Method and apparatus for MRO mechanism for mobility program

Abstract

Embodiments of the present application relate to methods and apparatus for a mobility robustness optimization (MRO) mechanism for a mobility procedure, such as an MRO mechanism for a conditional handover (CHO) procedure, or an MRO mechanism for a conditional primary-secondary cell group cell (PSCell) change / conditional PSCell addition (CPC / CPA) procedure, or an MRO mechanism for a CHO including a target primary cell group (MCG) and a candidate secondary cell group (SCG) for the CPC / CPA procedure. In accordance with an embodiment of the present application, a network node includes a transceiver and a processor coupled to the transceiver, and the processor is configured to cause the network node to transmit a signal to the transceiver when a failure occurs in one of the following. Obtaining information for recovering the failed cell: a CHO procedure, a conditional PSCell addition or change (CPAC) procedure, and a CHO including a target MCG and a candidate SCG for a CPC / CPA procedure; and performing an analysis on the failure.

Description

Technical Field

[0001] Embodiments of the present application generally relate to a mobility robustness optimization (MRO) mechanism for mobility procedures, for example, an MRO mechanism for a conditional handover (CHO) procedure, or an MRO mechanism for a conditional primary secondary cell group cell (PSCell) change / conditional PSCell addition (CPC / CPA) procedure, or a method and apparatus for an MRO mechanism for a CHO including a target primary cell group (MCG) and a candidate secondary cell group (SCG) for a CPC / CPA procedure. Background Art

[0002] In a multi-radio dual connectivity (MR-DC) scenario, a UE with multiple transceivers can be configured to utilize resources provided by two different nodes connected via a non-ideal backhaul. One of the nodes can provide New Radio (NR) access, and the other node can provide Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA) (E-UTRA) or NR access. One node can serve as a master node (MN) and the other node can serve as a secondary node (SN). The MN and SN are connected via a network interface (e.g., an Xn or X2 interface as specified in the 3rd Generation Partnership Project (3GPP) standard documents), and at least the MN is connected to the core network.

[0003] Currently, the conditional PSCell addition (CPA) procedure and the conditional PSCell change (CPC) procedure are supported. The CPAC procedure can be a CPA procedure or a CPC procedure. According to the agreement of the 3GPP standard document, the CPAC procedure is defined as a PSCell addition or PSCell change performed by the UE when the configured CPAC execution condition is reached or satisfied. The UE starts to evaluate the CPAC execution condition when it receives the CPAC-related configuration information, and stops evaluating the CPAC execution condition once the PSCell addition and / or change procedure is triggered or executed. Triggering or executing the PSCell addition and / or change procedure means that when the CPAC execution condition of the candidate PSCell is met or satisfied ("candidate PSCell" may also be named "CPAC candidate PSCell"), the UE determines the candidate PSCell as the target PSCell and performs the PSCell addition or change procedure with the target PSCell, for example, the UE performs the RA procedure towards the target PSCell.

[0004] CHO is defined as a handover performed by a user equipment (UE) when one or more CHO execution conditions are met. The UE starts evaluating the one or more CHO execution conditions upon receiving CHO-related configuration information (e.g., including one or more configurations associated with a candidate PCell and one or more CHO execution conditions), and stops evaluating the CHO execution conditions during CHO execution or once the one or more CHO execution conditions are met. CHO execution means that when the CHO execution conditions of a candidate PCell are met or satisfied ("candidate PCell" may also be named "CHO ​​candidate PCell"), the UE determines the candidate PCell as the target PCell and performs a PCell change or handover procedure with the target PCell, for example, the UE performs a RA procedure towards the target PCell.

[0005] In a CHO including a target MCG and candidate SCG for a CPC / CPA procedure, when the UE receives a configuration for a CHO including a target MCG and candidate SCG for a CPC / CPA procedure (i.e., a CHO configuration involving or including a CPC or CPA configuration, or a configuration for a CHO with a candidate SCG procedure), for example, when the UE receives a configuration for a CHO candidate (target) PCell, a CHO execution condition, a configuration for a CPAC candidate (target) PSCell, and a CPAC execution condition, CHO evaluation and CPC or CPA evaluation may be concurrent. For example, the UE starts evaluating the CHO execution condition of the candidate (target) PCell and the CPAC execution condition of the candidate (target) PSCell (when receiving the configuration for the CHO with a candidate SCG procedure) at the same time. The UE does not perform CPC or CPA unless the CHO execution condition of the CHO candidate PCell is met.

[0006] At present, the details of the MRO mechanism for the CHO that includes the target MCG and candidate SCG for the CPC / CPA program (which may also be named as the CHO that includes the target MCG and candidate SCG for the CPA / CPC program, or the CHO with the candidate SCG program, or the CHO that includes the target MCG and candidate SCG program, or the CHO that includes the candidate target MCG and candidate target SCG for the CPC / CPA program, or the CHO that includes the candidate target MCG and candidate target SCG program, or the like) have not been discussed. Summary of the Invention

[0007] Some embodiments of the present application provide a network node. The network node includes a transceiver and a processor coupled to the transceiver, wherein the processor is configured to cause the network node to: when a failure occurs in one of the following: a conditional handover (CHO) procedure, a conditional primary and secondary cell group cell (PSCell) add or change (CPAC) procedure, and a CHO including a target primary cell group (MCG) and a candidate secondary cell group (SCG) for a conditional PSCell change / conditional PSCell add (CPC / CPA) procedure, obtain information for recovering the failed cell; and perform analysis on the failure.

[0008] In some embodiments, the network node is a source master node (MN), and the processor is configured to cause the source MN to perform at least one of the following: modify the CPAC candidate PSCell list; transmit first information to at least one candidate SN to indicate that one or more CPAC candidate PSCells are incorrectly selected; instruct one or more candidate MNs to transmit the first information to the at least one candidate SN; optimize a set of CPAC execution conditions; or transmit second information to the one or more candidate MNs to indicate that the set of CPAC execution conditions is improperly configured.

[0009] In some embodiments, the network node is a source master node (MN), the cell is a PSCell, and if the PSCell is not included in the CPAC candidate PSCell list suggested by the source MN, the processor is configured to cause the source MN to modify the CPAC candidate PSCell list.

[0010] In some embodiments, the network node is a source master node (MN), the cell is a PSCell, and if the PSCell is included in a first CPAC candidate PSCell list suggested by the source MN but is not included in a second CPAC candidate PSCell list selected by a candidate SN, then the processor is configured to cause the source MN to: transmit first information to the candidate SN to indicate that the second CPAC candidate PSCell list selected by the candidate SN is inappropriate; or instruct one or more candidate MNs to transmit the first information to the candidate SN.

[0011] In some embodiments, the network node is a source master node (MN), the cell is a PSCell, and if the PSCell is included in a CPAC candidate PSCell list selected by a candidate SN, the processor is configured to cause the source MN to: optimize a set of CPAC execution conditions for the CPAC candidate PSCell list; or transmit a second information to one or more candidate MNs to indicate that the set of CPAC execution conditions is improperly configured.

[0012] In some embodiments, the network node is a source master node (MN), and the processor is configured to cause the source MN to perform at least one of the following: modifying the CHO candidate PCell list; transmitting third information to at least one candidate MN to indicate that the one or more CHO candidate PCells are incorrectly selected; or optimizing a set of CHO execution conditions.

[0013] In some embodiments, the network node is a source master node (MN), the cell is a primary cell (PCell), and if the PCell is not included in a CHO candidate PCell list suggested by the source MN, the processor is configured to cause the source MN to modify the CHO candidate PCell list.

[0014] In some embodiments, the network node is a source master node (MN), the cell is a primary cell (PCell), and if the PCell is included in a first CHO candidate PCell list suggested by the source MN but is not included in a second CHO candidate PCell list selected by a candidate MN, then the processor is configured to cause the source MN to transmit third information to the candidate MN to indicate that the second CHO candidate PCell list selected by the candidate MN is inappropriate.

[0015] In some embodiments, the network node is a source master node (MN), the cell is a primary cell (PCell), and if the PCell is included in a CHO candidate PCell list selected by a candidate MN, the processor is configured to cause the source MN to optimize a set of CHO execution conditions for the CHO candidate PCell list.

[0016] In some embodiments, the processor is configured to cause the source MN to: determine the information of the cell; transmit the information of the cell; or receive the information of the cell.

[0017] In some embodiments, the processor is configured to cause the source MN to: transmit failure-related information associated with the failure; or receive the failure-related information.

[0018] In some embodiments, the network node is a candidate master node (MN), and the processor is configured to cause the candidate MN to perform at least one of the following: modify the CPAC candidate PSCell list; transmit fourth information to at least one candidate SN to indicate that one or more CPAC candidate PSCells are incorrectly selected; optimize a set of CPAC execution conditions; or transmit fifth information to the source MN to indicate that the set of CPAC execution conditions is improperly configured.

[0019] In some embodiments, the network node is a candidate master node (MN), the cell is a PSCell, and if the PSCell is not included in the CPAC candidate PSCell list suggested by the candidate MN, the processor is configured to cause the candidate MN to modify the CPAC candidate PSCell list.

[0020] In some embodiments, the network node is a candidate master node (MN), the cell is a PSCell, and if the PSCell is included in a first CPAC candidate PSCell list proposed by the candidate MN but is not included in a second CPAC candidate PSCell list selected by a candidate SN, then the processor is configured to cause the candidate MN to transmit fourth information to the candidate SN to indicate that the second CPAC candidate PSCell list selected by the candidate SN is inappropriate.

[0021] In some embodiments, the network node is a candidate master node (MN), the cell is a PSCell, and if the PSCell is included in the CPAC candidate PSCell list selected by the candidate SN, then the processor is configured to cause the candidate MN to: optimize a set of CPAC execution conditions for the CPAC candidate PSCell list; or transmit fifth information to the source MN to indicate that the set of CPAC execution conditions is improperly configured.

[0022] In some embodiments, the network node is a candidate master node (MN), and the processor is configured to cause the candidate MN to perform at least one of the following: receive sixth information from the source MN indicating that at least one CHO candidate PCell is incorrectly selected; or modify one or more CHO candidate PCells selected by the candidate MN.

[0023] In some embodiments, the processor is configured to cause the candidate MN to: determine the information of the cell; transmit the information of the cell; or receive the information of the cell.

[0024] In some embodiments, the processor is configured to cause the candidate MN to receive failure-related information associated with the failure.

[0025] In some embodiments, the network node is a source slave node (SN), and the processor is configured to cause the source SN to perform at least one of the following: modify the CPAC candidate PSCell list; transmit seventh information to at least one candidate SN to indicate that one or more CPAC candidate PSCells are incorrectly selected; instruct the source MN to transmit the seventh information to the at least one candidate SN; or optimize a set of CPAC execution conditions.

[0026] In some embodiments, the network node is a source secondary node (SN), the cell is a PSCell, and if the PSCell is not included in the CPAC candidate PSCell list suggested by the source SN, the processor is configured to cause the source SN to modify the CPAC candidate PSCell list.

[0027] In some embodiments, the network node is a source secondary node (SN), the cell is a PSCell, and if the PSCell is included in a first CPAC candidate PSCell list proposed by the source SN but is not included in a second CPAC candidate PSCell list selected by the candidate SN, then the processor is configured to cause the source SN to: transmit seventh information to the candidate SN to indicate that the second CPAC candidate PSCell list selected by the candidate SN is inappropriate; or instruct the source MN to transmit the seventh information to the candidate SN.

[0028] In some embodiments, the network node is a source secondary node (SN), the cell is a PSCell, and if the PSCell is included in a CPAC candidate PSCell list selected by a candidate SN, then the processor is configured to cause the source SN to optimize a set of CPAC execution conditions for the CPAC candidate PSCell list.

[0029] In some embodiments, the processor is configured to cause the source SN to: determine the information of the cell; transmit the information of the cell; or receive the information of the cell.

[0030] In some embodiments, the processor is configured to cause the source SN to receive failure-related information associated with the failure.

