Method and apparatus for CHO process related to candidate scg

Abstract

A user equipment (UE) includes a transceiver and a processor coupled to the transceiver, and the processor is configured to receive, via the transceiver, from a source master node (MN), at least one of a configuration set of at least one candidate primary cell (PCell), a configuration set of at least one candidate PSCell, a conditional handover (CHO) execution condition set of the at least one candidate PCell, a configuration set of the at least one candidate PSCell, a configuration set of the at least one candidate PSCell, and a configuration set of the at least one candidate PSCell. Or a conditional primary secondary cell group cell (PSCell) addition or change (CPAC) execution condition set of the at least one candidate PSCell; and in response to at least one of: generating a source secondary cell group (SCG) failure, generating a source primary cell group (MCG) failure, not fulfilling the CHO execution condition set, not fulfilling the CPAC execution condition set, or generating a failure during CHO execution, performing one of: initiating a failure recovery procedure; starting CHO execution; and continuing the CHO execution.

Description

Technical Field

[0001] Embodiments of the present application generally relate to methods and apparatus for a conditional handover (CHO) procedure with respect to a candidate secondary cell group (SCG). Background Art

[0002] In a multi-radio dual connectivity (MR-DC) scenario, a UE with multiple transceivers may be configured to utilize resources provided by two different nodes connected via a non-ideal backhaul. One of the nodes may provide new radio (NR) access and the other may provide evolved universal mobile telecommunications system (UMTS) terrestrial radio access (UTRA) (E-UTRA) or NR access. One node may act as a master node (MN) and the other may act as a secondary node (SN). The MN and the SN are connected via a network interface (e.g., an Xn or X2 interface specified in the 3rd Generation Partnership Project (3GPP) standard document), and at least the MN is connected to a core network.

[0003] Currently, the conditional PSCell addition (CPA) process and the conditional PSCell change (CPC) process are supported. The CPAC process is a CPA process or a CPC process. According to the agreement of the 3GPP standard document, the CPAC process is defined as the PSCell addition or PSCell change performed by the UE when the execution conditions configured for CPAC are met or fulfilled. The UE starts to evaluate the CPAC execution conditions immediately after receiving the CPAC-related configuration information, and stops evaluating the CPAC execution conditions once the PSCell addition and / or change process is triggered or executed. The triggering or execution of the PSCell addition and / or change process means that when the CPAC execution conditions of the candidate PSCell are met or fulfilled, the UE determines the candidate PSCell as the target PSCell, and performs the PSCell addition or change process on the target PSCell, for example, the UE performs the RA process to the target PSCell.

[0004] CHO is defined as a handover performed by a user equipment (UE) when one or more handover or CHO execution conditions are met. The UE starts evaluating one or more CHO execution conditions immediately after 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 one or more CHO execution conditions are met or fulfilled. CHO execution means that when the CHO execution conditions of a candidate PCell are met or fulfilled, the UE decides the candidate PCell as the target PCell and performs a PCell change or handover process with respect to the target PCell, for example, the UE performs a RA process to the target PCell. Currently, details related to the CHO process with respect to a candidate SCG in an MR-DC scenario have not been discussed. Summary of the invention

[0005] Some embodiments of the present application provide a user equipment (UE). The UE includes a transceiver and a processor coupled to the transceiver; and the processor is configured to: receive at least one of the following items from a source master node (MN) via the transceiver: a first configuration set of at least one candidate primary cell (PCell), a second configuration set of at least one candidate primary secondary cell group cell (PSCell), a conditional handover (CHO) execution condition set of the at least one candidate PCell, or a conditional PSCell addition or change (CPAC) execution condition set of the at least one candidate PSCell; and in response to at least one of the following items: a source secondary cell group (SCG) failure occurs, a source master cell group (MCG) failure occurs, the CHO execution condition set is not fulfilled, the CPAC execution condition set is not fulfilled, or a failure occurs during CHO execution, perform one of the following items: start a failure recovery process; start CHO execution; and continue the CHO execution.

[0006] In some embodiments, the second configuration set is associated with the first configuration set; or the second configuration set is encapsulated in the first configuration set.

[0007] In some embodiments, the at least one candidate PSCell is associated with the at least one candidate PCell.

[0008] In some embodiments, in order to receive at least one of the first configuration set or the second configuration set, the processor of the UE is configured to: receive the first configuration set, wherein the second configuration set is encapsulated in the first configuration set; or receive the first configuration set and the second configuration set separately.

[0009] In some embodiments, the CPAC execution condition set is associated with the CHO execution condition set, or the CPAC execution condition set is encapsulated in the CHO execution condition set.

[0010] In some embodiments, in order to receive at least one of the CHO execution condition set or the CPAC execution condition set, the processor of the UE is configured to: receive the CHO execution condition set, wherein the CPAC execution condition set is encapsulated in the CHO execution condition set; or receive the CHO execution condition set and the CPAC execution condition set separately.

[0011] In some embodiments, in response to initiating the fault recovery process, the processor of the UE is configured to: perform a cell selection operation to select a cell; in response to the selected cell belonging to the at least one candidate PCell, determine the selected cell as a target PCell and perform a switching operation to the target PCell; or in response to the selected cell not belonging to the at least one candidate PCell, perform a radio resource control (RRC) reconstruction process.

[0012] In some embodiments, in response to selecting that the selected cell belongs to the at least one candidate PCell or in response to performing the switching operation to the target PCell or in response to successfully completing the switching operation to the target PCell, the processor of the UE is configured to perform at least one of the following: selecting a candidate PSCell associated with the target PCell and adding the selected candidate PSCell as a target PSCell; or evaluating one or more CPAC execution conditions within the CPAC execution condition set for at least one candidate PSCell associated with the target PCell.

[0013] In some embodiments, in response to evaluating the one or more CPAC execution conditions, the processor of the UE is configured to: in response to fulfilling the CPAC execution conditions of a candidate PSC within at least one candidate PSCell associated with the target PCell, add the candidate PSCell as the target PSCell; or in response to not fulfilling the one or more CPAC execution conditions, transmit at least one of the following items to a target master node (MN) that manages the target PCell via the transceiver: information indicating that the one or more CPAC execution conditions have not been fulfilled; or information related to at least one of the failure events.

[0014] In some embodiments, the at least one of the failure events includes: the occurrence of the source SCG failure; the occurrence of the source MCG failure; the failure to fulfill the CHO execution condition set; the failure to fulfill the CPAC execution condition set; or the occurrence of the failure during the CHO execution.

[0015] In some embodiments, the processor of the UE is configured to: concurrently evaluate the CHO execution condition set and the CPAC execution condition set; or first evaluate the CHO execution condition set, and in response to fulfilling the CHO execution conditions for the candidate PCell in the CHO execution condition set, evaluate the CPAC execution conditions in the CPAC execution condition set for the candidate PSCell associated with the candidate PCell whose CHO execution conditions are fulfilled.

[0016] In some embodiments, in response to concurrently evaluating the CHO execution condition set and the CPAC execution condition set and in response to the CPAC execution condition set of the at least one candidate PSCell being fulfilled before the CHO execution condition set of the at least one candidate PCell is fulfilled, the processor of the UE is configured to: continue CHO execution condition evaluation for at least one candidate PCell associated with the candidate PSCell whose CPAC execution condition is fulfilled within the at least one candidate PSCell until the source SCG failure occurs or until a first configured duration is reached.

[0017] In some embodiments, the first configured duration is configured by a target MN or a source MN.

[0018] In some embodiments, in response to concurrently evaluating the CHO execution condition and the CPAC execution condition and in response to the CHO execution condition set of the at least one candidate PCell being fulfilled before the CPAC execution condition set of the at least one candidate PSCell being fulfilled, the processor of the UE is configured to: continue CPAC execution condition evaluation for at least one candidate PSCell associated with the candidate PCell whose CHO execution condition within the at least one candidate PCell is fulfilled until the failure occurs during the CHO execution or until a second configured duration is reached.

[0019] In some embodiments, the second configured duration is configured by a target MN or a target secondary node (SN).

[0020] In some embodiments, the processor of the UE is configured to receive at least one of the first configured duration or the second configured duration from a source MN via the transceiver.

[0021] Some embodiments of the present application also provide a target master node (MN). The target MN includes a transceiver and a processor coupled to the transceiver; and the processor is configured to receive information related to at least one of the failure events from a user equipment (UE) via the transceiver, wherein the at least one of the failure events includes: a source secondary cell group (SCG) failure occurs; a source master cell group (MCG) failure occurs; a conditional handover (CHO) execution condition set of at least one candidate primary cell (PCell) is not fulfilled; a conditional primary secondary cell group cell (PSCell) addition or change (CPAC) execution condition set of at least one candidate PCell is not fulfilled; or a failure occurs during CHO execution.

[0022] In some embodiments, the processor of the target MN is configured to transmit the information related to the at least one of the failure events to the source MN via the transceiver.

[0023] In some embodiments, the processor of the target MN is configured to: generate a first configured duration, wherein the first configured duration is used by the UE during the UE's continued CHO execution condition evaluation, wherein the continued CHO execution condition evaluation is for one or more candidate PCells associated with a candidate PSCell in which a CPAC execution condition is fulfilled within at least one candidate PCell configured for the UE; and transmit the first configured duration to the source MN via the transceiver.

[0024] In some embodiments, the processor of the target MN is configured to: generate a second configured duration, wherein the second configured duration is used by the UE during the UE's continued CPAC execution condition evaluation, wherein the continued CPAC execution condition evaluation is for one or more candidate PSCells associated with a candidate PCell whose CHO execution condition is fulfilled within at least one candidate PSCell configured for the UE; and transmit the second configured duration to the source MN via the transceiver.

[0025] In some embodiments, the processor of the target MN is configured to: receive a second configured duration from a target secondary node (SN) via the transceiver, wherein the second configured duration is used by the UE during the UE's continued CPAC execution condition evaluation, the continued CPAC execution condition evaluation is for one or more candidate PSCells associated with a candidate PCell in which a CHO execution condition is fulfilled within at least one candidate PSCell configured for the UE; and transmit the second configured duration to the source MN via the transceiver.

[0026] Some embodiments of the present application also provide a source master node (MN). The source MN includes a transceiver and a processor coupled to the transceiver; and the processor is configured to transmit at least one of the following items to a user equipment (UE) via the transceiver: a first configuration set of at least one candidate primary cell (PCell), a second configuration set of at least one candidate primary auxiliary cell group cell (PSCell), a conditional handover (CHO) execution condition set of the at least one candidate PCell, or a conditional PSCell addition or change (CPAC) execution condition set of the at least one candidate PSCell.

[0027] In some embodiments, the processor of the source MN is configured to transmit a first configured duration to the UE via the transceiver, wherein the first configured duration is used by the UE during a CHO execution condition evaluation for one or more candidate PCells associated with a candidate PSCell for which a CPAC execution condition is fulfilled within at least one candidate PCell configured for the UE.

[0028] In some embodiments, the processor of the source MN is configured to: generate the first configured duration; or receive the first configured duration from a target MN via the transceiver.

[0029] In some embodiments, the processor of the source MN is configured to transmit a second configured duration to the UE via the transceiver, wherein the second configured duration is used by the UE during the UE's continued CPAC execution condition evaluation, wherein the continued CPAC execution condition evaluation is for one or more candidate PSCells associated with a candidate PCell in which a CHO execution condition is fulfilled within at least one candidate PSCell configured for the UE.

[0030] In some embodiments, the processor of the source MN is configured to receive the second configured duration from a target MN via the transceiver, and wherein the second configured duration is generated by the target MN or a target secondary node (SN).

[0031] Some embodiments of the present application also provide a target auxiliary node (SN). The target SN includes a transceiver and a processor coupled to the transceiver; and the processor is configured to: generate a configured duration, wherein the configured duration is used by a user equipment (UE) during the UE's continued conditional primary auxiliary cell group cell (PSCell) addition or change (CPAC) execution condition evaluation, the continued CPAC execution condition evaluation is for one or more candidate PSCells associated with a candidate primary cell (PCell) in at least one candidate PSCell configured for the UE and whose conditional switching execution condition is fulfilled; and transmit the configured duration to a target master node (MN) via the transceiver.

