subsequent CPAC procedure may be included in the SCG FAILURE INFORMATION REPORT message or the new Xn or X2 message.

b) If one RRC (connection) reconfiguration complete message is received before receiving SCG failure information message from the UE, the MN decides whether the SCG failure occurs in initial CPAC or subsequent CPC of the Subsequent CPAC procedure based on time duration between RRC (connection) reconfiguration complete message and SCG failure information message. For example, if the time duration is shorter than a predefined threshold, the MN decides that the received SCG failure information message is for initial CPAC of the Subsequent CPAC procedure (e.g. for the case that an RLF occurring shortly after a successfully initial CPAC execution) , optionally, the MN may indicate to the initial source SN that the latest SCG failure occurs in initial CPAC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message, also, the MN may indicate to the (candidate) target SN that the latest SCG failure occurs in initial CPAC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. For instance, an indication to indicate that the SCG failure occurs in initial CPAC of the Subsequent CPAC procedure may be included in the SCG FAILURE INFORMATION REPORT message or the new Xn or X2 message. If the time duration is longer than a predefined threshold, the MN decides that the received SCG failure information message is for subsequent CPC of the Subsequent CPAC procedure (e.g. for the case that the subsequent CPC execution fails) , optionally, the MN may indicate to the initial source SN that the latest SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message, also, the MN may indicate to the (candidate) target SN that the latest SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. For instance, an indication to indicate that the SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure may be included in the SCG FAILURE INFORMATION REPORT message or the new Xn or X2 message.

c) If more than one RRC (connection) reconfiguration complete messages are received before receiving SCG failure information message from the UE, the MN decides that the received SCG failure information message is for subsequent CPC of the Subsequent CPAC procedure, optionally, the MN may indicate to the initial source SN that the latest SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message, also, the MN may indicate to the (candidate) target SN that the latest SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. For instance, an indication to indicate that the SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure may be included in the SCG FAILURE INFORMATION REPORT message or the new Xn or X2 message.

Based on Option#X or Option#Y, the network can perform corresponding MRO analysis or optimization for initial CPAC or subsequent CPC of the Subsequent CPAC procedure e.g. according to above descriptions in Embodiment 2-1.

Embodiment 2-2 (MRO for failure case in a SN initiated Subsequent CPAC or SCG selective activation)

As described above, in a SN initiated Subsequent CPAC or SCG selective activation procedure, a SN which initiates the Subsequent CPAC or SCG selective activation procedure is "an initial source SN (i.e. a node that manages a source PSCell in initial CPAC, or a source SN during the initial CPA or the initial CPC, or a SN managing a source PSCell in the initial CPA or initial CPC) .

In Embodiment 2-2, for a SN initiated Subsequent CPAC or SCG selective activation procedure, an initial source SN (the node that manages the source PSCell in initial CPAC procedure) or a SN which initiates Subsequent CPAC or SCG selective activation procedure decides or generates execution condition (s) for initial CPAC of the Subsequent CPAC procedure. The initial source SN or the SN which initiates Subsequent CPAC or SCG selective activation procedure provides the list of candidate target PSCell (s) to one or more (candidate) target SNs via a MN. Each (candidate) target SN decides or generates execution conditions for one or subsequent CPCs of the Subsequent CPAC procedure. In Embodiment 2-2, a SCG failure (e.g. CPC/CPA execution is not successful or an SCG failure occurs shortly after a successful CPC/CPA execution) may occur in initial CPAC or subsequent CPC of the Subsequent CPAC procedure.

In an example of Embodiment 2-2, if a SCG failure occurs in initial CPC of the Subsequent CPAC procedure, MRO analysis or optimization at the network side may be as follows.

A MN receives SCG failure related information from a UE via the SCG failure information message. Then, the MN performs initial analysis, and sends SCG failure related information to the initial source SN or the SN which initiates Subsequent CPAC procedure. Optionally, the MN also sends cell information of suitable PSCell to the initial source SN or the SN which initiates Subsequent CPAC procedure if the MN selects the suitable PSCell after the SCG failure, or initial source SN or the SN which initiates Subsequent CPAC procedure selects the suitable PSCell after receiving SCG failure related information.

(1) If the suitable PSCell is one of the candidate target PSCells provided by the initial source SN or the SN which initiates Subsequent CPAC procedure to a (candidate) target SN via the MN, but not one of the candidate target PSCells selected by the (candidate) target SN, the MN may perform one of following two manners:

a) the initial source SN or the SN which initiates Subsequent CPAC procedure finds or detects that it is wrong candidate target PSCell selection at the (candidate) target SN. The initial source SN or the SN which initiates Subsequent CPAC procedure may indicate to the (candidate) target SN that the wrong candidate target PSCell (s) are selected or prepared by the (candidate) target SN directly (e.g. via a new message or via the SCG FAILURE INFORMATION REPORT message) or via the MN (the initial source SN or the SN which initiates Subsequent CPAC procedure may also indicate information of (candidate) target SN (e.g. Node ID of the (candidate) target SN or cell information of the candidate target PSCell) where the wrong candidate target PSCell (s) are selected or prepared to the MN. Thus, the MN can indicate to the (candidate) target SN that the wrong candidate target PSCell (s) are selected or prepared, e.g. via the SCG FAILURE INFORMATION REPORT message) . Optionally, the MN or the initial source SN or the SN which initiates Subsequent CPAC procedure may forward SCG failure related information to the (candidate) target SN, e.g. via a new message or via the SCG FAILURE INFORMATION REPORT message. Then, the (candidate) target SN may modify the selected or prepared candidate target PSCell (s) .

b) The initial source SN or the SN which initiates Subsequent CPAC procedure may indicate information of (candidate) target SN (e.g. Node ID of the (candidate) target SN or cell information of the candidate target PSCell) where the wrong candidate target PSCell (s) may be selected or prepared to the MN. Then, the MN may forward SCG failure related information and cell information of the suitable PSCell (i.e. which is selected by the MN or indicated by the initial source SN to the MN if the initial source SN selects the suitable PSCell or indicated by the SN which initiates Subsequent CPAC procedure to the MN if the SN which initiates Subsequent CPAC procedure selects the suitable PSCell) to the indicated (candidate) target SN, e.g. via the SCG FAILURE INFORMATION REPORT message. The (candidate) target SN finds or detects that it is wrong candidate target PSCell selection at the (candidate) target SN. Then, the (candidate) target SN may modify the selected or prepared candidate target PSCell (s) .