[0031] In some embodiments, the failure-related information includes at least one of the following: a first type of execution condition that is met; a second type of execution condition that is met; information indicating whether the CPAC execution condition of the CPAC candidate PSCell is met; information indicating whether the CHO execution condition of the CHO candidate PCell is met; information indicating whether the candidate PSCell that meets the CPAC execution condition is associated with the candidate PCell that meets the CHO execution condition; information indicating whether the leaving condition of the candidate PCell that meets the CHO execution condition is met, for example, when the CPAC execution condition of the CPAC candidate PSCell is met; information indicating whether the leaving condition of the candidate PSCell that meets the CPAC execution condition is met, for example, when the CHO execution condition of the CHO candidate PCell is met; the time elapsed from the time the CHO execution condition is met until the CPAC execution condition is met; or the time elapsed from the time the CPAC execution condition is met until the CHO execution condition is met.

[0032] In some embodiments, the failure is one of: SCG failure, MCG failure, radio link failure (RLF), CHO execution failure, and CPAC execution failure.

[0033] In some embodiments, the failure occurs when configuration information related to the CHO including the target MCG and candidate SCG for the CPC / CPA procedure is configured to the user equipment (UE), but neither CHO execution nor CPA / CPC execution is initiated for the UE before the failure.

[0034] In some embodiments, the failure is defined as a too-late CHO comprising a target MCG and a candidate SCG for CPC / CPA.

[0035] In some embodiments, the situation is one of the following: a CHO execution condition of a CHO candidate primary cell (PCell) is satisfied, but a CPA / CPC execution condition of a CPAC candidate PSCell is not satisfied; the CHO execution condition of the CHO candidate PCell is first satisfied, and the CPA / CPC execution condition of the CPAC candidate PSCell is secondly satisfied, but the CPAC candidate PSCell is not associated with the CHO candidate PCell; the CHO execution condition of the CHO candidate PCell is first satisfied, and when the CPA / CPC execution condition of the CPAC candidate PSCell is secondly satisfied, a leaving condition of the CHO candidate PCell is met; The CPAC execution condition of the CPAC candidate PSCell is met, but the CHO execution condition of the CHO candidate PCell is not met; the CPAC execution condition of the CPAC candidate PSCell is first met, and the CHO execution condition of the CHO candidate PCell is secondly met, but the CHO candidate PCell is not associated with the CPAC candidate PSCell; the CPAC execution condition of the CPAC candidate PSCell is first met, and when the CHO execution condition of the CHO candidate PCell is secondly met, the leaving condition of the CPAC candidate PSCell is met; and the CHO execution condition is not met, and the CPAC execution condition is not met.

[0036] In some embodiments, the failure occurs in one of the following situations: CPAC execution fails or SCG failure occurs shortly after the CPAC execution is successfully completed; CHO execution fails or MCG failure occurs shortly after the CHO execution is successfully completed; and the CHO execution fails or the MCG failure occurs shortly after the CHO execution is successfully completed, and the CPAC execution fails or the SCG failure occurs shortly after the CPAC execution is successfully completed.

[0037] Some embodiments of the present application provide a candidate secondary node (SN). The candidate SN includes a transceiver and a processor coupled to the transceiver, wherein the processor is configured to cause the candidate SN to perform at least one of the following: receiving information indicating that one or more conditional primary secondary cell group cell (PSCell) addition or change (CPAC) candidate PSCells are erroneously selected, wherein the information is received from a source master node (MN), a candidate MN, or a source SN; or modifying the one or more CPAC candidate PSCells.

[0038] In some embodiments, the information is received in the event of a failure in one of: a CPAC procedure; and a CHO including a target master cell group (MCG) and candidate SCGs for a conditional PSCell change / conditional PSCell add (CPC / CPA) procedure.

[0039] In some embodiments, the failure is one of: secondary cell group (SCG) failure, radio link failure (RLF), and CPAC execution failure.

[0040] In some embodiments, the failure occurs when configuration information related to the CHO including the target MCG and candidate SCG for the CPC / CPA procedure is configured to the user equipment (UE), but neither CHO execution nor CPA / CPC execution is initiated for the UE before the failure.

[0041] In some embodiments, the failure is defined as a too-late CHO comprising a target MCG and a candidate SCG for CPC / CPA.

[0042] In some embodiments, the situation is one of the following: a CHO execution condition of a CHO candidate primary cell (PCell) is satisfied, but a CPA / CPC execution condition of a CPAC candidate PSCell is not satisfied; the CHO execution condition of the CHO candidate PCell is first satisfied, and the CPA / CPC execution condition of the CPAC candidate PSCell is secondly satisfied, but the CPAC candidate PSCell is not associated with the CHO candidate PCell; the CHO execution condition of the CHO candidate PCell is first satisfied, and when the CPA / CPC execution condition of the CPAC candidate PSCell is secondly satisfied, a leaving condition of the CHO candidate PCell is met; The CPAC execution condition of the CPAC candidate PSCell is met, but the CHO execution condition of the CHO candidate PCell is not met; the CPAC execution condition of the CPAC candidate PSCell is first met, and the CHO execution condition of the CHO candidate PCell is secondly met, but the CHO candidate PCell is not associated with the CPAC candidate PSCell; the CPAC execution condition of the CPAC candidate PSCell is first met, and when the CHO execution condition of the CHO candidate PCell is secondly met, the leaving condition of the CPAC candidate PSCell is met; and the CHO execution condition is not met, and the CPAC execution condition is not met.

[0043] In some embodiments, the failure occurs in one of the following situations: CPAC execution fails or SCG failure occurs shortly after the CPAC execution is successfully completed; CHO execution fails or MCG failure occurs shortly after the CHO execution is successfully completed; and the CHO execution fails or the MCG failure occurs shortly after the CHO execution is successfully completed, and the CPAC execution fails or the SCG failure occurs shortly after the CPAC execution is successfully completed.

[0044] Some embodiments of the present application provide a user equipment (UE). The UE includes a transceiver and a processor coupled to the transceiver, wherein the processor is configured to cause the UE to: store failure-related information associated with a failure, wherein the failure occurs in a conditional handover (CHO) including a target primary cell group (MCG) and a candidate secondary cell group (SCG) for a conditional primary secondary cell group (PSCell) change / conditional PSCell add (CPC / CPA) procedure; and transmit the failure-related information.

[0045] In some embodiments, the failure-related information includes at least one of the following: a first type of execution condition that is met; a second type of execution condition that is met; information indicating whether the CPAC execution condition of a conditional PSCell addition or change (CPAC) candidate PSCell is met; information indicating whether the CHO execution condition of a CHO candidate PCell is met; information indicating whether the candidate PSCell that meets the CPAC execution condition is associated with a candidate primary cell (PCell) that meets the CHO execution condition; information indicating whether a leaving condition of the candidate PCell that meets the CHO execution condition is met, for example, when the CPAC execution condition of the CPAC candidate PSCell is met; information indicating whether a leaving condition of the candidate PSCell that meets the CPAC execution condition is met, for example, when the CHO execution condition of the CHO candidate PCell is met; a time elapsed from when the CHO execution condition is met until the CPAC execution condition is met; or a time elapsed from when the CPAC execution condition is met until the CHO execution condition is met.

[0046] In some embodiments, the failure is one of: MCG failure; SCG failure; radio link failure (RLF); CHO execution failure; and conditional PSCell add or change (CPAC) execution failure.

[0047] In some embodiments, the processor is configured to cause the UE to receive configuration information related to the CHO including a target MCG and candidate SCG for a CPC / CPA procedure, and wherein the failure occurs when: the configuration information is received, but neither CHO execution nor CPA / CPC execution is initiated for the UE before the failure.

[0048] In some embodiments, the failure is defined as a too-late CHO comprising a target MCG and a candidate SCG for CPC / CPA.

[0049] In some embodiments, the situation is one of the following: the CHO execution condition of the CHO candidate PCell is met, but the CPA / CPC execution condition of the conditional PSCell addition or change (CPAC) candidate PSCell is not met; the CHO execution condition of the CHO candidate PCell is first met, and the CPA / CPC execution condition of the CPAC candidate PSCell is secondly met, but the CPAC candidate PSCell is not associated with the CHO candidate PCell; the CHO execution condition of the CHO candidate PCell is first met, and when the CPA / CPC execution condition of the CPAC candidate PSCell is secondly met, the CHO candidate PCell is met. Leaving condition; satisfying the CPAC execution condition of the CPAC candidate PSCell, but not satisfying the CHO execution condition of the CHO candidate PCell; first satisfying the CPAC execution condition of the CPAC candidate PSCell, and secondly satisfying the CHO execution condition of the CHO candidate PCell, but the CHO candidate PCell is not associated with the CPAC candidate PSCell; first satisfying the CPAC execution condition of the CPAC candidate PSCell, and when secondly satisfying the CHO execution condition of the CHO candidate PCell, meeting the leaving condition of the CPAC candidate PSCell; and not satisfying the CHO execution condition, and not satisfying the CPAC execution condition.

[0050] In some embodiments, the failure occurs in one of the following situations: CPAC execution fails or SCG failure occurs shortly after the CPAC execution is successfully completed; CHO execution fails or MCG failure occurs shortly after the CHO execution is successfully completed; and the CHO execution fails or the MCG failure occurs shortly after the CHO execution is successfully completed, and the CPAC execution fails or the SCG failure occurs shortly after the CPAC execution is successfully completed.

[0051] Some embodiments of the present application provide a method performed by a network node, the method comprising: obtaining information for recovering a cell that failed when a failure occurs in one of the following: a conditional handover (CHO) procedure, a conditional primary and secondary cell group cell (PSCell) add or change (CPAC) procedure, and a CHO including a target primary cell group (MCG) and a candidate secondary cell group (SCG) for a conditional PSCell change / conditional PSCell add (CPC / CPA) procedure; and performing analysis on the failure.

[0052] Some embodiments of the present application provide a method performed by a candidate secondary node (SN). The method includes performing at least one of the following: receiving information indicating that one or more conditional primary secondary cell group cell (PSCell) addition or change (CPAC) candidate PSCells were erroneously selected, wherein the information is received from a source master node (MN), a candidate MN, or a source SN; or modifying the one or more CPAC candidate PSCells.

[0053] Some embodiments of the present application provide a method performed by a UE, the method comprising: storing failure-related information associated with a failure, wherein the failure occurs in a conditional handover (CHO) including a target primary cell group (MCG) and a candidate secondary cell group (SCG) for a conditional primary secondary cell group (PSCell) change / conditional PSCell add (CPC / CPA) procedure; and transmitting the failure-related information.

[0054] Some embodiments of the present application provide a device for wireless communication. The device includes: a non-transitory computer-readable medium having computer-executable instructions stored thereon; a receiving circuit system; a transmitting circuit system; and a processor coupled to the non-transitory computer-readable medium, the receiving circuit system, and the transmitting circuit system, wherein the computer-executable instructions cause the processor to implement the above-described method performed by a UE or a network node (source MN, candidate MN, source SN, or candidate SN).

[0055] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to describe the manner in which the advantages and features of the present application can be obtained, the description of the present application is presented by reference to specific embodiments of the present application illustrated in the accompanying drawings. These drawings depict only example embodiments of the present application and are therefore not to be considered limiting of its scope.

[0057] Figure 1 A schematic diagram illustrating a wireless communication system according to some embodiments of the present application.

[0058] Figure 2 An exemplary procedure for performing failure analysis according to some embodiments of the present application is described.

[0059] Figure 3 An exemplary procedure performed by a candidate SN according to some embodiments of the present application is described.

[0060] Figure 4 An exemplary procedure performed by a UE according to some embodiments of the present application is described.

[0061] Figure 5 A block diagram illustrating an exemplary apparatus according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0062] The detailed description of the accompanying drawings is intended as a description of the preferred embodiments of the present application and is not intended to represent the only form in which the present application can be practiced. It should be understood that the same or equivalent functions can be accomplished by different embodiments that are intended to be included in the spirit and scope of the present application.

[0063] Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, the embodiments are provided in the context of specific network architectures and new service scenarios (e.g., 3GPP 5G, 3GPP LTE Release 8, etc.). It is contemplated that as network architectures and new service scenarios evolve, all embodiments in this application are also applicable to similar technical problems; and further, the terminology used in this application may change without affecting the principles of this application.

[0064] Figure 1 A schematic diagram illustrating a wireless communication system according to some embodiments of the present application.