[0032] Some embodiments of the present application provide a method performed by a UE. The method includes: receiving at least one of the following from a source master node (MN): a first configuration set of at least one candidate primary cell (PCell), a second configuration set of at least one candidate primary secondary cell group cell (PSCell), a conditional handover (CHO) execution condition set of the at least one candidate PCell, or a conditional PSCell addition or change (CPAC) execution condition set of the at least one candidate PSCell; and in response to at least one of the following: a source secondary cell group (SCG) failure occurs, a source primary cell group (MCG) failure occurs, the CHO execution condition set is not fulfilled, the CPAC execution condition set is not fulfilled, or a failure occurs during CHO execution, performing one of the following: initiating a failure recovery process; initiating CHO execution; and continuing the CHO execution.

[0033] Some embodiments of the present application provide a method performed by a target MN. The method includes: receiving information related to at least one of failure events from a user equipment (UE), wherein the at least one of the failure events includes: a source secondary cell group (SCG) failure occurs; a source primary cell group (MCG) failure occurs; a conditional handover (CHO) execution condition set of at least one candidate primary cell (PCell) is not fulfilled; a conditional primary secondary cell group cell (PSCell) addition or change (CPAC) execution condition set of at least one candidate PCell is not fulfilled; or a failure occurs during CHO execution.

[0034] Some embodiments of the present application provide a method performed by a source MN. The method includes: transmitting to a user equipment (UE) at least one of the following: a first configuration set of at least one candidate primary cell (PCell), a second configuration set of at least one candidate primary secondary cell group cell (PSCell), a conditional handover (CHO) execution condition set of the at least one candidate PCell, or a conditional PSCell addition or change (CPAC) execution condition set of the at least one candidate PSCell.

[0035] Some embodiments of the present application provide a method performed by a target SN. The method includes: generating a configured duration, wherein the configured duration is used by a user equipment (UE) during the UE's continued conditional primary auxiliary cell group cell (PSCell) addition or change (CPAC) execution condition evaluation, wherein the continued CPAC execution condition evaluation is for one or more candidate PSCells associated with a candidate primary cell (PCell) in at least one candidate PSCell configured for the UE and a conditional switching execution condition is fulfilled; and transmitting the configured duration to a target master node (MN).

[0036] 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 method mentioned above performed by a UE or a network node (source MN, target MN, source SN, or target SN).

[0037] 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

[0038] 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 therefore should not be considered to limit the scope of the present application.

[0039] Figure 1 A schematic diagram illustrating a wireless communication system according to some embodiments of the present application is illustrated.

[0040] Figure 2 The diagram illustrates an exemplary flow chart executed by a UE according to some embodiments of the present application.

[0041] Figure 3The diagram illustrates an exemplary flowchart executed by a target SN according to some embodiments of the present application.

[0042] Figure 4 A block diagram illustrating an exemplary device according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0043] The detailed description is intended to describe the preferred embodiments of the present application, but 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 achieved by different embodiments that are intended to be included in the spirit and scope of the present application.

[0044] 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 a specific network architecture and new service context, such as 3GPP 5G, 3GPP LTE Release 8, etc. Please consider that, as network architectures and new service contexts evolve, all embodiments in the present application are also applicable to similar technical issues; and in addition, the terms recorded in the present application may be changed, which will not affect the principles of the present application.

[0045] Figure 1 A schematic diagram illustrating a wireless communication system according to some embodiments of the present application is illustrated.

[0046] like Figure 1 , the wireless communication system 100 may be a dual connectivity system 100, which includes at least one UE 101, at least one MN 102, and at least one SN 103. In particular, for illustrative purposes, Figure 1 The dual connectivity system 100 in FIG. 1 includes one UE 101 shown, one MN 102 shown, and one SN 103 shown. Figure 1 A specific number of UEs 101, MNs 102, and SNs 103 are depicted in FIG. 1 , but please consider that any number of UEs 101, MNs 102, and SNs 103 may be included in the wireless communication system 100.

[0047] refer to Figure 1 , UE 101 may be connected to MN 102 and SN 103 via a network interface (e.g., a Uu interface 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 for NR-NRDC, NGEN-DC, or NE-DC specified in a 3GPP standard document, or an X2 interface for EN-DC specified in a 3GPP standard document). MN 102 may be connected to SN 103 via a network interface (e.g., an Xn interface for NR-NRDC, NGEN-DC, or NE-DC specified in a 3GPP standard document, or an X2 interface for EN-DC specified in a 3GPP standard document). Figure 1 UE 102 may be configured to utilize resources provided by MN 102 and SN 103 to perform data transmission.

[0048] MN 102 may refer to a radio access node that provides a control plane connection to a core network. In one 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.

[0049] 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) and optionally one or more secondary cells (SCells) of the MCG. PCell may provide control plane connectivity to UE 101.

[0050] SN 103 may refer to a radio access node that does not make a control plane connection to the core network but provides additional resources for UE 101. In one 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 a NE-DC scenario, SN 103 may be an ng-eNB. In yet another embodiment of the present application, in an NR-DC scenario or a NGEN-DC scenario, SN 103 may be a gNB.

[0051] SN 103 may be associated with a secondary cell group (SCG). 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).

[0052] 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), a vehicle-mounted computer, a network device (e.g., a router, a switch, and a modem), etc. 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.

[0053] In some other embodiments of the present application, UE 101 may include a wearable device, such as a smart watch, a fitness bracelet, an optical head-mounted display, etc. 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.

[0054] Generally speaking, CHO is performed by the UE when a switching or CHO execution condition is achieved or satisfied or fulfilled. For example, when the CHO execution condition of the candidate PCell is met or fulfilled, CHO execution is performed, and "CHO ​​execution" may be an operation in which the UE determines the candidate PCell whose CHO execution condition is fulfilled as the target PCell and performs a PCell change or switching with respect to the target PCell (for example, the UE performs a RA process to the target PCell). The UE starts evaluating the CHO execution condition immediately after receiving the CHO configuration, and stops evaluating the CHO execution condition once the CHO execution condition is achieved or fulfilled during the CHO execution. The CHO configuration contains configurations for 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).

[0055] CPAC is executed by the UE when one or more switching or CPAC execution conditions are achieved or satisfied or fulfilled. For example, when the CPAC execution conditions of the candidate PSCell are met or fulfilled, CPAC execution is performed, and "CPAC execution" may be an operation in which the UE determines the candidate PSCell whose CPAC execution conditions are fulfilled as the target PSCell and performs PSCell addition or change with respect to the target PSCell (for example, the UE performs a RA process to the target PSCell). The UE starts evaluating the CPAC execution conditions immediately after receiving the CPAC configuration, and stops evaluating the CPAC execution conditions once the CPAC execution conditions are achieved or fulfilled during the CPAC execution. The CPAC configuration (i.e., CPA or CPC configuration) contains configurations for the CPAC candidate PSCells generated by the candidate target SN and the CPAC execution conditions generated by the source SN or source MN.

[0056] As in NR intra-RAN handover or in NR intra-RAN CHO, the preparation and execution phases of the CHO procedure are performed without involving the 5G Core Network (5GC); i.e., preparation messages are exchanged directly between BSs. The release of resources at the source BS during the conditional handover completion phase is triggered by the target BS, with no changes to the Access and Mobility Management Function (AMF) or the User Plane Function UPF.

[0057] Inter-MN handover with or without MN-initiated SN change is used to transfer UE context data from a source MN to a target MN when the UE context at the SN is maintained or moved to another SN. During an inter-MN handover, the target MN decides whether to maintain or change the SN (or release the SN). Only intra-radio access technology (intra-RAT) inter-MN handovers with or without SN change are supported.

[0058] In some cases, in NR-DC, the M-NG-RAN node initiates the procedure by sending an S-Node Add Request message to the S-NG-RAN node. If the CHO Information SN Add IE is included in the S-Node Add Request message, the S-NG-RAN node should consider that the S-NG-RAN node add preparation procedure has been triggered as part of a conditional handover. It may use the Source M-NG-RAN Node ID IE and the Source M-NG-RAN Node UE XnAP ID IE to identify other active S-NG-RAN Node Add Preparations related to this UE. If the Estimated Probability of Arrival IE is included in the CHO Information SN Add IE included in the S-Node Add Request message, the S-NG-RAN node may use that information to allocate the necessary resources for the UE.

[0059] In some other cases, in NR-DC, the M-NG-RAN node initiates the procedure by sending an S-NODE MODIFICATION REQUEST message to the S-NG-RAN node. If the CHO INFORMATION SN MODIFICATION IE is included in the S-NODE MODIFICATION REQUEST message, the S-NG-RAN node shall consider that the S-NG-RAN node modification preparation procedure initiated by the M-NG-RAN node has been triggered as part of a conditional handover. If the Estimated Probability of Arrival IE is included in the CHO INFORMATION SN MODIFICATION IE included in the S-NODE MODIFICATION REQUEST message, the S-NG-RAN node may use the information to allocate the necessary resources to the UE.

[0060] In general, one goal of mobility enhancement in 3GPP Rel-18 is to specify a CHO procedure for candidate SCGs (i.e., specify a CHO procedure including a candidate target MCG and a candidate target SCG for CPC or CPA). The CHO procedure for candidate SCGs may also be named "CHO ​​procedure related to candidate SCGs procedure" or "CHO ​​procedure related to candidate SCGs", etc. For example, the following scenarios may be considered for the CHO procedure for candidate SCGs:

[0061] (1) Scenario 1 "CHO ​​on CPC within SN": 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 1, the PCell is changed, the PSCell is changed but the SN is not changed.

[0062] (2) Scenario 2 "CHO ​​on Inter-SN CPC": CHO from source PCell 1 in SN 1 to candidate (target) PCell 2 in a candidate (target) SN other than SN 1. That is, in scenario 2, the PCell is changed, and the SN is changed.

[0063] (3) Scenario 3 “CHO about CPA”: CHO from single connectivity to NR-DC connection, for example, CHO from source PCell 1 to candidate (target) PCell 2 in the candidate target SN. That is, in scenario 3, single connectivity is changed to dual connectivity.

[0064] In some cases, a CPC or CPA configuration may be associated with a CHO configuration, which may be named "CHO ​​configuration referencing a CPC or CPA configuration", etc. In some other cases, a CPC or CPA configuration may be encapsulated in a CHO configuration, which may be named "CHO ​​configuration containing a CPC or CPA configuration", etc.

[0065] The CHO configuration that refers to or includes CPC or CPA configuration may be configured by the network node for the CHO process regarding the candidate SCG. The configuration of the CHO process regarding the candidate SCG (ie, the CHO configuration that refers to or includes CPC or CPA configuration) may be provided to the UE in a cascaded manner or in a parallel manner.

[0066] When the UE receives a configuration of a CHO procedure for a candidate SCG (i.e., a CHO configuration that refers to or includes a CPC or CPA configuration), for example, when the UE receives a configuration of a candidate (target) PCell, a configuration of CHO execution conditions, a configuration of a candidate (target) PSCell, and a configuration of CPAC execution conditions, the CHO evaluation and the CPC or CPA evaluation may be concurrent or sequential in the following two ways:

[0067] (1) Mode 1: Concurrent CHO evaluation and CPC or CPA evaluation, for example, the UE simultaneously starts to evaluate the CHO execution conditions of the candidate (target) PCell and the CPAC execution conditions of the candidate (target) PSCell (when receiving the configuration of the CHO process for the candidate SCG).

[0068] (2) Method 2: Sequential CHO evaluation and CPC or CPA evaluation. For example, the UE first starts to evaluate the CHO execution conditions of the candidate (target) PCell. When the CHO execution conditions of the candidate (target) PCell are fulfilled, the UE evaluates the CPAC execution conditions of the candidate (target) PSCell.

[0069] Currently, in the above scenarios, several issues need to be addressed. For example, in Method 1, the issue of when to stop CPAC evaluation in the case where the CHO execution condition is first fulfilled or when to stop CHO evaluation in the case where the CPAC execution condition is first fulfilled needs to be addressed. In Method 1 or Method 2, before the CHO execution condition is fulfilled, or before the CHO execution is performed, or during the CHO execution, or before the CPAC execution condition is fulfilled, the UE may detect RLF, such as source SCG failure, target MCG failure and / or source MCG failure, and the issue of how to handle such failure scenarios has been addressed.