(2) If the suitable PSCell is not one of the candidate target PSCells provided by the initial source SN or the SN which initiates Subsequent CPAC procedure to a (candidate) target SN via the MN, the initial source SN finds or detects that it is wrong candidate PSCell list selection. The initial source SN or the SN which initiates Subsequent CPAC procedure may modify its provided/selected list of candidate target PSCell (s) .

(3) If the suitable PSCell is one of the candidate target PSCells selected or prepared by the (candidate) target SN, the initial source SN or the SN which initiates Subsequent CPAC procedure finds or detects that it is wrong CPAC execution condition (s) setting or decision at the initial source SN or the SN which initiates Subsequent CPAC procedure. The initial source SN or the SN which initiates Subsequent CPAC procedure may modify the execution condition (s) for initial CPAC of the Subsequent CPAC procedure.

In another example of Embodiment 2-2, if SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure, MRO analysis or optimization at the network side may be as follows.

AMN receives SCG failure related information from the UE via the SCG failure information message. The MN performs initial analysis, and sends SCG failure related information to the initial source SN or the SN which initiates Subsequent CPAC procedure. Optionally, the MN also sends cell information of suitable PSCell to the initial source SN or the SN which initiates Subsequent CPAC procedure if the MN selects the suitable PSCell, or initial source SN or the SN which initiates Subsequent CPAC procedure selects the suitable PSCell after receiving SCG failure related information.

(1) If the suitable PSCell is one of the candidate target PSCells provided by the initial source SN or the SN which initiates Subsequent CPAC procedure to a (candidate) target SN via the MN, but not one of the candidate target PSCells selected by the (candidate) target SN, the initial source SN or the SN which initiates Subsequent CPAC procedure may perform one of following two manners:

a) The initial source SN or the SN which initiates Subsequent CPAC procedure finds or detects that it is wrong candidate target PSCell selection at the (candidate) target SN.The initial source SN or the SN which initiates Subsequent CPAC procedure may indicate to the (candidate) target SN that the wrong candidate target PSCell (s) are selected or prepared by the (candidate) target SN directly (e.g. via a new message or via the SCG FAILURE INFORMATION REPORT message) or via the MN (the initial source SN or the SN which initiates Subsequent CPAC procedure may also indicate information of (candidate) target SN (e.g. Node ID of the (candidate) target SN or cell information of the candidate target PSCell) where the wrong candidate target PSCell (s) are selected or prepared to the MN, and thus, the MN can indicate to the (candidate) target SN that the wrong candidate target PSCell (s) are selected or prepared, e.g. via the SCG FAILURE INFORMATION REPORT message) . Optionally, the MN or the initial source SN or the SN which initiates Subsequent CPAC procedure may forward SCG failure related information to the (candidate) target SN, e.g. via a new message or via the SCG FAILURE INFORMATION REPORT message. Then, the (candidate) target SN may modify the selected or prepared candidate target PSCell (s) .

b) The initial source SN or the SN which initiates Subsequent CPAC procedure may indicate information of (candidate) target SN (e.g. Node ID of the (candidate) target SN or cell information of the candidate target PSCell) where the wrong candidate target PSCell (s) may be selected or prepared to the MN. Then, the MN may forward SCG failure related information and cell information of the suitable PSCell (i.e. which is selected by the MN or indicated by the initial source SN to the MN if initial source SN selects the suitable PSCell or indicated by the SN which initiates Subsequent CPAC procedure to the MN if the SN which initiates Subsequent CPAC procedure selects the suitable PSCell) to the indicated (candidate) target SN, e.g. via the SCG FAILURE INFORMATION REPORT message. The (candidate) target SN finds or detects that it is wrong candidate target PSCell selection at the (candidate) target SN. Then, the (candidate) target SN may modify the selected or prepared candidate target PSCell (s) .

(3) If the suitable PSCell is one of the candidate target PSCells selected or prepared by the (candidate) target SN, the initial source SN or the SN which initiates Subsequent CPAC procedure may perform one of following two manners:

a) The initial source SN or the SN which initiates Subsequent CPAC procedure finds or detects that it is wrong CPAC execution condition (s) for subsequent CPC setting or decision at the (candidate) target SN. The initial source SN or the SN which initiates Subsequent CPAC procedure may indicate to the (candidate) target SN that the wrong CPAC execution condition (s) for subsequent CPC of the Subsequent CPAC procedure are set or generated at the (candidate) target SN directly (e.g. via a new message or via the SCG FAILURE INFORMATION REPORT message) or via the MN (the initial source SN or the SN which initiates Subsequent CPAC procedure may indicate information of (candidate) target SN (e.g. Node ID of the (candidate) target SN or cell information of the candidate target PSCell) where the wrong CPAC execution condition (s) for subsequent CPC are set or generated to the MN.Thus, the MN can indicate to the (candidate) target SN that the wrong CPAC execution condition (s) for subsequent CPC of the Subsequent CPAC procedure are set or generated, e.g. via the SCG FAILURE INFORMATION REPORT message) . Optionally, the MN may forward SCG failure related information to the (candidate) target SN, e.g. via the SCG FAILURE INFORMATION REPORT message. Then, the (candidate) target SN may modify the execution condition (s) for subsequent CPC of the Subsequent CPAC procedure.

b) The initial source SN or the SN which initiates Subsequent CPAC procedure may indicate information of (candidate) target SN (e.g. Node ID of the (candidate) target SN or cell information of the candidate target PSCell) where the wrong CPAC execution condition (s) for subsequent CPC may be set or generated to the MN. Then, the MN may forward SCG failure related information and cell information of the suitable PSCell (i.e. which is selected by MN or indicated by the initial source SN to the MN if initial source SN selects the suitable PSCell or indicated by the SN which initiates Subsequent CPAC procedure to the MN if the SN which initiates Subsequent CPAC procedure selects the suitable PSCell) to the indicated (candidate) target SN, e.g. via the SCG FAILURE INFORMATION REPORT message. The (candidate) target SN finds or detects that it is wrong CPAC execution condition (s) for subsequent CPC setting or decision at the (candidate) target SN. Then, the (candidate) target SN may modify the execution condition (s) for subsequent CPC of the Subsequent CPAC procedure.