[0065] like Figure 1 , the wireless communication system 100 may be a dual connectivity system 100 including at least one UE 101, at least one MN 102, and at least one SN 103. Specifically, for illustration purposes, Figure 1 The dual connectivity system 100 in FIG. 1 includes one shown UE 101, one shown MN 102, and one shown SN 103. Figure 1 A specific number of UEs 101, MNs 102, and SNs 103 are depicted in FIG. 1 , but it is contemplated that any number of UEs 101, MNs 102, and SNs 103 may be included in the wireless communication system 100.

[0066] refer to Figure 1, UE 101 may be connected to MN 102 and SN 103 via a network interface (e.g., a Uu interface as specified in a 3GPP standard document). MN 102 and SN 103 may be connected to each other via a network interface (e.g., an Xn interface as specified in a 3GPP standard document for NR-NR DC, NGEN-DC, or NE-DC, or an X2 interface as specified in a 3GPP standard document for EN-DC). MN 102 may be connected to SN 103 via a network interface ( Figure 1 UE 102 may be configured to utilize resources provided by MN 102 and SN 103 to perform data transmission.

[0067] MN 102 may refer to a radio access node that provides a control plane connection to a core network. In an embodiment of the present application, in an E-UTRA-NR dual connectivity (EN-DC) scenario, MN 102 may be an eNB. In another embodiment of the present application, in a next-generation E-UTRA-NR dual connectivity (NGEN-DC) scenario, MN 102 may be an ng-eNB. In yet another embodiment of the present application, in an NR-E-UTRA dual connectivity (NE-DC) scenario or an NR-NR dual connectivity (NR-DC) scenario, MN 102 may be a gNB.

[0068] MN 102 may be associated with a Master Cell Group (MCG). MCG may refer to a serving cell group associated with MN 102 and may include a primary cell (PCell) of the MCG and optionally one or more secondary cells (SCells). The PCell may provide control plane connectivity to UE 101.

[0069] SN 103 may refer to a radio access node that does not have a control plane connection to the core network but provides additional resources to UE 101. In an embodiment of the present application, in an EN-DC scenario, SN 103 may be an en-gNB. In another embodiment of the present application, in an NE-DC scenario, SN 103 may be an ng-eNB. In yet another embodiment of the present application, in an NR-DC scenario or an NGEN-DC scenario, SN 103 may be a gNB.

[0070] SN 103 may be associated with a secondary cell group (SCG). An SCG may refer to a serving cell group associated with SN 103 and may include a primary secondary 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).

[0071] In some embodiments of the present application, UE 101 may include a computing device, such as a desktop computer, a laptop computer, a personal digital assistant (PDA), a tablet computer, a smart TV (e.g., a TV connected to the Internet), a set-top box, a game console, a security system (including a security camera), an in-vehicle computer, a network device (e.g., a router, a switch, and a modem), or the like. In some other embodiments of the present application, UE 101 may include a portable wireless communication device, a smart phone, a cellular phone, a flip phone, a device with a subscriber identity module, a personal computer, a selective call reception circuit system, or any other device capable of sending and receiving communication signals on a wireless network.

[0072] In some other embodiments of the present application, UE 101 may include a wearable device, such as a smart watch, a fitness band, an optical head-mounted display, or the like. In addition, UE 101 may be referred to as a subscriber unit, a mobile device, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terms used in the art.

[0073] Generally speaking, CHO is performed by the UE when at least one CHO execution condition is reached, met or satisfied. For example, when one or two CHO execution conditions of the candidate PCell are met or satisfied, CHO execution is performed, and "CHO ​​execution" may be an operation in which the UE determines the candidate PCell that meets the CHO execution conditions as the target PCell, and performs a PCell change or handover with the target PCell (for example, the UE performs a RA procedure towards the target PCell). The UE starts evaluating the CHO execution conditions upon receiving the CHO configuration, and stops the CHO execution condition evaluation once at least one CHO execution condition is reached or satisfied. The CHO configuration contains the configuration of the CHO candidate PCell generated by the candidate BS (for example, the candidate (target) MN) and the CHO execution conditions generated by the source BS (for example, the source MN).

[0074] CPAC is executed by the UE when one or more CPAC execution conditions are reached, met or satisfied. For example, when at least one CPAC execution condition of a candidate PSCell is met or satisfied, CPAC execution is performed, and "CPAC execution" may be an operation in which the UE determines the candidate PSCell that meets the CPAC execution conditions as the target PSCell, and performs PSCell addition or change with the target PSCell (for example, the UE performs a RA procedure towards the target PSCell). The UE starts evaluating the CPAC execution conditions upon receiving the CPAC configuration, and stops evaluating the CPAC execution conditions once at least one CPAC execution condition is reached or satisfied. The CPAC configuration (i.e., CPA or CPC configuration) contains the configuration of the CPAC candidate PSCell generated by the candidate (target) SN and the CPAC execution conditions generated by the source SN or source MN.

[0075] One goal of mobility enhancement in 3GPP Rel-18 is to specify a CHO that includes a target MCG and candidate SCGs for CPC / CPA procedures. A CHO that includes a target MCG and candidate SCGs for CPC / CPA procedures may also be named "CHO ​​that includes a candidate (target) MCG and candidate (target) SCG for CPC / CPA procedures," "CHO ​​that includes a target MCG and candidate SCGs for CPA procedures, or CHO that includes a target MCG and candidate SCGs for CPC procedures," "CHO ​​with candidate SCG procedures," or the like. For example, for a CHO that includes a target MCG and candidate SCGs for CPC / CPA procedures, the following scenarios may be considered:

[0076] (1) Scenario 1 "CHO ​​with CPA": CHO from single connectivity to MR-DC connectivity, for example, CHO from source PCell 1 to candidate (target) PCell 2 with a candidate (target) SN. That is, in Scenario 1, single connectivity is changed to dual connectivity.

[0077] (2) Scenario 2 "CHO ​​with intra-SN CPC": For example, CHO from source PCell 1 with SCG 1 in SN 1 to candidate (target) PCell 2 with candidate (target) SCG in the same SN 1. That is, in scenario 2, the PCell is changed, the PSCell is changed, but the SN is not changed.

[0078] (3) Scenario 3 "CHO ​​with Inter-SN CPC": CHO from source PCell 1 (e.g., managed by an S-MN) with SN 1 (e.g., S-SN) to candidate (target) PCell 2 (e.g., managed by a T-MN) with a candidate (target) SN other than SN 1 (e.g., T-SN). In other words, in Scenario 3, both the PCell and the SN are changed.

[0079] In a CHO that includes a target MCG and candidate SCGs for CPC / CPA procedures, CHO configurations involving or including CPC or CPA configurations (intended to be applied together) can be supported. In a CHO that includes a target MCG and candidate SCGs for CPC / CPA procedures, one or more CHO candidate PCells can be configured, wherein one or two CHO execution conditions can be configured for each CHO candidate PCell; one or more associated CPAC candidate PSCells can be configured for each CHO candidate PCell; and one or two CPAC execution conditions can be configured for each CPAC candidate PSCell.

[0080] In a CHO that includes a target MCG and candidate SCGs for CPC / CPA procedures, CHO execution condition evaluation and CPC / CPA execution condition evaluation may be concurrent or simultaneous. For example, the UE may simultaneously start evaluating the execution conditions of the CHO candidate PCell and the execution conditions of the CPCA candidate PSCell (e.g., upon receiving a configuration for a CHO with candidate SCG procedures).

[0081] When the UE receives a configuration for CHO including a target MCG and candidate SCG for CPC / CPA procedures (i.e., a CHO configuration involving or including a CPC or CPA configuration, or a configuration for CHO with a candidate SCG procedure), for example, when the UE receives a configuration for a CHO candidate (target) PCell, CHO execution conditions, a configuration for a CPAC candidate (target) PSCell, and CPAC execution conditions, the CHO evaluation and the CPC or CPA evaluation may be concurrent. For example, the UE starts evaluating the CHO execution conditions of the candidate (target) PCell and the CPAC execution conditions of the candidate (target) PSCell (when receiving the configuration for CHO with a candidate SCG procedure) at the same time. The UE does not perform CPC or CPA unless the CHO execution conditions of the CHO candidate PCell are met. The UE does not need to unpack any nested conditional configuration containers to perform measurements.

[0082] In the CHO including the target MCG and candidate SCG for the CPC / CPA procedure, the UE evaluates whether the CHO execution conditions and / or CPC / CPA execution conditions are met. If any of the CHO execution conditions and CPC / CPA execution conditions are not met, or if any of the CHO execution and CPC / CPA execution fails, MCG failure and / or SCG failure will occur.

[0083] Currently, in the above scenario, several issues need to be addressed. To improve mobility robustness, the MRO mechanism for the CHO containing the target MCG and candidate SCGs for CPC / CPA procedures should be considered, including, for example, what information the network node needs from the UE to perform MRO to modify the configuration of the CHO containing the target MCG and candidate SCGs for CPC / CPA procedures, and how the network node performs root cause analysis for MRO purposes.

[0084] The embodiments of the present disclosure are intended to solve such problems in the above-mentioned scenarios. For example, some embodiments define "too late CHO with candidate SCG procedure" or define "too late CHO with CPA / CPC execution". In some embodiments, in order to implement MRO analysis of CHO including target MCG and candidate SCG for CPC / CPA procedure, the UE needs to store and report failure-related information. Some embodiments provide methods for network MRO analysis in the event of MCG failure or RLF or CHO execution failure. Some embodiments provide methods for network MRO analysis in the event of SCG failure or RLF or CPAC execution failure. More details about the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0085] Figure 2 An exemplary procedure for performing failure analysis according to some embodiments of the present application is described. Figure 2 The exemplary procedure 200 in the embodiment of the present invention may be performed by a network node, such as a source MN (S-MN), a candidate (target) MN or a source SN (S-SN), such as Figure 1 Although described with respect to a network node, it should be understood that other devices may be configured to perform the same Figure 2 A similar approach to the one in the previous section.

[0086] In such Figure 2 In the exemplary procedure 200 shown in FIG, in operation 201, when a failure occurs in one of the following: a CHO procedure, a CPAC procedure, and a CHO including a target MCG and candidate SCG for the CPC / CPA procedure, the network node may obtain information for recovering the failed cell. In operation 202, the network node may perform analysis on the failure.

[0087] In some embodiments, the network node is a source MN (a node managing a source PCell), and, for example, in the event of an SCG failure or RLF or CPAC execution failure, the source MN may perform at least one of the following operations:

[0088] (1) Modify the CPAC candidate PSCell list.

[0089] (2) Transmitting information to at least one candidate SN to indicate that one or more CPAC candidate PSCells are incorrectly selected. For example, the source MN may transmit a message to one or more candidate SNs to indicate that one or more CPAC candidate PSCells are incorrectly selected. The message may be an existing Xn or X2 message, or a newly introduced Xn or X2 message. For another example, the source MN may transmit an indication to one or more candidate SNs to indicate that one or more CPAC candidate PSCells are incorrectly selected. The indication may be included in an existing Xn or X2 message, or in a newly introduced Xn or X2 message.

[0090] (3) Instructing one or more candidate MNs to transmit information to at least one candidate SN to indicate that one or more CPAC candidate PSCells are incorrectly selected. For example, in an embodiment, the source MN may first transmit message X to one or more candidate MNs (optionally, ID information of one or more candidate SNs may be included in message X; and message X may be an existing Xn or X2 message, or a newly introduced Xn or X2 message), and then, the one or more candidate MNs may transmit message Y to the corresponding candidate SNs to indicate that one or more CPAC candidate PSCells are incorrectly selected (message Y may be an existing Xn or X2 message, or a newly introduced Xn or X2 message). As another example, the source MN may transmit an indication P to one or more candidate MNs respectively to instruct the candidate MNs to notify one or more candidate SNs that one or more CPAC candidate PSCells are incorrectly selected, and then, the one or more candidate MNs may transmit an indication Q to one or more candidate SNs respectively to indicate that one or more CPAC candidate PSCells are incorrectly selected (the indication P or Q may be included in an existing Xn or X2 message, or included in a newly introduced Xn or X2 message).

[0091] (4) Optimize a set of CPAC execution conditions.

[0092] (5) Transmitting information to one or more candidate MNs to indicate that the set of CPAC execution conditions is improperly configured.