[0070] Embodiments of the present disclosure are intended to solve such problems in the scenarios mentioned above. In some embodiments, when CHO evaluation is concurrent with CPAC evaluation, in the case where the CPAC execution condition is fulfilled first, the UE may continue to evaluate the CHO execution conditions for one or more candidate (target) PCells associated with the candidate (target) PSCell whose CPAC execution condition is fulfilled until a source SCG failure occurs, a source MCG failure occurs, or until the configured duration is reached. In some other embodiments, when CHO evaluation is concurrent with CPAC evaluation, in the case where the CHO execution condition is fulfilled first, the UE may continue to evaluate the CPAC execution conditions for one or more candidate (target) PSCells associated with the candidate (target) PCell whose CHO execution condition is fulfilled until a CHO execution failure occurs, a source SCG failure occurs, or until the configured duration is reached.

[0071] In some embodiments, for a failure scenario in the CHO process regarding a candidate SCG (i.e., including at least one of the following: source SCG failure, source MCG failure, CHO execution condition not fulfilled, CPAC execution condition not fulfilled, or CHO execution failure), the UE may execute a specific fault recovery mechanism, i.e., the UE may perform cell selection (e.g., and the UE maintains the latest received configuration of the CHO process regarding the candidate SCG). In these embodiments, if the selected cell is a candidate (target) PCell configured for the CHO process regarding the candidate SCG, the UE performs a switching operation to the target PCell (i.e., the selected candidate (target) PCell), and when the candidate (target) PCell is selected, the switching operation may be an operation for the UE to perform a RA process to the target PCell or for the UE to access the target PCell. In these embodiments, "the CHO execution condition not fulfilled" means that within at least one candidate PCell configured for the CHO process regarding the candidate SCG, the corresponding CHO execution condition of no candidate PCell is fulfilled. “CPAC execution condition is not fulfilled” means that within at least one candidate PSCell configured for the CHO process with respect to the candidate SCG, the corresponding CPAC execution condition of no candidate PSCell is fulfilled.

[0072] In some embodiments, optionally, when the selected cell is a candidate (target) PCell configured for the CHO process regarding the candidate SCG or when the UE performs a switching operation to the target PCell or after successfully completing the switching operation to the target PCell, the UE may select any candidate (target) PSCell associated with the target PCell or the best candidate (target) PSCell to add it as the target PSCell (for example, the UE performs a RA process to the target PSCell or the UE accesses the target PSCell). In some other embodiments, optionally, the UE may evaluate the CPAC execution condition of at least one candidate (target) PSCell associated with the target PCell. If the CPAC execution condition of the candidate (target) PSCell is fulfilled, the UE may also add the candidate (target) PSCell as the target PSCell. Otherwise, the UE may indicate to the target MN that manages the target PCell that the CPAC execution condition has not been fulfilled and / or the corresponding fault event, and the target MN may decide on later actions, for example, whether or how to reconfigure HO / CHO / CPA / CPC / PA / PC. Otherwise, in some other embodiments, the UE performs RRC re-establishment.

[0073] In some embodiments, for a failure scenario in the CHO process regarding a candidate SCG (i.e., including at least one of the following: source SCG failure, source MCG failure, or CPAC execution condition not being fulfilled), if the CHO execution condition of at least one candidate (target) PCell is fulfilled, the UE may perform or continue CHO execution, and "CHO ​​execution" may be an operation in which the UE performs a PCell change or switching operation regarding a target PCell (the target PCell is a candidate PCell whose CHO execution condition is fulfilled). In these embodiments, if the CHO execution is successful, the UE may indicate the corresponding failure event to the target PCell or the target MN. And / or, the UE may select any candidate (target) PSCell or the best candidate (target) PSCell associated with the target PCell to add it as a target PSCell. Alternatively, the UE may evaluate the CPAC execution conditions of one or more candidate (target) PSCells associated with the target PCell. For example, if the CPAC execution condition of a candidate (target) PSCell is fulfilled, the UE may also add the candidate (target) PSCell as a target PSCell. Otherwise, the UE may indicate to the target PCell or target MN that the CPAC execution condition is not fulfilled and / or the corresponding failure event. In these embodiments, if the CHO execution fails, the UE may execute the specific failure recovery mechanism described above.

[0074] More details about the embodiments of the present application will be illustrated in the following text in conjunction with the accompanying drawings.

[0075] Figure 2 An exemplary process of performing a CHO process according to some embodiments of the present application is illustrated. Figure 2 The exemplary process 200 in the embodiment of the present invention may be performed by a UE (eg, Figure 1 Although described with respect to a UE, it should be understood that other devices may be configured to perform the same Figure 2 A similar approach to the one used in this paper.

[0076] exist Figure 2 In the exemplary process 200 shown in FIG. 2 , in operation 201, the UE may receive at least one of the following from the source MN:

[0077] (1) A configuration set of at least one candidate PCell. For simplicity, at least one candidate PCell is labeled as candidate PCell#1. Within candidate PCell#1, there are one or more candidate PCells configured for the CHO process regarding the candidate SCG (including cell information (e.g., CG and / or PCI and / or ARFCN)). For simplicity, the configuration set of candidate PCell#1 is labeled as configuration set#1. Each candidate PCell within the at least one candidate PCell may have its corresponding configuration, including L1 and / or L2 and / or L3 parameters.

[0078] (2) A configuration set of at least one candidate PSCell. For simplicity, at least one candidate PSCell is labeled as candidate PSCell#1. Within candidate PSCell#1, there are one or more candidate PSCells configured for the CHO process regarding the candidate SCG (including cell information (e.g., CG and / or PCI and / or ARFCN)). For simplicity, the configuration set of candidate PSCell#1 is labeled as configuration set #2. Each candidate PSCell within the at least one candidate PSCell may have its corresponding configuration, including L1 and / or L2 and / or L3 parameters.

[0079] (3) CHO execution condition set of candidate PCell#1. Each candidate PCell in candidate PCell#1 may have its corresponding CHO execution condition, including A3 and / or A5 conditional events. The CHO execution conditions of different candidate PCells in candidate PCell#1 may be the same or different. For example, the CHO execution condition set of candidate PCell#1 includes at least one CHO execution condition.

[0080] (4) The CPAC execution condition set of candidate PSCell#1. Each candidate PSCell within candidate PSCell#1 may have its corresponding CPAC execution condition, including A3, A4, A5, B1, B2 and / or B3 conditional events. The CPAC execution conditions of different candidate PSCells within candidate PSCell#1 may be the same or different. For example, the CPAC execution condition set of candidate PSCell#1 includes at least one CPAC execution condition. In some embodiments, candidate PSCell#1 is associated with candidate PCell#1, which means that for one candidate PSCell within candidate PSCell#1, there may be one or more candidate PCells associated with the candidate PSCell within candidate PCell#1; or it means that for one candidate PCell within candidate PCell#1, there may be one or more candidate PSCells associated with the candidate PCell within candidate PSCell#1. At least one candidate PSCell within candidate PSCell#1 can be associated with a candidate PCell within candidate PCell#1, or at least one candidate PCell within candidate PCell#1 can be associated with a candidate PSCell within candidate PSCell#1, which means that the candidate PSCell and the associated candidate PCell can serve the UE at the same time, i.e., a DC scenario.

[0081] In some embodiments, the configuration set of at least one candidate PCell is associated with the configuration set of at least one candidate PSCell, or the configuration set of at least one candidate PSCell is associated with the configuration set of at least one candidate PCell. In some other embodiments, the configuration set of at least one candidate PCell is encapsulated in the configuration set of at least one candidate PSCell, or the configuration set of at least one candidate PSCell is encapsulated in the configuration set of at least one candidate PCell.

[0082] In some embodiments, the UE receives a configuration set of at least one candidate PCell, wherein the configuration set of at least one candidate PSCell is included or encapsulated in the configuration set of at least one candidate PCell. In some other embodiments, the UE receives the configuration set of at least one candidate PCell and the configuration set of at least one candidate PSCell respectively, which means that the configuration set of at least one candidate PCell and the configuration set of at least one candidate PSCell are provided to the UE in parallel.

[0083] For example, configuration set #2 is associated with configuration set #1. In some other embodiments, configuration set #2 is encapsulated in configuration set #1, or configuration set #2 and configuration set #1 are configured for the UE in parallel. In one embodiment, the UE may receive configuration set #1, wherein configuration set #2 is encapsulated in configuration set #1. In another embodiment, the UE may receive configuration set #1 and configuration set #2 separately.

[0084] In operation 202, in response to a source SCG failure, a source MCG failure, a non-fulfillment of a CHO execution condition set, a non-fulfillment of a CPAC execution condition set, and / or a failure during CHO execution, the UE may perform one of the following: initiating a fault recovery process; initiating CHO execution; and continuing CHO execution. Non-fulfillment of the CHO execution condition set means that none of the CHO execution conditions in the CHO execution condition set is fulfilled. Non-fulfillment of the CPAC execution condition set means that none of the CPAC execution conditions in the CPAC execution condition set is fulfilled. CHO execution may be an operation for the UE to perform a PCell change or switch with respect to a target PCell (the target PCell is a candidate PCell whose CHO execution condition is fulfilled), for example, the UE performs a RA process to the target PCell or the UE accesses the target PCell.

[0085] In some embodiments, the CPAC execution condition set is associated with the CHO execution condition set. In some other embodiments, the CPAC execution condition set is included in or encapsulated in the CHO execution condition set. For example, the CPAC execution condition set and the CHO execution condition set are provided to the UE in a cascaded manner, or the CPAC execution condition set and the CHO execution condition set are provided to the UE in a parallel manner. In one embodiment, the UE may receive the CHO execution condition set, wherein the CPAC execution condition set is encapsulated in the CHO execution condition set. In another embodiment, the UE may receive the CHO execution condition set and the CPAC execution condition set separately.

[0086] In some embodiments, in response to initiating a fault recovery process, the UE may perform a cell selection operation to select a cell. In one embodiment, in response to a source SCG failure, a source MCG failure, a CHO execution condition set not being fulfilled, a CPAC execution condition set not being fulfilled, and / or a failure occurring during CHO execution, the network (e.g., the source MN) sends an indication to the UE to instruct the UE to perform a fault recovery process. In one embodiment, in response to a source SCG failure, a source MCG failure, a CHO execution condition set not being fulfilled, a CPAC execution condition set not being fulfilled, and / or a failure occurring during CHO execution, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to initiate a fault recovery process. In response to the selected cell belonging to a candidate PCell configured for a CHO process regarding a candidate SCG (e.g., it belongs to candidate PCell#1 as described above), the UE may determine the selected cell as a target PCell and perform a switching operation to the target PCell (the switching operation may be an operation in which the UE performs a RA process to the target PCell or the UE accesses the target PCell). In response to the selected cell not belonging to the candidate PCell configured for the CHO process with respect to the candidate SCG (e.g., it belongs to candidate PCell#1), the UE may perform an RRC reestablishment process. For example, the cell selected by the UE is a candidate PCell, and the UE performs a handover operation, the handover operation including the UE applying the configuration of the target PCell (i.e., the selected candidate PCell) included in the configuration set #1, and accessing the target PCell.

[0087] In some embodiments, “in response to selecting that the selected cell belongs to a candidate PCell configured for a CHO procedure with respect to a candidate SCG (e.g., it belongs to candidate PCell#1)” or “in response to performing a handover operation to a target PCell” or “in response to successfully completing a handover operation to a target PCell”, the UE may perform at least one of the following:

[0088] (1) Select a candidate PSCell associated with the target PCell, and add the selected candidate PSCell as the target PSCell. For example, from the candidate PSCells configured for the CHO process regarding the candidate SCG, the UE may select any candidate PSCell or select the best cell and / or beam quality candidate PSCell associated with the target PCell, the UE determines the selected candidate PSCell as the target PSCell, and the UE may perform a RA process to the target PSCell or the UE accesses the target PSCell. In one embodiment, "in response to selecting that the selected cell belongs to the candidate PCell configured for the CHO process regarding the candidate SCG (for example, it belongs to candidate PCell#1)" or "in response to performing a switching operation to the target PCell" or "in response to successfully completing a switching operation to the target PCell", the network (for example, the source MN) sends an indication to the UE to instruct the UE to select the candidate PSCell associated with the target PCell. In one embodiment, "in response to selecting that the selected cell belongs to a candidate PCell configured for the CHO process regarding the candidate SCG (e.g., it belongs to candidate PCell#1)" or "in response to performing a switching operation to the target PCell" or "in response to successfully completing the switching operation to the target PCell", the UE may receive an indication from the network (e.g., the source MN) indicating that the UE selects a candidate PSCell associated with the target PCell.