Based on above descriptions in Embodiment 2-2, MRO analysis or optimization at the network side for initial CPAC and subsequent CPC of the Subsequent CPAC procedure may be different (e.g. for the case that if the suitable PSCell is one of the candidate target PSCells selected or prepared by the (candidate) target SN) . To enable the network to perform right MRO handling (to let a MN or the initial source SN or the SN which initiates Subsequent CPAC procedure know whether SCG failure occurs in initial CPAC or subsequent CPC of the Subsequent CPAC procedure) , there may be following two options:

(1) Option#E: (UE-based solution)

a) A UE indicates the network about whether SCG failure occurs in initial CPAC or subsequent CPC of the Subsequent CPAC procedure, e.g. the UE includes an indication to indicate SCG failure occurs in initial CPAC or subsequent CPC of the Subsequent CPAC procedure in the SCG failure information message. After a MN receives the SCG failure information message which includes the indication, the MN may send the indication explicitly to the initial source SN or the SN which initiates Subsequent CPAC procedure, or the MN may send the SCG failure related information which includes the indication to the initial source SN or the SN which initiates Subsequent CPAC procedure. Also, the MN may send the indication explicitly to the (candidate) target SN, or the MN may send the SCG failure related information which includes an indication to the (candidate) target SN. For instance, an indication to indicate that the SCG failure occurs in initial CPAC or in subsequent CPC of the Subsequent CPAC procedure may be sent from the MN to the initial source SN or the SN which initiates Subsequent CPAC procedure or the (candidate) target SN, or an indication to indicate that the SCG failure occurs in initial CPAC or in subsequent CPC of the Subsequent CPAC procedure may be included in the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message from the MN to the initial source SN or the SN which initiates Subsequent CPAC procedure or the (candidate) target SN. Also, the UE prioritizes to report the measurement results of one or more candidate target PSCells that evaluated for subsequent CPC of the Subsequent CPAC procedure.

(2) Option#F: (network-based solution) A MN indicates to the initial source SN or the SN which initiates Subsequent CPAC procedure about whether SCG failure occurs in initial CPAC or subsequent CPC of the Subsequent CPAC procedure. For example:

a) If none RRC (connection) reconfiguration complete message (e.g. an RRC connection reconfiguration complete message or an RRC reconfiguration complete message) is received before receiving SCG failure information message from the UE, the MN knows that the received SCG failure information message is for initial CPAC of the Subsequent CPAC procedure. The MN indicates the initial source SN or the SN which initiates Subsequent CPAC procedure that the latest SCG failure occurs in initial CPAC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. Also, the MN may indicate to the (candidate) target SN that the latest SCG failure occurs in initial CPAC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. For instance, an indication to indicate that the SCG failure occurs in initial CPAC of the Subsequent CPAC procedure may be included in the SCG FAILURE INFORMATION REPORT message or the new Xn or X2 message.

b) If one RRC (connection) reconfiguration complete message is received before receiving SCG failure information message from the UE, the MN decides whether the SCG failure occurs in initial CPAC or subsequent CPC of the Subsequent CPAC procedure based on time duration between RRC (connection) reconfiguration complete message and SCG failure information message. For example, if the time duration is shorter than a predefined threshold, the MN decides that the received SCG failure information message is for initial CPAC of the Subsequent CPAC procedure (e.g. for the case that an RLF occurring shortly after a successfully initial CPAC execution) . The MN may indicate to the initial source SN or the SN which initiates Subsequent CPAC procedure that the latest SCG failure occurs in initial CPAC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. Also, the MN may indicate to the (candidate) target SN that the latest SCG failure occurs in initial CPAC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. For instance, an indication to indicate that the SCG failure occurs in initial CPAC of the Subsequent CPAC procedure may be included in the SCG FAILURE INFORMATION REPORT message or the new Xn or X2 message. If the time duration is longer than a predefined threshold, the MN decides that the received SCG failure information message is for subsequent CPC of the Subsequent CPAC procedure. The MN may indicate to the initial source SN or the SN which initiates Subsequent CPAC procedure that the latest SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. Also, the MN may indicate to the (candidate) target SN that the latest SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. For instance, an indication to indicate that the SCG failure occurs in subsequent CPC may be included in the SCG FAILURE INFORMATION REPORT message or the new Xn or X2 message.

c) If more than one RRC (connection) reconfiguration complete messages are received before receiving SCG failure information message from the UE, the MN decides that the received SCG failure information message is for subsequent CPC of the Subsequent CPAC procedure. The MN may indicate to the initial source SN or the SN which initiates Subsequent CPAC procedure that the latest SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. Also, the MN may indicate to the (candidate) target SN that the latest SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure, e.g. via the SCG FAILURE INFORMATION REPORT message or a new Xn or X2 message. For instance, an indication to indicate that the SCG failure occurs in subsequent CPC of the Subsequent CPAC procedure may be included in the SCG FAILURE INFORMATION REPORT message or the new Xn or X2 message.

Based on Option#E or Option#F, the network can perform corresponding MRO analysis or optimization for initial CPAC or subsequent CPC of the Subsequent CPAC procedure, e.g. according to above descriptions in Embodiment 2-2.

Embodiment 3 (MRO for a near-failure successful case)

Currently only the latest successful PSCell addition/change or CPA/CPC can be stored in one SPR. In the present disclosure, a UE may store and report information related with one or more near-failure successful events happened in the Subsequent CPAC or SCG selective activation procedure in one report. The Subsequent CPAC or SCG selective activation procedure may be initiated by a MN or a source SN. For example, one or more near-failure successful events happened in the Subsequent CPAC or SCG selective activation procedure can be stored and reported in one SPR. Or, one or more near-failure successful events happened in the Subsequent CPAC or SCG selective activation procedure can be stored and reported in a new report, e.g. the new report is one report that is introduced for a Subsequent CPAC or SCG selective activation procedure. For instance:

(1) the UE may report the latest near-failure successful CPAC execution in one SPR or the new report; or

(2) the UE may report one near-failure initial successful CPAC execution and at least one near-failure successful subsequent CPC in one SPR or the new report; or

(3) the UE may report one or more near-failure successful subsequent CPC executions in one SPR or the new report.

The number of near-failure successful events happened in the Subsequent CPAC or SCG selective activation procedure that to be stored in one SPR or the new report can be a default value, or can be configured by a network node (e.g. a MN or initial source SN or the SN which initiates Subsequent CPAC procedure) . Or, the UE may store several near-failure successful events until:

(1) initial CPAC execution or subsequent CPC execution fails; or

(2) a SCG failure occurs or MCG failure occurs; or

(3) PCell change occurs or RRC release message is received; or

(4) an indication of stopping Subsequent CPAC or SCG selective activation procedure is received.