[0093] In an embodiment, the cell is a PSCell for recovery failure, and if the PSCell is not included in the CPAC candidate PSCell list suggested or provided by the source MN, the source MN may modify the CPAC candidate PSCell list.

[0094] In an embodiment, the cell is a PSCell for recovery failure, and if the PSCell is included in a CPAC candidate PSCell list suggested or provided by the source MN, but is not included in another CPAC candidate PSCell list selected or prepared by the candidate SN:

[0095] (1) The source MN may transmit information to the candidate SN to indicate that another CPAC candidate PSCell list selected or provided by the candidate SN is inappropriate; for example, this information may be a message or may be indication information included in a message; for example, the source MN may transmit such information to one or more candidate SNs respectively; or

[0096] (2) The source MN may instruct one or more candidate MNs to transmit information to the candidate SNs indicating that another CPAC candidate PSCell list selected or prepared by the candidate SN is inappropriate. For example, the source MN may first transmit messages to the one or more candidate MNs to inform them to indicate to the one or more candidate SNs that one or more CPAC candidate PSCells are incorrectly selected (optionally, ID information of the one or more candidate SNs may be included in the message; and the message may be an existing Xn or X2 message, or a newly introduced Xn or X2 message), and then, the one or more candidate MNs may transmit messages to the corresponding candidate SNs to indicate that one or more CPAC candidate PSCells are incorrectly selected (the message may be an existing Xn or X2 message, or a newly introduced Xn or X2 message). As another example, the source MN may transmit indications to one or more candidate MNs respectively to instruct the candidate MNs to notify one or more candidate SNs that one or more CPAC candidate PSCells are incorrectly selected, and then, the one or more candidate MNs may transmit indications to one or more candidate SNs respectively to indicate that one or more CPAC candidate PSCells are incorrectly selected (the indications may be included in existing Xn or X2 messages, or included in newly introduced Xn or X2 messages).

[0097] In an embodiment, the cell is a PSCell for recovering a failure, and if the PSCell is included in a CPAC candidate PSCell list selected or prepared by a candidate SN, the source MN may optimize a set of CPAC execution conditions for the CPAC candidate PSCell list, or the source MN may transmit information to one or more candidate MNs to indicate that the set of CPAC execution conditions is improperly configured.

[0098] In some embodiments, the network node is a source MN, and, for example, in the event of an MCG failure or RLF or CHO execution failure, the source MN may perform at least one of the following operations:

[0099] (1) Modify the CHO candidate PCell list;

[0100] (2) Transmitting information to at least one candidate MN to indicate that one or more CHO candidate PCells are incorrectly selected. For example, the source MN may transmit a message to each of the one or more candidate MNs to indicate that one or more CHO candidate PCells are incorrectly selected. The message may be an existing Xn or X2 message, or a newly introduced Xn or X2 message. For another example, the source MN may transmit an indication to each of the one or more candidate MNs to indicate that one or more CHO candidate PCells are incorrectly selected. The indication may be included in an existing Xn or X2 message, or included in a newly introduced Xn or X2 message.

[0101] (3) Optimize a set of CHO execution conditions.

[0102] In an embodiment, the cell is a PCell for failure recovery, and if the PCell is not included in the CHO candidate PCell list suggested or provided by the source MN, the source MN may modify the CHO candidate PCell list.

[0103] In an embodiment, if a cell is a PCell for failure recovery and the PCell is included in a CHO candidate PCell list suggested or provided by a source MN but not included in another CHO candidate PCell list selected or prepared by a candidate MN, the source MN may transmit information to the candidate MN indicating that the other CHO candidate PCell list selected or prepared by the candidate MN is inappropriate. For example, this information may be a message or may be indication information included in a message. For example, the source MN may transmit such information separately to one or more candidate MNs.

[0104] In an embodiment, the cell is a PCell for failure recovery, and if the PCell is included in a CHO candidate PCell list selected or prepared by a candidate MN, the source MN may optimize a set of CHO execution conditions for the CHO candidate PCell list.

[0105] In some embodiments, the source MN may determine cell information, transmit cell information, or receive cell information. In an embodiment, if the cell is a PCell for failure recovery, or if the cell is a PSCell for recovery failure, the source MN may obtain the cell information by determining the cell information, for example, in operation 201. Optionally, after determining the cell information, the source MN may transmit the cell information to, for example, one or more candidate MNs. In another embodiment, if the cell information is determined by another node (e.g., one or more candidate MNs or the source SN), the source MN may receive the cell information from the other node (e.g., one or more candidate MNs or the source SN), for example, in operation 201.

[0106] In some embodiments, the source MN may transmit failure-related information associated with the failure (denoted as failure-related information #1 for simplicity) to, for example, one or more candidate MNs or the source SN. In some other embodiments, the source MN may receive the failure-related information associated with the failure, for example, from the source SN or at least one candidate MN or a receiving network node (e.g., a third-party node different from the source MN or the source SN). The failure-related information may be stored, generated, or sent by the UE.

[0107] In an embodiment, the failure-related information (e.g., failure-related information #1) may include at least one of the following:

[0108] (1) The type of the first satisfied or triggered execution condition or conditional event; for example, the type may be CHO execution condition / CHO conditional event or CPAC execution condition / CPAC conditional event;

[0109] (2) the type of the second execution condition or conditional event that is satisfied or triggered; for example, the type may be CHO execution condition / CHO conditional event or CPAC execution condition / CPAC conditional event;

[0110] (3) Information indicating whether one or two CPAC execution conditions of the CPAC candidate PSCell are satisfied or triggered, for example, if one or two CHO execution conditions of the CHO candidate PCell are satisfied or triggered first;

[0111] (4) Information indicating whether one or two CHO execution conditions of the CHO candidate PCell are satisfied or triggered, for example, if one or two CPAC execution conditions of the CPAC candidate PSCell are satisfied or triggered first;

[0112] (5) Cell information of the source PCell, for example, the cell information may include PCI, carrier frequency information (e.g., ARFCN) and / or CGI-info (e.g., PLMN-identity, cell identity, and TrackingAreaCode);

[0113] (6) Cell information of the failed PCell;

[0114] (7) Cell information of the source PSCell;

[0115] (8) Cell information of the failed PSCell.

[0116] In an embodiment, if both the CHO execution condition and the CPAC execution condition are satisfied, then the failure-related information #1 may include at least one of the following:

[0117] (1) Information indicating whether a candidate PSCell that satisfies a CPAC execution condition (i.e., a CPAC candidate PSCell whose CPAC execution condition has been satisfied or triggered) is associated with a candidate PCell that satisfies a CHO execution condition (i.e., a CHO candidate PCell whose CHO execution condition has been satisfied or triggered);

[0118] (2) information indicating whether a leaving condition of a candidate PCell that meets a CHO execution condition is satisfied, for example, when one or two CPAC execution conditions of a CPAC candidate PSCell are satisfied or triggered;

[0119] (3) Information indicating whether a leaving condition of a candidate PSCell that meets the CPAC execution condition is satisfied, for example, when one or two CHO execution conditions of a CHO candidate PCell are satisfied or triggered;

[0120] (4) the time elapsed from the time one or both CHO execution conditions of the CHO candidate PCell are satisfied or triggered until the time one or both CPAC execution conditions of the CPAC candidate PSCell are satisfied or triggered; or

[0121] (5) The time elapsed from the time when one or two CPAC execution conditions of the CPAC candidate PSCell are satisfied or triggered until the time when one or two CHO execution conditions of the CHO candidate PCell are satisfied or triggered.

[0122] In some embodiments, the network node is a candidate MN (a node that manages one or more CHO candidate PCells), and, for example, in the event of an SCG failure or RLF or CPAC execution failure, the candidate MN may perform at least one of the following operations:

[0123] (1) Modify the CPAC candidate PSCell list;

[0124] (2) Transmitting information to at least one candidate SN to indicate that one or more CPAC candidate PSCells are incorrectly selected. For example, the candidate MN may transmit a message to one or more candidate SNs to indicate that one or more CPAC candidate PSCells are incorrectly selected. The message may be an existing Xn or X2 message, or a newly introduced Xn or X2 message. For another example, the source MN may transmit an indication to one or more candidate SNs to indicate that one or more CPAC candidate PSCells are incorrectly selected. The indication may be included in an existing Xn or X2 message, or in a newly introduced Xn or X2 message.

[0125] (3) Optimize a set of CPAC execution conditions; or

[0126] (4) Transmitting information to the source MN to indicate that the set of CPAC execution conditions is improperly configured.

[0127] In an embodiment, the cell is a PSCell for recovery failure, and if the PSCell is not included in the CPAC candidate PSCell list suggested or provided by the candidate MN, the candidate MN may modify the CPAC candidate PSCell list.

[0128] In an embodiment, the cell is a PSCell for recovery failure, and if the PSCell is included in a CPAC candidate PSCell list suggested or provided by a candidate MN but is not included in another CPAC candidate PSCell list selected or prepared by a candidate SN, the candidate MN may transmit information to the candidate SN indicating that the other CPAC candidate PSCell list selected or prepared by the candidate SN is inappropriate. For example, this information may be a message or may be indication information included in a message, and the candidate MN may transmit such information to one or more candidate SNs respectively.

[0129] In an embodiment, the cell is a PSCell for recovering a failure, and if the PSCell is included in a CPAC candidate PSCell list selected or prepared by a candidate SN, the candidate MN may optimize a set of CPAC execution conditions for the CPAC candidate PSCell list, or the candidate MN may transmit information to the source MN to indicate that the set of CPAC execution conditions is improperly configured.

[0130] In an embodiment, for example, in the event of an MCG failure or RLF or CHO execution failure, the candidate MN may perform at least one of the following operations:

[0131] (1) receiving information from the source MN indicating that at least one CHO candidate PCell is incorrectly selected. For example, the candidate MN may receive a message from the source MN indicating that one or more CHO candidate PCells are incorrectly selected. The message may be an existing Xn or X2 message, or a newly introduced Xn or X2 message. For another example, the candidate MN may receive an indication from the source MN indicating that one or more CHO candidate PCells are incorrectly selected. The indication may be included in an existing Xn or X2 message, or included in a newly introduced Xn or X2 message; or

[0132] (2) Modify one or more CHO candidate PCells selected or prepared by the candidate MN.

[0133] In some embodiments, the candidate MN may determine cell information, transmit cell information, or receive cell information. In an embodiment, the candidate MN may obtain cell information by determining cell information, for example, in operation 201. Optionally, after determining the cell information, the candidate MN may transmit the cell information to the source MN. In another embodiment, if the cell information is determined by another node (e.g., the source MN or the source SN), the candidate MN may receive the cell information from the other node (e.g., the source MN or the source SN) in operation 201 to obtain the cell information.

[0134] In some embodiments, the candidate MN may receive failure-related information associated with the failure from the source MN, such as failure-related information #1 described above. In some other embodiments, the candidate MN may receive failure-related information associated with the failure from one or more candidate SNs, such as failure-related information #1 described above.

[0135] In some embodiments, the network node is a source SN (a node that manages a source PSCell), and, for example, in the event of an SCG failure or RLF or CPAC execution failure, the source SN may perform at least one of the following operations:

[0136] (1) Modify the CPAC candidate PSCell list;

[0137] (2) Transmitting information to at least one candidate SN to indicate that one or more CPAC candidate PSCells are incorrectly selected; for example, the source SN may transmit a message to one or more candidate SNs to indicate that one or more CPAC candidate PSCells are incorrectly selected. The message may be an existing Xn or X2 message, or a newly introduced Xn or X2 message. For another example, the source SN may transmit an indication to one or more candidate SNs to indicate that one or more CPAC candidate PSCells are incorrectly selected. The indication may be included in an existing Xn or X2 message, or in a newly introduced Xn or X2 message;

[0138] (3) Instructing the source MN to transmit information indicating that one or more CPAC candidate PSCells are erroneously selected to at least one candidate SN. For example, the source SN may first transmit a message to the source MN to notify the source MN to indicate to one or more candidate SNs that one or more CPAC candidate PSCells are erroneously selected (optionally, ID information of the one or more candidate SNs may be included in the message; and the message may be an existing Xn or X2 message, or a newly introduced Xn or X2 message), and then, the source MN may transmit messages to the corresponding candidate SNs respectively to indicate that one or more CPAC candidate PSCells are erroneously selected (the message may be an existing Xn or X2 message, or a newly introduced Xn or X2 message). For another example, the source SN may transmit an indication to the source MN to instruct the source MN to notify one or more candidate SNs that one or more CPAC candidate PSCells are erroneously selected, and then the source MN may transmit an indication to the one or more candidate SNs respectively to indicate that the one or more CPAC candidate PSCells are erroneously selected (the indication may be included in an existing Xn or X2 message, or included in a newly introduced Xn or X2 message); or

[0139] (4) Optimize a set of CPAC execution conditions.