[0089] (2) Performing a CPAC execution condition evaluation on any candidate PSCell configured for the CHO process regarding the candidate SCG, or performing a CPAC execution condition evaluation on any candidate PSCell associated with the target PCell, for example, evaluating one or more CPAC execution conditions of at least one candidate PSCell associated with the target PCell within the configured CPAC execution condition set. In one embodiment, "in response to selecting that the selected cell belongs to a candidate PCell configured for the CHO process regarding the candidate SCG (for example, it belongs to candidate PCell#1)" or "in response to performing a handover operation to the target PCell" or "in response to successfully completing a handover operation to the target PCell", the network (for example, the source MN) sends an indication to the UE to instruct the UE to perform a CPAC execution condition evaluation on any candidate PSCell configured for the CHO process regarding the candidate SCG, or performing a CPAC execution condition evaluation on any candidate PSCell associated with the target PCell. In one embodiment, "in response to selecting that the selected cell belongs to a candidate PCell configured for a CHO process regarding a candidate SCG (for example, it belongs to candidate PCell#1)" or "in response to performing a switching operation to a target PCell" or "in response to successfully completing a switching operation to a target PCell", the UE may receive an indication from the network (for example, a source MN) that the UE performs a CPAC execution condition evaluation on any candidate PSCell configured for the CHO process regarding the candidate SCG or performs a CPAC execution condition evaluation on any candidate PSCell associated with the target PCell.

[0090] In some embodiments, in response to evaluating one or more CPAC execution conditions: in response to fulfilling the CPAC execution conditions of a candidate PSC within at least one candidate PSCell associated with the target PCell, the UE may add the candidate PSCell as a target PSCell (for example, the UE may perform a RA process to the target PSCell or the UE may access the target PSCell), and the added target PSCell may be a candidate PSC for which any CPAC execution condition associated with the target PCell is fulfilled, or a candidate PSC for which the best cell / beam quality CPAC execution condition associated with the target PCell is fulfilled; or in response to not fulfilling one or more CPAC execution conditions, the UE may transmit "information indicating that one or more CPAC execution conditions are not fulfilled" and / or "information related to at least one of the failure events" to the target MN that manages the target PCell. Failure to fulfill one or more CPAC execution conditions means that no CPAC execution condition is fulfilled.

[0091] In one embodiment, at least one of the failure events includes: a source SCG failure occurs; a source MCG failure occurs; a CHO execution condition set is not fulfilled; a CPAC execution condition set is not fulfilled; or a failure occurs during CHO execution.

[0092] In some embodiments, the UE may evaluate the CHO execution condition set and the CPAC execution condition set concurrently. In some other embodiments, the UE may first evaluate the CHO execution condition set, and then, in response to fulfilling the CHO execution condition for the candidate PCell in the CHO execution condition set, the UE may evaluate the CPAC execution condition for "any candidate PSCell associated with the candidate PCell for which the CHO execution condition is fulfilled" in the CPAC execution condition set.

[0093] In some embodiments, the UE may evaluate the CHO execution condition set and the CPAC execution condition set concurrently. In some other embodiments, the UE may first evaluate the CPAC execution condition set, and then, in response to fulfilling the CPAC execution condition for the candidate PSCell in the CPAC execution condition set, the UE may evaluate the CHO execution condition in the CHO execution condition set for "any candidate PCell associated with the candidate PSCell whose CPAC execution condition is fulfilled".

[0094] In some embodiments, "in response to concurrently evaluating the CHO execution condition set and the CPAC execution condition set" and "in response to the CPAC execution condition set of candidate PSCell#1 being fulfilled before the CHO execution condition set of candidate PCell#1 is fulfilled", the UE may perform or continue CHO execution condition evaluation for at least one candidate PCell associated with "the candidate PSCell in which the CPAC execution condition is fulfilled within PSCell#1" until a source SCG failure or a source MCG failure occurs or until a configured duration (labeled as duration #1 for simplicity) is reached. In one embodiment, duration #1 may be configured by the target MN or the source MN. In these embodiments, "the CPAC execution condition set of candidate PSCell#1 is fulfilled before the CHO execution condition set of candidate PCell#1 is fulfilled" means that, within candidate PSCell#1, the corresponding CPAC execution conditions of one or more candidate PSCells may be fulfilled, but until this time within candidate PCell#1, no corresponding CHO execution condition of the candidate PCell is fulfilled, or "the CPAC execution condition set of PSCell#1 is fulfilled before the CHO execution condition set of PCell#1 is fulfilled" means that at least one CPAC execution condition (but not all CPAC execution conditions) within the CPAC execution condition set of PSCell#1 is fulfilled before the CHO execution condition set of PCell#1 is fulfilled.

[0095] In some embodiments, "in response to concurrently evaluating CHO execution conditions and CPAC execution conditions" and "in response to the CHO execution condition set of candidate PCell#1 being fulfilled before the CPAC execution condition set of candidate PSCell#1 being fulfilled", the UE may perform or continue CPAC execution condition evaluation for "at least one candidate PSCell associated with the candidate PCell in which the CHO execution condition is fulfilled" within PCell#1 until a failure occurs during CHO execution or a source SCG failure occurs or until a configured duration (labeled as duration #2 for simplicity) is reached. In one embodiment, duration #2 may be configured by the target MN or target SN. For example, the UE may receive duration #1 and / or duration #2 from the source MN. In these embodiments, "the CHO execution condition set of candidate PCell#1 is fulfilled before the CPAC execution condition set of candidate PSCell#1 is fulfilled" means that, within candidate PCell#1, the corresponding CHO execution conditions of one or more candidate PCells may be fulfilled, but until this time, within candidate PSCell#1, no corresponding CPAC execution condition of the candidate PSCell is fulfilled, or "the CHO execution condition set of PCell#1 is fulfilled before the CPAC execution condition set of PSCell#1 is fulfilled" means that at least one CHO execution condition (but not all CHO execution conditions) within the CHO execution condition set of PCell#1 is fulfilled before the CPAC execution condition set of PSCell#1 is fulfilled.

[0096] Some other embodiments of the present application provide that a target MN or a candidate (target) MN (eg, Figure 1 102) shown in FIG. 103. In an embodiment of the present application, the target MN manages the target PCell whose CHO execution condition is fulfilled, and the candidate (target) MN or candidate target MN manages the candidate (target) PCell configured for CHO with respect to the candidate SCG. Although described with respect to the target MN or the candidate (target) MN, it should be understood that other devices may be configured to perform similar methods. In this process, the target MN or the candidate (target) MN may receive a CHO request from a UE (e.g., Figure 1UE 101 shown in FIG. 1 receives information related to at least one of the failure events. At least one of the failure events may include: a source SCG failure occurs; a source MCG failure occurs; a CHO execution condition set of at least one candidate PCell is not fulfilled; a CPAC execution condition set of at least one candidate PCell is not fulfilled; or a failure occurs during CHO execution. Failure to fulfill the CHO execution condition set means that no CHO execution condition in the CHO execution condition set is fulfilled. Failure to fulfill the CPAC execution condition set means that no CPAC execution condition in the CPAC execution condition set is fulfilled.

[0097] In some embodiments, the target MN or the candidate (target) MN may transmit information related to at least one of the failure events to the source MN.

[0098] In some embodiments, the target MN or candidate (target) MN may generate a configured duration used by the UE during the UE's continued CHO execution condition evaluation for "one or more candidate PCells associated with a candidate PSCell whose CPAC execution condition is fulfilled" within at least one candidate PCell configured for the UE. The target MN or candidate (target) MN may then transmit the configured duration to the source MN.

[0099] In some embodiments, the target MN or candidate (target) MN may generate another configured duration (labeled as duration #2 for simplicity) used by the UE during the UE's continued CPAC execution condition evaluation for "one or more candidate PSCells associated with the candidate PCell whose CHO execution condition is fulfilled" within at least one candidate PSCell configured for the UE. The target MN or candidate (target) MN may then transmit the generated duration #2 to the source MN.

[0100] In some embodiments, the target MN or candidate (target) MN may receive from the target SN a duration #2 used by the UE during the UE's continued CPAC execution condition evaluation for "one or more candidate PSCells associated with a candidate PCell whose CHO execution condition is fulfilled" within at least one candidate PSCell configured for the UE. The target MN or candidate (target) MN may then transmit the duration #2 to the source MN.

[0101] Some additional embodiments of the present application provide that a source MN (e.g., Figure 1The exemplary process of the CHO process performed by the source MN (not shown in the figure) is described in detail. Although described with respect to the source MN, it should be understood that other devices can be configured to perform similar methods. In this process, the source MN can transmit at least one of the following items to the UE: a configuration set of at least one candidate PCell, a configuration set of at least one candidate PSCell, a CHO execution condition set of at least one candidate PCell, or a CPAC execution condition set of at least one candidate PSCell.

[0102] In some embodiments, the source MN may transmit to the UE a configured duration (denoted as duration #1 for simplicity) used by the UE during CHO execution condition evaluation for "one or more candidate PCells associated with a candidate PSCell for which the CPAC execution condition is fulfilled" within at least one candidate PCell configured for the UE. In some embodiments, the source MN may generate duration #1 or receive duration #1 from the target MN or candidate (target) MN.

[0103] In some embodiments, the source MN may transmit to the UE another configured duration (labeled as duration #2 for simplicity) used by the UE during the UE's continued CPAC execution condition evaluation, wherein the continued CPAC execution condition evaluation is for "one or more candidate PSCells associated with the candidate PCell where the CHO execution condition is fulfilled" within at least one candidate PSCell configured for the UE. In some embodiments, the source MN may receive duration #2 generated by the target MN, the candidate (target) MN, or the target SN or the candidate (target) SN from the target MN or the candidate (target) MN. In an embodiment of the present application, the target SN manages the target PSCell where the CPAC execution condition is fulfilled. The candidate (target) SN or the candidate target SN manages the candidate (target) PSCell configured for CHO regarding the candidate SCG.

[0104] Figure 3 The diagram illustrates an exemplary process of receiving fault-related information according to some embodiments of the present application. Figure 3 The exemplary process 300 in the embodiment of the present invention may be performed by a target SN or a candidate (target) SN (e.g., Figure 1 Although described with respect to a target SN or 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 used in this paper.

[0105] exist Figure 3In the exemplary process 300 shown in FIG. 1 , in operation 301, the target SN or candidate (target) SN may generate a configured duration (labeled as duration #1 for simplicity) used by the UE during the UE's continued CPAC execution condition evaluation, wherein the continued CPAC execution condition evaluation is for "one or more candidate PSCells associated with the candidate PCell for which the conditional handover execution condition is fulfilled" within at least one candidate PSCell configured for the UE. In operation 302, the target SN or candidate (target) SN may transmit duration #1 to the target MN or candidate (target) MN.

[0106] The details described in all other embodiments of this application apply to Figure 2 and 3 The exemplary process mentioned above is performed by the UE, the target MN, the candidate (target) MN, the source MN, the target SN or the candidate (target) SN. Figure 2 or Figure 3 The details described in the embodiments or the exemplary processes mentioned above are applicable to all other embodiments of the present application. It should be understood by those skilled in the art that the order of operations in these exemplary processes may be changed and some of the operations in these exemplary processes may be eliminated or modified without departing from the spirit and scope of the present disclosure.