The details of successful report for a MN initiated Subsequent CPAC or SCG selective activation procedure can refer to Embodiment 3-1 as below, and the details of successful report for a SN initiated Subsequent CPAC or SCG selective activation procedure can refer to Embodiment 3-2 as below.

Embodiment 3-1 (a successful report for a MN initiated Subsequent CPAC or SCG selective activation procedure)

As legacy, timer T310 or T312 or T304 related threshold can be configured as a trigger condition of a SPR or a new report for near-failure successful Subsequent CPAC or SCG selective activation.

In a MN initiated Subsequent CPAC or SCG selective activation procedure, the issue regarding "which node decides the T310 or T312 related threshold as a trigger condition of the SPR or the new report for near-failure successful Subsequent CPAC or SCG selective activation procedure" needs to be solved. In Embodiment 3-1, there may be following two options:

(1) Option#V: the initial source SN decides or generates T310 or T312 related trigger condition of the SPR or the new report for initial CPC of the Subsequent CPAC procedure. Each (candidate) target SN decides or generates T310 or T312 related trigger condition of the SPR or the new report for one or more subsequent CPCs of the Subsequent CPAC procedure. For example, T310 related trigger condition of the SPR or the new report for anyone of the one or more subsequent CPCs may be common or different. T312 related trigger condition of the SPR or the new report for anyone of the one or more subsequent CPCs may be common or different. If common, the common T310 related trigger condition of the SPR or the new report or the common T312 related trigger condition of the SPR or the new report for one or more subsequent CPCs would be sent to the UE e.g. in Reference SCG configuration included in an RRC reconfiguration message. If different, separate T310 related trigger conditions of the SPR or the new report or separate T310 related trigger conditions of SPR or the new report would be sent to the UE e.g. in each RRC reconfiguration message related to corresponding (candidate) target PSCell.

(2) Option#W: the MN decides or generates T310 or T312 related trigger condition (for example, T310 or T312 related threshold, e.g. a percentage value) of the SPR or the new report for initial CPA of the Subsequent CPAC procedure, or for initial CPC of the Subsequent CPAC procedure, or for one or more subsequent CPCs of the Subsequent CPAC procedure, e.g. autonomously, or based on inputs from the initial source SN and one or more (candidate) target SNs. For example, after getting the configured T310 or T312 timer values from the initial source SN and one or more (candidate) target SNs) , the T310 related trigger condition (s) of the SPR or the new report for initial CPC/CPA and at least one subsequent CPC may be the same or different, or the T312 related trigger condition (s) of the SPR or the new report for initial CPC/CPA and at least one subsequent CPC may be the same or different. If the same, the common T310 related trigger condition of the SPR or the new report or the common T312 related trigger condition of the SPR or the new report would be sent to the UE e.g. in Reference SCG configuration included in an RRC reconfiguration message, and an indication to indicate that the T310 or T312 related trigger condition of the SPR or the new report is for both initial CPC/CPA and at least one subsequent CPC may be sent to the UE. If different, separate T310 related trigger conditions of the SPR or the new report or separate T312 related trigger conditions of the SPR or the new report would be sent to the UE with the associated corresponding (candidate) target PSCell (s) .

In a MN initiated Subsequent CPAC or SCG selective activation procedure, the issue regarding "which node decides the T304 related threshold as trigger condition of the SPR or the new report for near-failure successful Subsequent CPAC or SCG selective activation procedure" needs to be solved. In Embodiment 3-1, a (candidate) target SN decides or generates T304 related trigger condition (s) (for example, T304 related threshold, e.g. a percentage value) of the SPR or the new report for initial CPA of the Subsequent CPAC procedure, or initial CPC of the Subsequent CPAC procedure, and/or at least one subsequent CPC of the Subsequent CPAC procedure. The T304 related trigger condition (s) of the SPR or the new report for initial CPC/CPA and at least one subsequent CPC may be same or different. If same, the common T304 related trigger condition of the SPR or the new report would be sent to the UE e.g. in Reference SCG configuration included in an RRC reconfiguration message. An indication to indicate that the T304 related trigger condition of the SPR or the new report is for both initial CPC/CPA and at least one subsequent CPC may be also sent to the UE. If different, separate T304 related trigger conditions of the SPR or the new report would be sent to the UE e.g. in each RRC Reconfiguration message related to corresponding (candidate) target PSCell. For another example, the T304 related trigger condition (s) of the SPR or the new report for anyone of the at least one subsequent CPC may be the same or different. If the same, the common T304 related trigger condition would be sent to the UE e.g. in Reference SCG configuration included in an RRC reconfiguration message. An indication to indicate that the T304 related trigger condition of the SPR or the new report is for anyone of the at least one subsequent CPC may be also sent to the UE. If different, separate T304 related trigger conditions of the SPR or the new report would be sent to the UE e.g. in each RRC Reconfiguration message related to corresponding (candidate) target PSCell.

In case the SPR or the new report is retrieved in a “new node” (different from the node that sent RRC reconfiguration message to the UE i.e., “old MN” ) , the SPR or the new report is always sent from the “new node” to the “old MN” , and then forwarded to the respective node (s) which should perform optimization for the SPR or the new report (i.e. the node which generates the trigger condition (s) of the SPR or the new report that triggers the SPR or the new report) .

In Embodiment 3-1, in a MN initiated Subsequent CPAC or SCG selective activation procedure, if a SPR or a new report is generated due to T310 or T312 related trigger condition of the SPR or the new report is fulfilled, considering the node which decides or generates T310 or T312 related trigger condition (s) (for example, T310 or T312 related threshold, e.g. a percentage value) of the SPR or the new report for initial CPAC or at least one subsequent CPC of the Subsequent CPAC procedure is different (e.g. as above Option#V shows, the initial source SN decides or generates T310 or T312 related trigger condition of the SPR or the new report for initial CPC of the Subsequent CPAC procedure, each (candidate) target SN decides or generates T310 or T312 related trigger condition of the SPR or the new report for at least one subsequent CPC of the Subsequent CPAC procedure. It means that if the SPR or the new report is generated for the initial CPC of the Subsequent CPAC procedure due to T310 or T312 related trigger condition of the SPR or the new report is fulfilled, the old MN would forward the SPR or the new report to the initial source SN. If the SPR or the new report is generated for the subsequent CPC of the Subsequent CPAC procedure due to T310 or T312 related trigger condition of the SPR or the new report is fulfilled, the old MN would forward the SPR or the new report to the corresponding target SN) , to enable correct SPR or new report forwarding at the network side, the MN needs to identify whether the SPR or the new report is generated for near-failure successful initial CPAC or near-failure successful subsequent CPC:

(1) Option#H: (UE-based solution) the UE indicates network about whether the SPR or the new report is generated for initial CPAC or subsequent CPC of the Subsequent CPAC procedure, e.g. the UE includes an indication to indicate the SPR or the new report is for initial CPA or for initial CPC or for subsequent CPC in the SPR or the new report, for example, extend cause value of the SPR or the new report to introduce e.g. t310 cause for initial CPA/CPC, t312 cause for initial CPA/CPC, t310 cause for subsequent CPC, t312 cause subsequent CPC; or, include an explicit indication concerning SPR or new report is for initial CPA or for initial CPC or for subsequent CPC in the SPR or the new report. Also, the UE prioritizes to report the measurement results of one or more candidate target PSCells that evaluated for subsequent CPC of the Subsequent CPAC procedure in the SPR or the new report. If the SPR or the new report is for initial CPC of the Subsequent CPAC procedure, the MN forwards the SPR or the new report to the initial source SN for MRO optimisation, optionally, the MN forwards an indication which indicates that the SPR or the new report is for initial CPC of the Subsequent CPAC procedure explicitly to the initial source SN for MRO optimisation; if the SPR or the new report is for subsequent CPC of the Subsequent CPAC procedure, the MN forwards the SPR or the new report to the corresponding target SN which manages the target PSCell indicated in the SPR or the new report for MRO optimisation, optionally, the MN forwards an indication which indicates that the SPR or the new report is for subsequent CPC of the Subsequent CPAC procedure explicitly to the corresponding target SN for MRO optimisation.

(2) Option#I: (network-based solution)

a) If only one RRC (connection) reconfiguration complete message is received before receiving the SPR or the new report, the MN knows that the received SPR or new report is for initial CPA or initial CPC of the Subsequent CPAC procedure, then, the MN forwards the SPR or the new report to the initial source SN for MRO optimisation. Optionally, the MN forwards an indication which indicates that the SPR or the new report is for initial CPA or initial CPC of the Subsequent CPAC procedure explicitly to the initial source SN for MRO optimisation.

b) If two RRC (connection) reconfiguration complete messages are received before receiving the SPR or the new report, the MN decides whether the SPR or the new report is for initial CPA or initial CPC or subsequent CPC of the Subsequent CPAC procedure based on whether SCG failure information message is received, for example, if before a SCG failure happens, the UE connects with the MN and the initial source SN, if the SCG failure information message is received, the MN decides that the received SPR or the new report is for initial CPC of the Subsequent CPAC procedure (e.g. for the case that SPR or new report for initial CPC is generated but the SPR or the new report is not sent to network immediately, an RLF occurs shortly after a successful subsequent CPC execution, before receiving the SPR or the new report, the MN receives two RRC (connection) reconfiguration complete messages) , and then, the MN forwards the SPR or the new report to the initial source SN for MRO optimisation, optionally, the MN forwards an indication which indicates that the SPR or the new report is for initial CPC of the Subsequent CPAC procedure explicitly to the initial source SN for MRO optimisation; otherwise, the MN decides that the received SPR or new report is for subsequent CPC of the Subsequent CPAC procedure, then, the MN forwards the SPR or the new report to the corresponding target SN which manages the target PSCell included in the SPR or the new report for MRO optimisation, optionally, the MN forwards an indication which indicates that the SPR or the new report is for subsequent CPC of the Subsequent CPAC procedure explicitly to the corresponding target SN for MRO optimisation. For another example, if the UE only connects with the MN before a SCG failure happens, and if the SCG failure information message is received, the MN decides that the received SPR or the new report is for initial CPA of the Subsequent CPAC procedure (e.g. for the case that SPR or new report for initial CPA is generated but the SPR or new report is not sent to the network immediately, an RLF occurs shortly after a successful subsequent CPC execution, before receiving the SPR or the new report, the MN receives two RRC (connection) reconfiguration complete messages) , then, the MN performs MRO optimisation; otherwise, the MN decides that the received SPR or new report is for subsequent CPC of the Subsequent CPAC procedure, then, the MN forwards the SPR or the new report to the corresponding target SN which manages the target PSCell included in the SPR or the new report for MRO optimisation, optionally, the MN forwards an indication which indicates that the SPR or the new report is for subsequent CPC of the Subsequent CPAC procedure explicitly to the corresponding target SN for MRO optimisation.

c) If more than two RRC (connection) reconfiguration complete messages are received before receiving the SPR or the new report, the MN decides that the received SPR or new report is for subsequent CPC of the Subsequent CPAC procedure, and then, the MN forwards the SPR or new report to the corresponding target SN which manages the target PSCell included in the SPR for MRO optimisation, optionally, the MN forwards n indication which indicates that the SPR or the new report is for subsequent CPC of the Subsequent CPAC procedure explicitly to the corresponding target SN for MRO optimisation.

In a MN initiated Subsequent CPAC or SCG selective activation procedure, if a MN decides or generates T310 or T312 related trigger condition of a SPR or a new report for initial CPA of the Subsequent CPAC procedure, or for initial CPC of the Subsequent CPAC procedure, or for at least one subsequent CPC of the Subsequent CPAC procedure, (as above Option#W shows) and SPR or the new report is generated due to T310 or T312 related trigger condition is fulfilled, the MN performs MRO analysis and optimisation based on the received SPR or new report.

In a MN initiated Subsequent CPAC or SCG selective activation procedure, if a SPR or a new report is generated due to T304 related trigger condition of the SPR or the new report is fulfilled, since a (candidate) target SN decides or generates T304 related trigger condition (s) of the SPR or the new report for initial CPA/CPC and/or at least one subsequent CPC, no matter whether the SRR or new report is for initial CPA or for initial CPC or for subsequent CPC, the MN forwards the SPR or the new report to the corresponding target SN which manages the target PSCell included in the SPR or the new report for MRO optimisation.

Embodiment 3-2 (asuccessful report for SN initiated Subsequent CPAC or SCG selective activation procedure)

As legacy, T310 or T312 or T304 related threshold can be configured as trigger condition of a SPR or a new report for near-failure successful Subsequent CPAC or SCG selective activation.