[0140] In an embodiment, the cell is a PSCell for recovery failure, and if the PSCell is not included in the CPAC candidate PSCell list suggested or provided by the source SN, the source SN may modify the CPAC candidate PSCell list.

[0141] In some embodiments, the cell is a PSCell for recovery failure, and if the PSCell is included in a CPAC candidate PSCell list suggested or provided by a source SN, but is not included in another CPAC candidate PSCell list selected or prepared by a candidate SN:

[0142] (1) The source SN may transmit information to the candidate SN to indicate that another CPAC candidate PSCell list selected or prepared by the candidate SN is not suitable; for example, the information may be a message or may be indication information included in a message, and the source SN may transmit such information to one or more candidate SNs respectively; or

[0143] (2) The source SN may instruct the source MN to transmit information to the candidate SN to indicate that another CPAC candidate PSCell list selected or prepared by the candidate SN is inappropriate. For example, the source SN may first transmit a message to the source MN to notify the source MN to indicate to one or more candidate SNs that one or more CPAC candidate PSCells are incorrectly selected (optionally, ID information of one or more candidate SNs may be included in the message, and the message may be an existing Xn or X2 message, or a newly introduced Xn or X2 message), and then, the source MN may transmit messages to the corresponding candidate SNs respectively to indicate that one or more CPAC candidate PSCells are incorrectly selected (the message may be an existing Xn or X2 message, or a newly introduced Xn or X2 message). As another example, the source SN may transmit an indication to the source MN to instruct the source MN to notify one or more candidate SNs that one or more CPAC candidate PSCells are incorrectly selected, and then, the source MN may transmit an indication to the one or more candidate SNs respectively to indicate that one or more CPAC candidate PSCells are incorrectly selected (the indication may be included in an existing Xn or X2 message, or included in a newly introduced Xn or X2 message).

[0144] In an embodiment, the cell is a PSCell for recovery failure, and if the PSCell is included in a CPAC candidate PSCell list selected or prepared by the candidate SN, the source SN may optimize a set of CPAC execution conditions for the CPAC candidate PSCell list.

[0145] In some embodiments, the source SN may determine the cell information, transmit the cell information, or receive the cell information. In an embodiment, the source SN may obtain the cell information by, for example, determining the cell information in operation 201. Optionally, after determining the cell information, the source SN may transmit the cell information to, for example, the source MN. In another embodiment, if the cell information is determined by the source MN, the source SN may receive the cell information from the source MN in operation 201 to obtain the cell information.

[0146] In some embodiments, the source SN may receive failure-related information associated with the failure from the source MN or from a receiving network node (e.g., a third-party node different from the source MN or the source SN), for example, receiving failure-related information #1 as described above. In some embodiments, the failure may be an SCG failure, an MCG failure, an RLF, a CHO execution failure, or a CPAC execution failure.

[0147] In some embodiments, a failure may occur when configuration information related to CHO including a target MCG and candidate SCGs for CPC / CPA procedures is configured to a user equipment (UE), but neither CHO execution nor CPA / CPC execution is initiated for the UE prior to the failure. In an embodiment, a failure is defined as a too-late CHO including a target MCG and candidate SCGs for CPC / CPA.

[0148] In some embodiments, the situation where failure occurs is any of the following situations, situations 1 to 7:

[0149] (1) Case 1: At least one CHO execution condition of the CHO candidate PCell is met, but the CPA / CPC execution condition of the CPAC candidate PSCell is not met;

[0150] (2) Case 2: First, at least one CHO execution condition of the CHO candidate PCell is satisfied, and second, at least one CPA / CPC execution condition of the CPAC candidate PSCell is satisfied, but the CPAC candidate PSCell (e.g., the candidate PSCell that satisfies the CPAC execution condition) is not associated with the CHO candidate PCell (e.g., the candidate PCell that satisfies the CHO execution condition);

[0151] (3) Case 3: First, at least one CHO execution condition of the CHO candidate PCell is satisfied, and when at least one CPA / CPC execution condition of the CPAC candidate PSCell is satisfied, the leaving condition of the CHO candidate PCell is met;

[0152] (4) Case 4: At least one CPAC execution condition of the CPAC candidate PSCell is met, but the CHO execution condition of the CHO candidate PCell is not met;

[0153] (5) Case 5: First, at least one CPAC execution condition of the CPAC candidate PSCell is satisfied, and second, at least one CHO execution condition of the CHO candidate PCell is satisfied, but the CHO candidate PCell (e.g., the candidate PCell that satisfies the CHO execution condition) is not associated with the CPAC candidate PSCell (e.g., the CPAC candidate PSCell that satisfies the CPAC execution condition);

[0154] (6) Case 6: First, at least one CPAC execution condition of the CPAC candidate PSCell is satisfied, and when at least one CHO execution condition of the CHO candidate PCell is satisfied, the leaving condition of the CPAC candidate PSCell is met; and

[0155] (7) Case 7: The CHO execution conditions are not met, and the CPAC execution conditions are not met.

[0156] In some embodiments, failure occurs under any of the following circumstances A through C:

[0157] (1) Case A: The CHO execution conditions and CPAC execution conditions are met, but CPAC execution fails or an SCG failure occurs shortly after CPAC execution successfully completes. In Case A, when CHO execution succeeds, the UE may report failure-related information associated with the failure (e.g., Failure-Related Information #1 described above) to the target MN, for example, via an SCG Failure Information message.

[0158] (2) Case B: The CHO execution conditions and CPAC execution conditions are met, but the CHO execution fails or an MCG failure occurs shortly after the CHO execution is successfully completed. In case B, when the CPAC execution is successful, the UE may report failure-related information associated with the failure (e.g., failure-related information #1 described above) to the target SN, for example, via an MCG Failure Information message.

[0159] (3) Case C: The CHO execution condition and the CPAC execution condition are met, but the CHO execution fails or an MCG failure occurs shortly after the CHO execution is successfully completed, and the CPAC execution fails or an SCG failure occurs shortly after the CPAC execution is successfully completed. In Case C, the UE may report failure-related information associated with the failure (e.g., failure-related information #1 described above), for example, via an RLF report.

[0160] In some embodiments of the present application, in a CHO that includes a target MCG and a candidate SCG for a CPC / CPA procedure (i.e., a CHO with a candidate SCG procedure), CHO execution may be triggered or initiated only when both a CHO execution condition and its associated CPA / CPC execution condition are satisfied, and CPAC (i.e., CPA or CPC) execution may be triggered or initiated only when its associated CHO execution condition is satisfied. A connection failure (e.g., at least one of an MCG failure, an SCG failure, or an RLF) may occur under any of the above-described situations 1 to 7.

[0161] The above situations 1 to 7 may be clarified as “too late CHO with candidate SCG” or “too late CHO including target MCG and candidate SCG for CPA / CPA” or “too late CHO with CPA / CPC execution”. For example, the failure type definition of a failure occurring in a CHO including target MCG and candidate SCG for CPC / CPA procedure may be “too late CHO with candidate SCG” or “too late CHO with CPA / CPC execution” or “too late CHO including target MCG and candidate SCG for CPA / CPA”, where the CHO including target MCG and candidate SCG for CPC / CPA procedure is configured to the UE (or the UE receives the configuration of the CHO with candidate SCG procedure), but neither CHO execution nor CPA / CPC execution is initiated or triggered for the UE before the connection failure.

[0162] Figure 3 An exemplary procedure performed by a candidate SN according to some embodiments of the present application is described. Figure 3 The exemplary process 300 in the embodiment of the present invention may be performed by a candidate (target) SN (a node that manages one or more CPAC candidate PSCells), e.g. Figure 1 Although described with respect to a candidate (target) SN, it should be understood that other devices may be configured to perform the same Figure 3 A similar approach to the one in the previous section.

[0163] In such Figure 3 In the exemplary process 300 shown in FIG, a candidate SN may perform at least one of operations 301 and 302. In operation 301, the candidate SN may receive information indicating that one or more CPAC candidate PSCells were incorrectly selected. The information may be received from a source MN, one or more candidate MNs, or a source SN. In operation 302, the candidate SN may modify one or more CPAC candidate PSCells.

[0164] In some embodiments, in operation 301, if the PSCell used for recovery failure is included in a CPAC candidate PSCell list suggested or provided by the source MN, one or more candidate MNs, or the source SN, but is not included in another CPAC candidate PSCell list selected or prepared by the candidate SN, information may be received from the source MN, one or more candidate MNs, or the source SN. For example, the information in operation 301 may be a message or indication information included in a message, indicating that one or more CPAC candidate PSCells were incorrectly selected.

[0165] In some embodiments, information is received when a failure occurs in a CPAC process or a CHO including a target MCG and a candidate SCG for a CPC / CPA process (i.e., a CHO with a candidate SCG process). For example, the failure may be an SCG failure, an RLF, or a CPAC execution failure.

[0166] In some embodiments, a failure occurs when configuration information related to a CHO including a target MCG and candidate SCGs for CPC / CPA procedures is configured to the UE, but neither CHO execution nor CPA / CPC execution is initiated for the UE before the failure. For example, a failure is defined as "too late CHO including a target MCG and candidate SCGs for CPC / CPA" or "too late CHO with CPA / CPC execution" or "too late CHO with candidate SCGs". In an embodiment, a failure occurs when the configuration information related to a CHO including a target MCG and candidate SCGs for CPC / CPA procedures is configured to the UE, but neither CHO execution nor CPA / CPC execution is initiated for the UE before the failure. Figure 2 In any of the cases 1 to 7 described in the embodiment of . In another embodiment, the failure occurs in the Figure 2 Under any of the situations A to C described in the embodiments.

[0167] In some embodiments, the candidate SN may receive failure-related information associated with the failure (e.g., failure-related information #1) from, for example, the UE, the source MN, the source SN, at least one candidate MN, or a receiving network node (e.g., a third-party node different from the source MN or the source SN). In some other embodiments, the candidate SN may transmit the failure-related information associated with the failure (e.g., failure-related information #1) to, for example, the source MN, the source SN, or at least one candidate MN. The failure-related information may be stored, generated, or sent by the UE.

[0168] Figure 4 An exemplary procedure performed by a UE according to some embodiments of the present application is described. Figure 4 The exemplary procedure 400 in the embodiment of the present invention may be performed by a UE, for example, Figure 1 Although described with respect to a UE, it should be understood that other devices may be configured to perform the same Figure 4 A similar approach to the one in the previous section.

[0169] In such Figure 4 In the exemplary procedure 400 shown in FIG. 4 , in operation 401, the UE may store failure related information associated with the failure, for example, as described above in Figure 2 Failure related information #1 described in the embodiment of FIG. The failure may occur in the CHO including the target MCG and candidate SCG for the CPC / CPA procedure. In operation 402, the UE may transmit the failure related information to, for example, the source MN or the (candidate) target MN or the source SN or the (candidate) target SN or the receiving network node.

[0170] In some embodiments, the failure may be an MCG failure, an SCG failure, an RLF, a CHO execution failure, or a CPAC execution failure.

[0171] In some embodiments, the UE may receive configuration information related to CHO including a target MCG and candidate SCGs for CPC / CPA procedures. A failure may occur when the configuration information is received but neither CHO execution nor CPA / CPC execution is initiated for the UE before the failure. For example, a failure is defined as "too late CHO including a target MCG and candidate SCGs for CPC / CPA" or "too late CHO with CPA / CPC execution" or "too late CHO with candidate SCGs". In an embodiment, a failure occurs when the configuration information is received but neither CHO execution nor CPA / CPC execution is initiated for the UE before the failure. Figure 2 In any of the cases 1 to 7 described in the embodiment of . In another embodiment, the failure occurs in the Figure 2 Under any of the situations A to C described in the embodiments.