[0107] The following text describes Figure 2 and 3 Specific embodiments 1 and 2 of the exemplary process mentioned above, which are shown and illustrated in the method or performed by the UE, the target MN, the candidate (target) MN, the source MN, the target SN or the candidate (target) SN. According to the first and second embodiments, the UE and the network node perform the following operations. For example, the UE may be Figure 1 The target MN or candidate (target) MN may be a UE 101 shown and illustrated in FIG. Figure 1 The target SN or candidate (target) SN may be MN 102 as shown and illustrated in FIG. Figure 1 The source MN may be SN 103 as shown and illustrated in FIG. Figure 1 The target SN or candidate (target) SN may be Figure 1 SN as shown and illustrated in FIG.

[0108] In an embodiment of the present application, "failure recovery for a CHO process with respect to a candidate SCG" may be defined as follows. The UE performs cell selection (e.g., while the UE maintains the latest received configuration of the CHO process with respect to the candidate SCG). During failure recovery for a CHO process with respect to a candidate SCG:

[0109] (1) If the selected cell is a candidate (target) PCell included in the configuration of the CHO process of the candidate SCG or included in the configuration set of at least one candidate PCell, the UE may perform a handover to the target PCell (i.e., perform a RACH process to the selected candidate (target) PCell, or access the selected candidate (target) PCell). There may be the following two options, Option 1 and Option 2.

[0110] a) Option 1: For example, when a target PCell is selected or a handover (HO) to the selected PCell or the target PCell is successful, the UE may select any candidate (target) PSCell or the best candidate (target) PSCell associated with the target PCell to add it as the target PSCell. Any candidate (target) PSCell or the best candidate (target) PSCell is included in the configuration of the CHO process regarding the candidate SCG or in the configuration set of at least one candidate PSCell. Optionally, for example, when a target PCell is selected or a handover / access to the selected PCell or the target PCell is successful, the UE may receive an indication from the network (e.g., the source MN) indicating that the UE selects a candidate PSCell associated with the target PCell.

[0111] b) Option 2: For example, when a candidate (target) PCell is selected or HO / access to the selected PCell or target PCell is successful, the UE may evaluate the CPAC execution conditions of one or more candidate (target) PSCells associated with the target PCell. The one or more candidate (target) PSCells are included in the configuration of the CHO process regarding the candidate SCG or in the configuration set of at least one candidate PSCell. Optionally, for example, when a candidate (target) PCell is selected or HO / access to the selected PCell or target PCell is successful, the UE may receive an indication from the network (e.g., the source MN) indicating that the UE evaluates the CPAC execution conditions of one or more candidate (target) PSCells associated with the target PCell.

[0112] 1) If the CPAC execution condition of a candidate (target) PSCell associated with the target PCell is fulfilled, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell). If the CPAC execution conditions of more than one candidate (target) PSCell associated with the target PCell are fulfilled, the UE may decide any one of the more than one candidate (target) PSCells as the target PSCell, or decide the best one (for example, the best cell / beam quality) among the more than one candidate (target) PSCells as the target PSCell, and then, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell).

[0113] 2) Otherwise, the UE indicates to the target MN that the CPAC execution condition is not met, for example, indicating that the CPAC execution condition of one or more candidate (target) PSCells associated with the target PCell is not fulfilled. The target MN may decide on later actions, such as whether or how to reconfigure CPA or CPC or PSCell Addition (PA) or Primary Cell (PC). For example, the target MN may decide on subsequent actions related to the reconfiguration of the CPAC process.

[0114] (2) Otherwise, if the selected cell is not a candidate (target) PCell included in the configuration of the CHO process with respect to the candidate SCG or included in the configuration set of at least one candidate PSCell, the UE may perform the RRC re-establishment process.

[0115] Example 1

[0116] Embodiment 1 provides a solution for Method 1 described above. In Method 1, when the UE receives a configuration of a CHO process for a candidate SCG (i.e., a CHO configuration that refers to or includes a CPC or CPA configuration, or a configuration set of at least one candidate PCell, a configuration set of at least one candidate PSCell, a CHO execution condition set of at least one candidate PCell, and a CPAC execution condition set of at least one candidate PSCell), CHO evaluation and CPAC (i.e., CPC or CPA) evaluation may be performed concurrently, for example, the UE simultaneously starts evaluating the CHO execution conditions of the candidate (target) PCell and the CPAC execution conditions of the candidate (target) PSCell (for example, when receiving a configuration of the CHO process for the candidate SCG, or when receiving a configuration set of at least one candidate PCell, a configuration set of at least one candidate PSCell, a CHO execution condition set of at least one candidate PCell, and a CPAC execution condition set of at least one candidate PSCell).

[0117] For approach 1 (concurrent CHO evaluation and CPAC (i.e., CPC or CPA) evaluation), embodiment 1 aims to solve the following problems: when to stop CPAC evaluation in the case where the CHO execution condition is fulfilled first; when to stop CHO evaluation in the case where the CPAC execution condition is fulfilled first; and how to handle failure situations occurring in the CHO process with respect to the candidate SCG. Specifically, embodiment 1 may include the following sub-embodiments (i.e., embodiment 1-1 and embodiment 1-2) in different situations (i.e., "situation a" to "situation j").

[0118] Example 1-1

[0119] In the case where the CPAC execution condition of any candidate PSCell is fulfilled first, embodiment 1-1 is intended to solve the problem of when to stop CHO evaluation and how to handle the failure situation in the case where the CPAC execution condition of any candidate PSCell is fulfilled first. Specifically, embodiment 1-1 may include the following sub-embodiments in different scenarios, namely, embodiment 1-1-1, embodiment 1-1-2, embodiment 1-1-3 and embodiment 1-1-4.

[0120] Example 1-1-1

[0121] In Example 1-1-1, in the case where the CPAC execution condition of the candidate (target) PSCell is fulfilled first, the UE continues to evaluate the CHO execution conditions for one or more candidate PCells associated with the candidate (target) PSCell where the CPAC execution condition is fulfilled until a source SCG failure occurs.

[0122] Scenario a: A source SCG failure occurs but the CHO execution condition for no candidate PCell (i.e., it is associated with a candidate (target) PSCell whose CPAC execution condition is fulfilled) is fulfilled, and Example 1-1-1 may be executed. In scenario a (when a source SCG failure occurs but the CHO execution condition for no candidate PCell is fulfilled), the UE maintains the configuration of the CHO process for the candidate SCG, and the UE sends information related to the SCG failure to the source MN (for example, including an indication that the CPAC execution condition configured for the CHO process for the candidate SCG is fulfilled, and an indication that the CHO execution condition configured for the CHO process for the candidate SCG is not fulfilled). The source MN may reconfigure the UE (for example, reconfigure a new CHO process for the candidate SCG, or reconfigure CHO, handover (HO), CPA, CPC, PSCell addition (PA) or primary cell (PC)). Scenario a may include the following two sub-situations.

[0123] (1) Case a-1: UE receives new configuration. In case a-1, the previous configuration of the CHO process with respect to the candidate SCG is released by the UE, and the UE acts based on the latest configuration.

[0124] (2) Scenario a-2: Source MCG failure occurs (e.g., before the UE receives a new configuration). In scenario a-2, when the source MCG failure occurs, the UE may perform the “failure recovery for the CHO procedure with respect to the candidate SCG” described above, and optionally, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform the “failure recovery for the CHO procedure with respect to the candidate SCG”.

[0125] Example 1-1-2

[0126] In embodiment 1-1-2, in the case where the CPAC execution condition of the candidate (target) PSCell is fulfilled first, the UE continues to evaluate the CHO execution condition for one or more candidate PCells associated with the candidate (target) PSCell whose CPAC execution condition is fulfilled until a source MCG failure occurs.

[0127] Scenario b: A source MCG failure occurs but the CHO execution condition for no candidate PCell (i.e., which is associated with a candidate (target) PSCell for which the CPAC execution condition is fulfilled) is fulfilled, and Example 1-1-2 may be performed. For scenario b (when a source MCG failure occurs but the CHO execution condition for no candidate PCell is fulfilled), one solution is that the UE may perform the "failure recovery for the CHO process regarding the candidate SCG" described above. Optionally, when a source MCG failure occurs but the CHO execution condition for no candidate PCell is fulfilled, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform "failure recovery for the CHO process regarding the candidate SCG".

[0128] For situation b, another solution is that the UE sends information related to the MCG failure to the source SN (including an indication that the CPAC execution condition configured for the CHO process regarding the candidate SCG is fulfilled, and an indication that the CHO execution condition configured for the CHO process regarding the candidate SCG is not fulfilled). The source SN may transmit information related to the MCG failure to the source MN. The source MN may reconfigure the UE via the source SN (for example, reconfigure a new CHO process regarding the candidate SCG, or reconfigure CHO or HO or CPA or CPC or PA or PC). Situation b may include the following two sub-situations.

[0129] (1) Case b-1: UE receives new configuration In case b-1, the previous configuration of the CHO process with respect to the candidate SCG is released by the UE, and the UE acts based on the latest configuration.

[0130] (2) Scenario b-2: Source SCG failure occurs (e.g., before the UE receives a new configuration). In scenario b-2, the UE may perform the “failure recovery for the CHO procedure with respect to the candidate SCG” described above. Optionally, when a source SCG failure occurs, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform “failure recovery for the CHO procedure with respect to the candidate SCG”.

[0131] Example 1-1-3

[0132] In embodiment 1-1-3, in the case where the CPAC execution condition of the candidate (target) PSCell is fulfilled first, the UE continues to evaluate the CHO execution condition for one or more candidate PCells associated with the candidate (target) PSCell whose CPAC execution condition is fulfilled until the configured duration is reached. The source MN or the candidate target MN may configure the duration for evaluating the CHO execution condition after the CPAC execution condition is fulfilled.

[0133] Scenario c: The duration is reached but the CHO execution condition for no candidate PCell (i.e., which is associated with a candidate (target) PSCell for which the CPAC execution condition is fulfilled) is fulfilled, and Embodiment 1-1-3 may be performed. For scenario c (when the duration is reached but the CHO execution condition is not fulfilled), the UE may perform the “failure recovery for the CHO process with respect to the candidate SCG” described above. Optionally, when the duration is reached but the CHO execution condition is not fulfilled, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform “failure recovery for the CHO process with respect to the candidate SCG”.

[0134] Example 1-1-4

[0135] In Embodiment 1-1-1 or Embodiment 1-1-2 or Embodiment 1-1-3, the CHO execution condition of at least one candidate (target) PCell associated with the candidate (target) PSCell whose CPAC execution condition is fulfilled may be fulfilled. If so, the UE may perform a RA process to access the (candidate) target PCell whose CHO execution condition is fulfilled and the (candidate) target PSCell whose CPAC execution condition is fulfilled, and situation d may occur in Embodiment 1-1-1 or Embodiment 1-1-2 or Embodiment 1-1-3.

[0136] Case d: Source SCG failure occurs during CHO execution (e.g., during the RA process to the target PCell, or when the UE switches to or accesses the target PCell). The UE may first perform the RA process to the target PCell, and then perform the RA process to the target PSCell. Simultaneous RA processes are not supported.

[0137] For situation d (when a source SCG failure occurs during CHO execution), one solution is that the UE may stop the CHO execution and then perform the “failure recovery for the CHO process with respect to the candidate SCG” described above. Optionally, when a source SCG failure occurs during CHO execution, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform “failure recovery for the CHO process with respect to the candidate SCG”.

[0138] For scenario d, another solution is that the UE continues CHO execution (for example, continues the RA process to the target PCell or continues access to the target PCell):

[0139] (1) If the CHO is successfully performed (for example, the UE successfully performs the RA procedure to the target PCell or the target MN, or the UE successfully accesses the target PCell or the target MN), then:

[0140] a) The UE may indicate to the target MN that a source SCG failure occurred after the CPAC execution conditions were fulfilled and before CPAC was executed, and / or a source SCG failure occurred during CHO execution. The target MN may decide on later actions, such as whether or how to reconfigure CPA / CPC / PA / PC for the UE.

[0141] b) and / or, the UE may select any candidate (target) PSCell or the best candidate (target) PSCell associated with the target PCell to add it as the target PSCell. Optionally, when the target PCell is selected or when the handover / access to the target PCell is successful or when the CHO is performed successfully, the UE may receive an indication from the network (e.g., the source MN) indicating that the UE selects the candidate PSCell associated with the target PCell, or an indication from the network (e.g., the source MN) indicating that the UE selects the best cell / beam quality candidate PSCell associated with the target PCell.