In SN initiated Subsequent CPAC or SCG selective activation procedure, for the issue on which node decides the T310 or T312 related threshold as trigger condition of the SPR or the new report for near-failure successful Subsequent CPAC or SCG selective activation procedure, the initial source SN decides or generates T310 or T312 related trigger condition of the SPR or the new report for initial CPC of the Subsequent CPAC procedure, each (candidate) target SN decides or generates T310 or T312 related trigger condition of the SPR or the new report for at least one subsequent CPC of the Subsequent CPAC procedure (e.g. T310 related trigger condition of the SPR or the new reports for anyone of the at least one subsequent CPC may be common or different, or T312 related trigger condition of the SPR or the new report for anyone of the at least one subsequent CPC may be common or different. If common, the common T310 related trigger condition for the at least one subsequent CPC would be sent to the UE e.g. in Reference SCG configuration included in an RRC reconfiguration message, or, the common T312 related trigger condition for the at least one subsequent CPC would be sent to the UE e.g. in Reference SCG configuration included in an RRC reconfiguration message. If different, separate T310 related trigger conditions of the SPR or the new report would be sent to the UE e.g. in each RRC reconfiguration message related to corresponding (candidate) target PSCell, or, separate T312 related trigger conditions of the SPR or the new report would be sent to the UE e.g. in each RRC reconfiguration message related to corresponding (candidate) target PSCell) .

In a SN initiated Subsequent CPAC or SCG selective activation procedure, for the issue regarding which node decides the T304 related threshold as trigger condition of a SPR or a new report for near-failure successful Subsequent CPAC or SCG selective activation procedure, (candidate) target SN decides or generates T304 related trigger condition (s) of the SPR or the new report for initial CPA of the Subsequent CPAC procedure, or initial CPC of the Subsequent CPAC procedure, and/or at least one subsequent CPC of the Subsequent CPAC procedure. T304 related trigger condition (s) of the SPR or the new report for initial CPA/CPC and at least one subsequent CPC may be same or different. If same, the common T304 related trigger condition of the SPR or the new report would be sent to the UE e.g. in Reference SCG configuration included in an RRC reconfiguration message. An indication to indicate that the T304 related trigger condition of the SPR or the new report is for both initial CPA/CPC and at least one subsequent CPC may be also sent to the UE. If different, separate T304 related trigger conditions of the SPR or the new report would be sent to the UE e.g. in each RRC Reconfiguration message related to corresponding (candidate) target PSCell. For another example, the T304 related trigger condition (s) of the SPR or the new report for anyone of the at least one subsequent CPC may be same or different. If same, the common T304 related trigger condition would be sent to the UE e.g. in Reference SCG configuration included in an RRC reconfiguration message. An indication to indicate that the T304 related trigger condition of the SPR or the new report is for anyone of the at least one subsequent CPC may be also sent to the UE. If different, separate T304 related trigger conditions of the SPR or the new report would be sent to the UE e.g. in each RRC Reconfiguration message related to corresponding (candidate) target PSCell.

In case that the SPR or the new report is retrieved in a “new node” (different from the node that sent RRC reconfiguration message to the UE i.e., “old MN” ) , the SPR or the new report is always sent from the “new node” to the “old MN” , and then is forwarded to the respective node (s) which should perform optimization for the SPR or the new report (i.e. the node which generates the trigger condition (s) of the SPR or the new report that triggers the SPR or the new report) .

In a SN initiated Subsequent CPAC or SCG selective activation procedure, if a SPR or a new report is generated due to T310 or T312 related trigger condition of the SPR or the new report is fulfilled, considering the node which decides or generates T310 or T312 related trigger condition (s) of the SPR or the new report for initial CPC or at least one subsequent CPC of the Subsequent CPAC procedure is different (i.e. the initial source SN decides or generates T310 or T312 related trigger condition of the SPR or the new report for initial CPC of the Subsequent CPAC procedure, each (candidate) target SN decides or generates T310 or T312 related trigger condition of the SPR or the new report for subsequent CPC of the Subsequent CPAC procedure. It means that if the SPR or the new report is generated for the initial CPC of the Subsequent CPAC procedure due to T310 or T312 related trigger condition of the SPR or the new report is fulfilled, the old MN would forward the SPR or the new report to the initial source SN. If the SPR or the new report is generated for the subsequent CPC of the Subsequent CPAC procedure due to T310 or T312 related trigger condition of the SPR or the new report is fulfilled, the old MN would forward the SPR or the new report to the corresponding target SN) , to enable correct SPR or new report forwarding at the network side, the MN needs to identify whether the SPR or the new report is generated for near-failure successful initial CPC or near-failure successful subsequent CPC of the Subsequent CPAC procedure, there may be following two options:

(1) Option#J: (UE-based solution) a UE indicates network about whether the SPR or the new report is generated for initial CPC or subsequent CPC of the Subsequent CPAC procedure. For example, the UE includes an indication to indicate the SPR or the new report is for initial CPC or for subsequent CPC in the SPR or the new report, for example, extend cause value of the SPR or the new report to introduce e.g. t310 cause for initial CPC, t312 cause for initial CPC, t310 cause for subsequent CPC, t312 cause subsequent CPC. Or, the UE includes an explicit indication concerning the SPR or the new report is for initial CPC or for subsequent CPC in the SPR or the new report. Also, the UE prioritizes to report the measurement results of one or more candidate target PSCells that evaluated for subsequent CPC of the Subsequent CPAC procedure in the SPR or the new report. If the SPR or the new report is for initial CPC of the Subsequent CPAC procedure, the MN forwards the SPR or the new report to the initial source SN for MRO optimisation, optionally, the MN forwards an indication which indicates that the SPR or the new report is for initial CPC of the Subsequent CPAC procedure explicitly to the initial source SN for MRO optimisation. If the SPR or the new report is for subsequent CPC of the Subsequent CPAC procedure, the MN forwards the SPR or the new report to the corresponding target SN which manages the target PSCell indicated in the SPR or the new report for MRO optimisation, optionally, the MN forwards the indication which indicates the SPR or the new report is for subsequent CPC of the Subsequent CPAC procedure explicitly to the corresponding target SN for MRO optimisation.