[0172] The details described in all other embodiments of the present application are applicable to the operations performed by the UE, source MN, candidate (target) MN, source SN or candidate (target) SN. Figures 2 to 4 In addition, in Figures 2 to 4 The details described in the embodiment of the present invention are applicable to all other embodiments of the present application. It should be understood by those skilled in the art that the sequence of operations in these exemplary procedures may be changed, and some operations in these exemplary procedures may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0173] The following describes Figures 2 to 4 The exemplary procedures shown and described in or specific embodiments 1 to 4 of the above exemplary procedures performed by the UE, source MN, candidate (target) MN, source SN or candidate (target) SN in failure situations (not limited to the above situations 1 to 7 and situations A to C).

[0174] According to embodiments 1 to 4, the UE and the network node perform the following operations. For example, the UE may be as follows: Figure 1 The source MN (ie, S-MN) or target MN (ie, T-MN) or candidate (target) MN may be as follows: Figure 1 The source SN (ie, S-SN) or target SN (ie, T-SN) or candidate (target) SN may be as follows: Figure 1 SN 103 shown and described in.

[0175] Example 1

[0176] Embodiment 1 provides a solution for UE to store or report failure related information in a failure situation (not limited to the above-mentioned situations 1 to 7 and situations A to C). In embodiment 1, for the failure situation, in order to enable the network node to understand why the CHO including the target MCG and candidate SCG for the CPC / CPA procedure (i.e., the CHO with candidate SCG procedure) was not successfully executed, or to help the network node know whether or how to modify the configuration of this procedure (e.g., optimize the CHO execution condition, the CPAC execution condition, the CHO candidate PCell list or the CPAC candidate PSCell list), the UE may store or report the failure related information (e.g., as described above in Figure 2 Failure related information #1 described in the embodiment of FIG. 5 ). For example, the UE may store or report at least one of the following failure related information:

[0177] (1) Cell information of the source PCell. For example, in Embodiment 1, the cell information may include a physical cell identifier (PCI), carrier frequency information (e.g., an absolute radio frequency channel number (ARFCN)), and / or cell global identifier information (CGI-info) (e.g., a public land mobile network identifier (PLMN-Identity), a cell identifier, and a Tracking Area Code);

[0178] (2) Cell information of the failed PCell;

[0179] (3) When a failure occurs in scenario 2 “CHO with intra-SN CPC” or scenario 3 “CHO with inter-SN CPC” as described above, the cell information of the source PSCell may be stored or reported;

[0180] (4) Cell information of the failed PSCell;

[0181] (5) the type of the first satisfied or triggered execution condition (or conditional event), if any, e.g., whether the first satisfied or triggered execution condition (or conditional event) is a CHO execution condition (or CHO conditional event) or a CPAC execution condition (or CPAC conditional event);

[0182] (6) the type of the second satisfied or triggered execution condition (or conditional event), if any, e.g., whether the second satisfied or triggered execution condition (or conditional event) is a CPAC execution condition (or CPAC conditional event) or a CHO execution condition (or CHO conditional event);

[0183] (7) Information indicating whether one or both CPAC execution conditions (or CPAC condition events) of the CPAC candidate PSCell are satisfied or triggered. For example, the information may indicate if one or more CHO execution conditions (or CHO condition events) of the CHO candidate PCell are satisfied or triggered first. In addition, in some embodiments:

[0184] - If both the CHO execution condition and the CPAC execution condition are met, the UE further stores or reports information indicating whether the candidate PSCell meeting the CPAC execution condition is associated with the candidate PCell meeting the CHO execution condition. For example, the information may be an explicit indication or may be explicitly indicated by cell information of the PCell and the PSCell.

[0185] - If both the CHO execution condition and the CPAC execution condition are met, the UE further stores or reports information indicating whether the leaving condition of the candidate PCell that meets the CHO execution condition is met (e.g., when one or both CPAC execution conditions of the CPAC candidate PSCell are met or triggered);

[0186] -If both the CHO execution condition and the CPAC execution condition are met, the UE further stores or reports the duration between the two met or triggered execution conditions or condition events, for example, the time elapsed from the time one or two CHO execution conditions of the CHO candidate PCell are met or triggered until the time one or two CPAC execution conditions of the CPAC candidate PSCell are met or triggered (for the case if the CHO execution condition is associated with the CPAC execution condition, or if the candidate PSCell that meets the CPAC execution condition is associated with the candidate PCell that meets the CHO execution condition).

[0187] (8) Information indicating whether one or two CHO execution conditions (or CHO condition events) of the CHO candidate PCell are satisfied or triggered. For example, if one or two CPAC execution conditions (or CPAC condition events) of the CPAC candidate PSCell are first satisfied or triggered, then the information may be an indication. In addition, in some embodiments:

[0188] - If both the CHO execution condition and the CPAC execution condition are met, the UE further stores or reports information indicating whether the candidate PCell meeting the CHO execution condition is associated with the candidate PSCell meeting the CPAC execution condition. For example, the information may be an explicit indication or may be explicitly indicated by cell information of the PCell and the PSCell.

[0189] - If both the CHO execution condition and the CPAC execution condition are met, the UE further stores or reports information indicating whether the leaving condition of the candidate PSCell that meets the CPAC execution condition is met (e.g., when one or both CHO execution conditions of the CHO candidate PCell are met or triggered);

[0190] -If both the CHO execution condition and the CPAC execution condition are met, the UE further stores or reports the duration between the two met or triggered execution conditions or condition events, for example, the time elapsed from the time one or two CPAC execution conditions of the CPAC candidate PSCell are met or triggered until the time one or two CHO execution conditions of the CHO candidate PCell are met or triggered (for the case if the CHO execution condition is associated with the CPAC execution condition, or if the candidate PCell that meets the CHO execution condition is associated with the candidate PSCell that meets the CPAC execution condition).

[0191] In embodiment 1, at least one of the above failure related information may be reported by the UE via an MCG failure information message or an SCG failure information message or an RLF report.

[0192] Example 2

[0193] Embodiment 2 provides a solution for how a network node performs MRO analysis on a CHO including a target MCG and a candidate SCG for a CPC / CPA program (ie, a CHO with a candidate SCG program). Specifically, embodiment 2 includes the following specific embodiments 2-1, 2-2, and 2-3 under different circumstances.

[0194] Example 2-1

[0195] In embodiment 2-1, for a CHO including a target MCG and a candidate SCG for a CPC procedure, when an MCG failure or RLF or CHO execution failure occurs, the UE may send failure related information to the S-SN, for example, via an MCG failure information message. Detailed failure related information or information included in the MCG failure information message may refer to embodiment 1 (for example, as described above in Figure 2 The S-SN may transmit the failure related information to the S-MN.

[0196] In embodiment 2-1, for a CHO including a target MCG and a candidate SCG for a CPA procedure, when an MCG failure or an RLF or a CHO execution failure occurs, the UE may, for example, send failure-related information to a receiving node (which is a third-party node different from the S-MN) via an RLF report. For detailed failure-related information or information included in the RLF report, reference may be made to embodiment 1 (for example, as described above in Figure 2(See the failure-related information #1 described in the embodiment of FIG. 1 ). The receiving node may transmit the failure-related information to the S-MN. Alternatively, the receiving node may transmit the failure-related information to the S-SN. Alternatively, the receiving node may transmit the failure-related information to at least one candidate (target) MN. Alternatively, the receiving node may transmit the failure-related information to at least one candidate (target) SN.

[0197] In embodiment 2-1, when a failure occurs, or when the S-MN receives information related to the failure, the S-MN may select a PCell for failure recovery (for example, the S-MN may select a PCell for fast MCG failure recovery), and the S-MN may perform root cause analysis. For example, the S-MN may perform the following operations:

[0198] (1) If the selected PCell is not included in the CHO candidate PCells suggested, notified, or provided by the S-MN to the candidate (target) MN that manages the CHO candidate PCells, the S-MN knows that the CHO candidate PCell suggested, notified, or provided by the S-MN is not suitable, then the S-MN may modify the CHO candidate PCell list for MRO purposes.

[0199] (2) If the selected PCell is included in the CHO candidate PCells suggested, notified, or provided by the S-MN to the candidate (target) MN, but is not included in the CHO candidate PCells selected or prepared by the candidate (target) MN, the S-MN may understand that an incorrect CHO candidate PCell was selected or prepared by the candidate (target) MN. If so, the S-MN may notify the candidate (target) MN, for example, via a message or indication, that an incorrect CHO candidate PCell was selected or prepared. The candidate (target) MN may modify the CHO candidate PCell selected or prepared for CHO including the target MCG and candidate SCG for the CPC procedure.

[0200] (3) If the selected PCell is included in the CHO candidate PCells selected or prepared by the candidate (target) MN, the S-MN may know that it has set inappropriate CHO execution conditions for the CHO candidate PCells configured for the UE or for the CHO candidate PCells selected or prepared by the candidate (target) MN. The S-MN may optimize the CHO execution conditions for these CHO candidate PCells.

[0201] Example 2-2

[0202] In embodiment 2-2, for a CHO including a target MCG and a candidate SCG for CPC / CPA procedures, when an SCG failure or RLF or CPAC execution failure occurs, the UE may send failure-related information to the source MN (S-MN) via an SCG failure information message, for example. Detailed failure-related information or information included in the SCG failure information message may refer to embodiment 1 (for example, as described above in Figure 2 Failure related information #1) described in the embodiment.

[0203] Example 2-2-1

[0204] Example 2-2-1 assumes that one or more candidate (target) MNs propose, notify, or provide CPAC candidate PSCells, and that the CPAC execution conditions for the CPAC candidate PSCells are determined or generated by the one or more candidate (target) MNs. A candidate (target) SN is a node that manages one or more CPAC candidate PSCells. A candidate (target) MN is a node that manages one or more CHO candidate PCells.

[0205] In Example 2-2-1, when a failure occurs, or when the S-MN receives information related to the failure, the S-MN may select a PSCell, for example, the S-MN may select a suitable PSCell for SCG reconfiguration; if the S-MN selects a PSCell, then the S-MN may send the cell information of the selected PSCell to one or more candidate (target) MNs; or, a candidate (target) MN may select a PSCell for recovering the failure, for example, the candidate (target) MN may select a suitable PSCell for SCG reconfiguration; if the candidate (target) MN selects a PSCell, then the candidate (target) MN may send the cell information of the selected PSCell to the S-MN, and the S-MN may send the PSCell information to the UE for SCG reconfiguration.

[0206] In embodiment 2-2-1, the S-MN may perform an initial analysis and / or the S-MN may send failure-related information to one or more candidate (target) MNs, for example, via existing X2 / Xn messages or newly introduced X2 / Xn messages. One or more candidate (target) MNs may send failure-related information to one or more candidate (target) SNs, for example, via existing X2 / Xn messages or newly introduced X2 / Xn messages. In embodiment 2-2-1, the S-MN may send failure-related information to the source SN, for example, via existing X2 / Xn messages or newly introduced X2 / Xn messages.

[0207] In embodiment 2-2-1, any one of the one or more candidate (target) MNs may perform a root cause analysis. For example, the candidate (target) MN may perform the following operations:

[0208] (1) If the selected PSCell is not included in the CPAC candidate PSCells suggested, notified, or provided by the candidate (target) MN to one or more candidate (target) SNs, the candidate (target) MN knows that the CPAC candidate PSCell suggested, notified, or provided by itself is unsuitable. The candidate (target) MN may then modify the CPAC candidate PSCell list for MRO purposes.

[0209] (2) If the selected PSCell is included in the CPAC candidate PSCells suggested, notified, or provided by the candidate (target) MN to one or more candidate (target) SNs, but is not included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, then the candidate (target) MN knows that the CPAC candidate PSCell list is incorrectly selected or prepared by the candidate (target) SN. If so, the candidate (target) MN may, for example, notify one or more candidate (target) SNs, respectively, via a message or indication, that the CPAC candidate PSCell list is incorrectly selected or prepared. Then, the one or more candidate (target) SNs may respectively modify the CPAC candidate PSCells selected or prepared for the CHO including the target MCG and candidate SCG for the CPC / CPA procedure.

[0210] (3) If the selected PSCell is included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, the candidate (target) MN knows that it has set inappropriate CPAC execution conditions for the CPAC candidate PSCells configured for the UE (or for the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs). The candidate (target) MN can then optimize the CPAC execution conditions for these CPAC candidate PSCells.