[0142] c) and / or, the UE may evaluate the CPAC execution condition of at least one candidate (target) PSCell associated with the target PCell. Optionally, when the target PCell is selected or when the handover / access to the target PCell is successful or when the CHO is successfully performed, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform a CPAC execution condition evaluation on any candidate PSCell associated with the target PCell:

[0143] 1) If the CPAC execution condition of a candidate (target) PSCell associated with the target PCell is fulfilled, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell). If the CPAC execution conditions of more than one candidate (target) PSCell associated with the target PCell are fulfilled, the UE may decide any one of the more than one candidate (target) PSCells as the target PSCell, or decide the best one (for example, the best cell / beam quality) among the more than one candidate (target) PSCells as the target PSCell, and then, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell).

[0144] 2) Otherwise, the UE indicates to the target MN that the source SCG fails, and / or the UE indicates to the target MN that the CPAC execution condition is not met (e.g., indicating that the CPAC execution conditions of one or more candidate (target) PSCells associated with the target PCell are not fulfilled), and the target MN may decide on a later action, such as whether or how to reconfigure CPA or CPC or PA or PC. For example, the target MN may decide on a subsequent action related to the reconfiguration of the CPAC process.

[0145] (2) If CHO execution fails (e.g., the RA process to the target PCell or the handover or access to the target PCell fails), the UE may perform the "failure recovery for the CHO process with respect to the candidate SCG" described above. Optionally, when CHO execution fails, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform "failure recovery for the CHO process with respect to the candidate SCG".

[0146] Example 1-2

[0147] In the case where the CHO execution condition of any candidate PCell is fulfilled first, embodiment 1-2 is intended to solve the problem of when to stop CPAC evaluation and how to handle the failure situation in the case where the CHO execution condition of any candidate PCell is fulfilled first. Specifically, embodiment 1-2 may include the following sub-embodiments in different scenarios, namely, embodiment 1-2-1, embodiment 1-2-2, embodiment 1-2-3, embodiment 1-2-4 and embodiment 1-2-5.

[0148] Example 1-2-1

[0149] In Example 1-2-1, in the case where the CHO execution condition of the candidate (target) PCell is fulfilled first, when the CHO execution condition of the candidate (target) PCell is fulfilled, the UE continues to evaluate the CPAC execution conditions for one or more candidate PSCells associated with the candidate (target) PCell whose CHO execution condition is fulfilled until a source SCG failure occurs.

[0150] Scenario e: A source SCG failure occurs but the CPAC execution condition of no candidate PSCell (i.e., it is associated with a candidate (target) PCell whose CHO execution condition is fulfilled) is fulfilled, and Example 1-2-1 can be executed. In scenario e (when a source SCG failure occurs but the CPAC execution condition of no candidate PSCell is fulfilled), the UE performs a CHO execution to the target PCell (e.g., a switch to the target PCell, or a RA process to the target PCell, or access to the target PCell). Optionally, the UE further checks whether the target PCell is available, for example, whether the CHO execution condition of the target PCell that was previously fulfilled is still fulfilled when the source SCG failure occurs, and if so, the UE performs a CHO execution to the target PCell. Alternatively, the UE further checks whether the departure condition of the target PCell is not met when the source SCG failure occurs, and if not, the UE performs a CHO execution to the target PCell. Scenario e may include the following two sub-situations.

[0151] (1) Case e-1: CHO execution failure occurs (e.g., handover to the target PCell fails, or the RA process to the target PCell fails, or access to the target PCell fails). In case e-1, the UE may perform failure recovery for the CHO process with respect to the candidate SCG. Optionally, when CHO execution failure occurs, the UE may receive an instruction from the network (e.g., the source MN) instructing the UE to perform "failure recovery for the CHO process with respect to the candidate SCG".

[0152] (2) Case e-2: CHO is successfully performed (for example, the UE successfully performs a RA procedure to the target PCell or target MN, or the handover or access to the target PCell or target MN is successful):

[0153] a) The UE may indicate to the target MN that the CPAC execution condition without a candidate PSCell (i.e., which is associated with a candidate (target) PCell for which the CHO execution condition is fulfilled) is fulfilled until the source SCG fails. The target MN may decide on later actions, e.g., whether or how to reconfigure CPA or CPC or PA or PC for the UE.

[0154] b) and / or, the UE may select any candidate (target) PSCell or the best candidate (target) PSCell associated with the target PCell to add it as the target PSCell. Optionally, when CHO is performed successfully or when the handover / access / RA process to the target PCell is successful, the UE may receive an indication from the network (e.g., the source MN) indicating that the UE selects the candidate PSCell associated with the target PCell, or an indication from the network (e.g., the source MN) indicating that the UE selects the best cell / beam quality candidate PSCell associated with the target PCell.

[0155] c) and / or, the UE may evaluate the CPAC execution condition of at least one candidate (target) PSCell associated with the target PCell. Optionally, when CHO execution is successful or when the handover / access / RA procedure to the target PCell is successful, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform CPAC execution condition evaluation on any candidate PSCell associated with the target PCell:

[0156] 1) If the CPAC execution condition of a candidate (target) PSCell associated with the target PCell is fulfilled, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell). If the CPAC execution conditions of more than one candidate (target) PSCell associated with the target PCell are fulfilled, the UE may decide any one of the more than one candidate (target) PSCells as the target PSCell, or decide the best one (for example, the best cell / beam quality) among the more than one candidate (target) PSCells as the target PSCell, and then, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell).

[0157] 2) Otherwise, the UE indicates to the target MN that the source SCG has failed, and / or the UE indicates to the target MN that the CPAC execution condition has not been met (for example, indicating that the CPAC execution condition of one or more candidate (target) PSCells associated with the target PCell has not been fulfilled), and the target MN may decide on later actions, for example, whether or how to reconfigure CPA or CPC or PA or PC.

[0158] Example 1-2-2

[0159] In Example 1-2-2, in the case where the CHO execution condition of the candidate (target) PCell is fulfilled first, when the CHO execution condition of the candidate (target) PCell is fulfilled, the UE continues to evaluate the CPAC execution condition for one or more candidate PSCells associated with the candidate (target) PCell whose CHO execution condition is fulfilled until a source MCG failure occurs.

[0160] Case f: A source MCG failure occurs but the CPAC execution condition for no candidate PSCell (ie, which is associated with a candidate (target) PCell for which the CHO execution condition is fulfilled) is fulfilled, and embodiment 1-2-2 may be executed.

[0161] For situation f (when a source MCG failure occurs but the CPAC execution condition for no candidate PSCell is fulfilled), one solution is that the UE may perform a failure recovery for the CHO process with respect to the candidate SCG. Optionally, when a source MCG failure occurs and / or the CPAC execution condition for no candidate PSCell is fulfilled, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform a "failure recovery for the CHO process with respect to the candidate SCG".

[0162] For situation f, another solution is that the UE performs a CHO execution to the target PCell (e.g., a handover to the target PCell or a RA procedure to the target PCell or an access to the target PCell). Optionally, the UE may further check whether the target PCell is available, for example, whether the CHO execution condition of the target PCell that was previously fulfilled is still fulfilled when the source MCG failure occurs, and if so, the UE performs a CHO execution to the target PCell. Alternatively, the UE may further check whether the leaving condition of the target PCell is not met when the source MCG failure occurs, and if not, the UE performs a CHO execution to the target PCell. Specifically:

[0163] (1) If the CHO is successfully executed (for example, the UE successfully performs the RA procedure to the target PCell or the target MN, or the handover or access to the target PCell or the target MN is successful):

[0164] a) The UE may indicate to the target MN that a source MCG failure has occurred and / or that the CPAC execution condition for no candidate PSCell (i.e., which is associated with a candidate (target) PCell for which the CHO execution condition is fulfilled) is fulfilled. The target MN may decide on later actions, e.g., whether or how to reconfigure CPA / CPC / PA / PC for the UE.

[0165] b) and / or, the UE may select any candidate (target) PSCell or the best candidate (target) PSCell associated with the target PCell to add it as the target PSCell. Optionally, when CHO is performed successfully or when the handover / access / RA process to the target PCell is successful, the UE may receive an indication from the network (e.g., the source MN) indicating that the UE selects the candidate PSCell associated with the target PCell, or an indication from the network (e.g., the source MN) indicating that the UE selects the best cell / beam quality candidate PSCell associated with the target PCell.

[0166] c) and / or, the UE may evaluate the CPAC execution conditions of one or more candidate (target) PSCells associated with the target PCell. Optionally, when CHO execution is successful or when a handover / access / RA procedure to the target PCell is successful, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform CPAC execution condition evaluation on any candidate PSCell associated with the target PCell,

[0167] a) If the CPAC execution conditions of a candidate (target) PSCell associated with the target PCell are fulfilled, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell). If the CPAC execution conditions of more than one candidate (target) PSCell associated with the target PCell are fulfilled, the UE may decide any one of the more than one candidate (target) PSCells as the target PSCell, or decide the best one (for example, the best cell / beam quality) among the more than one candidate (target) PSCells as the target PSCell, and then, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell).

[0168] b) Otherwise, the UE indicates to the target MN that the source MCG has failed and / or the CPAC execution conditions have not been fulfilled (e.g., indicating that the CPAC execution conditions of one or more candidate (target) PSCells associated with the target PCell have not been fulfilled), and the target MN may decide on later actions, such as whether or how to reconfigure CPA or CPC or PA or PC.

[0169] (2) If CHO execution fails (e.g., RA process to the target PCell fails, or handover or access to the target PCell fails), the UE may perform the “failure recovery for the CHO process with respect to the candidate SCG” described above. Optionally, when CHO execution fails, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform “failure recovery for the CHO process with respect to the candidate SCG”.

[0170] Example 1-2-3

[0171] In Example 1-2-3, in the case where the CHO execution condition of the candidate (target) PCell is fulfilled first, after the CHO execution condition of the target PCell is fulfilled, the UE immediately performs CHO execution to the target PCell (for example, switching to the target PCell, or RA process to the target PCell, or access to the target PCell), and at the same time, the UE continues to evaluate the CPAC execution condition of the candidate PSCell associated with the target PCell where the CHO execution condition is fulfilled until a CHO execution failure or a source SCG failure occurs.

[0172] Scenario g: A CHO execution failure occurs (e.g., a handover failure to the target PCell, or a RA process failure to the target PCell, or access to the target PCell), but the CPAC execution condition of any candidate PSCell (i.e., which is associated with the candidate (target) PCell whose CHO execution condition is fulfilled) is not fulfilled, and Embodiment 1-2-3 may be performed. In scenario g (when a CHO execution failure occurs but the CPAC execution condition of any candidate PSCell is not fulfilled), the UE may perform the "failure recovery for the CHO process with respect to the candidate SCG" described above. Optionally, when a CHO execution failure occurs, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform "failure recovery for the CHO process with respect to the candidate SCG".

[0173] Scenario h: A source SCG failure occurs after a successful CHO execution, but the CPAC execution conditions of any candidate PSCell are not fulfilled, and Example 1-2-3 can be executed.

[0174] In case h (when source SCG failure occurs after successful CHO execution but CPAC execution conditions are not fulfilled), one solution is that the UE can indicate to the target MN that source SCG failure occurs after successful CHO execution and / or CPAC execution conditions are not fulfilled. The target MN can decide later actions, such as whether or how to reconfigure CPA or CPC or PA or PC for the UE.

[0175] In case h, another solution is that the UE may select any candidate (target) PSCell or the best candidate (target) PSCell associated with the target PCell to add it as the target PSCell. Optionally, when a source SCG failure occurs after a successful CHO execution but the CPAC execution condition is not fulfilled, the UE may receive an indication from the network (e.g., the source MN) indicating that the UE selects a candidate PSCell associated with the target PCell, or an indication from the network (e.g., the source MN) indicating that the UE selects the best cell / beam quality candidate PSCell associated with the target PCell.