(2) Option#K: (network-based solution)

a) If only one RRC (connection) reconfiguration complete message is received before receiving the SPR or the new report, the MN knows that the received SPR or new report is for initial CPC of the Subsequent CPAC procedure. Then, the MN forwards the SPR or the new report to the initial source SN for MRO optimisation. Optionally, the MN forwards an indication which indicates that the SPR or the new report is for initial CPC of the Subsequent CPAC procedure explicitly to the initial source SN for MRO optimisation.

b) If two RRC (connection) reconfiguration complete messages are received before receiving SPR or the new report, the MN decides whether the SPR or the new report is for initial CPC or subsequent CPC of the Subsequent CPAC procedure based on whether SCG failure information message is received. For example, if the SCG failure information message is received, the MN decides that the received SPR or the new report is for initial CPC of the Subsequent CPAC procedure (e.g. for the case that SPR or the new report for initial CPC is generated but the SPR or the new report is not sent to network immediately, an RLF occurs shortly after a successful subsequent CPC execution, before receiving SPR or the new report, the MN receives two RRC (connection) reconfiguration complete messages) . Then, the MN forwards the SPR or the new report to the initial source SN for MRO optimisation, optionally, the MN forwards an indication which indicates that the SPR or the new report is for initial CPC of the Subsequent CPAC procedure explicitly to the initial source SN for MRO optimisation. Otherwise, the MN decides that the received SPR or new report is for subsequent CPC, and then, the MN forwards the SPR or the new report to the corresponding target SN which manages the target PSCell included in the SPR or the new report for MRO optimisation, optionally, the MN forwards the indication which indicates the SPR or the new report is for subsequent CPC of the Subsequent CPAC procedure explicitly to the corresponding target SN for MRO optimisation.

c) If more than two RRC (connection) reconfiguration complete messages are received before receiving the SPR or the new report, the MN decides that the received SPR or new report is for subsequent CPC of the Subsequent CPAC procedure. Then, the MN forwards the SPR or the new report to the corresponding target SN which manages the target PSCell included in the SPR for MRO optimisation, optionally, the MN forwards an indication which indicates that the SPR or the new report is for subsequent CPC of the Subsequent CPAC procedure explicitly to the corresponding target SN for MRO optimisation.

In a SN initiated Subsequent CPAC or SCG selective activation procedure, if a SPR or a new report is generated due to T304 related trigger condition of the SPR or the new report is fulfilled, since (candidate) target SN decides or generates T304 related trigger condition (s) of the SPR or the new report for initial CPA/CPC and/or at least one subsequent CPC, no matter whether SRR or new report is for initial CPC or for subsequent CPC, the MN may forward the SPR or new report to the corresponding target SN which manages the target PSCell included in the SPR or the new report for MRO optimisation.

The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A first network node, comprising:

at least one memory; and

at least one processor coupled to the at least one memory and configured to cause the first network node to:

in case that a secondary cell group (SCG) failure occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure, determine the SCG failure occurs in which one of the following:

an initial conditional PSCell addition (CPA) of the subsequent CPAC procedure;

an initial conditional PSCell change (CPC) of the subsequent CPAC procedure; and

a subsequent CPC of the subsequent CPAC procedure,

wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.
The first network node of Claim 1, wherein the at least one processor is configured to cause the first network node to:

if a selected PSCell is not included in a first set of candidate target PSCells provided by the first network node, determine that wrong candidate target PSCell selection occurs at the first network node;

if the selected PSCell is included in the first set of candidate target PSCells, but not included in a second set of candidate target PSCells selected by a second network node:

transmit, to the second network node, information indicating that wrong candidate target PSCell selection occurs at the second network node;

transmit SCG failure related information to the second network node; or

transmit cell information of the selected PSCell to the second network node; and

if the selected PSCell is included in the second set of candidate target PSCells:

if the SCG failure occurs in the initial CPA, determine that one or more wrong CPA execution conditions are set for the initial CPA;

if the SCG failure occurs in the initial CPC, determine that one or more wrong CPC execution conditions are set for the initial CPC; and

if the SCG failure occurs in the subsequent CPC:

transmit, to the second network node, information indicating that one or more wrong CPC execution conditions are set for the subsequent CPC;

transmit the SCG failure related information to the second network node; or

transmit the cell information of the selected PSCell to the second network node.
The first network node of Claim 1, wherein the at least one processor is configured to cause the first network node to receive, from the UE or a third network node, information indicating that the SCG failure occurs in the initial CPA, information indicating that the SCG failure occurs in the initial CPC, or information indicating that the SCG failure occurs in the subsequent CPC.
The first network node of Claim 1, wherein the first network node is a master node (MN) , and to determine the SCG failure occurs in which one of the initial CPA, the initial CPC, and the subsequent CPC, the at least one processor is configured to cause the MN to:

if none radio resource control (RRC) reconfiguration complete message is received before receiving SCG failure related information, determine that the SCG failure occurs in the initial CPA or the initial CPC;

if one RRC reconfiguration complete message is received before receiving the SCG failure related information, determine time duration between receiving the one RRC reconfiguration complete message and the SCG failure related information; and

if more than one RRC reconfiguration complete messages are received before receiving the SCG failure related information, determine that the SCG failure occurs in the subsequent CPC.
The first network node of Claim 4, wherein the at least one processor is further configured to cause the MN to transmit, to a secondary node (SN) managing a source PSCell in the initial CPA or the initial CPC, information indicating that the SCG failure occurs in the initial CPA, information indicating that the SCG failure occurs in the initial CPC, or information indicating that the SCG failure occurs in the subsequent CPC.
The first network node of Claim 1, wherein the at least one processor is configured to cause the first network node to determine that the SCG failure occurs during the subsequent CPAC procedure in response to detecting an event, wherein the event is one of the following:

the UE performs a CPC execution from a first PSCell to a second PSCell successfully, but within a predefined limited time the UE performs a CPC execution from the second PSCell to a third PSCell successfully;

the UE performs the CPC execution from the first PSCell to the second PSCell, but the CPC execution is not successful or the SCG failure occurs shortly after the CPC execution is successful, wherein the first PSCell is a suitable PSCell based on measurements reported from the UE; and

the UE receives configuration information for the subsequent CPAC procedure, while the SCG failure occurs before one or more execution conditions of the initial CPC or the subsequent CPC are fulfilled.
The first network node of Claim 1, wherein the first network node is a master node (MN) , and the at least one processor is configured to cause the MN to:

generate a first set of trigger conditions related to a successful report, wherein the first set of trigger conditions is for at least one of the initial CPA or one or more subsequent CPCs of the subsequent CPAC procedure, or for at least one of the initial CPC or the one or more subsequent CPCs; and

transmit the first set of trigger conditions to the UE.
The first network node of Claim 1, wherein the first network node is a master node (MN) , and the at least one processor is configured to cause the MN to:

receive at least one of the following from a candidate target secondary node (SN) :

a third set of trigger conditions related to a successful report, wherein the third set of trigger conditions is for at least one of the initial CPA or one or more subsequent CPCs of the subsequent CPAC procedure, or for at least one of the initial CPC or the one or more subsequent CPCs; or

a fourth set of trigger conditions related to the successful report for the one or more subsequent CPCs; and

transmit at least one of the third set of trigger conditions and the fourth set of trigger conditions to the UE.
The first network node of Claim 1, wherein the first network node is a MN, and the at least one processor is configured to cause the MN to:

receive a successful report from the UE; and

determine the successful report is for which one of the initial CPA, the initial CPC, and the subsequent CPC.
The first network node of Claim 9, wherein the first network node is the MN, and the at least one processor is configured to cause the MN to receive, from the UE, information indicating that the successful report is for the initial CPA, information indicating that the successful report is for the initial CPC, or information indicating that the successful report is for the subsequent CPC.
The first network node of Claim 9, wherein the first network node is the MN, and to determine the successful report is for which one of the initial CPA, the initial CPC, and the subsequent CPC, the at least one processor is configured to cause the MN to:

if only one radio resource control (RRC) reconfiguration complete message is received before receiving the successful report, determine that the successful report is for the initial CPA or the initial CPC;

if two RRC reconfiguration complete messages are received before receiving the successful report, determine whether a SCG failure information message is received; and

if more than two RRC reconfiguration complete messages are received before receiving the successful report, determine that the successful report is for the subsequent CPC.
A candidate target secondary node (SN) , comprising:

at least one memory; and

at least one processor coupled to the at least one memory and configured to cause the candidate target SN to:

determine which one of the following occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure:

wrong candidate target PSCell selection at the candidate target SN; and

one or more wrong CPC execution conditions set at the candidate target SN,

wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.
The candidate target SN of Claim 12, wherein the at least one processor is configured to cause the candidate target SN to receive an indication from a network node, and wherein the indication indicates one of the following:

at least one wrong candidate target PSCell is selected at the candidate target SN;

at least one wrong CPC execution condition is set at the candidate target SN;

secondary cell group (SCG) failure related information; and

cell information of a PSCell selected during the subsequent CPAC procedure.
The candidate target SN of Claim 12, wherein the subsequent CPAC procedure includes:

an initial conditional PSCell addition (CPA) ; an initial conditional PSCell change (CPC) ;

and one or more subsequent CPCs, and wherein the at least one processor is configured to cause the candidate target SN to:

generate a fourth set of trigger conditions related to a successful report for the one or more subsequent CPCs, wherein the fourth set of trigger conditions is associated with timer T310 or timer T312; and

transmit the fourth set of trigger conditions to a master node (MN) .
The candidate target SN of Claim 12, wherein the subsequent CPAC procedure includes:

an initial conditional PSCell addition (CPA) ; an initial conditional PSCell change (CPC) ;

and one or more subsequent CPCs, and wherein the at least one processor is configured to cause the candidate target SN to:

generate a third set of trigger conditions related to a successful report, wherein the third set of trigger conditions is for at least one of the initial CPA or one or more subsequent CPCs of the subsequent CPAC procedure, or for at least one of the initial CPC or the one or more subsequent CPCs; and

transmit the third set of trigger conditions to a master node (MN) , wherein the third set of trigger conditions is associated with timer T304.
A user equipment (UE) , comprising:

at least one memory; and

at least one processor coupled to the at least one memory and configured to cause the UE to:

in case that a secondary cell group (SCG) failure occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure, transmit information indicating the SCG failure occurs in which one of:

an initial conditional PSCell addition (CPA) of the subsequent CPAC procedure;

an initial conditional PSCell change (CPC) of the subsequent CPAC procedure; and

a subsequent CPC of the subsequent CPAC procedure,

wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.
The UE of Claim 16, wherein the at least one processor is configured to cause the UE to determine that the SCG failure occurs during the subsequent CPAC procedure in response to detecting an event, wherein the event is one of the following:

the UE performs a CPC execution from a first PSCell to a second PSCell successfully, but within a predefined limited time the UE performs a CPC execution from the second PSCell to a third PSCell successfully;

the UE performs the CPC execution from the first PSCell to the second PSCell, but the CPC execution is not successful or the SCG failure occurs shortly after the CPC execution is successful, wherein the first PSCell is a suitable PSCell based on measurements reported from the UE; and

the UE receives configuration information for the subsequent CPAC procedure, while the SCG failure occurs before one or more executions condition of the initial CPC or the subsequent CPC are fulfilled.
The UE of Claim 16, wherein the at least one processor is configured to cause the UE to perform one of:

receiving a set of trigger conditions related to a successful report, wherein the set of trigger conditions includes at least one of the following:

a first set of trigger conditions, wherein the first set of trigger conditions is for at least one of the initial CPA or one or more subsequent CPCs of the subsequent CPAC procedure, or for at least one of the initial CPC or the one or more subsequent CPCs;

a second set of trigger conditions for the initial CPC; or

a fourth set of trigger conditions for the one or more subsequent CPCs; or

generating a successful report.
The UE of Claim 18, wherein the at least one processor is configured to cause the UE to transmit, to the MN, information indicating that the successful report is for the initial CPA, information indicating that the successful report is for the initial CPC, or information indicating that the successful report is for the subsequent CPC.
A processor for wireless communication, comprising:

at least one controller coupled with at least one memory and configured to cause the processor to:

in case that a secondary cell group (SCG) failure occurs during a subsequent conditional primary secondary cell group cell (PSCell) addition or change (CPAC) procedure, determine the SCG failure occurs in which one of the following:

an initial conditional PSCell addition (CPA) of the subsequent CPAC procedure;

an initial conditional PSCell change (CPC) of the subsequent CPAC procedure; and

a subsequent CPC of the subsequent CPAC procedure,

wherein during the subsequent CPAC procedure, a user equipment (UE) doesn’t release configuration information for the subsequent CPAC procedure after a successful completion of the initial CPA or the initial CPC or the subsequent CPC or a CPAC execution.