[0211] Example 2-2-2

[0212] Example 2-2-2 assumes that the S-MN recommends, notifies, or provides a CPAC candidate PSCell, and the CPAC execution conditions of the CPAC candidate PSCell are determined or generated by the candidate (target) MN.

[0213] In Example 2-2-2, when a failure occurs, or when the S-MN receives information related to the failure, the S-MN may select a PSCell for recovering the failure (for example, the S-MN may select a suitable PSCell for SCG reconfiguration); if the S-MN selects a PSCell, then the S-MN may send the cell information of the selected PSCell to one or more candidate (target) MNs; or, the candidate (target) MN may select a PSCell for recovering the failure (for example, the candidate (target) MN may select a suitable PSCell for SCG reconfiguration); if the candidate (target) MN selects a PSCell, then the candidate (target) MN may send the cell information of the selected PSCell to the S-MN, and the S-MN may send the PSCell information to the UE for SCG reconfiguration.

[0214] In embodiment 2-2-2, the S-MN may send failure-related information to one or more candidate (target) MNs, for example, via existing X2 / Xn messages or newly introduced X2 / Xn messages. One or more candidate (target) MNs may send failure-related information to one or more candidate (target) SNs, for example, via existing X2 / Xn messages or newly introduced X2 / Xn messages.

[0215] In embodiment 2-2-2, the S-MN may send failure-related information to the source SN via, for example, existing X2 / Xn messages or newly introduced X2 / Xn messages.

[0216] In Example 2-2-2, the S-MN may perform a root cause analysis. For example, the S-MN may perform the following operations:

[0217] (1) If the selected PSCell is not included in the CPAC candidate PSCells proposed or provided by the S-MN, the S-MN knows that the CPAC candidate PSCell proposed or provided by the S-MN is not suitable. The S-MN can then modify the CPAC candidate PSCell list for MRO purposes.

[0218] (2) If the selected PSCell is included in the CPAC candidate PSCells suggested or provided by the S-MN, but is not included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, then the S-MN knows that one or more incorrect CPAC candidate PSCells are selected or prepared by one or more candidate (target) SNs. If so, the S-MN may directly (e.g., via a message or indication) or indirectly via one or more candidate (target) MNs notify one or more candidate (target) SNs that one or more incorrect CPAC candidate PSCells are selected or prepared (i.e., the S-MN may instruct one or more candidate (target) MNs to notify one or more candidate (target) SNs that one or more incorrect CPAC candidate PSCells are selected or prepared (e.g., via a message or indication)); and optionally, the S-MN may notify one or more candidate (target) MNs of the ID information of one or more candidate (target) SNs. Then, any one of the one or more candidate (target) MNs may notify one or more candidate (target) SNs that one or more incorrect CPAC candidate PSCells are selected or prepared (e.g., via a message or indication, based on the ID information of the one or more candidate (target) SNs, respectively). The one or more candidate (target) SNs may respectively modify the CPAC candidate PSCells selected or prepared for the CHO including the target MCG and candidate SCG for the CPC / CPA procedure.

[0219] (3) If the selected PSCell is included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, the S-MN knows that one or more candidate (target) MNs have set inappropriate CPAC execution conditions for the CPAC candidate PSCells configured for the UE (or for the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs). The S-MN may separately notify one or more candidate (target) MNs that the CPAC execution conditions are inappropriately set (e.g., via a message or indication). Then, the candidate (target) MNs may respectively optimize the CPAC execution conditions for these CPAC candidate PSCells.

[0220] Example 2-2-3

[0221] Example 2-2-3 assumes that the S-MN recommends, notifies, or provides a CPAC candidate PSCell, and the CPAC execution conditions of the CPAC candidate PSCell are determined or generated by the S-MN.

[0222] In Example 2-2-3, when a failure occurs, or when the S-MN receives information related to the failure, the S-MN may select a PSCell for recovering the failure (for example, the S-MN may select a suitable PSCell for SCG reconfiguration); if the S-MN selects a PSCell, then the S-MN may send the cell information of the selected PSCell to one or more candidate (target) MNs; or, the candidate (target) MN may select a PSCell for recovering the failure (for example, the candidate (target) MN may select a suitable PSCell for SCG reconfiguration); if the candidate (target) MN selects a PSCell, then the candidate (target) MN may send the cell information of the selected PSCell to the S-MN, and the S-MN may send the PSCell information to the UE for SCG reconfiguration.

[0223] In embodiment 2-2-3, the S-MN may send failure-related information to one or more candidate (target) MNs, for example, via existing X2 / Xn messages or newly introduced X2 / Xn messages. One or more candidate (target) MNs may send failure-related information to one or more candidate (target) SNs, for example, via existing X2 / Xn messages or newly introduced X2 / Xn messages. In embodiment 2-2-3, the S-MN may send failure-related information to the source SN, for example, via existing X2 / Xn messages or newly introduced X2 / Xn messages.

[0224] In Example 2-2-3, the S-MN may perform a root cause analysis. For example, the S-MN may perform the following operations:

[0225] (1) If the selected PSCell is not included in the CPAC candidate PSCells suggested or provided by the S-MN, the S-MN knows that the CPAC candidate PSCell suggested or provided by the S-MN is not suitable, and the S-MN may modify the CPAC candidate PSCell list for MRO purposes.

[0226] (2) If the selected PSCell is included in the CPAC candidate PSCells suggested or provided by the S-MN, but is not included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, the S-MN knows that the CPAC candidate PSCell list is incorrectly selected or prepared by one or more candidate (target) SNs. If so, the S-MN may directly (e.g., via a message or indication) or indirectly via one or more candidate (target) MNs notify one or more candidate (target) SNs that the CPAC candidate PSCell list is incorrectly selected or prepared (i.e., the S-MN may respectively instruct one or more candidate (target) MNs to notify one or more candidate (target) SNs that the CPAC candidate PSCell list is incorrectly selected or prepared (e.g., via a message or indication)); and optionally, the S-MN may notify one or more candidate (target) MNs of the ID information of one or more candidate (target) SNs. Then, any one of the one or more candidate (target) MNs may notify the one or more candidate (target) SNs that the CPAC candidate PSCell list is incorrectly selected or prepared (e.g., via a message or indication, based on the ID information of the one or more candidate (target) SNs, respectively). The one or more candidate (target) SNs may respectively modify the CPAC candidate PSCells selected or prepared for the CHO including the target MCG and candidate SCG for the CPC / CPA procedure.

[0227] (3) If a suitable PSCell is included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, the S-MN knows that it has set inappropriate CPAC execution conditions for the CPAC candidate PSCells configured for the UE (or for the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs). The S-MN can then optimize the CPAC execution conditions for these CPAC candidate PSCells.

[0228] Example 2-2-4

[0229] Example 2-2-4 assumes that one or more candidate (target) MNs recommend, notify, or provide CPAC candidate PSCells, and the CPAC execution conditions of the CPAC candidate PSCells are determined or generated by the S-MN.

[0230] In Example 2-2-4, when a failure occurs, or when the S-MN receives information related to the failure, the S-MN may select a PSCell (for example, the S-MN may select a suitable PSCell for SCG reconfiguration); if the S-MN selects a PSCell, then the S-MN may send the cell information of the selected PSCell to one or more candidate (target) MNs; or, the candidate (target) MN may select a PSCell for recovering the failure (for example, the candidate (target) MN may select a suitable PSCell for SCG reconfiguration); if the candidate (target) MN selects a PSCell, then the candidate (target) MN may send the cell information of the selected PSCell to the S-MN, and the S-MN may send the PSCell information to the UE for SCG reconfiguration.

[0231] In embodiment 2-2-4, the S-MN may perform an initial analysis and / or the S-MN may send failure-related information to one or more candidate (target) MNs, for example, via existing X2 / Xn messages or newly introduced X2 / Xn messages. The one or more candidate (target) MNs may send failure-related information to one or more candidate (target) SNs, for example, via existing X2 / Xn messages or newly introduced X2 / Xn messages. In embodiment 2-2-4, the S-MN may send failure-related information to the source SN, for example, via existing X2 / Xn messages or newly introduced X2 / Xn messages.

[0232] In embodiment 2-2-4, any one of the one or more candidate (target) MNs may perform root cause analysis. For example, the candidate (target) MN may perform the following operations:

[0233] (1) If the selected PSCell is not included in the CPAC candidate PSCells suggested, notified, or provided by the candidate (target) MN to one or more candidate (target) SNs, the candidate (target) MN knows that the CPAC candidate PSCell suggested, notified, or provided by the candidate (target) MN is unsuitable. The candidate (target) MN may then modify the CPAC candidate PSCell list for MRO purposes.

[0234] (2) If the selected PSCell is included in the CPAC candidate PSCells suggested, notified, or provided by the candidate (target) MN to one or more candidate (target) SNs, but is not included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, then the candidate (target) MN knows that one or more incorrect CPAC candidate PSCells are selected or prepared by the candidate (target) SN. If so, the candidate (target) MN may, for example, notify one or more candidate (target) SNs via a message or indication that one or more incorrect CPAC candidate PSCells are selected or prepared. Then, the one or more candidate (target) SNs may respectively modify the CPAC candidate PSCells selected or prepared for the CHO with the candidate SCG procedure;

[0235] (3) If the selected PSCell is included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, the candidate (target) MN knows that the S-MN has set inappropriate CPAC execution conditions for the CPAC candidate PSCells configured for the UE (or for the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs). The candidate (target) MN may notify the S-MN, for example, via a message or indication, that the CPAC execution conditions are inappropriately set. The S-MN may then optimize the CPAC execution conditions for these CPAC candidate PSCells.

[0236] Example 2-3

[0237] In embodiments 2-3, for a CHO including a target MCG and a candidate SCG for CPC / CPA procedures, when both an MCG failure and an SCG failure occur, the UE may send failure-related information to a network node (e.g., a node different from the source MN or source SN) via an RLF report. Detailed failure-related information or information included in the RLF report may refer to embodiment 1 (e.g., as described above in Figure 2 Failure related information #1) described in the embodiment.

[0238] In Embodiment 2-3, the network node that receives the failure-related information or RLF report may forward the failure-related information or RLF report to the S-MN. The S-MN may forward the failure-related information or RLF report to the S-SN or one or more candidate (target) MNs. The one or more candidate (target) MNs may transmit the failure-related information or RLF report to the one or more candidate (target) SNs.

[0239] Example 3

[0240] Embodiment 3 provides a solution for MRO analysis in a CHO procedure. In a CHO procedure, when an RLF occurs before a CHO execution condition is met, or when a CHO execution failure occurs, the receiving node (i.e., the node that receives the RLF report from the UE) sends the RLF report to the source node via a Failure Indication message. In a CHO procedure, when an RLF occurs shortly after a successful CHO execution from a source cell to a target cell, the receiving node (the node that receives the RLF report from the UE) sends the RLF report to the target node via a Failure Indication message, and the target node may then send the RLF report to the source node via a Handover (HO) Report message.

[0241] In embodiment 3, when a failure occurs, the UE may select a cell for recovering the failure (for example, the UE may select a cell for CHO recovery), and the cell may be presented by the choCellId information element (IE) in the 3GPP standard document TS38.331, which is used to indicate the candidate (target) cell for conditional switching contained in the condRRCReconfigIE selected by the UE for CHO-based recovery when timer T311 is running, or if the cell selected for the failed recovery / reestablishment attempt is not a candidate (target) cell for conditional reconfiguration, then the cell may be presented by the reestablishmentCellId IE in the 3GPP standard document TS38.331, which is used to indicate the cell for the failed recovery / reestablishment attempt after the failure. The cell information of the cell used to recover the failure may be included in the RLF report. In embodiment 3, the source node may perform root cause analysis, for example, the source node may perform the following operations:

[0242] (1) If the cell used for recovery failure is not included in the CHO candidate PCells suggested or provided by the source node, the source node knows that the CHO candidate PCell suggested or provided by the source node is not suitable. Then, the source node can modify the CHO candidate PCell list for MRO purposes.