[0176] In scenario h, another solution is that the UE may evaluate the CPAC execution condition of at least one candidate (target) PSCell associated with the target PCell. Optionally, when a source SCG failure occurs after a successful CHO execution but the CPAC execution condition is not fulfilled, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform a CPAC execution condition evaluation on any candidate PSCell associated with the target PCell:

[0177] (1) If the CPAC execution condition of a candidate (target) PSCell associated with the target PCell is fulfilled, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell). If the CPAC execution conditions of more than one candidate (target) PSCell associated with the target PCell are fulfilled, the UE may decide any one of the more than one candidate (target) PSCells as the target PSCell, or decide the best one (for example, the best cell / beam quality) among the more than one candidate (target) PSCells as the target PSCell, and then, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell).

[0178] (2) Otherwise, the UE indicates to the target MN that a source SCG failure occurred after a successful CHO execution, and / or the UE indicates to the target MN that the CPAC execution condition is not met (for example, indicating that the CPAC execution condition of one or more candidate (target) PSCells associated with the target PCell is not fulfilled), and the target MN may decide on later actions, for example, whether or how to reconfigure CPA or CPC or PA or PC.

[0179] Example 1-2-4

[0180] In embodiment 1-2-4, in the case where the CHO execution condition of the candidate (target) PCell is fulfilled first, the UE continues to evaluate the CPAC execution condition for one or more candidate PSCells associated with the candidate (target) PCell whose CHO execution condition is fulfilled until the configured duration is reached. The source MN or the candidate target MN or the candidate target SN can configure the duration for evaluating the CPAC execution condition after the CHO execution condition is fulfilled.

[0181] Case i: When the duration is reached but the CPAC execution condition of no candidate PSCell (i.e., which is associated with the candidate (target) PCell whose CHO execution condition is fulfilled) is fulfilled, embodiment 1-2-4 may occur.

[0182] For situation i (when the duration is reached but the CPAC execution condition is not fulfilled), the UE performs CHO execution to the target PCell (e.g., switching to the target PCell, or RA process to the target PCell, or access to the target PCell). Optionally, the UE may further check whether the target PCell is available, for example, whether the CHO execution condition of the target PCell that was previously fulfilled is still fulfilled when the configured duration is reached, and if it is fulfilled, the UE performs CHO execution to the target PCell. Alternatively, the UE may further check whether the leaving condition of the target PCell is not met when the configured duration is reached, and if it is not met, the UE performs CHO execution to the target PCell. Situation i may include the following two sub-situations.

[0183] (1) Case i-1: CHO execution failure occurs (e.g., handover to the target PCell fails, or the RA process to the target PCell fails, or access to the target PCell fails). In case i-1, the UE may perform failure recovery for the CHO process with respect to the candidate SCG. Optionally, when CHO execution failure occurs, the UE may receive an instruction from the network (e.g., the source MN) instructing the UE to perform "failure recovery for the CHO process with respect to the candidate SCG".

[0184] (2) Case i-2: CHO is successfully performed (for example, the UE successfully performs a RA procedure to the target PCell or target MN, or the handover or access to the target PCell or target MN is successful):

[0185] a) The UE may indicate to the target MN that the CPAC execution condition is fulfilled for no candidate PSCell (i.e., it is associated with the candidate (target) PCell for which the CHO execution condition is fulfilled). The target MN may decide on later actions, e.g., whether or how to reconfigure CPA or CPC or PA or PC for the UE.

[0186] b) and / or, the UE may select any candidate (target) PSCell or the best candidate (target) PSCell associated with the target PCell to add it as the target PSCell. Optionally, when CHO is performed successfully or when the handover / access / RA process to the target PCell is successful, the UE may receive an indication from the network (e.g., the source MN) indicating that the UE selects the candidate PSCell associated with the target PCell, or an indication from the network (e.g., the source MN) indicating that the UE selects the best cell / beam quality candidate PSCell associated with the target PCell.

[0187] c) and / or, the UE may evaluate the CPAC execution condition of at least one candidate (target) PSCell associated with the target PCell. Optionally, when CHO execution is successful or when the handover / access / RA procedure to the target PCell is successful, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform CPAC execution condition evaluation on any candidate PSCell associated with the target PCell:

[0188] 1) If the CPAC execution conditions of a candidate (target) PSCell associated with the target PCell are fulfilled, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell). If the CPAC execution conditions of more than one candidate (target) PSCell associated with the target PCell are fulfilled, the UE may decide any one of the more than one candidate (target) PSCells as the target PSCell, or decide the best one (for example, the best cell / beam quality) among the more than one candidate (target) PSCells as the target PSCell. Then, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell).

[0189] 2) Otherwise, the UE indicates to the target MN that the CPAC execution conditions are not fulfilled (e.g., indicating that the CPAC execution conditions of one or more candidate (target) PSCells associated with the target PCell are not fulfilled), and the target MN may decide later actions, such as whether or how to reconfigure CPA / CPC / PA / PC.

[0190] Example 1-2-5

[0191] In embodiment 1-2-1 or embodiment 1-2-2 or embodiment 1-2-3 or embodiment 1-2-4, the CPAC execution condition of at least one candidate (target) PSCell associated with the candidate (target) PCell whose CHO execution condition is fulfilled may be fulfilled. If so, the UE may perform a RA process to access the (candidate) target PCell whose CHO execution condition is fulfilled and the (candidate) target PSCell whose CPAC execution condition is fulfilled, and situation j may occur in embodiment 1-2-1 or 1-2-2 or 1-2-3 or 1-2-4.

[0192] Case j: Source SCG failure occurs during CHO execution (e.g., during the RA process to the target PCell, or when the UE switches to or accesses the target PCell). In case j, the UE first performs the RA process to the target PCell, and then performs the RA process to the target PSCell. Simultaneous RA processes are not supported.

[0193] For situation j (when a source SCG failure occurs during CHO execution), the solution for situation d mentioned in Embodiment 1-1-4 can be applied.

[0194] Example 2

[0195] Embodiment 2 provides a solution for the above-described method 2. In method 2, when the UE receives a configuration of the CHO process for a candidate SCG (i.e., a CHO configuration that refers to or includes a CPC or CPA configuration, or a configuration set of at least one candidate PCell, a configuration set of at least one candidate PSCell, a CHO execution condition set of at least one candidate PCell, and a CPAC execution condition set of at least one candidate PSCell), the CHO evaluation and the CPAC (i.e., CPC or CPA) evaluation may be sequential. For example, the UE first starts evaluating the execution conditions of the candidate (target) PCell. When the CHO execution conditions of the candidate (target) PCell are fulfilled, the UE evaluates the CPAC execution conditions of at least one candidate (target) PSCell associated with the candidate (target) PCell where the CHO execution conditions are fulfilled. Considering when to access the target PCell, there are two ways:

[0196] (1) Mode 2-1: When the CHO execution condition of the candidate (target) PCell is fulfilled, the UE evaluates the CPAC execution condition of one or more candidate (target) PSCells associated with the candidate (target) PCell where the CHO execution condition is fulfilled. If the CPAC execution condition of the candidate (target) PSCell (for example, which is within one or more candidate (target) PSCells associated with the candidate (target) PCell where the CHO execution condition is fulfilled) is also fulfilled, then the UE may perform the RA process to access the (candidate) target PCell where the CHO execution condition is fulfilled and the (candidate) target PSCell where the CPAC execution condition is fulfilled.

[0197] (2) Mode 2-2: When the CHO execution condition of the candidate (target) PCell is fulfilled, the UE performs CHO execution towards this (candidate) target PCell. At the same time, when performing CHO execution, the UE starts to evaluate the CPAC execution conditions of one or more candidate (target) PSCells associated with the candidate (target) PCell whose CHO execution condition is fulfilled.

[0198] Embodiment 2 aims to solve the problem of how to handle failure situations occurring in the CHO process with respect to a candidate SCG. Specifically, Embodiment 2 may include the following sub-embodiments in different scenarios, namely, Embodiment 2-1, Embodiment 2-2, and Embodiment 2-3.

[0199] Example 2-1

[0200] In method 2-1, situation k may occur: "The UE detects RLF in the source SCG before the CHO execution condition of any candidate PCell is fulfilled or before the CHO execution is executed or before the CPAC execution condition of any candidate PSCell is fulfilled." And, in method 2-2, situation m may occur: "The UE detects RLF in the source SCG before the CHO execution condition is fulfilled or before the CHO execution is executed."

[0201] To handle the failure scenario (scenario k or scenario m, for example, a source SCG failure occurs before the CHO execution condition of any candidate PCell is fulfilled or before the CHO execution is performed or before the CPAC execution condition of any candidate PSCell is fulfilled), there are two solutions:

[0202] (1) One solution is that the UE may stop the CHO evaluation or CPAC evaluation and may perform failure recovery for the CHO process with respect to the candidate SCG. Optionally, when a source SCG failure occurs, the UE may receive an instruction from the network (e.g., the source MN) instructing the UE to perform "failure recovery for the CHO process with respect to the candidate SCG".

[0203] (2) Another solution is that the UE maintains the configuration of the CHO process for the candidate SCG, and the UE sends information related to the SCG failure to the source MN (including an indication that the CPAC execution condition configured for the CHO process for the candidate SCG has not been fulfilled, and an indication that the CHO execution condition configured for the CHO process for the candidate SCG has not been fulfilled). The source MN can reconfigure the UE (for example, reconfigure a new CHO process for the candidate SCG, or reconfigure CHO or HO or CPA or CPC or PA or PC). Specifically:

[0204] a) If the UE receives a new configuration, the previous configuration of the CHO procedure regarding the candidate SCG is released by the UE, and the UE acts based on the latest configuration.

[0205] b) If a source MCG failure occurs (e.g., before the UE receives a new configuration), the UE may perform the "failure recovery for the CHO process with respect to the candidate SCG" described above. Optionally, when a source MCG failure occurs, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform "failure recovery for the CHO process with respect to the candidate SCG".

[0206] Example 2-2

[0207] In mode 2-2, situation n "UE detects RLF in source SCG during CHO execution and before CPAC execution conditions of any candidate PSCell are fulfilled" may occur. In order to handle the failure situation (situation n, for example, source SCG fails during CHO execution and before CPAC execution conditions of any candidate PSCell are fulfilled):

[0208] (1) One solution is that the UE may stop CHO execution and may perform failure recovery for the CHO process with respect to the candidate SCG. Optionally, when a source SCG failure occurs, the UE may receive an instruction from the network (e.g., the source MN) instructing the UE to perform "failure recovery for the CHO process with respect to the candidate SCG".

[0209] (2) Another solution is that the UE continues CHO execution (for example, continues the RA process to the target PCell, or continues handover or access to the target PCell):

[0210] a) If the CHO is successfully performed (for example, the UE successfully performs the RA procedure to the target PCell or the target MN, or the UE successfully accesses or switches to the target PCell or the target MN),

[0211] 1) The UE may indicate to the target MN that a source SCG failure occurred during CHO execution and / or CPAC execution conditions were not fulfilled. The target MN may decide on later actions, such as whether or how to reconfigure CPA or CPC or PA or PC for the UE.

[0212] 2) and / or, the UE may select any candidate (target) PSCell or the best candidate (target) PSCell associated with the target PCell to add it as the target PSCell. Optionally, when CHO is performed successfully or the handover / access / RA process to the target PCell is successful, the UE may receive an indication from the network (e.g., the source MN) indicating that the UE selects the candidate PSCell associated with the target PCell, or an indication from the network (e.g., the source MN) indicating that the UE selects the best cell / beam quality candidate PSCell associated with the target PCell.

[0213] 3) and / or, the UE may evaluate the CPAC execution condition of any (any) candidate (target) PSCell associated with the target PCell. Optionally, when the CHO execution is successful or the handover / access / RA process to the target PCell is successful, the UE may receive an indication from the network (e.g., the source MN) indicating that the UE performs a CPAC execution condition evaluation on any candidate PSCell associated with the target PCell:

[0214] -If the CPAC execution condition of a candidate (target) PSCell associated with the target PCell is fulfilled, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell). If the CPAC execution conditions of more than one candidate (target) PSCell associated with the target PCell are fulfilled, the UE may decide any one of the more than one candidate (target) PSCells as the target PSCell, or decide the best one (for example, the best cell / beam quality) among the more than one candidate (target) PSCells as the target PSCell. Then, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell).