[0243] (2) If the cell used for recovery failure is included in the CHO candidate PCells suggested or provided by the source node but is not included in the CHO candidate PCells selected or prepared by one or more candidate (target) nodes, the source node knows that the CHO candidate PCell list was incorrectly selected or prepared by one or more candidate (target) nodes. If so, the source node notifies the one or more candidate (target) nodes, for example, via a message or indication, that one or more incorrect CHO candidate PCells were selected or prepared. The one or more candidate (target) nodes may then modify the selected or prepared CHO candidate PCells.

[0244] (3) If the cell used for recovery failure is included in the CHO candidate PCells selected or prepared by one or more candidate (target) nodes, the source node knows that it has set inappropriate CHO execution conditions for the candidate PCells configured for the UE (or the CHO candidate PCells selected or prepared by the candidate (target) node). The source node can then optimize the CHO execution conditions for these CHO candidate PCells.

[0245] Example 4

[0246] Embodiment 4 provides a solution for MRO analysis in a CPA procedure, a CPC procedure, or a CPAC procedure. In a CPA procedure, when CPA execution fails, or when an SCG failure occurs shortly after a successful CPA execution, the UE may send an SCG Failure Information message to the MN. In a CPC procedure, when an SCG failure occurs before CPC execution conditions are met, when CPC execution fails, or when an SCG failure occurs shortly after a successful CPC execution from a source PSCell to a target PSCell, the UE may send an SCG Failure Information message to the MN.

[0247] In embodiment 4, for a CPA procedure or a CPC procedure initiated by a MN, when a failure occurs, or when the MN receives failure-related information in an SCG failure information message, the MN may select a PSCell for recovering the failure. For example, the MN may select a suitable PSCell for SCG reconfiguration. The MN may perform a root cause analysis. For example, the MN may perform the following operations:

[0248] (1) If the selected PSCell is not included in the CPAC candidate PSCells suggested or notified by the MN to one or more candidate (target) SNs, the MN knows that the CPAC candidate PSCell suggested or notified by the MN is not suitable, and the MN may modify the CPAC candidate PSCell list;

[0249] (2) If the selected PSCell is included in the CPAC candidate PSCells suggested or notified by the MN, but is not included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, the MN knows that the CPAC candidate PSCell list is incorrectly selected or prepared by one or more candidate (target) SNs. If so, the MN may notify the one or more candidate (target) SNs, for example, via a message or indication, that the CPAC candidate PSCell list is incorrectly selected or prepared, and the one or more candidate (target) SNs may modify the selected or prepared CPAC candidate PSCells.

[0250] (3) If the selected PSCell is included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, the MN knows that it has set inappropriate CPAC execution conditions for the candidate PSCells configured for the UE (or for the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs), and the MN can optimize the CPAC execution conditions for these candidate PSCells;

[0251] In embodiment 4, for the CPC procedure initiated by the SN, in an example, when a failure occurs, or when the MN receives failure-related information in an SCG failure information message, the MN may select a PSCell for recovering the failure (for example, the MN may select a suitable PSCell for SCG reconfiguration), and then, the MN may send cell information of the selected PSCell to the source SN; in another example, when a failure occurs, or when the source SN receives failure-related information, the source SN may select a PSCell for recovering the failure (for example, the source SN may select a suitable PSCell for SCG reconfiguration), and then, the source SN may send cell information of the selected PSCell to the MN. In embodiment 4, the MN may perform an initial analysis and transmit the SCG failure information to the S-SN, and the S-SN may perform a root cause analysis, for example, the S-SN may perform the following operations:

[0252] (1) If the selected PSCell is not included in the CPAC candidate PSCells suggested or provided by the S-SN, the S-SN knows that the CPAC candidate PSCell suggested or provided by the S-SN is not suitable. Then, the S-SN may modify the CPAC candidate PSCell list.

[0253] (2) If the selected PSCell is included in the CPAC candidate PSCells suggested or provided by the S-SN, but is not included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, then the S-SN knows that the CPAC candidate PSCell list is incorrectly selected or prepared by one or more candidate (target) SNs. If so, the S-SN may directly, for example, via a message or indication, or indirectly via the MN, notify the one or more candidate (target) SNs that the CPAC candidate PSCell list is incorrectly selected or prepared (i.e., the S-SN may instruct the MN to notify the one or more candidate (target) SNs that the CPAC candidate PSCell list is incorrectly selected or prepared (e.g., via a message or indication)), and optionally, the S-SN may notify the MN of the ID information of the one or more candidate (target) SNs. Then, the MN may notify the one or more candidate (target) SNs that the CPAC candidate PSCell list is incorrectly selected or prepared (e.g., via a message or indication, correspondingly based on the ID information of the one or more candidate (target) SNs). One or more candidate (target) SNs may modify the selected or prepared CPAC candidate PSCell, respectively.

[0254] (3) If the selected PSCell is included in the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs, the S-SN knows that it has set inappropriate CPAC execution conditions for the candidate PSCells configured for the UE (or for the CPAC candidate PSCells selected or prepared by one or more candidate (target) SNs), and the S-SN can optimize the CPAC execution conditions for these candidate PSCells.

[0255] Figure 5 1 is a block diagram illustrating an exemplary apparatus 500 according to some embodiments of the present disclosure. Figure 5 As shown in , apparatus 500 may include at least one processor 506 and at least one transceiver 502 coupled to the processor 506 .

[0256] Although in this figure, elements such as at least one transceiver 502 and processor 506 are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present application, transceiver 502 may be divided into two devices, such as receive circuitry and transmit circuitry. In some embodiments of the present application, apparatus 500 may further include an input device, memory, and / or other components.

[0257] In some embodiments of the present application, the device 500 may be a UE, a source MN, a candidate MN, a source SN, or a candidate SN. The transceiver 502 and the processor 506 may interact with each other to execute the above, for example, Figures 1 to 4The operations regarding UE, candidate MN, source MN, candidate SN or source SN described in any of .

[0258] In some embodiments of the present application, the device 500 may further include at least one non-transitory computer-readable medium. For example, in some embodiments of the present disclosure, the non-transitory computer-readable medium may store thereon computer-executable instructions to enable the processor 506 to implement the method described above with respect to the UE. For example, when the computer-executable instructions are executed, the processor 506 interacts with the transceiver 502 to perform Figures 1 to 4 The operations described in regarding UE, candidate MN, source MN, candidate SN or source SN.

[0259] Those skilled in the art will appreciate that the operations or steps of the methods described in conjunction with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Additionally, in some aspects, the operations or steps of the methods may reside as one or any combination or set of code and / or instructions on a non-transitory computer-readable medium that can be incorporated into a computer program product.

[0260] Although the present disclosure has been described using specific embodiments thereof, it is apparent that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or replaced in other embodiments. Furthermore, not all elements of each figure are necessary for the operation of the disclosed embodiments. For example, it will enable one of ordinary skill in the art to make and use the teachings of the present disclosure by simply adopting the elements of the independent claims. Therefore, the embodiments of the present disclosure as set forth herein are intended to be illustrative, not restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0261] In this document, the term "includes, including" or any other variation thereof is intended to encompass non-exclusive inclusion, such that the process, method, article, or device comprising a list of elements not only includes those elements but also may include other elements that are not explicitly listed or inherent to this process, method, article, or device. An element beginning with "a, an" or the like does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element without further constraints. Moreover, the term "another" is defined as at least a second or more. As used herein, the term "having" and the like are defined as "including." For example, the expression "A and / or B" or "at least one of A and B" may include any one and all combinations of the words enumerated together with the expression. For example, the expression "A and / or B" or "at least one of A and B" may include A, B, or both A and B. The phrases "first," "second," or the like are only used to clearly illustrate embodiments of the present application and are not intended to limit the substantive content of the present application.

Claims

1. A network node, comprising: transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the network node to: When a failure occurs in one of the following, information for recovering the failed cell is obtained: Conditional switching CHO program, Conditional primary and secondary cell group cell PSCell add or change CPAC procedure, and CHO including the target primary cell group MCG and candidate secondary cell group SCG for the conditional PSCell change / conditional PSCell add CPC / CPA procedures; and An analysis is performed on the failure.

2. The network node according to claim 1 , wherein the network node is a source master node (MN), and the processor is configured to cause the source MN to perform at least one of the following: Modify the CPAC candidate PSCell list; transmitting first information to at least one candidate SN to indicate that one or more CPAC candidate PSCells are incorrectly selected; instructing one or more candidate MNs to transmit the first information to the at least one candidate SN; Optimizing a set of CPAC execution conditions; or Second information is transmitted to the one or more candidate MNs to indicate that the set of CPAC execution conditions is improperly configured.

3. The network node according to claim 1 , wherein the network node is a source master node (MN), and the processor is configured to cause the source MN to perform at least one of the following: Modify the CHO candidate PCell list; transmitting third information to at least one candidate MN to indicate that one or more CHO candidate PCells are erroneously selected; or Optimize a set of CHO execution conditions.

4. The network node according to any one of claims 2 and 3, wherein the processor is configured to cause the source MN to: determining the information of the cell; transmitting the information of the cell; or Receive the information of the cell.

5. The network node according to any one of claims 2 and 3, wherein the processor is configured to cause the source MN to: transmitting failure-related information associated with the failure; or Receive the failure-related information.

6. The network node according to claim 1 , wherein the network node is a candidate master node (MN), and the processor is configured to cause the candidate MN to perform at least one of the following: Modify the CPAC candidate PSCell list; transmitting fourth information to at least one candidate SN to indicate that one or more CPAC candidate PSCells are incorrectly selected; Optimizing a set of CPAC execution conditions; or Fifth information is transmitted to the source MN to indicate that the set of CPAC execution conditions is improperly configured.

7. The network node according to claim 1 , wherein the network node is a candidate master node (MN), and the processor is configured to cause the candidate MN to perform at least one of the following: receiving sixth information from the source MN indicating that at least one CHO candidate PCell is erroneously selected; or One or more CHO candidate PCells selected by the candidate MN are modified.

8. The network node according to any one of claims 6 and 7, wherein the processor is configured to cause the candidate MN to: determining the information of the cell; transmitting the information of the cell; or Receive the information of the cell.

9. The network node according to any one of claims 6 and 7, wherein the processor is configured to cause the candidate MN to receive failure-related information associated with the failure.

10. The network node according to claim 1, wherein the network node is a source slave node (SN), the processor being configured to cause the source SN to perform at least one of the following: Modify the CPAC candidate PSCell list; transmitting seventh information to at least one candidate SN to indicate that one or more CPAC candidate PSCells are incorrectly selected; instructing the source MN to transmit the seventh information to the at least one candidate SN; or Optimize a set of CPAC execution conditions.

11. The network node according to claim 10, wherein the processor is configured to cause the source SN to: determining the information of the cell; transmitting the information of the cell; or Receive the information of the cell.

12. The network node according to claim 10, wherein the processor is configured to cause the source SN to receive failure-related information associated with the failure.

13. The network node according to any one of claims 5, 9 and 12, wherein the failure-related information comprises at least one of the following: The first type of execution condition is satisfied; The second type of execution condition is met; Information indicating whether the CPAC execution conditions of the CPAC candidate PSCell are met; Information indicating whether the CHO execution condition of the CHO candidate PCell is satisfied; Information indicating whether a candidate PSCell that meets the CPAC execution condition is associated with a candidate PCell that meets the CHO execution condition; Information indicating whether a leaving condition of the candidate PCell meeting the CHO execution condition is satisfied; Information indicating whether a leaving condition of the candidate PSCell meeting the CPAC execution condition is met; the time elapsed from the time the CHO execution condition is satisfied until the time the CPAC execution condition is satisfied; or The time elapsed from when the CPAC execution condition is satisfied until when the CHO execution condition is satisfied.

14. A candidate secondary node SN, comprising: transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the candidate SN to perform at least one of the following: Receiving information indicating that one or more conditional primary and secondary cell group cells (PSCells) are added or modified CPAC candidate PSCells are incorrectly selected, wherein the information is received from a source master node MN, a candidate MN, or a source SN; or Modify the one or more CPAC candidate PSCells.

15. A user equipment (UE), comprising: transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the UE to: storing failure related information associated with a failure, wherein the failure occurs in a conditional handover CHO including a target primary cell group MCG and a candidate secondary cell group SCG for a conditional primary and secondary cell group PSCell change / conditional PSCell addition CPC / CPA procedure; and Transmitting information related to the failure.

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