[0215] - Otherwise, the UE indicates to the target MN that the source SCG has failed, and / or the UE indicates to the target MN that the CPAC execution condition has not been met (for example, indicating that the CPAC execution condition of one or more candidate (target) PSCells associated with the target PCell has not been fulfilled), and the target MN may decide on later actions, for example, whether or how to reconfigure CPA or CPC or PA or PC.

[0216] b) If CHO execution fails (e.g., RA process to target PCell or handover or access to target PCell fails), the UE may perform the “failure recovery for CHO process with respect to candidate SCG” described above. Optionally, when CHO execution fails, the UE may receive an indication from the network (e.g., source MN) instructing the UE to perform “failure recovery for CHO process with respect to candidate SCG”.

[0217] Example 2-3

[0218] In mode 2-2, situation p "UE detects RLF in source SCG after successful CHO execution and before CPAC execution conditions of any candidate PSCell are fulfilled" may occur. In order to handle the failure situation (source SCG fails after successful CHO execution and before CPAC execution conditions of any candidate PSCell are fulfilled):

[0219] (1) One solution is that the UE can indicate to the target MN that a source SCG failure occurred and / or the CPAC execution conditions of any candidate PSCell were not fulfilled after a successful CHO execution. The target MN can decide on later actions, such as whether or how to reconfigure CPA or CPC or PA or PC for the UE.

[0220] (2) Another solution is that the UE may select any candidate (target) PSCell or the best candidate (target) PSCell associated with the target PCell to add it as the target PSCell. Optionally, when CHO execution or a handover / access / RA process to the target PCell is successful or when the source SCG fails after a successful CHO execution and before the CPAC execution condition of any candidate PSCell is fulfilled, the UE may receive an indication from the network (e.g., the source MN) indicating that the UE selects a candidate PSCell associated with the target PCell, or an indication from the network (e.g., the source MN) indicating that the UE selects the best cell / beam quality candidate PSCell associated with the target PCell.

[0221] (3) Another solution is that the UE may evaluate the CPAC execution condition of any (any) candidate (target) PSCell associated with the target PCell. Optionally, when CHO execution or handover / access / RA procedure to the target PCell is successful or when the source SCG fails after a successful CHO execution and before the CPAC execution condition of any candidate PSCell is fulfilled, the UE may receive an indication from the network (e.g., the source MN) instructing the UE to perform CPAC execution condition evaluation on any candidate PSCell associated with the target PCell:

[0222] a) If the CPAC execution conditions of a candidate (target) PSCell associated with the target PCell are fulfilled, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell). If the CPAC execution conditions of more than one candidate (target) PSCell associated with the target PCell are fulfilled, the UE may decide any one of the more than one candidate (target) PSCells as the target PSCell, or decide the best one (for example, the best cell / beam quality) among the more than one candidate (target) PSCells as the target PSCell, and then, the UE may add the target PSCell (for example, perform a RACH process toward the target PSCell or access the target PSCell).

[0223] b) Otherwise, the UE indicates to the target MN that a source SCG failure occurred after a successful CHO execution, and / or the UE indicates to the target MN that the CPAC execution condition is not met (for example, indicating that the CPAC execution condition of one or more candidate (target) PSCells associated with the target PCell is not fulfilled), and the target MN may decide on later actions, for example, whether or how to reconfigure CPA or CPC or PA or PC.

[0224] Figure 4 A block diagram of an exemplary device 400 is illustrated according to some embodiments of the present disclosure. Figure 4 As shown in , apparatus 400 may include at least one processor 406 and at least one transceiver 402 coupled to the processor 406.

[0225] Although in this figure, elements such as at least one transceiver 402 and processor 406 are described in the singular, please consider the plural unless it is explicitly stated to be limited to the singular. In some embodiments of the present application, the transceiver 402 can be divided into two devices, such as a receiving circuit system and a transmitting circuit system. In some embodiments of the present application, the device 400 may further include an input device, a memory and / or other components.

[0226] In some embodiments of the present application, the device 400 may be a UE, a target MN, a source MN, a target SN, or a source SN. The transceiver 402 and the processor 406 may interact with each other to execute the above (for example, Figures 1 to 3 The operations described in any of the above regarding the UE, target MN, source MN, target SN or source SN.

[0227] In some embodiments of the present application, the device 400 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 cause the processor 406 to implement the method described above with respect to the UE. For example, when the computer-executable instructions are executed, the processor 406 interacts with the transceiver 402 to perform Figures 1 to 3 The operations described in UE, target MN, source MN, target SN or source SN.

[0228] It should be understood by those skilled in the art that the operations or steps of the methods described in conjunction with the various 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, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. In addition, in some aspects, the operations or steps of the methods may reside as one or any combination or a set of codes and / or instructions on a non-transitory computer-readable medium that can be incorporated into a computer program product.

[0229] Although the present disclosure is described with respect to specific embodiments of the present disclosure, it is apparent that many substitutions, modifications and variations may be apparent to those skilled in the art. For example, the various components of the embodiments may be interchanged, added or replaced in other embodiments. Moreover, all elements in each figure are not necessary for the operation of the disclosed embodiments. For example, a person of ordinary skill in the art of the disclosed embodiments will be able to make and use the teachings of the present disclosure by simply adopting elements of independent technical solutions. Therefore, the embodiments of the present disclosure set forth herein are intended to be illustrative rather than restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure.

[0230] In this document, the term "includes", "including" or any other variation thereof is intended to cover non-exclusive inclusion, so that the process steps, methods, articles or equipment containing a series of elements do not only contain those elements, but may contain other elements that are not explicitly listed or inherent to this process step, method, article or equipment. The "a, an" in front of the element, etc., do not exclude the presence of additional identical elements in the process steps, methods, articles or equipment containing the elements without further constraints. And, the term "another" is defined as at least the second or more. The term "having" used herein, etc. is defined as "including". For example, expressions such as "A and / or B" or "at least one of A and B" may include any and all combinations of words listed 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 words "first", "second", etc. are only used to clearly illustrate the embodiments of the present application, but are not used to limit the essence of the present application.

Claims

1. A user equipment UE, comprising: Transceiver; and a processor coupled to the transceiver, wherein the processor is configured to: receiving, via the transceiver, from a source master node MN, at least one of the following: a first configuration set of at least one candidate primary cell PCell, a second configuration set of at least one candidate primary secondary cell group cell PSCell, a conditional handover CHO execution condition set of the at least one candidate PCell, or a conditional PSCell addition or change CPAC execution condition set of the at least one candidate PSCell; and In response to at least one of the following: a source secondary cell group SCG failure occurs, a source primary cell group MCG failure occurs, the CHO execution condition set is not fulfilled, the CPAC execution condition set is not fulfilled, or a failure occurs during CHO execution, performing one of the following: Initiate the failure recovery process; Initial CHO execution; and Continue with the CHO protocol.

2. The UE according to claim 1, wherein: To receive the at least one of the first configuration set or the second configuration set, the processor of the UE is configured to: receiving the first configuration set, wherein the second configuration set is encapsulated in the first configuration set; or The first configuration set and the second configuration set are received respectively.

3. The UE according to claim 1, wherein: To receive the at least one of the CHO execution condition set or the CPAC execution condition set, the processor of the UE is configured to: receiving the CHO execution condition set, wherein the CPAC execution condition set is encapsulated in the CHO execution condition set; or The CHO execution condition set and the CPAC execution condition set are received respectively.

4. The UE according to claim 1, wherein: In response to initiating the failure recovery process, the processor of the UE is configured to: performing a cell selection operation to select a cell; In response to the selected cell belonging to the at least one candidate PCell, determining the selected cell as a target PCell and performing a handover operation to the target PCell; or In response to the selected cell not belonging to the at least one candidate PCell, a radio resource control (RRC) reestablishment procedure is performed.

5. The UE according to claim 4, wherein: In response to selecting that the selected cell belongs to the at least one candidate PCell or in response to performing the handover operation to the target PCell or in response to successfully completing the handover operation to the target PCell, the processor of the UE is configured to perform at least one of the following: Select a candidate PSCell associated with the target PCell and add the selected candidate PSCell as a target PSCell; or One or more CPAC execution conditions within the CPAC execution condition set are evaluated for at least one candidate PSCell associated with the target PCell.

6. The UE according to claim 5, wherein: In response to evaluating the one or more CPAC execution conditions, the processor of the UE is configured to: In response to fulfillment of a CPAC execution condition of a candidate PSCell within the at least one candidate PSCell associated with the target PCell, adding the candidate PSCell as the target PSCell; or In response to the one or more CPAC execution conditions not being fulfilled, transmitting, via the transceiver, at least one of the following to a target master node MN that manages the target PCell: Information indicating that the one or more CPAC execution conditions have not been fulfilled; or Information related to at least one of the failure events.

7. The UE of claim 1, wherein the at least one of the failure events comprises: The source SCG failure occurs; The source MCG failure occurs; the failure to fulfill the CHO execution condition set; the failure to fulfill the set of CPAC execution conditions; or The fault occurs during execution of the CHO.

8. The UE of claim 1, wherein the processor of the UE is configured to: concurrently evaluating the CHO execution condition set and the CPAC execution condition set; or The CHO execution condition set is first evaluated, and in response to the CHO execution condition for the candidate PCell in the CHO execution condition set being fulfilled, the CPAC execution condition in the CPAC execution condition set is evaluated for the candidate PSCell associated with the candidate PCell whose CHO execution condition is fulfilled.

9. The UE according to claim 8, wherein: In response to concurrently evaluating the CHO execution condition set and the CPAC execution condition set and in response to the CPAC execution condition set of the at least one candidate PSCell being fulfilled before the CHO execution condition set of the at least one candidate PCell is fulfilled, the processor of the UE is configured to: CHO execution condition evaluation is continued for at least one candidate PCell associated with the candidate PSCell for which the CPAC execution condition is fulfilled within the at least one candidate PSCell until the source SCG failure occurs or until a first configured duration is reached.

10. The UE according to claim 8, wherein: In response to concurrently evaluating the CHO execution condition and the CPAC execution condition and in response to the CHO execution condition set of the at least one candidate PCell being fulfilled before the CPAC execution condition set of the at least one candidate PSCell being fulfilled, the processor of the UE is configured to: CPAC execution condition evaluation is continued for at least one candidate PSCell associated with the candidate PCell whose CHO execution condition is fulfilled within the at least one candidate PCell until the failure occurs during the CHO execution or until a second configured time duration is reached.

11. A target master node MN, comprising: Transceiver; and a processor coupled to the transceiver, wherein the processor is configured to receive information related to at least one of the failure events from a user equipment (UE) via the transceiver, wherein the at least one of the failure events comprises: A source secondary cell group SCG failure occurs; A source master cell group MCG failure occurs; The conditional handover CHO execution condition set of at least one candidate primary cell PCell is not fulfilled; A conditional primary secondary cell group cell PSCell that does not fulfill at least one candidate PCell adds or changes the CPAC execution condition set; or A failure occurred during CHO execution.

12. The target MN of claim 11, wherein the processor of the target MN is configured to transmit the information related to the at least one of the failure events to a source MN via the transceiver.

13. The target MN of claim 11, wherein the processor of the target MN is configured to: generating a first configured duration, wherein the first configured duration is used by the UE during the UE continuing CHO execution condition evaluation for one or more candidate PCells associated with a candidate PSCell for which a CPAC execution condition is fulfilled within at least one candidate PCell configured for the UE; and The first configured duration is transmitted to a source MN via the transceiver.

14. The target MN of claim 11, wherein the processor of the target MN is configured to: generating a second configured duration, wherein the second configured duration is used by the UE during the UE continuing CPAC execution condition evaluation for one or more candidate PSCells associated with a candidate PCell for which a CHO execution condition is fulfilled within at least one candidate PSCell configured for the UE; and The second configured duration is transmitted to a source MN via the transceiver.

15. The target MN of claim 11, wherein the processor of the target MN is configured to: receiving, via the transceiver, a second configured duration from a target auxiliary node SN, wherein the second configured duration is used by the UE during the UE continuing CPAC execution condition evaluation for one or more candidate PSCells associated with a candidate PCell for which a CHO execution condition is fulfilled within at least one candidate PSCell configured for the UE; and The second configured duration is transmitted to a source MN via the transceiver.

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